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Gas–solid fluidization in a centrifugal field
Author(s) -
Qian GuiHua,
Bágyi István,
Burdick Ian W.,
Pfeffer Robert,
Shaw Henry,
Stevens John G.
Publication year - 2001
Publication title -
aiche journal
Language(s) - English
Resource type - Journals
SCImago Journal Rank - 0.958
H-Index - 167
eISSN - 1547-5905
pISSN - 0001-1541
DOI - 10.1002/aic.690470509
Subject(s) - fluidization , fluidized bed , group (periodic table) , centrifugal force , mechanics , particle (ecology) , materials science , thermodynamics , chemistry , physics , flow (mathematics) , geology , organic chemistry , oceanography
Abstract The nature of fluidization and the behavior of particles in a centrifugal field are discussed. Powders are classified into four groups (A, B, C, and D) following Geldart based on their fluidization behavior. A simple general model, agreeing with conventional fluidized beds and usable for variable “g,” is proposed to determine the transition boundary between group A and C particles. The general model for conventional fluidized beds by Foscolo and Gibiloro was used to determine the boundary between group A and B particles, and the semiempirical equation of Molerus for the boundary between group B and D particles in a centrifugal field. Theoretical analysis showed that group A particles can shift to group B, and group C particles can shift to group A under a centrifugal force. Therefore, certain group C particles can be fluidized in rotating fluidized beds. For very high “g,” however, such particles shift to group D and cannot be fluidized. Experiments in a horizontal rotating fluidized bed under different “g” forces to check the theoretical analysis confirmed that Geldart group C particles (7 μm alumina), which cannot be fluidized in a conventional fluidized bed, can fluidize in a rotating fluidized bed operating at a sufficiently high rotating speed to shift them into group A or B. Similarly, in a series of experiments in a rotating fluidized bed, group A particles behaved as group B.