Natural Gas is found in deep reservoirs, underground and under the sea. It is piped ashore from oil rigs to a shore terminal. At this stage the Natural Gas is made up mainly of Methane but it also contains small amounts of water, dust and other hydrocarbon gases.
At the shore terminal, the gas goes through a complex system, to make the gas into a liquid. This process starts with the methane being separated from the other gasses, dust and the water. The methane gas is then cooled to minus 162 Deg C. By cooling the gas to this very cold temperature, the methane changes into a liquid state. The liquid it takes up 600 times less space. The strong tanks keep is able to keep the liquid under pressure and stops it turning back into a gas. An LNG ship can transport 125,000m3 of Liquefied Natural Gas (LNG) which equals 75,000,000m3 of regular natural gas.
LNG Carriers are some of the most expensive and specially built cargo ships sailing our seas, they are designed with the highest levels of safety and the officers and crew require special safety and operational training. Most LNG ships are built with huge, heavily insulated aluminum spherical tanks which are 40 meters in diameter, the tops of these are covered with a protective dome and can be seen above deck level.
Australia exports large volumes of LNG from the Northwest Shelf and in recent years Darwin, with many other smaller projects in the development stage.
Another gas is Liquid Petroleum Gas or LPG. It does not need as much pressure to keep it as a liquid and is easily transported in small metal cylinders such as the ones on BBQs.