Natural gas is a combination of hydrocarbons primarily methane however ethane, propane and other gases such as nitrogen, helium, carbon dioxide, hydrogen sulfide, and water vapor. It is commonly referred to as natural gas liquids (NGLs). On an energy equivalent basis, NGLs generally have a greater economic value as a raw material for petrochemicals and motor gasoline than their value as components of the natural gas stream. This is a fossil fuel made from the decomposition of organic materials from the former forms of animals and plants.
NGLs can be pulled out of the ground through wells or created as a by product from crude production. Natural gas is usually in a gaseous phase (CNG) but when cooled to -260 degrees Fahrenheit it becomes a liquid (LNG). Natural gas is measured in cubic feet when referring to volume or in British Thermal Units (BTUs) when referring to heat content. One cubic foot of natural gas has approximately 1031 BTUs and a container ten feet long, ten feet wide and ten feet deep would hold one thousand cubic feet of natural gas.
In the United States approximately seventy-five percent of natural gas is pulled from underground without the presence of oil. Even without the presence of oil, there is still a need to remove solids and water before it can be used. The gas is filtered to remove the solids then dehydrated by the use of either a solid or liquid desiccant. Once it has completed this first treatment phase, it can either be sent to a compressor station and into the pipeline. When it is stored, it is usually kept in underground salt dome wells and returned to the pipeline as it is needed. NGL fractionation facilities separate mixed NGL streams into discrete NGL products to be sold individually: ethane, propane, normal butane, isobutane and natural gasoline.
Natural gas is commonly used for heating and cooking, as well as for a multiplicity of industrial purposes. Today it is also considered as an alternative fuel for automobiles. It is an environmentally friendly fuel as it is clean burning with fewer emissions of sulfur, carbon, and nitrogen than coal or oil, and it has almost no residue remaining after burning. Natural gas can be used in any vehicle with an internal combustion engine, except the vehicle must be equipped with a particular carburetor and fuel tank. However natural gas (methane) in itself is considered a greenhouse gas and during its combustion it creates the primary greenhouse gas, carbon dioxide.
On the list of alternative fuels, natural gas has a better track record as far as the environment is concerned and it is actually less expensive than the petroleum hydrocarbon based gasoline we currently use.
