Ternary oxide-supported bimetallic nickel-copper catalysts for a single step high temperature water gas shift of biogas reformate

Abstract

Promoted ternary oxide based bimetallic catalysts with nominal composition of 3%Ni5%Cu/CeZrM (where M = La, Mg, Y, Gd or Ca) were prepared by surfactant-assisted route and tested for the high temperature water gas shift reaction. The catalysts were initially screened at 500 °C at atmospheric pressure in a packed bed tubular reactor using 30%CO/70%N2 gas. The Ca promoted catalyst showed the best performance, and was subsequently tested using simulated reformate gas of composition: 46.2%CO, 8.5%CH4, 7.2%CO2 and 38.1%H2 (obtained from biogas dry reforming). Effects of catalyst preparation method: (i.e. impregnation method (atmospheric pressure or vacuum), surfactant/metal ratio (S/M = 0–1.25) and calcination temperature (425–650 °C) were tested. Operating conditions: (i.e. reaction temperature (450–550 °C), steam/CO molar ratio and reactor pressure (atmospheric–250 psi) were also studied. Structure-activity relationships developed to correlate catalyst characteristics to performance showed that catalyst activity was highly dependent on Cu reducibility, support basicity and metal dispersion.