SO2 scrubbing technologies: A review

Abstract

Electricity generating units may use sulfur dioxide (SO 2) scrubbers to meet the requirements of Phase II of the Acid Rain SO 2 Reduction Program. Additionally, the use of scrubbers can reduce mercury emissions. It is timely, therefore, to review the commercially available flue gas desulfurization (FGD) technologies that have an established record of performance. Data on worldwide applications reflect that wet FGD technologies have been used at most of the installations, 522 out of 668, completed through 1998. In reviewing the SO 2 removal performance of scrubbers, data reflect that most wet limestone and lime spray drying installations appear to be capable of about 90% SO 2 removal. Advanced, state‐of‐the‐art wet scrubbers can provide removal in excess of 95%. This paper also reviews recently reported advances in SO 2 scrubbing technologies. Some of these advances have been aimed at improving the performance and cost‐effectiveness of established processes. Others, like wet ammonia FGD, have focused on developing new processes. Costs associated with limestone forced oxidation (LSFO) technology are analyzed.