This document provides an overview of a summer vocational training project completed by Nikhil Kumar at the Kanti Bijlee Utpadan Nigam Limited power plant in Muzaffarpur, Bihar, India from June 16th to July 15th 2013. The 3-page report acknowledges those who supported and guided the training, and declares that the report was submitted to fulfill degree requirements. It also includes an abstract that briefly outlines the key components and processes involved in a coal-fired thermal power plant.

1. NTPC-AT GLANCE
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PROJECT REPORT
VOCATIONAL TRAINING AT
Kanti Bijlee Utpadan Nigam Limited .
(A Joint Venture Of NTPC Ltd. & BSEB)
Kanti , Muzaffarpur.
FROM 16/06/2013 TO 15/07/2013
UNDER THE GUIDANCE OF:-
 SH. S.S.JHA (MM)
 SH. K.C.TIWARI SR. ENGINEEER (MM)
SUBMITTED TO:- SUBMITTED BY:-
KBUNL,KANTI NIKHIL KUMAR
MUZAFFARPUR,BIHAR MECHANICAL ENGINEERING
NOIDA INSTITUTE OF ENGG. & TECH.
UPTU,UNIVERSITY ROLL NO:-1213340118
BATCH:-2012-2016

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ACKNOWLEDGMENT
It is my pleasure to be indebted to various people, who directlyor indirectly
contributed in the development of this work and who influenced my thunking,
behaviour, and acts during the course of study.
I express my sincere gratitude to Sh.S.S.Jha,AGM (MM) and Sh.S.
Chakarborty,officer HR for providing me an opportunity to undergo summer
training at NTPS-KBUNL, Muzaffarpur.
I am thankful to Sh. K.C. Tiwari, Dy. Sypdt. (MM) for his support, cooperation,
and motivation provided to me during the training for constant inspiration, presence
and blessings.
I also extend my sincere appreciation to Sh. UmeshPrasad and Sh. Manoj
Kumarfor their valuable suggestions and precious time in accomplishing my project
report.
Lastly, I would like to thank the Almighty and my Parents for their moral support
and my Friends with whom I shared my day-to-day experience and receivedlots of
suggestions that improved my quality of work.
SUBMITTED BY:-
NIKHIL KUMAR
B.TECH. (5TH
SEMESTER)
MECHANICAL ENGINEERING
NOIDA INSTITUTE OF ENGG. & TECH.
UPTU,UNIVERSITY ROLL NO:-1213340118
BATCH:-2012-2016

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DECLARATION
I, NIKHIL KUMAR, student of B.Tech. 5th semester,studying at NOIDA
INSTITUTEOF ENGINEERING& TECHNOLOGY, GR. NOIDA
(UPTU), hereby declare that the summer training report on “topic” submitted to
NOIDA INSTITUTEOF ENGINEERING TECHNOLOGY,(GR.
NOIDA)in partial fulfilment of degree of bachelor’s in technology with ME is the
original work conducted by me.
The information and data given in the report is authentic to the best of my knowledge.
This summer training report is not being submitted to any other university for award of
any degree, diploma and fellowship.
SUBMITTED BY:-
NIKHIL KUMAR
B.TECH. (5TH
SEMESTER)
MECHANICAL ENGINEERING
NOIDA INSTITUTE OF ENGG. & TECH.
UPTU,UNIVERSITY ROLL NO:-1213340118
BATCH:-2012-2016

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ABSTRACT
Any thermal power plant is converting the chemical energy of fossil fuel (coal) into
electrical energy. The process involved for this conversion is based upon the Modified
Rankine Cycle. The major components that are used to accomplish the modified
rankine cycle are
 Boiler feed pump,
 The steam generator water walls (evaporator),
 Steam generator super heaters,
 Steam turbine,
 Reheater,
 Condenser,
 Regenerative feed heaters etc.
All components of a power generating cycle are vital and critical in operation. In
Modified Rankine Cycle, the two most important aspects that is added are reheating &
regenerative heating. By reheating we used to send the steamcoming from exhaust of
the turbines back to the reheater of the boiler so that its enthalpy increases and more
work can be done by this steamthe other purpose is to make steam dry so that no harm
will be done to the blades of the turbine.
In NTPC, Kanti, we have three turbines in Tandem coupling namely one H.P Turbine,
one I.P Turbine & one L.P Turbine coupled with the generator to which is
synchronized with the grid to produce electricityat 50Hz.
In all my modesty, I wish to record here that a sincere attempt has been made for the
presentation of this project report. I also trust that this study will not only prove to be
of academic interest but also will be able to provide an insight into the area of technical
management.

