Scaling of continuous twin screw wet granulation |
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Authors: | Juan G. Osorio Ridade Sayin Arjun V. Kalbag James D. Litster Laura Martinez‐Marcos Dimitrios A. Lamprou Gavin W. Halbert |
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Affiliation: | 1. School of Chemical Engineering, Purdue University, Potter Engineering Center, West Lafayette, IN;2. EPSRC Centre for Innovative Manufacturing in Continuous Manufacturing and Crystallisation (CMAC), University of Strathclyde, Technology and Innovation Centre, Glasgow, U.K.;3. Strathclyde Institute of Pharmacy and Biomedical Sciences (SIPBS), University of Strathclyde, Glasgow, U.K. |
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Abstract: | Scaling rules were developed and tested for a continuous twin screw wet granulation process using three scales (11, 16, and 24 mm barrel diameter) of twin screw granulators (TSG). The distributive feed screw configuration used produced high porosity granules (50–60%) with broad bimodal size distributions, especially in the 16 and 24 mm TSGs. Three dimensionless numbers, Froude number (Fr), liquid‐to‐solid ratio (LSR), and powder feed number (PFN), were identified and their effect on granule size distribution (GSD), porosity and liquid distribution tested. Granule size increased with increasing LSR as expected. However, Fr and PFN had no significant effect on d10 or d50 and only a small effect on d90. In contrast, granulator scale had a strong effect on GSD, with d90 increasing almost linearly with barrel diameter. This is consistent with breakage of large granules being a dominant mechanism and directly controlled by the geometry of the screw. © 2016 American Institute of Chemical Engineers AIChE J, 63: 921–932, 2017 |
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Keywords: | twin screw granulation continuous manufacturing powders scaling |
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