Barapukuria 250MW Coal mine specifications

1

Bangladesh Power

Development Board

Extension of Barapukuria Coal Fired Thermal

Power Station by 250 MW (3rd

Unit)

Tender Documents

Part B

Technical Requirements

Volume 1 of 2

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B0 General Specification

0.1 Subject of Specification

0.2 General Auxiliary Systems

0.2.1 Purpose of the Plant

0.2.2 Site conditions- environmental conditions

0.2.2.1 Location of site

0.2.2.2 Transportation and access road for site

0.2.2.3 Meteorological condition

0.2.2.3.1 General

0.2.2.3.2 Rainfall

0.2.2.3.3 Temperature and humidity

0.2.2.3.4 Earthquake

0.2.2.3.5 Wind

0.2.2.3.6 Flood water level condition

0.2.2.3.7 Geological conditions

0.2.3 Layout

0.2.4 Configuration

0.2.5 General technical requirements of the Plant

0.2.5.1 Design requirements

0.2.5.2 Outline description of generating facilities

0.2.5.3 Main powerhouse including control building

0.2.5.4 Civil

0.2.6 Mode of operation

0.2.7 Environmental conditions and emission control standards

0.2.7.1 Environmental conditions

0.2.7.2 Ambient standards and emission standards

0.2.8 Fuel

0.2.8.1 Characteristic of coal

0.2.8.2 Ash

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0.2.9 Waste and waste water

0.3 Supply and Services

0.3.1 General

0.3.2 Scope of engineering services

0.3.3 Common equipment 'and services

0.3.3.1 General

0.3.3.2 Mechanical

0.3.3.3 Electrical, instrumentation and control

0.3.3.4 Civil

0.3.4 Packing and transportation

0.3.5 Documentation

0.3.5.1 Documentation with Tender

0.3.5.2 Documentation after award of Contract

0.3.5.3 Requirements for documentation::

0.3.6 Erection, commissioning and testing

0.3.7 Training of Employer's personnel

0.3.7.1 General

0.3.7.2 Training in the Contractor's country

0.3.7.3 Training at site

0.3.8 Spare parts, tools, appliances, and consumable

0.3.8.1 Spare parts

0.3.8.2 Tools and appliances

0.3.8.3 Consumables

0.3.9 Maintenance works

0.3.10 Options

0.3.10.1 Option: Later realization of Power Unit 3

0.3.10.2 Option: l-.Maintenance works of the whole

Plant

0.4 Interfaces

0.4.1 Limits of supply

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0.4.2 Interfaces to existing facilities on site

0.4.3 Metering

0.4.4 Communication systems

0.5 Form sheets (Data Sheets)

0.6 General Technical Requirements

0.6.1 General requirements

0.6.2 Standards and codes

0.6.3 Plant and equipment identification (e.g. Power Plant

Coding System KKS)

0.6.4 Marking and labeling of crates and packages

0.6.5 Corrosion protection coaling and galvanizing

0.6.6 Vibration

0.6.7 Standardization of makes

0.6.8 Accessibility

0.6.9 Signs

0.6.10 Units of measurement

0.6.11 Ways, stairs, ladders, balustrades

0.6.12 Hazardous areas fire protection provisions

0.6.13 Maintenance isolation

0.6.14 Materials

0.6.15 Pre-service cleaning and protection of plant equipment

0.6.16 Mechanical equipment

0.6.16.1 Pumps

0.6.16.2 Piping and accessories

0.6.16.2.1 Standards and general

conditions

0.6. 16.2.2 Material and construction

standards

0.6.16.2.3 Bolts and nuts

0.6.16.2.4 Pipe supports and anchors

0.6.16.2.5 Cleaning at workshop

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0.6.16.2.6 Cleaning at site

0.6.16.2.7 Wall boxes and collars

0.6. 16.2.8 Expansion and flexibility

0.6.16.3 Piping design criteria

0.6.16.4 Welding and heat treatment

0.6.16.4.1 Responsibility

0.6.16.4.2 Required documents

0.6. I 6.4.3 Welding procedure

qualification

0.6.16.4.4 Personnel qualification

0.6. 16.4.5 Welding process

0.6.16.4.6 Pre-heating and heat

treatment

0.6. 16.4.7 Documentation

0.6.16.5 Valves, steam traps, condensate drainers,

safety valves, control valves

0.6.16.6 Insulation

0.6.16.7 Vessels, tanks, heat exchanger

0.6.17 Electrical equipment and works

0.6.17.1 Standards

0.6.17.2 Standard voltages

0.6.17.3 Climatic conditions

0.6.17.4 Inductive interferences

0.6.17.5 Color code system for switchgear, for local switching measurement-control-signaling cabinets and for mimic diagrams

0.6.17.6 Protection class for electrical operational equipment and control and monitoring equipment

0.6.17.7 Protective measures

0.6.17.8 Auxiliary equipment

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0.6.17.9 Requirements for local cubicles and local housings for e.g. switchgear, control, measurement and signaling equipment

0.6.17.10 Local control points and level control

cabinets

0.6.17.11 Terminal boxes and terminal cabinets

0.6.17 .12 Explosion proof equipment

0.6.17 .13 Keys and key cabinets

0.6.17. I 4 Electric motors

0.6.17.14.1 High voltage motors

0.6.17 .14.2 Low voltage AC motors

0.6.17 .14.3 Actuator drives

0.6.17.14.4 DC motors

0.6.17.14.5 Painting

0.6.17 .14.6 Protection against explosion hazards

0.6.17.14.7 Frequency converters

0.6.17 .14.8 Tests

0.6.17 .14.9 Motor list

0.6.17 .14.10 Labels

0.6.18 Instrumentation and control

0.6.18.1 Measuring units

0.6.18.2 Sizes of indicators, recorders, etc.

0.6.18.3 Protection and safety interlocks

0.6.18.4 Special local conditions

0.6.18.5 Tests

0.6.18.6 Field equipment

0.6.18.6.1 Measuring systems/transmitters

0.6.18.6.2 Flow measurements

0.6.18.6.3 Temperature measurements

0.6.18.6.4 Pressure measurements

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0.6. 18.6.5 Analyses measurements

0.6. 18.6.6 Level measurements

0.6. 18.6.7 Electrical measurements

0.6. 18.6.8 Position measurements

0.6. 18.6.9 Contact devices

0.6.18.6.10 Vibration measurements.

0.6.18.6.11 Control valves

0.6.18.6. 12 Actuators

0.6.18.6.13. Local instrumentation

0.6.18.7 Racks, junction boxes

0.6.18:8 Control cubicles

0.6.18.9 Programmable logic controller

0.6.18.10 Transmitter racks and piping

0.7 Inspection and Testing

0.7.1 General

0.7.1.1 Workshop manufacturing and pre-assembly

0.7.1.2 Works inspections

0.7.2 Testing during manufacturing

0.7.2.1 Material tests

0.7.2.2 Tests at site

0.7.2.2.1 General remarks

0.7.2.2.2 Hydraulic tests

0.7.2.2.3 Test runs and functional tests

0.7.2.2.4 Visual inspection, checking of

dimensions, test instruments

0.7.2.3 Manufacturing tests

0.7.2.3.1 Welding

0.7.2.3.2 Pressure testing

0.7.2.3.3 Testing of corrosion

protection

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0.7.2.4 Mechanical equipment

0.7.2.5 Electrical equipment

0.7.2.6 Control and monitoring equipment

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Table of Contents of the Tender Documents, Part B

• Section B0: General Technical Specification

• Section B I : Steam Generator Plant

• Section B2: Steam Turbine Plant with Condensate and Steam System

• Section B3: Coal Handling System

• Section B4: Air and Flue Gas System

• Section B5: Ash Handling System

• Section B6: Water Storage and Treatment Systems

• Section B7: Auxiliary Systems

• Section B8: Electrical and Associated Works

• Section B9: Instrumentation and Control Works

• Section B 10: Communication, Clock and Surveillance Systems

• Section B11: Civil Works

• Section B12: Workshops, Stores and Vehicles

• Annexes

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General Specification

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B0. General Specification

0.1 Subject of Specification

This section forms an integral part of the Tender Documents issued by the Bangladesh Power Development Board, Dhaka.

0.2 General Auxiliary Systems All the auxiliary systems needed for the trouble-free operation of the unit have to be designed accordingly. The main auxiliary common systems are listed hereunder: This list is not limited to the systems below, but the contractor has to supply, erect and commission all the general auxiliaries necessary for the operation of the unit at M.C.R: • Coal Processing and Coal conveyor system • Ash handling, ash transport and ash pond • Raw water system, dc-mineralized water and potable water • Waste water treatment system • Pressurized air system • Laboratory • Auxiliary closed circuit cooling system • The fire fighting system • All ancillary buildings and services • 6.6 KV and 440/220 V switch-gear rooms • Switchgear room and "relay room'

0.2.1 Purpose of the Plant - intent

It is the intention of the Bangladesh Power Development Board to install a thermal power plant unit for a total capacity of 250 MW at the Barapukuria Steam Power Plant, in order to meet the electricity power demand. The Plant shall be coal fired and equipped with reheater and all auxiliary and ancillary systems. The Contractor shall cover all works for the Engineering, procurement, construction and commissioning of the whole Plant on a turnkey basis. In order to transmit the generated electrical power to 230 kV grid network a step up power plant substation shall be included. The boilers shall be open-air installed for firing with coal.

The steam turbine condensers shall be - water - cooled. In order to cool the condenser cooling water, cooling towers shall be constructed.

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The equipment of the Plant shall be designed in accordance with the re-quirements contained in the Tender Documents and as illustrated on the Tender Drawings attached. Highest reliability and availability, convenience of operation and maintenance, neat and orderly arrangement, are of utmost importance. The functional requirements of the various systems and the pleasing physical appearance of the completed Plant shall also be taken into account. Due care shall be undertaken concerning the environmental impact out of the Plant and sufficient protective measures shall be incorporated in the design of the Plant for envirolUl1ent protection especially on air pollution, water pollution and noise. The environment protection measures shall be done in accordance with the Environment Protection Guidelines of UNDP, ADB, World Bank and Environmental Protection and Emission Control Standards of Bangladesh. In all instances, the listing of items of the Plant shall be understood as general, and shall include upon completion, even if not specifically men-tioned, other necessary components and appurtenances required for proper, continuous and reliable commercial operation of the complete installation, including any and all auxiliary and ancillary systems.

0.2.2 Site conditions - environmental conditions

The following information on local conditions is investigated or compiled by the Owner/Owner's Representative. The Contractor is hereby in no way relieved from his duties of carrying out the investigations required for satisfactory performance of his works, before issuing the Bid and during execution of the works.

0.2.2.1 Location of site

Barapukuria power Plant site is located in flat land of the Northwestern "corner" of Bangladesh at about 45 km east of the district headquarters of Dinajpur, 20 km east to the border of India. The north-south gauge railway passes through the east part of the site.

The site is located about 1 km north of the coal mine mouth under construc-tion.

The only large industrial area nearby is this coal mine including its residential complexes.

The nearest town is Phulbari, a Thana (Upazila) headquarter as primary administrative center of the country. Phulbari is located about 6 km south of the site.

The major railway junction and surrounding township Parbatipur is about 16 km to site. The railway is connected to site.

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The Maddhapara Hard Rock Mining Project, a separate large scale indus-trial project is located 12 km east of the site.

To reach site from Dhaka by car needs approximately 6 - 7 hours at normal climatic conditions. The closest airport to site is Saidpur. It takes about 1 hour by car from site to the airport. The airport is in operation now.

Metalled road is connecting Dinajpur, Phulbari, Parbatipur, Saidpur and site.

The area is situated at approximately 30 m over sea level. The groundwater flow goes from north to south. For cooling, industrial and housing purposes of the existing 2x125 MW plant, the ground water is being pumped from deep wells gathering area at north of site. Discharge water from coal mine after required treatment will be used as cooling water and the existing deep tube well water will be used for potable water & demi water production of the proposed 250 MW. The waste water/sewage water after suitable treatment shall be dumped in a soakaway at the south site of site.

The bottom ash from the boiler and the fly ash from boiler &electrical precipitator shall be dumped in a pond on site. These ashes shall be transported wet and during the dry time of the year the ash shall be wetened by water. The water leaving the pond shall be treated in such a way that it will be suitable for irrigation or for pumping away to the nearby river Tillay.

A dry ash conveyor transportation and dumping system shall be considered as an option.

0.2.2.2 Transportation and access road for site

Access road for site for the facility of transportation, a metal road from the end of Parbatipur/ Fulbari up to Barapukuria Power Station site is being used.

Transportation for construction and erection material

In Bangladesh, inland transportation of all imported materials is done by rail and road.

In general, the ordinary equipment and materials can be transported to the requested places by road and rail. However, a bulk of heavy equipment and machinery such as Generator Stator, Steam Drum and etc. for the coal fired power Plant are difficult to transport to near the project site other than waterway.

Loads probably more than 150 t will need to be transported for the Power Plant. A scheme that the Contractor of the Power Plant may consider most feasible would be to transport the equipment by river upto nearest possible location and then to transport by rail or road. The Contractor shall fix up the transportation possibilities in detail for the tender.

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0.2.2.3 Meteorological condition

0.2.2.3.1 General

Bangladesh has a subtropical monsoon climate and weather patterns are governed by the south-east Asian monsoon system. The year can be roughly divided into the rainy season from May through September and the dry season from October through April. Meteorological information relevant to the Barapukuria site is available from weather stations at Dinajpur (880 41'E, 25° 38'N) and Rangpur (89° 15'E,25° 45'N). These stations are about 30 km west and east respectively from the Plant site. The data are available at Bangladesh Meteorological Department.

0.2.2.3.2 Rainfall

Rainfall from May through September contributes over 85% of the annual total. However, rainfall intensives tend to be high and concentrated in a� comparatively small number of heavy storms, even when monthly rainfall figures are relatively low. The monthly precipitation data are as follows (in mm):

Average in Dinajpur

Average in Rangpur

Peak

at one day

Maximum per month

January 11 6

February 13 15

March 16 27

April 70 110

May 241 307 85 307

June 297 499 140 700

July 592 660 142 640

August 442 430 132 442

September 307 412 431 890

October 144 120 104 242

November 7 7

December 16 17

Annual 2,008 2,812

Note: Above mentioned data are very old, probably in the period of 1981- 1988

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0.2.2.3.3 Temperature and humidity

The data of temperature and humidity are as follows: (According to the temperature data in 1988, the maximum temperature is 40°C and the minimum temperature 10.6°C. The mean temperature is about 25°C and relative humidity is generally high.)

Dinajpur Rangpur

Max.

Temp. in

'88 (0C)

Min.

Temp. in

'88 (0C)

Mean.

Temp.81

- 88 (0C)

Mean

Hum.'81

- 88 (%)

Max.

Temp. in

'88 (0C)

Min.

Temp. in

'88 (0C)

Mean.

Temp.81

- 88 (0C)

Mean

Hum.'81

- 88 (%)

January 24.9 11.6 18.4 70 25.3 11.7 16.8 79

Feb. 27.5 14.2 70.9 61 29.0 145 19.0 71

March 33.5 13.5 25.4 54 33.7 12.6 23.6 63

April 40.0 10.5 28.0 57 37.5 16.8 26.5 69

May 36.3 19.0 28.2 70 35.6 20.8 .27.3 79

June 37.5 23.8 29.0 76 36.3 23.9 28.7 84

July 34.0 23.0 28.5 82 34.1 22.5 28.4 87

August 36.7 22.1 29.3 82 32.4 26.2 28.8 85

Sept. 32.0 25.6 28.4 84 31.8 25.4 27.8 87

October 31.5 22.2 27.5 76 31.4 22.6 26.2 84

Nov. 28.8 16.4 23.7 70 28.3 17.5 22.1 79

Dec. 26.5 13.1 19.6 72 26.0 14.1 18.3 81

Annual 32.4 17.9 25.6 71 31.8 19. 1 24.5 79

0.2.2.3.4 Wind

The wind in Barapukuria changes its direction according to seasons. The wind tends to blow from the west, or in dry season from northeast and from the east or the southeast in rainy season. The predominant wind direction is generally east-west. The wind speed is relatively moderate and it is said that there is also a high proportion of calm days through the year.

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Monthly average prevailing wind speed (knots and direction/1knot = 0.514 m/s)

Rangpur (1979-1988)

YEAR JAN FED MAR APL MAY JUN JUL AUG SEP OCT NOV

SPD DIR SPD DIR SPD DIR SPD DIR SPD DIR SPD DIR SPD DIR SPD DIR SPD DIR SPD DIR SPD DIR SPD

1979 3 N S N 6 NNW 5 S 3 S 5 SE 4 SE 5 SE 5 S 3 N 3 N 3

1980 4 W 4 NE 4 E 3 E 4 E 4 SE 4 SE 4 SE 3 S 4 NE 3 NE 2

1981 4 NE 3 S S W 5 NE 3 E 3 S n.a. n.a. n.a. n.a. n.a. n.a. 3 W 4 NE 4

1982 4 W 5 W S W 4 E 4 E 4 E 4 SE 5 SE 3 NE 4 NE 4 NE 4

19&3 4 NE 4 W 6 W 7 W 4 E 4 SE 4 SE 3 SE 4 E 4 NE 4 NE 3

1984 4 NE 4 W S S 4 E 4 E 5 E 5 S 6 SE 5 S 5 S 5 NE 5

1985 5 NE 4 NE 6 E 5 E 6 E 5 SE 5 SE 6 SE 5 SE 4 E 5 NE 4

1986 5 NNE S w 7 W 6 E 5 E 5 E 5 E 5 SE 1 E 5 NE 5 E 4

1987 4 NE 4 NE S NE 6 E 5 SE 4 E 5 SE 5 SE 4 E 4 E 4 NE 4

1988 4 NE 5 E 4 E 6 E 6 E 7 E 4 SE 5 SE 4 S 5 NE 5 NE 4

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Monthly average prevailing wind speed (knots and direction/1 knot = 0.514 m/s)

Dinajpur (1981 - 1988)

YEAR JAN FEU MAR APR' MA\' IUN JUL AUG SEP ocr NO\'

SPD DIR SPD DIR SPD DIR SPD DIR SPD DIR SPD DIR SPD DIR SPD DIR SPD DIR SPD DIR SPD DIR SPD

1981 6 NW 7 NW 8 W 8 NE 7 NE 6 NE 6 NE 6 NE 3 E 2 W 2 N 5

1982 3 NW 4 W 3 W 3 E 3 E 3 E 2 SE 3 E 2 E 2 NE 2 W 2

1983 2 NW 3 W 4 W 5 E 3 E 2 E 2 S 3 SE 3 E 3 E 2 NE 2

1984 2 W 4 W 4 W 3 E 3 E 3 E 2 E 3 E 2 SE 2 E 2 NE 2

1985 3 W 3 W 5 W 3 E 3 E 2 E 2 E 3 E 2 E 3 E 2 NE 2

1986 2 W 3 W 5 W 3 E 3 E 3 E 3 E 2 SE 2 E 2 E 2 E 2

1987 2 W 3 W 3 E 3 E 2 E 2 E 3 E 4 E 2 E 2 E 2 NE 2

1988 2 W 2 W 4 W 3 E 2 E 3 E 2 S 2 S 2 S 2 NE 3 NE 2

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0.2.2.3.5 Earthquake

General Bangladesh is historically less affected by earthquakes. During the last some one hundred years widespread damages were caused by only the Great Earthquake of 1897 which had its epicentral tract in the Shillong plateau. Two other major earthquakes, the Bengal Earthquake of 1885 and Srimangal Earthquake of 1918 caused severe damages only in limited areas surrounding their epicenters. The present geological information does not indicate existence of seismically active faults within the country. However, north and east of Bangladesh, there are areas of high seismic activity in India and Myanmar and earthquakes originating in these areas affect adjacent regions of Bangladesh.

Seismic zoning map According to the Final Report on "Seismic Zoning Map of Bangladesh and Outline of a Code for Earthquake Resistant Design of Structures (1979)", Bangladesh has been divided into three seismic zones. The Seismic Zoning Map of Bangladesh is shown in Annex. The northeastern part that includes the towns of Sylhet, Mymensingh and Rangpur are in Zone I, the most active seismic zone where earthquake shock of maximum intensity of IX of Modified Mercall Scale is possible. Zone II includes the towns of Dinajpur, Bogra, Dhaka and Chittagong. The project area is included in Zone II. The horizontal seismic coefficient = O. 15 g. Code for earthquake resistant design of structures The main aim of the code for earthquake resistant design of structures is to ensure that structures are able to respond to shocks of moderate intensities without structural damage. This code is meant only for normal buildings with height no more than 200 ft. In case of taller building, a dynamic analysis must be performed, with the ground acceleration inputs appropriate for the probable maximum intensity for particular zone. According to this code, the shear force at the base of a building is given by the following formula:

v = Z.I.K.C.S. W Where Z : Basic horizontal seismic coefficient (0.06 for Zone II)

I : Importance factor (1.5 for important facilities, 1.0 for others).

K : Structural system factor (varies 0.67 - 1.33 according to structural systems).

C : Structure flexibility factor (varies 0.20 - 1.0 according to the fundamental time period of a building)

S : Soil foundation factor (varies 1.0 - 1.5 according to the combination of soil type and foundation type)

w : Design vertical load

The maximum design horizontal seismic coefficient = 0.15 g shall be considered.

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0.2.2.3.6 Flood water level condition

The elevation of the site area is geodetically higher than the other parts of Bangladesh. Therefore, the flood damage is "less" than that of the other regions. According to the resident in the vicinity of the site area, the maximum flood level in 1988 was less than one meter above the ground level of that time. Accordingly, during construction of unit no. 1 & 2 the Plant area was filled approx. 2 m high from that ground level to protect the Plant facilities from the flood. For the flood protection, the railway is situated on an embankment which is 1.5 m to 2.0 higher than the ground level.

Therefore major earthfilling is not required. However if ground level of any area of the proposed plant is found lower, it shall have to be filled up to the level of existing plant. Underground piping and cabling shall be installed in waterproof ducts which shall be equipped with lighting and fire alarms and which shall be accessible for the maintenance staff.

Geological conditions

The stratigraphical sequence has been divided on purely litho logical grounds into the following groups:

Madhupur Clay (Recent - Pleistocene)

Dupi (Tila Formations) -Upper (Pliocene) - Lower (Pliocene- late Miocene)

Gondwana Group (Permian) - Upper Coals Sequence - Seam VI Sandstone Sequence - Seam VI - Lower Sandstone Sequence

- Tillites

Dasement (Pre-Cambrian) The outline of Madhupur Clay and Dupi Tila Formation are as follow: Bulk Density : 1.91 - 2.19 t/m3

a) Madhupur clay

The Madhupur Clay formation was found across the entire site beneath a thin soil horizon. It varies in thickness between 3 and 15 m, but is generally 10-12 m in thickness. Lithologically, the fonnation comprises series of firm and stiff silty clays interlaminated and interbedded with silts and siIty sands. The silt and sand horizons increase in frequency to the base of the formation. The geotechnical and hydrogeological characteristics of Madhupur clay are summarized as follows:

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Shear strength of Madhupur clay

Cohesion (kN/m3) Shear

Resistance Angle

Shear box test 119 14°~ 33°

Undrained multistage triaxial test 30~85 17°~ 11.6°

Permeability: 9.79 x 10 - 5 - 5 X 10 - 7 m/s Ph: 6.8 - 7.4

b) Dupi Tila formation

Dupi Tila formation is divided into two groups, the upper and the lower.

The upper Dupi Tila formation is dominated by sands between 94 m and 120 m in thickness. The lower Dupi Tila formation, which is dominated by clays, is located In the southern part of the coal deposit area and not present in the power Plant site.

The upper Dupi Tila formation, with the average thickness of 107 m is divisible into two main units:

The upper unit: average 65 m in thickness, of micaceous gray sands and gravels with occasional bands of silt and clay. The lower unit; approximately 40 m in thickness, of orangebrown, slightly micaceous sandstone, generally finer than the upper unit with more frequent thin beds of slit and clay.

The geotechnical and hydrogeological characteristics of the upper part of the upper Dupi Tila formation are summarized as follows: Bulk density: 1.92~2.00 t/m3 Shear strength of upper Dupi Tila formation

Cohesion (kN/m1) Shear Resistance

Angle

Shear box test 130 24.5°

Triaxial test

Undrained multistage 10 - 45 2° - 4°

Consolidated drained 62 2°

Unconsolidated undrained 16 27.5°

• These tests were carried out on undisturbed samples of cohesive materials such as silt or clayey silt of the Upper Dupi Tila formation.

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Permeability No permeability test has been carried out for this formation. However, the permeability of this formation is considered larger than that of Madhupur Clay, judging from its soil composition.

pH: 7.2 Topographic conditions The project area in Dinajpur district, between Phulbari and Parbatipur is situated in the deltaic plain of the Jamuna and Padma Rivers. It is flat and its altitude is about 30 m above mean sea level, which is relatively higher than the other areas of Bangladesh.

0.2.3 Layouts The detailed arrangement shall be proposed by the Contractor under consideration of easy maintenance, access, short links for piling and cabling, interfaces to the power grid. The plant area shall be developed upto existing plant level (if required). The ash pond shall be lowered below the natural ground for about 3 m and shall be provided with bud walls up to + 5 m above the natural ground. The park area shall remain at about natural ground level with the exception of the outfall canal.

0.2.4 Configuration

One coal fired boiler with turbine generators represent the core components of the Plant.

The cooling requirement of the Plant shall be accomplished by a wet cooling tower system. For ash transport, the cooling tower blow down water shall be used. But for commissioning fresh water is required.

0.2.5 General technical requirements of the Plant 0.2.5.1 Design requirements

The Plant shall be designed for base load operation. Also extended shorttime operation and longer periods of part load down to synchronized minimum load must be possible without restrictions.

The design lifetime of the Plant shall exceed 200,000 operating hours.

The thermodynamic process of the Plant is to be optimized by the Tenderer/ Contractor according to the proposed equipment.

The Plant shall be built-up of one independently operable power unit.

An economic optimal balance between investment, maintenance expenses and Plant availability (planned and unplanned outages) shall be proposed .

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Redundancy concept Due to the block-wise structure of the Plant, the Tenderer/Contractor may propose only 1 x 100% implementation of very costly major equipment like: cooling water pumps, compressors, etc., but by no means for the boiler feed water system. These moderate investment solutions can be accepted if the Tenderer/ Contractor proves with corresponding spare parts and maintenance proposals that overall an optimum economic solution will result; otherwise 3 x 50%, or 2x 100% solutions are preferable.

The Tenderer/Contractor shall

a) design and configure all components of the Plant b) propose spare parts stock (spare part building and content) c) propose maintenance works in such a way that:

• unplanned outage time of power unit shall not exceed 1.7% of the time in a calendar year

• Unit is available during 99.2% of the time in a calendar year.

0.2.5.2 Outline description of generating facilities

a) Installed capacity 250 MW Net

b) Annual utilization factor 80%

c) Overall gross efficiency 38.0% (minimum)

= output el. at Gen. terminal /input coal net calorific value

d) Plant starting scope at all conditions of warm/hot or cold.

e) Unit auxiliary consumption 6.3% (max.)

f) Annual coal consumption about 700,000 tons (approx.)

g) Ash disposal area (proposed) 3 75,000 m2

h) Design life time of the power Plant shall exceed 200,000

operating hours.

0.2.5.2 Main powerhouse including control building

The main powerhouse which includes the control complex need to be a multilevel multi-area structure. It shall be a seismic proof building of conventional steel braced frame construction in the upper portion with foundations of reinforced concrete.

0.2.5.3 Civil

The area of the Power Station for protection against flooding is considered to be

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filled up to the existing plant level (if required) to protect the Power Plant against the flood.

The coal storage area shall be paved. drained and partly covered. The drain shall be discharged to the ash pond. The ash pond shall be excavated. fertile soil to be stored aside and the pond shall be lined with clay. The ash pond overflow shall be treated to meet the relevant standards and shall lead via outfall canal to the Tillay river. Try ash storage shall be considered as an option.

The treated sewage water may be discharged to the Tillay river.

The ash pond and the park shall be separated from each other and the Plant by fences and gates.

0.2.6 Mode of operation

All the equipment and the facilities shall be suitable for safe and economical continuous and also for short-time operation under the extreme ambient air. water and coal conditions specified.

The design of the Plant shall be based on the following operation and dispatching requirements:

a) The power unit shall be capable of following the daily and seasonal demand profile of the electrical network.

b) The power generation shall be fully dispatch able within the technical limits of the Plant to be specified by the Tenderer, but at least between 40% and 100% of the net power output of the Plant without supporting fire.

c) Full compliance with the conditions of the admissible air pollution is required within 40 - 100% of power unit's power range.

0.2.7 Environmental conditions and emission control standards

0.2.7.1 Environmental conditions

The present environmental conditions in Barapukuria are as follows:

a) Atmospheric quality

There are no industrial activities to pollute air within a radius of 10 km from the planned Power Station site (except existing 2 x 125 MW coal fired units). Though there are effects of automobile, etc. emission and smoke generated by burning after harvesting and from houses, the air pollutant concentration is expected to be at a very low level.

b) Water quality

As prospective raw water sources, Coal mine discharge water (for normal use) and wells (during emergency case to meet at least 50% of total requirement) are considered. Water quality is given in Annex.

24

c) Soil quality

The study team collected the soil (in the year 1998) from the site for analysis and the results are as follows:

Analysis result of metal content in soil

MgO CaO Na20 K20 B203 Item % mg/kg Barapukuria soil

0.7 0.2 0.2 2.2 427 201

Analysis result of water dissolving and pH of soil

Item pH EC Mg1+ Ca2+ K+ Na+ B3+

µS/cm

mg/kg

Barapukuria soil 6.5 12.7 0.1 0.2 0.2 1.0 <0.1

Latest soil analysis is to be done by the Contractor/ Tenderer. 0.2.7.2 Ambient standards and emission standards

The standard values are given in Annexes. The standard values for effluent are also given in Annexes.

25

0.2.8 Fuel

0.2.8.1 Characteristic of coal

These data should be compared with new data which will be analyzed by the coal mine and examined by the personnel of the Power Plant. After having further investigation on the Barapukuria coal, the coal analysis data for the planning of the boilers at the Owner/Owner's Representativeing stages should be finalized. At the time being the proximate analysis (average characteristics of whole seam) is as follows:

Net Calorific Value 23.500 MJ/ kg Gross Calorific Value Air Dry Basis 25.540 MJ/ kg Dry Basis 26.000 MJ/ kg Total moisture Receive basis 8.20% Inner moisture Air dry basis 1.71% Fixed carbon Receive basis 46.92% Air dry basis 50.24% Dry basis 51.11% Ash Content Receive basis 17.81% Air dry basis 19.07% Dry basis 19.40% Volatile content Receive basis 27.07% Air dry basis 28.98% Dry basis 29.48% Sulfur Dry basis 0.16%

Ultimate analysis (dry ash free basis)

Carbon 83.0%

Hydrogen 5.1% Oxygen 9.4% Nitrogen 1.7% Sulfur 0.77% 99.97%

26

0.2.8.2 Ash

At the time being the following ash analysis (oxides in ash dry basis) (mean % of whole seam) is available:

Si02 54.4%

AI2O) 35.6%

Fe203 2.9%

Ti02 3.2%

Mn304 0.11%

eaO 0.56%

K20 0.66%

Na20 0.06%

MgO 0.18%

P20S 0.46%

SO3 0.13%

Ash fusion temperatures of seam Vi (mean °C) (reducing atmosphere)

Initial Deformation > l,400°C

Hemispherical > l,400°C

Flow > 1,400°C

0.2.9 Waste and waste water

Water supply of the Power Plant will be covered by Coal mine discharge water (for normal use) and deep tube well water (during emergency case to meet at least 50% of total requirement). To cope with the water requirements of Power Plant consumers it is necessary to install water treatment and storage facilities. The design of the storage facilities shall consider especially start-up and routine maintenance periods in the Power Plant and water treatment plant.

Chemical polluted wastewater and sewage wastewater has to be treated to comply with the relevant wastewater emission standards. Chemically polluted wastewater shall be discharged after treatment to the ash pond

The waste water from the ash pond shall be discharged to the Tillay river. The water which will be discharged to the Tillay river shall be treated also. This water shall be suitable to be used in the park for fountains as well as for irrigation purposes.

27

0.3 Supply and Services

0.3.2 General

The scope of this Tender Specification covers all supplies and services required for meeting the purpose of the complete Plant, even if these are not expressively mentioned in the following.

The works include the following main components, where the detailed scope of supply shall be seen in the corresponding sections as listed below:

• Section B1 : Steam Generator Plant

• Section B2 : Steam Turbine Plant with Condensate and Steam System

• Section B3 : Coal Handling System

• Section B4 : Air and Flue Gas System

• Section B5 : Ash Handling System

• Section B6 : Water Storage and Treatment Systems

• Section B7 : Auxiliary Systems

• Section B8 : Electrical and Associated Works

• Section B9 : Instrumentation and Control Works

• Section B10 : Communication, Clock and Surveillance Systems

• Section B11 : Civil Works

• Section B 12 : Workshops, Stores and Vehicles

Before purchasing of any material the documentation for each major component/system shall be approved by the Owner/Owner's Representa-tive/Owner/Owner's Representative.

0.3.2 Scope of Owner/Owner's Representativeing services

The Owner/Owner's Representativeing services of the Contract refer to the complete specified plant and covers following services:

The Contractor shall actively participate in drawing-up of all required licensing applications.

All services shall be performed by the Contractor to effect the required permits to commence the works and operate the Plant, including but not limited to:

• clarifications with authorities

• participation in all clarification meetings

• boiler operation permission by independent authority

• and all other services as required.

28

All fees required due to a split-up into multiple applications shall be covered by the Contractor.

0.3.3 Common equipment and services

The following supplies and services are to be included in the corresponding section prices.

0.3.3.1 General

• material and personnel costs (e.g. for testing authority staff, BPDB and if

necessary also Owner/Owner's Representative's staff) for tests and in-spections which are mandated by legislation

• material costs for site inspections

• declaration of conformity with Bangladesh requirements and markings for all machines

• Owner/Owner's Representativeing design of complete supplied equipment including interface coordination

• all as-built documents (on data carriers; data formats as requested by the

Owner/Owner' s Representative)

• quality control plan and safety plan

• complete documentation as set out in the tender specification

• operating and maintenance manual in summary form (8 copies), O&M manual

• detailed operating and maintenance instructions (8 copies)

• a maintenance program including a well proven maintenance management system for track keeping of all maintenance for all systems and equipment of the Plant.

0.3.3.2 Mechanical

• All necessary pipelines, valves, actuators, suitable for commissioning,

operation and standstill in preservation

• all required line warm-up systems

• all connection and adaptation works for tie-in into general supply and/or

evacuation systems

• all necessary vents, drains and rinsing connections as well as tundishes with

covers, as far as possible aggregated to common groups of on operating

level.

• all connection elements, screws, bolts, nuts, including gaskets and seals as

necessary.

• all temporary installations required for tie-in measures including postweld

heat treatment complete, inner cleaning, etc.

29

• all temporary pipework as required during connection measures

• check of required existing structures, plant components and systems and

their rehabilitation where they lie within the scope of supply, or definition of

required measures in good time if they lie outside of the scope of supply

• all support structures, hangers etc.

• all base frames, mounting plates, grouted in parts, rag bolts, covers, etc.

• all required steel parts embedded in concrete

• all couplings and coupling guards for electric motors and other drives

• all lifting equipment and hoists (for repair work where loads exceed 50 kg)

(cranes, hoists, monorails, etc.), electrically operated if lifting or lowering

heights exceed 8 m

• required safety equipment, pressure relief valves, etc.

• all thermal and noise insulation including cladding as well as any other noise

attenuation measures

• stairways, ladders, platforms, galleries and walkways to all plant compo-

nents, including escape routes as necessary

• all necessary steel structures, stairs, ladders on platforms weather protec-

tion

• all required ventilation or air conditioning equipment for safe operation of

mechanical and electrical equipment, to be supplied

• all necessary corrosion protection measures for plant components and

equipment stored or mounted on site up to the time of reliability test run

• complete primer and top coatings conforming to color code, clarified with

the Owner/Owner's Representative/Owner/Owner's Representative

• noise abatements measures

• all corrosion protection and electric trace heating for outdoor installations

(e.g. gas ducts, etc.)

• complete labeling of all plant components according to the Owner/Owner's

Representatives system and in plain language (English and Bangla) and

Power Plant Classification System Coding (PPCS)

• all fire protection measures

• all lubrication systems

• initial lubricant filling and sufficient lubricants for commissioning and reliability

test run, minimization of lubricant types by screening and coordination with

the Owner/Owner's Representative, up to Provisional Taking Over of the

relevant Unit

• provision of all connections and temporary pipe work for steam purging of the

live steam line

• flushing of all other lines including disposal of the effluents; protection with

30

wood and/or plastic at all instrumentation and appendages to be installed

during construction

• all standard accessories and auxiliary equipment which normally form part of

the scope of supplies

• all tests, inspections and works acceptances as well as all certificates and

reports of these

• exchange of filter elements following reliability test run up to Provisional

Taking Over of the relevant Unit

• valve trims for purging and subsequent exchange

• removal of any unused material from site

• scaffolding for all work aboveground level

• insurances.

0.3.3.3 Electrical, instrumentation and control

In general, the Power Plant shall be started up, operated and switched down from the DCS.

The electrical instrumentation and control plant mainly, but not limited to, shall consist of:

all local measurements and field control loops (thermometers, pressure gauges, local regulating devices, etc.) as well as all instruments for reliability test and checks.

• all necessary electrical drives

• complete installation material, that is wiring, cabling and piping mate-

rial, all needed fastenings, conduits, brackets and other supports, in-

cluding the cable trays

• all required junction boxes and cubicles

• all field control boxes.

• all instruments mounted on instrumentation racks

• street and other outdoor lighting

• lightning protection

• electrical earthling of the equipment

• clarification of all logic interconnections: sequence, interlocking, protection,

safeguarding for coordinated operation start-up/shut down of individual items

of equipment.

0.3.3.4 Civil

• Soil investigations

31

• all necessary surveying works

• preparation of site, demolition works, removal of underground obstacles, if

any

• site fill

• earthworks, drainage, excavation and refilling works

• roads and pavement

• concrete and reinforced concrete works, masonry and earthing

• water proofing works for pressing and non-pressing water

• fire protection during construction

• roofing (non asbestos)

• plumbing

• facade works/glazing works; non asbestos

• non-load bearing walls/installation partitions/dry construction works

• metalwork and blacksmith work/raised flooring/doors and gates/sheet

metalwork

• flooring work

• fire protection with plumbing; fire protector

• corrosion protection

• crane way works

• air conditioning systems

• potable water, service water and waste water, sewage water, storm water

(permanent and during construction), etc.

• housekeeping during construction.(at least once a week total)

• staff facilities during construction

• Owner/Owner's Representatives office

• transport of all dumping material to dump locations (at least once a week

total)

• interpretation of soil bearing test

• temporary fencing of construction site

• permanent wall and fencing with security road

0.3.4 Packing and transportation

• Suitable packaging and transportation of the entire scope of supplies

• free construction site, on-site transportation and temporary storage

including inspections and, if necessary, ensuring the prerequisites for

transportation

• transport insurance

32

• disposal of packing and transportation material

• customs clearance

• crane or hoisting facilities at seaport, railway, road and site

• transportation to site

• unloading at site

• transportation to the place of installation.

0.3.5 Documentation 0.3.5.1 Documentation with Tender

General

• form of Tender (Data Sheets) to be completed by the Bidder

• deviations from the Tender Specifications on data sheet B0/FA

• if a consortial bid is submitted, documents on the consortial agreement

• description of options and alternatives offered

• completely filled in price, guarantee- and data sheets of the

specifications

• list of proposed makes and vendors

• reference lists for delivery and installation of plants of similar type and size

• time schedule for Owner/Owner's Representativeing, deliveries,

erection/installation, commissioning and Reliability Test Run

• complete description of the plant offered including description of the

process and the equipment

• layout drawings of the plant

• dimensioned drawings and sectional views of the principal plant

components

• schematics of the principal plant systems

• general descriptions of individual systems and descriptions of

operation including description of start-up, shutdown and emergency

shutdown procedures, tendencies showing the behaviour of

boiler/steam generator, turbine, etc.

• all other documents necessary for comprehension of the offered

plants and equipment

• documents on the quality assurance system

• training program and schedule for Owner/Owner's Representative's

personnel.

• space requirement for construction site and equipment

• maintenance proposal (section 0.3.9) with list of tools and appliances

33

• lists of spare parts for warranty period, lists of spare parts for LTSA

period

• spare part storage and supply policy

• mobilization and demobilization schedule for construction equipment

• method of transportation and unloading heavy cargo

Mechanical

• flow diagram of all systems

• performance diagrams of main pumps, compressors, fans, etc

• start-up curves for cold (all material on ambient temperature) and warm start

up to MCR of one Unit

Steam turbine and boiler

• correction curves for variations in

• power output with normal water temperature and pressure

• part load chart

Generator

Detailed descriptions/references of the main components such as:

• stator and rotor design

• excitation equipment

• cooling system

• power chart (generator capability curve MW, MVAr, p.f.)

• no load and short circuit characteristic

Boiler

Description for the equipment offered giving information about:

• general outline of installation

• extent of shop fabrication

• indicating site fabrication required

• ducting including expansion joints

• insulation, as well as anchors and sheets and refractory

• spray attemporator and its characteristic

• mounting, valves and fittings, including all safety valves.

• description of equipment for other control system, if applicable

• NOx, CO, S02, etc. emission characteristic for coal operation versus load at

full load

34

• Drawings

• dimensioned general arrangement of boilers, turbines, ash extraction, pumps, fans, el. precipitator, mills, conveyors, transportation, etc. ducting including guide vanes and expansion joints, damper, isolator, platforms, stairs, ladders and stack, workshops, chemical laboratory , stores, administration building, entrance, fence and all other structures

• dimensioned front and side sectional elevations and sectional plan of the boiler, turbo group, showing drum, casing, insulation, access and observation doors and all tube banks and all accessories (conveyors, breakers, etc., all boiler pressure parts, turbine/generator details, mill, ash extractor, ash transportation, etc.

• design of the membrane walls and supporting by buckstag

• Graphs, correction curves for boiler

• tentative start-up diagrams for cold start, warm start and hot start

• material diagram showing material, dimensions, highest exhaust gas

temperature and highest steam temperature, design material temperature

and maximum admissible material temperature and design pressure for

components of the steam/water system

• change of exhaust gas temperatures over load

• variation of steam temperatures over the heating surfaces, stating ma-

terials employed

Electrical system

• electrical single-line diagram

• preliminary lists of motors and electrical consumers including power demand

• auxiliary power requirement of the plants

• arrangement of generator bus duct up to generator step-up transformer, HV

and star-point cubicles, unit auxiliary transformer

• general arrangement of electrical equipment

• I&C power supply ,

• description of the power supply system for DC/AC systems(24 V DC

and/or 230 V AC, redundancy, failure management, etc.)

• DC and safe AC supply principles

• detailed explanations to be given for the DC and safe AC principle to be

provided

• construction power supply arrangement

• general arrangement of 230 kV switchyard equipment

Instrumentation & Control system

• control system architecture showing all components provided for this Power

35

Plant in their structural arrangement

• description of philosophy of the DCS with reference to

• availability

• redundancy concept

• description of burner management and boiler protection system including

information about redundancy concept .

• list of all subcontractors

• reference list for the DCS with indication of plant type, system architecture

and size of the system

• list of package system (black boxes)

Civil

• architectural outline drawings for all buildings and building structures showing the arrangement of the complete plans, inclusive of all levels and sections

• site plan of the complete plant showing all buildings, building elements, roads, landscaping etc .

• schematic design of building

Maintenance

For boiler with accessories, steam turbine, generator and the total scope of supply maintenance and overhaul charts should be submitted. Both major and minor plant outages for inspection and/ or routine maintenance should be shown on the chart, together with the nature of the work to be undertaken and the expected duration of the outage. This information should also include all the auxiliary plant to be supplied under the Contract.

0.3.5.2 Documentation after award of Contract

The documents required for design, construction, installation, operation and maintenance of the entire plant shall be submitted by the Contractor in good time so as to permit the plant as a whole to be erected in compliance with the specified time table.

Only the most important documents are listed below. These documents shall be submitted sufficiently in advance for approval before award of relevant order, so that corrections and amendments desired by the Owner/Owner's Representative as well as resubmission of the documents will not result in any delays with respect to the guaranteed time table. The Owner/Owner's Representative reserves the right to request from the Contractor additional drawings, documents, etc. as may be required for proper understanding and definition of the design and Owner/Owner's Representativeing of the Plant.

General

• current list of drawings (to be updated every month)

• progress reports (to be updated every month)

36

• erection and installation progress reports (to be updated every month)

• list of subcontractors/manufacturers for approval before purchasing

• proposed inspection and testing programs for approval

• detailed program for commissioning for approval

• testing documents/report of results of all tests for approval

• training program for approval

• operating and maintenance manual with description and instructions for all

equipment and facilities (first issue 3 months before start of commissioning

and second issue before trial run (2 weeks) - OMM for approval

• as-built-documentation including drawings of all equipment

• declaration of conformance with Bangladesh regulations

• spare part lists for approval

Time scheduling, based on CPM

• overall time schedule for design, manufacture, supply, assembly and II

commissioning broken down for the principal plant components and all

construction works, stating dates for completion of any preparatory work from

others which may be necessary.

• detailed erection, installation and commissioning schedule

• complete list of documents with proposed submission deadlines

Mechanical Owner/Owner's Representativeing; such as, but not limited

to:

• arrangement drawings of the principal components with ducts and platforms

layouts .

• arrangement drawings of all auxiliary equipment (cubicles, etc.) and ancillaries

• piping and instrumentation schematics and isometric drawings, including lists

of pipelines and valves stating materials, )nominal diameters, nominal

pressures, dimensions and insulation thickness of all pipes;

• plans of main pipelines including location of cable routes

• characteristics of pumps, fans, etc.

• details of required auxiliary energy sources and consumer consumables (e.g.

electricity, steam, chemicals, instrumentation air, working air) with condition

data and consumption values

• thermodynamic diagrams

• start-up and shutdown diagrams with descriptions

• welding procedures (for workshop and site), to be approved before execution

of the welding

37

• sectional and detail drawings of all components

• for all lifting operations (repair, maintenance, etc.) a lifting plan has to be

submitted by the Contractor

• limits of coal and fuel oil properties

Boiler and accessories

• start-up charts from cold

• start-up charts from warm

• start-up charts from hot

• general arrangement and section drawing of the casing, stack, etc.

• detailed arrangement drawings of all equipment including all auxiliary

equipment (flash tank, etc.) complete with pipes, cable tracing, steel

structures, cubicles, electric consumers, etc.

• drawings and information for all relevant components such as

• dimensioned details of drums and internals

• boiler and ducting support and expansion joints

• tube bank support details

• list of insulation materials, showing type, location, protection, fastening

and surface temperature

• boiler through flow schematics stating materials, temperatures etc.

• graph of controlled and uncontrolled super heater steam temperature

• diagrams, correction curves and drawings as well as p+i diagrams, etc

Electrical Engineering (Power Plant and 230 kV switchyard)

• electrical single-line diagrams

• list of motors and consumers

• electric motors

• starting curves (torque of motor and driven machine, time, speed) for all

motors of 50 k W and more

• cable lists

• standard circuit diagrams for all different kinds of electrical consumers

• circuit diagrams for all individual electrical equipment

• lists of equipment and devices

• alarm lists and lists of measuring points

• earthing plans with calculations

• lightning protection plans with details of measuring locations and reports of

measurements taken following commissioning

• EMC concept with coordinated over voltage protection (NEMP level is not

38

required)

• arrangement drawings of all electrical equipment

• line plans of fire alarm system if applicable

• arrangement drawings showing exact location of fire alarm devices if

applicable

• power and lighting installation plans

• earthing and lightning protection plans and calculations

• general arrangement drawings of the required cable trays, cable laying plans

• dimensioned drawings and erection drawings for generator, transformers,

switchgear, control panels, etc., including frontal and plan views

• dimensioned drawings of generator auxiliary equipment

• dimensioned drawings of switching cubicles, generator and star point

cubicles, voltage regulation cubicles, excitation cubicles etc., including

equipment configurations

• calculation of mechanical stresses of switchgear rooms due to arcing faults

• short circuit calculation and determination of protection relay settings for

generator protection and auxiliary electrical supplies under consideration

of protection of the entire system .

• overall protection and metering diagrams for the whole protection equipment

• generator charts and exciter characteristics

Construction power line (33 kV)

Contractor will use Construction Power from the existing 33 kV substation. All

arrangements shall have to be done by Contractor.

Instrumentation and Control

• list of subcontractors

• list of the overall- I&C equipment

• list of spar parts

• list of "black box" systems with indication of control systems to be used

• schedule of workshop tests

• manufacturer documents (manual, descriptions, etc.) for all I&C components

• manuals for third party computer software

• set of all relevant standard specifications to which the equipment is

manufactured

• list of instruments including code, measuring range, alarm and limit values,

reference drawings

• instrument location plans

39

• instrument hook-up drawings

• list of control valves including operating and design data, materials, makes,

types and reference drawings .

• calculations for control valves, orifices, nozzles, etc.

• Owner/Owner's Representativeing drawings of control valves (including

actuators), control dampers (including actuators), orifices, nozzles, venturi

nozzles

• diagram of control system architecture showing all components provided for

this Power Plant in their structural arrangement

• lists of I/O point assignment

• list of alarms including settings

• program listings for all application programs

• logic diagrams

• description for all functional group controls

• description for all closed loop circuits

• description for all safety and protection circuits

• instrument loop diagrams

• typical cabling diagram showing all cable connections in a typical manner

• cable list including cable coding

• cable routing plans

• interior arrangement drawings of all cubicles

• wiring and terminal diagrams for the entire I&C equipment

• arrangement drawings of central and local control/electronic rooms

• mimic diagrams for control panels and desks

• detailed dimensions of panels, desks and cubicles

• list of recorders

• graphic displays for monitors of options.

Civil Owner/Owner's Representativeing

• general site plan of the entire site showing all buildings and installations,

traffic routes and landscaping etc.

• architectural arrangement drawings, design layouts and itemized drawings

(plans and sections) to scale 1: 1 00 of all buildings and plants

• views of all sides of all buildings, scale 1: 100

• architectural drawings of each floor (plants, sections) including all necessary

detail drawings, scale 1 :50

• arrangement drawings of the external plants of the site as a whole (existing,

planned) with all supply and disposal facilities, roads and vehicle access and

maneuvering areas, sewers, channels and culverts etc.

40

• detailed constructive description of the single building with regard to the

structural design (structural systems, foundations etc.

• detailed specification of the buildings including information on materials and

qualities for execution

• sectional elevations and roof plan

• floating floors/systems

• underground services and ducts with equipment appertaining to the services

• layout of roads

• principal details and sections for traffic areas, especially for ramps and

retaining walls

• layouts for external works showing plants and fencing etc.

• diagrams for ventilations

• diagrams for supply systems of all buildings

• schematic details for plumbing

• structural drawings pertaining to outlet and inlet water channels and tie-in to

existing channels

• foundations and other underground concrete works for the transformer area

• civil drawings of roads and if applicable for up rated bridge over cooling water

outlet channel. Especially for Workshops, Stores, and Laboratory:

Designation Preliminary

In weeks

Final

In weeks

• Room sheets for all workshops, stores

and offices

19 23

• Requirements Documents describing

the inventory computer program and

the maintenance program from the

users' point of view

19 23

• Program Specification i.e. a complete

verbal description of the inventory

program with logic diagrams

29 33

• Test Plan and Procedures Documents

describing how the inventory program

is to be tested

39

• Complete user manuals describing

how the user will run the program

- 78

41

• Handbook of the computer program -

• language for managerial activities

• Description of equipment suitable for - • instructing computer operators

• All documentation suitable for

maintenance of the complete Power

Plant equipment by the plant personnel

without any help of the manufacturer's

staff

- 65

• Preventive maintenance schedules 65 20

after availability

of maintenance

instructions of

the corresponding

suppliers

• All documentation necessary for

ordering - 87

• Each and every spare part which may

be

• necessary during the lifetime of the

Power

• Plant down to IC, transistors, etc.

• Proposal for first outfit with raw

materials 29 43

• Spare parts list 17 23

• List of all machines, apparatus and

other - 39

• equipment for workshops, stores and

vehicles with manufacturer's name and

ad dress, equipment type and

classification code

• Stock-keeping lists (including spare

part lists containing requisition

numbers, consumables, etc.

26

before provisional

taking over

2

before provisional

taking over

42

• Maintenance assembly and adjustment

drawings - 4

before provisional

taking over

• As-built drawings - at provisional

taking over

0.3.5.3 Requirements for documentation

Unless agreed otherwise, six (6) hard copies and three (3) sets of electronic copies of all documents are to be submitted in English language for approval.

There shall be no installation and/or any commissioning activity without the relevant documentation approved by the Owner/Owner's Representative.

The final documentation shall be submitted in English language.

Diagrammatic symbols for electrical drawings

Diagrammatic symbols complying with IEC 27, 34, 37 and 117 are to be used for selling out the circuit and terminal layout.

0.3.6 Erection, commissioning and testing

• Complete erection' of the total scope of supply up to operational readiness. This includes mobilization and provision of the required supervisory staff, skilled and unskilled personnel, as well as of installation scaffolding, cranes, hoists, equipment and materials, personnel accommodation, prescribed tests and inspections

• commissioning and optimization of all plant components as well as conducting all necessary measurements

• supervision of erection, commissioning and Reliability Test Run of complete supplied equipment

• all testing as specified

• operation, training of the Owner/Owner's Representative's staff and maintenance up to Provisional Taking Over of the relevant Unit.

0.3.7 Training of Owner/Owner's Representative's personnel

0.3.7.1 General

During erection, commissioning and Reliability Test Run, the Owner/Owner's Representative's operating staff is to be familiarized with the functions of the system. In the training schedule, prior instruction of selected members of staff shall be taken into account.

0.3.7.2 Training in the Contractor's country

The Contractor(s) shall train the Owner/Owner's Representative's operation personnel on a power plant in operation, and at least in one major overhaul, of similar technique (with reheat) and unit capacity and shall arrange the relevant

43

agreement with the Owner/Owner's Representative/utility company of the power plant in question. During training period one supervisory person from BPDB headquarter should meet the trainees and review the progress in training.

In addition, the Contractor shall train the Owner's fire fighting personnel on the premises/training centre of the subcontractor for the fire fighting equipment.

The contract price shall include the following expense for twenty one (21) persons delegated by the Owner for total 100 person month:

• the cost of return air tickets (economy class) from Bangladesh to the country

where the plant/fire fighting training centre is located

• the cost of local transportation during the entire period

• the cost of full board accommodation

• the cost of special insurance as may be required

• daily allowance at the rate of one hundred (100) US$.

The training shall be performed in the English language. Approval to detailed training program shall be obtained from Owner before selection of trainees. Sufficient handout and course materials in English shall be furnished to each trainee so that he can use them as reference material after his return to Plant..

0.3.7.3 Class Room Training at site

• The Contractor shall during construction, erection, testing and commissioning of the Power Plant carry out comprehensive class room and on spot training of the operation and maintenance personnel appointed by the Owner for the Plant. 80% of the time shall be class room training, 20 % shall be on spot training.

• The Contractor shall submit a detailed training program subject to the Owner/Owner/Owner’s Representative's approval. This program shall include a time schedule showing the duration of the individual lectures for the various subjects and shall give descriptions of the single lecture subjects.

• The Contractor shall, for a number of approximately eighty (80) trainees, provide all necessary instruction material such as manuals, booklets, pamphlets, drawings, sketches, models, static cutaway models, pictures, photos, colour slides, films, projectors, etc. This instruction material shall be in English language and become the property of the Owner.

• All efforts shall be exercised by the Contractor to operate the Plant by the Owner's operation personnel under the Contractor's supervision and guidance.

• The Contractor shall furthermore advise the Owner's personnel in trouble shooting and remedying of faults.

• The instructors shall be capable of speaking and writing fluent English. These instructors must have previous experience of providing training to a third country having mother tongue other than English,

Before Provisional Taking Over, the Contractor has to demonstrate the success of the trainees by demonstrating their ability to operate the Unit. The Owner/Owner's representative has the right to refuse the trainers in case of non-adequacy with the job requirements.

44

0.3.8 Spare parts, tools, appliances, and consumable

0.3.8.1 Spare parts

Spares as well as wear-and-tear parts shall cover those parts recommended by the Contractor to enable the Plant to be operated for 05 years LTSA period after completion of the guarantee time (final take-over). These parts shall be offered on separate sheets.

Each spare part shall be labeled with its PPCS number.

All items shown in these schedules shall form part of the contract price and the Owner/Owner's Representative may order all or any of the parts at his discretion and adjust the contract price accordingly.

All spare parts required for testing of the Plant according to "Inspection and Testing" and for all action before Provisional Taking Over Certificate form part of the principal scope of supply and are not to be included in the spare parts list. They shall be included in the scope of the relevant machinery without pricing, it means for the time of commissioning, the trial operation and provisional take-over.

All spare parts required for warranty period (24 months) shall be supplied by the Contractor.

Major items of spare parts must be priced individually but minor items can be grouped together. The spare part shall be offered on separate price sheets.

The Contractor shall segregate in the schedule those "consumable" spares necessary for the efficient day to day maintenance of any items of Plant, those "spare parts" to be replaced after certain running time and those "strategic" spares which, in his opinion the Owner/Owner's Representative should hold to minimize the outage of the Plant due to breakdown.

Each item shall be labeled in BangIa and English as well as with PPCS coding system and be separately packed against damage and sealed to prevent deterioration from corrosion in a dry weatherproof building.

The spare parts shall be placed in bins, racks, drawers, shelves, cabinets, etc. to be provided by the Contractor.

The Contractor shall not use any of the spare parts without written permission from the Owner/Owner's Representative. The Contractor shall deliver the spare parts for a 24-h-MCR-operation period of five (05) years LTSA. The stores shall be suitable for these conditions.

0.3.8.2 Tools and appliances

The following tools and appliances shall be supplied under this Contract for use by the Owner/Owner's Representative: ..

a) two sets of special tools and gauges required for the maintenance c1f the Plant b) one set of special lifting and handling appliances required for the

45

maintenance of the Plant.

Each tool or appliance is to be clearly marked with its size �and/or purpose.

The tools and appliances supplied shall not be used for erection purposes by the Contractor and shall be handed over in brand new condition.

The exception to this is the special lifting gear which may be used provided that when it is handed over to the Owner/Owner's Representative it has not� been subjected to more than normal wear and is still fully suitable for its intended use.

Each set of tools and appliances under category (a) shall be suitably arranged in fitted boxes of mild steel construction, the number of boxes being determined in relation to the layout of the plant and equipment in question. If the weight of any box and its contents should be such that it cannot conveniently be carried, it shall be supported on steerable rubber-tyred wheels.

Each cabinet and box shall be painted, fitted with a lock and clearly marked in white letters with the name of the item of equipment for which the tools and appliances contained are intended.

Suitable storage racks shall be provided for all portable lifting tackle in this contract.

Suitable lifting lugs, ears or ring bolts, or tapped holes for lifting rings shall be provided on all equipment items where the weight exceeds 15 kg.

All lifting tackle shall be stamped with a unique identification number and safe working load. A test certificate from an approved Authority shall be supplied for each item of lifting tackle.

The Contractor shall provide a schedule of all lifting tackle and tools and appliances being supplied, for the approval of the Owner/Owner's Representative.

The Contractor shall provide all runway beams, trolleys, lifting blocks, special slings etc. necessary for the safe and efficient handling and maintenance of the works. Particular attention shall be paid to high level equipment such as deaerator. Electrically operated hoists and runway trolleys shall be provided for all lifts in excess of 2.5 tons.

The tools and appliances with the appropriate storage racks, cabinets and boxes shall be handed over to the Owner/Owner's Representative at the time of taking over.

Where the Contract includes site erection, any special tools or appliances required solely for erection shall be provided by the Contractor for his own use and shall remain the property of the Contractor.

0.3.8.3 Consumables

Lubricants and greases

All lubricants proposed for the Plant operation shall be suitable for all operating

46

and environmental conditions that will be met on site.

All oils and greases shall where possible be readily available in the country of installation.

The number of oils and greases shall be kept to a minimum. For each type and grade of lubricant recommended the Contractor shall list at least three equivalent lubricants manufactured by alternative companies.

The Contractor shall supply the first fill of lubricants for the Plant, and shall provide at the provisional Taking Over sufficient lubricants and greases necessary for the efficient operation and maintenance of the Plant at full load 24 hours per day for a period of 24 months (Warranty period).

The Contractor shall also supply lubricants and greases necessary for the efficient operation and maintenance of the Plant at full load 24 hours per day for 05 years LTSA period after final take over.

Chemicals and other consumables

The contract includes the provision of all chemicals, reagents, resins, and other consumables required for testing, commissioning and setting to work of each section of the Works.

The Contractor shall provide all chemicals, and other consumables required for the efficient operation and maintenance of the plant at full load 24 hours per day for a period of 24 months for each section of the works from the date of the provisional Taking Over.

The Contractor shall prepare a list of these consumables giving quantities necessary for each section of the works and the recommended suppliers.

The Contractor shall deliver to site sufficient quantities of consumables in his supply to allow for running of the Works prior to the issue of the Temporary Taking Over Certificate. The delivery of the remainder of the consumables shall be programmed to suit the operational requirements and space availability within the various stores.

The Contractor shall also provide all chemicals, and other consumables required for the efficient operation and maintenance of the plant at full load 24 hours per day for 05 years LTSA period after final take over.

0.3.9 Maintenance works

Deleted

0.3.10 Options

Deleted

47

0.4 Interfaces

0.4.1 Limits of supply

The interfaces for the Plant shall be as follows; all mentioned equipment, connections, connection materials, counter flanges, shut-off valves, safety valves are included in the scope of supply:

• fuel

Interface with the coal conveyor of existing 2x125 MW plant.

One separate coal conveyor belt with 02 nos. of coal crusher unit from the upstream of existing coal crusher unit upto new coal yard shall have to be installed by modifying coal conveyor system.

Another coal conveyor belt shall have to be installed from new coal yard to old coal yard.

One coal processing Plant (Sorter machine) shall have to be installed at the down stream of Weighing scale of Coal mine by modifying coal conveyor system.

• 230 kV switchyard

Interface with BPDB existing substation.

Auxiliaries:

• auxiliary switchgear busbars (400 V, DC system and safe AC system) for future extension by the required number of feeders

• terminal cubicles of status and protection signals for extension and interfacing of signals of future diameter extensions

• instrumentation and control

Interface with 230 kV public grid:

For SCADA data exchange V24/28 interface at switchyard and (control room).

For protection and telephony at terminal racks within 230 kV switchyard control building

• communication systems

PABX cubicle within Power Plant control building

• raw water, potable industrial, cooling water

Coal mine discharge water will be the source of raw water, potable industrial, cooling water. Proper chemical treatment is required. Deep well water will be used as backup. Deep wells having capacity 50% of

48

required quantity shall have to be installed. Interface with Coal mine discharge water and interconnection with existing deep well system are required.

• sanitary waste water Interface out fall canal (including)

• waste water, cooling tower blow down ash pond water

After reuse for ash transportation up to the ash pond

After suitable treatment at irrigation nozzles or outlet into the Tillay river

• diesel fuel oil for boiler start-up, emergency diesel generator and fire fighting pump diesel

Interface at unloading station

0.4.2 Interfaces to project facilities on site

• interfaces to existing

facilities on site roads and

railways to the Plant site

All refurbishment and adequate rerouting of connecting roads and railways to the Plant site in such a way that all material required for construction, commissioning and operation of the Pant can be delivered to site

0.4.3 Metering

Sufficient metering devices shall be provided to enable an energetic balancing of the power units and additionally to enable balancing of all process flows.

Metering of electrical signals is indicated in Annex C-B8-2, and frequency, voltage, active power, reactive power, and energy shall be metered for each power unit at the switchyard.

The accuracy and signal interface requirements for metering devices shall be according to the Metering Code (which will be submitted by the Owner/Owner's Representative during contract execution).

0.4.4 Communication systems

All communication to other subsystems and the plant systems shall be through standardized interfaces.

CCTV shall be interfaced to the Power Plant's fire alarm system. CCTV shall be provided with standard interfaces like RS-485/RS-232/ V-14/V-11.

49

0.5 Formsheets (Data Sheets)

Declaration by Bidder

(Form, to be completed by the Bidder)

B0/F-1

Deviation from Tender Document (Form, to be completed by the Bidder)

B0/FA-1

Design Data B0/FD-1

Guarantees B0/FG-1 to 14

Price Sheets (In Part A)

Time Schedule B0/FZ-l

50

BPDB. Barapukuria Power Plant 250 MW Bidder/Contractor

Section B0: General Specification



for

BPDB. Barapukurla Power Plant

It is hereby confirmed that this Bid complies in full with the Tender Document. Deviations are listed in detail in the appended data sheet B0/FA. Should this Bid be successful, beside the offered and agreed deviations all of the conditions and stipulations of the Invitation for Bid for 250 MW Barapukuria Coal Fired Power Station Project will be accepted.

Bidder: ____________________________

Bid Number: ________________________

__________________________ Stamp and Signature of Bidder:

B0/F-1

51

BPDB, Barapukuria Power Plant 250 MW Bidder/Contractor


Deviation from render Documents

'.

-

B0/FA-1

52


Section B0: General. Specification

Design Data - List of Major Equipment and Service Suppliers

Unit Data

(to be completed by the Bidder)

• Steam generator

• Steam turbine

• Steam turbine Generator

• Feed pumps, Cooling water pumps, Condensate Pumps, fire fighting pumps

• Switchgear, Switchyard, Transformers

• Distributed control system

• Construction

• Maintenance

• Civil Contractor -

• Compressor Station

• Emergency diesel

B0/FD-1

53

Guarantee Schedule

BPDB, Barapukuria Power Plant 250 MW

Section B0: General. Specification Unit Guarantees, to be completed by the Bidder

Net Power Output, Po

kW

Net Heat Rate: Net heat rate based on net calorific value of fuel at site condition (350 C, 1.013 bar, 98% RH)

kJ/ kWh at 100% Load (H100% )

at 75% Load (H75%)

at 50% Load (H50%)

Date of Completion of ICO: From Effective date of Contract, Initial Commercial Operation shall be completed within

Days

Cold startup(from ambient temp.) starting time: Time required from start command to 3000 rpm

Hours

Warm startup(after 8 hours shutdown) starting time:

Time required from start command to 3000 rpm

Hours

Hot startup (after 2 hours shutdown) starting time: Time required from start command to 3000 rpm

Hours

Cold startup(from ambient temp.) loading time: Time required from synchronization to reach full load

Hours

Warm startup(after 8 hours shutdown) loading time: Time required from synchronization to reach full load

Hours

Hot startup (after 2 hours shutdown) loading time: Time required from synchronization to reach full load

Hours

Performance Correction Curves Characteristic Curves which are necessary for correcting Net Power Output, Net Heat rate from the ambient condition to the Guarantee reference condition shall be furnished by the Bidder.

Definition of “Net Power Output” and “Net Heat Rate” are mentioned in General condition, Tender Document Part A.

B0/FG-1

54

BPDB, Barapukuria Power Plant 250 MW Minimum Requirements

Section B0: General. Specification

Guarantees, to be completed by the Bidder Unit Data

General Guarantees

The Works conform to the Specification and shall be free from defects in design, Owner/Owner's Representativeing, materials, construction and workmanship.

The. Plant furnished hereunder, and all materials, equipment, tools and supplies incorporated therein or becoming a part of the supply shall be new, unused and shall be fully suitable for the intended use, and shall meet all of the performance requirements set forth in the Contract.

The Plant shall be fully suitable for use of the specified fuel.

The Plant and all portions thereof shall be suitably coordinated as to functions and interrelations, properly responsive to controls and sufficiently stable in operation to avoid objectionable fluctuations in operating temperatures, pressures, rates of flow and the like during all stages of operation.

Warrantee period

year

2

B0/FG-2

55




Guarantee Data

Data to be guaranteed for the whole load range and complete range of ambient conditions

Absence of excessive vibration during operation of the turbine generator. Maximum effective vibration velocity measured at bearing housings:

Maximum vibration of components: (vibration criteria as per guide line ISO 10816) . -

"good", according to VDI rule 2056

Maximum noise pressure level at 1 m distance from the noise source

dB{A) 85

Maximum noise pressure level within workshops dB{A) 75

Maximum noise pressure level within central control room dB{A) 55

Maximum noise pressure at the boundary of the plant dB{A) 60

Maximum heat losses of insulation W/m2 200

(Maximum residual oxygen content in the condensate down-stream condenser and feed water downstream feed water tank within the load range 25% to 100%

mg/l 0.02

Guarantees and tolerance values of generator, transformers and electrical equipment

- to be in accordance with IEC regulations

Maximum continuous boiler steam output % 104 of turbine MCR flow

Steam temperature at superheater outlet °c 535

Steam temperature at reheater outlet °c 535

Constant steam temperature turndown range for the superheater

%of MCR 60 -100

Constant steam temperature turndown range for the

reheater % of MCR 70 -100

Minimum permissible load % of MCR 30

Output of make-up water plant m3/h

Maximum fresh water demand from deep wells m3/h

B0/FG-3

56




Guarantee Conditions

Fuel coal net calorific value (LHV) kJ/kg 23,500 Fuel coal Gross calorific value (HHV) kJ/kg 25,560 Ambient air temperature (dry bulb) °C 26 Relative humidity % 70 Power factor - 0.85 Maximum temperature rise in generator windings according to IEC 34.1, Class B

-

Correction curves for deviations in operating conditions, drwg. Nos

-

Electrostatic precipitator efficiency on the basis of the specified coal

% 99.5

Condition A: Maximum Continuous Rating Live steam flow kg/s Live steam pressure at boiler outlet bar Live steam temperature at boiler outlet °C Reheat steam temperature at boiler outlet °C Cooling water flow kg/s Cooling water temperature at cooling tower outlet °C

Gross output (at generator termional) MW Gross specific heat consumption (qgrA) kJ/kWh

Swallowing capacity at steam turbine (100% live steam pressure)

kg/s

Condition B: 75% Load Operation Live steam flow kg/s Live steam pressure at boiler outlet bar Live steam temperature at boiler outlet °C Reheat steam temperature at boiler outlet °C

Gross output (at generator termional) MW Gross specific heat consumption (qgrA) kJ/kWh

B0/FG-4

57




Condition C: 50% Load Operation

Live steam now kg/s

Live steam pressure at boiler outlet bar

Live steam temperature at boiler outlet °C

Reheat steam temperature at boiler outlet °C

Gross output (at generator termional) MW

Gross specific heat consumption (qgrA) kJ/kWh

Total auxiliary consumption including generator excitation power and transformer losses at MCR operation (Condition A)

MW

Total auxiliary consumption (excluding generator excitation power and transformer losses) at MCR operation (Condition A)

MW

List of detailed auxiliary consumers

Drwg.No.

