WO2024123245A1

WO2024123245A1 - Membrane cartridge and gas separation arrangement for separating gas

Info

Publication number: WO2024123245A1
Application number: PCT/SG2023/050807
Authority: WO
Inventors: Mohammad Askari; Ali Naderi
Original assignee: Divigas Pte Ltd
Priority date: 2022-12-05
Filing date: 2023-12-05
Publication date: 2024-06-13
Also published as: WO2024121590A1

Abstract

A membrane cartridge (120) for separating gas, comprising: a first end part (122); a second end part (124); a distance part (126) connecting the first end part (122) and the second end part (124); a plurality of hollow fiber membranes (128) extending from the first end part (122) to the second end part (124); and a space (4) arranged at a lateral side (28) of the plurality of hollow fiber membranes (128) and between the first end part (122) and the second end part (124); wherein the second end part (124) comprises a recess (134) arranged at a lateral side (24) of the second end part (124) and at least one hole (132); wherein the recess (134) is in fluid connection with the space (4), via the at least one hole (132).

Description

MEMBRANE CARTRIDGE AND GAS SEPARATION ARRANGEMENT FOR SEPARATING GAS

Technical field

This disclosure relates to separation of fluids, especially it relates to arrangements for separating a specific gas from a gas mixture.

Background

Hydrogen is a clean and high-quality energy carrier, it plays a crucial role for us to achieve a sustainable and clean energy world. The major route for the production of hydrogen is through the steam reforming of hydrocarbons followed by water-gas shift reaction. Some publications related to hydrogen production are [1-3],

For example, Hydrogen is a power source for vehicles, like trains, buses, and cars. Unelectrified railways can then be trafficked by environmentally friendly hydrogen drive trains instead of Diesel driven trains. Thus, hydrogen is a good alternative as power source for vehicles, where it will contribute to replace fossil fuels like Diesel and gasoline. Hydrogen may also be used for energy storage, and for heating buildings and replace coal and oil, etc.

The need for clean hydrogen increases; therefore, it is a challenge to improve its production and make it more effective.

Summary

It would be desirable to improve performance in gas production. It is an object of this disclosure to address at least one of the issues outlined above.

Further there is an object to devise an arrangement and a method that facilitates increased purity of desired gases. These objects may be met by an arrangement according to the attached independent claims.

According to a first aspect there is provided a membrane cartridge for separating gas, comprising: a first end part, arranged at a first end of the membrane cartridge; a second end part, arranged at a second end of the membrane cartridge; a distance part connecting the first end part and the second end part with a fixed distance therebetween; a plurality of hollow fiber membranes extending from the first end part to the second end part, wherein each one of the hollow fiber membranes is connected with a first end to the first end part and a second end to the second end part; and a space arranged at a lateral side of the plurality of hollow fiber membranes and between the first end part and the second end part; wherein the second end part comprises a recess arranged at a lateral side of the second end part and at least one hole extending from the space through the second end part, to the recess; wherein the recess is in fluid connection with the space via the at least one hole; and wherein the first end of the membrane cartridge is in fluid connection with the second end of the membrane cartridge via the hollow fiber membranes.

To illustrate the advantages of the membrane cartridge, an exemplary gas separation arrangement comprising the membrane cartridge will be described below. The membrane cartridge may be used in such an exemplary gas separation arrangement or in another gas separation arrangement.

An exemplary gas separation arrangement for separating gas, may comprise: a housing comprising: a first gas port and a cartridge port; and a membrane cartridge according to the first aspect, wherein the housing is configured to receive the membrane cartridge by the cartridge port; wherein the first end part of the membrane cartridge, the second end part of the membrane cartridge, and a lateral side wall of the housing are configured to form a chamber when the membrane cartridge is received by the cartridge port, the space at the lateral side of the plurality of hollow fiber membranes of the membrane cartridge being at least part of the chamber; wherein the first gas port is arranged to connect to the recess at the lateral side of the second end part of the membrane cartridge, when the membrane cartridge is received by the cartridge port, such that the first gas port comes into fluid connection with the chamber via the recess and the at least one hole.

Fig. 1C illustrates a membrane cartridge 120 and Fig. ID illustrates a housing 110. Together, the membrane cartridge 120 of Fig. 1C and the housing 110 of Fig. ID may form a gas separation arrangement 100. The membrane cartridge 120 may be configured to slide into the cartridge port 118 of the housing 110, whereby the membrane cartridge 120 is received by the housing 110. Fig. 1A and IB illustrate gas separation arrangements based on the membrane cartridge of Fig. 1C and the housing of Fig. ID. Figs 1A-D are cross-sectional views. Figs 1A-D may be seen as schematic illustrations. The membrane cartridge 120 and gas separation arrangement 100 are described in more detail in Figs 2-4 and the associated text.

In the following, the membrane cartridge 120 will be described. Primarily exemplified by Figs 1A-

D. The hollow fiber membranes 128 may comprise a polymer, preferably a glassy or rubbery polymer from a group of: polyethersulfone, polysulfone, polyimide, Silicon rubber, Polyphenylene oxide, Cellulose acetate, Polyaramide. The hollow fiber membranes may have outer diameters in a range of 100 pm to 3000 pm. Such materials and/or outer diameters may facilitate effective gas separation. In particular, effective gas separation of hydrogen gas. In the following, the term hollow fiber membrane may be used interchangeably with the term hollow fiber.

The first end part 122 may be made of polymer and/or metal. The first end part 122 may be molded or cast around a first end of the hollow fiber membranes 128. Thereby, each one of the hollow fiber membranes 128 may be connected with its first end to the first end part 122.

The second end part 124 may be made of polymer and/or metal. The second end part 124 may be molded or cast around a second end of the hollow fiber membranes 128. Thereby, each one of the hollow fiber membranes 128 may be connected with its second end to the second end part 124.

The first end 1 of the membrane cartridge 120 is in fluid connection with the second end 2 of the membrane cartridge 120 via the hollow fiber membranes 128. The openings of the hollow fiber membranes 128 may be arranged at the respective first end 1 and second end 2 of the membrane cartridge 120. Thus, gas may flow from the first end 1 to the second end 2 of the membrane cartridge 120 via the hollow fiber membranes 128.

The distance part 126 may e.g. be a rod or a bar. The distance part 126 may be rigid. Thus, the distance part 126 may be configured to rigidly connect the first end part 122 with the second end part 124. The distance part 126 may keep the first end part 122 and the second end part 124 at a fixed distance, even though the hollow fiber membranes 128 may be non-rigid. The distance part 126 may e.g. be made of metal. The membrane cartridge 120 may comprise a plurality of distance parts 126, e.g. a plurality of rods.

As illustrated in Fig. 1C, the membrane cartridge 120 comprises a space 4 arranged at a lateral side 28 of the plurality of hollow fiber membranes 128 and between the first end part 122 and the second end part 124. In the cross-sectional view of Fig. 1C, the space 4 may be seen as extending vertically from the first end part 122 to the second end part 124. In the cross-sectional view of Fig. 1C, the space 4 may be seen as extending laterally from the lateral side 28 of the plurality of hollow fiber membranes 128, equally far as the first end part 122 and/or the second end part 124 extends laterally from the lateral side 28 of the plurality of hollow fiber membranes 128.

