Friday, 20 April 2018

How Electricity Produce In Coal Based Thermal Power Plant??

How Electricity Produce In Coal Based Thermal Power Plant?? 




Working And Process Of Coal Based Thermal Power Plant And How Will Be Produced The Electricity Produced In This Power Station,. 





Energy Generating [ By Electrical Generator  ] station which converts heat energy of coal combustion into electrical energy is known as a steam or thermal power station.





basically Energy Generation By Coal Base Thermal Power Plant.

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A Steam Power Station basically works on the Rankine cycle. Steam is produced in the boiler utilizing the heat of coal combustion.
Here Read The Different Types Of Electrical Energy Conversion : Electrical Energy Conversion 

The steam is then expanded in the prime mover (i.e Steam Turbine) and is condensed in a condenser to be fed into the boiler again.


The steam turbine drives The Alternator which converts mechanical energy of the turbine into electrical energy. This type of power station is suitable where coal and water are available in abundance and a large amount of electric power is to be generated



The Generated Energy efficiency of a conventional Thermal Power Station, considered salable energy produced as a percent of the heating value of the fuel consumed, is typically 33% to 48%. As with all heat engines, their efficiency is limited, and governed by the laws of thermodynamics.


Schematic Arrangement of Thermal Power Station


Although steam power station simply involves the conversion of heat of coal combustion into Electrical Energy, yet it embraces many arrangements for proper working and efficiency.

The schematic arrangement of a Modern Steam Power Station is shown in Figer.




The whole arrangement can be divided into the following stages for the sake of simplicity:


  • 1) Coal and ash handling arrangement
  • 2)Steam generating plant
  • 3)steam turbine
  • 4)Alternator
  • 5)Feed water
  • 6) Cooling arrangement




1. Coal and ash handling plant 

The coal is transported to the power station by road or rail and is stored in the coal storage plant.

Storage of coal is primarily a matter of protection against coal strikes, failure of transportation system and general coal shortages.

From the Coal Storage Plant, coal is delivered to the coal handling plant where it is pulverised (i.e., crushed into small pieces) in order to increase its surface exposure, thus promoting rapid combustion without using large quantity of excess air.

The pulverised coal is fed to the boiler by belt conveyors. The coal is burnt in the boiler and the ash produced after the complete combustion of coal is removed to the ash handling plant and then delivered to the ash storage plant for disposal.


The removal of the ash from the boiler furnace is necessary for proper burning coal.


 2, Steam Generating Plant




The Steam Generating plant consists of a boiler for the production of steam and other auxiliary equipment for the utilisation of flue gases

Boiler:

The heat of combustion of coal in the boiler is utilised to convert water into steam at High Temperarure And Pressure.

The flue gases from the boiler make their journey through superheater, economiser, air pre-heater and are finally exhausted to atmosphere through the chimney.





Superheater

The steam produced in the boiler is wet and is passed through a superheater where it is dried and superheated (i.e., steam temperarure increased above that of boiling point of water) by the flue gases on their way to chimney. Superheating provides two principal benefits. Firstly, the overall efficiency is increased.

Secondly, too much condensation in the last stages of turbine (which would cause blade corrosion is avoided.

The superbeared steam from the superheater is fed to steam turbine through the main valve.


Economiser

An economiser is essentially a Feed Water Heater and derives heat from the flue gases for this purpose.

The feed water is fed to the economiser before supplying to the boiler The economiser extracts a part of heat offlue gases to increase the feed water temperarure.




 Air preheater

An air preheater increases the temperature of the air supplied for coal burning by deriving heat from flue gases.

Air is drawn from the atmosphere by a forced draught fan and is passed through air preheater before supplying to the boiler fumace.

The air preheater extracts hear from flue gases and increases the temperarure of air used for coal combustion.

The principal benefits of preheating the air are: increased thermal efficiency and increased steam capacity per square metre of boiler surface



3. Steam turbine: 

The dry and superheated steam from the superhearer is fed to the steam turbine through main valve.

The heat energy of steam when passing over the blades of turbine is converted into mechanical energy.

After giving heat energy to the turbine, the steam is exhausted to the condenser which condenses the exhausted steam by means of cold water circulation.




4. Alternator

The steam turbine is coupled to an alternator.

The alternator converts mechanical energy of turbine into electrical energy.


The electrical output from the alternator is delivered to the bus bars through transformer, circuit breakers and isolators


5. Feed water:

 The condensate from the condenser is used as feed water to the boiler. Some water may be lost in the cycle which is suitably made up from external source.

The feed water on its way to the boiler is heated by water heaters and economiser. This helps in raising the overall efficiency of the plant.



6) Cooling arrangement

 In order to improve the efficiency of the plant, the steam exhausted from the turbine is condensed by means of a condenser.

Water is drawn from a natural source of supply such as a river, canal or lake and is circulated through the condenser.


  • The circulating water takes up the heat of the exhausted steam and itself becomes hot. This hot water coming out from the condenser is discharged at a suitable location down the river. 

  • In case the availability of water from the source of supply is not assured throughout the year, cooling towers are used. 


During the scarcity of water in the river, hot water from the condenser is passed on to the cooling towers where it is cooled.

The cold water from the cooling tower is reused in the condenser.

Question Part Related To This Article Which Helps You For More Understanding :


1)What is a Thermal Power Plant??
Ans:A generating station which converts heat energy of coal combustion into electrical energy is known as a steam or thermal power station


2)Thermal Power Plant is suitable for ____????
Ans:This type of power station is suitable where coal and water are available in abundance and a large amount of electric power is to be generated.


3)What is function of super heater in thermal power plant??
Ans: The steam produced in the boiler is wet and is passed through a superheater where it is dried and superheated (i.e., steam remperarure increased above that of boiling point of water) by the flue gases on their way to chimney.

Superheating provides two principal benefits. Firstly, the overall efficiency is increased. Secondly, too much condensation in the last stages of turbine (which would cause blade corrosion is avoided. The superbeared steam from the superhearer is fed to steam turbine through the main valve.


4) What is work of economiser in thermal power plant??
Ans: An economiser is essentially a feed water heater and derives heat from the flue gases for this purpose.

The feed water is fed to the economiser before supplying to the boiler The economiser extracts a part of heat offlue gases to increase the feed water temperarure.


5)Which type And Why cooling arrangement are required in thermal power plant??
Ans:  In order to improve the efficiency of the plant, the steam exhausted from the turbine is condensed by means of a condenser.

Water is drawn from a natural source of supply such as a river, canal or lake and is circulated through the condenser.

The circulating water takes up the heat of the exhausted steam and itself becomes hot.

This hot water coming out from the condenser is discharged at a suitable location down the river.

In case the availability of water from the source of supply is not assured throughout the year, cooling towers are used.

During the scarcity of water in the river, hot water from the condenser is passed on to the cooling towers where it is cooled. The cold water from the cooling tower is reused in the condenser .




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