Optimal Combustion Processes - Fuel vs. Excess Air

Reference table showing typical excess air percentages for various fuel types in combustion processes. Excess air is the amount of air supplied beyond the theoretical stoichiometric requirement needed to completely burn fuel. Power plant boilers typically run 10-20% excess air, while natural gas-fired boilers may run as low as 5% and gas turbines run very lean with up to 300% excess air.

Fuel Type	Excess Air (%)
Anthracite	40
Coke oven gas	5 - 10
Natural Gas	5 - 10
Coal, pulverized	15 - 20
Coal, stoker	20 - 30
Oil (No. 2 and No. 6)	10 - 20
Semi anthracite, hand firing	70 - 100
Semi anthracite, with stoker	40 - 70
Semi anthracite, with traveling grate	30 - 60