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The influence of particle size and density on the radial gas mixing in the dilute region of the circulating fluidized bed
Author(s) -
Mastellone Maria Laura,
Arena Umberto
Publication year - 1999
Publication title -
the canadian journal of chemical engineering
Language(s) - English
Resource type - Journals
SCImago Journal Rank - 0.404
H-Index - 67
eISSN - 1939-019X
pISSN - 0008-4034
DOI - 10.1002/cjce.5450770207
Subject(s) - mixing (physics) , dispersion (optics) , péclet number , tracer , turbulence , mechanics , particle (ecology) , range (aeronautics) , particle density , fluidized bed combustion , fluidization , particle size , materials science , thermodynamics , chemistry , fluidized bed , physics , optics , nuclear physics , geology , oceanography , quantum mechanics , volume (thermodynamics) , composite material
A cold model of a CFB, having a 0.120m ID, 5.75m high riser, was operated at a superficial gas velocity of 6m/s and at average solids mass fluxes varying in the range between 16 and 55kg/sm 2 . A stream of carbon dioxide was injected continuously at a fixed position along the riser axis and used as tracer gas. Three solids, belonging to groups A and B of Geldart's classification, were selected in order to investigate separately, the effect of particle size and density on the radial mixing of the gas phase. The intensity of radial gas dispersion reduced when larger or heavier particles were used. The differences in the values of radial dispersion coefficient and Peclet number were explained, taking into account the role of the particle size with respect to the scale of gas turbulence.