1984 Volume 10 Issue 2 Pages 252-260
FCC particles and two other types of particles, which are “A particles” in Geldart's classification, were fluidized in beds of diameter 5.2 to 50 cm in a wide range of superficial gas velocities up to about 60 cm/s, in order to study the fluidized states of these particles. The latter particles are characterized by nearly the same mean particle size, size distribution and weight fraction of fines under 44 μm as FCC particles, but by larger particle densities.
Severe channeling occurred when deep beds of these heavy particles were fluidized, although FCC particles were found in a smoothly fluidized state. This channeling could be weakened when the fluidizing gas velocity was raised to a certain value, which was found to be dependent on the density of the particles. Good fluidity of particles in fluidized catalyst beds cannot always be given, due only to wide size distribution and small mean size of the particles, and the density of the particles has an important effect on the fluidity.
It was found possible to evaluate the fluidity of particles by plotting gas hold-up data based on the recirculation theory for bubble columns.
