Hydrogen conveying flexible pipeline and hydrogen leakage detection method

Abstract

The invention relates to a hydrogen transport flexible pipeline and a hydrogen leakage detection method, the hydrogen transport flexible pipeline comprises a lining layer, an airtight layer, a fiber reinforced layer and an outer protective layer, the lining layer, the airtight layer, the fiber reinforced layer and the outer protective layer are all cylinder structures, the lining layer is made of a non-metal thermoplastic resin material, and the outer protective layer is made of a non-metal thermoplastic resin material. The airtight layer is composed of a graphene / aluminum oxide hydrogen-resistant coating and a metal aluminum layer, the fiber-reinforced layer is made of a non-metal high-strength fiber composite material, the outer protective layer is made of a non-metal thermoplastic resin material, and the fiber-reinforced layer comprises a fiber-reinforced inner layer and a fiber-reinforced outer layer; an airtight layer is wound on the outer side of the lining layer, a fiber reinforced inner layer is wound on the outer side of the airtight layer in the forward direction, a fiber reinforced outer layer is wound on the outer side of the fiber reinforced inner layer in the reverse direction, and an outer protection layer is arranged on the outer side of the fiber reinforced outer layer; a monitoring element is arranged in the outer protection layer and used for monitoring the hydrogen concentration change or the resistance change of the outer protection layer in real time, and the hydrogen protection device can be widely applied to the technical field of new energy development.

Description

Technical Field

[0001] The present invention relates to the technical field of new energy development, and in particular to a flexible hydrogen transmission pipeline and a hydrogen leakage detection method. Background Art

[0002] As the limitations and environmental pollution of traditional energy sources become increasingly severe, hydrogen energy, as a clean energy source, has gradually become a focus of attention worldwide. Hydrogen production from offshore wind power, in particular, has attracted widespread attention. Pipeline hydrogen transportation is gaining widespread attention as a solution to the high transportation costs associated with hydrogen energy development and large-scale applications. Pipeline hydrogen transportation primarily occurs in high-pressure gas or liquid form, enabling long-distance, large-scale transportation through hydrogen blending and co-transportation of hydrogen and oil.

[0003] However, conventional steel pipelines face high construction costs and hydrogen embrittlement, leading to the widespread adoption of thermoplastic reinforced flexible pipe (RTP) as a superior transportation method. These pipes typically consist of an inner liner, a reinforcement layer, and an outer protective layer. These non-metallic pipes offer both excellent flexibility and corrosion resistance. However, when used directly for hydrogen transportation, these pipes can suffer from excessive hydrogen permeability. Summary of the Invention

[0004] In view of the above problems, the purpose of the present invention is to provide a hydrogen transmission flexible pipeline and a hydrogen leakage detection method, which can solve the problem of excessively high hydrogen permeability of thermoplastic reinforced layer flexible pipelines when transporting hydrogen.

[0005] To achieve the above objectives, the present invention adopts the following technical solutions: On the one hand, a flexible hydrogen transmission pipeline is provided, comprising an inner liner, an airtight layer, a fiber-reinforced layer, and an outer protective layer, wherein the inner liner, the airtight layer, the fiber-reinforced layer, and the outer protective layer are all cylindrical structures, the inner liner is made of a non-metallic thermoplastic resin material, the airtight layer is composed of a graphene / alumina hydrogen barrier coating and a metal aluminum layer, the fiber-reinforced layer is made of a non-metallic high-strength fiber composite material, the outer protective layer is made of a non-metallic thermoplastic resin material, and the fiber-reinforced layer includes a fiber-reinforced inner layer and a fiber-reinforced outer layer; The airtight layer is wound around the outer side of the inner lining layer, the fiber reinforced inner layer is wound forwardly around the outer side of the airtight layer, the fiber reinforced outer layer is wound backwardly around the outer side of the fiber reinforced inner layer, and the outer protective layer is arranged on the outer side of the fiber reinforced outer layer; A monitoring element is provided in the outer protective layer, and the monitoring element is used to monitor the change of hydrogen concentration or the change of resistance of the outer protective layer in real time, so that an external host computer can judge the hydrogen leakage of the hydrogen transmission flexible pipeline based on the change of hydrogen concentration or the change of resistance of the outer protective layer.

