Acid-Metal Balance of a Hydrocracking Catalyst: Ideal versus Nonideal Behavior

n-Alkane hydrocracking has been previously performed in a perfectly mixed flow reactor at temperatures from 473 to 553 K, pressures from 0.5 to 10 MPa, and molar hydrogen-to-hydrocarbon inlet ratios from 50 to 300 on a USY zeolite loaded with 0.5 wt % Pt1. For a given ratio of metal to acid sites, four important causes affecting the ideal character (i.e., the quasi equilibration of the (de)-hydrogenation reactions) were identified. In the investigated range of operating conditions, (1) a decreasing total pressure, (2) an increasing temperature, (3) an increasing molar hydrogen-to-hydrocarbon inlet ratio, and (4) a higher reactant carbon number lead to nonideality. A kinetic model for nonideal hydrocracking has been derived on the basis of a lumped reaction scheme. With literature values for the kinetic parameters, this allows us to rationalize the deviations from ideality in hydrocracking observed as a function of the operating conditions and to describe the high isomerization yield in ideal hydrocracking and the high cracking yield in nonideal hydrocracking. The results obtained with this lumped kinetic model will serve as a basis for the future development of single-event microkinetics (SEMK) for nonideal hydrocracking.