Freeze-Drying Mechanisms and Drying Rates Under Various Drying Conditions
Freeze-drying rates of relatively homogeneous frozen materials and frozen particles in a shallow tray by radiative and conductive heating are studied both experimentally and theoretically. The drying mechanism of frozen materials of which initial ice content is less than 1.0 is quite different from the flat plane sublimation, which was found previously by one of the authors to become unstable under some conditions. The total drying times under various conditions are discussed for this kind of frozen materials and also for a packed bed of frozen particles using dimensionless heat and mass transfer equations to obtain some information for shorter drying time.
KeywordsPermeability Porosity Tray
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- 1.Fisher, F.R., Freeze-Drying of Foods, Natl. Acad. Sci.-Natl. Res. Council, Washington D.C. (1958)Google Scholar
- 2.Sandall, O.C., King, C.J. and Wilke, C.R., AI ChE Journal, Vol. 13, 428 (1967)Google Scholar
- 3.Margaritis, A. and King, C.J., Chem. Eng. Prog. Sympo. Ser., Vol. 67, 112 (1970)Google Scholar
- 5.Asaeda, M. and Toei, R., Mechanism of Freeze-Drying of Porous Bodies by Conductive Heat Transfer, 18th ASME/AIChE National Heat Transfer Conf., San Diego, ASME Paper 79HT86 (1979)Google Scholar