Arrangement configuration for joining and sealing a metal hydrogen separation membrane to a metal connector

Abstract

The present invention provides a joining and sealing arrangement for joining a hydrogen separation membrane to a metal connector and sealing them together, the joining and sealing arrangement comprising: a metal hydrogen separation membrane mounted on or applied to a connector around a longitudinal axis, the connector being formed of a metal different from that of the hydrogen separation membrane, the hydrogen separation membrane having an outer diameter (D) around the longitudinal axis, and the hydrogen separation membrane and the connector forming part being in contact at a connection interface where the end face of the hydrogen separation membrane is near, substantially abutting, or overlapping the adjacent face of the connector forming part; a connecting part connecting the hydrogen separation membrane and the connector forming part around the connection interface; a constriction collar extending at least from the connection interface and configured to extend axially covering the hydrogen separation membrane with respect to the longitudinal axis, the constriction collar including an expansion section configured to extend axially covering the hydrogen separation membrane from a constriction end to an expansion diameter with respect to the longitudinal axis, the constriction end being configured to extend around the hydrogen separation membrane at or near the connection interface with respect to the longitudinal axis and having an inner surface defining a constriction diameter (C) configured to extend around the outer surface of the hydrogen separation membrane, the expansion section including a transition section extending from the constriction end and having a curved surface with a transition radius of at least 0.1D, the expansion section including a angled or curved section where the diameter of the constriction collar expands from the constriction diameter C to an expansion diameter including a diameter of at least 1.01D; and comprising.

Description

Technical Field

[0001] Cross - reference to Priority of Related Applications This application claims priority from Australian Provisional Patent Application No. 2022901905, filed on July 7, 2022, the content of which is to be incorporated herein by reference.

[0002] The present invention generally relates to an arrangement for joining and sealing a metallic hydrogen separation membrane to a metal connector. In particular, the present invention is particularly applicable for joining and sealing a vanadium - based tubular membrane to a stainless - steel gas joint. However, it should be understood that the present invention can be used for joining and sealing any metal - type hydrogen separation membrane to any type of metal joint or body part.

Background Art

[0003] The following description of the background art of the present invention is intended to facilitate understanding of the present invention. However, it should be understood that this description is not an admission or acknowledgment that any of the materials mentioned were published, known, or part of common general knowledge at the priority date of this application.

[0004] Hydrogen (H2) does not occur naturally in large quantities and is industrially produced by the conversion of hydrocarbon fuels such as coal, oil, or natural gas, through the decomposition of ammonia (NH3), or from the electrochemical decomposition of water. Each of these production routes generates an impure gas stream containing, in addition to H2, unreacted feed gas (e.g., CH4, H2O, NH3) and by - products such as CO2, CO, and N2. For many applications, H2 must be separated from this mixed gas stream.

[0005] Membrane-based separation technologies can be used for the separation of H2 from a mixed gas stream. Broadly speaking, a membrane is a nearly two-dimensional structure that has selective permeability to one chemical species. In the context of gas separation, a membrane allows one chemical species (H2) to selectively permeate while blocking the permeation of the other chemical species (e.g., CO, CO2, H2O, N2, etc.). Hydrogen-selective membranes are often formed from inorganic materials, metallic materials, or ceramic materials, each of which has characteristic hydrogen processing capabilities, operating temperatures, and selectivities.

[0006] Palladium is the most well-known alloy membrane material, having the ability to permeate hydrogen at temperatures between 300 and 600 °C and being resistant to syngas species such as CO and H2O. However, due to the high cost of palladium ($100 - 130 per gram of Pd as of May 2022), research is being carried out in the direction of minimizing the consumption of palladium, most notably through alloying with less expensive metals, and in the direction of minimizing the thickness by depositing a very thin (<5 μm) layer on a support structure with very fine micropores.

[0007] A number of other metals have shown very high hydrogen permeability, most notably vanadium, titanium, tantalum, niobium, and zirconium. At 400 °C, the hydrogen permeability of these metals is approximately two orders of magnitude greater than that of palladium, and the raw material prices are significantly lower. Among these metals, vanadium has the widest alloying range, meaning there is the most room to modify the alloy properties to meet the requirements of vanadium-based membranes. An example of a vanadium-based membrane is taught in Applicant's U.S. Patent Application Publication No. 20150368762A1.

[0008] Vanadium-based membranes are typically connected and sealed to another tube or pipe so as to provide a flow path for the extracted H2 and prevent the passage of non-H2 gas species through the membrane. The sealing / joining of the membrane and the connection is extremely important for the successful application of V-based membrane technology in separating high-purity hydrogen from a mixed gas feed stream containing hydrogen. In this regard, high-purity hydrogen suitable for use in fuel cell electric vehicles (FCEVs) requires a purity of >99.97% as defined by the ISO14687 standard, and further requires defining maximum limits for individual gas species such as NH3 and N2. If there are seal failures, contamination of the hydrogen product occurs and those membranes are no longer "fit for purpose" for high-purity hydrogen production.

[0009] One technique for the connection and sealing of tubular vanadium-based membranes utilizes brazing or welding the connection between the V-based membrane and a metal fitting, such as an end cap or connection fitting. An example of an arrangement for joining a vanadium-based membrane to a metal fitting is taught in International Publication No. WO 2019 / 000026 A1, which teaches a brazing technique for joining and sealing a vanadium-based membrane to a metal connector using a filler or brazing metal to form a filler metal bridge section on the connection interface between the vanadium-based membrane and the connector.

[0010] An example of a welding arrangement for joining a vanadium-based membrane to a metal fitting is taught in V.N. Alimov, I.V. Bobylev, A.O. Busnyuk, S.N. Kolgatin, S.R. Kuzenov, E.Yu. Peredistov, A.I. Livshits. International Journal of Hydrogen Energy, Volume 43, Issue 29, July 19, 2018, pages 13318 - 13327. The illustrated arrangement appears to use a small bridging collar that sits on top of the vanadium-based membrane and the abutting metal fitting, which is then sealed, for example by arc welding, to join the vanadium-based membrane to the abutting metal fitting.

[0011] However, vanadium-based hydrogen separation membrane tubes can have a linear (dimensional) expansion of up to about +5% and a volume expansion of up to about +15% when hydrogenated at conventional operating temperatures and pressures compared to ambient conditions without hydrogen. Other Group 5 metals also have similar hydrogenation expansion characteristics. None of the above-described joining arrangements adequately account for the linear and volume expansion of these types of metal hydrogen separation membranes when exposed to hydrogen, and the strains and stresses that can affect the integrity of the seal and the joint around the sealed joint. In each case, the brazed or welded joint is not protected from the volume expansion of the metal hydrogen separation membrane adjacent to the joint.

[0012] Therefore, it would be desirable to provide an improved and / or alternative method of connecting and sealing a tube-shaped membrane based on vanadium or a vanadium alloy to an adjacent metal tube or pipe.

Prior Art Documents

Patent Documents

[0013]

Patent Document 1

Patent Document 2

Non-Patent Document

[0014]

Non-Patent Document 1

Summary of the Invention

Problems to be Solved by the Invention

[0015] The present invention provides a joining and sealing arrangement for joining a hydrogen separation membrane to a metal connector and sealing them together, including a constriction collar for joining a metal hydrogen separation membrane to a metal joint, such as a stainless - steel joint, and sealing them together, as well as a hydrogen separation membrane constriction collar.

Means for Solving the Problems

[0016] A first aspect of the present invention provides a joining and sealing arrangement for joining a hydrogen separation membrane to a metal connector and sealing them together, the sealing arrangement comprising: a metal hydrogen separation membrane mounted on or applied to a connector forming part around a longitudinal axis, the connector being formed of a metal different from the hydrogen separation membrane, the hydrogen separation membrane having an outer diameter (D) around the longitudinal axis, and the hydrogen separation membrane and the connector forming part being in contact at a connection interface where the end face of the hydrogen separation membrane is near, substantially in contact with, or overlapping the adjacent face of the connector forming part; a connection part connecting the hydrogen separation membrane and the connector forming part around the connection interface; a constriction collar extending at least from the connection interface and configured to extend axially covering the hydrogen separation membrane with respect to the longitudinal axis; An expansion section configured to extend axially covering a hydrogen separation membrane with respect to the longitudinal axis from a narrow end to an expansion diameter, the narrow end being configured to extend around the hydrogen separation membrane at or near the connection interface with respect to the longitudinal axis, having an inner surface defining a narrow diameter (C) configured to extend around the outer surface of the hydrogen separation membrane, the expansion section comprising a narrow collar and comprising The expansion section includes a transition section extending from the narrow end, the transition section including a curved surface having a transition radius of at least 0.1D, The expansion section includes a section angled or curved such that the diameter of the narrow collar expands to an expansion diameter including a diameter of at least 1.01D from the narrow diameter.

[0017] The inventors have found that the connection between the metal hydrogen separation membrane and the connector itself tends to be defective (resulting in leakage) and may not have the desired robustness against changes in membrane hydrogenation. The joining and sealing arrangement in the first aspect of the present invention is designed to restrict the volumetric expansion of the connection joint between the hydrogen separation membrane and the connector or of the metal hydrogen separation (hydrogen selectivity) tubular membrane near it when exposed to hydrogen. The narrow collar of this joining and sealing arrangement allows the hydrogenated hydrogen separation membrane to expand from the narrow diameter at the narrow end of the expansion section to its natural hydrogenated expansion diameter as the hydrogen separation membrane extends away from the connection between the hydrogen separation membrane and the connector along the longitudinal axis within the narrow collar, preferably expanding gradually or progressively to a larger expansion diameter transitioning to an expansion section.

[0018] The constricted end of the constricted collar comprises a constricted section configured to move the expansion zone of the hydrogen separation membrane away from the connection interface / junction, thereby reducing the strain on its welded joint. In these embodiments, the constricted section is configured to extend axially covering the hydrogen separation membrane from the connection end with respect to the longitudinal axis towards the expansion section, and the constricted section has an inner surface extending around the longitudinal axis with a constricted diameter. Here, the transition section extends from the transition region, area, or point where the constricted section contacts the expansion section.

[0019] It should be understood that the transition section includes a curved surface that forms the transition surface of the expansion section of the collar from the constricted end / constricted section. The curved surface has a curvature following a radial curvature of at least 0.1D. This curvature typically includes only a short segment or portion of its radial curvature, and it should be understood that the curvature joins the ends of the transition surface between the constricted end / constricted section and the expansion section and forms the transition surface.

[0020] When hydrogen is introduced into the hydrogen separation membrane, the hydrogenated hydrogen separation membrane expands within the constricted collar and within the constricted section, and its expansion is restricted by the limits of the inner surface of the constricted collar. The collar of this first aspect of the invention is configured to increase the size of the region where constriction-induced stress occurs along the hydrogen separation membrane. Instead of stress concentrating at or near the interface, the stress load is moved away from the connection interface and spread along the entire constricted section. This reduces the stress load on the connection interface and spreads the magnitude of the stress over the entire constricted collar rather than at a single point of the connection interface. Thus, the collar enables the seal between the hydrogen separation membrane and the connector to remain intact without being impaired even when there are changes in the expansion and contraction it undergoes when the membrane hydrogenation changes.

[0021] The outer diameter D should be understood as the outer diameter of the hydrogen separation membrane when the hydrogen separation membrane is in an unhydrogenated state (i.e., not in a hydrogenated and expanded state). The outer diameter depends on the size of the membrane used for hydrogen separation and can thus have any suitable dimension. In embodiments, the outer diameter (D) can be from 2 mm to 25 mm. In some embodiments, the outer diameter (D) of the hydrogen separation membrane is from 5 mm to 20 mm, preferably from 7 mm to 15 mm, and more preferably from 8 mm to 12 mm. In some embodiments, the outer diameter (D) of the hydrogen separation membrane is from 8.5 mm to 10 mm, preferably from 9 mm to 10 mm, and more preferably about 9.5 mm. In some embodiments, the outer diameter (D) can be from 25 mm to 1000 mm, preferably from 25 mm to 100 mm. In other embodiments, the outer diameter (D) can be from 100 mm to 1000 mm, preferably from 200 mm to 800 mm.

[0022] The narrow diameter C is preferably sized between 0.95D and 1.05D. In embodiments, the narrow diameter includes diameters from 0.97D to 1.05D, preferably from 0.99D to 1.05D, and more preferably from 1D to 1.05D. In some embodiments, the narrow diameter includes diameters from 0.98D to 1.05D, preferably from 0.999D to 1.05D. In some embodiments, the narrow diameter includes diameters from 1D to 1.04D, preferably from 1D to 1.02D, and more preferably from 1.005D to 1.01D. In some embodiments, the narrow diameter is sized to fit snugly (from 0.95D to 1D), and force is required to fit the narrow end of the expansion section and (in applicable embodiments) the narrow section covering the hydrogen separation membrane. In other embodiments, the narrow diameter is sized to be larger than the outer diameter of the hydrogen separation membrane such that the narrow end of the expansion section and (when applicable) the narrow section are fitted, preferably slidably fitted, over the hydrogen separation membrane. In these embodiments, it should be understood that when the hydrogen separation membrane is in the unhydrogenated state, the narrow diameter of the inner surface of the narrow end and (in applicable embodiments) the narrow section are preferably spaced from the outer surface (having an outer diameter D) of the hydrogen separation membrane. The inner surface of the narrow section abuts or engages the outer surface of the hydrogen separation surface when the hydrogen separation membrane is in the hydrogenated state. The narrow diameter is preferably configured such that the inner surface of the narrow section is spaced from the unhydrogenated hydrogen separation membrane and can fit therein without the membrane interfering. However, the gap is preferably designed to be small enough to limit the expansion of the hydrogen separation membrane relative to a set distance from the connection interface, such that the hydrogen separation membrane does not expand significantly enough to be subject to distortion or other undesirable forces that could affect the integrity of the seal formed by the connection if the connection were otherwise.

[0023] The inner surface of the narrow section is preferably spaced substantially parallel from the outer surface of the hydrogen separation membrane. In embodiments, the narrow diameter is greater than 1D. This spacing provides at least a small clearance that allows the hydrogen separation membrane and the connector to fit within the narrow collar. The narrow diameter typically has an upper limit on the ability to reduce, preferably substantially limit, movement of the hydrogen separation membrane around the connection between the hydrogen separation membrane and the connector even when changes in expansion and contraction occur when changes occur in membrane hydrogenation. In embodiments, the narrow diameter includes diameters greater than 1D to 1.05D, preferably greater than 1D to 1.04D, more preferably greater than 1D to 1.02D. In certain embodiments, the narrow diameter includes diameters from 1.005D to 1.01D. In other embodiments, the narrow diameter is greater than 1D to 1D + 0.05 mm, preferably greater than 1D to 1D + 0.04 mm.

[0024] The expansion diameter D2 is selected to be greater than the outer diameter D of the metal hydrogen separation membrane. In this sense, the expansion diameter D2 is sized larger than the outer diameter D of the metal hydrogen separation membrane when the metal hydrogen separation membrane is in the unhydrogenated state. In embodiments, the expansion diameter D2 is at least 1.01D, preferably at least 1.02D. In some embodiments, the expansion diameter D2 is selected to be greater than the maximum diameter of the hydrogen separation membrane after hydrogenation (diameter D MH )). Hydrogen separation hydrogen-selective membrane tubes, such as vanadium-based hydrogen separation membranes, can expand by at least +10% and more typically +13% in volume when hydrogenated at conventional operating temperatures / pressures compared to ambient conditions without hydrogen, and the linear expansion in one direction / axis can be up to 5%, for example up to the diameter. In embodiments, the expansion diameter D2 is thus at least 1.05D to accommodate the linear expansion upon hydrogenation of the hydrogen separation membrane. In embodiments, the expansion diameter D2 is at least 1.07D, preferably at least 1.08D, more preferably at least 1.1D. In some embodiments, the expansion diameter D2 is at least 1.12D, preferably at least 1.2D.