As illustrated in Fig. 1C, a recess 134 is arranged at a lateral side 24 of the second end part 124. Further, at least one hole 132 extends from the space 4, through the second end part 124, to the recess 134. The membrane cartridge may be configured such that the at least one hole comprises at least six holes. In the following, the housing 110 will be described as well as how the membrane cartridge 120 and housing 110 may form a gas separation arrangement 100. This is primarily exemplified by Figs 1A-D.

The housing 110 may be a hollow container. The housing 110 may be a hollow cylinder. The cartridge port 118 may be an opening at one end of the housing 110.

Fig. 1C-D illustrates that the membrane cartridge 120 may be configured to slide through the cartridge port 118 such that the membrane cartridge 120 is received by the cartridge port 118. The first end part 122 of the membrane cartridge 120, the second end part 124 of the membrane cartridge 120, and a lateral side wall 10 of the housing 110 form a chamber 102 when the membrane cartridge 120 is received by the cartridge port 118. Thus, lateral side walls 10 of the housing 110 may form lateral side walls of the chamber 102 while the first 122 and second 124 end part of the membrane cartridge 120 may form end walls of the chamber 102. Thus, when the membrane cartridge 120 is received by the cartridge port 118, the hollow fiber membranes 128 may be inside the chamber 102 and the space 4 at the lateral side 28 of the hollow fiber membranes 128 may form a part of the chamber 102.

The cartridge port 118 may have the same shape as the first 122 and second 124 end part of the membrane cartridge 120. The first 122 and second 124 end part of the membrane cartridge 120 may be cylindrical. The cartridge port 118 may be cylindrical.

The housing 110 comprises a first gas port 112, as illustrated in Fig. ID. The first gas port 112 is arranged to connect to the recess 134 at the lateral side 24 of the second end part 124 of the membrane cartridge 120, when the membrane cartridge 120 is received by the cartridge port 118, as illustrated in Figs 1A-B. Thus, when the membrane cartridge 120 is received by the cartridge port 118, the first gas port 112 comes into fluid connection with the chamber 102 via the recess 134 and the at least one hole 132.

The housing 110 may comprise further gas ports, such as a second gas port 114; a third gas port 116; a fourth gas port 117, as illustrated in e.g. Fig. IB. Gas ports may alternatively be called gas connectors. The two terms may be used interchangeably in this disclosure.

Accordingly, the gas separation arrangement may be configured such that the housing comprises a second gas port arranged to be in fluid connection with an inside of the hollow fiber membranes, when the membrane cartridge is received by the cartridge port.

The gas separation arrangement may be used either in outside-in flow configuration, as illustrated in Fig. 1A, or inside-out flow configuration, as illustrated in Fig. IB. Accordingly, the membrane cartridge 120 may be used either in outside-in flow configuration or inside-out flow configuration. In the outside-in flow configuration, gas may enter through the first gas port 112 and flow into the space 4 at the lateral side 28 of the hollow fiber membranes 128 (the space 4 being part of the chamber 102) via the recess 134 and the at least one hole 132, as illustrated in Fig. 1A. Thus, the gas arrives at the outside of the hollow fiber membranes 128. Part of the gas, e.g. smaller molecules of the gas such as hydrogen, may then move through the hollow fiber membranes 128, to the inside of the hollow fiber membranes 128, and be collected at the first 1 or second 2 end of the membrane cartridge, e.g. at a second gas port 114 of the housing 110 in fluid connection with the first 1 or second 2 end of the membrane cartridge 120.

In the inside-out flow configuration, gas may enter at the inside of the hollow fiber membranes 128, e.g. at the first end 1 or second end 2 of the membrane cartridge 120. This is illustrated in Fig. IB wherein gas enters at the second gas port 114. Part of the gas, e.g. smaller molecules of the gas such as hydrogen, may then move through the hollow fiber membranes 128, to the outside of the hollow fiber membranes 128 and into the space 4 at the lateral side 28 of the hollow fiber membranes 128 (the space 4 being part of the chamber 102). The part of the gas may then exit through the at least one hole 132, the recess 134 and the first gas port 112 or through another gas port. In Fig. IB the part of the gas exits through the third gas port 116 since a sealing lid 308 seals the first gas port 112. However, the sealing lid 308 may be removed such that the part of the gas may exit through the first gas port 112 alone or through both the first gas port 112 and the third gas port 116.

The first 122 and second 124 end part of the membrane cartridge 120 may be configured to seal against the housing 100. For example, the first 122 and second 124 end part may comprise one or more o-ringS. The second end part 124 may comprise an o-ring on each side of the recess 134. Similarly, the first end part 122 may comprise an o-ring. The first 122 and second 124 end part of the membrane cartridge 120 may be configured to seal against the lateral wall 10 of the housing 110. Alternatively, the first 122 and second 124 end part of the membrane cartridge 120 may be configured to seal against another part of the housing 110, as shown in Fig. 1A-B.

An advantage of the membrane cartridge 120 is that it facilitates easy gas flow. As mentioned, the space 4 is arranged at the lateral side 28 of the hollow fiber membranes and between the first end part and the second end part 124. Thus, gas may easily flow along the lateral side 28 of the hollow fiber membranes 128. Thus, the entire length of the hollow fiber membranes 128 may be effectively utilized. A space 4 along the lateral side 28 of the hollow fiber membranes 128 may be particularly useful in the outside-in flow configuration in order to avoid congestion along the length of the hollow fiber membranes 128 which may lead to differences in pressure or hydrogen concentration along the length of the hollow fiber membranes 128. An advantage of the membrane cartridge 120 is that it facilitates easy reconfiguration of the gas separation arrangement 110. Since the recess 134 is in fluid connection with the space 4, via the at least one hole 132, the membrane cartridge 120 may be seen as contributing to the flow control. In the exemplary gas arrangement, the first gas port 112 comes into fluid connection with the chamber 102 via the recess 134 and the at least one hole 132 so that that the membrane cartridge 120 can contribute to the flow control. Thus, the gas flow and/or pressure and/or flow distribution may be modified by changing the membrane cartridge 120. For example, changing to a membrane cartridge 120 with more holes 132, or fewer holes 132, or differently sized holes 132, may change the gas flow and/or pressure and/or flow distribution in the chamber 102. This may facilitate a user friendly gas separation arrangement 110 which may be reconfigured by a user having limited experience, by simply changing the membrane cartridge 120.

A further advantage may be that, in the outside-in flow configuration, the gas may enter the chamber along the hollow fiber membranes 128 instead of perpendicular to them. Thus, pressure differences along the length of the hollow fiber membranes 128 may be avoided.

The membrane cartridge 120 may be configured such that an axis of the at least one hole deviates from a direction perpendicular to the hollow fiber membranes . When the gas is injected into the chamber in a direction that is not perpendicular to the hollow fiber membranes the surface of the hollow fiber membranes may be more efficiently used. Further, the pressure at the hollow fiber membrane surface may be even along the length of the hollow fiber membrane. Consider the following: if gas is injected perpendicular to the hollow fiber membranes at one end of the hollow fiber membranes, the dynamic gas pressure may be higher at this end than at the opposite end. The axis of the at least one hole may have a direction parallel to the hollow fiber membranes. The axis of the at least one hole may have a direction within 30 degrees from the direction of the hollow fiber membranes.

