Effect of sulphur during the catalytic partial oxidation of ethane over Rh and Pt honeycomb catalysts

The impact of sulphur addition (2-58 ppm) during the catalytic partial oxidation (CPO) of ethane was investigated on Rh- and Pt-based honeycomb catalysts tested under self-sustained high temperature conditions. Both steady state and transient operation of the CPO reactor were investigated particularly with regards to poisoning/regeneration cycles. A detailed analysis of products distribution in the effluent and a heat balance of the CPO reactor demonstrates that sulphur reversibly adsorbed on Rh selectively inhibits the ethane hydrogenolysis and, to a lower extent, steam reforming reaction. A further, simultaneous adverse effect of S on the kinetics of the reverse water gas shift reaction on Rh catalyst operating at temperatures < 750 degrees C can cause an unexpected increase in the H-2 yield above its equilibrium value for low concentrations of the poison. Pt catalyst is less active for those reactions but in turn is more S-tolerant. Copyright (C) 2012, Hydrogen Energy Publications, LLC. Published by Elsevier Ltd. All rights reserved.