[0025] It should also be understood that the expansion diameter D2 is greater than the constriction diameter C of the constriction section of the constriction collar. In this sense, the expansion diameter D2 is of a size greater than the constriction diameter C. In an embodiment, the expansion diameter D2 is at least 1.01C, preferably at least 1.02C. In an embodiment, the expansion diameter D2 is at least 1.05C so as to accommodate the linear expansion upon hydrogenation of the hydrogen separation membrane (as described above). In an embodiment, the expansion diameter D2 is at least 1.07C, preferably at least 1.08C, more preferably at least 1.1C. In some embodiments, the expansion diameter D2 is at least 1.12C, preferably at least 1.2C.

[0026] The maximum diameter of the hydrogen separation membrane after hydrogenation, diameter D MH will also be greater than the constriction diameter C of the constriction section of the constriction collar. Similarly, the maximum diameter of the hydrogen separation membrane after hydrogenation, diameter D MH will also be greater than the outer diameter D of the metal hydrogen separation membrane when the metal hydrogen separation membrane is in the unhydrogenated state -- which can be understood from the nature of the hydrogenation process itself.

[0027] The diameter of the hydrogen separation membrane after hydrogenation, diameter D H should be understood to vary throughout the joining and sealing arrangement configuration depending on the placement of the hydrogen separation membrane within the constriction collar. For example, within the constriction section, the diameter D H is restricted to the constriction diameter C, but in the expansion section, the diameter D H is the maximum diameter of the hydrogen separation membrane after hydrogenation, diameter D MH until it reaches the diameter, diameter D MH it follows.

[0028] The expansion section can generally have a linear, curved, or other shaped or undulating surface that expands from a constricted diameter to an expanded diameter. As described above, the function of the expansion section is such that as the hydrogen separation membrane extends away from the connection between the hydrogen separation membrane and the connector along the longitudinal axis within the constriction collar, the hydrogenated hydrogen separation membrane expands from the constricted diameter at the constricted end of the expansion section to its natural hydrogenated expanded diameter, preferably providing a transition to a larger expanded diameter that allows it to expand gradually or progressively. The shape can have non-uniform or irregular shapes or undulations. However, the shape is generally preferably regular and / or smooth, for example, a region / surface along a transition section that includes a linear expansion angle or a smooth curve. If the expansion section includes a curve, the curve can include a continuous curve that includes the curve of the transition section. In some embodiments, the transition section can follow the same or a similar curve as the entire surface of the expansion section and share a common radius. Here, the angled or curved section of the transition section and the expansion section following the transition section can have the same or a similar curve and share a common radius.

[0029] The change from the constricted diameter to the expanded diameter within the expansion section can have any suitable shape or configuration. In some embodiments, the expansion section comprises an inclined or curved surface extending from the transition section to the expanded diameter. In an embodiment, the expansion section comprises a tapered surface. In an embodiment, the expansion section comprises a corrugated surface. For example, the diameter of the constriction collar can be configured to expand at an average expansion angle with respect to the longitudinal axis that includes an angle of less than 17.5 degrees (i.e., an angle from greater than zero degrees to 17.5 degrees), preferably from 0.5 degrees to 6 degrees, more preferably from 3 degrees to 5 degrees, from the constricted diameter to the expanded diameter within the expansion section. In some embodiments, the diameter of the constriction collar can be configured to expand at an average expansion angle with respect to the longitudinal axis that includes an angle of less than 15 degrees, preferably less than 10 degrees (i.e., an angle from greater than zero degrees to 10 degrees), preferably from 1 degree to 10 degrees, more preferably from 3 degrees to 6 degrees, even more preferably from 4 degrees to 5 degrees, from the constricted diameter to the expanded diameter within the expansion section. In other embodiments, the diameter of the constriction collar can be configured to expand at an average expansion angle with respect to the longitudinal axis that is at least 1 degree, preferably from 1 degree to 17.5 degrees, more preferably from 1 degree to 15 degrees, even more preferably from 2 degrees to 7 degrees, from the constricted diameter to the expanded diameter within the expansion section.

[0030] The average expansion angle should be understood to include the average growth rate or average growth rate of the expansion section. In embodiments where the expansion section has a linear slope, this substantially corresponds to the angle formed by that linear slope with respect to the longitudinal axis. In embodiments where the expansion section is curved or otherwise non-linear, the average expansion angle is the average or mean angle formed by the surface within that expansion section with respect to the longitudinal axis. For example, in a curved surface, the average expansion angle is the average angle of that curvature. In embodiments, the average expansion angle is a non-zero angle less than 17.5 degrees (i.e., an angle from greater than zero degrees to 17.5 degrees), preferably from 0.5 degrees to 6 degrees, more preferably from 3 degrees to 5 degrees. In some embodiments, the average expansion angle is a non-zero angle less than 15 degrees, preferably a non-zero angle less than 10 degrees (i.e., an angle from greater than zero degrees to 10 degrees), preferably from 1 degree to 10 degrees, more preferably from 3 degrees to 6 degrees, even more preferably from 4 degrees to 5 degrees. In some embodiments, the average expansion angle is from 1 degree to 17.5 degrees, preferably from 1 degree to 15 degrees, more preferably from 1 degree to 12 degrees, even more preferably from 2 degrees to 10 degrees, even more preferably from 2 degrees to 7 degrees. In some embodiments, the average expansion angle is from 3 degrees to 10 degrees, preferably from 3 degrees to 7 degrees. In some embodiments, the expansion angle is at least 3 degrees, more preferably at least 5 degrees. In some embodiments, the average expansion angle is about 5 degrees. The length of the expansion section can then be determined by the expansion angle and the size of the expansion diameter that the tapered portion must reach.

[0031] The length of the constricted section of the narrow color is preferably selected to provide a sufficient spacing of the connection interface from the expansion section, thereby reducing movement and other force transmissions from the expansion and contraction changes experienced when the membrane hydrogenation changes. In embodiments, the constricted section is configured to extend over the hydrogen separation membrane from the connection interface to the transition section for at least 0.25D. In some embodiments, the constricted section is configured to extend over the hydrogen separation membrane from the connection interface to the transition section for 0.25D to 2D, preferably 0.25D to 1.5D, more preferably 0.25D to 1D.

[0032] The expansion section is a section where the hydrogen expansion of the hydrogen separation membrane can preferably expand gradually to the maximum expansion diameter D over the length of the hydrogen separation membrane (with respect to the longitudinal axis). As a result of rapid expansion, stress-rising regions can still occur within the hydrogen separation membrane. Therefore, the expansion section preferably extends by at least 0.2D with respect to the longitudinal axis. The longer the length, the more advantageous it can be. Therefore, in embodiments, the expansion section extends by at least 0.3D, preferably at least 0.4D, more preferably at least 0.5D with respect to the longitudinal axis. MH Also, it should be understood that the transition section (and its surface) is arranged at the transition to a tapered or curved section (i.e., a tapered or curved surface) with an angle or curvature from the constricted diameter to the expansion section. In embodiments, the average expansion angle includes the curvature provided by the transition section (and the transition radius provided).

[0033]

[0034] As detailed above, when hydrogen is introduced into the hydrogen separation membrane, the hydrogenated hydrogen separation membrane (tube) expands within the constriction collar, and the expansion is restricted by the limits of the inner surface of the constriction collar. In the constriction section, the outer surface of the hydrogen separation membrane abuts and engages against the inner wall of that section. Similarly, the outer surface of the hydrogen separation membrane abuts and engages against the inner wall of the expansion section until it reaches the point where it attains the natural hydrogen expansion diameter of the hydrogen separation membrane. In the transition section, the outer surface of the hydrogenated hydrogen separation membrane has a complementary shape / curvature at around from the constriction diameter to the angled or curved section of the expansion section (i.e., the tapered or curved surface). Here, the membrane expands from the constriction diameter to the angled or curved portion of the collar's expansion section according to the shape of the transition section. Thus, the transition section provides a curved surface configured to prevent the formation of stress concentration points when the inner surface of the constriction collar transitions to the angled or curved portion (i.e., the tapered or curved surface) from the constriction diameter. The curved surface of the transition section preferably has a radius of curvature of at least 0.1D. In embodiments, the transition radius includes a radius from 0.1D to 10D, preferably from 0.5D to 5D, more preferably from 1D to 5D. In some embodiments, the transition radius includes a radius from 0.5D to 10D, more preferably from 1D to 10D, more preferably from 2D to 10D.

[0035] The constricted collar is designed to extend from and preferably cover the connection interface of the hydrogen separation membrane. In an embodiment, the constricted section of the constricted collar is configured to extend covering the connection interface. In an embodiment, the constricted collar can also be configured to extend covering the connection interface and at least a portion of the connector. As taught above, the constricted diameter is preferably sized between 0.95D and 1.05D. In an embodiment, the constricted diameter includes diameters from 0.97D to 1.05D, preferably from 0.99D to 1.05D, and more preferably from 1D to 1.05D. In some embodiments, the constricted diameter includes diameters from 0.98D to 1.05D, preferably from 0.999D to 1.05D. In other embodiments, the constricted diameter includes diameters from 1D to 1.04D, preferably from 1D to 1.02D, and more preferably from 1.005D to 1.01D. However, in some embodiments, the inner surface of this portion of the constricted section is preferably spaced substantially parallel from the outer surface of the connection interface and the connector. In these embodiments, the inner diameter (constricted diameter) of this portion of the constricted section is greater than 1D to 1.05D, preferably greater than 1D to 1.04D, more preferably greater than 1D to 1.02D. In a particular embodiment, the constricted diameter includes diameters from 1.005D to 1.01D. In some embodiments, the inner diameter (constricted diameter) of this portion of the constricted section is at least greater than 1D, more preferably from greater than 1D to 1D + 0.05 mm. Thus, the constricted section can mechanically restrict any expansion of the connection interface during hydrogenation expansion and cyclic operation. It should be understood that the cyclic operation refers to the phase of expansion and contraction of the hydrogen separation membrane during operation.

[0036] In an embodiment, the constriction collar includes a collar fastening section configured to fasten onto a section of the connector. The constriction collar is preferably configured to extend over the connection interface up to the constriction collar fastening section. Typically, the constriction collar extends from the constricted end over the connection interface up to the constriction collar fastening section. The constriction collar fastening section typically comprises a fastening formation configured to interconnect the constriction collar with a cooperating fastening formation of the connector. It should be understood that the cooperating fastening formation includes a thread, inter-engageable ribs and grooves, a rib and slot configuration, a quick lock configuration, or other suitable inter-engaging fastening configurations. In some embodiments, the fastening formation comprises a threaded connection portion configured to cooperatively fasten onto a thread disposed on the connector.

[0037] In an embodiment, the constriction collar further comprises an end cap configured to form an end seal around the connector. The end cap preferably comprises a sealing cap for sealing one end of the hydrogen separation membrane when the connector is fastened. In some embodiments, the end cap extends from the connection interface, preferably covering the connection interface, around the end of the connector distal to the connection interface. Typically, the end cap extends from the constricted section, covering the connection interface, around the end of the connector distal to the connection interface. The end cap preferably comprises a fastening formation configured to interconnect the constriction collar with a cooperating fastening formation of the connector. It should be understood that the cooperating fastening formation includes a thread, inter-engageable ribs and grooves, a rib and slot configuration, a quick lock configuration, or other suitable inter-engaging fastening configurations. In some embodiments, the fastening formation comprises a threaded connection portion configured to cooperatively fasten onto a thread disposed on the connector.

[0038] In an embodiment, the connector includes a tubular extension that extends longitudinally away from the connection interface with respect to the longitudinal axis. Here, the constriction collar includes a sealing section configured to cover the tubular extension of the connector and extend to the distal fastening end. Typically, the sealing section extends from the constriction section to cover the connection interface and extend to the distal fastening end. The constriction collar in this embodiment further includes a compression fitting configured to fasten to the distal fastening end of the sealing section, and at least one ferrule configured to seal around one section of the tubular extension of the connector when the compression fitting is fastened to the distal fastening end of the sealing section. The ferrule includes a sealing member that is compressed by the compression fitting to form a fluid seal between the compression fitting and a part of the tubular extension. The ferrule can have any suitable configuration and can be made of any suitable material. In some embodiments, the at least one ferrule includes a graphite ferrule. Similarly, the compression fitting can have any suitable configuration. In an embodiment, the compression fitting includes a sealing nut configured to be screwed and fastened to the distal fastening end of the sealing section. The sealing nut can include a compression type fitting or connection, such as a Hy-Lok style compression fitting, or a Swagelok type fitting that seals the distal fastening end of the sealing section. Similar to the previous embodiment, the sealing section can also include a fastening formation section configured to interconnect the constriction collar with the cooperative fastening formation section of the connector. Here too, it should be understood that the cooperative fastening formation section includes a thread, mutually engageable ribs and grooves, a rib and slot configuration, a quick lock configuration, or other suitable mutual engagement fastening configurations. In some embodiments, the fastening formation section includes a threaded connection section configured to be cooperatively fastened onto a thread disposed on the connector.

[0039] The constriction collar can have any suitable overall shape and configuration. In an embodiment, the constriction collar has a tubular, preferably substantially cylindrical configuration. Similarly, the constriction collar can be formed from any suitable material. In an embodiment, the constriction collar consists of at least one of aluminum, aluminum alloy, steel, stainless steel, nickel-chromium-iron alloy, brass, or a combination thereof.

[0040] The connector can be formed from any suitable metal or metal alloy on which it is desirable to mount the hydrogen separation membrane. In some embodiments, the connector consists of at least one of steel, stainless steel, nickel-chromium-iron alloy, brass, Inconel, Incoloy, or a combination thereof. Examples of suitable materials include austenitic stainless steel, preferably 300 series stainless steel, such as 303, 304, or 316 stainless steel.

[0041] A metal hydrogen separation membrane includes a metal capable of hydrogen separation through dissociative adsorption of hydrogen on the surface, followed by hydrogen diffusion through a metal lattice driven by a partial pressure drop to the opposite side of the membrane, and then hydrogen separation through recombination of hydrogen atoms and desorption of hydrogen from the permeation side. The metal membrane can produce hydrogen having high permeability and recovery rate when separating H2 / CO2 or other H2-containing gas mixtures. In embodiments, the hydrogen separation membrane includes a Group V (Group 5) - based metal or metal alloy, preferably a metal or metal alloy of vanadium, tantalum, or niobium, more preferably vanadium or a vanadium alloy. In some embodiments, the hydrogen separation membrane can be formed from vanadium or a vanadium alloy. Typically, a particular vanadium metal or alloy is selected based on its suitability for use in a membrane separation device. In some embodiments, the hydrogen separation membrane includes vanadium, aluminum having a content of more than 0 atomic % to 10 atomic %, and Ta having a content of less than 0.01 atomic %, and includes a vanadium alloy having ductility that elongates by more than 10%, preferably more than 11%. The vanadium alloy can further include a grain refinement element selected from Ti, Cr, Fe, Ni, or B having a content of more than 0 atomic % to 5 atomic %, preferably 0.2 atomic % to 4.5 atomic %. In some embodiments, the grain refinement element has a content of 0.1 atomic % to 2 atomic %, preferably 0.1 atomic % to 1 atomic %, more preferably 0.1 atomic % to 1 atomic %. In some embodiments, the hydrogen separation membrane is coated with a Pd-based coating or a Pd-Au-based coating.

