ABSTRACT
The utilization of solid fuels dates back to early civilization and the discovery of re, used for cooking and warmth long before liquid or gaseous fuels were in use. Early utilization of solid fuels in the last few centuries started with cut wood or chunk coal burned in stoves and replaces. Early industrial use of solid fuels utilized various forms of grates with chunk wood or coal. Today, solid fuels are used in boilers (both industrial and utility), kilns, and air heaters.
