A summer training report by Instrumentation Engineering on a thermal power plant.

1. A SUMMER TRAINING
REPORT
By,
Sayan Bar (EIE/15/12),
Supriya Gorai (EIE/15/01),
Department of Applied Electronics and Instrumentation Engineering,
College of Engineering and Management, Kolaghat
Purba Medinipur

2. The summer training opportunity we had with DPL was a great chance
for learning and professional development. Therefore we consider
ourselves as very lucky individuals as we were provided with an
opportunity to be a part of it.
It is a pleasure to be indebted to various people, who directly or
indirectly contributed in the development of this work and who
influenced our thinking, behaviour and acts during the course of
training and we owe our sincere gratitude and thanks to each and
every people of DPL.
Date:
Signature:

4.  Introduction
 Waterworks,DPPS, DPL
 ThermalPower Plant
o Introduction
o History
o Working ofthermal powerplant
 Energy absorption from steam
 Use of condenser
 Pump
 Heat addition in boiler& Rankine cycle
 Condenserheatrejection – cooling tower
 Boiler furnace for heataddition
o Typical view of thermal powerplant
o Accessories ofthermal powerplant
 Feed water heating and deaeration
 Boiler operation
 Boiler furnace and steam drum
 Superheater
 Steam condensing
 Reheater
 Steam turbine generator
 Stack gas path and clean up
 Bottom ash collection and disposal
 Different types of fan for boileruse
 DPL source watch
 Boiler mountings
o Water level indicator
o Pressure gauge
o Safety valves
o Stem stop valve
o Blow off cock
o Fusible plug
o Feed check valve
 Conclusion

5. The DurgapurProjects Limited is a governmentcompanyincorporated on 6th September
1961, consisting of Coke Oven Batteries, by product plants, Gas Grid Project, Thermal
Power Plant and Water Works. It is underthe administrative control of the departmentof
the power, GovernmentofWestBengal.
The DPL is the first undertaking of the state Governmentwhich has been engaged in the
developmentofthe infrastructure for industries and was given the structure ofan ‘Industry
for Industries’. It has helped in the developmentof various large,medium and smallscale
industries in and around Durgapur and also other places within the state.
DPL today is a renovated and upgraded powerutility. A total of seven units of different
capacities have an aggregate 701MW of installed capacity out of which 2X30 MW units
have been decommissioned reducingthe aggregate installed capacity of 641 MW. After
fulfilling total requirementofits command areacustomers,DPL surplus powergoes to the
West Bengal State Electricity Distribution Company Ltd (WBSEDCL).
ACTIVITIES:
1. Generation of powerand its distribution an 11KV in its licensed area at Durgapur
and transmission ofsurplus power to WBSEB.
2. Production of metallurgical coke of blast furnace, foundries, etc. Coke Oven gas
as industrial fuel and crude oil tar available from its recovery type of coke oven
batteries.
3. Treatment and distribution of water for drinking and industrial use.

6. Water, a major constituent of earth, covering nearly 71% of it is an essential part of living
for all living beingsonearth. Butnot all ofthat consideredasdrinkingwateras water which
can be used for drinking purpose must not contain any impurities or whatsoever. The
drinking water is hardly available in nature and with the advancement of technology
humanshavedevelopedtheir own technologyto purify water from various naturalsources
and make itfavourable for drinking.
In DPL water is taken from Damodar River and is treated for both drinking and industrial
use.DPL has a net capacity of treating 56 MGD (million gallons perday) water and a net
filtering capacity of 40 MGD serving both the purpose of process water for DM plant of
DPPS, DPL and drinking water for neighbourhood.
The water treatment plant of DPPS, DPL has four pump houses on the banks of river
Damodar for the intake ofraw water.
Pump house 1 and 2 are relatively
small with 12 pumps each and a
pump capacity of 1.3 MGD each.
Pump house 3 and 4 have 3 pumps
each, larger in size with net flow of
1500 m3 per house per pump.
DPL uses alum polyelectrolyte and lime for coagulation and pH control and chlorine as a
disinfectant. It has six large clarifier tanks with a capacity of 60ft diameter, 65ft diameter,
130ft diameter, 172ft diameter, 44m diameter, 31.5m diameter and a gravity settling tank
of 100ft diameter. It has also 5 accelerator or settling tank and 3 filter houses with a
capacity of 6 MGD, 8 MGD and 27 MGD respectively.

