CFD modelling of the hydrodynamics and kinetic reactions in a fluidised-bed MTO reactor

Abstract

This study presents a computational investigation of the hydrodynamics and kinetic reactions in a fluidised-bed MTO reactor. By integrating a kinetic model of methanol conversion with a two-fluid flow model, a gas–solid flow and reaction model was established. CFD analyses were performed, and the influences of various operating parameters were evaluated. The results indicate that the velocity, volume fraction and species concentration were considerably non-uniform in the axial and radial directions of the MTO reactor. Methanol conversion rate and product yields were more sensitive to the reaction temperature and pressure than to the initial methanol content in the feedstock. A gas velocity of 2.5–3.0m/s and a catalyst circulation rate of 100–120kg/(m2s) were found to be ideal for the current reactor. Coke deposition significantly affected the methanol conversion rate, product distribution and species selectivity. The ethylene-to-propylene ratio could be adjusted by varying the amount of coke on the catalyst.