Steam (thermal) power station

Stored energy of coal is converted to the heat energy by combustion. That heat energy is converted into the electricity.

Arrangement of steam power station

 

Coal and ash handling plant

Coal handling plant

In here coal is crushed into small particles to increase their surface area. Increasing of surface area help to burn them easily and completely. Then crushed coal is send to the boiler by conveyor belts.

Ash handling plant

After burning the coal in the boiler the ash is send to the ash handling plant and then to the ash storage.

Steam generating plant

Boiler

Combust the coal and by using that heat it makes high pressure and high temperature steam. The flue gases from the boiler is sent through super heater, economizer, air preheater and finally release to atmosphere through chimney.

There are two types of boilers

Water tube boiler- water flow through tubes inside the boiler and hot gases flow over that tubes.

Fire tube boiler- hot air flows through tubes inside the boiler which filled with water.

Super heater

Boiler send wet steam to the super heater. In here that steam is further heated (above the boiling temperature) with the help of temperature in flue gases. Therefore the thermal efficiency can be increased. Another advantage is damages to the turbine blades can be prevented. Because if there are water drops in the steam it make damages to the turbine blades. But output steam from super heater is completely dry. There are two types of super heaters radiant super heater and convection super heater.

Then the super-heated steam is fed into the turbine via main valve.

Economizer

This make water heated before supply to the boiler by using heat in the flue gases.

Air preheater

This fed air from the atmosphere and heated them before supply to the boiler by using flue gases.  

Steam turbine

Through main valve superheated dry steam is fed to the steam turbine. While passing through the turbine heat energy is converted to the mechanical energy. Then via an alternator that mechanical energy is converted to the electrical energy.

Cooling system

Steam after rotating the turbine is sent to the condenser then in cooling towers water is cooled. After cooling that water is sent through economizer (to heat to some temperature value) and then send to the boiler.