Modeling Ideal and Nonideal Hydrocracking of Paraffins Using the Single-Event Lumped Parameter Hybrid (SELPH) Model

The SELPH (single-event lumped parameter hybrid) model previously developed was used to simulate hydroconversion of n-octane and n-undecane over a wide range of operating conditions, in order to cover both ideal and nonideal hydrocracking behavior. The fundamental kinetic parameters used in the simulations were estimated previously from n-octane hydroconversion experimental data. Results of simulations demonstrate that predictions of the model for the effect of (i) operating pressure, (ii) reaction temperature, (iii) chain length of feed hydrocarbon, and (iv) hydrogen-to-hydrocarbon inlet molar ratio on the ideal (and nonideal) character of hydrocracking are in complete agreement with the general trends reported in the literature. The model allowed identification of intervals of the operating variables in which product selectivities are a unique function of total conversion, i.e., an ideal hydrocracking region, while, in the region of nonideal hydrocracking, the model accurately describes the changes of product selectivities as a function of operating conditions.