Elutriation and agglomerate size distribution in a silica nanoparticle vibro-fluidized bed

Fluidization of nanoparticle agglomerates is a promising technique to process nanoparticles. However, possible elutriation of small agglomerates may cause significant loss of bed material. To obtain the elutriation behavior under stable operation, in this study the elutriation fraction of silica nanoparticle agglomerates is measured in a vibro-fluidized bed, which is operated for several hours. Among conditions with different fluidizing gas veloc-ities, Ug, and vibration strength, Lambda, the lowest elutriation fraction measured is around 5% after 7-hour fluid-ization. The elutriation fraction increases significantly with Ug, while varies slightly with Lambda. To help elucidating the elutriation behavior, the agglomerates at three different locations (bed surface, splash zone, and bed outlet) are sampled and their size distributions are determined. The elutriation rate constant is found to be much smaller than the literature results for ordinary particles, and the reasons are discussed in detail. Finally, an empirical correlation considering size distribution is proposed to fit the elutriation rate constant for the conditions in this study.

Automated summary

Fluidization of nanoparticle agglomerates is a promising technique for processing nanoparticles. This study measured the elutriation fraction of silica nanoparticle agglomerates in a vibro-fluidized bed under stable operation conditions. The results showed that the elutriation fraction increased significantly with fluidizing gas velocity but only varied slightly with vibration strength.