Fluidization characteristics of Co/Al_20_3 nanoparticles in magnetic field

摘要

The fluidization behaviors of CO/Al_2O_3 aerogel nanoparticles were investigated in a 33 mm ID fluidized bed under the conditions of without magnetic field and with an axial magnetic field. The aerogel nanoparticles in agglomerate state can be fluidized and show a high bed expansion ratio at higher gas velocity, but channeling and slugging are marked features. With the assistance of an axial uniform magnetic field, the chains of magnetic particles disrupt large agglomerates into small agglomerates, which eliminate channeling and slugging. Thus the CO/Al_2O_3 aerogel nanoparticles could be fluidized smoothly when the magnetic field intensity exceeded 137 Oe, and the bed surfaces are even at higher gas velocity. The minimum fluidization velocities remarkably reduce with increasing magnetic field intensity. Moreover, Co/Al_2O_3 nanoparticles with magnetic field have longer collapse time than that without magnetic field.