Non-metal hydrogen delivery pipeline and preparation method thereof

Abstract

The application discloses a non-metal hydrogen conveying pipeline and a preparation method thereof, and belongs to the technical field of hydrogen conveying pipelines. The hydrogen conveying pipeline comprises two first connectors, two second connectors and a non-metal pipeline. The first connector is internally hollow to form a gas conveying cavity. The first end of the first connector is externally convex to form a connecting portion. A connecting hole is arranged on the connecting portion and is used for being connected with an external connector. The second end of the first connector is externally convex to form a limiting portion. The second connector is fixedly connected to the inside of the first connector. The non-metal pipeline comprises, from inside to outside, a base pipe, an inner winding layer, a foam layer and an outer winding layer. The two ends of the base pipe are fixedly connected with the two second connectors respectively. The two ends of the foam layer are connected with the limiting portions of the two first connectors respectively. The hydrogen conveying pipeline has higher hydrogen barrier performance, can improve the weather resistance and anti-aging effect of the hydrogen conveying pipeline, and ensures the safety in the hydrogen conveying process.

Description

Technical Field

[0001] This application relates to a non-metallic hydrogen transmission pipeline and its preparation method, belonging to the field of hydrogen transmission pipeline technology. Background Technology

[0002] During transportation, hydrogen is easily contaminated by impurities and moisture in the environment, making it difficult to maintain high purity. Metal pipelines, on the other hand, are susceptible to oxidation and corrosion over long-term use, leading to surface corrosion and rust. This can severely impact the delivery, quality, and safety of hydrogen. In contrast, non-metallic pipelines can be made from suitable materials based on the properties of the transported medium, giving them better corrosion resistance and effectively preventing hydrogen contamination and pipeline corrosion.

[0003] Compared to traditional metal pipes, non-metallic pipes have advantages such as being lightweight, flexible, and easy to maintain. This makes non-metallic pipes more suitable for the requirements of hydrogen transportation, enabling more efficient, safe, and reliable gas delivery.

[0004] However, most current non-metallic hydrogen transport pipelines employ an anti-corrosion coating on the surface of plastic pipes to improve their barrier properties, prevent hydrogen leakage, and enhance safety. Existing technologies also improve structural stability and hydrogen barrier performance under high-pressure hydrogen conditions by optimizing braiding angles and tension distribution. For example, Chinese patent CN120466497B discloses a flexible hydrogen transport pipe, its preparation method, and a hydrogen leakage detection system. The inner pressure-bearing layer of this flexible pipe is reinforced with high-strength fibers, which, after braiding, can withstand high internal hydrogen pressure. While this patent enhances the ability to withstand internal hydrogen pressure, during long-term hydrogen transport, a single inner pressure layer is insufficient to withstand hydrogen pressure and cannot simultaneously provide gas barrier and safety protection. Especially during installation and transportation, the hydrogen transport pipe prepared by this patent cannot effectively buffer external impacts, thus affecting its normal use.

[0005] Therefore, there is an urgent need for a non-metallic hydrogen pipeline that can prevent hydrogen leakage and has a good buffering effect. Summary of the Invention

[0006] To address the aforementioned issues, a non-metallic hydrogen transport pipeline is provided. This pipeline enhances the pressure resistance of the non-metallic hydrogen transport pipeline and prevents it from rupturing through the coordinated action of the inner and outer winding layers. Simultaneously, a foam layer is placed between the inner and outer winding layers, which not only effectively prevents hydrogen leakage but also provides a certain buffering effect.

[0007] This application provides a non-metallic hydrogen transport pipeline, comprising: Two first connectors, each first connector having a hollow interior forming an air delivery chamber, a first end of the first connector protruding outward to form a connecting part, the connecting part being provided with a connecting hole for connecting to an external connector, and a second end of the first connector protruding outward to form a limiting part; Two second connectors are fixedly connected inside the first connector; The non-metallic tube comprises, from the inside out, a base tube, an inner winding layer, a foam layer, and an outer winding layer. The two ends of the base tube are respectively fixedly connected to two second connectors; the two ends of the foam layer are respectively connected to the limiting portions of the two first connectors.

