Question

How does a coal-fired power plant use the energy in coal to produce electricity?

Answer 1

Answer:

Answer is in explanation

Explanation:

A coal-fired power plant also known as steam power plant or thermal power plant is a generating station that converts heat energy of coal combustion into electrical energy. In a coal-fired power plant, steam coal, also known as thermal coal serves as the boiler's fuel.

Coal is collected, transported by road or rail to the power plant and stored in coal storage plant. Excess coal is stored in case of coal shortages, failure of transportation system, emergency outages or high electricity demand. From the coal storage plant, coal is fed to a crusher (or pulverizer or mill) through a conveyor. Inside the crusher, the coal is pulverized (crushed or milled) into fine powder. This increases the surface area and allows it to burn more quickly without using large quantity of hot air. The powdery coal is blown into the combustion chamber of a boiler then mixed with hot air where it is burnt at high temperature. After complete combustion of coal, ash produced is removed and  delivered to ash storage plant for disposal. The combustion reaction inside the boiler produces the heat energy needed to boil water in the pipes into steam at high temperature and pressure. The steam produced in the boiler is wet and is passed through a super-heater  where it is dried and super-heated.

The super-heated steam is passed into a steam turbine (containing thousands of propeller-like blades) through main valve. The heat energy from the steam is then converted to mechanical energy. The steam causes the turbine shaft to rotate at high speed by pushing the blades of the turbine. The rotating turbine drives the shaft of a generator mounted at one end of the turbine. Mechanical energy from the turbine is converted to electrical energy by the generator. When this generator is rapidly rotated in a strong magnetic field, electricity is generated. The electricity generated is stepped up into higher voltages and transmitted to power stations where it is stepped down into lower voltages for industrial and domestic usage. Steam exhausted  from the turbine is condensed by a condenser (natural or artificial). The condensed water from the condenser is fed back to the boiler to be heated once again as the cycle continues. This helps in improving the overall efficiency of the plant.