Thermal Report Ankit

7/30/2019 Thermal Report Ankit

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A

REPORT

ON

Practical Summer Training Undergone At

KOTA SUPER THERMAL POWER STATION, KOTA

2012-2013

Submitted By: - Submitted To:-

Ankit Vijay Mr. S.C.Mittal

College roll no: - 09/006

Batch: - EE-1

Department of Electrical Engineering

University College of Engineering

Rajasthan Technical University, Kota


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PREFACE

Practical knowledge means the visualization of the knowledge, which we read in

books. For this we perform experiments and get observations. Practical knowledge is

very important in every field. One must be familiar with the problems related to that

field so that he may solve them and became successful person.

After achieving the proper goal of life an Engineer has to enter in professional life.

According to this life he has to serve an industry, may be public or private sector or

self-own. For the efficient work in the field he must be well aware of practical

knowledge as well as theoretical knowledge.

To be a good Engineer, one must be aware of the industrial environment & must

know about management, working in industry,labour problems etc., so he can tackle

them successfully.

Due to all the above reasons & to bridge the gap between theory and practical, our

engineering curriculum provides a practical training course of 30 days. During this

period a student in industry and gets all type of experience and knowledge about the

working and maintenance of various types of machinery.

This report presents a simple, implicit and yet a legrous and comprehensive

treatment of equipment of thermal power plant & their capability & maintenance

scheme. This report consist of overall view of Kota Super Thermal Power Station &

its different parts like steam overview, turbine, generator, boiler, transformer,

switchgear, coal handling plant, ash handling plant, its common auxiliaries, control

room and water chemistry of plant.


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ACKNOWLEDGMENT

It is a matter of great pleasure and privilege for me to present this report on 30 days

training at KOTA SUPER THERMAL POWER STATION.

I am grateful to Mr.K.C.Madan, training officer, K.S.T.P.S., Mr. Rajesh Raipuria,

A.En., K.S.T.P.S., for his kind co-operation. I am thankful to all those engineers and

operators without which it was not possible for me to clear my doubts and

difficulties.

I am also thankful of technical staff of the department; I took training in, for they

were always there to solve problems.

Ankit Vijay

4TH

YEAR, 7TH

SEM.


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INDEX

CONTENTS PAGE NO.

1) Preface i

2) Acknowledgment ii

3) INTRODUCTION 5-8

4) GENERAL LAYOUT AND BASIC IDEA 9-11

5) PROCESSING OVERVIEW 12-17

6) BOILER 18-27

7) STEAM TURBINE & GENERATION 28-31

8) WATER TREATMENT PLANT 32-34

9) SWITCH YARD 35-36

10) PROTECTION AND MISCELLANEOUS 37-40

11) CONCLUSION 41

12)SCHEDULE OF THE INDUSTRIAL TRAINING 42


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CHAPTER -1

INTRODUCTION

1.GENERAL OVERVIEWFor the power generation with 2x110 MW, 3x210 MW, 2x195MW, K.S.T.P.S.

authorities are required to have full control over all the auxiliaries which are

basically operated on L.T. System i.e. 415 V 3- power supply is made

available to the system after providing the station transformer of 3x50 MVA

capacity with different service transformers of capacity 1.0 MVA, 1.5 MVA,

2.0 MVA, which are located near the load centre as the transformer having the

voltage of 6.6 KV /415 V. The 6.6 KV power is distributed through 6.6 KV

interconnected Bus System for all the SEVEN units with a control through DC

of 220 V.The 415 V power supply is done through a L.T. SWGR (Switchgear)

which are located nearby the distribution transformer as well as the load

centers. The 6.6 KV power supply which are either MOCB (Minimum Oil

Circuit Breaker) or Air Circuit Breakers.

The 6.6 KV power is supplied to various draining equipments is made

through breakers which are either MOCB or air circuit breaker which areeither of voltage makers as well as SF 6 of NGEF make. The LT supply is

also controlled through air break circuit breakers. The various H.T. motors are

switched on through Direct ON line (DOL) in order to increase the availability

of equipment at full efficiency without time gap.

Further, the 6.6 KV system which is normally in delta configuration and

termed as an unearthed system. Earthing is detected by a protection system


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with alarm facility to take remedial measures immediately and at the same

time to maintain the generation level in the same condition, prior to occurring

the earth fault the single phase earth fault is detected in due course till the

motor is not earthed to any phase. PUBLIC ADDRESS SYSTEM is

available through in area of each unit which helps in fast communication for

prompt remedial measure.