[0008] Optionally, the first connector connection portion is provided with a snap-fit ​​groove near the air delivery chamber, and the first end of the second connector protrudes outward to form a snap-fit ​​portion, which snaps into the snap-fit ​​groove.

[0009] Another aspect of this application provides a method for preparing a non-metallic hydrogen transport pipeline, comprising the following steps: A1: After the two ends of the base tube are fixedly connected to the two second connectors respectively, the modified carbon fiber bundles impregnated with the impregnation liquid are wound around the outer wall of the base tube and part of the outer wall of the second connector. After heating and curing, an inner winding layer is formed. A2: Place the two second connectors on the outside of the two first connectors respectively, cover the surface of the inner winding layer with a foam layer, and place the foam layer between the limiting parts of the two first connectors. A3: Modified carbon fiber bundles impregnated with impregnation liquid are wound onto the surface of the foam layer and part of the surface of the first joint. After heating and curing, an outer winding layer is formed, resulting in a non-metallic hydrogen transmission pipeline.

[0010] Optionally, the base tube, by mass fraction, comprises: 80-100 parts of polyethylene, 20-30 parts of high-density polyethylene, 20-30 parts of polyethylene-vinyl acetate, 10-20 parts of modified composite filler, and 10-20 parts of compatibilizer. The modified composite filler is obtained by mixing the composite filler with a modifier and then drying it.

[0011] This application incorporates polyethylene vinyl acetate, introducing vinyl acetate groups to improve the impact resistance of the hydrogen transport pipeline. Simultaneously, the added vinyl acetate groups absorb some ultraviolet radiation, slowing down photoaging and enhancing the weather resistance of the pipeline. Furthermore, by limiting the amount of each component, the toughness of the base pipe is ensured, while also improving its pressure resistance and oxidation resistance.

[0012] Optionally, the composite filler is selected from at least two of nano-graphene oxide, nano-silica, and nano-titanium dioxide.

[0013] In this application, by adding nanoscale graphene oxide, silicon dioxide, and titanium dioxide, two things are achieved: first, the tiny pores between polyethylene molecular chains can be filled, reducing hydrogen molecule diffusion channels; second, the nanoparticles can restrict the peristalsis of polyethylene molecular chains, reducing creep under long-term pressure.

[0014] Optionally, the modifier is a silane coupling agent KH550.

[0015] Modifying the composite filler with a modifier can effectively improve the compatibility between the composite filler and the base tube matrix, significantly enhance the barrier performance against hydrogen molecules, reduce hydrogen permeation loss, and improve the efficiency and safety of hydrogen transportation.

[0016] Optionally, the content of vinyl acetate segments in the polyethylene-vinyl acetate is 30-40%.

[0017] Preferably, the content of vinyl acetate segments in the polyethylene-vinyl acetate is 32-36%.

[0018] By limiting the content of vinyl acetate segments in polyethylene-vinyl acetate, the prepared base pipe has better elasticity and weather resistance, improves its ability to withstand hydrogen pressure, avoids the problem of base pipe rupture, and extends the service life of hydrogen transportation pipelines.

[0019] If the content of vinyl acetate segments is too high, the content of polar groups will increase, which will increase the gap between polyethylene-vinyl acetate molecular chains, making it impossible to form a dense crystalline barrier layer. This will reduce the density of the base tube and make it prone to hydrogen leakage. If the content of vinyl acetate segments is too low, the pressure resistance of the base tube cannot be effectively improved.

[0020] Optionally, the compatibilizer includes at least one of polyethylene grafted maleic anhydride and ethylene-vinyl acetate copolymer.

[0021] Adding a compatibilizer can effectively improve the compatibility between polyethylene and polyethylene-vinyl acetate, enhance the tightness and gas barrier properties of the base pipe, and further prevent hydrogen leakage.

[0022] Optionally, the impregnation solution comprises polyvinylidene fluoride.

[0023] The polyvinylidene fluoride in this application has extremely low hydrogen permeability, good chemical stability and corrosion resistance, and can effectively prevent hydrogen permeation and corrosion from external chemicals.

[0024] Optionally, the impregnation liquid may further include a curing agent, an organic solvent, and an epoxy resin.

