Bubble size and radial gas hold-up distributions in a slurry bubble column using ultrafast electron beam X-ray tomography

Authors

  • Swapna Rabha,

    Corresponding author
    1. Experimental Thermal Fluid Dynamics, Institute of Fluid Dynamics, Helmholtz-Zentrum Dresden-Rossendorf, Dresden, Germany
    • Correspondence concerning this article should be addressed to S. Rabha at s.rabha@hzdr.de.

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  • Markus Schubert,

    1. Experimental Thermal Fluid Dynamics, Institute of Fluid Dynamics, Helmholtz-Zentrum Dresden-Rossendorf, Dresden, Germany
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  • Michael Wagner,

    1. Experimental Thermal Fluid Dynamics, Institute of Fluid Dynamics, Helmholtz-Zentrum Dresden-Rossendorf, Dresden, Germany
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  • Dirk Lucas,

    1. Experimental Thermal Fluid Dynamics, Institute of Fluid Dynamics, Helmholtz-Zentrum Dresden-Rossendorf, Dresden, Germany
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  • Uwe Hampel

    1. Experimental Thermal Fluid Dynamics, Institute of Fluid Dynamics, Helmholtz-Zentrum Dresden-Rossendorf, Dresden, Germany
    2. AREVA Endowed Chair of Imaging Techniques in Energy and Process Engineering, Dresden University of Technology, Dresden, Germany
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Abstract

Gas hold-up and bubble size distribution in a slurry bubble column (SBC) were measured using the advanced noninvasive ultrafast electron beam X-ray tomography technique. Experiments have been performed in a cylindrical column (DT = 0.07 m) with air and water as the gas and liquid phase and spherical glass particles (dP = 100 μm) as solids. The effects of solid concentration (0 ≤ Cs ≤ 0.36) and superficial gas velocity (0.02 ≤ UG ≤ 0.05 m/s) on the flow structure, radial gas hold-up profile and approximate bubble size distribution at different column heights in a SBC were studied. Bubble coalescence regime was observed with addition of solid particles; however, at higher solid concentrations, larger bubble slugs were found to break-up. The approximate bubble size distribution and radial gas hold-up was found to be dependent on UG and Cs. The average bubble diameter calculated from the approximate bubble size distribution was increasing with increase of UG. The average gas hold-up was calculated as a function of UG and agrees satisfactorily with previously published findings. The average gas hold-up was also predicted as a function of Cs and agrees well for low Cs and disagrees for high Cs with findings of previous literature. © 2012 American Institute of Chemical Engineers AIChE J, 59: 1709–1722, 2013

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