[0006] Furthermore, the airtight layer is provided on the inner lining layer of the cylindrical structure by a winding process, and the specific process is as follows: Add a first adhesive to the outside of the inner liner, and use an extrusion process to add EVOH material between the inner liner and the first adhesive aluminum layer; Adding a second adhesive to the outside of the EVOH material to prepare the EVOH barrier film; An aluminum strip is spirally wound around the outside of the EVOH barrier film in a forward direction for one circle, and the wound aluminum strips are combined into a first bonding aluminum layer; or a plurality of aluminum strips are longitudinally arranged around the outside of the EVOH barrier film for one circle, and the arranged aluminum strips are combined into a first bonding aluminum layer; On the outer side of the first bonding aluminum layer, an aluminum strip is spirally wound in the opposite direction for a second layer, and the wound aluminum strips are combined into a second bonding aluminum layer; Using a cooling system to process and fix the first bonding aluminum layer and the second bonding aluminum layer into shape; Attaching a graphene / aluminum oxide hydrogen barrier coating on the outer surface of the second bonding aluminum layer; During the preparation process, the thickness of the graphene / aluminum oxide hydrogen barrier coating is controlled by controlling the number of spraying times.

[0007] Furthermore, the graphene / aluminum oxide hydrogen barrier coating is prepared by a CVD combined transfer method or a spraying method.

[0008] Furthermore, the ply angle of the aluminum strips in the first bonding aluminum layer that are spirally wound in the forward direction is 55°, and the ply angle of the aluminum strips in the second bonding aluminum layer that are spirally wound in the reverse direction is -55°.

[0009] Furthermore, the winding angle of the fiber-reinforced inner layer is 55°, and the winding angle of the fiber-reinforced outer layer is -55°.

[0010] Furthermore, the outer protective layer includes an outer protective layer outer wall, an outer protective layer inner wall and the monitoring element; The outer wall of the outer protective layer and the inner wall of the outer protective layer are both cylindrical structures, and the monitoring element is embedded in the cavity between the outer wall of the outer protective layer and the inner wall of the outer protective layer.

[0011] Furthermore, the monitoring element adopts a LiAlD2 monitoring element, which is used to monitor the resistance change of the outer protective layer in real time and is connected to a host computer through an electrical contact.

[0012] Furthermore, the optical fiber hydrogen sensor based on palladium-modified hexagonal boron nitride embedded in the spiral winding is integrated in the cavity between the outer wall of the outer protective layer and the inner wall of the outer protective layer, and is used to monitor hydrogen leakage in real time and transmit it to the host computer via optical signals.

[0013] In another aspect, a method for detecting a hydrogen leak is provided, comprising: Make flexible hydrogen transmission pipelines; Install the hydrogen transmission flexible pipeline at the location where it is required to serve; During the service life of the hydrogen transmission flexible pipeline, leaked hydrogen comes into contact with the monitoring element embedded in the outer protective layer. The monitoring element monitors the changes in hydrogen concentration or resistance of the outer protective layer in real time and sends the information to the host computer. The host computer determines the hydrogen leakage of the hydrogen transmission flexible pipeline based on the change of hydrogen concentration or the resistance change of the outer protective layer.

[0014] Furthermore, during the service of the hydrogen transmission flexible pipeline, leaked hydrogen contacts a monitoring element embedded in the outer protective layer. The monitoring element monitors the change in hydrogen concentration or the change in resistance of the outer protective layer in real time and sends the information to a host computer, including: When the monitoring element uses a LiAlD2 monitoring element, the leaked hydrogen is adsorbed by the LiAlD2 monitoring element, causing its resistance to change. The more hydrogen the LiAlD2 monitoring element adsorbs, the greater its resistance. The LiAlD2 monitoring element is connected to the host computer through electrical contacts, and the resistance change of the outer protective layer is sent to the host computer; When the monitoring element uses a fiber optic hydrogen sensor based on palladium-modified hexagonal boron nitride, the fiber optic hydrogen sensor monitors the changes in hydrogen concentration in real time and transmits the real-time monitoring data to the host computer through optical signals.

[0015] The present invention has the following advantages due to the adoption of the above technical solution: 1. The airtight layer of the present invention is made by longitudinally winding and spirally winding an aluminum layer, which reduces the hydrogen leakage coefficient of the pipeline during service in a hydrogen environment. In addition, a graphene / alumina hydrogen barrier coating is used on the aluminum layer, which simplifies the manufacturing process and can further improve the hydrogen barrier performance of the pipeline.

[0016] 2. The overall material of the present invention is composed of non-metallic materials. The fiber material of the inner lining layer has excellent chemical resistance and corrosion resistance, ensuring that the part in contact with hydrogen will not undergo chemical reactions or be damaged. The non-metallic material selected for the outer protective layer can provide additional protection, wear resistance, UV resistance, and enhance the service life of the pipeline.

[0017] 3. The fiber reinforcement layer of the present invention adopts non-metallic high-strength composite fiber, which can avoid the occurrence of hydrogen embrittlement while ensuring the structural strength of the hose.

[0018] 4. The present invention adds a hydrogen monitoring unit to the outer protective layer, which can realize real-time monitoring of hydrogen leakage, provide timely warning, and prevent potential safety hazards. The optical fiber sensor does not require power support and has the characteristics of passive operation, which is suitable for use in remote or inaccessible environments, thereby enhancing the reliability of the system.