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CONTENT
SL NO.
DESCRIPTION
PAGE
NO.
1 An Over-View 6-7
2 Working Process 8
3 Process Of Generation Of Electricity 9-10
4 Generator 11
5 Transformer 12
6 Light Up Process 13
7 Coal Preparation ,Storage & Milling system 14-15
8 Boiler and Auxiliaries 16-22
9 Types Of Pump 23
10 Types Of Turbine 24-25
11 Types Of Cycle 26
12 Types Of Heater 26
13 Flame Scanners 27
14 Important Control Loops In A Thermal Power Plant 27-33
15 Unit Control Desk & Panels 33
16 Advantages Of Coal Based Thermal Power Plant 34
17 Disadvantages Of Coal Based Thermal Power
Plant
34
18 References 35

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AN OVER-VIEW
NTPC
NTPC was set up in 7th November 1975, the MAHARATNA power giant today
generates more than one fourth of the total power in the country, Ranked 5th largest
power generating utility in the world, NTPC is the second most efficient in capacity
utilization among the top ten thermal generating companies according to a survey
conducted by Data Monitor, United kingdom. In a short span of two decades, NTPC
has earned its prime status by setting up a total generating capacity of 22,249 MW.
With 19.14% of India’s operating capacity,the company generates 26.7% of country
electricitythrough its 13 coal and 7 gas based power plants spread all over the country.
STATION AT GLANCE-
Kanti Thermal Power Station is located in Kanti, Muzaffarpur,90 km away from
Patna, the capital of the Indian state of Bihar.It is managed by the Kanti Bijlee Utpadan
Nigam Ltd (KBUN),-a joint venture between NTPC and BSEB Patna.The majority
shares of the Joint Venture Company is hold by NTPC,with NTPC 64.57% and BSEB
35.43%.
First startedin 1985, Kanti Power Plant has an installed capacity of 110×2 MW. An
additional capacity of 195×2 MW is being erectedand is due to be completed by
December 2014.Bihar is the most power stricken state of India; and in the issue of
uplifting our current nation, an excellent and clean 'Thermal Power station' is a
necessity. Kanti thermal Power Plant came into existence in 1985 with the efforts of
then MP of Muzaffarpur, GEORGE FERNANDES.
To take over Muzaffarpur Thermal Power Station (2*110MW), a subsidiary company
named ‘Vaishali Power Generating Company Limited (VPGCL)’ with NTPC on
06/09/2006,-contributing 51% of equity; and the balance equity was contributed by
Bihar State ElectricityBoard. The company was rechristenedas ‘Kanti Bijlee Utpadan
Nigam Limited’ on April 10, 2008.

7. NTPC-AT GLANCE
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WORKING PRINCIPLE
Coal based thermal power plant works on the principal of Modified Rankine
Cycle.
• Process 1-2
• working fluid is pumped from low to high pressure.
• Process 2-3
• high pressure liquid enters a boiler where it is heated at constant pressure by
an external heat source to become a dry saturatedvapor.
• Process 3-4
• The dry saturated vapor expands through a turbine, generating power.
• Process 4-1
• The wet vapor then enters a condenser where it is condensed at a constant
temperature to become a saturatedliquid.
• Process 3-3’
• After the vapor has passed through H.P. it is reheated before passing through
I.P. turbine.
• this prevents the vapor from condensing during its expansion which can
seriously damage the turbine blades, and improves the efficiency of the
cycle

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PROCESS OF GENERATION OF ELECTRICITY
NTPC, Kanti is a Thermal Power Plant. The functioning of every thermal power plant
is based on the following processes: -
1. Coal To Steam.
2. Steam To Mechanical Power
3. Power Generation, Transmission & Distribution.
STEP-1
 Coal To Steam
Coal and Water are primary inputs to a
thermal power plant. This process of
conversion of water to steam by using the
heat energy produced by burning coal for
producing heat takes place in the boiler
and its auxiliaries.Coal burns in a furnace
located at the bottom part of the boiler. Feed
water is supplied to the boiler drum by boiler
feed pumps, where water is heated and converted into saturatedsteam
This is further superheated in the super heaters.
STEP-2
 Steam To Mechanical Power
This is the most important process of a power plant. The superheated
Steam produced in the boiler at high pressure and temperature is feed
to the turbine. The steam expands in the turbine giving up heat energy, which is
transformed into mechanical energy on turbine shaft. Thus,
Mechanical power is obtained from the turbine shaft.
TURBINE

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STEP-3
Power Generation, transmission &
Distribution
Mechanical power produced at the shaft of the turbine is used to
rotate the rotor of an electrical generator that produces electric
power. The electric power produced by the generator is boosted to a
higher voltage by a generator transformer to reduce the transmission
losses.
This power at EHV i.e. 400 kV is transmitted and distributed by EHV
transmission lines.
Schematic Diagram of a Thermal power station
RIVER

