Liquefied natural gas

one of the natural fuels (propane, methane, etc.) that is made into a liquid by cooling it to extremely low temperatures, LNG

Liquefied natural gas or LNG is natural gas that has been converted to liquid form for ease of storage or transport.The liquefaction process involves removal of certain components (such as dust, helium, or impurities that could cause difficulty downstream, e.g. water, and heavy hydrocarbons) and then condensed into a liquid at close to atmospheric pressure (Maximum Transport Pressure set around 25 kPa (3.6psi)) by cooling it to approximately -163 degrees Celsius. LNG is transported in specially designed cryogenic sea vessels or cryogenic road tankers; and stored in specially designed tanks. LNG is about 1/614th the volume of natural gas at standard temperature and pressure (STP), making it much more cost-efficient to transport over long distances where pipelines do not exist. Where moving natural gas by pipelines is not possible or economical, it can be transported by LNG vessels. The most common tank types are membrane (prismatic), Moss Rosenberg (spheres) or Self-Supporting Prismatic Type.
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1) Natural gas or synthetic gas having methane as its major constituent which has been changed to a liquid or semisolid. 2) Natural gas (primarily methane) that has been liquefied by reducing its temperature to -260 degrees at atmospheric pressure. (49CFR193) (DOE3)

A ship designed specifically to carry liquefied gases. (DOE5)

Natural gas converted to liquid form by cooling to a very low temperature.