Paras Thermal Power plant Akola Maharashtra

1. Industrial visit Report
On
PaRAS THERMAL POWER PLANT
Akola
2016 - 17
Submitted by
1)Abhijeet Amnerkar 2) Amit Hinge
3)Bhushan khadse 4)Chandanlal Bahetwar
5)Dinesh Dakhore 6)Piyush Bhat

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INDEX
 Abstract
 Introduction
 what is thermal power plant
 Schematic of thermal power plant
 Different elements of power station
 Coal Preparation
 Fans
 Boiler
 Superheater
 Turbine
 Generator
 Condenser
 Cooling Tower
 Boiler Feed Pump
 Ash Handling plant
 Thermal power plant operation
 Conclusion
 Reference

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Acknowledgement
We express our feeling of gratitude to the Chief Engineer (C&O), Paras
Thermal Power Station for granting permission to visit the plant. We are
especially very much thankfultoMr. Hitesh Khapekar AssistantEngineer, who
took great effort to sharehis practicalknowledgetoenhancethetechnicalskill
of the students. We would like to appreciate their concern for the technical
upliftment of the students.
We are very much thankful to Prof. Shailesh Watekar, HOD of Electrical
Department for allowing and guiding for theproper execution of the visit. We
are also very much thankful to the management of Agnihotri college of
Engineering Nagthana Road, Wardha for allowing the visit.

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Abstract
Paras Thermal Power Plant is oldest power plant of Maharashtra
StatePower Generation Company (Mahagenco) located at Paras, Akola district
of Maharashtra. The power plant is one of the coal based power plants of
MahagencoParasThermalPower Station is the oldest of all Mahagenco Power
plants. Thestation has witnessed the third generation technology. The station
had 30 MW installed capacity in 1961 with a strokeboilerAlmost two third of
electricity requirement of the world is fulfilled by thermal power
plants (or thermalpower stations). In these power stations, steam is produced
by burning some fossil fuel (e.g. coal) and then used to run a steam turbine.
Thus, a thermalpower station may sometimes called as a Steam Power Station.
After the steam passes through the steam turbine, it is condensed in a
condenser and again fed back into the boiler to become steam. This is known
as ranking cycle. This article explains how electricity is generated in thermal
power plants. As majority of thermal power plants use coal as their primary
fuel, this article is focused on a coal fired thermal power plant.

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Introduction
About Paras Thermal Power Plant :-
Paras Thermal Power Plant is oldest power plant of Maharashtra State
Power Generation Company (Mahagenco) located at Paras, Akola district
of Maharashtra. The power plant is one of the coal based power plants of
Mahagenco.
Paras ThermalPower Station is the oldest of all Mahagenco plants. The
station has witnessed the third generationtechnology. Thestation had 30 MW
installed capacity Power in 1961 with a stroke boiler. The same unit we
abandoned in 1993 due to ageing.
It is on the Nagpur–Bhusawal section of Central Railway.Coal-based thermal
power stations consume large quantities of coal.[3] For example, the Paras
Thermal Power Station consumed 351,000 tonnes of coal in 2006-07.[4]
Around 80 per cent of the domestic coal supplies in India are meant for coal
based thermalpower plants and coal transportation forms 42 per cent of the
total freight earnings of Indian railways.
Mahagenco's Paras Thermal Power Station located near Akola
completed 50 years in power generation on October 25 and marching
towards overall renovation.
Later, one more unit of 58MW was developed in the power station. Due to
old age of theunits, Mahagencohad replaced theold units with new ones and
both of the units are non-existent today.
Paras TPS has started to witness a fresh life with commissioning of two new
units in last couple of years. Currently, two units each with capacity of
250MW for a total of 500MW have been functioning at the power station,
thus playing a vital role in state's power scenario. Besides, Mahagenco has
proposed to develop one more new unit with capacity of 660MW.