B0/FG-5

58

B0/FG-7




Steam turbine plant

Maximum increase in running speed of turbines in case of sudden full load reduction % 8

Drop in steam turbine condenser vacuum at closed air suction I mbar/min valves at pure condensing operation

mbar/min less than 1.5

Boiler running time between inspections

Within this period, it shall be possible to continuously operate the boiler at MCR with the guaranteed steam conditions without the need to stop the steam generator for cleaning on the flue gas side. Normal cleaning of the surfaces has to be executed with the installed cleaning devices at a maximum of 3 cycles in 24 hours (continuous blowing is not permitted).

It is presumed that the boiler is operated in accordance with the operating instruction.

The necessity for terminating the boiler running time will arise if there is:

• a rise in the correct flue gas temperature at the regenerative air preheater outlet of greater than 20 K or

• a rise in the pressure loss on the flue gas side up to the regenerative air preheater outlet of greater than 20% or

• the design temperature of the superheater or reheater material at any location is exceeded.

If the guaranteed boiler running time of 8,000 h cannot be fulfilled, improvements remedy of defects have to be executed and after these the full running time test has to be started again.

Emissions

At all loads and operating conditions of the steam generator with coal" firing following emission limits shall not be exceeded, measured In the chimney:

h

8,000

• Nitrogenoxides (NOx) of the flue gases, calculated as N02 (stp, dry, 5% O2)

mg/m3

• Carbonoxid (CO) of the flue gases (stp, dry, 5% O2) mg/m3 • content of solid particles in the flue gas (stp, dry, 5% O2)

leaving the EP mg/m3

CO2 drop (dry) between combustion chamber and regenerative air preheater outlet at MCR

%

59



Guarantees Unit Data

Wear and tear parts

Coal mills h 12,000

Pulverized coal operated parts

• general h 20,000

• special, easy changeable (wear plates) h 8,000

• refractory h 8,000

Ash transporting parts

• general h 16,000

•special, easy changeable h 8,000

Load changes

•load range 50 - 90% %of

MCR/min ±6

• load range 30 - 100% %of

MCR/min ±4

Start-up and backup firing

• capacity %MCR 35

• turn-down ratio - 1:5

B0/FG-8

60



Guarantees Unit Data

Rejection

Further to the stipulations stated in other parts of the Tender Documents the Owner/Owner's Representative reserves the right to reject in the following:

Should the deterioration of the guarantee values be greater than the following values then the Owner/Owner's Representative shall have the right to reject the respective scope of this Section

MCR of turbine generator % 10

Specific heat consumption % 10

Auxiliary consumption % 10

Starting and loading time % 30

Live steam and reheat steam temperature deviation K 8

Effective vibration velocity mm/s 2.5

Oxygen content in feed water or condensate mg/l 0.02

or any other guarantee value is not met.

B0/FG-9

61



Design Data and Guarantees for I&C Equipment

Unit Data

General guarantees for I&C equipment With respect to the guarantees, acceptance tests and tolerances, the appropriate IEC recommendations or the valid national standards to be given by the Contractor will apply as far as they do not contradict to this specification.

Closed loop control systems All control loops shall be stable for all operating conditions and in all load ranges, and shall have optimum performance in compli-ance with the present standards. Due to interconnections, the control loops assigned to the main controlled variables shall not be considered as separate units.

They shall be matched in such a way that optimum control of the unit is accomplished in compliance with the requirements.

For closed loop control systems the quality of control shall be such that for the load changes specified, not only shall control parameter overshoot values not exceed the amount specified below but also that all such overshoot values shall return to the set value in a sinusoidal manner at a rate of not more than 35% in wave amplitude for each successive half cycle, giving steady state conditions after 3 cycles of overshoot.

The Contractor shall also demonstrate during the trial operation period that the various control systems meet the specified guarantees. The magnitude of the overshoots to be guaranteed is specified for constant load and load variations in the following text.

Definition: Load variation means change in fuel feed with a maximum rate of change of 10% live-steam flow per minute. limited to 3 minutes within the possible load range of the boiler.

Overshoots

a) Live-steam temperature:

constant load K ±4

• load variation K ±10

b) Live-steam pressure: bar 145

• constant load bar ± 1

• load variation bar ±4

B0/FG-10

62




Unit Data

c) Reheat steam temperature:

• constant load K ±4

• load variation K ±10

d) Boiler drum level:

• constant load mm ±25

• load variation mm ± 50

e) Boiler furnace pressure:

• constant load mbar ±3

• load variation mbar ±8

f) Combustion oxygen content:

• constant load %O2 ±0.4

� load variation %O2 ± 1.0

g) load variation Steam pressure and steam temperature reducing station HP bypass control

• constant load bar/oC ±1.5/±5

• load variation bar/oC ± 3/ ± 10

Under all operating conditions, the noise level of control valves shall not exceed measured at one meter distance.

dB(A) 85

To make sure that the permissible noise level is under no circumstances exceeded, the requirements in respect of the pipeline and insulation design to be fulfilled by the piping an insulation contractor shall be specified by the Contractor with the tender.

Other control and monitoring systems

The Contractor shall guarantee that the equipment provided is within the tolerances stated in the specification. The Contractor shall also guarantee that the equipment carries out in a safe and efficient manner the task for which it is provided. The quoted values data shall be guaranteed.

Testing procedures

All components supplied shall be tested in accordance with the requirements and the individual guarantees and the general performance of the installation shall be demonstrated at the tests during erection and the acceptance and performance tests.

B0/FG-11

63




Unit Data

Acceptance tests serve to provide evidence of the warranted performance

• the functions of individual equipment and/or equipment assemblies and also for

• good functioning between control equip. and controlled system

Acceptance tests shall be performed for the closed loop control system only.

For all other parts and systems, successful and faultless functioning during the time of completion, first start-up and the trial runs and random acceptance tests shall be taken as an acceptance test.

The Client or his representative will perform tests on completion in accordance with the requirements specified in the contract, e.g. checking of measuring circuit accuracy's, control processes, signal combinations, perfect operation of sequence or logic controls, etc.

Acceptance tests for closed loop control

How well the supplied control equipment and the controlled system work together under operating conditions will be checked during the control process.

The control process is the variation of the controlled variable in time under the influence of intentional (test) disturbances and/or operational disturbances .

The acceptance test is a comparison between the warranted and measured control process.

The acceptance test is successfully performed if the total of disturbance influences, including the test disturbance and the influences caused by the test disturbance in the system, are under control to a degree whereby the warranties concerning the control quality are fulfilled.

As measurement tolerances, ±1% of the set values to be warranted are permissible.

The acceptance test shall be repeated if, due to extraordinary disturbances in operation during the test, the control process does not correspond to the control process under normal operating conditions.

B0/FG-12

64


Section BO: General Specification


Unit Data

If the main performance data are not fulfilled during the accep-tance tests, the Contractor shall be obliged as a first measure to improve the supplied control equipment by suitable control Owner/Owner's Representativeing measures making full use of all theoretical and equipment Owner/Owner's Representativeing possibilities e.g. by

• load dependent parameter variation • disturbance variable feed forward

• further optimization efforts

• modification of characteristics curve of control valves and actuators etc.

For this purposes the Contractor is given the chance to modify the equipment in a reasonable time specified by the Client according to the system operation needs.

If, after final optimization, the quality of the closed loop control does not meet the requirements the Contractor shall be obliged to take the actual transient functions at the plant and to compute the theoretical possible quality of the control loops based on the actual data.

The Contractor of the equipment involved, the Client and/or his representative reserve the right to participate in these tests.

If the actual achieved control deviation does not exceed those based on the theoretically calculated possible control quality, the requirements shall be considered as fulfilled.

Should the plant fail to meet the above guarantees after due account has been taken of the above specified tolerances, the plant will be made available to the Contractor so as to allow the Contractor to make good the plant by modifying or replacing defective or wrongly designed parts.

If, even after remedial measures have been carried out, the required guaranteed values are not achieved, then the client shall be entitled to reject the complete plant or parts thereof.

B0/FG-13

65

BPDB, Barapukuria Power Plant 250 MW Bidder/ Contractor


Guarantees Data- Water Storage and Treatment Systems Unit Data

(to be completed by the Bidder)

Demineralization water plant

Net continues flow rate each line at design conditions m3/h Net treated water volume per cycle each line m3 Cycle length (service time) h Regeneration time h Chemical consumption cation/anion per regeneration: • HCI 100% each line kg/cycle • NaOH 100% each line kg/cycle Chemical consumption mixed bed per regeneration: • HCI 100% each line kg/cycle NaOH 100% each line kg/cycle Quality of treated water:

• conductivity at 25˚C (measured after cation exchanger)

µS/cm <0.01

• total iron (Fe) mg/I <0.02 • total copper (Cu) mg/I <0.003 • silica (SiO2) mg/I <0.02 • sodium ((Na) mg/I <0.01

B0/FG-14

66

BPDB, Barapukuria Power Plant 250 MW Bidder/ Contractor


Time Schedule Days after effective

Date Date

Anticipated time schedule

• Time from Award of Contract to FOB (main components)

• Time required for transportation

• Time required for erection and commissioning

• Provisional Taking Over

B0/FZ-1

67

Table of Contents

0. xxx 0.1 XXX 0.2 XXX 0.3 XXX 0.4 XXX 0.5 XXX 0.6 General Technical Requirements

0.6.1 General requirements 0.6.2 Standards and codes 0.6.3 Plant and equipment identification (e.g. Power Plant

Coding System KKS)

0.6.4 Marking and labeling of crates and packages 0.6.5 Corrosion protection coaling and galvanizing 0.6.6 Vibration 0.6.7 Standardization of makes 0.6.8 Accessibility 0.6.9 Signs 0.6.10 Units of measurement 0.6.11 Ways, stairs, ladders, balustrades 0.6.12 Hazardous areas fire protection provisions 0.6.13 Maintenance isolation 0.6.14 Materials 0.6.15 Pre-service cleaning and protection of plant equipment 0.6.16 Mechanical equipment 0.6.16.1 Pumps 0.6.16.2 Piping and accessories

0.6.16.2.1 Standards and general conditions

0.6. 16.2.2 Material and construction standards

0.6.16.2.3 Bolts and nuts 0.6.16.2.4 Pipe supports and anchors 0.6.16.2.5 Cleaning at workshop 0.6.16.2.6 Cleaning at site 0.6.16.2.7 Wall boxes and collars 0.6. 16.2.8 Expansion and flexibility 0.6.16.3 Piping design criteria 0.6.16.4 Welding and heat treatment 0.6.16.4.1 Responsibility 0.6.16.4.2 Required documents

0.6. I 6.4.3 Welding procedure qualification

0.6.16.4.4 Personnel qualification 0.6. 16.4.5 Welding process 0.6.16.4.6 Pre-heating and heat treatment

0.6. 16.4.7 Documentation 0.6.16.5 Valves, steam traps, condensate drainers, safety

valves, control valves

0.6.16.6 Insulation

68

0.6.16.7 Vessels, tanks, heat exchanger 0.6.17 Electrical equipment and works 0.6.17.1 Standards 0.6.17.2 Standard voltages 0.6.17.3 Climatic conditions 0.6.17.4 Inductive interferences 0.6.17.5 Color code system for switchgear, for local switching

measurement-control-signaling cabinets and for mimic diagrams


0.6.17.7 Protective measures 0.6.17.8 Auxiliary equipment 0.6.17.9 Requirements for local cubicles and local housings for

e.g. switchgear, control, measurement and signaling equipment

0.6.17.10 Local control points and level control cabinets

0.6.17.11 Terminal boxes and terminal cabinets 0.6.17 .12 Explosion proof equipment 0.6.17 .13 Keys and key cabinets 0.6.17. I 4 Electric motors 0.6.17.14.1 High voltage motors 0.6.17 .14.2 Low voltage AC motors 0.6.17 .14.3 Actuator drives 0.6.17.14.4 DC motors 0.6.17.14.5 Painting

0.6.17 .14.6 Protection against explosion hazards

0.6.17.14.7 Frequency converters 0.6.17 .14.8 Tests 0.6.17 .14.9 Motor list 0.6.17 .15 Labels 0.6.18 Instrumentation and control 0.6.18.1 Measuring units 0.6.18.2 Sizes of indicators, recorders, etc. 0.6.18.3 Protection and safety interlocks 0.6.18.4 Special local conditions 0.6.18.5 Tests 0.6.18.6 Field equipment 0.6.18.6.1 Measuring systems/transmitters

0.6.18.6.2 Flow measurements 0.6.18.6.3 Temperature measurements 0.6.18.6.4 Pressure measurements 0.6. 18.6.5 Analyses measurements 0.6. 18.6.6 Level measurements 0.6. 18.6.7 Electrical measurements 0.6. 18.6.8 Position measurements 0.6. 18.6.9 Contact devices 0.6.18.6.10 Vibration measurements. 0.6.18.6.11 Control valves 0.6.18.6. 12 Actuators

69

0.6.18.6.13. Local instrumentation 0.6.18.7 Racks, junction boxes 0.6.18.8 Transmitter racks and piping 0.6.18.9 Programmable logic controller 0.6.18.10 Control cubicles

70

0.6 General Technical Requirements

0.6.1 General requirements

The following directions, information and technical requirements for design, engineering, layout, erection, installation and testing shall be observed as far as they are applicable for all equipment to be delivered. The requirements stated in this Section of General Technical Requirements are valid for all sections of the specification, except only where additional and/or special requirements are specified.

Any changes on the design of any part, of the Plant, which may become necessary after signing of the Contract have to be submitted by the Contractor in writing to the Owner/Owner's representative for approval, being sufficiently substantiated and justified.

The Plant shall be brand new and clean, and designed, manufactured and arranged so that it will have a functional design and a pleasant appearance. All parts of the Plant shall be arranged in such a manner as to facilitate surveillance by the operator and to ease maintenance, operation and control.

The parts of the Plant shall be designed and arranged so that they can be easily inspected, cleaned, erected and dismantled without necessitating large scale dismantling of other parts of the plant. They shall be designed, I1lClnufactured and put into operation in accordance with the latest recognized rules of workmanship, modern engineering practice and with good standards of prudence applicable to the international electricity generation industry which would have been expected to accomplish the desired result at the lowest reasonable cost consistent with reliability, safety and expedition.

The regulations, standards and guidelines listed in the Specification as well as all applicable laws and governmental decrees, regulations, orders, etc. shall be observed in the design, calculation, manufacture, erection, installation, testing, commissioning and start-up of all parts of the Plant.

The following shall be considered in the design and engineering of the Plant facilities:

• All parts of the Plant shall be suitable in every respect for continuous operation at maximum output as well as part loads and expected transient operating conditions peculiar to the site and shall be able to safely withstand the stresses arising from the operating conditions without any reduction in its planned life which shall be at least equal to 200,000 operating hours.

• The Contractor shall familiarize himself with the conditions on site and in the country, especially with respect to transportation of heavy loads and flood.

• Suitable and automatically acting protection and safety measures shall be provided for automatic load reduction or shut down of equipment in case of abnormal operating conditions.

• Switch over to stand-by units shall be automatically, as far as required for continuous Plant operation without interruption of Plant operation.

• In case of equipment and/or system shut down process conditioned drainage of

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components (such as pipelines, tanks, etc.) shall be performed automatically or manually from the control room.

• Minor equipment which, in case of failure would cause a failure of a power generation unit and/or the Plant is to be provided with a stand-by facility in order to ensure further operation of the power generation unit or the Plant.

• All live, moving and rotating parts shall be provided with appropriate effective protection in order to avoid danger to the operating staff. All metal parts shall be electrically grounded.

• All equipment shall be designed to ensure start-up from any condition, i.e. from cold, warm or hot condition without necessitating special or preparatory measures.

• Special attention shall be paid to interchangeability of plant components.

• The project language shall be English.

0.6.2 Standards and codes

The work must be performed according to the most recent relevant codes, standards, accident prevention regulations and legal regulations.

All materials and equipment supplied and all work carried out as well as calculation sheets, drawings, quality and Class of goods, methods of inspection, specific design features of equipment and parts and acceptances of partial plants shall comply in every respect with the following technical standards, codes and regulations .

• Statutory safety regulations for equipment items (e.g. for noise preventions).

• Accident prevention regulations of the Employer's liability insurance association, Regulations and rules of the Factory and Shop Inspectorate, recommendations, directives and rules, Steel-Iron-Material Specifications, Material Specifications and Specification of Pressure Vessel Code.

• Internationally recognized standards may apply for standards and regulations.

The Contractor shall propose the international standard chosen by himself.

If this standard once is approved, the Contractor has to follow up. No standard mix will be all owed.

It is the Contractor's responsibility to provide sufficient evidence that any national or other standard the Contractor proposes will ensure a high standard.

Before starting his works, the Contractor shall deliver those standards in English language, which will be used on site to the Owner/Owner's representative and the Engineer.

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0.6.3 Plant and equipment identification (e.g. Power Plant Coding System KKS)

The Contractor shall apply a plant identification system showing the name and number of each item of plant and its respective arrangement drawing number and add any additional items necessary to fully identify the plant. The identification and numbering of equipment, systems, items, etc. of supply, as well as of all documents and drawings shall be in accordance with the IDENTlFICA TION system (KraftwerksJiennzeichnungssystem = Power Plant Coding System PPCS) or equal. The IDENTIFICATION system is available from

VGB-Kraftwerkstechnik GmbH, VerIag technisch-wissenschaftlicher Schriften Klinkestrasse 27 - 31,45136 Essen, Germany.

The Contractor shall work with this or any equivalent system that the works me going on smoothly.

There is to be only one description for anyone item of plant and this must be used consistently for plant, electrical and instrumentation designations throughout.

The Contractor shall supply all labels, nameplates, instruction and warning plates necessary for the identification and safe operation of the plant, and all inscriptions shall be in the English/Bangla languages.

All labels, nameplates, instruction and warning plates shall be securely fixed to items of plant and equipment with stainless steel rivets, plated self tapping screws or other approved means. The use of adhesives will not be permitted.

Nameplates for plant and equipment identification and record purposes shall be manufactured from stainless steel or aluminum with a mat or satin finish, and engraved with black lettering of a size which is legible from the working position.

Warning plates shall be manufactured from stainless steel or aluminum engraved red white lettering on a white background and sited in the position where they afford maximum safety of personnel.

All equipment within panels and desks shall be individually identified by satin or mat finish stainless steel or aluminum labels, or laminated plastic labels where approved.

Each circuit breaker panel, electrical control panel, relay panel, etc. shall have a circuit designation label on the front as well as on the rear panels engraved with black lettering in accordance with the circuit designation system. Circuit designations must be precise and convey complete information. There should be no doubt whatsoever for the operation as to which area of the plant a particular feeder is supplying with power. Labels such as interconnector 1, feeder 2 are not acceptable. Corridor type panels shall in addition have circuit designation labels within the panels.

Pipe work systems shall be identified with a color identification systems in conformity with the colors according to the chosen standards, with colors af the nameplates and, if necessary by color bands and with identification numbering and plain language. The direction of flow shall be shown.

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Each valve shall be fitted with a stainless steel or aluminum name plate indicating the valve service and reference number in accordance with the IDENTIFICATION system.

Where possible valve nameplates shall be circular and fitted under the hand wheel captive nut. They have to be of such a diameter that there is no danger for persons operating the valve or that they do not prevent lock-off of this valve; on check valves and small valves the Contractor may provide rectangular nameplates fitted to brackets on the valve or attached to a wall or steelwork in a convenient position adjacent to the valve.

0.6.4 Marking and labeling of crates and packages

Each crate or package is to contain a packing list in a waterproof envelope. All items of material arc to be clearly marked for easy identification against the packing list.

All cases, packages, etc. are to be clearly marked on the outside to indicate the total weight, where the weight is bearing and the correct position of the slings and arc to bear all identification mark relating them to the appropriate shipping documents.

All stencil marks on the outside of cases are either to be made in waterproof material or protected by shellac or varnish to prevent obliteration in transit.

0.6.5 Corrosion protection, coating and galvanizing

This specification shall be used for the corrosion protection of steel structures, components, pipings and equipment in general which are installed in confined areas (indoors) or outdoors. Surface preparation, as well as protective coatings and coating systems are based on this specification in order to assure that structural parts of different suppliers will get a corrosion protection of similar and high quality . Coating material shall only be supplied by manufacturers with international experience and their products can be obtained internationally. Regarding maintenance work (storage), application and supervision of coating work, choice of coating suppliers should be minimized. At any rate, similar parts of structures/components (such as structural steel, containers, piping, etc.) shall only be coated with products of one individual manufacturer.

The manufacturer's materials and equipment used, the methods of application and the quality of work shall at nil times be subject to the inspection and approval of the Owner/Owner's representntive or his representative.

Codes and standards

Applicable standards are to be proposed for: • indication of pipe-lines according to flowing material • surface roughness

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• tight blasting agents • corrosion protection, hot dip batch galvanizing of single parts, requirements and

testing • corrosion protection of structural steel work through protective coatings and

topcoats • preparation of steel substrates before application of paints and associated

products • paints and varnishes - corrosion protection of steel structures by protective paint

systems • color card • Swedish standard or equivalent for steel surface preparation steel structure

painting council.

Surface preparation and cleaning of surfaces in the shop

Prior to blasting, areas have to be cleaned from

• oil • grease • paint residues • splatters • mill scale • welding splashes and • Welding slag.

Sharp edges have to be rounded off.

Contamination caused by salts, acids and alkali solutions shall be eliminated by rinsing with water up to a pH value of 6-8.

The preparation of substrates shall be carried out on the basis of the specifications according to proposed standards.

After blasting, an anchor profile of 25 - 50 shall be achieved. Blasted surfaces have to be provided with a prime coat of the considered coating system immediately after blasting.

Cleaning to be performed on site

Steel work protected by shop primer after arrival on site must be c1eancd of salt, sand, oil, etc. before the first coat of paint is applied on site. Shop primer damaged during transport must be rectified by blast-cleaning and coating before application of the site coats.

Wood shall not be used.

If a protective coating of concrete is required, concrete shall be allowed to cure before painting.

Transport and erection damages, as well as damages which result out of additional welding have to be repaired as soon as possible. The damaged areas have to be derusted with rotating or steel brushes, abrasive wheels, abrasive blasting according to the chosen standards.

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Cleaning of prime and intermediate coats (if required)

To prevent contamination by mineral oil products, areas with prime and intermediate coat have to be treated with suitable cleaning agent. Cleaning has to be done free of residues, e.g. with alkaline detergents and thorough washing done with fresh water. Rusty spots have to be removed according to required purity. Metallic areas which are provided with temporary corrosion protection have to be cleaned. No oxidation products shall remain on the surface. Furthermore it has to be taken care that on hot components no destructive nor reaction products will be released when heating which could injure insulation. Application procedure

When using the provided coating material, strict adherence to all application instructions given in product data of coating. manufacturer is necessary. To obtain the maximum performance, technical data as well as application instructions for the individual coating material have to be strictly followed.

For a multi-layer coating system each layer has to have a different color shade in order to clearly identify number of coats applied.

The last finish coat has to be applied in the specified color shade, to be agreed by the Owner/Owner's representative.

The interval between applying the different coats has to follow according to supplier's precautions. Each layer has to be cleaned and released from spray dust before the next layer will be applied. Prior to applying a further layer, the last one has to be repaired. All coatings have to be applied without retarding.

Following application procedures are allowed:

• prime coats by airless spray

areas like disconnections, angles, comers, etc. which are difficult to be reached can be applied by brush or roller

• repair of prime coat by brush • finish coats

• at works by airless spray, roller or brush

• at site by roller or brush or airless spray.

When applying coating systems by roller, rollers have to be of kind and quality which make an appropriate application possible.

Control areas in accordance with the coating supplier's instructions have to be applied. For this procedure, a schedule for control areas has to be prepared by the Contractor and coating supplier which corresponds with the requirements of the warranty agreement.

Number and performance of the control areas have to be done in accordance with the chosen standards and have to be documented in writing.

No application may take place neither when the relative humidity will not be within the given limit nor in case of fog, dust, rain, snow or hail or when it can be assumed

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that such conditions of poor weather within 2 hours after application can arise.

Temperature of the coated parts has always to be above 5°C and 3 K above dew point.

All specified dry film thicknesses (DFT) are minimum thicknesses.

Welding seams mounted at site have to be taped with an adhesive tape of about 30-50 mm after surface preparation (blasting or manual derusting) and prior to application in the manufacturing plant and to be coated with stripping coat.

Chequered plates, nap plates, etc. have not to be covered with adhesive tape, but have to be coated with stripping coat in a dry film thickness of at least 150 µm.

Edging lines on steel structure have to be taped prior to application and after blasting in sufficient width or have to be protected with varnish before application. Thickness of prime coat may be 50 µm max.

During repairing works at site on shop-primed structures, it is important that different coats will have different colour shades. Number of layers has to be the same as the original coating system to be used.

Application of temporary primer on structures which have to be insulated has to be in accordance with a sufficient corrosion protection for the period of storage respectively erection time.

Galvanizing

Galvanizing work shall conform in all respects to the chosen standards and shall be performed by the hot dip process unless otherwise specified.

It is essential that details of steel members and assemblies which arc to be hot-dip galvanized should be designed to suit the requirements of the process. They should be in accordance with the chosen standards.

Vent holes and drain holes shall be provided to avoid high internal pressures and air locks during immersion and to ensure that molten zinc is not retained in pockets during withdrawal.

Careful cleaning of welds is necessary before welded assemblies are dipped.

All defects of the steel surface including cracks, surface laminations, laps and folds shall be removed in accordance with BS 4360. All drilling, cutting, welding, forming and final fabrication of unit members and assemblies shall be completed, where feasible, before the structures are galvanized.

The minimum average coating weight shall be as specified in the chosen standards. Structural steel items shall be first grit-blasted (Sa 2 1/2) or pickled in a bath, and the minimum average coating weight on steel sections 5 mm thick and over shall be 900 g/m2, on steel sections 2 - 5 mm thick 600 g/m2 .

Galvanized contact surfaces to be joined by high-tensile friction-grip bolts shall be roughened before assembly so that the required slip factor is achieved. Care shall

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be taken to ensure that the roughening is confined to the area of the mating faces.

Protected slings must be used for off-loading and erection. Galvanized work which is to be stored at the works or on site shall be stacked so as to provide adequate ventilation of all surfaces to avoid wet storage staining (white rust).

Small areas of the galvanized coating damaged in any way shall be restored by:

• cleaning the area of any weld slag and thorough wire brushing to give a clean surface • the application of two coats of zinc-rich paint, or the application of a low melting point

zinc alloy repair rod or powder to the damaged area, which is heated to 300°C.

Connections between galvanized surfaces and copper, copper alloy or aluminum surfaces shall be protected by suitable tape wrapping

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Coating Systems

System-No

Surface location Temp.oC Surface

preparation Coating systems

No.of coats

Generic type Dry film thickness

(DFT) per coat µm

Total DFT µm

1

Structural steel works, piping, up to 120 SA 2.5 Primer 1 Zinc-Epoxy 80 80

vessels, tanks

INDOOR Finish 1 Epoxy High Solid 80 80 160

2

Structural steel works, piping, up to 120 SA 2.5 Primer 1 Zinc-Epoxy 80 80

vessels, tanks

OUTDOOR Intermediate 1-2 Epoxy High Solid 160 160 Finish 1 2-Comp.Polyurethane 50 50 290

3 Piping, tanks, etc. up to 120 SA 2.5 Primer 1 Zinc-Epoxy 50 50

INDOOR and OUTDOOR, Insulated .

4

Pumps, motors, other equipment up to 120 SA2.5 Primer 1 Zinc-Epoxy 80 80

OUTDOOR Intermediate 1 Epoxy High Solid 110 110

Finish 1 2-Comp.Polyurethane 50 50

240

5 Pumps, motors, other equipment

up to 120 SA 2.5 Primer 1 Zinc-Epoxy 80 80

Finish 2 Epoxy High Solid 50 100

INDOOR 180

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Coating Systems

System-No

Surface location Temp.oC Surface

preparation Coating systems

No.of coats

Generic type Dry film thickness

(DFT) per coat µm

Total DFT µm

6

Piping, reactors > 120 SA 2.5 Primer 1 Zinc Ethysilicate 75 75

OUTDOOR

Insulated

7

Stacks < 120 SA 2.5 Primer I Zinc Ethysilicate 75 75

OUTDOOR

<200 Finish 2 Silicone Acrylic 50 100 175

8

Steel surfaces 200 - 450 SA 2.5 Primer I Zinc Ethysilicate 75 75

Un insulated

Finish 2 Silicone Aluminium 25 50 125

9 Galvanized surfaces up to 120

Mechanical cleaning from contaminants and zinc salts by means of washing or steam or sweep- jetting blasting with fme sand

When Finish Coat is required, such as sea climate with chloride exposure

I Epoxy High Solid� 125 125

10 Steel surfaces permanently in contact with water

Medium temp.oC up to 60

SA 2.5 Prime and Finish Coat in One

1 Glassflake reinforced

High Solid Epoxy. 500 500

Additional 1 x Finish Coat 2-Comp. Polyurethane, 50 µm, when exposed to UV and colour retention is required or when exposed to weathering.

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0.6.6 Vibration

Unless otherwise stated or agreed by the Owner/Owner's representative or ; the Owner/Owner's representative each rotating machine has to comply with the requirements for vibration magnitude (criterion I) designation as "zone A" stipulated by ISO Specification 10816 or equivalent for the respective group of machinery. If the vibration magnitude is greater than stipulated as "zone B", the Owner/Owner's representative has the right to reject the concerned equipment. .

0.6.7 Standardization of makes

The works shall be designed to facilitate inspection, cleaning, maintenance and repair. Continuity of supply is a prime concern. The design shall incorporate every reasonable precaution and provision for the safety of all those concerned in the operation and maintenance of the works. The plant shall be designed to operate satisfactorily under all variations of load, pressure, and temperature.

Corresponding parts throughout shall be made to gauge and be interchangeable wherever possible.

All equipment performing similar functions shall be of the same type and manufacture, to limit the stock of spare parts required and maintains uniformity of plant and equipment to be installed.

0.6.8 Accessibility

The Contractor shall supply and erect sufficiently large safe platforms, galleries, stairways and access ways necessary for providing safe and easy access to all the plant items for operation and maintenance. The Contractor shall ensure that the whole of the access ways is of W1iform design and pattern throughout the works.

Ladders are only to be provided as an extra means of escape. No dead ends are allowed, especially where the escape way may be blocked by fire/steam, etc.

The design of all stairways, access ways etc. shall conform to the requirements of Section 0.6.11.

0.6.9 Signs

General

Safety colors, safety symbols and safety signs must comply in construction, geometrical form, color and meaning with the chosen standards.

Signs for plant identification during the erection period are subject to the Owner/Owner's Representative approval.

The signs should be of a material which is weather-resistant and of sufficient durability for the conditions prevailing on site.

Mounting and installation

The positions for the signs must be chosen so that they are within the field of vision of the persons to whom they apply. The signs should be permanently attached.

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Temporarily dangerous areas (e.g. construction sites, assembly areas) may also be marked by movable signs. The safety signs must be mounted or installed in such a manner that there is no possibility of misunderstanding.

Information signs

Information signs should supply the necessary information to acquaint personnel with the physical arrangement and structure of site, buildings and equipment, e.g. floor numbers, load-carrying capacities including marking of floor areas, working loads of cranes, lifting gear and lifts, room identification, etc. The routing of underground pipes and� cables is to be indicated by substantial marker blocks showing the relevant identification numbers.

In the choice of information signs in situations not covered by the chosen standards the possibility of using pictograms should be considered. Pictograms are particularly suitable for the identification of rooms, areas and buildings in the non-technical areas of the plant, sanitary and amenities buildings, etc.

Emergency signs

In the event of accidents, all necessary information should be available immediately to those affected. Thus, a sufficient number of signs of appropriate size should be installed, e.g. escape routes (including marking of floor areas), emergency exits, fire alarms, fire extinguishers, instructions for special fire-extinguishing agents, warnings against fire-extinguishing agents (C02), first aid equipment, first aid points, accident reporting points, telephones, etc.

Mandatory signs

Signs indicating obligatory actions must be provided installed wherever certain action is necessary, e.g. do not obstruct the entrance; keep right, etc.

Signs should also indicate when the wearing of protective clothing and equipment is necessary and obligatory, e.g., protective goggles, protective clothing, helmets, head guards, breathing equipment, ear muffs, etc.

Warning signs

Warning signs should refer to the existence or possible existence of danger, e.g., flammable substances, explosive substances, corrosive or noxious substances, suspended loads, general danger, width height restriction, steps, risk of trapping, slipping, falling, etc.

In addition to warning signs, appropriate black-yellow ~trip markings should also be used where necessary.

0.6.10 Units of measurement

The Contract shall be conducted in the Systems International Units (SI) system of units in accordance with the provisions of ISO 31 and ISO 1000.

In all correspondence, technical schedules, drawings and instrument scales, the following units shall be used:

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Quantity Name of Unit Symbol

Length Millimeter mm

Mass Kilogram kg

Time Second s

Temperature Degree Celsius °C

Temperature Difference Kelvin K Electric Current Ampere A

Luminous Intensity Candela cd

Area Square meter m2

Volume Cubic meter m3

Liter I

Force Newton N

Pressure (absolute) Bar bar

Kilopascal kPa

Pressure below 1 bar Millibar mbar

Stress Newton per square millimeter N/mm2

Velocity Meter per second mls

Rotational speed Revolutions per minute rpm

Flow Cubic meter per day m3/d

Cubic meter per hour m3/h

Kilogram per hour kg/h

Liter per second L/s

metric ton per hour t/h

For gaseous substance: standard Nm3/h

cubic meter per hour (referred to

O°C and 1013 mbar)

Density Kilogram per cubic meter kg/m3

Kilogram per standard cubic Kg/Nm3

meter

Torque, moment of force Newton meter Nm Momcnt of inertia (mr2) Kilogram square meter kgm2

Work, energy or heat Joule J

Heat capacity, entropy Joule per Kelvin J/K

Calorific value Joule per cubic meter J/m3

Joule per gram J/g

Power, radiant flux Watt W

Heat release rate Watt per square meter W/m2

Thermal conductivity Watt per meter Kelvin W/mK

Dynamic viscosity Newton second per square meter Ns/m2

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Quantity Name of Unit Symbol

Kinematics' viscosity Meter squared per second m2/s

Surface tension Newton per meter N/m

Concentration Parts per million ppm

Electrical conductivity Micro Siemens per meter at 25°C µS/m

Frequency Hertz Hz

Electric charge Coulomb C

Electric potential Volt V

Electric field strength Volt per meter Vim

Electric capacitance Farad F

Electric resistance Ohm n

Conductance Siemens S

Magnetic flux Weber Wb

Magnetic flux density Tesla T

Magnetic field strength Ampere per meter A/m

Luminous flux Lumen lm

Illuminance Lux Ix

Thermal resistivity Kelvin meter per Watt Km/W

Energy Kilowatt hour kWh

For the thermodynamic properties of steam and water the latest edition of the "VDI- Wasserdampftafeln" (= Water Steam Tabular) shall be used which is based on the formulations published by the International Formulation Committee (IFC) under the title "The 1967 IFC Formulation, for Industrial Use".

0.6.11 Ways, stairs, ladders, balustrades

The Contractor shall supply all platforms, galleries and stairways necessary for providing safe and proper access to the plant for operation and efficient maintenance. The Contractor shall ensure that the type of flooring, stair treads and handrails conform to a uniform pattern throughout the whole Project.

The loads for the design of platforms, galleries etc. shall be in accordance with the section 'Design Loads' of the special civil part of these specifications.

All platforms, galleries, stairways and hand railing shall be of galvanized ,i steel unless otherwise specified.

All aspects of platforms, stairways, ladders and other access ways shall comply with the requirements of applicable 'standards.

0.6.12 Hazardous areas. fire protection provisions

Hazardous areas

The Contractor shall take full account of any special requirements concerning the

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nature, handling and storage of all fuel oils, gases and chemicals etc., and provide plant, equipment, buildings and other services accordingly, including all facilities to ensure the safety of the operating and maintenance personnel.

The Contractor shall provide drawings to define all the hazardous zones taking account of all sources of hazards under normal and abnormal operating conditions, (regardless of whether or not these areas are specifically listed in the specification).The zoning philosophy shall be subject to the approval of the Owner/Owner's representative.

In particular, equipment directly concerned with plant which may give rise to a hazardous situation shall be designed to requirements with electrical connection safety barriers or intrinsically safe equipment. Where required by the Engineer, certification shall be provided to confirm the suitability of the equipment and devices.

The Contractor shall be responsible for ensuring that all electrical equipment installed in any hazardous zone is designed and tested to suit the relevant zone classification and shall be to the approval of the Employer. Cables shall not be laid in trenches etc with fuel pipe work.

Fire protection provisions

Unless otherwise specified or agreed with the Owner/Owner's Representative, the following design principles should be observed as minimum fire prevention requirements:

• Pipeline insulation and the in-fills of cable and pipeline wall penetrations are to be of non-combustible material.

• All pipelines or vessels with internal temperatures of more than 180°C shall be so arranged as to avoid any contact with flammable liquids if fuel or lube oil lines should leak. Sufficient physical separation shall be ensured.

• Particular care should be taken to eliminate any risk of hot pipeline insulating material becoming impregnated with flammable liquids in the case of fuel or lube oil line leakage. The insulation is to be covered in its entirety, with an oil resistant sheet, over which the cladding is to be fitted.

• Cable and pipeline ducts must be so arranged and sealed as to avoid all risk of flooding with fuel oil, lube oil or any other flammable liquid. In addition to sealing the cable and pipeline ducts, the cable basements must be completely scaled against leakage from above as well, in order to preclude the ingress of lube oil or other flammable liquids.

• Covered floor ducts must be easily accessible for inspection and cleaning.

• All parts of plant and equipment are to be arranged so that no corners or pits that would be difficult to inspect and clean and in which flammable matter could collect are formed.

• Fuel preheating temperatures should be limited to a margin of at least 10K below the fuel flash point.

• Lubricating oil lines in the turbine-generator lube oil system arc not to be connected with compression-type joints but rather with welded or screwed-type points.

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• Non-combustible materials which do not release noxious or toxic fumes must be used for wall and ceiling paneling, for floor covering, and for cubicles and cabinets.

• Corners likely to collect dust respectively-coal powder shall be prevented.

0.6.13 Maintenance isolation

All major equipment shall be arranged to facilitate safe isolation frol11 all hazards for maintenance purposes. In addition all valves must be capable of being locked either in the open or closed position by means of a chain and padlock.

Non return valves are not acceptable as a means of isolation.

0.6.14 Materials

All materials shall be brand new and of the best quality for use in the conditions and the variations in temperature and pressure that will be encountered in service without undue distortion or deterioration or the setting up of undue strains in any part that might affect the efficiency and reliability of the plant.

All materials shall correspond either to the approved standards and the respective code number or to exact analysis data, and full information concerning properties and applied heat, chemical and mechanical treatment shall be submitted for Owner/Owner's Representant's spot check.

Special attention must be paid to eliminating the possibility of corrosion resulting from galvanic effects. Design, selection of materials and all methods of erection shall be such as to keep these effects to a minimum. Materials complying with codes and standards listed below shall be used for the design and construction work.

Unless the materials meet these codes and standards, they shall be subject to the Owner/Owner's representative's spot check.

Materials and standards

(A) a. Structural steel Standards chosen by the Bidder b. Structural steel tubes Standards chosen by the Bidder c. Crane rail Standards chosen by the Bidder (B) a. High strength friction grip bolts

(H.S.F.G. bolt) Standards chosen by the Bidder

b. Torque shearing bolt c. Ordinary bolt (C) Electrodes for arc welding Standards chosen by the Bidder (D) Ordinary Portland cement Standards chosen by the Bidder (F) Reinforcing bars Standards chosen by the Bidder

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0.6.15 Pre-service cleaning and protection of plant equipment

This clause covers mechanical and pre-service cleaning and protection of the plant items and equipment at the Manufacturer's workshop and at site that are not subsequently to be painted.

Cleaning of fabricated component items shall be carried out after fabrication and final heat treatment or welding at manufacturers' works or at site, as appropriate.

In the event of the surfaces not being cleaned to the Employer's or Engineer's satisfaction, such parts of the cleaning procedures or agreed alternatives as are deemed necessary to overcome the deficiencies shall be carried out at the Contractor's sole expense.

Mechanical cleaning as opposed to alternative chemical cleaning is the preferred method for workshop cleaning except where this. is precluded by design or access c0!lsiderations.

Machined surfaces shall be protected during the cleaning operations. For recleaning small areas, hand cleaning by wire brushing may be permitted. Wire brushes used on austenitic materials shall have austenitic steel bristles.

Austenitic stainless steels, copper and aluminum alloys, cast iron, bimetallic and metallic/plastic items, and components fabricated by spot welding or riveting shall not be chemically cleaned. All weld areas shall be suitably stress-relieved before chemical cleaning

At an appropriate time, the Contractor shall submit drawings of temporary pipe work necessary to carry out the pre-service cleaning simultaneously with a list of works to be carried out on the pipelines, heaters, feed water I tanks, vessels etc. to connect the temporary pipe work with the parts of equipment to be cleaned.

Further, the Contractor shall submit at the. same time the basic draft of the cleaning procedure and of the treatment of wastes.

Not less than six months prior to the commencement of any site cleaning, the Contractor has to submit programs covering all procedures, lists of chemicals, calculations which quote the velocities, temperatures handpipework forces and movements imposed during site cleaning.

All necessary equipment, provisions, chemicals etc. are to be provided by the Contractor.

All tests, analyses, etc. as required arc to be performed by the Contractor.

Besides this, the Contractor shall take over all responsibility for the treatment and disposal of wastes according to the local law and to the satisfaction of the Owner/Owner's representative.

The date at which cleaning of plant equipment will be carried out at site shall be notified to the Owner/Owner's representative at least 20 days in advance.

The Contractor shall take all necessary precautions to ensure that the internal surf.1ces of all plant are kept clean and free from injurious matter during erection.

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When all plant has been erected and lagged or at such other time as may be agreed with the Owner/Owner's representative for sub-assemblies, the installation shall undergo a procedure for site cleaning proposed by the Contractor and subject to the approval of the Employer.

0.6.16 Mechanical equipment

0.6.16.1 Pumps

General

All pumps shall be designed for continuous operation unless otherwise specified.

Pumps shall be installed in positions convenient for operation and servicing. Where multiple pump installations are required, each pump and its associated equipment shall be arranged in such a manner as to permit easy access for operation, maintenance and pump removal without interrupting plant operation. Pumps installed for parallel operation or as stand-by sets are to be of identical design, i.e. interchangeable.

Lifting lugs and eyes and other special tackle shall be provided as necessary to permit easy handling of the pump and its components.

General design and construction

All pumps shall be designed to withstand a test pressure of 1.5 times the maximum possible pump shutoff pressure under maximum suction pressure conditions. If a pump can operate at sub-atmospheric suction conditions, the entire pump shall be designed for full vacuum.

All pump shafts shall be of ample size to transmit the maximum possible output from the prime mover. The pump shaft and coupling are to be so dimensioned that the maximum permissible torque of the shaft is higher than the maximum transmissible torque of the coupling. Directly coupled pumps shall be used preferably.

Renewable wear rings shall be fitted to the casing and impeller where economically justified.

All pumps and accessories in contact with the pumped fluid shall be constructed of materials specifically designed for the conditions and nature of the pumped fluid, and be resistant to erosion and corrosion.

Product water flushing lines are to be supplied for each pump handling seawater to avoid corrosion if the pump is out of operation for extended periods.

The pump glands or mechanical seals shall be so arranged that repackaging or fitting of replacement seals can be carried out with the minimum of disruption to plant operation. In case of operating under vacuum conditions liquid sealing is to be provided.

The pump casing shall preferably be split for ease of maintenance and be

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designed such that the impeller and shaft are capable of being withdrawn from the casing without disturbing any of the main paperwork. and valves carrying the pumped fluid. In general, all horizontal pumps with draw-outrotors are to be fitted with a coupling to facilitate disassembly without removing the motor. Pull-out design of the shaft shall be applied to vertical wet pit and dry pit pumps as well.

Each .horizontal pump shall be mounted with its drive on a common base plate of rigid construction. Vertical pumps are to be provided with foundation frames. In case of submersible pumps suitable frames shall be provided in the pump sump. It shall however be possible love these pumps without entering the sump.

Pumps must be carefully set to ensure that the net positive suction head available under all operating conditions will be adequate for the type of pump employed. The NPSH values are to be referred to the least favorable operating conditions -lowest atmospheric pressure, lowest level of water <W the suction side of the pump, and highest temperature of the pumped fluid. An adequate safety margin of normally greater than 1 m to the max. NPSI-1 required shall be provided.

Pumps shall operate smoothly throughout the speed range up to their operating speeds. The first coupled critical speed must be at least 20% higher than the maximum operating speed. The determination of the shaft diameter and the distance between two consecutive bearings must include a sufficiently large safety margin to satisfy this condition.

Where necessary, the pumps are to be fitted with devices to ensure a minimum throughput.

Bearings

For large pumps the bearings shall be of automatic oil lubricated sleeve type, unless otherwise specified. Bearings on vertical shaft pumps shall be so spaced to prevent shaft whipping or vibration under any mode of operation.

Bearings housings on horizontal shaft pumps shall be designed to enable the bearings to be replaced without removing the pump or motor from its mounting. Bearing housings on horizontal shaft pumps shall be effectively protected against the ingress of water, pumped fluid and dust by suitable nonferrous deflectors.

All bearing oil wells shall be fitted with visual oil level indicators. Non pressure-oil lubricated bearings shall be equipped with constant level oilers.

Pumps characteristics

When several pumps arc installed for the same service, they shall be suitable for unrestricted parallel operation.

The pump flow/head characteristics shall be such that within the operation range the head will continuously increase with decreasing flow, maximum head (shut off head) being at least 10% higher than the duty point head.

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Unless otherwise specified all pumps shall be capable of operating at 110% of the rated capacity at the rated delivery head. Maximum size impellers shall not be quoted for. By installation of a new impeller a head increase of 5% minimum shall be possible. The performance of the drive motor is to be determined according to the above mentioned technical requirements and to the requirements as specified in the electrical part. Fittings

All pumps shall be installed with isolating valves, a non-return valve and suction and discharge pressure gauges unless otherwise stated. Accessible couplings shall be supplied with removable type guards.

Coupling halves shall be machine matched to ensure accurate alignment. Couplings as well as gears must have a rated capacity of at least 120% of the maximal potential power transmission requirement.

All positive displacement pumps shall be fitted with a discharge relief valve capable of passing the maximum pump delivery flow.

Venting valves shall be fitted to all pumps at suitable points on the pump casing unless the pump is self-venting, due to the arrangement of the suction and discharge nozzles. Drainage facilities shall be provided on the pump casing or adjacent pipe work to facilitate the dismantling of pumps.

All pumps other than submersible pumps shall have temporary strainers fitted in the suction pipe work during all initial running and commissioning phases. Permanent strainers shall be provided where specified.


As far as arrangement and number of valves for drains and vents, etc., are concerned, the stipulation of this article define the minimum requirements.

The intent of this chapter is to describe the general technical requirements and essential particulars of pipes, valves, fittings, expansion joints, insulation as well as the complete power piping system furnished, fabricated, shop tested, delivered, completely erected land installed, clean inside and outside, in first class condition throughout, hydrostatically field-tested and demonstrated to be in a condition to operate commercially and continuously in a manner acceptable to the Owner/Owner/Owner's representative up to maximum operating conditions.


The intent of this chapter is to describe the general technical requirements and essential particulars of pipes, valves, fittings, expansion joints, insulation as well as the complete power piping system furnished, fabricated, shop tested, delivered, completely erected land installed, clean inside and outside, in first class condition throughout, hydrostatically field-tested and demonstrated to be in a condition to operate commercially and continuously in a manner acceptable to the Owner/Owner/Owner's representative up to maximum operating conditions. As far as arrangement and number of valves for drains and vents, etc., are concerned, the stipulation of this article defines the minimum requirements.

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0.6.16.2.1Standards and general conditions

Piping and valves shall comply with currently approved applicable codes, specifications and standards (latest revisions), such as DIN, American standards (A.S.A., ASTM, ASME, A WW A), Japanese standards and shall conform with the Contract specification.

All piping materials, bypasses, open blows, welding joints, flanges, bolting materials, gaskets, piping supports, turn buckle red hangers, spring hangers, guides, sway braces, vibration dampers, trays, brackets, anchors, rollers, expansion bends, operating platforms and supports of all types as well as miscellaneous structural steel and other items required to support the piping in a proper manner, shall be included in all piping systems.

The Contractor shall include all incidental components necessary for a complete installation such as vents, drain lines, drip llines, etc.

Pockets in pipelines shall be avoided wherever possible and all lines are to be provided with fittings, valves and/or traps arranged in such a way that the pipes may be completely drained when desired.

Each mechanical component requires its identification coding number.

0.6.16.2.2 Material and construction standards

Welding wires and electrodes material for welded connection of pipe systems shall be according to relevant standards or codes of the appertaining

piping system of the recommendation of the weld-material supplier. Adequate information documents shall be sent to the Owner/Owner's Representative.

All valves. expansion joints, thermometer nozzle, supports and associated equipment and instruments shall be supplied and installed by the Contractor in a manner acceptable to the Owner/Owner's Representative .

For all piping systems, separate list of pipes and list of valves. shall be submitted by the Contractor.

The Owner requires entirely and continuously-welded connections for all high pressure temperature service including welding' of pipes to the valves or other equipment. Other piping systems shall comprise all welded connections or bolting of pipe to the valves or equipment. The use of odd or short pieces of pipe in making up long runs is prohibited.

All pipe bends shall be made preferably to radii not less than five times nominal pipe diameter unless otherwise specified; they shall be true to angle and radius and maintain a true circular cross-section of the pipe without buckling or undue stretching of the pipe wall.

The Contractor shall machine completely all welded ends on piping, bends and fittings to make all welds sophisticated both in shop and field. Welding joint design shall avoid all sharp comers.

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0.6.16.2.3 Expansion and flexibility

Piping systems shall be calculated, supported, guided and anchored in such a way as to preclude excessive thrust or stress due to the combination of leading from internal pressure, thermal expansion and weight. The Contractor shall be responsible for computing expanding movements and combined stress on and weights of all major pipelines and for providing suitable supports and restraints to assure compliance with the latest rules of the available standards. Reactions at equipment connections shall be within the limits specified by the manufacturers respective equipment.

0.6.16.2.4 Pipe supports and anchors

Pipe supports and anchors shall generally be situated at those points in the building where provisions has been made to sustain the loads imposed. The cutting of floor or roof beams of the reinforcement in slabs shall not be permitted. Piping attached to a plant item shall be supported in such a way that the weight of the piping is not carried by and no stress is exerted on the plant item.

Since certain parts of the building may be constructed in reinforced concrete, the position of all pipe supports and anchors, and -the loads imposed by them, shall be determined sufficiently early to allow appropriate provisions to be made.

All pipe supports and anchors shall be preferably located at the main grid lines of the structures and buildings. Where pipe supports and anchors are required elsewhere, all the secondary beams to direct the load to the main beams and connecting pipes shall be provided by the Contractor.

Only minor loads shall be permitted to hang to the concrete slabs and subject to the approval or Owner/Owner's Representative. The supporting arrangements - inapplicable - shall be capable of supporting the weight or the piping systems when full of water during, chemical cleaning or hydraulic testing. The number and position of pipe supports shall be such that the piping may be free to move, and that lateral loading on the piping system under working conditions may be minimized.

Constant load supports shall be fitted where considered necessary.

All supports for high pressure steam and other pipes subjected to high temperature conditions shall be fastened onto the pipe under consideration of the operating conditions of the pipe supported. The material influenced by the temperature conditions shall be of nearly the same quality as the related pipe.

Supporting straps around flanges of pipes or valves or around welded joints will not be accepted. Anchors shall be attached to pipes by approved means. Main support shall be shop-fabricated and shall be positioned near the joints and valves wherever possible before the erection of the piping takes places, and shall be clamped onto the pipe by bolting wherever poss1ble.

Terminal points between pipe work supplied by different manufacturers shall be carried out as "fixed points" in such a way that at the point of connection,

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the pipe shall be fixed in a constant position if not otherwise instructed by the Engineer. The Contractor is responsible for meeting all the requirements for pipe connections established by the manufacturers of the turbine, the pumps and other relevant equipment.

0.6.16.2.5 Cleaning at workshop

On completion of all bending, flanging and other operations on pipes necessitating application of heat, with the exception of welding on site, the pipes shall be completely immersed in a pickling solution for a period not less than two hours, to remove all grit and mill scale. An inhibitor shall be used in the pickling solution. Removal of internal scale by sandblasting is not permitted.

Alternative procedures (shot blasting), according to the practice of the Contractor may be accepted, subject to approval by the Engineer.

After drying, inspection and conservation, wooden plugs, metal or plastic caps shall be securely fitted to the ends of each pipe to prevent the ingress of dirt and to protect flanges and pipe ends from damage during transportation and storage.

0.6.16.2.6 Cleaning at site

During erection, the open ends of any work shall be protected at all times by suitable temporary covers, which shall be securely fixed.

The Contractor shall make provisions for "blowing-out" procedures of the , main steam pipe work by steam and shall provide any branches, temporary. pipe work and supports that may become necessary. Disconnecting and remaking of points shall be included.

After boiling-out of the boiler and blowing-out of the several pipe systems the systems have to be passivated. The proposed process shall be fully described by the Contractor and shall be subject to the Engineer's approval.

On completion of the cleaning processes, an inspection shall be carried out in the presence of the Engineer, to ascertain the effectiveness of the processes just completed.

The criteria to be used for inspection of accessible surfaces shall be the absence of mill scale, deposits and loose debris, the presence of a clean and passivated surfaces and the absence of untreated areas. The inspection shall be carried out under clean conditions and with internal drum fittings removed, if so requested by the Engineer.

It shall be the Contractor's responsibility to remove from Site all chemicals and debris accumulated during the chemical cleaning process. Any damage caused as a result of the process shall be made good by the Contractor at his own expense, therefore an adequate insurance cover shall be a necessity for such a contingency.

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0.6.16.2. Wall boxes and collars.

The wall boxes and floor collars shall be constructed in such a way that, if necessary, they can be erected after the pipes are in position. Pipes passing through roof collars shall be provided with approved weather-hoods and cowls which shall be fixed by the Contractor.

The Contractor shall provide all the necessary wall boxes and sleeves where pipes pass through walls, floors and roofs, also the necessary supports fot) . any pipes laid in trenches. Roof collars shall be fitted with high coamings to prevent rainwater from passing through the holes.

0.6.16.2.8 Bolts and nuts

All bolts, nuts, etc. shall conform to an approved Standard. Bolts or studs which are subjected to high pressure and temperature shall be of approved high tensile alloy steel with nuts of a suitable, approved material.

All bolts or studs shall be of steel suitably machined, at the shank and under the bolt head. Washers shall be provided under nuts, and also under bolt heads, if required.

The aggressive environmental conditions must be considered when selecting material and surface protection. Bolts, nuts, etc. from suitable stainless steel shall be applied if submerged with highly corrosive media, or where contact with such media in case of un tightness, etc. can be expected. Dolts and nuts for outdoor installations, pipe installations in trenches or other applications shall be galvanised or cadmiumized if requested by the Engineer.

Dolts, nuts made from high temperature resistant materials and ones installed in enclosed parts of machines are not concerned of this regulation

0.6.16.3 Piping design criteria

The pipe work shall be designed, fabricated, erected, inspected and tested on the basis of the currently approved applicable standards and codes such as DIN, American standards (ASA; ASTM; ASME; A WW A), Japanese standards or equivalent and the additional requirements as set out below.

For the HP Live Steam and Re-heater System high alloy steel, for example material P91 (XI0CrMO VN b 91) is preferred.

For the main cooling water system GRP is preferred (see article D7).

The maximum flow velocities for the individual media must not bc ex exceeded at maximum throughput (unless expressly specified in the documents):

Type of pipe work

max. velocity

Steam lines: High-pressure live steam lines (PN > 64) 60 m/s

Intermediate-pressure steam lines (PN

25140) 40 m/s

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Low-pressure steam lines above 5 bar 35 m/s

Low-pressure steam lines < 5 bar 25 mls

Vacuum lines 80 m/s

Saturated steam Iincs 20 mls

Water lines (Feedll'ater, cooling water, condensate etc.):

Feedwater suction lines 0.5-2.5 m/s**

Feedwater discharge lines 3-5 m/s

Other suction lines 1.5 m/s

Other discharge lines Fuel lines:

3.0 m/s

Coallair lines 25 m/s

Fuel oil suction lines Fuel oil discharge

1.0 m/s

Air Lines: 2.0 m/s

Compressed air lines 20.0 m/s

• The design and routing of the feed water suction lines must be optimized considering the allowable velocity or depressurization caused by load changes.

The following standard pipe sizes shall preferably be used for main process lines: Nominal Diameter in mm: 25, 50, 80, 100, 150, 200, 250, 300, 350, 400, etc.

inch: 1, 2, 3, 4, 6, 8, 10, 12, 14, 16, Pipes with a diameter size smaller than 25 mm (one inch) may be used only for control air, control oil, chemical dosing, scaling water, instrument connections, sampling pipes and other instrument and analysis lines.

For the design of safety valves installed downstream of reducing stations, high pressure bypass valves or equivalent control valves, the maximum throughput of the fully open reducing or bypass valve including injection water quantity is to be taken as the basis for calculation. All cross sections and lines for safety devices that protect against excess pressure (safety valves, rupture discs and similar items) must be designed to ensure the necessary blow-off rate and fault free functioning

All safety valves shall have a test certificate issued by an approved authority.

The design pressure is equal to the response pressure of the devices protecting the piping. In the case of pump discharge lines a pressure corre-sponding to 1.1 times of the shut-off head of the pump at the ambient temperature is to be taken as the minimum design pressure. The main cooling

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water and seawater supply systems must be designed according to . the water hammer calculation.

The design temperature is the highest possible fluid temperature occurring in the length of line concerned. Possible tolerances of the temperature control system and any temperature allowances provided by the requirements of the standards shall be considered.

For live steam lines the design pressure of the boiler shall be taken as the design pressure of these lines up to the inlet of the turbine main stop valves.

In addition to the required wall thickness in accorda'1ce with calculations, a corrosion allowance of 3 mm shall be added for unprotected carbon steel, 1.5 mm for alloy steel, and 0.5 mm by stainless steel.

For the piping systems with a nominal pressure specified as PN > 40 as in DIN 2401, or equivalent, the drainage and ventilation facilities shall be fitted with double valves.

All vents, drains or dump points with more than 10 bar/10000C operating pressure/temperature shall lead to the flash tanks and into funnels at visible points with covers.

Guidelines for the design and construction of pipe work and accessories

• Design and construction of all parts of the pipelines and accessories should correspond to the present state of the art and shall be based on the latest standards.

• The pipe work and its accessories shall be designed and arranged so that all parts subject to operation and maintenance can be operated, inspected,. maintained and replaced without difficulty and with a minimum of effort. All important parts must be accessible.

• Provisions to allow for isolation and for access must be foreseen on all parts subject to acceptance resets by the local authorities.

• The nominal bore of gate valves shall be the same as the nominal diameter of the pipeline in which they are installed.

• None of the forces and moments transmitted by the pipes to connected machines, apparatus and other components must exceed the maximum permissible values, given by the manufacturers of these items. Attachments to turbine foundations shall be carried out only as agreed with the turbine manufacturer.

• All steam traps shall be provided with a bypass and lines which open to a funnel.

• As far as expansion joints and other parts of pipe work are concerned it shall be borne in mind that differential settlement can occur. The reaction forces and moments of the piping system to be withstood by fixed points~ walls, foundations and other dvil structures shall be reduced to the utmost minimum by suitable means (e.g. expansion joints shall be provided where required).

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• Since the steam pipes may be filled with water for a short time (e.g. when flushing or pressure testing), supports shall be dimensioned accordingly. The load information to be given by the Contractor to the civil designers shall take account of this requirement.

• The pipe support structures shall be designed to minimize heat transfer.

• The installed pipe work with its supports and other components shall not obstruct gangways (min. 1000 mm wide), maintenance; escape routes etc. Overhead piping shall have a minimum vertical clearance of 2.3 meters, in pump rooms 2.45 meters and 6 meters above roadways.

• Main pipe ways shall be designed to accommodate 20% more lines than is required for the initial installation. When designing sleeper ways, allow space for adding 20% additional sleeper width.

• Pipe spools for HP steam, feed water piping and all steel pipes > DN 50 shall be cleaned internally prior to delivery by shot blasting (no sand blasting) at the workshop with iron particles to SA2 1/2 or by acid cleaning, and shall be property protected against corrosion.

• Pipe ends and branch connections of underground piping shall be sealed temporarily during installation if the connecting pipe is not immediately installed.

• The Contractor shall submit a detailed description of proposed steam blowing and other cleaning procedures for all pipelines, and no part of this work shall be started until these procedures have been approved by the Employer. Temporary silencers shall be provided for this.

• The Owner/Owner's representative reserves the right to require the Contractor to modify any of his cleaning .procedures if found necessary to obtain acceptable results.

• The contractor shall furnish, install and dismantle all temporary pipes, hangers, anchors, etc. required for cleaning all piping system.

• To the extent that hot fluids can accumulate in pipe sections isolated for maintenance purposes (including control valves with injection water), drains with hand-operated shut-off valves are to be provided for the safety of the personnel (block and bleed systems) . Furthermore the Contractor shall safeguard the piping systems against over-pressurization caused by thermal expansion of blocked-in fluids by adequate means.

• AH welding shall be carried out according to relevant standards. For quality reasons as many welds as possible are to be carried out of the workshop.

• Welding ends of all piping must be carefully prepared before welding. The type of butt welding ends of valves, control devices, orifices, etc. shall be specified by the Contractor and must be given to the manufacturers of these components in due time prior to their start of work if necessary/post weld heating treatment. If there are differences in the wall thickness and/or different materials of piping and valves with butt-welding ends, the necessary transition pieces must be provided by the manufacturer of the valves

• Control valves should have flanged connections.

• Socket welds are not permitted for lines above DN 50, for corrosive media

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lines or for lubricating oil lines.

• After completion of the weld joint, the welder must mark with indelible

crayon his identity number and the last two digits of the year in which the work was completed on the pipes. The Contractor shall keep a record of welders.

• The Contractor shall provide suitable thimbles and flashing where pipelines pass through floors and walls. Floor thimbles shall be installed to provide 90 mm projection above the finished floor surface.

• A flexibility analysis must be performed for all piping systems DN > 80 with an operating temperature > 120°C.

• The piping stress and flexibility analysis shall be based on the relevant standards. Recalculation must be taken into consideration as built condition, actual weight and dimensions.

• Pipe materials, bends and fittings shall be tested in accordance with the applicable material standards.

Pipe supporting elements

Constant support hangers shall be provided at all locations where it is necessary to avoid transfer of stress from that support to another support or to an equipment terminal, and at other support locations where vertical movements of the piping are too large to be properly handled by variable support springs. Constant support hangers shall be of a design that will compensate for the normal variation in the supporting force of the helical coil springs, thus providing constant supporting force throughout a total travel range which shall be at least 20 mm greater than the actual maximum movement of the piping.

The supporting arrangements - if applicable - shall be capable of supporting the weight of the piping systems when full of water during hydraulic testing (see chapter test at site, hydraulic test).

Constant support hangers and spring hangers shall be equipped with a means of locking the springes) against movement during erection, hydrostatic testing etc. The use of counterweights in substitution for support spring assemblies will not be permitted.

Support spring hangers shall be of the enclosed spring type, and shall have an embossed on factory load indication scale showing the hot (operating) and cold (ambient) positions. Each spring assembly shall incorporate an adjustable hanger rod coupling to permit load adjustment. All support springs shall be designed to permit at least ± 10% field load deviation from. the factory calibrated load.

The supporting force provided by variable support type spring hangers shall not change by more than 20% between the cold and hot positions, and supports of this type shall not be used at any point where such a change in supporting force cannot be safely permitted. Variable support spring hangers shall incorporate springs with maximum working range Iength in order to reduce the overall length of the assembly.

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All pipe hangers and support stands shall be attached to the piping and structural supports such that they will be vertical when the piping is at operating condition. So far as practicable, hangers and supports shall be of the same type and component assembly.

All hangers shall be carefully adjusted. After plant start-up checks shall confirm that all hangers and supports are in the correct position. The Contractor shall prepare a complete documentation of a1\ pipe hangers and supporting elements. These documents shall contain the following information:

• identification coding number

• loads, forces and moments, and their directions at all supports, hangers at normal operating conditions, etc.

• magnitude and directions of the movements at the loading points

• measurements of the loading points referred to the axes 'of the buildings

• item No. of the supports, hangers etc. according to the piping group

• material specification for the supporting parts.

All hangers shall be carefully adjusted. After plant start-up checks shall confirm that all hangers and supports are in the correct position.

The Contractor shall prepare a complete documentation of a1\ pipe hangers and supporting elements. These documents shall contain the following information:

• identification coding number

• loads, forces and moments, and their directions at all supports, hangers at normal operating conditions, etc.

• magnitude and directions of the movements at the loading points

• measurements of the loading points referred to the axes 'of the buildings

• item No. of the supports, hangers etc. according to the piping group

• material specification for the supporting parts.

Trace heating

Trace heating shall be provided for fuel oil pipes and other pipes as required.

Electric type trace heating is preferred.

Protection of buried pipe work systems (as far as not installable in ducts)

All buried pipe work of steel or cast iron or other materials prone to corrosion shall be protected from corrosion by catholic protection and a system of tape wrapping to be applied in the workshop.

The design of the catholic protection system(s) shall be executed by a specialist and authorized company under consideration of the following:

• impressed current-type catholic protection systems shall be employed; only if

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the calculated current required is too low may suitable sacrificial anodes be used for protection,

• coating of a minimum finished thickness of 6.5 mm for bitumen or 2.5 3.5 mm for plastic coatings (PVC or PE), applied for tape wrapping spirally with an overlap of 50%, the coated pipeline supplemented by suitable, catholic protection systems,

• suitable insulating joints arc to be provided where systems arc to be separated and, as a minimum, locations where there is a change from above-ground to buried piping,

• the designed catholic protection shall be a completely functioning system in all respects according to the state of the art and shall also include the appropriate equipment for measurements .

0.6.16.4 Welding and heat treatment

0.6.16.4.1 Responsibility

Each Contractor must have the necessary facilities available to ensure that the materials are properly processed and all tests can be carried out.

It must have his own supervisory staff and trained workers for the manufacture.

Each Contractor shall be responsible for the quality of the welding carried out by his organization and shall conduct tests not only of the welding procedure to determine its suitability of ensuring welds which will meet the required specifications and tests, but also of the welders and welding operators to determine their ability of applying the procedure properly. No production work shall be undertaken until both the welding procedure and the welders or welding operators have been qualified.

The Owner/Owner's Representative’s acceptance of welding execution docs not releases the Contractor of his responsibility.

0.6.16.4.2 Required documents

The Contractor shall maintain the/following documents for welding, tests and heat treatment:

• list of welding supervisors

• current log of maintenance, examination, calibration and identification of welding equipment as well as drying and warming equipment for welding auxiliary materials

• instruction for issue and return of welding auxiliary materials their drying and warming, storage and identification

• list of welding procedure qualification including test results (PQR) approved by an internationally recognized authority

• list of qualified welders, documentation of welders' qualification records

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• welding schedule, welding procedure specification

• inspection plan and procedure for testing of weld edges and complete weld

• instruction for handling of non-conformities

• record of performed welding and repairs by welding, their test results and the welder or welding operator who made them

• current log of maintenance, examination, calibration and identification of heat treatment equipment

• heat treatment plan including sketch of temperature measuring points and temperature-time diagram

• manner of temperature control

• members of the unit responsible for the performance of heat treatment

• record of all performed heat treatments

Prior to any work on welding, the above-mentioned documents shall be available to the Owner/Owner's Representative and be subject to review and comments by the Inspector.

0.6.16.4.3 Welding procedure qualification

Each Contractor shall furnish proof in a procedure qualification test adapted to the manufacturing process that he is fully conversant with the welding procedure used.

Supplementary tests will be necessary if the materials, dimensions or jointing methods are changed beyond the scope of procedure qualification test.

The specific data including the test results shall be recorded in a procedure qualification test record and approved by an internationally recognized authority and shall not date back for more than 3 years.

It is permissible for a Contractor to have the welding of the test welds performed by another organization.

0.6.16.4.4 Personnel qualification

The Contractor shall employ his own welding supervisors. The name of the supervisor shall be made known to the Owner/Owner's Representative.

Welding supervisors must be persons who, through their training, experience and ability, arc considered suitable for the job after an adequate job training period.

The Contractor shall only employ welders who have passed a qualification test as stated in DIN or ASME or an approved standard with equivalent i requirements.

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I f not otherwise agreed upon, the tests and certificates shall be valid as per adopted pressure code.

The regular renewal of the qualification of welding personnel shall be done according to the same standard and specification used for their initial qualification. If at any time, in the opinion of the Owner/Owner's Repre-sentative, the work of any welder appears questionable, such welder will be required to pass additional qualification tests to determine his ability to perform the type of work on which he is engaged. All such additional qualification tests and the physical tests on the welded specimens shall be made at the expense or the Contractor and in the presence of the Owner/Owner's Representative.

The sample welds shall be carried out on specimens of similar shape, thickness and chemical analysis as for the material to be welded, and in a position which shall represent as far as possible the worst conditions under which actual welding would take place.

The procedure of preparation of the test pieces, and the standards to be used for the examination shall be in accordance with the relevant standards or as may be agreed upon between the Contractor and the Owner/Owner's Representative.

