Abstract: An adsorption process and system for the selective adsorption of a more readily adsorbable component, such as nitrogen, as from air or other feed gas mixture is carried out using a composite adsorbent bed containing different adsorbent materials positioned in separate zones in which the temperature conditions favor adsorption performance of the particular adsorbent material under applicable processing conditions in each zone. A method for the selection of the adsorbent materials is based on Adsorption Figure of Merit values.

Abstract: A pressure swing adsorption process for the recovery of oxygen from air improves upon a prior art process by depressurizing the adsorbent bed within an adsorbent vessel to an intermediate pressure by releasing void space gas from the product end of the vessel to a low purity oxygen tank while concurrently evacuating the adsorbent vessel from the feed end. This action enables an increased speed of depressurization and a reduction of the cycle time. Further, the adsorbent bed is repressurized to an intermediate pressure from the product outlet end with gas from the low purity oxygen tank, while concurrently pressurizing the adsorbent vessel from the input feed end. This action increases the load time fraction for a feed/vacuum blower. Further, oxygen is introduced to the product end of the adsorbent bed vessel from a high purity oxygen tank (which provides product to downstream applications) while concurrently, air is introduced to the feed end of the adsorbent bed within the vessel.

Abstract: Large vacuum pressure swing adsorption-oxygen plants are employed with four adsorption vessels, two air compressors, two vacuum pumps and an oxygen surge tank, operated on a (two) two-bed processing system basis. One two-bed system is offset from the other by one half of one half processing cycle. Reduced power and capital cost savings are achieved.

Abstract: This invention is directed towards an improved process for the selective gas phase oxidation of a organic reactant using a metal oxide redox catalyst, wherein the organic reactant and air feeds are at a substantially continuous level, the improvement comprising adding a fluctuating flow of oxygen at alternating relatively high and relatively low levels. The invention also teaches means by which a gas may be provided to a reaction process on a fluctuating basis.

Abstract: Anisotropic fluid separation membranes having an integral discriminating layer are formed from blends of two types of polyimides. The first type is a phenylindane containing polyimide. The second type consists of polyimides formed from the reaction of benzophenone tetracarboxylic dianhydride (BTDA) and optionally pyromellitic dianhydride (PMDA), with toluene diisocyanate (TDI) and/or 4,4'-methylene-bis-phenylisocyanate (MDI). The ratio of Type 1 polymer to Type 2 polymer is 1 or less. The blend membranes are particularly useful for gas separation.

Abstract: Gas separation membranes are prepared from sulfonated polyimides exhibiting desirable gas separation characteristics, combined with good film-forming properties and desirable solubility characteristics.

Abstract: Zeolites containing mixed cations are conveniently prepared by saturating the zeolites with the less strongly held cation, and then injecting the more strongly held cations in a pulse in a recirculating brine solution containing the less strongly held cation. The more strongly held cation is thus exchanged with the less readily held cation on the surface of the zeolite, after which the particles are allowed to equilibrate, with the distribution of the cations within the particles approaching an equilibrium value.

Abstract: Segregated external gas storage tanks are used to store gases of varying purity for use in the purge and pressure equalization and product repressurization steps of pressure swing adsorption operations, thereby enabling the bed size factor and the power requirements of pressure swing adsorption-gas separation operations to be significantly reduced.