Raw coal is crushed into smaller pieces to increase surface area for better combustion and processed to remove impurities such as ash and sulfur.
Step 2: Combustion in the Boiler
Pulverized coal is then fed into a boiler, where it is burned with preheated air. The coal's chemical energy is released as heat energy, which converts water in the boiler into steam at very high pressure.
Step 3: Superheating and Reheating
The steam leaving the boiler is known as primary steam. To increase efficiency, the primary steam is superheated in secondary superheaters by exposing it to even higher temperatures. Some power plants also employ reheaters, where the steam is reheated after it expands through the first stage of the turbine (known as reheating).
Step 4: Steam Turbine
The high-pressure and high-temperature steam from the boiler or reheater enters a steam turbine, a multi-staged device consisting of rows of rotating blades. As the steam passes through the turbine blades, it loses energy and imparts force on the blades, causing them to rotate. The rotation of the turbine is what ultimately generates electricity.
Step 5: Condenser and Cooling
After the steam passes through the turbine blades, it enters the condenser, a heat exchanger where the steam is condensed back into water with the help of a cooling medium, such as river water or cooling towers. The condensed water is then pumped back to the boiler to repeat the cycle.
Step 6: Generator
The rotating shaft of the turbine is connected to a generator, which converts mechanical energy into electrical energy through electromagnetic induction. As the generator rotates, it induces a flow of electrons in the surrounding electrical conductors.
Step 7: Transmission
The electrical power generated at the power plant is usually transmitted over high-voltage transmission lines to various distribution centres, which then deliver the power to homes, industries, and businesses through local distribution networks.