[0019] 5. The present invention can reduce the probability of pipeline damage and accidents through early detection and preventive measures, extend the service life of the pipeline, and reduce maintenance and replacement costs.

[0020] In summary, the present invention can be widely applied in the field of new energy development technology. BRIEF DESCRIPTION OF THE DRAWINGS

[0021] Various other advantages and benefits will become apparent to those skilled in the art upon reading the detailed description of the preferred embodiment below. The accompanying drawings are for illustration purposes only and are not to be considered as limiting the present invention. Throughout the drawings, the same reference numerals are used to denote the same components. In the drawings: Figure 1 This is a schematic diagram of the overall structure of a flexible hydrogen transmission pipeline provided by one embodiment of the present invention; Figure 2 1 is a schematic diagram of the structure of an airtight layer provided by one embodiment of the present invention; Figure 3 is a schematic diagram of an inner fiber reinforcement layer provided by an embodiment of the present invention; Figure 4 is a schematic diagram of an outer fiber reinforcement layer provided by an embodiment of the present invention; Figure 5 is a schematic cross-sectional view of a double-sided fiber reinforced layer provided by one embodiment of the present invention; Figure 6 This is a schematic diagram of an outer protective layer using a LiAlD2 monitoring element provided by one embodiment of the present invention; Figure 7 This is a cross-sectional schematic diagram of a LiAlD2 monitoring element used in an outer protective layer according to an embodiment of the present invention; Figure 8 This is a schematic diagram of a resistance change case of a LiAlD2 monitoring element provided by an embodiment of the present invention; Figure 9 This is a schematic diagram of an optical fiber hydrogen sensor used as an outer protective layer according to an embodiment of the present invention. DETAILED DESCRIPTION

[0022] Exemplary embodiments of the present invention will be described in more detail below with reference to the accompanying drawings. Although exemplary embodiments of the present invention are shown in the accompanying drawings, it should be understood that the present invention can be implemented in various forms and should not be limited by the embodiments set forth herein. Rather, these embodiments are provided to enable a more thorough understanding of the present invention and to fully convey the scope of the present invention to those skilled in the art.

[0023] It should be understood that the terms used herein are for the purpose of describing specific example embodiments only and are not intended to be limiting. Unless the context clearly indicates otherwise, the singular forms "one", "an" and "said" as used herein may also be meant to include plural forms. The terms "comprise", "include", "contain" and "have" are inclusive and therefore specify the presence of stated features, steps, operations, elements and / or parts, but do not exclude the presence or addition of one or more other features, steps, operations, elements, parts, and / or combinations thereof. The method steps, processes, and operations described herein are not to be construed as necessarily requiring them to be performed in the specific order described or illustrated, unless the order of execution is clearly indicated. It should also be understood that additional or alternative steps may be used.

[0024] Although the terms first, second, third, etc. can be used in the text to describe multiple elements, components, regions, layers and / or sections, these elements, components, regions, layers and / or sections should not be limited by these terms. These terms can only be used to distinguish an element, component, region, layer or section from another region, layer or section. Unless the context clearly indicates otherwise, terms such as "first", "second" and other numerical terms do not imply order or sequence when used in the text. Therefore, the first element, component, region, layer or section discussed below can be referred to as the second element, component, region, layer or section without departing from the teaching of the example embodiments.

[0025] For ease of description, spatially relative terms may be used herein to describe the relationship of one element or feature relative to another element or feature as shown in the figures, such as "inside," "outside," "inner side," "outer side," "lower," "upper," etc. Such spatially relative terms are intended to encompass different orientations of the device in use or operation in addition to the orientation depicted in the figures.

[0026] At present, ordinary pipeline steel faces high construction costs and hydrogen embrittlement problems. Thermoplastic reinforced flexible pipes (RTP) are highly regarded as a more optimal mode of transportation. Thermoplastic reinforced flexible pipes are usually composed of an inner lining layer, a reinforcement layer and an outer protective layer. This non-metallic flexible pipe not only has good flexibility, but also has excellent corrosion resistance. At the same time, when thermoplastic reinforced flexible pipes are directly used for hydrogen transportation, the problem of excessive hydrogen permeability may occur. In order to solve the problem of excessive hydrogen permeability of traditional thermoplastic reinforced flexible pipes at this stage, the present invention proposes a hydrogen transmission flexible pipe. The present invention not only significantly reduces hydrogen permeability, but also can monitor hydrogen leakage.

