Model for Calculation of Agglomerate Sizes of Nanoparticles in a Vibro-fluidized Bed

摘要

The behavior of SiO2 nanoparticles and the effects of operating conditions on nanoparticle agglomerate sizes have been investigated under conditions created in a vibro-fluidized bed (VFB). The experimental results reveal that the vibrations imposed in the bed can suppress slugging and/or channeling, in contrast to conventional fluidization with upflow only. The vibrations imposed in the particle bed affect both the minimum fluidization velocity and the agglomerate size, both of which decrease with increases in the energy introduced to the bed by the vibrations. The effect of vibrations on the agglomeration in vibro-fluidized beds of nanoparticles depends on the critical vibration frequency corresponding to a minimum agglomerate size. Both the amplitude and the frequency of the applied vibrations have significant effects on the agglomerate size. The experimental results and the consequent analysis reveal that increasing levels of vibrations in the bed yields finer agglomerates. The Richardson-Zaki scaling law combined with Stokes law permits the prediction of agglomerate sizes and the extent of initial bed voidage. The average agglomerate sizes predicted are in good agreement with those determined experimentally.