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Whatis Thermal power Plant
A thermal power station is a power plant in which heat energy is
converted to electric power. In most of the 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 condensed in a condenser and recycled to where it
was heated; this is known as a Rankine cycle. The greatest variation in the
design of thermal power stations is due to the different heat sources, fossil
fuel dominates here, although nuclear heat energy and solar heat energy are
also used. Some prefer to use the term energy centre because such facilities
convert forms of heat energy into electrical energy. Certain thermal power
plants also are designed to produce heat energy for industrial purposes
of district heating, or desalination of water, in addition to generating electrical
power.
Types of Thermal Energy
Almost all coal, nuclear, geothermal, solar thermal electric, and waste
incineration plants, as well as many natural gas power plants are
thermal. Naturalgas is frequently combusted in gas turbines as well as boilers.
The waste heat from a gas turbine, in theform of hot exhaust gas, can be used
to raise steam, by passing this gas through a Heat Recovery Steam Generator
(HRSG) the steam is then used to drive a steam turbine in a combined
cycle plant that improves overall efficiency. Power plants burning coal, fuel
oil, or natural gas are often called fossil-fuel power plants. Some biomass-
fueled thermalpower plants haveappeared also. Non-nuclear thermal power
plants, particularly fossil-fueled plants, which do not use co-generation are
sometimes referred to as conventional power plants.

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Commercial electric utility power stations are usually constructed on a large
scale and designed for continuous operation. Virtually allElectric power plants
use three-phase electrical generators to produce alternating current (AC)
electric power at a frequency of 50 Hz or 60 Hz. Large companies or
institutions may have their own power plants to supply heating or electricity
to their facilities, especially if steam is created anyway for other purposes.
Steam-driven power plants have been used to drive most ships in most of the
20th century until recently. Steam power plants are now only used in large
nuclear naval ships. Shipboard power plants usually directly couple the
turbinetotheship's propellers through gearboxes. Power plants in such ships
also provide steam to smaller turbines driving electric generators to supply
electricity. Nuclear marine propulsion is, with few exceptions, used only in
naval vessels. There have been many turbo-electric ships in which a steam-
driven turbine drives an electric generator which powers an electric
motor for propulsion.
Combined heat and power plants (CH&P plants), often called co-generation
plants, produceboth electric power and heat for process heat or space heating.
Steam and hot water.

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Diagram of a typical coal-fired thermal power station

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Thermal Power Plant
At present 54.09% or 93918.38 MW (Data Source CEA, as on
31/03/2011) of total electricity production in India is from Coal Based
Thermal Power Station. A coal based thermal power plant converts the
chemical energy of the coal into electrical energy. This is achieved by raising
the steam in the boilers, expanding it through the turbine and coupling the
turbines to the generators which converts mechanical energy into electrical
energy.
Introductory overview
In a coal based power plant coal is transported from coal mines to the
power plant by railway in wagons or in a merry-go-round system. Coal is
unloaded from thewagons to a moving underground conveyor belt. This coal
from the mines is of no uniform size. So it is taken to the Crusher house and

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crushed toa size of 20mm. From thecrusher house the coal is either stored in
dead storage( generally 40 days coal supply) which serves as coal supply in
case of coal supply bottleneck or to the live storage(8 hourscoal supply) in the
raw coal bunker in the boiler house. Raw coal from the raw coal bunker is
supplied to the Coal Mills by a Raw Coal Feeder. The Coal Mills or pulveriser
pulverizes thecoal to 200 mesh size. The powdered coal from the coal mills is
carried to theboiler in coal pipes by high pressure hot air. The pulverized coal
air mixture is burnt in the boiler in the combustion zone.
Generally in modern boilers tangential firing system is used i.e. the coal
nozzles/ guns form tangent to a circle. The temperature in fire ball is of the
order of 1300 deg.C. The boiler is a water tube boiler hanging from the top.
Water is converted tosteam in theboiler and steam is separated from water in
theboiler Drum. Thesaturated steam fromthe boiler drum is taken to the Low
Temperature Superheater, Platen Superheater and Final Superheater
respectively for superheating. The superheated steam from the final super
heater is taken to theHigh Pressure Steam Turbine (HPT). In theHPT the steam
pressure is utilized to rotatetheturbineand the resultant is rotational energy.
From the HPT the out coming steam is taken to the Reheater in the boiler to
increase its temperature as the steam becomes wet at the HPT outlet. After
reheating this steam is taken to the Intermediate Pressure Turbine (IPT) and
then to the Low Pressure Turbine (LPT). The outlet of the LPT is sent to the
condenser for condensing back to water by a cooling water system. This
condensed water is collected in the Hot well and is again sent to the boiler in a
closed cycle. The rotational energy imparted to the turbine by high pressure
steam is converted to electrical energy in the Generator.

