The Selexol process uses a physical solvent to remove acid gas from streams of synthetic or natural gas. The process may be regenerated either thermally, by flashing, or by stripping gas. The Selexol process is ideally suited for the selective removal of H2S and other sulfur compounds, or for the bulk removal of CO2.
The Selexol process uses Union Carbide’s Selexol solvent, a physical solvent made of a dimethyl ether of polyethylene glycol. The Selexol solvent is chemically inert and is not subject to degradation.
Acid gas partial pressure is the key driving force for the Selexol process. Typical feed conditions range between 300 and 2000 psia with acid gas composition (CO2 + H2S) from 5% to more than 60% by volume. The product specifications achievable depend on the application and can be anywhere from ppmv up to percent levels of acid gas.
Siloxane Treatment is a completely different process:
BIMR is incorrect that Selexol has not been used for treatment of Siloxane or possible wastewater digester gas treatment which is high in H2S and CO2. He infact included the weblink (
at the end of his thread that does list Selexol in the 99% control of Siloxanes under the heading "Liquid Absorbtion" methods. Also see futher information at link below in chapter 5 for similar landfill gas treatment. However I would like more detail on it's implementation and eventual cost for treating 210 ppm H2S and 1 to 5 ppm Siloxanes.