The membrane cartridge may be configured such that the second end part comprises a rim, wherein the rim extends around the hollow fiber membranes and overhangs the space such that the space extends around the hollow fiber membranes, wherein the at least one hole is arranged in the rim.

A membrane cartridge wherein the second end part comprises a rim 12 may be seen in Fig. 1C. As illustrated in Fig. 1C, the rim 12 may be arranged between the recess 134 and the space 4. Thus, the rim 12 may separate the recess 134 from the space 4. The rim 12 may be configured to engage the housing 110 such that the gas is guided into the chamber 102 via the hole 132. Since the rim 12 extends around the hollow fiber membranes 128, the space 4 also extends around the hollow fiber membranes 128. Thus, unrestricted gas flow around the hollow fiber membranes 128 may be ensured. In the perspective view of Fig. 2A, a rim 12 that extends around the hollow fiber membranes 128 is seen.

An outer diameter of the rim 12 may be at least 10% larger than an inner diameter of the rim 12. When the outer diameter of the rim 12 is at least 10% larger than the inner diameter of the rim 12, a sufficient space around the hollow fiber membranes may be ensured. It may be advantageous to use even larger outer diameters. For example, the outer diameter of the rim 12 may be at least 20%, or at least at least 40%, larger than the inner diameter of the rim 12. In Fig. 2C, being a cross-sectional view of the membrane cartridge 120, a rim 12 is seen. The inner diameter of the rim 12 may be defined by the region (e.g. central region) of the second end part 124 through which the hollow fiber membranes 128 extend. Thus, Fig. 2C shows a rim 12 having an outer diameter being at least 10% larger than an inner diameter.

The gas separation arrangement may be configured such that, when the membrane cartridge is received by the cartridge port: a cross section of the chamber comprises an inner area through which the hollow fiber membranes extend, the inner area being less than 85% of a full area of the cross section of the chamber, the cross section being perpendicular to the hollow fiber membranes.

This may ensure sufficient space around the hollow fiber membranes, in analogy to the discussion above. For example, if a cross section of the chamber is circular with a diameter being 10 % larger than the diameter of a circular inner area through which the hollow fiber membranes extend, then the inner area may be less than 85% of the full area of the cross section of the chamber.

In the case the rim seals against the lateral side wall of the housing, the diameter of the cross section of the chamber may be the same or slightly larger than the outer diameter of the rim.

The membrane cartridge may be configured such that the recess is a circumferential recess about a periphery of the second end part. A circumferential recess 134 is e.g. seen in Fig. 2A. A circumferential recess may ensure that the gas flow is evenly distributed around the hollow fiber membranes. Further, a whirl of gas may be created when the gas flows around the circumferential recess, e.g. if the gas is guided by the circumferential recess before entering the holes. Creating a whirl of gas may be advantageous as it may facilitate an even gas distribution in the chamber.

The membrane cartridge may be configured such that the plurality of hollow fiber membranes comprises at least a first and a second bundle of hollow fiber membranes; and a passage extending from the space at the lateral side of the plurality of hollow fiber membranes and in-between the first and second bundle of hollow fiber membranes.

The passage may facilitate easy flow of gas to hollow fiber membranes at the center of the membrane cartridge, e.g. at, or close to, the center axis of the membrane cartridge. This may reduce a pressure difference between hollow fiber membranes next to the space at the lateral side of the plurality of hollow fiber membranes and hollow fiber membranes at the center of the membrane cartridge. The passage may be a slit, a vent, or a channel between the first and second bundle of hollow fiber membranes.

The membrane cartridge may further comprise a dividing wall arranged between the first and second bundle of hollow fiber membranes, the dividing wall having a corrugated surface comprising at least one groove, the at least one groove extending from the space at the lateral side of the plurality of hollow fiber membranes and in-between the first and second bundle of hollow fiber membranes such that the at least one groove forms the passage.

The groove may be directed from the space at the lateral side of the plurality of hollow fiber membranes towards the center axis of the membrane cartridge. The groove may be directed perpendicular to the center axis of the membrane cartridge.

The concept of dividing walls 130 between bundles of hollow fiber membranes 128 is shown in Fig. 2A and 2C. Fig. 2A illustrates a side view of a membrane cartridge 120 in a housing 110. For illustrative purposes, parts of the housing 110 has been removed. Similarly, for illustrative purposes the hollow fiber membranes 128 have been removed. Fig. 2C illustrate a cross sectional view of the same membrane cartridge 120 in the housing 110, herein the hollow fiber membranes 128 are visible. Fig. 2C shows four dividing walls 130 extending outwards from the center axis of the membrane cartridge 120, thereby dividing the hollow fiber membranes 128 into four bundles (one in each quadrant). There may of course be more or fewer dividing walls 130. In Fig. 2A, the dividing wall 130 has a corrugated surface comprising a plurality of grooves 30 that forms the passages 14. In the illustration, the grooves 30 are directed perpendicular to the center axis of the membrane cartridge 120. The center axis of the membrane cartridge 120 may be parallel with the hollow fiber membranes 128.

The gas separation arrangement may be configured such that the housing comprises a recess configured to align with the recess at the lateral side of the second end part of the membrane cartridge, when the membrane cartridge is received by the cartridge port, the recess of the housing being in fluid connection with the first gas port such that the first gas port comes into fluid connection with the recess at the lateral side of the second end part of the membrane cartridge via the recess of the housing.

Fig. ID as well as Figs 1A-B illustrate that the housing may comprise a recess 34 configured to align with the recess 134 at the lateral side 24 of the second end part 124 of the membrane cartridge 120. Such a recess 34 of the housing may be used as a dispersion atrium. Brief description of drawings

The solution will now be described in more detail by means of exemplifying embodiments and with reference to the accompanying drawings, in which:

Figures 1A-B are schematic illustrations of arrangements for separating gases, according to possible embodiments.

Figure 1C is a schematic illustration of a membrane cartridge.

Figure ID is a schematic illustration of a housing.

Figure 2A is a schematic illustration of a membrane cartridge, according to possible embodiments.

Figure 2B is a schematic illustration of a housing, according to possible embodiments.

Figure 2C is a schematic illustration of a cross-section, according to possible embodiments.

Figures 3A-D are schematic illustrations of details of a lids, according to possible embodiments.

Figure 4 is a schematic illustration of arrangement for separating gases, according to possible embodiments.

Figure 5 is a schematic illustration of a method of separating gases, according to possible embodiments.

Detailed description

In order to purify produced hydrogen, separation of H₂ from CO₂ is desired [3-5], In this regard, using membranes for H₂/CO₂ separation has attracted attention.

In this disclosure, "hollow fibers" filter gases through the walls of the hollow fibers. Each hollow fiber has an elongated lumen extending between two openings in its respective ends. The hollow fibers are used as membranes and selectively allow some gas molecules at a feed gas flow to pass through and others not, splitting the feed gas flow into a "permeate" gas flow and a "retentate" gas flow. Typically, smaller gas molecules will pass through pores of the hollow fibers' walls, but larger gas molecules will be prevented from passing.

