9HX237380-003-001_GED 20MW Process description REV B.pdf

GED RUBBER WOOD FIRED

POWER PLANT

DOC TITLE Process Description

DOC NO. 9HX237380-003-001 Rev B Page No. 1 of 24

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GED Rubber Wood Fired Power Plant

Process Description

Pyry Energy Ltd. Vanit II Bldg, 22nd Floor, Room#2202

1126/2 New Petchburi Road Makkasan, Rajchthewi TH-10400 BANGKOK

Thailand

B 17 Oct 2014 Issued as per comment CRS MU MN

A 15 Sep 2014 Issued for Preliminary CRS MU MN

Rev Date Description Prepared Checked Approved Authorized


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Copyright Pyry Energy Ltd.

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REVISION HISTORY

Rev No. Date Detailed revision description

A 15 Sep 2014 Issued for Preliminary

B 17 Oct 2014 Issued as per comment


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TABLE OF CONTENTS

Clause Page

1 PURPOSE OF THIS DOCUMENT 6

2 GENERAL DESIGN DESCRIPTION 6

2.1 Reference Design Conditions 7

2.2 Design Life 9

2.3 Plant Operation 9

3. PROCESS DESCRIPTION OF INDIVIDUAL SYSTEMS 10

3.1 Fuel Receiving, Processing, Storage and Fuel Feeding System 10

3.1.1 Fuel Receiving Facility 10

3.1.2 Fuel Unloading and Storage 10

3.1.3 Fuel Processing Facility 10

3.1.4 Processed Fuel Storage 11

3.1.5 Fuel Feeding System 11

3.2 Steam Systems Description 11

3.2.1 Boiler 12

3.2.2 Main Steam System 12

3.2.3 Steam Turbine 12

3.2.4 Steam Admission 13

3.2.5 Steam Turbine Sealing Steam System 13

3.2.6 Steam Turbine Ejector System 13


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3.2.7 Steam Turbine Condenser 13

3.3 Water Steam Cycle/Balance Of Plant 14

3.3.1 Steam Bypass System 14

3.3.2 Startup Vent Valves 14

3.4 Water Treatment And Water Supply System 14

3.4.1 Raw Water Supply 15

3.4.2 Service Water System 15

3.4.3 Potable Water System 16

3.4.4 Condensate System 16

3.4.5 Feedwater System 16

3.4.6 Feedwater Deaeration 16

3.4.7 Feedwater Pumps 17

3.4.8 Blowdown 17

3.5 Flue Gas Cleaning System - Electrostatic Precipitator (ESP) 17

3.6 Ash And Dust Handling System 18

3.7 Chemical Storage and Dosing Systems 18

3.7.1 Boiler Chemical Dosing 18

3.8 Cooling Tower Chemical Dosing 19

3.9 Compressed Air System 19

3.10 Cooling Water Systems 19

3.10.1 Main Cooling Water Systems 19

3.10.2 Auxiliary Cooling Water Systems / Closed cooling water Systems 20


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3.11 Waste Water Treatment / Neutralization System 20

3.12 Fire Protection and Detection System 21

3.13 Steam and Water Sampling System 22

3.14 Plant Control System 22

3.14.1 General Description 22

3.14.2 Plant Control Concept 23

ATTACHMENTS:

None


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1 PURPOSE OF THIS DOCUMENT

The purpose of this document is to provide an overview of the conceptual design of power plant and description of process including functionality of major subsystems and the major components utilized within the power plant.

This document does not intend to give a detailed technical description of all components within the power plant with their design features and design considerations. For this level of detail we refer to the individual design documents and calculations which will be issued throughout the design phase of the power plants.

This document to reference with process flow diagram document No. 9HX237380-000-001

2 GENERAL DESIGN DESCRIPTION

Gulf Energy Development (GED) is planned to construct a 20 MW (net) power plant in Songkla province of Thailand. The Power Plant shall produce net 20 MW electricity which will be supplied under the SPP guidelines to the PEA Grid. The Plant design is based on a configuration of one boiler, one steam turbine generator and associated balance of plant. The following systems, major equipment and facilities are envisaged:

Boiler.

