Hydrodynamic characteristics of a gas‐liquid‐solid fluidized bed containing a binary mixture of particles

Abstract

AbstractHydrodynamic characteristics were investigated in a cocurrent gas‐liquid‐solid fluidized bed containing a binary mixture of particles. The binary mixtures used were ten combinations of eight types of spherical particles differing in diameter and/or density. The density variation of the particles in the mixture was found to exhibit a stronger effect on the extent of solids mixing or segregation than did the size variation of the particles in the mixture. Additionally, a solids layer inversion phenomenon was found to occur in a bed of small, heavy alumina beads and large, lighter glass beads. The minimum fluidization velocity of binary mixtures correlated well empirically with the superficial gas velocity, weight fraction of jetsam particles, and particle terminal velocities of jetsam and flotsam particles. Bed expansion and gas holdup for a binary mixture were analyzed for three solids mixing states, namely, complete segregation, partial intermixing, and complete intermixing. The analysis indicates that the serial model, or segregation model, predicts the bed voidage satisfactorily even when the bed is at the complete intermixing state.