초록 ▼

An improved process for separating gases using a hollow fiber membrane on an intermittent basis is described. It has been found that if the pressure on the feed side of the membrane is maintained essentially constant or is allowed to vary slowly during operation and in the periods between operating

An improved process for separating gases using a hollow fiber membrane on an intermittent basis is described. It has been found that if the pressure on the feed side of the membrane is maintained essentially constant or is allowed to vary slowly during operation and in the periods between operating cycles the useful lifetime of the separation device is greatly extended. This process is particularly useful for the separation of air into oxygen- and nitrogen-enriched streams using hollow fibers melt spun from poly(4-methylpentene-1).

대표청구항 ▼

In a process for separating gases from a mixture using a device containing a hollow fiber membrane preferentially permeable to at least one component of the gas mixture wherein the separation process is intermittent and the device is to be used in at least 1000 operating cycles separated by periods

In a process for separating gases from a mixture using a device containing a hollow fiber membrane preferentially permeable to at least one component of the gas mixture wherein the separation process is intermittent and the device is to be used in at least 1000 operating cycles separated by periods of non-use, the improvement wherein the pressure on the feed stream side of the membrane is maintained essentially constant or is varied relatively slowly during cycling between periods of non-use and initiation of gas separation such that after 1000 cycles of operation the selectivity of the membrane at the operating flow rate and other conditions of operation is at least 20 percent greater than that of an otherwise identical membrane which has been subjected to a pressure change of 75 psi in a period of 15 seconds at the start of each cycle of operation.