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Principal
Coal based thermalpower plant works on theprincipalof Modified Rankine
Cycle.

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Components of Coal Fired Thermal Power Station:
 Coal Preparation
Fig. Coal Handling Plant
i)Fuel preparation system: In coal-fired power stations, the raw feed coal
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.

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** 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
Types of Pulverisers: Ball and Tube mills; Ring and Ball mills; MPS; Ball mill;
Demolition.
ii)Dryers: they areused in order to remove the excess moisturefrom coal
mainly wetted during transport. As the presence of moisturewill result in fall
in efficiency dueto incomplete combustion and alsoresult in CO emission
iii)Magnetic separators: coal which is broughtmay contain iron particles.
These iron particles may result in wear and tear. The iron particles may
includebolts, nuts wire fish plates etc. so theseare unwanted and so are
removed with the help of magnetic separators.
The coal we finally get after these above process are transferred tothestorage
site.
Purposeof fuel storageis two –
 Fuel storage is insurance from failureof normal operating supplies to
arrive.
 Storagepermits some choiceof thedate of purchase, allowing the
purchasertotakeadvantage of seasonal market conditions. Storageof
coal is primarily a matter of protection againstthecoal strikes, failureof
thetransportation system & general coal shortages.

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 Fan
In a boiler it is essential to supply a controlled amount of air to the furnacefor
Effectivecombustion of fuel and to evacuate hot gases formed in the furnace
throughthevarious 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 fans
When the required flow of air and flue gas through a boiler can be obtained
by thestack (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 theunit 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 tolow pressure
at the top.
ii) Mechanized fans
There are 3 types of mechanized draught systems
1) Forced draught fans
2) Induced draught fans
3) Balanced draught fans

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Forced draught fan: – In this system a fan called Forced draughtfan is installed
at theinlet of the boiler. This fan forces theatmospheric air through the boiler
furnaceand pushes out the hot gases from the furnace through superheater,
reheater, economiser and air heater to stacks.
Fig. FD Fan
Induced draught fan: – 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 thechimney. This results in the furnace pressure lower than atmosphere
and affects the flow of air from outside to the furnace.

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Fig. ID Fan
Primary Draught fan:-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
called balancing point.

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Fig. PA Fan
There are two types of storage:
1. Live Storage (boiler room storage): storage from which coal may be
withdrawn tosupply combustion equipment with littleor 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. Thelive storagecan 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 futureuse. Mainly it is for longer period of time,
and it is also mandatory tokeep 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. Stackingthecoal in heaps over availableopen ground areas.
2. As in (I). But placed under cover or alternatively in bunkers.
3. Allocating special areas & surroundingthesewith high reinforced
concerted retakingwalls.

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Boiler and auxiliaries
Fig. Boiler
A Boiler or steamgenerator 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

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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 towater for evaporation as well to steam for
superheating.
The basic components of Boiler are: -
1. Furnace and Burners
2. Steam and Superheating
a. Low temperature super heater
b. Platen super heater
c. Final super heater
Types Of Boiler
.
Fire-tube Boilers
Fig. Fire tube Boiler
In fire-tubeboilers, combustiongases pass throughtheinsideof thetubes with
water surroundingtheoutsideof the tubes. Theadvantages of a fire-tube
boiler are its simple constructionand less rigid water treatment requirements.

