Novel processes for lean acid gas utilization for sulfur production with high efficiency

Abstract Claus process has a high efficiency for H2S-rich acid gas, but when H2S content is below 50%, methane co-combustion is required to sustain combustion that enhances the operating cost. In this study, two processes are designed that initiate with sulfur combustion. In first process, sulfur combustion generates SO2 that is mixed with acid gas in catalytic reactors for sulfur recovery. In second process, SO2 from sulfur combustion is mixed with acid gas in the furnace and in the catalytic units for sulfur production. For feeds with 10–65% H2S, the optimized sulfur recovery efficiencies varied within 98.3–98.5% for the first process, within 96.8–98.6% for the second process, and within 96–98.2% for the Claus process. The heat recovery in the waste heat boiler remained low for the first process as compared to the Claus process. The suggested process reduces CO and SO2 emissions from sulfur recovery units for lean acid gas feed.