Natural gas, refinery gas, and coal gas contain acid gases such as hydrogen sulfide (H 2 S) and carbon dioxide that must be removed from the gas stream due to the toxicity of H 2 S and to prevent corrosion to piping and production facil- ity caused by the acid gases. In this article, current technolo- gies for the acid gas removal are selected and reviewed. The review includes absorption, adsorption, conversion of H 2 S into elemental sulfur, and membrane reactor for H 2 S decom- position and desulfurization. Recently, hollow fiber mem- brane contactor has been in the limelight of research in H 2 S absorption from gaseous mixture due to its potential to over- come problems such as foaming and loading. Recent trends on Claus tail gas cleanup technologies are highlighted due to the recent progress in membrane technology. The article also suggests current research on the acid gas removal technol- ogy using catalytic membrane reactor. The interest on find- ing suitable active component and support and studying the membrane structure for enhanced removal of acid gases is likely to be rekindled in the near future.

Present technologies for hydrogen sulfide removal from gaseous mixtures

Selective catalytic oxidation of H2S over V2O5 supported on TiO2-pillared clay catalysts in the presence of water and ammonia

Selective oxidation of H2S to elemental sulfur over Ce–V mixed oxide and CeO2 catalysts prepared by the complexation technique

The performance of vanadia-doped zirconia-pillared clay (V/Zr-PILC) for the selective catalytic oxidation of H2S was investigated in this study. A series of vanadia-doped zirconia pillared clays (V/Zr-PILCs) with various amounts of vanadia were prepared and characterized using X-ray diffraction (XRD), surface area-pore volume measurements, chemical analysis, infrared (FTIR) spectroscopy, UV–vis-diffuse reflectance spectroscopy (UV–vis-DRS), X-ray photoelectron spectroscopy (XPS), and thermogravimetric (TG) analysis. V/Zr-PILCs showed better catalytic performance than Zr-PILC at temperatures ranging from 220–300 °C without any considerable SO2 emission. The H2S conversion over V/Zr-PILCs increased with increasing vanadia content up to 6 wt%. However, it decreased at higher vanadia loadings due to the decrease of surface area and to the formation of the crystalline V2O5 phase. The results of a regeneration experiment using 6 wt% V/Zr-PILC catalyst showed good reproducibility in its catalytic activity, even through five successive sulfidation-regeneration cycles at 280 °C.

Selective catalytic oxidation of H2S to elemental sulfur over V2O5/Zr-pillared montmorillonite clay

Dynamic analysis of removal and selective oxidation of H2S to elemental sulfur over Cu–V and Cu–V–Mo mixed oxides in a fixed bed reactor

The selective oxidation of hydrogen sulfide in the presence of excess water and ammonia was studied over V-Sb-O/TiO 2 catalyst. They showed very high conversion of H 2 S without any harmful emission of SO 2 . The investigation was focused to understand the roles of several oxides. Therefore, V 2 O 5 /SiO 2 , V 2 O 5 /TiO 2 , the mechanical mixture catalyst (V 2 O 5 +Sb 2 O 4 ) and V-Sb-O/TiO 2 are studied separately. TiO 2 support increased the activity and stability of V 2 O 5 . Sb 2 O 4 increased the reoxidation of reduced V 2 O 5 by supplying spillover oxygen through the boundaries of the metal oxides. VSbO 4 was one of the main active phase in V-Sb-O/TiO 2 mixed oxides.

Byung-Kook Park

Papers

Vanadium-antimony mixed oxide catalysts for the selective oxidation of H2S containing excess water and ammonia

Spillover effect for the oxidation of H2S in the presence of ammonia and water