Abstract：Three kinds of carbon modification Ni-Mo-Al₂O₃ hydrodesulfurization catalysts were prepared through incorporating carbon into the catalysts at different stages of catalyst preparation. The catalysts were characterized by BET, XRD, H₂-TPR and HRTEM, and their catalytic performance was tested. The results show that the incorporation of carbon into Ni-Mo-Al₂O₃ is benefit for improving the hydrodesulfurization performance of the catalysts. More octahedral Mo can be formed by pre-carbon coating method in which the carbon is incorporated onto the alumina support before the active component loading or by co-impregation method in which the carbon is added into the catalyst alone with the active components loading. The catalysts prepared by co-impregation method exhibit higher dispersion of active components and more number of stacking layers of MoS₂ nano-particles. Compared with the catalyst without carbon modification, the desulfurization degree of the catalysts is increased by 6.8%. The catalysts prepared by pre-carbon coating method exhibit higher dispersion of active components. Compared with the catalyst without carbon modification, the desulfurization degree of the catalysts is increased by 5.1%. The carbon modification Ni-Mo-Al₂O₃ is also prepared by post-carbon coating method of incorporating carbon into the catalyst after the active component loading, and its hydrodesulfurization catalytic performance is relatively low compared with the catalyst without carbon modification.

Keywords: carbon modification; hydrodesulfurization; hydrotreating catalyst