Effect of fluidized bed diameter on fluidization dynamics

Conference paper (2014)

Authors

Vikrant Verma Eindhoven University of Technology
J.T. Padding Eindhoven University of Technology
Niels G. Deen Eindhoven University of Technology
J. A.M. Kuipers Eindhoven University of Technology
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Published Date

2014

Language

English

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Abstract

The effect of the bed diameter on the gas-solids flow characteristics inside a cylindrical fluidized bed is investigated numerically using a two-fluid model based on the kinetic theory of granular flow. Particle bed diameters of 0.10, 0.15, 0.30 and 0.60 m are studied, containing particles of 1.1 mm diameter and a density of 800 kg/m3 (Geldart B), using an inlet gas velocity of 2.5Umf. The equivalent bubble diameter shows an increasing trend with height in the bed and bed diameter. Slugging behavior is observed in a smaller bed and/or above a bed height of approximately twice the bed diameter. The porosity near the axis is higher for a smaller bed and gradually decreases for a larger bed. Different particle circulation patterns are observed for different bed sizes. The center of circulation vortex at the bottom for a smaller bed lies approximately at r/R = 0.5 and this center is shifted to r/R = 0.8 for a larger bed. The upper particle circulation obtains a more elongated shape for a smaller and deeper bed in comparison to a larger bed diameter. The particle flow characteristics are nearly the same for the 0.30 and 0.60 m diameter beds, irrespective of the difference in bubble size. This shows that the bed size effect levels off beyond a 0.30 m diameter column for Geldart B particles.