HYDROCRACKING CATALYSTS BASED ON THE NEW LARGE-PORE ITQ-21 ZEOLITE FOR MAXIMIZING DIESEL PRODUCTS

摘要

Hydrocracking catalysts based on the new large-pore ITQ-21 zeolite show a higher selectivity to diesel-range products at high conversions as compared with USY and Beta based catalysts. The results are explained considering the particular topology of ITQ-21, which favors the diffusion of the intermediate diesel products decreasing their recracking into lighter compounds. A benefit in both activity and selectivity to middle distillates in ITQ-21 based catalysts has been observed when the metal function (NiMo) is first impregnated on γ-Al_2O_3 and then physically mixed with the zeolite as compared to a catalyst prepared by impregnating the metal precursors on a physical mixture of γ-Al_2O_3 and ITQ-21.