Heat of Combustion

Definition - What does Heat of Combustion mean?

Heat of Combustion is the heat released under standard conditions during the combustion process. In order to have a complete combustion, the combustion process takes place in presence of adequate oxygen. The burning of hydrocarbon, for example, in the presence of oxygen to produce carbon dioxide and water is the complete combustion process. It can also be taken as the heat content of the fuel.

Petropedia explains Heat of Combustion

The heat of combustion can be measured as:

Energy per mass of the fuel
Energy per mole of the fuel
Energy per volume of the fuel

The bomb calorimeter is used to measure the amount of heat produced during the combustion process. For a reaction the difference between the heat of formation of reactants and products is also the measure of heat of combustion. The heat of combustion of natural gas is 13 Kcal/g and for lignite coal it is 4.4 Kcal/g. The presence of moisture in the petroleum fuel is also vital as it brings down the heat of combustion because some amount of heat is required to first take the moisture off. The higher the enthalpy or heat of combustion of the petroleum fuel, the better will be its market value, i.e., it will fetch higher price in the market during trading.