Recruitment and Retention Policy in Thermal Power Plants Project

8/2/2019 Recruitment and Retention Policy in Thermal Power Plants Project

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Vocational Tra ining Report

On

Process of thermal powergeneration in power plants

Submitted By:-

Gaurav Rajoria

B.Tech(2008-12)

National Institute Of Technology

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8 Conclusion

9 Bibliography

1. Objective s Of Study -

The following are the objectives of the study:-

To gather knowledge about CSEB and its potential in power generation.

To gather the knowledge about installed capacity of different units andfuture projects proposed by CSEB.

To study process of thermal power generation.

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To study the functioning of thermal power plant and its components.

To study the basic thermodynamic cycle involved in process of thermalpower generation.

To understand the practical implication of the theoretical knowledge aboutimplementation of concepts of electronics in process of thermal powergeneration.

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2. Introduction (CSEB )

The Chhattisgarh State Electricity Board has been reorganized into following five

companies in accordance with the provisions contained in the Electricity Act2003 by the Govt. of Chhattisgarh vide Notification dated 19.12.2008.

Chhattisgarh State Power Holding Company Limited

Chhattisgarh State Power Generation Company Limited

Chhattisgarh State Power Transmission Company Limited

Chhattisgarh State Power Distribution Company Limited

Chhattisgarh State Power Trading Company Limited

Unit wise Installed Capacity, Date of Commissioning & Date ofCommercial Generation

S.No. Unit No. Installed Capacity(MW)

Date ofCommissio

ning

Date ofCommer

cialGenerati

on

Thermal Power Stations (1786 MW)

1 Korba East Thermal Power Station (440 MW)

Power House No. II

I 505-Sep-

1966

II 50 16-May-1967

III 5023-Mar-

1968

IV 5031-Oct-

1968

Total 200

Power House No. III

I 12027-Apr-

1976

II 1205-Apr-1981

Total 240

2 Korba East, Dr. Shyama Prasad Mukherjee Thermal Power Station (500 MW)

I 25030-Mar-

200727-Jun-

2008

II 250 11-Dec- 30-Nov-

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http://www.cseb.gov.in/csphcl/index.htmhttp://www.cseb.gov.in/cspgcl/index.htmhttp://www.cseb.gov.in/csptcl/index.htmhttp://www.cseb.gov.in/cspdcl/index.htmhttp://www.cseb.gov.in/csptrdcl/index.htmhttp://www.cseb.gov.in/cspgcl/index.htmhttp://www.cseb.gov.in/csptcl/index.htmhttp://www.cseb.gov.in/cspdcl/index.htmhttp://www.cseb.gov.in/csptrdcl/index.htmhttp://www.cseb.gov.in/csphcl/index.htm


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2007 2008

Total 500

3 Korba West, HasdeoThermal Power Station (840 MW)

I 210

21-Jun-

1983

II 21031-Mar-

1984

III 21026-Mar-

1985

IV 21013-Mar-

1986

Total 840

Hydel Power Stations (138.70 MW)

1 Mini-Mata Hasdeo Bango Hydel Power Station (120 MW)

I 4021-Mar-

1994

II 4021-Nov-

1994

III 4011-Jan-

1995

Total 120

2 Gangrel Hydel Power Station (10 MW)

I 2.52-Apr-2004

28-Jul-2004

II 2.529-Jun-

20044-Aug-

2004

III 2.517-Oct-

20043-May-

2005

IV 2.55-Nov-

200423-May-

2005

Total 10

3 Sikasar Hydel Power Station (7 MW)

I 3.53-Sep-

2006

II 3.53-Sep-

2006

Total 7

4 Korba West Mini/ Micro Hydel Power Station (1.7 MW)

I 0.85 12-Jan-2003

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II 0.8529-May-

20094-Aug-

2009

Total 1.7

Other Power Stations (6 MW)

1 Bhoramdev Co-Gen, Kawardha (6 MW)

I 610-Aug-

2006

Total 6

Grand Total (Thermal +Hydel) 1924.7 MW

THERMAL GENERATION DATAUPTO JULY-2009

POWERHOUSE/ STATI

ON

PARTICULARS

UNIT JULY.-08YEARLY

UPTOJULY.-08

JULY.-09

YEARLYUPTO

JULY.-09

1 2 3 4 5 6 7

CSPGCL

Target MU 954 4074 975 4105

Gen MU 1064.86 4219.04 944.68 4189.99

PUF %80.98% 89.30%

71.33% 80.39%

Availability %88.67% 88.84%

80.64% 86.87%

Forced

outages (TubeLeakage)

