A project report on adani power ltd.

1

A

Practical Training Report

On

ADANI POWER LIMITED

Submitted in partial fulfillment for the award of the degree of

BACHELOR OF TECHNOLOGY

In

Mechanical Engineering

(13 May 2013- 13 June 2013)

Submitted by :-

Nipranch Shah

10ME001073

B.Tech VIIth sem

SIR PADAMPAT SINGHANIA UNIVERSITY

UDAIPUR(RAJ.)

2

TO WHOM IT MAY CONCERN

I hereby certify that NIPRANCH SHAH roll no. 10ME001073 of Sir

Padampat Singhania University undergone thirty days industrial

training from 13th May 2013 to 13th June 2013 at our organization to

fulfill the requirement for the award of degree of B.TECH Mechanical

Engineering. During his tenure with us we found him sincere and hard

working.

We wish him a great success in the future.

Signature of student

Nipranch Shah

3

PREFACE

A student gets theoretical knowledge from classroom and gets practical

knowledge from industrial training. When these two aspects of theoretical

knowledge and practical experience together then a student is full equipped to

secure his best.

In conducting the project study in an industry, students get exposed and

have knowledge of real situation in the work field and gains experience from

them. The object of the summer training cum project is to provide an opportunity

to experience the practical aspect of Technology in any organization. It provides

a chance to get the feel of the organization and its function.

The fact that thermal energy is the major source of power generation

itself shows the importance of thermal power generation in India – more than 60

percent of electric power is produced by steam plant in India.

In steam power plants, the heat of combustion of fossil fuels is utilized

by the boilers to raise steam at high pressure and temperature. The steam so

produced is used in driving the steam turbine coupled to generators and thus in

generating ELECTRICAL ENERGY

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INTRODUCTION TO THE COMPANY

ABOUT THE COMPANY

Adani Power Limited is the power business arm of Indian business conglomerate

Adani Group with head office at Ahmedabad, Gujarat. The company is India's

largest thermal private power producer with capacity of 5280 MW and also it is

the largest solar power producer of India with capacity 40MW.

The company currently operates five supercritical boilers of 660MW each (as per

March 2012) at Mundra Gujrat & One 660MW out of 05 units at Tirora,

Maharashtra. It also operates a mega solar plant of 40MW at Surendra nagar,

Gujrat. It is India's first company to achieve the supercritical technology. The

plant is the only thermal power plant in india to be certified by UN under CDM.

The company is currently implementing 16500 MW at different stages of

construction. Its mission is to achieve 20000 MW by 2020. The company

currently produces electricity using only coal. 100MW of solar power station is

also under advanced stage of implementation at Surendranagar in Gujarat out of

which 40MW is already commissioned. The company has gone to long term

PPAs of about 7200MW of its 9280MW with government of Gujarat,

Maharashtra, Haryana and Rajasthan

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HISTORY

The company was changed to Adani Power Private Limited. The RoC issued a

fresh certificate of incorporation on 3 June 2002. The Company was, thereafter,

converted into a public limited company on 12 April 2007 and the name of the

Company was changed to Adani Power Limited. Further, upon ceasing to be a

private limited company, the word private was deleted through a special

resolution at the EGM of the Company held on 28 March 2007. The fresh

certificate of incorporation consequent to change of the name was granted by the

RoC to the Company on 12 April 2007.

Adani power was started as a power trading company 1996. It started generation

in July 2009 by implementation of its first 330MW of 4620mw at Mundra. The

Mundra super mega project is the largest coal based power project of India and

fifth largest in the world. The company commissioned another three 330 MW by

November 2010 and country's 1st supercritical unit of 660 MW on 22 December

2010, making its capacity 1980 MW. 0n 6 June 2011 it synchronized its second

unit of 660 MW bringing the total generating capacity to 2640 MW and on 2

October 2011, it synchronized its third super critical unit with national grid .With

this,Adani power has become largest thermal power generating company in the

private sector and the Mundra plant has become India's Largest Power plant with

capacity 3300MW. In February 2012, it commissioned the last unit of Mundra

Project to take its capacity to 4620MW which makes the Mundra TPP to be the

largest privately held Thermal power plant of World and fifth largest on an overall

basis(As per March,2012).

OPERATIONS

The company currently operates 4620 MW coal based Mundra Thermal Power

Station at Mundra, Gujarat. It operates first power transmission project of 400KV

Double Circuit Transmission System from the Mundra plant to Dehgam (430

km). The company operates India's first supercritical unit of 660MW. It also

implemented country's only private 1000 km HVDC transmission line for

efficient transmission of power to Haryana. The company produces 40MW of

solar power in Gujrat showing its interest in renewable energy.

The company is currently implementing thermal projects of 3300MW

(5X660MW) at Tiroda, Maharastra at Tirora one unit of 660 MW have been

generating Power since Mid of 2012 & another is going to commissioned in the

end of 2012 and 1320MW (2X660MW) at Kawai, Rajsthan, and a 100 MW solar

project at Surendranagar,Gujrat(40MW commissioned).

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FUTURE PROJECTS

As of January 2011, the company has 16500MW under implementation and

planning stage. A few of them are 3300MW coal based TPP at Bhadreswar in

Gujarat, 2640 MW TPP at Dahej in Gujarat, 1320 MW TPP at Chhindwara in

Madhya Pradesh, 2000 MW TPP at Anugul in Orissa and 2000MW gas based

power project at Mundra in Gujarat. The company is also bidding for 1000 MW

of lignite coal based power plant at Kosovo showing its international projects.

