Study of Bifunctional Hydrocracking and Hydroisodeparaffinization Catalysts Based on Zeolites and Alumophosphates, Part 2: Effect of the Activity of Hydrogenating and Acidic Components on the Activity and Selectivity of Hydroisodeparaffinization Catalysts

Abstract

Two different series of bifunctional hydroisodeparaffinization catalysts with deposited palladium and based on SAPO-11 and SAPO-31 are fabricated and studied, with (1) varied activity of the acidic component at a constant activity of the hydro–dehydrogenating component and (2) varied activity of the hydro–dehydrogenating component at a constant activity of the acidic component. It is shown that the temperature of 90% n-decane conversion on the catalysts with the same hydro–dehydrogenating activity depends linearly on the overall activity of the acidic catalyst component. The character of this dependence is identical for both structural types of SAPO-11 and SAPO-31 silicoalumophosphates. The bifunctional catalysts based on SAPO-31 are much more active than those based on SAPO-11. At the same overall activity of the acidic component, the temperature of 90% n-decane conversion on the Pd/SAPO-31 catalysts is 50°C lower than on the Pd/SAPO-11 catalysts. Ways of controlling the overall activity and selectivity of a hydroisodeparaffinization catalyst by varying the activity of the acidic and/or hydro–dehydrogenating component of a bifunctional catalyst are shown. An increase in the hydro–dehydrogenating activity of the catalyst enhances the hydroisomerizing activity of a bifunctional catalyst with virtually no changes in selectivity toward isomers. An increase in the overall activity of the acidic component also enhances the hydroisomerizing activity of a bifunctional catalyst, but appreciably alters its selectivity toward isomers.