Each qualified welder and welding operator shall be assigned an identifying number or symbol by the Contractor which shall be used to identify the work of that welder or welding operator.

The performance qualification tests for welders and welding operators conducted by one contractor on ASME base shall not qualify a welder or welding operator to do work for any other manufacturer or contractor.

0.6.16.4.5 Welding process 0.6.16.4.5.1 Welding schedule/welding procedure specification

Each Contractor shall qualify the welding procedure specification by the welding of test coupons and the testing of the specimens according to relevant standards. The record of the procedure qualifications test showing the welding data and test results approved by internationally recognized authority, shall be the basis of a welding procedure specification or welding schedule.

The welding procedure specification or welding schedule shall list in detail:

• the relating Procedure Qualification Record (POR)

• the various base metal to be joined

• the welding auxiliary materials to be used

• the range of preheat

• the heat treatment plan

• thicknesses

• the positions

• the sketch of the joint and number of weld passes

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• welding sequences especially for tank welding and large equipment

• inspection plan and test procedure for testing of weld edges and complete weld.

Prior to start of welding, the welding schedule and test procedure shall be available at workshop respective site.

0.6.16.4.5.2 Welding inspection and records

The Contractor shall maintain and make available to the Owner/Owner's' representative both at works and at Site, adequately indexed records of all welding, weld inspection and tests and repairs.

The extent of the weld inspection, the final weld quality and the method of examination shall be such as stated in

• the relevant standards and codes • the sub-section of this Contract • the test procedure • the welding schedule or welding procedure specification

In case of conflict the more stringent requirements shall be valid.

The Contractor shall also establish a procedure whereby welded joints can be identified as to the welder or welding operator who made them if requested by the Owner/Owner's representative or as stated in sub-sections of the Contract.

0.6.16.4.5.3 Welding auxiliary materials

The requirements of the welding auxiliary materials' manufacturer shall be strictly adhered to.

The Contractor shall prepare written instructions for issue and return of welding auxiliary materials, their drying and warming if required, their handling, storage and identification.

0.6.16.4.5.4 Joint preparation and assembly All joints shall be prepared according to the relevant standards and to the welding schedule,

As far as possible, the preparation shall be carried out by machining. Where thermal cutting is used, the weld edges shall be machined afterwards.

Butt-welding on pipes shall be performed without the use of backing rings. Surfaces to be welded shall be free from oil, grease, foreign matter, corro-sion products and humidity, and shall be free from protective coatings unless permitted by a qualified welding procedure.

Tack welds used to secure alignment shall either be removed completely or their stopping and starting ends shall properly by prepared by grinding and, if required by testing so that they may be satisfactorily incorporated into the final weld.

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Tack welds shall be made by qualified welders only.

The welder's identification number of symbol must be stamped near to each executed welding, where requested by the Owner/Owner's representative or as stated in sub-sections of the Contract.

In order to cope with the requirements for a surface protection suitable for the prevailing aggressive environmental conditions and to' avoid corrosion in crevices, all welded steel works for structures has completely to be seal welded.

0.6.16.4.5.5 Non-conformities

The Contractor shall issue an instruction sheet for handling of nonconformities.

Each non-conformity has to be noted by him. He shall present a proposal of acceptance or removal of the defect to the Owner/Owner's Representative. Every major repair procedure needs the approval of the Owner/Owner's Representative.

If heat treatment has already been performed, the repair documents for approval shall include the heat treatment plan after completion of the repair.

0.6.16.4.6 Pre-heating and heat treatment

0.6.16.4.6.1 Heal treatment equipment

Apparatus and equipment used for heat treatment shall be inspected and checked for correct operation.

The Owner/Owner's representative may ask for the current log of maintenance.

0.6.16.4.6.2 Pre-heating

If pre-heating is required according to welding schedule, the temperature shall be maintained during the welding operation. In case of interruption of welding and preheating, a stress relief heat treatment shall be done prior to the interruption.

In any case, the welding schedule or welding procedure specification for the material being welded shall specify the minimum preheating temperature.

Preheating for welding or thermal cutting may be applied by any method which does not harm the base material or any weld metal already applied or which does not introduce foreign material into the welding area which is harmful to the base material or weld

0.6.16.4.6.3 Heat treatment

Heat treatment prior to and after welding in order to achieve stress relieving shall be applied as specified in the internationally recognized standards and Codes.

The Contractor shall issue a heat treatment plan showing the temperature

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time diagram and a sketch with the temperature-measuring points <Illd describe the manner of temperature control.

Welding after final stress relieving is basically prohibited. The relevant piece shall undergo a new stress relieving process if any welding has been performed afterwards.

0.6.16.4.6.4 Records of heat treatment

The Contractor shall maintain and make available adequately indexed records of all heat treatments performed to the Owner/Owner's representative and inspector both at the works and at site.

0.6.16.4.7 Documentation

The above-mentioned records and instruction sheets and documents re-quested by this Contract or relating standards shall be stored by the Con-tractor during the erection time and shall be part of the general power plant documentation.

0.6.16.5 Valves, Steam traps, condensate drainers, safety valves, control valves

The Contractor shall design and supply all valves and their accessories. required for the safe, efficient and sound operation and maintenance of the plant based on the appropriate standards. They shall comply as a minimum with the design criteria of the relevant piping.

For reasons of plant standardization, the Contractor shall co-ordinate types and makes of all valves in his supply and that of his sub suppliers.

Design, construction, fabrication and testing of the valves shall be in accordance with the approved standards. The stipulations of this section will take precedence if these are more stringent than the approved standards.

All valves shall be suitable for the media and for the service conditions an~ those performing similar duties shall be interchangeable.

All valves shall conform as a minimum to the PN 16 pressure rating.

Basically the following types of valves shall be used:

• globe valves up to and including DN 50

• gate valves ON 80 and above • butterfly valves

DN 400 and above for LP steam and exhaust steam (DN 80 and above for waterlines (cooling water, process water etc.), operating temp. max.180°C

• lift check valves up to and including DN 50

• swing check valves DN 80 and above

• ball valves DN 25 and above (fuel oil, natural gas, compressed air)

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In vacuum service and wherever otherwise necessary to prevent the entry of air, valves shall be provided with suitable sealing facilities. Where applicable, the valves must be suitable for outdoor installation under consideration of the special climatic and environmental conditions of the site.

Unless otherwise agreed, all valves shall be fitted with the spindle in upright position.

All valves shall be positioned so as to be readily accessible for operation and maintenance from permanent floors, catwalks or platforms. Where required, valve spindles shall be lengthened to have the hand-wheel at 'a height approximately 1 meter above the operation level. All underground valves shall be installed in concrete culverts.

All valves shall be closed in a clockwise direction when looking at the face of the hand wheel. The valves shall have rising spindles and non rising hand wheels. Plastic valve hand wheels will not be accepted.

HP and large size gate valves to be opened under differential pressure shall be equipped with pressure equalizing valves (globe valves).

All valves (especially including ball valves) shall be fitted with indicators to determine the valve position. In the case of valves fitted with extended spindles, indicators shall be fitted both to the extended spindle and to the: valve spindle.

All globe valves shall be equipped with throttling cones with parabolic characteristic.

In general, LP safety valves, butterfly valves, ball valves and orifices as well as all control valves shall be flanged. All valves for steam, feed water and condensate, HP safety valves (inlet side) shall have welded ends, corre-sponding to the connected pipes.

Design of valves and materials used must comply with the relevant stan-dards. They must be chosen in accordance with the requirements to be met and to corresponding pipe work .

For limiting hand wheel forces, for control and operation purposes it may be necessary to install gears and drives.

The max hand wheel force of 25 deka Newton must not be exceeded.

All block valves DN 500 arc to be provided with electrical actuators with manual override. The actuators arc to be operated by local control points which can be locked.

Preferably electrical actuators shall be installed. Actuators shall be suitable for fitment to valves and floor-stands with hand wheels for manual operation and provision to switch over from electrical to manual operation and vice versa (see chapter actuators).

For pneumatic or hydraulic actuators similar requirements must be fulfilled. Fail-safe functions shall be incorporated.

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The Contractor shall furnish and install steam traps at each low point. Each steam trap installation shall include a permanent strainer,. upstream and downstream globe valves and a globe valve as free drain. Steam traps shall be supplied with weld ends.

Drain traps shall be provided with inlet and discharge valves, vents and hand-controlled bypasses and, when discharging into a closed header, shall also be provided with discharge non-return valves.

Steam traps shall preferably be of the thermodynamic or bimetallic type with multistage nozzles selected to suit the service conditions. No traps which incorporate internal screens or check valves shall be used unless specifically required.

Each trap shall be sized to provide ample capacity at the minimum working differential pressure, and to open the orifice at maximum working differential pressure.

Condensate drainers such as used on LP saturated steam or compressed air lines shall be of the ball-float type.

All gate valves shall be of the fullway gate type and when in full open position. the bore of the valve shall not be obstructed by any part of the gate. The internal diameter of all valves at the end adjacent to the pipe work shall be the same as the internal diameter of the connecting pipe.

All valves shall have bolted gland stuffing boxes. Screwed glands and bonnets will not be accepted.

Spindle glands shall be of the bridge type. In all cases where applicable, spindles shall have back-scaling seats to allow renewing of the spindle glands with the valve open under pressure conditions.

HP gate valves shall be equipped with self scaling lid covers. The self- scaling lid covers shall be equipped with a safety device at the body with shut-off valve and interlocking system. This system must be approved by the authorities.

All valves of the HP piping systems shall be suitable for pickling.

The valves for live steam, HP feed water and HP injection water shall be made of forged steel. Forged steel or cast steel shall be used for the remaining systems. Valves made of gray cast iron are not acceptable.

Acceptance certificates for piping components and valves shall be delivered to the Owner/Owner's representative for approval.

a) Relief valves shall be installed in the vertical upright position. b) The outlet piping of relief valves discharging to a closed system, such

as a blowdown or Dare header shall be arranged so that the discharge line flows down to the header without pockets.

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c) Relief valves in hydrocarbon service discharging to atmosphere shall have outlet piping extended not less than 3.6 meters above highest working level or 4.5 meters above roof of nearest building within a radius of 12 meters.

d) All relief valves discharging to atmosphere shall have a weephole located at low point, and for hydrocarbon relief valves a steam dispersal line, operable from grade.

0.6.16.6 Insulation

Thermal insulation

The thermal insulation shall be designed and installed in accordance with the chosen standards, considering the following minimum requirements:

• Insulation shall be provided for personnel protection, heat conservation, noise reduction and for prevention of the formation of condensation on all pipe work and equipment whose external surface temperature exceeds 60°C.

• All insulation material has to be made from non-asbestos materials.

All pipes and equipment to be insulated must be indicated on the flow sheet and technical data sheets with the following code letters:

HI = heat insulation

CI = cold insulation

CWI = chilled-water insulation

PPI = personal protection insulation.

Type of insulation materials

The following insulating materials may be used:

Piping DN ≤;250 preformed shape blankets

Piping DN > 250 blankets

The mats shall be stable in shape, chemically inert, free of sulfur and alkali, resistant to water and steam, non-flammable and capable of withstanding continuous exposure to the pipe design temperature. The mats used for insulation of stainless steel equipment shall have a chloride content of less than 0.15%. Under no circumstances may asbestos or asbestos containing materials be used.

The material will have the following physical/chemical properties (± 10% allowance): • service temperature up to 6000 C • density 120 kg/m3

• water adsorption 0.5% weight

• specific heat capacity 0.84 kJ/kg UK

• compressive strength 20 kPa

• conductivity versus temperature

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Average temperature (OC) Blanket (W/m K)

0 0.034

50 0.040

100 0.048

150 0.058

200 0.070

250 0.083

300 0.100

•Conductivity allowance is limited to + 5 %.

The manufacturer's name and the material properties shall be labeled on each package of insulation material.

The insulating mats shall be stitched to galvanized wire mesh using galvanized steel wire. The mesh size shall be approximately 19 mm.

For special purposes such as for turbines, boilers, etc. spray type insulation or insulation brickwork (for example calcium silicate) may also be applied. The special insulation materials shall be stated by the Contractor and their design shall match the overall design and guarantee the requirements stated in the specifications.

Type of insulation setting materials

The surface cladtling shall be made of aluminum sheets specified as "99.5% aluminum grade II24, mill finish surface" in accordance with UNI 9001 or other equivalent standard, manufactured in sheets with the following minimum thickness:

Outer insulation diameter up to 150 mm

Sheet thickness 0.7 mm

Outer insulation diameter up to 450 mm

Sheet thickness 0.9 mm

Tanks and other large equip-ment

Sheet thickness 1.2mm

Tank tops shall be provided with insulation strong enough to support a man's weight.

The sheets shall be secured and connected at the longitudinal scams with at least five stainless steel self-tapping screws per meter run.

Plain sheets for fiat surfaces shall not exceed 1 meter square and shall be stiffened by crimping.

At the longitudinal and circumferential joints, the sheets shall overlap by at least 50 mm so as to drain off the liquid and to trap the liquid in the insulation.

Places at which the metal sheets are penetrated for pipe hangers, thermometer sockets, etc. shall be sealed with funnel-shaped recesses or sheet metal rims.

The seams and penetrations of any sheet metal insulating jacket installed

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outdoors as well as in the boiler and turbine house in areas with risk of water spray etc., shall be sealed against penetration of water by means of a suitable silicon based sealant.

The inside of the aluminum jacket shall be protected against contact corrosion from the wire mesh of the insulating mats by suitable means (e.g. Kraft paper or equivalent).

In the case of pipe insulation thicknesses greater than 60 mm, where insulation blankets are used spacers shall be provided at maximum intervals of 950 nun to ensure a uniform insulating thickness on all sides and a perfectly circular shape" of the sheet metal jacket. The sheet metal jacket shall be supported by support webs (for pipe diameters below 100 nun) and enclosed support rings (for pipe diameters 100 mm and above). If the enclosed support rings are not provided with ceramic spacers, the spacers made of steel shall be insulated with one heat insulation strip in the case of operating temperatures of up to 200°C, and with two heat insulation strips where the operating temperature exceeds 200°C.

To provide protection against contact corrosion, the external circumference of the support ring shall be fitted with heat insulation tape 1 mm thick with two woven edges.

Insulation of furnace and main parts of the boiler

Insulation of up to 80 mm layer thickness shall be applied in one layer, above that in two layers with offset joints and seams.

The mats shall be secured in position by suitable means and stitched to one another by galvanized binding wires of diameter 1.0 mm minimum.

Insulation of flanges, valves and fittings

All flanges, valves and fittings shall be provided with two-piece or multi-part caps made of aluminum sheet of the specified thickness. Each piece or part shall be double jacketed and the various ports shall be held together by quick release clamps or lever hooks to facilitate assembly and disassembly.

All caps of the welded-in fittings shall be made longer by approximately twice the insulation thickness so that the welding seams will be exposed after removal of the cap.

All manholes shall be provided with heavy duty hinged insulated covers wherever possible. Such covers shall be secured with easily accessible clamps.

Insulation or tanks and process equipment:

Tanks and process equipment shall be insulated in the same way as pipes, except that the insulating material shall not be attached by wire but by using strong galvanized steel bands.

Spacers shall be welded to process equipment only if this is essential for satisfactory retention of the insulation. Welding of spacers to process equipment is subject to approval by its manufacturer in writing.

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Insulation for personnel protection

Wherever insulation is necessary only for the protection of personnel, it shall be applied around that portion of the pipeline length or 'to that surface of the equipment that is located within 2.50 m above the passage way floor, or within 1.20 m horizontally to the side or at the end of any floor, platform, walkway, stair or ladder.

Where necessary, drain lines and valves shall be provided with a contact guard of minimum 30 mm thickness against accidental contact, and this shall be installed in the same way as the other insulation.

Where insulation is provided for heat conservation it shall reduce the heat loss to an economic minimum. The maximum heat loss shall be 200 W/m

2 at an ambient

temperature acceptable at 30°C and a wind speed of 2 m/s.

For personnel protection all surfaces with a temperature above 50°C and which are within the reach of personnel shall be provided with protection insulation. The maximum insulation surface temperature shall be 60°C.

Cold insulation

Pre-fabricated block and sleeves insulating pieces made from polyurethane (or equal quality).

Pipes and flanges shall be cleaned and given an external protection; coat of paint to 0.35mm (or equivalent).

Pre�fabricated pieces shall be fitted tightly to the pipes. A self-adhesive plastic foil shall be wrapped tightly around the hard foam shells to serve as a steam seal.

The material and thickness of insulation for the various temperature groups of cold piping shall be as given in the following table:

Temperature

of pipe

Piping sizes mm

Insulation Material and minimum thickness mm

Insulation flange joints

280c to 50 C 100 and smaller

25 thick fiber glass or rockwool

required

if required for condensation

125 and larger

40. thick fiber glass or rockwool

required

Materials and thickness of insulation for piping and equipment outside the building exposed to weather:

The material and thickness of insulation for the various temperature groups of piping exposed to the weather outside of buildings shall be as specified in this article, except that the thickness will increase 13 mm in excess of thicknesses indicated therein.

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Chilled-water insulation

Material: Polyurethane foam or equal 40 to 50 kg/m3. Spacing rings shall be fitted around the pipes at an interval of 800 to 900 mm. Aluminum-sheet covers shall be screwed (stainless steel) to the spacer rings. The overlapping has to be in accordance with specified requirements of this Section. The hollow space between the pipes and metal-cover sheets shall be spray-filled with polyurethane foam or equivalent. .

Cut-outs in the dover sheets for pipe supports shall be sealed with a permanent plastic putty.

Valve and flange connections have to be insulated.

0.6.16.7 Vessels, tanks, heat exchanger

Vessels

All pressure vessels supplied under Contract shall be designed and manu-factured in accordance with the relevant pressure vessel and welding standards and codes.

The Contractor is held responsible for the correct design and dimensioning of the apparatus.

Connections shall be provided for all pipe work, together with connection and tapping points for instrumentation. Manholes, vents, drains, safety devices and any platforms necessary for safe operation and easy maintenance have to be included in design and supply.

If under any operation conditions vacuum can occur in the vessels. they shall be designed for max. pressure and full (= 100%) vacuum.

The welding factor for all vessels is fixed to v = 1.0. The minimum wall thickness should not be less than 10 mm, and an appropriate corrosion allowance based upon the particular material, but not less then 1 mm.

Instrumentation and control equipment shall be provided according to the safe service requirements. A minimum requirement is to equip each vessel with a local level indicator, a temperature and a pressure indicator.

Manholes shall be provided as follows:

1. manhole (minimum nominal bore 600 mm) for vessels of 1.0 meter diameter and above

2. handholes (minimum size 200 mm) for vessels below 1.0 meter diameter.

All nozzles shall be provided with flanges and shall be so arranged that practical pipe connections are possible. The stub length for all stub pipes shall be at least 200 nun, measured from the tank wall to the flange sealing surface. In the case of insulated vessels, the length shall be chosen so that there will be a clear space of at least 100 mm between the cover of the insulation and the underside of the flange. Nozzles of nominal bore DN 50 and less shall be reinforced by two ribs at different planes.

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Nozzles below DN 25 are not acceptable.

For insulated vessels, provisions must be made for fixing and supporting the insulation.

Manhole covers of nominal weight more than 20 kg shall be provided with hinged arms.

All tank internals must be replaceable through the manhole. Prefabricated vessels must as a minimum have a coat of primer applied before transport. They shall be cleaned and internally dry. All openings must be secured closed before transport.

Tanks

Unless otherwise specified, tanks used for the storage of liquid fuels, lubricating oil, raw water, makeup water, condensate, chemicals, etc. and tanks used for mixing and agitation shall be of welded construction, manufactured from mild steel plates of accepted quality and thickness in accordance with the approved relevant standards.

All welds shall be continuous, including welds around internal slays, stiffeners and supports (see also Article "Welding" of this Section V).

All large tanks shall have at least two manholes each of 600 mm inner diameter complete with covers of the bolted type, fitted with a davit for easy handling.

All tank nozzles shall be provided with flanges, if not otherwise specified.

Nozzles shall be provided where necessary for the fitting of instruments, level controllers and piping.

Internal and external protection painting of the tanks shall be performed according to the requirements of this Contract.

Arrangements shall be made for the blanking off or removal of all valves or pipe connections during sandblasting and painting to prevent the ingress of sand or other matter. The protective process shall be applied also to any ferrous or non-ferrous parts mounted inside the tanks.

Heat exchanger I

Heat exchangers are to be designed, manufactured and erected in accordance with the recognized international standards.

Only proven products shall be delivered. No cast iron components are permitted.

It must be possible to install and remove the heat exchangers without undue difficulty. Lifting lugs and eyes and other special tackle shall be provided to permit easy handling. '.

Tubular heat exchangers or plate and frame type heat exchangers are acceptable. Where necessary the tubes are to be protected by impact shields. An adequate number of visual inspection ports is to be provided in critical areas to facilitate condition monitoring.

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Unless otherwise specified; all heat exchanger tubes and casings must be designed to withstand 1.2 times the zero flow pressure of the relevant pump at cold conditions, or 1.2 times of the maximum positive operating pressure, as applicable. The minimum design pressure is 6 bar, and the design shall be proof against full vacuum. The test pressure must be 1.5 times the design pressure.

The heat exchangers shall be designed for the maximum temperature incurred plus 20 K.

Heat exchangers must be capable of continuous unrestricted operation with up to 10% of plugged tubes, and a corresponding factor of conservatism of at least this amount must be used in the design of the heat transfer areas.

Considerable importance will be attached to the ease of cleaning the heat exchangers.

Where any heat exchanger part in contact with liquid can be isolated, and there is a possibility of being heated from the other side, safety valves are to be provided for pressure relief.

Pipes from drains, vents and safety valves are to be grouped together, and routed to easily observable points equipped with covered funnels or to the flash tanks.

The overall design and conception of the heat exchangers and accessories is to be such that they are suitable for the degree of automation envisaged for the individual system.

0.6.17 Electrical equipment and works

0.6.17.1 Standards

In addition to the standards as mentioned elsewhere in this document, the design and manufacture of all electrical equipment shall comply with the latest editions of the IEC recommendations, e. g. the following:

• IEC 34 Recommendations for rotating electrical

machinery • IEC 56 HV AC circuit-breakers • IEC 72 Dimensions and output rating of electrical

machines • IEC 76 Recommendations for power transformers • IEC 79 Recommendations for the construction of

flameproof enclosures of electrical apparatus

• IEC 86 Primary cells and batteries

• IEC 123 Recommendations of sound level meters • IEC 129 AC isolators • IEC 137 AC bushing above 1000 V • IEC 141 Tests on oil-filled and gas pressure cables

and their accessories • IEC 144 Degree of protection of enclosure for LV • IEC 157 LV distribution switchgear - ISC 156 LV

control gear Lighting

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• IEC 162 Lighting fittings for tubular fluorescent lamps

• IEC 214 On-load tap changers • lEC 269 Low voltage fuses with high breaking

capacity • IEC 287 Calculation of the continuous current rating

of cables • lEC 292 LV motor starters

• IEC 298 UV metal-enclosed switchgear and control

gear

In case IEC recommendations do not exist, other national standards at least equivalent to German VDE or British Standards BS shall be applied.

The Contractor shall provide the Owner/Owner's representative with four sets (official, complete, unabridged and in the English language) of all relevant standard specifications according to which the equipment is manufactured.

0.6.17.2 Standard voltages

The following 50 Hz AC voltages shall apply:

• 230 kV for the power feeder from/to the network • 33 kV incoming sub-station for feeding construction power. • 6.6 kV for motors bigger than 150 kW and for power distribution within the plant

• 230/400 V ± 10% for power supplies to small electric power consumers and

motors up to 150 kW, for lighting and domestic power outlets. • 230 V safe AC system for uninterrupted essential supplies to consumers,

where no break in supplies can be tolerated.

The following DC voltages shall apply:

• 220 V DC ± 10% for supplies to emergency users of electricity, inverters and controls

• 26 V DC for automatic, measurement and control systems (the voltage range at the consumer terminals between minimum operation voltage 21 V and maximum operation voltage 30 V must be covered by all 26 DC consumers connected).

The general arrangement of the particular voltage level for each part of the plant within the scope of the Contract' arid the connections of the power supply systems can be seen from the general single line diagram.

0.6.17.3 Climatic conditions

All electrical equipment shall be entirely suitable for the use under the prevailing site conditions (see elsewhere in this document) and be of tropical design with vermin proofing.

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0.6.17.4 Inductive interferences

The Owner may operate wireless communication equipment in the station, inside and outside the housings of all the equipment to be supplied under this Contract. The Contractor shall ensure that all the supplied equipment proof against any signals emitted by this wireless communication equipment.

0.6.17.5 Color code system for switchgear, for local switching measurement-control-signaling cabinets and for mimic diagrams

RAL 7032, pebble-gray shall be applied for all electrical and instrumentation equipment housings.

Color code for indications, push buttons on control cubicles, panels, desks, etc. shall be worked out by the Contractor according to the relevant IEC/VDE regulations to be approved by the Owner/Owner's Representative.

Where the On/ Off function of a push button cannot easily be identified by the location, this will be indicated by a sign “ON”/ “OFF” or “0”/ “1” or by color code as se4scribed above.

Mimic diagrams to be arranged on switchgear cubicles, control panels/desks etc., shall be color coded as follows:

• 230 kV brown similar to RAL 8015 • 132 kV red similar to RAL 3000 • 33 kV green similar to RAL 6002 • 11 kV blue similar to RAL 5015 • 6.6 kV silver similar to RAL 9006

• 400/231 V yellow similar to RAL 1021 • 220/110 V DC violet similar to RAL 4001 • 24/48 V DC pink similar to RAL 3017

• earth black similar to RAL 9005


If not specified otherwise the electrical operational equipment must be designed to meet protection classes stated below.

Switchgear, housings for electrical equipment and electrical equipment itself must be designed at least to:

• Class IP31 if located in air conditioned areas • Class IP54 if located indoors but in non-air-conditioned areas • Class IP54 with additional measures if located outdoors in accordance with IEC

529 and DIN 400050 (general protection requirements for enclosures).

The additional measures shall consist of sunshades, protection covers against

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splashing water and sand, additional sealing, special seawater or acid resistive coating etc., depending upon the particular site conditions.

General diffusing lights in switchgear rooms and lights for figments in. luminous ceilings for offices and control room must be designed at least to class IP32. The lamps for external lighting and halide lights for internal lighting must have protection class IP54.

Electrical operational equipment liable to occasional submersion or operation continuously under water (such as submersible motor-pumps), is to be designed to meet class IP58 protection in accordance with IEC 34-5.

Electrical operational equipment which must be installed in areas exposed to danger from explosions must have the required explosion-proof design appropriate to the flash-point group classification of the explosive mixture as laid down in IEC 79 and VDE 0 170/0 171. Attention must be paid to VDE 0165 with respect to the use of electrical operational equipment in workshops and storage premises exposed to the risk of explosions.

In all rooms and areas where the local and operational conditions and surroundings can lead to the accumulation of gases, vapors, mists or dusts which, in combination with air, form explosive mixtures, the operational equipment and installations to be used iri these circumstances must be of ~ explosion-proof design. All operational equipment must be designed to comply with the class of protection dictated by the ignitable mixture (e.g. compression-proof casing, external ventilation, inherent safety, etc.).

Electrical operational equipment should be located outside rather than inside buildings or other structures exposed to the risk of explosion. Whenever operational equipment has to be installed within areas liable to the risk of explosion, protection against explosion must, in general, be applied wherever explosive mixtures can arise. In this connection, the ignition of explosive mixtures must be reliably prevented by adopting the correct choice of design and construction of the operational equipment and the incorporation of supplementary safeguards where applicable.

Electrical, chemical, thermal and mechanical influences must on no account impair, in any way, the protection afforded against explosion. In particular the high ambient temperatures and the influence of nearby heat sources at the installation point must be taken fully into account.

0.6.17.7 Protective measures

In view of the potential dangers of electrical power, the following measures are required for the protection of life, equipment and materials. Basically, all 'live' parts, i.e. all parts of electrical, operational equipment at an electrical potential above or below earth potential when in operation, and with a rated voltage over 42 V, must be insulated or covered so that they cannot be touched accidentally

In addition, measures must be taken by the Contractor to prevent the occurrence or persistence of excessively high contact potentials on conductive parts of electrical operational equipment (frames etc.) brought about by faults in insulation.

For installations up to 1000 V, voltages over 65 V are considered to be excessive contact voltages. Within enclosed electrical installations, with voltages over 1000

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V, the contact potential shall be according to the values. given in VDE 0141 section 4. (Verein Deutscher Elektroingenieure)

The following rules and regulations are to be observed in carrying out protective measure and in earthling procedure:

• IEC 79 and 364 including VDE 0100 and 0190 for installations up to 1000 V

• VDE 0101 and 0141 for installations above 1000 V.

In areas exposed to the hazard of explosion, the protective measures outlined in VDE 0165 are to be adhered to in the erection and installation or electrical plant and equipment.

Protective measures for installations up to 1000 V

Protection against direct contact

All 'live' parts of electrical operational equipment that can be reached by hand must be protected against direct contact either by means of insulation or through constructional design, position or arrangement, or by means of special devices. If, in the case of enclosed switchgear or control cabinets, access is required in the course of normal operation (e.g. for replacing fuses). protection against direct contact must still be ensured when the switchgear or control cabinet has been opened up.

Protective insulation

Protective insulation is to be provided by means of additional insulation over and above the insulation provided for operational purposes. This measure must prevent the occurrence of a dangerous contact potential.

Use of low voltages as a safety measure

This safeguard applies to all equipment, which is required to operate in metal enclosures, boilers, tanks etc. The operational voltage of tools and lighting equipment must not exceed 42 V AC.

Isolating transformers shall be provided by the Contractor for the purpose of producing the protective low voltage. A separate 42 V system will not be provided.

Connection to neutral

The LV network shall be of the TN type, i.e. the LV neutrals of the 6.6/0.42 kV auxiliary transformers are earthed directly.

Neutralization (protective multiple earthling) is intended to prevent the persistence of an excessively high contact potential on conductive parts of the installation which do not form part of the actual operating circuit. For these purpose an earthed middle conductor (N) (which becomes the neutral conductor N/PEN) is required. An installation is considered to be neutralized when all parts of the installation requiring protection arc connected to the neutral conductor or to a protective conductor (non-fused earthed wire) which is itself connected to the neutral conductor;

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The neutral conductor must be earthed in the vicinity of the particular local distribution transformer, where it serves as the system earth.

The connection of the conductive non-live parts (e.g. consumer enclosures, frames of electrical apparatus) shall be carried out.

• in the case of conductor cross-sections up to 10 mm2 Cu via a protective conductor to the neutral conductor

• in the case of conductor cross-sections from 10 mm2 Cu upward direct to the neutral conductor ...

Symmetrically connected power consumers are to be connected to the neutral conductor (N/PEN), using a four-wire power cable. All unsymmetrical connected power consumers (wall sockets, plug boxes, heating circuits etc.), where the cable cross-section is less than 10 mm2, arc to be connected to a special protective (earthing) conductor which is t<1 run alongside the neutral conductor. Because of the clear demarcation between the neutral conductor, carrying operational current, and the protective (earthing) conductor, which (under non-fault condition) carries no current, NO connection between either N and PEN, or N and earth is permissible beyond the point of separation of the neutral conductor (N/PEJ(J) into PEN and N. Unsymmetrical connected consumers must be connected to four-wire power cable for cable cross-sections equal to, or greater than 10 mm2. The neutral conductor is to be insulated in the same manner as the phase conductors. The use of constructional parts of the switchgear as a neutral conductor is not permitted.

Protective measures against installations over 1000 V

Protection against contact

At least the following measures arc to be taken for all parts that are 'live' when in operation:

• in general areas:

• complete protection from all sides against contact, • protective devices may only be removed by means of tools.

• in electrical rooms:

• protection against contact with 'Jive' parts within reach of personnel, • protection against accidental contact outside the reach of personnel.

• in enclosed electrical rooms:

• protection against accidental contact.

The above-mentioned measures for protection against contact are also to be applied to 'dead' parts of the plant where, in the case of a fault, a dangerous contact potential might arise, however, where the parts must not be connected to the protective earthing system for operational reasons.

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Protection against contact voltages

Protective earthing is to be used as a safeguard against excessively high contact potentials for conductive parts of the installation which do not form part of the operational circuit. Here, all normally 'dead' parts equipment and apparatus shall be earthed if it is possible for them to come into contact with ‘live' parts as a result of faults due to the occurrence of surface leakage paths, arcs or direct connections to a 'Jive' part of the equipment.

In considering the dimensioning of the protective earthing system, the thermal loading and voltages on the earlhing are decisive factor and these should be based on the maximum possible earthing current, which can arise.

The earthing equipment and circuits must be of such proportions, as decided by the Contractor, that the contact potential does not exceed the maximum permissible value of 125 V:

0.6.17.8 Auxiliary equipment

Auxiliary switches

Where appropriate, each item of plant shall be equipped with all necessary auxiliary switches, contactors and mechanism for indication, protection, metering, control, interlocking, supervisory and other services. All auxiliary switches shall be wired up to a terminal board on the fixed portion of the plant. whether they are in use or not in the first instance.� .

Auxiliary switches associated with circuit breakers shall have additionally 2 N.O. and 2 N.C. contacts for spare.

All auxiliary switches and mechanisms shall be mounted in approved accessible positions clear of the operating mechanisms and shall be protected in an approved manner. The contacts of all auxiliary switches shall be strong and shall have a positive wiping action when closing.

Anti-condensation heaters

Each individual enclosure accommodating electrical equipment which is liable to suffer from internal condensation due to atmospheric or load variations shall be fitted with heating devices suitable for electrical operation at AC single phase, of sufficient capacity to raise the internal temperature by about 5 °C above the ambient temperature.

Heaters in motors shall be suitably fixed inside the windings.

Heaters in switchgear/ MCC cubicles. control cubicles. panels. desks. etc., shall be controlled automatically by adjustable hygrostats (setting range about 50-100% relative humidity).

The electrical apparatus so protected shall be designed so that the maximum permitted rise in temperature is not exceeded if the heaters are energized while the apparatus is in operation.

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Heaters shall be connected to a suitable terminal box with main switch and indicating lamp. They shall be placed in an accessible position. All equipment. whether fitted with a heater or not. shall be provided with suitable drainage and be free from pockets in which moisture can collect.

0.6.17.9 Requirements for local cubicles and local housings for e.g. switchgear, control, measurement and signaling equipment

Steel-clad cubicles and enclosures with fixed, integral switchgear and apparatus must be provided.

The switchgear cubicles must be partitioned off and incorporate a bus bar system, the necessary instruments, control switches, switch panels of the individual switch and apparatus chambers. The main bus bars are to be installed on the rear face, topside of the switchgear cubicle in a lockable shuttered compartment.

Connections to switching devices, MCB's fuses etc. are to be made from these bus bars. The lower part of the cubicle will house the terminal 'strips and connecting blocks, the clamps for the cable terminals and if required parallel connection copper straps for the connection of more than 2 cables in parallel. An adequate number of ball studs must be provided within the switchgear cubicle suitable for earthing the main and distribution bus bars as well as the switchgear itself by means of portable earthing and short circuiting equipment (to be provided once per switchgear panel row).

The space in the interior of the cubicles must be divided into a section with 'live' parts, 'live' switching elements etc. and a section with control and measuring equipment. The sections arc to be separated by reinforced sheet- steel. .

Care must be taken that in the event of arcing hot gases will not escape to the front of the cubicles (the operational side).

Ammeters are to be provided on the cubicle front panel for the cubicle feeders and the supply outlets for motors higher than 55 kW or motors of lower rating, but particularly important for the process. A single voltmeter with 4-position voltmeter changeover switch must be provided for measurements of bus bar voltage between each phase and neutral. Measuring instruments should, in general, be square in shape.

All cubicles, cabinets, panels, etc. shall be designed for an ambient temperature of 40°C (outside the enclosure) in non-air conditioned areas. Special precautions shall be taken in the design of electronic devices for protection and control systems housed in the cubicle in order to allow for these conditions.

Heating elements are to be provided generally in each local cubicle or cabinet and shall be humidity controlled.

It must be possible to disconnect power supplies to the cabinets by means of manually operated power circuit-breakers (MCB's).

For easy monitoring and a rapid grasp of the operational state, colored mimic diagrams with the required switch position indicators, apparatus symbols and pilot lamps must be provided in every case on main process cubicles and switchgear cubicles. Lamp test facilities for all signed lamps connected shall be provided. All cubicles shall be provided with the required earthing screws.

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Plastic-insulated, stranded conductors must be used for wiring within the switchgear cabinets, which must be numbered at each end with special tabs so that change by mistake is impossible.

Preferably plug-in type auxiliary relays are to 'be used. Apparatus being sensitive to impact must be protected against shock and vibration.

On completion of hand-over the cubicles must contain at least 15% of fully fitted spare terminal capacity and 15% of spare space for the future installation of extra equipment. It shall be possible to replace indicating lamps on the front panels of cubicle feeders and motor-supply outlets with<?ut isolating the equipment concerned. Further-more the control system must be designed in such a way that lamps operate at less than their rated voltage in order to avoid their being overheated.

Incoming and outgoing cables have to be fixed by suitable metallic cubic glands.

0.6.17.10 Local control points and level control cabinets

General

Any electrical consumer unit, which is not controlled automatically or from the central control room, is to be fitted with a suitable local control cabinet. The local control cabinets arc to be installed in the immediate vicinity of the motor drive to be controlled.

Pump motors, which are level controlled locally, will be given an automatic and manual control. The respective level control cabinets arc to be fitted in the immediate vicinity of the pump motors, gauge glasses or level monitoring instruments.

Local control points are to be provided for all MV motors and important LV motors.

Construction requirements

In general local control cabinets and level control cabinets with plastic casings or cast aluminum housings, resistant to impact, sand, light and seawater, mounted on walls or hot-dip galvanized supporting constructions, are to be provided. Hot-dip galvanized casings will be acceptable.

Protection class must be at least IP 55 (with additional measures if located outdoors). The necessary earthing terminals must be provided for earthing purposes.

The cabinets must be equipped with the necessary mini circuit breakers, fuses, auxiliary relays, power contactors, terminal blocks and cable attachment components.

For motors with pre-selection control (operation/stand-by) operatkin hours counters are to be provided.

The stipulation of clause "Requirements. for local cubicles and local housing for e.g. switch gear, control, measuring and signaling equipment" shall be applied too.

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In hazardous areas, the necessary explosion proof control cabinets and level control equipment must be provided in accordance with IEC 79 and VDE 0165/170/171.

Local control points

The local control points are to be equipped as the minimum requirement with:

• ON button • OFF button • Running lamp • FAULT LAMP • TRIP HEALTHY indication

• Lamp test.

When two motors are installed, serving as operation and stand-by lIlIil, then in addition to a double set of the above items, the following equipment has to he installed as the minimum requiem:

• MOTOR 1 - MOTOR 2 (running motor/stand-by motor)prc-selection switch,

• automatic transfer to the stand-by motor in case of failure of the running motor.

Level controls

In the case of pump motors controlled by levels, in addition to thc level control in each case the MANUAL - AUTOMATIC selector switch and the necessary local points are to be fitted. Control of individual pump motors must be effected as follows as the minimum requirement:

• MANUAL - AUTOMATIC selector switch • level control with maximum and minimum contacts • low level contact on motor – OFF • bottom maximum contact on motor - ON • top maximum contact as warning to the central control room • low-low level contact as pump dry-running protection and alarm signal

to the central control room • local control point with ON and .OFF button, .running and fault lamp.

When two pump motors are installed for the same purpose the control is to be effected as follows, as a minimum requirement:

• MANUAL - AUTOMATIC selector switch • PUMP 1 - PUMP 2 (running pump / stand-by pump) pre-selection switch. • level control with three high level contacts: • first (I): high level contact for pre-selected ON • second (2): high level contact for alann signal to the central control room • low level contacts for pumps OFF • low-low level contacts as pump dry-running protection and alarm signal to the

central control room . • local control and lamps as listed above for local control cabinets, for each

motor.

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0.6.17.11 Terminal boxes and terminal cabinets

In order to minimize the amount of cables and distribution of signals and to centralize connections in the plant, terminal boxes or, wherever necessary, by larger amounts of terminals, terminal cabinets shall be fitted on all the necessary

• cable crossover terminal points • central collecting points for individual analog and binary signals and local

transmitters • signal collecting and distribution points for firc alarm, telephone, loudspeaker

and clock system • central distribution points for local signals.

Terminal boxes and cabinets must at least have class of protection IP 54 and must be equipped with the necessary terminal strips, cable glands and fittings components for the connection of the cables ..

The necessary earthing terminals are to be provided for the earthing of the boxes and cabinets.

In any area subject to the danger of explosion, the necessary explosion protected technical boxes and cabinets are to be provided in accordance with IEC 79 and VDE 0165/0170/0171.

0.6.17.12. Explosion proof equipment

According to the kind of fuels and gases used, the danger of explosions in hazardous locations may be caused by ordinary electrical equipment. Therefore, the installation in such locations shall generally be kept to a minimum with said equipment designed or installed in compliance with the latest issue of lEC Recommendation 79 and the appropriate Articles of the American National Electrical Code (NEC) or the German VDE Standards 0165,0170,0171.

Hazardous locations shall be defined as follows:

• Class 1, Div. 1 locations are those

(1) where hazardous concentrations of inflammable vapors or gases exist continuously, intermittently periodically under normal conditions of operation and maintenance and with normal leakage,

and

(2) where the breakdown or faulty operation of process equipment could release explosive concentrations of fuel and cause a simultaneous failure of electrical equipment.

• Class 1, Div. 2 are those .

(1) adjacent to Div. 1 locations which may occasionally be reached by hazardous concentrations,

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(2) where inflammable volatile liquids or gases are handled, processed, or used, but where concentrations are not normally hazardous, because liquids or gases are handled in close~ systems,

(3) where hazardous concentration is normally prevented by positive ventilation. These locations become only hazardous when the ventilation systems fail.

The design features of electrical equipment and/or circuits to reach explosion proof conditions shall be selected with due regard to the place of installations and the kind of equipment.

The main principles shall be as follows:

• Pressure and flame proof enclosure:

All parts which may ignite a hazardous atmosphere shall have an enclosure of sufficient strength to withstand the maximum pressure caused by ignition of the most inflammable mixture of the gas involved. All necessary joints of such enclosure shall be provided with long fits (minimum 25 mm) and close clearances (equal or smaller 0.6 mm) to cool the escaping flame and to prevent flame propagation to the outside atmosphere.

• Oil Immersion:

The parts capable of igniting inflammable or explosive mixtures shall be immersed in oil to such an extent as to prevent- ignition of explosive mixtures above the surface of oil by means of sparks or hot gases produced under oil.

• Increased Safety:

To obtain an increased degree of safety on electrical equipment special measures should be taken to prevent unpennissible high temperatures, sparks or arcs' inside and outside of the equipment on which they do not occur under normal working operations.

• Intrinsic Safety:

An electrical circuit or part of such a circuit shall be considered as intrin-sically safe if neither during normal working operation nor under fault conditions explosive mixtures are ignited by me~ arcs, sparks or any heat generation.

• Any other approved principle not mentioned above.

All explosion proof equipment shall be of approved 'design and must have undergone type tests according to the appropriate standards. The selection of such equipment with reference to design features and allocation to hazardous groups shall be subject to approval by the Owner/Owner's Representative.

0.6.17.13 Keys and key cabinets

Key interlocked switches shall be provided with a Yale or other approved lock

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for locking in the neutral position. A similar lock shall be provided for each selector switch for Locking the switch in any of its positions.

Approved means shall be provided for locking the cubicle doors, live terminal shutters, etc.

The locks or padlocks shall be coordinated for the different applications and shall be supplied with three keys. A key cabinet at the end of each board shall be provided for storing the keys of that board. All eyes shall have six master keys to open any lock or padlock/supplied.

Each key shall have one identification label fixed above the key hanging hook inside the cabinet.

The cabinet door keys shall be similar and shall be six in number.

0.6.17.14 Electric motors

General

All motors shall be of approved manufacture and shall comply with the requirements of this Contract. They shall be complete with terminal boxes, cable glands and, where specified, with heaters and monitoring instruments. Motors of the same type must be fully interchangeable and shall comply as far as applicable with IEC motor standard dimensions. All AC motors shall be of the squirrel cage type provided with either deep slots or double squirrel cages. All motors shall preferably be from the same manufacturer. The general construction shall be stiff and rigid, no light metal alloy casings will be accepted for motors above the size of 10 kW. All precautions shall be taken to avoid any type of corrosion.

All motors shall be fitted with approved types of lifting hooks or eye bolts as suitable.

Rating

The service voltages of the motors shall be as follows:

• 6600 V, AC 3-phase, 50 cps, for motors above 150 kW • 400V, AC 3-phase, 50 cps, for motors up to and including 150 kW • 220/110 V DC for all motors intended to work on the DC system.

The rating of each motor shall be adequate to meet the requirements of its associated plant. The service factor, being the ratio of the installed motor output to the required power at the shaft of the driven machine at its expected maximum power demand, shall be applied as follows:

Power demand Service factor Up to 1 kW 1.3 More than 1 kW up to 10 kW 1.2 More than 10 kW up to 50 kW 1.15 More than 50 kW 1.1

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0.6.17.14.1 High voltage motors

Constructive features:

The following constructive features shall apply:

a) Climatic protection provisions for mounting in the open in n humid and hot climate. Insulation class F. During operation at rated power of the driven machine, the motor insulation must only be stressed in accordance with the requirements of class B insulation.

b) Motor parts made of iron internally and externally sandblasted and surface-protected.

c) Paint finish resistant to chemicals and seawater. d) Bolts dichromate. e) All joint faces and gaps sealed. f) Anti-condensation heating to be switched into operation when the motor feed

circuit is in the ‘off’ position. Heater supply power 'on' indicting -lamps is to be provided.

g) Special treatment of windings with resin impregnation plus immersion in varnish.

h) Varnish-insulated laminations. i) Pressboard material protected by varnishing. j) Selection of special grade of sealing which are resistant to seawater. k) Totally enclosed fan cooled type. For motor ratings the cooling air available

at the specific location has to be considered. l) Condensation outlets to be provided at the lowest point in the housing.

Design and construction of the 1110tors shall comply with IEC 34-1, 34-5 or VDE 0530 and DIN 40050.

Electric features

The following electric features shall apply:

a) Motor rating to be at least 110% of the maximum required electric power consumption of the driven machine.

b) Continuous delivery. of rated power at voltages of 90 - 110% of the" rated voltage at any frequency between 95% - 105% within the thermal limits of insulation class F.

c) Rated power output at ambient temperatures existing at the particular site of installation and under continuous running conditions.

d) All motors shall be designed as 3-phase squirrel-cage motors suitable for direct on line starting. It must be possible, With 100% residual voltage, to switch them on to a large and stable power supply network without incurring damage or deformation. The motors must still be capable of faultless running up to speed with a voltage drop to 80% of rated voltage and rated loading.

e) Motor starting current must not exceed 5.5 times rated current (referred to motor rating at 40°C ambient temp.). The voltage drop at starting must not exceed 10% at the motor terminals.

f) From the cold state four consecutive starts up to full speed must be possible. The second start must be possible immediately after the first start, the third 20 minutes after the second, the fourth 20 minutes after the third .•

g) A minimum frequency of starting cycles of 1000 per year must be guaranteed.

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h) In general motors must be capable of running without overheating when subjected to three consecutive starts within one hour after having run for an extended period on a voltage of 95% nominal volt-age. Thereby the second start must be possible immediately after the first start and the third 30 minutes after the second start. In individual cases where operation depends on signals from pressure switches or other such sources, then a more severe duty with respect to the frequency of starting cycles per hour shall be necessary and the design of the motors must be carried out accordingly.

Protective features

The following protective\'e features shall apply:

i) High voltage motors must be fitted with measuring points for the determination of slot and bearing temperatures.

Six Pt 100 resistance thermometers (2 per phase, one each utilized for over-temperature warning, the other for over temperature trip) are to be provided for slot temperature measurement, and a double thermocouple or resistance thermometer per bearing must be provided for bearing temperature measurement.

Each Pt 100 shall be connected, potential free, to a terminal strip. The connections to the thermometer as well as the associated over-voltage cutouts shall be brought into separate terminal boxes.

j) Where motors have closed-cycle cooling. Temperature-measuring points must be fitted in the cold air stream.

k) The winding temperature has to be detected with RTD's at high temperature and alarm to be produced. at extra high temperature the motor to be tripped.

l) All motor gaps and joints between it and other units must be scaled , m) Earthing clamps at both sides of the stator have to be provided.

Other features

Terminal boxes

The main terminal boxes on the high voltage side shall be provided with a pressure relief joint for the purpose of reducing the danger of an accident as a result of short-circuits, and shall be fitted with a terminal block suitable for any desired type of connection .

A permanently attached connection diagram shall be mounted inside the terminal box cover. If motors are suitable for only one direction of rotation this shall be clearly indicated.

Terminal boxes shall be totally enclosed and designed, to prevent the ingress of moisture and dust (minimum IP 55). All joints shall be flanged with gaskets of neoprene or similar material. The terminal box shall be scaled from the internal air circuit of the motor.

Cable connecting boxes must be longitudinally divided to facilitate filling of cable sleeves and end caps.

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In case lightning arresters for vacuum type switchgear controlled motors are to be foreseen, they shall be incorporated in the terminal box or in a separate box.

Inside the terminal box an earthing clamp for connection of the cable shield must be foreseen.

The opened terminal boxes must have provision for local earthing to be carried out.

Bearings

Motors smaller than 2000 kW shall preferably be provided with a constant level gravity-fed type oil lubrication system with reservoir and oil breather.

Motors with roller bearings must be provided with a lubricator and lubricant supply regulator fitted with solid brass cages that can be refilled while the machine is running.

The bearings of the motors. must be free from stray bearing currents.

Where sleeve bearings are being used they shall be of the self forced lubricating type. If forced lubrication is required it shall be arranged common to both -the motor and the driven machine and provisions shall be made to ensure lubrication during start-up and shut-down operations without the necessity to start an auxiliary lube oil pump. Self-lubricated bearings shall be equipped with an easily accessible lubrication pot with overflow pipe and oil collecting vessel.

All bearings shall be easily controllable during operation or standstill without dismantling the bearings. The bearings shall further be protected and sealed against dust penetration and oil leakage.

Connections, star-point terminal boxes, etc.

All motors must have the star-point connection brought out separately to terminals.

For all motors with a rating of 2000 kW or above a differential relay for winding protection shall be provided and installed in the associated switchgear. In that case the star-point connection shall be brought out separately to terminals.

The differential current transformers are to be designed to class 5P1 0 with a rating matched to the protection system. The CTs shall be accommodated in the star-point terminal box.

Coupling

The motor shaft halves of the couplings, finish-bored, balanced. and complete with keyways are to be drawn on to the motor shaft and balanced out together with the rotor. A coupling guard will be provided.

Running quality

The running quality must be within the classification of "good" according to the VDE recommendations (VDl 2056 group D), i.e. the vibration velocity must be less than or equal to 1.8 mm/s (rms.).

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Cooling

Air cooling for the motors is the preferred method; where water-cooling is applied, conditioned, treated water is to be used.

Motor air exchanger-circuits should be suitable for the prevailing atmospheric conditions, i.e. ambient temperature,' content of humidity and salt in the air, etc. are to be considered.

Where motors are installed outdoors, a weatherproof design shall be chosen. At least one drilled hole shall be provided at the lowest point of the casing for draining condensed moisture. All MV motors and LV motors of IEC size 132 and above shall be equipped with automatically controlled heating elements for protection against internal condensation of moisture during standstill periods.

Heaters of small motors shall be controlled by thermostats those of big motors by a normally closed contact of the motor starter.

Motors shall have a closed internal cooling air circuit recooled by an external cooling air circuit drawn, from the opposite side of the driving end. MV motors installed in the turbine hall shrill be recooled by water taken. from the service water s)'stem. The air/water coolers shall he arranged in such a way as to give free access for cleaning purposes without dismantling them or the associated C.W. pipes.

Motors installed outdoors and directly subjected to sun radiation shall be rated such as not to overstep the maximum metal temperature of 85°C. Where necessary such motors shall be provided with fabricated steel sun coverings.

Approved means shall be provided to protect motors installed vertically against ingress of dirt, etc.

Reverse speed

If reverse running can occur in the case of equipment driven by a motor (e.g. cooling water pump), the motor must be designed for maximum possible reverse speed.

A reverse rotation alarm and starting-circuit interlock are to be provided to ensure that the equipment can not be started while running in reverse.

0.6.17.14.2 Low voltage AC motors

Constructive features.

The same features as for high voltage motors shall apply. Anti-condensing heating shall be provided for motors of 55 kW and above.

Electric features

All motors shall be designed as 3-phase squirrel-cage motors suitable for direct on line starting.�

The motors must be capable of being-switched on to a large and stable

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network and with phases in opposition.

The electric features a), b) and c) of high voltage motors also apply here. Motors starting current must not exceed 7.0 times rated current (referred to the motor rating and 40°C ambient temp.).

Protective features

An earthing clamp inside the terminal box has to be provided.

Other features

Cable Leads

All cable connecting boxes are to be designed to meet the requirements of IP 55 or IP 58 protection class respectively.

The cable connecting boxes are to be installed easily accessible on the motor. The connecting boxes .must be capable of being turned by 900 or 1800 and of being opened up longitudinally. The connection boxes are to be filled with a terminal block.

Bearings

Maintenance-free bearings are to be provided for motors up to 37 kW rating at least. All motors utilizing maintenance-free bearings must be clearly and permanently indicated as full. All other bearings must be provided with a lubricator that can be used while the machine is running. Over-lubrication must be avoided by means of a lubricant controlling device.

Motors installed in inaccessible locations must ha'{c lubrication connections piped to accessible locations.

The motors are to be provided with roller bearings (i.e. groove ball or cylindrical roller type). The motors must be free from stray bearing currents.

Cooling

The corresponding requirements of high voltage motors apply.

Shafts

Where not otherwise specified, motors must be filled with a free shaft end

0.6.17.14.3 Actuator drives

All actuators for valves, dampers etc are to be fitted with socket and plug of well-established make to IEC 309, VDE 0620, CEE 17 or equivalent for the power cable connection. For the control cable connection separate socket and plug shall be provided.

Self-cooling at respective ambient temp. Conditions is mandatory. Fan cooling is not accepted

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0.6.17.14.4 DC motors

As far as possible the use of DC motors is to be avoided and must be agreed by the Engineer. The max. starting current must not exceed two times of the rated motor current (referred to the motor rating at 40°C ambient temperature).

DC motors shall be capable of operating continuously under rated output conditions at any voltage between 90% and 110% of the nominal voltage. Unless otherwise approved the speed drop between no-load and full-load shall not exceed 10% of no-load speed. All DC motors shall operate with a fixed brush setting for all toads.

Brush gear for DC motors shall be designed to ensure constant brush pressure. Carbon brushes shall be provided which stand at least six months of operation without replacement. Each brush shall be independently adjustable but shall not require adjustment" throughout its life.

The brush holder shall not touch the commutator as the brushes wear and current carrying through the pressure fingers will not be accepted.

A sufficient number of brushes, not less than two per pole, shall be fitted to ensure that vibrations do not effect the commutation.

The minimum safe wearing depth of commutators shall not be less than 6 mm and the minimum safe diameter shall be marked on them.

0.6.17.14.5 Painting

All motors, whether for outdoor or indoor installation, shall receive a coating of paint which is resistant to sea water and corrosion.

All internal and external steel parts of the motors must be sand-blasted and impregnated. Following this, a paint finish resistant to chemicals and seawater must be applied. The' bolts used must be chromated at least.

0.6.17.14.6 Protection against explosion hazards

Low-voltage motors, which arc to be installed in areas exposed to the risk of explosion, must comply with the rules laid down in VDE 0165/0170/0171 for explosion-proof design in relation to the flash-point group classification for the particular explosive mixture.

0.6.17.14.7 Frequency converters

General

On the basis of the requirements of the driven equipment, the Contractor will design, supply, install and commission a complete, fully operative, variable-speed converter drive (frequency converter and motor, for motors up to 400 kW, for motors 400 kW and above in addition to the converter a converter transformer wiII be provided) .

Converters made by reputable manufacturers are to be used.

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Technical requirements

The design of the converter (maximum continuous rating) is to be based on the maximum shaft output required by the equipment assembly.

The converter should operate in two-quadrant mode.

Indirect converters with a constant indirect voltage are to be preferred to types with a constant indirect current. Power should be supplied to the converter cubicles from below. If possible, the DC link reactors should be integrated in the converter cubicles.

Maintenance work and cable connections must always be possible from the front of the converter cubicles.

The terminals on the input and output sides are to be rated. such that parallel cables can be connected.

The converter allows the speed of three-phase asynchronous motors to be adjusted steplessly. It must be fully equipped for remote control and monitoring in the control room.

An on-load disconnector and a power contactor are to be provided at the power input of the converter.

For motors with a rating lip to 400 kW the frequency converter shall be designed in at least a six-pulse circuit on both the line and motor sides.

For motors with a rating above 400 kW the converter should be designed in a 12 pulse circuit supplied via converter transformer.

In the case of a current converter, the line rectifier is to take the form of a line-commutated, fully controllable three-phase bridge. A self commutated, fully controllable three-phase bridge is to be provided for the inverter on the load side.

In the case of a voltage converter, the line rectifier is to take the form of a fully controllable three-phase bridge. A self com mutated three-phase bridge with turn-off thyristor branches is to be provided for the inverter on the load side.

The line rectifiers are to be designed for a braking current which is at least 85% of the motor rated current.

The converter is to be disconnected if the voltage drops to less than 80% of the rated voltage or if one or more phases of the line voltages are missed. When the line voltage is restored, the converter is to be connected again automatically, providing the break in the power supply did not last longer than five seconds. The plant check back signals (floating change-over contacts) must continue to be received during this period, while alarms are to be suppressed. It must be possible for the converter to be connected at .any coasting-down drive speed and with in-phase voltages. The specified frequency set point is to be resumed automatically.

If the voltage reduction or the power failure lasts for a long time, the drive must

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remain switched off; in this case, it must subsequently only be possible to switch it on again either manually or by means of the higher order control.

The converters arc to be designed for 10% more than the maximum power output required by the system. The purpose of regulating the converter is to ensure that the indirect current and voltage remain within the permissible limits during all control processes. This should apply both when the motor is started up and when the speed �is adjusted during operation.

All thyristors and diodes arc to be protected by means of semiconductor fuses. The fuses are to be arranged upstream of the semiconductors.

The reactors in the DC link should smooth the DC current and limit the current rise in the event of a malfunction.

Forced ventilated converters are to be equipped with redundant" fans (two double fans).

Flow monitors (not air vanes) are to be used to monitor the fans. Positive control is to be provided for fan drives with a master drive.

Converter transformers

The converter transformers for supplying the frequency converters are to be designed and the auxiliary equipment to be provided in accordance with IEC 76.

The transformers are to take the form of cast-resin transformers and arc to be installed in protective casings made of sheet steel, cooling method AN, type of protection at least IP 21.

The transformer output shall correspond to the power requirement of the frequency converters.

It should be possible to vary the high-voltage side within a range of 2 x ± 2.5%, by means of reversible clamp connectors.

The connections on the high-voltage side have to be carried out using cables.

Bus bar connections with short-circuit protection arc to be provided �to the current converters on the 100\'-voltage side.

Suitable earthing studs are to be provided for maintenance purposes (earthing and short-circuiting) .

All accessories - especially sensors and terminal connections - must be arranged so that they are readily accessible.

The windings must be flame-retardant and self-extinguishing. The cast-resin mixture must not contain any flame-inhibiting additives which develop toxic vapors or gases either under the influence of secondary fires or in the electric arc.

A moisture-proof design will be provided. It will not be necessary to dry the

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.winding after shut-off periods. The protection against voltage surges and short circuits, the noise levels and the freedom from partial discharges up to twice the rated voltage will be verified by means of type tests.

The windings are to be protected by means of a temperature monitoring system, comprising the following minimum components: • 3 PTC resistors (1 for each phase) • 1 tripping unit with isolated change-over contacts for remote signaling

(alarms).

The equipment types are to be agreed with the client in the event of an order being placed.

All the lines belonging to the protection and monitoring systems are to be applied to a transfer terminal strip as individual signal lines.

Instrumentation and control

The instrumentation is subdivided into a local section in the converter cubicle and into a "remote" section in the control room. All the measures necessary to enable the drive to be remote-controlled and remote-monitored must be implemented, i.e. all the 24 V DC interposing relays which are required to convert the on/off commands from the instrumentation and control system, signal transducers, etc.

A suitable automatic compensation facility is to be provided, to ensure that the transfer between LOCAL mode and REMOTE mode is bump less in both directions. The emergency shutdown function of the equipment must act on the converter directly, regardless of whether 'local' or 'remote' mode is set.

Local instrumentation and control.

The following are to be provided as a minimum in the converter cubicle:

Controls a) local/remote converter control (key-operated switch) b) "on" and "off' converter controls c) set point adjuster (speed) d) incoming master switch, "on-off' e) all the controls necessary for internal converter settings and adjustments,

as specified by the manufacturer

Indications, signals, monitoring a) line voltage indicator b) output frequency c) output current d) operating status signals, in accordance with the specifications of the

instrumentation and control supplier, though at least "Ready", "Drive running” and Zero and set speed reached “

e) motor temperature monitor - alarm Motor temperature monitor - shut-down

f) signals concerning internal operating states of the converter, in accor-

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dance with the manufacturer's standards, though at least: • over temperature • line voltage monitoring • line under voltage • over current • control voltage monitoring • converter protection • fan monitoring • incoming air temperature • motor feeder interruption • motor feeder short circuit • earth fault • motor blocked • other faults

Remote control and remote indications

Account must be taken of the following types of remote control and indica-tion in the control room, and suitable interposing relays, transducers and switchgears are to be provided in the cubicle:

a) converter "on/off' and "local/remote" b) set point adjuster for speed (4 - 20 mA) c) remote indication for speed as 0/4 - 20 mA standard signal d) motor current as 4 - 20 mA standard signal e) combined fault f) remote indication of the set speed potentiometer as a 0/4 - 20 mA

standard signal g) other controls and indications

All event signals and check back signals must be made available on the terminal strip as floating change-over contacts

System perturbation

The perturbation caused by the voltage harmonics in the feeding three-phase system, which are a result of the converter drives, must not exceed (he \ specified limit values, i.e. 5% for the 5th harmonic voltage, 4% for the 7th and 2% for each of the 11th and 13th. IEC 801.1 - 801.4 are also to be observed in this connection. The system perturbations are to be curbed by means of suitable measures if necessary. The contractor is responsible for demonstrating conformance with the above-mentioned limit values.

0.6.17.14.8 Motor list

The motor list will be issued by the Contractor shall include all aggregates driven by electrical -motors (except final control elements as control valves, dampers, etc.) and shall contain at least the following technical data:

• item and code no. • location • manufacturer and catalogue no. of motor and driven machine

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• design speed of driven machine • kind of operation (continuous, intermittent, for start-up only) • type of motor construction, cooling, and protection • actual service factor • electrical design data e.g. nameplate rating, rated voltage, rated speed,

rated current, power factor, efficiency, ratio of starting to rated current, ratio of pull-out to rated torque

• other electrical data e.g. starting time at maximum opposing torque, frequency of permissible starts (for motors above 10 kW only)

• driving end and non driving end bearings: manufacturer, type and type number, size.

0.6.17.14.9 Tests

Each motor shall be factory tested and shall undergo a test at site. The following tests shall be performed under full responsibility of the Contractor:

Workshop tests

• measurements of winding resistances (*) • no-load and short-circuit measurements (*) • efficiency measurement (type test) • heat test run (type test) • dielectric test (*) • measurement of insulating resistance (*) • over speed test (*)

(*) may be type tests for motors of final control elements

At motors rated 100 kW or higher in addition:

• measurement of motor vibrations • measurement of starting current and torque (type test) • air gap measurement (type test) • measurement of noise level (type test).

Tests at site

• measurement of insulation resistance • measurement of motor vibrations.

At motors rated 100 kW or higher in addition:

• measurement of starting period.

0.6.17.15 Labels

General

The proposed material of the labels, the size, the exact label inscriptions as well as proposals for the arrangement of the labels shall be submitted to the Engineer for approval. Where applicable, Bengali designations shall appear above or to the

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right of the English designation. The Bengali translations and writings shall ,be readable Bengali and samples shall be submitted beforehand for approval.

Equipment labels and instruction plates

Labels written in English shall be provided for all instruments, relays, control switches, push buttons, indication lights, breakers, etc. In case of instruments, instrument switches and control switches, where the function is indicated on the dial plate or the switch escutcheon plate, no label is required. The label shall be fixed close to the instrument in such a way that easy identification is possible. Fixing on the dial glass of instruments will not be accepted. The wording shall conform to the wording used in engineering documents and shall be submitted for approval to the Owner/Engineer.

All construction units shall be identified by their plant identification number. Cubicles and similar units shall also bear this identification number on the rear side if rear access is maintained.

All equipment inside cubicles, panels, boxes etc., shall be properly labeled with their item number. This number shall be the same as indicated in the pertaining documents (wiring diagrams, equipment list, etc.).

Instruction plates showing in l3angali and English the sequence diagrams or cautions for maintenance shall be fitted on the inside of the front door of the electrical switchgear.

Each separate construction unit (cubicle, panel desk, box, etc.) shall be provided with top mounted labels made of anodized aluminum with black inscriptions giving the overall designation in Bengali and in English.

Warning labels

Warning labels shall be made of synthetic resin with letters engraved in Bengali and English.

For indoor circuit breakers, starters, etc., transparent plastic material with suitably contrasting colors and engraved lettering shall be provided.

L V switchgear shall have yellow labels with 5 cm black letters reading "MAINS 400 VOLTS" .

MV switchgear and transformers shall have red labels with 7.5 cm white fetters reading "DANGER 400 V or 6600 VOLTS".

All switch room door labels (lettering as before) shall be as follows:

• 400 volts mains -Yellow label with Black letters

• 6600 volts mains - Red label with White letters

• DC battery supplies -White label with Black letters

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Labels for conduits, etc.

The material shall be non-corrodible and the inscription be done with 4 mm high letters/ciphers.

Labels for cables

Each cable when completely erected shall have permanently attached to it at each end and at intermediate positions as may be considered necessary by the Owner/Engineer, non-corrodible labels detailing identification number of the cable, voltage, and conductor size.

The cable identification numbers shall comply with those of the cable schedule.

All cables in cable pits and at entry to building blocks shall be labeled utilizing the aforementioned type of label.

Nameplates

Equipment (machines, transformers, etc.) nameplates shall be either of the enameled type or be of stainless steel covered after stamping with a trans-parent paint. .

0.6.18 Instrumentation and control

0.6.18.1 Measuring units

All instruments shall be calibrated and inscribed in the metric system. No other measuring units than the following ones shall be used for the measured variables.

• bar for pressures of steam, water, oil, compressed air and high pressure gas

• mbar for combustion air, flue gas and low pressure gas

• °C for temperatures

• mm or m for levels

• µS cm-1 for conductivity

• rpm for rotating speeds

• % for positions

• Nm3/h for combustion air and gas flows

• t/h for steam and water flow

• % Vol. for flue gas analys6s

• µm or mm/sec for eccentricity and vibrations

• mm for differential and absolute expansions

• cps for frequency

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• A,kA for currents

• V,kV for voltage

• MW, kW for active power

• MVAr, kVAr for reactive power

• Wh, kWh for active energy

• V Arh, kVArh for reactive energy

0.6.18.2 Sizes of indicators, recorders, etc.

-The indicating instruments and recorders shall have the following or similar sizes Indicator on local control panels and MV and LV switch-gears

144 x 72 mm or 72 x 72 mm

- Indicators on vertical section of control desks < in control room and on rectifier or converter panels

96 x 48 mm or 96 x 96 mm

- Indicators on horizontal part of control desks in control room

48 x48 mm

- Indicators on control panels in control room

72 x 72 mm or 144 x 72 mm or 144 x 144 mm or 96 x 48 mm (when incorporated in mimic diagrams)

- Recorders: 144 x 144 mm (for line and 6-point recorders) 288 x 288 mm (foI' 12-point recorders)

- Pressure gauges and other dial type instruments (locally):

preferably 160 mm diameter

The control switches, adjusters, etc., on the panels and desks shall harmo-nize with the above mentioned indicator sizes.

0.6.18.3 Protection and safety interlocks

To protect individual units or parts of the power plant, interlocks are to be formed in accordance with process criteria, which can be either active or passive depending on their functions.

Active interlocks shall automatically disconnect units or parts of the power

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plant before they reach a critical operating condition or shall start certain units (e.g. stand-by) in order to avoid a critical operating condition. In addition, such dangerous conditions must be immediately indicated to the operating personnel by means of an alarm.

Passive interlocks are intended to prevent operational errors or wrong commands from being carried out in the event of selective faults in the automatic control.

Active and passive interlocks must not be capable of being switched off operationally from the central control room. All protections have to work fully automatically and independent of the operator and always have to be effective for all procedures (manual, partial automatic, fully automatic).

After a stop or close action by protection, the restart of the equipment shall be possible only after the fault is rectified and the protection signal is reset. Simple cancellation of protection signal by start command shall not be possible. The protection action and the operator reset shall be recorded by the DCS.

0.6.18.4 Special local conditions

Due to the high humidity special measures shall be considered for the I&C equipment.

• All local indicators shall be of stainless steel.

• All impulse/sampling piping shall he of non corrosive type (e.g. stainless steel. copper. plastic).

• All copper pipes - except installed inside buildings - shall be protected with an external plastic sheet.

• All external screws of transmitters etc shall be of non-corrosive material.

• All secondary shut off valves equalization valves and drain blow-off valves shall be of the non-corrosive type.

• All metallic instrument piping must be protected with corrosion protecting painting.

• All I&C equipment exposed to sun must be protected against direct sun radiation. This may be done by sun roofs. protection casings. etc.

• All multicore I&C cables (with more than 7 cores) outside the buildings shall be covered completely by means of closed cable trays flexible conduits. etc. The individual cables from the terminal boxes to the instruments shall be protected as far as practicable. The cable direct at the instruments connection must only be protected, if exposed to direct sun radiation

0.6.18.5 Tests

The single components and pre-erected assemblies shall undergo functional and routine tests in the Contractor's or Sub-Contractor's workshop. The ready mounted control and supervisory system shall undergo functional tests on site prior to pulling the plant under steam. These tests shall take place in the presence of the. Owner's and Engineer's

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representatives. Besides. all equipment shall be tested in compliance with the prevailing lEC standards and recommendations.