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1. INTRODUCTION TO THE POWER PLANT

Electricity is the only form of energy which is easy to produce, easy to transport,

easy to use and easy to control. So, it is mostly the terminal of energy for

transmission and distribution. Electricity consumption per capita is the index of

the living standard of people of place or country.

Electricity Demand and Supply in India: India is facing energy shortages of 11%

of demand and even higher peak shortages of 14%Demand-supply gap is more

acute in Western region (where 70% of the Project’s power will be supplied) with

energy deficit at 16% and peak deficit at 21% Capacity additions of 160,000

MW required in the next 10 years to meet India’s power demand. New capacity

need to be added using a combination of coal, hydro, gas, nuclear and wind

projects

Types of Power Plants: Electricity in bulk quantities is produced in power plants,

which can be of the following types:

Thermal

Nuclear

Hydraulic

Gas turbine

Geothermal

India’s Installed Capacity (132,329 MW)

55%

10%

26%

3%6%

Coal & lignite Gas Hydro Nuclear Other

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2. LOCATIONAL DETAILS OF MUDRA

Site Location

Latitude : 22º48’35”N

Longitude : 69º32’53”E

Nearest Village : Tunda, Taluka Mundra, Dist Kutch, Gujarat State.

Mean Sea Level : 5.1 m

Total area : 294 Ha

Highway Connectivity

State Highway : SH6 - 3.4 KM

National Highway : NH 8A extension - 5.7 km

Nearest port : Mundra Port – 17.23 km

Airport

Bhuj : 52 KM

Kandla : 64 KM

Adani Pvt. Port : 25 KM

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3.OVERVIEW OF POWER PROJECT at MUNDRA

Mundra Thermal Power Project

Power Generation Capacity

Adani Group’s foray into power sector –

The Group’s foray into power sector is natural extension for Adani Group, which

has emerged as India’s largest coal importer and second largest power entity in

the country.

Adani Power Ltd (APL) is setting up a 4620 MW power project at Mundra based

on imported coal. The execution will be done in the following stages;

2*330 Phase I (sub critical)

2*330 Phase II (sub critical)

3*660 Phase III (super critical)

2*660 Phase IV (super critical)

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4.A VIEW OF ADANI POWER LTD.

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5.DIAGRAM OF A TYPICAL COAL-FIRED THERMAL

POWER STATION

1. Cooling tower 10. Steam Control valve 19. Superheater

2. Cooling water pump 11. High pressure steam turbine 20. Forced draught (draft) fan

3. transmission line (3-phase) 12. Deaerator 21. Reheater

4. Step-up transformer (3-phase) 13. Feed water heater 22. Combustion air intake

5. Electrical generator (3-phase) 14. Coal conveyor 23. Economiser

6. Low pressure steam turbine 15. Coal hopper 24. Air preheater

7. Condensate pump 16. Coal pulveriser 25. Precipitator

8. Surface condenser 17. Boiler steam drum 26. Induced draught (draft) fan

9. Intermediate pressure steam turbine 18. Bottom ash hopper 27. Flue gas stack

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COMPONENTS

Main parts of the plant are

1. Coal conveyor………………………………………………………….13

2. Stoker……………………………………………………………….…..13

3. Pulveriser…………………………………………………………….....13

4. Boiler…………………………………………………………………...16

5. Air preheater…………………………………………………………….32

6. Deaerator……………………………………………………………….34

7. Turbine…………………………………………………………………35

8. Condenser……………………………………………………………….41

9. Cooling towers…………………………………………………………..43

10. Electrostatic precipitator…………………………………………..…...45

11. Smoke stack……………………………………………………………45

12. Generator………………………………………………………………46

13. Transformers…………………………………………………………...49

Conclusion…………………………………………………………………50

Reference…………………………………………………………………..51

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1. COAL CONVEYOR-

Coal conveyor is a belt type of arrangement. With this coal is transported from

coal storage place in power plant to the place near by boiler. Adani Power Ltd.

have the longest conveyor in India of 7KM long which convey the coal from the

port to the plant.

Phase I & Phase II

Capacity : 5.50 T/ Hr / 6.6 T/Hr

Phase III & Phase IV

Capacity : 10-104 t/h

2. STOKER-

The coal which is brought near by boiler has to put in boiler furnace for

combustion. This stoker is a mechanical device for feeding coal to a furnace. It

is also called feeder or hopper.

3. PULVERIZER OR COAL MILL-

The coal is put in the boiler after pulverization. For this pulverizer is used. A

pulverizer is a device for grinding coal for combustion in a furnace in a power

plant.

Phase I & II : 5/6 mills per unit

Phase III & IV : 6 mills per unit

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COAL MILL Phase I / Phase II

No. of coal mills : 5 Nos. / 6 Nos.

Maximum capacity : 38.7 TPH / 43.7 TPH

Mill speed : 26.4 rpm

No. of coal Bunkers : 5 Nos. / 6 Nos

Mill type : Medium speed vertical grinder roller

Make : Beijing Power Equipment Group

Coal fineness : 75 µ

Capacity of Bunkers : 400 MT Each

Capacity of coal feeder : 50 TPH

Outlet PA / Coal temp. : 85° C

Coal Mill Phase III & IV

No of Coal Mills : 6 nos.

