Gas Classification of Particles Using a Packed Bed

Abstract

Gas classification of particles using a packed bed is, for the first time, proposed and tested for two materials, i.e., glass ballotini and microcrystalline cellulose (MCC). A 2 m long column with 9.5 mm diameter is packed with 2 mm spherical particles. The particles to be classified are injected into the inlet of the packed bed by a carrier gas. Measurements of the breakthrough curves of the particles are carried out at the outlet of the packed bed. The results show that the particle elution order is particle size dependent with large particles elutriated faster than small ones. Taking the particle size into account, the retention time of irregular MCC particles is much longer than that of spherical glass beads and the difference is attributed to the particle shape and cohesiveness. Based on the findings, binary mixtures of both, glass and MCC beads are injected into the packed bed for the classification experiments. The results show different dependence on the superficial gas velocity of the particle classification efficiency. The particle classification efficiency of glass particles increases with decreasing superficial gas velocity, whereas that of MCC particles increases with increasing superficial gas velocity.