[0027] Example 1 like Figure 1 As shown, this embodiment provides a hydrogen transmission flexible pipeline, including an inner lining layer 1, an airtight layer 2, a fiber reinforced layer 3 and an outer protective layer 4, wherein the inner lining layer 1, the airtight layer 2, the fiber reinforced layer 3 and the outer protective layer 4 are all cylindrical structures, the inner lining layer 1 adopts a non-metallic thermoplastic resin material, the airtight layer 2 is composed of a graphene / alumina hydrogen barrier coating and a metal aluminum layer, the fiber reinforced layer 3 adopts a non-metallic high-strength fiber composite material, the outer protective layer 4 adopts a non-metallic thermoplastic resin material, and the fiber reinforced layer 3 includes a fiber reinforced inner layer 31 and a fiber reinforced outer layer 32.

[0028] The inner lining layer 1, the airtight layer 2, the fiber reinforced inner layer 31, the fiber reinforced outer layer 32 and the outer protective layer 4 are arranged in sequence from the inside to the outside. The airtight layer 2 is wrapped around the outer side of the inner lining layer 1, the fiber reinforced inner layer 31 is wrapped forwardly around the outer side of the airtight layer 2, the fiber reinforced outer layer 32 is wrapped reversely around the outer side of the fiber reinforced inner layer 31, and the outer protective layer 4 is arranged on the outer side of the fiber reinforced outer layer 32.

[0029] A monitoring element is provided inside the outer protective layer 4, which is used to monitor the change in hydrogen concentration or the change in resistance of the outer protective layer 4 in real time, so that the external host computer can judge the hydrogen leakage of the hydrogen transmission flexible pipeline based on the change in hydrogen concentration or the change in resistance of the outer protective layer 4.

[0030] In a preferred embodiment, the non-metallic thermoplastic resin material used for the inner lining layer 1 includes polyvinyl chloride, polyurethane, polyethylene terephthalate or high-density polyethylene.

[0031] In a preferred embodiment, Figure 2 As shown, the airtight layer 2 is provided on the inner lining layer 1 of the cylindrical structure by a winding process. The specific process is as follows: ① Add a first adhesive 21 to the outside of the inner lining layer, and use an extrusion process to add EVOH (ethylene-vinyl copolymer) material 22 between the inner lining layer and the first adhesive aluminum layer.

[0032] ② Add a second binder 23 to the outside of the EVOH material 22. The specific production process is: raw material preparation - extrusion preliminary molding - stretching - shaping - testing. After adding the second binder 23, the EVOH barrier film is prepared.

[0033] ③ An aluminum strip is wound in a forward spiral around the outside of the EVOH barrier film. The wound aluminum strips are combined to form a first adhesive aluminum layer 24. The layup angle of the forward spiral winding is 55°. Alternatively, several aluminum strips are arranged longitudinally around the outside of the EVOH barrier film. The arranged aluminum strips are combined to form the first adhesive aluminum layer 24.

[0034] ④ On the outside of the first bonding aluminum layer 24, an aluminum strip is spirally wound in the reverse direction for a second layer laying. The wound aluminum strips are combined into a second bonding aluminum layer 25, wherein the laying angle of the reverse spiral winding is -55°.

[0035] ⑤ Using a cooling system, the first bonding aluminum layer 4 and the second bonding aluminum layer 25 are processed and fixed into shape.

[0036] ⑥Prepare graphene / alumina hydrogen barrier coating.

[0037] Specifically, the graphene / aluminum oxide hydrogen barrier coating can be prepared by CVD (chemical vapor deposition) combined with transfer method: Graphene is first generated by CVD, and then a single layer or multilayer graphene is transferred to a substrate using a PMMA polymethyl methacrylate method to prepare a graphene / aluminum oxide hydrogen barrier coating.

[0038] Specifically, the graphene / aluminum oxide hydrogen barrier coating can be prepared by spraying: A certain amount of GO (graphene oxide membrane) nanosheet powder was placed in pure water, stirred, and then ultrasonically dispersed at 300W in an ultrasonicator. The water temperature was controlled to prepare a GO solution. This GO solution was then atomized and sprayed using a small spray gun onto the surfaces of polished CLAM (Chinese Low Activation Martensitic Steel) steel discs and cleaned and decontaminated copper substrates (pure copper foil, 1mm thick, ultrasonically cleaned for 10 minutes with a 10wt% aqueous citric acid and acetone solution). This process involved multiple sprayings to form a graphene / alumina hydrogen barrier coating. Finally, a layered graphene / alumina hydrogen barrier coating was prepared using a similar process.

[0039] ⑤ Attach a graphene / aluminum oxide hydrogen barrier coating to the outer surface of the second bonding aluminum layer to further enhance the hydrogen barrier performance.

[0040] ⑥ During the preparation process, the thickness of the graphene / alumina hydrogen barrier coating is controlled by controlling the number of spraying, and the hydrogen permeability of the graphene / alumina hydrogen barrier coating is controlled by for: (1) in, is the atomic collision rate, in atoms·m -2 ·s -1 ; is the energy barrier of the incident atom, in kJ·mol -1 ; is the Boltzmann constant, which is 1.380649×10 -23 J.K. -1 ; is the temperature in K.

