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dc.contributor.advisorPugsley, Todden_US
dc.creatorWormsbecker, Michaelen_US
dc.date.accessioned2008-11-21T12:46:29Zen_US
dc.date.accessioned2013-01-04T05:08:57Z
dc.date.available2009-11-25T08:00:00Zen_US
dc.date.available2013-01-04T05:08:57Z
dc.date.created2008en_US
dc.date.issued2008en_US
dc.date.submitted2008en_US
dc.identifier.urihttp://hdl.handle.net/10388/etd-11212008-124629en_US
dc.description.abstractFluidized bed dryers (FBDs) are used in the pharmaceutical industry to remove excess moisture from granule prior to tablet formation. As granule moisture content is reduced from its initial to final state, the velocity required to fully fluidize the granule decreases and the bed voidage decreases. The change in these fluidization properties are attributed to the decrease in the interparticle force load created by a reduction in liquid bridging as moisture is removed. During constant velocity drying, these fluidization properties result in a bubbling fluidization state, which evolves into a bubble coalescing regime as drying proceeds. This behaviour was identifiable using pressure fluctuation time-series analysis techniques. Distributor design studies using dry and wet granule in a conical fluidized bed suggest that the punched plate design limits bubble coalescence when compared to the perforated plate and Dutch weave mesh designs. Furthermore, the Dutch weave results in extensive segregation, which is undesirable from a fluidization perspective. Local drying hydrodynamic measurements using x-ray densitometry found that the punched and perforated plates generate a centralized bubbling core region during drying with a defluidized bed periphery. This fluidized core region grows as drying proceeds until the defluidized region disappears. Under the same operating conditions, a porous plate distributor creates extensive channelling and defluidization across the entire bed cross-section during the constant rate period of drying. These poor fluidization characteristics are a result of the porous plate introducing the gas into the bed as a fine dispersion. Lastly, the hydrodynamics associated with the conical vessel geometry improves the circulation and mixing patterns in fluidized bed dryers. This is especially the case in the entry region of the conical bed where the high inlet gas velocity prevents defluidization around the periphery of the bed. The straight walled geometry of the cylindrical bed resulted in defluidization in this area. As a result, the hydrodynamics associated with bubbling differ significantly between the geometries over the course of drying.en_US
dc.language.isoen_USen_US
dc.subjecthydrodynamicsen_US
dc.subjectparticle characterizationen_US
dc.subjectdistributor designen_US
dc.subjectvessel geometryen_US
dc.subjectdryingen_US
dc.subjectfluidizationen_US
dc.titleStudy of hydrodynamic behaviour in a conical fluidized bed dryer using pressure fluctuation analysis and X-ray densitometryen_US
thesis.degree.departmentChemical Engineeringen_US
thesis.degree.disciplineChemical Engineeringen_US
thesis.degree.grantorUniversity of Saskatchewanen_US
thesis.degree.levelDoctoralen_US
thesis.degree.nameDoctor of Philosophy (Ph.D.)en_US
dc.type.materialtexten_US
dc.type.genreThesisen_US


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