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Mapping of regimes for the key processes in wet granulation: Foam vs. spray

Authors

  • Melvin X.L. Tan,

    1. Dept. of Chemical Engineering, Monash Advanced Particle Engineering Laboratory, Monash University, Clayton, VIC, Australia
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  • Karen P. Hapgood

    Corresponding author
    • Dept. of Chemical Engineering, Monash Advanced Particle Engineering Laboratory, Monash University, Clayton, VIC, Australia
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Correspondence concerning this article should be addressed to K. P. Hapgood at karen.hapgood@monash.edu.

Abstract

The evaluation of foam and spray granulation mechanisms and their performances in achieving uniform liquid distribution in a high-shear mixer-granulator is presented. A regime map is presented to describe the granulation mechanisms for the foam and spray systems. Foam and spray granulation are shown to successfully create granules of well-distributed moisture at the end of wet massing despite there was a deviation from the theoretical moisture content at the end of binder addition. In the wetting and nucleation regime, spray granulation involves drop penetration nucleation outside of the drop-controlled regime, whereas foam granulation operates favorably in the mechanical dispersion regime. For foam granulation, mechanical dispersion produces more uniform granule-size distributions below the overwetting limit. Spray granulation exhibits steady granule growth, whereas foam granulation shows induction granule growth followed by rapid granule growth. The regime map provides a basis to customize formulations and compare the different foam and spray granulation mechanisms. © 2013 American Institute of Chemical Engineers AIChE J, 59: 2328–2338, 2013

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