MU 13.56 208.97 34.62 151.29

% 1.02% 4.01% 2.61% 2.90%No. 5 37 9 42

Forced outages

MU 32.22 132.12 19.50 74.65

% 2.43% 2.54% 1.47% 1.43%

No. 16 78 28 77

Plannedoutages

MU 104.28 240.31 202.23 458.25

%7.87% 4.61%

15.27% 8.79%

Partial lossesMU 109.40 411.40 123.29 337.67

% 8.26% 7.89% 9.31% 6.48%

Sp. Coal Cons. Kg/kwh 0.783 0.790 0.819 0.791

Sp. Oil Cons. ml/kwh 1.819 1.598 2.734 1.429

Aux. Cons. % 8.91% 9.02% 9.46% 9.05%

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3.Future Projects

Matnar Hydel Project (3x20 MW) District Bastar (C.G.)Matnar Hydel Project is located on river Indravati about 40 Km away from Districtheadquarter Jagdalpur. The estimated cost of the project is 292.22 Crores. Techno-economic clearance to the project has been accorded by Central Electricity Authority,Govt. of India, New Delhi in August 2004. The project is scheduled to be completed inthe 11th five year plan (2007-2012). The project will generate 177.18 Million units ofenergy per year. The tenders will be invited after getting clearance from MOEF.

Bodhghat Hydel Project (4x125 MW) District DantewaraBodhghat Hydel Project is located on river Indravati near village Barsoor, about 100 Kmfrom Jagdalpur. The project was earlier cleared by Planning Commission in 1979.However, subsequently on enactment of Forest Conservation Act 1980, the Ministry ofEnvironment & Forest conveyed its inability for diversion of required 5704 hectaresforest land. As a result all project activities were stopped.

After formation of the State of Chhattisgarh fresh efforts have been made by Govt.of Chhattisgarh & CSEB to revive the project. The Ministry of Environment and Forestin February 2004 has accorded In Principle Clearance for diversion of required forest

land for the project. Efforts are being made to revive the techno-economic clearancefrom Central Electricity Authority and clearance from Ministry of Environment Forest.The Detailed Project Report is being updated for submission to CEA.

The estimated cost of the project is Rs. 2350 Crores (at January 2004 Price level).

The Project will generate 1152 Million units of energy per year.

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4. Introduction To Thermal Power Plants

A thermal power plant is a power plant in which the prime moveris steam driven. Water is

heated, turns into steam and spins a steam turbine which either drives an electrical generator.

After it passes through the turbine, the steam is condensed in a condenserand 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 fuel sources. Some prefer to use the term energy

centerbecause such facilities convert forms ofheat energy into electrical energy.

Overview

Almost all coal,nuclear, geothermal, solar thermal electric, and waste incineration plants, as

well as many natural gas power plants are thermal. Natural gas is frequently combusted in gas

turbines as well as boilers. The waste heat from a gas turbine can be used to raise steam, in

a combined cycle plant that improves overall efficiency. Power plants burning coal are often

referred to collectively as fossil-fuel power plants.

Commercial electric utility power stations are most usually constructed on a very large scale

and designed for continuous operation. Electric power plants typically use three-phase or

individual-phase electrical generators to produce alternating current (AC) electric power at a

frequency of 50 Hz or 60 Hz (hertz, which is an AC sine wave per second) depending on its

location in the world. In some industrial, large institutional facilities, or other populated areas,

there are combined heat and power(CHP) plants, often called cogeneration plants, which

produce both power and heat for facility ordistrict heating or industrial applications. AC

electrical power can be stepped up to very high voltages for long distance transmission with

minimal loss of power. Steam and hot water lose energy when piped over substantial distance,

so carrying heat energy by steam or hot water is often only worthwhile within a local area or

facility, such as steam distribution for a ship or industrial facility or hot water distribution in a

local municipality.