Soot Blowers are there in the boiler area on the furnace side or Zone

which helps in blowing the soot / ash deposition regularly of the furnace wall /

economizer tubes to keep heat transfer at the required parameter.

In April 1973, Central Electricity Authority prepared a Project Report

for power station comprising of the two units of each of capacity 110 MW for

RSEB. Subsequently in September 1975 this was revised by the Consultant

Thermal Design Organization, Central Electricity Authority for invention of

2x110 MW units being manufactured by BHEL, Hyderabad in 1st Stage. The

planning commission cleared the project report in Sept, 1976 for installation of

two units each of 110 MW in first estimated cost of Rs. 143 Crores.*The total power generated in KSTPS is 1240 MW.

1.1 Designed Stages

STAGE I - 2x110 MW STAGE II - 2X210 MW STAGE III - 1X210 MW STAGE IV - 1X195 MW STAGE V - 1X195 MW


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1.2 Location

The Kota Thermal Power Station is ideally on the left bank of Chambal River

at Up Stream of Kota Barrage. The large expanse of water reached by the

barrage provides an efficient direct circulation of cooling system for the power

station. The 220 KV GSS is within Kms. from the power station.

1.3 Land

Land measuring approx. 250 hectares was required for the project in 1976. Ash

tank is constructed very near to the plant for the ease of disposal of ash and

slurry.

1.4 Coal

Coal India limited owns and operates all the major coal fields in India through

its coal producing subsidiary companies viz. Eastern Coal Fields Limited,

Western Coal Fields Limited. Coal India limited supplies coal from its coal

mines of coal producing subsidiaries BCCL, SECL & ECL to Kota Thermal

Power Station through railway wagons. The average distances of SECL, ECL

& BCCL are 800, 950 and 1350 Kms. respectively.

1.5 Water

The source of water for power station is reservoir formed by Kota Barrage on

the Chambal River. In case of large capacity plants huge quantities of coal and

water is required. The cost of transporting coal and water is particularly high.

Therefore, as far as possible, the plant must be located near the pit rather than


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at load centre for load above 200 MW and 375 MW. The transportation of

electrical energy is more economical as compared to the transportation of coal.

1.6 Design Features

The satisfactory design consists of the following steps.

Estimation of cost. Selection of site. Capacity of Power Station. Selection of Boiler & Turbine. Selection of Condensing Unit. Selection of Electrical Generator. Selection of Cooling System. Design of Control and instrumentation system.

The design of steam power station requires wide experience as the subsequent

operation and maintenance are greatly affected by its design. The most

efficient design consists of properly sized component designed to operate

safely and conveniently along with its auxiliaries and installation.


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CHAPTER -2

GENERAL LAYOUT AND BASIC IDEA

A control system of station basically works on Rankin Cycle. Steam is

produced in Boiler is exported in prime mover and is condensed in condenser

to be fed into the boiler again.

Figure 2.1


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The Kota Thermal Power Station is divided in four main circuits:

Fuel and Ash Circuit. Air and Gas Circuit. Feed water and Steam Circuit. Cooling Water Circuit.

1. FUEL & ASH CIRCUITFuel from the storage is fed to the boiler through fuel handling device. The

fuel used in KSTPS is coal, which on combustion in the boiler produces the

ash. The quantity of ash produced is approximately 35-40% of coal used. This

ash is collected at the back of the boiler and removed to ash storage tank

through ash disposal equipment.

2. AIR AND GAS CIRCUITAir from the atmosphere is supplied to the combustion chamber of Boiler

through the action of forced draft fan and induced draft fan. The flue gases

first pass around the boiler tubes and superheated tubes in the furnace, next

through dust collector (ESP) & then economizer. Finally, they are exhausted

to the atmosphere through fans.

3. FEED WATER AND STEAM CIRCUITThe condensate leaving the condenser is first heated in LP heaters through

extracted steam from the lower pressure extraction of the turbine. Then it goes

to de-aerator where extra air and non-condensable gases are removed from the

hot water to avoid pitting/oxidation. From de-aerator it goes to BFP (boiler

feed pump) which increases the pressure of the water, then passes through the


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HP heater and enters into the boiler drum through economizer. This wet steam

passes through superheater. From superheater it goes into the HP turbine then

to IP turbine and finally to the LP turbine and then exhausted through the

condenser into hot well.

4. COOLING WATER CIRCUITA large quantity of cooling water is required to condense the steam in

condenser and marinating low pressure in it. The water is drawn from reservoir

and after use it is drained back into the river.


