Abstract: A process for the separation or concentration of olefinic hydrocarbons from mixtures of olefinic and paraffinic hydrocarbons uses a polyimide membrane, The process is well suited to separating propylene from propylene/propane mixtures. The novel method The membrane exhibits good resistance to plasticization by hydrocarbon components in the gas mixture under practical industrial process conditions.

Abstract: This abstract discusses membranes needed to separate fluids for the production of oxygen-enriched air, nitrogen-enriched-air, for the separation of carbon dioxide from hydrocarbons, and the separation of hydrogen from various petrochemical and oil refining streams. Membranes are needed that provide a resistance to interaction with process components or contaminants, provide the mechanical strength required to withstand high membrane differential pressures and high process temperatures, and exhibit sufficient maximum strain such that membranes are not brittle and can easily be formed into desirable membrane forms. Membranes of polyimide polymers, particularly polyimide polymers sold under the trade name P-84, are annealed in a controlled annealing step to improve the mechanical properties of the polymers used to make separation membranes.

Abstract: Membranes are used to separate fluids for the production of oxygen-enriched air, nitrogen-enriched-air, for the separation of carbon dioxide from hydrocarbons, and the separation of hydrogen from various petrochemical and oil refining streams. Membranes are discussed that provide a resistance to interaction with process components or contaminants, which can lead to plasticizing of the membrane, while providing the mechanical strength required to withstand high membrane differential pressures and high process temperatures. Membranes of blended polymers are used to improve the mechanical strength of the polymers used to make separation membranes. Specifically, polyimide polymers are combined with a blend polymer that is a polyamide and/or a polyamide-imde polymer. The resulting polymer mix is used to produce various forms of high strength, chemically resistant membranes, including hollow-fiber membranes that are suitable for high pressure, high temperature applications.

Abstract: This abstract discusses producing mixed matrix composite (MMC) membranes with a good balance of permeability and selectivity. MMC membranes are particularly needed for separating fluids in oxygen/nitrogen separation processes, processes for removing carbon dioxide from hydrocarbons or nitrogen, and the separation of hydrogen from petrochemical and oil refining streams. MMC Membranes made using washed sieve material, such as washed SSZ-13 sieve material, provide surprisingly good permeability and selectivity. The method of the current invention produces a fluid separation membrane by providing a polymer and a washed molecular sieve material, then synthesizing a concentrated suspension of a solvent, the polymer, and the washed molecular sieve material. The concentrated suspension is used to form the fluid separation membrane of the desired configuration. Membranes of the current invention can be formed into hollow fiber membranes that are particularly suitable for high trans-membrane pressure applications.