It consists of hydrocarbons, mainly propane, butane and other alkanes or olefins. The combination percentage of propane and butane exceeds 60%, otherwise it cannot be called liquefied petroleum gas;
This hydrocarbon gas is gaseous at normal temperature and pressure, and can exist in liquid at normal temperature after pressurization, so it is called liquefied gas;
Hydrocarbons with more than five carbons belong to gasoline and diesel oil, that is, they are liquid at normal temperature and pressure; C 1, C2, that is, methane, ethane and ethylene must be pressurized and frozen to become liquid.