| abstract |
A layered hydrocracking catalyst system has high middle distillate selectivity when used for hydrocracking a high sulfur and high nitrogen containing feedstock. The layered system comprises a first layer catalyst with contains a zeolite having a unit cell size of greater than about 24.35 Angstroms, and a second layer catalyst which contains a zeolite having a unit cell size of less than about 24.30 Angstroms. The layered system is particularly beneficial in terms of catalyst life and product selectivity for reactors operated under conditions of a high temperature profile. |