Welded joint between metal hydrogen separation membrane and metal connector

Abstract

A weld joint between a metal connector and at least a metal core of a metal hydrogen separation membrane, the weld joint comprising a fusion weld formed by and located between the metal connector and at least the metal core of the metal hydrogen separation membrane, wherein the connector may be formed of a different metal or metal alloy than the metal core of the hydrogen separation membrane, and wherein the fusion welding portion includes a sealing portion providing a continuous seal between the metal connector and at least the metal core of the metal hydrogen separation membrane, and the welding metal of the sealing part contains less than 40 mass% of the metal from the metal core of the metal hydrogen separation membrane.

Description

TECHNICAL FIELD

[0001] A welded joint between a metal hydrogen separation membrane and a metal connector and a composition thereof, and a method of joining (e.g. sealably joining) a metal hydrogen separation membrane to a metal connector are disclosed. The joint can be particularly suitable for joining and sealing a tubular membrane (e.g. a vanadium-based tubular membrane) to a stainless steel gas fitting. However, it will be appreciated that the joint can be used to join and seal a hydrogen separation membrane of any metal type to a metal fitting or body of any type. BACKGROUND

[0002] The following discussion is intended to facilitate an understanding of the background. However, it will be appreciated that the discussion is not an acknowledgement or admission that any of the material referred to was part of the common general knowledge as at the priority date of the application.

[0003] Hydrogen (H2) is not naturally occurring in large quantities and in industrial practice it can be produced by conversion of hydrocarbon fuels (e.g. coal, petroleum or natural gas), by decomposition of ammonia (NH3) or by electrochemical decomposition of water. Each of these production routes produces an impure gas stream comprising H2as well as unreacted feed gas (e.g. CH4, H2O, NH3) and by-products (e.g. CO2, CO and N2). For many applications, H2must be separated from this mixed gas stream.

[0004] Membrane-based separation technology can be used to separate H2from the mixed gas stream. Broadly speaking, a membrane is a near two-dimensional structure that is selectively permeable to one species. In the case of gas separation, the membrane allows one species to selectively permeate (H2) while blocking other species (e.g. CO, CO2, H2O, N2, etc.). Hydrogen-selective membranes can be produced from inorganic, metallic or ceramic materials, each with characteristic hydrogen flux, operating temperature and selectivity.

[0005] Palladium is the best known alloy membrane material, with the ability to permeate hydrogen at 300 to 600 °C, while being resistant to synthesis gas species such as CO and H2O. However, the high cost of palladium (AUD 80 to 160 / g Pd (June 2023)) has driven research towards minimising its consumption, most notably by alloying with less expensive metals, and by minimising thickness by depositing very thin (< 5 μm) layers on a support structure with very fine pores.

[0006] Many other metals exhibit very high hydrogen permeability, most notably vanadium, titanium, tantalum, niobium, and zirconium. At 400°C, these metals have hydrogen permeability approximately two orders of magnitude higher than palladium, and their raw material costs are significantly lower. Among these metals, vanadium has the widest range of alloys, meaning it offers the broadest range of options for modifying alloy properties to meet the requirements of vanadium-based films. An example of a vanadium-based film is taught in the applicant's U.S. Patent Publication US20150368762A1.

[0007] Vanadium-based membranes are typically connected to and sealed with another tube or conduit to provide a flow path for extracted H2 and prevent non-H2 gaseous substances from passing through the membrane. The sealing / engagement of the membrane with the connection is crucial for the successful application of vanadium-based membrane technologies in separating high-purity hydrogen from hydrogen-containing gas feeds. In this regard, high-purity hydrogen suitable for fuel cell electric vehicles (FCEVs) requires a purity of >99.97%, as described in ISO 14687, and maximum limits on individual gaseous substances such as NH3 and N2. Failure of the seal leads to contamination of hydrogen products, meaning the membrane is no longer suitable for producing high-purity hydrogen.

[0008] A technique for joining and sealing tubular vanadium-based films utilizes brazing between a V-shaped film and a metal fitting (e.g., an end cap or connector). International Patent Publication No. WO2019000026A1 teaches an example of a configuration for joining a vanadium-based film to a metal fitting. This patent disclosure teaches a brazing technique for joining and sealing a vanadium-based film to a metal connector, wherein a filler or brazing metal is used to form a bridging portion of the filler metal between the vanadium-based film and the connector at the joining interface.

[0009] WO2019000026A1 also teaches (in paragraphs 99-102) that this brazing process was developed preferentially over laser welding. It should be understood that the brazing process involves melting brazing (filler) material into the joint without melting the adjacent metal parts being joined, to join these metals using brazing metal. Brazing does not melt the substrate to be joined around the joint. In contrast, welding involves melting adjacent metal parts around the joint to fuse the molten material together. As described in WO2019000026A1, it was found that the microstructure of both vanadium tubes and stainless steel was altered in the heat-affected zone (HAZ) by direct laser welding. At the joint, a weak region is formed in the vanadium tube, where the tube can crack or otherwise break. This indicates that the direct laser welding technique used in the comparative example of WO2019000026A1 is unsuitable for joining and sealing vanadium-based films to stainless steel or other metal joints.

[0010] Austrian Patent Publication No. AT12132U1 teaches another laser-welded joint between a hydrogen separation membrane and an adjacent metal connector. This publication teaches forming a welded joint between a metal connector and a porous carrier tube for forming a hydrogen separation membrane with a defined radial penetration zone. Both the carrier tube and the metal connector are taught to be formed of an iron alloy, preferably a Plansee ITM alloy (Fe-Cr alloy). The welding technique and parameters do not take into account the welding difficulties caused by welding the carrier tube / hydrogen separation membrane to a connector formed of different metal materials.

[0011] Therefore, it is desirable to provide an improved and / or alternative connection between the hydrogen separation membrane or component forming the hydrogen separation member and the adjacent metal connector. Summary of the Invention

[0012] The following describes welding joints and related compositions and methods that can be used to join and seal metal hydrogen separation membranes to metal connectors or fittings with different compositions, particularly fittings formed of different metals or metal alloys, such as stainless steel fittings.

[0013] A first aspect provides a weld joint between a metal connector and at least a metal core of a metal hydrogen separation membrane. The weld joint includes a fusion weld portion formed by the metal connector and at least the metal core of the metal hydrogen separation membrane and located between them. The metal connector may be formed of a metal or metal alloy different from the metal core of the hydrogen separation membrane. Additionally, the fusion weld portion may include a sealing portion that provides a continuous seal between the metal connector and at least the metal core of the metal hydrogen separation membrane. The sealing portion may have a weld metal composition comprising less than 40% by mass of metal from the metal core of the metal hydrogen separation membrane.

[0014] It should be understood that weld metal includes the material constituting the weld. The weld is formed from molten metal that forms a weld pool, which is then cooled and solidified to form weld metal that connects adjacent components (here, the metal hydrogen separation membrane and the metal connector surrounding the connection interface). Therefore, weld metal includes the metal of the solidified weld pool.

[0015] It should also be understood that the fusion weld of a welded joint includes the weld joint between the metal connector and the metal core, and therefore can be a fusion weld comprising the metal components of both the metal connector and the metal core. In this sense, the fusion weld is formed between and by the metal material of the metal connector and the metal core. The fusion weld can be formed from the material of the metal connector and the metal core of the metal hydrogen separation membrane, and between the two. This type of fusion weld produces a molten pool comprising the metal hydrogen separation membrane and the material of the adjacent connector surrounding the connection interface. This type of weld effectively fuses the two components together around the connection interface. Therefore, the integrity of the seal may depend significantly on the nature of the fusion weld forming the seal and its weld metal.

[0016] It should also be understood that the sealing portion of the weld is the part of the weld metal that extends between the metal connector and at least the metal core of the metal hydrogen separation membrane, forming a continuous seal between them. In embodiments, the sealing portion may include at least 80% of the weld metal, for example, 80% to 99% or 80% to 100% of the weld metal. In some embodiments, the sealing portion may include at least 90% of the weld metal, for example, 90% to 99% or 90% to 100% of the weld metal. In some embodiments, the sealing portion may include at least 95% of the weld metal, for example, 95% to 99% or 95% to 100% of the weld metal. In this sense, not all of the weld metal content can form part of the sealing portion. For example, the weld metal may include one or more isolation sections that may have different compositions because the section is isolated from the majority of the weld metal body under the complete welding method / process. In embodiments, the weld may include, for example, a heel, finger, or other extension isolated from the majority of the weld metal body under the complete welding method / process. These isolation sections may not form part of the seal of the welded metal.

[0017] It should also be understood that "continuous seal" refers to a sealing joint between the metal hydrogen separation membrane and the metal connector, where the welded joint connects the two components, and this welded joint substantially prevents any gas (including any hydrogen inclusions therein) from passing through the welded joint and the connection between the metal hydrogen separation membrane and the metal connector formed by the welded joint. In this respect, a welded joint that substantially prevents any gas (including any hydrogen inclusions therein) from passing through generally refers to a welded joint that maintains pressure when the membrane is internally pressurized to 10 bar N2. For example, in some embodiments, the welded joint can be tested to determine whether it maintains 10 bar N2 at room temperature for at least 12 hours, preferably at least 24 hours. If applicable, a leak detection test can be used to detect leaks (see below a description of an example of such a test using the Swagelok Snoop Liquid Leak Detector). In embodiments, the welded joint can provide a continuous, leak-free seal between the metal connector and at least the metal core of the metal hydrogen separation membrane. In this case, "leak-free seal" should be understood to include the welded joint, which substantially prevents any gas from passing through the welded joint. In practice, the leakage characteristics of a weld can be tested using a pressure test with a gas such as nitrogen (N2). In this sense, a leak-free weld or leak-free weld joint is a weld that has been subjected to 10 bar of N2 at room temperature for at least 12 hours. It should be understood that room temperature refers to a temperature of 15-25°C. The leak-proof characteristics of a weld joint largely depend on the weld itself, which is continuous between the components around the joint interface and is also substantially free of defects, i.e., without cracks, inclusions, or voids that could allow gases (including hydrogen inclusions in these gases) to leak through.

[0018] Against this backdrop, the first aspect addresses the limitations previously considered to exist in welding metallic hydrogen separation membranes to metal connectors formed of different metals or metal alloys, such as welding vanadium-based tubular hydrogen separation membranes to stainless steel connectors. In an embodiment, this type of weld joint can be created between different metal components to provide a reproducible, continuous leak-proof seal at the interface between the metallic hydrogen separation membrane and the adjacent connector.

[0019] In this regard, the integrity of the weld joint, and more specifically, whether the weld joint forms a substantially leak-free seal, can be affected by the final composition of the weld metal, particularly the final composition of the sealing portion of the weld joint. The metal from the metal hydrogen separation membrane can include metals or metal alloys, and if the composition of these metals or alloys comprises a substantial portion of the weld metal, it can have a detrimental effect on the composition of the weld metal. For example, when the metal from a stainless steel-based connector is alloyed with stainless steel, the vanadium content from vanadium-based metal hydrogen separation can produce weld metal with undesirable defect-forming properties. Therefore, it may be preferable, for example, to reduce the mass contribution of the metal from the metal hydrogen separation membrane within the weld metal composition relative to the mass contribution of the connector material.

[0020] Therefore, in this first aspect, the sealing portion of the weld metal may contain less than 40% by mass of the metal core from the metal-hydrogen separation membrane. It should be understood that 40% by mass of metal can be considered as the average composition of the entire weld metal mass of the weld joint provided by the sealing area. In embodiments, therefore, when the weld metal of the sealing portion contains less than 40% by mass of the metal from the metal-hydrogen separation membrane, a weld portion may be formed between the metal-hydrogen separation membrane and the metal connector so as to be substantially free of cracks, inclusions, and voids. In some embodiments, when the weld metal of the sealing portion contains less than 40% by mass of the metal from the metal-hydrogen separation membrane, a weld portion may be formed between the metal-hydrogen separation membrane and the metal connector so as to be free of cracks, inclusions, and voids. In some embodiments, when the weld metal of the sealing portion contains less than 40% by mass of the metal from the metal-hydrogen separation membrane, a weld portion may be formed between the metal-hydrogen separation membrane and the metal connector, and this weld portion may be substantially leak-free, or leak-free in some forms.

