Impact of Bed Loading on the Minimum Spouting Velocity of Polydisperse Simple-agglomerates in a Conical Fluidized Bed

The effect of static bed height on the minimum spouting velocity (ums) of polydispersed TiO2 agglomerates was studied experimentally and numerically in a conical fluidized bed. The experiments were carried out at different static bed heights with Gaussian and narrow-cut particle size distribution (PSD) through fluidization and defluidization stages. The bed consisted of simple-agglomerates with the sizes of 30-90 μm belonging to the Geldarts’ group A classification .The effect of PSD and interparticle force (IPF) on the predicted ums of the bed and hysteresis in the bed pressure drop were studied by an approach having coupled computational fluid dynamics and discrete element method (CFD-DEM). The experimental data showed that chosing a bed with Gaussian-type PSD led to more accurately predicting ums than when chosing one with the narrow-cut type PSD. The simulation results showed that the impact of IPF became more critical than that of the PSD type, because of an increase in static bed heights on the expected ums. The least discrepancy between the experimental data and simulation outputs was obtained in the bed with Gaussian-type PSD and low static bed heights, which confirmed the accuracy of simulation results. The results showed that the PSD-type and IPF led to a change in the type of the flow regime in the conical fluidized bed. The results showed that the bed with narrow-cut type PSD had a hydrodynamic behavior similar to that of spouting and slugging regimes, while the fluidization quality of the bed improved by the existence of fine particles.