LNG Explained

LNG, or Liquefied Natural Gas, is simply natural gas in a liquid form. It is the same natural gas that millions of Australian homeowners and businesses use every day.  Put simply, LNG is Natural Gas Made Portable™.

 
LNG PlantNatural gas is processed into LNG by cooling it to −161°C, at which point it becomes a liquid. This reduces the volume of the natural gas by a factor of more than 600 times as it goes from it's gaseous state to liquid.


The liquefaction process also involves the removal of certain impurities, including dust, acid gases, helium, water and heavy hydrocarbons.  It is important to remove all components that would freeze during the liquefaction process.
 

This reduced volume facilitates efficient transport by sea or road. Specially designed cryogenic ships or cryogenic tanker trucks are used for its transport. Once at its destination, LNG is unloaded into storage facilities, where it is stored as a liquid until use.  Storage pressure in these tanks is very low, at less than 10 Bar. 


LNG Plant TASThe storage insulation will not keep LNG cold enough by itself. Heat leakage will warm and vapourise the LNG. Industry practice is to store LNG as a boiling cryogen. That is, the liquid is stored at its boiling point for the pressure at which it is stored (atmospheric pressure). As the vapour boils off, heat for the phase change cools the remaining liquid. As the insulation is very efficient, only a relatively small amount of boil off is necessary to maintain temperature. This phenomenon is known as auto-refrigeration.  The boil-off gas is used as a fuel source in the facility or on the tanker transporting it.


When required for use, LNG is warmed back to natural gas, a process known as regasification. This regasification is accomplished using a process involving heat exchangers. The natural gas can be used on-site, sent through pipelines for distribution to homes and businesses or used as a fuel for large vehicles.


LNG, which is predominantly Methane, is an odourless, non-toxic and non-corrosive.  If spilled, the LNG evaporates quickly and disperses, leaving no residue. There is no environmental cleanup needed for LNG spills on water or land.