Main Steam System including turbine bypass.

Steam Turbine Generator.

Condensate System.

Feed Water System.

Boiler Air and Flue Gas System.

Electrostatic Precipitators.

Ash and Dust Handling System.

Cooling Water Systems including Cooling Tower.

Chemical Storage and Dosing System.

Plant and Instrument Air Systems.

Fuel receiving, processing, storage and fuel feeding system including mobile equipment for fuel handling.

Raw Water System including River Intake System and Raw Water Pipeline.

Water Treatment Plant including Demineralization Plant.

Service Water System.

Potable Water System.

Fire Protection and Detection System.

Wastewater drainage, treatment and recovery systems.

Storm water Drainage.


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Roads and pavements.

Buildings including Plant Control Room, Workshop and warehouse, office, etc.

115 kV Switchyard.

Electrical System including Medium Voltage and Low Voltage Systems, electrical protection, DC/UPS System, earthing, area lighting, etc.

Electrical room housing MV and LV switchboards, MCC, control and protection equipment, UPS, etc..

DCS based Integrated Control and Monitoring system (ICMS).

Steam and Water Sampling System.

2.1 Reference Design Conditions

The design shall be based on the following design conditions:

(1) Ambient Condition for Performance Guarantee

a) Ambient Pressure 1,009 mbar

b) Design Dry Bulb Temperature 32.8 deg C

c) Design Relative Humidity

78 %

(2) Ambient Temperature

a) Maximum Ambient Dry Bulb Temperature 38.2 deg C

b) Minimum Ambient Dry Bulb Temperature 19.7 deg C

c) Design Temperature for Electrical 32.8 deg C

(3) Relative Humidity

a) Maximum Relative Humidity 90 %

b) Minimum Relative Humidity 65 %

c) Design Relative Humidity 77 %

(4) Rainfall


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a) Annual Rainfall 1685 mm

b) 1 Hour Rainfall 85 mm

c) 15 Minute Rainfall 145 mm

(5) Wind speed (3 SecondGUST) 38 m/s

(6) Air Quality Slightly saline

(7) Site Level TBA

(8) Seismic Condition DPT.1302-52 and

ASCE7-05

(9) Noise Level < 85dB(A) at 1m from the

equipment

(10) Power Source

a) Frequency 50 Hz

b) Range of Frequency -1 % to +1 %

c) Motor power (=> 200kW) 6.6 kV, 3-phase

d) Motor power (< 200kW) 400/230 V, 3-phase

e) Lighting 230 V, 1-phase

f) Instrumentation 230 V, 1-phase

g) Control, Protection & Indication 220 V DC

(11) Motor

a) Protection Degree, Motor and Junction Box IP 54 for Indoor


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IP 55 for outdoor

b) Winding Insulation Class F

c) Temperature Rise Class B

The Plant shall be designed for the full range of the ambient air conditions presented in this table.

2.2 Design Life

The Works shall be designed for a minimum operational life of 25 years.

2.3 Plant Operation

Overall, the operational strategy is to design and construct the Works for continuous operation. During the normal operation, the plant is running mainly at base load in peak period and at about 65% in off peak period (night time). The works shall be designed for operation in excess of 8000 hours per year (availability guarantee is given separately). Even the works is expected to operate mainly on maximum load; it shall be possible to operate the works continuously in all load points of the capacity between the minimum and maximum loads. During the design lifetime (200,000 hours), the works shall be designed to safe and efficient start-up from hot, warm and cold conditions without exceeding permissible levels of stress within components. It is of utmost importance that the technical solutions used in the process shall secure energy production in an environmentally safe way and with highest possible thermal efficiency. The works shall be suitable for remote automatic /manual operation from a control room by means of a proven microprocessor based, functionally grouped and hierarchically structured control and information system (DCS). Full sequence control shall be provided to facilitate automatic start up and shut down of the units and their auxiliary systems with minimum plant attendance.