[0041] Specifically, the relevant permeation theory of multilayer graphene / alumina hydrogen barrier coating is introduced: From the microscopic mechanism, the graphene / alumina hydrogen barrier coating is formed by the superposition of graphene nanosheets. The theoretical analysis of the permeability of the graphene / alumina hydrogen barrier coating is also based on this nanostructure. According to the relevant experimental and theoretical research on gas permeation membranes, it is known that the gas permeability of the graphene / alumina hydrogen barrier coating is for: (2) in, and are the diffusion coefficient and solubility coefficient of gas through graphene / alumina hydrogen barrier coating respectively; is the effective area of ​​the membrane; is the gas penetration time; is the pressure difference on both sides of the membrane; It is the effective thickness of the film in a vacuum state, and the unit of the physical quantity is consistent with the same physical quantity in the coating permeation theory.

[0042] In a preferred embodiment, the non-metallic high-strength fiber composite material used in the fiber-reinforced inner layer 31 and the fiber-reinforced outer layer 32 includes aramid fiber, glass fiber, carbon fiber, polyester fiber, polypropylene fiber or the like.

[0043] In a preferred embodiment, Figure 3 As shown, the winding angle of the fiber reinforced inner layer 31 is 55°; Figure 4 As shown, the fiber reinforced outer layer 32 has a winding angle of -55°.

[0044] In a preferred embodiment, Figure 5 As shown, the fiber-reinforced inner layer 31 and the fiber-reinforced outer layer 32 are both wound, and on the basis of the inner liner 1 and the airtight layer 2, a double-layer winding tape is made by a semi-dry process using a winding pipe making machine. The specific process is as follows: First, a double-layer wrapping tape made of non-metallic high-strength fiber composite material is pressurized and heated to 120-150°C for 20-40 minutes before being wrapped around the outer side of the airtight layer 2. The use of the double-layer wrapping tape gives the hydrogen transmission flexible pipeline advantages such as high strength, heat resistance, chemical resistance, low expansion, and impact resistance.

[0045] In a preferred embodiment, the non-metallic thermoplastic resin material used for the outer protective layer 4 includes polyvinyl chloride, polyurethane, polyethylene terephthalate or high-density polyethylene.

[0046] In a preferred embodiment, Figure 6 、 Figure 7 、 Figure 9 As shown, the outer protective layer 4 includes an outer protective layer outer wall 41, an outer protective layer inner wall 42 and a monitoring element. The outer protective layer outer wall 41 and the outer protective layer inner wall 42 are both cylindrical structures. A monitoring element is embedded in the cavity 43 between the outer protective layer outer wall 41 and the outer protective layer inner wall 42. In addition to the monitoring element, the cavity is supplemented by the material matrix of the outer protective layer 4, and the overall mechanical properties exist.

[0047] In a preferred embodiment, Figure 6 、 Figure 7 As shown, the monitoring element can be a LiAlD2 monitoring element 44. Hydrogen leaked from the hydrogen transmission flexible pipeline during service will come into contact with the LiAlD2 monitoring element 44 embedded in the outer protective layer 4. Some of the hydrogen is adsorbed by the LiAlD2 monitoring element 44, causing its resistance to change. The more hydrogen adsorbed by the LiAlD2 monitoring element 44, the greater its resistance. The LiAlD2 monitoring element 44 monitors the resistance changes of the outer protective layer 4 in real time. By connecting to an external resistance monitoring system via electrical contacts, the resistance changes of the LiAlD2 monitoring element 44 can be observed remotely, enabling real-time monitoring of hydrogen leaks.

[0048] Specifically, the production process when the monitoring element of the outer protective layer 4 is a LiAlD2 monitoring element 44 is as follows: 1) Embed the LiAlD2 element 44 into the outer protective layer 4: 1.1) Determine the embedding position: Select an area close to the inner wall 42 of the outer protective layer so that it can quickly come into contact with the leaked hydrogen.

[0049] 1.2) Grooving or Pre-reserved Holes: In the design of the outer protective layer 4 , a cavity, such as a groove or a hole, is reserved in advance for placing the LiAlD 2 element 44 .

[0050] 1.3) Fixing the element: The LiAlD2 element 44 is embedded in the reserved cavity and fixed with a material that is chemically resistant and has good thermal conductivity to ensure that the LiAlD2 element 44 can fully contact with the external hydrogen.

[0051] 1.4) Packaging and protection: The LiAlD2 element 44 is packaged with a material having good airtightness to prevent the external environment from affecting the LiAlD2 element 44 while ensuring that hydrogen can enter the contact area.

[0052] 2) Transmission line settings: 2.1) Designing the transmission channel: Considering the wiring channel of the outer protective layer 4, ensuring that the electrical contacts and transmission lines of the LiAlD2 element 44 can be smoothly connected to the outside.

