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Acoustic emission monitoring from a lab scale high shear granulator—A novel approach

Watson, N.J.; Povey, M.J.W.; Reynolds, G.K.; Xu, B.H.; Ding, Y.

Authors

N.J. Watson

M.J.W. Povey

G.K. Reynolds

B.H. Xu

Y. Ding



Abstract

A new approach to the monitoring of granulation processes using passive acoustics together with precise control over the granulation process has highlighted the importance of particle–particle and particle–bowl collisions in acoustic emission. The results have shown that repeatable acoustic results could be obtained but only when a spray nozzle water addition system was used. Acoustic emissions were recorded from a transducer attached to the bowl and an airborne transducer. It was found that the airborne transducer detected very little from the granulation and only experienced small changes throughout the process. The results from the bowl transducer showed that during granulation the frequency content of the acoustic emission shifted towards the lower frequencies. Results from the discrete element model indicate that when larger particles are used the number of collisions the particles experience reduces. This is a result of the volume conservation methodology used in this study, therefore larger particles results in less particles. These simulation results coupled with previous theoretical work on the frequency content of an impacting sphere explain why the frequency content of the acoustic emissions reduces during granule growth. The acoustic system used was also clearly able to identify when large over-wetted granules were present in the system, highlighting its benefit for detecting undesirable operational conditions. High-speed photography was used to study if visual changes in the granule properties could be linked with the changing acoustic emissions. The high speed photography was only possible towards the latter stages of the granulation process and it was found that larger granules produced a higher magnitude of acoustic emission across a broader frequency range.

Citation

Watson, N., Povey, M., Reynolds, G., Xu, B., & Ding, Y. (2014). Acoustic emission monitoring from a lab scale high shear granulator—A novel approach. International Journal of Pharmaceutics, 465(1-2), 262-274. https://doi.org/10.1016/j.ijpharm.2014.01.032

Journal Article Type Article
Acceptance Date Jan 21, 2014
Online Publication Date Feb 1, 2014
Publication Date Apr 25, 2014
Deposit Date Sep 16, 2018
Journal International Journal of Pharmaceutics (Deleted)
Electronic ISSN 1873-3476
Publisher Elsevier
Peer Reviewed Peer Reviewed
Volume 465
Issue 1-2
Pages 262-274
DOI https://doi.org/10.1016/j.ijpharm.2014.01.032
Public URL https://nottingham-repository.worktribe.com/output/1099749
Publisher URL https://www.sciencedirect.com/science/article/pii/S0378517314000532?via%3Dihub
PMID 00033367