In the exemplifying embodiments below, the fiber walls are configured to filter out Hydrogen molecules H₂ from a feed gas flow of a mixture of various gases. However, the inventive concept is not limited to arrangements and methods for Hydrogen separation only. By adapting the fiber walls' materials and pore sizes, the described concept could be adapted for separation of any suitable gases when appropriate.

With reference to the Figures 1A and IB, which are schematic illustrations, a gas separation arrangement will now be described in accordance with some exemplifying embodiments.

Figure 1A shows an arrangement for separating gases through hollow fiber membranes, from outside into the hollow fibers' lumens, so called "shell-side membrane". The gas separation arrangement 100 comprises a housing 110 and a membrane cartridge 120. The housing 110 comprises three gas connectors 112, 114, 116, of which: a first gas connector 112 is arranged for receiving a feed gas mixture to be separated; a second gas connector 114 for delivering a permeate gas flow; and a third gas connector 116 for outputting a retentate gas flow. In this embodiment the membrane cartridge 120 have been inserted through a cartridge port 118 and together the housing 110 and the membrane cartridge 120 has established a first chamber 102 and a second chamber 104, when a sealing lid 302 is arranged over the cartridge port 118. In this embodiment, when the arrangement implements filtering into the lumens of the membranes 128, the first chamber 102 has the functionality of being input chamber, and the second chamber 104 the functionality of being outlet chamber, as will be further disclosed below.

The membrane cartridge 120 comprises a first end part 122, a second end part 124, a plurality of hollow fibers 128 with membrane walls, and a space 4 at a lateral side 28 of the plurality of hollow fiber membranes 128. In the figure, where the membrane cartridge 120 is inserted into the housing 110, this space 4 is located in the first chamber 102. The plurality of hollow fiber membranes 128 extends from the first end part 122 to the second end part 124, and each one of the hollow fiber membranes 128 is connected with a first end to the first end part 122 and with a second end to the second end part 124. The first end 1 of the membrane cartridge 120 is in fluid connection with the second end 2 of the membrane cartridge via the hollow fiber membranes.

Typically, but not illustrated in the figure 1A, the membrane cartridge 120 is provided with one or more distance parts to keep the first end part 122 and the second end part 124 at a fixed distance from each other. Thereby, when the membrane cartridge 120 is inserted in the cartridge port 118, and the sealing lid 302 is arranged, the first end part 122 separates the first chamber 102 from the second chamber 104, and the second end part 124 separates the first chamber 102 from a third chamber 106. The third chamber 106 may be referred to as a dispersion atrium for receiving feed gas. The second end part 124 has a recess 134 at its lateral side 24, i.e. about its circumference. The second end part 124 is provided with a plurality of holes 132 through which the inputted feed gas mixture is led into the first chamber 102 from the recess 134. I.e. the membrane cartridge 120 is designed such the recess 134 is in fluid connection with the space 4 via the plurality of holes 132. A circumferential recess may ensure that the gas flow is evenly distributed around the hollow fiber membranes. Further a whirl of feed gas may be created when the feed gas flows around the circumferential recess, e.g. if the feed gas is guided by the circumferential recess before entering the holes 132. Creating a whirl meh facilitate an even gas distribution in the third chamber 106.

It is to be noted that even if the figure illustrates two holes 132, the skilled designer understands how to implement the functionality of conveying the feed gas from the recess 134 into the first chamber 102 by any appropriate number of holes 132, i.e. at least one hole 132. For instance at least 10 holes 132 may be provided.

In the schematic Figure 1A, a separating wall of the housing 110 separates the first chamber 102 from the third chamber 106 by sealing against the body of the second end part 124. However, when put into practice, the second end part 124 may seal directly against the inside of the housing 110, such that the recess 134 constitutes third chamber 106. The second end part 124 may comprise a rim 12 arranged between the recess 134 and the space 4, and extending around the hollow fiber membranes 128. The rim 12 may overhang the space 4 such that the space 4 extends around the hollow fiber membranes, wherein at least one of the holes 132 is arranged in the rim. The outer diameter of the rim 12 may be at least 10% larger than its inner diameter, e.g. the diameter of the recess 134. When the diameter outer diameter of the rim 12 is at least 10% larger than the inner diameter of the rim 12, a sufficient space 4 around the hollow fiber membranes 128 may be ensured. It may be advantageous to use even larger outer diameters. For example, the outer diameter of the rim 12 may be at least 20%, or 40% larger than the inner diameter of the rim 12.

In Figure 1A, the dense arrows illustrate the feed gas flow into the gas separation arrangement 100, via the first gas connector 112 to the third chamber 106 (dispersion atrium), further through the holes 132 into the first chamber 102 to be filtered by the membranes of the hollow fibers 128. The filtering results in that the permeate gas flow passes into the hollow fibers' 128 lumens to be guided into the second chamber 104 before being outputted via the second gas connector 114 (unfilled arrow). The retentate gas flow which can't pass through the membranes, i.e. the hollow fibers' 128 walls, is instead outputted via the third gas connector 116 (medium dense arrows).

As described above, the performance of the gas separation arrangement 100 will be improved by, providing the second end part 124 with the recess 134, as the feed gas flow will be spread more even around the second and part 124 in the third chamber 106. Optionally, as will be disclosed below in conjunction with further embodiments, when the first gas connector 112 is arranged tangentially at the housing 110, the feed gas flow will describe a whirl movement in the recess 134, which facilitates the feed gas to enter the holes 132 more even. The feed gas flow will then be better dispersed in the first chamber 102, which contribute to a better use of the membrane areas, as ineffective parallel flow of the feed gas along the hollow fiber membranes 128 in the first chamber 102 will be reduced. When the feed gas is injected into the first chamber 102 in direction that is not perpendicular to the hollow fiber membranes 128, the surface of the hollow fiber membranes may be more efficiently used. Another optional design to spread the feed gas is to implement a plurality of holes 132 between the recess 134 and the first chamber 102. E.g. the through holes may be appropriately spread over the second end part 124 or the housing 110, within the disclosed concept. Moreover, the holes 132 may be designed such that their axes deviate from a direction perpendicular to the hollow fiber membranes' elongations. The axis of at least one hole 132 may have a direction within 30 degrees from the direction of the hollow fiber membranes.

Figure IB shows instead an arrangement for separating gases through hollow fiber membranes, from the hollow fibers' lumens and out to a first chamber 102, , so called "lumen-side membrane". Also in this embodiment, the gas separation arrangement 100 comprises the housing 110 and the membrane cartridge 120. The housing 110 comprises three gas connectors 112, 114, 117, but with differently intended use compared to the arrangement illustrated in Figure 1A. A second gas connector 114 is arranged for receiving a feed gas mixture to be separated; a second gas connector 116 is arranged for delivering a permeate gas flow; and a fourth gas connector 117 is arranged for outputting a retentate gas flow. In this embodiment the membrane cartridge 120 have been inserted through the cartridge port 118 and together the housing 110 and the membrane cartridge 120 has established the second chamber 104 (gas inlet) and the first chamber 102 (gas outlet), when a lid 306 with the third gas connector 117 is arranged over the cartridge port 118. A sealing lid 308 may be arranged over the former first gas connector of Figure 1A. In this embodiment, when the arrangement implements filtering into the lumens of the membranes 128, the first chamber 102 has the functionality of being input chamber, and the second chamber 104 the functionality of being outlet chamber, as will be further disclosed below.

