Improved carbon disulfide conversion: Modification of an alumina Claus catalyst by deposition of transition metal oxides

Abstract

Destruction of CS2 in the modified Claus process plays a vital role in achieving high sulfur recovery (>99.9%). Although it has lower catalytic activity for CS2 hydrolysis than titania, alumina has been widely used in Claus plants for conversion of sulfur species into elemental sulfur, because it is less expensive, highly active for the Claus reaction and mechanically robust. This research explores improving CS2 hydrolysis on Claus alumina catalyst by modification with 1 wt.% of either CuO, TiO2, Fe2O3, Co2O3, Sc2O3 or Na2O. These modified catalysts were tested using the first catalytic convertor conditions. While catalyst impregnation with most of the metals described above leads to minor improved CS2 conversion, the deposition of both Cu2+ and Ti4+ stood out for resulting 22.6 and 33.7% higher activity, respectively. Results suggest that the improved catalytic activity can be explained by reduced hydrophilicity (increased hydroxyl dispersion) and somewhat increased basicity on the surface of the catalysts.