[0021] However, in some embodiments, the properties of the weld metal are improved even with a smaller mass contribution from the metal core within the weld metal composition. Therefore, in some embodiments, the weld metal of the seal comprises less than 35% by mass of the metal core. In other embodiments, the weld metal of the seal comprises less than 30% by mass of the metal core. In still other embodiments, the weld metal of the seal comprises less than 25% by mass of the metal core. It should be understood that in some embodiments, the weld metal of the seal may include one of the following: less than 38% by mass, less than 34% by mass, less than 33% by mass, less than 31% by mass, less than 28% by mass, less than 23% by mass, or less than 20% by mass of the metal core.

[0022] It should also be understood that the mass% used throughout this instruction manual can be expressed as weight% (and therefore can be used interchangeably). The weight of an object is equal to its mass multiplied by its gravity. Therefore, when expressed as a percentage, mass% is equivalent to weight%.

[0023] In embodiments, the composition of the weld metal can be substantially uniform across the volume of the weld metal in the sealing portion. In this sense, the weld metal in the sealing portion of the fusion weld can have a substantially consistent or uniform volume composition throughout its entire volume / material. However, where compositional variations may exist in the weld metal, ideally, the weld metal in the sealing portion does not contain isolated pockets with a composition exceeding 40% by mass of the metal core from the metal hydrogen separation membrane or the desired mass percentage limit as defined above. Therefore, in embodiments, no portion of the volume composition of the weld metal in the sealing portion includes no more than 40% by mass of the metal core, preferably no more than 35% by mass of the metal core. In some embodiments, no portion of the volume composition of the weld metal in the sealing portion includes 30% by mass of the metal core, preferably no more than 25% by mass of the metal core. In some embodiments, no portion of the volume composition of the weld metal in the sealing portion includes 35% by mass of the metal core, preferably no more than 20% by mass of the metal core. It should be understood that volumetric composition includes the composition of the entire volume of weld metal in the sealing portion of the weld joint.

[0024] In embodiments, the weld metal of the sealing portion can have a substantially homogeneous composition throughout the entire volume of the weld metal. In this sense, the composition of the weld metal of the weld joint can be substantially homogeneous throughout the entire volume of the weld metal. In other words, the weld metal of the sealing portion can have a substantially homogeneous composition throughout the entire volume of the weld metal. In embodiments, the weld metal of the sealing portion can have a substantially homogeneous composition throughout the entire volume of the main body of the weld metal of the sealing portion. In some forms, the weld metal of the sealing portion can have a homogeneous composition throughout the entire volume of the main body of the weld metal of the sealing portion. It should be understood that the main body of the weld metal of the sealing portion can be the volume or mass of metal remote from the periphery or edge of the weld joint. The main body of the weld metal of the sealing portion includes a certain volume of the internal portion of the weld metal of the weld joint. The peripheral and / or edge regions of the weld metal typically include a composition that transitions from the composition of the main body of the weld metal to the composition of the adjacent metal component, and therefore may not conform to the substantially homogeneous composition of the main body of the weld metal. Additionally, (as described above) the weld metal can include one or more isolation segments that can have different compositions because this portion is isolated from the complete welding method / process that the majority of the main body of the weld metal undergoes. These isolation sections do not form part of the main body of the weld metal of the sealing portion. Therefore, the main body of the weld metal of the sealing portion includes at least 90% of the volume of the weld metal of the sealing portion, for example, 90% to 95%, preferably 90% to 96%, more preferably 90% to 98%.

[0025] As described above, the weld joint typically comprises a solidified mixture of materials at and around the weld joint. In this case, the weld joint may substantially comprise metal from the metal hydrogen separation membrane and the metal connector, preferably from the metal core of the metal hydrogen separation membrane and the metal connector. Therefore, the metal of the weld metal, excluding the metal from the metal hydrogen separation membrane, typically comprises most (if not substantially all) of the metal composition from the metal connector. In many embodiments, the weld joint may comprise an autogenous weld. Here, the weld metal substantially comprises metal from the metal connector and the metal hydrogen separation membrane originating from the metal at and near the connection interface of the weld joint. However, it should be understood that in some embodiments, other filler materials may be used in the weld joint to supplement the material added to the molten pool forming the weld metal. Therefore, in some embodiments, the weld joint may be formed as a weld joint having at least one filler metal, preferably at least one filler wire. The composition of the filler metal may be selected to enhance or optimize the properties of the weld metal. In embodiments, the filler metal may be selected from at least one of the following: stainless steel, steel, aluminum-silicon, copper, copper alloys, gold-silver alloys, nickel alloys, or silver.

[0026] The connector can be formed / made of any suitable metal or metal alloy, with the hydrogen separation membrane to be mounted on it. In some embodiments, the connector may be made of at least one of the following: steel, stainless steel, nickel-chromium-iron alloy, brass, Inconel, Incoloy, or combinations thereof. Examples of suitable materials include austenitic stainless steel, preferably 300 series stainless steel, such as 303, 304, or 316 stainless steel.

[0027] For connectors made of stainless steel or Inconel, a vanadium content of less than 35% by weight is preferred, which can mitigate or prevent cracking. However, it should be understood that other metal combinations may have different maximum contents, which may lead to cracking.

[0028] It should be understood that the metal core of the hydrogen separation membrane can be the base metal material forming the hydrogen separation membrane. In some embodiments, the hydrogen separation membrane may include the core itself (e.g., the hydrogen separation membrane may consist of a core). In other embodiments, the metal core may include one or more other layers, such as a coating layer on the surface of the metal core.

[0029] Metal hydrogen separation membranes and their metal cores may comprise a metal capable of hydrogen separation by dissociative chemisorption of hydrogen on a surface, followed by diffusion of hydrogen to the opposite side of the membrane via a metal lattice driven by a partial pressure drop, and then by recombination of hydrogen atoms and desorption from the permeate side. The metal membrane can separate and produce hydrogen (with high permeability, purity, and recovery) from H2 / CO2 mixtures, H2 / N2 / NH3 mixtures, or any other H2-containing gas mixture. In embodiments, at least the metal core of the hydrogen separation membrane may comprise a Group 5 (Group V) based metal or metal alloy, preferably vanadium, tantalum, or niobium metal or metal alloy. In some embodiments, the hydrogen separation membrane may be formed of vanadium or a vanadium alloy. Typically, the specific vanadium metal or alloy can be selected based on its suitability for use in membrane separation devices. In some embodiments, the hydrogen separation membrane comprises a vanadium alloy containing vanadium, aluminum at a content greater than 0 to 10 atomic percent, and Ta at a content less than 0.01 atomic percent, and has a ductility of greater than 10%, preferably greater than 11%. The vanadium alloy may also contain grain-refining elements selected from Ti, Cr, Fe, Ni or B, in a content greater than 0 to 5 atomic percent, preferably 0.2 to 4.5 atomic percent. In some embodiments, the content of the grain-refining element is 0.1 to 2 atomic percent, preferably 0.1 to 2 atomic percent, more preferably 0.1 to 1 atomic percent.

[0030] The hydrogen separation membrane can have any suitable configuration. In an exemplary embodiment, the hydrogen separation membrane and its metal core can be tubular. In embodiments, the metallic hydrogen separation membrane can include a thin-walled hydrogen separation membrane, preferably a thin-walled tubular hydrogen separation membrane. In some embodiments, the thin-walled tubular hydrogen separation membrane can include a tubular metal core having an outer diameter of 2 to 25 mm, preferably 3 to 20 mm, and a wall thickness of 0.05 to 1 mm, preferably 0.1 to 1 mm. In some embodiments, the wall thickness of the metal core of the hydrogen separation membrane can be 0.1 to 1 mm, preferably 0.2 to 0.8 mm, more preferably 0.2 to 0.5 mm. It should be noted that in these thin-walled embodiments, the weld joint can be characterized as a weld joint from thick to thin.

[0031] In embodiments, the metal core comprises a non-porous body, preferably a non-porous tube. The metal core of the core material forming the hydrogen separation membrane can typically be formed from a non-porous fluid seal (e.g., a tube). It should be understood that hydrogen separation membranes formed from Group 5 based materials or the like separate hydrogen from hydrogen through diffusion through the material. The permeation of hydrogen through this type of metal membrane consists of hydrogen molecules (H2) dissociating into atoms (H) on the membrane, H diffusing within the metal of the membrane, and H recombinating back into H2 on the other side of the membrane. This process requires the material to provide a solid, such as a dense metallic body, to allow this diffusion to occur. Hydrogen will leak through the pores of the porous body, thus the hydrogen separation membrane will not function properly. Therefore, in embodiments, the metal core comprises a fluid seal, such as an airtight body, preferably a fluid-sealed tube, such as an airtight tube. In some embodiments, the metal core comprises a dense body, preferably a dense tube. In some embodiments, the metal core comprises a solid body, preferably a solid tube.

[0032] A weld joint can be formed between the metal core of the hydrogen separation membrane and the metal connector, or between the hydrogen separation membrane and the metal connector. In some embodiments, a weld joint can be formed between the metal core of the main core material forming the hydrogen separation membrane and the metal connector before other layers are applied to the metal core, to form the final metal-coated structure of the hydrogen separation membrane. It should be understood that "metal core" refers to the core metal material that can form the hydrogen separation membrane. This core material can preferably be coated with one or more layers to form the final metal-coated structure of the hydrogen separation membrane. In some embodiments, the metal core of the hydrogen separation membrane can be coated with a Pd-based coating, such as a Pd coating or a Pd alloy coating, such as a Pd-Au-based coating. This Pd-based coating (e.g., a Pd coating or a Pd-Au-based coating) can be applied to the metal core before forming the weld joint or after forming the weld joint with the connector. Therefore, a weld joint can be formed between the hydrogen separation membrane (including the metal core and any other layers already applied to the metal core) and the metal connector. For example, in some embodiments, the metal core may include a vanadium body, such as a vanadium tube, having at least one palladium or palladium alloy coating applied to one or more outer surfaces to form the final metal-coated structure of the hydrogen separation membrane.

[0033] The connector can have any suitable configuration. In many embodiments, the connector may include metal fittings, such as connecting fittings or end cap fittings, and preferably metal fluid connection fittings, more preferably metal gas connection fittings. In an exemplary embodiment, the connector may be tubular. The connector can have any suitable size. In embodiments, the connector wall thickness is 1 mm to 5 mm, preferably 1 mm to 3 mm, or more preferably 1 mm to 2 mm.

[0034] The connector body can have any suitable configuration. In embodiments, the connector body may include a sloped or beveled end section configured to receive a hydrogen separation membrane thereon. In exemplary embodiments, the connector body may include an angled, sloping end of the connector body having a reduced diameter. This sloping or beveled section onto which at least the metal core forming the hydrogen separation membrane can be mounted. In some embodiments, the sloping or beveled portion may include a truncated conical portion. In other embodiments, the connection interface may include a substantially flat end face of the metal core of the hydrogen separation membrane, which may be positioned parallel to or adjacent to a substantially flat abutment surface of the connector body.

[0035] The connection configuration between the metal core and / or the metal hydrogen separation membrane and the metal connector can take many forms. In one embodiment, the metal core of the metal hydrogen separation membrane can be mounted on or abut against the connector molding body of the connector, with the metal core and the connector molding body contacting at the connection interface, wherein the end face of the metal core can be close to, substantially adjacent to, or overlap the adjacent face of the connector molding body; and a weld joint connects at least the metal core of the hydrogen separation membrane and the connector around the connection interface. However, it should be understood that other connection configurations are also possible, and the invention should not be limited to this specific configuration.

[0036] The weld joint around the connection interface between at least the metal core of the hydrogen separation membrane and the connector may include a fusion weld. The weld joint can be formed using any suitable welding technique, such as laser welding, arc welding (e.g., TIG), or electron beam welding. The weld joint may include a continuous weld portion surrounding and extending circumferentially above the connection interface. This forms a continuous fusion weld seal at the connection interface between at least the metal core of the hydrogen separation membrane and the connector molding body. In some embodiments, the weld may be self-contained (without added filler material). Similarly, in other embodiments, filler material may be used in the weld joint, such as at least one of stainless steel, steel, aluminum-silicon, copper, copper alloys, gold-silver alloys, nickel alloys, or silver.

