Fluidization regimes for alginate aerogel particles in a laboratory scale Wurster fluidized bed

Abstract

Fluidization regimes for alginate aerogel particles with two different particle sizes were characterized in a laboratory scale Wurster fluidized bed both in the annular zone and the tube zone. For both particle sizes, minimum fluidization and bubbling regimes were observed in both of the zones whereas pneumatic regimes existed only in the tube zone. Moreover, a new regime which was horizontal circular motion was identified for large particles in the tube zone. There existed two other regimes in the bed which were turbulent and circulatory particle motion regimes. All fluidization regimes were mapped on Kunii and Levenspiel diagrams. Circulatory particle motion regime was given on these diagrams for the first time. Furthermore, effects of particle size, batch volume, Wurster tube size, perforated plate geometry and partition gap height on the boundaries of each fluidization regime were investigated by measuring superficial air velocities at the onset and the end of each regime.