Liquefied petroleum gas (LPG or TNP, also propane-butane or autogas) is a mixture of liquid hydrocarbons created by the processing of oil, which in their normal state are gases, and when the pressure increases, they change to a liquid state.
In international traffic, it is denoted by the abbreviation LPG according to the English name liquified petroleum gas.
It has a very widespread use, as a source of energy in industry and the household, then as a substitute for more expensive fuels in cars, and recently it replaces various types of freon as an aerosol in various pressurized bottles, in order to reduce the harmful impact of humans on the environment, i.e. to avoid damage to the ozone layer by freon gases.
Liquefied petroleum gas consists mostly of propane C3H8 or butane C4H10, and most often it is a mixture of both gases. In smaller concentrations, liquid petroleum gas also contains some other gases, such as propylene, butylene,...
Since liquefied petroleum gas is colorless and odorless, and poses a potential hazard in the event of a leak, special additives are added to it (e.g. ethane-ethiol or tetrahydro-thiophene) which give the liquefied petroleum gas an odor and thus make it easier to detect leaks.
