The Effect of Nickel Content on a NiMoS Catalyst for Deep Hydrodearomatisation of Polycyclic Aromatic Hydrocarbons

A series of NiMo catalysts with a low MoO₃/NiO mass ratio were prepared by introducing SiO₂ and Ni during the formation of the support. The supports were improved by adding SiO₂ to optimise the surface acidity properties, regulate the main structure of the NiMoS active phase, reduce the formation proportion of NiAl₂O₄, and improve the utilisation rate of Ni. The catalysts were improved by increasing the Ni content to adjust the Ni/Mo atomic ratio at the edge and corner positions of the NiMoS active phase to promote the generation and transfer of activated hydrogen. The NiMoS phase with high Ni content achieved good dispersion on the catalyst surface, reaching the highest hydrogenation saturation depth of aromatic hydrocarbon when the MoO₃/NiO mass ratio is 3 and the SiO₂ content is 5 wt.%. The catalysts with high Ni content also exhibit high activity and stability in removing Conradson Carbon Residue (CCR) during hydrotreating. Increasing the Ni content of the catalyst helps to remove impurities such as S and N from the residual oil.