[0025] Optionally, the modified carbon fiber bundles are prepared as follows: B1: After carbon fiber undergoes oxidation treatment, it is filtered, washed, and dried to obtain pretreated carbon fiber; B2: Mix pretreated carbon fiber with 10-20 times the amount of anhydrous ethanol, add silane coupling agent containing double bonds, the mass ratio of pretreated carbon fiber to silane coupling agent containing double bonds is 1:(1.2-2), mix evenly, heat to 60-70℃, then filter, wash and dry to obtain carbon fiber containing double bonds. B3: Carbon fibers containing double bonds, 2-mercapto-4-methylimidazole and anhydrous ethanol are mixed, an inert gas is introduced as a protective gas, a photoinitiator is added, and the reaction is carried out under ultraviolet light with stirring. After the reaction is completed, the solvent is removed, and the mixture is washed and dried to obtain modified carbon fibers. B4: Modified carbon fiber bundles are obtained by spinning and twisting modified carbon fibers.

[0026] Carbon fibers are oxidized to generate a large number of oxygen-containing groups on their surface. Then, a silane coupling agent containing double bonds is added to react and obtain carbon fibers containing double bonds. When carbon fibers containing double bonds, 2-mercapto-4-methylimidazole, and anhydrous ethanol are mixed under ultraviolet light, the thiol groups in 2-mercapto-4-methylimidazole react with the double bonds in the carbon fibers containing double bonds to obtain modified carbon fibers with thioether groups and imidazole groups on the surface. This gives them excellent resistance to ultraviolet light, aging, and chemical corrosion. After spinning and twisting, modified carbon fiber bundles are obtained. When the carbon fiber bundles are wound onto the base pipe or foam layer through an impregnation solution, the hydrogen transportation pipeline can adapt to complex and changing environments and extend the service life of the hydrogen transportation pipeline.

[0027] Furthermore, the combined use of the inner and outer winding layers effectively improves the various performance characteristics of the hydrogen transmission pipeline. The inner winding layer effectively blocks hydrogen gas from the inside, while also effectively stabilizing the pressure resistance of the base pipe and improving the corrosion resistance of the hydrogen transmission pipeline. The outer winding layer effectively blocks ultraviolet rays on the surface of the hydrogen transmission pipeline, improving its aging resistance and chemical corrosion resistance, thereby extending the service life of the hydrogen transmission pipeline.

[0028] Optionally, the silane coupling agent containing double bonds is at least one of vinyltrimethoxysilane, vinyltriethoxysilane, vinylmethyldimethoxysilane, and vinylmethyldiethoxysilane.

[0029] Optionally, the mass ratio of the carbon fiber containing double bonds, 2-mercapto-4-methylimidazole, and anhydrous ethanol is 1:(0.2-0.6):(30-40).

[0030] At this ratio, the double bonds and thiol groups can fully react, effectively introducing thioether and imidazole groups, improving the anti-aging ability of the modified carbon fiber bundles, and thus extending the service life of the hydrogen transmission pipeline.

[0031] Optionally, the ultraviolet light treatment is divided into two stages. The first stage uses ultraviolet light with a dominant wavelength of 254 nm and an irradiance of 10-15 mw / cm². 2 The reaction is carried out for 10-20 minutes; the second stage is conducted under ultraviolet light with a dominant wavelength of 365 nm and an intensity of 15-25 mw / cm². 2 Allow the reaction to proceed for 30-50 minutes.

[0032] In the first stage of the reaction, low light intensity and a relatively low dominant ultraviolet wavelength are used to slow down the reaction rate, ensuring that the double bond and thiol group react fully and avoiding a violent reaction that could affect the final product. Subsequently, the light intensity and dominant ultraviolet wavelength are increased to accelerate the reaction between the double bond and thiol group and shorten the reaction time. By controlling the wavelength and light intensity in both the first and second stages of the reaction, stable reaction is ensured, achieving a complete reaction between the double bond and thiol group.

[0033] The beneficial effects of this application include, but are not limited to: 1. The non-metallic pipeline according to this application forms a double barrier against hydrogen through the synergistic cooperation of the inner and outer winding layers, which has a higher hydrogen barrier performance. At the same time, the carbon fiber bundles of the inner and outer winding layers are modified to improve the weather resistance and anti-aging effect of the hydrogen pipeline, ensuring the safety of hydrogen transportation.

