Kinetic study of steam catalytic cracking of naphtha on a Fe/ZSM-5 catalyst

Abstract

A new six-lump kinetic model is proposed to describe the naphtha steam catalytic cracking on a Fe/ZSM-5 catalyst. The kinetic model contains 20 kinetic parameters and one for catalyst deactivation. The catalyst deactivation model was described by an exponential function depending on time-on-stream. Rate constants of the kinetic model were estimated by the least square regression analysis of the experimental data, obtained in a fixed bed reactor at temperatures of 620, 650 and 680°C. Pre-exponential factors and apparent activation energies were then calculated according to the Arrhenius equation. The simulated results illustrate that the six-lump kinetic model can well predict the product yields of naphtha steam catalytic cracking. Ethylene yield increases with the reaction temperature, while the yields of propylene and overall light olefins pass through maxima. The predicted results indicate that steam catalytic cracking of naphtha is better to be conducted at high temperature and short residence time of feedstock.