[0037] In some embodiments, the end face of at least the metal core of the hydrogen separation membrane at the interface may include a substantially right-angled edge. A right-angled edge can be advantageous because the profile can be easily and consistently machined, thereby improving reproducibility and repeatability.

[0038] In embodiments, the connector molding body may include tapered, beveled, or chamfered sections configured to receive end sections of a hydrogen separation membrane thereon. In some embodiments, the bevel of the tapered section may be in the form of a truncated conical section. When the connector molding body includes a tapered surface, the tapered surface may have a taper angle of 15 to 60°, preferably 15 to 45°, more preferably 15° to 30°, and also preferably about 30°. The taper on the connector molding body can be advantageously designed to allow variation in both the diameter and thickness of the metal core of the hydrogen separation membrane. Additionally, the taper angle can be optimized to allow other materials of the connector to melt into the molten pool, thereby minimizing the concentration of metal (e.g., vanadium) from the metal core in the molten pool (and thus minimizing the associated risk of cracking).

[0039] The weld joint can be joined in any suitable configuration and filled with welding material. In an exemplary embodiment, the weld joint can be formed as an underfilled weld, i.e., including an underfilled weld. It should be understood that by underfilling, it means that the weld joint does not extend (protrude) above the surface of the metal core / hydrogen separation membrane. The weld joint is below the outer surface of the metal core / hydrogen separation membrane, preferably forming a dip or recess therein.

[0040] A first aspect of the embodiment provides a welded joint between a metal connector and at least a metal core of a metal hydrogen separation membrane, the welded joint comprising a fusion weld portion formed by the metal connector and at least the metal core of the metal hydrogen separation membrane and provided therebetween for a continuous seal. The metal connector is formed of a metal or metal alloy different from the metal core of the hydrogen separation membrane. Furthermore, the weld metal of the welded joint comprises less than 40% by mass of the metal from the metal core of the metal hydrogen separation membrane.

[0041] A first aspect of the embodiment may provide a weld joint between a metal connector and at least a metal core of a metal hydrogen separation membrane, the weld joint comprising a fusion weld portion formed by the metal connector and at least the metal core of the metal hydrogen separation membrane and therebetween, wherein the connector is formed of a metal or metal alloy different from the metal core of the hydrogen separation membrane, and wherein the fusion weld portion includes a sealing portion that provides a continuous seal between the metal connector and at least the metal core of the metal hydrogen separation membrane, the sealing portion having a weld metal composition comprising less than 40% by mass of metal from the metal core of the metal hydrogen separation membrane.

[0042] A second aspect provides a method for joining and sealing at least a metal core of a hydrogen separation membrane to a metal connector. This method can be used to form a continuous weld seal, such as a fusion weld seal, between a metal connector and at least a metal core of the metal hydrogen separation membrane. Such a continuous weld seal may include a leak-free weld seal. The method may include mounting or abutting against a connector body of a metal connector, the connector being formed of a metal or metal alloy different from the metal core. The metal core and the connector body may contact at a connection interface, wherein the end face of at least a metal core of the hydrogen separation membrane may be close to, substantially adjacent to, or overlap an adjacent face of the connector body. The method may include welding at least a metal core of the hydrogen separation membrane to the connector using a weld (e.g., a fusion weld) to form a weld joint at and above the connection interface, the weld comprising a weld metal composition containing less than 40% by mass of metal from the metal core.

[0043] In this method, at least the metal core of the hydrogen separation membrane can be joined to a metal (e.g., stainless steel) connector using a suitable joining or connecting method, such as welding methods like laser welding, arc welding (e.g., TIG), or electron beam welding, to produce a welded portion comprising a weld metal composition containing less than 40% by mass of the metal from the metal core of the hydrogen separation membrane.

[0044] It should be understood that the second aspect may include any one or a combination of the above-described features related to the welding composition described with respect to the first aspect.

[0045] Similar to the first aspect, the weld metal of the sealing portion of the fusion weld may contain less than 40% by mass of the metal core from the metal hydrogen separation membrane. Likewise, it should be understood that 40% by mass refers to the average composition over the total mass of the weld metal of the sealing portion of the weld joint. However, in many embodiments, the properties of the weld metal are improved with even smaller mass contributions from the metal from the metal hydrogen separation membrane within the weld metal composition. Therefore, in embodiments, the weld metal of the sealing portion includes at least one of the following: less than 35% by mass of the metal core; less than 30% by mass of the metal core; or less than 25% by mass of the metal core. It should be understood that in some embodiments, the weld metal of the sealing portion may include one of the following: less than 39% by mass, less than 38% by mass, less than 34% by mass, less than 33% by mass, less than 28% by mass, less than 23% by mass, or less than 20% by mass of the metal core from the metal hydrogen separation membrane.

[0046] In embodiments, in the sealing portion of the welded joint, the weld metal of the sealing portion can have a substantially uniform or homogeneous volume composition throughout its entire volume / material. However, where compositional variations may exist in the weld metal, ideally, the weld metal of the sealing portion does not contain isolation cavities having a composition exceeding 40% by mass of the metal core from the metal hydrogen separation membrane or the desired mass percentage limit as defined above. Therefore, in embodiments, no portion of the volume composition of the weld metal of the sealing portion includes no more than 40% by mass of the metal core, preferably no more than 35% by mass of the metal core. In some embodiments, no portion of the volume composition of the weld metal of the sealing portion includes 30% by mass of the metal core, preferably no more than 25% by mass of the metal core. In some embodiments, no portion of the volume composition of the weld metal of the sealing portion includes 33% by mass of the metal core, preferably no more than 20% by mass of the metal core.

[0047] In embodiments, the weld metal of the sealing portion can have a substantially homogeneous composition throughout the entire volume of the weld metal. In this sense, the composition of the weld metal of the weld joint can be substantially homogeneous throughout the entire volume of the weld metal. In other words, the weld metal of the sealing portion can have a substantially homogeneous composition throughout the entire volume of the weld metal. In embodiments, the weld metal of the sealing portion can have a substantially homogeneous composition throughout the entire volume of the main body of the weld metal of the sealing portion. In some forms, the weld metal of the sealing portion can have a homogeneous composition throughout the entire volume of the main body of the weld metal. It should be understood that the main body of the weld metal of the sealing portion can be the volume or mass of metal spaced apart from the periphery or edge of the weld joint. The main body of the weld metal of the sealing portion includes a certain volume of the internal portion of the weld metal of the weld joint. The peripheral and / or edge regions of the weld metal typically include a composition that transitions from the composition of the main body of the weld metal to the composition of the adjacent metal component, and therefore may not conform to the substantially homogeneous composition of the main body of the weld metal. Therefore, the main body of the weld metal includes at least 90% of the volume of the weld metal of the sealing part, for example, 90% to 95% of the volume of the weld metal of the sealing part, preferably 90% to 96%, more preferably 90% to 98%.

[0048] As described in the first aspect, the weld joint between at least the metal core of the hydrogen separation membrane and the connector may include a fusion weld connection. The weld joint is formed by at least one of the following: laser welding, arc welding (e.g., TIG), or electron beam welding. The weld joint may include a continuous weld portion surrounding the connection interface and extending circumferentially above the connection interface. In embodiments, the weld joint may be formed using at least one continuous weld pass around the connection interface. This forms a continuous fusion weld seal at the connection interface between at least the metal core of the hydrogen separation membrane and the connector molding body. In some embodiments, the weld may be self-contained (without added filler material). In other embodiments, a filler material may be used in the weld joint, such as at least one of aluminum-silicon, copper, copper alloys, gold-silver alloys, nickel alloys, or silver.

[0049] In some embodiments, the weld joint may be formed by a single weld pass at, around, or near the joint interface. In other embodiments, at least two weld passes may be used to form the weld joint at, around, or near the joint interface, and one or both weld passes may be consecutive weld passes. In some embodiments, the weld joint may be formed using two consecutive weld passes at or around the joint interface. In any case, the at least two weld passes may include:

[0050] The first pass weld forms a first pass composition between at least the metal core of the hydrogen separation membrane and the connector; and

[0051] The second pass weld can dilute the first pass weld composition with additional metal from the connector. In this way, the second pass weld can be used to reduce the metal composition of the hydrogen separation membrane's metal core in the weld metal from the seal to, for example, less than 40% by mass of the metal from the metal core.

[0052] The first weld can be used to substantially fuse at least the metal core of the hydrogen separation membrane to the connector.

[0053] The second weld bead can be used to form a continuous seal between the metal core of the metal hydrogen separation membrane and the connector. The second weld bead can also be used to dilute the molten pool with more metal from the connector. Therefore, the second weld bead can be configured to produce a substantially uniform weld metal composition (e.g., extending from the membrane to the connector in the sealing portion of the weld). In this sense, the second weld bead can be used to introduce more metal mass from the connector material, and thus reduce the metal mass of the metal core in the weld metal of the sealing portion, and thus reduce the risk of cracking of the alloy composition that may be caused by undesirable metal mass from the metal core. This can be achieved, for example, by aiming the molten pool more towards the connector material, i.e., further towards the connector side of the connection interface. Furthermore, remelting the molten pool in the second weld bead helps to distribute the metal more uniformly throughout the molten pool, thereby producing a more uniform composition through the weld metal.

[0054] Various parameters can be varied to achieve the desired composition of the weld metal. In some embodiments, at least two consecutive weld passes include a laser weld pass using a laser beam, wherein the second weld pass employs a laser beam width wider than that of the first weld pass. While not wishing to be limited to any single theory, it is believed that a wider laser beam size can increase the melting / dilution of the connector metal and reduce the metal mass from the core in the molten pool to below a desired amount / concentration (e.g., below 40%). In embodiments, the second weld pass may reduce the metal mass from the core in the molten pool to below at least one of the following: 38% by mass, 36% by mass, 35% by mass, 33% by mass, 30% by mass, 25% by mass, or 20% by mass of metal. In embodiments, the second weld pass may reduce the metal mass from the core in the molten pool to below 35%. In embodiments, the second weld pass may reduce the metal mass from the core in the molten pool to below 30%. In embodiments, the second weld pass may reduce the metal mass from the core in the molten pool to below 25%. In one implementation, the second weld can reduce the metal mass of the metal core in the molten pool to less than 20%.

[0055] In a specific embodiment, the first weld pass may have a weld focus located at or near the connector interface between the metal hydrogen separation membrane and the connector, such as a laser weld focus. When using laser welding, a tight / narrow laser beam width can be used; for example, the laser beam will be tighter / narrower than a subsequent second weld pass (if used) (see below). The function of a tight / narrow laser beam width can be to generate a focused and deep-penetrating laser beam at that focus. The applied laser power can be applied after multiple waveforms. In an embodiment, the applied laser power can follow a pulse waveform. This pulse waveform may have an initial peak that decreases on the curve to reduce the applied laser power as the first weld pass proceeds.

[0056] In a specific embodiment, the second weld bead may have a laser focus positioned further away from the connector interface between the metal-hydrogen separation membranes compared to the welding focus of the first weld bead. In another embodiment, the welding focus of the second weld bead may be located within the connector spaced apart from the connector interface. For example, compared to the first weld bead, the welding focus of the second weld bead may be located at half the distance by which the beam diameter / width of the laser beam width of the second weld bead increases. This can be used to ensure that the position of the edge of the laser beam on the metal-hydrogen separation membrane remains the same for both the first and second weld beads. The laser application power can be applied again after multiple waveforms. In another embodiment, the laser application power may follow a pulse waveform. This pulse waveform may be applied with a constant laser power.

[0057] The connector, metal core, and hydrogen separation membrane may have the features defined above with respect to the first aspect. The connector may be formed of any suitable metal, such as steel, stainless steel, nickel-chromium-iron alloy, brass, Incoloy, or at least a combination thereof.

[0058] Similarly, the metal core and / or hydrogen separation membrane may comprise any suitable hydrogen separation metal or alloy. In embodiments, at least the metal core of the hydrogen separation membrane may comprise a Group V-based metal or metal alloy, preferably vanadium, tantalum, or niobium metal or metal alloy, more preferably vanadium or vanadium alloy. In some embodiments, at least the metal core of the hydrogen separation membrane may be formed of vanadium or a vanadium alloy, such as a vanadium alloy comprising vanadium, aluminum in a content greater than 0 to 10 atomic percent, and Ta in a content less than 0.01 atomic percent, and having a ductility of greater than 10% elongation, preferably greater than 11%. In some embodiments, the vanadium alloy also comprises a grain-refining element selected from Ti, Cr, Fe, Ni, or B, in a content greater than 0 to 5 atomic percent, preferably 0.2 to 4.5 atomic percent. The metal core of the hydrogen separation membrane may also be coated in a Pd-based coating or a Pd-Au-based coating. In many embodiments, the metal core and the hydrogen separation membrane are tubular. Similarly, in many embodiments, the connector may be tubular. The connector molding body may have any suitable configuration. In one embodiment, the connector body includes a beveled or chamfered section configured to receive at least an end section of a metal core on which a hydrogen separation membrane is received.

