Natural gas is a combustible mixture of hydrocarbon gases. Considered a fossil fuel, natural gas is formed in the earth when gases are released from decaying organisms and trapped under pressure over millions of years.
Natural gas is mostly compiled of methane (up to 90%) with the remainder sometimes consisting of ethane, propane, butane, carbon dioxide, oxygen, nitrogen, hydrogen sulphide and trace amounts of rare gases.
Natural gas is odourless, colourless, shapeless, non-corrosive and is lighter than air. When it is refined and processed into almost pure methane it has no smell, so a unique smell has to be added. This can resemble the smell of a rotten egg. This smell is purely added to allow detection of gas escapes from pipes more easily.
Natural gas is considered ‘dry’ when it has been processed into pure methane, and `wet` when the other hydrocarbons are present.
`Wet` natural gas extracted from crude oil deposits is often refined into LPG (Liquefied Petroleum Gas). The gas is chilled to -161ºC so that it becomes a liquid. LNG occupies about 1/600 the volume of methane when it is in a gaseous form.
This allows it to be exported in purpose-built tanker ships for delivery anywhere in the world. This synthesised gas can be used as fuel for heating appliances and vehicles. More often, the gas is used as a propellant in aerosol and refrigeration which replaces chlorofluorocarbons.
What is natural gas used for?
Gas is used to generate electricity and to power appliances such as heaters and stoves.
It is also important in many industrial processes, including fertiliser production, glass, steel, plastics, paint, fabrics and in the manufacture of many other products.
Technologies developed in the 1940’s allowed for the compressing of natural gas into a liquid. This technique allowed for easier storage and transport of the gas.
A worldwide market quickly grew to supply countries that did not have natural gas reserves to allow them to supply energy for their domestic market.
Australia is a world leader in LNG innovation. The world`s first coal seam gas-to-LNG projects are being developed in Queensland.
The major sectors that consume natural gas include manufacturing, electricity generation, mining and the residential market (used for water heating, cooking and heating the home). LNG can be used as transportation fuel for heavy vehicles like trucks.