Obstructive Effect on Elutriation Due to Existence of Particles in Freeboard

抄録

In many previous investigations, the elutriation rate of multi component gas-solid fluidized beds has been reported to be in proportion to the concentration of particles in the bed. We, however, found the very interesting phenomenon that the ratio of elutriation rate to particle concentration gradually decreases as the concentration becomes larger. A simple model, in which the obstructive effect on elutriation due to suspended particles in the freeboard is taken into consideration, is proposed and applied to elutriation from a fluidized bed which consisting of two kinds of glass beads of different sizes. The virtual elutriation rate in the proposed model, which is the imaginary elutriation rate when no obstructive effect exists, agrees well with the common elutriation rate predicted by the equations proposed previously, such as that by Wen and Hashinger. The other parameter in the model, k_p, which relates directly to the magnitude of the obstructive effect, decreases as the superficial gas velocity becomes high.