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http://en.wikipedia.org/wiki/Power_planthttp://en.wiktionary.org/wiki/prime_moverhttp://en.wikipedia.org/wiki/Steamhttp://en.wikipedia.org/wiki/Steam_turbinehttp://en.wikipedia.org/wiki/Electrical_generatorhttp://en.wikipedia.org/wiki/Condensationhttp://en.wikipedia.org/wiki/Surface_condenserhttp://en.wikipedia.org/wiki/Rankine_cyclehttp://en.wikipedia.org/wiki/Heathttp://en.wikipedia.org/wiki/Energyhttp://en.wikipedia.org/wiki/Coalhttp://en.wikipedia.org/wiki/Nuclear_powerhttp://en.wikipedia.org/wiki/Geothermal_powerhttp://en.wikipedia.org/wiki/Solar_thermal_electrichttp://en.wikipedia.org/wiki/Natural_gashttp://en.wikipedia.org/wiki/Gas_turbinehttp://en.wikipedia.org/wiki/Gas_turbinehttp://en.wikipedia.org/wiki/Boilerhttp://en.wikipedia.org/wiki/Combined_cyclehttp://en.wikipedia.org/wiki/Fossil-fuel_power_planthttp://en.wikipedia.org/wiki/Electric_utilityhttp://en.wikipedia.org/wiki/Three-phasehttp://en.wikipedia.org/wiki/Electrical_generatorhttp://en.wikipedia.org/wiki/Hertzhttp://en.wikipedia.org/wiki/Combined_heat_and_power_planthttp://en.wikipedia.org/wiki/Combined_heat_and_power_planthttp://en.wikipedia.org/wiki/Combined_heat_and_power_planthttp://en.wikipedia.org/wiki/District_heatinghttp://en.wikipedia.org/wiki/Voltagehttp://en.wikipedia.org/wiki/Power_transmissionhttp://en.wikipedia.org/wiki/Power_planthttp://en.wiktionary.org/wiki/prime_moverhttp://en.wikipedia.org/wiki/Steamhttp://en.wikipedia.org/wiki/Steam_turbinehttp://en.wikipedia.org/wiki/Electrical_generatorhttp://en.wikipedia.org/wiki/Condensationhttp://en.wikipedia.org/wiki/Surface_condenserhttp://en.wikipedia.org/wiki/Rankine_cyclehttp://en.wikipedia.org/wiki/Heathttp://en.wikipedia.org/wiki/Energyhttp://en.wikipedia.org/wiki/Coalhttp://en.wikipedia.org/wiki/Nuclear_powerhttp://en.wikipedia.org/wiki/Geothermal_powerhttp://en.wikipedia.org/wiki/Solar_thermal_electrichttp://en.wikipedia.org/wiki/Natural_gashttp://en.wikipedia.org/wiki/Gas_turbinehttp://en.wikipedia.org/wiki/Gas_turbinehttp://en.wikipedia.org/wiki/Boilerhttp://en.wikipedia.org/wiki/Combined_cyclehttp://en.wikipedia.org/wiki/Fossil-fuel_power_planthttp://en.wikipedia.org/wiki/Electric_utilityhttp://en.wikipedia.org/wiki/Three-phasehttp://en.wikipedia.org/wiki/Electrical_generatorhttp://en.wikipedia.org/wiki/Hertzhttp://en.wikipedia.org/wiki/Combined_heat_and_power_planthttp://en.wikipedia.org/wiki/District_heatinghttp://en.wikipedia.org/wiki/Voltagehttp://en.wikipedia.org/wiki/Power_transmission


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History

Reciprocating steam engines have been used for mechanical power sources since the 18th

Century, with notable improvements being made by James Watt. The very first commercial

central electrical generating stations in New York and London, in 1882, also used reciprocatingsteam engines. As generator sizes increased, eventually turbines took over.

Efficiency

Poweris energy per unit time. The power output or capacity of an electric plant can be

expressed in units of megawatts electric (MWe). The electric efficiency of a conventional

thermal power station, considered as saleable energy (in MWe) produced at the plant busbars

as a percent of the heating value of the fuel consumed, is typically 33% to 48% efficient. This

efficiency is limited as all heat engines are governed by the laws

ofthermodynamics (See: Carnot cycle). The rest of the energy must leave the plant in the form

of heat. This waste heatcan go through a condenserand be disposed of with cooling wateror

in cooling towers. If the waste heat is instead utilized fordistrict heating, it is

called cogeneration. An important class of thermal power station are associated

with desalination facilities; these are typically found in desert countries with large supplies

ofnatural gas and in these plants, freshwater production and electricity are equally important

co-products.Since the efficiency of the plant is fundamentally limited by the ratio of the absolute

temperatures of the steam at turbine input and output, efficiency improvements require use of

higher temperature, and therefore higher pressure, steam..

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http://en.wikipedia.org/wiki/James_Watthttp://en.wikipedia.org/wiki/Power_(physics)http://en.wikipedia.org/wiki/Energyhttp://en.wikipedia.org/wiki/Timehttp://en.wikipedia.org/wiki/Thermodynamichttp://en.wikipedia.org/wiki/Carnot_cyclehttp://en.wikipedia.org/wiki/Waste_heathttp://en.wikipedia.org/wiki/Surface_condenserhttp://en.wikipedia.org/wiki/Cooling_waterhttp://en.wikipedia.org/wiki/Cooling_towerhttp://en.wikipedia.org/wiki/District_heatinghttp://en.wikipedia.org/wiki/Cogenerationhttp://en.wikipedia.org/wiki/Desalinationhttp://en.wikipedia.org/wiki/Natural_gashttp://en.wikipedia.org/wiki/James_Watthttp://en.wikipedia.org/wiki/Power_(physics)http://en.wikipedia.org/wiki/Energyhttp://en.wikipedia.org/wiki/Timehttp://en.wikipedia.org/wiki/Thermodynamichttp://en.wikipedia.org/wiki/Carnot_cyclehttp://en.wikipedia.org/wiki/Waste_heathttp://en.wikipedia.org/wiki/Surface_condenserhttp://en.wikipedia.org/wiki/Cooling_waterhttp://en.wikipedia.org/wiki/Cooling_towerhttp://en.wikipedia.org/wiki/District_heatinghttp://en.wikipedia.org/wiki/Cogenerationhttp://en.wikipedia.org/wiki/Desalinationhttp://en.wikipedia.org/wiki/Natural_gas


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5.Basic Diagram Of A Thermal PowerPlant

6. Parts Of A Thermal Power Plant

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1. Cooling tower 10. Steam Control valve 19. Superheater

