Freeze intensification

Methyl- and dimethylnaphthalenes are contained in coke-oven tar and in certain petroleum fractions in significant amounts. A typical high temperature coke-oven coal tar, for example, contains ca 3 wt % of combined methyl- and dimethylnaphthalenes (6). In the United States, separation of individual isomers is seldom attempted instead a methylnaphtha1 ene-rich fraction is produced for commercial purposes. Such mixtures are used for solvents for pesticides, sulfur, and various aromatic compounds. They also can be used as low freezing, stable heat-transfer fluids. Mixtures that are rich in monomethyinaphthalene content have been used as dye carriers (qv) for color intensification in the dyeing of synthetic fibers, eg, polyester. They also are used as the feedstock to make naphthalene in dealkylation processes. PhthaUc anhydride also can be made from m ethyl n aph th al en e mixtures by an oxidation process that is similar to that used for naphthalene. 

Ditchev, S. and Richardson, R, Intensification of freezing, in Oliveira, F.A.R. and Oliveira, J.C., (eds.). Processing foods quality optimisation and process assessment, CRC Press, Boca Raton, Florida, 1999, 145-162. 

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. 

Thermal intensification, reduction in pasteurization and cooking time rapid heating high potential for hybrid processing (with hot air vacuum, osmotic, freezing, IR/RF)... 

Unfortunately there is no equivalent to microwaves (for heating) that allows us to rapidly cool or freeze foodstuffs Intensification of heat and mass transfer during cooling processes, if feasible, could help to overcome the inertia of transfer through solidifying masses. However, some work at the renowned Odessa State Academy of Food Technologies in the Ukraine on the use of acoustic fields at around 22 kHz has been shown to aid the concentration and fractionation of food solutions by intensifying heat and mass transfer in the system boundary layer, Burdo et al. (2008). 

The idea of the intensification of freeze drying by introducing a moisture-adsorbing substance into the drying chamber is shown schematically in Figure 39.20... 

Chapter 3 Superheated steam drying of foods and biomaterials Chapter 4 Intensification of fluidized-bed processes for drying and formulation Chapter 5 Intensification of freeze-drying for the pharmaceutical and food industries... 

A more detailed treatment of the application of ultrasound is provided in Chapter 8, along with a discussion of the principles of generation and transmission of ultrasound energy to the material to be treated. It is pointed out that power ultrasound can be used to assist both, liquid-solid processes, such as brine treatment, and drying. The acoustic field is shown to enhance, by a number of mechanisms, both, the external and the internal mass transfer when combined with hot air or atmospheric freeze drying of vegetables and fruits. The more porous the material, and the lower the permissible temperature and gas velocity, the higher is the intensification that can be reached by application of power ultrasound. 

Intensification of Freeze-Drying for the Pharmaceutical and Food Industries... 

Intensification of Freeze-Dryingforthe Pharmaceutical and Food Industrie mass flux drying... 

Intensification of Freeze-Drying forthe Pharmaceutical and Food Industries 800... 

Process Intensification in Vacuum Freeze-Drying of Liquids 1139... 

Intensif cation of Freeze-Dryingjorthe Pharmaceutical and Food Industries 5.3.2... 

In freeze-drying, process intensification involves the development of new technologies that can reduce consumption costs and lead the way towards uniformity in end-product quality. 

The control of freezing can also benefit process intensification, as this stage can impact the product structure and hence modify the product resistance to mass transfer. Various groups have also claimed that it can improve batch uniformity. In this chapter, the various methods proposed to date to regulate ice nudeation have been briefly described, and an example of application to a real case provided. 

Elia, A. M Barresi, A. A., 1998. Intensification of transfer fluxes and control of product properties in freeze-drying. Chem. Eng. Process. 37(5) 347-358. 

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