21%

23%

30%

40%

provide air around burners for obtaining optimum combustion

transport and dry the coal

convert CO (formed in lower zone of furnace) into C02 at higher zone

air delivered by forced draft fan

has high heating value

retards electric precipitation

promotes complete combustion

has highly corrosive effect

keep the burner tips cool

aid in proper combustion

cause sputtering, possibly extinguish¬ing flame

clean the nozzles

prevent the bulging of flat surfaces

avoid explosion in furnace

prevent leakage of hot flue gases

support furnace freely from top