The membrane cartridge 120 in Figure IB is identical with the one illustrated in Figure 1A and comprises also the first end part 122, the second end part 124 and a plurality of hollow fibers 128 with membrane walls. Thus, the gas separation arrangements 100 of the figures 1A and IB differ in which lids 302, 304, 306, 308 that are arranged and where they are arranged. By blocking the first gas connector 112 with the lid 308, no first chamber (dispersion atrium) will be established and that part of the housing 110 will result in a dead end, and neither the holes 132 nor the recess 134 will have any effect. By arranging the lid 306 with the fourth gas connector 117 to the left in Figure IB, the fibers' lumens 128 will instead be open in their second end 2.

In Figure IB, the dense arrows illustrate the feed gas flow, into the gas separation arrangement 100 via the second gas connector 114, into the second chamber 104, and further into the hollow fiber membranes' 128 lumens. The filtering results in that the permeate gas flow passes out from the hollow fibers membranes' 128 lumens into the first chamber 102 before being outputted via the third gas connector 116 (unfilled arrow). The retentate gas flow can't pass out through the walls of the hollow fiber membranesl28, but proceeds instead in the hollow fiber membranes' 128 lumens to the fourth gas connector 117 to be outputted (medium dense arrows).

It is to be noted that the above described embodiment is a non-limiting example of implementing the gas separation arrangement 100. When put into practice, the gas separation arrangement 100 may be configured to receive feed gas at any of its two ends and output retentate gas at its opposite end. Thus even if the feed gas is inputted at the right side and the retentate gas is outputted at the left side in Figure IB, the skilled designer is capable to implement the gas separation arrangement 100 alternatively within the disclosed concept. For instance, by arranging appropriate lids with gas connectors at the ends, the direction of the gas flow may be opposite, i.e. from the left to the right. By arranging a lid with an inlet gas connector and an appropriate recess, an inlet chamber 102 may be formed at any appropriate of the ends.

Also the right ends of the gas separation arrangement 100 may be configured as a lid with or without circular recess. As seen in the Figures 1A-B, the designer may further design any of the housing's ends as a part of the housing, i.e. as a fixed end without need for a lid in that end.

As above described and illustrated in the figures 1A-1B, the gas separation arrangement 100 may enable both shell-side membrane and lumen-side membrane perform with using one and the same equipment. Thus, due to the user's needs the gas separation arrangement 100 will satisfy the user regardless the desired type of membrane filtering. In addition the gas separation arrangement 100 facilitates a flexible service for gas separation, as the user conveniently may switch between these two types of filtering.

By easily exchanging the lids 302, 304, 306, 308, the gas separation arrangement 100 may be adapted to the appropriate type of membrane filtering, i.e. using the hollow membranes for shelltype filtering, or for lumen-type filtering.

Furthermore, as well for the shell-type and lumen-type embodiments the gas connectors for outputting retentate gas may be equipped with flow resistance arrangements in order to implement flow resistance for the retentate gases and thereby cause the desired permeate gas flow to flow through the membranes, i.e. the hollow fibers' 128 walls. In figure 1A this relates to the third gas connector 116, and in figure IB this relates to the fourth gas connector 117. The embodiments of this disclosure are directed to separate Hydrogen H₂ as permeate gas from a gas mixture, but the proposed concept is not limited to H₂ separation as such. The skilled designer understands how to adapt the membranes and select pore sizes and materials to filter out any desired appropriate gases from a gas mixture. He/she also realizes that a plurality of gas separation arrangements can be arranged together, in parallel or series, in an appropriate system, and the morphology/porosity and types of membrane may be adapted to the appropriate needs.

With reference to Figure 2A and 2B, which are schematical illustrations, a membrane cartridge 120 and a housing 110 will now be described in accordance with one exemplifying embodiment.

Figure 2A illustrates the membrane cartridge 120, Figure 2B the housing 110, and Figure 2C a cross-section through the membrane cartridge 120 when arranged in the housing 110. The markings A indicate the location of the cross-section. The membrane cartridge 120 comprises a first end part 122, a second end part 124, distance parts 126, and a plurality of hollow fibers. The hollow fibers are omitted and not shown in figure 1A in order to emphasize other parts and structures. However, the hollow fibers are seen in some other figures of this disclosure, e.g. Figs 1A, IB, and 4. The distance parts 126 are implemented as four rods that fixate the distance between the first end part 122 and the second end part 124. However, the distance parts may be alternative designed within the proposed concept. For instance, a designer may design the distance means as any suitable number of rods, or as a cylinder that encompasses the hollow fibers, when appropriate.

The second end part 124 is provided with a recess 134, from which twelve through holes 132 are distributed to led the feed gas flow into a first chamber (not referred to). The recess 134 and its functionality have been discussed above in conjunction with other embodiments. Furthermore, the number of through holes 132 and their respective directions between the recess 134 and the space 4 lateral of the hollow fiber membranes may be adapted within the inventive concept to optimize distribution of the gas flow in the first chamber. In Figure 2A is further indicated a first gas connector 112, a second gas connector 114, and a third gas connector 116. These gas connectors 112, 114, 116 are located at a housing 110, and a lid 304, respectively. However, in order to facilitate understanding they are indicated in the Figure 2A together with a piece of the housing 110 and a lid 304 with the second gas connector 114.

Furthermore, in this embodiment, the membrane cartridge 120 is provided with four dividing walls 130 to divide the hollow fibers 128 in bundles. By dividing or splitting up the hollow fibers 128 in bundles, the accessible areas of the hollow fibers 128 increase as the hollow fibers 128 are prevented to block each other. In Figure 2A, the surfaces of the membrane dividing walls 130 are corrugated with radially directed grooves 30 toward a center-line of the membrane cartridge 120 to further increase the area accessible for the feed gas flow. In Figure 2A, the dividing walls 130 extend radially across the membrane cartridge 120 along the membrane cartridge's length. The dividing walls 130 are corrugated with grooves 30 directed through a length axis of the membrane cartridge 130. This is a non-limiting example of appropriate design and arrangement of the dividing walls 130 for separating the hollow fiber membranes 130 and improve efficiency of the membranes. However, the skilled designer may implement the dividing walls 130 alternatively within the inventive concept. For instance the number of dividing walls 130 and their dimensions, but also the dimensions and directions of the grooves 30 may be appropriately adapted to various needs.

The cross-sectional view in Figure 2C shows a cut (A-A) through the gas separation arrangement 100. The housing 110 is illustrated together with parts of the membrane cartridge 120 when inserted in the housing 110. The recess 134 of the second end part 124 is hidden but indicated as striped as it is located behind a rim 12 of the second end part 124. The hollow fiber membranes 128, the holes 132 between the rim 12 and the second chamber, and the distance parts 126 is further illustrated. In figure 2C is also the first gas connector 112 seen. The optional divisional walls 130 are also viewed and separate the hollow fiber membranes 128 in bundles, as disclosed above in conjunction with other embodiments.