The Contractor shall submit to the Engineer acceptance test certificates on ail tests carried out in the workshops. The results of site tests shall be laid down in reports to be written by the Contractor and signed by the Engineer.

Calibration tests arc to be witnessed on all important pressure gauges and other instruments as required by the Engineer.

0.6.18.6 Field equipment

0.6.18.6.1 Measuring systems/transmitters ;./

Only electric measuring signals of 4-20 mA shall be transmitted to the DCS.

Generally 2-wire transmitters shall be used. If for some special purposes (e.g. analyzers) 230 V AC power supply is required. the output circuit shall be isolated.

As far as possible. all transmitters shall be of the SMART-type. This applies also to field-mounted temperature transmitters.

Thus. only sensors, transmitters and converters with electrical output shall be provided. The output signal of transmitters shall be linear and over a wide range independent of the burden in the output circuit.

Transmitters with accuracy class 0.5 or better must be used. The repeatability shall be within a range of ± 0.1 % of full span.

The removal of connected devices must not open the transmitter output circuit or cause malfunction of this circuit. In the case of failure and return of the supply voltage within a measuring circuit. no false signals endangering the system shall be issued. All transmitters shall be individually fused.

The components shall quickly respond to any changes of the measured variables. Measuring errors shall be as low as practicable. Measuring ranges of indicators, transmitters, etc. shall be selected in such way that the rated value of the variable covers approximately 75% of the span.

Diaphragm seals shall be provided to serve as a barrier for corrosive process fluids, slurries or highly viscous oils. The seal shall be of the flanged type, suitable for the same conditions as those for the transmitter. The material selection shall be according to the requirements of the fluids to be measured. The seal shall be provided with a flushing connection.

Transmitters to be used in hazardous areas shall be explosion proof. Suitable intrinsically safe circuits arc to be provided in accordance with DIN EN 50020.

All transmitters potentially subjected lo vacuum shall be capable of withstanding 100% vacuum without damage.

No stress shall be imposed through the connections between process equipment and the transmitter; As far as possible. the transmitters shall be grouped together

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into enclosed racks or panels for easy access. Sunshades shall be provided for all outdoor panels

Individually installed transmitters shall have their own weather proof enclosure of robust construction "nu be suitable for the proposed environment. All field equipment terminals shall be wired to a terminal box using screwed connections.

Transmitters shall be provided with all necessary isolating, vent and blow down valves and facilities shall be provided for the connection of test instruments at the input and output of each transmitter, to enable calibration to be carried out.

All control, measuring and supervisory equipment (including actuators) related to the explosion-prone areas shall be of explosion proof, e.g. intrinsically safe design.

0.6.18.6.2 Flow measurements

The primary elements of flow meters shall be standard orifices and standard nozzles unless otherwise specified.

Their design and performance shall be in accordance with the before mentioned Standards.

The throats of flow metering nozzles and orifices shall properly be protected against erosion by means of stellite lining or equivalent means. In case of Reynold numbers below 100,000 quadrant nozzles or double tapered orifices shall be provided.

Primary elements such as orifices or nozzles located in steam or high pressure feed water pipes shall be of the weld-in type. Material, dimensions and installation of orifices, nozzles and tapping points etc. shall be in accordance with the specification for the pipes in which they are installed.

Isolating valves shall be provided at the tapping points of the orifices/ nozzles. In the case of steam flow measurements condensing vessels (steam traps) shall be provided between the tapping point and the isolating valve.

In case of flow measurements for fluids with pressures higher than 25 bar double shut-off tapping valves shall be installed. The design and arrangement of tapping point, piping and valves should be according to VDI/VDE rules 3512 Bl.1 or equivalent standards.

The material and dimensions of the piping shall conform to those laid down for the piping concerned. The welds shall be executed in such a manner as to avoid turbulence them can affect measurement.

In order to achieve exact installation, the vendor supplying the orifice plate or nozzle for high pressure pipes shall install the orifice plate or nozzle in its own works in a section of pipe of about 3.5 times the pipe diameter (1.0 x Nil in the outlet, 2.5 x Nil in the inlet). For orifice plates or nozzles installed in pipes with a nominal bore smaller than 80 mm, complete meter runs shall be supplied.

Orifice plates and nozzles shall be manufactured of ANSI 316 Stainless Steel unless specified otherwise.

Orifice plates shall be sized for a d/D ratio not less than 0.20 and not greater than

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0.70. Higher other than lower d/D ratio are preferred to minimi7.c line restrictions. All sizing calculations shall be submitted to �the Engineer for approval.

Tags on orifice plates shall be stamped with the basic design information (i.e. flow rate, pressure and temperature of the passing fluid, the orifice diameter and the pressure differential generated).

Venturi tubes shall only be considered when operating economy requires low permanent pressure losses. Rectangular venturi tubes may be considered where other measuring devices are impossible or impractical (e.g. in large rectangular air duct of boilers). For flow measurements in LP-systems e.g. water or condensate, orifice plate installation using slip-on orifice flanges shall be provided. All ori1icc plates for installation between flanges shall have their own tapings for differential pressure measurements incorporated in the plate. simple orifice plates with the tapings situated in the pipe arc not allowed. The flow direction shall be consistently marked on the orifice or nozzle by means of an arrow. Steam, gas and air flow measurements at measuring points with variable temperature and/or pressure should be provided with automatic correction of flow signal. All flow transmitters shall begin to measure correctly at a rate of flow of at least 5% of the measuring range. The error limit shall be limited to ± I % f~ a rate of flow higher than 10%. The error of the primary elements is not included in this accuracy. The root extraction of flow measurements shall be effected electrically within the transmitters.

All flow transmitters shall be in accordance with Chapter B06.18.6.1 Special conditions may dictate the use of devices such as: • venturi tubes for low pressure gases • pilot tubes such as Annubar

For the measurement of fuel oil flow, turbine type meters or positive displacement meters shall be used.

Magnetic and ultrasonic flow meters may be used under special circumstances but prior to their" use agreement must be obtained from the Engineer.

• Arrangement of flow measurements The arrangement of the throttling devices, e.g. the straight length upstream and downstream from the throttling device shall be according to Standard DIN EN ISO 5167-1. Bends shall be at a sufficient distance upstream from the throttling device, particularly when large orifice ratios are used.

When the requirements of the Standards cannot be fully complied within some cases, then, as an exception, an uninterrupted pipe run of at least lOx Diameter

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(D) length should be provided, with 8 D located upstream, and 2 D downstream from the measuring point. The said exception is subject to special approval by the Engineer.

0.6.18.6.3 Temperature measurements

All temperature measurements shall generally be carried out with protective wells, where applicable.

Wells of the screw-in (NPT-connection) put-in type shall be restricted to measuring points for lubrication oil, dematerialized water, air, gas, cooling water and flue gas, and to such measuring points where welding is 1I0t suitable, e.g. at cast-iron parts. All other protective wells shall be welded to the pipe. Thermometer wells shall be covered by screwed caps for protection during transportation and creation.

Gastight ceramic inside tubes shall be provided in addition to the outside protective tube for temperatures higher than 650°C.

Resistance and thermocouple thermometers shall be equipped with weather proof connection heads. These thermometers shall be arranged in such a way that the connection heads do not become warmer than 100°C, and that the measuring inserts are easily exchangeable.

The temperature sensors shall be selected in such a way, that only a small number of different spare inserts is required.

Resistance thermometers shall generally be of type Pt 100 and shall not be applied for measuring values above 450°C approximately Double resistance thermometers (with two resistors in one insert) should be used.

For resistance thermometers 3 wire circuits shall be applied principally. Depending on the operating temperature the following thermocoup2es shall be used:

• Fe-Constantan for temperatures up to 700°C

• NiCr-Ni for temperatures up to 950°C

• Pt Rh-Pt for temperatures higher than 950°C

Thermocouples shall be connected to reference junction devices by means of suitable compensation leads. The wiring from the reference junction boxes to the receiver may be normal cable (multicore cable).

Locally mounted temperature transmitters shall be used for remote indication and functions. Head mounted temperature transmitters may also be used. All temperature transmitters shall be in accordance with Chapter B0.6.18.6.1.

Where more than one temperature measurement e.g. recording. indication. automatic control is to be made at one location. individual protective wells with sensors shall be provided at the common place of measurement. Protective wells for unoccupied test measuring points and shall be arranged with the opening inclined downwards wherever possible and shall be provided with a screw-on protection cover.

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The use of dial type contact thermometers shall be restricted to bearing metal only. In all other cases thermocouples or resistance thermometers and electronic limit switches shall be used. Glass thermometers or similar will not be accepted as contact thermometers.

Insofar as local conditions or extreme temperature do not require otherwise. Screw-in immersion wells for exhaust gas and air shall meet the following requirements:

• nominal length not less than 0.5 m • the attachment of the well in the wall of the exhaust gas channel or air duct

must be gas-proof.

For the measurement of temperature of other media the following requirements shall be observed:

For all pipe work a minimum immersion depth of 55 mm in the internal pipeline cross-section and a minimum distance of 15 mm from the opposite pipe wall must be provided. If the diameter of the pipeline does not allow the thermometer to be inserted perpendicular to the pipe axis while still maintaining the above mentioned measurements another solution must be found in cooperation with the Engineer.

When determining the lengths of the insertion and connecting tubes the insulation thickness is 10 be taken into consideration.

0.6.18.6.4 . Pressure measurements

Pressure gauges shall be shock and vibration proof (preferably by filling with glycerin). They shall be made as far as possible of stainless steel. Pressure gauges for steam and gas shall have safety properties according to DIN 16006 or equivalent.

Over ranging the measured pressure shall not deteriorate the pressure gauge nor affect its calibration. The pressure gauges shall be equipped with a radial connecting stud, to allow the mounting on a gauge holder.

Pressure gauges with potentiometers will not be accepted for use as a pressure transmitter.

Pressures to be remotely indicated, recorded or used for automatic control loop inputs shall be measured by means of pressure transmitters (refer to Chapter B0.6.18.6.1).

Each gauge, pressure switch and transmitter for absolute or differential pressure shall be equipped with a pressure gauge isolating valve including a test connection of the screwed type M20 x 1.5 mm. This isolating valve shall be located directly at each gauge, pressure switch or transmitter. If the gauge or transmitter serves for control, interlocking, or alarm purposes, the shut-off valve shall have separate shut-off devices for both the instrument and the test connection.

Pressure transmitters may not be directly mounted on the pressure tapping point. They shall be mounted apart from the tapping point. Whenever possible,

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transmitters shall group wise be combined on racks or in cubicles (in open area). In case of flowing substances, the tapping point shall be selected in regions of undisturbed flow.

The design and arrangement of tapping points, piping and valves shall be according to VDI/VDE rules 3512 Bl 3 or equivalent standards.

Pressure measurement tapping points shall generally be in accordance with the specification for the pipeline in which they are installed and shall be equipped with one, and, for high pressure installations (> 25 bar) two, isolating valves arranged directly at the tapping point and having a nominal bore of at least 15 mm (1/2"). Excluded from this stipulation are measuring points for vacuum and measuring points for combustion air and exhaust gas.

Piping shall be of approved quality and sized for the particular service. In all cases the pipe size shall be chosen to ensure strength and freedom from blockage. Instrument impulse pipe work shall be manufactured from a suitable grade of stainless steel to the approval of the Engineer.

For gas measurements the pressure sensor shall be arranged above the tapping point; if this arrangement is impossible condensate craps and blow down valves shall be installed.

For liquid measurements the pressure sensor shall be arranged below the tapping point, gas traps and blow-off valves shall be mounted if this is impossible.

For steam pressure measurements the connecting tube between tapping point and pressure gauge or transmitter shall incorporate a condensing syphon.

The liquid columns in the connecting tubes shall be considered in the calibration of the pressure gauges and transmitters.

Open blow down/drain connections shall not be arranged within panels and local equipment. Instead it shall be led to a drain external to the panel.

All valves shall be installed so that they are accessible for maintenance from a floor or permanent structure landing.

Tapping points for pressure gauges or transmitters to be installed in heavy fuel oil systems are to be provided with seal pots or with separating dia-phragms.

In addition to the above requirements, special valve block equipment shall be provided, where differential pressure is. to be measured.

The blow-off valves must be separated from the valve block, if test connec-tions are required.

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0.6.18.6.5 Analyses measurements

0.6.18.6.5.1 Analyses of steam and water

Conductivity electrodes, pH-electrodes, and other sensors for analysis may only be built directly into pipes if the medium pressure is below 25 bar. In all other cases sampling devices shall be provided.

Sampling devices and analyzers for steam and water shall be centralized by groups on sampling racks. These devices shall simultaneously serve for local supervision and manual sample taking as well.

Furthermore, these sampling devices shall operate in a way that first cooling and then throttling of the medium takes place.

The sampling system shall include but not be limited to all' probes, valves, filters, coolers, drainage facilities, flow regulators, flow meters, piping and pumps as necessary, to give the analyzer a representative and suitably conditioned sample.

Each automatic analysis sampling point shall be provided with a manual sampling point to permit a sample to be easily taken. Manual sampling shall not interrupt automatic sampling. All sampling lines shall be run to common sampling racks on which shall be fitted all the analysis associated equipment.

For convenient manual sample taking the sampling devices shall be equipped with funnels with inherent screens to locate the sample bottles upon.

The sample racks shall be situated in such a way as to obtain minimum length of the tubes from the sample tapping points to the racks. These tubes shall be of nickel or equivalent material.

Whenever required for a useful analysis measurement, the installed sampling device shall include a cation exchanger. The cation filters shall have visible colour indicators to show when they have to be regenerated.

For all analyzers temperature compensation shall be provided, with the temperature sensor being an integral part of the probe.

Chlorine residual monitors and hypochlorite concentration meters shall preferably be able to measure high and low concentrations: Measurement of hypochlorite concentration shall not be affected by the presence of other oxidizing components in the sample.

Individual or multiple prefabricated analyser installations shall be used to reduce site installation work. This prefabrication shall include sample conditioners, analyzers, air and electrical distribution, cooling water distribution or coolant circulating system all piped and wired on a common frame. Interconnecting pipe work and accessories shall be of stainless steel. The arrangement shall permit testing of the entire assembly before dispatch to site and shall be arranged for convenient removal from on-line operation to facilitate routine maintenance and calibration.

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0.6.18.6.5.2 Analysis of exhaust gas

The analysis of 02, CO, NOx, SOx and dust in the exhaust gas shall be performed for each unit by appropriate analyzers of proven type.

The equipment shall be constructed for operation in dusty and humid environments at high ambient and exhaust gas temperatures. The use of equipment capable of multi-parameter measurement shall be considered.

The reliability and response time of the 02-analyzer shall be of the quality' required for closed-loop control. A zirconium oxide measuring cell shall be used. Maintenance shall not be more than once a week.

Analyzers provided shall. have auto-calibration for zero and span as well as self-diagnostic functions. The sampling probes shall preferably be vertically installed on the top of horizontal exhaust gas ducts, in order to avoid blockages.

In order to keep the sampling lays to acceptable limits the analyzers shall be located close to their sample take-off point, so that easy access to the sample take-off point and to the analyzers shall be provided for maintenance.

The exhaust gas sampling lines shall be heated to prevent condensation and shall not form a siphon in the case where condensate may be collected during heater failure. Condensate drainage facilities shall be provided the analyzers.

Generally, the analyzers and the sampling probe equipment shall be mounted in an air-conditioned room or container.

Monitoring and supervision of emission measurements (half-hour mean values, etc.) shall be done in the DCS.

Power failure and system failures of analyzers shall be monitored in the DCS by a group alarm.

Adequate measures shall be taken to eliminate dirt from the sampled gas before it reaches the analyzer. Besides; effective measures shall be taken to avoid-sulfuric corrosion within the samplers/or analyzers.� .

The analyzers shall be a type which does not continuously consume refer-ence gases (like hydrogen).

The analyzers shall fulfill the following requirements: maximum

long-time drift (zero): ± 2% of full scale deflection per week

long- time drift (sensitivity): ± 2% of the set point per week

influence of temperature ± 2% of full scale deflection per 100e

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indication time constant: 20 sec. per 90% of full deflection

linearity: ±3% of full scale deflection

0.6.18.6.6 Level measurements

The remote measurements for the liquid level in the boiler drums and banks with a steam cushion of pressure above atmosphere shall be of the hydro-static principle by means of a differential pressure transmitter.

For liquid measurements in condensers and tanks with a steam cushion of pressure below atmosphere level transmitters of displacement type or of differential pressure type with isolating membranes shall be used. The membranes shall be installed close to the condenser or tank.

Where detection of discrete levels is required, the simple float operated switch should be used, however each switch shall have snap action with limited hysteresis to prevent contact bounce caused by small fluctuations in level.

Switches used for level detection shall provide facilities for testing the mechanical and electrical operation of the switch without its removal from the process. Isolation by means or shut-off valve will be allowable during testing.

POI' measurement of large storage tanks, the load indication and transmitting mechanism shall be located at the base of the tank.

The transmitters shall be as specified under Chapter B0.6.18.6.1.

For special applications such as chemical tanks, techniques such as ultra-sonic, capacitance probes, etc. should be considered.

For measurements where a reference leg of process fluid is used. the design of the system shall ensure that the reference leg is fully maintained at its prescribed height during all conditions of process level change and changes in process conditions and the density of the reference leg docs not vary from that of the process fluid due to. temperature changes or other reasons.

All measurement transmitters for differential pressure shall be provided with:

a) shut-off valves to be arranged directly at the condensing vessels and active pressure tapping points

b) valve blocks enabling the transmitter to be isolated from the active pressure and enabling the transmitter zero point to be checked

c) separate blow-off valves for cleaning the active pressure tubes.

The aforementioned valves shall be of the weld-in type.

Where a standpipe exists, the level transmitters or level switches must be connected to the standpipe by means of shut-off valves, so that the units can be replaced easily in service.

Local level indicators of big tanks shall be equipped with a scale length of full height of the tank. Locally mounted water level indicators shall be of bicolor

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type equipped with electric illumination, working in such a way that the water level is clearly readable as a column over the complete measuring range.

Level indicators showing the level only as a point will not be accepted.

The indicating range of local level indicators shall cover all switching points of level switches mounted on the tank or similar as a minimum requirement.

On all forms of measurement all parts of the switch, transmitter, etc. in contact with the process fluid shall be made of material compatible with the process fluid, Stainless steel shall normally be used for all corrosive duties

0.6.18.6.7 Electrical measurements.

0.6.18.6.7.1 Electrical equipment, instrument and meters

All indicating instruments shall comply with IEC-51 and shall have a Class Index between 1.0 and 5.0 depending upon scale length. They shall be of approved type, make and size and flush mounted with square bezels and square or rectangular faces. The cases of instrument and meters shall be dust and moisture proof and suitable for use in a tropical climate.

Instrument scales shall be clearly divided and indelibly marked.

Where ammeters are provided for indication of motor currents they shall be supplied with overload scales indicating the six times full load current.

The dials of such ammeters shall include a red line to indicate the full load current of the motor.

Instrument pointers shall be of low parallax type and means shall be provided for zero adjustments without dismantling. They shall be as arranged that the normal working indication is between 50 and 75% of full-scale deflection.

All integrating meters shall be flush mounted and shall comply with the relevant parts of IEC-521 for MWh meters, with dial type registers. Approved test terminal blocks of the three-phase type shall be provided

for connecting in circuit with each meter a portable testing meter.

The meters shall be able to record min. 10000 hours and shall be suitable for unsymmetrically loaded phases.

For generator circuits all export only and import only MWh meters shall have maximum demand indicators of class 0.5. They shall be fitted with inductive transmitters to operate MWh electronic summators with maximum demand indicators. All maximum demand indicators shall have a 30 minutes resetting period.

All other meters for acceptance testing shall be not less than class 1.0.

All instruments and apparatus shall be capable of carrying continuously 120% of their full load current without undue heating. They shall not be damaged by the passage of fault currents within the rating of the associated switchgear through

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the primaries of their corresponding instrument transformers.

All voltage circuits to instruments shall be protected by a fuse in each unearthed phase of the circuit placed as close as practicable to the main connections. All power factor indicators shall have the star point of their current coils brought out to a separate terminal which shall be connected to the star point of the instrument current transformer secondary windings.

The scales of all direct current instruments and of all alternating current indicating watt meters shall be arranged so that the instruments will read 10% of the full scale reading below zero and this part of the scale shall be marked in red.

In duo-directional circuits centre zero instruments shall be used.

Watt meters and Var meters shall include the limits for inductive and capacitive power factor.

When more than one measured value will be indicated on the same instrument, the measuring point selector switch will be provided next to the instrument and will be engraved with a legend of the measuring points.

0.6.18.6.7.2 Transducers

General

Transducer for electrical power metering shall comply with IEC-688-1.

All transducers shall be provided with a nameplate, indelibly marked with the following information:

• name of manufacturer • manufacturer's type reference • serial number • rate input voltage and current, as appropriate • DC output current • overall ratio (e.g. Watts/mA).

The type of transducers selected shall be suitable for use in digital instru-mentation schemes and the outputs of all transducers shall have a linear relationship with the measured quantity. Transducers shall be self-powered, where possible, or powered from the RTU battery power supply.

Each current input shall be capable of carrying 200% rated current continuously and shall withstand 10 times rated current for 5 seconds without damage. The output shall be accurate up to 120% rated output. In addition, transducer inputs shall withstand 30 times rated input current on each range for 3 seconds without damage.

Transducers shall withstand for one hour, without damage, a short circuit on the output terminals when the input circuits arc carrying rated voltage and current.

The error in transducer output shall be not more than ± 0.5% of full rated output over as great a part of the output range as possible. For all inputs, the output error shall not exceed ± 0.2% due to ± 10% voltage variation in the

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voltage circuit input nor exceed ± 0.5% due to a ± 10% change in the input frequency.

The root-mean square ripple current shall not exceed 5% of the maximum signal current and shall preferably be much less.

The response time to reach and remain above 80% of the final steady value for a step change in input from zero to a value equal to full rated output shall not exceed 1 second.

Adjusters shall be provided to allow adjustment of the output current to be made to compensate for errors of primary circuit transformers. Adjustment may be continuous or in fixed steps. A range of ± 2% adjustment in the output current shall be provided.

Power transducers

For the measurement of three-phase balanced power flows; Watt/Var transducers designed for reversible real and reactive power flows, except where specified otherwise, shall be used which have DC current outputs proportional to the AC real and reactive inputs. The lineary shall be ± 0.25%.

The transducer output shall be 0 to 10 mA for single direction power flow, and -10 to 0 to + 10 mA for reversible flow, respectively~ representing 0 to 1.2 amps input current at nominal rated input voltage. The polarity of transducers for measurement of both forward and reverse power flow shall be such that power flow into the busbar is positive.

The burden imposed on the primary circuit current and voltage transformers at full rated input shall not exceed 2 VA and 12 VA respectively.

The additional burden imposed on the primary circuit current transformer at full rated input when the dc output is open circuited shall not exceed 2 VA, and the transducer's steady output voltage shall not exceed 25 volts.

Voltage transducers

Voltage transducers shall have a DC output current proportional to the AC input voltage. The rated input voltage shall be 110 volts AC and the transducer output shall be 0 to 10 mA representing 0% to 120% of rated input voltage.

The phase angle voltage transducer shall have an inverted linear output of 10 to 0 mA representing an input range of 0 to 240% of rated input voltage.

The burden imposed on the primary circuit voltage transformer at nominal input shall not exceed 5 VA.

Current transducers

Current transducers shall have a DC output current proportional to the AC input current. The transducer output shall be 0 to 10 mA representing 0 to 1.2 amps input current.

The nominal input current rating shall be 1 amp. The effective range of the

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transducer shall be 0 to 120% of the rated input current and the accuracy shall be ± 0.5% at full rated output.

The burden imposed on the primary circuit current transformer at nominal maximum input shall not exceed 2 VA.

Frequency transducers

Frequency transducers shall have a dc output current proportional to system frequency. The transducer shall record with an accuracy of ± 0.25% over the range 45.00 to 55.00 Hz. The nominal input voltage shall be 110 V and the output range of 10 mA.

Summators

Where specified or indicated on drawings, a summator shall be provided to summate the outputs of several transducers. The summa tor output sball be 0 to 10 mA for single direction flow, and -10 to 0 to + 10 mA for reversible flow. The error of the summator output shall be not more than ± 0.5% of full rated output over as great a part of the output range as possible.

Transformer tap changer position indicators

Transformer tap changer position transducer shall have a DC output of current proportional to the tap position.

The transducer shall have an output range of 0-10 mA representing tap position 1 to maximum tap position. Tap 1 should be at 1 mA and maximum tap at 9 mA. Due account shall be taken of tap change transfer taps positions which do not affect voltage output.

0.6.18.6.8 Position measurements

For the continuous remote position indication of valves, dampers etc. also transmitters with impressed output signal of 4-20 mA shall be employed. Therefore, electronic position transmitters shall be used.

Position transmitters of the potentiometer type will net be accepted.

Binary position switches shall be of the proximity type.

0.6.18.6.9 Contact devices

Where binary signals cannot be derived from an analog value. binary transmitters e.g. temperature switches, pressure switches etc. may be used. Indicators with integrated limit switches are allowed within package units. Preferably limit switches shall be of the proximity type.

All switches shall be of robust design and reliable performance. The switches shall have an adjustable switching hysteresis.

The set point and the dead band (reset point) of each switch shall be adjustable

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from inside the case, over the full range specified. The set point and reset point shall be indicated 011 the adjusting mechanism.

The switches shall be housed in robust, dust and moisture proof cases having glanded cable entries and shall be suitable for the ambient conditions local to the equipment, on which they are mounted.

Contacts of level switches, pressure switches, temperature switches, limit switches, and of all other pilots shall be of the snap-action type. The creeping action type will not be acceptable.

Contact devices for interlocking systems shall be separate, i.e. contact devices serving commonly for interlocking and other purposes will not he 'accepted.

0.6.18.6.10 Vibration measurements

Vibration shall be measured at large rotating or reciprocating machinery for protection and predictive maintenance. Suitable indications shall be provided in the Central Control Room for each measurement point and the measurement shall be suitably alarmed where high vibration levels may cause possible damage or affect the safety of the power plant.

The vibration monitoring system shall be reliable, accurate, easy to maintain, and suitable for use in such ambient conditions appertaining to the intended plant installation.

Where feasible, standardization and interchangeability of components shall be implemented.

The following criteria shall be used as a guideline for rotating machinery, in order to ascertain the monitoring points, principles of what signal shall be measured, what is displayed, and what mechanical conditions entail alarm and/or trip status:

• Non-contacting proximity probes shall be provided unless otherwise specified for measuring rotor shaft vibration and axial position,

• Vibration measurements shall be in displacement microns peak to peak,

• In cases which, because of process conditions, accessibility or noncritical service, may entail the use of machine casing mounted vibration transmitters, the transmitters shall be of the "acceleration" type incorporating a filter network, if necessary along with integration in the monitor unit for vibration read-out in velocity mm/sec RMS. For alarm only, one transducer may be used. For alarm and trip conditions 3 transmitters shall be used with a voting system (Le. one high reading out of three = alarm, two out of three = trip). Contacting type of equipment shall meet the requirements of ISO 2954,

• Velocity type transmitters shall be used as an alternative to accelerometers when machine rotational speed and generated vibration frequency conditions dictate,

• Individual read-out of all channels shall be provided. Display shall be by means of a multi-point indicator and digital selector,

• Facilities for trend monitoring, using DCS integrated features, shall be provided on the turbo-generator bearings as an aid for predictive mainte-nance purposes,

• Buffered signals at the monitor shall be a requirement to enable external data acquisition, if such is necessary,

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• Facilities shall be provided for the calibration of the instrumentation system.

0.6.18.6.11 Control valves

0.6.18.6.11.1 General

General requirements for control valves are contained in Clause B06 and further details are given below.

0.6.18.6.11.2 Valve sizing

Control valves shall be standardized wherever possible and shall be sized for optimum control. The sizing calculations shall include CV, noise and cavitation calculations.

Valves bodies shall in all cases match the piping pressure and temperature rating specifications as a minimum and the operating point on the valve characteristic, i.e. lift/throughput curve should be within the 60-70% operating range.

0.6.18.6.11.3 Valve bodies

For normal service duties valve bodies shall be of carbon steel with and connections flanged raised face, unless process conditions dictate or otherwise specified. Flange type connections shall in all cases match the piping specifications as a minimum but never Iess than a pressure rating equivalent to ANSI Class 300 specification. (See ANSI B36. 10 for full details rating schedules.)

For liquid services with high pressure drop cage-guided control valves shall be provided having the plug supported at the critical area.

For severely erosive service the fluid impact area inside the valve body shall be covered by welded stellite.

For high pressure superheated steam service the complete valve body shall be of Cr 13 Mo 44 or equivalent.

0.6.18.6.11.4 Plug characteristics

A linear characteristic shall be provided when the pressure drop across the control valve under all operating conditions is more than 2/3 of the pressure drop across the valve in the closed position. Unless otherwise approved an equal percentage characteristic shall he provided for all other cases.

0.6.18.6.11.5 Trim material and stem packing

Control valve trims shall be of stainless steel ANSI 316 or equivalent ns n minimum where appropriate according to the service, fluid and conditions.

Hardened and/or stellite plug and seal rings shall be used for the following applications:

• erosive service

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• wet steam service with pressure drop above 5 bar • general service with pressure drops greater than 5 bar.

For the above applications valves up to and including 38 mm shall have their plug and scat rings made from solid stellite. For larger sizes, Ihc plug and scat rings shall be made from stainless steel, ANSI 316 and be completely metal coated wilh Stellite No.6

Valves shall be provided with teflon asbestos packing and a lubricator assembly. For services with fluid temperatures above 200°C or below 10°C a normalizing bonnet shall be provided to keep the packing box at ambient temperature

Bellow seals shall be used on valve stem packing for services with dangerous/poisonous fluids: Suitable valve stem material shall be provided with valves used on chlorine services or other services which become acidic when in contact with a moist atmosphere.

0.6.18.6.11.6 Valve types

For normal duty services globe type valves shall be used.

Where very large sizes are involved (on high flows), butterfly type valves shall be used and it will be “balanced torque" type disc usable to the fully open position. The overall shaft rating shall be at least 25% above rated pressure as differential across the closed valve.

Multi-stage valves shall be used on services, e.g. steam and gas, having very high pressure drops which would result in supersonic velocity inside a conventional body and shock waves in the piping creating unacceptable noise levels.

For liquids the exit trim velocity shall not exceed 30m/sec.

For flashing service the exit trim velocity shall not exceed 22.5 m/sec.

For gas and steam the velocity head in line shall be less than 70 psia.

Supplier shall provide calculations demonstrating meeting the above velocity requirements.

The maximum allowable noise level shall be 85 dB A or less.

Angle valves shall be provided:

• for steam pressure reducing desuperheating stations of the "combination" type

• for erosive service, e.g. slurries • on applications where solid contaminants might settle in the valve body • on hydrocarbon services with tendency for choking.

Ball valves shall be used for on-off and throttling services under moderate operating conditions.

Where alternative specifications are considered more appropriate then

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details and justification shall be submitted to the Engineer for approval.

0.6.18.6.11.7 Installation

The installation shall include for upstream and downstream isolating valves and, and for critical control valves, a bypass valve for each control valve on all services. Unless otherwise agreed by the Engineer the bypass valve providing tight shut-off shall have the same characteristics and construction as the control main valve. Any exceptions or variations to this requirement shall be subject to the approval of the Engineer. Where a service is subject to pressure above three bar g a 25 mm vent valve shall be provided, between the upstream and downstream isolating valves, in order to relieve the pressure to enable maintenance to be carried out on the control valve. Control valves shall be adequately supported in all cases and shall be accessible for maintenance. Local pressure gauges shall be provided at the upstream and downstream of each control valve.

0.6.18.6.12 Actuators

0.6.18.6.12.1 General

Unless otherwise specified actuators for modulating valves and dampers shall either be pneumatic or electrically operated. Self contained scaled hydraulic units may be considered where high thrusts or high speeds of operation are required but each application shall be to the approval of the Engineer.

Actuators for ON/OFF duty or manually positioned units shall generally be electrical motor driven, however the use of solenoid types on small valves shall be allowed dependent on duty.

The various types and sizes of actuators shall be rationalized and as far as possible each type shall be from a common manufacturer to facilitate interchangeability and spares.

The operation of all actuators, control valves and driven units, shall be so arranged as to ensure the safety of the "plant" under failure of control or actuating supplies.

Unless specified otherwise, the failure of a control signal or actuator power supply shall either:

a) cause the actuator to move to a safe position b) freeze in its last operating position.

With either action the failure mode shall be suitably monitored and the plant operator informed by some form of alarm.

Where pneumatic actuators arc used, an internal bias spring shall be used to obtain motive power 10 reach the safe position in the event supply failure

Where the type of actuator offered does not have the appropriate fail-safe facilities described above then the valve/damper shall have a second valve/damper in series or parallel as appropriate, designed to provide the correct

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failure response.

When an actuator is locked or moves to a safe position on failure detection, it shall not be allowed to return to automatic control without resetting action by the operator after restoration of the supply/control signal.

The failure response of all actuators in .the event of the loss of the prime mover (air pressure, oil pressure, electrical power) shall be indicated on the Piping and Instrumentation (P&I) diagrams, valve Sc11cdules, etc.

All modulating and regulating actuators shall be filled with position measurement for CCR indication of actuator position. This requirement applied irrespective of the operating mechanism, whether electric, pneumatic or hydraulic.

All actuators which are controlled remotely from a panel or from the CCR shall have independent control units and independent remote/local, auto/man functions where specified or applicable. It is not permitted to gang several actuators onto one signal output and independent positioning control shall be provided for each actuator.

Where control requirements call for split range operation, the computing of the split range shall be carried out externally from the actuator such that standard signal inputs to the actuator are maintained.

All actuators shall include a mechanical device to show the true position of the operating mechanism.

All actuators shall have a hand wheel for direct manual operation. The diameter of the hand whelp and geared effort shall be such that they are reasonably operable by one man. A lockable mechanical clutch mechanism shall be provided to inhibit power control of the actuators when the hand wheel is operated. The disengagement for hand control shall signal remotely to indicate that the normal operation of the actuator is inhibited.

All actuators shall be provided with a local control facility. which in general will be used for test purposes only. Such controls may take the following forms, as appropriate or specified:

a) Control initiations (i.e. raise, lower, etc.) with lockable local/remote selection when appropriate either on the actuator, in the direct vicinity of the actuator or on its associated switchgear.

b) A portable test facility for injecting the appropriate position demand signal either at the actuator or drive unit (switchgear or power amplifier).

0.6.18.6.12.2 Electrical actuation

Two classes of actuators are identified; firstly the motorized actuator which shall cover the isolating actuator type and including actuator type required: for open loop (binary) control; secondly the modulating actuator which shall cover the switched types and continuous control type required for closed loop control.

(a) Electrical actuators for isolating and binary control

Isolating actuators shall have short time ratings appropriate to duty cycle type S2

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10 min. to IEC 34-1, and n maintenance free interval better than 10,000 open/close cycles.

Unless otherwise specified actuators with integral or separate switch units may be offered. The contactors may be of the mechanical or static (thyristor) switch type. If a static switch is offered then the switclll1nit and actuator shall be supplied by the same manufacturer as a complete system.

The following features shall be provided for each actuator:

• DC open and close (raise and lower) command interposing relays • open and close travel limit switches (each with change over contacts) • torque switches in both directions (each with change over contacts) • open and close indicating lamps • open and close push buttons • instantaneous voltage phase sequence/failure monitoring relay • padlockable local/remote control selector switch • analogue actuator position signal shall only be supplied when specified • thermal overload protection.

The DC interposing relays (above) shall be energized by the control and instrumentation system power supplies and shall therefore be rated to be compliant with the standard binary signal levels (48 V, ± 24 V or 24 V).

All switch units and actuators shall be incorporated in enclosures with n protection class of at least IP 54. Better type enclosures shall be provided where specified for special applications. Contractors if not integral with the actuator shall be incorporated in the actuator boards, in in9ividual compart-ments logically arranged according to their function. These cubicles shall be accommodated in a switchgear room.

(b) Electrical actuators for modulating duties

Modulating and regulating (inching) actuators shall have a rating appropriate to duty cycle type S4 20% 1200 cycles/h to IEC 34-1 and a maintenance free interval better than 50,000 hours in normal operation.

These actuators shall be provided for closed loop control functions. Two principal types are recognized:

• Switched actuators

Each actuator shall be driven by a duration modulated switched power signal at the full AC supply voltage. Each shall feature either electro-magnetic or mechanical braking. However, the latter will only be accepted on low power single phase actuators and a brake life in excess of 107 operations shall be guaranteed by the Contractor. They shall not be used when full travel times of less than 20 seconds are required.

• Continuous control actuators

For each actuator the drive voltage and current or frequency of the AC power source shall be continuously varied to regulate the rate of operation. Each shall be capable of slow creep operations as well as rapid stroke action and the operating torque shall be sensibly

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independent of the speed of operation.

The continuous control actuator should be provided for all demanding modulating control applications in which high torque, a wide range of stroke rate and frequent correction is anticipated.

Unless otherwise specified actuators with integral or separate switch units may be offered. Static power amplifier/switch units (thyristor units) shall be provided for either type of modulating actuator.

If integrated within the actuator, the actuator and associated power amplifier unit shall be manufactured as a composite system with a minimum of three years of proven service reliability. In any case, the actuator and drive limit shall be rated continuously for the stalled condition and three phase motors. shall be provided for all actuators with ratings above 250 \watts.

The following features shall be provided for each actuator:

(i) the drive unit shall accept an analogue (4 - 20 mA) actuator position demand signal or pulsed raise and lower signals if an external position loop is provided

(ii) analogue actuator feedback position signal

(iii) a test facility

(iv) an override facility for stroking the actuator in either direction for binary control interventions

(v) monitoring of common fault conditions such as thyristor drive fault, motor temperature high, AC power supply failure, circuit continuity fault, high torque etc.

(vi) all necessary protection devices to protect the actuator and drive unit against abnormal operating conditions.

Generally the actuator drive units shall either be integrated in the actuator or be grouped and mounted within cubicles of appropriate enclosure standard. Unless otherwise specified the later cubicles shall be located in an electrical switchgear room to obtain protection from the normal plant environment.

The Engineer's approval shall be required where different types of actuators are offered to those specified above or where the drive unit and actuator are selected from different range of manufacture (preferably from two different manufacturers). Additionally these shall he subject to a type test, approved by the Engineer, to prove their satisfactory performance under equivalent operation conditions.

0.6.18.6.12.3 Pneumatic actuators

All pneumatic actuators shall be provided with a positioner using a standard 0.2 to 1.0 bar signal.

Pneumatic actuators and drive units shall automatically return to the rest position upon signal and/or air supply failure unless "process control" or the specification requirements dictate for "stay put" response.

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Where "lock up" devices are provided on those services requiring the actuator to remain in the position prevailing immediately before an operating medium failure, the following two methods of "freezing" are acceptable:

a) The pneumatic system may be locked, but equipment used for this purpose shall always be installed between a positioner output and an actuator input.

b) The final regulator may be locked by mechanical means upon receipt of a falling supply prcsslI1"e signal.

All pneumatic control equipment, control drives rind control valves, shall be capable of satisfactory operating on n main air supply pressure of approximately 7 bar g normal down to 5.5 bar g minimum.

On positioners where the output control air is of equal range to that of the input signal air (e.g. 0.2 to 1.0 bar) they shall be furnished with integral pneumatic "bypass switch" facilities for applying signal air direct to the actuator.

All positioners and electro pneumatic: converters shall be furnished with three pressure gauges: air supply, signal input and control air output and an air filter regulator set. All pneumatic tubing to drives and actuators shall, unless otherwise agreed to by the Engineer, be in copper which shall be sheathed in PVC.

Where an electro pneumatic converter precedes or is integral with the positioner then facilities are to be provided for the connections of portable test equipment for the injection of electrical reference signals or pulses to allow the stroking of the actuator for test purposes.

All on/off (open/close) actuation systems shall be provided with suitable tamper proof adjustments for actuator stroking time, independent for the open and close stroke.

All actuators which are in control loops shall be provided with robust precision position measuring transmitters for CCR indication.

Solenoid valves for controlling the air to/from actuators shall be mounted on n rigid mounting frame or plate independent from the actuator. It is not permitted to mount the solenoid valve on' the actuator, unless agreed by the Engineer. Solenoid valves shall not be merely supported from the air piping connections.

0.6.18.6.12.4 Solenoid valves

In lines with nominal diameters of up to DN 25, as well as for piloting pneumatic actuators, suitable solenoid valves shall be used. Valves with power ratings up to 30 \V shall be controlled directly at 24 V DC from the I&C system. For powers over 30 W, solenoid valves for a 120 or 230 V AC shall be employed. Solenoid valves shall be fused individually. Electrical connections are made by means of plug connectors with the mating connector forming part of the scope of supplies

0.6.18.6.12.5 Electro hydraulic actuators

Generally these actuators shall only be used where high thrusts are required combined with fast operating times and the applications requirements cannot be met by the standard range of actuators used on the remainder of the contract.

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The units offered shall be or the self contained, fully sealed types which allow removal of the complete unit to n clean room for any maintenance requirements.

Units accepting either 4 - 20 mA signals or pulsed input signals shall be acceptable.

Failure of the internal hydraulic supply shall result in the actuator locking in its last operating position or stroking to its fail safe position and a suitable alarm being given to the operator.

0.6.18.6.13 Local instrumentation

All local instruments, necessary for local operation, maintenance and local supervision have to be delivered.

The scope of supply shall comprise but shall not be limited to:

• pressure indicator on the suction and discharge side of each pump and compressor

• pressure indicator at each heat exchanger inlet and outlet (except for sample coolers)

• temperature indicator at each heat exchanger inlet and outlet • pressure indicator upstream of each safety valve • temperature indicator at each bearing oil drain • pressure gauge at each tank or vessel if pressurized • differential pressure gauge at each important strainer or filler. • level indicator for each tank or basin • pressure gauge upstream and downstream of control valves . • pressure gauges at pneumatic actuators for air supply, signal input and control

air output.

All local instruments shall be as far as practicable be mounted free of vibration to allow a good readability. Wherever required damping elements are to be used. Local pressure and temperature gauge shall be installed on gauge boards either grouped or individually depending upon site conditions.

All local indicating instruments and test connections shall be included in the respective plant equipment as integrated parts. The scope of local indicating instruments and best connections shall enable the local operator to properly survey the equipment, and shall also allow to properly carry out all acceptance and other tests. All Local instruments of main equipment (pumps, motors, transformers) shall be readable from one side only, accessible for operation and maintenance.

0.6.18.7 Racks, junction boxes

Instrument racks

Wherever possible, instruments and devices, e.g. transmitters, thermo element cold junctions, terminal boxes, located in the field, shall be mounted on local instrument racks. The instrument racks shall be installed with due regard to control engineering needs, material-saving assembly and easy accessibility for maintenance and checking work, and shall be constructed of standard angle section steel.

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Junction boxes

In order to simplify local collection of cables and distribution of signals and to centralize connections in the plant the junction boxes shall be filled on nil the necessary

• cable crossover terminal points • electrical actuators • central collecting points for individual analog and binary signals and local

transmitters • central distribution points for local signals.

The necessary intermediate terminal boxes must at least have degree of protection IP 55 in accordance with IEC-529 and must be equipped with the necessary terminal strips and attachment components for the connection of the cables. The necessary earthing terminals shall be provided for the earthing of the boxes. In hazardous areas, terminal boxes shall be in accordance with EN 50019 or 50020, depending on zone classification.

0.6.18.8 Transmitter racks and piping

Wherever practicable, transmitter for flow, pressure etc., shall be installed readily accessible in the vicinity of the measuring point, free from vibration and protected against damage, moisture, fine dust, corrosive air, great temperature changes, sun radiation and rainfalls.

The transmitters shall be grouped and assembled as far as practicable on local transmitter racks or in cubicles (in open area).

The connecting lines between the primary elements and the transmitters shall be installed with an inclination in such a way that no air pockets (e.g. in case of liquid measurements) or no water locks can occur.

0.6.18.9 Programmable logic controller

Programmable logic controllers (PLC) shall be deployed in subsidiary installations and systems of higher complexity and shall provide a more open access for operation. Standard products of PLC manufacturers shall be used for which software developed by the process suppliers and proven for the specialized process is available.

The diversity of makes and types shall be kept to a minimum. The Employer/Engineer reserves the right to stipulate make and type following award of contract.

For signal exchange with the main DCS, PLCs shall be compatible with this system. Depending on the amount of information to be exchanged, parallel or serial interfacing shall be considered.

If only few signals are to be exchanged, parallel interfacing is preferred. Binary signals shall be exchanged via volt free signals. Analogue signals (4 - 20 mA) must be suitably decoupled.

If serial interfacing is used, the interface equipment between the PLC and the

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DCS must be capable of communication using an industrial standard protocol. The transmission baud rate shall be selected dependent on the application (e.g. 19200 baud or higher). If commands are issued from the DCS to the PLC, the time between command and PLC signal output shall not be more than 5 seconds. The same requirement goes for answer back signals from the PLC and updating of displays of analogue values coming from the PLC on the DCS monitor displays.

As a. minimum requirement, the offered serial link shall have a data integrity checking and retransmission facility in case of error detection, independent of the DCS or external system software. Hardware and software failures during data transmission shall be monitored and alarmed.

The communication link shall be redundant (two cables) but only one traffic controller shall be provided. In case of failure in the communication, quick manual switch-over to the standby communication link shall be possible.

The functions realized in the PLC and the method by which they are invoked shall be represented graphically similar to IEC-1131-3. Additionally, a description of the program shall be supplied.

Programming devices with keyboard, VDU and printer for ease of programming, effective on-line monitoring and diagnostic functions, together with the necessary equipment to write in and to erase EPROMs shall be provided.

The PLCs should be selected from minimum no. manufacturers (preferably two).

0.6.18.10 Control cubicles

PLC hardware and other associated control equipment shall be installed in suitable control cubicles. Where ambient conditions are suitable, these cubicles shall be set up in a protected area, near to the secondary system to be controlled. Should this not be possible, the cubicles shall be set up in local switchgear rooms or in local control rooms. The protection class shall be IP 54 as stipulated in IEC-529.

The required control elements and displays (annunciation anti status lights, analogue displays, switches etc.) shall be so configured that as far as possible they can be viewed from the associated secondary system. Should it be necessary to place the control and monitoring elements in the field, these shall be installed in separate, robust housings (protection c1nss IP 65).

In preference LED displays shall be used. Ease of access and operation of the equipment shall be ensured.

Where appropriate, visual display unit (VDUs) shall be employed for field operation and monitoring.

All cubicles shall be adequately ventilated in order that the heat generated by the equipment mounted there shall remain within the specified limits, even in the case of high ambient temperatures that may occur in the event of failure of the air-conditioning system.

Locally installed cubicles shall be suitable for the location in which they are situated and shall provide adequate protection against dust, moisture or mechanical damage for the equipment mounted therein. Sunshades shall be provided for all cubicle located outdoors.

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Table of Contents

0 xxx 0.0 xxx 0.1 xxx 0.2 xxx 0.3 xxx 0.4 xxx 0.5 xxx 0.6 xxx 0.7 Inspection and Testing 0.7.1 General 0.7.1.1 Workshop manufacturing and pre-assembly 0.7.1.2 Works inspections 0.7.2 Testing during manufacturing 0.7.2.1 Material tests 0.7.2.2 Tests at site 0.7.2.2.1 General remarks 0.7.2.2.2 Hydraulic tests 0.7.2.2.3 Test runs and functional tests

0.7.2.2.4 Visual inspection, checking of dimensions, test instruments

0.7.2.3 Manufacturing tests 0.7.2.3.1 Welding 0.7.2.3.2 Pressure testing

0.7.2.3.3 Testing of corrosion protection

0.7.2.4 Mechanical equipment 0.7.2.5 Electrical equipment 0.7.2.6 Control and monitoring equipment 0.7.3 Testing at site during installation 0.7.3.1 Erection Tests 0.7.3.2 Pre-commissioning tests 0.7.3.3 Tests on completion 0.7.4 Reliability Test run

0.7.5 Performance tests

0.8 Abbreviations

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0.7 Inspection and Testing 0.7.1 General

This section contains general requirements for inspection of material, parts, equipment and workmanship of the Plant during manufacture, assembling and erection and upon completion to demonstrate compliance with specification, codes and standards and to ensure overall reliability of plant operation and performance.

Development and implementation of test procedures for the construction inspection, start-up and performance testing and capacity demonstration of the Power Units and of the Plant shall be the responsibility of the Contractor. These test procedures are completely subject to Owner/Owner's Representative's approval.

The Contractor shall be responsible for providing all supplies required for carrying out such tests, except to the fuel used during Reliability Test Run and Performance Tests.

The overall testing program for the Project shall consist of the following:

• shop inspections and testing, • construction inspections, and testing, • mechanical completion, erection checks • pre-commissioning and commissioning tests • tests on completion • Reliability Test Run (6 weeks) and Performance Tests.

The Owner/Owner's Representative shall have the right to have their representatives present during inspections and tests of major Plant equipment and systems in the workshops and during construction. The presence of the Owner/Owner's Representative during any inspection or test shall in no way relieve the Contractor of its responsibility for supplying the equipment or systems in accordance with the milestone dates.

The Owner/Owner's Representative will be notified by the Contractor in writing at least twenty (20) days prior to such testing and inspection:

Three (3) months after effective date of Contract, the Contractor shall submit to the Owner/Owner's Representative all relevant test documents, which shall include:

• test program • test standards • type of inspection and tests • tests which are to be witnessed by third parties • quality control procedure.

Six (6) months prior to the proposed start of commissioning the Contractor shall submit to the Owner/Owner's Representative:

• commissioning test program • commissioning procedures • tests on completion.

Six (6) months prior to commissioning the Contractor shall submit to the

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Owner/Owner's Representative for the performance tests:

• test program • test standards • manpower and deployment schedule of' the Contractor for performing the tests

forms of test records and report . • description of instrumentation to be used, including accuracy, and calibration

test results • method of data recording • method and equations/correction curves used for adjustment of recorded data to

the design conditions.

The results of all tests shall be certified by the manufacturer, Contractor or independent agency as appropriate.

Document files containing material certificates, welding procedures, test report etc. shall be compiled for each item of plant and shall be suitably identified (including equipment classification reference) and bound.

0.7.1.1 Workshop manufacturing and pre-assembly

All workshop fabricated components and parts of the plant shall, to the fullest practical extent, be formed, machined, fitted, welded, stress-relieved. X-rayed, adjusted, tested, cleaned and painted. The equipment shall be preassembled in the workshop of the Contractor or his sub-contractors to the maximum possible extent, then dismantled only as far as required for safe and proper shipment, in order to keep erection work on site to a minimum. Equipment and parts shall be marked, labeled or otherwise identified to facilitate assembly and erection on site. Marks and labels shall be fixed in such a manner so that deformation or obliteration shall not occur during shipment, storage and erection on site.

The equipment shall be designed and fabricated in accordance with the industrial standards to reach the highest possible grade of reliability and a minimal and easy maintenance.

Special attention shall be paid to standardisation and interchangeability of plant components.

0.7.1.2 Works' inspections

The equipment to be supplied under this Contract shall be subject to works' inspections and workshop tests.

• The Contractor shall, after consulting the Owner/Owner's Representative, give the Owner/Owner's Representative thirty (30) days notice in writing of the date on and the place at which any plant will be ready for testing as provided in the Contract and unless the Owner/Owner's Representative shall attend the place so named on the date which the Contractor has stated in his notice, the Contractor may proceed with the tests, which shall deemed to have been made in the Owner/Owner's Representative's presence and shall forthwith forward to the Owner/Owner's Representative duly certified copies of the test readings .

• Where the Contractor provides for test in the factory of the Contractor except where otherwise specified shall provide free of charge such assistance, labour, materials, electricity, fuel, stores, apparatus, machines and instruments as may be required and as may be reasonably demanded and approved by the

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Owner/Owner's Representative to carry out such tests efficiently.

As stipulated in this section, the Contractor shall issue a quality assurance programme, indicating the kind and extent of inspections and tests to be carried out on plant components. These inspections and tests shalI prove whether the equipment fulfils the requirements of the Contract in view of

• safety conditions • consideration of the applied standards and regulations • execution of workmanship • conformity with the present state of modern technology.

The following procedure has to be adhered to with respect to test certificates:

Whenever inspections or tests are carried out in the manufacturers' workshop, all material certificates as well as all other intermediate test certificates, in accordance with the agreed upon test schedule, shall be made available to the Owner/Owner/Owner's Representative for inspection. Besides the latest issue of the related drawings, indicating also the state of approval by the Owner/Owner's Representative, shall be made available.

The same applies to the final works' inspections or workshop tests when all test certificates have to be submitted to the Owner/Owner's Representative.

Further, for each kind of test, a "Test and Inspection Manual" has to be prepared showing all steps of the test procedure as well as the relating standards and codes.

All these test manuals have to be sent to the Owner/Owner's Representative.

0.7.2 Testing during manufacturing

0.7.2.1 Material tests

Test specimens shall be taken from all important forgings, castings, tubing, etc., in accordance with the relevant standards and codes. Dimensions shall be adequate for the purpose intended and the test specimen shall accompany the component through all phases of the heat treatment. Before cutting or otherwise removing the test specimens, these shall be permanently banded together with the forgings, castings or components which they represent and, if requested, in the presence of the Owner/Owner's Representative. Except where expressively otherwise approved, all test specimens shall be machined to the dimensions specified in the relevant standards find codes. Steel castings and forgings, in all cases, be annealed before the test specimens are withdrawn.

Chemical analysis and mechanical properties of the material concerned shall also be submitted.

All casting components shall be tested for compliance with the relevant standards and codes and shall be suitable for the purpose for which the castings are to be used. The chemical analysis and mechanical properties of the material tested shall be provided by the Contractor. The results obtained from these material tests shall be in compliance with the values contained in the relevant standards and codes and with the figures quoted in the relevant sections of the Contract, if any X-ray examination and ultrasonic examination of circumferential, longitudinal, nozzle

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welded joints, stiffening rings, etc., shall be carried out by the Contractor in compliance with the standards under which the relevant equipment will be designed.

All castings and forging shall be subjected to X-ray and/or ultrasonic tests before the start of machining procedures, in order to detect defects as early as possible and to replace in time defective parts, thus avoiding undue delay in the manufacture and delivery of plant components. After partial machining in the Contractor's workshop, further tests may be performed. No repair welding machining of castings and forgings of major components shall be carried out without prior inspection and confirmation by the Owner/Owner's Representative. In case of a rejection, written and certified notice must be given to the Owner/Owner's Representative, indicating also measures undertaken by the Contractor in order to cope with the requirements 'of the Contract.

Major steel forgings

Purchase specifications shall clearly state the quality and inspection requirements and should include, but not be limited to:

a) chemical composition range b) heat treatment c) mechanical test specimen locations d) mechanical properties e) magnetic properties (when applicable) f) non-destructive testing

- methods and procedures - stage and extent of application - recordable indication size - allowable indication size

g) thermal stability test (HP and reheat turbine shafts only)

Each forging shall be suitably marked with an identification number which shall transferred throughout all machining stages. The identification number shall be indicated on all documents relating to the forging.

Repair welding will not be permitted on rotating parts and on other components the proposal will be subject to approval by the Owner/Owner's Representative.

Rotor forgings

The profile of forgings at the stage of final ultrasonic Inspection should be such as to minimize the regions where complete coverage is not possible.

Ultrasonic indications should be measured by the equivalent flat bottomed hole or AVG (DGS) method.

The toughness of rim and core (where applicable) material shall be evaluated by testing charpy V impact specimens over a range of temperatures and thus determining the 50% fibrosity fracture appearance temperature.

Allowable indication size and material toughness are interdependent design related criteria and the Contractor must be prepared, if requested by the Owner/Owner's Representative's Representative, to justify his proposals by reference to fracture

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mechanics calculations.

Bores, when provided, shall be magnetic particle inspected and a suitable intrascope used for examination.

Major steel castings

Purchase specifications shall clearly state the quality and inspection requirements and should include:

a) chemical composition range b) heat treatment c) mechanical test specimen locations d) mechanical properties e) non-destructive testing

- methods and procedures - stage and extent of application - recordable indication size - allowable indication size

f) other tests g) standard weld repair procedure.

Each casting shall be identified by hand stamped or cast-on reference numbers which shall be Indicated on all documents relating to the casting.

Non-destructive testing

Minimum requirements are as follows:

a) Crack detection of critical areas of castings which in the case of castings to operate at high temperature or high pressure shall consist of 100% 'of all accessible areas. Magnetic particle inspection shall be used for ferritic steel castings.

b) Ultrasonic inspection of all surfaces of castings to operate at high temperature or high pressure.

c) Ultrasonic thickness check of critical areas.

d) Radiographic examination adjacent to future butt weld regions (Acceptance Standard Level of ASTM E446 or E186 as appropriate):

e) Radiographic examination shall also be used to assist in defining defects indicated by ultrasonic inspection.

In addition to being applied as necessary quality control on as cast items, inspections outlined in a) and b) above shall be applied to the finally heat treated casting.

Prior to non-destructive testing all surfaces shall be satisfactorily prepared and visually examined.

Repair welding

Unacceptable defects observed by visual examination or indicated by non-destructive testing shall be excavated by chipping or thermal gauging and grinding

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and their complete removal proved by crack detection.

In the case of excavations which penetrate more than 25 mm or 50% of the wall thickness or cover more than 10,000 mm2 area the Owner/Owner's Representative's Representative written approval of the proposed repair must be obtained.

Only welders qualified by performance tests on similar cast materials shall be used.

On completion of repair welded areas shall be ground smooth and carefully blended into the surrounding material. The repaired areas shall be surface crack detected, magnetic particle inspection being used for erratic steel castings and in addition ultrasonic inspection shall be used on castings to operate at high temperature or high pressure.

Steel plates and sections

The following requirements, which may be supplementary to the applicable material standards, shall be considered when selecting material grades:

• impact testing of plate or sections over 50 mm thick (impact requirements to be dependent on application)

• ultrasonic testing of plate where the presence of non-metallic may interfere with the interpretation of ultrasonic testing of future welds

• ultrasonic testing and through thickness ductility measurement, where the application involves the risk of lamellar tearing in the material at regions of high restraint (e. g. at set-on nozzle locations or cruciform joints)

• ultrasonic testing clad materials to detect lack of bonding (proposed rectification procedures shall be submitted for the approval of the Owner/Owner's Representative.

Reinforced thermosetting resin pipes (if in scope of supply)

Checks shall be made on all raw materials to ensure that they comply with the relevant ASTM Standard.

All deliveries of resin shall be checked for consistency by viscosity and reactivity. Any resins deviating from the manufacturer's published figures shall not be used.

Testing of reinforced thermosetting resin pipes:

• Long term hoop strength (type test for pressure pipes only)

In accordance with ASTM D2992 Procedure D with the exception that the test results shall be extrapolated to determine the stress which the pipe can withstand for a period of 60 years without failure. The lower 95% confidence limit at 60 years shall also be calculated.

• Hydraulic test

100% of the pipes shall be subjected to an internal hydraulic pressure test at the manufacturer's works prior to delivery. The test shall be applied to a pressure equal to 1.5 times the maximum working pressure stated for each classification of pipe. The test pressure shall be applied for a minimum period of 5 minutes

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without signs of leakage.

In addition to the above the first pipe and every thirtieth thereafter of each class and diameter shall be maintained at test pressure for a minimum of 4 hours without signs of leakage.

Each pipe and fitting shall be subjected to an internal low pressure air test at the manufacturer's works prior to delivery. The test pressure shall be an overpressure of 0.1 bar and this shall be applied for a minimum period of 5 minutes without signs of leakage or distress. Fittings which are of mitred construction shall be manufactured from pipes which have successfully passed the tests defined above.

• Dimensions

The dimensions and tolerances of all pipes shall be determined in accordance with ASTM-D 2122

• Stiffness

A minimum of one pipe for every 30 pipes manufactured shall be tested for stiffness in accordance with ASTM-D 2412 "Method of Test for External Loading Properties of Plastic Pipe� by Parallel Plate Loading". A minimum of one pipe of each class and diameter of pipe shall be tested.

• Longitudinal and hoop tensile strength

The tensile strength properties of a minimum of one pipe for every 100 pipes manufactured shall be measured in accordance with ASTM-D 638. A minimum of one pipe of each class and diameter of pipe shall be tested

• Cure

Curing, to be tested by the Barcol Hardness test determined in accordance with ASTM-D 2583 standard: 100 % of the produced pieces. Minimum acceptable hardness is 90% of the value recommended by the resin manufacturer of the particular resin used, when non-reinforced. The sample pipe shall also withstand a commercial acetone test on the internal portion of the laminate.

• Loss on ignition

A minimum of one pipe for every 30 pipes manufactured shall be tested in accordance with ASTM-D 2584 "Standard Method of Test for Ignition Loss of Cured Reinforced Resins".

• Joint tests

A minimum of two pipes in every] 00 pipes manufactured shall be jointed and tested in accordance with the requirements of section 7.2 of ASTM-D 3262.

• Visual inspection

Each pipe and fitting shall be subjected to a complete visual inspection before shipment in accordance with ASTM-D 2563.

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• Vacuum test

Vacuum test of pipe shall be carried out for each diameter once at beginning of production. The vacuum to be applied shall be equivalent to the condition which occurs during full vacuum. The corresponding derated vacuum for this test shall be proved by the pipe manufacturer.

• Failure of tests on completed pipes

In the event of a specimen not fulfilling the minimum requirements for strain corrosion resistance, all pipes of that class and diameter which have been manufactured shall be rejected and shall be rep]aced .entirely.

Any pipe or fitting which fails any of the quality control tests which are to be carried out on each and every pipe or fitting shall be rejected. In the event of any pipe failing any of the remaining tests outlined above that pipe shall be rejected and the relevant test shall be carried out on a further ten pipes of that class and diameter. If anyone of these ten pipes fails than the manufacture of pipes of that class and diameter shall cease and the Owner/Owner's Representative reserves the right to reject all the pipes of that class and diameter

Thermal insulating materials

Materials shall be tested for bulk density, specific heat, compressive strength, fire resistance under pressure, service temperature limit in accordance with VDI 2055 or equivalent standards.

0.7.2.2 Tests at site

0.7.2.2.1 General remarks.

The equipment to be supplied under the Contract shall be tested at Site during erection and initial operation. These tests shall prove whether the equipment meets the requirements of the Contract and the safety conditions, whether it has been executed with satisfactory workmanship and whether the equipment is in 'conformity with the prevailing standards and regulations as well as with the present state of modern technology.

Where manufacture or finishing is done at site, tests and inspections shall be conducted as a replacement for an appropriate workshop test. The preliminary check-out and test runs, the trial operation, the initial operation, the reliability test run and the performance tests shall be carried out by the Contractor's personnel in the presence of the Owner and the Owner/Owner's Representative.

Acceptance test readings shall be taken with calibrated instruments.

Waiving of any tests shall not release the Contractor of his responsibility to fully meet the requirements of the Contract.

0.7.2.2.2 Hydraulic tests

Unless otherwise stated in the specifications or in the relevant standards and codes, hydraulic tests at site shall generally be carried out on complete items of plant, where applicable. This may, at the discretion of the Owner/Owner's

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Representative and as far as applicable, include steam, water, air, gas and oil carrying pipe work.

0.7.2.2.3 Test runs and functional tests

Test runs and functional tests shall be carried out on individl1al equipment where practicable to prove the reliability and the correct functioning of the component and its compliance with the stipulations of the Contract.

Rated operating conditions shall be simulated if possible otherwise appropriate conversion factors shall be applied.

0.7.2.2.4 Visual inspection, checking of dimensions, test instruments

The Owner/Owner's Representative may from time to time make visual examinations and may check the dimensions of plant equipment and the conditions under which it is manufactured or erected at the Contractor's or Sub-Contractor's premises to make sure that it complies with the relevant specifications and drawings.;

Unless the calibration of test instruments and gauges is certified by recognized statutory institutes, they shall be calibrated at the premises and in the presence~ of the Owner/Owner's Representative or their authorized representatives. Test calibration certificates shall be submitted for each test instrument.

0.7.2.3 Manufacturing tests

0.7.2.3.1 Welding

Welding procedures shall be qualified in accordance with the requirements of the construction code/specification for the item of plant concerned and in the case of critical plant items the tests shall be witnessed by an internationally recognized inspection authority.

Welders shall be qualified in accordance with the requirements of the construction code/specification for the item of plant concerned for all types/positions of welding he may perform.

A system of positively identifying the work of each welder shall be maintained and any welder whose work is the subject of multiple rejections shall be required to undergo a requalification test. Any welder failing the retest may, at the discretion of the Owner/Owner’s Representative's Representative be disqualified from further welding on items under this contract.

Welded fabrications shall be stress relieved when specified by the applicable standard or for dimensional stabilization prior to machining.

Copies of temperature charts referenced with load items shall be included in the test certification supplied for the relevant items.

All welds shall be visually examined and shall be of smooth contour, free from cracks, undercut and other significant defects. Wherever possible the interior of tubes etc. shall be examined using a suitable optical device where necessary.

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Fillet welds shall be checked for size using suitable gauges which shall be available for use on request by the Owner/Owner's Representative's Representative during an inspection visit.

Non-destructive examination of pressure and vacuum containment welds

Welds shall be non-destructively tested in accordance with the construction standard applicable to the item of plant. In addition the requirements of the following Table shall be observed. This table shall also apply in cases where the standards used for design and construction of an item of plant does not specify the quality requirements for welds. Fault limitations to be subject of agreement with the Owner/Owner's Representative's Representative prior to fabrication.

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TABLE Non-Destructive Testing

Type of Steel Design factor

Wall thickness

Inside diam

Type and Extent of non destructive testing Remarks

(shell) (mm) (10m) Butt nozzle Fillet

C and C-Mn steels with C content not exceeding 0.25%

≤ 0.85 ≤10 all - - -

Only applicable to: Atmospheric systems (excluded systems, which handle chemicals, toxics or flammable media).

≤ all 10%R - -

>40 all 100% R 10%M 10%M

> 0.85 ≤40 ≤ 100 10%R - -

> 100 100% R IO%M 10%M

>40 all 100% R 100% M 100%M Test after stress relief

C-Mn steels with C content 0.25 to 0.35% and C 1/2 Mo steels

≤30 all 10%R 10%M 10%M Applicable below 50 bar

all > 30 all 100%R 100%M 100%M Test after stress relief

Low alloy steels except CrMoV and 2 CrMo

all all all 100% R 100%U 100%M Test after stress relief

CrMo V and 2CrMo steels and 12% Cr ferritic/martensitic steels

all all ≤100 100% R 100% M 100%M Test after stress relief

> 100 100% R� 100%M 100% M Test after stress relief

100% U 100%U

* Radiographic examination may be omitted if done on as-welded joint

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Type of Steel Design factor Wall

thickness Inside diam Type and Extent of non destructive testing Remarks

(shell) (mm) (mm) Butt Nozzle Fillet

Austentic Stainless Steels ≤ 0.85 ≤ 15 all - - -

Not applicable to: Butt welds made from one side only Operating temperatures exceeding 200°C

≤30 all 10% R - -

> 30 all 10% R 10% D 10% D

≤ 100 10%R - -

>0.85 ≤30

> 100 100%R 10%D 10%D

> 30 all 100%R 100%D 100% D

Legend:R = Radiographic examination U= Ultrasonic examination M=Magnetic particle examination O= Dye penetrant examination

Note:

1. Where 10% examinations are shown for pipe work under 100 mm diam bore this shall be the circumference of 10% of the welds by each welder selected at random with a minimum of one per welder.

2. Where 10% examinations arc shown for vessels or large diameter pipe work this shall be 10% of each weld length and must include all intersections of longitudinal and circumferential welds.

3. Where partial exam' at ions reveal rejectable defects, adjacent welds or areas of weld shall be examined. In the event of rejectable defects being found welds shall be subject to 100% examination.

4. Welds in clad materials shall be tested in accordance with the requirements of the base material and the surface of the overlaid welds shall be dye penetrant tested throughout the length.

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Non-destructive examination of structural welds

Welds shall be non-destructively tested in accordance with the construction standard applicable to the item of plant. Where appropriate the following requirements shall also be observed:

• Magnetic particle testing of the tension side welds In major fabricated girders and sections .

• Ultrasonic examination of heavily restrained welds (e. g. cruciform joints) where there is a risk of lamellar tearing in the parent material.

Weld repairs

Unacceptable defects observed by visual examination or indented by non-destructive testing shall be completely removed by chipping or thermal gouging and grinding. The resulting excavation shall be crack detected prior to rewelding.

Details of the original defects and repair shall be recorded.

Repaired welds shall be subjected as a minimum requirement to the same inspection requirements as the original welds and test records should indicate that a repaired weld is referred to.

0.7.2.3.2 Pressure testing

All items subjected in service to internal pressure or vacuum shall unless otherwise agreed be pressure tested in the manufacturer's works and prior to any internal or external coating.

Hydrostatic testing

All pressure vessels inserts or other parts of such vessels which are subject to an internal pressure or vacuum during operation shall undergo a hydraulic or other approved test. Unless otherwise stated in the specification the test pressure shall be maintained for a sufficient period to permit complete examination by the inspector.

Should it be necessary to carry out repair welding on stress-relieved equip-ment, it must undergo a stress-relieving process again. In all such cases the hydraulic test must be repeated.

Particular attention must be paid to the temperature of water used for hydraulic testing which shall not be less than 20°C. Prior to testing, metal temperatures shall also not be less than 20°C. Where pressure parts 600 mm in diameter and above are being tested the hydraulic pressure shall be raised to the test pressure in stages during which the item shall be examined and all defects rectified before the full test pressure is reached.

Suitable water shall be used as the test media unless otherwise agreed and test pressures shall be in accordance with the applicable construction

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standard but if none is specified then the test pressure shall be 1.5 times the design pressure but not less than an overpressure of 3.5 bar. Test pressure of vacuum containment items shall be agreed with the Owner/Owner's Representative's Representative.

The test pressure shall be maintained for sufficient time to permit complete visual examination of all surfaces and joints and in no cases less than specified in the applicable construction standard.

