Overview of Sealing Methods

Membrane-to-module sealing methods are very important and have been addressed briefly above. Indeed, the functionality of the membrane module is predicated on the assumption that the feed stream is isolated from the permeate stream and the external atmosphere, and that the permeate stream is also isolated from the external atmosphere. This is especially true for a membrane module that will be used to purify hydrogen, since leaks could result in fire or explosion hazards. 

There are three different sealing methods that have been used to varying degrees of commercial success. They are  

As with soft metal gaskets, volatile components in the braze alloy (including phosphorus) should be avoided. A special subset of brazing is solid-state brazing, or intermetaUic diffusion. This occurs spontaneously, albeit slowly, when miscible metals are placed in direct contact. Examples of suitable metals for solid-state brazing to the membrane and module include copper, iron, silver, and nickel [7]. 

Scale-up from Laboratory Test-and-Evaluation Module to Commercial Membrane Module 

As we shift our interest from laboratory permeation cells to commercial membrane modules, our focus shifts from one of convenience to one of economics. The initial cost, or capital cost, of the membrane module is very important, but we cannot ignore the ongoing operating costs which include any and aU maintenance, as well as dedicated energy and utiUty costs. As mentioned previously, if the feed stream to the membrane module is sufficiently hot and suppUed at the 

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