ABSTRACT
The utilization of solid fuels dates back to early civili zation, and fire used for cooking and warmth was dis covered 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 fireplaces. Early industrial use of solid fuels uti lized various forms of grates with chunk wood or coal. Today, solid fuels are used in boilers (both industrial and utility), kilns, and air heaters.
