CPFD simulation of cluster effect on mass transfer and reaction in downer with FCC particles

In this work, a cluster-based mass transfer and reaction model was proposed according to large number of simulation results by conducting ozone decomposition inside spherical cluster, which is more realistic compared with the conventional homogeneous description of mass transfer and chemical reaction process. Then, this model was coupled with three-dimensional Computational Particle Fluid Dynamics (CPFD) approach to simulate the ozone decomposition in pilot-scale gas-solids downer. According to the comparison between simulation results and experiment measurements, it was found that the model sufficiently considering the clustering effects on the hydrodynamics and chemical reaction predicted better ozone concentration distribution than the model based on homogeneous assumption. Meanwhile, the comprehensive model with consideration of cluster could accurately predict the gas-solids flow behaviors and reaction characteristics with different particle properties under different operating conditions. Finally, the effects of operating conditions such as superficial gas velocity and solids circulating flux on the hydrodynamics and reaction characteristics inside downer were fully analyzed on the basis of the accurate model predictions.