[0034] 2. According to the non-metallic pipeline of this application, after the first connector is connected to the base pipe, an inner winding layer is used to further fix the two, which effectively improves the connection stability of the two. After the second connector is connected to the first connector, an outer winding layer is used to fix the first connector, the foam layer and the inner winding layer, which improves the connection stability of the first connector, the second connector and the base pipe, and facilitates the subsequent installation and disassembly of the hydrogen transmission pipeline.

[0035] 3. According to the non-metallic pipeline of this application, by adding polyvinylidene fluoride to the impregnation solution, the bonding stability between the modified carbon fiber bundles and the base pipe and the foam layer is enhanced. Polyvinylidene fluoride has extremely low hydrogen permeability, good chemical stability and corrosion resistance, which can effectively prevent hydrogen permeation and corrosion by external chemicals, thereby extending the service life of the hydrogen transmission pipeline. Attached Figure Description

[0036] The accompanying drawings, which are included to provide a further understanding of this application and form part of this application, illustrate exemplary embodiments and are used to explain this application, but do not constitute an undue limitation of this application. In the drawings: Figure 1 This is a schematic diagram of the hydrogen transport pipeline involved in Embodiment 1 of this application.

[0037] List of components and reference numerals: 10. First connector; 11. Connecting part; 111. Connecting hole; 12. Limiting part; 20. Second connector; 21. Snap-fit ​​part; 31. Base tube; 32. Inner winding layer; 33. Foam layer; 34. Outer winding layer. Detailed Implementation

[0038] The present application is described in detail below with reference to the embodiments, but the present application is not limited to these embodiments.

[0039] Unless otherwise specified, the raw materials used in the embodiments and comparative examples of this application were all purchased commercially.

[0040] In this application, polyethylene-vinyl acetate with a molecular weight of 1000-2000 can be prepared in-house using methods disclosed in the prior art, or it can be purchased from the market; vinyltrimethoxysilane CAS number: 2768-02-7; vinylmethyldiethoxysilane CAS number: 5507-44-8; ethylene-grafted maleic anhydride CAS number: 9006-26-2; 2-mercapto-4-methylimidazolium CAS number: 3247-70-9; benzophenone CAS number: 119-61-9; polyvinylidene fluoride CAS number: 24937-79-9; N,N-dimethylformamide CAS number: 68-12-2; the epoxy resin used in the embodiments of this application is bisphenol A type epoxy resin CAS number: 25085-99-8.

[0041] The oxidation treatment methods described in this application include various forms of treatment such as hydrogen peroxide, nitric acid, and plasma, which can be selected by those skilled in the art as needed.

[0042] In this application, the base tube is prepared by an extrusion molding method commonly used in the art. The first connector is a metal connector, and the specific material can be selected by those skilled in the art as needed. The second connector is prepared by an injection molding method commonly used in the art, and the material is selected from at least one of PE, PA and HDPE.

[0043] The curing agent used in this application may be any one or more of alkaline curing agents and acidic curing agents, and the specific type of curing agent mentioned above does not constitute a limitation on this application.

[0044] Example 1 refer to Figure 1This embodiment relates to a non-metallic hydrogen transport pipeline, comprising: two first connectors 10, each first connector 10 having a hollow interior forming a gas transport cavity; a first end of each first connector 10 protruding outward to form a connecting portion 11, the connecting portion 11 having a connecting hole 111 for connecting to an external connector; and a second end of each first connector 10 protruding outward to form a limiting portion 12; two second connectors 20, each second connector 20 being fixedly connected inside the first connectors 10; and a non-metallic tube, which, from the inside out, comprises a base tube 31, an inner winding layer 32, a foam layer 33, and an outer winding layer 34, with both ends of the base tube 31 being fixedly connected to the two second connectors 20; and the foam layer 33 being a foam layer 33, with both ends of the foam layer 33 being connected to the limiting portions 12 of the two first connectors 10.

