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BACKGROUND : Light olefins are the basic feedstocks for the petrochemical industry. So far, the olefins yield from bio‐oil is noticeably lower than that from methanol, ethanol and naphtha, and thereby needs to be improved by optimizing catalysts and cracking conditions. The main purpose of this work is to selectively produce light olefins through the catalytic cracking of bio‐oil using the magnesium modified HZSM‐5 catalyst. RESULTS Catalytic conversion of bio‐oil and its model compounds into light olefins was performed using the Mg/HZSM‐5 catalyst. The highest olefins yield from bio‐oil was 0.25 kg olefins (kg−1 bio‐oil) with a carbon yield of 59.3 C‐mol% and nearly complete bio‐oil conversion. The reaction conditions and addition of magnesium into the HZSM‐5 zeolite can be used to control both olefins yield and selectivity. In addition, the yield of light olefins from the pyrolysis of bio‐oil is much lower than the level from bio‐oil catalytic cracking. CONCLUSION Moderately increasing the medium acid sites through addition of Mg into the zeolite effectively enhanced olefins selectivity and improved catalyst stability. The production of light olefins from bio‐oil is closely associated with the chemical composition and hydrogen to carbon effective ratios of feedstock. Copyright © 2012 Society of Chemical Industry

We investigated high catalytic activity of Ni/HZSM-5 catalysts synthesized by the impregnation method, which was successfully applied for low-temperature steam reforming of bio-oil. The influences of the catalyst composition, reforming temperature and the molar ratio of steam to carbon fed on the stream reforming process of bio-oil over the Ni/HZSM-5 catalysts were investigated in the reforming reactor. The promoting effects of current passing through the catalyst on the bio-oil reforming were also studied using the electrochemical catalytic reforming approach. By comparing Ni/HZSM-5 with commonly used Ni/Al2O3 catalysts, the Ni20/ZSM catalyst with Ni-loading content of about 20% on the HZSM-5 support showed the highest catalytic activity. Even at 450 °C, the hydrogen yield of about 90% with a near complete conversion of bio-oil was obtained using the Ni20/ZSM catalyst. It was found that the performance of the bio-oil reforming was remarkably enhanced by the HZSM-5 supporter and the current through the catalyst. The features of the Ni/HZSM-5 catalysts were also investigated via X-ray diffraction, inductively coupled plasma and atomic emission spectroscopy, hydrogen temperature-programmed reduction, and Brunauer-Emmett-Teller methods.