Mill Type : Medium Speed Bowl Mill

Maximum Capacity : 86 t/h

Mill Motor Rated Power : 950KW

Gear Box : Spiral Bevel Gear & Planetary

Mill Speed : 27.7 r/min

No. of Coal Burners : 24

Type of Construction : Tangential type tilting burner

Coal Feeder Type : Variable Frequency

No. of Coal Bunkers : 6nos.

Coal Bunker Capacity : 979 m^3.

Outlet PA / Coal temp. : 85° C

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Working Of Coal Mill-

1. Anthracite coal from the coal wagons is transported to the coal handling plant.

2. Here coal is crushed in crushers and reduced to 1 inch size (approx.).

3. This crushed coal is transported to the coal bunkers with the help of coal

conveyers.

4. With the help of coal feeders coal from bunkers is made to fall in Coal mill.

5. Coal is grounded to powdery form in bowl mill. This finely grounded coal is

known as pulverized coal. Bowl mill consists of a round metallic table and three

rollers. Rotating table is made to rotate with the help of a motor. There are three

large rollers which are at a spacing of 120°.When there is no coal these rollers

does not rotate but when coal is fed to the table it packs between the table and the

roller and this forces the rollers to rotate. Coal is crushed by the crushing action

between table and rollers.

6. This pulverized coal is taken to the burner in coal pipes with the help of hot

and cold air mixture from primary air (PA) fan.

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4.BOILER-

Now that pulverized coal is put in boiler furnace. Boiler is an enclosed vessel

in which water is heated and circulated until the water is turned in to steam at

he required pressure.Coal is burned inside the combustion chamber of boiler.

The products of combustion are nothing but gases. These gases which are at

high temperature vaporize the water inside the boiler to steam. Some times

this steam is further heated in a super heater as higher the steam pressure and

temperature the greater efficiency the engine will have in converting the heat

in steam in to mechanical work. This steam at high pressure and temperature

is used directly as a heating medium, or as the working fluid in a prime mover

to convert thermal energy to mechanical work, which in turn may be converted

to electrical energy. Although other fluids are sometimes used for these

purposes, water is by far the most common because of its economy and

suitable thermodynamic characteristics.

There are two types of boiler in the power plant subcritical & supercritical

330MW unit have subcritical boiler and 660MW unit have supercritical

boilers.

Supercritical Technology

• The supercritical technology is the thermodynamic state where there is no

clear distinction between the Water and Steam phase in the Rankine Cycle

• Water reaches to steam state at a critical pressure above 22.1 MPa at 374°C.

Rankine Cycle

• The “efficiency “of the thermodynamic process is the heat energy fed into

the Rankine cycle is converted into electrical energy.

• Heat energy input to the Rankine cycle is kept constant, the output can be

increased by selecting high pressures and high temperatures.

• The key components are supercritical once through boiler and high pressure

& high temperature steam turbine.

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RANKINE CYCLE SUBCRITICAL UNIT

1 – 2 > CEP work

2 – 3 > LP heating

3 – 4 > BFP work

4 – 5 > HP heating

5 – 6 > Eco. WW

6 – 7 > superheating

7 – 8 > HPT work

8 – 9 > Reating

9 – 10 > IPT work

10 – 11 > LPT work

11 – 1 > Condensing

RANKINE CYCLE SUPERCRITICAL UNIT

1 – 2 > CEP work

2 – 2s > Regenration

2s – 3 > Boiler superheating

3 – 4 > HPT expantion

4 – 5 > Reheating

5 – 6 > IPT & LPT Expantion

6 – 1 > condenser Heat rejection

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Difference between Sub-Critical and Super-Critical Boilers

SUB-CRITICAL BOILERS SUPER-CRITICAL BOILERS

Operating pressure is below 225.5 bar. Operating pressure is above 225.5 bar.

circulation by pump assisted or natural

circulation.

Lower load start-up circulation: below

35% NR load.

Power plant efficiency is around 35% Power plant efficiency is around 39%

Pressure : 169 bar

SH Temp : 538°C

RH Temp : 538°C

Pressure : 254 bar

SH Temp : 571°C

RH Temp : 571°C

Base Additional cost to manufacturing and

erection of furnace wall.

Vertical water walls. Spiral wounded tilted water walls ensures:

Heat distribution on each wall is more

uniform than vertical water walls. Avoid

higher thermal stresses in water- walls by

reducing the fluid temperature difference

in adjacent tubes.

Steam Drum: For separation of Water and

Dry-Steam.

Steam Drum is not used.

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Boiler Design

Boiler Components

Water Walls

Separator

Economiser

Superheater

Reheater

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A DETAILED VIEW OF SUPERCRITICAL BOILER

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Water Walls /Evaporator –

The furnace circuitry consists of a lower section with optimized, vertical rifled

tubes that extend up to transition headers located at an elevation below the furnace

nose. The transition headers are interconnected to provide pressure equalization

to minimize flow unbalances and provide circuit flow stability. Above the

transition header location, vertical smooth bore tubes extend up to the furnace

roof, and also form the furnace exit screen and part of the vestibule side walls.

The tube panels that form the furnace enclosure are of Monowall type

construction. Risers pipes extend from the furnace enclosure upper headers and

are routed to a collection manifold from which the flow is directed to a final

evaporator zone that forms the furnace nose, vestibule floor and approximately

half of the vestibule sidewalls. The furnace enclosure tube size and spacing were

selected to provide a low mass flux (nominally 1000 kg/m2-s at full load) to

provide a “natural circulation” flow characteristic (as will be described in a

subsequent section) to accommodate radial heat absorption variations around the

perimeter of the furnace. Tube sizes and spacing, membrane fin sizes, and

materials are all selected to provide for base load service as well as the defined

cyclic operation of the plant.