[0042] The hydrogen separation membrane can have any suitable configuration. In an exemplary embodiment, the hydrogen separation membrane is tubular. The tubular membrane can have any suitable dimensions as previously described. In some embodiments, the thin tube comprises a tube having an outer diameter of from 2 mm to 25 mm, preferably from 3 mm to 20 mm, and a wall thickness of from 0.05 mm to 1 mm, preferably from 0.1 mm to 1 mm, as described in more detail below. In some embodiments, the hydrogen separation membrane has a wall thickness of from 0.1 mm to 1 mm, preferably from 0.2 mm to 0.8 mm, more preferably from 0.2 mm to 0.5 mm.

[0043] The connector can have any suitable configuration. In many embodiments, the connector comprises a metal fitting, such as a connection fitting or an end cap fitting, preferably a metal fluid connection fitting, more preferably a metal gas connection fitting. In an exemplary embodiment, the connector is tubular. The connector can have any suitable dimensions. In an embodiment, the connector has a wall thickness of from 1 mm to 5 mm, preferably from 1 mm to 3 mm, more preferably from 1 mm to 2 mm.

[0044] The connector forming portion of the connector can have any suitable configuration. In an embodiment, the connector forming portion comprises an inclined or chamfered section configured to receive an end section of the hydrogen separation membrane thereon. In an exemplary embodiment, the connector forming portion comprises an angled inclined end with a reduced diameter of the connector forming portion. This forms an inclined or curved section onto which the hydrogen separation membrane can be mounted. In some embodiments, the inclined or chamfered section includes a frustoconical section. In other embodiments, the connection interface comprises a substantially planar end face of the hydrogen separation membrane disposed in a parallel abutting or adjacent relationship to a substantially planar adjacent face of the connector forming portion.

[0045] The connection between the hydrogen separation membrane and the connector may be any suitable gas-tight connection between their main bodies, such as (but not limited to) a welded connection, a brazed connection, a threaded connection, an O-ring sealed connection, or a similar connection. In some embodiments, the connection includes a welded connection or a brazed connection. In an exemplary embodiment, the connection includes a welded connection. The welded connection can be formed using any suitable welding technique, such as laser welding connection, arc welding connection such as TIG, or electron beam welding. The welded connection preferably includes a continuous weld extending around and covering the connection interface. This forms a continuous weld seal over the connection interface between the hydrogen separation membrane and the connector forming part. In some embodiments, the welding is autogenous (no filler material is added). In other embodiments, a filler material is used in the welded connection, for example, at least one of stainless steel, steel, aluminum silicon, copper, copper alloy, gold-silver alloy, nickel alloy, or silver.

[0046] The connector and the constriction collar are typically different main bodies connected together through a mutually engageable fastening formation / arrangement configuration. However, it should be understood that in some embodiments, the connector may form a fixed or integral part of the constriction collar.

[0047] A second aspect of the present invention provides a method of joining and sealing a hydrogen separation membrane to a metal connector, the method comprising: mounting an end section of the hydrogen separation membrane onto or against a connector forming part of the connector, wherein the connector is formed from a metal different from the hydrogen separation membrane, the hydrogen separation membrane has an outer diameter (D) around a longitudinal axis, and the hydrogen separation membrane and the connector forming part are in contact at a connection interface where the end face of the hydrogen separation membrane is near, substantially abutting, or overlapping an adjacent face of the connector forming part; joining the hydrogen separation membrane to the connector forming part to join and seal the hydrogen separation membrane to the connector over the connection interface; Placing a constricted collar over the hydrogen separation membrane such that it extends at least from the connection interface and axially extends covering the hydrogen separation membrane with respect to the longitudinal axis comprising The constricted collar is an expansion section configured to axially extend covering the hydrogen separation membrane with respect to the longitudinal axis from a constricted end to an expansion diameter, the constricted end being configured to extend around the hydrogen separation membrane at or near the connection interface with respect to the longitudinal axis, having an inner surface defining a constricted diameter (C) configured to extend around the outer surface of the hydrogen separation membrane, the expansion section extending from the constricted end and comprising a transition section with a curved surface having a transition radius of at least 0.1D The expansion section includes a section angled or curved such that the diameter of the constricted collar expands from the constricted diameter C to an expansion diameter including a diameter of at least 1.01D

[0048] In some embodiments, a second aspect of the present invention provides a method of joining and sealing a hydrogen separation membrane to a metal connector, the method comprising mounting an end section of the hydrogen separation membrane onto or against a connector forming portion of the connector, the connector being formed from a metal different from the hydrogen separation membrane, the hydrogen separation membrane having an outer diameter (D) around the longitudinal axis, and the hydrogen separation membrane and the connector forming portion contacting at a connection interface where the end face of the hydrogen separation membrane is near, substantially abutting, or overlapping an adjacent face of the connector forming portion joining the hydrogen separation membrane to the connector forming portion to join and seal the hydrogen separation membrane to the connector over the connection interface Placing a constricted collar over the hydrogen separation membrane such that it extends at least from the connection interface and axially extends covering the hydrogen separation membrane with respect to the longitudinal axis comprising The constricted collar is An expansion section configured to extend axially covering a hydrogen separation membrane with respect to the longitudinal axis from a narrow end to an expansion diameter, wherein the narrow end is configured to extend around the hydrogen separation membrane at or near a connection interface with respect to the longitudinal axis, and having an inner surface defining a narrow diameter (C) configured to extend around the outer surface of the hydrogen separation membrane, comprising the expansion section, The expansion section includes a transition section extending from the narrow end and having a curved surface with a transition radius of at least 0.1D. The expansion section includes an angled or curved section. The diameter of the narrow collar expands from the narrow diameter to the expansion diameter at an average expansion angle with respect to the longitudinal axis from greater than zero degrees to 17.5 degrees. The expansion diameter includes at least 1.01D. The expansion section extends by at least 0.1D with respect to the longitudinal axis.

[0049] In this method, first, the hydrogen separation membrane is joined to a metal (e.g., stainless steel) connector using a suitable joining or connection method, such as a welding method like laser welding, arc welding such as TIG, or electron beam welding. Second, a specially configured narrow collar is disposed near or covering a connection interface configured to extend around the hydrogen separation membrane and restrict membrane expansion near the connection interface / joint during hydrogenation of the hydrogen separation membrane.

[0050] It should be understood that this second aspect of the present invention can include any one or a combination of the features described above with respect to the narrow collar described in the first aspect of the present invention. Similarly, the narrow collar has the features defined in the fifth aspect shown below of the present invention, and its disclosure is to be understood as equally applicable to this second aspect of the present invention. Further, in embodiments, the method according to this second aspect of the present invention can use, and / or can be used to form, the joining and sealing arrangement configuration according to the first aspect of the present invention.

[0051] Here again, the constriction collar includes a constriction section that moves the expansion zone of the hydrogen separation membrane away from the weld joint, thereby reducing the strain applied to the weld joint and enabling the seal to remain intact without being damaged even if there are changes in the expansion and contraction that occur when the membrane hydrogenation changes. In addition, the constriction collar includes an expansion section that enables the hydrogenated hydrogen separation membrane to expand, preferably gradually expand, as the hydrogen separation membrane extends away from the connection portion along the longitudinal axis X-X within the constriction collar towards its natural hydrogenated expansion diameter.

[0052] It has been found that using a constriction collar to protect the connection portion and the seal forms a weld seal that can withstand the volume expansion of the Pd-coated hydrogen separation metal membrane when absorbing hydrogen through the metal lattice during hydrogen diffusion. This occurs as part of the start of membrane operation when the hydrogen partial pressure gradually increases from zero to the final operating conditions. The fluid seal formed by the connection interface seal is also maintained during the subsequent expansion and contraction of the tubular hydrogen separation metal membrane that occurs when the hydrogenation changes, i.e., during the membrane cycling operation (when changing the operating hydrogen partial pressure and temperature) and during the desorption of hydrogen from the membrane before shutdown.

[0053] Here again, the connector can include various sections that extend over the connection interface and also over the connector. In some embodiments, the connector includes a tubular extension that extends longitudinally away from the connection interface, and the constriction collar includes a sealing section configured to extend over the tubular extension of the connector to a distal fastening end. In these embodiments, the method further includes fastening a compression fitting to the distal fastening end of the sealing section, the compression fitting including at least one ferrule that seals around a section of the tubular extension of the connector when the compression fitting is fastened to the distal fastening end of the sealing section.

[0054] As described for the first aspect of the present invention, the ferrule includes a sealing member that is compressed by a compression joint to form a fluid seal between the compression joint and a portion of the tubular extension. The ferrule can have any suitable configuration and can be made from any suitable material. In some embodiments, at least one ferrule includes a graphite ferrule. Similarly, the compression joint can have any suitable configuration. In an embodiment, the compression joint includes a sealing nut configured to be screwed and fastened to the distal fastening end of the sealing section. The sealing nut can include a compression type joint or connection, such as a Hy-Lok style compression joint or a Swagelok type joint that seals the distal fastening end of the sealing section. Similar to the previous embodiments, the sealing section can include a fastening formation section configured to interconnect the constriction collar with the cooperative fastening formation section of the connector. Here too, it should be understood that the cooperative fastening formation section includes a thread, mutually engageable ribs and grooves, a rib and slot configuration, a quick lock configuration, or other suitable mutual engagement fastening configuration. In some embodiments, the fastening formation section includes a threaded connection section configured to be cooperatively fastened onto a thread disposed on the connector.

[0055] The connector and the hydrogen separation membrane can have the features defined above for the first aspect of the present invention. The connector can be formed from at least one of any suitable metal, such as steel, stainless steel, nickel-chromium-iron alloy, brass, inconel, inconloy, or combinations thereof.

[0056] Similarly, the hydrogen separation membrane can include any suitable hydrogen separation metal or alloy. In embodiments, the hydrogen separation membrane includes a Group V-based metal or metal alloy, preferably a metal or metal alloy of vanadium, tantalum, or niobium, more preferably vanadium or a vanadium alloy. In some embodiments, the hydrogen separation membrane includes vanadium or a vanadium alloy, for example, vanadium, aluminum having a content of more than 0 atom % to 10 atom %, and Ta having a content of less than 0.01 atom %, and can be formed from a vanadium alloy having ductility that elongates by more than 10%, preferably more than 11%. In some embodiments, the vanadium alloy further includes a grain refinement element selected from Ti, Cr, Fe, Ni, or B having a content of more than 0 atom % to 5 atom %, preferably 0.2 atom % to 4.5 atom %. The hydrogen separation membrane can also be coated in a Pd-based coating or a Pd-Au-based coating. In many embodiments, the hydrogen separation membrane is tubular. Similarly, in many embodiments, the connector is tubular. The connector forming portion can have any suitable configuration. In embodiments, the connector forming portion includes an inclined or chamfered section configured to receive an end section of the hydrogen separation membrane thereon.

[0057] The connection between the hydrogen separation membrane and the connector may be any suitable gas-tight connection between their body parts, such as (but not limited to) a welded connection, a brazed connection, a threaded connection, an O-ring sealed connection, or a similar connection. In some embodiments, the connection includes a welded connection or a brazed connection. In an exemplary embodiment, the connection includes a welded connection. The welded connection may be formed using any suitable welding technique, such as laser welding, arc welding such as TIG, or electron beam welding. The welded connection preferably includes a continuous weld extending around and covering the connection interface. This forms a continuous weld seal over the connection interface between the hydrogen separation membrane and the connector forming part. In some embodiments, the welding is autogenous (no filler wire is added). In other embodiments, at least one of a filler material, such as aluminum silicon, copper, copper alloy, gold-silver alloy, nickel alloy, or silver, is used for the welded connection.

[0058] As previously described, the connector and the constriction collar are typically different body parts that are connected together through mutually engageable fastening formations / arrangements. However, it should be understood that in some embodiments, the connector may form a fixed or integral part of the constriction collar.

[0059] A third aspect of the present invention also relates to a gas separation membrane system incorporating a hydrogen separation membrane joined and sealed to a connector forming part using the joining and sealing arrangement according to the first aspect of the present invention and / or prepared by the method according to the second aspect of the present invention.

[0060] The use of the sealing and joining arrangement of the present invention enables a hydrogen separation tubular membrane to be fitted into a catalytic membrane reactor (CMR) or a membrane separator for use in the selective separation of hydrogen gas from a mixed gas stream (including hydrogen and other gases), and to produce high-purity hydrogen (suitable for fueling FCEVs) in the permeate flow from the membrane. The collar and related methods provide a means of joining a hydrogen separation membrane to other metal structures (such as tube connections, tube ends, etc.) to form a hydrogen separation system while maintaining seal integrity, i.e., while maintaining mechanical integrity / robustness through multiple cycles of operation.

[0061] A fourth aspect of the present invention provides at least one catalytic membrane reactor (CMR) or membrane separator comprising at least one hydrogen separation membrane joined and sealed to a connector using the joining and sealing arrangement according to the first aspect of the present invention and / or prepared by the method according to the second aspect of the present invention.

[0062] The membranes of the present invention can have any suitable configuration selected based on the particular advantages that the configuration can bring to a particular CMR or separator configuration.

[0063] A CMR is essentially a two-dimensional device that guides synthesis gas or alternatively ammonia (when catalytically decomposing ammonia) one-dimensionally along a catalytic bed adjacent to the membrane. Flat membranes are easier and cheaper to produce than tubular membranes, but since the membrane is sealed around its outer edge, it has a larger seal area. This sealing configuration results in a large seal area and thus can be prone to leakage between the raffinate and the permeate gas stream. Tubular membranes enable the use of tubular CMRs and thus can reduce the seal area. In a tubular reactor, seals are only required at each end of the tube. The joining and sealing methods of the present invention can be used to provide these seals. Similar considerations apply to membrane separator configurations.

[0064] In some embodiments, the hydrogen separation membrane of the present invention has a tubular configuration, preferably including a tube. The tubular membrane can have any suitable dimensions as described above. In some embodiments, the thin-walled tube comprises a tube having an outer diameter of from 2 mm to 25 mm, preferably from 3 mm to 20 mm, and a wall thickness of from 0.05 mm to 1 mm, preferably from 0.1 mm to 10 mm. In an exemplary body portion, the tubular membrane comprises a thin-walled tube comprising a vanadium alloy containing vanadium, aluminum having a content of more than 0 atomic % to 10 atomic %, and Ta having a content of less than 0.01 atomic %, and having a ductility that elongates by more than 10%, preferably more than 11%. In some embodiments, the hydrogen separation membrane is coated with a Pd-based coating or a Pd-Au-based coating.

[0065] It should be understood that the alloy components and mechanical properties of the hydrogen separation membrane according to the fourth aspect of the present invention are the same as those described above for the first and second aspects of the present invention, and it should be understood that they are similarly applicable to this aspect of the present invention.

[0066] A fifth aspect of the present invention provides a hydrogen separation membrane constriction collar configured to extend over the hydrogen separation membrane, the constriction collar being configured to extend over the hydrogen separation membrane from a connection interface between the hydrogen separation membrane and a connector, the constriction collar having a longitudinal axis, an expansion section configured to extend axially over the hydrogen separation membrane with respect to the longitudinal axis from a constricted end to an expanded diameter, the constricted end defining a constricted diameter (C) configured to extend around the hydrogen separation membrane at or near the connection interface with respect to the longitudinal axis, the expansion section having an inner surface extending around an outer surface of the hydrogen separation membrane and including, the expansion section includes a transition section extending from the constricted end and having a curved surface with a transition radius of at least 0.1C, The expansion section expands from the constricted diameter to the expanded diameter at an average expansion angle with respect to the longitudinal axis that includes a non-zero angle of less than 17.5 degrees of the constriction collar diameter, and the expanded diameter includes an angled or curved section that includes at least 1.01C.

