Coal Burning : Effect of excess air or Less air

Coal Burning : Effect of excess air or Less air

Quantity of air required in burning of the cole is most important. By this we can save the energy losses in coal burning.

As in manufacturing of sponge iron coal is used in different size, and it is required that ever part of the coal should come in air contact for proper combustion. (In case of burning of un-burnt coal in ABC.)  

CASE - I (Air is Less than required)

•  In this case some part of coal goes out with out burning which is a loss of potential energy, which is known as un-burnt carbon loss. 
• in the normal combustion reaction Carbon and Oxygen combine to form Carbon dioxide giving out heat. Actually this takes place in two stages , first is the formation of Carbon monoxide and then the Carbon monoxide reacts to form Carbon-dioxide. If the air is less the second stage does not take place, and Carbon monoxide is formed. This means a part of the potential energy of the coal is not released. This is an energy loss.

CASE - II (Air is More than required)

If the air supplied for combustion is more than required, the air that is in excess of the combustion requirement does not contribute to the combustion process , but takes away a part of the combustion heat then goes up the stack as waste heat. This is an energy loss. This is called the Dry Gas loss.