Combustion is the rapid oxidation of fuel, accompanied by heat and light. Rapid fuel oxidation results in large amount of heat and light. Air that we breathe consists of 20.9 % of O₂ and nitrogen in the air consists of 79 %, with traces of other elements. Nitrogen in the air is the temperature-reducing factor, which reduces combustion efficiency by absorbing the heat from the combustion of fuels and diluting the flue gases. Solid or liquid fuel must be changed into gases before they will burn. Most of the combustible fuels are composed of hydrocarbons, but only difference is their phase, composition and the arrangement of hydrocarbons.   more...