Liquefied Petroleum Gas, more commonly known as LPG, is hydrocarbon fuel, lighter than petroleum, occurring naturally in oil and gas fields or extracted in the oil refining process. These high quality gases are suitable for compact storage and transport in liquid form, in pressurized bulk vessels or cylinders.
LPG is the term widely used to describe a family of light hydrocarbons called “gas liquids”. The most prominent members of this family are propane (C3H8) and butane (C4H10). Other members of the LPG family are ethane and pentane. It is the unique character of LPG that makes it such popular and widely used fuel. LPG at normal temperature and pressure is a gas and changes to liquid when subjected to modest pressure or cooling. In liquid form, the tank pressure is about twice the pressure in a normal truck tire. The reason LPG is liquefied is to make it easy and efficient to transport and store. One unit of liquid has the same energy content as 270 units of gas. Thus, LPG has density for storage and transportation, yet all the benefits of a clean vaporous fuel when used at the burner tip or engine. For standard heating and cooking purposes, LPG usually consists of a mixture of propane and butane. Propane starts vaporizing above -45°C, so it is more versatile for general use. Butane starts vaporizing above -2°C and requires a propane/butane mixture in cold environments, as it will not vaporize as readily as propane.