NTPC UNCHAHAR PROJECT REPORT ON BOILER AND TURBINE MECHANICAL

1. SUMMER TRAINING PROJECT REPORT
ON NTPC UNCHAHAR (U.P)
SUBMITTED TOWARDS COMPLETION OF VOCATIONAL
TRAINING AT NTPC UNCHAHAR
UNDER THE GUIDANCE OF: -
 Shri Sanjeev Kumar (AGM, BMD)
 Shri Madhur Kuma (AGM,TMD)

2. SUBMITTED BY:-
ANKUR PAL
B. TECH MECH. (4th
SEM) DAV UNIVERSITY
CERTIFICATE
This is to certify that this summer training report has
been prepared by MR. ANKUR PAL S/O SHRI R.P
PAL, a student of MECHANICAL ENGINEERING
(DAV UNIVERSITY) in the partial fulfillment of
requirement of vocational training at NTPC
UNCHAHAR.
The matter was analyzed by candidate under my
guidance and this report embodies the work done by him.
We wish him a bright future.
PROJECT GUIDE :-
SHRI P.S PANDEY (BMD)
Ms. SARDA NANDA (TMD)

3. ACKNOWLEDGEMENT
With feelings of joy and thanks, I placed in your hand
my Project report. It is my pleasant privileges to thank
all those who have help me in molding and shaping my
project. Without their guidance, cooperation and best
wishes it would have been impossible for me to
complete my dissertation report. A big thanks to all
those who helped me by sparing time amidst their busy
schedule and for being kind enough to help me
whenever I needed them.
“As man is a social animal.” He requires the
encouragement and affection of his parents and friends
to accomplish his goal and I have been Lucky to get it
and make this project report a success.
Finally, I am thankful to all the respected Executive
employees of N.T.P.C UNCHAHAR for providing me
the necessary information, cooperation in VOCATINAL
TRAINING. I thank god almighty for his abundant
blessing because without it this project was only a
dream.
THANKING YOU
ANKUR PAL

4. INTRODUCTION
NTPC Limited is the largest thermal power
generating company of India. A publicsector
company, it was incorporated in the year 1975 to
acceleratepower development in the countryas a
wholly owned company of the Government of
India. At present, Government of India holds
89.5H% of the total equity shares of the company
and the balance 10.5%is held by FIIs, Domestic
Banks, Public and other. Within a span of 40 years,
NTPC has emerged as a truly national power
company, with power generating facilities in all the
major regions of the country. NTPC’s core
business is engineering, construction and operation
of power generating plants. It also provides
consultancyin the area of power plant
constructionsand power generation to companies
in India.

5. THERMAL POWER PROJECT (FGUTPP)
• Foundation stonewas laid by Late Prime
Minister Mrs. Indira Gandhi in June 1981.
• First two units of 210MWwere commissioned
on 21st
November, 1988 and 22nd
March, 1989
by U.P. Rajya Vidyut Utpadan Nigam.
• FGUTPP was handed over by U.P. Rajya
Vidyut Utpadan Nigam to NTPC in 13th
February, 1992.
• After takeover of FGUTPP from UPRVUN to
NTPC, unit-3, unit-4 and unit-5 were
commissioned on 27th
January1999, 22nd
October 1999 and 2006 respectively.
NTPC has been ranked first as per total income in
the power generation, transmission, distribution
sector among India’s top 500 companies for the
year 2006 by Dun and Bradstreet.

6. LAYOUT OF THERMAL POWER PLANT

7. PrincipleoftheSteamPowerPlant
The Working Principle of a steam plant is based
upon the Rankinecycle. Generallysteam is taken as
the working medium due to its ability to be stable
and that it’s readily stable. The flow of steam in the
plant can be very easily be understoodby the flow
diagram of the plant. A graph plottedbetween the
temperatureand the entropywould indicate the
technical details of the working by the Rankin
cycle

8. MODIFIED RANKINE CYCLE
AB- Heating of feed water (i.e. sensible heat addition)
BC- Evaporation of water in boiler (i.e. latent heat addition)
CD- Superheating of steam (i.. heat addition)
DE- Isentropic expansion of steam in HP turbine
EF- Reheating of steam in Reheaters
FH- Isentropic expansion of steam in IP and LP turbine
HA- Condensation of steam in the condenser
Point G-Demarcation between superheated and wet steam
In order to achieve the high efficiency, the following points
should be kept in mind:
• The value of useful heat or the temperature of useful heat
should be high.
• The value of rejected heat or the heat of rejection
temperature should be low
To increase the boiler efficiency following methods are used:
• Reheating and Feed water heat
• Superheating

