The Role of Acidity for Vacuum Gasoil Hydrocracking over Silica-Alumina Based Nickel-Molybdenum Catalysts (SS26.6)
A series of Ni-Mo hydrocracking catalysts based on amorphous silica-alumina (ASA) with Si/Al=0.3-1.5 was prepared using chemicals and methods available for catalyst plants. FTIR data of adsorbed CO was shown that the concentration and strength of Brønsted (BAS) and Lewis acid sites (LAS) on the support and catalyst surfaces depend on the Si/Al ratio in the initial ASA. The catalysts were tested in vacuum gas oil (VGO) one-through hydrocracking in a laboratory-scale high-pressure flow reactor under typical industrial hydrocracking conditions. The effect of catalysts acidity on the activity, selectivity and products yield was discussed. The highest diesel fraction yield (>60 wt % at 400°C) was achieved in the presence of the Ni-Mo/ASA(Si/Al = 0.9)-Al2O3 catalyst with the strongest BAS.