[0067] Similar to the first aspect, the inventors have found that the connection between the metal hydrogen separation membrane and the connector is itself prone to problems (resulting in leakage) and may not have the desired robustness against changes in membrane hydrogenation. The constriction collar of this fifth aspect of the present invention is designed to restrict the volumetric expansion of the metal hydrogen separation (hydrogen selectivity) tubular membrane at and near the connection joint between the hydrogen separation membrane and the connector when exposed to hydrogen. The constriction collar allows the hydrogenated hydrogen separation membrane to expand from the constricted diameter at the constricted end of its expansion section to its natural hydrogenated expanded diameter as the hydrogen separation membrane extends away from the connection between the hydrogen separation membrane and the connector along the longitudinal axis within the constriction collar, preferably transitioning to a larger expanded diameter that allows it to expand gradually / progressively.

[0068] It should be understood that the constriction collar of the joint and seal arrangement configuration of the first aspect of the present invention shares many features similar to the constriction collar described for this fifth aspect of the present invention, and the following disclosure of the constriction collar of the fifth aspect of the present invention is equally applicable to similar features of the constriction collar with the features of the joint and seal arrangement configuration of the first aspect of the present invention, and vice versa.

[0069] In many embodiments, the constricted end of the constriction collar comprises a constricted section configured to move the expansion zone of the hydrogen separation membrane away from the connection interface / junction, thereby reducing the strain on the welded joint. In these embodiments, the constricted section is configured to extend axially covering the hydrogen separation membrane from the connection end with respect to the longitudinal axis towards the expansion section, and the constricted section has an inner surface extending around the longitudinal axis with a constricted diameter. The transition section extends from a transition region, area, point, or the like between the constricted section and the expansion section. Here, the transition section extends from a transition region, area, or point where the constricted section contacts the expansion section.

[0070] It should be understood that the transition section includes a curved surface forming a transition surface between the constricted end / constricted section and the expansion section of the collar. The curved surface has a curvature following a radial curvature of at least 0.1C. This curvature typically includes only a short segment or portion of its radial curvature, and it should be understood that the curvature joins the ends between the constricted end / constricted section and the angled or curved section of the expansion section to form the transition surface.

[0071] Also, the outer diameter D should be understood to be the outer diameter of the hydrogen separation membrane when the hydrogen separation membrane is in an unhydrogenated state (i.e., not in a hydrogenated expanded state). Since the outer diameter depends on the size of the membrane used for hydrogen separation, it can have any suitable dimension.

[0072] The narrow diameter C is preferably sized between 0.95D and 1.05D. In embodiments, the narrow diameter includes diameters from 0.97D to 1.05D, preferably from 0.99D to 1.05D, and more preferably from 1D to 1.05D. In some embodiments, the narrow diameter includes diameters from 0.98D to 1.05D, preferably from 0.999D to 1.05D. In some embodiments, the narrow diameter includes diameters from 1D to 1.04D, preferably from 1D to 1.02D, and more preferably from 1.005D to 1.01D.

[0073] The length of the narrow section of the narrowing collar is preferably selected to provide a sufficient spacing of the connection interface from the expansion section, thereby reducing movement and other force transfer from the expansion and contraction changes experienced when a change in membrane hydrogenation occurs. In embodiments, the narrow section is configured to extend over the hydrogen separation membrane from the connection interface to the transition section for at least 0.25C. In some embodiments, the narrow section is configured to extend over the hydrogen separation membrane from the connection interface to the transition section from 0.25C to 2C, preferably from 0.25C to 1.5C, more preferably from 0.25C to 1C.

[0074] The expansion diameter D2 is selected to be greater than the outer diameter D of the metal hydrogen separation membrane when the metal hydrogen separation membrane is in the unhydrogenated state and also greater than the narrow diameter C. In embodiments, the expansion diameter D2 is at least 1.01C, preferably at least 1.02C. In some embodiments, the expansion diameter D2 is the maximum diameter of the hydrogen separation membrane after hydrogenation, diameter D MHare selected to be larger. Hydrogen separation (hydrogen-selective) membrane tubes, such as vanadium-based hydrogen separation membranes, can expand by at least +10% in volume, and more typically by about +13%, compared to ambient conditions without hydrogen, when hydrogenated at conventional operating temperatures / pressures, and the linear expansion in one direction / axis can be up to 5%, for example up to the diameter. In an embodiment, the expanded diameter D2 is thus at least 1.05D to accommodate the linear expansion upon hydrogenation of the hydrogen separation membrane. In an embodiment, the expanded diameter D2 is at least 1.07C, preferably at least 1.08C, more preferably at least 1.1C. In some embodiments, the expanded diameter D2 is at least 1.12C, preferably at least 1.2C.

[0075] Again, the maximum diameter of the hydrogen separation membrane after hydrogenation, diameter D MH is greater than the constriction diameter C of the constriction section of the constriction collar. Similarly, the maximum diameter of the hydrogen separation membrane after hydrogenation, diameter D MH is greater than the outer diameter D of the metal hydrogen separation membrane when the metal hydrogen separation membrane is in the unhydrogenated state -- which can be understood from the nature of the hydrogenation process itself.

[0076] As described for the first aspect, the expansion section can generally comprise a linear, curved, or other shaped or undulating surface that expands from the constriction diameter to the expansion diameter. The shape can have non-uniform or irregular shapes or undulations. However, the shape is generally preferably a regular and / or smooth shape, for example, with a linear expansion angle or a smooth curve. If the expansion section includes a curve, the curve can include a continuous curve including a transition section. In some embodiments, the transition section can follow the same or a similar curve as the entire surface of the expansion section and share a common radius. Here, the angled or curved section of the transition section and the expansion section following the transition section can have the same or a similar curve and share a common radius.

[0077] The change from the constricted diameter to the expanded diameter within the expansion section can have any suitable shape. In some embodiments, the expansion section comprises an inclined or curved surface from the transition section to the expanded diameter. In an embodiment, the expansion section comprises an inclined or tapered surface. For example, the diameter of the constriction collar can be configured to expand at an average expansion angle with respect to the longitudinal axis that includes an angle of less than 17.5 degrees (i.e., an angle from greater than zero degrees to 17.5 degrees), preferably from 0.5 degrees to 6 degrees, more preferably from 3 degrees to 5 degrees, from the constricted diameter to the expanded diameter within the expansion section. In some embodiments, the diameter of the constriction collar can be configured to expand at an average expansion angle with respect to the longitudinal axis that includes an angle of less than 15 degrees, preferably an angle of less than 10 degrees (i.e., an angle from greater than zero degrees to 10 degrees), preferably from 1 degree to 10 degrees, more preferably from 3 degrees to 6 degrees, even more preferably from 4 degrees to 5 degrees, from the constricted diameter to the expanded diameter within the expansion section. In some embodiments, the diameter of the constriction collar can be configured to expand at an average expansion angle with respect to the longitudinal axis that includes at least 1 degree, typically from 1 degree to 17.5 degrees, preferably from 1 degree to 15 degrees, more preferably from 2 degrees to 7 degrees, from the constricted diameter to the expanded diameter within the expansion section.

[0078] It should be understood that the average expansion angle includes the average growth / expansion rate or average growth / expansion rate of the expansion section with respect to the longitudinal axis. In embodiments where the expansion section has a linear slope, this substantially corresponds to the angle formed by that linear slope. In other embodiments where the expansion section is curved or of another non-linear shape, the average expansion angle is the average angle or mean angle formed by the surface within that expansion section. For example, in a curved surface, the average expansion angle is the average angle of that curvature.

[0079] In embodiments, the average inflation angle is a non-zero angle less than 17.5 degrees (i.e., an angle from greater than zero degrees to 17.5 degrees), preferably from 0.5 degrees to 6 degrees, more preferably from 3 degrees to 5 degrees. In some embodiments, the average inflation angle is a non-zero angle less than 15 degrees, preferably a non-zero angle less than 10 degrees (i.e., an angle from greater than zero degrees to 10 degrees), preferably from 1 degree to 10 degrees, more preferably from 3 degrees to 6 degrees, even more preferably from 4 degrees to 5 degrees. In some embodiments, the average inflation angle is from 1 degree to 17.5 degrees, preferably from 1 degree to 15 degrees, more preferably from 1 degree to 12 degrees, even more preferably from 2 degrees to 10 degrees, even more preferably from 2 degrees to 7 degrees. In some embodiments, the average inflation angle is from 3 degrees to 10 degrees, preferably from 3 degrees to 7 degrees. In some embodiments, the inflation angle is at least 1 degree, more preferably at least 2 degrees, even more preferably at least 3 degrees, even more preferably at least 5 degrees. In some embodiments, the average inflation angle is about 5 degrees. Then, the length of the inflation section is determined by the inflation angle and the size of the inflation diameter that the tapered portion must reach. However, the inflation section extends at least 0.1D with respect to the longitudinal axis.

[0080] Another way to represent the inflation rate of the inflation section is as the radial inflation rate of the inner diameter of the collar from the stenotic end to the inflation diameter of the collar. In some embodiments, the maximum radial inflation rate is less than 0.315 mm / mm, preferably from 0.0087 mm / mm to 0.105 mm / mm, more preferably from 0.052 mm / mm to 0.087 mm / mm. In some embodiments, the maximum radial inflation rate is less than 0.27 mm / mm, preferably less than 0.176 mm / mm.

[0081] The expansion section is a section in which the expansion of the hydrogen separation membrane can preferably expand gradually up to the maximum expansion diameter over the length of the hydrogen separation membrane (with respect to the longitudinal axis). As a result of rapid expansion, stress rising regions can still occur within the hydrogen separation membrane. Therefore, the expansion section preferably extends at least 0.2C with respect to the longitudinal axis. The longer the length, the more advantageous it can be. Thus, in an embodiment, the expansion section extends at least 0.3C, preferably at least 0.4C, more preferably at least 0.5C with respect to the longitudinal axis.

[0082] Also, it should be understood that the transition section is disposed at the transition to a tapered or curved section (i.e., a tapered or curved surface) angled from the constricted diameter to the expansion section. In an embodiment, the average expansion angle includes the curvature (including the transition radius) provided by the transition section.

[0083] As detailed above, when hydrogen is introduced into the hydrogen separation membrane, the hydrogenated hydrogen separation membrane (tube) expands within the constriction collar, and this expansion is restricted by the limits of the inner surface of the constriction collar. In the constriction section, the outer surface of the hydrogen separation membrane abuts and engages against the inner wall of that section. Similarly, the outer surface of the hydrogen separation membrane abuts and engages against the inner wall of the expansion section until it reaches a point where it reaches the natural hydrogen expansion diameter of the hydrogen separation membrane. In the transition section, the outer surface of the hydrogenated hydrogen separation membrane has a complementary shape / curvature at the transition from the constriction diameter to the angled or curved section of the expansion section (i.e., the tapered or curved surface). Here, the membrane expands from the constriction diameter to the angled or curved section of the collar in accordance with the shape of the transition section. The transition section thus provides a curved surface configured to prevent stress concentration points from forming when the inner surface of the constriction collar transitions to the angled or curved section of the expansion section (i.e., the tapered or curved surface). The curved surface of the transition section preferably has a radius of curvature of at least 0.1C. In embodiments, the transition radius includes from 0.1C to 10C, preferably from 0.5C to 5C, more preferably from 1C to 5C. In some embodiments, the transition radius includes from 0.5C to 10C, more preferably from 1C to 10C, more preferably from 2C to 10C.

[0084] The constriction collar is designed to extend from and preferably cover the connection interface of the hydrogen separation membrane. In embodiments, the constriction section of the constriction collar is configured to extend over the connection interface. In embodiments, the constriction collar can also be configured to extend over the connection interface and at least a portion of the connector.

[0085] In an embodiment, the constriction collar includes a collar fastening section configured to fasten onto a section of the connector. The constriction collar is preferably configured to cover the connection interface and extend to the constriction collar fastening section. Typically, the constriction collar extends from the constricted end to cover the connection interface and extend to the constriction collar fastening section. The constriction collar section is configured to fasten onto a section of the connector and includes a fastening formation section configured to interconnect the constriction collar to the cooperative fastening formation section of the connector. It should be understood that the cooperative fastening formation section may include threads, mutually engagable ribs and grooves, rib and slot configurations, quick-lock configurations, or other suitable mutual engagement fastening configurations. In some embodiments, the fastening formation section includes a threaded connection section configured to cooperatively fasten onto threads disposed on the connector.

[0086] In an embodiment, the constriction collar further includes an end cap configured to form an end seal around the connector. The end cap preferably includes a sealing cap configured to seal one end of the hydrogen separation membrane when the connector is fastened. In some embodiments, the end cap extends from the connection interface, preferably covering the connection interface, around the end of the connector distal to the connection interface. Typically, the end cap extends from the constricted section, covering the connection interface, around the end of the connector distal to the connection interface. The end cap preferably includes a fastening formation section configured to interconnect the constriction collar to the cooperative fastening formation section of the connector. It should be understood that the cooperative fastening formation section may include threads, mutually engagable ribs and grooves, rib and slot configurations, quick-lock configurations, or other suitable mutual engagement fastening configurations. In some embodiments, the fastening formation section includes a threaded connection section configured to cooperatively fasten onto threads disposed on the connector.

[0087] In an embodiment, the connector includes a tubular extension that extends longitudinally away from the connection interface with respect to the longitudinal axis. Here, the constriction collar includes a sealing section configured to extend over the connector, preferably over its tubular extension, up to the distal fastening end. Typically, the sealing section extends from the constriction section to cover the connection interface up to the distal fastening end. The constriction collar in this embodiment further includes a compression fitting configured to fasten to the distal fastening end of the sealing section, and at least one ferrule configured to seal around one section of the connector, preferably one section of its tubular extension, when the compression fitting is fastened to the distal fastening end of the sealing section. The ferrule includes a sealing member that is compressed by the compression fitting to form a fluid seal between the compression fitting and a portion of the tubular extension. The ferrule can have any suitable configuration and can be made of any suitable material. In some embodiments, the at least one ferrule includes a graphite ferrule. Similarly, the compression fitting can have any suitable configuration. In an embodiment, the compression fitting includes a sealing nut configured to threadedly engage and fasten to the distal fastening end of the sealing section. The sealing nut can include a compression type fitting or connection, such as a Hy-Lok style compression fitting, or a Swagelok type fitting that seals the distal fastening end of the sealing section. Similar to the previous embodiment, the sealing section can also include a fastening formation section configured to interconnect the constriction collar with the cooperative fastening formation section of the connector. Here too, it should be understood that the cooperative fastening formation section can include a thread, inter-engaging ribs and grooves, rib and slot configurations, quick-lock configurations, or other suitable inter-engaging fastening configurations. In some embodiments, the fastening formation section includes a threaded connection section configured to cooperatively fasten onto a thread disposed on the connector.

[0088] The constriction collar can have any suitable overall shape and configuration. In embodiments, the constriction collar comprises a tubular, preferably substantially cylindrical configuration. Similarly, the constriction collar can be formed from any suitable material. In embodiments, the constriction collar consists of at least one of aluminum, aluminum alloy, steel, stainless steel, nickel-chromium-iron alloy, brass, or combinations thereof.

