Fluidization Of Mixed Nanoparticles By Adding Coarse Particles

Abstract:Fluidization behavior of SiO2, ZnO and TiO2nanoparticles and their binary mixed powders are studied by adding FCC or Al2O3coarse particles with different diameters in the article. The result shows that pure and mixed nanoparticles are hardly to be fluidized in a fluidized bed, with pluging and channeling under low gas velocities and ABF under very high velocities. In the majority situation, mixed nanoparticles are fluidized layered, while the upper part shows ABF and the other part shows very large agglomerates.Al2O3coarse particles (D50=0.6mm and D50=1.0mm) show negative effect on fluidization of pure and mixed nanoparticles. Only Al2O3particles (D50=0.2mm) make a slightly influence (sometimes positive and sometimes negative) to fluidization of pure and mixed nanoparticles.All of the3kinds of FCC particles show positive effect on fluidization of pure and mixed nanoparticles. In general, fluidization does not improve obviously while the ratio of mess FCC particles over mess of nanoparticles equals0.15. Fluidization behavior will make a great progress if the adding ratio of FCC increases to0.3. And fluidization behavior will not change obviously if the adding ratio of FCC increases to0.45from0.3. The average sizes of agglomerates decrease with the adding ratio of FCC increasing.Layered fluidization is appeared in fluidized bed of mixed nanoparticles adding FCC particles. In the majority situation, the upper part shows ABF, but in beds of SiO2:ZnO=7:3or SiO2:ZnO=5:5, the upper part shows APF.FCC particles (61-90μm) make the best progress among the3kinds of FCC particles in general. However, FCCparticles (38-61μm) are more suitable of SiO2nanoparticles and mixed nanoparticle which SiO2particles are the majority. The reason is an FCCparticle (61-90μm)has a heavy enough mess and in the same time, the superficial area of FCCparticles (61-90μm) could be as large as they can. An advised adding ratio of FCC particles is0.3, considering both the effect to the nanoparticles and the economy.