9. The fuel used in the thermal power plantsin the
boiler furnace is coal. Coal undergoes various
processes like separation, crushing, etc. and is then
finally moved to the furnace in the form of
pulverised coal.
COAL: It is a mixture of organic chemicals and
internal materials producedby natural process of
growth and decay. The chemical propertiesof any
col depend upon the proportionsof different
chemicals componentspresent in it. There are four
types of coal:
Peat
Lignite
Bituminous
Anthracite

10. In the plant we use Bituminous coal which is one
of the most important variety of coal, being soft
and widely used as fuel. Its approximate
composition is
• C= 85%
• H =5%
• O2 =7%
• Gross calorific value = 3000-4000
The rest is comprised of sulphur,phosphorus,
sodium and other minerals in traces. Basically the
coal used in the plant contains carbon, some
volatile material, moisture and ash. The ash content
in the coal is around 30- 40 %.

11. BOILER

12. BOILER
• All the coal is fed to the RC feeder from RC bunker
where the coal comes from the coal handling plant
whose size is -20mm. then this coal goes to the mill
for further crushing.
• There are two types of mill is used
1. bowl mill (1,2,5 unit)
2. ball mill (3,4 unit)
• In Stage-I 4 mills are used which feed 4 elevations
out of 6 which run simultaneously.
• The mills employed in Stage-I are Bowl type mills
The coal falls on to the mill grinding table and is
carried under the grinding rolls which reduce the
coal into pulverised form or talcum powdered coal.
Here the size of the coal reaches upto 20µm.
Ques. Why pulverised coal is used?
Ans. The advantages of using pulverised coal are
that it is easily combustible and pulverisation
increases the surface area for combustion and hence
the thermal efficiency increases.
• From the mills the pulverised coal is then taken to
the furnace by the medium of air which is supplied
by the Primary air fan.
There are 2 types of primary fan
1. Hot air type:-Removes the moisture from the
pulverised coal
2. Cold air type:- Used for carrying the coal.

13. • The pulverised coal finally reaches the furnace. It is
a primary part of the boiler where the chemical
energy available in the fuel is converted into
thermal energy by combustion. Furnace is
designed for efficient and complete combustion.
• The pressure inside the furnace is maintained at -
5mm to 10mm of water column. The air inside the
furnace is not sufficient for full coal burning hence
Forced Draught fans are employed for blasting air
inside the furnace at very high pressure.
The method which has been adapted at NTPC UCR is the
Tangential Firing of Corner Firing. Here the burners
are set at each corner of the furnace and directed to strike
the outside of an imaginary circle in the furnace which is
called the Fire Ball. Since the streams of fuel strike each
other, extremely good mixing is obtained.
The following factors in efficient combustion are usually
referred to as “The three T’S”.
a)TIME: It will take a definite time to heat the fuel to
its ignition temperature and having ignited, it will also
take time to burn.
b)TEMPERATURE: A fuel will not burn until it has
reached its ignition temperature. Preheating the
combustion air increases the speed at which this
temperature will be reached.

14. c) TURBULENCE: Turbulence is introduced to
achieve a rapid relative motion between the air and the
fuel particles. This produces a quick propagation of the
flame and its rapid spread throughout the fuel/air mixture
in the combustion chamber.
• The boiler used at FGUTPP is the water tube boiler
type in which, water circulates in tubes surrounded
by fire. Hence it takes up heat and gets converted
into steam.
• The steam then rises up and gets collected inside the
boiler drum which is made up of carbon steel.
• Once the steam is produced in the boiler, it gets
collected inside the boiler drum.
• Boiler drum is a special type of cylindrical drum
like structure which contains a mixture of water and
steam.
• Steam being lighter gets collected at the top portion
and beneath it we have the water.

