| 摘要 |
<p>This invention uses a first or roughing stage to remove the bulk of moisture and a second or polishing stage to complete the drying. The first stage can use a relatively small membrane area and a relatively low quality purge gas whereas the second stage can use a large membrane area and high quality purge gas, such as some product back purge. The arrangement provides efficient usage of available high quality purge gas, such as product, while minimizing product contamination. This two stage purging arrangement is especially attractive for those processes or systems where multigrade purge gases are available. <IMAGE></p> |
