Use of parallel inclined plates to control elutriation from a gas fluidized bed

The elutriation from a modified gas fluidized bed incorporating a set of parallel inclined plates was investigated. The presence of the plates resulted in a significant increase in the effective sedimentation area of the vessel, and hence retention of particles in the fluidized bed. Initially, a model describing the elutriation from a conventional fluidized bed was proposed, and the general framework validated using experimental data. The experimental data were also used to establish fixed values of two parameters in the model. The model of the conventional fluidized bed was then extended to describe the effect of the inclined channels in the modified fluidized bed. The extended model incorporated a kinematic approach to describe the particle trajectories within the channels, with a segregation efficiency, e , introduced to account for particle resuspension within the inclined channels. The segregation efficiencies were found to be consistent with those calculated from an empirical relationship obtained in a separate study for a solid–liquid fluidized bed system [Laskovski, D., Duncan, P., Stevenson, P., Zhou, J., Galvin, K.P., 2006. Segregation of hydraulically suspended particles in inclined channels. Chemical Engineering Science, submitted for publication]. The extended model of the modified fluidized bed provided a good description of the elutriation process, accounting for the effect of the number of inclined channels and the superficial gas velocity on the mass loss of particles from the bed. Further validation of the model was achieved by introducing much coarser particles in the feed.