April 17, 2018

Calculator: Combustion Air Calculations

Online Combustion Air Calculator for Air Quantity

Combustion of fuel requires the right quantity of air including excess air which is supplied by an FD Fan. The quantity of air is calculated using stoichiometry involved when air reacts with the fuel.

Fuel which is a mixture of Fixed carbon, Moisture content, Ash and Volatile material can be further broken down into simple elements such as Carbon, Sulfur, Nitrogen, Oxygen, Hydrogen, water vapor and ash particles.

Proximate and Ultimate analysis of fuel is done experimentally to determine the mass percent of various fuel elements.

You can also refer to Thermodyne’s Boiler Bible that provides you the general composition of above elements for various fuels.

Following are the basic chemical reactions involved in a combustion of air with fuel:-

C + O2               CO2  (Complete Combustion)

S + O2               SO2

2C + O2               2CO  (Incomplete Combustion)

2H2 + O2              2H2O (Moisture)


Air quantity is calculated keeping in mind the complete combustion of fuel, so for the complete combustion of fuel excess air is kept to around 20% – 50% depending upon the type of fuel, size of fuel particles and degree of mixing.

The Combustion Air Quantity Calculations calculator below helps you determine the theoretical as well as actual air requirement per Kg of fuel by providing the elemental composition of fuel and its mass faction.

See AlsoBoiler Blowdown Calculator

For boiler system related calculations Check out All Thermodyne Calculators


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