LPG, or liquefied petroleum gas, is a mixture of hydrocarbons with gaseous qualities at atmospheric pressure and which liquefies at an environmental temperature and not very high pressure. LPG derives from the elaboration of natural gas and the refining of crude oil; it is also sold on the market as a blend (propane/butane) and as commercial propane and butane.
LPG, as a blend of propane and butane, accounts for up to 5% of natural gas: it is normally separated immediately after extraction of crude gas, which is essentially made up of methane. The LPG that derives from the refining of oil is obtained from the first distillation of crude and from the reforming process, while lower quantities are obtained from conversion processes (catalytic cracking, hydrocracking, visbreaking).
Like natural gas, LPG is an energy source with a low environmental impact which is mainly used in the residential and transport sectors. It is an “eco-compatible” fuel in that the presence of polluting substances and the greenhouse gases emitted into the atmosphere during combustion – both in residential and transport uses – is markedly inferior to that of traditional liquid fuels. In liquid form, LPG is easy to store, handle and transport in pressurised tanks, by rail or road, and made available for use cheaply at domestic and industrial sites or from the fuelling of vehicles.
In the residential sector, these characteristics make it possible to store significant quantities of energy in small tanks, making the fuel easily available to users, also in places where the logistical or geographic characteristics make it difficult to supply other means of meeting energy requirements. In the transport sector, storage, in a liquid form at low pressure, in the small tanks of cars and vans, allows drivers to enjoy the same level of autonomy as for traditional vehicles, with very limited additional weight.