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3. PROCESS DESCRIPTION OF INDIVIDUAL SYSTEMS

3.1 Fuel Receiving, Processing, Storage and Fuel Feeding System

Rubber wood stumps will be transported from the areas of plantation by trucks (provided by

others) to the site.

3.1.1 Fuel Receiving Facility

The receiving facility will be purpose-built to suit the following criteria:

Each truck shall be weighed before and after the wood is unloaded.

It is expected that approximately 50 trucks will deliver fuel each day.

The facility will be open to accept deliveries seven days a week between the hours of 7 am and 7 pm.

Each truck can carry up to 20 metric tons of wood.

The facility shall suit weighing and unloading from a trailer truck.

3.1.2 Fuel Unloading and Storage

The fuel yard will be located within the Plants security fence with dedicated access. The wood

from the trucks shall be unloaded from trucks and stored in the open yard using mobile

equipment. The unloading and storage facility shall be purpose-built to suit the following

criteria:

The fuel yard shall be sized to hold the fuel required for 14 days with the boiler operating at Maximum Continuous Rating.

The wood shall be stacked in a way that would allow natural drying.

The ground storing the tree stumps will be asphaltic concrete 50 mm thk. pavement.

The stock-piling arrangement will facilitate easy loading of stumps for cleaning.

The mobile equipment used for stacking and un-stacking will be fit for the requirements stated above.

3.1.3 Fuel Processing Facility

This facility will receive wood from the open storage yard and clean and process the wood to

produce chips meeting the fuel size specification. Stumps will be picked using mobile

equipment and be cut in smaller size before chipping. Raw wood will be fed by passing


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through disc screen to remove sand /stone before chipper. Then wood chipper will cut the raw

wood into specific chip size as processed wood chip and forwarded to processed fuel storage

area. Fuel processing facility shall be concrete pavement with roof shed at wood chipper to

protect from rain.

3.1.4 Processed Fuel Storage

The processed fuel storage building shall be sized to hold a 3 days fuel supply to the boiler.

The wood chip will be stored in enclosed building to prevent contamination of fuel with soil,

rock or stones and rain. The building includes with natural roof ventilation for wood

dehumidification and prevents dust hazards. This area will be sized to contain fuel

requirements of the boil at MCR condition. This area may be divided into two sections to allow

storage and reclaiming simultaneously.

3.1.5 Fuel Feeding System

The wood chips will be reclaimed from the storage area and transferred to a reclaiming hopper

pit. The fuel hopper will be suitable for receiving wood chips from self-unloading trailers, dump

trucks, front-end loaders or conveyors. The fuel feeding system will be equipped with tramp

metal separators.

The wood chips from the reclaiming hopper will be conveyed to a surge silo from which wood

chips will be conveyed to a day bin which can store 6-hour fuel requirements of the boiler at

MCR conditions. The wood chips from the day bin will be metered and fed to the boiler by

screw feeders.

3.2 Steam Systems Description

The entire system process flow is a complete system of water and steam recirculation

process.

The super-heated steam from boiler after heat exchanging enters into steam turbine to drive

turbine and generator to generate power. The steam after driving turbine will be cooled down

into water in the condenser. The feed water will enter into boilers economizers for heating up

through feed water pump. The high temperature water after heating up economizer. Feed

water then mixes with the saturated liquid in the steam drum and the steam/water mixture


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rising from the generating circuits and enters into the steam turbines. Consumed water can be

made up by the demineralized water from demineralizer at circulation process.

3.2.1 Boiler

Boilers are pressure vessels designed to produce high pressure steam in which water under pressure is transformed into steam by the application of heat. In the boiler furnace, the chemical energy in the fuel is converted into heat, and it is the function of the boiler to transfer

this heat to the contained water in the most efficient manner.

A boiler to absorb the maximum amount of heat released in the process of combustion. This

heat is transferred to the boiler water through radiation, conduction and convection.

The rubber wood fuel is transferred into the combustion system by biomass feeding. From the combustion system the hot gasses pass through the boiler and super heater for heat energy transfer.

