Procedure to prepare a supported trimetallic catalyst for production of ultra low sulfur diesel and its application

Abstract

According to this invention, a Ni—Mo—W trimetallic catalyst supported on porous alumina is obtained that shows very high activity for hydrotreating (HDT) of gasoils, particularly deep hydrodesulfurization (HDS) and hydrodesnitrogenation (HDN) of straight run gasoil in conditions of moderate pressure. When the catalyst is applied to HDT of diesel, the NiMoW catalyst exhibits high catalytic activity. The content of sulfur and nitrogen in the resulting diesel can be reduced from 13,200 to 10 ppm and nitrogen from 360 ppm to less than 1 ppm, under moderate pressure, temperature and space-velocity (LHSV) similar to those of an industrial unit. The catalytic composition, of trimetallic type, is prepared from an alumina support of high surface area to which a solution containing a metal precursor of an element of group VIB is added, followed by other solution that contains one of the precursors of the active metallic phase, a solution containing another of the precursors of the active metallic phase from group VIB, a metal promoter of group VIII and an additive promoter of acidity from group VB, and finally another solution containing a metal of group VIB, a metal of Group VIII and an organic compound, the used route promotes the preferential formation of well dispersed structures of the used metals on the support of porous alumina, less refractory to sulfidation, with high stacking and short lengths of metal sulfides formed in the resulting hydrodesulfurization catalyst. In the formulation, at least a percentage, but not all the Mo is replaced by W, in a Mo/W molar ratio of 0.6 to 2.0.