Modification of HDT catalysts of FCC feedstock by adding silica to the kneading paste of alumina support: Advantages and disadvantages

Abstract

The effect of Si incorporation at the stage of alumina preparation on physico-chemical properties and catalytic performance of NiMo/Al2O3 catalysts for FCC feedstock pretreatment has been studied. Silicon was added to alumina support by kneading. Si/Al molar ratio was 0–0.16. Supports and catalysts were characterized by XRD, MAS NMR spectroscopy, Raman and IR spectroscopies, nitrogen adsorption-desorption, HRTEM, UV-Vis DRS, XPS. Introduction of Si changes textural characteristics of supports and leads to the decrease in acidity of parent alumina caused by blocking of a part of surface OH groups by deposits of silicon compounds. Silicon addition promotes the formation of small amount of strong LAS and strong BAS. Incorporation of Si facilitates segregation of Ni from the NiMoS phase. Testing of catalysts in VGO hydrotreating shows that addition of silicon to alumina support by kneading improves hydrodesulfurization activity of catalysts. However, an improvement in HDN activity was not achieved.