7. Introduction:Athermal powerstation is a powerstation in which heatenergyis
converted to electric energy.In mostofthe places in the world the turbine is steam driven.
Water is heated, turns into steam and spins a steam turbine which drives an electrical
generator.After it passes through the turbine,the steam is condensedin a condenserand
recycled to where it was heated;this is known as Rankine Cycle.The greatestvariation in
the design of thermal power stations is due to the different heat sources; fossil fuel
dominateshere,althoughnuclearheatenergyandsolarheatenergyare also used.Some
prefer to use the term energycentre because such facilities convert forms of heatenergy
into electrical energy. Certain thermal power stations also are designed to produce heat
energy for industrial purposes,or district heating, or desalination of water, in addition to
generating electrical power.

8. History: The initially developed reciprocating steam engine has been used to
producemechanicalpowersince the 18th century, with notable improvementsbeing made
by James Watt. When the first commercially developed central electrical power stations
were established in 1882 at Pearl Street Station in New York and Holborn Viaductpower
station in London, reciprocating steam engines were used. The developmentof steam
turbine in 1884 provided largerand more efficient machine designs forcentral generating
stations. By 1892the turbines were consideredabetter alternative to reciprocatingengine
turbines offered higher speeds, more compactmachinery, and stable speed regulation
allowing for parallel synchronous operation of generators on a common bus. After about
1905, turbines entirely replaced reciprocating engines in large central power stations.
The largestreciprocating engine generatorsets ever built were completed in 1901 for the
Manhattan Elevated Railway. Each of 17 units weighed about 500 tons and was rated
6000 KW; a contemporary turbine set of similar rating would be weighed about 20% as
much.

9. Working of Thermal Power Plant:Thermalpowerplants use
water as working fluid. Nuclearand coalbased power plants fall underthis category. The
way energy gets transformed into electricity forms the working of a power plant. In a
thermal power plant a steam turbine is rotated with the help of high pressure and high
temperature steam and this rotation is transferred to a generator to produce electricity.
1.ENERGY ABSORPTION FROM STEAM: When steam blades get
rotated by high pressure high temperature steam,the steam loses its energy.This in
turn result in a low pressure and low temperature steam at the outlet of the turbine.
Heresteam is expandedtill saturation pointis reached.Since thereis noheataddition
or removal from the steam, ideally entropy of the steam remains same.This change
is depicted in the following p-v and t-s diagrams. If we can bring this low pressure,

10. low temperature steam back to its original state, then we can produce electricity
continuously.
2.USE OF CONDENSER: Compressing a fluid which is in a gaseous state
required a huge amount of energy, so before compressing the fluid it should be
converted into liquid state. A condenseris used for this purpose,which rejects heat
to the surrounding and converts steam into liquid. Ideally there will not be any
pressure change during this heat rejection process,since the fluid is free to expand
in a condenser. Changes in the liquid are shown in the p-v and t-s diagram below:
3.PUMP: At the exit of the condenserthe fluid is in liquid form, so we can use a
pump to raise the pressure. During this process the volume and temperature (2-3

11. deg.C rise) of fluid hardly changes, since it is in liquid state. Now the fluid has
regained its original pressure.
4.HEAT ADDITION IN BOILER AND RANKINE CYCLE: Here
external heat is added to the fluid in order to bring the fluid back to its original
temperature. This heatis added through a heatexchangercalled the boiler.Here the
pressure of the fluid remains the same, since it is free to expand in heat exchanger
tubes. Temperature rises and liquid gets transformed to vapour and regains its
original temperature. This completes the thermodynamic cycle at a thermal power

12. plant, called Rankine Cycle. This cycle can be repeated and continuous power
production is possible.
5.CONDENSER HEAT REJECTION – COOLING TOWER: In order
to reject heat from the condenser a colder liquid should make contact with it. In a
thermal power plant continuous supply of cold water is produced with the help of a
cooling tower.
6.BOILER FURNACE FOR HEAT ADDITION:Heatis addedto the boiler
with the help of a boiler furnace. Here fuel reacts with air and produces heat. In a
thermal power plant, the fuel can be either coal or nuclear. When coal is used as a
fuel its produces a lot of pollutants which have to be removed before ejecting to the
surrounding.This is done using a series of steps, the most important of them is an
electrostatic precipitator (ESP) which removes ash particles from the exhaust. Now
much cleaner exhaust is ejected into the atmosphere via a stack.

