Abstract

Experimental data and theoretical considerations are used to analyze the effect of peripheral gas supply on the hydrodynamics and heat and mass transfer of spouting beds. A hydrodynamic model of the flow's structure in the dispersed phase is developed which yields a function that describes particle distribution in terms of residence time. The introduction of four peripheral flat gas streams produced a lowering of the maximum pressure drop across the bed and of the minimum fluidization velocity. In addition, this resulted in an increase of particle concentration in the centre of the bed (the spout) and its decrease in the peripheral zone, thus avoiding the generation of dead zones in the bed and the adherence of dispersed particles to the walls. This results in an overall increase in heat and mass exchange between the two zones and an improvement of the drying kinetics. © 2006 Elsevier B.V. All rights reserved.