Modeling Axial Mixing of Fuel Particles in the Dense Region of a Fluidized Bed
Journal article, 2020

A semiempirical model for the axial mixing of fuel particles in the dense region of a fluidized bed is presented and validated against experimental magnetic particle tracking in a fluid-dynamically downscaled fluidized bed (Köhler et al. Powder Technol., 2017, 316, 492-499) that resembles hot, large-scale conditions. The model divides the bottom region into three mixing zones: a rising bubble wake solid zone, a zone with sinking emulsion solids, and the splash zone above the dense bed. In the emulsion zone, which is crucial for the mixing, the axial motion of the fuel particle is shown to be satisfactorily described by a force balance that applies experimental values from the literature and an apparent emulsion viscosity of Newtonian character. In contrast, the values derived from the literature for key model parameters related to the bubble wake zone (such as the upward velocity of the tracer), which are derived from measurements carried out under cold laboratory-scale conditions, are known to underestimate systematically the measurements relevant to hot large-scale conditions. When applying values measured in a fluid-dynamically downscaled fluidized bed (Köhler et al. Powder Technol., 2017, 316, 492-499), the modeled axial mixing of fuel tracers shows good agreement with the experimental data. © 2020 American Chemical Society.

Fluidized beds

Fuels

Emulsification

Fuel gages

Tracers

Mixing

Wakes

Author

Anna Köhler

Energy Technology 3

David Pallarès

Chalmers, Space, Earth and Environment, Energy Technology

Filip Johnsson

Chalmers, Space, Earth and Environment, Energy Technology

Energy & Fuels

0887-0624 (ISSN) 1520-5029 (eISSN)

Vol. In Press

Enhanced performance in thermal conversion of biomass

Swedish Energy Agency, 2017-05-02 -- 2019-10-30.

Subject Categories

Applied Mechanics

Ocean and River Engineering

Fluid Mechanics and Acoustics

DOI

10.1021/acs.energyfuels.9b04194

More information

Latest update

5/29/2020