[0053] 2.2) Pre-embedding of wires: In the initial stage of production, the transmission lines are pre-embedded in the outer protective layer 4 to ensure that the cable path is smooth and will not be damaged in subsequent steps.

[0054] 2.3) Sealing: Ensure that the outlet of the transmission line is sealed to prevent hydrogen leakage or external interference.

[0055] 2.4) Connect to the central control room: After production is completed, the transmission line is connected to the external resistance monitoring system to achieve long-distance hydrogen leakage monitoring.

[0056] 3) Precautions during the production process: 3.1) Heat treatment control: When embedding and encapsulating the LiAlD2 element 44, the temperature needs to be strictly controlled to prevent the LiAlD2 element 44 from being damaged by high temperature.

[0057] 3.2) Sealing requirements: Ensure that the LiAlD2 element 44 and the embedding point of the transmission line have good sealing performance to prevent hydrogen leakage from affecting the detection sensitivity of the system.

[0058] 3.3) Electrical performance verification: During the production process, the resistance change of the electrical contacts should be tested multiple times to ensure that it can accurately reflect the hydrogen leakage.

[0059] 3.4) Through reasonable design and strict production control, effective embedding and signal transmission of the LiAlD2 element 44 can be achieved, enabling remote monitoring of hydrogen leaks.

[0060] Specifically, if Figure 8The figure shows a possible example of how the resistance of LiAlD2 monitoring element 44 changes over time. During time period 1, there is no hydrogen leakage near LiAlD2 monitoring element 44, so the resistance of LiAlD2 monitoring element 44 remains constant during time period 1. At the end of time period 1, hydrogen begins to leak at a certain rate during time period 2. The resistance of LiAlD2 monitoring element 44 increases over time, and it absorbs hydrogen at a first adsorption rate. At the end of time period 2, the charging and discharging effects of the hydrogen transmission flexible pipeline cause increased physical damage to the outer protective layer 4 outside the LiAlD2 monitoring element 44 (for example, delamination or microcracks), causing the hydrogen leakage rate to increase during time period 3. Therefore, the rate of change of the resistance of LiAlD2 monitoring element 44 increases faster than during time period 2. At this time, the adsorption rate of LiAlD2 monitoring element 44 is the second adsorption rate. At the end of time period 3, the resistance value corresponding to point X corresponds to the total amount of gaseous hydrogen leaked from the hydrogen transmission flexible pipeline from t = 0 to the end of time period 3.

[0061] In a preferred embodiment, Figure 9 As shown, the monitoring element can be an embedded, spirally wound fiber optic hydrogen sensor 45 based on palladium-modified hexagonal boron nitride. The fiber optic hydrogen sensor 45 is integrated into a cavity 43 between the outer wall 41 and the inner wall 42 of the outer protective layer, and is used to monitor hydrogen leaks in real time. The fiber optic hydrogen sensor 45 has high sensitivity and accuracy, quickly detecting extremely small hydrogen leaks and transmitting them to the host computer via optical signals, providing immediate warning information. Compared to the LiAlD2 monitoring element 44, the fiber optic hydrogen sensor 45 is arranged along the entire length of the pipeline, accurately locating the leak point and facilitating rapid troubleshooting and repair. This precise positioning function can reduce maintenance time and costs, improving the maintenance efficiency of the pipeline system.

[0062] Specifically, the production process of the monitoring element of the outer protective layer 4 using the optical fiber hydrogen sensor 45 based on palladium-modified hexagonal boron nitride is as follows: 1) Design of the fiber optic hydrogen sensor 45 and the outer protective layer 4: Ensure that the design of the fiber optic hydrogen sensor 45 is compatible with the size and structure of the intended hydrogen transmission flexible pipeline. Determine the thickness and structure of the outer protective layer 4 in which the fiber optic hydrogen sensor 45 is embedded, and ensure that the fiber optic hydrogen sensor 45 can be firmly fixed in the hydrogen transmission flexible pipeline.

[0063] 2) Outer Protective Layer 4 Mold Fabrication and Pretreatment: A suitable mold is prepared for embedding the fiber-optic hydrogen sensor 45 during the production of the flexible hydrogen pipeline. The non-metallic material of the outer protective layer 4 is pretreated, such as by heating or adding a plasticizer, to ensure the desired protective layer is formed during production.

[0064] 3) Preparation and Embedment of the Fiber Optic Hydrogen Sensor 45: The fiber optic hydrogen sensor 45, based on palladium-modified hexagonal boron nitride, undergoes the necessary packaging to ensure its stability under high temperature and pressure conditions. The fiber optic hydrogen sensor 45 is then placed in a mold, ensuring its position and orientation within the mold meet the design requirements. An outer protective layer (4) of non-metallic material is injected or extruded into the mold using an injection molding or extrusion process, covering the fiber optic hydrogen sensor 45. This process requires controlled temperature and pressure to avoid damaging the fiber optic hydrogen sensor 45 or affecting its performance.

