The present disclosure provides a hydrophilic, integrally asymmetric, semi-permeable hollow-fiber membrane made from a hydrophobic aromatic sulfone polymer and at least one hydrophilic polymer, the membrane comprising an inner surface facing towards its lumen, an outer surface facing outwards and an intermediate wall having a wall thickness and comprising an open-pore separating layer and an supporting layer having an asymmetric, sponge-like structure without finger pores, wherein adjoining to the wall of the inner surface the hollow-fiber membrane comprises an essentially isotropic zone; after which the pore size abruptly start increasing up to a maximum, after which the pore size decrease again, then adjoining an essentially isotropic supporting layer which then is adjoined by the outer surface, wherein the separating layer has a cut-off of greater than 300 000 Daltons. The present disclosure further provides a method for producing such membranes and a use of the membranes for microfiltration purposes.

Hydrophobic poly(4-methyl-1-pentene) hollow fiber membrane for retention of anesthetic agents with an inner and an outer surface and between inner and outer surface an essentially isotropic support layer with a sponge-like, open-pored, microporous structure free of macrovoids and adjacent to this support layer on the outer surface a dense separation layer with a thickness between 1.0 and 3.5 μm. The membrane has a porosity in the range of greater than 35% to less than 50% by volume and a permeance for CO.sub.2 of 20-60 mol/(h.Math.m.sup.2.Math.bar), a gas separation factor α(CO.sub.2/N.sub.2) of at least 5 and a selectivity CO.sub.2/anesthetic agents of at least 150.

The process for producing this membrane is based on a thermally induced phase separation process in which process a homogeneous solution of a poly(4-methyl-1-pentene) in a solvent system containing components A and B is formed, wherein component A is a strong solvent and component B a weak non-solvent for the polymer component. After formation of a hollow fiber the hollow fiber is cooled in a liquid cooling medium to form a hollow fiber membrane. The concentration of the polymer component in the solution may be in the range from 42.5 to 45.8 wt.-% and the hollow fiber leaving the die runs through a gap between die and cooling medium with a gap length in the range of 5-30 mm.

The present invention relates to a hydrophilic polyimide including at least one type of building blocks [A-B] and [A-C], and represented by the formula -[A-B].sub.n-[A-C].sub.m— (I), wherein: the n-bracketed building blocks and the m-bracketed building blocks are randomly distributed over the polyimide chain; repeat unit A results from a monomer comprising two carboxylic anhydride moieties, repeat unit B is hydrophilic and results from a first hydrophilic monomer comprising two primary amine moieties and at least one further hydrophilic moiety different from the primary amines, and repeat unit C is hydrophilic and results from a second hydrophilic monomer comprising two primary amine moieties and at least one further hydrophilic moiety different from the primary amines; wherein: n and m represent independently an integer from 0 to about 1000; wherein n+m is an integer from about 10 to about 1000.

The present invention also relates to a porous membrane comprising the same, a method of producing the hydrophilic polyimide and the porous membrane, a liquid phase separation system comprising the porous membrane, and a liquid phase separation method.

The purpose of the invention is to provide a porous hollow-fiber membrane containing a regenerated cellulose and having an elastic limit pressure of 200 kPa or more.

A hollow fiber membrane of the present invention is a hollow fiber membrane having an outer surface and an inner surface, wherein the inner surface has a zebra stripe pattern in which dense portions and porous portions are alternately formed in the longitudinal direction, and the outer surface has a maximum pore size of about 1 m or less (about 1 m), and wherein the hollow fiber membrane has a water permeability (flux) of about 1,300 LMH/bar to about 5,000 LMH/bar.

The present invention relates to a hollow fiber membrane. Provided is a cylindrical hollow fiber membrane having an inside in which a hollow part is formed along an axial direction, the hollow fiber membrane including: a first layer positioned at the outermost part so as to be exposed to the outside, and having pores formed therein to make raw water enter and leave via the pores; a second layer formed on the inside of the first layer to filter out contaminants from raw water as the raw water passes through; and a third layer to optionally separate or filter out contaminants from the raw water introduced through the second layer or introduced from the hollow part, wherein the first layer to the third layer are integrally formed; the porosity of the first layer is greater than the porosity of the third layer; and porosities are gradually decreased from the first layer to the third layer.

A system for degassing a hydrocarbon fluid from a hydrocarbon liquid has a plurality of hollow tube membranes. The hollow tube membranes are formed of a plastic providing an inner support body and an outer selective layer which is denser than the inner support body. The inner support body is formed of spherulitic structures. A fuel supply system and a method are also disclosed.

A Polyvinylidene fluoride-based microporous membrane comprising: a substrate film; and the following microporous membrane, wherein the microporous membrane is an asymmetric membrane, and has a skin layer in which micropores are formed and a support layer which supports the skin layer and in which pores larger than the micropores are formed, a material of the microporous membrane is a polyvinylidene fluoride-based resin, the skin layer has a plurality of spherical bodies, a plurality of linear binding materials extend three-dimensionally from the respective spherical bodies, the adjacent spherical bodies are connected with each other by the linear binding materials to form a three-dimensional network structure where the spherical bodies serve as intersections, and the number of defects (the number of colored coarse voids) is less than 20.

The present invention relates to a combined C3/C4 splitter with a membrane system. More specifically, the present invention relates to a combined C3/C4 splitter column to separate highly pure propylene product from a liquefied petroleum gas stream, which eliminates a C3 splitter having over 120 trays and the additional equipment that a C3 splitter requires.

An method of making a porous asymmetric membrane involves dissolving a poly(phenylene ether), poly(phenylene ether) copolymer, polyethersulfone, polysulfone, polyphenylsulfone, polyimide, polyetherimide, polyvinylidene fluoride, or a combination thereof in a water-miscible polar aprotic solvent to provide a membrane-forming composition; and phase-inverting the membrane-forming composition in a first non-solvent composition composed of water, a water-miscible polar aprotic solvent, or a mixture thereof, and a polymer additive dissolved in the first non-solvent composition. The method can be a method of making a hollow fiber by coextrusion through a spinneret having an annulus and a bore, including coextruding the membrane-forming composition through the annulus, and the first non-solvent composition through the bore, into a second non-solvent composition composed of water, a water-miscible polar aprotic solvent, or a mixture thereof to form the hollow fiber.