[0045] First, the two ends of the base tube 31 are fixedly connected to the two second connectors 20. Then, modified fiber bundles are wound onto the outer wall of the base tube 31 and part of the outer wall of the two second connectors 20 to form an inner winding layer 32. Next, the two first connectors 10 are respectively fitted onto the outside of the two second connectors 20 and fixedly connected. Then, a foam layer 33 is covered on the surface of the inner winding layer 32, and the foam layer 33 is disposed between the limiting parts 12 of the two first connectors 10. The thickness of the foam layer 33 is the same as the height of the limiting parts 12 of the two first connectors 10. Finally, modified fiber bundles are wound onto the surface of the foam layer 33 and part of the outer wall of the first connectors 10 to form an outer winding layer 34.

[0046] This application, through the synergistic arrangement of an inner winding layer 32 and an outer winding layer 34, not only enhances the pressure-bearing capacity of the non-metallic hydrogen transmission pipeline but also extends its service life. Furthermore, the addition of a foam layer 33 effectively buffers external impacts during transportation and installation, reducing damage and disruption to the pipeline. In addition, the non-metallic hydrogen transmission pipeline is equipped with a first connector 10 and a second connector 20, facilitating installation and disassembly.

[0047] Specifically, the connection method between the second connector 20 and the base tube 31 is not specifically limited. It can be welding or bonding, with welding being preferred. When selecting the welding method, it can be infrared welding, laser welding, hot plate welding, etc., as long as it can achieve a fixed connection between the second connector 20 and the base tube 31.

[0048] Specifically, the connection method between the first connector 10 and the second connector 20 can be adhesive bonding or assembly connection, as long as the first connector 10 and the second connector 20 can be fixedly connected. Furthermore, the connection method between the limiting part 12 of the first connector 10 and the inner winding layer 32 on the outer surface of the base tube 31 is not specifically limited, as long as the two can be fixedly connected.

[0049] In a preferred embodiment, the first connector 10 has a snap-fit ​​groove at the position of the connecting part 11 near the air supply chamber, and the first end of the second connector 20 protrudes outward to form a snap-fit ​​part 21, which snaps into the snap-fit ​​groove.

[0050] This setup effectively improves the connection stability between the first connector 10 and the second connector 20, facilitating installation and subsequent maintenance and repair, and extending the service life of the hydrogen pipeline.

[0051] Example 2 This embodiment relates to a method for preparing a non-metallic hydrogen transport pipeline, including the following steps: A1: After the two ends of the base tube 31 are fixedly connected to the two second connectors 20 respectively, the modified carbon fiber bundle impregnated with the impregnation liquid is wound around the outer wall of the base tube 31 and part of the outer wall of the second connector 20. It is heated to 130°C and cured for 3 hours, then heated to 150°C and cured for 4 hours, and finally cured at 80°C for 5 hours to form the inner winding layer 32. A2: The two first connectors 10 are respectively fitted onto the outside of the two second connectors 20, and the surface of the inner winding layer 32 is covered with a foam layer 33, and the foam layer 33 is disposed between the limiting part 12 of the two first connectors 10. A3: Modified carbon fiber bundles impregnated with impregnation liquid are wound onto the surface of foam layer 33 and part of the surface of first joint 10, heated to 130°C and cured for 3 hours, then heated to 150°C and cured for 4 hours, and finally cured at 80°C for 5 hours to form outer winding layer 34, thus obtaining non-metallic hydrogen transmission pipeline.

[0052] The base tube 31, by mass fraction, comprises: 80 parts of polyethylene, 20 parts of high-density polyethylene, 20 parts of polyethylene-vinyl acetate (vinyl acetate chain segment content is 30%), 10 parts of modified composite filler, and 10 parts of ethylene-vinyl acetate copolymer. The polyethylene, high-density polyethylene, polyethylene-vinyl acetate, modified composite filler, and polyethylene grafted maleic anhydride are mixed evenly, heated to a molten state, and extruded to obtain the base tube 31.

[0053] Preparation of modified composite filler: Silane coupling agent KH550 was mixed with anhydrous ethanol solution, and a composite filler of nano-graphene oxide and nano-silica with a mass ratio of 1:1 was added. The mass ratio of silane coupling agent KH550, anhydrous ethanol and composite filler was 1:10:5. The mixture was ultrasonically treated at 60℃ for 2 hours, and then centrifuged and dried to obtain the modified composite filler.

