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DIESEL ELECTRIC POWER STATIONS�

FACULTY- ER. GOSTA PANDA

SEMESTER- 6TH, MECHANICAL

SUBJECT- POWER STATION ENGINEERING

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  • Introduction:

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  • Diesel power plants produce power in the range of 2 to 50 MW.

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  • They are used as standby sets for continuity of supply such as hospitals, telephone exchanges, radio stations, cinema theatres and industries.

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  • They are suitable for mobile power generation and widely used in railways and ships.

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Layout of a Diesel power plant

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Layout of a Diesel power plant…

  1. Diesel engine…
  2. The fuel burns and the burnt gases expand to do work on the moving part inside the cylinder called piston.
  3. This movement of the piston rotates a flywheel and the engine is directly coupled to electric generator.
  4. The gases after expansion inside the cylinder is exhausted into the atmosphere and passes through a silencer in order to reduce the noise.

2. Starting system:

  • Diesel engine used in diesel power plants is not self starting. The engine is started from cold condition with the help of an air compressor.

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Layout of a Diesel power plant…

3. Fuel supply system:

  • Fuel from the storage tank is pumped through a filter into a smaller tank called all day tank. This tank supplies the daily requirements of the diesel engine.
  • The all day tank is placed high so that the fuel flows to the engine under gravity with sufficient pressure.

4. Air intake system :

  • The air required for the combustion of fuel inside the diesel engine cylinder is drawn through the air filter. The purpose of the filter is to remove dust from the incoming air.
  • The dry filter may be made of

felt, wood or cloth.

  • In wet filter, oil bath is used.

In this the air passes over a

bath of oil where the dust

particles get coated on the oil.

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Layout of a Diesel power plant…

5. Exhaust system:

  • The exhaust gases coming out of the engine is very noisy. In order to reduce the noise a silencer(muffler) is used.

6. Cooling system:

  • The temperature of the burning fuel inside the engine cylinder is in the order of 15000C to 20000C. In order to lower this temperature water is circulated around the engine.
  • The water envelopes(water jacket) the engine. The heat from the cylinder, piston, combustion chamber etc., is carried by the circulating water.
  • The hot water leaving the jacket is

passed through the heat exchanger

  • The heat from the heat exchanger is carried away by the raw water circulated through the heat exchanger and is cooled in the cooling tower.

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Layout of a Diesel power plant…

  1. Lubricating system:
  2. This circuit includes lubricating oil tank, oil pump and oil cooler.
  3. The purpose of the lubrication system is to reduce the wear of the engine moving parts. Part of the cylinder such as piston, shafts, valves must be lubricated.
  4. Lubrication also helps to cool the engine.
  5. In the lubrication system the oil is pumped from the lubricating oil tank through the oil cooler where the oil is cooled by the cold water entering the engine.
  6. The hot oil after cooling the moving parts return to the lubricating oil tank.

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Diesel power plant…

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22 March 2022

  • Advantages of Diesel power plant :
  • It can respond to varying loads without any difficulty.
  • It occupies less space.
  • For the same capacity diesel power plant is compact and smaller than a

thermal power plant.

  • Diesel power plants are more efficient than steam power plants in the range

of 150 MW capacity.

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  • Disadvantages of Diesel power plant :
  • High operating cost.
  • High maintenance and lubrication cost.
  • The capacity of a diesel plant is limited. They cannot be constructed in

large sizes.

  • In a diesel plant noise is a serious problem.
  • Diesel power plants cannot supply over loads continuously where as steam

power plants can work under 25% overload continuously.

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THANK YOU