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The disadvantages aretheexcessive weight-per-pound of steamgenerated,
excessive time required to raisesteam pressure becauseof therelatively large
volume of water, and inability to respond quickly toload changes,again, due
to the largewater volume.
The most common fire-tubeboilers used in facility heating applications are
often referred to as ''scotch'' or ''scotch marine'' boilers, as this boiler type was
commonly used for marineservice becauseof its compact size(fire-box
integralwith boiler section)
.
Water tube Boiler
Fig. Water tube Boiler
in a water-tube boiler ('''Figure 3'''), the water is inside the tubes and
combustion gases pass around the outside of the tubes. The advantages of a
water-tubeboiler area lower unit weight-per-pound of steam generated, less

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time required to raise steam pressure, a greater flexibility for responding to
load changes, and a greater ability to operateat high rates of steamgeneration.
A water-tubedesign is the exact opposite of a fire-tube. Here, the water flows
throughthetubes and is encased in a furnacein which theburner fires. These
tubes are connected to a steam drum and a mud drum. The water is heated
and steam is produced in the upper drum.
 Economiser
Fig. Economiser

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It is located below theLPSH in the boiler and above pre heater. It is there to
improve the efficiency of 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 efficiency of boiler
plant.
2) Reducing size of boiler: – as the feed water is preheated in the economiser
and enter boiler tubeat elevated temperature. The heat transfer area required
for evaporation reduced considerably.
 Air Preheater
The heat carried out with the flue gases coming out of economiser are further
utilized for preheating theair beforesupplying to the combustion chamber. It
is a necessary equipment for supply of hot air for drying thecoal in pulverized
fuel systems to facilitate grinding and satisfactory combustion of fuel in the
furnace
 Superheater
Fig. Superheater
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.

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When a steamsystemis designed for superheat,thedesignershould ensure
that thesteamexit thesuperheateris superheated about5.6o
C(10o
C)higherthan
the desired superheat temperature. The steam temperature is not controlled
using bypasses on the superheaters but by desuperheating equipment.
Types of Turbine
 Steam turbines

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Fig. Steam Turbine
Steam turbines have been used predominantly as prime mover in all thermal
power stations. The steam turbines are mainly divided into two groups: -
1. Impulse turbine
2. Impulse-reaction turbine
The turbine generator consists of a series of steam turbines interconnected to
each other and a generator on a common shaft. There is a high pressure
turbine at one end, followed by an intermediate pressure turbine, two low
pressure turbines,and thegenerator. Thesteamat high temperature (536 ‘c to
540 ‘c) and pressure (140 to 170 kg/cm2) is expanded in the turbine.
 Water Turbine

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Fig. Water Turbine
A water turbine is a rotary machine that converts kinetic
energy and potential energy of water into mechanical work.
Water turbines weredeveloped in the19th century and were widely used for
industrialpower prior to electricalgrids. Now they are mostly used for electric
power generation. Water turbines are mostly found in dams to generate
electric power from water kinetic energy.
 Wind Turbine

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Fig. Wind Turbine
A wind turbine is a device that converts thewind's kinetic
energy intoelectricalpower. Wind turbines aremanufactured in a wide
rangeof verticaland horizontalaxis types. The smallest turbines are
used for applications suchas battery chargingfor auxiliary power for
boats or caravans or to power traffic warning signs. Slightly larger
turbines can beused for making contributions toa domestic power
supply while selling unused power back to theutility supplier via
theelectricalgrid. Arrays of large turbines,known as wind farms, are
becoming an increasinglyimportant sourceof intermittent renewable
energy and are used by many countries as part of a strategy toreduce
their relianceon fossil fuels.
 Generator

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Fig. Generator
Generator or Alternator is the electrical end of a turbo-generator set.
It is generally known as the piece of equipment that converts the mechanical
energy of turbineintoelectricity. The generation of electricity is based on the
principle of electromagnetic induction.
In electricity generation, a generator is a device that
converts mechanicalenergy toelectricalenergy for use in an external circuit.
Sources of mechanicalenergy include steamturbines, gas turbines, water
turbines, and internalcombustion engines and even hand cranks. Thefirst
electromagneticgenerator, theFaraday disk, was built in 1831 by British
scientist MichaelFaraday. Generatorsprovide nearly all of thepower
for electric power grids.
The reverseconversion of electricalenergy intomechanicalenergy is done by
an electric motor, and motors and generators havemany similarities. Many
motors can be mechanically driven togenerateelectricity and frequently make
acceptablemanualgenerators.
 Condenser