[0054] The preparation method of modified carbon fiber bundles is as follows: B1: After carbon fiber undergoes oxidation treatment, it is filtered, washed, and dried to obtain pretreated carbon fiber; B2: Mix pretreated carbon fibers with 10 times the amount of anhydrous ethanol, add vinyltrimethoxysilane, the mass ratio of pretreated carbon fibers to vinyltrimethoxysilane is 1:1.2, mix evenly, heat to 60°C, then filter, wash and dry to obtain carbon fibers containing double bonds. B3: Carbon fibers containing double bonds, 2-mercapto-4-methylimidazole, and anhydrous ethanol are mixed in a mass ratio of 1:0.2:30. Nitrogen gas is introduced as a protective gas, and benzophenone is added. The first stage is carried out under ultraviolet light with a dominant wavelength of 254 nm and an irradiance of 15 mW / cm². 2 The reaction was carried out for 20 minutes; the second stage was conducted under ultraviolet light with a dominant wavelength of 365 nm and an irradiance of 25 mW / cm². 2 The reaction was carried out for 30 minutes. After the reaction was completed, the solvent was removed by rotary evaporation, and the product was washed and dried to obtain modified carbon fibers. B4: Modified carbon fiber bundles are obtained by spinning and twisting modified carbon fibers.

[0055] The impregnation solution comprises polyvinylidene fluoride, N,N-dimethylformamide, epoxy resin, and curing agent in a mass ratio of 1:4:10:0.2.

[0056] Example 3 This embodiment relates to a method for preparing a non-metallic hydrogen transport pipeline, including the following steps: A1: After the two ends of the base tube 31 are fixedly connected to the two second connectors 20 respectively, the modified carbon fiber bundle impregnated with the impregnation liquid is wound around the outer wall of the base tube 31 and part of the outer wall of the second connector 20. It is heated to 130°C and cured for 3 hours, then heated to 150°C and cured for 4 hours, and finally cured at 80°C for 5 hours to form the inner winding layer 32. A2: The two first connectors 10 are respectively fitted onto the outside of the two second connectors 20, and the surface of the inner winding layer 32 is covered with a foam layer 33, and the foam layer 33 is disposed between the limiting parts 12 of the two first connectors 10. A3: Modified carbon fiber bundles impregnated with impregnation liquid are wound onto the surface of foam layer 33 and part of the surface of first joint 10, heated to 130°C and cured for 3 hours, then heated to 150°C and cured for 4 hours, and finally cured at 80°C for 5 hours to form outer winding layer 34, thus obtaining non-metallic hydrogen transmission pipeline.

[0057] The base tube 31, by mass fraction, comprises: 100 parts of polyethylene, 30 parts of high-density polyethylene, 30 parts of polyethylene-vinyl acetate (vinyl acetate chain segment content is 40%), 20 parts of modified composite filler, and 20 parts of ethylene-vinyl acetate copolymer. The polyethylene, high-density polyethylene, polyethylene-vinyl acetate, modified composite filler, and polyethylene grafted maleic anhydride are mixed evenly, heated to a molten state, and extruded to obtain the base tube 31.

[0058] Preparation of modified composite filler: Silane coupling agent KH550 was mixed with anhydrous ethanol, and a composite filler of nano-silica and nano-titanium dioxide with a mass ratio of 2:1.5 was added. The mass ratio of silane coupling agent KH550, anhydrous ethanol and composite filler was 1:10:5. The mixture was ultrasonically treated at 60℃ for 2 hours, and then centrifuged and dried to obtain the modified composite filler.

