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Aerated vibrofluidization of silica nanoparticles
Author(s) -
Nam Caroline H.,
Pfeffer Robert,
Dave Rajesh N.,
Sundaresan Sankaran
Publication year - 2004
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.10237
Subject(s) - fluidization , agglomerate , elutriation , mechanics , pressure drop , materials science , aeration , range (aeronautics) , superficial velocity , fluidized bed , chemistry , mineralogy , thermodynamics , composite material , flow (mathematics) , physics , organic chemistry
Vigorous homogeneous fluidization of 12‐nm silica particles was easily achieved by coupling aeration with vibration. Vibration (with frequency in the range of 30 to 200 Hz, and vibrational acceleration in the range of 0 to 5 g) was found to be necessary to achieve smooth fluidization. The minimum fluidization velocity, defined as the lowest gas velocity at which the pressure drop across the bed reaches a plateau, was approximately 0.3–0.4 cm/s, and essentially independent of the vibrational acceleration. However, the bed expanded almost immediately after the air was turned on, reaching bed expansions of three times the initial bed height or higher. Thus the bed appeared to exhibit a fluidlike behavior at velocities much lower than the minimum fluidization velocity. Fluidization of nanoparticles was achieved as a result of the formation of stable, relatively large, and very porous agglomerates. Practically no bubbles or elutriation of particles was observed. A fractal analysis combined with a modified Richardson–Zaki approach is proposed for prediction of agglomerate size and voidage. © 2004 American Institute of Chemical Engineers AIChE J, 50: 1776–1785, 2004