Gas refining usually involves the use of several integrated unit processes to remove: (1) oil, (2) water, (3) elements such as sulfur, helium, and carbon dioxide, and (4) natural gas liquids. In addition, it is often necessary to install scrubbers and heaters at or near the wellhead that serve primarily to remove sand and other large-particle impurities. The heaters ensure that the temperature of the natural gas does not drop too low and form a hydrate with the water vapor content of the gas stream.
Many chemical processes are available for processing or refining natural gas. However, there are many variables in the choice of process of the choice of refining sequence that dictate the choice of process or processes to be employed. In this choice, several factors must be considered: