Thin film heat exchangers

In another method of tempering, soHd chocolate shavings are added as seed crystals to Hquid chocolate at 32—33°C. This is a particularly good technique for a small confectionery manufacturer, who does not produce his own chocolate. However, the shavings are sometimes difficult to disperse and may cause lumps in the finished product (20). Most companies use continuous thin-film heat exchangers for the tempering process. 

Figure 16.13. MWB (Metallwerk Buchs) batch recirculating crystallizer, with freezing on and melting off insides of thin film heat exchanger tubes adaptable to multistage processing without external solids handling [Miitzenberg and Saxer, 1971).

Diffusion/conduction path reduction Heat and mass transfer Thin film heat exchangers Membrane processes Miniaturization Catalysis... 

The polymer can easily be recovered by simple vacuum filtration or centrifugation of the polymer slurry. This can be followed by direct conversion of the filter cake to dope by slurrying the filter cake in chilled solvent and then passing the slurry through a heat exchanger to form the spinning solution and a thin-film evaporator to remove residual monomer. 

In any type of packed tower, the liquid or internal reflux drips through the packing, and forms a thin film of liquid on the surface of the packing. Vapor percolates up through the packing, and exchanges heat and molecules with the thin film of liquid on the surface of the packing. 

A continuous-process device for rapidly changing the temperature of a liquid system. Liquid enters the device, is spread in a thin film over a heat-exchanging surface, is then removed from the surface by wall scrapers, and then exits the device through an outlet. 

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