Single-Event Microkinetic Model for Long-Chain Paraffin Hydrocracking and Hydroisomerization on an Amorphous Pt/SiO 2 ·Al 2 O 3 Catalyst

Abstract : Hydrocracking of a long-chain paraffin, n-hexadecane, was carried out on an amorphous Pt/SiO2·Al2O3 bifunctional catalyst. Through an isomerization selectivity analysis, it was found that the behavior of the system approaches the ideal hydrocracking conditions. The kinetic modeling of paraffin hydrocracking and hydroisomerization was realized by using the principles of the single-event microkinetic concept. The single-event microkinetic concept has been demonstrated to be efficient in the modeling of acid-catalyzed reactions. A lumped single-event microkinetic model was developed for heavy paraffin hydrocracking in the liquid phase, which considers a group of only nine rate constants for the reactions on the acid phase of the catalyst. The model’s lumping coefficients were calculated by the lateral-chain method, a computer-based approach that does not imply the generation of the whole reaction network. The rate constants were estimated at 340 °C from n-hexadecane hydroisomerization experiments in a plug-flow pilot reactor. The kinetic model was validated (upon extrapolation) by the simulation of two heavier paraffin feeds: a C20−C30 wax mixture and pure squalane. The agreement between the calculated and experimental data was satisfactory.