[0059] In one embodiment, the second aspect can provide a method for bonding and sealing at least a metal core of a hydrogen separation membrane to a metal connector, the method comprising:

[0060] At least the end section of the metal core of the metal hydrogen separation membrane is mounted on or abuts against the connector body of the metal connector, the connector being formed of a metal or metal alloy different from the metal core of the hydrogen separation membrane, the metal core and the connector body contacting each other at a connection interface, in which the end face of at least the metal core of the hydrogen separation membrane is close to, substantially adjacent to or overlaps with the adjacent face of the connector body;

[0061] At least the metal core of the hydrogen separation membrane is welded to the connector to form a welded joint at and above the connection interface. The welded joint includes a fusion weld portion, which includes a sealing portion that provides a continuous seal between the metal connector and at least the metal core of the metal hydrogen separation membrane. The sealing portion has a weld metal composition comprising less than 40% by mass of metal from the metal core of the metal hydrogen separation membrane.

[0062] This forms a continuous weld seal between the metal connector and at least the metal core of the metal hydrogen separation membrane.

[0063] The third aspect also relates to a gas separation membrane system incorporating a hydrogen separation membrane, which can be joined and sealed to a connector molded body using a welded joint according to the first aspect and / or a welded joint formed by the method according to the second aspect.

[0064] The sealing and joining configuration of this invention can be used to enable the assembly of a hydrogen separation tubular membrane into a catalytic membrane reactor (CMR) or membrane separator for the selective separation of hydrogen from a mixed gas stream (containing hydrogen and other gases), thereby producing high-purity hydrogen in the permeate stream from the membrane (suitable for FCEV refueling applications). Related methods can provide means to connect the hydrogen separation membrane to other metal structures (pipe connectors, pipe ends, etc.) to form a hydrogen separation system (in the form of a CMR) while maintaining seal integrity, i.e., maintaining mechanical integrity / robustness through multiple operating cycles.

[0065] The fourth aspect provides at least one of the following: a catalytic membrane reactor (CMR) or membrane separator comprising at least one hydrogen separation membrane, said hydrogen separation membrane being joined and sealed to a connector using a welded joint according to the first aspect and / or a welded joint formed by the method according to the second aspect.

[0066] The hydrogen separation membrane of the fourth aspect can have any suitable configuration chosen based on specific advantages, the advantage of which is that the configuration can be provided to a specific CMR or membrane separator configuration.

[0067] CMR is essentially a two-dimensional device that guides syngas or ammonia (if catalytic cracking ammonia) through a catalyst bed adjacent to the membrane along one dimension. Flat membranes can be produced more easily and cheaper than tubular membranes, but have a larger sealing area because the membrane is sealed around its outer edge. This sealing configuration provides a large sealing area and can therefore be prone to leakage between the raffinate and permeate streams. Tubular membranes make it possible to use tubular CMRs and thus reduce the sealing area. In tubular reactors, 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 also apply to membrane separator configurations.

[0068] In some embodiments, the hydrogen separation membrane described with respect to each aspect may have a tubular configuration, such as including a tube. These tubular membranes may have any suitable dimensions as described above. In some embodiments, the thin-walled tube may include a tube with an outer diameter of 2 to 25 mm, preferably 3 to 20 mm, and a wall thickness of 0.05 to 1 mm, preferably 0.1 to 1 mm. In an exemplary embodiment, the tubular membrane may include a thin-walled tube comprising a vanadium alloy containing vanadium, aluminum in a content greater than 0 to 10 atomic percent, and Ta in a content less than 0.01 atomic percent, and having a ductility with an elongation greater than 10%, preferably greater than 11%. In some embodiments, the hydrogen separation membrane may be coated in a Pd-based coating or a Pd-Au-based coating.

[0069] It should be understood that the alloy content and mechanical properties of the hydrogen separation membrane in the fourth aspect are the same as those described above for the first and second aspects, and should be understood to apply equally to this fourth aspect. Attached Figure Description

[0070] Specific examples of the invention will now be described with reference to the accompanying drawings, in which:

[0071] Figure 1 A cross-sectional view of a type of hydrogen separation membrane configuration is shown, which includes a welded joint between the hydrogen separation membrane and the connector.

[0072] Figure 1A A schematic diagram is provided showing the tapered portion of the connector and the right-angled edge of the hydrogen separation membrane (at the connection interface where the weld joint may be located).

[0073] Figure 2 A flat connection surface is formed on the end of a vanadium-based tube used for joining and sealing configurations.

[0074] Figure 3 An optical microscope image of a cross-section of a weld joint between the end of the vanadium-based film and the connector is provided.

[0075] Figure 4 Provided for: forming the first weld bead Figure 1 A schematic diagram (4A) of the connection interface between the hydrogen separation membrane and the connector device of the welded joint; and a pulse shape (4B) for applying the laser beam.

[0076] Figure 5 Provided for: forming the second weld bead Figure 1 A schematic diagram (5A) of the connection interface between the hydrogen separation membrane and the connector device of the welded joint; and a pulse shape (5B) for applying the laser beam.

[0077] Figure 6For welded joints with only a single weld pass between vanadium film tubes and stainless steel connectors, the following are provided: (A) EDS line scan analysis of the molten pool (elemental composition is shown in mass %); and (B) corresponding SEM images of the weld cross section (line 210 depicts the EDS line scan path).

[0078] Figure 7 For the weld joint between the vanadium film tube and the stainless steel connector after the second weld pass, the following are provided: (A) EDS line scan analysis of the molten pool (elemental composition is shown in mass %); and (B) corresponding SEM image of the weld section (line 215 depicts the EDS line scan path).

[0079] Figure 8 An example of a type of laser welding machine that can be used to form welded joints is shown. This laser welding machine has a modified shroud (not shown) to accommodate a 1100 mm long hydrogen separation membrane.

[0080] Figure 9 It shows that it can be used Figure 8 The laser welding machine shown is equipped with a clamping assembly for holding the membrane and fittings used in automated laser welding operations.

[0081] Figure 10 For another weld joint with only a single weld bead between a vanadium film tube and a stainless steel connector, the following are provided: (A) EDS line scan analysis of the molten pool (elemental composition shown in mass %); (B) SEM image of the joint along the EDS line scan path; and (C) corresponding SEM image of the weld cross section (line 410 depicts the EDS line scan path).

[0082] Figure 11 For the weld joint between the vanadium film tube and the stainless steel connector after the second weld pass, the following are provided: (A) EDS line scan analysis of the molten pool (elemental composition is shown in mass %); (B) SEM image of the joint along the EDS line scan path; and (C) corresponding SEM image of the weld cross section (line 415 depicts the EDS line scan path).

[0083] Figure 11A SEM backscattered image (AsB) is provided, showing the grain structure of the weld joint between the vanadium film tube and the stainless steel connector after the second weld bead, which has been used with... Figure 11 The welding joint shown is formed using a similar procedure.

[0084] Figure 12For a single-pass weld joint between a vanadium membrane tube and an Inconel 600 connector, the following are provided: (A) EDS line scan analysis of the molten pool (elemental composition shown in mass %); (B) SEM image of the joint along the EDS line scan path; and (C) corresponding SEM image of the weld cross section (line 410 depicts the EDS line scan path).

[0085] Figure 13 For the weld joint between the vanadium membrane tube and the Inconel 600 connector after the second weld pass, the following are provided: (A) EDS line scan analysis of the molten pool (elemental composition shown in mass %); (B) SEM image of the joint along the EDS line scan path; and (C) corresponding SEM image of the weld cross section (line 415 depicts the EDS line scan path).

[0086] Figure 13A SEM backscattered image (AsB) is provided, showing the grain structure of the weld joint between the vanadium film tube and the Inconel 600 connector after the second weld bead, which has been used with... Figure 13 The welding joint shown is formed using a similar procedure. Detailed Implementation

[0087] A joint (e.g., a welded joint and a combination thereof) and a method for joining and sealing a metal hydrogen separation membrane (or at least its metal core) to a metal connector made of different metals (e.g., stainless steel) are described.

[0088] Hydrogen separation membranes include metal membranes that can be configured to separate and produce hydrogen (with high permeability, purity, and recovery rate) from H2 / CO2 mixtures, H2 / N2 / NH3 mixtures, or any other H2-containing gas mixtures. The metal core of some of these hydrogen separation membranes may comprise a Group 5 (Group V) based metal or metal alloy, such as vanadium, tantalum, or niobium metal or metal alloy. Useful examples of suitable metal cores for hydrogen separation membranes include vanadium or vanadium alloys, which will be illustrated by example in the remainder of the specification. However, it should be understood that in some forms, the invention can be applied more generally to other metal hydrogen separation membranes, particularly other Group 5 metals or metal alloys.

[0089] One example of the applicant's metal membrane technology (MMT) is based on a palladium (Pd)-coated vanadium (V) tube that forms a hydrogen separation membrane. The vanadium tube forms the metal core of this hydrogen separation membrane, which can be coated with a Pd-based coating (e.g., a Pd coating) or a Pd alloy coating (e.g., a Pd-Au alloy catalytic coating). The hydrogen separation membrane tube may require seals at both ends to form a sealed hydrogen-containing membrane and is connected to an H2 product extraction tube. This seal can be achieved by welding metal connectors (typically stainless steel fluid fittings) to each end of the hydrogen separation membrane tube. The connectors can be welded to the vanadium tube before or after the Pd / Pd-Au-based catalytic coating is applied.

[0090] However, any connection between this type of hydrogen separation membrane tubing and the connector is ideally configured to account for hydrogen expansion. Vanadium-based hydrogen separation membranes (e.g., vanadium-based hydrogen separation membrane tubing) can exhibit linear (dimensional) expansion of approximately +5%, and when hydrogenated at normal operating temperatures / pressures, they can expand in volume by approximately +15% compared to conditions without hydrogen. Other metallic hydrogen separation membranes, such as those formed from Group 5 metals and their alloys, exhibit similar linear and volumetric expansion upon hydrogenation. This expansion can impose significant strain and stress on the weld joint between these types of hydrogen separation membranes and the adjacent connector, to a degree sufficient to affect the seal and the integrity of the joint around the sealed weld joint.

[0091] In view of the aforementioned problems with the hydrogenation expansion of the hydrogen separation membrane, the applicant has developed a sealing method and a hydrogen separation connection configuration comprising (1) a welded joint (the subject of this patent specification) that creates an advantageous continuous leak-free seal between the hydrogen separation membrane and an adjacent connector / fluid fitting; and (2) a constriction collar that can be advantageously used to mechanically limit the hydrogenation expansion of the hydrogen separation membrane at and near the welded joint. This constriction collar is the subject of the applicant's co-pending international patent application entitled "Arrangement for Joining and Sealing a Metallic Hydrogen Separation Membrane to a Metallic Connector" published in International Patent Publication WO2024 / 007057, the contents of which are to be understood as incorporated herein by reference. When hydrogen is introduced into the hydrogen separation membrane, the hydrogenated hydrogen separation membrane (tube) will expand within the constriction collar, and this expansion will be confined to the limits of the inner surface of the constriction collar.

