| 摘要 |
A spiral-wound pervaporation module, designed to achieve optimum permeate flow throughput. The module is of conventional design and construction, in that it incorporates membrane envelopes, within and between which are channels through which the feed and permeate streams flow. The feed and permeate channels are created by spacers on the feed and permeate sides of the membrane layers. The module is unconventional in that the permeate spacer is tailored for optimum permeate flow throughput. The tailoring is based on the discovery that the total permeate flow throughput from a module passes through a maximum as the resistance to vapor transport of the permeate spacer material is progressively decreased. The resistance to vapor transport along the permeate channel is kept below a value at which it has a significant adverse effect on the membrane flux and the membrane separation properties, yet at the same time the total module throughput is within an optimum range. When modules in accordance with the invention are made, the increase in throughput per unit membrane area that is obtained more than compensates for the loss in membrane area brought about as a result of the use of a thicker permeate spacer. The modules are particularly advantageous for containing high-flux, high-separation membranes, and for low-pressure pervaporization processes.
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