2-AREA MODEL FOR BUBBLE DISTRIBUTION IN A TURBULENT FLUIDIZED-BED OF FINE PARTICLES

The flow behavior of gas and solid was investigated in FCC simulator o f Phi 710(x) 4000/Phi 870 x 11000mm. The axial and radial distribution s were detected with matrix fiber-optic probes. It was found that the distribution of bubble diameter in the turbulent region of the fluidiz ed bed of fine particles was different from the results reported for l ab-scale experiments. Radially there were three areas, i.e., the centr al (r/R = 0 - 0.4), the intermittent or stable (r/R = 0.4 - 0.8) and t he near wall (r/R = 0.8 - 1.0) areas respectively. It was noticed that bubbles were almost non-existing at the near wall area. Hence, accord ing to the coalescence and splitting theory of bubbles, a two-area mod el of bubble diameter distribution was proposed and a dimensionless pa rameter (gamma(M)) regarded as an index for 'quality' of fluidization was deduced.