[0089] A sixth aspect of the present invention provides a hydrogen separation membrane constriction collar when used on a joint between a hydrogen separation membrane and a metal connector, the constriction collar being configured to extend over the hydrogen separation membrane from a connection interface between the hydrogen separation membrane and the connector, the constriction collar having a longitudinal axis, an expansion section configured to axially extend over the hydrogen separation membrane with respect to the longitudinal axis from a constricted end to an expanded diameter, the constricted end being configured to extend around the hydrogen separation membrane at or near the connection interface with respect to the longitudinal axis, the expansion section having an inner surface that defines a constricted diameter (C) configured to extend around the outer surface of the hydrogen separation membrane, comprising the expansion section includes a transition section extending from the constricted end and having a curved surface with a transition radius of at least 0.1C, the expansion section includes an angled or curved section extending from a transition section where the diameter of the constriction collar expands from the constricted diameter to an expanded diameter including a diameter of at least 1.01C.

[0090] It should be understood that the constriction collars in the first and fifth aspects of the present invention share many features similar to the constriction collar of this sixth aspect of the present invention, and the above disclosure of the first and fifth aspects of the present invention is equally applicable to the similar features of the constriction collar of this sixth aspect of the present invention.

[0091] A seventh aspect of the present invention provides a method of joining and sealing a hydrogen separation membrane to a metal connector, the method comprising A step of mounting an end section of a metal hydrogen separation membrane on or against a connector forming portion of a connector, wherein the connector is formed of a metal different from the hydrogen separation membrane, the hydrogen separation membrane has an outer diameter (D) around a longitudinal axis, and the hydrogen separation membrane and the connector forming portion are in contact at a connection interface where the end face of the hydrogen separation membrane is near, substantially in contact with, or overlapping the adjacent face of the connector forming portion, A step of joining the hydrogen separation membrane to the connector forming portion, joining the hydrogen separation membrane to the connector on the connection interface, and sealing, A step of disposing a constriction collar according to the fifth or sixth aspect of the present invention on the hydrogen separation membrane so as to extend at least from the connection interface and axially extend covering the hydrogen separation membrane with respect to the longitudinal axis Including.

[0092] It should be understood that this seventh aspect of the present invention can include any one or a combination of the features described above with respect to the constriction collar including the fifth and sixth aspects of the present invention. It should also be understood that this seventh aspect of the present invention can include any one or a combination of the features described above with respect to the method including the second aspect of the present invention. Further, in an embodiment, the method according to this seventh aspect of the present invention can be used to form the joining and sealing arrangement according to the first aspect of the present invention.

[0093] The eighth aspect of the present invention provides a joining and sealing arrangement for joining and sealing a hydrogen separation membrane to a metal connector, the sealing arrangement comprising: A metal hydrogen separation membrane mounted on or against the connector around a longitudinal axis, wherein the connector is formed of a metal different from the hydrogen separation membrane, the hydrogen separation membrane has an outer diameter (D) around the longitudinal axis, and the hydrogen separation membrane and the connector forming portion are in contact at a connection interface where the end face of the hydrogen separation membrane is near, substantially in contact with, or overlapping the adjacent face of the connector forming portion, A connection portion connecting the hydrogen separation membrane and the connector forming portion around the connection interface, A constriction collar according to a fifth or sixth aspect of the invention, at least extending from a connection interface and configured to extend axially covering a hydrogen separation membrane with respect to a longitudinal axis, and comprises.

[0094] It should be understood that this eighth aspect of the invention can include any one or a combination of the features described above with respect to the constriction collar including the fifth or sixth aspect of the invention. It should also be understood that this eighth aspect of the invention can include any one or a combination of the features described above with respect to the joining and sealing arrangement according to the first aspect of the invention.

[0095] Next, the invention will be described with reference to the figures of the accompanying drawings, which illustrate specific preferred embodiments of the invention.

Brief Description of the Drawings

[0096]

Figure 1

Figure 2

Figure 2A

Figure 3

Figure 3A

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Figure 12

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Figure 17

DETAILED DESCRIPTION OF THE INVENTION

[0097] The present invention relates to an arrangement for joining and sealing a metal hydrogen separation membrane to a connector formed from a different metal, such as stainless steel, including the connection portion between the hydrogen separation membrane and the connector.

[0098] As described above, the present invention relates to a metal membrane that can be used to produce hydrogen having high permeability and recovery rate when separating H2 / CO2 or other H2-containing gas mixtures. In an embodiment, the hydrogen separation membrane includes a Group 5 (Group V) - based metal or metal alloy such as a metal or metal alloy of vanadium, tantalum, or niobium. For the purposes of the remainder of this specification, a hydrogen separation membrane formed from vanadium or a vanadium alloy is exemplified. However, it should be understood that the present invention can be more generally applied to other metal hydrogen separation membranes, and in particular to other Group 5 metals or metal alloys.

[0099] As described in the background art, vanadium-based hydrogen-selective membrane tubes can have a linear (dimensional) expansion of up to about +5% and a volume expansion of up to about +15% when hydrogenated at conventional operating temperatures / pressures compared to ambient conditions without hydrogen. Other metal hydrogen-selective membrane tubes, such as those formed from Group 5 metals and their alloys, also have similar linear and volume expansions when hydrogenated. This expansion can apply significant strain and stress on the welded connection between the vanadium-based membrane and the connector, and the significant strain and stress can be large enough to significantly affect the integrity of the seals and joints around the sealed welded connection. The inventors have found that a constriction collar can be advantageously used to mechanically limit the hydrogenated expansion of the vanadium-based membrane at and near the welded connection. When hydrogen is introduced into the vanadium-based membrane, the hydrogenated vanadium-based membrane (tube) expands within the constriction collar, and the expansion is constrained by the limits of the inner surface of the constriction collar.

[0100] FIG. 1 illustrates a first embodiment of the joining and sealing arrangement 100 of the present invention. The arrangement 100 includes the following. (1) A vanadium-based membrane 110, preferably a vanadium or vanadium alloy tube suitable for use as a hydrogen-selective membrane, as taught in, for example, U.S. Patent No. 10,590,516, the contents of which are hereby incorporated by reference. The vanadium-based membrane 110 has an outer diameter (D) around the longitudinal axis X-X. As described above, the outer diameter D is the outer diameter of the vanadium-based membrane when the vanadium-based membrane 110 is in an unhydrogenated state (i.e., not in a hydrogenated expanded state). The vanadium-based membrane 110 preferably includes a thin-walled tube having an outer diameter of from 2 mm to 25 mm and a wall thickness of from 0.1 mm to 1 mm. However, it should be understood that other configurations may be used as well, as described above. Similarly, it should be understood that other metal membranes, such as other Group 5 metals like tantalum or niobium metals or metal alloys, may be used. (2) A connector 120 including a metal fluid connection joint (preferably a metal gas connection joint) formed from one of a metal or metal alloy different from the vanadium-based film 110, typically steel, stainless steel, nickel-chromium-iron alloy, brass, Inconel, Incoloy, or a combination thereof. The connector 120 includes a connector forming portion 122 configured to receive the end section 111 of the vanadium-based film 110. In the illustrated embodiment, the connector forming portion 122 includes an inclined section in the form of a frustum-shaped section. However, it should be understood that other configurations are possible. (3) A welding connection portion 130 covering the connection interface 132 between the end section 111 of the vanadium-based film 110 and the end section 111 of the vanadium-based film 110 and the connector forming portion 122 where the end section 111 of the vanadium-based film 110 substantially abuts or overlaps the adjacent surface of the connector forming portion 122. The welding connection portion 130 includes a continuous weld extending around the connection interface and covering the connection interface 132. The welding connection portion 130 can be formed using any suitable welding technique, such as laser welding connection, or arc welding connection such as TIG, or electron beam welding. As will be shown in more detail below, it should be understood that other types of connections, such as threaded connection portions or O-ring sealing connection portions, can be used as well. (4) A constriction collar 140 extending at least from the connection interface 132 and the welding connection portion 130 and configured to extend axially covering the vanadium-based film 110 with respect to the longitudinal axis X-X. In the illustrated embodiment, the constriction collar extends covering the connection interface 132 and the welding connection portion 130 and axially covers at least a portion of the vanadium-based film 110 and the connector 120 with respect to the longitudinal axis X-X. The illustrated constriction collar 140 includes a tube having a substantially cylindrical shape. However, it should be understood that the constriction collar can have any suitable overall shape and configuration. The constriction collar typically consists of at least one of steel, stainless steel, nickel-chromium-iron alloy, brass, or a combination thereof.

[0101] As illustrated in FIGS. 1, 2, and 3, the constriction collar 140 has the following interconnected sections: (1) a constriction section 144, (2) an expansion section 146, and (3) a transition section 148 at the beginning of the expansion section 146. The illustrated constriction collar 140 also includes a collar fastening section 149. Each of these sections will be described in further detail below.

[0102] The narrow section 144 moves the expansion zone of the vanadium-based membrane 110 away from the weld joint 130, thereby reducing the strain applied to the weld joint 130 and enabling the weld connection 130 to remain intact without being damaged even if there are changes in the expansion and contraction that occur when the membrane 110 is hydrogenated. This is done by imposing mechanical constraints on the hydrogen-metal (H / M) expansion within this section. As best shown in FIG. 1, the narrow section 144 is configured to extend axially from the connection interface 132 (and the weld connection 130 thereon) covering the vanadium-based membrane 110 to the transition section 148, which is located at the beginning of the expansion section 146. Here, the inner surface 150 of the narrow collar 140 abuts, and more preferably is spaced apart from (e.g., substantially parallelly spaced apart from), the outer surface 152 of the vanadium-based membrane 110. The inner surface of the narrow section 144 defines a narrow diameter C that is 0.95 times to 1.05 times the outer diameter D of the vanadium-based membrane 110. In embodiments such as the illustrated embodiment, the narrow diameter C is greater than D (C > D). For example, C can be from 1.01D to 1.05D, such as a value 0.05 mm greater than the outer diameter D of the vanadium-based membrane 110. Here, the narrow diameter C of the inner surface 150 of the narrow section 144 is spaced apart from the outer surface 152 of the vanadium-based membrane 110 when the vanadium-based membrane is in the unhydrogenated state. This spacing results in a small gap that allows the vanadium-based membrane and the connector to fit within the narrow collar. It is also preferable that the narrow diameter is not more than 0.12 mm greater than the outer diameter D of the vanadium-based membrane 110 so as to substantially limit the movement of the vanadium-based membrane 110 around the weld connection 130 between the vanadium-based membrane 110 and the connector 120 when there are changes in the expansion and contraction that occur when the membrane is hydrogenated. The narrow diameter C in the narrow section can be substantially the same as D in some embodiments, whereby it should be understood that the overlapping portion of the narrow section 144 of the narrow collar 140 and the vanadium-based membrane 110 are interference-fitted.

[0103] The inner surface 150 of the narrow collar 140 is also preferably spaced from the outer surface 152 of the connector 120, which is on the opposite side of the welded connection, typically substantially parallelly spaced, and the collar also extends to cover the welded connection 130 and the connection interface 132 therein. The narrowing portion 143 of the narrow collar 140 can thus mechanically restrict any expansion of the welded connection during hydrogenation expansion and cyclic operation.

[0104] The dimensions described below are stated with respect to the outer diameter D of the vanadium-based film 110, but it should be understood that these dimensions can equally be expressed with respect to the narrow diameter C. As described above, in some embodiments, the inner surface of the narrow section defines a narrow diameter C that is 0.95 to 1.05 times the outer diameter D of the vanadium-based film 110.

[0105] The length L1 of the narrow section 144 is selected to provide sufficient spacing from the expansion section 146 to the connection interface 132 (and the welded connection 130 thereon). In the embodiment illustrated in FIG. 1, the narrow section 144 extends on the vanadium-based film 110 from the connection interface 132 to the transition section 148 by at least 0.25D, preferably from 0.25D to 2D.

[0106] The expansion section 146 controls the expansion of the vanadium-based membrane 110 that has been hydrogenated using a slope or a curved section, and gradually expands the vanadium-based membrane 110 to its natural diameter as the vanadium-based membrane 110 extends away from the welded connection along the longitudinal axis X-X. The diameter of the constriction collar 100 expands from the constriction diameter C to the expansion diameter D2 within the expansion section 146. This gradual expansion is controlled by the configuration of the expansion section 146, which, in the illustrated embodiment, has a tapered or conical inner diameter 154 from the constriction diameter C to the expansion diameter D2 that gradually increases in diameter at the distal end 147 of the expansion section 146 as shown in FIGS. 1 to 3. In the illustrated embodiment, the change from the constriction diameter C to the expansion diameter D2 includes a transition section 148 (described in more detail below) and an angled section 145 that includes a sloped surface having an expansion angle α with respect to the longitudinal axis that includes a non-zero angle of less than 17.5 degrees (i.e., greater than zero degrees to 17.5 degrees, such as from 0.5 degrees to 17.5 degrees, preferably from 0.5 degrees to 6 degrees). In the illustrated embodiment, the sloped surface is approximately 5 degrees. The expansion diameter D2 is selected to be greater than the maximum diameter of the vanadium-based membrane after hydrogenation. As previously explained, the vanadium-based hydrogen-selective membrane tube can have a linear thermal expansion of up to 5% in one dimension / axis (such as diameter) when hydrogenated at conventional operating temperatures / pressures compared to ambient conditions without hydrogen. The expansion diameter D2 is therefore at least 1.01D, preferably at least 1.02D. However, if the expansion is intended to be greater than the maximum thermal expansion, the expansion diameter D2 can be at least 1.05D. The length L2 of the expansion section is then determined by the expansion angle α and the size of the expansion diameter D2 that the slope / taper section must reach.

[0107] As previously mentioned, it should also be understood that the expansion diameter D2 (FIG. 1) is also greater than the constriction diameter C of the constriction section 144 of the constriction collar 140. Similarly, the maximum diameter of the hydrogen separation membrane 110 after hydrogenation, diameter D MH(Not shown) is larger than the constriction diameter C of the constriction section 144 of the constriction collar 140 and also larger than the outer diameter D of the metal hydrogen separation membrane 110 when the metal hydrogen separation membrane 110 is in the unhydrogenated state -- this can be understood from the nature of the hydrogenation process itself.

[0108] The transition section 148 is disposed at the beginning of the expansion section 146 and forms a curved transition surface between the constriction section 144 and the angled section 145 of the expansion section 146. As illustrated, the transition section 148 comprises a curved surface 119 having a radius R in the range of at least 0.1D, typically from 0.1D to 10D. The transition section 148 thus provides a curved surface configured to prevent the formation of stress concentration points when the inner surface of the constriction collar 140 transitions from the constriction diameter C to the tapered surface of the expansion section. In this regard, when hydrogen is introduced into the vanadium-based membrane, the hydrogenated vanadium-based membrane (tube) expands within the constriction collar 140, and its expansion is restricted by the limits of the inner surface of the constriction collar 140. In the constriction section 144, the outer surface 152 of the vanadium-based membrane 110 abuts and engages the inner surface 150 of that section. Similarly, the outer surface 152 of the vanadium-based membrane 110 abuts and engages the inner surface 150 of the expansion section 146 until it reaches the point where it reaches the natural hydrogen expansion diameter of the vanadium-based membrane 110. In the transition section 148, the outer surface 152 of the hydrogenated vanadium-based membrane 110 expands from the constriction diameter C to the tapered surface 154 of the expansion section 146 in accordance with the shape / curvature of the transition section 148.

[0109] It should be understood that the length of the transition section 148 depends on the transition radius R and the average slope / angle of the angled section 145 of the expansion section 146. This length depends on the intersecting tangents between the curvature of the transition radius and the slope of the angled section 145. For the same transition radius R, the length of the transition section 148 increases with the increase of the expansion angle α, as will be described below with respect to FIG. 17.