[0092] Figure 1 An example of a hydrogen separation membrane configuration 100, including a welded joint 130, is shown. The shown configuration 100 includes:

[0093] (1) Hydrogen separation membrane

[0094] The hydrogen separation membrane (exemplified herein as vanadium-based membrane 110) preferably comprises a vanadium or vanadium alloy tube, which can be configured to be used as a hydrogen-selective membrane, as taught, for example, in U.S. Patent No. 10,590,516, the contents of which should be understood to be incorporated herein by reference. The vanadium-based membrane can be formed from a metal core tube comprising vanadium or a vanadium alloy. Typically, the specific vanadium metal or alloy can be selected based on its suitability for use in a membrane separation device. In specific examples, the metal core may comprise a vanadium alloy comprising: vanadium; aluminum in a content greater than 0 to 10 atomic percent; and Ta in a content less than 0.01 atomic percent, and having a ductility of greater than 10% elongation, preferably greater than 11%. The vanadium alloy may also contain grain-refining elements selected from Ti, Cr, Fe, Ni, or B in a content greater than 0 to 5 atomic percent, preferably 0.2 to 4.5 atomic percent. In some embodiments, the content of the grain-refining element is 0.1-2 atomic percent, preferably 0.1-2 atomic percent, more preferably 0.1-1 atomic percent. In some embodiments, the vanadium metal core may be coated in a Pd-based coating or a Pd-Au-based coating, forming a catalytic coating on the surface of the core material. However, it should be understood that other vanadium or vanadium alloys can also be used for hydrogen-selective membranes / hydrogen separation membranes. Similarly, it should be understood that although the illustrated hydrogen separation membrane includes a vanadium-based membrane 110, membrane 110 (and its metal core) can also be formed of other metallic membrane materials, such as Group 5 metals or metal alloys (e.g., tantalum or niobium).

[0095] The vanadium-based membrane 110 and its metal core may include a non-porous tube, thereby providing a solid, fluid-impermeable substrate, such as a dense metal substrate (through which hydrogen diffusion occurs). The illustrated vanadium-based membrane 110 has an outer diameter (D) around a longitudinal axis XX. This outer diameter D is the outer diameter of the vanadium-based membrane 110 when it is in an unhydrogenated state (i.e., not in a hydrogenated expansion state). In embodiments, the vanadium-based membrane 110 may include a thin-walled tube comprising a tube with an outer diameter of 2 to 25 mm and a wall thickness of 0.1 to 1 mm. However, it should be understood that, as described above, other configurations may also be used.

[0096] (2) Connector

[0097] Connector 120 can be fitted to each end of the hydrogen separation membrane tube to allow fittings such as gas conduits or end caps to be attached thereto. The illustrated connector 120 comprises a metal fluid connection fitting (preferably a metal gas connection fitting) formed of a metal or metal alloy different from the metal core of the vanadium-based membrane 110. Examples of suitable metals or metal alloys that can form connector 120 include steel, stainless steel, nickel-chromium-iron alloys, brass, Incoloy, or combinations thereof. The illustrated connector 120 (the entire fitting) includes a connector molded body 122 (the end section of connector 120 forming part of the connection interface with the vanadium-based membrane 110), which is configured to receive at least the end section 111 of the metal core of the vanadium-based membrane 110 thereon. In the illustrated embodiment, connector molded body 122 includes a beveled section in the form of a truncated conical portion. However, it should be understood that other configurations are also possible. As described in more detail below, the shown end section 111 of the vanadium-based film 110 can be configured to have right-angled edges 111A. However, it should also be understood that other end section configurations can also be used.

[0098] (3) Welded joint

[0099] The weld joint 130 shown may be located at and above the connection interface 132 between at least the end segment 111 of the metal core of the vanadium-based film 110 and the connector molded body 122, wherein the end segment 111 of the metal core of the vanadium-based film 110 substantially abuts or overlaps the abutment surface of the connector molded body 122. This weld joint (also referred to as a welded connection) 130 may include a continuous weld portion extending circumferentially around and above the connection interface 132. The weld joint 130 may be formed using any selected welding technique that produces a favorable weld metal composition between the connector and at least the metal core of the vanadium-based film 110. Examples of different welding processes for forming this weld joint 130 are described in more detail below.

[0100] (4) Constraint collar

[0101] The constraint collar 140 may also be optionally used in a connection configuration configured to extend at least from the connection interface 132 and the weld joint 130 and axially over the vanadium-based film 110 relative to the longitudinal axis XX. In the illustrated embodiment, the constraint collar 140 extends over the connection interface 132 and the weld joint 130 and axially over at least a portion of the vanadium-based film 110 and the connector 120 relative to the longitudinal axis XX. The illustrated constraint collar 140 comprises a substantially cylindrical tube. However, it should be understood that the constraint collar can have any suitable overall shape and configuration. Details of this constraint collar are also covered in the applicant's co-pending international patent application cited above.

[0102] Although this weld joint 130 is designed for use in conjunction with the constraint collar 140, it should be understood that the range of weld joints can be used to join alternative configurations and designs of hydrogen separation membranes to adjacent connectors.

[0103] An example of welded joint 130 and an example of a method for forming welded joint 130 will now be discussed in more detail.

[0104] First, the welded joint 130 shown includes a fusion weld portion. For example... Figure 3 The optical microscopic cross-section shown is optimal, indicating that this type of weld comprises a solidified mixture of metal from and around the weld joint 130. The weld metal of the weld joint 130 is formed from a metal hydrogen separation membrane (in... Figure 3 The example shown is vanadium tube 111) and metal connector (in Figure 3 A molten mixture of metals, exemplified as stainless steel fitting 122, is formed. However, it should be understood that in some embodiments, other filler materials may be used in the weld to supplement the material added to the molten pool forming the weld metal, such as one or more filler metals as described above.

[0105] This example relates to a weld joint 130 on a connection interface 132 between at least the end section 111 of the metal core of a vanadium-based membrane 110 and a connector forming body 122. This weld joint 130 can be formed using various suitable welding techniques, such as fusion welding (e.g., laser welding, electron beam welding, or arc welding or similar techniques), to create a weld that connects and seals at least the metal core of the hydrogen separation membrane 110 to the connector 120, for example, from a vanadium membrane to a stainless steel fitting. When the weld metal of the sealing portion of the weld joint 130 contains less than 40% by mass of metal from the metal hydrogen separation membrane, an advantageous weld can be formed between the metal core of the metal hydrogen separation membrane and / or the membrane itself (e.g., to which all layers are attached) and the metal connector, which is substantially free of cracks, inclusions, and voids. Therefore, the weld joint 130 can be produced using welding techniques that control the mass contribution of the metal from at least the metal core of the metal hydrogen separation membrane within the weld metal composition to a desired compositional level.

[0106] As previously explained, the integrity of the weld, and more specifically, whether or not the weld forms a substantially leak-free seal, can be affected by the final composition of the weld metal, particularly the final composition of the weld seal. The metal from the metal hydrogen separation membrane can include metals or metal alloys, and if it constitutes a substantial portion of the weld metal, its composition can have a detrimental effect on the composition of the weld metal. For example, when metal from a stainless steel-based connector is alloyed with stainless steel, the vanadium content of the vanadium-based metal hydrogen separation can produce weld metal with undesirable defect-forming properties. Since welding involves the melting (e.g., fusion) of two metal components, managing and optimizing the content of Group V metals (e.g., vanadium content) in the weld joint (e.g., to avoid cracking problems) can be a significant factor in forming a continuous leak-proof seal between these components. Therefore, it is preferable in this regard to reduce the mass contribution of the metal from the metal hydrogen separation membrane within the weld metal composition to, for example, less than 40% by mass of the metal core from the metal hydrogen separation membrane. It should be understood that 40% by mass of the metal can be considered as the average composition within the total mass of the weld metal of the weld joint seal.

[0107] However, in some instances, the properties of the weld metal can be improved with a smaller mass contribution from the metal core within the weld metal composition. Therefore, in some embodiments, the weld metal of the seal comprises less than 35% by mass of the metal core. In other embodiments, the weld metal of the seal comprises less than 30% by mass of the metal core. In still other embodiments, the weld metal of the seal comprises less than 25% by mass of the metal core. It should be understood that in some embodiments, the weld metal of the seal may include one of the following: less than 38% by mass, less than 34% by mass, less than 33% by mass, less than 31% by mass, less than 28% by mass, less than 23% by mass, or less than 20% by mass of the metal core.

[0108] As described in detail above, the weld joint 130 may also be produced with a substantially uniform composition over the entire volume of the sealing portion of the weld metal of the weld joint 130. Similarly, it should be understood that the sealing portion of the weld can be considered as part of the weld metal extending between the metal connector and at least the metal core of the metal hydrogen separation membrane, forming a continuous seal between the metal connector and at least the metal core of the metal hydrogen separation membrane. In many cases, the sealing portion may comprise the main portion of the weld metal of the weld joint 130. For example, as... Figure 3 As shown, the sealing part 131 of the weld (as shown) Figure 3 (As shown by the lighter dashed line) it occupies more than 80% of the weld metal. As shown, the seal 131 does not include... Figure 3The heel section 117A is shown. This heel section 117A includes an isolation section of the weld body at the bottom of the connecting section. Because this section is isolated from the majority of the weld metal body under the complete welding method / process, it can have a different composition. For example, the weld may include a heel, fingers, or other extensions that are isolated from the majority of the weld metal body under the complete welding method / process. In other words, the weld joint may include a weld body, which itself may include a sealing portion (e.g., a metal core that provides a sealing effect throughout the joint from the membrane to the connector and has less than 40% by mass of the metal core from the metal hydrogen separation membrane). The sealing portion may form the majority of the weld body. However, the weld body may include other portions within the weld body (e.g., non-sealing portions) that may or may not affect the seal, and in some cases may have a different composition.

[0109] Similarly, a “continuous seal” refers to a weld joint between the metal hydrogen separation membrane and the metal connector that connects the two components together using a weld joint that substantially prevents any gas (including any hydrogen inclusions therein) from passing through the weld joint and the connection formed between the metal hydrogen separation membrane and the metal connector by the weld joint. In this respect, a weld joint that substantially prevents any gas (including any hydrogen inclusions therein) from passing through the weld joint generally refers to a weld joint that maintains pressure when the membrane is internally pressurized to 10 bar N2. For example, in some embodiments, the weld joint can be tested to determine whether the weld joint maintains 10 bar N2 at room temperature for at least 12 hours, preferably at least 24 hours. It should be understood that room temperature refers to a temperature of 15-25°C. If applicable, a leak detection test can be used to detect leaks (see the description below of an example of such a test using a Swagelok liquid leak detector). In embodiments, the weld joint can provide a continuous, leak-free seal between the metal connector and at least the metal core of the metal hydrogen separation membrane. In this case, a “leak-free seal” should be understood to include a weld joint that substantially prevents any gas from passing through the weld joint. In practice, the leakage characteristics of a weld can be tested by pressure testing with a gas such as nitrogen (N2). In this sense, a leak-free weld or leak-free weld joint is a weld that has been kept at 10 bar N2 at room temperature for at least 12 hours. The leak-proof characteristics of a weld joint depend largely on the weld itself, which is continuous between the components around the joint interface and is also substantially free of defects, i.e., without cracks, inclusions, or voids that could allow gases (including hydrogen inclusions in these gases) to leak through.

[0110] In cases where compositional variations may exist in the weld metal, ideally, the weld metal of the sealing portion 131 should not contain a composition with more than 40% by mass of metal from the metal hydrogen separation membrane or isolation cavities as defined above for the desired mass percentage limitation. It should be noted that the weld may include small segments that may not have such a substantially uniform composition. In this sense, the sealing portion 131 of the weld metal (e.g., Figure 7 The shallow dashed section (in the text) can have a substantially uniform composition in the volume of the weld metal therein. In many instances, the substantially uniform composition of the sealing section will be within the body 217 section of the sealing portion 131. For example, regarding... Figure 7 As explained, the main body 217 of the weld metal of the sealing portion 131 can be the volume or mass of metal spaced apart from the periphery or edge of the weld joint, i.e., the internal portion of the volume of the weld metal of the weld joint. The peripheral and / or edge regions of the weld metal typically include a composition that transitions from the composition of the main body of the weld metal to the composition of the adjacent metal, and therefore may not conform to the substantially homogeneous composition of the main body of the weld metal. Similarly, the weld may also include isolation sections or portions, for example... Figure 3 The heel section 117A in the weld metal can have a different composition because this section is isolated from the majority of the main body 117 of the weld metal underwent by the complete welding method / process. The heel section 117A or any other similar isolation section does not form part of the main body 131 of the weld metal / weld, nor does it form part of the sealing portion 131 of the weld (e.g., any heel portion, etc., does not affect the sealing function of the weld).

[0111] This weld metal composition can be produced using a variety of welding techniques and procedures. It can be used to form... Figures 1-10 A welding process for the welded joint of configuration 100 shown includes the following methods.