Steam is fed form the collecting steam drum to the steam turbine generator. The turbine turns a generator through a reduction gear set. Exhaust steam is condensed and routed through the

boiler feed water systems and then pumped to the economizer.

Refer to Technical Specification for Rubber Wood Fired Boiler.

3.2.2 Main Steam System

From the boilers, the main steam with the main steam supply will go through the main steam

pipe and the main steam stop valve, and the governor main valve before entering the steam

turbine.

In order to achieve convenient normal operation and emergency start and stop there is a main

steam bypass system and piping. When the pressure exceeds the settling value of the main

steam governor valve, it will automatically open partly and the excessive steam can directly

enter into the main condenser, to keep the pressure of turbine inlet constantly. After the De-

superheater the steam pipe is connected to the condenser.

3.2.3 Steam Turbine

Refer to Technical Specification for Rubber Wood Fired Steam Turbine.


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3.2.4 Steam Admission

The HP steam enters the HP turbine by one HP Steam inlet line. At the inlet of the steam turbine a main stream stop valve is installed to interrupt the steam supply in case of a steam turbine trip.

3.2.5 Steam Turbine Sealing Steam System

For sealing purposes of the steam turbine, HP steam from the common HP steam line is supplied to the steam turbine glands during start-up/shut-down. During low load operation the sealing steam is supplied by the steam turbine bleed (extraction) steam system. The sealing steam is controlled at a slight over-pressure by a pressure reducing control valve. The vacuum side of the steam turbine glands is kept at a pressure below atmospheric by one (1) 100% ejector steam condenser. The gland steam is condensed in the ejector steam condenser by the main condensate water and the drain is fed to condenser hot well.

3.2.6 Steam Turbine Ejector System

The vacuum in the condenser is being established and maintained by the ejector steam system. The initial vacuum is being established by the startup ejector. After initial vacuum the normal ejector will take over and will establish the operational vacuum pressure.

3.2.7 Steam Turbine Condenser

The condenser is horizontally arranged water cooled surface type to transfer heat from ST

Exhaust steam to the cooling water to condensate the steam coming out of the steam turbine.

Also steam turbine bypass valves lines are connected to exhaust transmission duct between

ST exhaust and condenser to condense the steam in the condenser during start up, shutdown

and emergency case. A condenser LP flash box to collect ST starting drains is installed. A

condensate water recirculation pipe to keep minimum flow rate through the condensate

extraction pumps is connected to the condenser.

A demin water make-up line is connected to the condenser hot well to make up for the losses

of the water/steam cycle. These losses consist of start-up losses, Boiler blowdown losses or

export steam condensate return losses in case the export steam condensate is off

specification.


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3.3 Water Steam Cycle/Balance Of Plant

3.3.1 Steam Bypass System

A steam turbine bypass system is incorporated in the design to maximize operation and start

up flexibility of the plant. The proposed capacity of the turbine bypass valve is 60% of the main

steam flow at the boilers maximum continuous rating. The bypass system will be operated in

the following cases:

- Start-up and shutdown after vacuum has been established in the steam turbine

condenser.

- To prevent boiler tripping, when the steam turbine trips.

- High pressure at the inlet of the steam turbine in the steam lines.

Each individual bypass system consists of a steam stop valve, a pressure reducing station and

spray water control valve and spray station (integrated in the pressure control valve).

Downstream of the spray station a temperature transmitter is installed to alarm in case of

malfunction of the spray station. The water for the spray station is taken from the main

condensate line, immediately downstream of the condensate pumps.

3.3.2 Startup Vent Valves

When the power plant is started from cold conditions no vacuum can be established in the

system turbine condenser. In order to assure steam flow through the Boiler systems and

prevent overheating of the boiler tubes, a HP start up vent valve is installed in the HP steam

lines. The start-up vent valves will be used during initial warm up and these valves will control

the pressurization of the Boiler HP systems until the steam turbine condenser has established

vacuum and the bypass stations have been released for control. When the bypass stations

have been released for control, the start-up vent vales will be closed and the bypass station

takes over the pressurization of the boiler systems.

