Liquefied (Liquid) Petroleum Gas (LPG or LP gas), also referred to as simply Propane or Butane, are flammable mixtures of hydrocarbon gases used as fuel in heating appliances, cooking equipment, and vehicles.
It is increasingly used as an aerosol propellant and a refrigerant replacing Chlorofluorocarbones. It is in an effort to reduce damage to the Ozone layer. When specifically used as a vehicle fuel it is often referred to as autogas.
Varieties of LPG bought and sold include mixes that are mostly Propane mostly Butane. It is commonly, mixes including both Propane, while in summer, they contain more Butane.
Propylene, Butylenes and various other hydrocarbones are usually also present in small concentrations. HD–5 limits the amount of propylene that can be placed in LPG to 5%, and utilized as an autogas specification. A powerful odorant, ethanethiol, is added so that leaks can be detected easily.
LPG is prepared by refining petroleum or “wet” natural gas. It is almost entirely derived from fossil fuel sources, being manufactured during the refining of petroleum (crude oil). LPG extracted from petroleum or natural gas streams as they emerge from the ground.
It currently provides about 3% of all energy consumed. Liquefied petroleum gas burns relatively cleanly with no soot and very few sulfur emissions. As it is a gas, it does not pose ground or water pollution hazards, but it can cause air pollution. LPG has a typical specific caloric value of 46.1 MJ/kg compared with 42.5 MJ/kg. for fuel oil and 43.5 MJ/kg for premium grade petrol (Gasoline). However, its energy density per volume unit of 26 MJ/L is lower than either that of petrol or fuel oil, as it is relative density is lower (about 0.5 – 0.58 Kg/L, compare to 0.71 – 0.77 Kg/L for gasoline. As its boiling point is below room temperature, LPG will evaporate quickly at normal temperature and pressures. It is usually supplied in pressurized vessels.