[0112] Preparation of vanadium-based films:

[0113] A suitable vanadium-based film tube 110 is cut to a suitable length. The tube 110 shown may include an internal palladium coating but not an external coating. However, it should be understood that the method will equally apply to vanadium-based film tubes 110 without any internal palladium coating or vanadium-based film tubes 110 having coatings on their inner and outer sides. One or both ends of the vanadium-based film tube 110 may be square to form an end face 111A, which may be adapted to an end section 111 of the vanadium-based film 110 that overlaps with the abutment surface of the connector forming body 122 of the connector 120. Figure 2As shown, this can be achieved by clamping the vanadium-based film tube 110 in a jig 300, which holds the tube perpendicular to the working surface 302 of the planar grinding disk 304 (or other equivalent grinding configuration). However, other techniques are also possible. The jig 300 can then be held on the planar grinding disk 304, and the end face 111A can be ground until the end face 111A of the tube 110 is a right angle (square). Figure 1A , 2 (and 4). Right-angled edges advantageously provide a profile that is easy to process consistently, thereby improving reproducibility and repeatability.

[0114] Welding to form a joint / connection:

[0115] Prior to welding, an optional grinding step can be performed, wherein the end section 111, including the end face 111A of the tube 110, is ground by sanding to remove any oxides on the surface of the end region, thereby exposing vanadium to form a weld. The end section 111 of the vanadium-based film tube 110 can then be mounted above and on the inclined surface of the connector forming body 122 of the connector 120 (e.g., ...). Figure 1 As shown), the vanadium-based film tube 110 and the connector molded body 122 are in contact at the connection interface 132. Connector molded body 122 ( Figure 1 and 1A The tapered shape on the connector body 122 can be advantageously designed to allow for variations in both the diameter and thickness of the vanadium-based film tube 110. The tapered angle in the connector body 122 can range from 15° to 60° (e.g., 15° to 45° or 15° to 30°). This can facilitate the formation of a molten pool between the vanadium-based film tube 110 and the connector molded body 122. As will be explained in more detail below, forming a molten pool at this location allows other metallic materials (e.g., stainless steel) from the connector 120 to be melted into the molten pool, and thus helps to minimize the V concentration in the molten pool (and therefore minimize the associated risk of cracking). In the illustrated example, Approximately 30° Figure 1A However, it should be understood that, as mentioned above, other perspectives can be used.

[0116] The connection interface 132 can then be welded (e.g., laser welded) to join the vanadium-based membrane tube 110 to the connector 120. In embodiments, a self-welding fusion welding process can be used to form a self-welding weld at the weld joint 130, wherein the molten pool material is formed by materials in the connection joint region, such as vanadium and stainless steel, for the exemplary vanadium-based membrane tube 110 and stainless steel connector 120. This type of welding can have many useful advantages, such as enabling automation of the welding process. Additionally / alternatively, excluding filler wire and the resulting underfill weld profile can facilitate the design and use of mechanical restraints (chokes) on the weld joint, as described above and covered in the applicant's co-pending international patent application entitled "Arrangement for Joining and Sealing a Metallic Hydrogen Separation Membrane to a Metallic Connector," which claims priority to Australian Provisional Patent Application No. 2022901905, the contents of which should be understood to be incorporated herein by reference. However, it should be understood that other welding techniques can also be used. For example, in some embodiments, filler material may be used when desired or required.

[0117] Figure 3 The figure shows a cross-section of the finished welded joint 130. In this figure, dashed line 310 indicates the original shape of the vanadium-based film 110 before welding, and dashed line 312 indicates the original shape of the connector segment 122 of the stainless steel connector 120. Because the surface of the welded joint 130 is flush with or just below the surfaces of the vanadium-based film 110 and the stainless steel connector 120, the tightly fitting restraining collar 140 can slide on the welded joint 130. In other words, the specific configuration described allows the contour of the molten pool to be positioned within the outer diameter of the joint / film / connector (e.g., relatively recessed within the outer diameter). This allows for easy assembly of any configuration collar 140, etc., without unduly affecting or damaging the joint during use.

[0118] The weld joint 130 can be formed using any number of weld passes.

[0119] In some embodiments, the weld joint 130 can be formed in a single weld bead. In these embodiments, a tubular vanadium-based film 110 can be fused to the connector forming body 122 of the stainless steel connector / fitting 120 using a single weld bead, forming a molten pool composition 130B with an acceptable V level in the weld metal, which minimizes the risk of cracking. This can be achieved using a laser focus 155 (see, for example...). Figure 5(A)) is positioned away from the connection interface 132 and further positioned within the body of the stainless steel composition of the connector forming body 122. This positioning can be used to ensure that the molten pool from the laser beam substantially comprises the stainless steel from the connector 120.

[0120] In other embodiments, the weld joint can be formed in two weld passes, for example, following a process described in more detail below. In other embodiments, more than three weld passes can be used to achieve the desired continuous welding and weld composition.

[0121] An example of double-bead welding technology is Figures 4-7 The welded joint shown is an example of this technique, which includes:

[0122] First weld pass ( Figure 4 and Figure 6 This first weld bead can be used to fill the space at the connection interface 132 between the connector molded body 122 and the end 111A of the vanadium-based film 110 with a first weld bead composition. The first weld bead can also be used to fuse (e.g., fix in place) the tubular vanadium-based film 110 to the connector molded body 122 of the stainless steel connector / fitting 120. As described above, a tapered shape can be provided on the connector molded body, which will facilitate the formation of a molten pool between the connector molded body 122 and the end 111A of the vanadium-based film 110.

[0123] like Figure 6 As shown in (A) and 6(B), due to the small weld volume and high vanadium content, the first weld joint 130A may be prone to defects and associated weld cracking. Therefore, the first weld may be followed by:

[0124] ·Second weld pass ( Figure 5 and Figure 7 This process can be used to dilute the first weld bead composition of the molten pool 130 B with more stainless steel and to produce a substantially uniform weld metal composition in the sealing portion 131 of the weld metal 130, which forms a continuous seal between the vanadium-based film 110 and the connector molded body 122. This dilution aims to reduce the amount of V in the weld metal to an acceptable compositional level that minimizes the risk of cracking. The second weld bead can also be used to remelt the molten pool and thus help to distribute the metal more evenly throughout the molten pool, resulting in a more uniform composition through the sealing portion of the weld metal.

[0125] Various parameters can be varied to achieve the desired composition of the weld metal. For example, the focus and / or configuration of the laser beam can be varied between the first and second weld passes to help create this continuous seal between the vanadium-based film 110 and the connector molded body 122, and also to reduce the V level in the weld metal to an acceptable compositional level that minimizes the risk of cracking. This can be achieved, in practice, by aiming the molten pool more precisely at the connector material, i.e., further targeting the connector side of the connection interface during the second weld pass. Figure 4 and Figure 5 The image shows an example of parameters that can be changed between the first and second weld passes:

[0126] like Figure 4 As shown in (A), the first weld bead may have a focal point 150 located on the stainless steel of the connector interface 132. Figure 4 (A)) and has a tighter / narrower laser beam width BD1 than the second weld pass to generate a focused and deep-penetrating laser beam entering the focus 200. In this example, a smaller / narrower laser spot size can be used to heat the part, just enough to produce a melt. Heat is conducted outward from the center of the pool, so the center of the pool is hotter and its edges are cooler. The laser can be applied in various power forms. For example, as Figure 4 As shown in (B), the laser can be applied as a pulse 158 with an initial peak value, which decreases along the curve to reduce the applied laser power as the first weld pass proceeds. The weld joint 130A formed by this single weld pass can be used to fasten two components together, for example... Figure 6 The weld portion formed is shown in (A).

[0127] like Figure 5 As shown in (A), the second weld pass can be configured with a laser focus 155 ( Figure 5 (A) The laser focus is positioned further away from the connection interface 132 and further within the body of the stainless steel composition of the connector forming body 122. In other words, the method may include fixing the membrane / connector and then (as a second weld) controllably repositioning the laser in one direction, such that more connector material is heated and flows to the weld. In this example, the controllable movement is... Figure 4 The laser travels axially in the X direction as shown. The ease of controllable translation of the laser helps facilitate accurate and controllable composition of the molten pool. In this example, the focus 155 is in the X direction (see...). Figure 4(A) and 5(A)) move toward fitting 120, preferably at a distance of 1 / 2 increase in beam diameter / width, such that the edge of beam 150A on the vanadium tube side 110 remains identical for both the first and second weld passes. This positioning can be used to ensure that the molten pool from the laser beam substantially comprises the stainless steel from connector 120. Furthermore, in some instances, the second weld pass can also be configured with a wider laser beam width (wider spot size) compared to the first weld pass. A wider laser beam width can be used, for example, to better control the melting / dilution of the stainless steel and reduce the V content to a desired compositional amount (e.g., below 40 wt%). Additionally, the composition can be uniformly distributed throughout the molten pool or at least its sealing portion, which helps minimize the risk of cracking. As with the first weld pass, the laser can be applied in a variety of suitable power forms. Figure 5 An example is shown in (B) where the laser can be applied as a pulse 158A with constant laser power. The cross-section of the resulting welded joint is... Figure 7 As shown in (B).

[0128] In embodiments using this multi-pass welding method, repositioning the focus and using a wider beam size in the second pass can advantageously help homogenize the metal composition in the pool, thereby reducing the V content and helping to reduce defects compared to the first pass. In this sense, the composition of the weld metal in the weld joint becomes substantially more homogeneous throughout the entire weld metal volume. While not wishing to be limited to any one theory, a smaller laser beam size produces a higher energy concentration over the area irradiated by the beam compared to a wider beam. Furthermore, the cross-section of the laser beam is circular. Therefore, during the rotation of the connector and the membrane during welding, the material at the center of the beam receives more energy than at the edges. Heat is conducted outward from the center of the molten pool, so the molten pool is hotter at the center and cooler at its edges. Therefore, moving the focus toward the connector and using a wider beam ensures that the most energy in the second pass is directed to the material of the connector 120, thereby ensuring that more of that material is melted in the molten pool compared to the vanadium membrane 110.

[0129] It should be understood that, through Figure 3 The optical microscope image of the cross-section of the weld joint shown reveals a grain structure, indicating a substantially uniform composition of the weld metal throughout the entire volume of the weld metal sealing portion 131. This weld is produced using a second weld pass, for example, as... Figure 5 and Figure 7 As shown. Figure 3 The optical microscope images show a substantially uniform grain structure across the entire cross-section of the weld, particularly within the body of the seal 131 of the weld metal. The body of the seal 131 (i.e., the volume or mass of the metal spaced apart from the periphery or edge of the weld joint) has a substantially uniform composition throughout its entire volume.

[0130] Figure 6 and Figure 7 The difference in compositional characteristics (vanadium (V) and iron (Fe)) across the molten pool is shown in another example of a two-pass weld method following an embodiment of the present invention, obtained from an energy dispersive spectroscopy (EDS) line scan. The first and second passes follow a welding procedure similar to that described in Example 1. Note that in Figure 6 and Figure 7 In this data, the data was not filtered or scaled based on the assumption of a pure vanadium tube composition; therefore, the vanadium mass percentage was not scaled to 100%, but rather to 80%. This data will be compared with... Figures 10-13 The data was compared, with the latter assuming the vanadium tubes were pure and used to scale / reference the vanadium concentration to 100%.

[0131] Figure 6 Provided (a) EDS line scan analysis of the weld portion after only the first weld pass (elemental composition shown as mass %) Figure 6 (b) Line 210 depicts the EDS line scan path. This shows the heterogeneous composition within the weld metal, where the vanadium content through the weld ranges from 62.5% by mass to 27% by mass. For the first weld pass only, the composition of the weld metal of the seal 130A can have regions with high vanadium content, which can create areas where cracks may exist in the molten pool (see, for example, [link to previous section]). Figure 6 (b) shows the crack. As mentioned above, it is generally preferred that the vanadium content is less than 40% by weight, more preferably less than 35% by weight. For stainless steel and Inconel, it is generally preferred that the vanadium content is less than 35% by weight to avoid cracking. Figure 6 The corresponding SEM image of the weld section in (b) shows that this change in vanadium content creates areas of excessive vanadium content in the weld metal, which leads to cracks (e.g., crack 220).