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Fig. 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 efficiency of
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

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Fig. 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
 Boiler feed pump

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Fig. Boiler Feed pump
Boiler feed pump is a multi stage pump provided for pumping feed
water to economiser. BFP is the biggest auxiliary equipment after Boiler and
Turbine. It consumes about 4 to 5 % of total electricity generation.
Boiler feed water pump is a specific type of pump used to
pump feed water into a steam boiler. The water may be freshly
supplied or returning condensate produced as a result of the
condensation of the steam produced by the boiler. These pumps are
normally high pressure units that take suction from a condensate
return system and can be of the centrifugal pump type or positive
displacement type.
 Ash handling system

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Fig. Ash Handling Plant
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% throughfluegases, so called Fly ash and collected in
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 attracted by charged electrodes. The electrodes are
maintained at 60KV.Hammering is done to the plates so that fly ash comes
down and collect at the bottom. The fly ash is dry form is used in cement
manufacture.

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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

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Thermal Power Plants Operation
Thermal power plants use water as working fluid. Nuclear and coal based
power plants fall under this category. The way energy from fuel gets
transformed intoelectricityforms the working of a power plant. In a thermal
power plant a steam turbine is rotated with help of high pressure and high
temperature steam and this rotation is transferred to a generator to produce
electricity.
Fig.1 Power is produced in thermal power plants by rotating steam turbine
Energy absorption from steam
When turbineblades get rotated by high pressurehigh temperaturesteam, the
steam loses its energy. This in turn will result in a low pressure and low
temperature steam at the outlet of the turbine. Here steam is expanded till
saturationpoint is reached. Sincethereis no heat addition 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, low
temperature steam back to its original state, then we can produce electricity
continuously.

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Fig.2 Pressure and temperature drop of steam when turbine absorbs energy from it
Use of Condenser
Compressing a fluid which is in gaseous state requires a huge amount of
energy,sobefore compressing thefluid it should be converted into liquid state.
A condenser is 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 fluid are shown in the p-v and T-s diagram below.
Fig.3 Use of condenser in order to transform vapor into liquid state

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Pump
At exit of the condenser fluid is in liquid state, so we can use a pump to raise
the pressure.During this process the volume and temperature (2-3 deg.C
rise)of fluid hardly changes, since it is in liquid state. Now the fluid has
regained its original pressure.
Fig.4 Compressor pumps the fluid to its original pressure
Heat Addition in Boiler & Rankine Cycle
Here external heat is added to the fluid in order to bring fluid back to its
original temperature. This heat is added through a heat exchanger called a
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 tovapor and regains its original temperature. This completes the
thermodynamic cycle of a thermal power plant, called Rankine Cycle. This
cycle can be repeated and continuous power production is possible.

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Fig.5 Heat addition at boiler brings the fluid to its original temperature
Condenser Heat Rejection - Cooling Tower
In order to reject heat from the condenser a colder liquid should make contact
with it. In a thermalpower plant continuous supply of cold liquid is produced
with the help of a cooling tower. Cold fluid from the cooling tower absorbs
heat from a condenser and gets heated, this heat is rejected to the atmosphere
via natural convection with the help of a cooling tower.
Boiler furnace for Heat Addition
Heat is added to the boiler with help of a boiler furnace. Here fuel reacts with
air and produces heat. In a thermalpower plant, the fuel can be either coal or
nuclear. When coalis used as a fuelit produces a lot of pollutants which have
to be removed beforeejecting to the surroundings. This is done using a series
of steps, the most important of them is an electro static precipitator (ESP)
which removes ash particles from the exhaust. Now much cleaner exhaust is
ejected into the atmosphere via a stack.

