The conversion of hydrocarbons contained in product gas from medium-temperature biomass gasification into syngas is a crucial step to improve the overall process energy efficiency of biofuel production. Catalytic steam reforming is an attractive option; however, deactivation by tar and carbon deposition is one of the main challenges of steam reforming catalysts. In this paper, we propose the implementation of robust, mineral-based, ice-templated materials for partial conversion of heavy tars. Ice-templation is an innovative process which produces mechanically resistant beads with radial porosity. We have studied the performance of ice-templated beads under relevant biomass gasification conditions. To investigate separately the impact of porosity and chemical composition, we compare dense alpha alumina beads with ice-templated alpha-alumina and ice-templated olivine beads. Impact was quantified in terms of gas composition, tar content and composition, as well as characterization of spent materials. The results show that thermal cracking (leading to severe carbon deposition) is the main process for dense beads, whereas ice-templated beads show tar conversion via reforming, especially when external steam is added, as well as WGS activity. Post-mortem analysis confirmed the stability of the pore structure, thus showing that ice-templated materials are an attractive option for the partial conversion of tars contained in product gas, particularly as guard bed for (expensive) tar reforming catalysts, thus improving the reliability of catalytic tar conversion routes.
Hakouk, K., Klotz, M., Di Geronimo, E., Ranieri, V., Pieterse, J. A. Z., Aranda Almansa, G., … Thorpe, S. (2018). Implementation of novel ice-templated materials for conversion of tars from gasification product gas. Fuel Processing Technology, 181, 340–351. https://doi.org/10.1016/j.fuproc.2018.10.009