Methods are provided for reducing the quantity of acid gas reinjected into a reservoir by partial CO.sub.2 removal processes. The methods include acid gas removal, acid gas enrichment, generation of a CO.sub.2 rich stream and an H.sub.2S rich stream, and reinjection of the H.sub.2S rich stream into the reservoir. The acid gas enrichment can be performed by a solvent-based acid gas enrichment unit, a membrane-based acid gas enrichment unit, or a combination of a solvent-based acid gas enrichment unit a and membrane-based acid gas enrichment unit. The system includes an acid gas removal unit, one or more acid gas enrichment units, and an acid gas reinjection compressor. The acid gas enrichment unit can be a solvent-based acid gas enrichment unit, a membrane-based acid gas enrichment unit, or a solvent-based acid gas enrichment unit and a membrane-based acid gas enrichment unit.

Methods are provided for reducing the quantity of acid gas reinjected into a reservoir by partial CO.sub.2 removal processes. The methods include acid gas removal, acid gas enrichment, generation of a CO.sub.2 rich stream and an H.sub.2S rich stream, and reinjection of the H.sub.2S rich stream into the reservoir. The acid gas enrichment can be performed by a solvent-based acid gas enrichment unit, a membrane-based acid gas enrichment unit, or a combination of a solvent-based acid gas enrichment unit a and membrane-based acid gas enrichment unit. The system includes an acid gas removal unit, one or more acid gas enrichment units, and an acid gas reinjection compressor. The acid gas enrichment unit can be a solvent-based acid gas enrichment unit, a membrane-based acid gas enrichment unit, or a solvent-based acid gas enrichment unit and a membrane-based acid gas enrichment unit.

Disclosed is the preparation of composite fluid separation membranes based on poly (aryl ether ketone) (PAEK) polymers with the separation layer formed by a layer-by-layer reticular synthesis. The porous PAEK substrate is semicrystalline, exhibits a mesoporous surface structure, and is surface functionalized. The separation layer formed by the hierarchical layer-by-layer process is in the form of a covalent organic network integrally linked via covalent bonds to the functional groups of the substrate. The composite separation layer may be synthesized in situ in a preformed separation device on the surface of the PAEK substrate. Device configurations include flat sheet, spiral wound, monolith, and hollow fiber configurations with the hollow fiber configuration being preferred. Hollow fibers are formed from PAEK polymers with poly (ether ether ketone) and poly (ether ketone) particularly preferred. Composite PAEK membranes of the present invention are useful for a broad range of fluid separation applications.

Disclosed is the preparation of composite fluid separation membranes based on poly (aryl ether ketone) (PAEK) polymers with the separation layer formed by a layer-by-layer reticular synthesis. The porous PAEK substrate is semicrystalline, exhibits a mesoporous surface structure, and is surface functionalized. The separation layer formed by the hierarchical layer-by-layer process is in the form of a covalent organic network integrally linked via covalent bonds to the functional groups of the substrate. The composite separation layer may be synthesized in situ in a preformed separation device on the surface of the PAEK substrate. Device configurations include flat sheet, spiral wound, monolith, and hollow fiber configurations with the hollow fiber configuration being preferred. Hollow fibers are formed from PAEK polymers with poly (ether ether ketone) and poly (ether ketone) particularly preferred. Composite PAEK membranes of the present invention are useful for a broad range of fluid separation applications.

A polymer blend membrane includes a polyether-based copolymer and a polyether polymerized in situ and has high permeability and high selectivity for carbon dioxide. In the polymer blend membrane, the free volume of the polyether-based copolymer is greatly increased, and the adsorption capacity for carbon dioxide is enhanced. Thus, it can have excellent mechanical properties and excellent permeability and selectivity for carbon dioxide.

Mesoporous poly (aryl ether ketone) articles are formed from blends of poly (aryl ether ketones) with pore forming additives by melt processing, and can be in the form of a monofilament, disc, film, microcapillary or other complex shapes. The method of formation provides for preparation of poly (aryl ether ketone) articles with high degree of surface area and uniform nanometer pore size. The preferred poly (aryl ether ketone)s are poly (ether ketone) and poly (ether ether ketone). The mesoporous articles formed by the method of the present invention are useful for a broad range of applications, including molecular separations and organic solvent filtration.

The present invention relates to a separation membrane including a thermoplastic polymer selected from a cellulose ester and a polyamide, in which, when regions obtained by dividing a cross-sectional surface perpendicular to a longitudinal direction of the separation membrane into 5 at an equal interval are defined as regions 1 to 5, all the regions 1 to 5 have a number average pore diameter changing rate a of −0.25 to 0.25, and at least one of the regions 1 to 5 is a region P that satisfies conditions (a) and (b): (a) a value of area average pore diameter D.sub.s/number average pore diameter D.sub.n is 2.50 to 6.00; and (b) a number average W of fine pores that are located at a distance smaller than L.sub.a from a center of respective coarse pores is 10 to 30.

The present invention relates to a separation membrane including a thermoplastic polymer selected from a cellulose ester and a polyamide, in which, when regions obtained by dividing a cross-sectional surface perpendicular to a longitudinal direction of the separation membrane into 5 at an equal interval are defined as regions 1 to 5, all the regions 1 to 5 have a number average pore diameter changing rate a of −0.25 to 0.25, and at least one of the regions 1 to 5 is a region P that satisfies conditions (a) and (b): (a) a value of area average pore diameter D.sub.s/number average pore diameter D.sub.n is 2.50 to 6.00; and (b) a number average W of fine pores that are located at a distance smaller than L.sub.a from a center of respective coarse pores is 10 to 30.

Disclosed is the preparation of composite membranes formed by a tailored selective chemical modification of an ultra-thin nanoporous surface layer of a semi-crystalline mesoporous poly (aryl ether ketone) membrane with graded density pore structure. The composite separation layer is synthesized in situ on the poly (aryl ether ketone) substrate surface and is covalently linked to the surface of the semi-crystalline mesoporous poly (aryl ether ketone) membrane. Hollow fiber configuration is the preferred embodiment of forming the functionalized the poly (aryl ether ketone) membranes. Composite poly (aryl ether ketone) membranes of the present invention are particularly useful for a broad range of fluid separation applications, including organic solvent ultrafiltration and nanofiltration to separate and recover active pharmaceutical ingredients.

A polysulfone-urethane copolymer is disclosed, which can be used as a membrane polymer, e.g., a matrix polymer, a pore forming agent, or both, while enhancing a membrane's blood compatibility. Methods are disclosed for forming the copolymer and incorporating the copolymer in membranes (e.g., spun hollow fibers, flat membranes) and other products.