Thermal power stations

When we say thermal power stations, it really means a coal-fired power plant with steam turbines(ST). But , in common language, it may include diesel engine(DG) power plants, gas-turbine(GT) powered plants or even combined-cycle(CCY) power plants.

Coal-fired steam turbines:
Since coal is expected to be more abundant than other fossil fuels such as diesel, petrol, natural gas - and because of it's low cost , coal power plants are installed in most power systems as base load catering plants.

A coal power plant,  showing cooling tower

The turbine of a modern steam-turbine-generator

Gas-turbines:

The main elements of a gas-turbine are,
1.Compressor
2.Combustor
3.Turbine

A General Electric gas-turbine which was used in a US military jet-aircraft


Combined-cycle power plants:
In order to increase the efficieny of gas turbines, combined cycle plants were introduced. These plants utilise the still hot exhausts left out to the atmosphere to heat water pipes. this effects to be a steam turbine and significant efficiency improvement is done.

Model diagram of a CCY plant, showing a gas turbine and a steam turbine



Diesel-Engines:
Diesel engine powered plants are a kind of Internal combustion engines. Normally petrol-based (gasoline) engines are spark-ignitioned. This means every combustion cycle is initiated by a HV spark provided by spark-plugs. But big diesel-based engines are compression-ignitioned. The compression of air produces heat and, makes the incoming tiny particles of diesel get ignited.

main elements in a diesel engine are,
1. cylinder
2. Piston
3. nozzles
4. diesel pump
5. set of valves
6. air, oil, fuel filters
7. exhaust opening
8.silencer
etc...

Principle of diesel engine

from: www.rkm.com.au

3 major liquids are required for the correct operation of any diesel engine. Those are;
* good fuel (slag-free, water-free, dust-free diesel)

* good engine oil
*good cooling water (particle-free, calcium compound-free purified water)