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GENERATOR
Rating
Active Output
Continuous
110MW
Rated Voltage 11000+/-5%V
Rated Current 7220 A
Power Factor 0.8 lagging
Frequency
50 Hz
Excitation System Static type
Field current at rated output 1335 A
Type of coolingsystem Hydrogen Cooled
Hydrogen Pressure 2 Ata
No. Of H₂ cooled elements 06
Coolingmedium for H₂ Soft water

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TRANSFORMER
A transformer is an electrical device which works on the principle of mutual induction.
The autotransformer used in power station. It has three windings primary, secondary
and tertiary. The 220kv voltage is fed as input to primary by step down 132kv fed
MTPS as input.
The output of generator is step up to 220kv by using step up transformer or generating
transformer. Three phase is fed to station transformer. There are two station
transformer1 and 2 which is step down transformer. Here 220kv is step down to 6.6kv
for internal purpose. This 6.6kv is step down to 415v for low rating motors. At
generating transformer we are using lighting arrestor which protects G.T from lighting.
This 220kv is given to grid substation. In grid substation we are using some protective
system before distribution we have Bus isolator, SF6 breaker, Line isolator, CT,
lightning arrestor. Similarly we have two unit auxiliary transformer UAT-1 and UAT-
2, which will step down voltage from 11kv to 6.6kv and it will supply to unit auxiliary
board 1BA, 1BB. Similarly station transformer will supply to station board 9BA, 9BB.
One unit is tie with other unit because during the failure of any one of the unit other
unit will able to supply.

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LIGHT UP PROCESS
• STEP-1
• A controlled quantity of crushed coal is fed to each bowl mill (pulveriser) by
its respective feeders and primary air is supplied from the primary air fans
which drives the coal as it is being pulverized and transports the pulverized
coal through the coal piping system to the coal burner.
• STEP-2
• The pulverized coal and air discharge from the coal burners is directed
towards the centre of furnace to form fire ball.
• STEP-3
• The secondary air heating system supplies secondary air for combustion in
the furnace around the pulverized coal burners and through auxiliary air
compartments ,directly adjacent to the coal burner compartments.
• STEP-4
• Above a predictable minimum loading condition, the ignition becomes self-
sustaining. Combustion is completed as the gases spiral up in the furnace.

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Components of Coal Fired Thermal Power Station:
 Coal Preparation
i)Fuel preparation system: In coal-firedpower stations, the raw feedcoal from the
coal storage area is first crushed into small pieces and then conveyed to the coal feed
hoppers at the boilers. The coal is next pulverized into a very fine powder, so that coal
will undergo complete combustion during combustion process.
Pulverizer: is a mechanical device for the grinding of many different types of
materials. For example they are used to pulverize coal for combustion in the steam-
generating furnaces of fossil fuel power plants. There are six mills located adjacent to
the furnace at 0 m level .These mills pulverize coal to desired fineness to be fed to the
furnace for combustion.
The main structure of the pulverisering mill is fabricatedfrom mild steel in three
cylindrical sections, the bottom section (the mill housing support )which support the
entire unit and encloses the mill drive gear unit, a center section (the mill housing)that
contains the rotary grinding element and upper section (the classifier housing
)comprising an accommodate the gas loading cylinders of the mill loading gear .A
platform around the upper section provide an access to an inspection door and to the
top of the mill routine maintenance and is served by detachable ladder .
The grinding element comprises of 3 rotatory rollers.
Types of Pulverisers: Ball and Tube mills; Ring and Ball mills; MPS; Ball mill;
Demolition.
ii)Dryers: They are used in order to remove the excess moisture from coal mainly
wetted during transport. As the presence of moisture will result in fall in efficiency due
to incomplete combustion and also result in CO emission.
iii)Magnetic separators: Coal which is brought may contain iron particles. These iron
particles may result in wear and tear. The iron particles may include bolts, nuts wire
fish plates etc. so these are unwanted and so are removed with the help of magnetic
separators.

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The coal we finally get after these above process are transferred to the storage site.
Purpose of fuel storage is two –
 Fuel storage is insurance from failure of normal operating supplies to arrive.
 Storage permits some choice of the date of purchase, allowing the purchaser to
take advantage of seasonal market conditions. Storage of coal is primarily a
matter of protection against the coal strikes, failure of the transportation system
& general coal shortages.
There are two types of storage:
1. Live Storage(boiler room storage): storage from which coal may be
withdrawn to supply combustion equipment with little or no remanding is live
storage. This storage consists of about 24 to 30 hrs. of coal requirements of the
plant and is usually a covered storage in the plant near the boiler furnace. The
live storage can be provided with bunkers & coal bins. Bunkers are enough
capacity to store the requisite of coal. From bunkers coal is transferred to the
boiler grates.
2. Dead storage- stored for future use. Mainly it is for longer period of time, and it
is also mandatory to keep a backup of fuel for specified amount of days
depending on the reputation of the company and its connectivity.There are
many forms of storage some of which are –
1. Stacking the coal in heaps over available open ground areas.
2. As in (I). But placed under cover or alternativelyin bunkers.
3. Allocating special areas & surrounding these with high reinforced
concerted retaking walls.

