Elutriation in a multisize particle fluidized bed was studied by fluidizing spherical glass beads of size range less than 595 and greater than 88 microns, in a 3-inch diameter column using air as the fluidizing medium. The variables studied were particle size distribution and superficial gas velocity. Particle distributions were made to follow a straight line on log-probability coordinates. The rate of elutriation could be described mathematically by an equation of the form: X/Xo = be-k + (1 - b)e-k in which X and Xo are the concentrations by weight of particles below a given size in the bed at times Θ and 0, respectively; b is a constant with value 0 ≤ b ≤ l; k1 < k2, both constants having dimensions of reciprocal time units. k1 increased with increasing superficial gas velocity and decreased with increasing particle size. The size distribution of the elutriated particles formed a log-normal distribution in which the geometric mean diameter increases with elutriation time, while the standard deviation decreases with time. © 1968, American Chemical Society. All rights reserved.
