The evolution of pellet size and shape during spheronisation of an extruded microcrystalline cellulose paste
Chemical Engineering Research and Design
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Lau, C., Yu, Q., Lister, V., Rough, S., Wilson, I., & Zhang, M. (2014). The evolution of pellet size and shape during spheronisation of an extruded microcrystalline cellulose paste. Chemical Engineering Research and Design https://doi.org/10.1016/j.cherd.2014.01.018
The process by which cylindrical rods of soft solid paste extrudate are converted into round pellets on a spheroniser (Marumeriser™) plate was studied by interrupting spheronisation tests and measuring the size and shape of the pellets. Batches of 20 identical rods (20 mm long, 3 mm diameter) generated by ram extrusion of 47 wt% microcrystalline cellulose/water paste were spheronised at rotational speeds, ω, between 1200 rpm and 1800 rpm on a laboratory spheroniser. The time to complete spheronisation was found to scale with ω−3.6, which was close to the ω−3dependency predicted by a simple collision model. Breakage occupied the first 10% of the process duration: rounding off was the rate-determining step. The evolution of pellet shape was classified into five stages, the duration of which was found to scale with spheronisation time. Pellet shape, quantified by aspect ratio, circularity, shape and angularity factors presented by Sukumaran and Ashmawy (2001), showed similar behaviour for all ω studied. A phenomenological model is proposed which identifies different routes for small and large rod breakage products.
External DOI: https://doi.org/10.1016/j.cherd.2014.01.018
This record's URL: https://www.repository.cam.ac.uk/handle/1810/245304