Experimental study of hydrogen production via the steam reforming of hydrogen-rich biomass pyrolysis gas under the catalysis of Ni/γ-Al₂O₃

In this paper, the steam reforming reactions of the hydrogen-rich biomass pyrolysis gas and methane (CH₄) were compared. The influence mechanism of hydrogen-rich biomass pyrolysis gas components on the reforming reaction of CH₄ and other low hydrocarbons was discussed, and the catalytic effect of Ni/γ-Al₂O₃ catalyst was revealed. H₂ could provide a reductive atmosphere to maintain the dynamic balance of the highly active Ni⁰ on the catalyst surface, so as to improve its catalytic activity. At the same time, biomass pyrolysis gas could inhibit the conversion of transition carbon to graphitic carbon, reducing the influence of carbon deposition on the catalytic activity of Ni/γ-Al₂O₃. In addition, the influence of operating conditions such as reaction temperature, the ratio of steam and carbon (S/C), as well as space velocity on the steam reforming reaction of hydrogen-rich pyrolysis gas was investigated. The increase of reaction temperature and S/C ratio effectively promoted the steam reforming of CH₄ and inhibited the production of carbon deposition. With the increase of space velocity, the competitiveness of CH₄ steam reforming reaction was weakened, whereas that of water gas shift reaction and CH₄ dry reforming was increased. Hence, the transformation of CH₄ was inhibited. This paper cound lay a foundation for the research on the mechanism of biomass pyrolysis gas steam reforming reaction and the development of high-efficiency catalysts.