[0132] Figure 7 (a) EDS line scan analysis (elemental composition shown as mass %) is provided, and line 215 in Figure (b) depicts the EDS line scan path of the weld pool, showing that the vanadium content in the weld metal seal is substantially reduced to below 20% by mass and remains substantially constant throughout the weld metal. The composition of iron and vanadium is substantially homogeneous in the weld metal seal. Figure 7 As can be seen in (A), the main body 217 of the welded metal (made of...) Figure 7 The dashed line in (A) indicates that the volume or mass of the metal spaced apart from the periphery or edge of the weld joint has a substantially homogeneous composition throughout its entire volume. As stated above regarding... Figure 3 The weld shown may also include an isolation section, as indicated by the weld portion. Figure 3The heel section 217A, being isolated from the majority of the body 217 of the seal 131 of the weld metal 130 by the complete welding method / process, can have a different composition. The heel section 217A does not form part of the seal 131. In this case, the heel section 217A is in a position where it has not properly undergone the second weld pass, thus affecting the final composition of the metal in this section. However, the corresponding SEM image of the weld section shows no obvious cracks in the weld metal of the seal 131.

[0133] Many suitable welding configurations and equipment can be used to form the weld joints described above. One example of a laser welding machine 200 that can be used to form the weld joints described above is... Figure 8 and Figure 9 As shown in the image. Figure 8 It shows the method for generating Figure 3 , Figure 6 and Figure 7 The laser welding machine 200 shown is an Alpha ALW 200 enclosed laser welding unit (manufactured by Alphalaser, Germany) that includes a fourth-stage laser (pulsed Nd:YAG laser). The laser welding machine 200 includes an improved protective structure surrounding the laser to accommodate a 1.1m long membrane. Although not shown, a custom-designed radiation shield with port holes is designed to replace one of the laser welding machine doors. The custom shield incorporates existing laser welding machine safety interlocks that prevent laser operation if the shielding door is opened. The laser welding machine 200 can be used to form self-fusion welds after a computer-controlled automated welding program using the welding process.

[0134] Figure 9 An example of a clamping assembly 250 is shown, which can be used to hold the tubular vanadium-based film 110 and the connector 120 for use in a laser welding machine 200. Figure 8The automated laser welding operation is described. However, it should be understood that other configurations can also be used. The fixture assembly 250 shown includes a tailstock 280 mounted on a linear track 282, configured to hold a connector 120 concentric with a tubular vanadium-based film 110 mounted in a rotating chuck 270. The chuck 270 may include copper jaws 272 that grip the film 110 and serve as heat sinks. The position of the tailstock 280 can be controlled via a computer that also uses a suitable software interface to control and drive the laser welding machine, such as a computer running a custom LabVIEW program interface. The tailstock 280 can be moved along the track 282 by a motor 284 that drives a threaded rod 286 connected to the tailstock 280. The fixture assembly 250 can be mounted on a movable bed 290 of the laser welding machine 200. The laser welding machine 200 may also include a shielding gas nozzle 260 for delivering shielding gas to the welding area during welding.

[0135] In use, connector 120 can be screwed into tailstock 280, wherein connector interface 122 extends outward to mate with the tubular vanadium-based film 110 prepared for welding before being moved to the welding position. Once the tubular vanadium-based film 110 to be welded and connector 120 are mated and positioned, laser welding of the connection interface 132 can be performed. Laser welding machine 200 can be operated to perform desired welding processes, such as the aforementioned single-pass or double-pass processes as an automated process. This automation helps ensure the consistency and repeatability of welding, minimizing variations from human / operator factors.

[0136] When forming the hydrogen separation membrane, connectors are preferably welded to each end of the membrane. Once welding is completed at both ends of the membrane, quality assurance / control (QA / QC) can be performed to check the quality of these seals using a two-stage leak test on each membrane. Leak testing of individual membranes (also known as "snoop" testing) can be performed on some or, in some cases, all membranes produced and sampled. This can be done at any time, but it may be advantageous to perform snoop testing close to the welding process or, in some cases, immediately after the welding process. To perform snoop testing, the membrane that has undergone laser welding is given a temporary O-ring (not shown) and internally pressurized to 10 bar N2; then, the welded seals and membranes are tested individually using a Swagelok snoop tester, where leaks in the seals and vanadium tubes can be detected by visible bubbling at the defect site. Various snoop test configurations / devices are possible. In some forms, the snoop test device (not shown) allows the membrane to rotate freely under pressure, making it possible to check the weld quality.

[0137] It should also be understood that the tubular membrane using the aforementioned welded joint can be incorporated into a tubular catalytic membrane reactor (CMR), as taught again in, for example, U.S. Patent No. 10,590,516, the contents of which should be understood to be incorporated herein by reference. As explained in US10,590,516, a CMR with a tubular membrane can be used to selectively extract hydrogen from a hydrogen-containing gas (e.g., syngas) to produce raffinate (lean H2 syngas) and H2 permeate.

[0138] Example

[0139] Example 1 - Laser welding of 3 / 8” vanadium tube to stainless steel fittings

[0140] Use targeting Figures 8-9 The laser welding system and fixture shown and described include a laser welding machine 200 (Alpha ALW 200 enclosed laser welding apparatus with a pulsed Nd:YAG laser) for welding 3 / 8” vanadium pipes to stainless steel fittings using the double-pass welding technique described above.

[0141] Materials

[0142] Use the following materials to form welded joints.

[0143] Vanadium tube: outer diameter (OD) is 9.52 mm (3 / 8), wall thickness (WT) is 0.25-0.28 mm; edges are ground to right angles and the surface is scraped to remove oxides.

[0144] • Stainless steel fittings: 9.52 mm (3 / 8) diameter, with a 30° bevel from the horizontal plane. Figure 4 Angle in (A)) ). Surface scraping to remove the oxide layer.

[0145] To form a joint before laser welding, the vanadium tube is forced against a stainless steel fitting to form a single V-joint assembly, such as... Figure 4 As shown in (A).

[0146] Welding parameters

[0147] Then, the weld joint is formed using the double-pass welding procedure described above. For this weld, the following parameters are used:

[0148] 1. First weld pass:

[0149] Relative to the edge of the vanadium tube (x=0, y=0) (see...) Figure 4 Laser focus at edge 111B) in (A): x = 0.12 mm, y = 0.0 mm

[0150] Laser parameters: 210 V, 3ms pulse duration, 35Hz, 0.6 mm beam diameter

[0151] Pulse shape: such as Figure 4 (B) shows

[0152] Power: 51.1 W

[0153] Rotation speed: 3 rpm

[0154] Protective gas: Ar, 5 L / min

[0155] The weld obtained from the first weld pass is in Figure 10 As shown in the figure. The reference numerals follow the conventions for... Figure 6 The accompanying figure references are enclosed in 200.

[0156] 2. Second weld pass:

[0157] Relative to the edge of the vanadium tube (x=0, y=0) (see...) Figure 4 Laser focus at edge 111 in (A) and (B): x = 0.22 mm, y = 0.2 mm

[0158] Laser parameters: 210 V, 3.4 ms pulse duration, 35 Hz, 0.8 mm beam diameter

[0159] Pulse shape: such as Figure 5 (B) shows

[0160] Power: 81.6 W

[0161] Rotation speed: 3 rpm

[0162] Protective gas: Ar, 5 L / min

[0163] The weld obtained from the second weld pass is Figure 11 As shown in the figure. The reference numerals follow the conventions for... Figure 7 The accompanying figure references are enclosed in 200. Note that... Figure 10 The weld dilution line scans presented in (A) and 11(A) were analyzed via energy-dispersive spectroscopy (EDS). Since EDS is a spectroscopic technique, any quantitative analysis must be properly calibrated. Because this is not always possible, the use of vanadium tubes is purely an assumption for scaling / reference data. Therefore, it should be understood that the iron concentration in all results is not an exact measurement of concentration, but rather can be used as a relative reference tool, and the vanadium concentration is the only valid concentration measurement.

[0164] and Figure 6 and Figure 7 Similar to the example shown, compare EDS ( Figure 10 (A) and Figure 11(A) SEM image along the EDS line scanning path ( Figure 10 (B) and Figure 11 (B)) and the first weld bead ( Figure 10 ) and second weld ( Figure 11 SEM image ( Figure 10 (C) and Figure 11 (C) shows that the first weld bead exhibits an uneven composition within the weld metal, with the vanadium content in the weld portion ranging from 45% to 20% by mass. Following the first weld bead, the weld metal composition of the weld joint 330A exhibits a region with a high vanadium content, which can create areas of potential cracking in the molten pool (see example...). Figure 10 Cracks (B and C) are shown in the diagram. In contrast, the second weld bead ( Figure 11 ) with EDS scanning ( Figure 11 (A) shows that the vanadium content in the weld metal is significantly reduced to below 20% by mass and remains substantially constant throughout the weld metal. The composition of iron and vanadium is substantially uniform in the weld metal, and particularly in the sealing portion 331 of the weld metal 330. Figure 11 The main body 417 of the weld metal 330 contains iron and vanadium. The composition of iron and vanadium in the weld metal 330 can be substantially uniform. The main body 417 of the sealing portion 331 of the weld metal 330 (the metal volume or mass spaced apart from the periphery or edge of the weld joint, such as...) Figure 11 (As shown by the dashed line) has a substantially uniform composition throughout its entire volume. Furthermore, the corresponding SEM image ( Figure 11A (C) shows that there are no obvious cracks in the weld metal 330 of the sealing part 331.

[0165] Figure 11 SEM backscattered electron images (AsB) are provided, showing the grain structure of the weld joint between the vanadium film tube and the stainless steel connector after the second weld bead, which has been used with... Figure 11A The welding joint shown is formed using a similar procedure. Figure 11 This welding technique has been confirmed to produce a substantially uniform composition, particularly in the sealing portion 331 of the weld metal 330. Figure 11A In the main body 417 of the sample, backscattered electron imaging reveals compositional differences (differences in average atomic number). Leak check In the image shown, vanadium 310 is shown as a black shading, stainless steel 320 is a lighter shading than vanadium 310, and the molten pool / metal 330 has a gray shading between vanadium and stainless steel. The substantially uniform gray shading in the weld metal 330 suggests / supports the claim that the elemental composition is substantially uniform across the entire cross-section of the weld metal, particularly within the bulk of the weld metal 330.

[0166] Figures 8-9

[0167] As described above, the welds are inspected using a 100% visual test. This involves sealing the ends of the vanadium tube and stainless steel connector, performing a pressure test of 10 bar N2 at room temperature, and visually inspecting for leaks using a leak detection fluid (Swagelok monitoring liquid leak detector).

[0168] Example 2 - Laser welding of 3 / 8” vanadium tube to Inconel 600 fittings

[0169] Use targeting Materials The laser welding system and fixture shown and described include a laser welding machine 200 (Alpha ALW 200 enclosed laser welding apparatus with a pulsed Nd:YAG laser) for welding 3 / 8” vanadium tubes to Inconel 600 fittings using the double-pass welding technique described above.

[0170] Figure 4

[0171] Use the following materials to form welded joints.

[0172] Vanadium tube: outer diameter (OD) is 9.52 mm (3 / 8), wall thickness (WT) is 0.25-0.28 mm; edges are ground to right angles and the surface is scraped to remove oxides.

[0173] • Inconel Nickel 600 fittings: 9.52 mm (3 / 8) diameter, 30° chamfer from the horizontal plane. Figure 4 Angle in (A)) ). Surface scraping to remove the oxide layer.

[0174] Note INCONEL® (Nickel-Chromium-Iron) Alloy 600 (UNS N06600 / W.Nr. 2.4816). To form a joint prior to laser welding, the vanadium tube is forced against the INCONEL Nickel 600 fitting to form a single V-joint assembly, as shown below. Welding parameters As shown in (A).