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CHAPTER -3

PROCESSING OVERVIEW

1.COAL HANDLING PLANTIt can be called the heart of thermal power plant because it provides the fuel

for combustion in boiler. The coal is brought to the KSTPS through rails via

16 railway tracks. The main coal sources for KSTPS are SECL (South Eastern

Coalfields Limited), ECL (Eastern Coalfield Limited) and BCCL (Bharat

Coking Coal Limited). Everyday 6 to 7 trains of coal are unloaded at KSTPS.Each train consists of 58 wagons and each wagon consists of 60 tonnes of coal.

The approximate consumption at KSTPS is about 20,000 tonnes per day. It

costs approximate 2 crores of rupees per day including transportation

expenses.

The coal is firstly unloaded from wagon by wagon tipplers, then crushed

by crushers and magnetic pulley and pulverized to be transformed to the

boiler. The whole transportation of coal is through conveyor belt operated by

3- Induction motor.

The coal handling plant can broadly be divided into three sections:

1) Wagon Unloading System

2) Crushing System

3) Conveying System

1.1WAGON UNLOADING SYSTEM

Wagon Tippler unloads the coal from wagon to hopper which is made of Iron,

in the form of net so that coal pieces of only equal to and less than 200 mm


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size pass through it. The bigger ones are broken by the workers with the help

of hammers. From the hopper coal pieces fall on the vibrator. It is a

mechanical system having two rollers each at its ends. The rollers roll with the

help of a rope moving on pulley operated by a slip ring induction motor.

Figure 3.1

The four rollers place themselves respectively behind the first and the last

pair of wheels of the wagon. When the motor operates the rollers roll in

forward direction moving the wagon towards the Wagon Table. On the

Wagon table a limit is specified in which wagon has to be kept otherwise the

triple would not be achieved.


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1.2 CRUSHING SYSTEM

It consists of crushers which are used to crush the coal to 20 mm size. There

are mainly two types of crushers working in KSTPS:-

Primary Crushers i.e. 1) Rail crushers or 2) Rotary breaker.

Secondary Crushers i.e. Ring granulators.

1.2.1 Primary Crushers:- These are provided in only CHP stage 3. These are:

1) Rail crushers, 2) Rotary breaker

1.2.2 Secondary Crusher:- In this, there are following ways to reduce

material size:

1) Impact attrition, 2) Shearing, 3) Compression.

Most of the crushers employ a combination of three crushing methods.

1.3 CONVEYING SYSTEM

The stacker/re-claimer unit stacks the material on to the pipe and feeds on to

the main line conveyor. Simultaneously vibrating feeder on the intermediate

conveyor feeds the boom conveyor of the stacker/reclaimer. Feeder is erectedto serve the purpose of storage. Underground machines known as plow feeder

collect the coal from conveyor and drop it to other side from other conveyor,

with the help of jaws and this coal is taken to huge erected structure from

where the coal falls to the ground.


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Figure 3.22.ASH HANDLING PLANT

This plant can be divided into 3 sub plants as follows:-

1) Fuel and Ash Plant

2) Air and Gas Plant

3) Ash Disposal & Dust Collection Plant

2.1 FUEL AND ASH PLANT

Coal is used as combustion material in KSTPS. The Pulverization also

increases the overall efficiency and flexibility of boilers. However, for light

up and withstand static load, oil burners are also used. Ash produced as the

result of combustion of coal is connected and removed by ash handling plant

which consists of specially designed bottom ash and fly ash in electro static

precipitator economizer.

2.2 AIR & GAS PLANT

Air from atmosphere is supplied to combustion chamber of boiler through the

action of forced draft fan. In KTPS there are 2 FD fans and 3 ID fans available


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for draft system per unit. Additional amount of air used called secondary air is

supplied by Forced Draft (FD) Fan. The air, before being supplied to the

boiler, passes through pre-heater where the flue gases formed due to

combustion of coal heat it. In economizer the heat of flue gases raises the

temperature of feed water. Finally the flue gases after passing through the

Electro-Static Precipitator is exhausted through chimney.

2.3 ASH DISPOSAL & DUST COLLECTION PLANT

KSTPS has dry bottom furnace. Bottom ash hopper receives the bottom ash

from the furnace from where it is stored and discharged through the clinkergrinder. Two slurry pumps are provided which are common to both units &

used to make slurry and further transportation to ash dyke through pipe line.

Dry free fly ash is collected in 31 fly ash hoppers, handled by two independent

fly ash system. The ash removed from fly ash hoppers is in dry state & carried

to the collecting equipment where it is mixed with water and resulting slurry

sump is discharged.