2. Cooling water pump 11. High pressure steam turbine 20. Forced draught (draft) fan

3. transmission line (3-phase) 12. Deaerator 21. Reheater

4. Step-up transformer(3-phase) 13. Feedwater heater 22. Combustion air intake

5. Electrical generator(3-phase) 14. Coal conveyor 23. Economiser

6. Low pressure steam turbine 15. Coal hopper 24. Air preheater

7. Condensate pump 16. Coal pulverizer 25. Precipitator

8. Surface condenser 17. Boiler steam drum 26. Induced draught (draft) fan

9. Intermediate pressure steam turbine 18. Bottom ash hopper 27. Flue gas stack
http://en.wikipedia.org/wiki/Cooling_towerhttp://en.wikipedia.org/wiki/Control_valvehttp://en.wikipedia.org/wiki/Superheaterhttp://en.wikipedia.org/wiki/Cooling_tower_systemhttp://en.wikipedia.org/wiki/Steam_turbinehttp://en.wikipedia.org/wiki/Centrifugal_fanhttp://en.wikipedia.org/wiki/Electrical_power_transmissionhttp://en.wikipedia.org/wiki/Three-phasehttp://en.wikipedia.org/wiki/Deaeratorhttp://en.wikipedia.org/wiki/Transformerhttp://en.wikipedia.org/wiki/Three-phasehttp://en.wikipedia.org/wiki/Feedwater_heaterhttp://en.wikipedia.org/wiki/Combustionhttp://en.wikipedia.org/wiki/Electrical_generatorhttp://en.wikipedia.org/wiki/Three-phasehttp://en.wikipedia.org/wiki/Coalhttp://en.wikipedia.org/wiki/Conveyorhttp://en.wikipedia.org/wiki/Economiserhttp://en.wikipedia.org/wiki/Steam_turbinehttp://en.wikipedia.org/wiki/Coalhttp://en.wikipedia.org/wiki/Air_preheaterhttp://en.wikipedia.org/wiki/Condensate_pumphttp://en.wikipedia.org/wiki/Pulverizerhttp://en.wikipedia.org/wiki/Electrostatic_precipitatorhttp://en.wikipedia.org/wiki/Surface_condenserhttp://en.wikipedia.org/wiki/Steam_drumhttp://en.wikipedia.org/wiki/Centrifugal_fanhttp://en.wikipedia.org/wiki/Steam_turbinehttp://en.wikipedia.org/wiki/Bottom_ashhttp://en.wikipedia.org/wiki/Flue_gas_stackhttp://en.wikipedia.org/wiki/File:PowerStation2.svghttp://en.wikipedia.org/wiki/Cooling_towerhttp://en.wikipedia.org/wiki/Control_valvehttp://en.wikipedia.org/wiki/Superheaterhttp://en.wikipedia.org/wiki/Cooling_tower_systemhttp://en.wikipedia.org/wiki/Steam_turbinehttp://en.wikipedia.org/wiki/Centrifugal_fanhttp://en.wikipedia.org/wiki/Electrical_power_transmissionhttp://en.wikipedia.org/wiki/Three-phasehttp://en.wikipedia.org/wiki/Deaeratorhttp://en.wikipedia.org/wiki/Transformerhttp://en.wikipedia.org/wiki/Three-phasehttp://en.wikipedia.org/wiki/Feedwater_heaterhttp://en.wikipedia.org/wiki/Combustionhttp://en.wikipedia.org/wiki/Electrical_generatorhttp://en.wikipedia.org/wiki/Three-phasehttp://en.wikipedia.org/wiki/Coalhttp://en.wikipedia.org/wiki/Conveyorhttp://en.wikipedia.org/wiki/Economiserhttp://en.wikipedia.org/wiki/Steam_turbinehttp://en.wikipedia.org/wiki/Coalhttp://en.wikipedia.org/wiki/Air_preheaterhttp://en.wikipedia.org/wiki/Condensate_pumphttp://en.wikipedia.org/wiki/Pulverizerhttp://en.wikipedia.org/wiki/Electrostatic_precipitatorhttp://en.wikipedia.org/wiki/Surface_condenserhttp://en.wikipedia.org/wiki/Steam_drumhttp://en.wikipedia.org/wiki/Centrifugal_fanhttp://en.wikipedia.org/wiki/Steam_turbinehttp://en.wikipedia.org/wiki/Bottom_ashhttp://en.wikipedia.org/wiki/Flue_gas_stack


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Coal Handling Plant (CHP):-

Extent of work: - In brief we can say that receipt of coal from coal mines, weighing of coal,

crushing it to required size and transferring the quanta of coal to various coal mill bunkers. This

is the responsibility and duty of the CHP and its staff.

Receipt of Coal:-

Normally Thermal Power Station receives the coal by three modes of transportation.

1. By Railway (80-90% of the requirement is fulfilled by this way)

2. By Road ( if required 5-10% of the requirement is fulfilled by this way )

3. By Arial ropeways

Arial ropeway is available only to the power stations which are near the coal mines

Cost of coal transportation by road is much higher than that for rail transport hence most of

the coal requirement of the power stations is fulfilled by railway transport.

