Hydrogen bromide in syngas: Effects on tar reforming, water gas-shift activities and sintering of Ni-based catalysts

Abstract

Hydrogen bromide is an emerging impurity of syngas formed during gasification of electronic and municipal solid waste. The influence of HBr on catalytic activity and deactivation of various Ni-based tar reforming catalysts was investigated. The data demonstrate the detrimental effect on catalytic properties (1) occurs at HBr concentrations above 500 ppmv, (2) is more severe compared to HCl and (3) varies greatly with the catalyst structure. The characterization of spent catalysts revealed that the formation of chemisorbed Ni-Br species, enhanced Ni sintering and depletion of NiO-Al2O3 sites could be the reasons for the loss of tar reforming and water-gas shift activities. On the other hand, no significant effect of HBr on catalyst coking was observed. The comparison of different catalysts demonstrated that the negative HBr impact can be successfully mitigated by developing a nanostructured catalyst with high porosity and Ni dispersion that ensure the strong Ni-support interaction.