[0110] The transition section 148 is disposed at the end of the constriction section 144 and at the beginning of the expansion section 146, and the surface of the constriction section 144 transitions to the tapered surface 154 of the angled section 145 of the expansion section 146. In one embodiment, the expansion angle α, as shown in FIG. 2, includes the curvature (including the transition radius R) provided by the transition section 148. In an alternative embodiment, the tapered surface 154 may include a curved surface or multiple curvatures or inclinations, although it does not have a linear inclination. For example, FIG. 2A illustrates an embodiment of a constriction collar 140A that includes an angled section 145A (here a curved section) and a transition section 148A that includes a continuous curved surface 154A. In this embodiment, the angled (curved) section 145A of the transition section 148A and the expansion section 146A may follow the same or a similar curvature and share a common radius. Nevertheless, it should be understood that in other embodiments, the transition section 148A may be on a different curvature than the angled (curved) section 145A that follows the transition section 148A. It should also be understood that features within FIG. 2A that are similar to those illustrated and described with respect to FIGS. 1 and 2 are given the same reference numbers and the description of those features applies equally to this embodiment. In embodiments where at least the expansion section is on at least one curvature, the expansion angle α (shown as α2 in FIG. 2A) includes the average expansion angle of that curvature and typically is a non-zero angle of less than 17.5 degrees, for example from 0.5 degrees to 17.5 degrees, preferably from 0.5 degrees to 6 degrees. Nevertheless, the expansion section 146A and its tapered / curved / inclined surface 154A will provide the same function as described above in that they will result in a diameter that gradually increases on average from the constriction diameter C to the expansion diameter D2 at the distal end 147 of the expansion section 146. In these embodiments, the average expansion angle may also include the curved section provided by the transition section 148.

[0111] As shown in FIG. 1, the constriction collar 140 also includes a collar fastening section 149 that extends over and covers a connection interface 132 configured to fasten onto a section of the connector 120. Here, the connector 120 includes a fastening formation, which in the illustrated embodiment comprises a thread 160. However, various other interengaging fastening configurations can also be used. The fastening section 149 comprises a cooperating fastening formation, also a thread 162 here, configured to interconnect the constriction collar fastening section 149 to the connector 120.

[0112] As described above, the vanadium-based membrane 110 includes vanadium or vanadium alloy tubes suitable for use as a hydrogen selective membrane, such as taught in U.S. Patent No. 10,590,516. As taught in that specification, the vanadium-based membrane can be formed from vanadium or a vanadium alloy. Typically, a particular vanadium metal or alloy is selected based on its suitability for use in a membrane separation device. In some embodiments, the vanadium-based membrane includes vanadium, aluminum having a content greater than 0 atomic % to 10 atomic %, and Ta having a content less than 0.01 atomic %, and includes a vanadium alloy having a ductility that elongates by more than 10%, preferably more than 11%. The vanadium alloy can further include a grain refinement element selected from Ti, Cr, Fe, Ni, or B having a content greater than 0 atomic % to 5 atomic %, preferably 0.2 atomic % to 4.5 atomic %. In some embodiments, the grain refinement element has a content of 0.1 atomic % to 2 atomic %, preferably 0.1 atomic % to 1 atomic %, more preferably 0.1 atomic % to 1 atomic %. In some embodiments, the vanadium-based membrane is coated with a Pd-based coating or a Pd-Au-based coating. Once again, the illustrated hydrogen separation membrane includes the vanadium-based membrane 110, which can likewise be formed from other metal membrane materials such as Group 5-based metals or metal alloys, such as tantalum or niobium.

[0113] Figure 3A presents an alternative (second) embodiment of the bonding and encapsulation arrangement of the present invention. This arrangement 100A includes many of the same features as the first embodiment shown in FIGS. 1 to 3, and similar features are given the same reference numerals as those used in FIGS. 1 to 3. It should be understood that the above description of the first embodiment for those features also applies equally to those similar features illustrated in FIG. 3A. In this embodiment, the constriction collar 140A is configured without the constriction section 144 (FIG. 1) present in the first embodiment. Similar to the first embodiment, the constriction collar 140A is configured to extend axially from at least the connection interface 132 and the weld connection 130, covering the vanadium-based film 110 with respect to the longitudinal axis X-X, from the constricted end 144A of the expansion section 146. The constriction collar 140A also extends over the connection interface 132 and the weld connection 130 and extends axially covering at least a portion of the vanadium-based film 110 and the connector 120 with respect to the longitudinal axis X-X. This second embodiment of the constriction collar 140A has the following interconnected sections: (1) an expansion section 146, (2) a transition section 148, and (3) a collar fastening section 149. Each of these sections will be described in more detail next.

[0114] Similar to the first embodiment, the expansion section 146 uses an inclined or curved portion to control the expansion of the vanadium-based membrane 110 that has been hydrogenated, and gradually expands the vanadium-based membrane 110 to its natural diameter as the vanadium-based membrane 110 extends away from the welded connection along the longitudinal axis X-X. Here too, the expansion section includes a transition section 148 and an angled section 145. The diameter of the constriction collar 100 expands from the constriction diameter C at the constriction end 144A of the expansion section 146 to the expansion diameter D2 at the other end of the expansion section 146. Similar to the first embodiment, the angled section 145 of the expansion section 146 has an inclined surface with an expansion angle α with respect to the longitudinal axis, including a non-zero angle of less than 17.5 degrees (i.e., an angle from greater than zero degrees to 17.5 degrees), for example, from 0.5 degrees to 17.5 degrees, preferably from 0.5 degrees to 6 degrees. Here too, the expansion diameter D2 is at least 1.01D, preferably at least 1.02D. However, if the expansion is intended to be greater than the maximum linear expansion, the expansion diameter D2 may be at least 1.05D. The length L2 of the expansion section 146 is then determined by the expansion angle α and the size of the expansion diameter D2 that the tapered portion must reach.

[0115] The constriction end 144A is located at the beginning of the expansion section 146 near the connection interface 132, and is the region of the constriction collar 140A where the inner surface 150 of the constriction collar 140 contacts or is separated from the outer surface 152 of the vanadium-based membrane 110. The inner surface of the constriction end 144A defines a constriction diameter C that is 0.95 to 1.05 times the outer diameter D of the vanadium-based membrane 110.

[0116] In this embodiment, the transition section 148 extends from the constricted end / portion 144A into the expansion section 146 and includes a curved surface 119 having a radius R in the range of at least 0.1D, typically from 0.1D to 10D. The curved surface gradually increases the expansion rate from the constricted diameter until it reaches its maximum at the angled section 145. The gradually increasing expansion rate by the curved surface 119 reduces the strain at the welded connection 130.

[0117] The inner surface 150 of the constriction collar 140 can also be configured to extend over the welded connection 130 and the connection interface 132, as shown in the embodiment illustrated in FIG. 3A. The constriction 143 of the constriction collar 140 can thus mechanically constrain any expansion of the welded connection during hydrogenation expansion and cyclic operation.

[0118] As shown in FIG. 3A, the constriction collar 140 also includes a collar fastening section 149 that extends over a connection interface 132 configured to fasten onto a section of the connector 120. Here, the connector 120 includes a fastening formation, which in the illustrated embodiment comprises a thread 160. However, various other interengaging fastening configurations can also be used. The fastening section 149 comprises a cooperating fastening formation, which is also here a thread 162, configured to interconnect the constriction collar fastening section 149 to the connector 120.

[0119] FIGS. 1 through 3A illustrate a welded connection 130 over a connection interface 132 between end sections 111 of a vanadium-based membrane 110, but it should also be understood that other types of connections can be used in place of the welded connection 130 with a constriction collar 140 operating in an equivalent manner as described above. For example, the welded connection can alternatively include any suitable gas-tight connection between their body portions, such as (but not limited to) a welded connection, a brazed connection, a threaded connection, an O-ring sealed connection, or the like.

[0120] Even when using the constriction collar 140 illustrated in FIGS. 1 to 3A, there may still be a chance of leakage occurring at the welded connection 130, and as a result, the ability to maintain high-purity hydrogen production may be lost. FIGS. 4 to 8 teach a third embodiment of the joining and sealing arrangement 200A and 200B of the present invention that is designed to have an additional sealing function in the event of a defect and / or flaw in the weld that can affect the weld after hydrogenation and the resulting expansion of the vanadium-based membrane 210.

[0121] In this embodiment, the constriction collars 240A and 240B can be configured to provide both mechanical constraints and have sections that provide a backup to sealing integrity to reduce the sole dependence on welding for sealing integrity. This helps to isolate the welded connection 230 from variations in external processing conditions. This secondary seal is designed to isolate the welded connection 230 and can provide an additional sealing backup layer / buffer layer in the event of a weld defect during cycle operation or other operating changes.

[0122] As shown in FIGS. 4 to 8, the constriction collars 240A and 240B have two different configurations designed for specific ends of the vanadium-based membrane 210 into which the constriction collars 240A and 240B are designed to fit. Thus, each vanadium-based membrane 210 includes the following. 1. A fluid end connector collar 240A that includes a tubular sealing extension end 270 designed to connect to the fluid / flange end of the vanadium-based membrane 210, and 2. A blind plug collar 240B that forms an end cap on the blind end of the vanadium-based membrane 210.

[0123] It should be understood that both the fluid end connector collar 240A and the blind plug collar 240B include the following features that are the same as those of the first embodiment. Features similar to those of the first embodiment are assigned numbers with 100 added to the same reference numbers, and it should be understood that the above description of the first embodiment regarding those features is equally applicable to those features illustrated in FIGS. 4 to 8. These features are as follows. (1) A vanadium-based membrane 210 including a vanadium or vanadium alloy tube suitable for use as a hydrogen selective membrane. The vanadium-based membrane 210 has an outer diameter (D) around the longitudinal axis X-X. (2) A connector 220 including a metal fluid connection joint (preferably a metal gas connection joint) formed from a metal or metal alloy different from the vanadium-based membrane 210, typically steel, stainless steel, nickel-chromium-iron alloy, brass, Inconel, Incoloy, or a combination thereof. The connector 220 includes a connector forming portion 222 configured to receive the end section 111 of the vanadium-based membrane 110. In the illustrated embodiment, the connector forming portion 222 includes an inclined section in the form of a frustum-shaped section. However, it should be understood that other configurations are possible. As will be described in more detail below, the exact configuration of the connector 220 for the fluid end connector collar 240A and the blind plug collar 240B is tailored to the function of each end (fluid end or blind end) of the vanadium-based membrane 210. (3) A welding connection portion 230 covering the connection interface 232 between the end section 211 of the vanadium-based membrane 210 and the end section 211 of the vanadium-based membrane 210 where the end sections of the vanadium-based membrane 210 substantially abut or overlap the adjacent surfaces of the connector forming portion 222. The welding connection portion 230 includes a continuous weld extending around the connection interface and covering the connection interface 232. (4) At least a constriction collar 240A, 240B extending from the connection interface 132 and the welded connection 130 and configured to extend axially covering the vanadium-based film 110 with respect to the longitudinal axis X-X. The illustrated constriction collar 140 includes a substantially cylindrical tube. However, it should be understood that the constriction collars 240A, 240B can have any suitable overall shape and configuration. The constriction collars 240A, 240B typically consist of at least one of steel, stainless steel, nickel-chromium iron alloy, brass, or combinations thereof. Each of the embodiments of the fluid end connector collar 240A and the blind plug collar 240B has interconnected sections, (A) a constriction section 244, (B) an expansion section 246, (C) a transition section 248, as described above for the first embodiment, and the details thereof are equally applicable to this second embodiment. The configurational difference from the first embodiment lies in the configuration of the constriction collar fastening section 249.

[0124] The fluid end connector collar 240A is illustrated in FIGS. 4 through 6. In this embodiment, the connector 220 includes a fluid connection fitting having a connection formation portion 222 formed at one end as described above, and a tubular extension section 223 extending longitudinally away from the connection interface to the distal end 225. The tubular extension 223 includes a threaded connector 260 near the connection formation portion 222 designed to threadably engage a connection section 251 of a collar fastening section 249 of the fluid end connector collar 240A. Here, the constriction collar fastening section 249 extends over the connection interface 232 to the first connection section 251. The fastening section 249 also has a cooperating fastening formation, also a thread 262 here, configured to interconnect the constriction collar fastening section 249 to the connector 220. Further, the constriction collar fastening section 249 also includes a threaded sealing end 265 configured to seal and interconnect a compression fitting 272 (e.g., a compression fitting such as a Hy-Lok style compression fitting or a Swagelok style connector), and seals between the tubular extensions 223 using a ferrule 274, preferably a graphite ferrule. The illustrated compression fitting 272 includes a sealing nut configured to threadably engage and fasten to the distal fastening end of the sealing section. However, any suitable compression fitting and cooperating fastening arrangement configuration can also be used to fit the compression fitting 272 onto the sealing end 265 of the fluid end connector collar 240A. The compression fitting 272 and the ferrule 274 are tightened onto the sealing end 265 of the fluid end connector collar 240A to form a fluid seal between the compression fitting 272, the ferrule 274, and a portion of the tubular extension 223. The ferrule 274 can have any suitable configuration. Thus, as shown in FIG. 4, the secondary seal around the welded connection 230 includes the following. (1) Upstream of the welded connection 230: When the vanadium-based tubes 210 expand upon hydrogenation and are mechanically constrained in those sections 244, 246, the sealing of the vanadium-based tubes 210 in the constriction section 244 and a portion of the expansion section 246 to the constriction collar 240A and (2) Downstream side of the welded joint 230: Seal between the compression joint 272, the ferrule 274, and a part of the tubular extension 223.

[0125] The blind plug collar 240B is illustrated in FIGS. 7 and 8. In this embodiment, the connector 220 includes a blind plug / end cap joint including a connection forming portion 222 at one end as described above, and a blind end 223A. This blind end 223A includes a solid section having a threaded connector 260A designed to be screwed with a connection section 251A of a color fastening section 249A of the blind plug collar 240AB. Here, the constricted color fastening section 249A extends covering the connection interface 232 on the first connection section 251A. The fastening section 249A also has a cooperating fastening forming section, which is also a thread 262A here, configured to interconnect the constricted color fastening section 249A to the connector 220. The constricted color fastening section 249 also includes a capped end 266 including a fastening section 249A configured to completely seal the blind end 223A of the connector 260A within the constricted collar 240B and a sealed blind cap extending therefrom. This configuration ensures that there are no leak points on the cap end side of the vanadium-based film 210.

[0126] The joining and sealing arrangement 100 illustrated in FIGS. 1 to 3 can be formed using the following method.

[0127] Step 1: Preparation of the vanadium-based film: A suitable vanadium-based membrane tube 110 is cut to a suitable length, and then each end is squared to form an end face 311 suitable for use at the end section 111 of the vanadium-based membrane 110 that overlaps with the adjacent faces of the connector forming part 122 of the connector 120. This is achieved by clamping the vanadium-based membrane tube 110 to a jig 300 that holds the tube perpendicular to the working surface 302 of a planar grinding disk 304 (or other equivalent grinding arrangement). This jig 300 is then held on the planar grinding disk 304, and the end face 311 is ground until the end face 311 of the tube 110 is square.