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Fig.6 Main accessories of Rankine cycle - Cooling tower, Boiler furnace, ESP & Chimney
Optimizing a Thermal plant performance
Thereare various flow parameters which haveto be fine-tuned in order to get
optimum performance from a thermal power plant.Lowering the condenser
temperature or raising the average boiler temperature will result in a high
efficiency power plant cycle according to the 2nd law of thermodynamics
(Carnot efficiency),most of the performance improving technologies are
working on this idea. Some latest trends are listed below.
1. Expanding Turbine After Saturation
Expanding thesteamin theturbineeven after reaching thesaturation point
may be a dangerous affair. As the steam goes below saturation, wetness of
the steam increases. These condensed water droplets collide with the
turbine blades rotating at a high speed, thus it can cause extreme tip
erosion to the blades. Turbine blade tip erosion is shown in figure below.
But as you expand more you will be able to absorb more energy from the
steam, thus increasing power plant efficiency. Up to 15% wetness level is
considered to be safe for steam turbine operation. So most of the steam
turbine will expand up to this point in order to extract maximum energy
from the fluid. This is shown in figure below.

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Fig.7 Expanding turbine below saturation point in order to gain maximum power from steam
2. Raising average boiler temperature
If you can increasetheaverageheat addition temperatureof the boiler, that
will result in a power plant with higher efficiency. One way to do this is to
increasethecompressor pressure. This will shift the saturation point of the
fluid to a higher level, thus providing higher average temperature of heat
addition. This is shown in thefigurebelow. The blueline represents change
in the cycle after raising the compressor pressure.
Fig.8 Raising compressor pressure in order achieve higher average boiler temperature

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Conclusion
Company has proposed to set-up 500 MW Coal fired Thermal
Power Project based on Super Critical Technology. State Government has
supported this Project and has issued letter of support to provide all kind of
administrativesupportrequired. TheCompany has already acquired the land
required for the Main plant from IndustrialDevelopment Corporation and has
made the requisitepayments. Theremaining required land has been identified
and the process of acquisition is underway.
TheProject requires about 351,000 Tonnes coal based on average Operational
at 87.63 % PLF, generation at 462 MW Appropriate arrangements are
proposed to be done. The water is taken from two barrages Lower Mun
barrageand upper Mun barragenear Balapur. The Project will require about
150 cubic meters per hour make-up water during operation. A raw water
reservoir of 25200m3 capacity to hold 7 days requirement for plant
requirement of water will be constructed at the plant site. Of the total 500
MW of power is proposed to be sold as 4.15 as per CERC tariff. Considering
the cost of generation of Rs. 2.35 per unit, company does not envisage any
difficulties in selling the power through merchant route. Power Evacuation
will be throughtwodouble circuit 440 KV transmission lines connecting the
Project to the MSEB substation and State MAHAGENCO substation.

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Agnihotri College of engineering
Nagthana, wardha
The student of Agnihotri College of engineering, wardha had gone for
an industrialvisit toparas thermalpower station, akola and had learned about
thepower generation. Suchindustrialvisit help the student in understanding
the practical application side of the course

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DEPARTMENTOFELeCTRICALENGINEERING3 RDYEAR
Reference
1. "Diagramof a typicalcoal-fired thermalpower station" (PDF).
Retrieved 21 April 2013.
2. "Coal supply to various power stations" (PDF). Retrieved 21 April 2013.
3. "Indian Railways, CIL to collaboratefor additionalcoaltransport
capacity". Miningweekly.com, 14 February 2013. Retrieved 21 April
2013.
http://www.learnengineering.org/2013/01/thermal-power-plant-working.html
http://indianpowersector.com/home/power-station/thermal-power-plant/
http://www.electrical4u.com/thermal-power-generation-plant-or-thermal-power-station/
http://wikimapia.org/10530304/Paras-Thermal-Power-Station-MAHAGENCO

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OUR EXPERIENCE FROM THE INDUSTRIAL VISIT:
After completing the industrial visit, we have upgraded our knowledge at a
very great level. It was a good learning experience. In each and every
department, wegot some or theother new ideas and new thinking which was
necessary for development.
ThankYou