Quantitative investigation on the effects of ice crystal size on freeze-drying: The primary drying step. Issue 2 (11th January 2022)

• Record Type: Journal Article
• Authors: Luo, Chun; Liu, Zhiqiang; Mi, Sha; Li, Longquan
• Is Part Of: Drying technology. Volume 40:Issue 2(2022)
• Page Start: 446
• Page End: 458
• Publication Date: 2022-01-11
• Subjects: Freeze-drying -- primary drying -- controlled nucleation -- ice crystal size; Drying -- Periodicals; Desiccation; 660.28426
• DOI: 10.1080/07373937.2020.1806865
• Languages: English
• ISSNs: 0737-3937

Abstract

Abstract: The size of ice crystals formed in the freezing process has a significant impact on the subsequent primary drying process. However, the effects have not been fully understood. The purpose of this study was to quantitatively investigate the effects of ice crystal size on water vapor concentration, temperature, and primary drying time. A mathematical model considering the effects of ice crystals size was proposed, and it was solved by Comsol Multiphysics. Results show that there is less water vapor in the products with larger ice crystals. Temperature is found to decrease initially, and larger ice crystals lead to a higher temperature in the dried zone while the lower temperature in the frozen zone. The primary drying process proceeds faster when the ice crystal size is large, and the decrement of primary drying time gets smaller when further increasing the size of ice crystals. This work could provide help for the optimization of freeze-drying.