MCM-22和ITQ-2分子筛负载型催化剂加氢裂化性能的对比研究

A series of supported WNi catalysts for hydrocracking of vacuum gas oil (VGO) were prepared using ITQ-2 and MCM-22 zeolites as supports. The catalysts were characterized by temperature-programmed desorption of ammonia, infrared spectroscopy of pyridine adsorption, and nitrogen adsorption. The acidities of WNi/MCM-22 and WNi/ITQ-2 catalysts were similar; but the surface area and pore volume of WNi/ITQ-2 were larger than those of WNi/MCM-22. The results of VGO hydrocracking indicated that WNi/ITQ-2 catalysts had higher catalytic activity and selectivity for middle distillates. The higher activity was due to the large secondary pore structure of the ITQ-2 zeolite and its rich accessible acidic centers. The reason for the higher selectivity was that products left acid centers rapidly and secondary cracking was avoided because of the large secondary structure.