Abstract
Titania-alumina based catalysts were prepared and tested for hydrodesulfurization (HDS) and hydrocracking activity in the temperature range 300C to 350C in a fixed-bed reaction system using 4,6-dimethyldibenzothiophene (4,6-DMDBT) dissolved in n-hexadecane. Characterization results show that the metal-loaded titania-alumina possesses a high pore radius and pore volume but low surface area. The physical mixing with USY zeolite increased its surface area. The surface area was further increased upon mixing with nanoporous alumina. The total ammonia based acidity of the titania-alumina was lower than that of the ultra stable Y (USY) zeolite, but Ni-Mo loading was found to increase the acidity. The acidity of titania-alumina was further increased by mixing with nanoporous alumina and USY zeolite. All catalysts exhibited good HDS and hydrocracking activity for 4,6-DMDBT and n-hexadecane. The catalyst showing the highest HDS activity using 4,6-DMDBT was further tested and was found to have reasonable activity for both low- and high-sulfur vacuum gas oil feeds. This study demonstrated low-pressure HDS activity of the catalysts.