A novel process to recover sulfur in aqueous phase under ambient condition

Abstract

Sulfur recovery is an important industrial process for fossil fuel clean consumption, in which H 2 S is firstly separated from the gas stream from the hydrodesulfurization process or gasified gas of coal or biomass. Meanwhile, almost equivalent half amount of SO 2 is produced from the boiler on-site due to the power and steam generation or the fluid catalytic cracking process in a refinery. Currently, H 2 S is converted into elemental sulfur using Claus process, which is being used worldwide, and SO 2 is removed from the flue gas using lime or lime water. The two sulfur removal technologies require lots of capital investment and operating cost. Here, we have developed a novel process for SO 2 in flue gas to react with H 2 S from the gasified gas stream, to convert them elemental sulfur by washing the flue gas and H 2 S with liquid catalyst containing water stream, the sulfur in SO 2 and H 2 S is converted into elemental sulfur and floated in the washed solution pool, which can be filtered out. Here, the pilot test results of the aqueous phase ambient temperature sulfur recovery process has been described and analyzed. The system converted more than 1000 ppm of H 2 S and 500-600 ppm of SO 2 in the flue gas into elemental sulfur in aqueous phase at temperature below 100 °C. The flue gas was washed with our acid aqueous media, and the sulfur is formed in the aqueous acid catalyst solution and was filtered out. The sulfur powder has the same laser Raman spectra with the Claus process, with the main structure as S 8 with high purity.