13. Typical View of Thermal Power Plant:
1. Cooling tower 2. Cooling water pump
3. Transmission line (3-phase) 4. Step-up transformer (3-phase)
5. Electrical generator(3-phase) 6. Lowpressure steam turbine
7. Condensate pump 8. Surface condenser
9. Intermediate pressure steam turbine 10. Steam control valve
11. High pressure steam turbine 12. Deaerator
13. Feedwaterheater 14. Coalconveyor
15. Coalhopper 16. Coalpulverizer
17. Boiler steam drum 18. Bottom ash hopper
19. Superheater 20. Forced draftfan
21. Reheater 22. Combustion air intake
23. Economizer 24. Air preheater
25. Precipitator 26. Induced draft fan
27. Flue gas stack

14. Accessories of Thermal Power Plant:In the nuclear plant
field, steam generators refers to a specific type of large heat exchanger used in a
pressurized water reactor (PWR) to thermally connect the primary (reactor plant) and
secondary(steam plant) systems, which generates steam. In a nuclear reactor called a
boiling water reactor (BWR), water is boiled to generate steam directly in the reactor itself
and there are no units called steam generators.
In some industrial settings, there can also be steam producing heat exchangers called
heatrecovery steam generators (HRSG) which utilize heatfrom some industrial process,
mostcommonly utilizing hotexhaustfrom a gas turbine. The steam generating boilerhas
to produce steam at high purity, pressure and temperature required for the steam turbine
that drives the electrical generator.
Geothermal plants do not need boilers because they use naturally occurring steam
resources.Heatexchangermaybe used where the geothermalsteam is very corrosive or
contains excessive suspended solids.
1.Feedwater Heating and Deaeration: The boiler
feedwater used in the steam boileris a means oftransferring heatenergy from the
burning fuel to the mechanicalenergyofthe spinning steam turbine. The total feed
water consists of recirculated condensate feedwater and purified makeup water.
Because the metallic materials it contacts are subject to corrosion at high
temperatures and pressures, the makeup water is highly purified before use. A
system of water softeners and ion exchange demineralizers produces water so
pure that it coincidentally becomes an electrical insulator. The makeup water in a
500 MW plantamounts to perhaps 120 US gallons perminute (7.6 L/s) to replace
water drawn off from the boiler drum for water purity management, and to also
offset the small losses from steam leaks in the system.

15. 2.Boiler operation: The boiler is a rectangularfurnace about50ft on a
side and 130ft tall. It walls are made of a web of high pressure steel tubes about
2.3 inches in diameter. Pulverized coal is air-blown into the furnace from burners
located atthe four corners,or alongonewall, or two opposite walls, andit is ignited
to rapidly burn, forming a large fire ball at the centre. The thermal radiation of the
fireball heats the water that circulates through the boiler tubes near the boiler
perimeter. The water circulation rate in the boiler is three to four times the
throughput. As the water in the boiler circulates it absorbs heatand changes into
steam. It is separated from the water in a drum at the top of the furnace. The
saturated steam is introducedinto superheatpendenttubesthat hangin the hottest
part of the combustion gases as they exit the furnace. Here the steam is
superheated to 1000 oF to prepare itfor the turbine.
3.Boiler Furnace and Steam Drum: The water enters the
boiler through a section in the convection called the economizer. From the
economizer it passes to the steam drum and from there it goes through
downcomers to inlet headers at the bottom of the water walls. From the headers
the water rises through the water walls ofthe furnace wheresome ofit is tuned into

16. steam and the mixture ofwater and steam re-enters the steam drum.This process
may be driven purely by natural circulation or assisted by pumps. In the steam
drum, water is returned to the downcomers and the steam is passed through a
series of steam separators and dryers that remove water droplets from the steam.
The dry steam then flows into the superheater coils.
4.Superheater:Fossilfuel powerstations often have asuperheatersection
in the steam generating furnace. The steam passes through drying equipment
inside the steam drum on to the superheater, a set of tubes in the furnace. Here
the steam picks up more energy from hot flue gases outside the tubing, and its
temperature is now superheated above the saturation temperature. The
superheatedsteamis then pipedthroughthe main steam lines to the valves before
the high pressure turbine.

