Specification :

Liquefied Petroleum Gas (LPG) refers to mixtures of petroleum gases released during the production of crude oil and natural gas and during the refining of crude oil. The quantity of automotive LPG produced in refineries is generally very small (approximately 1-5%).
Mixtures of propane and butane are normally used for automotive LPG. Butane predominantly consists of hydrocarbon streams containing four carbon atoms, mainly n- and Iso - butanes (C4H10), whilst propane mainly consists of hydrocarbon streams containing three carbon atoms (C3H8). Automotive LPG often contains small quantities of other components such as n-butane, Iso-butane, pentane, ethane, propene and butane.