A thermal power plant converts the heat energy of fuel (usually coal, natural gas, or oil) into electrical energy. Most coal-fired plants operate on the Rankine Cycle, where water is repeatedly converted into steam and back into water.
Basic Working Principle
The overall process is:
Fuel → Heat → Steam → Turbine Rotation → Generator → Electricity
Step-by-Step Working of a Thermal Power Plant
1. Coal Handling Plant (CHP)
Coal is received by train or truck and stored in the coal yard. Equipment such as stackers, reclaimers, crushers, and conveyors transport the coal to the boiler.
2. Pulverizing Mill
Coal is crushed into a fine powder in coal mills. Fine coal burns more efficiently.
3. Boiler and Furnace
The pulverized coal is burned in the furnace. Heat converts water flowing through boiler tubes into high-pressure, high-temperature steam.
4. Superheater
The steam is heated further to remove moisture and increase its temperature, improving turbine efficiency.
5. Steam Turbine
The superheated steam expands through the turbine blades, causing the turbine shaft to rotate.
6. Generator
The turbine shaft is coupled to a generator, which converts mechanical energy into electrical energy through electromagnetic induction.
7. Transformer
The generated voltage is increased by a transformer so the electricity can be transmitted efficiently over long distances.
8. Condenser
After passing through the turbine, the exhaust steam is cooled and condensed back into water under vacuum conditions.
9. Cooling Tower
Warm cooling water from the condenser is cooled and recirculated.
10. Boiler Feed Pump
The condensed water is pumped back to the boiler, completing the cycle.