As one can see in the Figures 2A and 2B, the illustrated gas separation arrangement, i.e. the membrane cartridge 120 together with the housing 110 is configured for shell-side membrane, i.e. the feed gas flow enters the tangentially arranged first gas connector 112 and is guided into the inlet chamber via the holes 132, the permeate gas flow will be outputted via the second gas connector 114, and the retentate gas flow will leave via the third gas connector 116. However, by arranging appropriate lids differently, instead, the gas separation arrangement may easily be configured for lumen-side membrane. Then the left side of the housing 110 is instead implemented as a lid with the fourth gas connector and the tangentially arranged gas connector is blocked.

With reference to the Figures 3A-3D, that are schematic illustrations, some examples of appropriate lids will now be described in accordance with exemplifying embodiments.

Figure 3A shows a sealing lid 302, which typically is arranged to seal the second end 2 of the gas separation arrangement described above when it is configured for shell-type filtering. Then the sealing lid 302 blocks the second ends of the hollow fibers, such that the permeate gas flow that passes the walls of the hollow fibers into the hollow fibers' lumens proceeds in the lumens into the outlet chamber.

Figure 3B shows a lid 304 with a second gas connector 114. The lid 304 will be arranged at the first end 1 of the gas separation arrangement, for either outputting the permeate gas flow when applying shell-side membrane, or for inputting the feed gas flow when applying lumen-side membrane. At shell-side filtering the second gas connector 114 is configured to output the permeate gas flow, but at lumen-side membrane the second gas connector 114 is configured to receive the feed gas flow. Thus, one and the same lid 304 may be adapted both for shell-side membrane and for lumen-side membrane, but the second gas connector changes its functionalities. The lid 304 may be provided with a recess (not seen) on the hidden side to constitute the second chamber shown in the figures 1A, and IB.

Figure 3C shows a lid 306 with a fourth gas connector (hidden in the figure). The lid 306 will be arranged at the second end of the housing 110 when the gas separation arrangement is configured for lumen-side filtering. The fourth gas connector is then configured to output the retentate gas flow. The fourth gas connector is arranged at an optional circular recess. The recess may be designed to collect the retentate gas flow from the hollow fibers' lumens. In the figure 3C, the optional excess part of the lid 306 is seen as an unfilled square. The excess part may be arranged for evenly distributing the feed gas flow on the lumen-side membrane. Finally, Figure 3D shows a lid 308 configured to block the tangentially arranged third gas connector. As described above, blocking the tangentially arranged third gas connector is made when configuring the gas separation arrangement for lumen-side membrane.

In the figures 3A-3D one can see fastening means implemented as through holes for screws or bolts. However, the proposed concept is not limited to implement the fastening means as through holes. A designer may apply alternative fastening means to fasten the appropriate lids 302, 304, 306, 308 at the various gas connectors.

With reference to Figure 4, which is a schematic cross-sectional view, a gas separation arrangement 100 will now be described in accordance with one exemplifying embodiment.

The gas separation arrangement 100 has been described above in other embodiments, but will here be described further according to a cross-sectional view along its length. The gas separation arrangement 100 is here configured for shell-type filtering, but is equipped with functionality to easy convert it for lumen-side membrane when desired. The gas separation arrangement 100 comprises the housing 110 and the membrane cartridge described above. In Figure 4, the membrane cartridge has been inserted into the housing 110. At the housing 110 two lids 302, 304 are arranged for configuring the gas separation arrangement for shell-side membrane. One can also see that an intermediate further lid 306 optionally has been arranged between the housing 110 and the sealing lid 302, to make conversion between shell-side membrane and lumen-side membrane. This will be further explained below.

In Figure 4, the membrane cartridge with its first end part 122, second end part 124, distance parts 126, and hollow fibers 128 is seen. The holes 132 that connects the third chamber (dispersion atrium) 106 and the first chamber 102 are illustrated, and also the second chamber 104. The optional dividing walls 130 and the recess 134 are further illustrated. The recess 134 constitutes here the third chamber 106 when the membrane cartridge has been arranged in the housing 110. The four gas connectors, i.e. the first gas connector 112, the second gas connector 114, the third gas connector 116, and the fourth gas connector 117 are also illustrated. In figure 4, the gas separation arrangement 100 is configured for shell-side membrane filtering as the lid 302 blocks the fourth gas connector 117. However, the gas separation arrangement can easily be converted for lumen-type filtering, by removing the lid 302 to open the fourth gas connector, and instead blocking the first gas connector 112, e.g. with the sealing lid referred to as 308 in figure 3D.

An advantage with arranging the intermediate lid 306 already is that the gas separation arrangement 100 may easily and convenient be re-configured from shell-side membrane filtering to lumen-side membrane filtering by replacing the lid 302 with the lid 306 and block the gas connector referred to as 112 in Figure 4. It is to be noted that in Figure 4, the dividing walls 130 have been illustrated as not reaching the housing's 100 interior. The space 4 lateral of the hollow membrane fibers is then emphasized. However, as explained above, the optional dividing walls 130 may be designed with different dimensions within the inventive concept and separate bundles of the hollow fiber lumens.

With reference to Figure 5, which is a schematic flow chart, a method of separating gases will now be described in accordance with one exemplifying embodiment.

In an initial action 502, a gas separation arrangement is formed by inserting a membrane cartridge into a cartridge port of a housing. The membrane cartridge comprises: a first end part; a second end part; a distance part; and a plurality of hollow fiber membranes, where each of the hollow fiber membranes is connected with a first end 1 to the first end part and a second end 2 to the second end part, such that the fibers' lumens can distribute gas through the first end part and the second end part. When the membrane cartridge is inserted a first end 1 of the membrane cartridge divides the housing in an inlet chamber and an outlet chamber.

In another action 504, a feed gas flow of a gas mixture is feed through a first gas connector into the inlet chamber. As defined above in conjunction with other embodiments, the gas mixture may comprise a desired gas, e.g. hydrogen, and other less desired gases to be filtered away.

In yet another action 506, the feed gas flow is filtered by membrane walls of hollow fibers. The membrane cartridge comprises a bundle of the hollow fibers. When the feed gas is separated by the membranes, the gas separation arrangement is configured to make use of the hollow fibers as either shell-side membranes, or lumen-side membranes. For shell-side membranes, the feed gas mixture is separated such that the desired permeate gas flow passes through the membrane fibers into the lumens, but the retentate gas flow remains in the inlet chamber. For lumen-side membranes, the situation is opposite, instead, the feed gas flow is feed into the lumens from the fibers' end openings. The desired permeate gas flows through the lumens' walls, but the retentate gas flow is prevented from passing through the fibers' walls. Instead, the retentate gas flow is guided through the lumens and out through the lumens opposite ends.

In another action 508, the permeate gas flow that has entered into the outlet chamber is outputted via the second gas connector as a now purified flow of the desired gas.

In yet another action 510, the retentate gas flow is outputted from the outlet chamber via the third gas connector.

It is to be noted that even if the actions 504 to 510 are defined above one by one, they are typically performed simultaneously in a sequence when separating gases.

The described method of separating gases may be implemented by applying the gas separation arrangement described above in conjunction with other embodiments. When applying shell-side membranes for filtering, the action 502 comprises: blocking the fibers' second ends; connecting both the first and third gas connectors to the inlet chamber; and connecting the second gas connector to the outlet chamber. When instead applying lumen-side membranes for filtering, the action 502 comprises: connecting the first and third gas connectors to the gas separation arrangement's respective ends; and connecting the second gas connector to the outlet chamber of the housing.