17. 5.Steam Condensing:The condensercondenses the steam from the
exhaustof the turbine into the liquid to allow it to be pumped.If the condensercan
be madecooler,the pressureofthe exhauststeam is reducedandefficiency of the
cycle increases.
6.Reheater: Power station furnaces may have a reheatersection containing
tubes heated by hot flue gases outside the tubes. Exhaust steam from the high
pressureturbineis passedthroughtheseheatedtube to collectmoreenergybefore
driving the intermediate and then low pressure turbines.
7.Steam Turbine Generator: The turbine generatorconsists of
a series of steam turbines interconnected to each other and a generator on a
common shaft. There is usually a high-pressureturbine and at one end, followed
by an intermediate-pressure turbine, and finally one, two, or three low-pressure
turbines, and the generator. As steam moves through the system and loses
pressure and thermal energy, it expands in volume, requiring increasing diameter
and longerblades at each succeeding stage to extract the remaining energy. The
entire rotating mass may be over 200 metric tons and 100 feet long.It is so heavy
that it must be kept turning slowly even when shut down so that the shaft will not

18. bow even slightly and become unbalanced.This is so important that it is one of
only six functions of blackoutemergency power batteries on site.
8.Stack Gas Path and Clean Up: As the combustion flue gas
exits the boiler it is routed through a rotating flat basketof metal mesh with picks
up heatand returns itto incoming fresh air as the basketrotates. This is called the
air preheater. The gas exiting the boiler is laden with fly ash, which are tiny
spherical ash particles. The flue gas contains nitrogen along with combustion
products carbon dioxide, sulphur dioxide and nitrogen oxides. The fly ash is
removed by fabric bag filters in baghouses or electrostatic precipitators. Once
removed, the fly ash by-products can sometimes be used in the manufacturing of
concrete. This cleaning up of flue gases,however, only occurs in plants that are
fitted with the appropriate technology.Still, the majority of coal-fired powerstations
in the world do not have this facilities. China is now beginning to grapple with the
pollution caused by coal-fired power stations.
9.Fly Ash Collection: Fly ash is captured and removed from the flue
gas by electrostatic precipitator fabric bag filters located at the outlet of the furnace
and before the induced draft fan. The fly ash is periodically removed from the
collection hoppers below the precipitators or bag filters. Generally, the fly ash is

19. pneumatically transported to storage silos for subsequenttransport by trucks or
railroad cars.
10. Bottom Ash Collection and Disposal: At the
bottom of the furnace, there is a hopper for the collection of bottom ash. This
hopperis keptfilled with water to quenchthe ash andclinkersfalling downfrom the
furnace. Arrangements re include to crush the clinkers and convey the crushed
clinkers andbottom ash to a storage site. Ash extractors are usedto dischargeash
from municipal solid waste fired boilers.

20. 11. Different types of Fan for Boiler House: A
fan can be defined as a volumetric machine which like pump moves quantities of
air and gas from one place to another.In doing so it overcomes resistance to flow
by supplying the fluid with the energy necessary for contained motion.
a. Forced DraughtFan:To take air from atmosphere atambienttemperature
to supplyessentially all the combustion aircan either be sized to overcome
all the boiler loses or putthe air in furnace.
b. Induced Draught Fan: Used only in balanced draught unit to suck the
gases outof furnace and through them into the stack. Handle fly ash laden
gases attemperature of125-200. Speed seldom exceed 1000 r.p.m.
c. Primary Air Fan: Used for pulverized system usually sized for 1500 r.p.m.
due to high pressure.
d. Ignite Air Fan: Used to provide necessary combustion air to the ignite
control damperis provided on the discharge which modulates to maintain a
constant differential pressure across ignite when any ignite is in service.
Typically speed 1460 r.p.m.
e. Scanner Air Fan: Used to provide necessary cooling air to the flame
scanners. Typically speed 3000 r.p.m.
INDUCED DRAUGHT FAN
RATED POWER 671.4K/W900 HP
REVOLUTION PER MINUTE 740
FREQUENCY(HZ), PHASE 50, 3
RATED VOLTAGE (VOLT) 6600
RATED CURRENT (AMP) 74
RATING MCR
INSULATION GLASS F
DUTY SI, GD (MOTOR)

21. ALT 1000M
AMBIENT TEMPERATURE 50
MANUFACTURED BY CROMPTION GREAVES
FORCED DRAUGHT FAN
RATED CURRENT (AMP) 43
RATED VOLTAGE (VOLT) 6600
RATED POWER, PHASE 375KW/500HP, 3
REVOLUTION PER MINUTE 988
POWER FACTOR 0.8
MANUFACTURED BY BHEL
SPECIFICATION OF ESP
NO OF EMITTER PLATE (-)VE 6*10
NO OF COLLECTER PLATE (+)VE 4*6
NO OF TRANSFORMER 6*1
SL NO 11427A
TYPE OTHA43/80
DC VOLT (KV) 43
CURRENT (AMP), PHASE 8,1
AC I/P VOLTAGE(V), CURRENT (A) 360,157
AC O/P VOLATGE (V), CURRENT (A) 49.45,1.148
RATED VOLATGE AMPS (KVA) 56.77
MANUFACTURED BY HINLAND RECTIFIED LIMITED
BOILER FEED PIMP
RATED POWER (KW) 4000
REVOLUTION PER MINUTE 2986
FREQUENCY (HZ), PAHSE 50, 03
STATOR 66000,400
INSULATION GLASS B
ROTOR SQUIRREL CAGE

