The natural gas used by consumers in its final state varies greatly from natural gas underground. While some processing is done at the well site, the complete process takes place at a processing plant, where the removal of impurities is required before entering the pipeline.

After leaving the gas well, the first step in production is to remove oil, water, and condensates. This can typically be done at the well site.

Next, the oil is separated from the gas with a conventional separator. This separator consists of a closed tank that separates the liquids and solids by the force of gravity. When gravity alone isn’t enough, pressure is used to “knockout” any remaining oil and a portion of the water.

Once the oil, water, and condensates have been removed, the carbon dioxide and hydrogen sulfide must be removed if present. This step is known as “sweetening” the gas, due to the scent of sulfur.

After hydrogen sulfide and carbon dioxide have been removed, the natural gas must be dehydrated. Water is removed in the form of water vapor, which can be done through absorption or adsorption.

If excess nitrogen or mercury is present, removal may be necessary. Pure natural gas is almost all methane.