Nanoparticles, And Mixtures Thereof Fluidization In The Fluidized Bed Of Magnetic Field

The fluidization behavior of SiO₂, ZnO, TiO₂ and Al₂O₃nanoparticles in glass pip with diameter of 4 mm is investigated. Thereexisted fixed bed, plug formation, and channeling at the low superficialgas velocity. There exist two areas even at high gas velocities for SiO₂,TiO₂ and Al₂O₃ nanoparticles in traditional fluidized bed, smallagglomerate bubbling fluidized (ABF) area at the upper and bigagglomerate de-fluidized area at the bottom. By adding cast iron particleswith the average size of 2mm into the fluidized bed as magnets, bigagglomerates and channeling formed by SiO₂ nanoparticles at lowsuperficial gas velocity were broken up then, the bubbling and elutriationwere also restrained because cast iron particles vibrated violently abovethe distributor under oscillating magnetic filed engendered by a magneticstator and AC current.The agglomerate particle fluidized (APF) of SiO₂ nanoparticlesshowed liquid-like properties and the agglomerates circulated in thefluidized bed just like fluid. When the fluidization ability of ZnO, TiO₂and Al₂O₃ nanoparticles was poor in a traditional fluidized bed or even inthe magnetic fluidized bed with adding coarse magnets, the fluidizedSiO₂ nanoparticles were used as the fluidized medium in order to improvetheir fluidization ability. It was found that homogeneous mixtures formedwhen ZnO nano-particles were added in the fluidized bed of SiO₂nanoparticles, and the maximum mass fraction of nano-ZnO that canform homogenous mixtures is more than 90%. The stable operation areaof the APF was determined by the mass fraction of additivenano-particles and magnetic field intensity, and the stable operation areadecreased with increasing the mass fraction of additive nano-particles.Finally, the Matsuda's model and the Richardson-Zaki equation wereused to check the relation between the agglomerate size and the minimumfluidization superficial gas velocity of SiO₂ nanoparticles and theexpansion degree of nanoparticle mixtures, respectively. Model forestimating the terminal velocity of the mixture formed by APF and ABFnano-particles is proposed for further research in mixed nano-particles and its application in the future.