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BOILER AND AUXILIARIES
A Boiler or steam generator essentially is a container into which water can be fed and
steam can be taken out at desired pressure, temperature and flow. This calls for
application of heat on the container. For that the boiler should have a facility to burn a
fuel and release the heat. The functions of a boiler thus can be stated as:-
1. To convert chemical energy of the fuel into heat energy
2. To transfer this heat energy to water for evaporation as well to steam for
superheating.
Salient Features Of Boiler Plant:-
1. General
a) Type of boiler Single drum tangentialfiring &
reheattype.
b) Type of fuelused Pulverized coal(MainFuel) Heavy oil& L.D.O. (for lightup
& flame stabilization)
c) No. of Mills 6
d) Type of Mills Pressurized type BowlMill
e) Furnace Balanced draught
f) P.A. Fans 2 nos. (each 60% capacity)
g) F.D. Fans 2 nos. (each 60% capacity)
h) I.D. Fans 3 nos. (one standby)
(each 60% capacity)
i) Air Heater 2 nos.
j) Type of Air Heater Trisector regenerative
k) Electrostatic Precipitator 1 nos.

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2. M.C.R. Parameter M.C.R. Value
a) S.H. OutletSteam Flow 375 T/Hr
b) R.H. Steam Flow 331 T/Hr
c) Pressure atS.H. Outlet 141.5 Ata
d) Temp. atS.H. Outlet 540ºC
e) Pressure atR.H. Inlet 37 ata
f) Pressure atR.H. Outlet 32.9 ata
g) Temp. atR.H. Inlet 369ºC
h) Temp. atR.H. Outlet 540ºC
i) Pressure in Drum 148.69 ata
j) Design Pressure 158.0 kg/cm
k) Flue Gas temp. leaving
Economiser 350ºC
l)Flue Gas temp. Leaving
Air Heater 142ºC
m) Feed Water Temp. Before
Economizer 235ºC
The basic components of Boiler are: -
 Furnace
 Economiser
 Air Preheater

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 Super Heater
 Reheater
 Desuperheaters
 Condenser
 Cooling tower
 Fan or draught system
 Ash handling system
• FURNACE
A boiler furnace is the first pass of the boiler in which fuel is burned and from which
the combustion products pass to the super heater and second pass of boiler.
The combustion process is a continuous process, which takes place in first pass of the
boiler and controlled by fuel input through coal feeders.It is a radiant type and water-
cooled furnace and enclosure is made up of water wall.
The furnace is open at the bottom to allow ash/clinkers to fall freelyinto the furnace
bottom ash hopper (through a ‘furnace throat’), and at the top of its rear wall, above the
arch, to allow hot gases to enter the rear gas pass.
The basic requirements that a furnace must satisfyare:
1. Proper installation, operation and maintenance of fuel burning equipment.
2. Sufficient volume for combustion requirements.
3. Adequate refractories and insulation.
• ECONOMISER
It is locatedbelow the LPSH in the boiler and above pre heater. It is there to improve
the efficiencyof boiler by extracting heat from flue gases to heat water and send it to
boiler drum.
Advantages of Economiser include
1) Fuel economy: – used to save fuel and increase overall efficiencyof boiler plant
2) Reducing size of boiler: – as the feed water is preheated in the economiser and enter
boiler tube at elevatedtemperature. The heat transfer area required for evaporation
reduced considerably.

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 AIR PREHEATER
The heat carried out with the flue gases coming out of economiser are further utilized
for preheating the air before supplying to the combustion chamber. It is a necessary
equipment for supply of hot air for drying the coal in pulverized fuel systems to
facilitate grinding and satisfactorycombustion of fuel in the furnace
• SUPERHEATER
The steamgenerated by the boiler is usually wet or at the most dry saturatedbecause it
is in direct contact with water.So, in order to get superheated steam,a device known as
superheater has to be incorporated in the boiler.
The function of the superheater system, is to accept dry saturatedsteam from the steam
drum and to supply superheated steamat the specifiedfinal temperature of 540oC, by
means of a series of heat transfer surfaces arrangedwithin the boiler gas passes.
A superheater is a surface type heat exchanger generally located in the passage of hot
flue gases. The dry saturatedsteam from the boiler drum flows inside the superheater
tubes and the hot flue gases flows over the tubes and in this way its temperature is
increasedat the same pressure.
The super heater consists of three sections classifiedas primary super heater,
secondary super heater and final super heater. In Kanti, there are 14 super heater coils
which are divided into above different sections where temperature is increasedfrom
approx. 340oC to 540oC
 REHEATER
Power plant furnaces may have a reheater section containing tubes heated by hot flue
gases outside the tubes. Exhaust steam from the high pressure turbine is rerouted to go
inside the reheater tubes to pickup more energy to go drive intermediate or lower
pressure turbines.
• DESUPERHEATERS
A. Superheater Desuperheater
The superheater desuperheater is fittedafter 10th coil to control the superheated