The final evaporator zone that forms the furnace nose, vestibule floor, and part of

the vestibule sidewalls is provided to act as a buffer circuit to minimize tube

temperature differentials between the furnace evaporator walls and the adjacent

HRA enclosure superheater panels during start-up and transient conditions. The

interface between evaporator and superheater tubes is positioned near the center

of the vestibule to avoid structural discontinuities such as enclosure corners where

stress concentrations are the greatest. From the vestibule enclosure, steam is

directed to four in-line steam/water separators connected in parallel, which are

part of the start-up system, which is described below.

Separator-

Subcritical boilers are consist of drum arrangement and supercritical

boilers are consist of separator. The separator are once through

arrangement.

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DRUM vs ONCE THROUGH

Pressure Sub critical Sub & super critical

Steam separation Drum Separator(low loads)

Types Natural / assisted Sulzer / benson

Burner panel Straight tube Spiral tube / straight(MHI)

Load change Base Faster

Cold start 4-5 Hours 2 Hours

Hot start 1-2 Hours 0.5 Hours

Economiser

An economizer is a heat exchanger which raises the temperature of the

feedwater leaving the highest pressure feed water heater to about the saturation

temperature corresponding to the boiler pressure. This is done by the hot flue

gases exiting the last superheater or reheater at a temperature varying from

370`C to 540`C. The throwing away of such high temperature gases involved a

great deal of energy loss. By utilizing these gases in heating feedwater, higher

efficiency and better economy were achieved.

SH

STEAM TO

TURBINE

HEAT

DOWN

COMER

DRUM

ECO

Water Wall

ORIFICE

CIRC. PUMP

SH

STEAM TO

TURBINE

ECO

HEAT

Water Wall

23

The flue gases coming out of

the boiler carry lot of heat. An

economiser extracts a part of

this heat from the flue gases and

uses it for heating the feed water

before it enters into the steam

drum. The use of economiser

results in saving fuel

consumption and higher boiler

efficiency but needs extra

investment. In an economizer, a

large number of small diameter

thin walled tubes are placed

between two headers. Feed water enters the tubes through the other. The flue

gases flow outside the tubes.

Superheater

The superheater is a heat exchanger in which heat is transferred to the saturated

steam to increase its temperature. It raises the overall cycle efficiency. In addition

it reduces the moisture content in the last stages of the turbine and thus increases

the turbine internal efficiency. In modern utility high pressure boilers, more than

40% of the total heat absorbed in the generation of steam takes place in the

superheaters. So, large surface area is required to be provided for superheating of

steam.

Superheaters are commonly classified as:

Ceiling Superheater:

Primary Superheater or the Low Temperature Superheater (LTSH):

Convection Superheater:

Platen or pendent panel Superheater:

Ceiling Superheater: A panel of small bore tubes interconnecting long header

at both ends, forms the roof of the furnace and the second pass of flue gas path.

From here the steam flows through different stages of superheating.

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Primary Superheater or the Low Temperature Superheater

(LTSH): A panel of small bore tubes formed in “U” shaped coils is connected

to long headers on either ends and located horizontally in second Pass of the flue

gas path above the economizer. Superheated steam from Ceiling Superheater

enters at inlet and gets heated further, raising the steam temperature. It is located

in the low temperature region of flue gas path. The steam just gets superheated

and the temperature range to which the steam is heated is very low compared to

the final outlet steam temperature and hence called Low Temperature

Superheater.

Platen or pendent panel Superheater: Steam from Primary Superheater

enters the Platen Superheater. The Platen Superheater is located just above the

combustion zone at the top of the furnace. Mainly it receives radiant heat from

the furnace and the steam is further superheated. They are hanging panels

arranged in rows across the width of the furnace. Each panel is connected with its

own small inlet and outlet headers, which are in turn is connected to the big and

long common headers, on both inlet and outlet sides.

Convection Superheater: From Platen Superheater the steam enters the next

stage of superheating, which is called Convection Superheater. Convection

Superheater is located away from radiant zone of the furnace and the heat transfer

takes place by convection process, when the mass of flue gases pass through and

across the convection Superheater coils. The steam gets its final heat addition

while flowing through the final Superheater stage and flows out through main

steam pipes, for the end use.

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Reheater :

Some of the heat of superheated steam is used to rotate the turbine where it loses

some of its energy. Reheater is also steam boiler component in which heat is

added to this intermediate-pressure steam, which has given up some of its energy

in expansion through the high-pressure turbine. The steam after reheating is used

to rotate the second steam turbine where the heat is converted to mechanical

energy. This mechanical energy is used to run the alternator, which is coupled to

turbine , there by generating electrical energy.

Boiler Technical data:-

I. Manufacturer : Harbine boiler company

II. Model : HG 2115/25.4-HM15

III. Type : Supercritical once through, primary

inter-mediate reheating, single furnace,

II type suspended structure.

