The effect of metal type on the sulfur tolerance of catalysts supported on niobia for sour water-gas shift reaction

Hydrogen production via water-gas shift (WGS) reaction using heavy oil residues as syngas source is an attractive way to improve refinery margin. However, this low cost syngas may present significant concentration of sulfur, leading to poisoning of usual WGS catalysts. Searching for sulfur tolerant catalysts, the performance of niobia supported platinum, gold and copper catalysts was evaluated under near-industrial conditions, in the absence and presence of H2S. Cu/Nb2O5 catalyst was inactive, even under clean conditions. Au/Nb2O5 presented higher activity and complete deactivation when exposed to sulfur, but recovered its catalytic activity with the removal of H2S from the reaction mixture, indicating a reversible deactivation. Pt/Nb2O5 catalyst was the most suitable among the catalysts evaluated to be used in sour conditions, not deactivating when exposed to 50 ppm and 1000 ppm of H2S. (C) 2017 Hydrogen Energy Publications LLC. Published by Elsevier Ltd. All rights reserved.