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steamat the specified terminal temperature of 540˚C. The maximum design
temperature reduction at the superheater desuperheater is from 446˚C to 388˚C.
B. Reheater Desuperheater
The reheater desuperheater is only brought into use when the reheater outlet
temperature rises above the normal temperature.
 CONDENSER
The condenser condenses the steam from the exhaust of the turbine into liquid to allow
it to be pumped. If the condenser can be made cooler, the pressure of the exhaust steam
is reduced and efficiencyof the cycle increases.The functions of a condenser are:-
1) To provide lowest economic heat rejection temperature for steam.
2) To convert exhaust steam to water for reserve thus saving on feed water
requirement.
3) To introduce make up water.
We normally use surface condenser although there is one direct contact condenser as
well. In direct contact type exhaust steam is mixed with directly with D.M cooling
water.
 COOLING TOWER
The cooling tower is a semi-enclosed device for evaporative cooling of water by
contact with air. The hot water coming out from the condenser is fed to the tower on
the top and allowed to tickle in form of thin sheets or drops. The air flows from bottom
of the tower or perpendicular to the direction of water flow and then exhausts to the
atmosphere after effective cooling.
The cooling towers are of four types: -
1. Natural Draft cooling tower 2. Forced Draft cooling tower
3. Induced Draft cooling tower 4. Balanced Draft cooling tower

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• FAN OR DRAUGHTSYSTEM:
In a boiler it is essential to supply a controlled amount of air to the furnace for
effective combustion of fuel and to evacuate hot gases formed in the furnace
through the various heat transfer area of the boiler. This can be done by using a
chimney or mechanical device such as fans which acts as pump.
i) Natural draught
When the required flow of air and flue gas through a boiler can be obtained by the
stack (chimney) alone, the system is called natural draught. When the gas within the
stack is hot, its specific weight will be less than the cool air outside; therefore the unit
pressure at the base of stack resulting from weight of the column of hot gas within the
stack will be less than the column of extreme cool air. The difference in the pressure
will cause a flow of gas through opening in base of stack. Also the chimney is form of
nozzle, so the pressure at top is very small and gases flow from high pressure to low
pressure at the top.
ii) Mechanized draught
There are 3 types of mechanized draught systems
1) Forced draught system 2) Induced draught system
3) Balanced draught system
Forced draught: – In this system a fan called Forced draught fan is installed at the
inlet of the boiler. This fan forces the atmospheric air through the boiler furnace and
pushes out the hot gases from the furnace through superheater, reheater, economiser
and air heater to stacks.
Induced draught: – Here a fan called ID fan is provided at the outlet of boiler, that is,
just before the chimney. This fan sucks hot gases from the furnace through the
superheaters, economiser, reheater and discharges gas into the chimney. This results in
the furnace pressure lower than atmosphere and affects the flow of air from outside to
the furnace.

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Balanced draught:-In this system both FD fan and ID fan are provided. The FD fan is
utilized to draw control quantity of air from atmosphere and force the same into
furnace. The ID fan sucks the product of combustion from furnace and discharges into
chimney. The point where draught is zero is calledbalancing point.
• ASH HANDLING SYSTEM
The disposal of ash from a large capacity power station is of same importance as ash is
produced in large quantities. Ash handling is a major problem.
i) Manual handling: While barrows are used for this. The ash is collected directly
through the ash outlet door from the boiler into the container from manually.
ii) Mechanical handling: Mechanical equipment is used for ash disposal, mainly
bucket elevator, belt conveyer. Ash generated is 20% in the form of bottom ash and
next 80% through flue gases, so calledFly ash and collectedin ESP.
iii) Electrostatic precipitator: From air preheater this flue gases (mixed with ash)
goes to ESP. The precipitator has plate banks (A-F) which are insulated from each
other between which the flue gases are made to pass. The dust particles are ionized and
attractedby charged electrodes.The electrodes are maintained at 60KV.