IV. Type of firing : Wall mounted tangential firing

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V. Water volume capacity : Economizer system – 65 m3 Water wall system – 70 m3

Start up system – 22 m3

Super heater – 227 m3

Re-heater – 435 m3

DESIGN SPECIFICATION OF THE BOILER

No. Item Specification Unit

1 Model HG2115/25.4 – HM15

2 Mode Once-through boiler with

supercritical pressure

3 Superheater steam flow 2115.5 t/h

4 Superheater outlet pressure 25.4 Mpa

5 Superheater outlet temperature 571 °C

6 Reheated steam flow 1714.9 t/h

7 Reheater inlet pressure 4.794 Mpa

8 Reheater outlet pressure 4.604 Mpa

9 Reheater inlet temperature 328.6 °C

10 Reheater outlet temperature 569 °C

11 Feedwater pressure 28.87 Mpa(g)

12 Feedwater temperature 292.6 °C

13 Separator’s steam temperature 421 °C

14 Air preheater’s outlet air temperature 153.3 °C

15 Uncorrected after 147.2 °C

16 Calculating thermal efficiency of boiler 92.62% (BMCR)

17 Guarantee thermal efficiency of boiler 92.17% (TRL)

18 Pulverizing type Cold primary fan positive pressure

direct blowing system

19 Burner type Wall – mounted tangential circle

combustion, dry ash extraction

20 Draft type Balanced ventilation

21 Design fuel Indonesian coal

22 Check fuel Indonesian coal

23 Coal-fired quantity of the boiler 338 t/h

24 Check fuel 300 t/h

25 Fuel oil startup and ignition LDO and HDO

26 Superheated steam temperature adjustment Ratio of coal and water, secondary

spray desuperheating

27

Furnace detail

Furnace dimension (width×height×height×depth)= 23567×17012×616 mm43

Horizontal pass depth : 5322 mm

Back pass front duct depth : 8618 mm

Break pass back duct depth : 9098 mm

Water wall lower header elevation : 7000 mm

28

29

DRAUGHT SYSTEM

Large amount of air is required for combustion of fuel. The gaseous combustion

products in huge quantity have also to be removed continuously from the furnace.

To produce the required flow of air or combustion gas, a pressure differential is

needed. The term “draught” or “draft” is used to define the static pressure in the

furnace, in the various ducts, and the stack.

The function of the draught system is basically two folds:

To supply to the furnace the required quantity of air for complete of fuel.

To remove the gaseous products of combustion from the furnace and throw

these through chimney or stack to the atmosphere.

There are two ways of producing draught:

Natural draught

Mechanical draught

Natural Draught: The natural draught is produced by a chimney or a stack. It is

caused by the density difference between the atmospheric air and the hot gas in

the stack.

Mechanical Draught: Mechanical draught is produced by fans.

Induced and Forced Draught Fans:

Big fans may be used for sucking and throwing out the flue gas through the

chimney, thereby creating adequate draught inside the furnace. Such Fans are

termed as Induced Draught Fans. Forced draught Fans may also be deployed for

supply of required quantity of combustion air and maintaining a positive draught

inside the furnace. The flue gas will be pushed out the stack with the draught

pressure available in the furnace.

Forced Draught Fan:

Air drawn from atmosphere is forced into the furnace, at a pressure higher than

the outside atmosphere, by big centrifugal fan or fans to create turbulence and to

provide adequate Oxygen for combustion. Hence the system is known by the

name Forced draught system and the fan, used to push through combustion air

under pressure, is called Forced Draught Fan. F D fan is normally located at the

front or sideways of the furnace.

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Induced Draught Fan

Instead of drawing atmospheric air and pushing through furnace, a centrifugal fan

can be deployed to draw out the air from the furnace and throw out through the

chimney, thereby creating negative pressure in the combustion zone and maintain

the negative draught through out the furnace. The system is called Induced

Draught system and the fan deployed for this purpose is known as Induced

Draught Fan.

In the Induced Draught system, the fan is fitted at back end of the furnace or near

the base of the chimney. Due to the negative pressure created inside the furnace,

by the action of the fan, flue gas will not come out of combustion space i.e.

Furnace. The entry of air to Boiler is regulated through air registers and dampers.

31

For similar capacity boilers, the size of an induced draught fan will be more than

the size of the forced draught fan required for a forced draught system. This is

because the products of combustion is always much higher in volume than the

volume of combustion air handled by the forced draught fan. Further the flue gas

is hotter and the density is less. Hence the volume is much more. According to

Charles Law, when a gas is heated the volume will proportionately increase at

constant pressure, with the raise in temperature. According to Boyles Law, if

pressure inside a vessel is increased, the volume will proportionately decrease

and the vice-versa is also true (P ∝ 1/V).

Primary air fan

These are the large high pressure fans which supply the air needed to dry and

transport coal either directly from the coal mills to the furnace or to the

intermediate bunker. These fans may be located before or after the milling

equipment. The most common applications are cold primary air fans, hot primary

air fans.

The coal primary air fan is located before air heater and draws air from the atm.

And supplies the energy required to force air through air heaters, ducts, mills and

fuel piping. With a cold air system like this the FD fan may be made smaller as

PA fan supply part of combustion air.

For primary air fans boosts the air pressure from air heaters for drying and

transporting coal from pulverisers in these systems the total air has to be handled

by FD fans and each mill will be provided with a primary air fan at the mill inlet

side the primary fan in these case has to handle hot air probably with some amount

of fly ash carried from the air pre-heater.

Technical data :-

Description Unit FD PA ID

Fan Model Axial Fan Axial Fan Axial Fan

Rated Power of Motor kW 2000 3150 4500

Rotational Speed of Fan r/min 990 1490 990

32

5.AIR PREHEATER:

Air preheater are in generally divided into following two types:

Recuperative

Regenerative

In Recuperative APH, heat is directly transferred from the hot gases to the air

across the heat exchanging surface. They are commonly tubular, although some

plate types are still in use. Tubular units are essentially counter-flow shell-and-

tube heat exchangers in which the hot gases flow inside the vertical straight tubes

and air flows outside. Baffles are provided to maximize air contact with the hot

tubes.

