What is LNG?
Liquefied natural gas (LNG) is natural gas (predominantly methane, CH4, with some mixture of ethane, C2H6) that has been cooled down to liquid form for ease and safety of non-pressurized storage or transport. It takes up about 1/600th the volume of natural gas in the gaseous state (at standard conditions for temperature and pressure). It is odorless, colorless, non-toxic and non-corrosive. The liquefaction process involves removal of certain components, such as dust, acid gases, helium water, and heavy hydrocarbons. The natural gas is then condensed into a liquid at close to atmospheric pressure by cooling it to approximately −162 °C (−260 °F); maximum transport pressure is set at around 25 kPa (4 psi).
LNG is a product that requires processing both at the supplying and at the receiving end of the transportation chain. This is because transportation is only economically feasible when the gas is in a liquid state. Since liquefaction of natural gas reduces the volume to 1/600 of the gaseous state and therefore makes it economical for transportation by sea.
At the supply source of the transportation chain, liquefaction is done at specialized liquefaction plants, referred to as “liquefaction trains”, where undesired heavy hydrocarbons and non-hydrocarbons are removed from the natural gas before cooling the natural gas to approximately -163 °C (-260 °F) to become liquid at close to atmospheric pressure. Similarly, at the receiving end of the transportation chain, the LNG is regasified to its gaseous state before being distributed to the end-user through pipelines.
Debunking LNG myths:
Sailing with a tank full of liquefied natural gas (LNG) could sound dangerous – but is actually remarkably safe. Learn more about this and other myths about LNG in this short film.