15. • It is very important to maintain a safe level of water
in the drum since we have two main types of
constraints in this regard. If the steam produced and
collected is more then it can lead to a blast in the
boiler drum else tiny droplets of water can enter the
turbine
• Hence in order to keep a check we measure the level
by hydrastep.
• Hydrastep is a phenomenon based on the difference
in the conductivities of water and steam
• The temperature of steam that comes out of the
boiler is around 350 deg Celsius and its pressure is
147kg/cm2
.
• Since coal is burning in the furnace and then we
have water tubes of the boiler inside hence constant
burning of coal produces ash which gets collected
on the water tubes and the start working as
insulation, hence its necessary to blow this soot
hence for this purpose we use Soot Blowers.
• Soot blowers are basically pipe like structures that
go inside the furnace and the boiler for efficient
onload cleaning. Cleaning is done by the
superheated steam which is tapped from the
superheater for the purpose of soot blowing.
• We mainly have 2 types of soot blowers:
1. long retraceable soot blower (present in both
passes)
2. wall blower (present in 2 pass)
• Before sending this steam to the turbine, the steam
is again superheated and then its temperature is
around 540deg Celsius. This increases the
efficiency. Hence, during the phenomenon of
superheating the steam which is dry and saturated,

16. is being heated and hence the temperature of steam
again rises.
• First the steam from boiler drum enters the LOW
TEMPRATURE SUPER HEATER (LTSH).
• After LTSH steam enters the platen superheater and
then finally to a high temperature superheater. The
steam which is now produced goes to the HP
turbine.
• The type of boiler can be further elaborated as
natural circulation, dry bottom, and tangential
fired, radiant heat type with direct fired
pulverised coal system

17. COMPONENTS OF BOILER
 Boiler Drum: -The function of steam drum is to
separate the water from the steam generated in the
furnace walls and to reduce the dissolved solid
contentsof the steam.The drum is located on the
upper front of boiler.
 Economiser: - The purpose of economizeris to
preheatthe boiler feed water before it is introduced
into the steam drum by recovering heat from the flue
gases leaving the boiler. The Economiseris located in
the boiler rear gas pass below the rear horizontal
superheater.The economizeris continuousunpinned
loop type and water flows in upward direction and
gas in the downward direction.

18.  Superheater: -Steam from the boiler reachesto the
superheater.Outlet temperature and pressure of the
steam coming out from the superheaterare 540°C and
147 Kg/Cm2 From superheaterthe steam reachesto the
HP Turbine.
 Burners: -There are total twenty-four coal burners
pulverized for corner fired boilers and twelve oil
burners. The pulverized coal burners are arranged in
such a way that six mills Supply the coal to the
burners at 4 corners, of the furnace. All the nozzles of
the burners are inter Linked and can be tilted as a
single unit from +30° to -30°.The oil burners are fed
with heavy fuel oil till boiler load reaches to about
25%.

19.  Soot Blowers:-Following three types of soot blowers,
in requisite numbers, are provided:
i. Long retractable soot blowers
ii. Wall blower
Superheatedsteam is tapped from superheaterfor the
purpose of soot blowing.
The pressure is reduced to 31 Kg/cm2 at 330 ºC by means
of pressure reducing valve. The soot blowers are used for
efficienton-load cleaning of furnace, super heaters,
Reheaterand regenerative air heaters.
 P.A. Fan:-The primary air fans (2 per unit - 50%
capacity each) are designed for handling atmospheric

20. air up to a temperature of50 ºC. These fans are
located at ‘0’M level near the boiler.
 Air Pre-heater:-Air pre-heatertransfers heat from
flue gases to cold primary and/ or secondary air by
meansof rotating heating surface elements.Beneath
these regenerative type air pre-heaters, there exists a
steam coil air pre-heater.These are locatedin the
secondary pass of the furnace at a height of around
‘16’ M level. Each 200 MW unit is provided with two
such airpreheaters.
 F.D. Fan: -The forced draft fans (2 per unit - 50%
capacity each) are designed for handling secondary
air for the boiler. These fans are locatedat '0' M level
near the PA Fan.
 Electrostatic Precipitator: -These are generally two
plate type located between boiler and the chimney. The
precipitator is arranged for horizontal gas flow and is
constructed with welded steel casings. It consists of 2
transformer80kv.Its efficiency is 99.99%.
 ID Fans: - There are two induced draft fans per boiler
located between the Electrostatic precipitator and the