Major auxiliaries of CHP:-

1. Wagon Tipplers

2. Vibrating Feeders

3. Conveyor Belts

4. Coal Crushers

5. Trippers

6. Electromagnetic Separators.7. Dust extraction systems

8. Gas Extractor.

1.Wagon Tipplers:-

These are the giant machines having gear boxes and motor assembly and are used to unload

the coal wagons into coal hoppers in very less time (e.g. 20 wagons/hr. or more).

2.Vibrating Feeders:-

These are electromagnetic vibrating feeders or sometimes in the form of dragging chains which

are provided below the coal hoppers. This equipment is used for controlled removal of coal

from coal hoppers.

3.Conveyers:-

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A conveyor system is a common piece of mechanical handling equipment that moves materials

from one location to another. Conveyors are especially useful in applications involving the

transportation of heavy or bulky materials. Conveyor systems allow quick and efficient

transportation for a wide variety of materials, which make them very popular in the material

handling and packaging industries. Many kinds of conveying systems are available, and are

used according to the various needs of different industries.

4.Coal Crushers:-

We receive the coal in the form of odd shaped lumps. These lumps are to be crushed to

required size. These lumps are crushed by coal crushers.

5.Trippers:-

These are the motorized or manually operated machines and are used for feeding the coal to

different coal bunkers as per their requirement.

6.Electromagnetic Separators:-Electromagnets are used for removing of Iron and magnetic impurities from the coal.

7.Dust Extraction System:-

This system is provided in CHP for suppression of coal dust in coal handling plant.

8.Gas Extractors:-

Gas extractors are provided at the bunker level to remove all types of poisonous and non

poisonous gases from the working area.

Operational Cycles:-1. Normal Bunkering cycle.

2. Stacking cycle.

3. Reclaiming Cycle.

1.Normal Bunkering Cycle:-

Shifting of coal received from coal wagons directly to coal bunkers is normal bunkering cycle.

2.Stacking Cycle:-

When there is no coal requirement at coal bunkers even then CHP has to unload the received

coal which is stacked at open ground called yard. This is stacking cycle.

3.Reclaiming Cycle:-

As and when coal wagons are not available the requirement of coal bunkers is fulfilled from the

stacked coal this is reclaiming cycle.

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In the vast majority of transformers, the windings are coils wound around a ferromagnetic

core, air-core transformers being a notable exception.

Transformers range in size from a thumbnail-sized coupling transformer hidden inside a

stage microphone to huge units weighing hundreds of tons used to interconnect portions

ofpower grids. All operate with the same basic principles, although the range of designs is

wide. While new technologies have eliminated the need for transformers in some electronic

circuits, transformers are still found in nearly all electronic devices designed forhousehold

("mains") voltage . Transformers are essential for high voltage power transmission, which

makes long distance transmission economically practical.

STEAM TURBINE

A steam turbine is a mechanical device that extracts thermal energy from pressurized steam,

and converts it into rotary motion. Its modern manifestation was invented by Sir Charles

Parsons in 1884.

It has almost completely replaced the reciprocating piston steam engine primarily because of its

greater thermal efficiency and higherpower-to-weight ratio. Because the turbine

generates rotary motion, it is particularly suited to be used to drive an electrical generator

about 80% of all electricity generation in the world is by use of steam turbines. The steam

turbine is a form ofheat engine that derives much of its improvement in thermodynamic

efficiency through the use of multiple stages in the expansion of the steam, which results in a

closer approach to the ideal reversible process.

Steam generator

In fossil-fueled power plants, steam generatorrefers to a furnace that burns the fossil fuel toboil water to generate steam. In the nuclear plant field, steam generatorrefers to a specific type

of large heat exchangerused in a pressurized water reactor(PWR) to thermally connect the

primary (reactor plant) and secondary (steam plant) systems, which of course is used to

generate 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 heat

recovery steam generators (HRSG) which utilize heat from some industrial process. The steam

generating boiler has to produce steam at the high purity, pressure and temperature required

for the steam turbine that drives the electrical generator. A fossil fuel steam generator includes

an economizer, a steam drum, and the furnace with its steam generating tubes

and superheatercoils. Necessary safety valves are located at suitable points to avoid

excessive boiler pressure. The air and flue gas path equipment include: forced draft

(FD) fan, air preheater(APH), boiler furnace, induced draft (ID) fan, fly ash collectors

(electrostatic precipitatororbaghouse) and the flue gas stack.

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Redundancy of key components is provided by installing duplicates of the FD fan, APH, fly ash

collectors and ID fan with isolating dampers.

Boiler furnace and steam drum

Once water inside the boilerorsteam generator, the process of adding the latent heat of

vaporization orenthalpy is underway. The boiler transfers energy to the water by the chemicalreaction of burning some type of fuel.

The water enters the boiler through a section in the convection pass called the economizer.

