How Is Coal Converted Into Other Forms of Energy?


The first step in turning coal into energy is processing. Specialized silos in coal mills called "pulverizers" crush raw coal to a smaller consistency on par with sea salt. From there, the crushed coal travels along conveyor belts at a rate of nearly 4,000 tons per hour and preheated along the way to alleviate any excess moisture.


The pulverized coal is directed into an enormous furnace, usually upward of 100 feet tall and is rapidly burned. As the coal burns, tubes along the perimeter of the furnace, which are filled with purified water, are heated to extreme temperatures. The water, as it continues to heat, circulates throughout the boiler tubes and eventually turns into steam with temperatures of around 700 degrees F and a pressure of 3,200 pounds per square inch (psi). The steam is then separated and run through pendant tubes, which superheat it to more than 1,000 degrees F. Finally, the superheated gas exits the furnace and heads toward a turbine.


The turbines that generate power are usually long, some being more than 1,000 feet, and are actually a long, wide tube lined with several successions of turbines, with each succeeding turbine having longer blades. At the end of turbine is a generator, which contains miles upon miles of copper wire for conducting electricity. Steam created from the burning of the coal in the furnace rushes through the turbine, slowly cooling as it moves along and spins the blades, which in turn activates the generator which produces electricity. When the steam reaches the end of the turbine, it is moved into the condenser, which essentially turns the steam back into water to be recycled and repeats the process once more.


With the generator spinning at an average of about 3,300 revolutions per minute (rpm) and produce up to 21,000 amps. The electricity is then flowed to an exterior distribution yard, where transformers alter the voltage in accordance with the transmission standards and ship it to its destination.