3. ELECTRO-STATIC PRECIPITATOR

3.1 SCOPE & PRINCIPLE OF OPERATION

As far as air pollution is concerned, various flue gases filter are available. The

choice depends on the size of suspended particle matter. These filters are

E.S.P. Fabric filter, High efficiency cyclone separators etc. For fly ash, the

particle sizes vary from 0.75 microns to 100 micron. In an ESP the dust lidded

gas is passed through an intense electric field, which causes ionization of the

gases & they changed into ion. While travelling towards opposite charged


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electrode, ions get deposited as particles and thus dust is electrically deposited

an electrode.

Figure 3.3

3.2 E.S.P. FIELD WORKING

The field consists of emitting and collecting electrodes structure which are

totally isolated from each other and hanging with the top roof of field. Theemitting electrodes are also isolated from the roof through the support

insulators which also feed the supply to these electrodes. The collecting

electrodes are of the shape of flat plates. Emitting electrodes are of the shape

of spring. The ash depositing on these electrode is wrapped down by separate

wrapping mechanism at the bottom of the field. From the hoppers ash is

evacuated by ash handling system and disposed to the disposal area.


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CHAPTER -4

BOILER

A boiler (or steam generator), one of the major components of the thermal plant is

a closed vessel in which water, under pressure is converted into steam. It is

always designed to absorb maximum amount of heat released in process of

combustion, which is transferred to the boiler by all the three modes of heat

transfer i.e. conduction, convection and radiation.

1.CLASSIFICATION OF BOILERS1.1 FIRE TUBE BOILER

In this type the products of combustion pass through the tubes which are

surrounded by water. These are economical for low pressure only.

1.2 WATER TUBE BOILERIn this type of boiler water flows inside the tubes and hot gases flow outside the

tubes. These tubes are interconnected to common water channels and to steam

outlet.

2.

FEATURES

High evaporation capacity due to availability of large heating surface. Better heat transfer to the mass of water. Better efficiency of plant owing to rapid and uniform circulation of water

in tubes.


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Better overall control. Easy removal of scale from inside the tubes.

In KSTPS, Natural circulation, tangentially fired, over hanged type, Water tube

boilers are used. Oil burners are provided between coal burners for initial start up

and flame stabilization. Firstly, light oil (diesel oil) is sprayed for initialization

then heavy oil (high speed diesel oil) is used for stabilization of flame.

Pulverized coal is directly fed from the coal mills to the burners at the four

corners of the furnace through coal pipes with the help of heated air coming from

PA fan. The pressure inside boiler is negative so as to minimize the pollution andlosses & to prevent the accidents outside the boiler.

This equipment systematically feed fuel to furnace as per load requirement.

The UV flame scanners installed in each of the four corners of the furnace, scan

the flame conditions and in case of unsafe working conditions, trip the boiler and

consequently the turbine.

3. FURNACEFurnace is primary part of the boiler where

the chemical energy available in the fuel is

converted into thermal energy by combustion.

Major factors that assist for efficient

combustion are the temperature inside thefurnace and turbulence, which causes rapid

mixing of fuel and air. In modern boilers,

water-cooled furnaces are used.

4. PULVERISED FUEL SYSTEMFigure 4.1


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The boiler fuel firing system is tangentially firing system in which the fuel is

introduced from wind nozzle located in the four corners

inside the boiler.

The crushed coal from the coal crusher is

transferred into the unit coalbunkers where the coal is

stored for feeding into pulverizing mill through rotary

feeder. Then coal burners are employed to fire the

pulverized coal along with primary air into furnace.

These burners are placed in the corners of the furnace

and they send horizontal streams of air and fuel tangent to an imaginary circle in

the center of the furnace.

4.1 FUEL OIL SYSTEM

The functional requirement of the fuel burning system is to supply a controllable

and uninterrupted flammable furnace input of fuel and air and to continuously

ignite and burn the fuel as rapidly as it is introduced into the furnace. This system

provides efficient conversion of chemical energy of fuel into heat energy. The

fuel burning system should function such that fuel and air input is ignited

continuously and immediately upon its entry into furnace.

Ignition takes place when the flammable furnace input is heated above the

ignition temperature. Ignition energy is usually supplied in the form of heat,

provided by oil guns and by igniters.

5. BOILER DRUMThe drum is a pressure vessel. Its function is to separate water and steam from the

mixture (steam & water) generated in the furnace walls. It provides water storage

Figure 4.2


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for preventing the saturation of tubes. It also houses the equipment needed for

purification of steam. The drum internals reduce the dissolved solids content of

the steam to below the acceptable limit. Drum is made up of two halves of carbon

steel plates having thickness of 133 mm.

