LPG – liquefied petroleum gas – is an energy source that is in wide use around the world. It is produced in two ways: 60 per cent is extracted from the earth in natural gas fields where it exists in ready form together with methane, and 40 per cent comes from refining crude oil, a process that also yields mineral spirits and diesel fuels as by-products. Long ago, LPG was burned away in the refining process as an undesirable by-product, but later it was found that it could be stored as well.
Although LPG is indirectly related to natural gas production and oil refining, this energy source with its clear advantages is now established and gaining increasing popularity.
A number of other gases and liquids can also be extracted during natural gas and oil refining, of which LPG accounts for about 5 per cent. Before natural gas and petroleum can be transported or used, the slightly heavier gases must be removed.
Refining crude oil is an even more complicated process, which consists of several stages. Atmospheric distillation, reforming and cracking are just a few of the stages where LPG is separated from oil. This method of production is also unavoidable as the liquid gases (propane and butane) are trapped within the crude oil. The “natural gases” with their strong bonds must be removed so that the crude oil could be transported in pipes and in tankers.
In the refining of crude oil, LPG is one of the first products produced before the heavier fuels such as petrol, diesel and fuel oil are tackled. Around 5% of an ordinary barrel of crude oil is refined into LPG, although potentially 40 per cent of the barrel could be converted to LPG.