LPG are the light hydrocarbons fraction of the paraffin series, derived from refinery processes, crude oil stabilisation plants and natural gas processing plants comprising propane, butane and butylenes or a combination of them.
LPG may be also called liquefied refinery gases.
LPG have no natural odor
As light hydrocarbons of the paraffin series, LPG are derived solely from the distillation of crude oil.
LPG can be liquefied under low pressure (5-10 atmospheres).
In the liquid state and at a temperature of 38 °C, LPG have a relative vapor pressure less than or equal to 24.5 bars.
Large quantities of LPG are now available as a by-products from the gas and petroleum industries.
LPG are obtained as light ends from the fractionation of the crude oil.
LPG have good caloric value, to be used for transportation fuel as well as cooking fuel.
Since LPG have no natural odor, a distinctive odorant is added so that it will be noticeable should a leak occur.
Because of the low boiling point (−44 to 0°C) and high vapor pressure of these gases, their handling as liquids in pressure cylinders is necessary.
Then LPG transportation is easy with steel pressurized bottles to be used in remote areas as domestic fuel.
LPG are often employed as fuel for tractors, trucks, buses.
Another factor of importance in internal combustion engines is that LPG leave little or no engine deposit in the cylinders when they bum.
The exhausted gas from engine combustion are also pretty clean compared with gasoline and diesel so that LPG can be used in industrial applications for handling and forklift trucks.
Owing to demand from industry for butane derivations, LPG sold as fuel are made up largely of propane.