55.
The possibility and applicability of the continuous membrane column concept to the membrane separation process of pervaporation has been demonstrated. It shows that a mixture of two or more liquids can be separated to a high degree without cascading several stages of individual pervaporation units. The degree of enrichment is unlimited in a continuous membrane column while a maximum limit exists in a conventional pervaporator. This new concept of membrane operation has been shown previously to give enhanced separations in gaseous systems without the expense and complexity of a multi-staged cascade.
The permeabilities of silicone rubber to ethanol—water and isopropanol—water mixtures were determined at 25 and 40°C as a function of concentration. Separation experiments were carried out in small membrane columns. Included were instances in which feed mixtures just below the azeotrope (because of the small size of the experimental column) were enriched beyond the normal azeotropic composition (0.89 mole fraction ethanol) on a continuous basis. Feed compositions at other levels were also investigated; for example, a feed at 0.50 mole fraction ethanol was continuously separated into two streams at 0.69 and 0.12 mole fraction ethanol Finally, a mathematical analysis has been developed which adequately describes capillary membrane pervaporation within a continuous membrane column configuration. 相似文献