21. chimney. Thesefans are used for sucking flue gas from
furnace.
 Chimney: -Theseare tall RCC structures with
single/multiple flues (one flue per 200 MW Unit). The
heights of these chimneys vary depending on the location
considerations; anywhere between 150 m. to 250 m.
TURBINE

22. STEAM CYCLE
Layout of turbine

23. • The superheatedsteam after coming out of the
superheatergoes to the HP turbine.
• After expanding in HP Turbine steam reachesto the
Reheaterthrough cold reheater(CRH).
• From reheaterit reachesto the IP Turbine through
hot reheater(HRH).
• The steam finally reachesto the LP turbine and the
condensed in the condenser.
• Condensate extracting pump (CEP) extract the water
from the condenserand supply it to the LP heaters,
deaerators, BFP and HP heaters.
• From the HP heater6 the water reachesto the
economiser(Boiler).
• In the below table temp. and pressure is given
S.No. Extraction Pressure
(bar)
Temperature
(Celsius)
1. LPH 1 0.425 77
2. LPH 2 0.88 109
3. LPH 3 2.34 198
4. D/A 16.01 427
5. HPH 5 16.01 427
6. HPH 6 38.44 346
STAGES OF TURBINE
• HIGH PRESSURE TURBINE (HPT): - It is a single
flow turbine consists of 25 stages
• HPT

24. • INTERMEDIATE PRESSURE TURBINE (IPT):-It is a
double flow consist of 2*20 stages
• LOW PRESSURE TURBINE (LPT):-It is a double
flow consist of 2*8stages
• SPECIFICVOLUME INCERESES IN EVERY TURBINE
THEREFORESIZE OF TURBINEINCRESES.
(LPT>IPT>HPT)
TURBINE AUXILLARIES
LPT
IPT
M.S
CRH
HRH
LPT
IPT
CONDENSER CONDENSER

25. • CONDENSOR
• COOLING TOWER
• CONDENSATE EXTRACTION
PUMP (CEP)
• LOW PRESSURE HEATERS (LPH)
• DEAERATOR
• BOILER FEED PUMP (BFP)
• HIGH PRESSURE HEATERS
(HPH)
• REHEATERS

26.  Reheater: - The function of Reheateris to reheatthe
steam coming out from HP turbine to a temperature
of 540°C. It is locatedin the paint house.
 Condenser: - A condenseris a commonly used
term for a water-cooled shell and tube heat
exchanger installed on the exhaust steam from a
steam turbine from the thermalpower station it’s a
heat exchanger which convert steam from its gaseous
to its liquid state at a pressure below atmospheric
pressure.
Condensate Extraction Pump: -The function of
Condensate extraction pumps is to pump out the
condensateto the deaerator through gland steam

27. cooler, and LP heaters. The steam from the LP
cylinders’ exhausts into the condensershells where it is
constrainedto flow across the water tubes, through
which cooling water is circulated. The steam condensed
on the tubes drain to the bottom of the shell. The
condensateis retained in the condensershell bottom by
meansof the condenserlevel control valve. The water
in a condenserprovides a head of water for the
condensateextraction pump to suppress cavitation’s in
its suction impellers.
Cooling Tower :-It removesheatfrom the water
discharged from the condenserso that the water can be
discharged to the river or re circulate or re used.
HEATEXCHANGERINTHERMALPOWERPLANT

28.  FEEDWATER HEATER A feed water heateris a
special form of a shell and tube heatexchanger
designed for the application of recovering the heatfrom
the turbine extraction steam by preheatingthe boiler
feed water.
Basically there are two types of heat exchanger are used
in thermalpower plant.
• SHELL AND TUBE HEAT EXCHANGER
o Low pressure heater
o High pressure heater
• DIRECT TYPE HEAT EXCHANGER
o Deaerator
 LOW PRESSURE HEATERS: -Low-pressure feed
water heaters are located upstream from the condensate
pump, which’s takes its suction from the condenserhot
well. Typically, low pressure feed water heatersare
designed for feed water pressures between 27 kg/cm sq.
and 57 kg/cm sq. It bleededthe steam from the stages of
low pressure turbine as
LPH 1 from 7th stage of LP Turbine
LPH 2 from 5th stage of LP Turbine
LPH 3 from 3rd stage of LP Turbine
 HIGH PRESSURE HEATERS
Feed water heatersmay be definedas high-pressure
heaterswhen they are located in the feed water
circuit upstream from the high pressure feed water
pump. ., high pressure feed water heatersrange from

