LPG for cooking

Introduction - What is LPG?

Liquefied Petroleum Gas (LPG) is a by-product of natural gas extraction and crude oil refining. LPG is a mixture of hydrocarbon gases, the most common being butane and propane. At room temperature, LPG is a colorless and odorless non-toxic gas. Under modest pressure or cooler conditions, it transforms into a liquid state. This process leads to the reduction of the volume to 1/250 of the gaseous aggregate state and allows to store and transport LPG easily in cylinders. For safety reasons, a LPG cylinder is only filled with 80% liquid while the remaining 20% contains gaseous LPG. A typical LPG cooking system is made up of a steel cylinder filled with LPG, a pressure controller, a tube connecting the cylinder to the pressure controller and the burner, and finally the burner itself.

1 kg of LPG has an useful energy value of 20.7 MJ/kg. In comparison, air-dried firewood has an energy content of around 16 MJ/kg and charcoal of 27 - 33 MJ/kg. Depending on the type of woodfuel, charcoal production, and cook stove, between 7.3 and 29.7kg of woodfuel would be required to provide the same amount of useful cooking energy found in 1 kg of LPG. LPG is heavier than air, e.g. propane is one and a half times heavier than air, and can therefore accumulate above the ground. This may lead to LPG-’lakes’ that potentially can causes explosions. A foul smelling odorant is added to help detect leaks and thus reduce the risk of explosion.