The chloride content of water used for testing austenitic stainless steel items shall not exceed 30 ppm unless immediate flushing with water of this quality is done after the test.

Pneumatic testing

The Contractor shall apply pneumatic testing in cases where hydrostatic testing is impractical or undesirable. Safety precautions, test pressures/ duration and degree of prior non-destructive examination of the subject items shall be agreed with the Owner/Owner's Representative's Represen-tative.

Pnelm1<\tic or gas leak testing supplementary to hydraulic testing shall be applied in appropriate cases where specified by the applicable construction standard.

0.7.2.3.3Testing of corrosion protection

Surface coatings

Following tests have to be performed before, during and after coaling:

• visual inspection of blasted surfaces according to DIN 55928 part 4, annex 1

• checking of coating material • measurement of air humidity, air temperature and coating area

temperature (determination of dew point) • visual inspection of coating • checking of dry film thickness (DFT) • checking of adhesion.

Galvanized zinc coatings

Surfaces shall be visually inspected. Bare patches, lumps blisters or inclu-sions of foreign matter shall be cause for rejection.

Zinc coating thickness shall be determined non-destructively in accordance with DIN 50981 or coulometrically in accordance with DIN 50932. For coatings with a weight exceeding 900 g/m2 the coulometric test method specified in DIN 50932 shall be used.

Hard rubber linings

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Surfaces shall be visually inspected. Uneven surfaces, splits, blisters or inclusion of foreign matter shall be cause for rejection.

The thickness of linings shall be measured in accordance with VDl Standard 2539 or equivalent. A tolerance of + 10% is permitted for rubber coatings of 3 mm nominal thickness.

Hardness tests shall prove compliance with the rubber manufacturers standards.

The absence of pores shall be proved by the induction sparking test method. The potential used shall be 5,000 Volts for each nun of thickness plus an additional 5,000 Volts (i. e. potential of 20,000 Volts for 3 mm thick lining).

0.7.2.4 Mechanical equipment

Rotating units

Balance testing of rotating units

Each rotating unit shall be first statically balanced and then dynamically balanced (in the case of impellers this shall be done before and after mounting of the service rotor shaft). A check balance of items that have undergone over speed test shall also be made.

Vibration testing of rotating units

The vibration characteristics of rotating units shall be measured during performance tests. Locations of measurement and standards to be achieved shall, on request, be subject to agreement by the Owner/Owner's Representative' s Representative.

Pumps

Running tests and performance tests shall be conducted on all pumps:

Performance tests shall be conducted through the full operation range of the pump to closed valve conditions. Graphs indicating flow head, flow/power absorbed, flow/efficiency, flow/NPSH and speed shall be produced.

Results for feed pumps shall be assessed with reference to DIN 1944 class 1 (without construction tolerances), and results for other pumps to class II or III as agreed.

The lubricating oil used in the test shall be of the same brand and grade as that recommended by the manufacturer for service use.

Dismantling of the pump for visual examination of parts for damage following test shall be done when required by the inspection standard, when considered necessary by the manufacturer, or when requested by the

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Owner/Owner's Representative's representative witnessing the running or performance tests. Replacement of parts following test shall necessitate repeat testing.

Steam turbines

The turbines shall be completely assembled with their control, stop and governing valves on a suitable erection rig at the manufacturer's works and shall be carefully inspected and measured for manufacture and assembly tolerances. Functional tests shall be performed on the safety equipment (running with steam is not requested).

Important items of turbine control equipment which cannot be adequately tested during the main tests shall be separately bench tested.

Furthermore testing shall comprise:

• balancing and over speed test of the assembled rotor • measurement of radial clearances • assembling inspection.

Air compressors

Air compressors shall be tested in accordance with the requirements of BS 1571, class C.1 part 1, ISO 1217, ASME PTC-9 or VDI 2045 - sheets 1,2 and 3 or similar standards. Any request for deviation from the test condi-tions shall be accompanied by the manufacturers' proposals for the adjust-ment of the correction factors contained in the standard.

Tolerances will be allowed according to ISO/R. 541.

Cranes and hoists

Where size permits cranes and hoists shall be completely assembled at the manufacturers works and functional tests without load conducted.

0.7.2.5 Electrical equipment

Unless otherwise agreed, the electrical equipment shall be tested in accor-dance with the following recommendations. Alternatively, equivalent standards approved by the Owner/Owner's Representative's representative may be used, such as VDE. Type tests shall be made if type test certificates certified by an independent test authority are not available.

AC Switcher for voltages above 1 kV

IEC 694 Specifications for AC switcher for voltages above 1 kV

IEC 56 High-voltage alternating-current circuit-breakers

IEC 267 Guide to the testing of circuit-breakers with respect to out of-phase switching

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IEC 298 High-voltage metal-enclosed switcher and control gear

IEC 420 High-voltage alternating current fuse-switch combinations and fuse-circuit-breaker combinations

lEC 427 Report on synthetic testing of high-voltage alternating current circuit-breakers

Metal clad switcher

Proof shall be provided of ability to withstand fault arcs in accordance with amendment No.2 of IEC 298. Criteria no.1 to 6 shall be fulfilled. At least two complete cubicles shall be tested (one cubicle being an end cubicle). If the test has already been carried out on similar type switcher, type test certificates may also be accepted:

Compliance with the IEC recommendation shall be fulfilled if

1. The plant is designed to be so resistant to pressure that no parts are thrown out in the event of a short circuit.

2. The arc gases must be directed in such a way that they will not endanger persons standing near the plant.

High voltage fuses

IEC 282-1, IEC 282-2 High voltage fuses

Power transformers

IEC 76 Power transformers

IEC 214 On-load tap-changers

IEC 404-2 Magnetic materials

Current transformers

IEC 185(1966) Current Transformers

Voltage transformers

IEC 186 Voltage Transformers

Generators

IEC 34, VDE 0530, IEEE 115, ISO R1680 and VDI 2056

• Generator test report

Comprehensive test reports for the generators are to be compiled and submitted by the Contractor, which shall include:

• Description of the test method, equipment used and any limitations of

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the test plant.

• copies of the oscillographs recorded with appropriate calibration data

• open circuit saturation, short circuit and loss curves for the generator

• a performance chart of the generator (being a diagram of constant stator and rotor current curves plotted on rectangular axis of MV Ar and MW load) The recommended loading, stator core end heating and stability limits shall be shown on the chart.

• calculations of full load temperature rise for the stator, rotor and ex-citer. Any correction factors used to allow for different voltage current and cooling conditions shall be justified by reference to published lit-erature or to previous type tests.

• calculations of the efficiency of the complete generator at 100%, 75% find 50% load. Any correction factors for losses that could not be measured at routine tests shall be justified by reference to published literature or to previous type tests.

• calculations of machine parameters such as transient reactance and time constant, sub-transient reactance and time constant, short circuit ratio, synchronous reactance, negative phase sequence reactance, zero sequence reactance capacitance and also the harmonic analysis of the neutral current.

• circulation of full load excitation of the machine at rated power factor lag1i.ing and at unity power factor, excitation V curves .

• Routine tests on generator

• Generator rotor

• ultrasonic examination

• mechanical balance coupled with exciter rotor

• over-speed test coupled with exciter

• Measurement of 50 Hz rotor impedance

• Generator assembled:

• three phase short circuit characteristic test and current balance check

• dielectric test

• measurement of insulation resistance

• measurement of winding resistance and resistance check of tem-perature detectors

• open circuit characteristic test and voltage balance, phase sequence

check

• segregation of mechanical loss and core loss

• segregation of stray load loss

• efficiency calculation

• unbalanced load test for negative-phase sequence and zero se-

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quence reactance

• shaft voltage measurement

• oscillographing of verified voltage wave form and harmonic (,lIlaly-

SIS

• measurement of vibration

• polarization index

• tan delta measurement of complete winding

• bearing insulation resistance .

• Type tests on generator as far as type test certificates are not avail-able

• sudden short circuit test at reduced voltage (30%, 50% and 70% of rated voltage), extrapolated to 100% voltage

• equivalent heat run test consisting of windage and friction heat run, open circuit heat run at 105% rated voltage, short-circuit beat run at rated line current, open-circuit heat run at rated line voltage

• measurement of open-circuit direct-axis transient time constant

• noise measurement

• moment of inertia

• measurement of excitation response time�

• overall characteristic coupled with generator and A VR cubicle at no load

• applicable to assembled unit consisting of generator, exciter and voltage regulator, may be carried out on site

• Routine tests on generator exciter (as far as applicable)

• resistance of windings

• insulation resistance

• high voltage tests

• short-circuit characteristic

• no-load characteristic

MV Motors

IEC 34, ISO R 1680, VDl 2056

• Type tests (each motor type) as far as type test certificates are not available

• measurement of starting current and torque

• efficiency measurement

• heat run test

• noise measurement

• Routine tests (each motor)

• measurement of winding resistances

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• no-load short circuit measurement

• dielectric test

• measurement of insulation resistance

• over speed tests

• check of motor vibrations

Low voltage switchgear IEC 158 Low voltage control gear

IEC 947 Low voltage switchgear and control gear

IEC 439 Low voltage switchgear and control gear assemblies

IEC 529 Degree of protection provided by enclosures

IEC 337 Control switches (low-voltage switching devices for control and auxiliary circuits, including contactor relays)

VDE 0641 Specifications for circuit-breakers

VDE 0170/0171 Electrical apparatus for potentially explosive atmos-pheres

VDE 0660 Part 1

Regulations for low voltage switchgear

VDE 0670 Part 2 Specifications for AC switchgear for voltages above 1 kV

Capacitors IEC 70 Power capacitors

lEC 80 fixed capacitors for direct current, using impregnated paper or paper/plastic film dielectric

IEC 103 Aluminum electrolytic capacitors for long life (Type I) and

IEC 143 Series capacitors for power systems lEC 358 Coupling capacitors and capacitor dividers lEC 384 Fixed capacitors for use in electronic equipment

Batteries, charging equipment and inverters

lEC 86 Primary batteries IEC 119 Recommendations for polycrystalline semiconductor rectifier

stacks and equipment lEC 146 Semiconductor converters

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Lamps and accessories

lEC 81 Tubular fluorescent lamps for general lighting service lEC 82 Ballasts for tubular fluorescent lamps IEC 155 Starters for fluorescent lamps IEC 598-1 Luminaries for tubular fluorescent lamps IEC 188 High-pressure mercury-vapor lamps IEC 262 Ballasts for high pressure mercury-vapor lamps lEC 400 Lamp holders and starter holders for tubular fluorescent

lamps Telecommunication installations IEC 215 Safety requirements for radio transmitting equipment Aerials

IEC 597-2 Methods of measurement of essential electrical properties

of receiving aerials in the frequency range from 30 MHz to 100 MHz

IEC 169 Radio-frequency connectors IEC 492 Measuring methods for aerial rods VDE 0855 Part 1 Regulations for aerial installations

Power installations up to 1000 V

IEC 64 VDE 0100 Regulations for the construction of power installations with

rated voltages below 1000 V VDE 0107 Regulations for setting up electrical installations in ,rooms

for medical purposes . VDE 612 VDE Specifications for electricity distribution units for use

on construction an building sites at rated voltages up to 380 V AC and rated currents up to 630 A

Power installation above 1000 V IEC 60 high-voltage test techniques

VDE 101 Regulations for the construction of power installations with rated voltages above1 k V

IEC 298 BV metal-enclosed switchgear and control gear (incl. amendment no. 2 "Internal Arc Test")

Protection equipment

Equipment for modular numeric protection systems (e.g. generator, distance, bus

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bar, protection, etc.) pre-assembled in the relevant standardized boards I cubicles etc. shall be tested in the manufacturers workshops as far as wiring and proper function is concerned. Simulated inputs (binary signals, current and voltage inputs from test power supplies) shall be used.

0.7.2.6 Control and monitoring equipment

All control and monitoring equipment shall be tested at the manufacturers' works before dispatch to site. Certificates shall be issued for

• synchronizing units • flow evaluators

On request the correct operation of equipment with specified temperature and humidity limits shall be demonstrated .by tests conducted within the limits.

Unless the calibration of test instruments and gauges is certified by recognized statutory institutes, they shall be calibrated at the premises and in the presence of the Owner/Owner's Representative or their authorized representatives. Test calibration certificates shall be submitted for each test instrument.

Electrical measuring instruments

All electrical measuring instruments shall be tested in accordance with the following rules and regulations. Alternatively, equivalent standards approved by the Owner/Owner's Representative's Representative may be used.

VDI 0410 Specifications for electrical measuring instruments

IEC 51 Recommendations for direct-acting indicating electrical measuring instruments an their accessories

IEC 258 Direct-recording electrical measuring instruments and their accessories

IEC 414 Safety requirements for indication and recording electrical measuring instruments and their accessories

Electrical remote indication

Meters for active power, reactive power and similar remote indication equipment:

VDE 0418 Regulations for electric integrating meters

IEC 338 Telemetering for consumption an demand

Calibration tests

The Contractor shall conduct calibration tests of the following instruments and equipment:

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• all local indicators over the full range of the indicator

• all recorders over the full range of the recorder

• all binary transmitters over the full range including initial setting

• all remote indicators over the full range of the indicator

• all transmitters over the full range of the transmitter

• one of each type of indication loop with circuit resistance of the loop increased to a value which is equal to the highest value expected, and under worst case operating conditions

• all superheated steam thermocouples

• one of each type of thermocouple or resistance element

• all kinds of analogue transmitters over the full measuring range

• all modules and subassemblies for measuring and control e.g. analogue limit monitors, flow evaluators, function generators

• all quantity meters

• all synchronizing units according to IEC standards

• the actual dimensions of all orifices, nozzles, venturi nozzles have to be measured and certified by an independent authorized specialist.

Closed-loop control systems

All main closed-loop control systems shall be tested for polarity and func-tion in accordance with the applicable standards. Control valves shall be tested in accordance with mechanical functional tests on control valves and shall be performed with the actuator mounted (open to closed position and vice- versa). Actuators shall be subject to mechanical and electrical function tests.

Sequence logic equipment

All sequence logic equipment shall be tested using simulated inputs.

Alarm annunciator and fault printing s)'stem

The alarm annunciator and fault printing system shall be tested using simulated inputs.

DCS system

The system shall be thoroughly tested at the manufacturers' workshops before dispatch to site. Test programs shall be devised and these shall subsequently be made available to the Owner/Owner's Representative's Representative. Tests shall be made to ensure that the system operates correctly within the ambient conditions as specified by the manufacturer and that if these conditions are exceeded, Le. in the case of failure of the airconditioning system, that the system will automatically fail safe and that

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neither hardware nor software will be damaged.

0.7.3 Testing at site during installation

0.7.3.1 Erection tests

General

During erection all required erection tests as well as final erection checks of the mechanical completion of the systems and part there of have to be performed.

After successful mechanical completion Mechanical Completion Certifi-cates will be issued.

The activities necessary for mechanical completion shall included but not be limited to following testing:

• visual inspection after unloading at site

• checking of completion of relevant systems

• completion of buildings and civil works

• test of ventilating and air-conditioning units

• alignment of rotating equipment coupled on site

• safety audit

• testing of site welds (non-destructive examinations)

• pressure testing, leak tests, tightness tests

• checking of pipe hangers, supports, guides, etc.

• pipe line and equipment flushing and cleaning

• chemical protection of piping systems

• checking of coating

• testing of cranes and hoists

Electrical equipment tests

The following checks and tests measurements shall be made:

• screwed connections for correct assembly

• terminals and terminal connections for correct assembly

• checking of earthing connections and testing of earthing resistances

• measurement of insulation values

• verification of neutralization conditions

• fire-proof partitioning

• marking, inscription, provision of designation plates

• rotating-field measurement

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• phase coincidence with 2 half-bus bars

• voltage checks'

• polarity checks in the case of DC voltages

• fuses, over current trips, short-circuit trips, time settings, relay settings

• switchgear and transformer oil levels

• safety signs and warning signs

• setting indicators, revertive (check-back) signals to the central control room etc.

• checks on wiring and cabling for conformity with the constructional circuit-drawings and plans

• checking and functionality testing of electrical systems according to IEC standards

• tests on the generator main bus bar

• checking for the gas-tightness of individual main connections system

• tests on the earthing and lightning protection system

• acceptance tests and measurements of the earthing installations in accordance with DIN 57 141 and of the lightning protection systems in accordance with DIN 57 185

•tests on the lighting system • proof of the minimum new value of lighting densities, checking of

correct operation both electrically and mechanically.

0.7.3.2 Pre-commissioning tests

Preconditions for the commissioning are the issue of the Mechanical Completion Certificate and the availability of the accepted commissioning test program and the Contractor's commissioning procedures; The Pre--commissioning Checks cover the functional tests of the individual items and their alarm and tripping systems. Following tests shall be included:

Mechanical equipment

• individual pre-commissioning runs of all rotating equipment such as pumps, compressors, dosing equipment etc .

• functional tests of the mechanical equipment • testing and adjustment of safety devices.

Electrical equipment

As far as not already covered by the erection tests the pre-commissioning tests shall cover:

• voltage tests • trip tests •functional tests of the equipment

Control equipment

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• Calibration tests of instrumentation, loop checking, functional testing of control equipment, interlocks, protection inputs, etc.

0.7.3.3 Tests on completion

Preconditions of the Tests on Completion are the successful completion of the pre-commissioning checks of all items of the whole system and the satisfactory completion of the commissioning activities. On completion of each commissioning activity to the satisfaction of the Owner/Owner's Representative/Owner/Owner's Representative, the commissioning schedule shall be signed and dated by the Contractor and countersigned by the Owner/Owner's Representative.

The Tests on Completion shall prove that the plant is prepared and adjusted to ensure the correct functioning of the individual components and of tile complete plant.

After successful completion of the Tests on Completion the "Authorization �to Start Reliability Test Run" shall be signed.

The Tests on Completion shall cover at least following tests:

• protection tests

• operation of selected turbine train protection devices including the following as a minimum

• fire protection

• boiler protection

• steam turbine protection

• generator protection

•transformer protection

•auxiliaries

• method of alarm/trip condition reset for subsequent starting

• operation of auxiliary systems

• method of changeover of main equipment to standby equipment prior to turbine starting (see start-up tests) and during normal turbine generator operation for lubrication and control oil system and cooling systems

• operation of fire protection systems

• isolation procedures

method of isolation of plant equipment for safe shut-down and maintenance procedures including as a minimum

• HV station and unit supplies

• LV supplies

• oil systems (lubrication and control)

• fire protection systems

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• protection systems/settings, in accordance with agreed design and the requirements of the transmission system

• start-up tests

• normal automatic start to preset load

• staged automatic including start to synchronous speed, manual synchronizing (including synchro-check), automatic synchronizing, manual and automatic loading

• starting with stand-by auxiliaries

• operation of all auxiliaries

• verification of start up times and loading rates of power units, steam

generators and multistage flash units at various downtime conditions ~

• power unit, to test partial and full load rejection to demonstrate

• full load rejection tests to measure transient maximum speed and steady state speed at normal governor droop setting

• method of resynchronize to be demonstrated

• turbine bypass operation capability

• Power unit/Plant, to verify and check

• operating stability when operated between 30% and 100% nominal load conditions with load variations by increasing or decreasing the electric load

• demonstration of the capabilities of the Power Units to operate at rated voltage and frequency, at power factors and reactive conditions between. 0.85 (lag) and 0.95 (lead)

• start-up tests of the Plant equipment, facilities and systems including checking of automatic change-over of standby facilities�

• verification of vibration and noise emission guarantees

• environmental monitoring equipment, water quality monitoring equipment, functioning tests and verification of guarantees

• demonstration of the teledispatching and telemetering systems.

• verification of active power response and voltage control response according to the requirements specified in the network connection conditions

• demonstration of proper controlling, monitoring and recording according to the requirements of the grid code

• verification of completeness of scope of supply

• verification of 24 hours uninterrupted MCR operation. As precondition to the start of the reliability test run no adjustments, manual operation and other intervention are permitted during this verification.

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0.7.4 Reliability test run (Initial Commercial Operation)

After successful completion of Test on Completion and after relevant test protocols have been accepted by the Owner/Owner's Representative, the Contractor shall be allowed to prepare the Plant Unit for the reliability test run. Reliability test run is also named as Initial Commercial Operation.

The reliability test run shall be carried out for the power unit including related equipment and systems and shall last for a period of six (6) weeks each.

During the specified period, plant unit and related equipment and systems shall be operated continuously and in accordance with the prevailing power requirements of the transmission system or as required by the Owner/Owner's Representative. If possible with reference to the grid, Unit shall run at MCR.

The reliability test run will not be deemed to be completed unless the relevant performance tests have been made.

In the event of interruptions to the reliability test run, for which the Contractor is responsible, the length of the reliability test run can be extended by a period equal to the total duration of the interruptions. If such an interruption lasts more than 48 hours, the reliability test run shall be restarted, after repairing the defect. The reliability test run may be interrupted on three occasions, provided that the total hours of interruption do not exceed 48 hours and that the Owner/Owner's Representative is notified of the interruption in good time. Minor adjustments to the control system are permitted with previous agreement of the Owner/Owner's Representative.

0.7.5 Performance tests

After positive conclusion of the reliability test run period the Contractor shall demonstrate by means of performance tests that the plant units and the Plant including related equipment and systems can be tested to prove the guarantee parameters.

Lower output and heat rate

The overall outputs under differing operating conditions shall be determined and achievement of the performance guarantees given in the relevant schedules shall be evidenced.

Performance tests shall be conducted in accordance with following standards:

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• the boiler DIN 1942 (or ASME) • generator ISO 2314 • steam turbine DIN 1943 (or equivalent

ISO or ASME) • transformer IEC 76.

The curves required for the correction of the power output and specific heat rate to the site specified ambient conditions shall be listed in the technical schedules of the Plant performance and gas turbine performance.

All margins required for instrument inaccuracies and for all other reasons shall be deemed to be included in the guarantee figures.

Derating curves for the Plant performance shall be submitted by the Contractor with tender. The curves shall show the Plant's degradation in power output and heat rate versus equivalent operating hours. The curves shall be applicable up to and including major overhaul.

All special instrumentation shall be calibrated for the test and supplied by the Contractor. Meter accuracy shall be as determined mutually by the Owner/Owner's Representative.

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0.8 Abbreviations

In general when using abbreviations care shall be taken to prevent confusion with KKS numbers . ASC average site conditions AC alternating current AVR automatic voltage regulation COD commercial operation date DC direct current DCS distributed control system extra EHV high voltage (400 kV) EMC electro magnetic compatibility ESP electrostatic precipitator GRP glass fiber reinforced piping H.R.C high ruption capacity fuse BV high voltage I&C instrumentation and control IR infra red KKS Kraftwerks-Kennzeichnungs-System ( PPCS) (Power Plant Coding

System) LHV lower heating value MNCL minimum continuous load MCR maximum continuous rating MCS mean cold season (winter) site condition MHS mean hot season (summer) site condition O&M operation and maintenance OHL overhead line PC pulverized coal PPCS Power Plant Coding System (~ KKS) SCADA supervisory control and data acquisition SWG switchgear (LV and MV) SWY switchyard (HV)

TOV Technischer Oberwachungsverein (Technical Surveillance Association)

DIN Deutsche Industrie Norm (German Industrial Standards)

VDE Verein Deutscher Elektroingenieure (German Electrical Engineers Society)

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Steam Generator Plant

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Table of Contents

B1. Steam Generator Plant

1.1 General

1.2 Scope of Supply and Services

1.2.1 Boiler pressure parts

1.2.2 Drain and blow-down system

1.2.3 Firing and grinding system

1.2.4 Start-up and back-up firing system operating on

diesel fuel oil

1.2.5 Heating surface cleaning system

1.2.6 I (one) boiler wall inspection lifting equipment

(for two steam generators)

1.2.7 Refractory setting, thermal and noise insulation

1.2.8 Steel structure for steam generator with auxiliary

plants

1.2.9 Boiler accessories

1.2.10 Auxiliary steam boiler

1.2.11 Boiler and steam/water system cleaning

1.3 Special Technical Requirements

1.3.1 General

1.3.1.1 Design

1.3.1.2 Steam generator plant modes of operation

1.3.1.3 Fuel

1.3.1.4 Feedwater

1.3.1.5 Steam purity

1.3.2 Design and construction requirements

1.3.2.1 General

1.3.2.2 Steam generator

1.3.2.2.1 Furnace and connection pass for dry slag/ash extraction

I.3.2.2.2 Pressure parts

1.3.2.2.3Superheater (SH) and reheater (RH)

1.3.2.2.4 Economizer

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1.3.2.2.5 Evaporator with steam drum

1.3.2.2.6 Supporting tubes and supporting bars

1.3.2.2.7 Headers

1.3.2.2.8 Safety valves, fittings and mountings

1.3.2.2. 9 Miscellaneous mountings

1.3.2.2.l0 Water level indicators

1.3.2.2.11 Sampling system

1.3.2.2.12Integral pipework

1.3.2.2.13Heating surface cleaning system


1.3.3.1 Coal bunker

1.3.3.2 Coal feeders

1.3.3.3 Coal mills/pulverizers

1.3.3.4 Pulverized coal burners (PC burners)

1.3.3.5 Distribution of pulverized coal

1.3.3.6 Primary air fan (PA fan)

1.3.3.7 Inerting system for pulverizers and coal pipes

1.3.3.8 Start~lIp and backup firing system operating on diesel fuel oil

1.3.3.9 Diesel oil tank

1.3.3.10 Slop oil tank

1.3.3.11 Filters

1.3.3.12 Pipelines, foam pourcr

1.3.3.13 Electrical, control and monitoring equipment

1.3.4 Auxiliary steam boiler

1.3.5 Inside cleaning of boiler pressure parts

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B1. Steam Generator Plant

1.1 General

Steam generator to be installed shall be of the natural circulation reheat type. The unit shall be designed for pulverized coal firing (PC firing), balanced operation and out door arrangement.

The Bidder has to check and to verify all relevant information as the basis for his offer.


The scope encompasses all supplies and services necessary for fulfilling the objective of the contract for 1 (one) complete coal-fired steam generator plant and their complete auxiliary equipment, even if individual items are not specifically mentioned below.

Steam generator and accessories consisting of:

1.2.1 Boiler pressure parts

Comprising essentially

• economizer with inlet and outlet headers

• evaporator system with steam drum, headers and down comers

• super heater and reheater with inlet and outlet headers

• 100% attemporator for super heater and reheater

• all internal water and steam pipes and headers

• all necessary drain-, purges-, vent- and blow-down pipes incl. valves concentrated at valve groups (double block valve)

• blow-off pipes for safety valves and start-up valve incl. silencer

• boiler mountings, valves and accessories:

• feed water shut-off valve and feed water control valve with electric drive, check valve incl. manual. operated control valve as bypass

• automatic condensate traps with bypass and stop valves

• complete drum-blow down valve group

• drum emergency drain valve with electric drive.

• local and remote water level indicator

• local instrumentation

• safety valves (2 x drum, 2 x super heater outlet, 4 x reheater outlet)

• start-up control and shut-off valves, each with electric drive

• live steam stop valve with electric drive

• sampling system for feed water, boiler water and live steam incl. coolers, piping and valves

• casing, frame and supports

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• buckstays, tie bars, stiffeners and pipe damps as required

• one complete set of doors and peepholes necessary for access, inspection and supervision including service air nozzles connecting piping.

1.2.2 Drain and blow-down system


• 1(one) continuous blow-down flash tank (atmospheric tank) incl. Cooling system, blow-off pipe, control valve and necessary equipment

• 1 (one) boiler drain flash tank with flanges, vent drain and connecting pipes.


• Coal bunkers as steel structures

• coal handling plants, including bunker isolating arrangement, feed chutes, mill downshafts and coal feeders with all electrical drives, fuel bed depth regulators, coal sampling points, remote sensors for electronic fuel bed depth and rotary speed checkback signals

• coal mills with motor, with shock absorbers, classifiers and special tools; Coal mill specification: Capacity= 70% through 200 mesh, Hardness Grinding index=75, raw coal moisture= 15%

• mill primary air fan(s) with silencers on inlet and delivery sides with electric motor

• seal-air fans with electric motor

• PC firing systems including low-NOx burners, PC distribution and delivery lines, combustion air register, regulating, adjustment and isolating dampers as well all drives, two PC sampling equipment incl. sieving device for each burner

• two PC sampling studs with air scaling connections for each PC pipe

• flame detectors for the PC firing system

• Automatic Coal mill’s hard coal/stone rejection system, via denseveyor/ positive pressure conveyor with 16 hrs storage and related others auxiliary, if necessary

1.2.4 Start-up and back-up firing system operating on diesel fuel oil

Comprising essentially:

• main isolation valves outside of the boiler area

• diesel fuel oil low-NOx burners

• electric ignition and flame detection installation

• pipework and valve stations inside the boiler area

• burner management system

• ignition and cooling air fans with motors

• analog and binary equipment

• flow meters for oil supply and return line and each burner

• local control station

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• oil trays

• diesel oil tank including unloading station

• oil piping and valves

• oil pumps, fillers

• slop oil tank

• slop oil pumps • slop oil pipes.

1.2.5 Heating surface cleaning system


• furnace wall steam soot blowers

• semi-stroke rotary steam soot blowers with retractable lance and electrical drive

• long retractable steam soot blowers

• main isolating valve with electrical actuators and steam pressure reduc-ing station with pipe work, instrumentation and valves for steam supply as well as temperature-controlled drain valves with electric actuators

• 2 (one as stand-by) cooling and sealing air fans

• automatic soot blower control and cabling of soot blowers and limit switches to the cubicles, cabling between electrical and control cubicles, including cable installation material (conduits, cable clamps, etc.)

• electrical cubicles with incoming feeder circuit breakers, motor protec-tion and indicators for power consumption, pressure, temperature, ad-vance and retract operation

• field switchboxes with interlocks for optional local operation

• automatic switch-over in the event of mechanical blockage.

1.2.6 1 (one) boiler wall inspection lifting equipment (for steam generator)

Comprising essentially: • lifting capacity 3,000 kg • one lifting winch • type external winch

From the lifting winch, which has to be designed as a double-driving drum winch, two hoisting ropes are to be transported.

• the system of sufficient guide pulleys.

• one working platform in light-metal construction The working platform should consist of several parts

The whole working platform is fitted with a guard plate on top. In addi-tion the working platform has to be fitted with:

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• 2 safety catches

• 2 drive limit stops

• plastic rollers to keep off the working platform from the boiler walls

• plastic wheels for transporting the working platform outside the boner plant

• The parts of the working platform are to be assembled by plug-and-socket connections.

• One electrical equipment mainly consisting of:

• switch cupboard at the lifting winch

• trip line for the working platform included are 2 conductors for a tele-phone connection

• control panel for the working platform with

• 2 connections for hand lamps 42 V

• connections for the proximity switches of the drive limit stop systems and the safety catches .

• mercury cut-out to limit the slanting of the working platform

• all necessary key buttons, conduit boxes and cross-cables

• 2 hand lamps, 42 V, 60 W

• transfer drum for the trip line

• two cantilever arms in Iight-metal construction

• two hoisting ropes and two safety ropes (steel ropes)

• accessories

• 2 hooks to fetch the safety ropes

• 2 movable transfer drums for the safety catches

• 2 auxiliary ropes to let down the safety ropes from the cantilever arms into the boiler

• 3 leading-strops to fasten the working platform at the boiler-walls in the range of the entrance openings

• special tools

• lay down construction on the furnace bottom.

1.2.7 Refractory setting, thermal and noise insulation


• moulded refractory lining and shaped fire bricks in the area of the burners, access doors and peepholes, etc.

• furnace moulded refractory

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• insulation and sheet cladding for thermal and noise insulation.

1.2.8 Steel structure for steam generator with auxiliary plants


• complete steel structure for boiler. coal bunker, lift shaft, pipe and conveyor bridges and for auxiliary equipment

• 1 (one) open stairway as connection between platforms (taking into account permissible escape route lengths)

• all necessary access galleries, stairways, ladders and platforms • protection sheds (or hoods) for all equipment located outside such as

fans, actuators, electric drives, etc. • roof and dust proof cladding for tripper conveyor • dust proof enclosure for all conveyor bridges.

1.2.9 Boiler accessories


• boiler inspection cradles for fast inspection and repair of combustion chamber and stock

• utility station for air, steam and water from connection branch of main distribution supply up to the consumer, including hoses, hose couplings and stop valves

• fire fighting equipment for steam generator, complete with all integral pipes, valves, nozzles, hoses

• equipment and provisions for stand-still conservation of the steam generator.

1.2.10 Auxiliary steam boiler (if required)

Existing 2 x 125 MW units have 1 (one) 10 ton/ hr capacity auxiliary steam boiler. If these capacity is not enough for the proposed 250 + 10% MW unit, then 1 (one) auxiliary steam boiler shall have to be supplied by the contractor.


• (one) auxiliary steam boiler fired with diesel fuel oil, complete as package with all systems and accessories including at least (to allow start-up and critical operation without any external supply of steam):

• economizer furnace and super heater • one forced draft fan • complete duct work from FD fan to the oil burners • oil burners • complete instrumentation, control and monitoring equipment burner

management • associated piping • feed Water system including feed water pumps • flue gas ducts from boiler outlet to the stack • steel stack.

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1.2.11 Boiler and steam/water system cleaning


• inside cleaning of pressure parts (boiling out and blowing out of coal fired boiler and auxiliary boiler).


1.3.1 General

The requirements specified under B0 "General Technical Specification and General Technical Requirements" are to apply, and, where applicable, further regulations from other sections of this specification.

The Special Technical Requirements under the Section B 1 refer to simplifying to boiler and accessories.

1.3.1.1 Design

The steam generator shall be of the radiant, natural circulation (single drum) water tube type with integrated reheater.

The unit shall be of the balanced draught design, i.e. with forced and induced draught fans.

The prescribed design and performance data of the boiler plant are listed in the Technical Data Sheets B1/FB.

It is to have provision for firing 100% of MCR pulverized coal and 35% of MCR design capacity with fuel oil firing for boiler start-up and low load backup firing.

The furnace enclosing walls and the enclosing walls of the heating surface section are welded gas-tight. The gas-tightness has to be tested. The furnace itself, the radiation pass and the enclosing walls of the convection heating surface sections are comprised of vertical membrane walls.

In order to compensate for any non-uniformities of flue gas temperature over the cross-section of the boiler, each of the superheater and reheater stages are separated into at least two parallel streams. The streams of the individual stages are diagonally connected to each other.

The temperature control for the superheater and reheater is achieved by means of spray attemperators which are located in the connection lines between the stages of the superheater and of the reheater.

In order to permit cleaning of heating surfaces during operation and which have become fouled by slag or fly ash, soot blowers have to be provided,

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Steam is used as the blowing medium for the furnace walls and for the convection heating surfaces.

The boiler is suspended from the roof of the steel support structure and thus allows for thermal expansion downwards during operation. The boiler enclosure is to be arranged as an extension of the boiler steel structure which shall be c1added with metal sheets.

Firing system

Coal is supplied to the boiler units via belt conveyors. The coal bunkers are charged by means of belt conveyors. It is planned that the belt installation be in one line .

Boiler unit has 4 coal bunkers each with a capacity suffices for 16 hours of operation at MCR and with design coal. It is planned to construct the coal bunkers of steel.

By means of the coal feeders, the coal is withdrawn at a controlled rate from the coal bunkers and supplied by coal feeders to the inlet chutes of the four coal mills (one standby). In these, the coal is pulverized, dried and classified. The coal is supplied to the burners via pulverized coal (PC) lines with distributors. The classifier temperature is regulated by mixing with cold air.

The main design criteria of pulverizer design has to be:

• MCR has to be generated by 3 pulverizers in service, burning design coal, without supporting oil

• MCR has to be generated by 4 pulverizers in service, burning worst coal, without supporting oil. When one mill is not available for operation due to maintenance reasons, its output can be substituted by diesel oil.

Further, the diesel oil is used for ignition, cold and hot start-up and for low backup firing.

The installation of low NOx burners is to be provided. As key measures for the abatement of NO x emissions by combustion modification, air and fuel staging. Flue gas recirculation can be incorporated, if necessary.

Air and flue gas system

The air and flue gas system is designed in a double flow path, each for 60% of MCR. Provision for later flue gas recirculation system for decreasing the NOx emission has to be provided, if necessary.

Air system

Combustion air is supplied by means of the FD fans, following which the air flow is separated into primary and secondary air. The primary air is further compressed by means of the primary air fans, following which part of the primary air is diverted to provide cold air for controlling the mill classifier

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temperature. For both the primary and secondary air, steam air preheaters are arranged upstream of the regenerative heater. With the steam air heater the combustion air is preheated sufficiently for there to be no danger of corrosion at the regenerative air preheaters in cold section. Following the regenerative air preheaters, the primary and secondary air is routed to the, mills or to the burners. Sufficient measurements for all air flows and all burners will be applied.

Flue gas system

Following their exit from the boiler, the flue gases flow to the regenerative air preheater, where they are cooled further and at the same time the primary and secondary air is heated up. Within the downstream EP, the flue gases are free of most of their dust burden before being routed to the stack via the ID fans.

Ash removal system

Bottom ash

In order to remove slag/ash from the furnace, submerged ash/slag scraper conveyors and crushers are provided. The ash/slag discharged via belt conveyor into ash silos. In order to maintain a seal in the furnace, dipper seal plates are attached at the slag discharge.

Economizer Hooper cleaning system with fluidizing air system in running condition

Fly ash

The fly ash from the EP and other points of the boiler where it collects is conveyed pneumatically to the loading storage silos outside the boiler area.

Sewage sludge

The lime slurry which are used for the power plants water pretreatment process and amounts as lime sludge can be delivered with the coal to the coal bunkers for burning it in the combustion chamber. Predrying of the lime sludge is recommended.

Slag type furnace

Slag type furnace for granulation of the ash can be offered, provided that the contractor shows evidence that he has already built at least 3 of such furnace type.

1.3.1.2 Steam generator plant modes of operation

Refer to part B0.2.6 (Mode of operation).

The steam generator with its auxiliary equipment is one of the principal components fixing the dynamic capacity limits of the Power Plant. In order to be able to follow the planned operation regime and above all the high requirements for frequency support, during the design phase all required

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measures shall be taken to ensure rapid availability after start-up and optimum load-following behavior.

The following start-up conditions shall be Possible:

• start-up of the cold steam generator and cold turbine

• start-up of the cold steam generator with the turbine still warm following outage of one or two days

• Start-up at any time of the warm or hot steam generator with hot turbine.

• start-up of the warm steam generator with cold turbine, if after a short steam generator operating time during which the turbine did not roll, the unit has to be started up new

• start-up with a feed water temperature of 50 - 70°C

• part-load operation with just one mill and with backup firing.

Boiler operation without the HP feed water preheaters shall be possible.

The excess air at the outlet of the combustion chamber when burning coal shall be approximately 20% within the load range from 40% to 100% of MCR.

• The superheater outlet temperature shall be kept constant within the load range from 60% to 100% of MCR with feed water injection.

• The reheater outlet temperature shall be kept constant within the load range from 70% to 100% ofMCR with feedwater injection.

• The exhaust gas temperature at MCR when burning coal with 20% excess air shall be 150°C at air preheater outlet.

1.3.1.3 Fuel

The steam generator and its auxiliaries shall be designed for pulverized coal firing. Diesel oil shall be used only for start-up and back low load up firing. Typical analyses of coal is given in the Annex.

1.3.1.4 Feedwater

The steam generator of natural circulation water tube type shall be fed with turbine condensate and a small percentage of make-up water. The feedwater shall be thermally deaerated and treated with volatile chemicals. Its chemical properties shall be within the limits of the "VGB Directives for feed and boiler water of steam generators" (latest edition).

Thorough supervision of feed water entering the steam generator shall be provided.

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1.3.1.5 Steam purity

During continuous operation the properties of the steam leaving the super' heater shall not exceed the limits of the "VGB Directives for feed and boiler water of steam generators" (latest edition).

1.3.2 Design and construction requirements

1.3.2.1 General

The steam generator and its accessories shall be designed for outdoor installation with a suitable weather protection, insulation to completely protect the boiler and its accessories.

The design of the steam generator and of the auxiliary equipment shall envisage the life time of the Power Plant under the prevailing climatic and operating conditions to be 30 years.

All noise emitting equipment shall be duly protected by silencers, sound absorbing jacketing, insulation, etc. in order to meet the requirements as specified in Section B06 and B07.

The pattern of the normal load jumps as dictated by the interconnected grid are sudden due to load shedding and line faults. The Bidder shall describe measures he has taken in the designing of the steam generator to facilitate and secure these operating conditions.

Sufficient space shall be provided in the convection pass of the steam generator for possible correction of the heating surface in case practical results suggest such corrections to be necessary. The amount of space shall be consider possible future installation of approximately 10% of total superheater, reheater, economizer and air preheater heating surfaces.

The design of the steam generator and its auxiliaries shall consider the possibility of preservation prior to or after commissioning by providing all necessary connections and provisions as for example

• heating of pressure parts by auxiliary steam • introduction of suitable chemicals • electric heating of motors, cubicles.

The Contractor's method of preservation shall be subject to the Client's approval.

1.3.2.2 Steam generator

The steam generator to be installed shall be of natural circulation water tube type and designed for dual coal and diesel oil firing. The unit shall be

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of balanced furnace design with two regenerative air heaters, two FD fans and two ID fans.

1.3.2.2.1 Furnace and connection pass for dry slag/ash extraction

The furnace shall be of the fully water-cooled welded membrane wall type. The volume and dimensions of the combustion chamber shall prevent flame impingement or excessive heat transfer upon any portion of the water-cooled walls or other parts of the furnace enclosure at all operating conditions.

The furnace size shall provide sufficient space for flame development and shall allow complete and efficient combustion of the fuels specified before leaving the furnace. Central or division walls are not accepted.

The configuration of the furnace shall be so that the air/flue gas flow will reach all its parts and there will be not dead zones in which the formation of an explosive gas/air mixture can occur.

The furnace outlet temperature (at first bundle heating surface inlet) shall be selected under consideration of the initial deformation temperature of the fuel with the worst ash specified.

The design will consider that no fouling in space superheaters for these coals which can affect the reliability of the unit will occur. The supplier should present detailed design of furnace� and gas outlet temperature profiles to the purchaser during the design stage of the project for the whole band width of all fuels specified.

The furnace and burners shall be such that when burning the types of fuel specified and under all conditions of load up to the maximum output, there shall be no flame impingement on any surface of the furnace walls and no accumulation of slag on the walls, tubes or hoppers or other part of the boiler units that will interfere with the continuous operation of the units.

Furnace design shall be designed primarily taking into consideration the operation of the boilers on Barapukuria coaL

No additives are to be used to improve combustion, fouling problems, corrosion problems or other reasons.

The furnace and convection pass shall be equipped with all necessary access and inspection doors, access doors being located at both side walls. A sufficient number of observation windows shall be provided in the appropriate positions to allow for visual observation of the flames, the combustion process and the roots and the tip of the flame of each burner.

Numbers of TV cameras and suitable position of openings shall be so that it will be possible to observe the root and the tip of each flame, as well as the number of burners in operation.

The combustion chamber shall be welded flue gas tight whenever possible,

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the wall panels shall be reinforced by buck stays so as to withstand a flue gas pressure inside the combustion chamber and all flue gas pathes of at least ±70 mbar:

Access doors, viewing ports and peepholes shall be completely leaktight against flue gas and accessible from the flooring or platform specially provided. Access doors shall open and close without difficulty. Grips of round steel bar shall be provided over the access doors. It should be possible to replace sight glasses during operation.

All openings in the wall of the furnace shall be duly protected against deterioration by heat.

All loads of the furnace with framing and insulation as well as burners and ductwork shall be led by the evaporating tubes and anchors to the support-ing steel structure at the boiler top casing without causing bending stress in pressure parts.

Slag/ash removal from the boiler shall be by means of a submerged slag/ash scraper extractor. Ash falling into the hopper of the flue gas blank pass and regenerative air preheater shall be directed to the wet ash scraper extractor. The water in the slag extractor shall flow in a circuit via a cooler, and shall be cooled and conditioned so that continuous or discontinuous blow down is not necessary.

Provision shall be made at the steam generator for the attachment of furnace inspection equipment. Inspection and repairs from inside of all walls above the furnace bottom shall be possible.

The following are required to ensure a good combustion at all loads:

• stable ignition across the total load range • complete furnace burn-out rate • furnace temperature below the ash melting temperature across the load

range without big slag pieces • high fly ash retention figure • low NOx emission.

Particular attention is to be paid to the following characteristics in the furnace:

• even flue gas distribution for intense heating of the furnace area • good reswirling of the flue gas to the burner section to stabilize the

ignition of the pulverized coal; • special deflection and removal of the flue gas flows for optimal fly ash

retention; • no or low CO content in the flue gases.

An optimal solution for the furnace design and shape is to be found by means of special flow tests-'1' model experiments), Further it is to be ensured that the ash carried in with the coal extract heat from the flue gas considering possible change of flue gas profile which can lead to a decrease in the end temperature of the furnace.

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1.3.2.2.2 Pressure parts

The furnace hopper, the furnace, the evaporator membrane walls and the membrane walls enclosing the convection tube bank shall be executed in vertical tubing, welded completely gastight and observing the limits of the specified design parameters. Tube penetrations through the membrane walls as well as through the furnace roof shall likewise be executed in a completely gastight welded design (welding sleeves).

All pressure parts of the steam generating unit shall be designed, manufac-tured, constructed and tested in accordance with the applicable standards. The boiler pressure parts shall be completely self-drainable.

The Bidder shall submit with his Bid a material diagram indicating for each single pressure part whether it is heated by flue gas or not, the following characteristics:

• the highest flue gas temperature, • the highest permissible steam temperature • the design pressure, • the working pressure, • the highest permissible material temperature, • the design material and wall thickness of the part • code number of the material • temperature margin between operation temperature and calculation

temperature.

All stress calculation of the pressure parts shall be allow for the lifetime of the plant as stated elsewhere with at least 50 shut-down and start-up per year.

All tubes material shall be fabricated from hot or cold finished seamless material and shall be ultrasonic tested.

Headers shall be of forged or seamless drawn steel. They shall be provided with inspection stubs on the ends. Headers and spray attemperators shall always be located outside of the flue gas stream and shall be fitted with closure elements to permit their direct inspection without any auxiliary equipment.

In addition, the spray attemperators shall be installed outside of the sheet metal casing and easily accessible.

Grey cast iron may not be used in any pressure part.

The steam drum, headers, pipes and tubes shall be of approved construction and manufacture, the suspension system and seismic precautions shall be particularly indicated.

Supporting tubes for heating surfaces exposed to flue gas temperatures of more than 400°C shall be cooled by feedwater or steam.

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To avoid high temperature corrosion the connecting piece between supporting tubes and heating surface shall be kept short as possible so that their metal temperature will not exceed 570°C.

The wall thickness of the tubes shall allow for the thinning of the tubes bends. All tubes of the convection heating surfaces shall be arranged in line. The transverse spacing of all tube banks shall not be smaller than double the tube diameter.

Wherever practicable the boiler shall be of completely welded construction. In designing the steam generator the contractor shall minimize the number of necessary fields welds. All components shall be shop prefabricated to the largest extent. Headers shall be provided with stubs which are of sufficient length to ensure that the heat of the welding process will not ,affect the material of headers. All abutting tube ends shall be suitably prepared for welding. All work on site, in particular welding and heat treatment, will be subject to the same regulations as for Contractor's workshops.

All parts carrying hot media which are designed to specific creep rupture strength shall be designed to provide a service life time of200, 000 hours.

1.3.2.2.3 Superheater (SH) and reheater (RH)

Superheater (SH) and reheater (RH)

The flue gas temperature at the inlet of the supporting tubes upstream the first platen SH stage shall not exceed 1200°C (average measured 'versus boiler width) considering fouling during operation. The flue gas temperature at the inlet of final SH stage with normal fouled heating surfaces shall be less than 1050°C.

The high pressure SH shall be divided at least into two parallel flows and each flow shall consist of at least three (3) subsequent stages with intermediate spray attemperators.

The RH shall be divided into at least two parallel flows with spray attem-perators between the RH stages. RH system isolating valves shall be provided for leakage test of reheater.

SH and RH shall be of the self-draining type.

Parts of the first layer of the SH and RH with distance less than 1 m to steam sootblowers have to be equipped with protective shells for avoiding erosion caused by soot-blowing.

The SH and RH heating surface shall be divided into tube banks, the heights of which shall be limited to as defined in the Data Sheets BI/FB. For convenient access the clear height between subsequent tube banks shall not be) less than 1.2 m with access doors on both sides.

All fittings, spacers and supporting lugs exposed to flue gases shall be made of approved heat and corrosion resistant materials.

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To ensure an effective SH control the final stage shall have a maximum rise in steam temperature at MCR of not more than 75 K for final SH stage.

Each spray water control station for SH and RH shall be fitted with a least 1 control valve, 1non-return valve, 2 isolating valves and 1 hand-operated bypass valve.

Besides all measures taken by the Contractor to avoid unbalanced temperature distribution across the boiler width the Contractor shall provide and install at least 300 thermocouples as temporary provision well distributed on evaporator, SH and RH outlet tubes and assure himself by measurements during commissioning of the plants that at all operating conditions no unbalanced temperatures exceeding max. allowable wall temperature of the single tubes will occur.

1.3.2.2.4 Economizer

The boiler shall be equipped with an economizer which shall be designed to preclude evaporation at any operating condition. Otherwise it must be ensured that the operation of the boiler shall be possible if the HP feed water preheaters are out of operation for a lengthy period. Its arrangement shall be designed to be completely drainable. The water flow shall preferably be upwards.

The heating surface shall be formed by seamless plain tubes which shall be fitted in line.

The economizer shall be divided into banks. The height of the tube banks shall be limited as defined in the Data Sheets B I/FB.

Parts of the first and second layer of tubes with distance less than 1 m to sootblower have to be equipped with protective shells for avoiding of erosion caused by soot-blowing.

All fittings, spacers and supporting lugs of the economizer tubes exposed to the flue gas shall be made of approved corrosion and heat resistant materials.

The feed connections to the drum shall be fitted with thermal sleeves.

1.3.2.2.5 Evaporator with steam drum

The evaporator system shall be designed and arranged to ensure reliable water circulation during all operating conditions.

The gas-tight welded tube walls shall be tied together and stiffened by means of buck stays which shall enclose the furnace and radiant section as well as the convection section.

Low pressure steam shall be introduced in the lower headers to keep the boiler warm and for heating up.

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The design of the buckstays shall consider the expansion of the gas-tight welded tube walls during start-up and shall not result in additional forces.

The downcomers shall not be heated.

The drum shall be of the welded type with a manhole at each end. The wall thickness of the drum shell shall be uniform throughout. It shall be amply sized to ensure adequate steam volume to provide a suitable level control and to preclude the possibility of carrying over of water during any transient mode of plant operation as well as to provide adequate space for mainte-nance work and manual cleaning operation without removing any internal fittings.

The drum shall be fitted with the necessary internals for the uniform distri-bution of the feedwater, with sufficient devices for efficient separation of water from saturated steam.

Access manholes of hinged type shall be provided at each end of the drum heads.

The drum shall be provided with dished ends and with the required nozzles for the water and steam connecting tubes, drains, vents, blowdown, installa-tion of safety valves, controls of pressure, temperature, analyzers and water level. All drum nozzles for valves, fittings and mountings shall be welded to the drums. All internal and external attachments welded to the drum shall be made before final treatment.

The connection between drum and downcomers shall be well distributed over the length of the drum. Entry of downcomers into the drum at the dished ends shall be avoided. The downcomers shall be designed with ample in cross-section-and shall be arranged at an unheated position to avoid any disturbance of the circulation.

The feed connections to the drum shall be fitted with thermal sleeves:

The drum shall be provided with all suitable internal fittings such as:

• removable baffle plates located close to drum internal face, in front of riser pipes.

• centrifugal or cyclic type separators or similar distributed on both sides of the drum and adequately supported .

• steam scrubbers made of perforated plate and located below the saturated steam exhaust pipes .

• feed piping, perforated on its whole length, with adequate supports, extended inside the drum to both sides .

• in case of chemicals injection into the drum for uniform distribution of injected chemicals, adequately supported and securely attached to structural member.

• continuous blow-down tube extended along the whole length of the drum and perforated along its whole length.

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The attachment of drum internals of deflectors to the dram shall be such as to ensure against displacement while the unit is in service, but, except where specifically approved otherwise, they shall not be welded to the internal surfaces of the drums. Bolts and nuts inside to drum shall be fitted with cap nut. The drum internals shall be removable through access manholes.

The drum shall be arranged so that it will not be exposed to combustion gases.

The drum and the appertaining feedwater connections shall be arrange din such a way that during interruption of the feed water supply an emptying of the drum under the lowest water level shall not occur.

13.2.2.6 Supporting tubes and supporting bars

All tube banks located in zones of the gas path in which the gas temperature is higher than 400°C, shall be supported by vertical steam or water cooled supporting tubes. The design of the supporting tubes shall meet the following requirements:

The supporting tubes and the appertaining headers shall be arranged to take over the resulting heat expansion. The temperature of the cooling medium shall be selected in such a way that the temperature difference between the supporting tubes and the temperature of the wall through which the sustained tube bundles penetrate will be a minimum.

The pressure drop, the flow distribution and the materials shall be selected so that a sufficient cooling of all supporting tubes can be assessed during start-up and when the boiler operates at minimum load.

A sufficient number of supporting tubes shall be installed with displaced axis, so that the compartments inside and outside of the supporting tubes can be inspected from the same manhole at the relevant level.

For tube banks located at the direct combustion chamber exit (which is applicable for 11/2 or 1 pass type boilers), the supporting tubes shall form a screen to protect the tube banks against radiation. Suspension of tube coils; on evaporator tubes will not be permitted.

The supporting tubes shall be fully self-drainable.

When suspension bars are required, special care should be given to the selection of materials so that the low temperature corrosion can be minimized.

The individual coils shall be supported by separate support blocks each.

Bifurcation of supporting tubes shall be avoided and the number of bends for the supporting tubes shall be reduced to a minimum.

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13.2.2.7 Headers

The headers shall be of seamless forged manufacture or solid drawn con-struction. The method of connecting the tube elements to headers shall be by means of welding.

All distribution headers shall be adequately sized. To enable visual inspec-tion of the internal space during maintenance periods, conveniently caps on header panel sections shall be provided at sufficient locations to facilitate such internal inspection. The closure of these must be of a permanent type, either strength welded or seal welded. For headers, where this inspection can easily be done by cutting pipes (e.g. overflow pipe header), the inspection caps may be omitted.

The drum on headers shall be provided with shop welded tubular stubs of the set-on type and thicker than the minimum calculated tube thickness. These shall project a sufficient length to ensure that the welding of the tubes will not affect the material of the drum and headers.

1.3.2.2.8 Safety valves, fittings and mountings

All fittings and mountings shall comply with applicable standards and regulations listed

The boiler shall be valved so that start-up and shut-down can be done remotely from the control room. Subsequently, all valves, except the isolating ones which will be shut-off only in case of repair, shall be electro actuated.

It must be possible to operate the motorized valves by hand also.

The valves and actuators installed in the steam generator's steam/water system shall be of an identical pattern and manufacture with those applied for similar piping systems of the power station, which are subject of this Contract.

Double valves on vents and drains and on tapings for instruments and sampling points shall be installed on high pressure and intermediate pres-sure (reheat) pipes.

For the steam generator, the drain configurations shall be as follows:

• superheater and reheater drains shall consist of one shut-off valve and one throttling valve

• vents shall consist of two shut-off valves • evaporator and economizer drains shall consist of two shut-off valves.

These valves shall be arranged so that the upstream valve when closed, has. a spindle and gland which is load-relived and the operation shall be performed with the downstream valve.

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Venting, draining and spray water valve systems shall be combined in groups. Groups of relating drains shall be discharged into common collec-tors.

Pressure test locks, feedwater stop valve and live steam stop valve shall close perfectly tight in both directions (so that it shall be possible to perform the hydraulic test for the boiler and the feed water and steam pipes inde-pendently).

Stop valves or groups of series connected stop valves, in the bodies or between of which condensate may accumulate in closed condition, shall be protected against pressure in excess of the allowable limit.

The steam generator shall be equipped with devices for draining to assure complete drainage of the boiler water/steam system. All drain lines shall have non-dangerous dischargers.

In lines where self-closing blow-down devices are installed, another shut-off device shall also be installed.

Where maintenance at full pressure is required, double isolation with drain in between shall be provided enabling maintenance or repairs- during operation.

The components shall be fixed in approved positions and where applicable shall comply with the requirements of the piping and valve specifications.

The corresponding number of safety valves of approved design and capacity�

shall be fitted to the boiler drums and superheaters and on the hot reheat line.

The safety valves, installed on the boiler drum, superheater outlet, and reheater shall be set to blow in a predetermined sequence. All equipment necessary for gauging the safety valves and for hydraulic test purposes shall be supplied.

Indifferent of the dopted design code, the operation of the HP bypass stations as safety device, shall be mandatory. Set points of HP bypass stations and safety valves in the HP system shall be selected, so that the HP bypass reducing stations will open first. During a trip of the turbine at full load and availability of the HP bypass reducing station, no safety valves on the HP side shall open. One pulse at least shall be transmitted to the control system of the HP bypass station from the saturated steam portion of the boiler.

The set pressure of the reheater safety valves and of the LP bypass stations shall be chosen so that opening of the reheater safety valves will be avoided to the largest possible extent. .

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The safety valves at superheater outlet shall always lift before the safety valve on the drum opens. The superheater safety valves shall have such capacity that the superheater cannot be overheated when also the drum safety valves are blowing. The safety valves shall be of the spring loaded type.

One blow-off station consisting of one throttle and one shut-down valve connected in series with the relating electric actuators shall be installed in the hot reheat line. The capacity of this station shall be determined in accordance with the following requirements:

• operation of the station during start-up until achievement of pressure on which the LP bypass reducing stations enter into operation (if required)

• in case of non-availability of LP bypass stations, a start-up until synchro-nization of the turbine shall be possible.

Silencers of the absorption type or of the combined multiOle expansion! absorption type shall be provided for all safety and electrically operated blow-off valves installed on the steam generator. Start-up valves, safety valves on superheaters and reheaters should be connected to their own silencers.

1.3.2.2.9 Miscellaneous mountings

For cold and hot reheat pips leading to the turbines, pressure test locks shall be installed in the vicinity of the steam generator so that it will not be required during a pressure test of the boiler, to block the supports of the whole piping system.

If the pressure and temperature of the interconnecting steam line to be provided is not sufficient for the sootblowers, fuel atomizing and other necessary purposes, the boiler shall be provided with its own reducing valves in adequate number and size.

An adequate number of thermocouples and fixings shall be provided to measure the superheater outlet header, inside and outside temperature as temperature difference for monitoring of thermal events which may have an influence on headers life time. Drum metal temperature difference measurements shall be supplied.

The corresponding number of blowdown and drain valves for the drum, furnace wall bottom headers, for superheater and headers shall be provided, each set including two valves of an approved bore and type arranged in series.

The necessary vents for venting the economizer, drum and superheaters, reheaters shall be included. Nozzles and isolating valves and test connections for all remote and local pressure indicators shall be supplied.

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1.3.2.2.10 Water level indicators

Two local drum level gauges, showing the full scale complete with lighting fitting shall be included. The electrical energy for these fittings will be taken from the DC supply of the power station.

One gauge shall be fixed so that the water level can be easily seen direct at the boiler drum level. The second bicoloured gauge shall be fitted to enable the water level to be seen from the location of the feedwater control valve.

The gauges shall be fitted with drains, and valves for shutting off and blowing through. Double isolating valves shall be provided.

Two sets of nozzles and isolating valves for water level transmitters shall be provided under the Section B9 (Instrumentation and Control Works). All water level devices shall be provided with independent drum nozzles.

The gauge glass fittings shall be of forged steel and shall be designed so that they can be removed as a complete assembly without shut-down of the boiler.

The water level transmitters shall be connected to a separate pair of branches on the drum for a water level indicator on the main control panel and for the three-element feedwater closed loop control:

• one high and one low level water drum alarm (each independently connected to a pair of branches)

• one independently working low water safety feature for boiler trip • the lower limit of indicating range of the water gauges shall be at least

30 mm above the uppermost pass and at least 30 mm below the minimum water level

• all level gauges shall be provided with a retaining device, so that at bursting of glass the boiler does not need to be shut-down.

1.3.2.2.11 Sampling system

Sampling equipment shall be installed in all places where required for local and remote supervision of operation, for early recognition of disturbances and for the clarification of the causes of damages.

A complete sampling system, including sampling coolers with connections, nozzles, valves, fittings and pipes shall be provided to obtain representative separate samples of live steam condensate, boiler water and feedwater.

The sampling coolers shall be fitted with stainless steel coils and

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stainless steel piping connections up to the take off point.

The position of each sampling point shall ensure representative samples and should be led to one common sampling station or shall be combined in a minimum number of groups (if because of long sampling pipe length the danger of falsification of analysis would exist).

All sample coolers shall be provided with stainless steel trays. The drain of these trays shall be laid to the waste drain system.

The sample coolers shall be designed so that no detrimental consequences will occur on interruption of cooling water supply.

The throttle valves shall be located downstream of the sample coolers in. order to avoid steaming of the sample.

Owing to the elevated temperature of the cooling water, all measurements for which a temperature correction is not possible (e.g. 02 measurement) shall be cooled by a cooling aggregate or separate electric sample coolers shall be provided for each measuring point.

On components where the steam or water flows in two parallel streams, the tapping connections shall be provided in both streams.

Sample coolers of the continuous flow type shall be installed for all points where remote quality recording is required, but at least for,the following points:

• feedwater inlet to economizer

• boiler water (tapped from the continuous blow-down line or from a downcomer)

• live steam (tapped from the main steam line)

• reheat steam (tapped at reheater outlet).

1.3.2.2.12 Integral pipework

The pipes shall be routed in such a manner as to avoid destructive expansion due to temperature changes. The routing of the piping shall allow for complete drainability of the system.

Provision shall be routed in such a manner as to avoid destructive expansion due to temperature changes. The routing of the piping shall allow for complete drainability of the system.

Provision shall be made for heating-up purposes of safety valves and main steam stop valve.

Safety valve escape pipes with all necessary expansion joints, anchors, supports, weather cowls and roof collars shall be provided. Drain pipes to remove condensed steam in the escape pipes shall be led to

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.collector dishes located at a convenient level.

Exhaust lines of flash tanks and safety valves to be extended above the boiler roof level.

In no phase of operation excessive quantities of vapour or water are allowed to be discharged which may spill over equipment or be aspirated by air fans.

Underground drain lines to be of heat resistant material (80°C minimum).

1.3.2.2.13 Heating surface cleaning system

A complete plant for on and off load cleaning of the boiler heating surfaces shall be provided. The cleaning installation shall meet the requirements for coal and diesel fuel oil operation of the steam generator.

Soot blowers

The steam generator shall be equipped with a suitable sootblower system in order to maintain a reliable and economic boiler operation.

Sootblowers shall be located where fouling of heating surfaces may occur and the heat transfer may be affected.

For cleaning the furnace sootblowers of wall cleaning type shall be provided.

In the range of flue gas temperature above 600°C long retractable sootblowers shall be provided on both sides of !he boiler. All tubes and mountings exposed to flue gas shall be of an approved material with efficient corrosion and scale resistance.

All sootblowers shall be located at sufficient distance from the nearest tube row in order to prevent erosion. Additionally, parts of the first tube row less than 1 m distance from sootblowers shall be fitted with protective shells.

Steam for sootblowers shall be taken out of the superheated and reheated steam system. The contractor shall provide a steam reducing station. All steam piping and drains shall be provided according to the specification for pipework.

For regenerative air preheater soot blowers shall be provided on the hot end as well as on the cold end also.

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Sootblowers shall be operated by electrical drives with local pushbuttons as well as a common panel for the whole sootblower system. The preheating of the piping system as well as its drainage and the operation of all sootblowers in a suitable sequence shall be actuated by a master pushbutton from this panel. Failure in the operation shall be indicated by alarm lights of the panel and a common alarm signal will be conducted to the unit control room.

Two cooling and sealing air fans (on stand-by) shall avoid the, tendency for flue gas corrosion.

All retractable type sootblowers shall be adequately supported and be provided with lateral protection against accidentally knocking as well as to provide correct guidance during insertion procedures. All sootblowers shall be suitably guarded to prevent personnel coming into contact with moving parts or hot surfaces.

Accommodation for test pressure gauges shall be provided in the medium supply pipes and/or at the blower lance to check the blowing steam pressure. The pressure shall be adjusted as necessary to obtain the optimum cleaning conditions.

The numbers of sootblowing cycles shall be three per day as a maximum. Sootblowing shall be possible at any load of the steam generator.

Adequate lubrication of the sootblowers shall be provided.

The arrangement of sootblowers and platforms shall give no interference and shall allow a free walking height ofat least 2.1 m.

Washing installations for heating surfaces

The selection and supply of equipment for washing of the steam generator shall meet the following requirements:

Equipment and washing process shall be chosen with regard to a minimum demand of water.

Washing of convective heating surfaces and furnace shall be made by hand by using hoses. All relevant hoses, washing water utility stations at various boiler platforms, connecting pipes and/or pumps (if required) from the water supply source to the utility stations and drainage ducts shall be provided under this Contract.

For the regenerative air preheaters a fixed installed washing system shall be provided which must be suited to wash one of the air preheaters when the unit is in operation.

Regenerative air heaters shall be supplied and designed to permit off-

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load washing with process water. The system shall include all supply pipes, pumps dosing system, discharge pipes, dust separator complete with internals, discharge ducts and pumps (if required) from the dust separator.

Drainage pipes of air heaters washing system shall be provided with double shut-off valves and drain valves in between, in order o exclude the intrusion of water into the dry ash removal system. The same shall apply also for other drainage points where dry ash and washing water will be discharged into the same piping system.


The steam generator shall be equipped with a complete coal grinding and firing system and an ignition and back-up firing system based on diesel fuel, comprising the following main items:

• coal bunkers

• coal feeders

• coal mills

• combined coal/oil low-NOx-burners

• primary air fans (P A fans)

• diesel fuel oil systems

• PC burner pipes

The PC firing as the principal firing for the boiler shall be designed for direct firing. It shall be capable to cover the specified boiler turn-down range. The MCR load point and partial loads of 30% MCR and greater shall be achievable without the aid of the ignition and backup firing, but taking into account the specified fuel range. Depending on the coal quality, in the minimum load range it shall be permissible to operate the ignition, back-up and support firing system.

The number, type and arrangement of the PC burners shall be decided by the Contractor. It shall be guaranteed that the prescribed design data and operational requirements are met completely.

Of particular importance is that the statutory emission standards for nitrogen oxides will be met.

Also the isolation arrangements shall be of low wear design and require versionly no maintenance.

The burners shall be so assigned to the mills that if one or more of the mills is switched off or fails, asymmetric fireside temperatures wiIl be avoided.

Shut-down of one or more complete burner levels shall also serve the purpose of achieving the required minimum load. Cooling measures for

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the burners which are not in operation have to be foreseen for avoiding damages caused by furnace heat.

It is essential that the Plant shall be dust tight in every respect and all bearings and working parts shall have dust proof housings.

For monitoring the flames of the PC firing system, flame detectors shall be provided. Which in the event of the failure of its associated burner group will not be effected in its action by extraneous light or spurious radiation from the furnace. The offer shall be accompanied by a detailed description and drawing of the combined burners and a reference list.

The ignition and backup firing system shall be designed for the fuels and load range as laid down in the prescribed design data, without consideration of the PC firing equipment. The number and arrangement of the combined ignition and backup burners shall meet the requirements of the PC burners.

The pulverizing and firing system shall be adaptable to varying fuel qualities in such a way that on the one hand a stable firing of worse fuel sorts is possible and on the other hand no slagging of the furnace will occur when burning higher qualities of fuel.

Each ignition and backup burner shall be fitted with a pure gas-electric ignition device and gas bottle station, its own flame detector, a combustion air control damper and all other auxiliaries connections and slop tank shall be provided.

Piping to the ignition and backup burners shall start at the inlet of the isolation valve outside of the boiler area, be routed to all burners, and shall contain all safety relevant equipment, fittings and burners valves and accessories. For each burner, two quick acting safety shut-off valves with intermediate drains to the slop oil tank shall be provided.

Explosion protection of the electrical equipment belonging to the coal grinding and firing system shall be in compliance with the requirements of the NFP A code or recommendations or other similar standards.

1.3.3.1 Coal bunker

Each pulverizer has to be fed from one coal bunker and one feeder.

The bunkers shall provide the necessary counter pressure by means of a minimum coal level against the pressure in the coal mills.

The design of the bunkers shall guarantee a controlled, continuous and undisturbed feeding of the mills. This should be achieved by giving a due consideration to the properties of the stored and selected of a suitable form and suitable outlet openings.

Each boiler unit has 4 coal bunkers. The bunkers shall be provided with a total reserve corresponding to a minimum of 16 hours of operating at

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MCR as "active content". The "active content" of the bunkers shall be as large as feasible, reducing the stagnant mass to a minimum.

The bunkers shall be properly integrated with the boiler steel structure, presenting an overall neat appearance. For this reason, they should preferably be of rectangular or square form in plain view with pyramidal hoppers.

The following recommendations should be followed for the section of the shape of bunkers:

• steep sides of hoppers, with a minimum inclination of 75° to the hori-zontal opposite sides having, if possible, a different angle of inclination,

• bunker discharge zones with large outlet openings, minimum dimension of 1.0 m

• no additional constructions between outlet openings and feeders (maximum length of 2.00 m)

• round off with a minimum r = 600 mm at bunker edge.

The geometry of bunkers shall be satisfy the mass flow requirements, taking into account the following:

• kind/type of stored coal

• properties of wall linings

• number, shape and size of outlets and auxiliary outlet equipment

• prevent coal dust emission.

All measures which are necessary to reduce the effects of funneling, arching and segregation of the stored coal shall be duly considered.

Carbon steel of sufficient abrasive resistance and good welding properties shall be used for bunkers plates. Stiffeners and all supporting steel shall he conform to the standard specification.

The bunkers shall be designed with unlined inside surface by considering no plugging and smooth coal discharge operation. '

The bunkers shall be designed to meet all applicable loads.

The bunkers shall have sufficient rigidity in order t 0 prevent distortion during erection and to reduce bulging effects due to the stored coal. A suitable allowance for abrasion and corrosion shall be used in specifying the plate thickness.

