Segregation phenomenon in spouted beds

Abstract Preliminary experiments with spouted beds of binary mixtures of particles have shown that segregation according to size or density clearly occurs, with heavier particles going to the upper inside part of the annulus. Segregation tendency becomes less pronounced with increasing gas flow rate. During continuous operation, the concentration of coarse particles in the discharge stream was found to be initially lower than in the feed but it increased within a short time (10–50 min) to the feed concentration. However, the proportion of coarse particles in the bed solids ( x ) always remained higher than in the solids leaving the bed ( y ). A state of equilibrium was found to exist between these two concentrations, described by the following equation: y = x n The exponent n turned out to be a function of gas velocity and particle size of the individual components of the mixture, but, not of their proportions, nor of feed rate. An empirical correlation for n is proposed.