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TYPES OF PUMP
1. Condensate Extraction Pump (CEP)
The function of Condensate extraction pumps is to pump out the condensate to the
deaerator through, LP heaters.The steamfrom the LP cylinders exhausts into the
condenser shells where it is constrained to flow across the water tubes, through which
cooling water is circulated.
There are two 100% duty extraction pumps, one remains in duty and one remains stand
by. The thrust bearings in the driving motors have temperatures sensor, which can trip
the motors automatically. The pump discharge the condensate to the LP heater system
with a pressure increasedto approx. 18 kg/sq. cm from 70-75 mm of Hg.
2. Air Extraction Pump (AEP)
The function of the air extraction pump is to raise and maintain the vacuum conditions
in the turbine main condensers, and to remove air and other non-condensable gases
vented to the condenser from various parts of the turbine and feedwater heating
system.
3. Boiler Feed Pump (BFP)
Boiler feed pump is the most critical component of a power plant. It is a rotary
machine, which is coupled to a motor through variable speed coupling or turbo
coupling.
Feed water suppied to the boiler drum should have high pressure which is achieved
when passed through boiler feed pump. Whenever the pressure of water is to be raised,
BFP is used. The discharge pressure of a boiler feed pump is approx. 150 kg/sq. cm.

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TYPES OF TURBINE
High pressureturbine
• It is of single flow design with eight stages of blading.
• Each stage has moving and stationary blades.
• Superheated steam(at 1100⁰c) from boiler drum enters in to it.
• Speed-3000rpm
Intermediatepressureturbine
• Double flow design with seven stages of blading on either side.
• Each stage has moving and stationary blades.
• Reheated steam(at 535⁰ c) from H.P turbine outlet enters in to it.
• Speed-3000rpm
Low pressureturbine
• It is also of double flow design with 6 stages in front and rear flow
paths.
• Each stage has moving and stationary blades.
• Stem out of I.P. turbine directly enters in to it.
• Speed-3000rpm

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 Salient Feature Of Turbine:-
1. General
a) Type Of Turbine Reheat
b) No. Of Cylinders 3 (HP,IP & LP)
c) No. Of LP Heater 5
d) No. Of HP Heater 2
e) Deaerator 1 (Variable pressure type)
f) No. Of Extraction pump 3 (one standby)
g) No. Of BFP 2 (one standby)
2. M.C.R. Parameter M.C.R. Value
a) Rated output 110 MW
b) M.S. Pressure atH.P. turbine inlet 130 ata
c) M.S. temp. atH.P. turbine inlet 535oC
d) H.R.H. temp. atI.P. turbine inlet 535oC
e) Turbine speed 3000 rpm
f) Condenser Vacuum 0.1 kg/cm2 (abs)
g) No. of Extraction 7
h) Quantity of cooling water 15,400 m3/hr

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TYPES OF CYCLE
1. Steam Cycle
Drum↔ Steam Heater↔ High Pressure Turbine
↕
Intermediate Pressure Turbine↔ ReHeater
↕
Low Pressure Turbine↔Condenser
2. Water Cycle
Hotwell↔ Condensate Extraction Pump ↔ Low Pressure
Heater↔ Deaerator
↕
Drum↔ Economizer↔ High Pressure Heater↔Boiler Feed Pump
3. Flue Gas Cycle
Furnace↔ Steam Heater↔ ReHeater↔ Economizer
↕
Chimney ↔Electrostatic Precipitator ↔ Air Preheater
TYPES OF HEATER
1. High Pressure Heater (HPH)
In the water cycle, temperature of feed water from BFP is increasedto approx. 130oC
by heating it in HP heater. As the heating of the feed water in HP heater is done by the
extra steamcoming out of the High Pressure Turbine(HPT) hence, it is named as High
Pressure Heater(HPH).
2. Low Pressure Heater (LPH)
In the water cycle, temperature of condensate from CEP is raised to approx. 80oC by
heating it in LP heater. As the heating of the condensate in LP heater is done by the
extra steam coming out of the Low Pressure Turbine(LPT) hence, it is named as Low
Pressure Heater(LPH).

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FLAME SCANNERS
In a flame there are three zones.
1.Visible zone
2. UV zone
3.Infrared zone
The flame scanner consists of UV light sensitive tube and UV light sensitive element
filled inside the tube on which 700 DC volt is supplied.
Initially there is no contact between the two electrode on which 700 DC volt is
supplied. As there is UV light sensitive element present inside the tube, it sacns the UV
zone of the flame.When it scans the UV zone, the UV element present inside the tube
conducts and the two electrode are in contact. Now, the supplied voltage is reduced to
zero. Hence, whenever it scans the UV zone, the supplied voltage becomes 0V
otherwise it is 700V. Therefore, on an average the scanner shows 400V – 450V which
confirms the presence of flame inside the furnace.
As there are two types of fuel which are the main source of burning. Hence, basically
there are two types of flame scanners depending upon the fuel used. So, to sense the
flame due to oil used in the furnace there are oil flame scanners and to sense the flame
due to coal used are known as coal flame scanners.
IMPORTANT CONTROL LOOPS IN A THERMAL POWER PLANT

