| 摘要 |
<p>1372282 Freeze concentration STRUTHERS SCIENTIFIC & INTERNATIONAL CORP 4 Jan 1973 [5 Jan 1972] 364/72 Heading B1G [Also in Division A2] Aqueous solutions, e.g. of coffee, tea or orange juice, are concentrated by a two stage process comprising injecting a cooling medium into the solution to form ice therein, evaporating the medium from the partially concentrated solution and ice slurry, separating the ice from the slurry and further concentrating the solution by indirect heat exchange separating the ice therefrom and recovering the concentrated solution. The process may be effected continuously. The cooling medium may be butane or and this medium may, in the process be recovered and used in the indirect heat exchange crystallizer. The final product may be frozen and freeze dried. In the first stage, i.e. direct contact cooling, frothing or foam may occur which may be reduced by spraying the foam with a readily evaporating cold liquid, or providing a heat exchanger in the upper part of the crystallizer and maintaining it at a temperature just a few degrees below that of the liquid and foam. In the flow diagram shown the solution to be concentrated is fed by pipe 10 to feed tank 11 and from there by pipe 12 to a direct contact crystallizer 13, which has an agitator paddle rotor 14, driven by motor 15 and a sparging pipe 18 fed with the liquid cooling medium, e.g. butane. The medium leaves the crystallizer 13, is compressed by main compressor 22, fed to direct contact condenser 24 where the refrigerant is condensed while the ice is melting. The medium is then returned to tank 20 as a liquid via compressor 25 and condenser 26. The ice from the slurry of ice and concentrate is separated in centrifuge 29, and fed by pipe 30 to tank 31 from where it is pumped to condenser 24. The concentrate from 29 passes by pipe 40 to tank 41, and then by pipe 42 to the indirect heat exchanger crystallizer 44 from where the ice and cencentrate is separated in centrifuge 48. The ice from 48 is recycled by pipe 52 to the feed tank 35 and the concentrate passed to production tank 50.</p> |
