Currently, scientific research and practical results in the hydrotreating catalyst in and abroad mainly be: improving catalyst hydrogenation activity and life by using new type of composite carrier, and modulation of the active ingredient, introducing appropriate additives and metal complexing agent. In the oil refining field, Y-Al₂O₃ is the preferred carrier for the hydrotreating catalyst, which is also most widely used of catalyst carrier currently.

 

However, since a single alumina carrier is easy combine with the active ingredient (tungsten trioxide, nickel oxide) and produce a strong interaction, thereby generating a new phase without any catalytic activity; in addition, when in the treatment of high nitrogen gasoline and diesel hydrotreating, with the only one L acid of Y-Al₂O₃, it comes out a strong adsorption with the basic nitrogen, thereby inhibiting the performance of deep hydrodesulfurization. Therefore, the application of this catalyst with single alumina carrier is limited in heavy fraction oil.

 

This paper introduces one kind of light oil hydrodesulfurization denitrification catalyst which has excellent properties, such as high specific surface area, denitrification and hydrodesulfurization activity; the multi oxide Al₂O₃-ZrO₂-SiO₂-TiO₂ as the composite carrier, quaternary metal W-Mo-Ni-Co as the active components, P as additive. In this composite carrier system, the proportion of moderate and strong acid of carrier surface acidity has been improved, which is conducive to the open-loop and fracture of the heterocyclic, thus to improve denitrification activity.

 

Take the quaternary metal W-Mo-Ni-Co as the active components, additives P added, and configured to immersion liquid with stable solubility; besides, fractional saturation impregnation technique is used to load active metal components and additives, in that way, the metal dispersion and utilization has been improved. Wherein, tungsten trioxide occupies the largest proportion of the catalyst, for about 12 to 35%, which also indirectly shows its importance. A small amount of complexing agent is added during the impregnation for improving the stability of total immersion.