Conceptual framework for model-based analysis of residence time distribution in twin-screw granulation

Ashish Kumar, Jurgen Vercruysse, Valerie Vanhoorne, Maunu Toiviainen, Pierre-Emmanuel Panouillot, Mikko Juuti, Chris Vervaet, Jean Paul Remon, Krist Gernaey, Thomas De Beer, Ingmar Nopens

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Twin-screw granulation is a promising continuous alternative for traditional batchwise wet granulation processes. The twin-screw granulator (TSG) screws consist of transport and kneading element modules. Therefore, the granulation to a large extent is governed by the residence time distribution within each module where different granulation rate processes dominate over others. Currently, experimental data is used to determine the residence time distributions. In this study, a conceptual model based on classical chemical engineering methods is proposed to better understand and simulate the residence time distribution in a TSG. The experimental data were compared with the proposed most suitable conceptual model to estimate the parameters of the model and to analyse and predict the effects of changes in number of kneading discs and their stagger angle, screw speed and powder feed rate on residence time. The study established that the kneading block in the screw configuration acts as a plug-flow zone inside the granulator. Furthermore, it was found that a balance between the throughput force and conveying rate is required to obtain a good axial mixing inside the twin-screw granulator. Although the granulation behaviour is different for other excipients, the experimental data collection and modelling methods applied in this study are generic and can be adapted to other excipients.
Original languageEnglish
JournalEuropean Journal of Pharmaceutical Sciences
Pages (from-to)25-34
Publication statusPublished - 2015


  • Residence time distribution
  • Flow modelling
  • Axial mixing
  • Stagnant zone
  • Wet granulation

Cite this

Kumar, A., Vercruysse, J., Vanhoorne, V., Toiviainen, M., Panouillot, P-E., Juuti, M., Vervaet, C., Remon, J. P., Gernaey, K., De Beer, T., & Nopens, I. (2015). Conceptual framework for model-based analysis of residence time distribution in twin-screw granulation. European Journal of Pharmaceutical Sciences, 71, 25-34.