In situ characterization of floc morphology by image analysis in a turbulent Taylor–Couette reactor

Authors

  • Mélody Vlieghe,

    1. Université de Toulouse; INPT, Toulouse, France
    2. CNRS, Laboratoire de Génie Chimique, Toulouse, France
    3. Université de Toulouse; INSA, Toulouse, France
    4. INRA, UMR792 Ingénierie des Systèmes Biologiques et des Procédés, Toulouse, France
    5. CNRS, Toulouse, France
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  • Carole Coufort-Saudejaud,

    1. Université de Toulouse; INPT, Toulouse, France
    2. CNRS, Laboratoire de Génie Chimique, Toulouse, France
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  • Christine Frances,

    1. Université de Toulouse; INPT, Toulouse, France
    2. CNRS, Laboratoire de Génie Chimique, Toulouse, France
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  • Alain Liné

    Corresponding author
    1. Université de Toulouse; INSA, Toulouse, France
    2. INRA, UMR792 Ingénierie des Systèmes Biologiques et des Procédés, Toulouse, France
    3. CNRS, Toulouse, France
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Abstract

Flocculation of bentonite was performed in a turbulent Taylor–Couette reactor under various shear rates. Image processing enabled to determine various morphological characteristics of individual flocs. Not only their mean values but also their distributions were studied under various hydrodynamic conditions. Relevant properties were selected. The temporal evolution of radius of gyration and circularity distributions was monitored during the flocculation process. Although size and shape are obviously correlated, this article points out that their dependency to hydrodynamics is different, showing that flocs of similar sizes produced under different hydrodynamic conditions exhibit different shapes. The sizes are calibrated by the turbulence as the double radius of gyration is close to Kolmogorov microscale, whereas the circularity seems correlated to the rotation speed. © 2014 American Institute of Chemical Engineers AIChE J, 60: 2389–2403, 2014

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