Gas mixing in fluidized beds containing screen packings

Abstract

AbstractGas mixing was studied in a fluidized bed containing hollow, open‐wall packings using a continuous injection of oxygen as a tracer.During bed expansion, the reciprocal of mixing length, u/E1, for a gas‐fiuidized bed containing packings of dimension less than 3‐in. was found to decrease and then increase with the expansion ratio, Δ, passing through a minimum, in contrast to an unpacked fluidized bed for which no minimum u/E1, was reported.The minimum u/E1, occurred always at Δ = 0.30, independent of column diameter, of the shape or of the size of the packing, and of the size of the fluidizing particle. Values of the minimum u/E1's for a fluidized bed packed with various screen cylinders depended upon the size of the packing, dn, and of the fluidized particle, d1,. An empirical correlation of (u/E1)mn, with d1, and dn is presented.