What is fly ash and how is it generated?

Fly ash is a byproduct generated from the combustion of coal in power plants and industrial boilers. It is produced when fine particles of ash are carried away from the combustion chamber by the flow of flue gases. The very high temperatures that occur during combustion result in the formation of these particles, which are then cooled and solidified as they travel through the exhaust system. Since fly ash is lightweight and composed of fine particles, it can remain suspended in the flue gas and is typically captured by emission control systems before the gases are released into the atmosphere.

This specific generation process distinguishes fly ash from other types of ash produced in combustion systems, such as bottom ash, which settles at the bottom of the furnace, and products that accumulate in ash ponds. Understanding this process is essential for managing emissions and ensuring efficient operation of combustion systems, making the identification of fly ash as that which is carried out of the furnace with the flue gas flow critical for power engineering students.