Basic Block Diagram Of Any Closed Control Loop

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Process:The equipment whose present level, pressure and other values is to be
measured is known as process.
Set Point: The required value of parameter is set by the manual which is to be
maintained in order to protect the process from damage.
Measurement: The present value of parameter in process is measured here.
Generally, capacitance type of measurement is used.
Two tapping from the process, one at high pressure & other at low pressure, is taken
and transmitted through isolating diaphragm and silicon oil fill fluid to a sensing
diaphragm in the centre of the differential pressure cell.The sensing diaphragm
deflects in response to differential pressure. The position of the sensing diaphragm is
deflectedby capacitor plates on both sides of the sensing diaphragm. The differential
capacitor between the sensing diaphragm and the capacitor plate is converted
electronicallyto a 4-20 mA signal and transmittedto comparator. This measurement
sometimes also known as transmitter.
Comparator: It compares the signal between set point and measured value. If the
two values differ from one another, an error signal is generated and sent to the
controller.
Controller: It is an electronic card which, according to the error signal sent by
comparator, gives a current signal between 4-20 mA to final control element.
Final Control Element: It is that portion of the loop which directly changes the
value of the manipulated process variable and finally do some work to maintain the set
point of the process.
1.Drum Level Control

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The required drum level is set at the set point. The present drum level is then measured
which is done by capacitor type transmitter.Two tapping, one at the bottom in water
while other at the top in steam, is made and allowed to flow to the transmitter.Since,
the two elements are in different states,steamis condensed and collectedin a constant
head unit (CHU) before going to the transmitter where the present drum level is
measured and converted to current signal between 4-20 mA. This set value and
measured value are then compared in a comparator and an error signal, if any, is
generated and sent to controller which finally directs the final control element to
control the drum level. Here, the final control element is a control valve through which
a fluid passes that adjusts the size of the flow passage as directed by a signal from
controller to modify the rate of flow of the fluid. Hence, the drum level is controlled.
2. D.P. Across Feed Control Station
In order to maintain the linear characteristics of the feed regulating valves under
different loads, the differential pressure(D.P.) control loops maintains a fixed
differential across the regulating valves and BFP discharge pressure is varied by

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changing BFP motor speed through hydraulic scoop tube device which is the final
control element here. The D.P. across feed station (comparator) is sensed and is fed to
the controller. The controller are automatically adjusted as function of steam flow to
achieve stable condition. The reserve Boiler Feed pump scoop tube automatically
follows the running pump scoop tube and the changeover to the reserve BFP takes
place with the scoop tube in the same position of the scoop tube.
3. Combustion Control
The combustion control proposed for this boiler comprises of the following loops:
a. Master pressure control
b. Pulverized coal flow control
c. Combustion air flow control
d. Oxygen trimcontrol
e. Mill temperature and air flow control
a. MasterPressure Control
The turbine throttle pressure which is a measure of turbine and boiler mismatch, is
maintained by proper fuel and air flow control to the burners. Actual steam pressure at
turbine inlet is measured and error against a set value is fed to the individual pulveriser
control loop through controller.
b. Flue Flow Control
In order to maintain an air rich furnace, air flow demand signal is superimposed over
total fuel flow signal through a high limiter unit. This way when master demand signal
increases and if air flow is low, fuel flow is not straightaway increased. Instead, main
demand signal first increases the air flow and only when demand signal is low as
compared to air flow, tie selector unit in the fuel control loop increases the fuel flow.
When the master demand calls for a reduction of combustion, fuel flow and air flow
are reduced simultaneously with fuel flow leading air flow, thus ensuring always an air
rich furnace.
c. Combustion Air Flow Control

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Total air flow signal is fed to control and this controller output adjusts the FD fan
vanes. Provision also exists to ensure a minimum air flow (30% of maximum) through
a high signal selector.
d. Oxygen Trim Control
To ensure some percentage of excess air for optimum combustion, Oxygen trim control
is employed. Oxygen contain in flue gas before air preheater is measured and error is
fed to controller. A maximum/minimum limiter is introduced so that should the oxygen
supply fall, a minimum disturbance is introduced in the flue/air control loop.
e. Mill Temperature And Flow Control
This control loop is envisaged to maintain constant air flow to the mills and also to
maintain constant mill outlet temperature. Primary air flow and mill outlet temperature
signals are measured and fed to the controller respectively.Output of the controllers
are connected to each of the two error modules, the output of which are going to coal
and hot air dampers through respective auto manual stations. The provision of variable
air flow supply exists in the hardware supplied and shall be adopted on site,if required.
4. Furnace Draft Control
The furnace draft is maintained by modulating the I D fan Hydraulic coupling (3 nos.).
Furnace draft at combustion chamber outlet is measured and the error is fed to the
controller. Output of this controller accordingly positions the vanes to maintain
constant furnace pressure to improve the system dynamic response. An anticipator total
air flow signal is alsoadded in the loop.
5.Primary Air Header Pressure Control
A control loop always ensure sufficient PA to the pulveriser hot air duct at the set
pressure and achieves the same by modulating the PA fan vanes (2 nos.).

