Feasibility study of a sulfur recovery unit containing mercaptans in lean acid gas feed

Acid Gas Enrichment (AGE) and Tail Gas Treatment (TGT) are conventional processes to enhance recovery of sulfur in sulfur recovery plants. Depending on the presence of organic sulfur components such as mercaptans and carbonyl sulfide, two configurations for AGE off-gas may be considered. Optionally, AGE off-gas can be sent to incinerator or fed to TGT section. In this paper, these two cases are investigated in terms of technical and economical points of view. The achieved results show that although routing AGE off-gas to TGT section will increase the size and cost of TGT equipment, it can reduce the environmental pollutants.