Nine-lumped kinetic model for VGO catalytic cracking; using catalyst deactivation

Abstract

A new nine-lumped kinetic model is proposed to describe the VGO catalytic cracking using equilibrium fluid catalytic cracking catalyst (E-CAT) modified with ZSM-5 and MCM-41 additives. The kinetic model contained 18 kinetic parameters and 2 parameters for the catalyst deactivation. The catalyst deactivation model was described by an exponential function of time on stream and temperature. Kinetic parameters were estimated based on experimental data at 500, 530, 550, 580, 600, and 620 °C by fourth order Runge–Kutta algorithm and genetic algorithm method. Frequency factors and apparent activation energies were calculated according to Arrhenius equation. The apparent activation energies were mainly in the range of 20–75 kJ mol−1. The apparent activation energies for VGO to LCO + slurry oil, gasoline and alkanes were much lower than the other cracking paths. The optimum operation temperature which led to the maximum gasoline yield and maximum propylene yield were 550 °C and 600 °C respectively. The deactivation constant which was described by Arrhenius model, resulted in frequency factor of 23,695 and activation energy of 65.198 kJ/mol.