It shall specify all loads required for the design of foundation and of adjacent buildings. Design interfaces shall be established as soon as the structural concept is established.

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For the determination of the auxiliary outlet equipment, such as shut-of rods, assisting equipment for coal flow-out, conveying elements, etc. increased reliability margins shall be considered.

The bunkers shall be of welded steel construction.

Due attention shall be given during erection to the following items:

• interfaces with the construction of foundation

• interfaces with the construction of adjacent buildings and structures

• sequence of erection (welding)

• erection tolerance.

Bunker emptying facilities are to be provided. These shall consist of:

• A permanent mild steel chute extending form underneath each feeder, through the operating floor to a position just above the mill cranage runway beams. The cute shall be positioned so that coal in the feeder will reach it before reaching the discharge opening in the mill.

• A needle weir at the entry of each permanent chute. This will be in the close position for normal operation of the feeder. A blanking plate shall also be provided at the end of the� chute.

• One motor operated slide gate valve shall be provided at each bunker outlet.

• A temporary chute, for attachment to the permanent chute and extending from the permanent chute to a position in the mill aisle convenient for direct discharge onto a lorry. The chute shall be made from mild steel except for the least 2 m of the chute which shall be of a reinforced rubber to facilitate even distribution on the lorry.

It is envisaged that only one bunker will be emptied at a time and therefore only one temporary chute per unit is required.

Gallery access for coupling the temporary chute shall be provided.

The bunkers shall be provided with probes to actuate automatically a tripper conveyor and belt trip with indication in the coal handling control panel and also a high level alarm.

Each bunker shall also be provided with low level detectors to operate a position on the centralized control boiler annunciator and operate warning lights and alarms in the coal handling panel.

Suitable coal anti-bridging devices shall be provided such as vibrators.

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For the chutes from the bunker to the pulverizers a pneumatic deblocking system shall be provided. In addition the chutes shall be provided with breakaways (gradual enlargement to relieve lateral pressure and pipe friction).

The bunkers shall be provided with an C02 fire fighting system.

1.3.3.2 Coal feeders

The raw coal is to be fed even distributed to the centre of the mills by means of encapsulated plate conveyors. The coal feeders shall be designed dustproof and pressure-tight (gauge pressure of 0.5 bar). The coal feeders are to be designed with enough margin in capacity compared with the coal mills.

All sides of the casings of the plate conveyors - including the shaft ducts must be absolutely tight against dust escape. The front and side walls, dis-charge box must be at least 4 mm thick. The scraper floor must have a thickness of 8 mm or more.

It is to be ensured by means of the suitable choices of coal bed thickness, conveyor speed and paddle shaft speed that coal feeding is effected continuously in every load range. The .coal feeders have to be equipped with an coal bed thickness indicator.

The plate conveyor is to be of a solid and wear-resistant construction so that it can be operated throughout its entire service life without constant repair work being necessary.

In order to prevent corrosion to the roller chains of the coal feeders, an air seal supply with gate valve is to be connected at the outlet of every coal feeder. Pipes and valves belong to the scope of supply of the Contractor.

Steplessly variable drives with remote adjustment are to be provided as variable speed transmissions.

The coal damper, coal fall shaft in the feeder discharge section and the bunker passage to the feeders are to be lined with stainless steel.

In addition, the mill feeders are to be equipped with needle weirs, height levelling frames (stainless steel) coal bed thickness controllers, pendulum plate, tension station and automatic oil Iubrication equipment of for the conveyor, paddle and scraper shafts, Belt or chain cleaning device, one inspection door (0.5 m x 0.5 m) above coal feeder and at front and rear side, chutes between feeders and mills, complete scraper equipment and complete air seal equipment. \

Dumping of coal from the feeder to the mills shall be done vertically or

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nearly vertically.

1.3.3.3 Coal mills/pulverizers

The pulverizers and the firing plant shall match the boiler plant overall layout and shall be designed so that all operation requirements including start-up and shut-down, also transient at turbine trip, emergency boiler shut down, or failure in the internal power supply can be covered safely and without damage.

The coal pulverizer shall be suitable for pressurized operation in conjunction with primary air fan.

The pulverizers shall be equipped with adjustable classifier system (separator).

The system shall operate as a continuous process and, within the specified design limitations, the coal feeding shall be varied as rapidly and as widely as required by the combustion process.

It shall be possible to be operated the pulverizers and firing plant stable and safely between 30% and 100% boiler MCR.

At all partial load conditions it shall be assured that each burner has the same and controlled fuel/air ratio.

The coal supply, pulverizing and burning system shall be arranged as independent path from the bunkers, coal feeders, pulverizers, pipe work, to the burners.

The pulverized coal system shall be supplied completely with accessories as specified and as required for a complete unit and to secure safe, reliable and efficient operation.

The pulverizer shall be of Low speed Horizontal Ball mill (2 inlet 2 outlet) type of proven design and of pressurized operation type. Coal mill shall be designed by considering Coal Hard Grove Grindibility index (HGI) 75.

The feeding of the coal into the pulverizer shall be centric through the classifiers. Each pulverizer has to be equipped with an automatic operating steam smothering system.

Manhole covers and inspection hole covers at pulverizers and fans shall be designed so that absolute dust tightness can be guaranteed. The inner mill casing has to be manufactured without dead comers.

The pulverizer gear shall be easily exchangeable in such a way that during necessary gear repair an exchange of the gear is possible without dismantling important parts of the pulverizer casing.

All pulverizers shall be equipped with adequate and insert gas protection fire-fighting system by steam.

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If pulverizers and feeders are stopped by an electric failure, starting-up again shall be possible without previous cleaning.

The mills shall be designed in such a way that they can easily rearmoured within a short time on the spot and that all other repairs can also be executed.

It shall be possible to isolate the mills from the hot air/gas ducts and from the dust ducts in such a way that the boiler operation will not ~e disturbed when isolating one mill, and that maintenance work such as rearmouring has not to be done under hard conditions. Doors of the pulverizers shall be provided with hinges and quick acting opening dosing facilities.

Pulverizer maintenance and repair shall be possible during plant operation in a quick and safe manner.

Boiler MCR shall be possible also during failure of one pulverizer and the related burners shall be cooled sufficiently.

The main criteria for the pulverizer design has to be

• 3 mills at design coal for MCR

• 4 mills at worst coal for MCR.

These operation conditions shall be possible without fuel oil firing in service.

Particular guarantees shall be given for all pulverizer parts subject to wear and erosion (the guarantee period is based upon stated coal quantities).

All parts subject to wear and tear shall be so designed that an exchange of worn-out parts shall be possible (easy access), even while boiler is in operation.

After the guarantee period of pulverizer parts, subject to wear and erosion, the pulverizer capacity throughout may decrease by a maximum of 10%.

Suitable measures shall be taken to prevent, under all operating conditions, each part of the mill being endangered by over temperature.

The gear shall be of the totally enclosed type.

Each mill shall be provided with its own lubrication oil system, including oil cooler, oil tank with heater, duplex filter and double capacity oil pumps.

Sealing air connections and seals shall be provided on the mill journals and on the mill casing in order to protect the bearings against the entry of dust.

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1.3.3.4 Pulverized coal burners (PC burners)

Type, number, arrangement and size of the PC burner shall be selected by the Contractor.

The pulverized fuel burners shall be designed in such a way that a good mixing of dust coal and combustion air as well as a safe ignition of the dust coal will be achieved.

The arrangement and alignment of the burners shall ensure an even tem-perature profile of the flue gas leaving the combustion chamber.

The PC burners shall be selected such to comply with the properties of the coal and shall match the pulverizing system. It must be adequate for an optimum combustion with due consideration to the furnace dimensions in order to keep the NOx emission to a minimum and to avoid excessive fouling.

Pulverized coal pipes and burners as well as burner installation shall be arranged to guarantee easy dismantling of the burners and other wear parts. Erection and dismantling devices shall be provided by the Contractor.

It has to be shown by reference plants or in a flow test plant that a perfect flame distribution and combustion quality for the total coal range and all loads can be guaranteed. Sufficient possibilities of air regulation during operation are to be provided.

Each burner shall be provided with its own lighter and flame scanner. The burners shall be robust and shall stand long operation periods. Adequate measures shall be taken to protect coal burners which are not in operation from being damaged by radiation of heat coming from the furnace.

Each coal burner has to be equipped with thermocouples to measure the burner mouth temperature if burners are out of service during boiler option.

Relative movements between coal burners and furnace walls shall be compensated without that excessive forces act upon the burners and without that false air penetrates perceptibly, into the furnace.

The supporting steel structure of the burners and the appropriate coal ducts shall be designed so as to serve simultaneously for the suspension of lifting devices required for assembling and dismantling of burners and ducts.

Selection of type of coal burner shall be made also under consideration that simultaneous operation of the steam generator with coal and with diesel fuel oil will be possible.

1.3.3.5 Distribution of pulverized coal

Pulverized coal pipes from the mills to the burners shall be arranged in view of maximum symmetry to achieve even distribution to all burners.

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The individual pulverized coal pipes behind the distributors shall be pro-vided with shut-off devices which upon shut-down of one mill shall be closed for avoiding the recirculation of hot flue gases.

Each coal pipe has to be equipped with air sealed test opening (approxi-mately 500 mm in diameter) to extract pulverized coal for measurement of grain size and coal distribution. Provisions for galleries in this area are to be made.

The dust coal pipes from mills to burners shall be as short as possible and arranged as straight as possible.

Changes of mills load shall not cause any disturbance of the gas and coal dust flow in the pipes.

Pulverized coal pipes shall be from steel piping or sheet with sufficient wall thickness and all necessary protection measures against wear and tear. Each PC pipe has to be equipped with two coal extraction studs for sampling. The extraction studs have to be equipped with an air sealing device for preventing the PC leaving the PC pipes during sampling.

1.3.3.6 Primary air fan (PA fan)

To boost the pressure of the primary air, two radial fans with motors are to be provided to extract cold air from behind the FD fans. Both of the radial fans are to be designed for a mass how of at least 10% more than the MCR primary air mass flow.

The requirements for noise protection stated in Section B06 and B07 shall apply.

Control shall be effected via adjustable vane inlet controller(s).

Fan vanes shall be made in welded construction. The drive shaft shall be dimensioned to withstand the critical speed by far.

Impeller wheel and shaft must be statically and dynamically balanced. Bearing, coupling, seal and fan with spiral housing including access� opening in the housing are to be split; the dismantling of the impeller wheel must be possible without great difficulty; the motor, bearing and fans are to be set up so as to be vibration-dampened; there are to be suction and discharge connections, vibration damper and all necessary measuring equipment, etc.

Furthermore, there are to be suction and discharge-side silencers with insulation casing and transition pieces.

Scaling air fans

The delivery head should be sufficient so that no pulverized coal can leave the pulverized coal area into bearings, atmosphere, etc.

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1.3.3.7 Inerting system for pulverizers and coal pipes

Special care is to be taken to avoid explosions inside the pulverizers and coal pipes, especially when burning coal with a self-ignition temperature of 220°C and high volatile matter.

The provision of the plant with an inerting system will be mandatory. The offer shall consider an inerting system based on nitrogen, CO2, inertisation with steam or flue gas (according to the manufacturer's standard and for experience).

1.3.3.8 Start-up and backup firing system operating on diesel fuel oil

The diesel oil system will be used for boiler start-up and backup firing up to 35% MCR boiler load.

The diesel oil system to be in accordance with TRD 411 or other similar standards shall be completely up to the burners comprising following main items:

•diesel oil burners with burner stations in groups, integrated in the

centre of the PC burners with oil return system .

• filtering, pumping station, tank with unloading station and integral piping for diesel oil, including control valves

• flow measurement devices for supply and return pipes motor driven

main shut-off valve arranged at the end of the oil supply ~ pipes

(before distribution to the burner stations.

Type, number, arrangement and size of combined coal - diesel oil burners

shall be selected in such a way as to cope with the above requirements.

Each combined coal diesel oil burner has to be equipped with ignition and cooling air supply, high energy spark plug ignitor and all necessary valves, dampers and flame detectors.

Openings for burner lance, flame detectors, ignition Iance and inspection peep holes are to be provided.

Each burner has to be equipped with an adjustable airswirl vane assembly for optimizing the flame shape.

Burner shall not be subject to any deterioration by radiant heat when out of operation. Therefore oil guns and ignition equipment shall be pneumatically retracted in cooling position. A separate cooling air system has to be arranged for cooling the burners, which are out of operation.

Flame detection system (IR/UV receiver) shall be of the self-checking design. Start-up and shutdown shall be realized by a sequence programme.

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Each valve combination for diesel fuel oil has to be carried out as duplex block and bleed valve set.

The fuel oil strainers shall be of the cage type with a maximum gap width of 0.5 mm on the suction side and 0.08 on the pressure side.

The strainer assembly shall include integral flow switching gate valves, external valve position indicators, differential pressure gauge, steam tracing and valves for drains and vents.

The oil pumps shall be of the rotary screwed type. The horizontal pump units shall be coupled directly to the driving motor. Each pump shall be fitted with a pressure relief valve preventing over-pressure in the pump casing. Pump and motor shall be mounted on a common base plate.

Spindles of the pumps shall be approved material nitrided and ground. The design of the pumps shall take into account the increased oil temperature in the casing.

The pump casings shall be at least of cast steel. Cast iron is not acceptable.

The pumps must be designed and suitable both for continuous or intermittent operation. They must also be ready for immediate service even after a prolonged period of standstill, without any special measures being necessary.

Suitable cleaning and drain piping of the systems to the slop-tanks have to be supplied.

The arrangement of the whole equipment shall allow access to all valves and instruments.

Integral piping for diesel oil, cooling air and compressed air shall comply, with the requirements of this specification.

Besides the remote control system it shall be possible to operate the burner from local box near the burner with minimum employment of the remote control system. The change-over from remote control to local control shall be done by key switch for each burner located on the control room panel.

The remote control system and the interlocking system as well as the closed loop control shall be provided under Chapter B9 in these Tender Documents. Therefore the firing system also shall meet the requirements of Chapter B9 (Instrumentation and Control Works).

1.3.3.9 Diesel oil storage tank and unloading station

All the equipment for the diesel fuel oil system shall be of the outdoor design. Scope of supply/ installation shall include but not limited to the following: • One (01) diesel oil storage tank (tank capacity 2000 m3); • Diesel oil unloading station [Two (02) diesel oil unloading pumps including

valves, pipings, filters and others as per requirement]; • Interconnection with the existing diesel oil system.

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Basically the tanks shall be designed in accordance with the requirements of API Standard 650 or an approved equivalent standard. If the specification contains requirements beyond the requirements of the above standard, the requirements of the specification shall have priority.

The tank roofs shall be of the self-supported cone roof type.

To prevent any damage to the tanks by storms, they shall be reliably stiffened. If stiffening rings will be necessary, they shall be arranged inside of the tanks.

The specific gravity of all tank contents shall be considered with 1,000 kg/m3.

Corrosion allowances shall not be provided for the tanks.

The tank bottom shall be pitched downwards conically to the outside with a slope of at least 1 %.

Around the inside tank perimeter two drainage sumps shall be provided. Each sump shall be equipped with a 50 mm diameter drain pipe connected to the shell double flange nozzle. A shut-off valve with a blind flange shall be provided outside the tank.

All flanges at the tank shall meet the requirements of the piping systems set out in Section B06 General Technical Requirements, Mechanical Equipment. The flanges shall be of the welding-neck type.

All connection and spare nozzles shall be provided with flanges inside and outside of the tank. All spare nozzles have to equipped with blind flanges outside the tank.

The fill nozzle is to be designed as a roof unit. A bend pointing on to the� tank wall is to be flanged on to the inside of the tank so that incoming oil ' flows tangentially to the tank wall. Care must be taken to ensue that the bend is

located with about half its effective section above the highest liquid level. A baffle plate is to be provided at the tank wall.

All other nozzles - with the exception of ventilation and sounding hatch and the return nozzle of the heavy fuel oil tank - are to be arrange din the lower shell course.

Shell manholes are to be equipped with hinges (davits). A safety device prevention unintentional closure of the cover is also to be provided. The clear diameter of all manholes (shell and roof) shall be 600 mm at least.

A shell spiral staircase shall be furnished from grade to the top of the tank. An intermediate platform is to be arranged at half the tank height.

Two roof vents shall be provided and each shall be designed for 100% capacity to pass air so that at the maximum possible flow rate of the oil, either entering or leaving the tank, excessive positive or negative pressure will not be

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developed. The vent intake shall be protected by a screen with a mesh width of not more than 5 mm. The clear screen area shall be at least 125% of the vent nozzle area.

A 100 mm high kick-plate, tightly welded around the entire tank perimeter and acting as a gutter is to be arranged on the tank. top edge. For each tank at least two rain downpipes, connected to the kick-plate and provided at their bottom ends with a 45° bend, are to be provided.

Each tank. is to be equipped with a device for local and remote level indication. All level indicators at tanks shall have scales which indicates meters and millimeters. Corresponding volumetric tables must be made available also. This device shall be equipped with at least three adjustable limit contacts to initiate alarms or signals at given levels (low, high, maximum).

Each tank shall be provided with an overfilling protection device (level switch) which shall respond when the maximum permissible level is exceeded by initiating an alarm and switch off the filling� pump of the oil truck.

The maximum limit contact of the level indicator shall also protect the tank from overfilling by initiating an alarm.

The surface preparation, interior and exterior coating application, shall be done in accordance with the requirements set out in Chapter BO "General Technical Specification". Inside painting shall be applied only to the tank bottom and one meter height of the shell above bottom.

In the dimensioning of all attachments on the outside of the tank, such as sockets, manholes, measuring instruments, etc., allowance shall be made for an insulation layer with a thickness of approximately 100 mm. The insulation shall meet the requirements set out in Section B06 (General Technical Requirements).

A pipe extending 2 - 3 m into the tank is to be flanged inside on to the bottom discharge connection piece. The end of the pipe is to be provided with a bend. The bend shall extend into a pour-in bowl, the upper end of which shall terminate at the level of the sounding plate. The clear inlet area. of the pour-in bowl shall be at least 2 times the outlet nozzle area.

1.3.3.10 Slop oil tank

The slop oil tank may be supplied wither as rectangular tank or as a horizontal cylindrical tank. All necessary connections, manholes, drains and ventilation systems are to be provided where required and made easily accessible.

The tank is also to be equipped with a local contents indicator having a sensor arrangement to issue an alarm when the tank is full. Also to be provided is a further level switch arranged to sever as dry-running protection for the pump and to annunciate when the tank is empty.

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1.3.3.11 Filters

For the diesel oil pump group, one duplex filter shall be provided on the suction side.

The duplex filter shall be equipped with a change-over device which allows change-over under full load conditions without operating trouble

Each slop oil pump shall be protected by a single filter arranged in the suction line. Each filter shall mainly consist of the filter bowl with cover and removable filter insert.

All the filters shall be fitted with a differential pressure indicator equipped with transmitters for electrical remote indication and alarm.

Filter covers are to be fastened by hinged bolts.

Filter bowls are to be equipped with stripping connections and valve.

Consideration is to be given to maximization of useful screen area to keep initial pressure drop as low as possible

The switching point of the differential pressure gauge shall be freely settable

Filter casings must be at least of cast steel. Cast iron is not acceptable

1.3.3.12 Pipelines, foam pourer

The pipelines shall be designed according to the requirements of Section B06 (General Technical Requirements).

A pipe emptying system shall be provided for the entire pipework system, so that pipes which are out of use for longer periods can be emptied and do not require continuous heating.

Each foam pourer is to be allocated a foam generator which shall be fitted in the immediate vicinity of the foam pourer.

The foam generators and foam pourers shall be made of process water resistant and heat resistant materials.

The foam system for the oil tank shall be capable for foaming the complete internal surface of oil.

Components made of plastic, plastic coatings, rubber or other materials which in the event of fire, as a result of the effect of heat could prejudice the operation of the foam generators or the foam pourers must not be used.

The pipes and valves of the foam system shall be made of corrosion resis-tant and heat resistant materials. Stainless steel or approved equivalent

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materials shall be used. The nominal pressure of the foam system should with adequate reliability be above the maximum possible operating pres-sure.

1.3.3.13 Electrical, control and monitoring equipment

The diesel oil pumps sl1all be controllable from the auxiliary panel in the central control room. Indication of operating conditions, must, however, also be available at the local control board.

Oil levels of tanks as well as all hazard, fault and monitoring information from tanks, filters, pumps, etc., must be clearly arranged and recognizable in the central control room.

The foam system shall work automatically by means of push button control in the central control room.

1.3.4 Auxiliary steam boiler (if required)

Existing 2 x 125 MW units have 1 (one) 10 ton/ hr capacity auxiliary steam boiler. If these capacity is not enough for the proposed 250 + 10% MW unit, then 1 (one) auxiliary steam boiler is required.

The auxiliary steam boiler fired with diesel fuel oil has to be provided if necessary to supply steam to the steam turbine unit during the start-up period. For an outdoor installation a respective weatherproof implementa-tion has to be foreseen.

The number, type, capacity, steam parameters and arrangement of the auxiliary steam boiler shall be decided by the Contractor.

Demineralized water will be used as boiler make-up water which is supplied from the demineralization water plant.

The boiler used as the auxiliary boiler has the characteristics of frequent start-ups, large changes of load, quick start-up, long periods between maintenance, start-up at any time and operating reliability; being a packaged completely assembled and then dispatched to site.

Because of characteristic difference between start-up boiler and normal boiler, the water of this boiler can be drained completely and a nitrogen blanketing protection connection shall be provided.

The plat form and gallery of boiler shall possess enough strength and stiffness shall be proved at operation, monitoring or maintenance locations.

The boiler shall be provided with the necessary observation ports, manhole for maintenance and explosion vents.

The drum shall be provided with safety valve, vent valve, exhaust piping

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and a motor driven valve, and a silencer shall be provided at the outlet header of the superheater.

Connections for drum water level and furnace pressure measuring shall be provided. Local instruments and remote instruments (in the control room) shall be used for drum water level measuring, and the pressure, temperature and flow rate shall have indications in the control room.

The boiler shall be provided with one set of forced draft fans, feedwater and oil pumps. The steam pipe lines of the auxiliary boilers shall be connected together and also with the extraction of the steam turbines. So that it is possible, while the auxiliary boilers are shutdown, to start-up the second steam turbine by the first, which is already in operation.

1.3.5 Inside cleaning of boiler pressure parts

After erection of each boiler the manufacturer shall perform boiling out and blowing out as a protection measure. If necessary, the boilers shall be passivated after this procedure. No acid cleaning measure is required but the coal fired boilers themselves must be designed and fabricated in such a way that an acid cleaning process can be carried out if required by the Purchaser.

If it will be found out after boiler erection that the inside tube and header surfaces "are rusty and dirty, acid cleaning of boiler and all other equipment will be carried out by the supplier without any costs for the Purchaser.

The criteria for above decision are as follows:

• drum and headers are to be visually clean without any corrosion

• cut tube samples may not have more than 0.11 mm corrosion layer or 15 mg/cm2 corrosion layer

• recommended steam quality for starting up shall be reached within 2 - 3

days.

At least three months before the date fixed for the internal cleaning, the boiler manufacturer shall submit to the approval of the Purchaser a complete and detailed specification of the procedures that will be carried out giving all sequential events and chemical analysis required.

The contract supply shall include for the boiler all necessary connections, valves, fittings, etc. required for acid cleaning which might be required after a certain period of operation.

The temporary blow-off pipe and blow-off valve should have the same size as the main steam pipe and main steam valve.

For boiler conservation before commissioning the Contractor shall provide all necessary equipment, material and consumables to maintain the boiler parts in a non-corrosive state in accordance with the offered procedure.

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BPDB, Barapukuria Power Plant Minimum requirements

Section B1: Steam Generator

Performance and Design Criteria Unit Data

1. Thermodynamic Data

Steam generator

Max continuous rating (MCR) % 104 of turbine MCR flow

Steam pressure (abs.) at HP superheater outlet bar 145

Steam temperature at HP supertleater outlet 0C 535

Steam temperature at reheater outlet 0C 535

Constant steam temperature forth. HP superheaters of 535 0C MCR 60 -100

Constant temperature for the reheater of 5350C MCR 70-100

Minimum load far continuous operation without back-Up firing MCR 30

Max operating pressure at flue gas side of boiler membrane mbar + 70

walls/ducts

Load range firing with diesel fuel oil MCR 0-35

Feedwater temperature at economizer inlet 0C approx.. 207

Reheater (RH) Data at MCR

Steam mass flaw at Inlet kg/s cold and hot reheat steam pa

rammers shall correspond with the relevant data resulting from the

heat flow diagram of the turbine model selected

$team pressure (abs.) It RH inlet bar

Steam temperature at RH Inlet 0C

Feedwater quality

Feedwater quality in line wtth “VGB Directives for boiler, boiler water and steam from water tube boiler Operating at pressure of 68 bar and up (Iatest edition)

Chemical mode of Operatiion1alkaline as per VGB Directive

pH-Value 8.0 - 8.5

Flue Gas

• flue gas temperature It regenerative preheater outlet 0C 150

• max. allowable flue gas temperature at ESP inlet for 10 min.

0C 350

B1/FB1

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2. Performance in Service

Intended operating regime

• operating hours per year n/a 8500

• total cold starts per year - 10 • cold starts (after 48 h shutdown) per year - 30 • warm restarts (a1tsr 8 h shutdown) per year - 100

• hot restarts (after 2 h shutdown) per year - 20

Rate of load change From 50 – 100% load (referred to MCR) % MCR/ min ±6 From 30 - 1 00% load (referred to MCR) % MCR/ min ±4 Start-up times

Planned start-up times from cold condition up to 450 0C

and 70 bar

h 4

In order to achieve this start-up time and very short start-up times for warm and hat restarts, the shortest possible start-uptimes for the steam generator shill be stated in the corresponding data sheet. Moreover the corresponding start-up curves shall be submitted, in which also the relevant boundary conditions shall be stated.

For rolling the turbine generator. initially minimum steam conditions as follows shall be assumed:

Cold start from OC/bar up to OC/bar

50/1.0 450/70

min

Warm start from OC/bar to OC/bar

300/50 500/100

min

Hot Start from OC/bar to OC/bar

450/120 535/145

min

Precise start-up conditions will be established after ordering the steam turbine generator jointly by the boiler and the steam turbine generator suppliers, with the permissible gradients of the steam turbine generator being taken into account by the contractor in his own start-up curves.

B1/FB2

241

BPDB, Barapukuria Power Plant

Minimum requirements Section B1: Steam Generator


3. Design Construction Data Boiler drum The steam space loading shall be smaller than m3/ h 400 The elliptical manholes at each end of the drum not less than . mm 380 x 425 Maximum saturated steam velocity In connecting tubes to SH m/s 12 Economizer Max. height of heating surface tube banks m 1.8

Min. clearance between two heating surface tube banks with access possibility and/or where sootblowers are installed

m 1.2

Type of tubes used - plain tubes Type arrangement - in-line Transverse pitch not less than mm 100 Longitudinal pitch not less than mm 80 Add-on reserve heating surface % 10 Arrangement of access doors - on both sides Support tubes/support tube granting - Directly down Preferred connection. stream of evaporator Pitch in first platen heating surface

• transverse pitch not less than mm 800 • longitudinal pitch not Jess than mm 60

Superheater (SH) Max. height of heating surface tube banks m 1.8 Minimum clearance betw8en two tube banks if access possibility provided and/or where sootblowers Installed

m 1.2

Design of super heater -

2 pass 3 stages

Arrangement of the connection pipelines between the SH stages - crosswise Number of required attemperators between superheater stages ll and III

pieces 2

Plane tube arrangement - inline

Transverse pitch SH l/ll not less than mm 100/200

longitudinal pitch SH l/ll not less than mm 55 Arrangement of across doors

- on both sides

Add-on reserve heating Surface as margin % 10 Max. permissible steam side temperature rise In the final super heater

0C 75

B1/FB3

242




Reheater (RH) Max. height of heating surface tube banks m 1.8 Minimum clearance between two tube banks where an access possibility is provided and! Dr where sootblowers are installed

m 1.8

Design of reheater - 2-pass Arrangement of connection pipelines between the RH stages crosswise Number of necessary attemperators between reheater stages I and II

pieces 2

Tube arrangement - in line Transverse pitch RH I not less than mm 100 Longitudinal pitch RH I not less than mm 70 Transverse pitch RH ll not less than mm 400 Longitudinal pitch RH II not less than mm 70 Add-on reserve heating surface % 10 Arrangement of access doors on both sides .

The attemperator spray water quality corresponds to that of the feedwater

Firing system, fuels PC direct firing

principle gas-side vacuum

Firing operated with Main fuel

high volatile

bituminous coal The fuel. specification shall be adapted for the design of the boiler and its associated equipment according to Annex

Note:

1. The boiler shall attain its MCR when firingng the coal within the band with specified at any of the local ambient conditions.

2. Optimizing of boiler design Shall be based on the guaran-tee coal.

Characteristics of coal ash according to Annex Fuel for ignition of coal burners

• for cold start-up conditions • for warm start-up conditions and back-up firing

.diesel fuel oil

..net calorific value MJ/kg 42

Load range of ignition end back-up firing of MCR % 0- 35

B1/FB4

243




Excess air

Maximum excess air in furnace. for coal firing (guarantee coal) between 60 % and 100 % MCR.

% 20

coal bunkers

Number of coal bunkers - 4

Design of the bunker cells and supporting structure - steel structure

Net storage capacity of bunker shall correspond to the coal demand for operation of

operation hours

24 at MCR

Coal feeder

Range of control, minimum 1:5

Resistant up to pressure of bar 3.5

Coal preparation and burning equipment

Number of pulverizes an which the boiler has to achieve Its MCR with any of the coals fired

n-1

Minimum number of pulverizes In operation at minimum load of the boiler of 30%.

2

Pulverizers

Minimum interval between two scheduled Overhauls of the mills

hours 8,000

Design margins of each pulverize:

addition of wear- to-tear % 10

addition for control margin % 5

Distribution of pulverized coal

Minimum admissible velocity at pulverized coal/air mixture m/s 18

Pulverized coal burners

The capacity of an burners shall be such that the boiler MCR can be malntained with one burner out of operation (n-1)

� -

Primary air fan

Safety margins for design

2 fans operating in parallel:

delivery head % 110

capacity % 121 B1/FB5

244




or 1 single fan:

• capacity %MCR 60

Other data:

• temperature of regenerative air preheater exit 0C design temperature + 5O 0K

Type . radial

Type control - inlet guide vane variation mechanism

Ingestion temperature at design point 0C 30

Type of drive electric motor (direct type)

Maximum speed min-1 1000

Sealing air fans

Minimum number one fan for each pulveriser.

Safety margins

• delivery head % 110

• capacity % 121

Type radial

Type of control inlet guide vane variation mechanism

Ingestion temperature at design point 0C 30

Type of drive electric motor.(direct drive}

Maximum speed min-1 1000

Start-up and back-up firing system operating on diesel fuel oil

Capacity of diesel oil pumps %MCR 120 of fuel demand at 35 % of MCR

Firing capacity of ignition burners %MCR 35

Number of oil burners for which the boiler can achieve Its 35% MCR-Load

- n-1

Minimum turn-down ratio of diesel fuel oil burners/air system

- 1 : 5

Cooling and ignition air fans

Safety margins

• delivery head % 110

• capacity % 121

B1/FB6

245



Performance and Design Criteria Unit Data Hot reheat temperature at

• 100% MCR 0C

• 60% MCR 0C

• MSL 0C

Range of constant reheat steam temperature %MCR

Feedwater temperature at

• 100% MCR 0C

• 60% MCR 0C

Superheater spray water flow at

• 100% MCR kg/s

• 60% MCR kg/s

Reheater spray water flow at

• 100% MCR kg/s

• 60% MCR kg/s

Coal consumption for

100% MCR t/h

Boiler efficiency based on HHV for

• 100% MCR %

• 60% MCR %

Air temperature at pulverizer inlet at

100% MCR 0C

Flue gas temperature at furnace outlet at 0C

• 100% MCR

0C

• 60% MCR 0C

Flue gas temperature (uncorrected) at stake inlet at 0C

• 60% MCR 0C

• 100% MCR 0C

Excess air in furnace at

• 100% MCR %

• 60%MeR %

• MSL %

B1/FD1

246

BPDB, Barapukuria Power Plant Bidder/Contractor


Technical Data by the Bidder Unit Data

All design data of the data sheets refer to the MCR conditions and are based on guarantee points, the design coal and the reference data (Basic Design Conditions according data sheet BO/FB-1) if not otherwise stated.

General information

Type of boiler -

Manufacturer - Design code for pressure part -

Design standard for material -

Summarized performance data

Fuel: High volatile bituminous coal (gross calorific value 26,000 kJ/kg)

Heat load of boiler at • 100% MCR MW

• min. stable load (MSL) MW

live steam flaw at

• 100% MCR kg/s

• 60% MCR kg /s

• MSL kg/s

Live steam pressure (constant over the whole load range) bar

Live steam temperature at

• 100%MCR 0 C

• 60% MCR 0 C

• MSL 0 C

Range of constant live steam temperature %MCR

Hot reheat steam flow at

• 100% MCR kg/s

• 60% MCR kg/s

• MSL kg/s

Cold reheat temperature at

• 100%, MCR 0 C

• 60%MCR 0 C

• MSL

0 C

B1/FD2

247




Unburned manner in raw gas dust at 100% MCR100% MCR %

Max. unburned matter in bottom ash/slag at 100% MCR %

Number of pulverizers in operation for

• 100% MCR pc.s

• 60% MCR pc.s

• MSL pc.s

Throughput of one pulverizer kg/h

Operating data

Note:

All data refer to MCR and guarantee conditions

Water/steam flows '.

Feedwater kg/s

Live steam kg/S

supemeater spray attemperator:

• attemperator 1 kg/s

• attemperator 2 kg/s

Reheater spray attemperator kg/s

Water/steam pressure (absolute) at

Economizer inlet bar

Drum /evaporator bar

superheater outlet bar

Water/steam temperature at

Economizer inlet 0C

Economizer outlet 0C

Drum/evaporator 0C

Supporting tubes 0C

Superheater 1 inlet 0C

Superheater 1 outlet 0C

Attemperator 1 Inlet 0C

Attemperator 1 outlet 0C


Atlemperator 2 outlet 0C


B1/FD3

248




Reheater 1 Inlet 0C

Reheater 1 outlet 0C

Attemperator 3 outlet 0C

Reheater 2 outlet 0C

Flue gas temperatures

Combustion chamber outlet 0C

After supemeater 3 0C

After reheater 2 0C

After superheater 2 0C

After reheater 1 0C

After superheater 1 0C

After economizer 0C

After regenerative air preheater 0C

At stack inlet 0C

Operating times

Very cold start (drum temperature equal with ambient temperature)

Time of preparatory measures (including time for heating up the boiler via the deaerator) up to first ignition

min

Drum temperature (after preheating) 0C

Time from ignition of first burner up to MCR min

Cold start (at ambient conditions)


Cold start (after 48 hours shut-down)

Drum temperature 0C


Warm start (after 8 hours shut-down)

Drum temperature before start 0C

Drum pressure before start bar Time of preparatory measures up to Ignition of first burner min Time from ignition of first burner to MCR min

Hot start (after 0.5 - 2 hours shutdown)

Drum temperature before start 0C

Drum pressure before start bar

Time of preparatory measures up to Ignition of first burner min

Time from ignition of first burner to MCR min B1/FD4

249




Controlled load reduction after turbine trip at MCR

Time from turbine trip up to operation of boiler al MSL min

Automatic control limits for steady load change

(Rate of load variation not exceeding 1% of MCR)

HP steam pressure ±bar

Hot steam temperature ±0C

Hot reheat steam temperature ±0C

Drum level ±mm

Excess air ±%

Automatic-control limits for max. load change gradients

Rate of load change %/ min

HP steam pressure ±bar

HP steam temperature ±0C

Hot reheat steam temperature ±0C

Drum level ±mm

Excess air ±%

Technical particulars

Boiler steam/water system, Furnace

Projected heating surface m2

Volume of combustion chamber m3

Max. heat release per unit related to:

• projected heating surface MW/m2

• volume of combustion chamber MW/m3

Distance of flame boundary from boiler wall tubes m

Number of risers (wall tubes) -

Material of risers -

Riser outside diameter x wall thickness mmxmm

Tube pitching of risers mm

Furnace overall dimensions:

• height (mean) / width/ depth mxmxm

Water volume

Volume of water from economizer inlet up to drum center line m3

Volume of total superheater m3 B1/FD5

250




Steam drum

Manufacturer - Cylindrical length mm

Internal diameter mm

Plate thickness mm

Material of steel plate -

Volume of steam drum m3 Water volume up to normal water level m3

Type of internals -

Safety valves

Manufacturer -

Type - Drum safety valves

Number -

Capacity % MCR

Set pressure bar

Superheater safety valves

Number -

Capacity % MCR

Set pressure bar

Hot reheat line safety valves

Number - Capacity % MCR

Set pressure bar Hot reheat steam blow-off station Number -

Capacity % MCR Continuous bailer blow-down flash tank

Cylindrical height mm

Outside diameter mm

Blow-down rate kg/h

Boiler drain flash tank Cylindrical height mm

Outside diameter mm

Flow rate kg/h B1/FD7

251




Steel structure

Manufacturer -

Design code for static calculation -

Estimated total quantity of steel for boiler -

Platforms

Elevation of operating platforms m

Elevation of auxiliary platforms m

Boiler insulation and brick lining

Max. temperature at outer face of insulation 0C

Total heat loss of boiler kW

Design heat flux density W/m2

Refractory lining material

Denomination (type) -

Manufacturer -

Max. service temperature 0C

Operational life time h

Components which will be brick lined -

Bricksetting material

Denomination (type) �

Manufacturer -

Form of delivery -

Refractories �

Operational rife time h

Components for which Bricksetting will be applied �

Sootblowers

Number of blowing cycles per day --

soot towers of SH

Numbers of sootblowers pcs

Type �

Soot blowers for economizer

Numbers of soot blowers pcs

Type -

Soot towers of RH

Numbers, of sootblowers pcs

Type -

B1/FD8

252




Soot blowers for combustion chamber

Numbers of soot blowers pcs

Blowing medium -

Type

Coal preparation and burning equipment Coal bunkers

Manufacturer -

Number of bunkers pcs

Type of construction -

Material -

Inner lining material -

Thickness iron sheets mm

Capacity of each bunker t

Size of gate valve mm

Chute material

Coal feeders

Manufacturer -

Number pcs


Capacity kg/h

Design coal density kg/m3

Operation range -

Conveying width mm

Max. bed coal height mm

For withstanding an inside explosion pressure of bar

Rated power kW

Inner lining material -

Chute material -

Coal mills Design Coal

Worst Coal

Number of mills pcs

Manufacturer -

Type / Model -

Capacity per mill. max. after 3.000 operation hours kg/s

Capacity per mill at MCR (n mills in operation) kg/s

Capacity per mill at MCR (n-1 mills in operation) kg/s

Fineness of grinding (oversize on 0.09 mm sieve at 550) %

Temperature downstream of mill 0C

Hot air mass flow rates per mill kg/s

B1/FD9

253




Design Coal Worst Coal

Hot air temperature at mill inlet 0C Pressure difference between primary air inlet and separator outlet

mbar

Cold air mass flow rate per mill kg/s

Cold air temperature 0C

Power consumption at Coupling at MCR per mill kW Type of gear -

Weight per mill incl. gear and motor t

Cooling water mass kg/s

Mill driving motor Manufacturer -

Type -

Rating kW

Rated voltage kV

Speed min1

Primary air fans

Manufacturer . Type of construction -

Number pcs

Capacity of each fan (m3 at 00C, 1013 mbar) m3/h

Total head mbar

Air temperature 0C

Drive:

• power kW

• speed rpm

Efficiency at MCR % Seal air fans

Manufacturer - Type of construction -

Number per boiler pcs

Capacity of each fan (m3 at 00C, 1013 mbar m3/h

Total head mbar

Air temperature 0C

Drive:

• power kW

• speed rpm

B1/FD10

254



Technical Data by the Bidder Unit Data Inerting system for coal mills and coal pipes and ducts Medium used for inertisation - Quantity of medium required kg/h PC burners Manufacturer - Type/model -/- Number of burners per boiler pcs Pressure loss in the burner (air side) mbar Proportions of primary/secondary/tertiary air % Coal flow rate per burner at MCR and design coal kg/s Flame detection equipment type Number of flame detectors pcs Weight per burner t Position or burners in furnace - Diesel oil start�up and backup burners Number of burners pcs Manufacturer - Type/model -/- Max. firing capacity per burner MW Total diesel fuel oil now rate at 35% of MCR kg/S Oil pressure at burner inlet bar Flame detection equipment type - Manufacturer of high energy electric ignition equipment - Number of electric ignitors per burner pcs Diesel oil supply system Number of tanks pcs Tank capacity m3 Tank diameter m Cylindrical height m Tank weight (empty) t Number of oil pumps pcs Capacity per pump t/ h

Oil pressure at pump outlet bar Manufacturer of pumps - Type Rating kW Rated Voltage kV Speed. min1 Pressure at control valve Inlet bar

B1/FD11

255




Diesel oil slope tank

Cylindrical length mm

Outside diameter x wall thickness mmxmm

Tank capacity m3

Diesel oil slope pumps

Manufacturer -

Type -

Number of pumps pcs

Flow rate per pump Kg/s

Diesel oil unloading pumps

Manufacturer -

Type -

Number of pumps pcs

Flow rate per pump Kg/s

B1/FD12

256

Steam Turbine Plant

257

B2. Steam Turbine Plant

2.1 General

This specification covers the design, manufacturing and supply of one reheat steam turbine generators with associated systems. Steam turbine generator is rated 250 +10% MW.


This section sets out the "scope of the installations covered by this specification as well as requested supplies and services, but without excluding other necessary components and services not mentioned.

2.2.1 Steam turbine generator

Steam turbine

1 (one) reheat condensing steam turbines complete, each one including at least:

• emergency stop valves complete, including the necessary blow-out provIsions

• steam strainers for installation in the emergency stop valves or including housing for installation in the live steam line and reheat line

• electro and hydraulically operated control valves at the inlet part of the HP section of the turbine

• electro and hydraulically operated combined or separate intercept! emergency stop valves before the IP section of the turbine

• hydraulically operated control valves for LP-steam admission

• check valves and motorized isolation valves for LP bleed to the deaera-

tor/feedwater tank

• motorized turning device, complete, with manual turning equipment

• gland steam system complete with gland steam condenser

• complete noise and heat insulation

• turbine enclosure, complete

• fire protection equipment .

• all connecting piping, fittings, safety devices, fastenings,-etc.

• static and dynamic calculation or the turbine foundation (including deflection calculation due to occurring forces and moments).

Turbine oil plant

Lubricating and control oil plants for the turbine generator complete. including at least:

258

• oil tank including oil strainers • main oil pump preferably direct driven"

• auxiliary oil pump (100%) with AC motor drive

• emergency oil pump with DC motor drive

• jacking oil pumps one with AC, one with DC motor drive (if applicable)

• control oil pumps with AC motor drive (if separately necessary)

• oil vapour extraction fans with AC motor drive with oil separation in the piping • oil coolers • double oil filter for the complete lubricating oil flow • double oil filter for the complete control oil flow • all connecting piping, fittings, non return valves. safety devices. fastenings., supports of

the oil system. Sheet metal ducts for oil piping and other oil spray protection equipment.

• connections for mobile purification plant ' . • 1 (one) common mobile oil purification plant for all turbine oil systems

Waste oil disposal system

Drains for oil tanks, oil coolers, etc. to liquid waste basin including all required piping, filters, valves, instrumentation etc.

Downtime Ventilation Plant 1 (one) transposable downtime ventilation plant to avoid down time corrosion, complete with air drying plant, etc.

Condenser

2 (two) condensers, complete. with spring sponsor expansion compensators on the on the steam duct, with hotwell, condensate level control etc., each including at least:

• vacuum breaking device

• all connecting piping, safety devices, fastenings, etc.

• 1 (one) steam/air ejector for start up complete.

• 2 (two) evacuation units for the steam side with steam/air ejectors, complete with vacuum condensers, piping, valves, fastenings, etc,.

• evacuation connections to vacuum parts of the plant complete with piping, valves etc.

• 3 (three) half load main condensate pumps complete, each with motor drive and minimum flow device.

• Automatically controlled condenser sponge ball cleaning system with automatic sorting & and counting of the balls, complete including screens, ball circulating pumps, connecting piping, fittings, fastenings, local control, monitoring and switchgear equipment, etc.

Turbine bypass stations

Separate HP and IP steam bypass stations (each bypass line equipped with

259

1 (one) emergency stop valve and 1 (one) reducing valve), complete with the associated actuating and control equipment, piping from the station(s) to the cold reheat line/to the condenser and from the feedwater/main condensate line to the injection points.

Control and monitoring equipment

All control, governing, measuring and monitoring equipment, instrumentation necessary to match particular design arrangements of the apparatus and units, including

• electro-hydraulic turbine governor

• jump and rate limiter

• monitoring and protection system complete

• instrumentation and monitoring

Generator and electrical auxiliaries

• 1 (one) synchronous AC generator with complete cooling system as follows:

• internal closed-cooling cycle with air-to-water coolers (incl. one stand by cooler) as preferred solution, or alternatively

• internal closed-cooling cycle with water cooling directly through stator winding and rotor winding and internal closed-cooling cycle with air-to-water coolers (incl. one stand by cooler) for remaining parts,

• complete compounded excitation system (static or brush less rotating system) (the Bidder shall mention the reason why he did choose what) and A VR with power factor control,

• generator control panel,

• generator star point and terminal cubicles,

• complete generator busducts up to generator step-up transformer and unit auxiliary transformer, including isolators, surge arrestors, voltage and current transformers, etc.,

• generator and unit protection, synchronization, measuring, metering and monitoring equipment,

• associated equipment including CO2 fire protection, pipework, control etc.

2.2.2 Feedwater pumps

For steam generator 3 (three) feed water pumps , 62.5% capacity each including flow control devices, two in operation and one as stand-by, complete with electrical drive, nonreturn valve, hydraulic fluid couplingt base plates, ,drive motors etc. and speed increasing gear.

For each pump set:

260

• 1 (one) complete minimum-flow system including minimum-flow valve, flow measuring device, start-up line etc.

• 3 (three) booster pumps complete (if applicable)

Control equipment and monitoring equipment

All necessary local and remote instrumentation control and monitoring equipment with a scope at least conforming to the corresponding descriptions plus further instrumentation needed for adaptation to special versions of equipment.

2.2.3 Feedwater heating system

For power unit to be supplied at least:

Combined deaerator/ feedwater tanks

1 (one) feed water tank with deaerator complete, with supporting structure all stub pipes, stiffeners, baffle plates, steam heated stand pipe, separate warming up steam line strainers upstream the deaerator spray nozzles, vapour extraction system etc.

HP feed heater 6

1 (one) HP feedheater complete with supporting structure, fastenings, connection branches, safety valve, level indication, condensate level control

HP feed heater 5

I (one) HP feed heater complete with supporting structure, fastenings, connection branches safety valve level gauge condensate level control

HP-feed heater emergency bypass system and condensate emergency drain control

LP feed heater 3

1 (one) LP feedheater, complete with supporting structure anchorage, level gauge and condensate level control, etc.

LP feed heater 2

1(one) LP feedheater, complete with supporting structure, anchorage, level gauge and condensate level control, etc.

LP feed heater 1

1(one) LP feedheater, complete with supporting structure, anchorage, level gauge and condensate level control, etc.

261

Separate desuperheater (if applicable)

1 (one) HP desuperheater for HP feedheater, complete with supporting structure, etc.

Control equipment and monitoring equipment

All necessary local and remote instrumentation control and monitoring equipment with a scope at least conforming to the corresponding descrip-tions plus further instrumentation needed for adaptation to special versions of apparatus and equipment.

2.2.4 Piping, insulation

Piping, valves and accessories

All required piping as far as not included in the other sections (as e.g. steam generator plant, water treatment systems, auxiliary systems) including all accessories such as drains, vents, valves, safety devices, steam traps, condensate drainers, strainers, actuators, pipe supports, anchor points, expansion joints, nozzles for instrumentation and control fixtures, flanges, gaskets, connection elements, calibrated pipe pieces for expansion meas-urements, silencers for blow-off lines, lines and bypasses for start-up lines etc.

Insulation

• Heat conservation

• Personnel protection

• For the prevention or the formation of condensation at piping, valves etc., with surface temperature less than dew-point of ambient air

• Noise insulation to the extent necessary

2.2.5 Vessels

Cold condensate tank

2 (two) cold condensate tanks, complete.

Atmospheric flash tank

2 (two) atmospheric flash tanks, complete

Drain condensate tank

2 (two) drain condensate tanks, complete, including required drain condensate pumps Tank, vessels where these are not already included in the other sections of the specifications.

262


2.3.1 General

The requirements specified in no under section 'General Technical Re-quirements' are to apply and, where applicable, further regulations from the other sections of this specification.

The turbine generators and the respective associated equipment are to be able to be operated without any restriction and any limitation in time at each load between no-load and maximum load.

Grey cast iron will not be accepted in general. If there should be grey cast iron contained in a series-manufactured small part which is under consid-eration, the express approval of the Owner/Owner's Representative's Representative is necessary.

Stub pipes on the casings and larger constructional parts must have a minimum wall thickness of 5 mm; the minimum nominal bore is 20 mm. If flanges are provided, these are to be at least of nominal pressure 25 bar.

The control valves are to be operated in each case with auxiliary energy. Direct acting control valves will be accepted only for gland steam controller.

2.3.2 Steam turbine

Casing

The steam turbine is to be designed to ensure a very good and rapid adap-tion of the turbine to alterations in load and alterations in the steam condi-tions.

In order to be able to check the condition of the turbine blading without opening the casing, borescope openings are to be provided at suitable points on the casing.

In order to allow for rapid assembly and dismantling, the turbine casing is to be split horizontally and supplied with guides to permit safe lifting of the casing.

The casing and their built-in features is to be supported centrically as far as possible. The design and surface preparation of the supports are to be such that thermal expansion is not prevented. Packing plates shall be provided to enable good alignment to be achieved.

Blading, nozzle segments

Rotor and stator blades, nozzle segments and control parts are to be pro-duced in erosion and corrosion resistant material (stainless steel).

263

For all rotor blades, only fully machined or pre-forged and mechanically machined designs are permissible. For the first rotor blade stage only milled shrouds are permitted (shroud band integral to the blade and formed by . machining). The low pressure rotor blades are to be provided with addi-tional edge protection, where necessary. The turbine stages operating in the steam region are to be provided with sufficient water drains.

Rotor

The coupled critical speeds of the turbine and generator rotor must lie outside the range from 85% to 120% of the nominal speed. The rotor is to be statically and dynamically balanced in the factory.

It must be possible to re-balance the rotors on site without particular diffi-culty. The fixed parts of the steam turbine plant must be free of any reso-nance which might disturb the operation .

In the design of the rotor, all notches, sharp inner edges or excessively small radii are to be avoided so that fatigue failures are excluded. All internal radii arc to be provided with a high quality surface finish.

Bearings

Basically, the bearings are to be designed as horizontally split plain bear-ings. The thrust bearings must be capable of taking load from both sides and be self-aligning. They must be axially adjustable.

It must be possible to check the thrust bearing wear during operation.

Earthing brushes are to be provided at the turbine side bearing of the generator to protect the bearings. Similarly the necessary bearing and pipe insulation must be provided to give protection against eddy currents. In order to prevent oil leaks, suitable bearing seals such as oil thrower rings are to be provided.

It must be possible to dismantle the bearing shells without removing the turbine casings or dismantling the generator.

Gland steam

Gland steam must not be discharged into the turbine hall. The labyrinths to be provided should have spring elements if possible. It must be possible to inspect the outer labyrinth through a removable cover without having to open the turbine.

The gland steam system is to be provided with a gland steam and vapour condenser and vapour suction fans. The materials to be used for the gland steam condenser shall be of stainless steel material.

264

Emergency stop valves, governor valves, reducing valves

Spindles, fittings and control parts are to be manufactured in stainless steel material. The guide surfaces are to be manufactured in hard wearing materials or they must be armoured. Spindle leakage losses must be avoided by suitable seals.

In order to facilitate the safe and reliable shut-down of the machine, the emergency stop valves and governor valves must be arranged with easy access as near as possible to the appropriate turbine casings. In so far as flange connections are provided on the live stearn side, these are to be executed as high quality designs.

Turning device

Hydraulic or electrically driven turning devices may be employed. The turning device must disengage automatically as soon as the turbine speed exceeds the turning speed. Automatic engaging of the turning device must be foreseen remotely from the central control room and manually from local position. A manual turning gear provision should be included for the black periods.

If jacking oil pumps are used they are to be interlocked so that turning without jacking oil supply is precluded. Interconnection between the lubricating oil supply and turning operation is to be ensured by automatic interlocks.

Couplings

If toothed couplings are employed, these are to be provided with forced oil lubrication. All parts of toothed couplings are to be fully machined. Coupling hubs and sleeves are to be individually balanced, statically and dynamically, at a speed corresponding to the operating speed. For the design the short circuit shock has to be assumed at least 8 times the nominal torque on the drive coupling for at least 100 times. If necessary, this value is to be corrected upwards after the torsional critical speed calculations for the total plant and the actual generator short circuit torque are known.

Other turbine equipment

The turbine bleeds above I bar are to be provided with bleed steam emergency shut off or emergency check valves.

2.3.3 Lubricating and control oil system

The lubricating and control oil system serves to supply the lubrication points and the control equipment of the steam turbine. The oil supply equipment is to be arranged in a separate oil room.

The temperature rise of the bearing oil in the bearings must not exceed 30 K, and the oil drain temperature of the bearings must not exceed 75 0C.

The oil tank is to be dimensioned so that the content is not changed more than 10 times per hour.

265

Oil vapour suction fans and oil separators are to be provided. The possibility of unacceptable concentration of the oil vapour must not exist at any point of the oil system.

All oil-carrying parts must be separated from equipment subjected to hot steam so that premature ageing of the turbine oil and the danger of fire is excluded. The oil pipes must be run in separate oil ducts away from the cables.

The oil pipes must be seamless and connections between oil-carrying parts must be welded or flanged. Flange connections of the oil pipes outside oil ducts and turbine oil room must be encapsulated. The fastening of the oil pipes must be such that excessive vibrations are excluded. Oil drain points are to be equipped with double stop valves. It must be possible to shut off the control oil circuit separately.

The auxiliary oil pumps should he arranged on the oil tank. The auxiliary oil pump must be able to start automatically in the case of a drop in oil pres-sure. If positive displacement pumps are employed, pressure relief valves must be provided in each case for the full flow quantity. To avoid an unallowable drop in pressure during switch over of oil pumps, a pressure accumulator is to be installed in the oil system (if necessary).

The DC emergency oil pump has to be connected electronically in a failsafe way. It has to be ensured by proper means so that the pump is always working in emergency cases. Off-command from the central control room shall only be possible in case of turbine standstill.

The oil coolers are to be provided with a withdraw able tube bundle. If2 coolers are installed; they must be switch able during operation without interruption of the oil flow and must be easy to clean. The coolers are connected to the closed circuit of the plant auxiliary cooling water system. The materials used for the oil coolers shall be equivalent to the materials • specified for the gland steam condenser.

The oil filters in the lubricating oil main circuit and in the control oil circuit are to be arranged as duplex filters which can be switchover without interruption.

In addition, an oil separator (preferably of the centrifuge type) with all auxiliary equipment is to be provided for at least 3% of the circulating oil flow. The separator shall be capable of being used both in operation and when the turbine is out of service. Those parts of the oil separator in contact with fluid are to be manufactured from stainless material. Dirt and all solid particles greater than 5 microns are to be removed in the oil separator. However, oil additives of any type should not be removed from the oil. It is necessary that an oil vapour extraction must be provided for this equipment. The oil separator delivered shall be of the self-cleaning design.

The different oil systems are to be made easily distinguishable by a clear arrangement and different colouring.

A suitable sampling device shall be provided for the oil tank.

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The scope of the system should include the lube oil transfer pump and motor, clean and dirty storage tanks and lube oil conditioning equipment. All piping from the lube oil storage tanks to the lube oil conditions, to the main turbine reservoir and the lube oil conditioner to the rooftop vents is included.

2.3.4 Insulation

In order to avoid a possible penetration of oil, insulation with an oil-tight hard cover is to be provided for the turbine. Damaging heat radiation on to� the foundations must be avoided.

Asbestos insulating material will not be accepted.

Hot sections which cannot be insulated, such as for example observation openings, are to be provided with a corresponding contact protection.

All external thermal insulation shall be of the blanket type and be capable of removal and replacement for overhaul purposes without damage. Thermal insulation shall be provided, where appropriate, to prevent adjacent concrete surfaces from reaching excessive temperatures.

2.3.5 Turbine cladding

The turbine cladding is to be designed as a sheet metal cladding with noise insulation and provided with sufficient corrosion protection. It shall cover the complete turbine area including the turbine outer bearings. Heat build-up within the turbine cladding is to be avoided by suitable ventilation.

2.3.6 Downtime ventilation

The maximum relative humidity in the turbines during standstill downtime periods shall not exceed 40% under all possible ambient conditions and suitable airdrying plant and connections shall be provided for the ventilation. The air guidance within the unit to be protected is to be arranged so that all parts experience a sufficient flow. The ventilation equipment is to be designed for at least two air changes per hour referred to the volume to be ventilated.

2.3.7 Fire protection equipment:

The fire protection equipment shall be provided as far as applicable.

The lubrication and control oil areas shall be provided with:

• automatic fire detection and alarm system

• utilizing flame and heat detectors

• automatic fixed fire extinguishing system with alternative manual operation 2.3.8 Condenser

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The design of the condenser shall comply with the design data of the turbine generator. In dimensioning the heat exchange surface it must be assumed that all the load cases must be met even if 10% of the condenser tubes are blocked. Under-cooling of the condensate is to be avoided. The pressure design on the steam side must at least cover the range from full vacuum to bar gauge and, on the water side, at least 3 bar gauge.

The water side of the condenser is to be divided into two independent halves. Each half must be so dimensioned that the turbine generator can be operated with corresponding decreased load while the other half is out of action. The condenser has to meet the requirements of the main cooling water system with respect to material. The Contractor must show that sufficient experience with the chosen material is available; in particular reference shall be made to the expanding of the tubes into the tube plates and the welding of the tube plates to the condenser shell.

Dangerous vibrations of the condenser tubes must not occur during opera-tion. Therefore a corresponding number of carbon steel tube support plates must be employed. If necessary, baffles are to be provided to protect the tubes. The holes in the tube plates and tube support plates shall be accu-rately drilled, renamed and chamfered on both sides to facilitate assembly of the tubes. Sufficient space is to be provided for withdrawal of the condenser tubes.

Each half of the water chamber shall contain venting and water drain connections of adequate size. Sufficient and manually actuated venting at the cooling water side in case of sudden outage of the main cooling water pumps is to be provided. The water side of the condenser is to be designed so that satisfactory functioning of the continuous condenser cleaning equipment is ensured.

The water side of the condenser is to be designed so that satisfactory functioning of the condenser cleaning practice by chemicals is ensured.

The arrangement of the condenser must be such that no unacceptable forces can be exerted due to thermal expansion, over-pressure or. the filling of the steam space with water.

In addition, the condenser must be suitable for accepting all drains occurring during start-up or operation.

A suitable number of manholes with internally held covers is to be provided on the steam and water sides of the condenser having at least a nominal bore of 500 mm. Furthermore, means of observing the vulnerable condenser tube regions must be provided.

The capacity of the hotwell shall correspond to a condensate flow of at least 2.5 minutes during full load condenser operation. The complete control loop for controlling the hotwell level including minimum condensate flow and control valves is part of the condenser. Local pneumatic control devices are not

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accepted.

AIl connections in the vacuum area must be welded.

2.3.9 Continuous condenser cleaning equipment

The condenser shall be equipped with a sponge baIl condenser cleaning system. This equipment shall be controlled locally. For this purpose a local control panel and all interconnecting cables for measurements and motors shall be provided. The local control panel shall contain all necessary control and switchgear equipment and shall require only one feeder. Potential-free contracts shall be available for annunciations in the central control room of any fault in the condenser cleaning part.

2.3.10 Turbine bypass stations

The turbine bypass stations serve to remove surplus steam from the hot reheat steam line into the condenser in case of start-up/shut-down or turbine trip as well as HP steam into the cold reheat line. The bypass stations arc to be provided completely with pressure and injection water regulation. It must be suitable for automatic operation. The opening of the by-pass valve is to be interlocked with pressure checks for injection water pressure and condenser pressure. The pressure setting must be adjustable. Turbine bypass operation must be possible without time restrictions. This system should be sized for approximately sixty (60) percent, of the normal main steam flow.

2.3.11 Evacuation units

Either steam ejectors or waterring pumps may be employed for maintaining the vacuum in the condenser. They shall be designed sufficiently large to maintain the vacuum in the condenser even with small leaks. The start-up vacuum shall be provided by means of a start up evacuation unit.

2.3.12 Main condensate pumps

The rate of delivery of the main condensate pumps should be at least according to the quantities in the worst combination of their occurrence.

The delivery head of the main condensate pumps is to be stated by the Contractor.

Casings and rotors are to be provided with wear rings in order to permit easy replacement of the parts subject to wear. Condensate from the dis-charge pipe is to be used as sealing water as far as required .

The pump motors are to be so designed that even with 25% overload the pumps will not be switched off. Pumps and driving motors are to be sup-plied on a common base plate.

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The installation height of the pumps and the NPSH value of the pumps are to be matched to one another so that there will be sufficient suction head even under the most extreme operating conditions.

2.3.13 Generator and generator main connections

Generator

The generator shall operate satisfactorily as a single unit, in parallel with the other unit and with the grid system under all normal working conditions and shall be designed for continuous operation.

The connections of the generator and the auxiliaries are indicated in the tender drawing "General Single Line Diagram".

The generator shall be of the 2 pole cylindrical rotor type.

Generator stator

The casing of the stator should be of fabricated steel construction.

The stator core has to be made of high permeability low loss stampings, tightly clamped together to reduce noise and vibration to a- minimum. Attention will be given to prevent excessive vibration at twice rated fre-quency being transmitted to the generator foundations, pipes or associated equipment.

The stator winding is to be star connected and should be so designed such that the replacement of a damaged portion is a relatively simple matter. The winding shall be effectively braced and blocked to withstand without being permanently disturbed, the forces set up by single phase or three-phase short circuits at the terminals. The general construction of the stator and the bracing of the winding overhang shall be such as to provide adequate cooling surfaces and the avoidance of hot spots.

Suitable anti-condensation heaters has to be provided which will be ener-gised automatically when the generator is shut down.

Generator rotor

The cylindrical rotor body shall be of forged steel, comprising one solid forging. After rough machining the forging shall be subjected to 100% ultrasonic examination. Damper windings or damper wedges have to be fitted as necessary to prevent cyclic irregularities and as a precaution against local overheating of the rotor surface.

The design of the rotor cooling system should ensure that no hot spots develop. The packing blocks used in the rotor winding has to be of approved materials and suitable for the high temperatures and mechanical forces which exist in the rotor.

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Particular attention will be given to the insulating and securing of the rotor winding and its connections to avoid vibration and the possible failure of either conductors or its insulation. Rotor retaining rings will be thoroughly tested before application to the generator rotor (ultrasonic penetrate inspection).

An earthing brush has to be fitted at a suitable position on the shaft, which is free from contamination by oil etc. Brush changing should be possible safely and easily while the generator is operating. Where necessary suitable precautions shall be taken against harmful flow of shaft currents by the provision of insulating bearings. Insulation provided for this purpose has to'" be designed to withstand a test voltage of 2 kV AC.

Generator bearings

The bearings shall be of the metal sleeve type and designed so as to be readily accessible and replaceable without the removal of the rotor.

All bearing oil wells shall be provided with visual oil level indicators and ready means of checking oil flow, filling and draining.

Thermometer pockets must be provided on each sleeve bearing with a dial type thermometer with adjustable alarm contacts to provide. warning of excessive oil temperature ..

Bearings dependent on lubricating oil has to be provided with a complete and approved lubricating oil system capable of maintaining the continuous operation of all parts of the machine, without undue heating, at all loads, together with the necessary equipment to provide suitable lubrication during normal start-up and shut-down, emergency shut-down, barring and all other conditions. The system for the generator will be part of that for the prime mover and automatically maintained.

Generator excitation system

Provision shall be made for testing the excitation equipment without the operation of the main generator.

A brush less rotating diode type (RE) of excitation system or a terminal-fed static excitation system (SE) may be supplied, provided the Bidder/Contrac-tor can prove this is his standard system and there is proven and extensive experience on installations in similar locations to the Site.

A block diagram of the complete excitation system has to be supplied together with the constants of the transfer functions for the control and stabilizing circuits. The time constant of the exciter shall also be included.

The over-current capability for the generator shall be 150%, 30 s.

The nominal exciter response has to be not less than 0.5 s�1.

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The continuous rated current and voltage of the main exciter has to be not less than 110% of the generator excitation current and voltage required to maintain rated output at the terminals of the generator. The ceiling voltage must not be less than 200% of maximum continuous rating.

Rotating exciters have to be of the enclosed ventilated type. IP54. They will be directly driven by the generator.

Anti condensation heaters shall be provided in the air circuits of the exciter. The leads from the heaters has to be brought out to an isolator located close to the bed plate with suitable interlocks provided to energise the heaters with the generator at stand-still.

Ventilating air for rotating AC exciters should be closed circuit cooling. incorporating an air-to-water heat exchanger. and shaft mounted fans.

Generator exciter

• Rectifiers for RE system

The rectifier bridge will comprise a simple three phase full wave configura-tion. Each bridge arm shall consist of a number of diodes in parallel per arm with suitable protection incorporated.

Particular attention should be paid to the full load and field forcing require-ments of the generator in addition to the protection of the diodes.

The repetitive peak reverse voltage rating of the diodes in each arm of the rectifier bridge shall be greater than the maximum reverse voltage appearing across an individual diode by a factor of at least 2.0. The maximum reverse voltage appearing across the rectifier bridge will be determined from a calculation of the induced voltage following a faulty synchronization.

Suitable surge suppression equipment shall be provided across the rectifier bridge if necessary to afford overall protection of the rectifier against excessive over voltages

In order to protect the diodes when connected in parallel. either each diode should be protected by an H.R.C. fuse together with individual R-C circuit suppression and diode failure indication or. if the Bidder/Contractor can demonstrate that individual fuse protection is not required. consideration • will be given to incorporating such fuse protection in the AC leads from the exciter. Preference will be given to those schemes uti!ising diodes of sufficiently high peak reverse voltage capability such that the requirement for individual diode R-C circuit suppression may be elimin;1ted.

The diodes in the rectifier bridge has to be continuously rated such that generator full load. field forcing, fault conditions and a reserve capability of at least 20% can be carried with one failed device per bridge section. A diode failure detection device is required to monitor all diodes forming the

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rectifier assembly. The Bidder/Contractor should describe the method used to detect and report such failures and the resultant action of the excitation system.

Rectifiers for SE system

The thyristor converter shall incorporate a number of three phase full wave , bridges, and has to be arranged so that a minimum of20% reserve capacity is incorporated. The converter should be of modular construction so that a minimum of one bridge may be removed for maintenance (shut-down required), which still allow full load excitation and unit operation without any restrictions.

In the event that the converter derives its AC power requirements from the main generator terminals, the excitation supply transformer should be capable supplying full field forcing voltage at 80% of rated generator output voltage. In addition a permanent DC control supply for electronic circuits will be provided with such a method of converter supply.

The thyristors are to be protected by line or arm H.R.C. fuse as appropriate. and may operate in connection with suitable crow-bar circuits. Indication of thyristor failure has to be provided. Provision shall be made in the design of the converter for the protection of the thyristors against gross over voltages.

The repetitive peak reverse voltage rating of the thyristors in each arm of the three phase bridges of the converter has to be greater than the maximum reverse voltage appearing across an individual thyristor by a factor of at least 2.0.

Suitable surge suppression equipment shall be provided across the input of the converter unit to ensure overall protection of the converter.

Provision has to be included for the detection and annunciation of excess heat sink temperatures.

The thyristors shall be continuously rated such that generator full load, field forcing and fault conditions can be carried with one failed device per bridge section.

Generator voltage regulation

The excitation control equipment shall consist of automatic voltage regula-tor of the static type with single channel together with a manual control device. The system must be capable of either automatic and manual opera-tion and will incorporate appropriate auto/manual changeover facilities. Local and remote set point control shall be provided for both automatic and manual control.

The system shall include suitable limit control features, fault detection and protection features and where appropriate generator transformer overfluxing protection. In the event that dual channel operation is offered,

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the standby AVR channel will be continuously monitored, and system operation and protection shall be unaffected by transfer of control from one channel to another.

The thyristor output stage of the excitation control equipment must be continuously rated for the excitation demand of the generator at full load, field forcing under fault conditions and a contingency of 75%.

Generator automatic voltage regulator (AVR)

The A VR shall be of the continuously acting type with no dead bands enabling control of the excitation over the whole generator operating characteristics. The AVR must be capable of maintaining the generator terminal voltage within ± 0.5% of the set value for any voltage deviation over the whole load range of the generator.

The voltage response characteristic should be given by the Contractor for AVR damping control at normal, maximum and minimum settings.

The AVR must be equipped with an active power dependent voltage stabilization circuit (Power System Stabilizer) for damping rotor oscillations.

Generator excitation limiter

A minimum excitation limit device has to incorporated to prevent the AVR reducing the generator excitation below a value which might endanger power system stability limits. The limit unit shall be arranged to provide an alarm and interlock in the event of extreme low excitation when operating under either automatic or manual excitation control.

The characteristic of the var-Iimiter must be adjustable and facilities should be provided so that the var-Iimiter operating characteristic can be adjusted to any setting within the specified range.

Over-excitation protection must be incorporated to ensure that if excessive excitation is sustained beyond an adjustable present current/time limit, the A VR is either tripped or the excitation is automatically ramped down. The current/time setting must be such that no damage will be caused to any part of the A VR or to the excitation rectifiers.

The AVR shall in addition include the following protective devices which will trip the AVR to manual control and initiate appropriate alarms and still trip the set after a predetermined delay in the range 0-30 min.:

• Overvoltage protection

• Overcurrent protection

• V.T. fuse failure protection

• AVR failure protection

• Overfluxing protection (volts/Hz protection)

• A VR power supply failure protection.