3.4 Water Treatment And Water Supply System

The overall objective of boiler feed water treatment is generally to reduce the hardness, the silica or the total dissolved salts concentration in the feed water. Because the processes that achieve this, (for example ion exchange) can themselves be fouled by some raw water


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contaminants, it is normally also necessary to pre-treat the raw water before it enters the boiler feed water treatment system. Typically, the treatment processes are required to remove the following types of contaminants: The water treatment plant consists of pre-treatment and a demineralization plant to treat raw

water to the quality required by the boiler.

Raw water first flows into conventional clarifiers. The clarified water will be stored in a clarified

water tank and will be used as process water and feed to the demineralization plant. For the

production of demineralization water, the clarified water will be pumped to a sand filter for

removal of residual suspended solids and to the granular activated carbon filter for removal of

organic constituents.

Dissolved solids are removed by the demineralization plant. Demineralization plant consists of

cationic and anionic exchangers. Demineralized water is further polished by mixed bed

exchangers before been stored in the demineralized water storage tank. The consumers of the

demin water are:

-The condenser for cycle make-up.

-Deaerator.

-Boiler chemical dosing skid.

-Closed cooling water head tank for CCW system.

-Laboratory and regen water by demineralized water pumps.

The regular consumer is the condenser make up system where the steam cycle losses adding

demin water to the condenser. Other consumers are minor.

3.4.1 Raw Water Supply

Raw water is drawn from the river situated from the plant.

2x100% raw water intake pumps are provided to extract the water from the river to a raw water

pond via a pipeline. The raw water is pumped into clarifier from the raw water pond. Raw water

is used for firefighting. Fire water pumps discharge raw water to the firewater ring main.

3.4.2 Service Water System

A service water distribution system is provided in the Plant. Water from the raw water pre-

treatment plant is used for service water. The output of the pre-treatment plant is stored in the


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service water tank 2 x 100% Service water pumps supply service water for washing and

cleaning purposes in the plant. 2 x 100% Make-up water pumps supply make-up water to the

cooling tower.

3.4.3 Potable Water System

A potable water system is provided to supply water for drinking and eye wash showers. The

principal methods of disinfection are irradiation by ultra-violet light. Ultraviolet (UV) light kills

micro-organisms by short-wave light that destroys their molecular structure.

3.4.4 Condensate System

The turbine exhaust steam flows to a shell and tube condenser vessel where heat is rejected

via cooling water flowing through the tubes. Condensing steam collects in the bottom of the

condenser vessel the hotwell. The Condenser hotwell forms a reservoir for the condensate

extraction pumps. Various flows from the steam and water circuit (e.g. gland steam, turbine

drains, CEP min flow, etc) are returned to the condenser to conserve heat and prevent water

leakage from the system. No condenser tube cleaning system is proposed as the cooling

water is clarified river water and is chemically dosed to prevent biological growth and scaling.

Condensate is pumped from the Condenser to the Deaerator by 2 x 100% Condensate

Extraction Pumps, via a Gland Steam Condenser and Low Pressure Heater. The LP Heater is

a shell and tube heat exchanger which obtains steam from the steam turbine. The condensate

from the LP Heater is drained to the Condenser. The gland steam condenser is a shell and

tube heat exchanger which collects and condenses the gland steam from the turbine seals.

A vacuum skid extracts air from the condenser during start-up, and helps to maintain

condenser vacuum during operation. The vacuum in the condenser is established and

maintained by the steam ejectors.

3.4.5 Feedwater System

Condensate from LP Heater flows to a Deaerator.

3.4.6 Feedwater Deaeration

The system consists of a feedwater deaerator and feedwater tank. It has the following tasks:


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Buffer tank for compensating the relatively short-time mass flow fluctuations between feed water demand and condensate return flow (start-up of the plant or steam turbine trip, process condensate losses),

Deaeration of the returned condensate and make-up feedwater, i.e. expulsion of entrapped oxygen and other non-condensable gases,

Feedwater heating.

The water level in the deaerator is automatically regulated by the plant control system.

