Concerning the Impact of a Submerged Body on Particle Movement in a Fluidized Bed in Terms of Body-Bed Heat Transfer

Abstract: According to results of tracking a magnetolabeled particle in the monodisperse fluidized bed of silica-alumina catalyst, in which a gas-tight cylinder simulating a heat transfer surface was submerged vertically and in axial alignment with the apparatus, there has been confirmed the formation of a special zone near the body with the width up to 20 mm and local vertical circulation of particles. The zone is formed with a rise in gas velocity and a gradual deterioration of particle exchange with the core of the bed so that the time of the particle residence in the zone is increased up to 0.36-0.5 s, whereas in the core of the bed it is 0.25-0.4 s. The lower the initial height of the bed is, the lower the gas velocity at which a near-surface zone is formed. Formation of the near-surface zone can have a direct impact on the heat transfer rate and this fact should be taken into account when constructing models of external heat transfer in a fluidized bed.