Dual-layer hollow fibre membrane

A method for manufacturing a dual-layer hollow fibre membrane, the method comprising:

• co-extruding a bore fluid, a macromolecular polymer mixed with a first solvent, wherein the macromolecular polymer is a polysulfone and a combination of polymers mixed with a second solvent, wherein the combination of polymers is selected from at least one of an imide-based polymer and at least one of an imidazole-based polymer,
• and thereby obtaining a dual-layer hollow fibre membrane;
• immersing the dual-layer hollow fibre membrane in a first solution in a first vessel;
• and
• immersing the dual-layer hollow fibre membrane in a second solution in a second vessel;
• wherein the imide-based polymer of the dual-layer hollow fiber membrane is a polyamide-imide, PAI, and the imide-based polymer comprises 5 to 50% by weight of PAI with respect to an outer layer of the dual-layer hollow fiber membrane.

A method for separating gases from a feed gas stream, the method comprising:

• feeding a feed gas stream in a membrane module comprising at least one dual-layer hollow fibre membrane, wherein
• the dual-layer hollow fibre membrane comprises the inner layer of a macromolecular polymer, wherein the macromolecular polymer is a polysulfone, and an outer layer made of a combination of polymers and wherein the combination of polymers is selected from at least one of an imide-based polymer and at least one of an imidazole-based polymer;
• wherein
• the imide-based polymer is a polyamide-imide, PAI, and the imide-based polymer comprises 5 to 50% by weight of PAI with respect to the outer layer;
• increasing the pressure along the membrane module;
• and
• outputting a purer gas mixture.

A method for measuring the separation performance of a dual-layer hollow fibre membrane, the method comprising:

• feeding a feed gas stream in a membrane module comprising at least one dual-layer hollow fibre membrane, wherein
• the dual-layer hollow fibre membrane comprises an inner layer of a macromolecular polymer, wherein the macromolecular polymer is a polysulfone, and an outer layer made of a combination of polymers and wherein the combination of polymers is selected from at least one of an imide-based polymer and at least one of an imidazole-based polymer;
• wherein
• the imide-based polymer is a polyamide-imide, PAI, and the imide-based polymer comprises 5 to 50% by weight of PAI with respect to the outer layer;
• increasing the pressure along the membrane module;
• outputting a purer gas mixture;
• and
• measuring the separation performance of the dual-layer hollow fibre membrane by evaluating the pressure difference between the feed gas stream and the permeate gas stream and by measuring the flow rate and the gas composition of the feed gas stream and the permeate gas stream.