| The membrane separation technology has been achieving the rapid progress for the near decades. As one of the newest developments on membrane separation, pervaporation is a promising technique for the separation of liquid mixtures, such as azeotropic and isomeric mixtures, which are difficult or impossible to separate by conventional technology. In many cases, due to volatile feature of the organic compounds, the temperature treatment induces irreversible chemical changes or simple escape of key aromas and therefore, drastically decreases the quality of the final product. Compared to conventional separation processes, pervaporation offers certain advantages; it has high separation efficiency even at mild process conditions. The paper has mainly studied the pervaporation performance of a novel silicone rubber compound membrane in the concoctive aqueous ethanol solution and the Chinese spirits with a membrane bioreactor system (MBR), and the influence of operation parameters on the membrane separation performance. This paper consists of the following three parts:Firstly, a summarized review was done for the present situation, the application and the prospect about the membrane separation and particularly pervaporation technology. The elementary theory and features about the pervaporation technology was introduced. On the basis of this review, a research proposal was presented.Secondly, in accordance with the setup of the MBR and the features of the composite silicone rubber membrane, a principal theoretical analysis was carried out for the pervaporation process. Some details on the membrane materials, structures and forming techniques were analyzed. Then, effects of some process parameters on the membrane separation performance were discussed.Finally, The flavor compositions in 52oand 72o Chinese spirits were separated by pervaporation using a novel plate composite silicone rubber membrane at 30℃ and 1325Pa downstream pressure, respectively. The results suggested that the good separation performance for flavor compositions and the good stability in high ethanol concentration were achieved by the membrane, for example, the separation rate of five kinds of ester (except for Ethyl Lactate ) and acetal in original wine are over 86 %, the membrane also showed a good separation characteristics for fusel, and the separation rate of acetaldehyde is over 70 %. The membrane showed the average total permeation flux in 52o and 72o Chinese spirits were approximately 2070g/m2·h and 2330 g/m2·h, the separation factor for ethanol and water reached the value of 4 .9 and 3.1, respectively. The permeated liquor collected in the downstream membrane tasted much better than the original liquor. Then, in order to learn the influence of temperature on the separation characteristics, the flavor compositions in a new type of 50o Chinese spirits were separated by pervaporation at 30℃ ,35℃and 40℃,1325Pa downstream pressure, respectively. The results suggested that the membrane had excellent separation performance for the flavor compositions and good stability in these liquors with high concentration ethanol, too. For example, separation efficiencies for five kinds of esters (except ethyl Lactate) and acetal in the original liquor are 100%. The membrane also behaved with a good separation for fusel, and removal efficiency over 87 % for acetaldehyde. Recombining the separated spirits, we got the higher quality spirits than original spirits. The membrane had average total permeation fluxes of 2297g/m2·h, 2753 g/m2·h and 3539 g/m2·h and separation factors of 5.22, 5.22 and 5.32 for ethanol-water, with this kind of Chinese spirits, at 30℃, 35℃and 40℃,respectively. Through above a series of studies,it is possible to develop application technology with pervaporation with the composite PDMS membrane, such as for production of good-taste Chinese spirits and Brandy, and for separation of natural aromas and fermenting volatile organic compounds. We also provided some experimental basis and experience for further work of P...
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