Numerous processes have been developed for gas sweetening based on a variety of chemical and physical principles. These processes can be categorized by the principles used in the process to separate the acid gas and the natural gases as follows:
1. Solidbed absorption
The Sulfatreat Company: Iron Sponge, Sulfa Treat, Zinc Oxide.
Union Carbide Corporation: Molecular Shieve.
2. Chemical solvent
Monoethanol Amine (MEA), Diethanol Amine (DEA), Methyldiethanol Amine (MDEA), Diglycol Amine (DGA), Diisopropanol Amine (DIPA), Hot Potassium Carbonate, Proprietary Carbonate System.
3. Physical Solvent
Flour Daniel Corporation: Flour Flexsorb, Shell Sulfinol.
Norton Co., Chemical Products: Selexol
Lurg, Kohle & Mineraloltechnik Gmbh & Linde A.G: Rectisol.
4. Direct conversion of H2S to Sulfur
ARI Technologies: Claus, LOCAT.
Ralph M, Parsons Co: Stretford.
Exxon Chemical Co: Sulfa-check.
Institute Francais du Petrole: IFP
5. Sulfide scavenger
6. Distillation – Amine-aldehyde condensate.
7. Gas permeation
The list, although not complete, does represent many of the commonly available commercial processes. New proprietary processes are being developed. The design engineer is cautioned to consult with vendors and experts in acid gas treating before making a selection for any large plant.
