Vacuum freeze-drying

Kochs, M., Korber, Ch., Nunner, B., Fleschel, I. The influence of the freezing process on vapor transport during sublimation in vacuum-freeze-drying. Journal of Heat and Mass Transfer 34, p. 2395-2408, 1991... 

J Wolff, E., Gibert, H. Rudolf, F Vacuum freeze-drying kinetics and modeling of a liquid in a vial. Chem. Eng. Process., 25 (3), p. 153-158, 1989... 

Kemp, S. D. in Cremer, H. W. and Davies, T. (eds.) Chemical Engineering Practice, 6, (Butterworth, London, 1958) 567-600. Sublimation and vacuum freeze drying. 

Chambers, H. H. Trans. Inst. Chem. Eng. 27 (1949) 19. Vacuum freeze drying. 

Hammami, C., Rene, F., Marin, M. Process-quality optimization of the vacuum freeze-drying of apple slices by the response surface method, bit. J. Food Sci. Technol. 34,145-160,1999... 

Examples of mass transfer under high vacuum are distillation of thermally unstable organic compounds, high-vacuum freeze drying, vacuum concentration of fruit juices, vacuum drying of coffee concentrate, vacuum purification of molten metals, etc. The mechanism of mass transfer in the concentration of fruit juices can be adequately described by the Gilliland-Sherwood equations (Gl), since the mean free path is negligible relative to the dimensions of the vessel at the pressures used. These equations show that the mass transfer coefficient is inversely proportional to the pressure. By extrapolation to very low pressures, it should be possible... 

Shi, A. Li, D. Wang, L. Adhikari, B. Rheological properties of suspensions containing cross-linked starch nanoparticles prepared by spray and vacuum freeze drying methods. Carbohydr. Polym. 2012, 90 (4), 1732-1738. 

The investigations by Dunoyer and Larouse [42] and Woodard [73] indicated furthermore that atmospheric freezedrying rates of small particles can be equivalent to those of vacuum freeze drying. They provided an economic analysis of the energy costs for moisture removal as well. 

Lebedev, D.P. and Bykhowskii, B.N. 2001. Method of intensification of vacuum freeze-drying and development of a new apparatus for continuous operation. J. Industrial Heat Eng., 23(l-2) 67-75. 

Loch-Bonazzi et al. [33] evaluated the quality of mushrooms dried by various processes such as hot air, vacuum, freeze-drying in an adsorbent fluidized bed and vacuum freeze-drying. Results of their study indicated that vacuum freeze-dried products were of superior quality in... 

Coal, oil, natural gas, electric energy, waste materials, and solar energy High vacuum (freeze drying), vacuum, atmospheric pressure, and high pressure From 10 kg/h to >100 t/h... 

Kemp, S.D. (1958) Sublimation and vacuum freeze drying. In Chemical Engineering Practice, Vo. 6,H.W. CremerandT. Davies (eds.), Butterworths, London, 567-600. 

Zhang X, Zhao HZ, Ma Q, Li XW, Wang HZ, Zhang WJ (2005) Preparation of spinel nanopowder with vacuum freeze drying. Rare Metal Mater Eng 34 78-81... 

Because of the internally controlled mass transfer, drying times for atmospheric freeze-drying are longer than for the vacuum freeze-drying. The difference in drying time increases with particle size (thickness). Thus, for 5-mm-thick particles, about 2 hours are needed to reduce the moisture content from 4 kg/kg to 2 kg/kg in the vacuum process, whereas 6 hours are required... 

Donsi, G, Ferrari G, Matteo, PDi. Atmospheric and vacuum freeze-drying kinetics of shrimps. Proc. 12 Inti. Drying Symposium (IDS 2000), Amsterdam The Netherlands, Paper 279, 2000. 

Long-term processes (1 h< < 1 d). Examples Rotary drum drying, vacuum tumbling drying, vacuum freeze drying, fractionation crystallization. 

Annstrong, J. G., 1980. Use of the capadtance manometer gauge in vacuum freeze-drying. J. Parent. Drug Assoc. J4 473 3. 

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