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Overnuxing protection must be provided and will be part of the excitation control system and shall be operative during both automatic and manual modes of excitation control. The protection has to prevent the transformer magnetic flux from rising to a value at which the voltage/frequency ratio, pre-set within the range 1.00 to 1.25, would be exceeded.

Generator control

An approved means of manually controlling the excitation must be provided primarily for generator commissioning and maintenance purposes. Control will be possible from approximately 0 to 110% UN.

Means for both local and remote (from central control room) operation or the manual control shall be provided with

• auto/manual balance indicator (local cubicle and central control room).

• changeover switch (local cubicle and central control room).

However, remote changeover should be inhibited when the local control is III use.

A follow-up device must be provided to automatically adjust the standby manual excitation control so that in the event of a changeover from automatic to manual control here will be a minimum change in lhe level or excitation.

All automatic limiter shall stop the automatic folIow-up device or the manual voltage controller from reducing the manual voltage regulator selling below the prescribed are limits of excitation for the generator when under manual control. The characteristics or the limiter shall have the same range of adjustment as the var-limiter of the AVR channel, but when commissioned will be set for less leading conditions than the var-limiter.

Generator droop compensation

Quadrature droop compensation must be provided to ensure correct sharing reactive power in accordance with generator rating. The compensation shall have an adjustable compensation range of ± 10% and has to be so connected that the compensation can readily be taken out of service.

Generator exciter field suppression equipment

The exciter field suppression equipment shall be provided and may be accommodated within the AVR cubicle. The field switches must be capable of making and breaking the circuits under the most onerous fault conditions. The switches shall be suitable for local and remote as well as automatic operation. The generator field switch must also be suitable for manual operation.

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Means has to be provided on the cubicles for indicating locally and remotely whether the switches are in the 'open' or 'closed' position.

The field suppression resistor shall be non-inductive and rated to suppress maximum field current as quickly as possible.

Generator sliprings and commutators

Where slip rings, commutators, and associated brush gear are provided they must be designed to operate without injurious sparking or excessive wear and it shall be possible to run for Ht least four months without replacements of the brushes. The brush gear housing has to be designed to provide maxill1umvisibility via inspection windows. Guards of insulating material should be mounted between the slip rings and between brush holders of opposite polarity.

Approved arrangements shall be made for locating and operating a grinder for grinding surfaces. The grinder has to be supplied under this Contract.

Slip rings and commutators should be in a separate cooling medium circuit so that dust from brush gear wills not enter the exciter generator windings.

Generator temperature measurement equipment

Pt 100 temperature detectors and indicators of approved type shall be provided for measuring the maximum internal temperature of the generator and the cooling medium temperatures. The positions will be subject to agreement and provision should be made for the following requirements:

• stator windings, between coils in slot 9 positions • cooled air from coolers (per cooler section) 1 position • hot air from generator (per cooler section) 1 position • direct cooling water (if applicable) 18 positions • exciter cooling air inlet 1 position • exciter cooling air outlet 1 position • bearings (generator and exciter) 2 positions each • spare on terminal board for test purposes 2 positions.

Each indicator must have adjustable settings for initiating a high tempera-ture alarm which shall be independent of the temperature indication se-lected.

The leads from the temperature detectors have to be brought out to a terminal box on the generator in a position which is accessible during normal operation of the set. All temperature detectors shall Rave the same characteristics. A multi-point temperature indicator with selector has to be mounted in the central control room.

Generator cooling equipment

The generator cooling system must be complete and include all necessary

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coolers, fans, pumps and control apparatus as required for safe and efficient operation of the plant and has to comply with the requirements of IEC 34-3.

As cooling systems the following has to be provided:

• Internal closed-cooling cycle with air-to-water coolers (incl. one stand by cooler) as preferred solution, cooling classification of complete generator IC7A1W7,

or alternatively

• internal closed-cooling cycle with water cooling directly through stator winding and rotor winding together with internal closed-cooling cycle with air-to-water coolers (incl. one stand by cooler) for the remaining parts, cooling classification of generator stator and rotor windings IC3(W7)W7 and of remaining parts IC7A1W7.

If H2 cooled Generator is proposed, Contractor has to supply, install 2x 100% capacity H2 Generator, 02 nos. of H2 compressor (for H2 storage bottles), H2 storage bottles, on line H2 analyzer, H2 dryer, Co2 system etc.

The generator coolers etc. must he sized so, that rated generator output at class B operation can be mainlained with 10% of the tubes blocked. The cooler and isolating valves have to be arranged to permit easy isolation and cleaning of individual sections after shut-down. With one cooler section withdrawn, the operation of the generator can be continued at rated genera-tor output, utilizing the thermal limits of class F.

The cooler tubes shall be mounted and supported to allow for the effects or expansion and vibration. Any necessary apparatus required to withdraw the air coolers or permit repair has to be provided. Water leak detectors must be provided for all coolers, which will initiate an alarm in the event of a leak occurring.

CO2 equipment

CO2 systems have to be provided, including the individual CO2 bottle storage close to each generator, the bulk CO2 storage plant (outside machine house) and all required equipment for satisfactory operation, such as piping to the generator housing and to the bulk CO2 storage plant, :valves, vaporizer, fittings, hangers, supports, control and supervision.

Generator main connections (GMC)

The GMC's are to be designed ns self-cooled isolated-phase busduct system protected against contact and designed for indoor and outdoor installation. The complete GMC system must be provided with the necessary current and voltage transformers, earth switches, star point connections for the generator, overvoltage capacitors. isolating links li)r the unit auxiliary transformer and all required fittings and internments.

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The basic circuit of the GMC's and the instrument transformers and other equipment is shown in Annex B8-2. All the necessary controls, regulating, measuring and monitoring instruments including meters are to be provided locally and/or in the central control room. The GMC's are to be designed for the thermal and dynamic maximum short-circuit currents occurring. All supporting and other constructions both inside and outside the GMC, where not made of aluminum. must be made in a hot-dip galvanized design. In the GMC-branch busduct to the unit auxiliary transformer isolating links are to be provided in the single-phase busbars. Anti condensation heaters are to be provided in each separate GMC section.

GMC generator star point

The star point is to be made directly behind the generator bushing type current transformers provided for this purpose. This high voltage section is to be enclosed by a cubicle unit with solid metal walls. The earthing trans-formers as required by the generator stator protection system may be arranged also in this cubicle if applicable.

GMC connection cubiclcs

Along the indoor run of the GMC's, all further auxiliary items such as voltage transformers, overvoltage capacitors, earthing isolators, etc. are to be housed in steel sheet cubicles.

GMC current and voltage transformers

All current transformers (CT) and voltage transformers (VT) are to be provided in accordance with lEC 144 respectively lEC 186.

A tripping time of live seconds is to be taken as a basis for the thermal stability of the transformers in the GMC's. The current transformers will be or the toroidal type, cast resin insulated.

GMC transformer and cubicle connections

The generator step-up transformers and unit auxiliary transformer are to be connected in a way that, in the event of any short-circuit forces, no harmful deformations can occur.

The distances between the individual transformer bushings and therefore the spacing and height of the main generator busducts arc to be selected so that both repair and maintenance work can be carried out without any difficulty.

In the case of three-phase terminal cubicles arc-proof partitions are to be provided between the phases for both the generator and the transformer connection.

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GMC earthing switches

Motor-driven earthing switches of short-circuit-proof design arc to be used. The necessary interlocks with the 230kV circuit breaker, etc. arc to be provided.

GMC protective capacitor

To reduce the overvaulting stress, three protective capacitors must he installed and connected to the generator main connection near the generator step-up transformer.

Generator unit protection, synchronizing, measuring

Unit protection system

For the generator and unit protection system, digital protection relay types has to be used. The individual relays or relay groups are to be installed in the plug-in principle in standardized steel sheet cubicles. The basic circuit will be as shown in Annex B8-2.

The protective relays are to be divided into two groups with the relays in group 2, for example, representing the back-up protection of the relays in group 1 and vice versa.

The subdivision of the protective relays into groups is to be associated with fully automatic self-check facilities (watch dog) enabling the protective relays self-test during operation without imposing any operating restrictions. On request the test values will be printed, values outside the allowable limits will be marked in the print and an alarm will be actuated.

The Contractor must coordinate the aforementioned protection equipment with the protection system of the 230k V switchgear and with the protection system of the grid.

Synchronizing

The general synchronizing point will be the 230kV circuit breaker. A plugin type electronic parallel-switching apparatus must be provided.

In general, the 230kV circuit breaker will be synchronized by means of the automatic program, but all required equipment for conventional manual synchronization from the local generator control panels must he provided. for this purpose, the parallel-switching measuring instruments such as twin voltmeters, synchroscope and twin frequency meters will be integrated with pushbuttons for speed regulation and voltage adjustment in the local gen-erator control panels.

In case of manual synchronizing, this will only be possible when switching-ON command is released by a separate synchro-check relay.

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Application of the appropriate voltage transformer outputs is to be effected simultaneously with the choice of synchronizing point (synchronizing selector) from the central control room. Measuring

Electrical measuring and metering equipment must be provided locally and in the central control room minimum as per the basic circuit shown in Annex B8-2.

2.3.14 Control and monitoring equipment

Refer also to the general requirements on control and monitoring in sections B9.

The regulation equipment supplied must successfully control rapid changes in load. Operation in the speed control mode shall also be possible.

The protection system supplied has to protect the turbine generator plant in every phase of operation from overload and damage. It must be continually ready for operation and capable of being checked even during operation and must not be capable of being switched off even accidentally.

The control, regulation and supervision of the turbine generator has to be complete and safe in every respect. Where required, 2-channels, 2 out of 3 logic or self-monitored systems arc to be provided.

An electro-hydraulic turbine governor system is to be employed, preferably with the hydraulic part capable by itself of providing safe operation of the turbine. The electro hydraulic governor shall embody the following func-tions:

Governor equipment

The description below contains the regulation tasks and a framework pro-posal for the solution of these tasks.

The Contractor is required to supply the range of equipment which makes possible the safe fulfillment of the tasks (\s outlined and the maintenance of the necessary regulation accuracy. In addition, the regulation circuits must guarantee stable turboset operation at all load points.

Local instrumentation shall be grouped according to process sub-systems, e.g. all instruments of control oil pressures and temperatures at a common place.

• Speed control

• Inlet pressure control/limiting

and shall fulfill at least the requirements described below:

• The turbine shall be capable of being run up from stationary to rated

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speed under speed control with a governing accuracy of 1 % or better. The system must also provide for proper management of automatic syn-chronizing.

• The speed overshoot caused by a full load shedding has to be less or equal to 8% referring to nominal speed. The same is required by only action of the mechanical/hydraulic governor.

• A facility for limiting the rate of speed variation shall be provided.

• For the speed a set point adjustment facility with presettable slope, and with limiting action on the jump and rate limiter corresponding to the allowances, shall be provided .

The electro hydraulic turbine governor must be suitable for co-operating with a functional group control system, with the jump and rate limiter described below and with a superimposed distributed control system (DCS).

All governor system status and fault conditions are to be signaled individually in the control cubicle. In the event of a fault affecting the electro hydraulic governor, the mechanical/hydraulic governor shall automatically take over at least the functions of speed governing and inlet pressure limiting.

Jump and rate limiter system

As a supplementary feature for the turbine governing system, a jump and rate limiter system shall be supplied. This shall permit rapid load following by the turbine and fast load-changing consistent with permitted levels of material stressing and taking into account the thermodynamic response of cylinder and shaft. This involves monitoring and evaluation of temperature deterrence’s at representative critical points. The critical points are to be selected by the supplier in the light on the machine design (e.g. monitoring of emergency stop valve, high-pressure cylinder and high-pressure shaft). At least two measuring points are to be monitored accordingly.

The computed allowances are to be made available to the two set point adjustment devices of the turbine governor for limiting purposes, and fed to information displays and to the DCS in the central control room. On attainment of a temperature or stress limit appropriate alarm signals arc to he initiated.

The jump and rate limiter shall be designed to be self-monitoring. Equipment faults must not lend to unacceptable limitations on operation.

Protection equipment

The protection interlock chain "Turbine protection" is to .be executed in particularly safe and high quality technology and is to he introduced into the control ns interlock criterion so that the turbine is protected from overload and damage throughout the complete operating range. The following

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protection criteria must be present as a minimum:

• Steam inlet temperature and pressure greater than max.

• Turbine speed greater than maximum [at least two (2) independent speed checks for 110/112% with the possibility of testing during continuous operation]

• Bearing metal temperatures (thrust and journal) greater than maximum

• Shaft position not correct

• Bearing housing and/or rotor vibrations greater than maximum

• Wall temperature difference of turbine casings greater than maximum

• Control oil pressure lower than minimum j

• Lubricating oil pressure lower than minimum

• Relative extension greater than maximum

• Level in lube oil tank lower than minimum

• Generator protection operated

• Fire-protection system operated

• Unit trip operated

• Local turbine trip operated

• Condensate level in the condenser

• Remote trip from the central control room

It is also necessary to guarantee that the operating personnel will he made aware of danger by alarms before the operation of the protective mecha-I11sms.

The turbine generator plant must be protected from faulty operation by preventive protective interlocks (passive protection).

All the mechanical-hydraulic and electrical protective circuits 011 the turbine must be so constructed (for example using 2-channel, 2 from 3 selection, self-monitored principles) that faults in one protective interlock cause no erroneous release, on the one hand. but do not prevent the initiation or rapid shut down in actual cases of danger, on the other. The protective circuits must be supervised by checking the equipment initiated from the central control room and it must be possible at any time to inspect the functional correctness of the protection without causing a trip of the turbine. The protection signals must operate on all turbine emergency stop valves and, where applicable, on the bleed emergency shut-off valves.

2.3.15 Feedwater pumps

The boiler feed water pumping sets shall be identical in designs and all replacement parts will he interchangeable.

Only first class approved makes of best quality will be accepted.

282

Special emphasis is placed on a high resistance to corrosion of the equipment. The feedwater pumps with all parts coming into contact with the feedwater are to be constructed in chromium steel containing at least 13% chromium. The materials must satisfy without restriction the requirements of erosion and corrosion resistance resulting from operation with dematerialized water and water conditioned with volatile alkalizing agents having a PH value equal to or greater than 7.0. Protective sleeves on the shafts arc to be hard chromium plated, cooling sections and bearing mountings of cast steel.

A reverse rotation locking devise shall be provided for each pumping unit.

The pumps must have generously dimensioned plain bearings (only for booster pumps ball bearings can be offered as an alternative) and forced feed oil lubrication. The total axial thrust of the pump shall be neutralized by a hydraulic balancing device. A thrust bearing shall be provided, which is so dimensioned that even in the event of short-duration cavitations no damage to the pump will occur. The hearing metal shall have emergency running proprieties.

The bearings must be designed to accommodate displacement of the pump impeller due to thermal expansion.

The shaft seals shall be of the soft-packed stuffing box type in the case of • booster pump and mechanical seals for main feedwater pumps. The stuffing box and corresponding gland cover shall be cooled; the seal chamber nt mechanical seals shall be cooled as well.

Removable wearing rings shall be installed on the casing and impeller at the running joints.

All rotating parts shall be statically and dynamically balanced. Each impeller shall be carefully machined and polished and where it is impossible to machine, a smooth surface shall be obtained by work.

II must be possible to start the pumps safely from cold with prior warming up. Automatic changeover to the load point previously in use must he possible without delay.

The minimum-flow devices arc to he automatically actuated. They shall include a hand start bypass. The minimum flow lines and balancing lines are to be run separately for each pump to feedwater lank

Strainers should be included in the suction lines to protect the pumps from damage under all operating conditions. The strainer mesh size should not exceed 0.4 mm. The strainer and strainer body must be matched so th:.1lthe full area of the strainer is utilized. The free area of the strainer must he at least equivalent to 5 times the cross-section m-ea of the corresponding suction pipe.

The rotor design shall be sub critical.

283

To combat vibration, the pumps should be mounted on reinforced concrete foundation slabs supported on spring elements.

The pumps casing shall be properly insulated and sound protected.

The design pressure of the feed pumps shall be at least 1.2 times the pump zero now pressure at the highest possible pump speed at cold conditions and under maximum suction pressure conditions.

Oil supply

A closed oil system having separate internal working and lubricating circuits must be provided for the feedpump and motor bearings.

The lubrication oil system shall also be equipped with an auxiliary lubricat-ing oil pump which starts automatically in the event of a fall in lubricating oil pressure. An adequate feed of oil shall be ensured under start-up and run-down conditions.

The oil systems are to be equipped with all necessary filters (double filters), strainers, pipes, valves, etc. necessary for safe operation. Changeover of the filters during operation must be possible without interruption and they must be easy to clean.

2.3.16 Feedwater tanks and deaerators

The deaerator connected to the feedwater tank should be of the spray type using the "Stork" system or of cascade-type with incorporated re-evapo-ration. In all cases the feed water tanks must have a warming-up steam line supplied with steam from the auxiliary steam header.

The size of the deaerator must be sufficient for a water flow of at least 1.1 times the maximum boiler feed water flow plus the maximum feedwater injection quantity.

If the feed water tank pressure falls, a supplementary steam supply is taken from the cold reheat manifold. The supply from the cold reheat manifold is also taken during start-up/shut-down operation, in order to maintain the required minimum feed temperature. The deaerator spray nozzles and the nozzle strainers shall be or stainless steel. The deacration area must be lined with stainless steel. The entire vapour

extraction system must be manufactured from stainless steel. To allow for possible slopping of the contents of the feed tank, a horizontal impact force of 10% of the maximul11 vertical load l11ust be assumed. In order to avoid the danger of corrosion, diverter plates should he lilted in the dead corners of the feed tank to improve circulation. The wall thick-

284

nesses for the feed tank and deaerator shal1 have a corrosion allowance of at least 3 mm. The tank must be suitably stiffened to safely withstand Cull vacuum.

All valves and fittings directly above the feedwater tank must be accessible from platforms.

2.3.17 Piping, valves and accessories

Pipe and valve specification

The pipe systems must conform to the requirements declined in B0 "(General Technical Requirements", as a minimum requirement.

Interconnection work

Piping systems > DN 80 and > 1200C must be stress analyzed from anchor point to anchor point, regardless of battery limits or individual contracts.

2.3.18 Feedwater heaters

Installation and removal of the various items of plant must be possible without difficulty. Special provisions must be made for the withdrawal of the heater tube bundles.

The wall thickness for shells and ends shall be at least 8 mm. The heat exchanger tubes shall be scam less with an inside diameter of at least 15 mm.

An adequate number of inspection holes must be provided at particularly susceptible areas, such as the steam inlet, above the water level regulator, etc. to allow visual inspection of the internal condition of the 'heat exchangers.

The stub pipes shal1 he welded wherever possible, both internally and externally. Stiffeners with inspection holes for stub pipes should be welded in place where necessary.

LP feed water heaters

Adequate provision shall be made to protect the turbines against the backflow of water from the LP feedheaters. In the event of increased level the condensate of LP feedheaters I shall drain to the turbine condenser. If the water level rises above a certain set point, a level monitor shall close the shut-off valves in the bleed steam lines to the LP feedheaters.

Similarly, the emergency drain of the LP feedheaters and the steam side safety) valves shall be suitable for discharging the maximum rate of condensate flow according to the requirements

285

The LP feed heaters shall be of standard horizontal tube-plate type with U-tubes. A welded-on hotwell shall be provided for water level control (if required). The material of the tubes shall be of stainless steel.

All pipe collections and all connections on the vacuum side shall be welded.

Valves and other fittings exceeding nominal size of 25 mm which are continuously or intermittently under vacuum shall be provided with seal water connections.

Shell and tube bundle shall be equipped with effective baffle plates and protection at the steam and drains inlet. Particular care shall be taken for proper air extraction so that no air pockets can form inside the heat ex-changers.

HP feedwater preheaters

During low-load operation of the turbine, when the pressure in HP feedheater is no longer sufficient to drive the condensate into the feedwater tank, the drain is led to the condensate drain tank (if necessary via a flash tank) via a low-load drain control system. The automatic switchover of the drain from the feed water tank to the storage tank and vice versa should be done dependent on the pressure difference between HP heater and feed water tank considering a suitable hysteresis characteristic.

Adequate provision must be made to protect the turbine against the backflow of water from the HP feedheaters. If the water level rises exces-sively the feedwater line must be automatically by-passed and simultaneously the motorized shut-off valves and the emergency check valves in the bleed lines upstream the feedheaters are to be closed without tripping the turbine.

It must be possible to operate the feedwater bypass valves of the HP feed-heaters either manually or automatically. Automatic operation should be by means of separate level monitors in the HP feed heaters. The operation of the bypass valve shall not initiate turbine trip. In case of pipe burst in the HP heaters the 2 out of 3 high level trip shall initiate immediately the isolation of the HP heaters and bypassing the feedwater.

The safety valve to be provided on the shell side of the HP feedheaters must be capable of discharging the max. leak rates of the emergency shut off valves.

The HP feedheaters shall be designed according to ASME and shall be AS ME stamped heaters.

All connections must be welded. The feedwater tubes must be manufactured from high-strength steel. Adequate provision must be made in the design for the possible expansion of the tubes and internals under the

286

different temperature conditions. The complete tube bundle must be stress-relieved.

Effective baffle plates and protection must be incorporated in the shell and tube bundle adjacent to the steam inlet.

2.3.19 Tanks


The drain condensate tank must be dimensioned for the maximum volume of condensate arising from the atmospheric flash tank and tundish drains. The inside tank overflow line is to be so dimensioned that the maximum inflow of condensate can be discharged without the outflow velocity in the line exceeding 0.8 m/s. The tank is to be of the horizontal cylindrical type and mounted as low as possible so that an adequate head exists for all infeeds.

The condensate level in the drain tank shall be automatically maintained constant by means of control valve on the pressure side of the condensate drain pumps. A common line for tank overflow and tank draining is taken to the hot drainage system. The condensate-coming from the flash tank has to be introduced into the tank below the lowest condensate level by way of a pipe with nozzles. The pipe is to be fixed inside on the tank bottom and must have a clear discharge cross section of at least 2.5 time the pipe cross section.

Atmospheric flash tank

The atmospheric flash tank is a vertical cylindrical tank which must be so dimensioned that the steam and condensate are properly separated and can be separately discharged. The condensate will be discharged to the drain condensate tank, the steam' to the atmosphere. The condensate fed to the atmospheric drain flash tank can be run through common collecting pipes with tangential inlet into the atmospheric flash tank.

Only condensate at approximately the same temperature and pressure can be combined to a common header. the collecting pipes are not to be arranged at the same height on the tank circumference.

The collecting pipes entering the atmospheric flash tank are to be so dimensioned that the flash steam forming on inlet to the atmospheric flash tank does not exceed a velocity of 100 m/s (if necessary, throttle orifices ate to be provided in the inlet headers). The condensate is to be fed into the tank above the highest water level and the flash tank outlet is to be provided with a water trap to prevent steam from blowing through into the drain condensate tank. Between the highest point on the water trap and the steam space of the flash tank a vent line is to be provided for preventing complete emptying of the water space of the flash tank.

287

2.3.20 Drain condensate pumps

All parts of the pumps coming in contact with the water arc to be manufactured in stainless material. Casings and rotors arc to be provided with wear rings in order to permit easy replacement of the parts subject to wear. Condensate from the discharge pipe is to be used as scaling water as far as required.

In normal cases one pump will be in operation. The second pumps shall start automatically if the operating pump trips.

The pump motors arc to be so designed that even with 25% overload the pumps will not be switched off. Pumps and driving motors arc to be supplied on a common base plate.

The installation height of the pumps and the NPSH value of the pumps are to be matched to one another so that there will be sufficient suction head even under the most extreme operating conditions.

2.4 Technical Schedules

The following technical schedules comprise part of this specification. The data and requirements specified in the respective forms arc to be adhered to and the missing data of forms arc to be completely filled in. The completed technical schedules arc to be submitted with the Bid.

B2/FB Performance and Design Data

B2/FD Technical Data by Bidder

288

BPDB, Barapukuria 250 MW Power Plant Minimum Requirements

Section B2: Steam Turbine Plant


Turbine

Turbine type Reheat condensing steam turbine

Number of turbine casings - 2

Maximum Continuous Rating at generator terminals at cooling

MW 250 + 10%

water inlet temperature of 35°C (according to mean cold water temperature of cooling tower)

Permissible deviations of live steam pressure and live steam temperature

- According to IEC recommendations latest edition

Swallowing capacity at 100% live steam pressure % 104

Permissible tolerance of swallowing capacity % -0/+3

Frequency Hz 50

Permissible frequency deviations at Maximum Continuous Rating

-

• without limitations % -3 to +3

• maximum 20 minutes duration but not exceeding 2 hours per year

% -4

• maximum 10 minutes duration but not exceeding 1 hour per year

% -5

Number of pre-heating stages - minimum 6

Condenser

Cooling water temperature increase K max. 10

Maximum cooling water velocity in condenser tubes with 10% blocked tubes

m/s 2.2

Design pressure bar full vacuum

Max. cleanliness factor referred to design cooling surface % 110

Minimum cooling water velocity in condenser tubes m/s 1.5 or according to requirement of sponge ball cleaning equipment

Minimum tube bore of condenser tubes mm 17

B2/FB-1

289


Section 82: Steam Turbine Plant


Generator Rated voltage at generator terminals kV Select between

(11 - 15.75) ± 5%).

Rated frequency Hz 50

Rated power factor (lagging) cos phi 0.80

Rated power factor (leading) cos phi . 0.92

Unsaturated subtransient reactance x"d (without minus % 17 tolerance and at rated generator output)

Rated short-circuit ratio kc (without minus tolerance) - 0.50

Insulation class for generator and exciter - F

Permissible operation at MCR according to insulation class - B

1) Minimum ± 5% voltage variation range. The Bidder/Contractor may prove. if higher values are appropriate.

Generator main connections (GMC)

Rated system voltage kV 12 - 17.5

Operating voltage kV Select between11-15.75

Rated frequency Hz 50

Impulse withstand voltage (to earth) kV(peak) 75 - 95

Power frequency withstand voltage kV 50

Type of ducts - Single-phase. self-ventilated

Secondary current of current transformer A 1

Class of current transformer measuring core 0.5M5

Class of current transformer protection core - 5P20

Secondary voltage of voltage transformer V 110/ √3,110/3

Class of voltage transformer - 0.5/0.2

Earthing switch

Rated voltage kV 12 - 17.5

Impulse withstand voltage 1.2/50~s (across open contacts) kV(peak) 75.-95

Power frequency withstand voltage. 1 min (across open contacts)

kV 28 - 38

B2/FB-2

290




Combined deaerator/feedwater tank

Mode of operation of deaerator

Variable pressure with fixed minimum pressure

Design pressure 120% of respective maximum turbine bleed pressure and full vacuum

Design temperature °C' Max. turbine low load temperature

LP feedheaters

Design pressure of LP feedheaters (steam side) 120% of respective maximum turbine bleed pressure and full vacuum

Design temperature of LP feedheater (steam side)

Maximum turbine no-load temperature plus 20 K, but at least 200 °C

HP feedheaters

Design pressure of HP feedhealers (sleam side) 120% of maximum operating pressure

Design temperature of HP feed heaters (steam side)

Maximum operating temperature plus 20 K

Design pressure of HP feedhealer (water side) 120% of maximum delivery head of the feedwater pumps at minimum flow and cold conditions

Drain condensate pumps No. of pumps 2 x 100%

B2/FB-3

291

BPDB, Barapukuria 250 MW Power Plant Bidder/Contractor


Technical Data by Bidder Unit Data

Steam turbine generator

Total number of steam turbine generators -

Maximum Continuous Rating of turbine generator MW

Steam pressure at HP-turbine inlet at MCR bar

Steam temperature at HP-turbine inlet at MCR °C

Steam temperature at IP-turbine inlet at MCR °C

live steam flow at MCR of turbine generator kg Is

No-load steam consumption kg/s

Number of feedwater preheating stages -

Final feedwater temperature at MCR -

Exhaust pressure at MCR bar

Exhaust moisture %

Coupled critical speeds up to 150% of nominal speed rpm

Steam Turbine

Manufacturer -

Type -

Sectional drawing No. -

Casings

Number of casings

Casing design HP -

Casing design IP -

Casing design LP -

Rotors -

Number of turbine shafts -

Distance between bearing centres HP/IP shaft mm

LP shaft mm

B2/FD-1

292




Blading

HP regulating stage:

Type of wheel

Mean blading diameter mm

Pressure in the regulating wheel chamber at MeR bar

HP/IP blading:

Type of H.P./I.P. blading (impulse/reaction)

Number of stages

Length of blades last row mm

Mean blading diameter last row mm

LP blading:

Type of LP blading (impulse/reaction) -

Number of stages

Length of blades last row mm

Mean blading diameter last row mm

Exhaust area of last row (axially) m2

Materials

HP/IP outer casing -

HP/IP inner casing

HP/IP blade carriers

LP outer casing

LP inner casing

LP blade carriers

HP/IP rotor

LP rotor -

HPIIP nozzles -

HP/IP rotor blades -

LP nozzles -

LP rotor blades -

Casing of emergency stop valves -

(HP-steam; reheat-steam)

Casing of HP-steam governor valves -

Casing of reheat steam governor valves -

Casing of LP-steam governor valves

B2/FD-2

293




Emergency stop valves

Number of valves

•HP-steam

•reheat-steam

Turbine speeds

Rated rpm

Overs peed trip - electrical rpm - mechanical rpm

HP-steam governor valve

Number of valves

Size mm

Type

Actuator

Reheat-steam governor valve

Number of valves

Size mm

Type

Actuator

Bleed steam emergency shut-off valves Type

Manufacturer

Type

Bearings

Number of journal/thrust

bearings Type: Journal

Thrust

Maximum oil outlet temperature 0C

B2/FD-3

294




Dimensions

Total length of turbine generator m

Length of foundation m

Width of foundation m

Height of foundation m

Weights

Heaviest part to be handled by crane -

Weight of heaviest part to be handled by crane t

Weight of complete turbine generator t

Starting and loading time to MCR

• Cold start from ambient temperature

• warming-up time min.

• starting time up to nominal speed min.

• loading time up to full load min.

• Warm start after 8 hours


• starting time up to nominal speed min.

• loading time up to full load min. • Hot start after 2 hours


• starting time up to nominal speed

• loading time up to full load

min.

min.

Turning device

Method of operation

Turbine rotor speed rpm

Drive -

Rating kW

B2/FD-4

295




Gland steam condenser

Number of condensers -

Materials:

Tubes -

Shell -

Gland exhauster

Number of exhausters -

Type -

Rating kW

Oil Supply

Tank capacity m3 .

Number of recirculation (per hour) I/h

lubrication oil system pressure bar(g)

Main oil pump

Type -

Drive -

Speed rpm

Material of pump casing -

Auxiliary oil pump

Number/capacity of pumps -/%

Type -

Rating kW

Speed rpm


Emergency oil pump

Number of pumps -

Type -

B2/FD-5

296

BPDB, Barapukurla Power Plant Bidder/Contractor



Rating kW

Speed rpm


H.P. jacking oil pump

Number of pumps -

Type -

Rating kW

Speed rpm


Oil vapour extraction

Number of extraction fans -

Type -

Rating kW

Oil cooler

Number of coolers -

Capacity per cooler %

Erection (horiz.lvert.) -

Max. oil outlet temperature °C

Cooler length mm

Materials:

Tubes -

Shell -

Oil separator .

Manufacturer -

Type -

Flow rate per separator of lubrication oil flow %

Heat rating kW

Rating of drive kW

Lubrication oil filter

B2/FD-6

297




Type -

Flow rate per filter %

Grade of filtration µm

Control oil system

System pressure bar(g)

Control oil pump (where applicable)

Number of pumps -

Capacity per pump %

Type -

Rating kW

Speed rpm


Control oil filter

Type -

Flow rate per filler %

Grade of filtration µm

Condenser

Total number of condensers -

Manufacturer -

Type -

Arrangement -

Condensing Operation at MCR:

Steam flow kg/s

Cooling water flow m3/h

Cooling water temperature rise K

Cooling water pressure loss bar

Heat transfer coefficient kJ/m2sK

Fouling factor (which is considered in the cooling surface)

%

Cooling surface (outside diameter) m2

Number of flow passes -

B2/FD-7

298




Diameter of tubes (bore) mm

Wall thickness of tubes mm

length between tube plates mm

Number of tube support plates

Number and size of cooling water connections -/mm

Materials:

Tubes -

Tube plates -

Shell -

Water boxes -

- lining of water boxes -

Hotwell capacity minutes

Main condensate pumps

Number/capacity of pumps - / %

Manufacturer -

Type -

Nominal capacity m3/h

Delivery head m

Motor rating kW

Closed valve head m

Speed rpm

Type of bearings -

Material of pump casing/shaft/impeller -

Control and monitoring equipment

Electro-hydr. governor:

Manufacturer -

Designation of system -

Type or name of system -

Number of sensors in total -

Turbine protection system

Manufacturer -


B2/FD-8

299

BPDB, BarapukuriaPower Plant Bidder/Contractor



Type or name of system

Principle of monitoring (e.g. 1 out of 2, 2 out of 3. 2 out of 2 with self monitoring etc.) to be entered for:

Speed. high -

Condenser pressure, high -

Temperature of exhaust steam or bypass steam, high -

Relative expansion, high -

Shaft displacement. high -

Difference temperature of casing (diametrical clearance), high

-

Vibration. high -

Bearing metal temperature. high -

Lube oil pressure. low -

Fire protection -

Generator protection -

Lube oil tank level. low -

Vibration Measurement

Manufacturer -


Type or name of system -

Total number of shaft vibration sensors -

Total number of bearing vibration sensors -

Downtime ventilation plant

Manufacturer -

Maximum air humidity downstream the turbine %

(ref. to ambient temperature)

Method of operation -

B2/FD-9

300




Generator cooler (air to closed water system)

Manufacturer -

Number of coolers and capacity - / %

Material of tubes -

Synchronous generator

Applicable standards -

Manufacturer -

Type -

Protection class -

Generator power characteristic curve No . -

Rated generator output MVA Rated power factor lagging cos phi

Rated power factor leading cos phi

Rated active power (at rated gen. output) MW

Rated voltage kV

Voltage variation range %

Rated current (at rated gen. output) A

Rated frequency Hz

Rated speed rpm

Direct axis sub-transient reactance saturated x"d (unsaturated, minimum value)

%

Maximum asym. three-phase short-circuit current kA (peak)

(at rated gen. output)

Short circuit ratio kc -

Interia constant (H) of the stem-turbine-plus-generator-set (at rated gen. output)

kWs/ KVA

Test voltage of stator winding kV

Test voltage of rotor winding kV

B2/FD-10

301




Stator Number of bushings - Type of winding - Insulation Class - Type of insulation - Rotor Diameter of rotor body mm Length between bearing centers m Type of windings - Type of damper winding - Insulation class - Type of insulation - Shut down heating Rated power kw Rated voltage V Excitation System Type of excitation system (short description) - At no load: Exciter current A Exciter voltage V At rated generator output: Exciter current A Exciter voltage V Exciter machine Manufacturer - Type - Power Input KW Insulation class - Voltage regulator Manufacturer - Type -

Voltage regulation range ± %

Generator dimensions Total length m

Total height m

Total width m Generator weights

Stator weight t Rotor weight t Transport weight complete generator t

Heaviest part and its weight to be lifted during maintenance in machine hall

-/t

B2/FD-11

302


Section B2: Steam Turbine Plant Unit Data

Technical Data by Bidder Synchronizing equipment

Manufacturer - Type - Power supply voltage Input V

Input range from - to V

Frequency range from - to Hz

Adjustable circuit breaker closing time, from to msec

Max. permissible angle between generator and grid voltage

0El

Digital generator protection system

Manufacturer of protection system -

Number of cabinets -

Auxiliary voltage V

Auxiliary voltage range ±%

Protection system testing device

Type -

Generator main connections Manufacturer - Type of ducts (short description) -

Rated system voltage kV

Rated frequency Hz

Rated current A

Impulse withstand voltage (to earth) kV(peak)

Power frequency withstand voltage kV

Max. asymmetric three-phase short-circuit withstand current

kA(peak)

Rated short-time withstand current (3 sec.) kA

B2/FD-12

303




Current and voltage transformer

Secondary current of current transformers A

Accuracy class: measuring -

metering -

protection

Secondary voltage of voltage transformers V

Accuracy class: measuring -

metering

protection

voltage regulation

Earthing switch

Manufacturer -

Type of earthing switch -

Rated voltage kV

Rated frequency Hz

Rated current A

Rated short circuit making current kA(peak)

Rated short time withstand current (3 sec.) kA

Power frequency withstand voltage kV .

Rated impulse withstand voltage kV(peak)

Rotor driven earthing switch yes/no

Protective capacitors

Type

Number of capacitors Nos.

Rated voltage kV

Rated frequency Hz

Rated capacity nF

Enclosure of steam turbine generator

Type

Manufacturer

Max. noise pressure level at 1 m distance dB(A)

B2/FD-13

304




HP-steam bypass station

Number -

Capacity of steam t/h/%

IP-steam bypass station

Number -

Capacity of steam t/h/%

Feedwater pump

Number of pumps /each pump capacity -/% Manufacturer - Type - Minimum capacity m3/h

No. of stages - Type of journal bearings - Method of axial thrust hydraulic compensation - Type of axial bearings - Type of bearing lubrication -

Oil supply from -

Type of glands or seals - Closed valve head m Materials:

Pump casing - Shaft - Impeller

Total power requirement of feed pump sets when the turbine is running at MCR

kW

FWP Hydro coupler manufacturer VOITH,

Germany One pump set in single operation (at max. speed):

Delivery rate HP/IP m3/h/m3/h

Delivery head HP/IP m/m

Net position suction head required m

Power requirement of one pump set at motor terminals kW

305

B2/FD-14

B2/FD-15




Pump efficiency at rated capacity % ..

Coupling

Type -

Maximum allowable transmitted load kw

Booster pump (if applicable)

Number of pumps -

Manufacturer -

Type -

Type of journal bearings -

Type of thrust bearings -

Type of bearing lubrication -

Oil supply from -

Type of glands or seals -

Materials:

Pump casing -

Shaft -

Impeller -

One pump in single operation (at max. speed):

Delivery rate m3/h

Delivery head . m

Power requirement of one pump set at motor terminals kw Coupling

Type

Maximum allowable transmitted load kw

306




Feedwater pump motor

Manufacturer -

Type -

Rated power kW

Rated voltage kV

Rated speed rpm

Rated efficiency %

Rated power factor -

Starting time sec.

Protection system -

Insulation class -

Type of bearings -

Type of lubrication -

Method of cooling the motor -

(external fan/internal fan/water-cooled)

Deaerator for feedwater system

Manufacturer -

Type -

Mode of operation -

Maximum outnow rate of deaerator kg/s

Outside diameter (where applicable) mm

Total length (where applicable) mm

Materials

Shell (where applicable) -

Internals -

B2/FD-16

307



Technical Data by Bidder Unit Data:

Feedwater tank

Manufacturer -

Nominal capacity m3

Normal working capacity m3

Outside diameter mm

Total length mm

Materials:

Shell -

Internals -

Operating weight kg

Weight during testing kg

Water pressure loss at inlet (MCR) bar

Design temperature deaerator °C

Design pressure deaerator bar

High pressure feedheater 1

(Design data at MCR of turbine unit) - Manufacturer - Type -

Heat rate kJ/s

Heat transfer coefficient (outside diameter) condensation/drain kJ/m2sK

Terminal temperature difference

Steam side K

Drain side K

Total heat exchanging surface (outside diameter) m2

- Shell outside diameter mm

Total length mm

Tube outside diameter mm

Tube wall thickness - mm

Materials:

Tubes - .

Tube plate - Shell - Weight kg

B2/FD-17

308




High pressure feedheater 2

(Design data at MCR of turbine unit) -

Manufacturer -

Type -

Heat rate kJ/s Heat transfer coefficient (outside diameter) condensation/drain kJ/m2sK Terminal temperature difference

Steam side K

Drain side K Total heat exchanging surface (outside diameter) m2

Shell outside diameter mm Total length mm Tube outside diameter mm Tube wall thickness mm Materials: Tubes - Tube plate - Shell -

Weight kg

Low pressure feed heater 4

(Design data at MCR of power unit) -

Manufacturer -

Type -

Heat rate kJ/s

Heat transfer coefficient (outside diameter) condensation / drain kJ/m2sK


Steam side K

Drain side K


Shell outside diameter mm

Total length mm


Tube wall thickness mm

Materials:

Tubes -

Tube plate -

Shell -

Weight kg B2/FD-18

309

BPDB, Barapukuria 250 MW Power Plant Bidder/ Contractor



Low pressure feedheater 5


Manufacturer -

Type

Heat rate kJ/s

Heat transfer coefficient (outside diameter) condensation/drain kJ/m2sK

Terminal temperature difference Steam side ..

K

Drain side K



Total length mm



Materials:

Tubes -

Tube plate -

Shell -

Weight kg

Low pressure feed heater 6


Manufacturer -

Type -

Heat rate kJ/s

Heat transfer coefficient (outside diameter) condensation /drain kJ/m2sK


Steam side K

Drain side K



Total length mm



Materials:

Tubes -

Tube plate - B2/FD-19

310




Shell -

Weight kg

(Technical data for further feed heaters to be filled in as required above)

Atmospheric flash tanks

Number of tanks for each boiler and turbine unit -

Cold condensate tank


Net capacity of each tank m3



Installation level -

Drain condensate pumps

Number of pumps for each drain condensate tank -

Capacity of pumps %

Manufacturer of pumps -

Electrical motor rating kW

B2/FD-20

311

Coal Handling System

312

B3. Coal Handling System

3.1 General

Existing coal handling system capacity is 300 MT/ hr which is being used for existing 2 x 125 MWe units.

Existing Coal handling system is receiving coal from the adjacent coal mine mouth with storage arrangement in the Power Plant coal yard, transportation and storage in coal bunkers.

The raw coal from the coal mine to the coal storage area is transported by a single line conveyor belt system. For the transportation of the crushed coal from the coal storage area up to the coal bunkers of existing 2 x 125 MWe units, a double line belt conveyor system is being used.

A ‘Coal Processing Plant’ to remove iron, hard materials, waste & large size coal and to control moisture of coal (within the limit of 10%) shall be provided at the upstream of existing ‘Magnetic Separator’ with necessary modification of relevant coal conveyer system.

A single line coal conveyor belt system with two (02) crusher units shall be provided from the upstream of existing crusher unit to the new coal yard with necessary modification of relevant coal conveyer system.

A coal conveyor belt system shall be provided in between new coal yard and old coal yard.

Extension of existing two coal supply belt conveyors shall be provided from existing unit no. 2 to the new 250 MW unit complete in all respect to feed coal to the coal bunkers of the 250 MW unit.


3.2.1 Coal handling system


• a ‘Coal Processing Plant’ at the upstream of existing ‘Magnetic Separator’ with necessary modification of relevant coal conveyer system. Coal Processing Plant shall comprise the following but not limited to: • Raw coal entry selection belt conveyor • Power double sides plough discharger • Circular vibration screen • Large size waste belt conveyor • Raw coal transfer belt conveyor • Raw coal upper bunker transfer belt conveyor corridor • Hanging ever-magnet iron remover

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• Dryer • Processed coal weighing belt scale etc.

• belt conveyor up to the new coal crusher

• two coal crusher complete with feed hopper, electric drive, necessary supports, explosion and fire protection measure, dust proof housing, classifier, inertisation devices, screening system

• traversing and reversible distribution belt conveyors for coal transportation from the crusher to the new coal storage area (open and covered storage area)

• extension of existing two coal supply belt conveyors from existing unit no. 2 to the new 250 MW unit complete in all respect to feed coal to the coal bunkers of the 250 MW unit

• ventilation and dust collecting equipment for all transfer points

• steel structure, stairs, ladders, walkways, conveyor bridges, necessary supports, discharge hoods

• all associated equipment such as belt drives, idlers, pulley, belt and pulley scrapers, hold barks

• auxiliary equipment such as belt weighing scale, coal sampling devices, all necessary belt safety and protection devices

• washdown system to clean the conveyor systems and walkways

• weighing facilities (belt scale)

• dust extraction and suppression system including water spray system, piping, valves, etc.

• passive safety measure to protect the stored crushed coal against self-ignition

• coal bunker ventilation system

• scaling system

• PLC safety interlocking system


3.3.1 General

The following factors shall be taken into account on system design and equipment selection:

• safety • reliability • maintainability • minimize indoor and outdoor environmental pollution • standardization of components.

The scope of design and supply of coal handling system include all the

314

processes and facilities as mentioned.

The length of the coal conveyor system which has to be provided to transport the coal from the upstream of existing crusher unit to new coal storage area is approximately 60 meter and the length of the coal conveyor system from new coal storage area to old coal storage area is 50 meter.

3.3.2 Belt conveyors

Wherever applicable, the belt conveyors shall be lodged in closed conveyor bridges.

An unilateral walkway with open grid flooring shall be provided parallel to all conveyors. Idler sets shall be provided with labyrinth seals and shall run true. Bearings shall be of the "maintenance free type", i.e. lubrication shall be required not more frequent than once per year.

Drive pulleys, tail and take-up pulleys shall be of closed design.

Pedestal bearing shall be provided with labyrinth seals.

Belt scrappers shall be arranged at the discharge pulley and, if necessary, for tail pulleys.

Material and construction of covering plates between upper and lower discharge hoods and product guides shall be chosen in view of optimum sliding behaviour of the product, avoidance of clogging and limitation of noise. Material shall be stainless steel, reinforced fibre glass or equivalent. Rubber aprons for guidance shall be provided.

Gears shall be of the slip-on type. Flexible or hydraulic start-up couplings (depending on size and requirements) shall be used.

In order to reduce the volume of spare parts, the number of different types for driving units shall be kept to a minimum.

Retention assemblies such as limit switches, true-run switches, belt monitors, lanyard switches shall form part of the mechanical equipment of the conveyor plant.

For conveyors of short length, fixed installed tension devices may be used, while for conveyors of longer length tension carriages or equivalent self regulating tension devices to be used.

Junction towers shall consist of steel frame work and outside cladding. Intermediate stairs and steps shall be provided with grid floorings.

Above the conveyor heads or take-up stations respectively trolley beams for a payload of 3 tons shall be provided.

315

Distribution of coal to the individual coal bunkers shall be done preferably by a horizontal tripper conveying system. It remains at the latitude of the Contractor if the tripper conveyors will be provided with carriages, movable on rails or whether one reversible conveyor will be attributed to each pair of bunkers. Special care shall be given to the selection of the sealing system "bunker-tripper conveyor".

3.3.3 Magnetic separator and tramp iron detectors

One inline magnetic separator in conjunction with two tramp iron detectors shall be installed in the conveyors feeding to the coal crusher. One of the tramp iron detectors shall be installed upstream of the magnetic separator and shall activate the magnet, while the other one shall be installed downstream of the magnetic separator and shall stop the conveyor system in case that iron is detected.

The magnetic separator shall use an electric magnet and shall be provided with its own rectifier.

A magnetic separator of the "belt drum" type may be used.

Removal of tramp iron may be made manually by using a trolley. This trolley shall be supplied with the system.

3.3.4 Weighing facilities (belt scale)

The belt scale of the electronical type shall be integrated in the conveyor system leading to the boiler.

The scale shall have an accuracy of not less than ± 1%.

Indication of instantaneous conveyance, totalizing and tripping shall be recorded.

3.3.5 Reclaiming system

The raw coal shall be handled by conveyor to the crusher/screen house. The crushed coal shall be conveyed directly to the boiler coal bunkers. In the case coal is not needed in the boiler coal bunkers the crushed coal shall be sent to coal storage areas. The transfer of the crushed coal to the coal storage area and the distribution shall be done by traversing and reversible belt conveyors. Crushed coal storage area shall have a capacity of 8 days plant - MCR requirement considering the worst coal involved. The coal storage area will be operated only in emergency when coal is not received from mines.

Suitable traveling type of stacker shall be provided to stack the crushed coal to a height relevant to the availability of space. Necessary platform with drainage facility shall be considered. Soil improvement to improve bearing strength and other requirement shall be considered as required. Reclaim from both coal storage areas (covered and open storage area) shall be

316

done by front end loaders and loaded to underground hoppers for further feeding to downstream conveyors of inplant coal handling. Required number of front end loaders shall also be supplied. Number of front end loaders shall be adequate to feed the conveyors at 110% MCR of boilers.

The inplant conveyors capacity shall be adequate to fill the boiler bunker in 8 hours operation.

The coal storage areas shall be provided with necessary fire water system and compacting/dust suppression system.

Covered storage to cater to about 4 days MCR requirement shall be provided as part of the total coal storage area. The covered storage shall be constructed with structural steel supports and metallic sheet covering. Size and arrangement of the covered storage shall be such that it shall not hamper stacker movement/operation.

3.3.6 Crushing and screening system

Coal received shall be screened and crushed to the required size of the mill system in the crusher prior to sending to boiler bunkers.

Adequately sized surge hopper, with feeder chutes/flap gates, shall be provided to have maximum flexibility in the flow of coal.

Two crushers shall be provided (one as standby).

Crushers shall be of suitable heavy duty impact type. Crusher and screens shall be supported suitable and isolated from other foundation work. Necessary antivibration dampers shall be provided for crushers and screen foundations.

Screens shall be provided to screen the fines in the coal in order to minimize loading of crusher. The screening and crushing system shall be designed for 2 x 100% to meet the requirement and retain flexibility in operation. Screens shall be of heavy duty rotary screen or electromechanical screen with unbalanced motor. The capacity of the screens and crushers shall be suitable for adequate recirculation design margin.

The screened coal shall be sent to boiler coal bunkers directly.

3.3.7 Bunker feeding system

The capacity of the conveyors system up to bunker feeding conveyors shall be adequate to meet one day's requirement in two shifts of 8 hours operation. Samplers and belt weigh scale shall be provided prior to bunker feeding conveyor with the necessary controls.

Bunker filling shall be done by a traveling tripper conveyor arrangement. The bunker floor shall be sealed to have effective ventilation system and

317

tripper arrangement shall be given for bunker filling. This system shall also include bunker sealing arrangement, bunker ventilation system and traveling tripper conveyor.

Necessary bunker flooring shall also be included.

3.3.8 Dust extraction/dust suppression/ventilation system

Dust extraction system shall be provided in all the junction towers and crusher house to minimize the air pollution problem. Process water shall be used for dust suppression system. I

Dust suppression system shall also be provided to the coal storage area. Necessary spray system and arrangement shall be provided in both coal storage areas.

Bunker ventilation shall be provided to extract the dust due to bunker filling operation.

The system shall be designed for air quality in which respirable particulate matter shall not exceed 0.5 mg/m3.

3.3.9 Safety interlocking system

A PC based PLC safety interlocking system for coal handling system shall be such that sequential starting/shut-down of all the equipment due to trip condition of downstream conveying equipment is ensured. The trip-off of the minimum equipment in the safest sequence during abnormal operating conditions shall be ensured. The functions of safety interlocking system is as follows:

• annunciate/indicate initiating cause for the equipment which has tripped • prevent restarting of equipment until safe conditions are restored • retain flexibility of operation as is consistent with safety • the interlocks provided shall permit one stream operation retaining the

flexibility in operation.

3.3.10 Control room

The inplant coal handling system starting from the crusher up to boiler bunker feeding trippers operation shall be controlled from inplant coal handling control room located in the Plant near to crusher house. Other equipment/components shall be operated from local stations (see also Chapter 9).

318

BPDB, Barapukuria Power Plant Minimum Requirements

Section B3: Coal Handling System


Coal handling system

Bulk density to be considered for capacity calculation kg/m3 0.65

Bulk density for calc. power of drive kg/m3 1.0

Safety factor for design of conveying elements and conveying equipment

1.1

Safety factor for capacity selection of storage equipment 1.0

Capacity of belt conveyors to bunkers shall permit the transport of the daily (or hours) coal demand to the bunkers within

hours 4

Max. velocity of belt conveyors m/s 2.0

Number of streams and capacity for related equipment:

• elevated coal belt conveyor (if required) 1 x 100%

• ground level bell conveyor 1 x 100%

• traversing and reversible distribution belt conveyor 1 x 100%

• coal crusher 2 x 100%

• extension of bunker tripping conveyor 2 x 100%

• magnetic separator 1 x 100%

• belt scale 1 x 100%

• tram iron detectors 2 x 100%

Separating degree of separator (filler), dust suppression (particulate matter)

mg/m3 0.5

"

B3/FB-1

319



Technical Data by Bidder/Contractor Unit Data

Coal handling equipment

Belt conveyors

Type -

Manufacturer -

Belt widlh mm

Height of borders mm

Handling capacity kg/h

Belt velocity m/s

Material of belt -

Drive power kW

Coal crusher

Number pcs

Manufacturer -

Type -

Capacity t/h

Screen dimension mm

Final grain size mm

Motors:

• manufacturer -

• type -

• rating kW

• rated voltage kV

• speed rpm

Magnetic separator and tramp Iron detectors

Type/ Manufacturer -

Number' pcs

Location -

Rated power kW

B3/FD-1

320




Weighing scale

Type -

Manufacturer -

Capacity kg

Accuracy %

location -

Tripper conveyor -

Manufacturer -


Number pcs

length m

Capacity kg/h

Width mm

Belt velocity m/s

Coal bulk density kg/m3

B3/FD-2

321

Air and Flue Gas System

322

Table of Contents B4. Air and Flue Gas System

4.1 General

4.2 Scope of Supply and services 4.2.1 Air Supply Systems 4.2.2 Flue Gas System 4.2.3 Electrostatic Precipitator 4.3 Special Technical Requirements 4.3.1 General 4.3.2 Air and flue gas ducts and dampers 4.3.3 FD fans and ID fans 4.3.4 Steam air preheaters 4.3.5 Regenerative air preheater (AH) 4.3.6 Flue Gas recirculation fans (if required) 4.3.7 Electrostatic Precipitators (ESP)

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B4. Air and Flue Gas System 4.1 General

The air supply and flue gas system shall be designed in a double flow path. Each of the components shall be provided twice. In case of failure of any equipment within the air and flue gas system the steam generator shall be still able to obtain 60% of its MCR. Dampers in the air and flue gas ducts shall consider a cross over operation (e.g. operation forced draught fan left side. regenerative air heater right side)

Provision for flue gas recirculation system for decreasing the NOx emission has to be provided, if necessary.


4.2.1 Air supply systems


� 2 (two) complete FD fans with electric motor, forced lubrication system

• air ducts with reinforcement and support structure comprising • the FD fan and mill primary air fan inlet ducts • the FD fan and mill primary air ducts between the air fans and the

regenerative air preheaters

� hot air ducts to mills' and burners � 2 (two) cooling air fans with electric motors � 2 (two) steam-heated air preheaters with condensate drain control

system

• 2 (two) regenerative type air preheaters including rotor with motor, gearing, automatic sootblowing equipment, washing device. reserve drive, rotation monitoring as well as fire alarm device, an extinguishing and rinsing device with additional washing and rinsing drive

• all necessary isolating and regulation dampers with electric actuators, expansion joints and Venturi measurement devices

� insulation including cladding

• all measures necessary for damping out vibration and for noise attenuation including silencer.

4.2.2 Flue gas system


• Flue gas ducts with reinforcements and support structure. isolating and regulations dampers with electric actuators expansion joints, Venturi measurements devices, etc. consisting of raw gas duct with ash hopper between the steam generator outlet and the regenerative air preheater

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inlet duct, from the regenerative air preheater exit to the inlet hood of the electrostatic precipitator (ESP), clean gas duct from the exit hood of the ESP to the induced draft fan (ID fan), common duct between ID fans and further to the stack inlet

• 2 (two) ID fans (with special type impeller blade considering 100% ash with flue gas causing no damage or unbalance) including electric motor, forced lubrication system

• 2 (two) flue gas recirculation fans including electric motor arrangements for minimizing NOx formation, if necessary

• all necessary isolating dampers (for all ID fan, Coal mill, ESP, flue gas recirculation fans for plant running maintenance) and regulation dampers with electric actuators. expansions joints

• insulation including cladding

• all measures necessary for damping out vibrations and for noise attenuation including silencers.

4.3 Electrostatic precipitator (ESP)


• steel supporting structure • gas tight steel casing • hoppers and chutes including spray electrodes. rapping equipment

including motors • electrical equipment • control system with cubicles, analog and binary equipment • walkways, ladders. stairs • heat insulation • electric tracing for all ash hoppers.


4.3.1 General

The air flue gas system shall be of the balanced draft type and designed in two parallel lines. The system shall be completely gas tight.

All the equipment shall be of the high efficiency aerodynamic design silent in operation vibration free and must guarantee complete safety in service. All fans shall be dynamically balanced in the factory.

The flues and ducts shall be adequately supported and shall be provided with necessary inspection access, observation and cleaning doors shall, be provided to give access to flues and ducts for inspection and maintenance. These doors shall be gas tight under all working conditions.' Each inspection door has to be equipped with one small observation flap which can be opened and closed without

325

any tool. The inspection doors have to be provided for inspection of each heating surface at flue gas inlet and outlet.

All necessary gas flues and air ducts shall be provided including auxiliary plant. Wherever necessary, balance ducts fitted with isolating dampers shall be provided. It shall be so arranged to maintain an even draught across the width of the boiler unit at the exit from the boiler.

All flues and ducts shall be designed to give an equal distribution of gas and air flow to the various portions of the units and freedom from pulsation, vibration and noise.

Wherever necessary, a series of sampling, measuring and test points shall be arranged in the flue and duct in approved positions. means shall be provided for measuring the total combustion air flow.

4.3.2 Air and flue gas ducts and dampers

The expansion joints shall be of steel and suitable insulated. Such joints shall incorporate internal plates to prevent deposition in the joints.

Air ducts and gas flues shall be of all-welded construction of steel plates suitable stiffened by means of angles, tees or flats secured to the outside. Circular air ducts are preferable.

Ductwork shall be fabricated in sections with flanged ends so that field erection will require either the end matching and securing of connecting flanges attached to the adjacent units or welding of the adjacent flanges.

One (1) Venture throat shall be installed for measuring the air flow of air heaters primary and secondary air pulverizers hot and cold air and burners,

Suitable connection shall be provided for permanent instruments and for check and test purposes. for pressure readings all flue gas sampling, All ducts shall he designed to minimize resistance to air and gas flow and to give good distribution or gas and air flow.

The secondary air dampers of the burner must permit the exact proportioning of the combustion air to each burner which has to be proved during commissioning tests.

All necessary isolating and control dampers shall be provided lor the reliable and convenient operation of boiler unit .

Dampers shall be provided to meet the following operating conditions:

• isolation of the steam generator against heat losses when out of

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operation with one FD fan etc. and reverse

• operation with two (2) regenerative air heaters but one (I) FD fan respectively one (1) ID fan

• to take each burner group into and out of operation

• to control the combustion air flow of each single burner.

Dampers to be used for these operation procedures shall be equipped with electric drives and approved limit switches. The remote control and interlock system will be supplied under Chapter B9 of this specification.

Dampers must be capable of opera\ion under the maximum differential pressure without binding or seizure, and shall be fitted with locking devices in the fully open and shut positions.

Except where otherwise agreed, dampers shall be of the multi-leaf type and mounted in frames, and, wherever possible/shall be arranged with horizontal spindles. Dampers in flue gas ducts shall be designed and located so that the build-up of ash behind the damper blade is reduced to a minimum and their opened and closed position has to be used for the FD fan and boiler interlocking.

The damper spindles shall be of steel which is sufficient resistant and special attention shall be given to the design of the dampers. spindles and hearings to protect them against the ingress of dust/ash and distortion or deterioration due to high temperature. The bearings of the dampers shall be located outside and shall he or the self-lubricating type.

Special attention shall be given to the sealing arrangements or isolating dampers to ensure gas and air tightness when in the shut position.

Each damper shall be equipped with a local indicator and an easy unmistakable notch on both shaft ends.

Tapping holes suitably and correctly located for its purpose shall be provided for permanent instruments and for checking and testing purposes for pressure readings and flue gas sampling. All ducts shall be designed to minimize resistance to air and gas !low and to give good distribution of air flow particularly to boiler sides and the burner air registers or to the burner wind box.

The air or flue gas leakage of the dampers when closed shall not exceed 1 % of the maximum flow.

All flue gas dampers which are installed for isolation of components during operation of the unit shall be provided double. When closed. sealing air shall be supplied between the dampers.

Both regenerative air preheaters shall be provided with one common bypass on flue gas side so that during cold start-up operation without any

327

regenerative air preheater will be possible. The flue gas damper in the bypass shall be suitably interlocked to avoid that the maximum permissible temperature of stack will be exceeded.

Due attention shall be paid for the material selection of the flue gas duct in which during continuous operation the flue gas will be stagnant.

Selection of ducts and dampers within the air and flue gas system shall be done so that the wet washing of one regenerative air preheater will be possible. while the boiler will operate on partial load with the other air preheater in operation. Nevertheless the Contractor has to guarantee continuous operation of the regenerative air pre heaters without wet cleaning for the duration stated under "Guarantees" (Guarantee data sheets BO/FG).

In general, the air and flue gas ducts shall be interconnected by welding. Only in places where maintenance or repair is required (dampers, expansion joints, fans, etc.). flanged connections may be provided.

Air boxes for burners shall be designed so that at least each row will be fed separately.

Connection between boxes for burners and the membrane wall shall be done by steel expansion joints.

All ducts which are not insulated shall be suitably cleaned and painted for resistance to corrosion. ducts and flues requiring thermal insulation shall comply with the requirements of this specification.

328

4.3.3 FD fans and ID fans

Two (2) FD fans of radial type with backward curved blades shall be supplied. Each fan shall be designed for a combustion air !low which corresponds to 60% of MCR when operating with design coal and 20% excess air at furnace outlet. Furthermore, the design of the FD fans shall allow a margin for fouling of heating surface. The design of the ID fans shall consider a rise of flue gas temperature and of flow resistance due to fouling of heating surfaces.

Load operation between .30% and 60% MCR shall he possible with just one FD fan, one air preheater and one ID fan.

The FD fan shall be capable of drawing the combustion air in partially or completely from outside.

The control of the fans shall be done by inlet guide vane controllers (swirl controllers).

The fan casing shall be of approved type and so arranged that a section of the upper half is easily removable to facilitate the removal of the fan impeller without extensive dismantling of connecting flues and ducts. The casings shall be constructed of steel plates with adequate stiffening to prevent breaking or vibration.

The casing shall be securely braced with structural shapes and all seams continuously welded. The inlet sections shall be fitted with inlet cones which also form inlet seals with the fan impeller. The fan shall be supported on foot angles welded to the extended sides of the casing. A casing drain not less than DN 50 shall be provided.

All fans shall be suitable for all-weather outdoor operation.

All fans shall be driven directly by a constant speed electrical motor. Fan and motor shall be anchored on a common foundation of concrete with vibration dampers, anchoring plans with foundation loads to be supplied by the Contractor.

The motors shall be designed for operation of the fans also at a minimum air and gas temperature without exceeding the rated horse power.

The material for the shaft shall be thermally stabilized prior to final machinery.

The shaft forged and machined from mild steel or high tensile steel shall be designed to have its first critical speed not less than 125% of rated speed. The impeller shall be statically and dynamically balanced before shipment commissioning.

If as a result of electrical black-out there is a total failure of the

329

cooling water supply, the bearings must be capable of performing without cooling and be safeguarded against over-temperature.

The sealings shall be preferably of the labyrinth type.

Cooling and heating equipment has to be provided.

All platforms shall be provided to all components of the fan and motor subject of maintenance.

White metal bearing with forced lubrication shall be provided. The lubricating system consisting of oil receiver oil heater oil pumps, oil coolers shall be dimensioned to incorporate the lubrication of the fan motor too. One complete lubrication unit shall be attributed to each fan.

For fans operating with flue gas, measures shall be taken to reduce the fans wear because of dust and fly ash to a minimum.

Inlet and/or outlet silencers shall be provided in order not to exceed the specified noise level. The silencers shall be of the clement type so that it will be possible to exchange the individual silencer elements. The filling c1cments shall consist of noncombustible. heat resistant damp-proof material.

Fans of smaller capacity (shaft power less than 50 kW) may be provided with roller bearings and control by throttling will be acceptable.

The fan casings shall be insulated against heat and noises. The insulation shall be divided into pre-fabricated sections which can be easily moved, and comply with the specification of Chapter B06. Silencers are to be provided on the suction and discharge side.

4.3.4 Steam air preheaters

To ensure that the boiler exhaust gas temperature docs not fall short the dew point the primary and secondary air shall be preheated by steam air preheaters.

The steam heated air heaters shall be arranged in each air duct between FD fan and the regenerative air preheater.

The tube ends shall be welded into mild steel tube plates and the element supporting framework and headers shall be of all-welded construction. The position or the steam air preheater shall allow for the complete draining of all pressure parts.

The heating surface shall consist of finned tube elements which shall be hot dip galvanized after assembling. Aluminum fins are not acceptable.

330

The air heater shall be equipped with a 100% bypass at the air side.

Condensate shall be led back to an appropriate point in the feedwater\ condensate system through a trap and a control tank. All steam and drain piping control and isolating valves. and all other fittings shall be provided in order to satisfy the above requirements.

Drain condensate pumps of the vertical barrel type shall be provided.

Heating coils shall be easily removable for cleaning and maintenance.

The steam supply can be taken from suitable bleed points on the turbine (see Heat Balance Diagram). During start-up the steam can be taken from the auxiliary steam line. The condensate shall be cooled in a cooling stage at the air inlet to at least 80°C when working at MCR.

Drain connections (blind flanges or screwed plugs) shall also be up-stream and down-stream of the steam air preheater in the bottom of the air duct (not only in the steam air preheater frame).

Condensate pipes shall be valved so that the condensate can be returned to the unit from which the steam is coming from.

The air temperature control shall be performed by means of steam now control. located at the inlet of the steam air preheater.

4.3.5 Regenerative air preheater (AH)

Two (2) AHs shall be provided. They shall be designed to cool down the flue gases to 150°C when operating with coal at MCR with the designed excess air at furnace outlet of 20%. This design condition shall take into consideratiol1 the leakage of combustion air in the AH after an operating period of at 'least 1000 hours without adjustment of the sealing elements. The design air inlet temperature when burning coal shall be at least 80°C. However, the Contractor shall take into consideration the sulphur content of coal to avoid corrosion in the AH.

All provision shall be made to keep the amount of leakage air to a minimum. The total air leakage of a freshly adjusted AH shall result in a C02 drop of not more than 1.0 between 60% and 100% MCR.

The AH shall be designed to operate normally in parallel, but if one AH is out of operation, the other one shall be able to keep the steam generator at 60% of MCR. The sections for the primary air and secondary air shall he apportioned in accordance with the primary air/secondary air flow ratio for the design point.

The AH shall be supplied with vertical shafts, including elements. casing, sootblowers, element supports. external supports. driving gears and driving units, forced lubrication equipment together with

331

coolers and all other equipment required for the safe and efficient operation of the Plant. .

The heating elements shall consist of low alloy steel sheets of not less than 0.5 mm thickness and shall be properly packed in baskets.

The heating elements shall be spaced and compactly arranged within sectors of the cylindrical housing, but they shall be kept at a fixed distance from each other. The individual elements shall be partly or entirely corrugated or modulated to give a turbulent flow of the gases and air.

The hot and cold end elements shall be arranged in casings with removable compartments and the design shall allow for the removal of the cold and hot end element baskets through access doors provided in the AH housings.

At least 300 mm in height of the cold heating elements shall be enamelled in order to achieve longer service life. The cold end elements shall. be properly packed in baskets and a sufficient number of access door provided for easy and fast replacement. The Tendered shall give full particulars of the material and estimated performance of the intermediate and low temperature sections and the frequency of material replacement. Electrical hoist with runways etc. for maintenance and replacement shall be provided.

Each AH has to be equipped with two drives. The main drive is to be an electric motor through a gearbox or a hydraulic motor. A standby motor drive to the same gearbox or hydraulic motor shall be provided. The drive is to be complete with a self contained lubricating system which shall include a water cooling system facilities for manual rotation and rotation monitor of signal that the AH is in operation shall be provided.

For on-load cleaning integral steam soot blowers for cold and hot side shall be arranged. The blowing pressure shall be designed with respect to the thickness of the heating elements. The Contractor shall take the steam for soot blowing from a source within his limits of supply. Steam blowing equipment. bearings and other parts which so require. shall be air sealed to avoid infiltration of corrosive flue gases.

The sootblowing device has to be designed for the most effective cleaning of the AH heating surfaces.

The AH shall be equipped with fire extinguishing devices including fire alarm equipment display panel. The AH elements shall- be arranged for water washing and all necessary washing equipment shall be supplied.

The necessary drainage troughs hoppers, pipes, valves shall be

332

supplied.

Adequate sealed and illuminated inspection windows for inspection during operation and removable door and access ways for maintenance and repair shall be provided.

If as a result of electrical black-out there is a total failure of the cooling water supply. the bearings must be capable of performing without cooling and be safeguarded against over-temperature. An oil bearing temperature measuring equipment shall be supplied to judge the oil temperature.

Possibility of hot end and intermediate AH element inspection and replacement shall be provided (openings with removable covers in the ducts above the air heaters. internal beams or hooks for lifting the elements).

External hoist with trolleys and beams to extract the elements or sufficient length, electrically operated, shall be provided.

Initial thickness measurement of cold end elements has to be carried out as spot-checks before commissioning that corrosion resistance can be proved after 6.000 operation hours by measuring the sheet thickness again for operational informal ion.

The seals between the primary and the secondary portion shall be designed like those between the secondary portion and the flue gas ducts. i.e. with moveable. multi-part, radial sector plates, capable of following automatically the rotor deformation as well as with shell seals likewise moveable. Both. the radial and the shell seals shall be readjustable from outside during operation.

Ten (10) thermocouples up to a local control box shall be supplied for each AH to judge the cold end element temperature to avoid cold end corrosion .

The external surfaces shall he insulated in accordance with the requirements of this specification (see Chapter B06).

4.3.6 Flue gas recirculation fans (if necessary)

In addition to the general requirements for fans stated before the selection of flue gas recirculation fans shall comply with the following:

In order to prevent corrosion during standstill. the flue gas recirculation fans shall be provided with turning gears.

The recirculation fans shall be interlocked and protected against back reverse rotation or loss of differential pressure between fan outlet and supply point to boiler .

