Particle mixing in rotating fluidized beds: Inferences about the fluidized state

✍ Scribed by Gui-Hua Qian; Istv´n B´gyi; Robert Pfeffer; Henry Shaw; John G. Stevens

• Publisher: American Institute of Chemical Engineers
• Year: 1999
• Tongue: English
• Weight: 263 KB
• Volume: 45
• Category: Article
• ISSN: 0001-1541
• DOI: 10.1002/aic.690450705

✦ Synopsis

Particle motion in a rotating fluidized bed was studied by obser®ing the mixing of two layers of particles of different colors. The particles in the two layers were either nearly identical, except for their color, or were of different density and size distribution. All of the particles were in the Geldart-A classification for con®entional fluidized beds. After fluidization, but before mixing, the bed exhibited some fluid-like beha®ior, that is, the inner surface became radially uniform. For particle layers of the same material, mixing occurred after U was reached, with bubbles obser®ed at the mixing ®elocity. No experm fc imental difference between U and U could be discerned; they either coincided or m b m f c were nearly equal. Bubbles appeared to be responsible for particle motion and mixing.

When the denser particles are placed on the distributor, the mixing beha®ior was similar to that obser®ed for layers of the same material. Howe®er, when the less dense particles are placed on the distributor, mixing is dominated by differences in density and occurs before bubbles are ®isible.

p . 1998 attribute this difference to the fact that the experiments by Cody et al. were performed in a cylindrical vessel,