Improved oxidation process increases sulfur recovery with Claus unit

摘要

Since its development in 1936, the "modified Claus" technology has been the preferred process used by refineries and gas processing plants for the recovery of sulfur from acid-gas streams. Modern sulfur plants include a burner and a thermal reactor tied to a waste-heat exchanger as the first and second process units followed by a catalytic reaction section consisting of two or more catalytic converters. If sulfur recovery higher than 98% is required to meet the low-sulfur emission standards set by legislation, a tail-gas cleanup process must be included in the design of the sulfur recovery unit (SRU). The modified Claus process, however, has a number of operating challenges that are associated with the reactions and occur in the burner and thermal reactor. Some of these problems are: sustainable flame stability, operational reliability, minimum acid-gas concentration, strict control of the acid gas to air ratio, soot formation, catalyst fouling, and the formation of undesired byproducts such as carbonyl sulfide (COS) and carbon disulfide (CS2).