[0128] Step 2: Welding to form the joint / connection: The end section 111 of the vanadium-based membrane tube 110 is placed covering the inclined surface of the connector forming part 122 of the connector 120 as shown in FIG. 1, and the vanadium-based membrane tube 110 and the connector forming part 120 are in contact at the connection interface 132. That connection interface 132 is then welded, for example by laser welding, preferably autogenous (no filler wire is added), thereby forming a welded connection 130. In some embodiments, this welding was completed in two welds. The cross-section of the finished welded connection 130 is illustrated in FIG. 10. In this figure, the dashed line 310 shows the original shape of the vanadium-based membrane before welding, and the dashed line 312 shows the original shape of the stainless steel connector. Since the surface of the welded connection 130 is flush with or just below the surfaces of the vanadium-based membrane and the stainless steel connector, a snug-fitting collar 140 can slide over the welded connection.

[0129] Step 3: Fitting the snug-fitting collar: Finally, as illustrated and described with respect to FIGS. 1-3, the constriction collar 140 is fitted over the vanadium-based membrane tube 110 and the welded connection 130, extends from the connection interface, and extends axially covering the vanadium-based membrane tube 110 with respect to the longitudinal axis X-X. As shown in FIG. 1, the constriction collar 140 is positioned over the welded connection 130 and held on the connector forming portion 122 using the threaded connector 162 of the connector section 149.

[0130] After hydrogenation, the vanadium-based membrane 110 expands and the constriction collar 140 constrains the vanadium-based membrane 110 at the constriction section 144 near the welded connection 130. The tapered portion of the expansion section 146 provides an expansion that gradually progresses to the final unconstrained dimension of the vanadium-based membrane 110 when the vanadium-based membrane 110 is hydrogenated.

[0131] It should be understood that a similar method can also be implemented to form the joining and sealing arrangements 200A and 200B in accordance with the third embodiment of the present invention.

[0132] It should also be understood that the tubular membrane using the joining and sealing arrangement of the present invention can be incorporated into a tubular catalytic membrane reactor (CMR), as taught in U.S. Patent No. 10,590,516, the content of which is hereby incorporated by reference. As described in U.S. Patent No. 10,590,516, a CMR incorporating a tubular membrane can be used to selectively extract hydrogen from a hydrogen-containing gas such as syngas to produce a raffinate (syngas with reduced H2) and an H2 permeate.

[0133] (Example) (Example 1) Stress Analysis The joining and sealing arrangement structure 100 illustrated in FIGS. 1 to 3 was drawn in SolidWorks (Solidworks Simulation Professional (SSP) software package (Version 2021 Service Pack 5.1 is available from Dassault Systems SolidWorks Corporation, Waltham, Massachusetts, USA)), and the stress analysis was performed considering both the temperature from hydrogenation and the expansion of the vanadium-based film under typical operating pressure / temperature.

[0134] The axial and hoop stresses on the outer surface of the welded joint were based only on the model output from SolidWorks described above.

[0135] The results of the stress analysis are illustrated in FIG. 11 as the radial displacements of the constriction collar 140, the connector 120, and the vanadium-based film 110 when the vanadium-based film 110 expands from hydrogenation. In FIG. 11, the radial displacements are color-coded, with red indicating a larger displacement than blue. As shown in FIG. 11, the constriction collar 140 substantially restricts the significant expansion of the vanadium-based film 110 in the constriction section 144, and the largest radial displacements occur in the expansion section 146 and the transition radius section 148. The modeling results (transition from light blue to orange / red) indicate that the tapered portion serves as a means to allow the gradual expansion from the constrained state in section 144 to the fully natural expansion dimension in section 146.

[0136] (Example 2) Simulation of Stresses in Films and Welded Joints under Hydride Expansion Background When the vanadium component of the membrane undergoes a hydride formation process (also called hydrogenation, the absorption of hydrogen), significant expansion of the metal occurs with respect to the amount of hydrogen contained in the lattice. The components of different materials (stainless steel, vanadium stainless steel alloy welding) in the membrane mounting / sealing structure do not undergo the same scale of hydrogen absorption even if there is hydrogen absorption, so they do not undergo this expansion. Therefore, when the expansion rates are mismatched, significant stress is induced at the interface with the membrane during operation. This stress is attributed to past failures of both the weld and the membrane under various conditions.

[0137] Method of stress simulation There are several issues that prevent opportunities for physical material testing and measurement during operation. Therefore, in order to understand the stress at critical locations, a finite element analysis (FEA) study was conducted using the Solidworks Simulation Professional (SSP) software package (Version 2021 Service Pack 5.1, available from Dassault Systems SolidWorks Corporation, Waltham, Massachusetts, USA). It should be noted that since hydride lattice expansion is not a phenomenon supported by SSP itself, a custom method was required to emulate such expansion.

[0138] Simulation of materials under thermal expansion is a core function of SSP and enables modeling of the following effects expected under hydride expansion. · Isotropic expansion proportional to temperature (hydrogen content) · Internal stress profile depending on temperature gradient (hydrogen content gradient) · Contact behavior between materials with different thermal expansion coefficients (hydride expansion coefficients)

[0139] Since the mechanical properties of metals can change significantly at high temperatures, an analytical approach combining thermal expansion and hydride expansion was adopted to understand the possible failure mechanisms under operating conditions (both temperature and hydrogen under pressure). A nominal steady-state temperature of 325 °C was selected and the material properties were adjusted to reflect the expected reduction in tensile strength.

[0140] Experimental data on the properties of vanadium hydride were obtained from synchrotron radiation X-ray powder diffraction in situ (under non-atmospheric conditions) to i) measure hydrogen-induced lattice expansion and ii) perform synchrotron radiation analysis of vanadium hydride for hydride formation in vanadium-based alloys. The data were acquired for vanadium hydride formation at various temperatures and various hydrogen partial pressures and were used to estimate the unit cell volume under each condition and thus infer the hydrogen-induced lattice expansion / volume expansion. The experimental data were consistent with the expected maximum practical level of hydrogen absorption and the H / M or hydrogen-to-metal ratio was ~0.65. It should be noted that the ratio of hydrogen atoms to metal atoms (H / M) in vanadium-based films can be obtained from experimental data acquired using a Hiden Isochema Sieverts apparatus under various temperatures and hydrogen partial pressures. In this modeling, at the maximum practical degree of hydration expected for vanadium-based films (a hydrogen-to-metal ratio (H / M) of ~0.65 at 300 °C to 400 °C and a maximum H2 partial pressure of 15 bar), · a maximum volume expansion of the vanadium film of up to +15%, and · a maximum linear expansion of the vanadium film of up to +5% (E h ) were presented. In both cases, the degree of expansion varies as a function of the hydrogen uptake (i.e., the ratio of hydrogen absorbed to metal or H / M ratio).

[0141] To incorporate this value into the expansion analysis, a specific temperature-based coefficient (α h ) for hydride expansion in vanadium was

[0142]

Equation

[0143]

Number

[0144] is determined by. The thermal expansion coefficient known for vanadium

[0145]

Number

[0146] When combined with, this gives the combined expansion coefficient α r as follows. α r = α t + α h α r = 8 * 10 -6 + 1.67 * 10 -4

[0147]

Number

[0148] After completion, the deformed geometric shape of the 325 °C steady-state simulation of the unrestrained membrane section was checked against the expected overall expansion (thermal and hydride) and confirmed at ~5.24%.

[0149] The detailed model output of the stress components formed within the critical section of the membrane / joint assembly was examined and used to inform the welding parameters and stress relief color design, which focuses on reducing stress concentration and minimizing distortion at the weld.

[0150] The hoop and axial stresses were obtained via the standard output from the SolidWorks modeling software package (Version 2021 Service Pack 5.1 available from Dassault Systems SolidWorks Corporation, Waltham, Massachusetts, USA).

[0151] Results Figures 12 through 14(B) present the results of Solidworks modeling of hydride lattice expansion and hoop and axial stresses.

[0152] Figure 12 illustrates that the modeled stress components on the membrane and weld act on the vanadium-based membrane 110 and the welded connection 130 in both tensile (positive) and compressive (negative) axial and hoop stresses.

[0153] Figure 13 shows the modeled results representing, for the joining and sealing arrangement 100 illustrated in Figures 1 through 3 when the vanadium-based membrane 110 is hydrogenated, (A) the relationship between the axial stress on the inner surface of the vanadium membrane at the connection interface and the distance from the welded connection, and (B) the relationship between the hoop stress on the inner surface of the vanadium-based membrane 110 at the connection interface and the distance from the welded connection. The unhydrogenated outer diameter of the vanadium-based membrane 110 is 9.54 mm.

[0154] As shown in Figures 13(A) and 13(B), when the inner diameter of the constriction collar is too large (gap fit - 9.75 ID), large compressive axial stresses and high tensile stresses are observed at the vanadium-based membrane joint interface (welded connection). In these experiments, it was seen that collars >9.75 mm always failed, and the first of three membranes with a 9.65 mm collar maintained its strength after at least 1000 hours of operation after the vanadium-based membrane was hydrogenated, i.e., after hydrogen permeation began.

[0155] As shown in FIGS. 14(A) and 14(B), a smaller transition radius R concentrates the axial stress at that point, resulting in significantly high maximum stresses on both the inner and outer surfaces of the vanadium-based film 110. Therefore, the transition radius specification is currently designated as 10 mm, which is about 1 times the outer diameter of the vanadium-based film 110. However, moving to about 1.5 times the outer diameter of the vanadium-based film 110, i.e., 15 mm or more, would likely help further reduce the stress concentration profile.

[0156] (Example 3) Simulation of Stress Inflation Sections for Different Inflation Angles To determine the longitudinal bending stress of the inflation sections of the colors illustrated in FIG. 1 for different average inflation angles, modeling was performed using the Solidworks Simulation Professional (SSP) software package (Version 2021 Service Pack 5.1, available from Dassault Systems SolidWorks Corporation, Waltham, Massachusetts, USA). The modeling was performed for a transition radius of 5 mm (therefore, ~0.5D). The results of stress modeling for the longitudinal bending stress on the outer surface of the film at average inflation angles of 0.5, 1, 3, 5, 6, 10, and 17.5 degrees are presented in FIGS. 15 and 16. FIG. 15 models the stress from the end of the transition section, and FIG. 16 models the stress from the beginning of the transition section. Note that the lines for 10 degrees and 17.5 degrees are exactly overlaid on the lines shown in FIG. 15 and, in FIG. 16, are overlaid leaving the valley immediately after 0 mm.

[0157] As shown in FIGS. 15 and 16, the general rule appears to be that the smaller the angle of the angled section 145, the better the result of the longitudinal stress. However, this stress advantage needs to be balanced with the practical requirement of material waste. At very small angles, for example less than 0.5 degrees, there is a substantial amount of waste material covering most of the membrane.

[0158] As best shown in FIG. 15, there are the following two stress peaks for each average expansion angle. · The first peak at the "entry point" at the start of the tapered section (the point where the transition section intersects the angled section of the expansion section). · The second peak at the "departure point" where the membrane loses contact with the collar.

[0159] As shown in FIGS. 15 and 16, for small angles of the angled section 145, the peaks are well separated. As the angle increases, the peaks come together and overlap, resulting in undesirably high peak stresses.

[0160] (Example 4) Collar inner radius expansion rate The expansion rate (mm / mm) of the expansion section of the collar is modeled for the transition section with a radius of 5 mm and expansion angles of 1, 3, 5, 6, 10, 17.5 of the angled section 145, respectively, based on the expansion section illustrated in FIG. 1, with respect to the distance from the start of the transition radius (mm). The expansion rate increases along the transition section 148 until it reaches a maximum at the start of the angled section 145 from the narrow end. The angled section 148 has a constant expansion rate (which is a constant slope), which is the maximum expansion rate of the expansion section 146.

[0161] These results are illustrated in FIG. 17. As shown, the greater the expansion angle of the angled section 145 (the greater the expansion ratio), the longer the transition section 148 required. This length depends on the intersecting tangent between the curvature of the transition radius and the slope of the angled section 145 of the expansion section, and thus increases with the increase in the expansion angle.

[0162] The radial expansion ratio (mm / mm) of the angled section 145 with different angles modeled in FIG. 17 is the maximum expansion ratio for each expansion section 146 in FIG. 17. The expansion ratio of the transition section 148 increases to the maximum expansion ratio, which is at a point along the expansion section 146 where the transition section 148 intersects the angled section 145.

[0163] The above discussion applies to the radial expansion ratio in mm / mm of the expansion section, but also applies equally to the expansion angle of the expansion section 146. The expansion angle of the transition section 148 increases to the maximum expansion angle, which is at a point along the expansion section 146 where the transition section 148 intersects the angled section 145. The expansion angle of the angled section 145 can be considered the maximum expansion angle of the expansion section 146.

[0164] When the expressions "comprising", "including", "included", "containing" are used within this specification (including the claims), they are to be interpreted as specifying the presence of the stated features, integers, steps, or components, and not as precluding the presence of one or more other features, integers, steps, components, elements, or groups thereof.

Explanation of Reference Signs

[0165] 100 Joint and Sealing Arrangement Configuration 100A Arrangement Configuration 110 Vanadium-Based Film, Vanadium-Based Film Tube 111 End Section 119 Curved surface 120 Connector 122 Connector forming part 130 Weld connection part 132 Connection interface 140 Narrowing collar 140A Narrowing collar 143 Narrowing part 144 Narrowing section 144A Narrowing end 145 Angled section 145A Angled (curved) section 146 Expansion section 146A Expansion section 147 Distal end 148 Transition section, transition radius section 148A Transition section 149 Collar fastening section, fastening section 150 Inner surface 152 Outer surface 154 Tapered surface, inner diameter 154A Continuous curved surface 160 Thread 162 Thread 200A and 200B Joining and sealing arrangement 210 Vanadium-based film 211 End section 220 Connector 222 Connector forming part 223 Tubular extension section, tubular extension 223A Blind end 225 Distal end 230 Weld connection part 232 Connection interface 240A and 240B Narrowing collar 240AB Blind plug collar 244 Narrowing section 246 Expansion section 248 Transition section 249 Collar fastening section 249A Color fastening section 251 Connection section 251A Connection section 260 Threaded connector 260A Threaded connector 262 Thread 262A Thread 265 Threaded sealing end 266 Capping end 270 Tubular sealing extension end 272 Compression joint 274 Ferrule 300 Fixture 302 Working surface 304 Planar grinding disk 310 Dashed line 311 End face 312 Dashed line

Claims

**Claim 1** A joining and sealing arrangement for joining a hydrogen separation membrane to a metal connector and sealing them together, A metal hydrogen separation membrane mounted on or applied to a connector forming part around a longitudinal axis, wherein the connector is formed of a metal different from the hydrogen separation membrane, the hydrogen separation membrane has an outer diameter (D) around the longitudinal axis, and the hydrogen separation membrane and the connector forming part are in contact at a connection interface where the end face of the hydrogen separation membrane is near, substantially in contact with, or overlapping the adjacent face of the connector forming part, A connecting part connecting the hydrogen separation membrane and the connector forming part around the connection interface, A constriction collar extending at least from the connection interface and configured to extend axially covering the hydrogen separation membrane with respect to the longitudinal axis, An expansion section configured to extend axially covering the hydrogen separation membrane with respect to the longitudinal axis from a constricted end to an expanded diameter, the constricted end being configured to extend around the hydrogen separation membrane at or near the connection interface with respect to the longitudinal axis, and having an inner surface defining a constricted diameter (C) configured to extend around the outer surface of the hydrogen separation membrane, A constriction collar comprising the expansion section, Comprising, The expansion section includes a transition section extending from the constricted end and having a curved surface with a transition radius of at least 0.1D, The expansion section includes a section angled or curved such that the diameter of the constriction collar expands from the constricted diameter C to the expanded diameter including a diameter of at least 1.01D, the joining and sealing arrangement. **Claim 2** The joining and sealing arrangement according to claim 1, wherein the diameter of the constriction collar expands from the constricted diameter C to the expanded diameter constricted end with an average expansion angle with respect to the longitudinal axis including a non-zero angle of less than 17.5 degrees. **Claim 3** The constricted end comprises a constricted section configured to extend axially covering the hydrogen separation membrane from the connection end with respect to the longitudinal axis to the expansion section, the constricted section having an inner surface extending around the longitudinal axis at the constricted diameter, The joining and sealing arrangement according to claim 1 or 2, wherein the transition section extends from the transition between the constricted section and the expansion section. **Claim 4** The inner surface of the narrow section is configured to be spaced from the outer surface of the hydrogen separation membrane, preferably spaced substantially parallel thereto, the joining and sealing arrangement according to claim 3.