Boiler drum is located at a height of 53m from ground. The drum form the part of

boiler circulating system i.e. movement of fluid from the drum to the combustion

zone and back to boiler drum. Feed water is supplied to the drum from theeconomizer through feed nozzles. Water from the drum goes to water walls

through six down comers.

Main parts of boiler drum are:-

Feed pipe Riser tube Down comer Baffle plate Chemical dosing pipe Turbo separation

Figure 4.3


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Screen dryer Drum level gauge

6.DRAFT SYSTEMThe combustion process in a furnace can take place only when it receives a steady

flow of air and has the combustion gases continuously removed. Theoretically

balanced draft means keeping furnace pressure equal to atmospheric pressure, but

in practice the furnace is kept slightly below atmospheric pressure.

6.1 DRAUGHT FANSA fan can be defined as volumetric machine which moves quantities of air or gas

from one place to another. In doing this, it overcomes resistance to flow by

supplying the fluid with the energy necessary for contained motion. The

following fans are used in boiler house:

6.1.1 Primary air fan (P.A. fan) or Exhauster fan

Pulverized coal is directly fed from coal mills to the burners at the four corners of

the furnace through coal pipes with the help of heated air coming from PA fan.

Secondly, this fan also dries the coal.

6.1.2 Forced draught fan (F.D. fan)

The combustion process in the furnace can take place

only when it receives a steady flow of air. This air is

supplied by FD fan. Thus FD fan takes air from

atmosphere at ambient temperature & so provides

additional draught. Its speed is 1500 RPM.

Figure 4.4


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6.1.3 Induced draught fan (I.D. fan)

The flue gases coming out of the boiler are

passed to the ESP & then dust free gases are

discharged up by the chimney to the atmosphere

through the ID fan. Its speed is 745 RPM.

6.2 IGNITER AIR FAN

It is used to provide necessary combustion air to igniter. Two fans are usually

provided. One will run and 2nd will remain as stand by. A control damper is

provided on the discharge which modulates to maintain a constant differential

pressure across igniter when any igniter is in service. Typical speed is 1460 RPM.

6.3 SCANNER AIR FAN

Used to provide necessary cooling air to the flame scanners. Two air fans are

usually provided. One will run and other will remain as stand by. When F.D. fans

trip, the scanner air fan will draw air from atmosphere through emergency

damper. Typical speed 3000 RPM.

7. ECONOMIZERThe flue gases coming out of the boiler carry lot of

heat. An economizer 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

economizer 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

Figure 4.5

Figure 4.6


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

gases flow outside the tubes.

8. HEATERS

8.1 AIR PRE-HEATERS

Air pre-heaters are employed to recover the

heat from the flue gases leaving the

economizer and are used to heat the incoming

air for combustion. This raises the temperature

of the furnace gases, improves combustion

rates and efficiency and lowers the stack (chimney) temperature, thus

improving the overall efficiency of the boiler. Cooling of flue gases by 20%

raises the plant efficiency by 1%.

8.2 SUPER-HEATER

Superheated steam is that steam, which contains more heat than the saturated

steam at the same pressure. This additional heat provides more energy to the

turbine and thus the electrical power output is more.

A super-heater is a device which removes the last traces of moisture

from the saturated steam leaving the boiler tubes and also increases its

temperature above the saturation temperature.

8.3 RE-HEATER

Re-heaters are provided to raise the temperature of the steam from which part of

energy has already been extracted by HP turbine. This is done so that the steam

Figure 1


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remains dry as far as possible through the last stage of the turbine. A re-heater can

also be convection, radiation or combination of both.

9. CIRCULATION SYSTEM

In natural circulation system, water delivered to steam generator from header,

which are at a temperature well below the saturation value corresponding to that

pressure. After header, it is delivered to economizer, which heats it to above the

saturation temperature. From economizer the water enters the drum and thus joins

the circulation system through down covering water wall tubes. In water wall

tubes a part of the water is converted to steam due to boiler and the mixture flowsback to the drum. In the drum, the steam is separated out through the steam

separators and passed to the super heater. After the super heater when the steam

temperature becomes high and pressure up to 150 Kg/cm3 steam is allowed to

enter the turbine to convert potential energy to kinetic energy.

10. SOOT BLOWER

The boiler tubes are cleaned with the help of steam by the process called soot

blowing. We are well known that a greater no. of tubes are presented inside the

boiler. Slowly and slowly the fine ash particles are collected on the tube surface

and from a layer this is called soot. Soot is a thermal insulating material.

