DETERMINATION OF AIR SUPPLIED

1 Percentage of Carbon by Mass in Fuel and Volumetric Analysis is Known

We know that 1 kg of flue gas contains

  kg of CO and  kg of CO₂

Amount of carbon in  kg of 

Amount of carbon in  kg of 

Total mass of carbon in 1 kg of flue gas  kg

Let C = mass fraction of carbon in fuel and there is no nitrogen in fuel.

m_g = mass of flue gases formed per kg of fuel burned.

Then, 

Now, nitrogen in 1 kg of air supplied = 0.77 kg

N₂ in 1 kg of flue gas = 

∴ Air supplied per kg of flue gas = 

Mass of air supplied per kg of fuel = mass of air supplied per kg of flue gas × mass of flue gases formed per kg of fuel.

2 Excess Air Supplied

The oxygen carried in the flue gases comes only from the air supplied for the combustion of fuel. In addition, the oxygen necessary to convert CO to CO₂ should be taken into account in calculating the excess air supplied.

CO in 1 kg of flue gas = 

O₂ in 1 kg of flue gas = 

O₂ required for burning  kg of CO to CO₂ = 

Excess O₂ available per kg of flue gas formed 

Excess O₂ supplied per kg of fuel = Excess O₂ per kg of flue gas × m_g

Excess air supplied per kg of fuel