On-line monitoring of a crystallization process

Authors

  • Patricia Mougin,

    Corresponding author
    1. Center for Molecular and Interface Engineering, Dept. of Mechanical and Chemical Engineering, Heriot-Watt University, Riccarton, Edinburgh EH14 4AS, U.K.
    Current affiliation:
    1. SSCI, Inc., 3065 Kent Avenue, West Lafayette, IN 47906
    • SSCI, Inc., 3065 Kent Avenue, West Lafayette, IN 47906
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  • Alistair Thomas,

    1. Center for Molecular and Interface Engineering, Dept. of Mechanical and Chemical Engineering, Heriot-Watt University, Riccarton, Edinburgh EH14 4AS, U.K.
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  • Derek Wilkinson,

    1. Center for Molecular and Interface Engineering, Dept. of Mechanical and Chemical Engineering, Heriot-Watt University, Riccarton, Edinburgh EH14 4AS, U.K.
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  • Graeme White,

    1. Center for Molecular and Interface Engineering, Dept. of Mechanical and Chemical Engineering, Heriot-Watt University, Riccarton, Edinburgh EH14 4AS, U.K.
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  • Kevin J. Roberts,

    1. Institute for Particle Science and Engineering, Dept. of Chemical Engineering, University of Leeds, Leeds LS2 9JT, U.K.
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  • Norbert Herrmann,

    1. Malvern Instruments Ltd., Enigma Business Park, Malvern, Worcestershire, WR14 1XZ, U.K.
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  • Robert Jack,

    1. Malvern Instruments Ltd., Enigma Business Park, Malvern, Worcestershire, WR14 1XZ, U.K.
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  • Richard Tweedie

    1. Malvern Instruments Ltd., Enigma Business Park, Malvern, Worcestershire, WR14 1XZ, U.K.
    Current affiliation:
    1. Hasbro Europe, Technology Development, 2 Roundwood Ave., Stockley Park, Uxbridge UB11 1AZ, U.K.
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Abstract

The application of ultrasonic spectroscopy for particle-size measurements was investigated during the batch crystallization of (L)-glutamic acid α-polymorph from an aqueous solution. The technique, based on measurements of the attenuation of ultrasonic waves through the suspension, was applied using a prototype ultrasonic spectrometer with a flow-through cell. High-precision measurements of ultrasonic attenuation in the frequency range 7–110 MHz were performed, the deconvolution of which enabled in-process measurement of crystal size distribution and solid concentration throughout the crystallization process. In addition to evincing secondary nucleation, growth and crystal breakage on-line in real time, the experimental results were used to obtain kinetic parameters essential for process design, including secondary nucleation rate and growth rate.

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