29. 112 kg/cm sq. to 335 kg/cm sq. for super critical
boilers.
It also bleeded steam from different stages
HPH 5 from 11th stage of IP Turbine
HPH 6 from CRH
 Deaerator
• It serves as a feedwater heater.
• Feedwater is deaerated by the removal of non-
condensable gases present in the feedwater and
reduce the oxygen content to a level of about
0.007 ppm.
• It acts as a ‘buffer’ to the fluctuations of
condensate feedwater flow that occur in service
durations.
• The tank height provides a hydrostatic head to
satisfy the suction pressure requirements of the
boiler feed pumps.
The presence of non-condensable gases in the
feedwater causes the waterside corrosion or
thinning of the boiler tube walls and this further
leads to the rupture of walls by the internal fluid
pressure. So for the removal of oxygen from boiler
feed-water and other non-condensable gases
deaerator is used and the process is known as
DEAERATION .

30. It bled steam from three stages:-
1. FROM 11TH STAGE OF IP TURBINE
2. FROM CRH
3. FROM APDRS
 Boiler Feed Pumps:-Boiler feed pumpsare an
importantpart of boiler operation.They control the
amountof water fed to the boiler and the mannerin
which it is fed.
• NET POSITIVE SUCTION HEAD:-The
minimum absolutepressure at the suction nozzle
at which the pump can operate. To avoid pump
cavitations, the NPSHA of the system must be
greater than the NPSHR of the pump.In other
words, the available NPSH must be higher than
the required. We have always sized our deaerator
stands to be two feethigher than the NPSH
neededfor the pump selection. Remember,the
water level in the storage tank adds to the safety
margin.
• BOOSTER PUMP:- Each boiler feed pump is
provided with a booster pump in its suction line
which is driven by the main motor of the boiler
feed pump. One of the majordamageswhich may
occur to a boiler feed pump is from cavitation or
vapour bounding at the pump suction due to
suction failure. Cavitation will occur when the
suction pressure at the pump suction is equal or
very near to the vapour pressure of the liquid to be
pumpedat a particular feed water temperature.
Therefore all the three feed pumps are provided
with a main shaft driven booster suction line for

31. obtaining a definite positive suction pressure. The
boiler feed pump is coupled with its driving motor
through hydraulic coupling
• HYDRAULIC COUPLING:-The hydraulic
coupling serves the purpose of controlling the
speed of feed pump for maintaining a definite
delivery head and delivered quantity of the
feed water as per the requirement of the boiler.

32. By-pass systems:
The by-pass system performs an important function.
It permits the boiler to be operatedindependently of
the turbine-generatorsystem. The by-pass system
comprisestwo main units-
 HP BY-PASS SYSTEM
 LP BY-PASS SYSTEM
HP By-pass system:- This system comprisesof the
operation of bypassing the HP steam without being
passed through the HP turbine. The HP steam is taken
from each of the main steam lines after the HP steam stop
valves. The main steam passes into the cold reheatinlet
pipes via four pressure control valves and their associated
isolating valves. The valve include the spray water
supply and control equipment.The H.P. valve will
operate automatically to maintain upstream pressure on
start .In addition upon rapid load rejection .These valves

33. will operate to relieve 60% of MCR rated steam flow to
the reheatsystem .The H>P>relive valve mountedon the
main steam pipe work will operate to relive excess steam
to atmosphere
LP By-pass system:- The LP by-pass system consists of
four lines taken from the four hot reheat pipes (upstream
of the IP turbine control valves). These four lines are then
converged into two. The steams in each line flows through
an isolating valve, a pressure control valve and then into
the condenserdump tube, bypassing the IP, LP turbines
Turbine gland sealing system:-
HP Turbine, IP-Turbine and LP-Turbine gland leak off are
connectedto seal steam headerand vapour exhauster
system. Initially gland steam requirementfor all the three
cylinders is metby supplying auxiliary steam to the seal
steam headerand the headerpressure is maintainedby
the seal steam control valve. When the unit load is raised
above 30 to 35% HP & IP-glands start supplying gland
leak off steam to the header to the requirementof LP-
glands. Beyond 40% load, no auxiliary steam is required.
Once the self sealing steam takes place, then seal steam
headerpressure is maintainedby opening the leak of
steam control valve to the condenser.

