LPG stands for liquefied petroleum gas and is a liquefied form of petroleum gas, or liquefied gas in general. It can be liquefied under light pressure and is a by-product of the refining process during distillation. It returns to its gaseous state when depressurised.
The boiling temperatures at atmospheric pressure are between -0.5 ºC (n-butane) and -61 ºC (n-butylene).
This gas is known in the mineral oil industry as LPG, which (under normal conditions) means the gaseous hydrocarbons propane and butane, and their gaseous olefins such as propylene and butylene, and combinations thereof.
Propane and butane are growing in importance as combustible gases in domestic, commercial and industrial applications, whilst the corresponding gaseous olefins are used preferably in the petrochemical industry.
Transport (see Liquefied gas pump) is accomplished in pressurised bottles for small quantities, and in pressure tank cars or trucks for larger quantities.