There are mainly three types of soot blower are used in KSTPS: -

Water wall soot blower Super heater soot blower Air pre heater soot blower


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11. FUEL SPECIFICATIONS

a) COAL

Type : Slack Coal

Quantity consumed : 20000 tonnes per day

Type of handling : Conveyor

Ash disposal : Wet system

b) OIL

Type : HSD and fuel oil

No. of chimney : 4

Height of Chimney : 180 Meters

Volume of flue Gas : 198 M3/ Sec Air emitted

Temp. of flue gases : 140oC

ESP : One for each unit

12. GENERAL DESCRIPTION

Boilers are tangentially fired; balance draft, natural circulation, radiant type and

dry bottom with direct fired pulverized coal from bowl/ball mills. They are

designed for burning low grade coal with high ash content. Oil burners are

located between coal burners for flame stabilization. Pulverized coal is directly

fed from the coal mills to the burners at the four corners of the furnace through

coal pipes. The pulverized fuel pipes from the mills to the bunkers are provided

with basalt lined bends to reduce erosion and to improve the life of these pipes

owing to poor grade of coal, there is a high percentage of mill rejects. The mill

rejects are conveyed in a sluice way to an under-ground tank. From this tank the


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mixture is taken to an overhead hydro-bin where water is decanted and the mill

reject are disposed off by trucking.

The air required for combustion is supplied by two FD fans.

Three ID fans each of 60% capacity have been provided one ID fan to serve as

standby.

Facilities have been provided to simultaneously unload and transfer 10 light

oil and 40 heavy oil tankers to the designated tanks. Oil preheating arrangement

is provided on the tanks floors for the heavy oil tanks.


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CHAPTER -5

STEAM TURBINE & GENERATION

1.INTRODUCTIONTurbine 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.

Figure 5.1

2.WORKING PRINCIPLEWorking 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, due to


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this fall in pressure a certain amount of heat energy is converted into

mechanical kinetic energy and the steam is set to move 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. It gives rise to change of

momentum and therefore constitutes the driving force of the machine. The

procedure of expansion and direction changing may occur once or a number of

times in succession.

The majority of the steam turbine have, therefore two important

elements. These are-

1. The nozzle in which the system expands from high pressure end is

comparatively in rapid motion to that of lower pressure end.

2. The blades attached to the rotating elements, in which the steam particles

changes its directions and hence its momentum, are attached to the stationary

part of the turbine i.e. stator, casing or cylinder.

Although the fundamental principles of all steam turbine are same, yet the

methods vary and thus certain types of turbines have come into existence.

3.DESCRIPTION3.1 STEAM FLOW

210 MW steam turbine is a compound machine with HP, IP & LP parts. The

HP part is single flow cylinder and IP & LP parts are double flow cylinders.

The individual turbine rotors and generator rotor are rigidly coupled. The HP

cylinder has a throttle control. Main steam is admitted before blending by two

combined main stop and control valves. The IP turbine exhausts directly goes

to LP turbine by cross ground pipes.


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3.2 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. This is suitable for quick start up and loading. The HP turbine consists

of 25 reaction stages. The moving and stationary blades are inserted into

appropriately shaped inner casing and the shaft to reduce leakage losses at

blade tips.

3.3 IP TURBINE

The IP turbine is of double flow construction (double shell construction). The

double flow inner casing is supported kinematically in the outer casing. The

steam from HP turbine after reheating enters the inner casing from above and

below through two inlet nozzles. The arrangements of inner casing confines

high steam inlet condition, 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.

3.4 LP TURBINE

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

have rigidly welded construction. The outer casing is supported by the ends of

longitudinal beams on the base plates of foundation. The double flow inner

casing consists of outer shell and inner shell. The inner shell is attached to

outer shell with provision of free thermal movement. Steam admitted to LP


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turbine from IP turbine flows into the inner casing from both sides through

steam inlet nozzles.

4.ELECTRICITY GENERATION

Thermal power station burns the fuel and use the resultant heat to raise the

steam temperature which drives the turbo-generator. The fuel may be Fossil

(Coal, Oil and Natural Gas) but the object is same to convert the heat into

mechanical energy and further to electrical energy by rotating a magnet inside

the set of winding. In a coal fired thermal power station other raw materials

are air and water.