Regenerative APH are also known as storage type heat exchangers, have an

energy storage medium, called the matrix, which is alternately exposed to the hot

and cold fluids. When the hot flue gases flow through the matrix in the first half

of the cycle, the matrix is heated and the gas is cooled. In the next half of the

Volume flow of fan inlet m^3/s 230.1 112.9 538.4

Temperature of fan inlet ˚C 47.8 47.8 137

Fan total pressure Pa 3871 12671 3989

Total efficiency % 87 88 85.5

External Diameter of

Blade

mm 2880 2100 3349

Diameter of Impeller mm 1600 1400 1884

Blade No. of Each Grade Nos. 26 22 18

33

cycle when air flows through the matrix, air gets heated and the matrix is cooled.

The cycle repeats itself.

34

6.DEAERATOR :

A steam generating boiler requires that the boiler feed water should be devoid of

air and other dissolved gases, particularly corrosive ones, in order to

avoid corrosion of the metal.

Generally, power stations use a Deaerator to provide for the removal of air and

other dissolved gases from the boiler feed water. A deaerator typically includes a

vertical, domed deaeration section mounted on top of a horizontal cylindrical

vessel which serves as the deaerated boiler feed water storage tank.

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7.STEAM TURBINE

INTRODUCTION:-

Turbine is a machine in which a shaft is rotated steadily by impact

or reaction of current or stream of working substance (steam, air, water, gases

etc) upon blades of a wheel. It converts the potential or kinetic energy of the

working substance into mechanical power by virtue of dynamic action of working

substance. When the working substance is steam it is called the steam turbine.

PRINCIPAL OF OPERATION OF STEAM TURBINE:-

Working of the steam turbine depends wholly upon the dynamic action of Steam.

The steam is caused to fall in pressure in a passage of nozzle: doe to this fall in

pressure a certain amount of heat energy is converted into mechanical kinetic

energy and the steam is set moving with a greater velocity. The rapidly moving

particles of steam, enter the moving part of the turbine and here suffer a change

in direction of motion which gives rose to change of momentum and therefore to

a force. This constitutes the driving force of the machine. The processor of

expansion and direction changing may occur once or a number of times in

succession and may be carried out with difference of detail. The passage of steam

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through moving part of the commonly called the blade, may take place in such a

manner that the pressure at the outlet side of the blade is equal to that at the inlet

inside.Such a turbine is broadly termed as impulse turbine.On the other hand the

pressure of the steam at outlet from the moving blade may be less than that at the

inlet side of the blades; the drop in pressure suffered by the steam during its flow

through the moving causes a further generation of kinetic energy within the

blades and adds to the propelling force which is applied to the turbine rotor.Such

a turbine is broadly termed as impulse reaction turbine.

The majority of the steam turbine have, therefore two important

elements, or Sets of such elements.These are the nozzle in which the system

expands from high pressure end a state of comparative rest to a lower pressure

end a status of comparatively rapid motion.

The blade or deflector, in which the steam particles changes its

directions and hence its momentum changes . The blades are attach to the rotating

elements are attached to the stationary part of the turbine which is usually termed

the stator, casing or cylinder.

Although the fundamental principles on which all steam turbine

operate the same, yet the methods where by these principles carried into effect

very end as a result, certain types of turbine have come into existence.

1. Simple impulse steam turbine.

2. The pressure compounded impulse turbine.

3. Simple velocity compounded impulse turbine.

4. Pressure-velocity compounded turbine.

5. Pure reaction turbine.

6. Impulse reaction turbine.

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Description of Steam Turbines:-

HP Turbine:-

The HP casing is a barrel type casing without axial joint. Because of its rotation

symmetry the barrel type casing remain constant in shape and leak proof during

quick change in temperature. The inner casing too is cylinder in shape as

horizontal joint flange are relieved by higher pressure arising outside and this can

kept small. Due to this reason barrel type casing are especially suitable for quick

start up and loading.The HP turbine consists of 25 reaction stages. The moving

and stationary blades are inserted into appropriately shapes into inner casing and

the shaft to reduce leakage losses at blade tips.

IP Turbine:-

The IP part of turbine is of double flow construction. The casing of IP turbine is

split horizontally and is of double shell construction. The double flow inner

casing is supported kinematically in the outer casing. The steam from HP turbine

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after reheating enters the inner casing from above and below through two inlet

nozzles. The centre flows compensates the axial thrust and prevent steam inlet

temperature affecting brackets, bearing etc. The arrangements of inner casing

confines high steam inlet condition to admission branch of casing, while the joints

of outer casing is subjected only to lower pressure and temperature at the exhaust

of inner casing. The pressure in outer casing relieves the joint of inner casing so

that this joint is to be sealed only against resulting differential pressure.

The IP turbine consists of 20 reaction stages per flow. The moving and stationary

blades are inserted in appropriately shaped grooves in shaft and inner casing.

LP Turbine:-

The casing of double flow type LP turbine is of three shell design. The shells are

axially split and have rigidly welded construction. The outer casing consist of the

front and rear walls , the lateral longitudinal support bearing and upper part.

The outer casing is supported by the ends of longitudinal beams on the base plates

of foundation. The double flow inner casing consist of outer shell and inner shell.

