Combustion efficiency

Theoretically complete combustion is obtained by stoichiometric amount of air and POC should not contain CO. But in actual combustion of any fuel does not occur with just stoichiometric amount of air. Excess air is required. Excess air depends on type of fuel. Normally solid fuels require more excess air than liquid fuels and gaseous fuels. Gaseous fuels require least amount of excess air.

Mixing of fuel and air is important simply because 1 mole of oxygen is accompanied by 3.76 moles of . In an air + fuel mixture, statistically the probability of finding nitrogen in the neighborhood of carbon is more than oxygen.

Thus mixing determines combustion efficiency, i.e. the ability of a device (used for mixing of fuel and air) to convert potential energy of fuel into thermal energy.