Meanwhile the heat reloaded from the coal has been absorbed by a long

tube which lies in boiler walls. Inside the tubes Boiler Feed Water is

transferred into turbine blades and makes them rotate. To the end of the turbine

rotor of generator is coupled, so that when turbine rotates the rotor turns with

it. The rotor is housed inside the stator having coil of copper bars in which

electricity is produced through the movement of magnetic field created by

rotor. The electricity passes from the stator winding to the transformer which

steps up the voltage so that it can be transmitted effectively over the power line

of grid.

The steam which has given up its heat energy in changed back into a

condensate so that it is ready for reuse. The cold water is continuously pumpedin condenser. The steam passing around the tubes loose heat and rapidly

change into water. The cooling water is drawn from the river but the Boiler

Feed Water must be pure than potable water (DM Water).

*The rated speed of turbine is 3000rpm.


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CHAPTER -6

WATER TREATMENT PLANT

The principle problem in high pressure boiler is to control corrosion and steam

quality. Internal corrosion costs crores of rupees in repair. Without strict

control, impurities in steam also form deposit over turbine blades and nozzles.

The impurities present in water are as follows:-

Un-dissolved and suspended solid materials.Dissolved slats and minerals.Dissolved gases.Other minerals (oil, acid etc.).

Turbidity & Sediment.

Silica.Micro Biological.Sodium & Potassium Salt.Dissolved Sales Minerals.O2gas.CO2 gas.

Thus to make water pure for feeding in B.F.P. and to have protection against

corrosion and other above mentioned problems de-mineralisation is needed.

The procedure is explained as-


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1.D.M. PLANTIn this plant process, impure water is fed. This plant consists of two streams,

each stream passes through activated carbon filter, weak acid, cation

exchanger and mixed bed exchanger. The impure water is fed to DM plant

through 250 dia. header from it is taken to softening plant. Two filtered water

booster pumps are provided on filtered water line for meeting the pressure

requirement in DM Plant.

Sodium Sulphate solution of required strength is dosed into different

filtered water streams by means of dosing pump to neutralize chlorine prior to

activated carbon filter. Water passes through an activated carbon filter to

remove residual chlorine from water. Water then goes to weak base anion

exchanger unit & enters de-gasified unit where free CO2 is scrubbed out of

water by upward counter flow of low pressure air flow. This de-gasified water

is pumped to strong base exchanger (anion exchanger).

2.C.W. PLANTCirculating water pump house has pumps for condensing the steam for

condenser. After condensing the water is discharged back into the river. Each

of the 5 pumps for 1st

and 2nd

unit has capacity of 8275 M3/Hr, and develop

pressure about 1.94 kg. /Cm2. 3 seal water pumps are used for sealing

circulating water pump shaft at pr. 4.5 kg. /cm2. One pump is taken standby at

a time.

From main line water passes through filter bed to filter the water.

Chlorified water is pumped to 42 m elevation where water is stored in tank and

used for cooling the oil coolers and returns back to river.


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3.B.C.W. PUMP HOUSEFiltered water after demineralization is used for Bearing Cooling from BCW

pump house. Water enters at 30-32oC and leave exchanger at 38

oC. The raw

water used in ash handling plant and remaining quantity is stored in BCW

Pump House. From here the water is pumped to CW pumps. BCW here stand

for water used for cooling oil used for cooling the bearing. In CW pump house

water is discharged from nozzle and impinged for travelling water screens for

cleaning it.


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CHAPTER -7

SWITCH YARD

1.220 KV SYSTEM

Two 220 KV bus bars have been provided in switch yard and are inter-

connected through a bus coupler. Each of the generators is connected to this

system through a step up of 125 MVA 240 / 11 KV yard generator

transformers. There are two step down transformer each feeding 6.6 KV. Each

station transformer has two windings one secondary side and one primary side.

Four feeders take off from 220 switch yard, 2 to SAKATPURA GSS and other2 to HEERAPURA, Jaipur GSS. Each of the four feeders is provided with

bypass isolators which are connected across line breaker and breaker isolator.

A brief description of equipments of 220 KV system is as follows-

1.1 CIRCUIT BREAKERS

Each of generator transformer, station transformer, line feeder and bus coupler

is provided with minimum oil circuit breaker of BHEL make. It is used to

break the circuit either in load condition or in no load condition.

1.2 ISOLATORS

All the isolators are provided in 220KV switchyard and are motor operated.

Triple pole double breaker type and power switch yard , L&T make these and


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are rates for 245 KV and 1250 A. The four isolators are provided with earth

switch.

1.3 CURRENT TRANSFORMER

All the 220 KV current transformers are provided for measuring and

protection. They are BHEL make, single phase, oil filled nitrogen sealed

outdoor type.