The design uses sprays of steam and bubbles of steam in the water to extend the steam water

interface and achieve the necessary steam/water contact. Steam is supplied from the turbine

bleed while condensate is supplied from the steam turbine condenser via the LP feedwater

heaters.

3.4.7 Feedwater Pumps

The feedwater pump extracts the deaerated feedwater from the feedwater storage tank and

feeds it to the economiser. A minimum flow device is provided to ensure a minimum flow

through the pump under conditions of minimum or no-flow of feedwater to the boiler.

The drum level of the boiler is kept at a constant value by the feedwater control valve ahead of

the boiler inlet by three-element control.

The multi-stage boiler feed pumps (2 x 100%) complete with leak-off valves, gauges, guards

and couplings will be supplied. Each pump will be provided with a constant speed electric

drive. The pumps are of horizontal, multistage, segment casing design held together by high

tensile tie-bolts.

3.4.8 Blowdown

Boiler water quality is maintained by operation of the continuous and intermittent blowdown

valves. A Blowdown Vessel is provided to receive continuous blowdown. Also, all boiler drains

are connected to blow down tank.

3.5 Flue Gas Cleaning System - Electrostatic Precipitator (ESP)

Electrostatic Precipitators are proposed for fly ash extraction. The gases enter the ESP

horizontally via the inlet, where the gas velocity is evened out over the whole ESP section by

means of a gas distribution system. The ID fan is installed after the ESP.


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On the application of high current, the dust particles are separated on the collecting plate

when passing through the inter electrode spacings.

Both the electrode and the discharge electrode system are cleaned by mechanical, electric-

motor driven rapping devices and thus kept clean. By means of these periodically operating

rapping devices, which are freely programmable for each field with regard to operating and

interval time, the dust is hence loosened due to the shearing forces and falls into the hopper.

3.6 Ash And Dust Handling System

Handling of ash is basically divided into wet bottom ash, dry fly ash. Bottom ash is the material

that is collected beneath the furnace or combustion chamber while fly ash is typically fine dry

ash particles that are suspended in the flue gas and collected at various points downstream of

combustion flue gas path.

The furnace ash handling is a wet system while ash and dust from the economiser/airheater

and emission control is handled by a dry system. Furnace bottom ash falls into the waste

water pit bottom onto a water submerged conveyor that continuously discharges the ash form

the furnace.

A submerged conveyor in circulating water is used to:

- Keep conveyor surfaces cool

- Provide an air-tight seal in the furnace that protects the furnace from air infiltration

- Extinguish any burning or glowing combustion residues

- Lower the temperature of wet ash for convenient disposal external to the boiler

Whilst the dust from the air heater, economiser and ESPs is chain or belt conveyed to an ash

storage silo for disposal by a truck.

3.7 Chemical Storage and Dosing Systems

3.7.1 Boiler Chemical Dosing

One high pressure chemical dosing unit is included, for the intermittent injection of scale inhibitor chemical to the steam drum, and two low pressure pumps for dosing oxygen


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scavenger and ammonia. The dosing system includes pumps, mixing tank (or bulky bins), agitator, instruments and associated valves.

3.8 Cooling Tower Chemical Dosing

The dosing system for the circulating water consists of hypochlorate dosing for preventing

biological growth and Acid pH Control.

3.9 Compressed Air System

The compressed air system comprises of an instrument air system and service air system.

2x100% capacity compressors (1 x duty, 1 x standby) supply air to one air receivers operating in parallel, sized for a five minutes uninterrupted supply of instrument air.

Compressed air from the air receivers passes through two sets of coarse filters meeting the required service air quality. A common air header from the air receivers supplies air to both the instrument air header and the service air header.

Service air is taken directly from the common air header with an actuated isolation valve to isolate the service air header from the instrument air header in event of pressure drop or fluctuation.

Instrument air only is then passed through the refrigerant type air dryer and two sets of secondary (fine) filters to remove any condensed liquids, particulates and oil vapours to ensure air provided is of instrument air quality.