[0175] Figure 4

[0176] Then, the weld joint is formed using the double-pass welding procedure described above. For this weld, the following parameters are used:

[0177] 1. First weld pass:

[0178] Relative to the edge of the vanadium tube (x=0, y=0) (see...) Figure 4 Laser focus at edge 111B) in (A): x = 0.12 mm, y = 0.0 mm

[0179] Laser parameters: 210 V, 3ms pulse duration, 35Hz, 0.6 mm beam diameter

[0180] Pulse shape: such as Figure 12 (B) shows

[0181] Power: 51.1 W

[0182] Rotation speed: 3 rpm

[0183] Protective gas: Ar, 5 L / min

[0184] The weld obtained from the first weld pass is in Figure 6 As shown in the figure. The reference numerals follow the conventions for... Figure 12 The accompanying figure references are enclosed in 400. Also, it should be noted that... Figure 4 The weld dilution line scans presented in (A) and 13(A) were analyzed via energy-dispersive spectroscopy (EDS). Since EDS is a spectroscopic technique, any quantitative analysis must be properly calibrated. Because this is not possible, the use of vanadium tubes is purely an assumption for scaling / reference data. Therefore, it should be understood that the iron concentration in all results is not an exact measurement of concentration, but rather can be used as a relative reference tool, and the vanadium concentration is the only valid concentration measurement.

[0185] 2. Second weld pass:

[0186] Relative to the edge of the vanadium tube (x=0, y=0) (see...) Figure 5 Laser focus at edge 111 in (A) and (B): x = 0.22 mm, y = 0.2 mm

[0187] Laser parameters: 210 V, 3.4 ms pulse duration, 35 Hz, 0.8 mm beam diameter

[0188] Pulse shape: such as Figure 13 (B) shows

[0189] Power: 81.6 W

[0190] Rotation speed: 3 rpm

[0191] Protective gas: Ar, 5 L / min

[0192] The weld obtained from the second weld pass is Figure 7 As shown in the figure. The reference numerals follow the conventions for... Figure 12 The accompanying figures are labeled with 400.

[0193] Similar to Example 1, when comparing EDS ( Figure 12 (A) and 13(A)), SEM images along the EDS line scan path ( Figure 12(B) and 13(B)) and the first weld bead welding ( Figure 12 SEM image of the second weld pass (Figure 14) Figure 12 In (C) and 13(C)), it can be seen that the first weld bead exhibits an uneven composition within the weld metal, with the vanadium content in the weld portion ranging from 70% to 20% by mass. Following the first weld bead, the weld metal of the weld joint 530A exhibits a large area with high vanadium content, which can create areas with significant cracking in the molten pool (see example...). Figure 13 Cracks (B and C) are shown in the diagram. In contrast, the second weld bead ( Figure 13 ) with EDS scanning ( Figure 13 (A) shows the vanadium content in the weld metal 530, particularly the sealing portion 531 of the weld metal 530. Figure 13 The vanadium content in the main body 617 of the weld metal is significantly reduced to below 35% by mass and remains substantially constant throughout the weld metal. The composition of nickel and vanadium is substantially uniform in the weld metal. The composition of nickel and vanadium can be substantially uniform in the weld metal. The main body 617 of the sealing portion 531 of the weld metal 330 (the metal volume or mass spaced apart from the periphery or edge of the weld joint, such as...) Figure 13 (As shown by the dashed line in the image) has a substantially uniform composition throughout its entire volume. Furthermore, the corresponding SEM image (… Figure 13A (C) shows that there are no obvious cracks in the weld metal of weld joint 530.

[0194] Figure 13 SEM backscattered image (AsB) is provided, showing the grain structure of the weld joint between the vanadium film tube and the Incol Nickel 600 connector after the second weld bead, which has been used with... Figure 13A The welding joint shown is formed using a similar procedure. Figure 13 This welding technique has been confirmed to produce a substantially uniform composition, particularly at the sealing portion 531 of the weld metal 530. Figure 13A Within the main body 617 of the sample. Backscattered electron imaging reveals compositional differences (differences in average atomic number) within the sample. Leak check In the image shown, vanadium 510 is shown as a black shade, nickel (of Inconel 520) is shaded lighter than vanadium 510, and the molten pool / metal 530 has a gray shade between vanadium and nickel. The substantially uniform gray shade in the weld metal 530 suggests / supports the claim that the elemental composition is substantially uniform across the entire cross-section of the weld metal, particularly within the bulk of the weld metal 530.

[0195] ​

[0196] As described above, the solder joints were inspected using a 100% visual test. This involved sealing the ends of the vanadium tube and the Inconel 600 connector, performing a 10 bar N2 pressure test at room temperature, and visually inspecting for leaks using a leak detection fluid (Swagelok monitoring liquid leak detector).

[0197] In the context of this specification (including the claims), the terms “comprise,” “comprises,” “comprised,” or “comprising” are used, they should be interpreted as specifying the presence of the stated feature, integer, step, or component, but do not preclude the presence of one or more other features, integers, steps, components, or groups thereof.

[0198] It should be understood that the term "substantially" means that the state or parameter may not be 100%, but it can approach or be used to be mostly 100%. Therefore, "substantially" can be understood as meaning that the state or parameter is a large or significant degree of that state or parameter. "Substantially" can also be understood as meaning that the state or parameter is largely that state or parameter. "Substantially" can also be understood as meaning that the state or parameter is mostly that state or parameter, and / or substantially that state or parameter. In other words, "substantially" means that the parameter approximates the perfect state of that parameter or state, but may not be the perfect form of that parameter or state.

Claims

1. A weld joint between a metal connector and at least a metal core of a metal hydrogen separation membrane, the weld joint comprising a fusion weld portion formed by the metal connector and at least the metal core of the metal hydrogen separation membrane and between the two. The connector is formed of a metal or metal alloy different from the metal core of the hydrogen separation membrane, and The welded portion includes a sealing portion that provides a continuous seal between the metal connector and at least the metal core of the metal hydrogen separation membrane, the sealing portion having a weld metal composition comprising less than 40% by mass of metal from the metal core of the metal hydrogen separation membrane.

2. The welded joint as described in claim 1, wherein, The weld metal of the sealing part has a substantially uniform composition throughout the entire volume of the weld metal.

3. The welded joint as described in claim 1 or 2, wherein, The sealing portion contains at least 80% of the weld metal, preferably 80% to 100% of the weld metal.

4. The welded joint as described in claim 1, 2, or 3, wherein, The weld metal of the sealing portion comprises at least one of the following: Less than 35% by mass of the metal from the metal core of the metal hydrogen separation membrane; Less than 30% by mass of the metal from the metal core of the metal hydrogen separation membrane; Less than 25% by mass of the metal from the metal core of the metal hydrogen separation membrane.

5. The welded joint as claimed in any of the preceding claims, wherein, The volume composition of the weld metal in the sealing portion does not contain more than 40% by mass of the metal core from the metal hydrogen separation membrane, preferably no more than 35% by mass of the metal core from the metal hydrogen separation membrane.

6. The welded joint as claimed in any of the preceding claims, wherein, The connector may be made of at least one of the following: steel, stainless steel, nickel-chromium-iron alloy, brass, Inco nickel, Incoloy, or a combination thereof.

7. The welded joint as claimed in any of the preceding claims, wherein, At least the metal core of the hydrogen separation membrane comprises a metal or metal alloy based on Group V, preferably vanadium, tantalum or niobium metal or metal alloy, more preferably vanadium or vanadium alloy.

8. The welded joint as claimed in any of the preceding claims, wherein, The metal core comprises a non-porous body, preferably a non-porous tube.

9. The welded joint as claimed in any of the preceding claims, wherein, The metal core and the hydrogen separation membrane are tubular, and the connector is also tubular.

10. The welded joint as claimed in any of the preceding claims, wherein, The welded joints include laser welding connections, electron beam welding connections, or electric arc welding connections.

11. The welded joint as claimed in any of the preceding claims, wherein, The welded joint includes a self-fusion weld section.

12. The welded joint as claimed in any of the preceding claims, wherein, The metal core of the hydrogen separation membrane is mounted on or against the connector body of the connector, the metal core and the connector body are in contact at a connection interface, in which the end face of the metal core is close to, substantially adjacent to or overlaps with the adjacent face of the connector body; and the welding joint connects at least the metal core of the hydrogen separation membrane and the connector around the connection interface.

13. The welded joint of claim 12, comprising a continuous weld portion extending circumferentially around and above the connection interface.

14. The welded joint as claimed in claim 12 or 13, wherein, At least the end face of the metal core of the hydrogen separation membrane at the connection interface includes substantially right-angled edges.

15. The welded joint as claimed in claim 12, 13 or 14, wherein, The connector body includes tapered, beveled, or chamfered sections configured to receive the end section of the metal core of the hydrogen separation membrane thereon.

16. The welded joint as claimed in claim 15, wherein, The connector body includes a tapered surface having a taper angle of 15° to 60°, preferably 15° to 45°, more preferably 15° to 30°, and even more preferably about 30°.

17. A method for bonding and sealing at least a metal core of a hydrogen separation membrane to a metal connector, the method comprising: At least the end section of the metal core of the metal hydrogen separation membrane is mounted on or abuts against the connector body of the metal connector, the connector being formed of a metal or metal alloy different from the metal core of the hydrogen separation membrane, the metal core and the connector body contacting each other at a connection interface, in which the end face of at least the metal core of the hydrogen separation membrane is close to, substantially adjacent to or overlaps with the adjacent face of the connector body; At least the metal core of the hydrogen separation membrane is welded to the connector to form a welded joint at and above the connection interface. The welded joint includes a fusion weld portion, which includes a sealing portion that provides a continuous seal between the metal connector and at least the metal core of the metal hydrogen separation membrane. The sealing portion has a weld metal composition comprising less than 40% by mass of metal from the metal core of the metal hydrogen separation membrane. This forms a continuous weld seal between the metal connector and at least the metal core of the metal hydrogen separation membrane.

18. The method of claim 17, wherein the welded joint of any one of claims 1 to 16 is used.

19. The method of claim 17 or 18, wherein, The weld metal of the sealing portion has a substantially uniform composition throughout the entire volume of the weld metal.

20. The method of claim 17, 18 or 19, wherein, The sealing portion contains at least 80% of the weld metal, preferably 80% to 100% of the weld metal.

21. The method according to any one of claims 17 to 20, wherein, The weld metal of the sealing portion includes at least one of the following: Less than 35% by mass of the metal from the metal core of the metal hydrogen separation membrane; Less than 30% by mass of the metal from the metal core of the metal hydrogen separation membrane; or Less than 25% by mass of the metal from the metal core of the metal hydrogen separation membrane.

22. The method according to any one of claims 17 to 21, wherein, The volume composition of the weld metal in the sealing portion does not contain more than 40% by mass of the metal core from the metal hydrogen separation membrane, preferably no more than 35% by mass of the metal core from the metal hydrogen separation membrane.

23. The method according to any one of claims 17 to 22, wherein, The welded joint is formed by at least one of laser welding, electron beam welding or arc welding.

24. The method according to any one of claims 17 to 23, wherein, The weld joint is formed using at least one continuous weld bead at, around, or near the connection interface.

25. The method according to any one of claims 17 to 24, wherein, The weld joint is formed using at least two weld passes, such as continuous weld passes, at, around, or near the connection interface.

26. The method of claim 25, wherein, The at least two weld passes include: A first weld bead, wherein the first weld bead forms a first weld bead composition between at least the metal core of the hydrogen separation membrane and the connector; and The second weld bead dilutes the first weld bead composition with more metal from the connector to reduce the metal composition of the weld metal of the seal portion from the metal core of the hydrogen separation membrane to less than 40% by mass of the metal from the metal core.

27. The method of claim 26, wherein, The first weld essentially fuses at least the metal core of the hydrogen separation membrane to the connector.

28. The method of claim 25, 26 or 27, wherein, The at least two weld passes include a laser weld pass using a laser beam, and wherein the laser beam width used in the second weld pass is wider than the laser beam width of the first weld pass.

29. The method according to any one of claims 17 to 28, wherein, The connector is made of at least one of the following: steel, stainless steel, nickel-chromium-iron alloy, brass, Inco nickel, Incoloy, or a combination thereof.

30. The method according to any one of claims 17 to 29, wherein, The metal core of the hydrogen separation membrane comprises a metal or metal alloy based on Group V, preferably vanadium, tantalum or niobium metal or metal alloy, more preferably vanadium or vanadium alloy.

31. The method according to any one of claims 17 to 30, wherein, The welded joint includes a continuous weld portion that surrounds the connection interface and extends circumferentially above the connection interface.

32. A hydrogen separation membrane system comprising a hydrogen separation membrane joined and sealed to a connector molded body using a welded joint as described in any one of claims 1 to 16.

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