1.4 POTENTIAL TRANSFORMER

Each of 220 KV buses is provided with three P.T.S for each phase of BHELmake. There are single phase, oil filled outdoor, N2 sealed magnetic type.

Potential Transformer has two secondary windings on secondary side.

1.5 LIGHTENING ARRESTOR

For protection against lightening, each of line feeders, generator transformer

and station transformer has been provided with three L.A. (one for each

phase). All the L.A. are 2 outdoor types and are rated for 198 KV. The L.A.

of generator transformer and station transformer are located nearby. If we have

to do some work on line, firstly line through earthing isolator is earthed for

discharging the line capacitance and then work is proceeded.


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CHAPTER -8

PROTECTION AND MISCELLANEOUS

1.GENERAL PROTECTIONGenerator is the most important electrical equipment of many generating

station. Tripping of even a generating unit may cause overloading of

associated machines and even to system un-stability. The basic function of

protection applied to generator is to reduce voltage to minimum by rapid

discrimination clearance of faults. Unlike other apparatus the opening of C.B.

to isolate faulty generator is not sufficient to prevent future damage.

2.SPECIFIC PROTECTIONFollowing are the protection purposes for the plant-

1. Field Protection.

2. Pole Slipping.

3. Plane Overload Protection.

4. Inter-turn Fault.

5. Negative Phase Sequence Protection.

6. Reverse Power Protection.

7. Forward Power Protection.

8. Under Frequency & Over Frequency Protection.


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9. Generator Voltage Protection.

10. Rotor Earth Fault Protection.

3. SALIENT FEATURES OF K.S.T.P.S.

1. LOCATION Sakatpura, Kota

2. CAPACITY

i.1st Stage 2x110 MWii.2nd Stage 2x210 MW

iii.3rd Stage 1x210 MWiv.4th Stage 1x195 MWv.5th Stage 1x195 MW

3. SOURCE OF WATER Chambal River

4. PLANT AREA 204 Hectares

5. ASH DUMP AREA 423 Hectares

6. BOILER

i.Type Tangentially fired natural circulation,balance draft, direct fired radiant reheat, and water tube boiler.

ii.No. of units 7iii.Max. Efficiency BHEL (92-95%)iv.Capacity 375 tonnes /Hr.v.Steam Pressure 139 Kg/cm2

vi.Steam Temp. 540oC


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vii.No. of draft fans in servicea. FD fans 2 Units (Each boiler)

b. ID fan 2 Units (Each boiler)viii.No. of Air fans in Service

a. Primary 2 Unitsb. Seal Air fan 1 Unitc. Scanner 1 Unit

ix.No. of coal mills in service 4 Units

x.No. of Soot blower in service 68xi.No. of oil burners 8

7. METHOD OF COOLING

i.Unit # 1-5 Once through cooling systemii.Unit # 6-7 Re-circulation through cooling tower

8. FUELS

i.COALa. Type Bituminous Coal

b. Calorific Value 4450 KCal/Kgc. Qty. Used 3074 tonnes/dayd. Stock yard capacity 5, 00,000 MTe. Average ash content 28-32%f. Sulphur content 0.5%g. Coal crushers 10 Nos.


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h. Type of handling Belt conveyori. Linked coal mines SECL and NCL

ii.FUEL OILa. Type Furnace oil / HSD

b. Available storage capacity FO-18600 KL & HSD- 3100KL9. STEAM GENERATOR BHEL

10. TURBO GENERATOR BHEL


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CHAPTER -9

CONCLUSION

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

an opportunity for encounter with such huge machines like wagon tippler .110

MW & 210 MW turbines and generators.

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 opportunities to lean low technology used at proper place

and time, can save a lot of labour e.g. wagon Tippler (CHP). But there are few

factors that require special mention. Training is not carried out into its tree

sprit.

However training has given us an opportunity to get an exposure of the

practical implementation to theoretical fundamentals.


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SCHEDULE OF THE INDUSTRIAL TRAINING

DURATION -30days (4 June -3 July)

DATE PLANT VISITED

4 June reporting & introductory class

6 June theory class

7 June stage 1(control room)

8 June theory class

9 June stage 1(plant machinery)

10 July theory class11 July coal handling plant (hydraulic)

13 July theory class

14 July coal handling plant (mechanical) & stage 1(C&I)


16 July stage 2(control room) & cooling tower

17 July theory class20 July theory class

21 July stage 2(plant machinery)


25 July stage 4(control room)




29 July stage 5(control room)



1 July theory class

2 July stage 3(plant machinery of a shutdown plant)

Documents

Thermal Report Ankit