The inner shell is attached to outer shell with provision of free thermal movement.

Steam admitted to LP turbine from IP turbine flows into the inner casing from

both sides through steam inlet nozzles.

Engineering Design Aspects

Steam and heat cycle

Type (N660.24.2/566/566)

Dongfang Steam Turbine

Impulse type, tandem compound three

cylinders, four flow exhaust, single

reheat, condensing turbine

TMCR Output 660 MW

BMCR Output 694 MW

HP turbine 8 Stages, 2 Stop valves, 4 control valves

IP turbine 6 Stages, 2 Stop valves, 2 control valves

LP turbine Double flow 2x7 Stages

HP heaters 3

LP heaters 4

No of Extractions 8

No of Journal bearings 6

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STEAM FLOW DIAGRAM OF TURBINES AND HEATERS

LOSSES IN STEAM TURBINE

• Friction losses

• Leakage losses

• Windage loss( More in Rotors having Discs)

• Exit Velocity loss

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• Incidence and Exit loss

• Secondary loss

• Loss due to wetness

• Loss at theBearings(appx 0.3% of total output)

• Off design losses

MAIN LOSSES IN TURBINE

FRICTION LOSS-

It is more in Impulse turbines than Reaction Turbines,because impulse turbines

uses high velocity of steam and further the flow in the moving blades of the

Reaction turbines is accelerating which leads to better and smooth flow(Turbulent

flow gets converted to Laminar flow)

LEAKAGES LOSS-

It is more in Reaction turbines than Impulse turbines because there is Pressure

difference across the moving stage of reaction turbines which leads to the

Leakages. In Impulse turbine such condition is not there.

• Leakage loss predominates over friction losses in the High Pressure end of

the Turbine

• Friction Losses predominates over the Leakage's Loss in the Low Pressure

end of the Turbine.

• It is observed that the Efficiency of The IP Turbine is the maximum

followed by The HP and LP Turbine.

Features of 660 MW Mundra Steam Turbine

Combined HP & IP Section

Shorter Turbine Length – More Efficient

Reduced No. of Bearings

Reduced No. of Packing segments

Opposite flow in HP & IP Turbines makes thrust force balanced

Casings upper & lower halves are nearly symmetrical

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8.Condenser :

Steam after rotating steam turbine comes to condenser. Condenser refers here

to the shell and tube heat exchanger (or surface condenser) installed at the

outlet of every steam turbine in Thermal power stations of utility companies

generally. These condensers are heat exchangers which convert steam from its

gaseous to its liquid state, also known as phase transition. In so doing, the

latent heat of steam is given out inside the condenser. Where water is in short

supply an air cooled condenser is often used. An air cooled condenser is

however significantly more expensive and cannot achieve as low a steam

turbine backpressure (and therefore less efficient) as a surface condenser.

The purpose is to condense the outlet (or exhaust) steam from steam turbine

to obtain maximum efficiency and also to get the condensed steam in the form

of pure water, otherwise known as condensate, back to steam generator or

(boiler) as boiler feed water.

heat exchanger

Tubes sea water

steam water (condensate)

vacuum is created due to steam / condensate volume difference

vacuum is maintained by constant cool water circulation through the

tubes

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9.COOLING TOWERS :

The condensate (water) formed in the condenser after condensation is initially at

high temperature. This hot water is passed to cooling towers. It is a tower- or

building-like device in which atmospheric air (the heat receiver) circulates in

direct or indirect contact with warmer water (the heat source) and the water is

thereby cooled. A cooling tower may serve as the heat sink in a conventional

thermodynamic process, such as refrigeration or steam power generation, and

when it is convenient or desirable to make final heat rejection to atmospheric

air. Water, acting as the heat-transfer fluid, gives up heat to atmospheric air, and

thus cooled, is recirculated through the system, affording economical operation

of the process.

COOLING TOWER :

Inlet water temperature : 60 °C

Outlet water temperature : 35 °C

Output : 150 m3/h

Motor Power : 7.5 kW

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10.ELECTROSTATIC PRECIPITATOR(ESP) :

It is a device which removes dust or other finely divided particles from flue gases

by charging the particles inductively with an electric field, then attracting them

to highly charged collector plates. Also known as precipitator. The process

depends on two steps. In the first step the suspension passes through an electric

discharge (corona discharge) area where ionization of the gas occurs. The ions

produced collide with the suspended particles and confer on them an electric

charge. The charged particles drift toward an electrode of opposite sign and are

deposited on the electrode where their electric charge is neutralized. The

phenomenon would be more correctly designated as electrode position from the

gas phase.

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TECHNICAL DATA

330 MW

ESP ash collection 80 % (i.e.13.6 t/hr) of total ash generated.

Total height of ESP 27 m

Insulation Glass wool

Electric insulation material Porcelain insulator

Total efficiency 99.9%

1st field 80-85 %

2nd field 10-12 %

3rd and 4th field Rest

660 MW

ESP ash collection 99.2 % of total ash generated.

First field : 1488

second field : 210

Third field : 42

fourth field : 8

Fifth field : 2

No. of electrical fields in series : 5

11.SMOKE STACK/CHIMNEY :

A chimney is a system for venting hot flue gases or smoke from

a boiler, stove, furnace or fireplace to the outside atmosphere. They are typically

almost vertical to ensure that the hot gases flow smoothly, drawing air into

the combustion through the chimney effect (also known as the stack effect). The

space inside a chimney is called a flue. Chimneys may be found in buildings,

steam locomotives and ships. In the US, the term smokestack (colloquially, stack)

is also used when referring to locomotive chimneys. The term funnel is generally

used for ship chimneys and sometimes used to refer to locomotive chimneys.

