CFD modeling of the hydrodynamics and reaction kinetics of FCC fluidized-bed reactors

The hydrodynamics and reaction kinetics of gas-solid fluidized beds containing fluid catalytic cracking. (FCC) particles were simulated using computational fluid dynamics (CFD). Drag models of Gidaspow and Syamlal and O'Brien overestimated the drag force for the FCC particles and predicted a greater bed expansion in comparison to the experimental data. The modified Syamlal-O'Brien drag model based on the minimum fluidization conditions of the FCC particles predicted the expected bubbling fluidization behavior and simulated a bed expansion in agreement with the experimental data. The overall trend of the time-averaged voidage through the bubbling bed was simulated reasonably well at different superficial gas velocities. An additional transport equation with a kinetic term for ozone decomposition was included in the Eulerian-granular multiphase model. The computed conversions of ozone with various catalyst inventories were higher than those measured experimentally. The deviation could in part be the result of the effect of a gas distributor, which was not considered in the CFD simulation.