Liquefied petroleum gas(LPG),light hydrocarbons in refinery gas and natural gas are gas state in ambient temperature and normal pressure and can become liquid state in the condition of pressurization and drop in temperature. Its main components are propane and butane. LPG is a flammable material. In case the air content reaches a certain concentration, it is explode in the case of fire.
LPG is mainly obtained by separation from condensate field gas. The main components are as follows (%): 1-3% of ethane, 30 to 40 % of propane, 55 to 65% of butane, containing not more than 3% hydrocarbons of 5 or more carbon atoms. It is mainly used as petrochemical raw material for hydrocarbon cracking for preparation of ethylene or synthesis gas by steam conversion as industrial, commercial and internal combustion engine fuel. The main indicators of quality control are evaporation residues and the sulfur content, etc..