Hydrodynamic characteristics of gas–solid tapered fluidized beds: Experimental studies and empirical models

• Hydrodynamic behaviors of tapered fluidized bed were investigated.
• Empirical correlations were derived to predict Umf, Umff, ΔPmax and H/H0.
• Effects of process parameters on fluidization of particles were studied.
• A proposed model was compared with other models.
• Predicted values were in good agreement with the experimental data.

Understanding the hydrodynamic behavior of tapered fluidized beds is essential for accurate design and better operation in these fluid–solid contactors. Minimum fluidization velocity, minimum velocity of full fluidization, maximum pressure drop and bed expansion ratio are more important hydrodynamic characteristics in tapered fluidized beds. In this study, based on experimental data, dimensional analysis has been used to develop dimensionless correlations for predicting hydrodynamic characteristics of Geldart B particles in tapered fluidized bed. The effects of bed geometry, static bed height, particle density, size, and sphericity and also interparticle forces on hydrodynamic behavior of tapered fluidized beds have been investigated. Numerical comparison indicated that the predictions of the present model are in good agreement with experimental data. The ability of the proposed models to predict hydrodynamic characteristics of fluidized particles has been compared to that of existing models in the literatures.

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