So, in the process of combustion, we are dealing with chemistry. Thus, it involves knowledge
of the composition of the coal, its physical condition, its behavior under various
conditions of temperature, moisture, etc. Actually, the combustion of coal is a very complex
process requiring a good knowledge of both physics and chemistry. In a large plant it
involves a major problem in materials handling – fuel, ashes, air and flue gas. Remember,
in burning coal, you have to supply about 17 pounds of air for each pound of coal used.