Liquefied petroleum gas (LPG) is obtained by
- Liquefaction of the uncondensed gases from the fractionating column during refining of crude petroleum oil.
- The thermal cracking of heavy petroleum oil.
- The condensed gases from refineries are cooled and compressed to a liquid state. The liquefied gases are stored in cylinders.
- LPG contains colourless and odourless hydrocarbons such as propane, butane, little amounts of pentane and hexane.
- It contains small amounts of amyl mercaptan or thiophene which acts as leakage indicators due to their characteristic odour.