From the economizer it passes to the steam drum. Once the water enters the steam drum it

goes down the downcomers to the lower inlet waterwall headers. From the inlet headers the

water rises through the waterwalls and is eventually turned into steam due to the heat being

generated by the burners located on the front and rear waterwalls (typically). As the water is

turned into steam/vapor in the waterwalls, the steam/vapor once again enters the steam drum.

The steam/vapor is passed through a series of steam and water separators and then dryers

inside the steam drum. The steam separators and dryers remove water droplets from the steam

and the cycle through the waterwalls is repeated. This process is known as natural circulation.

The boiler furnace auxiliary equipment includes coal feed nozzles and igniter guns, soot

blowers, water lancing and observation ports (in the furnace walls) for observation of the

furnace interior. Furnace explosions due to any accumulation of combustible gases after a trip-

out are avoided by flushing out such gases from the combustion zone before igniting the coal.

The steam drum (as well as the superheater coils and headers) have air vents and drains

needed for initial startup. The steam drum has internal devices that removes moisture from the

wet steam entering the drum from the steam generating tubes. The dry steam then flows into

the superheater coils.

SuperheaterFossil fuel power plants can have a superheaterand/or reheater section in the steam

generating furnace. Nuclear-powered steam plants do not have such sections but produce

steam at essentially saturated conditions. In a fossil fuel plant, after the steam is conditioned by

the drying equipment inside the steam drum, it is piped from the upper drum area into tubes

inside an area of the furnace known as the superheater, which has an elaborate set up of

tubing where the steam vapor picks up more energy from hot flue gases outside the tubing and

its temperature is now superheated above the saturation temperature. The superheated steam

is then piped through the main steam lines to the valves before the high pressure turbine.

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. This

is what is called as thermal power.

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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. The pulverizers may be ball mills, rotating drum grinders, or

other types of grinders.

Some power stations burn fuel oil rather than coal. The oil must kept warm (above its pour

point) in the fuel oil storage tanks to prevent the oil from congealing and becoming

unpumpable. The oil is usually heated to about 100 C before being pumped through the

furnace fuel oil spray nozzles.

Boilers in some power stations use processed natural gas as their main fuel. Other power

stations may use processed natural gas as auxiliary fuel in the event that their main fuel supply

(coal or oil) is interrupted. In such cases, separate gas burners are provided on the boiler

furnaces.

Air path

External fans are provided to give sufficient air for combustion. The forced draft fan takes air

from the atmosphere and, first warming it in the air preheater for better combustion, injects it via

the air nozzles on the furnace wall.

The induced draft fan assists the FD fan by drawing out combustible gases from the furnace,

maintaining a slightly negative pressure in the furnace to avoid backfiring through any opening

Auxiliary systems

Fly ash collection

Fly ash is captured and removed from the flue gas by electrostatic precipitators or fabric bag

filters (or sometimes both) 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 pneumatically transported to storage silos for subsequent

transport by trucks or railroad cars.

Bottom ash collection and disposal

At the bottom of the furnace, there is a hopper for collection ofbottom ash. This hopper is

always filled with water to quench the ash and clinkers falling down from the furnace. Some

arrangement is included to crush the clinkers and for conveying the crushed clinkers and

bottom ash to a storage site.asaBoiler make-up water treatment plant and storage

Since there is continuous withdrawal of steam and continuous return ofcondensate to the

boiler, losses due to blowdown and leakages have to be made up to maintain a desired water

level in the boiler steam drum. For this, continuous make-up water is added to the boiler water

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system. Impurities in the raw water input to the plant generally consist

ofcalcium andmagnesium salts which impart hardness to the water. Hardness in the make-up

water to the boiler will form deposits on the tube water surfaces which will lead to overheating

and failure of the tubes. Thus, the salts have to be removed from the water, and that is done by

a water demineralising treatment plant (DM). A DM plant generally consists of cation, anion,

and mixed bed exchangers. Any ions in the final water from this process consist essentially ofhydrogen ions and hydroxide ions, which recombine to form pure water. Very pure DM water

becomes highly corrosive once it absorbs oxygen from the atmosphere because of its very high

affinity for oxygen.

The capacity of the DM plant is dictated by the type and quantity of salts in the raw water input.

However, some storage is essential as the DM plant may be down for maintenance. For this

purpose, a storage tank is installed from which DM water is continuously withdrawn for boiler

make-up. The storage tank for DM water is made from materials not affected by corrosive

water, such as PVC. The piping and valves are generally of stainless steel. Sometimes, a

steam blanketing arrangement or stainless steel doughnut float is provided on top of the water

in the tank to avoid contact with air. DM water make-up is generally added at the steam space

of the surface condenser(i.e., the vacuum side). This arrangement not only sprays the water

but also DM water gets deaerated, with the dissolved gases being removed by an

airejectorattached to the condenser.

