Partic. vol. 29 pp. 1-15 (December 2016)
doi: 10.1016/j.partic.2016.01.004

Flow-regime transitions in fluidized beds of non-spherical particles

H. Kruggel-Emden^*, K. Vollmari

kruggel-emden@leat.rub.de

Abstract

Fluidized beds frequently involve non-spherical particles, especially if biomass is present. For spherical particles, numerous experimental investigations have been reported in the literature. In contrast, complex-shaped particles have received much less attention. There is a lack of understanding of how particle shape influences flow-regime transitions. In this study, differently shaped Geldart group D particles are experimentally examined. Bed height, pressure drop, and their respective fluctuations are analyzed. With increasing deviation of particle shape from spheres, differences in flow-regime transitions occur with a tendency for the bed to form channels instead of undergoing smooth fluidization. The correlations available in the literature for spherical particles are limited in their applicability when used to predict regime changes for complex-shaped particles. Hence, based on existing correlations, improvements are derived.

Graphical abstract

Keywords

Fluidized bed; Flow regimes; Non-spherical particles; Pressure drop and fluctuations; Bed height