Liquefaction

The natural gas liquefaction process consists in cooling the gas down to a temperature of -160 degrees Celsius, at normal atmospheric pressure. This process makes the gas change its state to liquid, reducing its volume by a factor of 600, thus enabling transport of larger quantities of energy all over the world.

Contrary to compressed natural gas coming directly by pipeline from production areas (e.g. Algeria and Russia), LNG is almost pure methane, since its other components are removed in the liquefaction process :

• Carbon dioxide must be removed beforehand because it would damage the liquefaction units by solidifying inside. It is generally considered as waste.
• Hydrocarbons that are heavier than methane (ethane, butane, propane) are recovered and sold as raw material or as fuel to the petrochemical industry.
• Helium is a by-product of substantial commercial value.