Industrial & Engineering Chemistry Research, Vol.54, No.44, 11040-11047, 2015
High-Temperature Gaseous H2S Removal by Zn-Mn-based Sorbent
Zn-Mn oxides supported on gamma-Al2O3 are experimentally evaluated as an adsorbent for removing H2S from gas streams in the temperature range of 350-4600 degrees C. Experimental results indicate that zinc and manganese oxide can be integrated to form a good solid solution for effective adsorption of H2S. With an operating temperature of 600 degrees C and 200 ppm of H2S on the gas stream, the adsorption capacity of H2S achieved with 10 wt % Zn-Mn/gamma-Al2O3 (ZMA) reaches 52 mg S/g at a gas hourly space velocity (GHSV) of 20 000 h(-1). Additionally, kinetic study is conducted to evaluate the activation energy. Results indicate that the activation energy. of ZMA IS 51 kJ/mol and that the reaction rate constant increases with increasing temperature. In addition, the H2S adsorption capacity of ZMA would be significantly increased as CO2, H-2, and CO are added into the gas stream individually. In the regeneration process, the activity of ZMA can be completely recovered with air at the low regeneration temperature of 300 degrees C. Furthermore, the, durability test results indicate that the sulfur:adsorption capacity achieved with ZMA is maintained at about 52 mg S/g at 600 degrees C for at least 6 cycles. Overall, the Zn-Mn-based adsorbent shows good performance and stability for H2S removal.