Liquefied Natural Gas (LNG)

liquefied natural gas LNG natural gas primarily methane that has been liquefied for ease of storing and transporting Liquefied natural gas LNG is 600 times smaller than natural gas when the latter is in its gaseous form and it can be easily shipped overseas LNG is produced by cooling natural gas below its boiling point 162 C 259 F and is stored in doublewalled cryogenic containers at or slightly above atmospheric pressure It can be converted back to its gaseous form by simply raising the temperature Natural gas is a hydrocarbon mixture consisting primarily of saturated light paraffins such as methane and ethane both of which are gaseous under atmospheric conditions The mixture also may contain other hydrocarbons such as propane butane pentane and hexane In natural gas reservoirs even the heavier hydrocarbons occur for the most part in gaseous form because of the higher pressures They usually liquefy at the surface at atmospheric pressure and are produced separately as natural gas liquids NGLs either in field separators or in gas processing plants Once separated from the gas stream the NGLs can be further separated into fractions ranging from the heaviest condensates hexanes pentanes and butanes through liquefied petroleum gas LPG essentially butane and propane to ethane This source of light hydrocarbons is especially prominent in the United States where natural gas processing provides a major portion of the ethane feedstock for olefin manufacture and the LPG for heating and commercial purposes