Production of hydrogen from catalytic steam reforming of bio-oil using C12A7-O^--based catalysts

The production of hydrogen from the catalytic steam reforming of bio-oil, generated from fast pyrolysis of biomass, was investigated by using novel metal-doped catalysts of [Ca24Al28O64]4+·4O−/M (C12A7-O−/M, M = Mg, K, Ce). The features of the steam reforming of the bio-oil, including the effects of temperature, the metal-doped content and the S/C ratio (the ratio of mol steam to mol carbon fed) on the hydrogen yield, carbon conversion (mol carbon in production gases to mol carbon fed) and the distributions of the products were measured in the fixed-bed continuous flow reactor. It was found that the C12A7-O−/18% Mg catalyst gave the highest yield of hydrogen and the best carbon conversion among our tested catalysts. For the C12A7-O−/18% Mg catalyst, a hydrogen yield as high as 80% was obtained, and the maximum carbon conversion is up to 96% under the steam reforming condition (S/C > 4.0, GHSV = 10,000 h−1, T = 750 °C). The catalyst deactivation was mainly caused by the deposition of carbon (coke-formation). Initial catalyst activity can be partly maintained through periodic regeneration via the cleaning of the catalyst and the gasification of the carbon deposits. The catalyst characteristics and the intermediate species formed in the steam reforming processes were investigated by the XRD, XPS, ICP-AES and FT-IR measurements. The mechanism of the bio-oil steam reforming was addressed according to the above investigations.