Abstract
Particle mixing is a cost-effective assisted fluidization technique that significantly enhances the fluidization hydrodynamics by eliminating bed nonhomogeneities, suppressing hysteresis, and promoting nanoparticle deagglomeration. The addition of Geldart group A particles, which have superior fluidization behavior, can improve the poor fluidization of ultrafine hydrophilic nanoparticles. In this study, we investigated the collapse behavior of fluidized beds to characterize the hydrodynamic effect of particle mixing. To this end, we carefully monitored the bed dynamics by recording the local and global pressure transients in addition to video recording the bed fall. Adding Geldart group A particles even at only 2.3 vol% substantially slowed the bed dynamics and promoted nanoparticle deagglomeration. Compared with previously reported models, the size of nanoparticle agglomerates in this study showed significant reduction as a result of particle mixing.
[Display omitted]
•Particle mixing significantly improved the hydrodynamics of the fluidized bed.•Agglomerate size reduction as high as 66% was noted with <10% mixing.•Mixing 2.3% group A particles was more effective than four-fold increase in velocity.•Higher particle fractions failed to yield corresponding improvement in fluidization.