[0065] 4) Cooling and Curing: After injection molding or extrusion, cool the hydrogen flexible pipe to room temperature to allow the non-metallic material of the outer protective layer 4 to solidify. Inspect the appearance and quality of the finished hydrogen flexible pipe to ensure that the optical fiber hydrogen sensor 45 is properly embedded and not damaged.

[0066] 5) Post-processing: Perform necessary trimming and processing on the hydrogen transmission flexible pipeline, such as cutting or removing excess material. Test the hydrogen transmission flexible pipeline embedded with the optical fiber hydrogen sensor 45 to verify the functionality of the optical fiber hydrogen sensor 45 and the performance of the hose.

[0067] Specifically, during the processing, pay attention to: 1) Material compatibility: The non-metallic outer protective layer 4 may affect the sensor under high temperature conditions, especially during injection molding or extrusion. It is necessary to ensure that the optical fiber hydrogen sensor 45 will not be damaged under these conditions.

[0068] 2) Protection of the optical fiber hydrogen sensor 45: The optical fiber hydrogen sensor 45 is sensitive to environmental changes and mechanical stress and requires careful handling during the production process to avoid damage to the sensor.

[0069] 3) Production process control: Control the temperature and pressure of injection molding or extrusion to avoid adverse effects on the fiber optic hydrogen sensor 45.

[0070] Example 2 This embodiment provides a hydrogen leak detection method, comprising the following steps: 1) Producing the hydrogen transmission flexible pipeline of Example 1.

[0071] 2) Install the hydrogen transmission flexible pipeline at the location where it is required to serve.

[0072] 3) During the service of the hydrogen transmission flexible pipeline, leaked hydrogen comes into contact with the monitoring element embedded in the outer protective layer 4. The monitoring element monitors the change of hydrogen concentration or the resistance change of the outer protective layer 4 in real time and sends it to the host computer.

[0073] Specifically, when the monitoring element is a LiAlD2 monitoring element 44, leaked hydrogen is absorbed by the LiAlD2 monitoring element 44, causing its resistance to change. The more hydrogen absorbed by the LiAlD2 monitoring element 44, the greater its resistance. The LiAlD2 monitoring element 44 is connected to a host computer via electrical contacts, transmitting the resistance change of the outer protective layer 4 to the host computer.

[0074] Specifically, when the monitoring element uses a fiber optic hydrogen sensor 45 based on palladium-modified hexagonal boron nitride, the fiber optic hydrogen sensor 45 monitors the change in hydrogen concentration in real time and transmits the real-time monitoring data to the host computer via an optical signal.

[0075] 4) The host computer determines the hydrogen leakage of the hydrogen transmission flexible pipeline according to the change of hydrogen concentration or the change of resistance of the outer protective layer 4.

[0076] Specifically, when the monitoring element adopts the LiAlD2 monitoring element 44 , the host computer determines the hydrogen leakage of the hydrogen transmission flexible pipeline according to the resistance change of the outer protective layer 4 .

[0077] Specifically, when the monitoring element uses a fiber optic hydrogen sensor 45 based on palladium-modified hexagonal boron nitride, the host computer determines the hydrogen leakage of the hydrogen transmission flexible pipeline according to the change in hydrogen concentration.

[0078] The above embodiments are only used to illustrate the present invention, wherein the structure, connection mode and manufacturing process of each component can be changed. Any equivalent transformations and improvements based on the technical solution of the present invention should not be excluded from the scope of protection of the present invention.

Claims

1. A flexible hydrogen transport pipeline, characterized in that: It includes an inner lining layer, an airtight layer, a fiber-reinforced layer and an outer protective layer, wherein the inner lining layer, the airtight layer, the fiber-reinforced layer and the outer protective layer are all cylindrical structures, the inner lining layer is made of a non-metallic thermoplastic resin material, the airtight layer is composed of a graphene / alumina hydrogen barrier coating and a metal aluminum layer, the fiber-reinforced layer is made of a non-metallic high-strength fiber composite material, the outer protective layer is made of a non-metallic thermoplastic resin material, and the fiber-reinforced layer includes a fiber-reinforced inner layer and a fiber-reinforced outer layer; The airtight layer is wound around the outer side of the inner lining layer, the fiber-reinforced inner layer is forwardly wound around the outer side of the airtight layer, the fiber-reinforced outer layer is reversely wound around the outer side of the fiber-reinforced inner layer, and the outer protective layer is arranged on the outer side of the fiber-reinforced outer layer; A monitoring element is provided in the outer protective layer, and the monitoring element is used to monitor the change of hydrogen concentration or the change of resistance of the outer protective layer in real time, so that an external host computer can judge the hydrogen leakage of the hydrogen transmission flexible pipeline according to the change of hydrogen concentration or the change of resistance of the outer protective layer.