3.10 Cooling Water Systems

3.10.1 Main Cooling Water Systems

The cooling water system is delivering the cooling water to turbine condenser to cool down the

exhaust steam into condensate water, the system is a closed circuit system, the cold water

from goes to the condenser, after cooling process the water is going back to the cooling tower

after temperature rise, where the temperature of the hot water is cooled down to certain level

for continuing the process. Cooling tower water source is taking from raw water pre-treatment

system.

An induced-draught mechanical wet cooling tower system transfers the waste heat of the

water-steam cycle to the atmosphere. The cooling tower consists of two (2) separate cells.


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Two (2) x 50% main cooling water pumps supply the cold water from the cooling tower water

basin to main condenser.

The cooling water quality is controlled by water blowdown through the cooling tower blow down valve. In the main cooling water supply line a pH and a conductivity analyzer are installed for on line monitoring of the cooling water quality. The conductivity measurement is used for the control of the cooling water blow down valve against the conductivity setpoint given by the operator. The pH meter is used for the control loop for dosing acid to control the pH value of the Main Cooling Water.

3.10.2 Auxiliary Cooling Water Systems / Closed cooling water Systems

The main circulating water pumps direct the cooling water to the condenser and the auxiliary

coolers. 2X100% Auxiliary Cooling Water Pumps operate in closed cycle supplying clean,

treated cooling water to the following auxiliary equipment. The auxiliary cooling water pumps

work in a so called duty/standby arrangement. The stand-by pump will start in case of

electrical failures or cooling water pump outlet pressure decreases to certain level.

As the name the closed cooling water system is a separated closed loop system.

The closed cooling water (CCW) system is cooling the following components:

The turbine lubes oil coolers.

The generator air coolers.

The sampling coolers.

Feed pump bearing coolers.

Boiler fan bearing coolers.

Vacuum pump coolers.

ID Fan.

Ash screw cooler.

3.11 Waste Water Treatment / Neutralization System

Waste water from the demineralization plant is combined with drain from boiler blowdown tank

before being routed to a waste water pond.

Within the power plant a 313.2 m3/day waste water pond has been constructed.

This pond collects all waste water streams. These streams are:

- Waste water from Demin plant neutralization basin.


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- Waste water from oil water separator.

- Blow down from cooling tower.

- Treated building waste water.

- Treated oily water.

Two (2) x 100% transfer treated waste water pump have been installed at the transfer treated waste water pit which is connected to the waste water pond through an underground line. To check the quality of the waste water before being discharged to public. When the quality is within the limits the discharge open/close valve opens and the recirculation open/close valve closes and the waste water is being pumped out to public drainage. HDPE sheet lining is provided to prevent environmental impact. The waste water pond may need to provide sub-drainage system with sump pump to prevent floating of HDPE sheet lining in case of high level of ground water which depends on site condition.

3.12 Fire Protection and Detection System

The power plant is equipped with a fire fighting system. For safety and reliable this system

necessary to have the fire water pumps which the purpose. The following pumps have been

installed within the power plant:

- 1 x 100% jockey pump to maintain the pressure in the system.

- 1 x 100% electric motor driven fire water pump.

- 1 x 100% diesel engine driven fire water pump.

The pumps draw their water directly from the raw water pond which sufficient to serve the

highest fire scenario according NFPA 850(highest water demand volume plus 1 set hydrant

operating)

The firefighting water is distributed over the power plant through a ring main pipe distribution

network to the outdoor hydrant stations, the deluge water spray system shall be provide for

main transformers switch yard area , Auxiliary Transformer ,Steam Bearing and fuel oil tank

respectively. The fire hose cabinet shall be provided for indoor building. The firefighting system

is monitored by link the signal from each local panel of fire pump via to the Main Fire Alarm

Control Panel (FACP) which is installed in the control room. The FACP also monitors the

smoke and heat detectors installed at different locations and alarms when a detector is

activated.


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3.13 Steam and Water Sampling System

To ensure the safe and economic operation of biomass boilers and steam turbine generators and to monitor and control the waste gas, waste water. A testing laboratory shall be set up in the plant for chemical analysis and a steam-water online analysis sampling device shall also be set up. All online analysis devices can convert measured data into 4-20mA standard signals which shall be sent to the computers in central control room, to facilitate operators' routing inspection and recording & printing.