Steam turbine-driven electric generator

The steam turbine-driven generators have auxiliary systems enabling them to work

satisfactorily and safely. The steam turbine generator being rotating equipment generally has a

heavy, large diameter shaft. The shaft therefore requires not only supports but also has to be

kept in position while running. To minimise the frictional resistance to the rotation, the shaft has

a number ofbearings. The bearing shells, in which the shaft rotates, are lined with a low frictionmaterial like Babbitt metal. Oil lubrication is provided to further reduce the friction between shaft

and bearing surface and to limit the heat generated.

Barring gear

Barring gear(or "turning gear") is the mechanism provided to rotate the turbine generator shaft

at a very low speed after unit stoppages. Once the unit is "tripped" (i.e., the steam inlet valve is

closed), the turbine coasts down towards standstill. When it stops completely, there is a

tendency for the turbine shaft to deflect or bend if allowed to remain in one position too long.

This is because the heat inside the turbine casing tends to concentrate in the top half of the

casing, making the top half portion of the shaft hotter than the bottom half. The shaft therefore

could warp or bend by millionths of inches.

This small shaft deflection, only detectable by eccentricity meters, would be enough to cause

damaging vibrations to the entire steam turbine generator unit when it is restarted. The shaft is

therefore automatically turned at low speed (about one percent rated speed) by the barring

gear until it has cooled sufficiently to permit a complete stop.

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Condenser

The surface condenser is a shell and tube heat exchangerin which cooling water is circulated

through the tubes. The exhaust steam from the low pressure turbine enters the shell where it is

cooled and converted to condensate (water) by flowing over the tubes as shown in the adjacent

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diagram. Such condensers use steam ejectorsorrotary motor-driven exhausters for continuous

removal of air and gases from the steam side to maintain vacuum.

For best efficiency, the temperature in the condenser must be kept as low as practical in order

to achieve the lowest possible pressure in the condensing steam. Since the condenser

temperature can almost always be kept significantly below 100 C where the vapor pressure of

water is much less than atmospheric pressure, the condenser generally works undervacuum.

Thus leaks of non-condensible air into the closed loop must be prevented. Plants operating in

hot climates may have to reduce output if their source of condenser cooling water becomes

warmer; unfortunately this usually coincides with periods of high electrical demand forair

conditioning.

The condenser generally uses either circulating cooling water from a cooling towerto reject

waste heat to the atmosphere, or once-through water from a river, lake or ocean.

FLUE GAS STACK

Flue gas stack is a type ofchimney, a vertical pipe, channel or similar structure through

which combustion product gases called flue gases are exhausted to the outside air. Flue gases

are produced when coal, oil, natural gas, wood or any other fuel is combusted in an

industrial furnace, apower plant's steam-generating boiler, or other large combustion device.

Flue gas is usually composed ofcarbon dioxide (CO2) and water vapor as well as nitrogen and

excess oxygen remaining from the intake combustion air. It also contains a small percentage ofpollutants such as particulate matter, carbon monoxide, nitrogen oxides and sulfur oxides. The

flue gas stacks are often quite tall, up to 400 meters (1300 feet) or more, so as to disperse the

exhaust pollutants over a greater area and thereby reduce the concentration of the pollutants to

the levels required by governmental environmental policy and environmental regulation.

When the flue gases are exhausted from stoves, ovens, fireplaces, or other small sources

within residential abodes, restaurants, hotels, or other public buildings and small commercial

enterprises, their flue gas stacks are referred to as chimneys.

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Feedwater heater

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costs and also helps to avoid thermal shock to the boiler metal when the feedwater is

introduced back into the steam cycle.

Superheater

As the steam is conditioned by the drying equipment inside the drum, it is piped from the upper

drum area into an elaborate set up of tubing in different areas of the boiler. The areas known

as superheaterand reheater. The steam vapor picks up energy and its temperature is now

superheated above the saturation temperature. The superheated steam is then piped through

the main steam lines to the valves of the high pressure turbine.

Deaerator

Diagram of boiler feed water deaerator (with vertical, domed aeration section and horizontal

water storage section

A steam generating boiler requires that the boiler feed water should be devoid of air and other

dissolved gases, particularly corrosive ones, in order to avoid corrosion of the metal.Generally,

power stations use a deaeratorto provide for the removal of air and other dissolved gases from

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7. Description Of Rankine Cycle

The Rankine cycle is a cycle which converts heat into work. The heat is supplied externally to a

closed loop, which usually uses water. This cycle generates about 80% of all electric power

used throughout the world,[1] including virtually all solar thermal, biomass, coal andnuclearpower plants. It is named afterWilliam John Macquorn Rankine, a Scottish polymath.

Description

Physical layout of the four main devices used in the Rankine cycle

A Rankine cycle describes a model of steam operated heat engine most commonly found

in power generation plants. Common heat sources for power plants using the Rankine cycle are

the combustion ofcoal, natural gas and oil, andnuclear fission.

The Rankine cycle is sometimes referred to as a practical Carnot cycle as, when an efficient

turbine is used, the TS diagram begins to resemble the Carnot cycle. The main difference is

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that heat addition and rejection are isobaric in the Rankine cycle and isothermal in the

theoretical Carnot cycle. A pump is used to pressurize liquid instead of gas. This requires a

very small fraction of the energy compared to compressing a gas in a compressor (as in

the Carnot cycle).

