LATERAL DIFFUSION OF SOLIDS IN A FLUIDIZED-BED WITH SUBMERGED VERTICAL TUBES

The diffusion coefficient of solid particles in a fluidized bed with submerged vertical tubes as a function of fluidization conditions and of tube spacing was investigated by means of an unsteady tracer method for three bed particles: coal, char and sand. It was shown that in case of a bed with submerged tubes the dependence of the diffusion coefficient on fluidization velocity is very weak, contrary to that in a free bed. Empirical equations for the lateral diffusion coefficient in beds with submerged tubes were obtained. A modification of a theoretical model allowing the diffusion coefficient to be described as a function of the tube spacing is proposed and positively tested.