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6. Superheat Steam Temperature Control
The superheater steam temperature control system makes use of three parameters,
secondary superheater outlet temperature,total steam flow and superheater inlet
temperature. The final superheaters temperature error is fed to controllers which
positin spray control valves left & right sides to maintain constant superheater outlet
temperature.
7. Reheat Steam Temperature Control
Reheat outlet steam temperature is maintained by tilting the burner to increase/decrease
heat absorption in the reheat section of the boiler. Additional emergency reheat spray is
used to maintain temp. when burner tilts are unable to reduce the temp. sufficiently.
Left and right reheater temp. signals are averaged and fed to controller. Controller
output is indexed with total steam flow signal and through an auto-manual station
drives nozzle tilt drive. In case of differential reheater temp. difference above
allowable limits, respective spray control valve left or right are used to bring balance in
left and right side R.H. steamtemperatures.
8. BFP Minimum Flow Recirculation Control
In order to ensure safetyof the pump against overheating, the minimum flow is to be
maintained when the pump flow reduces below a preset limit. This is achieved by a
reliable pneumatically operated minimum flow recirculationcontrol valve with built-in
pressure breakdown device. The control envisaged is an on-off control, the operation
of which is initiatedby a low range DP switch sensing the boiler feed pump flow.
Whenever the flow falls below 100 T/hr., the minimum circulation valve is opened and
when the flow increases above 200 T/hr., this valve is kept closed. Indication is
provided on the UCB to indicate the operator the status of this valve by open-close
position indication lamp.
9. Hotwell Level Control :-Hotwell level is maintained by recirculationof the
condensate after steamjet air ejector through a level controller and split-range control
valves. Any excess condensate is, therefore, fed to the deaerator.

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10. Deaerator High & Low Level Control
The deaerator low level control acts on the condenser make-up control valve to add
DM water in the hotwell and the high level control acts on the excess condensate to
Unit condensate floating tank. Two separate control loops have been provided for the
above.
11. Secondary Air Damper Controls
The function of a secondary air damper control system is to distribute the secondary air
from the windbox requirements. Electronic analog control system is used for this
application. Duplicate transmitters of 4-20 mA dc output for Heavy oil and
furnace/wind box differential pressure are used to improve system availability. The 4-
20 mA dc output from the control system is converted into pneumatic signal using E/P
signal converter to position power cylinder operated dampers at all the elevations on
four corners. Electric to pneumatic (E/P) signal converters are field mounted type.
UNIT CONTROL DESK & PANELS
The operation of each unit is envisaged from the central unit control room. It is located
in the control bay at 9.0m TG floor. It is adequately illuminated and is centrallyair
conditioned. For operational convenience, the control room front wall has complete
glass paneling for TG hall view and the two double doors for entry from TG hall.
The control board has a special profile with three sloping surfaces for mounting a large
facias, instruments and controls. The automatic control station and drive contrl
switches & Indications are located on the first sloping surface. The process
indicators/recorders and ammeters are mounted on the second sloping surface and the
alarm annunciation window facias are mounted on the top i.e. third sloping surface.
The unit control board are arranged in logical operating sequence from the left to right
starting with (i.)Air & Flue Gas, (ii.)Fuel oil, (iii)Bowl Mills, (iv)Steam & Feed water,
(v)Regenerative System, (vi)Turbine and (vii) Generator.

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ADVANTAGES OF COAL BASED THERMAL POWER PLANT
 They can respond to rapidly changing loads without difficulty
 A portion of the steam generated can be used as a process steam in different
industries
 Steam engines and turbines can work under 25 % of overload continuously
 Fuel used is cheaper
 Cheaper in production cost in comparison with that of diesel power stations.
DISADVANTAGES OF COAL BASED THERMAL POWER PLANT
 Maintenance and operating costs are high
 Long time required for erection and putting into action
 A large quantity of water is required
 Great difficulty experienced in coal handling
 Presence of troubles due to smoke and heat in the plant
 Unavailability of good quality coal
 Maximum of heat energy lost
 Problem of ash removing
REFERENCES:

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‘Modern power station practice-Volume-B.
-Volume-C.
‘ Power plant Engg.’ By P.K.NAG
Control & Instrumentation-Volumel
Operation & Maintenance Manual (MTPS)-Volume H
 Wikipedia
 www.ntpc.cpo.in
 http://indianpowersector.com/home/power-station/thermal-power-
plant/

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SUBMITTED TO:- SUBMITTED BY:-
KBUNL,KANTI NIKHIL KUMAR
MUZAFFARPUR,BIHAR MECHANICAL ENGINEERING
NOIDA INSTITUTE OF ENGG. & TECH.
UPTU,UNIVERSITY ROLL NO:-1213340118
BATCH:-2012-2016