Abstract: An apparatus and process for dehumidification of a compressed gas using a membrane cartridge dryer wherein substantially dry gas is provided upon process startup without requiring purging of the membrane cartridge. In the apparatus, a back pressure regulator valve controls the release of compressed gas to the dryer and a check valve controls the release of the dry gas from the dryer.

Abstract: A system for separating a portion of a first gas from a gaseous feed comprising a mixture of gases that is intermittently supplied to the system. The system comprises a membrane gas separator having at least one membrane through which the first gas permeates preferentially in comparison to other gases contained in the mixture. The separator is adpated to produce a nonpermeate gaseous product which is discharged from a nonpermeate gas side of the separator and in which the concentration of the first gas is lower than in the feed mixture. The system also includes a mechanism for supplying a gaseous purge stream to the separator when the feed mixture is not being supplied to the system. The concentration of the first gas is lower in the gaseous purge stream than in the feed mixture to purge residual amounts of the first gas contained in the membrane of the separator. The method of separating gases from an intermittently supplied feed is also disclosed.

Abstract: Nitrogen gas of high purity is produced from compressed air by contacting the air with a first gas membrane separator permitting oxygen to permeate therethrough selectively while restraining the passage of nitrogen. The nonpermeant gas is then brought into contact with a second gas membrane separator of similar construction. The use of the serially arranged separators provides nitrogen gas with very low levels of oxygen.

Abstract: A process has been developed for effectively purifying compressed air by removing water vapor, carbon dioxide and other impurities through the use of gas separation membrane systems. Gas separation membranes have been found which are capable of purifying air to a suitable level for operation of analytical instrumentation apparatus such as Fourier Transform Infrared analytical spectrometers and related instrumentation equipment. Impurities normally found in compressed air used in operation and purging of instrumentation devices include water vapor and CO.sub.2, which are strong absorbers of infrared radiation at wavelengths which interfere with analytical wavelengths and spectral regions commonly employed for analysis of a variety of organic and inorganic materials.

Abstract: This invention provides an apparatus and process for dehydrating gases, the apparatus comprised of uncoated, asymmetric membranes having controlled porosity. The membranes being formed of polymeric materials which have high transport selectivity for water vapor and sufficient porosity to provide adequate feed gas permeation sweep for the permeated water vapor ensuring conditions of continued effective dehydration. Uncoated asymmetric gas separation membranes have been found to be effective for dehydrating gases such as air, gases containing hydrocarbons, acid gases and admixtures of these gases. The membranes provided by the invention possess a unique combination of properties and characteristics which promote an effective process for the dehydration of gases.

Abstract: Process for recovering a permeating gas from a pair of gas streams one of which contains less than 30 percent of the permeating gas and the other of which contains more than 70 percent of the permeating gas wherein the other gas stream is brought into contact with a membrane through which a portion of the permeating gas passes. Non-permeating gases are mixed with the one stream and brought into contact with another membrane through which the permeating gas will pass, with the permeating gases from the membrane being combined and collected.