Characterization of fluidized bed layer inversion in a 191-mm-diameter column using both experimental and CPFD approaches

A bed containing equal volumes of 1.85mm glass beads (ρp=2500kg/m3) and 0.550mm ceramic spheres (ρp=3800kg/m3), was fluidized by water in a 191mm i.d. cylindrical column. The water velocity was varied from 16.5 to 52.5mm/s to investigate the phenomenon of layer inversion at three temperatures (5, 10 and 20°C). The inversion velocity was found to decrease by 7% on reducing the temperature from 20 to 10°C, with no further decrease at 5°C. The operating temperature had an important effect on the degree of separation between the two solids. In contrast to what has been reported for columns of smaller diameter, gross circulation was found to play an important role in enhancing particle mixing. Quantitative and qualitative predictions of layer inversion and binary component segregation at different liquid velocities and of chaotic circulation patterns were carried out by Eulerian–Lagrangian Computational Particle-Fluid Dynamics (CPFD) modelling, using Barracuda software. The predictions are in reasonable agreement with the experimental observations. ► Liquid fluidization layer inversion in a relatively large column. ► Temperature effect on the inversion velocity. ► Layer inversion predictions using an Eulerian–Lagrangian CPFD code and comparison with experiments.