5. The hydrogen separation membrane has an outer diameter D, and the narrow diameter C includes a diameter from 0.95D to 1.05D, preferably from 0.99D to 1.05D, more preferably from 1D to 1.05D, the joining and sealing arrangement according to any one of claims 1 to 4.

6. The narrow section is configured to extend covering the hydrogen separation membrane from the connection interface to the transition section over at least 0.25D, preferably from 0.25D to 2D, more preferably from 0.25D to 1.5D, more preferably from 0.25D to 1D, the joining and sealing arrangement according to any one of claims 1 to 5.

7. The expansion diameter is at least 1.02D, preferably at least 1.05D, more preferably at least 1.1D, the joining and sealing arrangement according to any one of claims 1 to 6.

8. The average expansion angle is from 0.5 degrees to 6 degrees, preferably from 3 degrees to 5 degrees, the joining and sealing arrangement according to any one of claims 1 to 7 when dependent on claim 2.

9. The transition radius includes from 0.1D to 10D, preferably from 0.5D to 5D, more preferably from 1D to 5D, the joining and sealing arrangement according to any one of claims 1 to 8.

10. The expansion section extends by at least 0.2D with respect to the longitudinal axis, the joining and sealing arrangement according to any one of claims 1 to 9.

11. The expansion section extends by at least 0.3D, preferably at least 0.4D, more preferably at least 0.5D with respect to the longitudinal axis, the joining and sealing arrangement according to claim 10.

12. The outer diameter (D) of the hydrogen separation membrane is from 2 mm to 25 mm, preferably from 5 mm to 20 mm, and has a wall thickness from 0.05 mm to 1 mm, preferably from 0.1 mm to 1 mm, the joining and sealing arrangement according to any one of claims 1 to 11.

13. The narrow collar is configured to extend to a collar fastening section configured to cover the connection interface of the hydrogen separation membrane and fasten onto the section of the connector, and the collar fastening section comprises a fastening formation section configured to interconnect the narrow collar with the cooperative fastening formation section of the connector. The joining and sealing arrangement according to any one of claims 1 to 12.

14. The fastening formation section comprises a threaded connection section configured to fasten cooperatively onto the thread on the connector. The joining and sealing arrangement according to claim 13.

15. The narrow collar further comprises an end cap configured to form an end seal around the connector. The joining and sealing arrangement according to any one of claims 1 to 14.

16. The connector comprises a tubular extension extending longitudinally away from the connection interface. The narrow collar includes a sealing section configured to cover the tubular extension of the connector and extend to a distal fastening end. The narrow collar further comprises a compression joint configured to fasten to the distal fastening end of the sealing section, and the compression joint includes at least one ferrule configured to seal around a section of the tubular extension of the connector when the compression joint is fastened to the distal fastening end of the sealing section. The joining and sealing arrangement according to any one of claims 1 to 15.

17. The at least one ferrule includes a graphite ferrule. The joining and sealing arrangement according to claim 16.

18. The compression joint comprises a sealing nut configured to be screwed and fastened to the distal fastening end of the sealing section. The joining and sealing arrangement according to claim 16 or 17.

19. The sealing section comprises a fastening formation section configured to interconnect the narrow collar with the cooperative fastening formation section of the connector. The joining and sealing arrangement according to any one of claims 16 to 18.

20. The narrow collar is made of at least one of aluminum, aluminum alloy, steel, stainless steel, nickel-chromium-iron alloy, brass, or a combination thereof. The joining and sealing arrangement according to any one of claims 1 to 19.

21. The connector comprises at least one of steel, stainless steel, nickel-chromium iron alloy, brass, inconel, inconeloy, or a combination thereof, and the joining and sealing arrangement according to any one of claims 1 to 20.

22. The hydrogen separation membrane comprises a Group V-based metal or metal alloy, preferably a metal or metal alloy of vanadium, tantalum, or niobium, more preferably vanadium or a vanadium alloy, and the joining and sealing arrangement according to any one of claims 1 to 21.

23. The hydrogen separation membrane comprises vanadium, aluminum having a content of more than 0 atom% to 10 atom%, and Ta having a content of less than 0.01 atom%, and has a ductility that elongates by more than 10%, preferably more than 11%, and comprises a vanadium alloy, and the joining and sealing arrangement according to claim 22.

24. The hydrogen separation membrane is coated with a Pd-based coating or a Pd-Au-based coating, and the joining and sealing arrangement according to any one of claims 1 to 23.

25. The hydrogen separation membrane is tubular, and the joining and sealing arrangement according to any one of claims 1 to 24.

26. The outer diameter (D) of the hydrogen separation membrane is from 2 mm to 25 mm, preferably from 5 mm to 20 mm, and has a wall thickness of from 0.05 mm to 1 mm, preferably from 0.1 to 1 mm, more preferably from 0.2 mm to 0.8 mm, and even more preferably from 0.2 mm to 0.5 mm, and the joining and sealing arrangement according to any one of claims 1 to 25.

27. The connector is tubular, and the joining and sealing arrangement according to any one of claims 1 to 26.

28. The connector has a wall thickness of from 1 mm to 5 mm, preferably from 1 mm to 3 mm, more preferably from 1 mm to 2 mm, and the joining and sealing arrangement according to any one of claims 1 to 27.

29. The connector forming portion comprises an inclined or chamfered section configured to receive the end section of the hydrogen separation membrane thereon, and the joining and sealing arrangement according to any one of claims 1 to 28.

30. The connection portion includes a welded connection portion, and the joining and sealing arrangement according to any one of claims 1 to 29.

31. The joining and sealing arrangement according to claim 30, wherein the welded connection portion includes a continuous weld portion that extends covering the connection interface around the connection interface.

32. The joining and sealing arrangement according to claim 30 or 31, wherein the welded connection portion includes a laser welding connection portion, an electron beam welding connection portion, or an arc welding connection portion.

33. A method for joining and sealing a hydrogen separation membrane to a metal connector, comprising: mounting an end section of the metal hydrogen separation membrane on or against a connector forming portion of the connector, the connector being formed of a metal different from the hydrogen separation membrane, the hydrogen separation membrane having an outer diameter (D) around a longitudinal axis, and the hydrogen separation membrane and the connector forming portion contacting at a connection interface where the end face of the hydrogen separation membrane is near, substantially in contact with, or overlapping an adjacent face of the connector forming portion; joining the hydrogen separation membrane to the connector forming portion to join and seal the hydrogen separation membrane to the connector on the connection interface; placing a constriction collar on the hydrogen separation membrane to extend at least from the connection interface and axially extend covering the hydrogen separation membrane with respect to the longitudinal axis; and the constriction collar is an expansion section configured to axially extend covering the hydrogen separation membrane with respect to the longitudinal axis from a constricted end to an expanded diameter, the constricted end being configured to extend around the hydrogen separation membrane at or near the connection interface with respect to the longitudinal axis, having an inner surface defining a constricted diameter (C) configured to extend around an outer surface of the hydrogen separation membrane, the expansion section including a transition section extending from the constricted end and having a curved surface with a transition radius of at least 0.1D; the expansion section includes a section angled or curved such that the diameter of the constriction collar expands from the constricted diameter C to an expanded diameter including a diameter of at least 1.01D.

34. The method according to claim 33, using the joining and sealing arrangement according to any one of claims 1 to 32.

35. The connector includes a tubular extension portion that extends longitudinally away from the connection interface, and the constriction collar includes a sealing section configured to cover the tubular extension portion of the connector and extend to a distal fastening end. The method is The step of fastening a compression fitting to the distal fastening end of the sealing section, the compression fitting including at least one ferrule that seals around a section of the tubular extension portion of the connector when the compression fitting is fastened to the distal fastening end of the sealing section, the method according to claim 33 or 34, further including this step.

36. The method according to claim 35, wherein the at least one ferrule includes a graphite ferrule.

37. The method according to any one of claims 33 to 36, wherein the compression fitting includes a sealing nut configured to be screwed and fastened to the distal fastening end of the sealing section.

38. The method according to any one of claims 33 to 37, wherein the connector is made of at least one of steel, stainless steel, nickel-chromium iron alloy, brass, Inconel, Incoloy, or a combination thereof.

39. The method according to any one of claims 33 to 38, wherein the hydrogen separation membrane is tubular and the connector is tubular.

40. The method according to any one of claims 33 to 39, wherein the hydrogen separation membrane is welded to the connector on the connection interface.

41. The method according to claim 40, wherein the welded portion includes a continuous welded portion that extends around the connection interface and covers the connection interface.

42. The method according to claim 40 or 41, wherein the welded portion includes a laser welding connection portion, an electron beam welding connection portion, or an arc welding connection portion.

43. A hydrogen separation membrane system comprising a hydrogen separation membrane that is joined and sealed to a connector forming portion using the joining and sealing arrangement according to any one of claims 1 to 32.

44. A hydrogen separation membrane constriction collar configured to extend over the hydrogen separation membrane, the constriction collar being configured to extend over the hydrogen separation membrane from a connection interface between the hydrogen separation membrane and the connector, the constriction collar having a longitudinal axis. An expansion section configured to extend axially covering the hydrogen separation membrane with respect to the longitudinal axis from a narrow end to an expansion diameter, wherein the narrow end is configured to extend around the hydrogen separation membrane at or near the connection interface with respect to the longitudinal axis, and having an inner surface defining a narrow diameter (C) configured to extend around the outer surface of the hydrogen separation membrane, the expansion section comprising the expansion section includes a transition section extending from the narrow end and having a curved surface with a transition radius of at least 0.1C, the expansion section includes an angled or curved section extending from the transition section, the diameter of the narrow collar expands from the narrow diameter to the expansion diameter at an average expansion angle with respect to the longitudinal axis of the angled or curved section including a non-zero angle of less than 17.5 degrees, and the expansion diameter includes at least 1.01C, a hydrogen separation membrane narrow collar.

45. The expansion section extends at least 0.2C with respect to the longitudinal axis, the narrow collar according to claim 44.

46. The narrow end includes a narrow section configured to extend axially covering the hydrogen separation membrane from the connection end with respect to the longitudinal axis to the expansion section, the narrow section having an inner surface extending around the longitudinal axis at the narrow diameter C, The transition section extends from the transition between the narrow section and the expansion section, the narrow collar according to claim 44 or 45.

47. The hydrogen separation membrane has an outer diameter D, and the narrow diameter C includes a diameter from 0.95D to 1.05D, preferably from 0.99D to 1.05D, more preferably from 1D to 1.05D, the narrow collar according to any one of claims 44 to 46.

48. The narrow section is configured to extend covering the hydrogen separation membrane from the connection interface to the transition section over at least 0.25C, preferably from 0.25C to 2C, more preferably from 0.25C to 1.5C, more preferably from 0.25C to 1C, the narrow collar according to any one of claims 44 to 47.

49. The expansion diameter is at least 1.02C, preferably at least 1.05C, more preferably at least 1.1C, for the stenosis collar according to any one of claims 44 to 48.

50. The average expansion angle is from 0.5 degrees to 6 degrees, preferably from 3 degrees to 5 degrees, for the stenosis collar according to any one of claims 44 to 49.

51. The transition radius includes from 0.1C to 10C, preferably from 0.5C to 5C, more preferably from 1C to 5C, for the stenosis collar according to any one of claims 44 to 50.

52. The expansion section extends by at least 0.3C, preferably at least 0.4C, more preferably at least 0.5C, with respect to the longitudinal axis, for the stenosis collar according to any one of claims 44 to 51.

53. The stenosis collar includes a collar fastening section configured to fasten onto the section of the connector, and the collar fastening section includes a fastening formation section configured to interconnect the stenosis collar with the cooperative fastening formation section of the connector, for the stenosis collar according to any one of claims 44 to 52.

54. The fastening formation section includes a threaded connection section configured to fasten cooperatively onto the thread on the connector, for the stenosis collar according to claim 53.

55. The stenosis collar further includes an end cap configured to form an end seal around the connector, for the stenosis collar according to any one of claims 44 to 54.

56. A sealing section configured to cover the connector and extend to a distal fastening end, and A compression joint configured to fasten to the distal fastening end of the sealing section, the compression joint including at least one ferrule configured to seal around the section of the connector when the compression joint is fastened to the distal fastening end of the sealing section, a compression joint The stenosis collar further includes, for the stenosis collar according to any one of claims 44 to 55.

57. The at least one ferrule includes a graphite ferrule, for the stenosis collar according to claim 56.

58. The compression joint includes a sealing nut configured to be screwed and fastened to the distal fastening end of the sealing section, for the stenosis collar according to claim 56 or 57.

59. The sealing section includes a fastening formation section configured to interconnect the constriction collar to the mating fastening formation section of the connector. The constriction collar according to any one of claims 56 to 58.

60. The constriction collar according to any one of claims 44 to 59, wherein the constriction collar has a tubular, preferably substantially cylindrical configuration.

61. The constriction collar according to any one of claims 44 to 60, wherein the constriction collar consists of at least one of aluminum, aluminum alloy, steel, stainless steel, nickel-chromium-iron alloy, brass, or a combination thereof.

62. A hydrogen separation membrane constriction collar when used on a joint between a hydrogen separation membrane and a metal connector, wherein the constriction collar is configured to extend covering the hydrogen separation membrane from a connection interface between the hydrogen separation membrane and the connector, the constriction collar has a longitudinal axis, An expansion section configured to axially extend covering the hydrogen separation membrane with respect to the longitudinal axis from a constricted end to an expanded diameter, the constricted end is configured to extend around the hydrogen separation membrane at or near the connection interface with respect to the longitudinal axis, and has an inner surface defining a constricted diameter (C) configured to extend around an outer surface of the hydrogen separation membrane. The expansion section Comprises The expansion section includes a transition section extending from the constricted end and having a curved surface with a transition radius of at least 0.1C. The expansion section includes an angled or curved section extending from the transition section, and the diameter of the constriction collar expands from the constricted diameter to an expanded diameter including a diameter of at least 1.01C. The constriction collar.

63. A method of joining and sealing a hydrogen separation membrane to a metal connector, Mounting an end section of a metal hydrogen separation membrane onto or against a connector formation section of a connector, the connector being formed of a metal different from the hydrogen separation membrane, the hydrogen separation membrane having an outer diameter (D) around the longitudinal axis, and the hydrogen separation membrane and the connector formation section being in contact at a connection interface where the end face of the hydrogen separation membrane is near, substantially in contact with, or overlapping an adjacent face of the connector formation section. The step Bonding the hydrogen separation membrane to the connector forming portion, bonding and sealing the hydrogen separation membrane to the connector on the connection interface; Placing the constriction collar according to any one of claims 44 to 62 on the hydrogen separation membrane so as to extend at least from the connection interface and axially cover the hydrogen separation membrane with respect to the longitudinal axis; A method comprising.

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