Nature and Chemistry of Hydrocarbon Combustion

Hydrocarbon materials must first be in a vapor condition before combustion processes can occur. For any gaseous material this is an inherent property. Liquids however must have significant vapor emissions in order for flammable concentrations to be present for combustion processes to occur. Therefore hydrocarbon liquid releases are nominally less dangerous than a gas release. 

When an ignition source is brought into contact with a flammable gas or mixture of gases, a combustion chemical reaction will occur at the point of introduction provided an oxidizer is present, normally oxygen. The combustion components are commonly referred to as a simple fire triangle  

A more scientific representation is a fire tetrahedron with the combustion chemical reaction considered as a fourth parameter or side of the tetrahedron. 

Combustion will occur which travels from the point of origin throughout the body of the gas and air mixture. Combustion continues until the fuel is exhausted, if sufficient air (i.e., oxygen) is available or until a suppression mechanism interrupts the process. 

The basic equation for the chemical reaction of hydrocarbon molecules in ideal combustion is provided by the following  

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