An assessment of the ability of the TFM approach to predict gas mixing in a pseudo-2D bubbling fluidized bed

2D and 3D simulations of gas species diffusion in a pseudo-2D bubbling fluidized bed were carried out and compared to experimental measurements. Tracer gas concentration and solids velocity profiles measured throughout the bed showed great deviations of the 2D simulations due to negligence of the friction on the large front and back walls of the pseudo-2D unit and the inability to resolve gas species gradients across the thickness of the bed. 3D simulations circumvent these limitations and result in much more reasonable comparisons with experimental data. A clear lack of gas species diffusion was observed, however, and this was attributed to the negligence of particle-induced diffusion of gas species within the bed. Further work is recommended to investigate the modelling of particle-induced gas species diffusion in fluidized bed reactors.