Transition to turbulent fluidization in a binary solids fluidized bed

Authors

  • D. Bai,

    1. Department of Biological & Chemical Engineering, Gunma University, Kiryu, Gunma 376, Japan
    Current affiliation:
    1. Department of Chemical Engineering, The University of British Columbia, 2216 Main Mall, Vancouver, B. C. V6T 1Z4, Canada
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  • Y. Masuda,

    1. Department of Biological & Chemical Engineering, Gunma University, Kiryu, Gunma 376, Japan
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  • N. Nakagawa,

    1. Department of Biological & Chemical Engineering, Gunma University, Kiryu, Gunma 376, Japan
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  • K. Kato

    Corresponding author
    1. Department of Biological & Chemical Engineering, Gunma University, Kiryu, Gunma 376, Japan
    • Department of Biological & Chemical Engineering, Gunma University, Kiryu, Gunma 376, Japan
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Abstract

This paper presents a study on the transition velocity from bubbling to turbulent fluidization in a binary solids fluidized bed. Experiments were carried out with two kinds of binary solids mixtures with FCC as fine particles and silica sands as coarse particles. The onset velocity to turbulent fluidization, Uc, determined by the measurement of pressure fluctuations, was found to increase with increasing the fraction of coarse/heavy solids. By introducing an equivalent particle diameter and an equivalent particle density, the results obtained in this study can properly be described by a general correlation of Uc proposed by Cai and co-workers (1989) for mono-density particles with relatively narrow size distribution.

Abstract

On présente dans cet article une étude sur la vitesse de transition entre la fluidisation bouillonnante et turbulente dans un lit fluidisé de solides binaires. Les expériences ont été menées avec deux sortes de mélanges solides binaires avec des FCC comme particules fines et des sables de silice comme particules grossières. On a trouvé que la vitesse seuil de fluidisation turbulent, Uc, déterminée par la mesure des fluctuations de pression, augmentait avec la fraction des solides grossiers ou lourds. En introduisant un diamètre et une densité de particules équivalents, on peut correctement décrire les résultats obtenus dans cette étude par la corrélation générate proposée par Cai et ses collaborateurs (1989) pour des particules monodensité ayant une distribution de tallies relativement étroite.

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