Natural gas is used in all sectors of Australian industry, in particular in the chemical, rubber, paper, metal, milk, plastics and vehicle industries. Gas is used as a feedstock because of its chemical properties or because it can cheaply and rapidly heat to very high temperatures.
Natural gas is made up of two main gases, methane and ethane, but there are a number of other useful gases including propane and butane. Products manufactured with different combinations of the chemicals in gas include soap and cosmetics, household detergents, car components and pharmaceuticals.
Chemicals made from natural gas
Methane from natural gas is made into methanol and this is mixed with other chemicals to make four main chemicals: ammonium nitrate, sodium cyanide, methanol and peroxide.
|Chemical||Products and uses|
|ammonium nitrate||fertilisers, refrigerants, explosives, soft drinks and medical applications|
|sodium cyanide||gold extraction and processing|
|methanol||building products, paints and resins, pigments and dyes, carpeting, adhesives, agricultural chemicals, biodiesel and agents for the treatment of sewage and waste water|
|peroxide||cleaning products, paper pulp, mining and food and textile manufacturing|
Ethane is made into polyethylene and ethylene oxide which are components of a variety of everyday items.
|Chemical||Products and uses|
|bags and films for food storage, retailing and wrapping|
|agricultural and irrigation piping, water tanks|
|films and wrapping for animal fodder and grain storage|
|rigid containers for food storage|
|industrial reticulation applications in mining and gas production and the commercial use of water|
|gathering lines in the unconventional gas sector|
|Ethylene oxide||polyols for foam insulation for appliances such as refrigerators and freezers, shoe soles, adhesives, automotive applications, textiles, bedding and furniture.|
|glycol for antifreeze, resins and polyester fibre|
|surface wetters for agricultural applications|
Natural gas has no real alternative as a feedstock in making the chemicals that are used in the industries described above. They often require gas to be supplied continuously for efficient production processes.
High temperature uses of gas
Natural gas can heat rapidly and efficiently and it has low emissions compared to other hydrocarbon fuels and grid electricity. That makes it the fuel of choice for industrial applications requiring high temperatures or high-pressure steam.
One key application is in the high-temperature furnaces required to hygienically dispose of medical waste and associated biohazards. These furnaces require consistent and reliable delivery of high temperatures and this is achieved by using gas.
Consistent high temperatures are also required in the commercial production of bricks in Australia. Alternative energy sources to heat brick-baking kilns can be problematic – for example coal quality varies and this results in inconsistent heating and it is much more expensive to use electricity to achieve consistent very high temperatures.
Other industries using gas to manufacture products include those making cement, pulp and paper, glass, and food and beverages, and those involved in refining alumina and non-ferrous metals. These include almost every product used in construction – windows, plasterboard, aluminium frames, fencing and screens, concrete and more.
On-site electricity generation
Industries that are remote from the electricity grid, such as mining, often use gas for on-site electricity generation. Natural gas can be delivered to the site via a transmission pipeline. Using gas often replaces more expensive diesel fuel which has higher carbon emissions and usually has to be transported by road, increasing pollution and the risk of accidents.
Compressed natural gas (CNG) is natural gas that has been compressed for use in vehicles. In Australia, CNG is often used in city and suburban bus fleets and some intercity heavy road transport uses it as well. CNG has a number of safety advantages over petrol: it burns efficiently and has lower emissions and it can be retro-fitted to existing vehicles. As the refuelling network grows, the use of CNG is expected to increase. One key expected use of CNG is at remote sites, such as mines, that already have a gas supply. Such use would eliminate the need to transport diesel across vast distances.