High-Pressure H₂S Conversion and SO₂ Production over γ-Al₂O₃/Fe_χS(OH) in Liquid Sulfur

Abstract

A stainless steel autoclave was used to investigate high-pressure catalytic H 2 S conversion to sulfur in a liquidsulfur medium. Using the fundamental chemistry developed in earlier low-pressure conversion studies, the objective of this work was to investigate the use of high pressures for increasing overall H 2 S conversion to elemental sulfur. Using 1.55% H 2 S (balance N 2 ), the H 2 S scavenging activity of fresh FeO(OH) was found to increase with increasing operating pressures. Reaction of 1.55% H 2 S with 0.80% O 2 (balance N 2 ) over Fe χ S(OH) resulted in 87% H 2 S conversion to elemental sulfur at a reactor operating pressure of 6984 kPa (1000 psig). Incorporating dual-catalyst reaction conditions (γ-Al 2 O 3 /Fe χ S(OH)), 99.6% H 2 S conversion to elemental sulfur was attained using a feed gas containing 1.33% H 2 S/1.16% O 2 (balance N 2 ) and a reactor operating pressure of 1813 kPa (250 psig). It is suggested that SO 2 is generated by the iron catalyst and that H 2 S conversion occurs by the reaction of H 2 S with SO 2 , primarily over γ-Al 2 O 3 . A concurrent SO 2 kinetics investigation demonstrated very high SO 2 production activity over Fe χ S(OH) as compared to γ-Al 2 O 3 . Finally, the dual-catalyst regime proved capable of maintaining high H 2 S conversions to elemental sulfur under higher H 2 S-content feed-gas conditions. Overall, higher operating pressures proved to be effective for increasing the total H 2 S conversion to elemental sulfur.