34.  EJECTORS :-Ejectorsare used to create the initial
vacuum in the condenserand maintain a vacuum of
28-29Hg for optimum steam evaporation and also to
extract air and other non condensinggases from
sealed condenser.
They create vacuum upto 98%
TYPES OF VALVES
• Stop valves:- The stop valves are emergency valves
placed in the steam chestsand are provided in the
main steam line. The purpose of the emergency stop
valves is to cut off the steam supply during periods
of shutdown and to provide prompt interruption of
steam flow through the turbine cylinders in an
emergency trip.Normally, these valves are kept open
fully but during emergenciesthese valves are fully
closed (100%). During such conditions,the plant is
producing no power because no input is given to the
turbine.
• Controlling valves:- The governing valves are also
situated in the steam chests. These are the control
valves i.e. they provide accurate control of the steam
flow rate into the turbine, thus controlling the
generator load when the machine is synchronized to
the grid. HP governing valves are the most important
valves. They controls the amountof power produced
by the plant or unit. For a unit producing 500 MW
power, the HP governing valve opening is kept as 40-
45% of the total valve opening.

35.  OIL SUPPLY SYSTEM:-The oil supply system
fulfills the following functions:
a) Lubricating and cooling the bearings.
b) Driving the hydraulic turning gear during
interruptions to operation,on start up and shut down
[1].
Jacking up the shaft at low speeds (turning gear operation,
start up and shut down)
• Lube oil system of turbine consist 4 pumps:-
1. AOP (auxiliary oil pump) - upto 540 rpm
2. EOP (emergency oil pump) - back up of AOP
3. JOP (jacking oil pump) - upto 510 rpm
4. MOP (main oil pump) - more than 2850 rpm
These four pumpsare installedat MOT (MAIN OILTANK)

36. • In thermal power plant bearings have the critical
function of supporting the main engine rotor the
length and the weight are directly affectedby the type
of compressor used in the engine.
• There are two typesofbearing usedin the turbine that
are journal bearing and the thrust cum journal
bearing.
• Where the Thrust cum journal bearing is an anti
friction bearing and it can take axial load where as
journalbearing has the simplest bearing friction and it
can take radial load.

37. ASH HANDLING PLANT
The ash produced in the boiler is transported to the ash
dump area by means of ash handling system. It contains
bottom ash system, fly ash system and ash slurry system.
Bottom Ash-: The bottom ash is collectedin water troughs
employed below bottom ash hoppers. The ash is
continuously transported onto the respective clinker
grinders which reduce lump sizes to fineness.The crushed
ash from the clinker grinder falls into the hopperand from
here it is taken to the ash slurry house.
Fly Ash-: The fly ash also gets collected into the separate
hoppers where it gets mixed with flushing water.
Ash Slurry System-: This is the main system which is
responsible for carrying away the ash slurry.
The bottom ash and the fly ash slurry of the system is
sluiced upto ash slurry pump along the channel with the
aid of high pressure water jets located at suitable intervals
along the channel. The ash slurry pump house has the
following specifications. It contains 4 series with 3 pumps
each to carry water upto 6 kilometres. It has got a control
room where all the controlling is done and simultaneously
monitoringis also there.The panelconsistofvarious relays,
SF6 circuit breaker and other motor controls. These pumps
are all high tension pumps working on 6.6KV. To maintain
the pressure we also have lp seal pump and hp seal pump
which are all driven by 3Φ induction motors
Conclusion

38. On completionof my vocational training at Feroze Gandhi
UnchaharThermal Power Project,Unchahar I have come
to know about how the very necessity of our lives
nowadays i.e., electricity is generated. What all processes
are neededto generate and run the plant on a 24x7 basis.
NTPC Unchahar is one the plants in India to be under
highest load factor for the maximum duration of time and
that to operating at highest plant efficiencies.This plant is
an example in terms of working efficiency and
managementof resourcesto all other thermalplants in
our country. The operating plf of the NTPC as compared
to the rest of country is the highest with 87.54% the
highest since its inception.The training gave me an
opportunity to clear my conceptsfrom practical point of
view with the availability of machinery of such large
rating.