Catalytic Steam Reforming of Aqueous Phase of Bio-Oil over Ni-Based Alumina-Supported Catalysts

Abstract

Production of hydrogen (H2) from catalytic steam reforming of the aqueous phase of bio-oil was investigated in a fixed bed tubular flow reactor over nickel-based alumina-supported catalysts promoted with magnesia (Ni-MgO/Al2O3). The effects of time, amount of Ni, preparation condition, and initial bio-oil to water ratio on the yield of various outlet gases including hydrogen was investigated at 850 °C, and the outlet gas distributions were obtained. The average H2 yield was very low with a maximum of 30% over the alumina support when the aqueous phase of the bio-oil at a bio-oil to water ratio of 1 was employed. The hydrogen yield nearly doubled with the addition of 12.8% nickel and 33.3% magnesia for the three bio-oil aqueous phase samples at various bio-oil to water ratios. This effect was more pronounced in the aqueous bio-oil phases with greater water content. On the contrary, the effect of the preparation method on H2 yield was more pronounced in the aqueous phase samples with lower water content. Among the catalysts tested, the highest H2 yield (61%) was achieved over Ni-MgO/Al2O3-3 with the aqueous phase of bio-oil with a bio-oil to water ratio of 1/1, indicating that a greater bio-oil to water ratio does not necessarily provide greater H2 yield.