The described method of this embodiment may be implemented by making use of the earlier described gas separation arrangements of described in conjunction with above-described embodiments, with reference to the accompanying figures.

Reference throughout the specification to "one embodiment" or "an embodiment" is used to mean that a particular feature, structure or characteristic described in connection with an embodiment is included in at least one embodiment.

Thus, the appearance of the expressions "in one embodiment" or "in an embodiment" in various places throughout the specification are not necessarily referring to the same embodiment. Further, the particular features, structures or characteristics may be combined in any suitable manner in one or several embodiments. Although the present invention has been described above with reference to specific embodiments, it is not intended to be limited to the specific form set forth herein. Rather, the invention is limited only by the accompanying claims and other embodiments than the specific above are equally possible within the scope of the appended claims. Moreover, it should be appreciated that the terms "comprise/comprises" or "include/includes", as used herein, do not exclude the presence of other elements or steps.

Furthermore, although individual features may be included in different claims, these may possibly advantageously be combined, and the inclusion of different claims does not imply that a combination of features is not feasible and/or advantageous. In addition, singular references do not exclude a plurality. Finally, reference signs in the claims are provided merely as a clarifying example and should not be construed as limiting the scope of the claims in any way.

The scope is generally defined by the following independent claims. Exemplifying embodiments are defined by the dependent claims.

References

[1] N.Z. Muradov, T.N. Veziroglu, "Green" path from fossil-based to hydrogen economy: an overview of carbon-neutral technologies, Int J Hydrogen Energ. 33 (2008) 6804-6839.

[2] G. Marban, T. Valdes- Solis, Towards the hydrogen economy?, Int J Hydrogen Energ. 32 (2007) 1625-1637. [3] L. Shao, B.T. Low, T.S. Chung, A.R. Greenberg, Polymeric membranes for the hydrogen economy: contemporary approaches and prospects for the future, J. Membr. Sci. 327 (2009) 18-31.

[4] G. Lu, J.D. Da Costa, M. Duke, S. Giessler, R. Socolow, R. Williams, T. Kreutz, Inorganic membranes for hydrogen production and purification: a critical review and perspective, J. Colloid Interface Sci. 314 (2007) 589-603.

[5] H. Lin, E. Van Wagner, B.D. Freeman, L.G. Toy, R.P. Gupta, Plasticization-enhanced hydrogen purification using polymeric membranes, Science 311 (2006) 639-642.

NUMBERED EXEMPLIFYING EXAMPLES (NEEs):

NEE1. A membrane cartridge (120) configured to, together with a housing (110), form a gas separation arrangement (100) with an inlet chamber (102) and an outlet chamber (104) for separating a permeate gas flow from a gas mixture flow, the membrane cartridge (120) comprising:

• a first end part (122),

• a second end part (124),

• a distance part (126) connecting the first end part (122) and the second end part (124) with a fixed distance therebetween, and

• a plurality of hollow fibers (128), where each one of the hollow fibers (128) is connected with a first end (1) to the first end part (122) and a second end (2) to the second end part (124), the membrane cartridge (120) being configured to facilitate the gas separation arrangement (100) both to:

• separate the permeate gas flow out from the hollow fibers, through the hollow fibers' (128) walls, and

• separate a permeate gas flow into the hollow fibers through the hollow fibers' (128) walls. NEE2. The filter cartridge (120) according to NEE1, further comprising at least one dividing wall (130) configured to divide the hollow fibers (128) into at least two substantial parallel bundles, preferably at least four parallel bundles.

NEE3. The filter cartridge (120) according to NEE 2, wherein the dividing walls (130) are designed with a corrugated surface structure with radially directed grooves (30) towards a center-line of the filter cartridge (120).

NEE4. The filter cartridge (120) according to NEE 1, wherein the hollow fibers (128) comprises polymers, preferably of glassy or rubbery polymers from a group of: polyethersulfone, polysulfone, polyimide, Silicon rubber, Polyphenylene oxide, Cellulose acetate, Polyaramide.

NEE5. The filter cartridge (120) according to NEE 1, wherein the hollow fibers', outer diameters 0 are between 100 pm < 0 < 3000 pm.

NEE6. A gas separation arrangement (100) for separating a permeate gas flow from a gas mixture flow, the gas separation arrangement (100) comprising:

• a housing (110) comprising: a first gas connector (112); a second gas connector (114); a third gas connector (116); and a cartridge port (118), and

• a membrane cartridge (120) according to any previous claims, wherein the gas separation arrangement (100) is formed by inserting the membrane cartridge (120) into the cartridge port (118), such that the membrane cartridge's (120) first end part (122) divides the housing (110) in the inlet chamber (102) and the outlet chamber (104), wherein the first gas connector (114) is arranged to input the gas mixture flow into the inlet chamber (102), wherein the second gas connector (114) is arranged to output the permeate gas flow from the outlet chamber (104), and wherein the third gas connector (116) is arranged to output a retentate gas flow.

NEE7. The gas separation arrangement (100) according to NEE 6, configured to separate Hydrogen from the feed gas flow of a gas mixture.

NEE8. The gas separation arrangement (100) according to NEE 6 or 7, wherein the housing (110) comprises a cylinder-formed body with two ends, wherein the first gas connector (112), the second gas connector (114), and the third gas connector (116), respectively, are arranged either at a periphery of the cylinder-formed body or at any of the two ends.

NEE9. The gas separation arrangement (100) according to NEE 8, wherein at least one of the two ends comprises an interchangeable lid (302, 304, 306) configured to either seal the end, or output the retentate gas flow through the third gas connector (116) arranged at the lid (306), such that the gas separation arrangement (100) is enabled to be configured both for:

• shell-membrane filtering, where the lid (302) is a sealing lid blocking the fibers' (128) second ends, and the permeate gas flow is filtered into the fibers (128), and

• lumen-membrane filtering, where the lid (304, 306) outputs the retentate gas flow through the third gas connector (116), and the permeate gas flow is filtered out of the fibers (128).

NEE10. The gas separation arrangement (100) according to anyone of the NEEs 6 to 9, wherein the filter cartridge's (120) second end part (124) is configured to divide a dispersion atrium (106) from the inlet chamber (102), where the dispersion atrium (106) is connected with the inlet chamber (102) via a plurality of holes (132) through the membrane cartridge's (120) second end part (124), and wherein the first inlet (112) is arranged to input the gas mixture via the dispersion atrium (106) into the inlet chamber (102), such that the gas mixture could be filtered by the hollow fibers' (128) walls, resulting in the permeate gas flow into the hollow fibers' (128) lumens and a retentate gas flow through the inlet chamber(102), wherein the permeate gas flow is guided by the hollow fibers lumens into the outlet chamber (104), and the retentate gas flow is outputted by the third gas connector (104).

NEE11. The gas separation arrangement (100) according to NEE 10, wherein the membrane cartridge's (120) second end part (124) is provided with a circumferential recess (134) about a periphery thereof, and the first inlet (112) is tangentially arranged to the dispersion atrium (106), such that the gas mixture flow is guided by the recess (134) in a whirl before entering the plurality of holes (132).

