THERMAL POWER PLANT (COAL FIRED)

MECHANICAL TIPS AND STUDY MATERIAL

Primary fuel used ----- COAL
A thermal power plant is source of energy (electricity) generation, by production of large amount of heat caused by burning fuel. Earlier we discussed nuclear power plant is also a thermal power plant. Like wise other plant like Geo thermal, etc are categorized depending upon the type of fuel used. The operation and construction of all such plant are more or less same with slight modification.

The main component of coal fired thermal power plants are

  • Boiler
  • Coolant
  • Turbine
  • Condenser
  • Generator
Boiler


It is a tall rectangular furnace with cross web steel tubes which can handle very high pressure. The dimension of boiler can be up to 135 meter tall and 17 meters wide.


When air - fuel mixture is burned in the boiler, the water around it absorbs the the heat and starts circulating in the pressure tubes along the periphery. Water gets converted to steam under such high temperature and at the its outlet the steam may be as heat as 550°C. 

A boiler is furnace where the fuel (coal) is burned to produce energy. We know that coal is made up of carbon. When the fuel is burned in boiler, carbon in the coal combines with air (oxygen) to form carbon dioxide (CO2) with evolution of large amount of heat. This heat is transferred to the water in the boiler and heats it to steam. Further the outlet of boiler is connected to steam turbine.


Coolant


Water is the most commonly used coolant in such plants.

Turbine


what is turbine?

Turbines are the devices which has series of blades fitted on a drum like structure of a shaft. It can also be said that it a wheel marked with vanes on its periphery that rotates when large amount of fluid (water, air, steam) passes over the blade.

Through turbines which exchange of energy takes place. Here steam pressure energy is converted mechanical energy (rotating of shaft).


The steam from outlet of boiler enters the turbine and hit the blades. The high pressure steam expands across the blade of turbine. This action rotates the blades of turbine. This is further coupled with a generator.


Condenser


After rotating the turbine blades the steam enters the condenser. As the name suggests, the work of condenser is capable of taking away heat of the steam and changes its phase from gas (steam) to liquid form so that it could be re circulated in the boiler.


It has heat exchanger tubes on its surface through which cooled water is circulated. The steam entering the condensor gives away its heat to cooled circating water flowing in tubes and condenses to water which can be recirculated in the plant.


Generator


This is a electrical device capable of converting kinetic energy into electrical energy. It works on Faraday's law of electromagnetic induction. The generated electricity (power) is send to various power station as per requirement and finally from there it reaches your home.


Previous
Next Post »