A molecular-level kinetic model was built for naphtha catalytic cracking process on pathway level. The computer-aided reaction network generation and kinetic model building were performed on an in-house software for petroleum molecular management.<br/>A series of reaction rules were summarized and implemented into reaction network generation software. The proposed reaction rules can be divided into several reaction families, including dehydrocyclization of paraffins to aromatics, dehydrogenation of naphthenes to aromatics, hydrocracking of paraffins to lower hydrocarbons, isomerization to isoparaffins, etc., which are commonly occurred on bifunctional catalyst (metal & acid sites). After applying the reaction rules to the molecules in the feedstock, a reaction network involving more than 300 species was established. The Langmuir-Hinshelwood-Hougen-Watson (LHHW) formula was used as basic reaction model. LHHW is suitable for heterogeneous catalytic reaction system considering the adsorption-surface reaction-desorption processes.<br/>Mathematical model for various types of reactor model were also built, such as axial-flow tubular reactor and continuous catalyst regeneration reformer. Due to the excess number of reactions involved in the model, a large number of parameters were needed to be fitted during the regression process. Hence, the tunable parameters reduction for the kinetic model was necessary. The linear free energy relationship (LFER) method was utilized to correlate the activation energy and the enthalpy of the reaction. Consequently, the number of fitting parameters reduced from thousands to dozens. Kinetic parameters were determined by minimizing the difference between model outputs and experimental results. The effect of the model shows good agreement with the experimental data for a range of process conditions.

Molecular-level kinetic model for naphtha catalytic reforming

256th National Meeting (2018)

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