What Is Complete Combustion?

A combustion reaction combines a fuel and oxidizer to produce heat and consume all the fuel. Reactions between a hydrocarbon and oxygen where the only byproducts are carbon dioxide and water are complete combustion reactions.

Complete combustion offers the advantage of improved efficiency. Limiting the byproducts ensures the reaction releases the maximum amount of energy. In home heating systems, the furnace transforms the fuel to provide heat. In an automobile, the internal combustion engine converts the fuel to energy that propels the vehicle down the road.

Complete combustion reduces pollutants. A propane-burning furnace set to consume approximately 4 percent propane and 96 percent air at the ideal ratio for complete combustion produces water vapor and carbon dioxide as flue gases, according to the Propane Education and Research Council. However, if the furnace is operating rich or lean, the flue gases become more dangerous. Carbon monoxide is a product of incomplete combustion. This colorless, odorless gas is deadly for humans.

While hydrocarbons combust to produce relatively harmless gases, carbon dioxide is a greenhouse gas that contributes to global warming. Petroleum fuels also contain other chemicals, such as sulfur, which add to the pollution they create. Inorganic combustion reactions do not produce all the byproducts of hydrocarbon combustion but often consume oxygen and produce heat.