Iron-based catalyst (Fe2-xNixTiO5) for tar decomposition in biomass gasification

In this study, a novel Fe2-xNixTiO5 catalyst for potential applications in biomass gasification gas cleaning/upgrading was investigated. The material was successfully synthesized through combined mechanical activation and microwave firing. Catalytic steam reforming was studied in a fixed bed tubular reactor, using a mixture of toluene and naphthalene as model tar compounds as well as downstream a fluidized bed gasifier. Fe2-xNixTiO5 catalyst showed high activity in converting the model compounds at temperatures higher than 700 °C. The catalyst exhibited a tar conversion of 78% at 800 °C when exposed to biomass-derived gas from a bubbling fluidized bed gasifier. Nevertheless, the catalytic activity declined with increased time on stream due to structural changes in iron active phases, caused by redox conditions of the producer gas. Furthermore, thermodynamic calculations suggest that sulfur chemisorption on the nickel surface, may also contribute to the catalyst deactivation.