2. A hydrogen transport flexible pipeline as claimed in claim 1, characterized in that: The airtight layer is arranged on the inner lining layer of the cylindrical structure by a winding process, and the specific process is as follows: A first adhesive is added to the outer side of the inner liner, and an EVOH material is added between the inner liner and the first bonding aluminum layer by using an extrusion process; Adding a second binder to the outside of the EVOH material, and preparing the EVOH barrier film after adding the second binder; An aluminum strip is used to spirally wind one circle in the positive direction on the outside of the EVOH barrier film, and the wound aluminum strips are combined into a first bonding aluminum layer; or, a plurality of aluminum strips are longitudinally arranged one circle on the outside of the EVOH barrier film, and the arranged aluminum strips are combined into a first bonding aluminum layer; On the outer side of the first bonding aluminum layer, an aluminum strip is spirally wound in the reverse direction for a round to perform secondary lamination, and the wound aluminum strips are combined into a second bonding aluminum layer; Using a cooling system to process and fix the first bonding aluminum layer and the second bonding aluminum layer into shape; Attaching a graphene / aluminum oxide hydrogen barrier coating on the outer surface of the second bonding aluminum layer; During the preparation process, the thickness of the graphene / aluminum oxide hydrogen barrier coating is controlled by controlling the number of spraying times.

3. A hydrogen transport flexible pipeline as claimed in claim 2, characterized in that: The graphene / aluminum oxide hydrogen barrier coating is prepared by a CVD combined transfer method or a spraying method.

4. A hydrogen transport flexible pipeline as claimed in claim 1, characterized in that: The ply angle of the aluminum strips in the first bonding aluminum layer that are spirally wound in the forward direction is 55°, and the ply angle of the aluminum strips in the second bonding aluminum layer that are spirally wound in the reverse direction is -55°.

5. The hydrogen transport flexible pipeline according to claim 1, characterized in that: The winding angle of the fiber-reinforced inner layer is 55°, and the winding angle of the fiber-reinforced outer layer is -55°.

6. The hydrogen transport flexible pipeline according to claim 1, characterized in that: The outer protective layer comprises an outer protective layer outer wall, an outer protective layer inner wall and the monitoring element; The outer wall of the outer protective layer and the inner wall of the outer protective layer are both cylindrical structures, and the monitoring element is embedded in the cavity between the outer wall of the outer protective layer and the inner wall of the outer protective layer.

7. A hydrogen transport flexible pipeline as claimed in claim 6, characterized in that: The monitoring element adopts a LiAlD2 monitoring element, which is used to monitor the resistance change of the outer protective layer in real time and is connected to a host computer through an electrical contact.

8. A hydrogen transport flexible pipeline as claimed in claim 6, characterized in that: The optical fiber hydrogen sensor based on palladium-modified hexagonal boron nitride embedded in a spiral winding is integrated in a cavity between the outer wall of the outer protective layer and the inner wall of the outer protective layer, and is used to monitor hydrogen leakage in real time and transmit it to a host computer via an optical signal.

9. A method for detecting hydrogen leakage, characterized in that: include: Producing a flexible hydrogen transport pipeline as claimed in any one of claims 1 to 8; Setting the hydrogen transmission flexible pipeline at the location where it is required to serve; During the service of the hydrogen transmission flexible pipeline, the leaked hydrogen comes into contact with the monitoring element embedded in the outer protective layer. The monitoring element monitors the change of hydrogen concentration or the change of resistance of the outer protective layer in real time and sends it to the host computer; The host computer determines the hydrogen leakage of the hydrogen transmission flexible pipeline according to the change of hydrogen concentration or the change of resistance of the outer protective layer.

10. A hydrogen leak detection method according to claim 9, characterized in that: During the service of the hydrogen transmission flexible pipeline, the leaked hydrogen contacts the monitoring element embedded in the outer protective layer, and the monitoring element monitors the change of hydrogen concentration or the change of resistance of the outer protective layer in real time and sends it to the host computer, including: When the monitoring element adopts LiAlD2 monitoring element, the leaked hydrogen is adsorbed by the LiAlD2 monitoring element, causing its resistance to change. The more hydrogen the LiAlD2 monitoring element adsorbs, the greater its resistance. The LiAlD2 monitoring element is connected to the host computer through the electrical contact, and the resistance change of the outer protective layer is sent to the host computer. When the monitoring element adopts a fiber optic hydrogen sensor based on palladium-modified hexagonal boron nitride, the fiber optic hydrogen sensor monitors the changes in hydrogen concentration in real time and transmits the real-time monitoring data to the host computer through optical signals.

Images