Catalytic Upgrading of Biomass-Gasification Mixtures Using Ni-Fe/MgAlO as a Bifunctional Catalyst.

Biomass gasification streams typically contain a mixture of CO, H, CH, and CO as the majority components and frequently require conditioning for downstream processes. Herein, we investigate the catalytic upgrading of surrogate biomass gasifiers through the generation of syngas. Seeking a bifunctional system capable of converting CO and CH to CO, a reverse water gas shift (RWGS) catalyst based on Fe/MgAlO was decorated with an increasing content of Ni metal and evaluated for producing syngas using different feedstock compositions. This approach proved efficient for gas upgrading, and the incorporation of adequate Ni content increased the CO content by promoting the RWGS and dry reforming of methane (DRM) reactions. The larger CO productivity attained at high temperatures was intimately associated with the generation of FeNi alloys. Among the catalysts' series, Ni-rich catalysts favored the CO productivity in the presence of CH, but important carbon deposition processes were noticed. On the contrary, 2Ni-Fe/MgAlO resulted in a competitive and cost-effective system delivering large amounts of CO with almost no coke deposits. Overall, the incorporation of a suitable realistic application for valorization of variable composition of biomass-gasification derived mixtures obtaining a syngas-rich stream thus opens new routes for biosyngas production and upgrading.