NEE12. The gas separation arrangement (100) according to anyone of the NEEs 6 to 9, configured to guide the gas mixture through the hollow fibers' (128) lumens from the inlet chamber (102) to be filtered by the hollow fibers' (128) walls, resulting in a permeate gas flow out from the hollow fibers' lumens and a retentate gas flow further through the hollow fibers' (128) lumens.

NEE13. A method of separating a permeate gas flow from a feed gas flow of a gas mixture, using a gas separation arrangement comprising a housing and a membrane cartridge, the housing comprising: a first gas connector; a second gas connector; a third gas connector; and a cartridge port, and the membrane cartridge comprising; a first end part; a second end part; and a plurality of hollow fibers connecting the first end part and the second end part, such that the hollow fibers' lumens constitute openings through the first end part and the second d end part, respectively, the method comprising:

• forming (502) the gas separation arrangement by inserting the membrane cartridge into the cartridge port, such that a first end part of the membrane cartridge divides the housing into an inlet chamber and an outlet chamber,

• inputting (504) the feed gas flow in the inlet chamber via the first gas connector,

• filtering (506) the feed gas flow through the hollow fiber walls, resulting in a permeate gas flow to the outlet chamber, and a retentate gas flow,

• outputting (508) the permeate gas flow from the outlet chamber via the second gas connector, and

• outputting (510) the retentate gas flow from the inlet chamber via the third gas connector.

NEE14. The method according to NEE 13, where the fibers' lumens are blocked in their second ends, wherein filtering (506) the feed gas flow comprises passing the permeate gas flow into the fibers' lumens through the fibers' walls, while preventing the retentate gas flow from entering the fibers' lumens, and wherein outputting (508) the permeate gas flow comprises guiding the filtered permeate gas flow via the fibers' lumens into the outlet chamber.

NEE15. The method according to NEE 13, where the fiber lumens' are connected to the third gas connector, and wherein filtering (506) comprises passing the permeate gas flow out of the fibers' lumens through the fibers' walls, while preventing the retentate gas flow to leave the fibers' lumens through the fibers' walls, and wherein outputting (510) the retentate gas flow comprises guiding the retentate gas flow via the fibers' lumens to the third gas connector.

Claims

1. A membrane cartridge (120) for separating gas, comprising:

• a first end part (122), arranged at a first end (1) of the membrane cartridge (120);

• a second end part (124), arranged at a second end (2) of the membrane cartridge (120);

• a distance part (126) connecting the first end part (122) and the second end part (124) with a fixed distance therebetween;

• a plurality of hollow fiber membranes (128) extending from the first end part (122) to the second end part (124), wherein each one of the hollow fiber membranes (128) is connected with a first end to the first end part (122) and a second end to the second end part (124); and

• a space (4) arranged at a lateral side (28) of the plurality of hollow fiber membranes (128) and between the first end part (122) and the second end part (124); wherein the second end part (124) comprises a recess (134) arranged at a lateral side

(24) of the second end part (124) and at least one hole (132) extending from the space (4), through the second end part (124), to the recess (134); wherein the recess (134) is in fluid connection with the space (4), via the at least one hole (132); and wherein the first end (1) of the membrane cartridge (120) is in fluid connection with the second end (2) of the membrane cartridge (120) via the hollow fiber membranes (128).

2. The membrane cartridge (120) of claim 1, wherein an axis of the at least one hole deviates from a direction perpendicular to the hollow fiber membranes (128).

3. The membrane cartridge (120) of any one of the preceding claims, wherein the second end part (124) comprises a rim (12), wherein the rim (12) extends around the hollow fiber membranes and overhangs the space (4) such that the space (4) extends around the hollow fiber membranes (128), wherein the at least one hole (132) is arranged in the rim (12).

4. The membrane cartridge (120) of claim 3, wherein an outer diameter of the rim (12) is at least 10% larger than an inner diameter of the rim (12).

5. The membrane cartridge (120) of any one of the preceding claims, wherein the recess (134) is a circumferential recess (134) about a periphery of the second end part (124).

6. The membrane cartridge (120) of any one of the preceding claims, wherein the at least one hole (132) comprises at least six holes.

7. The membrane cartridge (120) of any one of the preceding claims, wherein the plurality of hollow fiber membranes (128) comprises at least a first and a second bundle of hollow fiber membranes (128); and a passage (14) extending from the space (4) at the lateral side (28) of the plurality of hollow fiber membranes (128) and in-between the first and second bundle of hollow fiber membranes (128).

8. The membrane cartridge (120) of claim 7, further comprising a dividing wall (130) arranged between the first and second bundle of hollow fiber membranes (128), the dividing wall (130) having a corrugated surface comprising at least one groove (30), the at least one groove (30) extending from the space (4) at the lateral side (28) of the plurality of hollow fiber membranes (128) and in-between the first and second bundle of hollow fiber membranes (128) such that the at least one groove (30) forms the passage The membrane cartridge (120) of any one of the preceding claims, wherein the hollow fiber membranes (128) comprises polymers, preferably of glassy or rubbery polymers from a group of: polyethersulfone, polysulfone, polyimide, Silicon rubber, Polyphenylene oxide, Cellulose acetate, Polyaramide. The membrane cartridge (120) of any one of the preceding claims, wherein the hollow fiber membranes (128) have outer diameters in a range of 100 pm to 3000 pm. A gas separation arrangement (100) for separating gas, comprising:

• a housing (110) comprising: a first gas port (112) and a cartridge port (118); and

• a membrane cartridge (120) according to any one of the previous claims, wherein the housing (110) is configured to receive the membrane cartridge (120) by the cartridge port (118); wherein the first end part (122) of the membrane cartridge (120), the second end part (124) of the membrane cartridge (120), and a lateral side wall (10) of the housing (110) are configured to form a chamber (102) when the membrane cartridge (120) is received by the cartridge port (118), the space (4) at the lateral side (28) of the plurality of hollow fiber membranes (128) of the membrane cartridge (120) being at least part of the chamber (102); wherein the first gas port (112) is arranged to connect to the recess (134) at the lateral side (24) of the second end part (124) of the membrane cartridge (120), when the membrane cartridge (120) is received by the cartridge port (118), such that the first gas port (112) comes into fluid connection with the chamber (102) via the recess (134) and the at least one hole (132). The gas separation arrangement (100) of claim 11, wherein, when the membrane cartridge (120) is received by the cartridge port (118): a cross section of the chamber (102) comprises an inner area through which the hollow fiber membranes (128) extend, the inner area being less than 85% of a full area of the cross section of the chamber (102), the cross section being perpendicular to the hollow fiber membranes (128). The gas separation arrangement (100) of claim 11 or 12, wherein the housing (110) comprises a recess (34) configured to align with the recess (134) at the lateral side (24) of the second end part (124) of the membrane cartridge (120), when the membrane cartridge (120) is received by the cartridge port (118), the recess (34) of the housing being in fluid connection with the first gas port (112) such that the first gas port (112) comes into fluid connection with the recess (134) at the lateral side (24) of the second end part (124) of the membrane cartridge (120) via the recess (34) of the housing (110). The gas separation arrangement (100) of any one of claims 11-13, wherein the housing comprises a second gas port (114) arranged to be in fluid connection with an inside of the hollow fiber membranes, when the membrane cartridge (120) is received by the cartridge port (118).