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4.3.7 Electrostatic precipitators (ESP)

Two ESPs shall be provided for each steam generator. Each ESP shall be designed for the maximum flue gas flow with at least 40% excess air in the furnace (ESP capacity= 140% MCR) and a flue gas temperature of 180°C (in case of AH stop 350°C for 10 min.).

The dust burden of the flue gas entering the ESP shall be determined by the Contractor.

The ESPs should be arranged behind the AH and before lD fans.

The ESP minimum requirements are:

• fields with gas tight casing • electric heated hoppers with sufficient steep hopper slope to

avoid ash bridging • and sufficient volume • access doors platforms. stairs and inside gangways and ladders • complete ESP internals and rapping devices • supporting structure • thermal insulation • paintings

Electrical part:

• transformer rectifier unit with spark control • control panel • discharge electrode supports and rapper insulator • penetrating insulator • insulator heater • portable grounding rod • ESP control centre for enclosed cubicle (indoor use) • all motors .

The spraying electrode shall be made of material that can resist tension crack corrosion.

The use of wire-type spraying electrodes is not permitted.

Each ESP shall consist of a single steel casing with sufficient equal mechanical and electrically independent treatment zones in series. It shall be possible to keep the ESP in service. even when one zone becomes unavailable. The supporting structure shall be made of steel.

A corrosion and heat resisting steel grid shall be provided at the inlet to each precipitator to prevent large pieces of partly burned particles which may be present to the gas stream. from entering the collecting zone.

334

The spraying and collecting electrodes shall be designed for easy replacement. , Sectionalized collecting electrodes would be preferred.

Dust/ash loading shall be considered when designing raw gas dueling. To prevent the formation of condensed water and as protection against freezing. the ESP shall be equipped with an electrically operated heating system for the complete fly ash hoppers.

The insulator devices at the HV inlet passages shall be healed electrically and designed for easy replacement.

The gas-tight casings. access doors and peep holes in the casings of electrical and mechanical connections shall be designed to minimize air leakage into the ESP. Internal pockets or ledges where ash might accumulate shall be avoided wherever possible. The rapping gear for the collecting electrodes shall as far as possible be arranged inside the ESP. The intensity and frequency of the rapping shall be variable and the gear shall operate without undue noise.

Expansion joint shall be provided from steel with inside protection against erosion.

The Contractor shall take all necessary steps to ensure free ash flow out of the hoppers. A rapping mechanism which raps intermittently at the hopper shall be provided to avoid bridging of fly ash in the hopper.

The hopper shall be effectively dried out during commissioning and shall be insulated as specified to prevent condensation which impedes removal of the dust. The dust hoppers shall be provided with ash bridge -breaking devices of the approved type which shall be a permanent fixture arranged near the outlet from each hopper and operable from a platform underneath the hopper when the precipitator is in service.

The hoppers shall be furnished with double rotary locks for isolation.

Special attention shall be given to ensure uniform flue gas distribution across the precipitator.

The local control panel for the precipitator shall be provided and placed near the ESP and shall cont61in all equipment and instrumentation for both automatic and manual controls. There shall be remote indication for from this cubicle to the mimic diagram of the central control panel to indicate precipitator operation status (e.g. ON and OFF). All precipitator and rapping gear fault alarms for the ESP shall be brought up by a common signal at the control room to all alarm panels.

335

A safety interlock system shall be provided to prevent any access into the ESP unless the electrical equipment is isolated and earthed.

The electricity to each collecting zone shall be supplied from separate rectifiers with independent high voltage automatic controls arranged to ensure maximum efficiency of ESP. PCB filled transformers will not be permitted.

The dust level in the ESP hopper shall be monitored and an alarm given if the dust level becomes too high.

Access shall be provided to each insulator compartment, to each hopper and before and after each field.

All electrical heating of the precipitators shall be under thermostatic control on the 'local panels. The temperatures of the heated surfaces shall be monitored and in case of low temperature, provision shall be made for alarms which will be raised at the ESP control panels.

During commissioning the Contractor shall make measurements to determine the following:

• flue gas distribution across the inlet cross-section of ESP • inlet dust loading • dust size distribution before ESP • dust properties • dust size distribution alter ESP • dew point of the flue gas.

The results shall be submitted to the Client/Consultant.

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Section B4: Air and Flue Gas System

Technical Data by BIdder/Contractor Unit Data

Air flows

Forced draught fan m3/s

Primary air fan m3/s

Flue gas flows

Regenerative air preheater primary side:

wet/dry (m3 at 0 0C, 1013 mbar)

m3/s m3/s

Regenerative air preheater secondary side:

wet/dry (m3 at O�C, 1013 mbar)

m3/s m3/s

Flue gas recirculation fan:


m3/s m3/s

Stack inlet:


m3/s m3/s

Air pressure

FD fan outlet mbar

Secondary steam air heater outlet mbar

Primary air fan outlet mbar

Downstream of air preheater:

• Primary side

• Secondary side mbar

Upstream of air preheater:

• Primary side mbar

• Secondary side mbar

Before burners mbar

Flue gas pressure

Combustion chamber mbar

Before superheater mbar

Before economizer mbar

Before air preheater mbar

Before ESP mbar

B4/FD-1

337




At ID fan suction side mbar

At stack Inlet mbar

Flue gas recirculation fan Inlet mbar

Flue gas recirculation fan outlet mbar

Air temperatures

Ambient °C

Primary steam heated air heater outlet °C

Secondary steam heated air heater outlet °C

Regenerative air healer outlet:

• Primary part °C

• Secondary part °C

Pulverizer inlet °C

Forced draft fans

Manufacturer -

Number pcs


Capacity of each (m3 at 00C. 1013 mbar) at design Point m/s

Total pressure head at design point Type of air inlet control mbar

Type of bearing

Number of air inlets pcs

Fan efficiency at MCR % Power consumption at MCR

kW

FD fan motor:

•••• Manufacturer

•••• Power kW

•••• Related voltage kV

•••• Speed rpm

•••• Cooling water consumption

kg/s

B4/FD-2

338




Sealing and cooling air fans

Manufacturer -

Type -

Number -

Type of bearing -

Fan speed rpm

Inlet temperature 0C

Steam air preheaters

Manufacturer -

Number of steam air preheaters pcs

Heat exchange area m2

Steam mass flow rate kg/s

Steam pressure at inlet bar

Condensate temperature at outlet 0C

Combustion air mass flow rate Combustion kg/s

Combustion air temperature at inlet 0C

Combustion air temperature at outlet 0C

Pressure loss on the combustion air side bar

Tube material -

Forms of tubes (oval or round) -

Fin material -

Pitching of fins mm

Thickness of fins mm

Weight t

Regenerative air preheater (RAH)

Manufacturer -

Number pcs

Type -

Heat exchanged MW

Total heating exchange area m2

Hot end layer height m

Cold end layer height (ceramic/enamelled) m

Stator diameter resp. rotor diameter m B4/FD-3

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Hot end plate thickness mm

Cold end plate thickness mm

Material of the hot end plates -

Material of the cold end plates (ceramic/enamelled) -

Inlet flue gas flow rate with particlates kg/s

Outlet flue gas flow rate with particulates kg/s

Inlet combustion air flow rate kg/s

Outlet combustion air flow rate kg/s

Total weight incl. motor t

Inlet flue gas temperature oC

Outlet flue gas temperature oC

Inlet combustion air temperature “c

Outlet combustion air temperature “c

Minimum mean heating surface temperature at cold end layer outlet “c

Rotational speed mm-1

•••• Manufacturer -

•••• Type -

•••• Rating kW

•••• Rated voltage kW

•••• Speed min-1

Cleaning equipment for RAH

Manufacturer -

Number of sootbloers per RAH -

Type -

Duration of one sootblowing cycle min

Operating time of a sootblower per cycle min

Steam consumption per sootblower and cycle/AH kg

Steam consumption of all sootblowers and cycle/RAH kg

Number of sootblower cycles per day -

B4/FD-4

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RAH washing installation

Washing medium -

wash water flow kg/s

Duration of washing process h

Wash water pumps

Manufacturer -

Type pcs

Number kg/s

Flow rate

Induced draught fan (ID fan) pcs

Number of ID fans per boiler -

Manufacturer -

Type kg/s

Delivery capacity at design point mbar

Total pressure head at design point kg/m3

Density of flue gas (STP) %

Efficiency at MCR kW

Max. allowable flue gas temperature oC

Type of controller -

Gearbox manufacturer -

Type -

Range of control -

Weight per fan and motor t

Motor:

•••• Manufacturer -

•••• Type -

•••• Rating kW

•••• Rated voltage kV

•••• Speed min-1

Cooling water consumption kg/s

B4/FD-5

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Flue gas recirculation fan (if necessary)

Manufacturer -


Number of fans pcs

Capacity of each (m3 at O0 C. 1013 mbar) m3/s

Capacity of each m3/s

Static head mbar

Type of inlet control

Fan motor:

• Manufacturer

• Power kW

• Rated voltage kV

Speed rpm

Cooling water consumption kg/s

Electrostatic precipitator (ESP)

Manufacturer -

Number of ESP pcs

Number of treatment zones in series per ESP pcs

Specific absorption surface m2/m3/s

Collecting electrodes

Type -

Thickness mm

Material -

Number per treatment zone -

Total number per unit -

Effective height m

Projected area per zone m2

Total projected area per unit m2

Effective area per unit m2

Pitch mm

B4/FD-6

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Discharge electrodes

Type -

Thickness mm

Material -

Number per treatment zone -

Total number per unit -

Effective length between

• plates mm

• pitch mm

Minimum flash over distance between electrodes mm

Number of HT sets per zone -

Number of HT sets per unit -

Type of rectifier -

Type of rapping gear

Collecting electrodes -

Discharge electrodes -

Frequency or rapping -

Steel casings

Thickness mm

Casing design temperatures °C

Casing design static gas pressure mbar

Type of insulation / Thickness of insulation mm

Method of insulation attachment -

Type of external finish -

Hoppers

Number of dust hoppers per precipitator -

Capacity of each dust hopper t

Tolal capacity of dust hoppers t

Dust density on which above is based kg/m3

Thickness of hopper plates mm

B4/FD-7

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BPDB, Barapukuria Power Plant Bidder/Contractor Section B4: Air and Flue Gas System


Type of heating of hopper (total hopper) -

Type of rapping gear -

Type of rapping -

ESP outlet dust burden at STP (dry) adjusted to 5% CO2 g/m3

CO2 content %

Gas temperature °C

Gas volume at inlet conditions

• dry m3/s

• wet m3/s

Carbon content of dust %

Density of dust g/m3

Anticipated dust burden at (STP, dry)

• furnace outlet g/m3

• ESP inlet g/m3

• ESP outlet (at 5% 02) mg/m3

Collection efficiency of ESP P/o

Gas velocity in treatment zone mls

Treatment time s

Draught loss mbar

Temperature drop in ESP °C

Rated capacity of each HT set kW

Ash discharge capacity In �case of silo loading t/h

B4/FD-8

344

Ash Handling System

345

B5. Ash Handling System

5.1 General


5.2.1 Bottom as removal system

5.2.2 Fly ash removal system

5.2.3 Ash slurry system


5.3.1 General features

5.3.2 Bottom ash removal system

5.3.2.1 Crusher

5.3.2.2 Bottom ash bunker

5.3.2.3 Ash hoppers. gates and dust isolating valves

5.3.2.4 Belt conveyors for ash handling


5.3.3.1 Jet conveyors

5.3.3.2 Intermediate fly ash bunker (if necessary)

5.3.3.3 Pressure vessel ash conveyors

5.3.3.4 Air slides

5.3.3.5 Rotary seal and traversing chutes

5.3.3.6 Heating system

5.3.3.7 Flat isolating valves

5.3.3.8 Exhaust air filters. exhaust fans. air supply system

5.3.3.9 Fly ash silo

5.3.3.10 Compressed air system

5.3.3.11 Slurry pumps. waste water pumps

5.3.4 Pyrite removal (pulverizer rejects)

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B5 Ash Handling System 5.1 General

The design and supply of the ash handling system shall include all ash handling equipment necessary to remove the ash from following sources:

• furnace (bottom ash) • pulverizer rejects • economizer • regenerative air preheater (AH) • ESP

Basically the ash handling system is subdivided into a pneumatic and hydraulic conveying system.

The ash from the furnace pulverizers and economizer shall be integrated into the bottom ash removal system.

The ash from AH shall be conveyed to a ash mixing vessel/ash conveyor pump slurry pump). By this ash slurry pump the ash shall be pumped via pipe lines to the ash settling pond.

The ash from the ESP and economizer shall be transported by a pneumatic conveying system.

This specification covers the systems required for extraction transportation within the boundary or the power station storage and for lading of the bottom ash and fly ash together with the relevant ancillaries corresponding to the design date of this section (data sheets B5/FB).


This section sets out the scope of the installations covered by this specification as well as requested supplies and services but without excluding other necessary components and services not mentioned.



• 1(one) drag link scraper ash/slag extractor complete with driving unit for variable speed air tight casing tensioning device for drag link all electric drives base frames. steel structure, etc designed for operation with process water

• ash/slag chute for feeding the scraper conveyor • complete process water cooling system • connecting pipes separating valves. controls to the process water circulating

system • complete ash, slag crusher including gear, motor coupling base plates and

anchoring holts

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• complete ash conveying system starting from ash/slag crusher outlet up to the bottom ash silo inlet including belt conveyor tripping conveyor (or shuttles) driving units complete with gear and motors

• protection devices corner tower und transfer stations (if necessary), supporting structure together with galleries stairs, gangways, cladding of steel structure. structural members Il)r fixing lining appliances for dismantling of various com-ponents

• bottom ash silo including lining, steel support structure, shut-off gate, loosening and discharge equipment, hopper, all mechanical, electrical and control equipment associated with the silo

• protection facilities to protect equipment against the adverse effect of process water

• drag link conveyor below the bottom ash silo • truck unloading facilities • hydraulic ash discharge including mixing vessel.



• ash hoppers under the second flue gas path (if any) regenerative air preheater and ESP including one manually operated shut-off valve and one automatic opening gate for each hopper

• complete electrical trace heating system to all hopper, ash chutes, rotary locks, cellular wheel sluices

• jet conveyors for each extraction hopper together with compressed air cock and fans for jet conveyors (one 100% standby) including base frames electric motors. Sound attenuation facilities (silencers. sound insulation)

• all interconnecting pipe work and valves for jet conveyor air • all connecting pipes from the jet conveyor up to the intermediate fly ash

bunker • Intermediate fly ash bunker, together with cyclone separator for waste air

purification; electrically or pneumatically actuated gates to be installed under the bunker and electric heating facilities for heating of the bunker hoppers

• ash pressure vessel conveyors (one in standby) consisting of pressures vessels ash inlet valve air intake valve control and vent valves drainage valves pressure nozzles and all sensors actuators and instruments for functional group control

• rotary air compressors inclusive bed plates anchoring bolts coupling electric motors, silencer, air suction, filters non return valves, safety valves, air coolers air storage tanks. all necessary instruments and sound attenuating insulation (if required)

• fly ash silo waste air filters of the bag filter type, including filler with bunker mounting collar, rappers with actuators, suction and scavenging air fans, inclusive coupling and motors

• all necessary interconnecting pipe lines and valves between ash pressure vessel conveyor, intermediate bunker, fly ash silo rotary air compressors blow-off silencers .

• fly ash silos including lining, steel support structure, with bottom fluidizing equipment (fans, gates, pipes, hopper, all mechanical electrical and control

348

equipment associated with the silo).

5.2 Ash slurry system


• Ash/water mixing vessel with all associated equipment • pump service vessel • ash slurry pumps with electric drive. flexible coupling • piping for mixing water • ash slurry transport system with all necessary pipeline work valves etc. • water recirculation system from ash pond to ash/water mixing vessel including

recirculation water pumps • facilities for drainage and cleaning of the slurry pipelines • pipeline scraper.


5.3.1 General features

The design of the fly ash and bottom ash (slag) handling system shall be based on the following considerations:

The ash and slag disposal are (ash settling pond) will be located inside the bound-ary of the Power Station. There for transportation or ash and slag shall be made by suitable conveyor systems. Silo discharge facilities for bagging (50 kg bag) and truck Ioading has also to be provided.

The location of storage and loading facilities (silos, bunkers. etc.) shall allow a centralized handling or fly and bottom ash irrespective or the design/system variant chosen. The arrangement of these facilities shall not interfere with the operation area of the boiler.

All possible measures shall he taken to protect components which are coming into direct contact with process water against its adverse effects (use of material, etc).

The ash handling system shall be designed and constructed in view of a "dust free" operation.

The ash handling system shaII be operated fully automated.

Fly ash shall be collected from the flue gas pathes of the steam generator (if applicable), the air hoppers and from the hoppers of ESP. It shall be envisaged to conveyed as much as possible fly ash with pneumatic conveyors. A dense lean phase dry pneumatic system (e.g. air slide) under each fly ash hopper to convey the fly ash to the fly ash silo shall be installed.

The discharge of the ash resulting from some of the above points into the bottom ash removal system will also be accepted, provided the ash temperatures necessitate it for safety requirements.

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In order to prevent clogging of ash in bunkers, silos and lines appropriate measures such as provision of ash fluidizing air, lining (or manufacturing from special material) of the bunker bottoms, etc shall be taken.

When selecting the individual equipment special attention shall be paid to resistance against erosion. Suitable erosion resistant linings (e.g. for bottom ash hoppers, slurry pipes, etc.) shall be provided.

The air slide fluidization and conveyor air are each generated in two ventilators respectively compressors whereby one is “on standby", the air shall be dried and, if necessary, heated. The fly ash silo shall be isolated and heated.

The 4 (four) ventilators (compressors) for the two pneumatic conveying systems are parallel connected to a pipeline, so the four ventilators /compressors can be spare for each other.

In order to limit the wear-and-tear in the conveyor piping, the following precautionary measures are taken:

•low conveyor speed/velocity •large wall/thickness •lining of the pipe elbows which are easily replaceable.

Insofar as the conveyor piping is place over long distances in the open atmosphere. These parts are to be isolated.

All the pneumatically charged intermediate and collecting silos and loading silos are each equipped with two exhaust air Filters - designed as bag filters and two exhaust air ventilators, of which one or each is "on standby". Exhaust air installations in the open air shall be enclosed.


The relevant equipment shall perform the following tasks:

•extraction or the bottom slag/ash from the furnace •preparation of the bottom ash for transport •transport and settling of slag/ash •bagging and loading into trucks

The bottom ash from the furnace drops into a drag link scraper extractor. Ash extraction from the furnace shall be accomplished in continuous operation. The drag link scraper extractor conveys the bottom ash from the process water filed slag extractor box to a slag/ash crusher. A suitable conveyor system transports the slag to the bottom ash silo. Construction (e.g. number of components, elevation, etc.) and accessories shall ensure the decantation of water and the loading into trucks.

The bottom ash slag removal system has to be designed for worst coal operation. The submerged scraper conveyor is to be constructed in such a

350

way that the wet slag can be cooled in the water basin and extracted by conveyor equipment without a problem at all boiler loads and the total coal range.

Floating ash/sing is to be prevented by means of a corresponding arrangement of water spray.

One submerged scraper conveyor is to be arranged under each ash/sing chute of' the boiler furnace. The submerged frame in the water basin must guarantee an absolutely tight seal against air ingress into furnace.

The drag link scraper ash/slag extractor shall be of the semi-wet type. The lowest part of the conveyor shall be located under the furnace hopper. Consideration shall be made with regard to the relative expansion of the furnace and the drag link scraper and to exclude the intrusion of false air via the extractor into the boiler.

Bottom and side walls of the extractor shall be lined to avoid excessive erosion.

The quenching water shall be injected into the conveyor in the part were the slag is falling into the water bath in order to smash the big pieces of slag.

The removable submerged scraper conveyor is to be manufactured in welded plate construction with profile stiffening brick lining cooling water overflow basin including water discharge pipe (including draining equipment).

The drive motor of the conveyor chain is to be connected to a hydraulic item and via elastic coupling to a step-down transmission. By means of a continuously variable adjustable gear the conveyor speed shall be adjustable to the respective quantities of ash/slag as to minimize wear.

The capacity of auxiliaries shall be selected under the consideration that for load changes the ash flow may reach three times the ash now at normal continuous operation. Due to the above the conveyer shall be equipped with drive with variable speed and with safety clutch.

The slag extractor shall be equipped with a device enabling to change over from dumping on the conveyor belt to dumping into a small hopper from which the bottom ash can he taken over by a trolley.

Suitable openings for inspections shall be provided.

5.3.2.1 Crusher

The crusher shall he provided with dust proof shaft passages. Casing doors shall with quick look for checking and exchanging wear pans.

The shaft shall be supported from both sides in amply sized and dust proof self aligning roller bearings.

For conveyors or short length, fixed installed tension devices may he used while for conveyors of longer length tension carriages or equivalent self-regulating

351

tension devices to be used.

Corner towers if necessary) shall consist of steel frame work and outside cladding. Intermediate stairs and steps shall be provided with grid floorings.

Above the conveyor heads or take-up stations respectively trolley beams for a payload of 3 tons shall be provided. The bottom ash supply into bottom ash bunker shall be done by means of a horizontal tripper conveyor. For drives, brakes, etc. the general provisions stated in other specifications for cranes and hoists will apply.

5.3.2.2 Bottom ash bunker

The bottom ash bunker associated to the mechanical ash handling system shall fulfill the following requirements:

Inclination of bottom, lining of bottom and loosening and discharge facilities shall be selected in order to exclude clogging of the bunker to the maximum possible extent. The bottom ash bunker shall be of welded construction from steel plates.

Provisions shall be made for draining the rest water of the bottom ash. Bunker shall be designed to be suited for loading into trucks. Truck loading may be performed. Feeders for truck loading shall be provided with electrically or pneumatically actuated shut-off devices and rubber chutes.

For decantation of water and for storage and/or loading also separate bunkers or separate compartments of one bunker may he used.

Because the system operates with process water, bunker shells shall be of suitable material.

5.3.2.3 Ash hoppers, gates and dust isolating valves

Each fly ash hopper shall be fitted with two valves: one gate shut-off valve hand wheel operated and one automatic opening gate (with pneumatic or electric actuator).

The transfer chute with built-in grate (e.g. light mesh size of about 100 x 100 mm) and a flap to a belt conveyor connected down stream is to be installed behind the scraper conveyor. In case ash/slag parts do not fall through the above grate, they are to be directed from the grate to a crusher, to be crushed and then also transferred on to the belt conveyor.

The crushing tools shall he manufactured from highly wear resistant special material. The bearings shall he manufactured so as to prevent the ingress or dirt and ash/slag granules.

Between electric motor and gear a flexible coupling shall be provided, while be-tween gear and crusher slipping clutches are required.

352

5.3.2.4 Belt conveyors for ash handling

Wherever applicable, the belt conveyors must be lodged in closed conveyor bridges.

A unilateral walkway with open grid flooring shall be provided parallel to all conveyors. Idler sets shall be provided with labyrinth seals and shall run true. Bearings shall be of the maintenance free type, i.e. lubrication shall be required not more frequent than once per year.

Drive pulleys tail and take-up pulleys shall be of closed design.

Pedestal bearing shall be provided with labyrinth seals.

Belt scrapers shall be arranged at the discharge pulley and, if necessary, for tail pulleys.

Material and construction of covering plates between upper and lower discharge hoods and product guides shall be chosen in view of optimum sliding behaviour of the product, avoidance of clogging and limitation of noise. Material shall be stainless steel, reinforced fibre glass or equivalent. Rubber aprons for guidance shall be provided.

Gears shall be of the lip on type. Flexible or hydraulic start-up couplings (depending on requirements) shall be used.

Retention assemblies such as limit switches, true run switches, belt monitors, lanyard switches shalI form part of the mechanical equipment of the conveyor plant


The fly ash handling system shall be of the pneumatic type.

The ash accumulated under the boiler second path (if applicable), at the air pre heater and under the ESP shall be discharged pneumatically in continuous operation by means of jet conveyors. If necessary, the jet conveyors shall deliver the ash into an intermediate bunker. The intermediate bunker shall be arranged near to the steam generator. Compressed air for the air jet conveyors shall be supplied by two rotary fans (one of which will serve as standby). For heating up of the conveying air a steam coil air heater (or an electric heater) shall he provided.

The transport of the ash from the intermediate bunker and fly ash silos shall be made by conveying systems suitable for transport of fly ash over longer distances (so called “air pressure vessel conveyors”). The fly ash shall be conveyed to a joint fly ash silo and loading plant which serves both units.

Exhaust air from intermediate bunker and fly ash silo shall be removed via adequate filters. At the fly ash silos exit, the ash shall be wetted by a humidifying

353

worm conveying system using process water. For fly ash silo fly ash fluidization shall he provided.

The following requirements have to be considered by the Contractor:

• all the pressure vessel conveyors, conveyor lines and switch points are to be provided for 100% quantity at five conveyor cycles per hour

• the exhaust air filter unit-located on the intermediate bunker (if necessary) is to be supplied redundantly

• all the bends and loops in the conveyor lines to the fly ash silo are to be provided with wear protection lining (fusion-cast basalt) .

• all the service and instrumentation air stations are to be designed redundantly in total

• the service air for low pressures up to 1.5 bar is to be generated by rotary piston blowers; the service air for higher pressures and the instrument air are to be generated by screw type compressors. All the compressors must be completely designed as dry running compressors '

• air receivers and adsorption dryers are to be connected down stream of the screw type compressors; air heating is 10 be provided for the rotary piston blowers (if necessary)

• all the units are to be provided with a sufficient number of inspection, poker holes and drain holes

• all fly ash pipes have to be equipped with tube connections (studs) and valves for blowing fee the pipes in case of blockages

• all hopper gates, ash chutes, rotary locks, air conveying chutes, etc. are to be equipped with electrical heating systems (if necessary)

• all ash silos have to be equipped with anti-bridging devices • all fly ash conveying equipment, the complete exhaust air filter unit as well as

the piping with heated air are to be provided with insulation as well as insulation cover plates

• exhaust fans connected down stream of the exhaust air fillers are to be equipped with vane controllers to keep the vacuum in the ash silo constant

• a sufficient number of duct isolating valves are to be installed in the air slide system so that certain chute sections can be closed for repairs during operation

• fine meshed grates above the duct cloths installed in the air slide are to be provided.

• fans and blowers must be designed with two bearings • shafts of dust conveying units must in addition to the usual seals, also be

provided with grease seals to avoid dust exit (with arrangement of bearing and seal in and housing).

5.3.3.1 Jet conveyors

Jet conveyors shall be designed for the maximum flue gas temperature prevailing at their branch point. One separate jet conveyors shall be attributed to each ash extraction point. Above the jet conveyors electrically (or pneumatically) operated shutoff gates and pipe switch points for optionally discharging the wash water or ash shall be arranged.

354

5.3.3.2 Intermediate fly ash bunker (if necessary)

Intermediate fly ash bunker shall be of welded construction from steel plates. The intermediate bunker shall be equipped with a cyclone separator from where the waste air shall be laid to the gas duct before the ESP.

5.3.3.3 Pressure vessel ash conveyors

Pressure vessel ash conveyors shall be used for conveying heads which cannot be mastered by jet conveyors.

Ash pressure vessel conveyors shall be suited for dry (purely) pneumatic transport of fly ash.

Pressure vessel with all piping connections electrically controlled loading and unloading fittings inspection doors electrical level measurements including auto-matic control system shall be provided.

5.3.3.4 Air slides

Air slides are to be provided with inspection glass and hand hole covers at intervals of at least 3 m.

The insulation must be split designed and be provided with quick action service locks.

5.3.3.5 Rotary seal and traversing chutes

The rotary seal and traversing chutes are to be equipped with hand hole covers so that impurities can be removed. The rotary seal sluices arc to be provided with protruding stub shafts and square shafts so that they can be turned back by hand for the purpose of removing impurities.

5.3.3.6 Heating system

All the hopper gates in the ESP, collecting bunker coal chutes rotary locks cellular wheel sluices and air conveyor chutes are to be equipped with steam trace heating including the necessary isolating valves and condensate separators. If steam is not available they arc to he equipped as electrical trace heating (at least 400 Watt/m2).

A list showing which plant parts are to be provided with heaters must accompany the offer.

5.3.3.7 Flat isolating valves

Flat isolating valves - electrically or pneumatically operated - may not be employed as operational valves in dust conveying plant parts (permitted only as emergency isolating valves).

355

5.3.3.8 Exhaust air filters, exhaust fans, air supply system

The exhaust air filters are to be designed as bag filters with compressed air pulse dedusting, differential pressure monitoring including remote display access doors exhaust air filter bunkers including electrical trace heaters (400 Wattlm2) and exhaust fans including vane controller system,

The two fly ash silos and two storage bunkers are to be equipped with one exhaust fan and one exhaust air filter each.

Every exhaust air filter shall be designed for the dedusting of the conveyor air from the pressure vessel conveyor unit of ESPs of both storage bunkers as well as the exhaust air from loading equipment.

5.3.3.9 Fly ash silo

The fly ash silo shall be of welded construction from steel plates.

Inclination of bottom, lining of bottom and discharge and/or ash extraction devices shall he selected to exclude clogging to the maximum possible extent.

For loosening of ash each silo shall be provided with a bottom fluidizing system operating with air.

The fly ash silos shall be air tight and shall be protected with bunker over pressure/under pressure flaps.

Arrangement of silos shall permit direct loading of ash into trucks or rail wagons. The silos shall be equipped at the outlet with a gate and humidifying system (worm or equivalent).

Optionally the fly ash shall be carried from the ash silo to the drag link conveyor below the bottom ash silo. By this conveyor, the fly ash is fed into the mixing vessel at the hydraulic ash system.

5.3.3.10 Compressed air system Compressed air supply systems or slides intermediate pressure vessel conveyor and fly ash collecting hunker pressure vessel has to he supplied. Three complete rotary piston blower stations (one of which is to be a 100% standby) with electrical air preheating, the necessary piping and all fittings as well as suction and discharge silencers and filters. The air should be generated oil free. Air supply of boiler and ESP hopper is to be equipped by three complete screw-type compressor stations (one of which is to be a 100% standby including piping all fittings as well as suction and discharge silencers and filters. Cooling shall be made by dosed auxiliary cooling water. Material of cooler shall be selected accordingly.

356

This also includes all the piping to the jet conveyors as well as their continuation to the fly ash silo, respectively intermediate bunkers including all fittings and the jet conveyors.

The compressed air stations are to be designed in accordance with state-of-the-art technology, including for example standby quick throw-over switches, dryers, storage basins and condensate discharge lines as well as electrical binary and analog measurement equipment. ..

5.3.3.11 Slurry pumps, waste water pumps

The pumps mentioned above shall be able to handle ash slurry and dirty water. Therefore pumps with low speed (low circumferential velocities) shall be selected. Number of pumps shall be selected according to the function of the specific physical arrangement. All pumps shall be provided with double capacities.

5.3.4 Pyrite removal (pulverizer rejects)

The pyrites collected ill the pyrite container of each mill shall be conveyed to the bottom ash handling system by belt conveyors and/or hydraulic conveyors. Parts having a particle size larger than 40 mm shall be removed manually using a trolley.

357

BPDB, Barapukuria Power Plant Minimum Requirements

Section B5: Ash Handling System


Data for equipment capacity selection

Coal - as per Annex

Boiler rating for capacity determination of ash handling plant - MCR of boiler

Safety factor for design of conveying elements and equipment - 1.1

Safety factor for capacity selection of storage equipment - 1.0

Design ash quantities (minimum) for removing elements

• combustion chamber % 25

• second pass/air pre heater % 15

• ESP % 90

Net storage capacity of bottom ash bunker corresponding to the ash production at MCR

days 2

Net storage capacity of fly ash bunker corresponding to the ash production at MCR

days 2

Net storage capacity of the intermediate fly ash bunker corresponding to the ash production at MCR

hours 8

Net retaining capacity of the hoppers of the ESP corresponding to the ash production at MCR

hours 4

Capacity of bagging system and truck loading devices shall permit the emptying of the bunker content within

hours 4

Max. velocity of belt conveyors m/s 2.0

Minimum number x capacity for unit related equipment

Drag link scrapper extractor (bottom ash) 1 x 100%

Ash/slag crusher 1 x 100%

Ash bell conveyor up to bottom ash silo 1 x 100%

Bottom ash silo 1 x 100%

Fly ash silo 1 x 100%

Jet conveyor air fans (if any) 2 x 100%

Jet conveyor air preheater (if any) 1 x 100%

Fly ash pressure vessel conveyors 2 x 100%

Rotary air compressor 2 x 100%

Ash slurry pumps 2 x 100%

Water recirculation pumps 2 x 100%

B5/FB-1

358




Operating data

Data shall be filled in for guarantee coal at MCR

Ash resulting from:

• furnace kg/h

• 2nd pass (if any) kg/h

• air pre heater kg/h

• ESP kg/h

• rejects of coal mills kg/h

Total amount of ash kg/h

Bulk densities considered for calculation:

• dry combustion chamber ash (bottom ash) kg/m3

• dry fly ash kg/m3

• rejects of coal mills kg/m3

• humidified fly ash kg/m3

• moist ash from combustion chamber kg/m3

• specific gravity of bottom ash kg/m3

Bottom ash handling system

Electric power demand kW

Instrument air demand m3/h

Process water demand kg/h

Drain flow to sewage kg/h

Fly ash handling system


Instrument air demand m3/h

Process water demand kg/h

Ash slurry system


Process water demand (hydraulic transportation) kg/h

B5/FD-1

359

BPDB. Barapukuria Power Plant Bidder/Contractor



Design Data

Bottom ash handling system

Submerged link scraper slag extractor

Number pcs

Type -

Conveying capacity kg/s

Turndown range -

Gradient of the inclined section 0

Type of chain -

Chain speed at MCR m/s

Clearance width of trough m

Trough volume referred to max. water lever m3

Motors:

• manufacturer -

• type -

• rating / rated voltage kW/ kV

• speed rpm

Required water quality -

Water mass flow rate kg/s

Chemical additives (if any) • type -

• quantity kg/h

Weight of conveyor t

Content of sediment in the water mg/l

Water content in ash/slag at extractor outlet %

Crusher for ash/slag Manufacturer -

Type -

Number pcs

Capacity t/h Power demand kW Bulk density kg/m3 Screen dimension mm Final grain size mm

B5/FD-2

360




Motors

• manufacturer -

• type -

• rating kW

• rated voltage kV

• Speed Min-1

Belt conveyors

The Bidder/Contractor shall fill in the following data for each belt conveyor.

Type -

Manufacturer -

Belt width mm

Height of borders mm

Shaft centres m

Handling capacity kg/s

Belt velocity m/s

Idler spacing in the upper stand m

Idler spacing in the lower stand m

Drive power kW

Bottom ash silo

Number of silo -

Type -

Net volume m3

Overall dimensions (length/width/height) m/m/m

Inclination of bottom 0

Number of bagging and truck loading connections -

Material

• shell --

• bottom lining -

Type of bottom ash silo extractor shell ---

Capacity of bottom ash silo extractor kg/h

B5/FD-3

361




Fly ash handling system

2nd flue gas pass ash removal

Number of tapping points pcs

Type of gates �

Size of gates �

Number of jet conveyors pcs

Conveying capacity kg/h

Conveying distance m

Air preheater hopper ash removal

Number of tapping points pcs

Type of gates '"

Size of gates -



Conveying distance m ESP hopper ash removal

Number of hoppers pcs

Type of gates -

Size of gates -




Jet conveyor air fans (if any) Number of fans pcs

Type of fans �

Manufacturer -

Air flow rate m3/s

Discharge pressure mbar

Motor speed rpm

Rating kW

Air inlet temperature at MCR 0C

B5/FD-4

362




Jet conveyor air heater (if any)

Type -

Number -

Heat rate MW

Heating surface m2

Air inlet temperature 0 C

Air outlet temperature 0 C

Intermediate fly ash bunker (if any)

Number of bunkers -

Type -

Net volume m3

Overall dimensions (length/ width/ height) m/m/m

Number of compartments -

Number of tapping points from bottom -

Inclination of bottom 0 Type of outlet gates -

Material

• Shell -

• bottom (lining) -

Air pressure vessel conveyors

Type -

Manufacturer -

Number -

Handling capacity of each kg/h


Air demand (m3 measured in 00 C, 1013 mbar) m3/s

Air pressure bar

Rating kW

Speed rpm

B5/FD-5

363

BPDB, Barapukurla Power Plant Bidder/Contractor



Air compressors for pressure vessel conveyors

Number pcs Type - Air now rate for each m3/h

Delivery pressure bar

Rating kW

Fly ash silos

Number of silos -

Type -

Net volume m3

Overall dimensions (length/width/height) m/m/m

Inclination of bottom 0

Number of bagging system and truck loading connections

-

Material :

• shell -

• bottom (lining) -

Fly ash silo exhaust air filter

Type - Manufacturer - Number per Silo Exhaust air handling rate m3/h

Max. temperature °c .

Rapper power demand kW

Motor rating kW

Motor rating for suction and scavenging air ran kW

Collecting efficiency of precipitator % Silo bottom fluidizing air fans Number of fans pcs Type of fans - Manufacturer - Air now rate m3/s

Discharge pressure mbar B5/FD-6

364




Motor speed rpm

Motor rating kW

Mixing worm conveyors

Number pcs

Worm length - Product to be handled -


Number of inlets pcs

Rating kW

Motor speed rpm

Material:

• casing - • worm -

Process water demand kg/s

Ash slurry system

Slurry pumps

Number pcs

Manufacturer -

Type/arrangement - Flow rate per pump kg/h

Speed min-1

Rating kW

Material:

• impeller - • casing -

Slurry water recirculation pumps (if applicable)

Number pcs

Manufacturer -

Type/arrangement - Flow rate per pump kg/h

B5/FD-7

365




Speed min-1

Rating kW

Medium handled � Material:

• impeller �

• casing �

B5/FD-8

366

Water Storage and Treatment

Systems

367

B6. Water Storage and Treatment Systems

6.1 General

6.2 Scope of Supply and Services 6.2.1 Deep tube wells and pump houses 6.2.2 Raw water storage and supply 6.2.3 Demineralised water treatment plant 6.2.4 Demineralised water storage tank and pumping station 6.2.5 Chemical handling and storage facilities 6.2.6 Dosing system for condensate, boiler feed water and

cooling water conditioning

6.2.7 Condensate treatment system 6.2.8 Potable and service water system 6.2.9 Waste water treatment 6.2.10 Chlorination system 6.2.11 Laboratory

6.3 Special Technical Requirements 6.3.1 Demineralised water treatment plant 6.3.2 Conditioning plants 6.3.3 Condensate treatment plant


368

B6. Water Storage and Treatment Systems

6.1 General

This specification covers the design manufacturing and supply of the complete water storage and treatment system for the entire specified power plant.

Discharge water from coal mine after required treatment will be used as cooling water and the existing deep tube well water will be used for potable water & demi water production of the proposed 250 MW. At present approx. 1200 MT/ hr is discharged from the Coal mine. Coal mine discharge water quality is mentioned below:

Sl no. Test Item Unit

1. PH 8.35 2. Conductivity 360 µs/cm 3. Iron (Fe) 0.95 mg/l 4. Silica (sio2) 37.5 mg/l 5. Suspended Solid 187 mg/l 6. Turbidity 3.2 NTU 7. Total dissolved solid 157 mg/l 8. Chloride (Cl) 9.6 mg/l 9. Hardness 2.66 mmol/l

The water storage and treatment system of this section includes the following parts

• Cooling water

Coal mine discharge water receiving system from coal mine discharge water tank, Clarifiers (2 x 1200MT/ hr), Settling water tank (capacity 5000 m3), Pumps, Coal slurry tank, filters, chemical dozing system, Clear water tank(capacity 2000 m3), Cooling water supply system, Interconnection with the existing cooling water system.

Drainage system must be incorporated with all tanks/ reservoirs and clarifiers.

• Demineralised water

Raw water receiving arrangement from existing deep tube well system, Raw water tank (1000 m3), Filters (Fe-Mn filters, Multimedia filters, Cartridge filters), Clear water tank, RO plant ( 2 x 60 m3/ hr), Decarbonator (tank capacity 2 x 200 m3), Mixed bed ion exchanger, pumps, Demi water tank (2 x 1000 m3), Demi water supply system, Interconnection with the existing demi water system.

369

Drainage system must be incorporated with all tanks/ reservoirs.

• chemical handling and storage facilities

• dosing system for condensate and boiler feed water conditioning

• condensate treatment system

• potable and service water system

• waste water treatment system

• chlorination system

• laboratory for waste water and coal analysis

The demineralisation water plant shall be sized to serve all demineralised water consumers of the power generator units and common facilities. The quality of the treated raw water and condensate shall correspond with the requirements of the boiler feed water for the heat recovery system and operation of the associated steam turbine.

The waste water system or this sub-section shall be designed to cope with the waste water emission regulations.

The design of the water storage and supply systems shall consider necessary measurements for start-up and commissioning of the power plant. The requirements specified in BO.3.6 under Section 'Supply and Services' are to apply.


This section sets out the scope of the installations covered by this specification as well as requested supplies and services, but without excluding other necessary components and services not mentioned.

6.2.1 Deep tube wells and pump houses

Deleted

6.2.2 Raw water storage and supply

The scope of this equipment includes the complete raw water supply for demineralised water , service water, and potable water system. Raw water storage shall be done by one raw water storage tank.

Raw water tank shall be equipped with 2 x 100% raw water pumps as supply pumps. The raw water supply to potable water system demineralised water system and service water within the power plant shall include a filtration system and the complete piping system to the consumers valves, fittings and an adequate numbers of taps at the service water system. Raw water for demineralisation plant, service water and potable water system shall be existing deep tube well water.

370

6.2.3 Demineralised water treatment plant

The demineralised water treatment plant is to supply make-up water in sufficient quantity for boiler feed-water and for the auxiliary cooling water systems as well as for other consumers, which require high-purity water by demineralisation of raw water.

Demineralising process shall include Fe Mn filters, Activated carbon filters, Multi media filters, cartridge filters Reverse osmosis, Decarbonator, Mixed bed ion exchanging. Capacity of the RO plant shall be at least 2 x 60 m3/ hr (02 nos., each capacity 2 x 60 m3/ hr) on the basis of output (demineralised water production). Demi water production capacity of mixed bed shall be at least 2 x 120 m3/hr (02 nos., each capacity 2 x 120 m3/ hr). Membrane of RO plant and resin of mixed bed must be USA/ Europe origin. Colour of anion and cation resin will be different.

Included are chemical storage and dosing tanks, pumps, all necessary accessories and the complete electrical and instrumentation installation including one (1) local control panel at the water treatment building with monitor or mimic diagram indicators alarm systems terminal strips for transfer signals and all other electrical equipment for closed or open loop control function.

The instrumentation shall comprise necessary equipment for monitoring and automatic operation of the plant complete with remote control devices, push buttons selector switches signal lamps, alarm indication and electrical wiring.

6.2.4 Demineralised water storage tank and pumping station

The scope of this system includes all work required to install the demineralised water system including the demineralised water storage tanks (2 x 1000M3) and pumping station. It includes demineralised water supply pumps (2 x 100%) instrumentation, valves, piping, fittings, air-resp. CO2-sealing device for storage tank, welding, hangers and supports.

All piping of unconditioned demineralised water shall be 304L stainless steel.

6.2.5 Chemical handling and storage facilities

The scope of this equipment includes the chemical handling and storage facilities including at least one HCI-storage tank. one caustic soda storage tank complete with inlet. outlet level indicator drainage manhole vent with acid vapour absorption transfer pumps complete with connecting pipework. truck unloading station with unloading manifold hose connections. all necessary equipment and installation for safe operation of the station and a drum store for dosing chemicals.

6.2.6 Dosing system for condensate. boiler feed water and cooling water conditioning

371

Chemical feed - condensate

The scope of this equipment includes the condensate-chemical feed system which will consist of a skid-mounted stainless steel hydrazine and ammonia feed tanks and dosing pumps (2 x 100%) piping valves fitting welding. instrumentation and controls, hangers and supports, two barrel pumps with appropriate piping for emptying drums. Both hydrazine and ammonia will be fed downstream off the polisher vessels to scavenge oxygen and control pH.

Adequate space and means for maintaining the equipment shall be provided as well as for controlling containing and treating of spills.

The condensate chemical feed equipment shall be arranged to provide ammonia and hydrazine feed to the auxiliary boiler.

Chemical feed - Boiler

The scope of this equipment includes the boiler-chemical feed system which will consist of a phosphate feed lank with mixer and dosing pumps (2 x 100%) all mounted on a skid. along with piping valves fillings, welding instrumentation and controls, hangers and supports.

Adequate space and means for maintaining the equipment shall he provided. ns well as for controlling containing and treating of spills.

The boiler chemical feed equipment shall be arranged to provide phosphate feed to the auxiliary boiler.

Water sampling system

Analysis and recording for chemical control of the condensate feedwater boiler water and steam systems shall be provided by a sampling station in the boiler room. Boiler sampling station room must be ash free (air tight) and air cooled by air cooler.

The system will provide temperature, pressure and now control for continuous automatic analysis and recording. The equipment will consist of freestanding sampling panels, sink, conductivity cells, pH cells, oxygen analyzers, silica analyzers, sodium analyzers, hydrazine analyzer, recorders, components for either returning samples to the condensate system or dumping them to waste tubing piping valves instrumentation and controls.

Grab samples will be carried back to the central sampling laboratory located in the service building.

Samples to be piped to the panel shall include:

1. Condensate pump discharge 2. Condensate at deaerator inlet

372

3. Condensate deaerator outlet 4. Boiler feed pump discharge 5. Economizer inlet 6. Main Steam 7. Boiler blowdown 8. Condenser hotwell 9. Polisher outlet(after chemical feed) 10. Auxiliary boiler feed pump discharge 11. Auxiliary boiler blowdown

Conductivity measurement and recording shall provided for:

1. Condensate pump discharge 2. Condensate at deaerator inlel 3. Condensate at deaerator outlet 4. Boiler feed pump discharge 5. Economizer inlet 6. Main steam 7. Boiler blowdown 8. Condenser hotwell 9. Condensate polisher outlet(after chemical feed) 10. Auxiliary-boiler feedwater 11. Auxiliary boiler blowdown

pH measurement and recording shall be provided for:

1. Condensate pump discharge 2. Condenser hotwell 3. Economizer inlet 4. Boiler blowdown 5. Condensate polisher outlet (after chemical reed) 6. Auxiliary boiler feedwater 7. Main steam

Oxygen analysis and recording shall be provided for:

1. Condensate pump discharge 2. Deaerator inlet or outlet 3. Boiler reed pump discharge 4. Auxiliary boiler feedwater

Silica analysis and recording shall be provided for:

1. Boiler blowdown 2. Condensate polisher outlet 3. Economizer inlet 4. Main steam

Sodium analysis and recording shall be provided for:

1. Condensate pump discharge

373

2. Condenser hotwell 3. Condensate polisher outlet 4. Economizer inlet 5. Main steam 6. Boiler blowdown

Hydrazine analysis and recording shall be provided for the economizer inlet and auxiliary boiler feedwater.

Chemical feed - Cooling water

The scope of this equipment includes the cooling water conditioning feed system which will consist of a feed tank with mixer and dosing pumps all mounted on a skid along with piping, valves, fittings, welding instrumentation and controls, hungers and supports.

Adequate space and means for maintaining the equipment shall be provided. as well as for controlling containing and treating of spills.

The cooling water chemical feed equipment shall be arranged to provide corrosion inhibitor feed to the cooling water system.

According to the bidder’s design of the cooling system the quality of the cooling water has to prevent negative effects by fouling and scale deposits.

Necessary equipment for treatment of make-up water or dosing of scale inhibitors are within the scope of supply and services of the bidder.

A detailed technical description of the system and the proposed treatment equipment has be submitted with the tender documents.

6.2.7 Condensate treatment system

The scope of this equipment includes a condensate treatment system complete with cartridge filters manually operated by-pass associated piping, pneumatically operated valves and cartridges, ion exchanger line designed for treatment of condensate flow rate of 3 x 50%, with cation and anion ion exchangers, regeneration station, regeneration water pumps, associated piping and pneumatically operated valves for full automatic operation and regeneration.

6.2.8 Potable and service water system

Station potable water shall be produced by adding chlorine to filtered raw water from the raw water system and storing it in a potable water storage tank (1 x 500M3). The scope of this equipment includes the potable water storage tank sized to cover necessary storage capacity of power plant water and associated housing complex demand 2 x 100% water supply pumps complete piping system to all potable water consumers.

374

The quality of potable water shall be further adjusted if required to ensure that the water has a slightly positive Langelier Saturation Index and is non-corrosive.

6.2.9 Waste water treatment systems

The scope of this system includes the chemical wastewater collection and treatment system.

The chemical wastewater collection and treatment system (chemical drain) shall consist of sump- pumps for following areas

• water treatment plant • chemical storage • chemical unloading station • floor drain at main machine sets • floor drain at boiler area • stack drain • battery room.

a complete piping system for chemical drain an intermediate storage basin or tank sized to collect waste water out of above mentioned areas ( storage capacity shall be 24 h of station waste water production) neutralization' and treatment tank for treatment of waste water with agitator pH control and dosing units tn neutralize waste water with HCl and NaOH dosing of FeCI3 and flocculent, settlement tank, sludge treatment and nil necessary equipment for treatment, monitoring and measuring or waste Water treatment including remote control devices, piping and electrical equipment.

The wastewater output of the ion exchanger plant and Leakage from the regeneration station shall be fed into the chemical drain system. In addition any chemicals escaping from the indoor or outdoor chemical preparation and storage plant in the event of leakages are also to be led to the chemical drains.

The pre-treated chemical polluted wastewater shall be discharged to the ash pond.

All waste water discharge to the environment shall comply with the Environmental Quality Standard of Bangladesh. Annex shows the relevant standard values effluent. Additional equipment to comply with these regulations shall be considered in the scope or supply and services.

6.2.10 Chlorination system

The scope of this system includes the chlorine feed system to chlorinate the cooling water of Power Plant at the cooling water towers and to chlorinate the potable water system. One (01) sodium hypochlorite (Naocl) plant (free chlorine concentration shall be minimum 1%) having minimum capacity 10 ton/ day shall have to be provided.

375

6.2.11 Laboratory

The laboratory installations and equipment shall be installed for routine control of

• service water • water-steam-condensate water • waste water and • coal and ash • oil

in a coal fired power plant.

The scope of supply, installation, testing, commissioning comprises all necessary supplies and services even if no special reference is made to these.

The instruments and equipment to be delivered shall be as up-to-date. The laboratory shall be designed in accordance with general safety stipulations.

Analysis

The scope of supply, installation, testing, commissioning shall include all necessary equipment to analyse the parameters of a Coal fired thermal power plant.

Laboratory instruments

The laboratory equipment shall comprise all instruments and apparatus necessary for the analytical investigations including all necessary accessories. All programmable instrumental computers must be maintained English version software. Minimum requirements for instruments and apparatus are as follows: Sl.

No

Name of instruments Quantity Remarks

1 Atomic Absorption

Spectrophotometer (AAS)

01 (one) pc Complete set with spare

2 Spectrophotometer (Digital) 01 (one) pc Complete set with spare

3 Spectrophotometer (Analog) 02 (two) pcs Complete set with spare

for each

4 pH meters (Digital) 03 (three) pcs Complete set with spare

for each

5 Electrical micro balance (Digital) 02 (two) pcs Complete set with spare

for each

6 Electrical Conductivity meters

(Digital)

03 (three) pcs Complete set with spare

for each

7 Electrical balances (Digital) 03 (three) pcs Complete set with spare

for each

8 BOD meter (Digital) 02 (two) pcs Complete set with spare

for each

9 COD meter (Digital) 02 (two) pcs Complete set with spare

for each

376

Sl.

No

Name of instruments Quantity Remarks

10 DO meter (Digital) ppb level. 02 (two) pcs Complete set with spare

for each

11 Oil Centrifuge machine (3000 rpm) 02 (two) pcs 100 pcs test tube (100ml

label marking) with

spares

12 Flash point testing device (Open cup) 02 (two) pcs Complete set with spare

for each

13 Flash point testing device (Closed

cup)

02 (two) pcs Complete set with spare

for each

14 Di-electric constant tester for oil

analysis.

01(one) pc Complete set with spare

for each

15 Electric Furnace with temperature

regulator


for each

16 Electric Oven with temperature

control


for each

17 Distillation apparatus (ASTM

method)


for each

18 Ion selective meter (Digital) 02 (two) pcs Complete set with spare

for each

19 Pour pointer 02 (two) pcs Complete set with spare

for each

20 Electron Microscope 01(one) pc Complete set with spare

21 Contamic kit (for oil sediment test) 01(one) pc Complete set with spare

22 Decicator (big size) 04 (four) pcs Complete set with spare

23 Incubator 01(one) pc Complete set with spare

24 Autoclave 01(one) pc Complete set with spare

25 Computer (Inter Core two dual Core) 01(one) pc Complete set with spare

26 Temperature meter (for pump motor) 02 (two) pcs Complete set with spare

for each

27 Coal crusher (For laboratory analysis) 01(one) pc Complete set with spare

28 Coal disintegrator machine with sieve 01(one) pc Complete set with spare

29 Specific gravity meter (0.4 to 2.0) 02 (two) pcs Complete set

30 Viscometer with oil temperate

regulator


31 Refrigerator (14 cft) 01(one) pc Complete set with spare

32 Electric heater 01(one) pc Complete set with spare

33 Colorimeter for free chlorine (Cl2)

test.


Chemicals

The types and quantities of chemicals supplied shall he calculated in such a way that all necessary analyses can be carried out to permit uninterrupted laboratory operation.

Normal solutions for titrimetric analysis to be in the form of prefabricated vials for later dilution (type; Merek Titricol or equivalent).

The quantities of all chemicals must be sufficient for the analytical supervision of the power plant during commissioning period, warranty period & LTSA period. The purity of the chemical substances must be in accordance with the requirements of the various analytical methods to be performed.

377

General glassware and tools

This scope of supply, installation, testing, commissioning comprises the complete furnishing of the laboratory plastic/ glassware and safety kids. Minimum requirements are as follows: Sl.

No

Name of plastic/glass wares Quantity Remarks

1 Automatic burette with pipes &

rubber ball

(1 ml, 2 ml, 3 ml, 10 ml, 25 ml)

Each 05 (five) pcs. Good quality, total

twenty five pcs.

2 Eye-protectors 50 (fifty) sets Good quality

3 Rubber thick hand gloves

(Acid/caustic proof)

50 (fifty) sets Good quality

4 Acid/caustic proof apron 15 (fifteen) sets Good quality

5 Musk (Acid/caustic proof) 25 (twenty five)

sets

Good quality

6 Pyrex measuring glass cylinders

(500ml,250ml, 100ml, 50ml)

05 (five) pcs +10

(ten) pcs +10 (ten)

pcs +10 (ten) pcs

Good quality , total

thirty five pcs.

7 Pyrex glass beakers (1000ml,

500ml, 250ml, 100ml, 50m.)

Each 10 (ten) pcs. Good quality , total

fifty pcs.

8 Pyrex glass funnels (5 ml, 10 ml,

20 ml, 25 ml, 50 ml)

Each 05 (five) pcs Good quality, total

twenty five pcs.

9 Reagent glass bottles

(acid/caustic/silica proof) one liter

20 (twenty) pcs Good quality, total

twenty pcs.

10 Reagent glass bottles (light

proof/coloured) one liter and half

liter

06 (six) pcs one

liter + 06 (six) pcs

half liter

Good quality, total

twelve pcs.

11 Pyrex glass volumetric flask

(1000ml, 500ml, 250ml, 100ml,

50ml)

10 (ten) pcs + 10

(ten) pcs +10 (ten)

pcs +10 (ten) pcs

+10 (ten) pcs

Good quality, total

fifty pcs.

12 Plastic beaker (500 ml) 05 (five) pcs. Glass transparent

good quality

13 Plastic type volumetric flask

(250ml, 100ml, 50ml)

Each 10 (ten) pcs. Good quality, total

thirty pcs.

14 Pipette filler 20 (twenty) pcs

different size

Good quality,

twenty pcs.

15 Conical flask with lid (250ml) 20 (twenty) pcs Good quality,

twenty pcs.

16 Conical flask (250ml) 20 (twenty) pcs Good quality,

twenty pcs.

17 Crucible (rectangular) ash test for

coal

20 (twenty) pcs Good quality,

twenty pcs.

18 Crucible with lid (circular) volatile

test for coal


twenty pcs.

19 Crucible with lid (circular) inner

moisture test for coal


twenty pcs.

378

Laboratory furniture

The following laboratory equipment shall be included in the scope of supplies as a minimum:

• work places for wet-chemical work working surfaces proof against chemicals and heat. doors and cabinets in the floor-mounted units with integrated sinks at one end with a swivel-type mixing faucet for cold and warm water and splash wall electrical connection outlets compressed air supply gas supply and water supply

• closed laboratory ventilation hood working surfaces proof against chemicals and heat drawers and cabinets in the floor-mounted unit electrical connections outlets compressed air supply. gas and water supply

• weighing table for the precision analysis balances

• work benches with artificial resin surface for titrimetric analysis. proof against chemicals and heat with drawers and cabinets in the floor-mounted units

• potable water stainless steel connection from existing potable water distribution network to places where water is required .

• complete compressed air distribution network in the laboratory rooms. made of galvanised carbon steel piping from the compressed air system

• complete compressed air reducing and filtering device for oil-free and dust-free

• deminemlised water system

When furnishing the laboratory, there may he no gaps left in the working surfaces. Adequate numbers or control elements for water, electricity, compressed air supplies etc. shall he provided and so arranged that they can be easily operated.

Adequate provision shall be made for storage space liter glass equipment chemicals, etc. and likewise there shall he adequate working surfaces and stowage surfaces for analysis equipment.

Spare parts.

Spare parts for the warranty period and LTSA period are to be included in the price schedules.


The requirements specified in B0.6 under Section 'General Technical Requirements are to apply and. where applicable. furtl;er regulations from the other sections of this specification.

379

The water storage and treatment system shall afford:

• fully automatic operation of single supply and treatment facilities • control from local control panels. Important alarms measurements and

status signals shall be transmitted to the Central Control Room.

6.3.1 Demineralised water treatment plant

The demineralised water treatment plant is to supply make-up water in sufficient quantity for boiler feed-water and for the secondary cooling water systems as well as for other consumers which require high-purity water by demineralisation of raw water. Demineralising shall be done by filtration, RO, decarbonizer and mixed bed exchangers. All common plant items such as pumps. pipes controllers and resin traps are to be designed so that the ion exchanger lines can work in parallel if necessary .

The dual media filter is to remove suspended matter from the raw water to protect the ion exchangers from fouling by mechanical impurities.

The filters shall be designed for automatic backwash cleaning. The backwash water shall be taken from the make-up water main.

Backwashing of the filter shall be started after triggering of a high differential pressure alarm in the local control system of the water treatment plant. The program for backwashing must be time controlled.

The dual media filter is to be provided with differential pressure gauge with adjustable high alarm and 2 (two) sight-glasses.

Sampling facilities are to be provided at all requisite points upstream and downstream of the filters.

Ion exchangers

The exchangers are to be protected internally against corrosion by a 3 mm layer of tough rubber. All rubber lining is to be manufactured by the so-called hot process which means real vulcanization.

The cation and anion exchangers are to be equipped with two (2) sight-glasses one (1) at the upper resin level one (I) in the upper section at the exchanger vessel.

The above mentioned requirement applies for ion exchange vessels with a now rate > 20 m31h. Smaller plants could be constructed with GRP vessels.

The mixed bed exchangers are to be equipped with three (3) sight-glasses. one (1) at the upper resin level, one (1) in the upper section at the exchanger vessel and one (1) at the level of the resin interface .

380

The exchanger resins selected must have a high resistance to fouling.

The number of nozzles in the exchangers shall be at least 80 per m2.

The ion exchangers are to be equipped with a fully automatic system enabling the regeneration cycle to be started and to run fully automatically in response to operation by the water treatment operator.

The control system must provide the following programs:

• Starting • Stopping • Selection of a particular step and • Repeat of each step of the program

The individual steps of the program e.g. backwashing, introduction of acid, rinsing acid etc. must be indicated on the local control panel by means of process graphic displays and specially designed control displays.

The program sequence shall stop at predetermined points in order that the operator may check, for example, that the mixed bed resins have separated or mixed correctly.

The program must stop when regeneration has finished. The line, which has been regenerated is to be brought back into operation by a control action from the water treatment local control room.

The correct position and actual position of the various valves for each stage of the program must be monitored automatically. In the event of a fault, the program must stop and the fault indicated on the local control panel. An alarm must also be given. if the operating programme is not completed within a given time. Suitable precautions must be taken to ensure that no switching errors can occur and no critical situation may arise in the case of voltage or compressed air failures.

The operation or the demineralisation plant shall be controlled by continuously measured indicated and recorded conductivity readings downstream of the anion and mixed bed exchangers.

Regeneration (end or the service cycle) of the mixed bed exchanger shall be initiated based on first occurrence of anyone of the following:

• High conductivity in the effluent • High silica in the efl1uent • Pre-set volume or time has been reached • High differential pressure across the resin bed

Sampling facilities are to be provided at all requisite points upstream and downstream of the ion exchangers.

381

Special consideration has to be given to the corrosion protection of all surfaces coming into contact with HCL .

Protective double block and bleed valving shall be installed where necessary to prevent, contamination of the various media. as a minimum at the following points:

• Downstream of the regenerating pumps • in the regenerating pipelines before each mixed bed filter

The dilution (regeneration) water lines are to be equipped with flow meters.

Waste water, chemicals spilling and leakages

The wastewater output of the ion exchanger plant and leakage from the regeneration station shall be fed into the chemical drain system. In addition, any chemicals escaping from the indoor or outdoor chemical preparation and storage plant in the event of leakages are also to be led to the chemical drains.

6.3.2 Conditioning plants

The dosing units shall be fully skid-mounted units. The concentrated chemicals ammonia and hydrazine supplied shall be diluted to a 1 to 2% solution by mixing with demineralised water. The solid phosphate shall be diluted to a 3 to 5% solution in a separate mixing and dosing station.

Dosing pumps shall be of the reciprocating metering type

Appropriate piping or adsorption devices of the ammonia conditioning station shall ensure no ammonia gas leakage.

The dosing station for hydrazine shall be designed and erected in full compliance with regulations for storage and handling of hazardous substances.

6.3.3 Condensate treatment plant

The specified requirements for ion exchangers of demineralization plant are to be applied also for the condensate treatment plant.

Regeneration (end of the service cycle) of the ion exchanger shall be initiated based on first occurrence of anyone of the following:

• High conductivity in the effluent • Pre-set volume or time has been reached • High differential pressure across the resin bed

The cartridge tilters are to be provided with differential pressure gauge

382

with adjustable high alarm.


The following technical schedules comprise part of this specification. The data and requirements specified in the respective forms are to adhered to and the missing data of forms are to be completely tilled in. The completed technical schedules are to be submitted with the Bid.

383


B6: Water Storage and Treatment Systems

Technieal Data by Bidder Unit Data

Cooling water system

Cooling water production capacity m3 / hr Number of Settling water tank no. Each Settling water tank capacity m3 Number of Clear water tank no. Each Clear water tank capacity m3 No. of other tanks (if required) no.

Capacity of other tanks, each m3

Number of coal slury tank no.

Each coal slury tank capacity m3

No. of clarifiers no.

Capacity of each clarifier m3 / hr

Type of other filters -

No. of coal mine discharge water receiving pumps no.

Capacity of each coal mine discharge water receiving pump

m3 / hr

No. of Cooling water supply (makeup) pumps no.

Capacity of each Cooling water supply (makeup) pump m3 / hr

Potable water storage

Number of tanks No. Net capacity m3 Material

Potable water pumps

Number of pumps No. Rate of delivery m3/h Power consumption at coupling kW

Material: Housing/impeller -

. Chlorine dosing system potable water .

Type of dosing equipment

Chlorine dosing system cooling water system

Type of dosing equipment

B6/FD-1

384




Raw water storage (from existing deep tube well water)

Number of tanks No.

Net capacity m3

Material -

Raw water pumps

Number of pumps No.

Rate of delivery m3/h

Power consumption at coupling kW

Material: Housing/impeller

Raw water pumps (other consumers)

Number of pumps No.



Material: Housing/impeller

Clear water storage

Number of tanks No.

Each tank Net capacity m3/h

Material

Demineralisation water plant

Number of lines No.

Net continuous flow rate each line m3/h

Net treated water volume per cycle each line m3

Cycle length h

Regeneration time h

Regeneration mode

Chemical consumption

• HCI 100% each line kg/cycle

• NaOH 100% each line Total kg/cycle

waste water discharged m3/cycle

Quality of treated water:

• Conductivity µS/cm

• Silica mg/I

B6/FD-2

385




Dual media filter

Number of filters No.

Throughput: Minimum/Maximum m3 /h

Material .

Diameter mm

Cyl. jacket length mm

Total height mm

Number of air blowers No.

Rate of delivery N m3 /h

Degasifier No.

Number of unils Throughput: m3 /h

Number of pumps No.

Flow rale of pumps / Delivery head m3 /h / bar

Diameter of degasirier lower

Height mm

Material tower mm

Number of air blowers .

Rate of delivery No.

Mixed bed exchanger

Number of mixed bed exchangers No. Throughput: Minimum/Maximum m3/h

Exchanger capacity: Cation eq

Anion eq

Operating capacity of cation resin eq/IE of anion resin eq/IE

Exchanger material quantity Cation I Anion I

Velocity of operation flow (min.lmax.) m/h

Velocity of backwash riow m/h

Design pressure bar Diameter mm Cyl. jacket mm

length Total mm height mm

B6/FD-3

386




Ion exchange washing unit

Number of units No. Volume tank

Material: I

Regeneration station for hydrochloric acid

Number of regeneration stations No.

Number of pumps No.

Type of pump

Rate of delivery I/h

Material .

Concentration of diluted acid for regeneration % Volume of dosing tank I

B6/FD-4

387




Regeneration station for caustic soda


Number of pumps No.

Type of pump


Material -

Concentration of diluted acid for regeneration %

Volume of dosing tank I

Pump for. regeneration water

Number of pumps No.




Air blower

Number of blowers No.

Rate of delivery Nm3/h

Delivery head Bar


Pump for make-up water

Number of pumps No.


Power consumption at coupling' kW


Demineralised water storage tank

Number of tanks No.

Each tank net capacity m3

Diameter mm

Cylindrical height mm

Material: .

B6/FD-5

388




Chemical handling

Hydrochloric acid system

Number of storage tanks No.

Capacity mJ

Diameter/cy!. height mm

Material

Caustic soda system

Number of storage tanks No.

Capacity mJ


Material

Waste water treatment system

Sump pumps

Number of sump pumps No.

Pumping rate m3/h

Material

Intermediate storage basin/tank

Capacity

Material

Diameter/cy!. height or length/width/height mm

Discharge pump

Number of pumps No.

Pumping rate m3/h

Power consumption at coupling. kW

Malerial

Neutralisation tank

Number of tanks No.

Capacity mJ


Material -

Power consumption agitator kW

B6/FD-6

389




Discharge pump

Number of pumps No.

Pumping rate m3/h


Material

Settling tank

Number of tanks No.

Capacity m'

Surface area m2

Material �

Sludge dewatering

Type of sludge dewatering �

Conditioning station

Medium: Ammonia solution

Number of dosing stations No.

Capacity of dosing tank m'

Material: Tank �

Agitator -

Pipes, Valves -

Number of dosing pumps No.

Pumping head bar

Pumping rate variable from - to I/h

Material: Head/Piston / Diaphragm -

Medium: Hydrazin


Number of dosing tanks No.

Capacity of dosing tanks m'

Material: Tank -

Pipes, Valves -


Pumping rate variable from - to l/h

Material: Head/Piston -

B6/FD-7

390




Medium: Trisodiumphosphate


Number of dissolving tanks No.

Capacity of dissolving tanks m3

Material: Tank �

Agitator �

Number of transfer pumps No

Rate of delivery m3 /h

Material:

Number of lifting and tipping devices No.

Capacity of dosing lank m'

Material:' Tank

Pipes. Valves


Pumping rate variable from - to I /h

Material: Head/Piston

Diaphragm

Medium: corrosion inhibitor


Number of dissolving tanks No.

Capacity of dissolving tanks m3

Material: Tank

Agitator

Number of transfer pumps No.


Material:

Number of lifting and tipping devices No.

Capacity of dosing tank m3

Material: Tank

Pipes, Valves


Pumping rate variable from - to I/h

Material: Head/Piston

Diaphragm

B6/FD-8

391




Condensate system

Net treated water volume per cycle of each ion exchanger line m3

Chemical consumption: h

Regeneration time h

Regeneration mode

Chemical consumption:

• HCI 100% each line kg/cycle

• NaOH 100% each line kg/cycle

Total waste water discharged m3/cycle

Quality of treated water:

conductivity µS/cm

Cartridge filter

Number of filters No.

Throughput: m3/h

Material

Type and material of cartridge

Cation exchanger

Number of exchangers No.

Throughput: Minimum/Maximum m3/h

Exchanger capacity: eq

Exchanger material quantity l

Total exchange capacity max. eq/IE

Velocity of operation flow (min./ max.) m/h

Velocity of backwash flow m/h

Design pressure bar

Diameter mm


Total height mm

Anion exchanger

Number of exchangers No.

Throughput: Minimum/Maximum m3/h

Exchanger capacity eq

Exchanger material quantity I

B6/FD-9

392

8PDB, 8arapukurla Power Plant Bidder/Contractor

86: Water Storage and Treatment Systems


Anion exchanger

Total exchange capacity max. eq/IE

Velocity of operation flow (min./ max.) m/h

Velocity of backwash flow m/h

Design pressure bar

Diameter mm


Total height mm

Regeneration station for hydrochloric acid


Number of pumps No.

Type of pump


Material - Concentration of diluted acid for regeneration %

Volume of dosing tank I

Regeneration station for caustic soda Number of regeneration stations No.

Number of pumps No.

Type of pump


Material . Concentration of diluted acid for regeneration %

Volume of dosing tank l

Pump for regeneration water

Number of pumps No.

Rate of delivery m'/h



B6/FD-10

393

Barapukuria 250MW Coal mine specifications

Documents

general requirements

general conditions

general technical requirements

protection of plant

general auxiliary systems

b0 general specification

design requirements

emission standards