The efficiency of a Rankine cycle is usually limited by the working fluid. Without the pressure

reaching super critical levels for the working fluid, the temperature range the cycle can operate

over is quite small: turbine entry temperatures are typically 565C (the creep limit of stainless

steel) and condenser temperatures are around 30C. This gives a theoreticalCarnot

efficiency of about 63% compared with an actual efficiency of 42% for a modern coal-fired

power station. This low turbine entry temperature (compared with a gas turbine) is why the

Rankine cycle is often used as a bottoming cycle incombined cycle gas turbine power stations.

The working fluid in a Rankine cycle follows a closed loop and is re-used constantly. The

watervaporwith entrained droplets often seen billowing from power stations is generated bythe cooling systems (not from the closed loop Rankine power cycle) and represents the waste

heat that could not be converted to useful work. Note that cooling towers operate using the

latent heat of vaporization of the cooling fluid. The white billowing clouds that form in cooling

toweroperation are the result of water droplets which are entrained in the cooling tower airflow;

they are not, as commonly thought, steam. While many substances could be used in the

Rankine cycle, water is usually the fluid of choice due to its favorable properties, such as

nontoxic and unreactive chemistry, abundance, and low cost, as well as its thermodynamic

properties.

One of the principal advantages the Rankine cycle holds over others is that during the

compression stage relatively little work is required to drive the pump, the working fluid being in

its liquid phase at this point. By condensing the fluid to liquid, the work required by the pump

consumes only 1% to 3% of the turbine power and contributes to a much higher efficiency for a

real cycle. The benefit of this is lost somewhat due to the lower heat addition temperature. Gas

turbines, for instance, have turbine entry temperatures approaching 1500C. Nonetheless, the

efficiencies of actual large steam cycles and large modern gas turbines are fairly well matched.

Processes of the Rankine cycle

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Ts diagram of a typical Rankine cycle operating between pressures of 0.06bar and 50bar

There are four processes in the Rankine cycle, these states are identified by number in diagramto the right.

Process 1-2: The working fluid is pumped from low to high pressure, as the fluid is a liquid

at this stage the pump requires little input energy.

Process 2-3: The high pressure liquid enters a boiler where it is heated at constant

pressure by an external heat source to become a dry saturated vapor.

Process 3-4: The dry saturated vapor expands through a turbine, generating power. This

decreases the temperature and pressure of the vapor, and some condensation may occur.

Process 4-1: The wet vapor then enters a condenserwhere it is condensed at a constant

pressure to become a saturated liquid.

In an ideal Rankine cycle the pump and turbine would be isentropic, i.e., the pump and turbine

would generate no entropy and hence maximize the net work output. Processes 1-2 and 3-4

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would be represented by vertical lines on the T-S diagram and more closely resemble that of

the Carnot cycle. The Rankine cycle shown here prevents the vapor ending up in the superheat

region after the expansion in the turbine,[1] which reduces the energy removed by the

condensers.

Real Rankine cycle (non-ideal)

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Rankine cycle with superheat

In a real Rankine cycle, the compression by the pump and the expansion in the turbine are not

isentropic. In other words, these processes are non-reversible and entropy is increased during

the two processes. This somewhat increases the powerrequired by the pump and decreases

the power generated by the turbine.

In particular the efficiency of the steam turbine will be limited by water droplet formation. As the

water condenses, water droplets hit the turbine blades at high speed causing pitting and

erosion, gradually decreasing the life of turbine blades and efficiency of the turbine. The easiest

way to overcome this problem is by superheating the steam. On the Ts diagram above, state 3

is above a two phase region of steam and water so after expansion the steam will be very wet.

By superheating, state 3 will move to the right of the diagram and hence produce a dryer steam

after expansion.

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8 . Conclusion-

In todays world scenario in which india is in adeveloping stage proper, and efficient use of fossilfuels becomes very important for its growth.What elsethan a thermal power plant can be a better option forproviding electricity in india.For efficient working ofthese power plants, expert technicians are requiredwho could control its functoning. This was mainobjective of my training, for gathering knowledge about

generation of thermal power in thermal power plantsand be a part of it. From my training experiences I haveconcluded that CSEB has been producing electicalenergy in best and proper manner by adopting thenecessary concepts of thermal power generation. Thedata gathered about thermal power generation by CSEBin the past shows that it had been providing the resultsin the past and had played a major contribution indevelopment of Chhattisgarh.

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9 . BIBLIOGRAPHY -

1. RECOMMENDED BOOKS:

Standard Handbook of Powerplant Engineering Modern Power Station Practice

2.CSEB DOCUMENTS:

Thermal generation data 2009 Published by CSEB

CSPGCLs unit wise installed capacity data

3.WEBSITES:

1. www.cseb.gov.in2. library.thinkquest.org3. en.wikipedia.org/wiki/Thermal Power Plant4. Search engines: Google & Bing

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Recruitment and Retention Policy in Thermal Power Plants Project

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