Insights into the High Activity of Hydrotreating Catalysts for Heavy Gas Oil

Abstract

The objective of this work was to develop a highly active hydrotreating catalyst for processing heavy gas oil to provide qualified feedstock for hydroisomerization or a hydrocracking unit. The NiMo/γ-Al2O3 catalysts doped with phosphate were prepared by introducing two kinds of additives, and the influencing factors for highly active hydrodenitrogenation (HDN) were revealed. TEM analysis results showed that the catalyst with a small MoS2 stack length tended to have high activity due to more active sites being exposed. Laser Raman spectroscopy demonstrated that the catalysts contained PMo12O403− metal active phases. For industrial heavy VGO feedstock, the nitrogen content can be reduced to 2 ppm with a hydrotreating process. The VI of the hydrotreated product can be improved from 132 to 145 after hydrotreatment, which is necessary to produce group III base oil as the most valuable base oil type. This work provides an insight into the high activity of hydrotreating catalysts for industrial lubricant hydroprocessing.