Chimneys are tall to increase their draw of air for combustion and to disperse

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pollutants in the flue gases over a greater area so as to reduce the pollutant

concentrations in compliance with regulatory or other limits.

These are 220M tall RCC structures with single / multiple flues inside the

concrete shells (one flue per 330 MW units). The height of these chimneys varies

depending on the location of power plant.

Stage I Chimney: 220M (two flue’s inside the outer concrete shell)

Stage II Chimney: 275M (two flue’s inside the outer concrete shell)

Stage III Chimney: 275M (two flue’s inside the outer concrete shell)

Stage IV Chimney: 275M (three flue’s inside the outer concrete shell)

12.GENERATOR :

An alternator is an electromechanical device that converts mechanical energy

to alternating current electrical energy. Most alternators use a rotating magnetic

field. Different geometries - such as a linear alternator for use with stirling

engines - are also occasionally used. In principle, any AC generator can be called

an alternator, but usually the word refers to small rotating machines driven by

automotive and other internal combustion engines.

Generator is connected with the all HP, IP and LP turbines so when the turbines

rotates by the pressure of the steam the generator also rotate and due to magnetic

field it generates electricity.

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In 330MW unit the generator is connected with one HP turbine ,one IP turbine

and one LP turbine but In 660MW unit the generator is connected with one HP

turbine, one IP turbine and two LP turbine.

Generator 330MW units Specifications

Active Output 330 MW

Apparent Output 388 MVA

Rated Terminal Voltage 24 KV+/- 5%

Rated Frequency 50 Hz +3% to -5%

Rated Power Factor 0.85 lagging

Phases 3

Phase Connection Star

Rated Speed 3000 rpm

Reference Standard IEC-34

Live Terminals brought out 3

Neutral Terminal brought out 3

Short Circuit ratio 0.60 min

Short time overload capability 150% for 15 sec

Class of Insulation for Stator & Rotor F

Temp. Rise of Stator/Rotor Limited to Class B

Cooling for Stator Core/Rotor Hydrogen

Over Speed 120% for 2 mins

3 Phase short circuit withstand time 3 Sec

Degree of Protection IP 54

Telephonic Harmonic interference factor Less than 1.5%

Inertia Constant of Generator 2 KW sec/ KVA

Type of Generator Earthing Earthed through

distribution Tr.

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Cooling of Stator Winding DM Water

Type of Excitation Brushless without PMG

DM Cold water Temp. 38 °C

Cold Hydrogen gas temperature 46 °C

Generator (660MW units) Specifications

Manufacturer Dongfang Electric Machinery Ltd

Model QFSN-660-2-2D

Rated Capacity 776.5 MVA

Rated Power 660 MW

Rated stator voltage 22 kV, +/- 5%

Rated stator current 20377 A

Field Current 4476 A

Phase 3

No of Terminals 6

Frequency 50 Hz

Power factor 0.85 lag

Rated speed 3000 rpm

Wiring type Y - Y type ( Double star)

Cooling method Water, hydrogen

Cooling water of stator winding Directly Water cooled,

Flow 102 m³/Hr

Cooling Water Pressure 0.20 MPa

(Stator Winding)

Cooling of stator core & rotor Directly hydrogen cooled

Insulation Class F

Excitation Terminal, Self, static excitation.

Generator rotating direction Clock wise

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Rated Hydrogen Pressure 0.45 MPa (g) Max 0.5 MPa

Excitation Type Static Thyristor excitation

Short Circuit Ratio >= 0.5

Efficiency >= 98.8%

DC Resistance of stator winding/phase 0.001196 W at 15 °C

DC Resistance of field winding 0.077723 W at 15 °C

13.TRANSFORMERS :

It is a device that transfers electric energy from one alternating-current circuit to

one or more other circuits, either increasing (stepping up) or reducing (stepping

down) the voltage. Uses for transformers include reducing the line voltage to

operate low-voltage devices and raising the voltage from electric generators so

that electric power can be transmitted over long distances. Transformers act

through electromagnetic induction; current in the primary coil induces current in

the secondary coil. The secondary voltage is calculated by multiplying the

primary voltage by the ratio of the number of turns in the secondary coil to that

in the primary.

After generating the electricity by the generator the electricity passes through

the transformers and this is how the electricity is generated.

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CONCLUSION

The first phase of practical training has proved to be quiet fruitful. It provided an

opportunity for encounter with such hardworking engineers.

The architecture of the power plant the way various units are linked

and the way working of whole plant is controlled make the student realize that

engineering is not just learning the structured description and working of various

machines, but the greater part is of planning proper management.

It also provides an opportunities to learn low technology used at

proper place and time can cave a lot of labour But there are few factors that

require special attention. Training is not carried out into its tree sprit. It is

recommended that there should be some project specially meant for students

where presence of authorities should be ensured. There should be strict

monitoring of the performance of students and system of grading be improved on

the basis of work done.

However training has proved to be quite fruitful. It has allowed an

opportunity to get an exposure of the practical implementation to theoretical

fundamentals.

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REFERENCES

www.adani.com

en.wikipedia.org

economictimes.indiatimes.com

energy.siemens.com

www.mapsofindia.com

www.ntpc.co.in

timesofindia.indiatimes.com

adani technical diary

adani training manual