Poor quality gas – natural gas containing more than 1-1/2 grains of hydrogen sulfide per 100 cubic feet.

One of the most important parts of gas processing involves the removal of sulfur and carbon dioxide. Because of the rotten smell provided by its sulfur content, this natural gas is called ‘sour gas’. This sulfur can be lethal to breathe and also very corrosive for pipelines or generation facilities. In addition, the sulfur that exists in the natural gas can be extracted and marketed on its own. Sulfur exists in natural gas as hydrogen sulfide (H2S), and the gas is usually considered sour if the hydrogen sulfide content exceeds 5.7 milligrams of H2S per cubic meter of natural gas. The process for removing hydrogen sulfide from sour gas is commonly referred to as sweetening the gas