Research on desulfurization and decarbonization process of highly sour natural gas

Aiming at the desulfurizing and decarbonizing of highly sour natural gas with H₂S and CO₂ molar fraction all up to 20%, a kind of selective desulfurization solvent CT8-5 was screened via process simulation calculation combined with laboratory experiment evaluation. The CT8-5 solution has better desulfurizing capability, selectivity and higher sour gas load. The process was optimized by laboratory experiment and a series of process parameters containing gas-liquid ratio, plate number of absorber, lean solution and regeneration temperature were put forward. The results showed that on the condition of gas-liquid ratio was 200, the H₂S mass concentration in purified gas was 3.9 mg/m³ and CO₂ molar fraction was 1.86%, which could completely meet the quality requirements of commodity gas in the national standard of GB 17820-2018 Natural Gas. Facing problems of treating highly sour natural gas were discussed and some suggestions were put forward, which could provide technical ideas for the treatment of highly sour natural gas to reach the standard of GB 17820-2018.