The chemical condition of the steam and feedwater system is monitored on-line by means of

the following samples:

Condensate Pump Discharge Conductivity, Cation, Conductivity, pH.

Condensate to Deaerator Conductivity, Cation Conductivity, pH.

Deaerator Outlet Conductivity, Cation Conductivity, pH, Dissolved Oxygen.

Drum Water Conductivity, pH, Sodium, Dissolved Oxygen.

Saturated / Superheated Steam Conductivity, Cation Conductivity.

The steam water analysis system is composed of followings:

High temperature and high pressure rack: Functioned for high pressure steam water temperature/pressure reducing. Includes at least pressure reducing valves, cooler and valves accessories. Low temperature instrument sampling device: Composed of low temperature instrument panel and manual sample rack. Includes at least all components required for sample testing, sampling, alarming, signal transfer, automatic protections, pipelines, electric devices, control instruments and valves. Demin. water cooling device includes heat exchangers, water storage tank and circulation

pumps along with relevant pipelines, pipe fittings, valves. The devices are mounted on a

frame.

3.14 Plant Control System

3.14.1 General Description

The plant control system operates under all conditions such as normal power operation, cold and warm start-up, load rejection, island operation, and shutdown in automatic mode or


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manually controlled by the operators at operator workstations in the Central Control Room (CCR).

All open loop and closed loop control systems or process control stations are based on distributed digital control with built-in redundancy and interconnected via a redundant high speed bus system(s).

A redundancy provides for the process and/or instrumentation is considered in DCS to further improve overall system availability.

The single failure criteria are applied. This means that a single failure in any part of the DCS is not lead to a trip of a plant main component, e.g. GT or ST or Generator, etc. or the plant itself.

Closed loop and open loop controls, as well as protective interlocks of all Power Plant equipment is implemented in the Distributed Control System (DCS) and in the specific packaged plant control system.

Exhaust stack emissions are monitored through EPA/CARB certified continuous emissions monitoring system (CEMS). Emissions monitored include: Sulfur dioxide (SO2), Oxides of Nitrogen (NOx), Oxygen (O2), Carbon Monoxide (CO), Carbon dioxide (CO2), opacity and Particulates.

3.14.2 Plant Control Concept

The plant control concept is based on the following:

- Overall Distributed Control System DCS for the whole power producing process including its sub-systems.

- Microprocessor based DCS.

- Maximum safety for personnel and equipment.

- Safe, reliable, and efficient operation under all conditions.

- Very high availability.

- Highest degree of automation, including total plant start-up, shutdown.

- Providing all data required for operation, maintenance, and performance optimization.

- Hierarchical structure of the controls.

- Start-up and shut-down of the plant in automatic sequence (unit controller). The unit controller allows an automatic start-up/shut-down of the plant by means of sequencers. The sequencer monitor all of "permissive to start parameters" to allow the plant start-up. These "ready for start-up conditions" include appropriate feedbacks yielded with some manual operations executed locally and with equipment in service to permit its automatic start-up. Some mode selections made on VDU screens prior to plant start-up (i.e. automatic or parallel with electric grid, cold or warm start-up, etc.) to activate the type of start-up sequence (manual, semi-auto with operator consents to proceed or


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fully automatically).

- Functional groups i.e. sequence control for Steam turbine, Boiler, Water/Steam-Cycle, Balance of Plant and Electrical Equipment, etc.

- Functional sub-groups for sub-systems (i.e. redundant systems).

- Functional drive control with standardized function blocks.

- Plant coordination level (droop/isochronous mode, load rejection recover, island mode, etc.).

- Process control level (level control, temperature control, pressure control, etc.).

- Single control valve 1drive level (position control, speed control, etc.).

- Quality of design extensively proven.

9HX237380-003-001_GED 20MW Process description REV B.pdf

Documents

description of process

plant control system

water supply system

steam systems description

feedwater system

service water system

potable water system

water sampling system