22. EFFICIENCY (%) 96.6
POWER FACTOR .914
TOTAL WEIGHT (KG) 22000
MANUFACTURED BY BHEL
ELECTRIC OIL HEATER
TYPE INDIRECT
SERIAL NO 1-84-60-091
NO OF ELEMENTS 80
POWER 60
RATED VOLTAGE (VOLT) 440
PHASE 03
MANUFACTURED BY PENNWALT INDOAT LIMITED

23. Background: The power station is owned by Durgapur Projects Limited, a
governmententerprise ofWestBengal. The plantcomprises the following units:
 Unit 1 - 30 MW - 1960 - retired
 Unit 2 - 30 MW - 1960 - retired
 Unit 3 - 70 MW - 1964 - retired 2017
 Unit 4 - 75 MW - 1964 - retired 2017
 Unit 5 - 75 MW - 1966 - retired 2017
 Unit 6 - 110 MW - 1987
 Unit 7 - 300 MW - 2008
 Unit 8 - 250 MW – 2014
 Expansion: DurgapurProjects Ltd has proposed a 300 MW extension known
as Unit 8, or unit 7a. It was listed as under construction in 2012, and scheduled for
completion in December 2013.
In June 2014 itwas reported thatunit8 would start generation by the nextmonth.
Project Details of Expansion:
Sponsor: DurgapurProjects Limited
Location: Durgapur Village,WestBengal
Coordinates: 23.5211473,87.3023093(exact)
Status: Operating
Capacity: 250 MW

24. Type: Subcritical Projected in service: 2014
CoalType: Bituminous

25. Mountings are required for properand safe functioning of the boiler which are generally
mounted over the boiler shell.
 Water level indicator
 Pressure gauge
 Safety valves
 Steam stop valve
 Blow off cock
 Fusible plug
 Feed check valve
Fitting and devices which are necessary for the safety and control are knows as boiler
mountings.

26.  The water level indicator is neededto ascertain the water level
of a boiler.
 Two water level indicators should be fitted for each boilerin
sucha place thatthe waterlevel canbe constantly seen.
 A pressure gauge is an
instrument by means of which
the pressure exerted inside a
vessel can be measured.
 There aretwo types of pressure
gauges, one is bourdon tube
and the otheris diaphragm type
gauge.

27.  The safety valve (pressure release valve) is used in a
boiler to relieve the pressure ofsteam when it is above
the working pressure.
 Its function is to discharge a portion of the steam from
the boiler automatically when the steam pressure
exceedsthe normallimit. It is mounted on the top ofthe
shell.
 As per boiler regulation two safety valves are required
to be fitted in each boiler.
 The function of the stop valve or
junction valve is to regulate the flow of
steam from the boiler to the main
steam pipe.
 To shutoff the steam completely when
required.

28.  The blow-off cock has two main functions:
o It may empty the boiler when
necessaryforcleaning,inspection
and repair.
o It maydischargeaportion ofwater
when the boiler is in operation to
blow out mud, scale or sediments
periodically.
 It is fitted at the lowestpartofthe boilereither
directly with the boiler shell or to a pipe
connected with the boiler.

29. To extinguish fire in the event of water level in the boiler shell falling below a certain
specified limit. It protects fire tube from burning when the level of water in the water shell
falls abnormally low and the fire tube or the crown plate which is normally submergedin
the water, gets exposed to steam space which may notbe able to keep itcool.
To allow the feed water to pass into the boiler.
To prevent the back flow of water from the boiler in the
event of failure of the feed pump.

31. Thus it can be seen that Durgapur Projects Limited (DPL) is a
multidisciplinary industrial establishment that serves the need of
electricity by generating power through its thermal power plants and
various other auxiliary units. If DPL uses its full capacity it will soon be
one of the industrial foundation to be reckoned with its own sector in
terms of productivity and quality and consumer satisfaction in the near
future as did in the past.
It has been a great experience for us to get acquainted with so many
people associated with this huge project. It has been extremely
knowledgeable for us to learn so many operational process that run in
an industry and to be a part of it and to see that very closely even
though for a short while during the training period.
Thanks a lot for all.
Date:
Signature: