Mixed support of Y zeolite and titania-silica composite oxide for the heavy oil hydrotreating catalyst

Titania-silica composite oxides (CTS) were prepared by the sol-gel method combined with supercritical CO₂ drying, and then CTS was mixed with HY zeolite by different methods to obtain the composite supports (Y/CTS). The structure and acidity of the supports were further modified by P. Hydrotreating catalysts were prepared with Y/CTS as supports and Ni-W as active metal through the equal volume impregnation method. The effects of the mixed method and the content of HY zeolite in Y/CTS on the catalyst behavior were investigated. The results showed that the specific surface area and acidity of CTS can be adjusted by the addition of zeolite HY and the CTS structure retained with proper content of HY in Y/CTS; when the content of HY is more than 20%, the acidity amount of Y/CTS is higher than that of CTS, especially for the Bronsted acidity. P modification can adjust the acidity of the catalyst; the total acidity amount of the catalysts together with the fraction of Lewis acidity was increased. Shengli coker gas oil was used as feed stock to evaluate the hydrotreating performance of the catalysts. The results indicated that the hydrodesulferization (HDS) and hydrodenitrogenation (HDN) performance can be improved by using the mixed support Y/CTS with P modification.