[0059] The preparation method of modified carbon fiber bundles is as follows: B1: After carbon fiber undergoes oxidation treatment, it is filtered, washed, and dried to obtain pretreated carbon fiber; B2: Mix pretreated carbon fiber with 20 times the amount of anhydrous ethanol, add vinyltriethoxysilane, the mass ratio of pretreated carbon fiber to vinyltriethoxysilane is 1:2, mix evenly, heat to 60°C, then filter, rinse and dry to obtain carbon fiber containing double bonds. B3: Carbon fibers containing double bonds, 2-mercapto-4-methylimidazole, and anhydrous ethanol are mixed in a mass ratio of 1:0.6:40. Nitrogen gas is introduced as a protective gas, and benzophenone is added. The first stage is carried out under ultraviolet light with a dominant wavelength of 254 nm and an irradiation intensity of 10 mW / cm². 2 The reaction was carried out for 20 minutes; the second stage was conducted under ultraviolet light with a dominant wavelength of 365 nm and an irradiance of 15 mW / cm². 2 The reaction was carried out for 30 minutes. After the reaction was completed, the solvent was removed by rotary evaporation, and the product was washed and dried to obtain modified carbon fibers. B4: Modified carbon fiber bundles are obtained by spinning and twisting modified carbon fibers.

[0060] The impregnation solution comprises polyvinylidene fluoride, N,N-dimethylformamide, epoxy resin, and curing agent in a mass ratio of 1:4:10:0.2.

[0061] Example 4 This embodiment relates to a method for preparing a non-metallic hydrogen transport pipeline, including the following steps: A1: After the two ends of the base tube 31 are fixedly connected to the two second connectors 20 respectively, the modified carbon fiber bundle impregnated with the impregnation liquid is wound around the outer wall of the base tube 31 and part of the outer wall of the second connector 20. It is heated to 130°C and cured for 3 hours, then heated to 150°C and cured for 4 hours, and finally cured at 80°C for 5 hours to form the inner winding layer 32. A2: The two first connectors 10 are respectively fitted onto the outside of the two second connectors 20, and the surface of the inner winding layer 32 is covered with a foam layer 33, and the foam layer 33 is disposed between the limiting parts 12 of the two first connectors 10. A3: Modified carbon fiber bundles impregnated with impregnation liquid are wound onto the surface of foam layer 33 and part of the surface of first joint 10, heated to 130°C and cured for 3 hours, then heated to 150°C and cured for 4 hours, and finally cured at 80°C for 5 hours to form outer winding layer 34, thus obtaining non-metallic hydrogen transmission pipeline.

[0062] The base pipe 31, by mass fraction, comprises: 90 parts of polyethylene, 25 parts of high-density polyethylene, 25 parts of polyethylene-vinyl acetate (vinyl acetate chain segment content is 35%), 15 parts of modified composite filler, and 15 parts of polyethylene grafted maleic anhydride. After the polyethylene, high-density polyethylene, polyethylene-vinyl acetate, modified composite filler, and polyethylene grafted maleic anhydride are mixed evenly, heated to a molten state, and then extruded to obtain the base pipe 31.

[0063] Preparation of modified composite filler: Silane coupling agent KH550 was mixed with anhydrous ethanol, and a composite filler of nano-graphene oxide and nano-titanium dioxide with a mass ratio of 1:1 was added. The mass ratio of silane coupling agent KH550, anhydrous ethanol and composite filler was 1:10:5. The mixture was ultrasonically treated at 60℃ for 2 hours, and then centrifuged and dried to obtain the modified composite filler.

[0064] The preparation method of modified carbon fiber bundles is as follows: B1: After carbon fiber undergoes oxidation treatment, it is filtered, washed, and dried to obtain pretreated carbon fiber; B2: Mix pretreated carbon fibers with 15 times the amount of anhydrous ethanol, add vinylmethyldiethoxysilane, the mass ratio of pretreated carbon fibers to vinylmethyldiethoxysilane is 1:1.6, mix evenly, heat to 60°C, then filter, rinse and dry to obtain carbon fibers containing double bonds. B3: Carbon fibers containing double bonds, 2-mercapto-4-methylimidazole, and anhydrous ethanol are mixed in a mass ratio of 1:0.4:35. Nitrogen gas is introduced as a protective gas, and benzophenone is added. The first stage is carried out under ultraviolet light with a dominant wavelength of 254 nm and an irradiance of 12 mw / cm². 2The reaction was carried out for 25 minutes; the second stage was conducted under ultraviolet light with a dominant wavelength of 365 nm and an irradiance of 20 mW / cm². 2 The reaction was carried out for 40 minutes. After the reaction was completed, the solvent was removed by rotary evaporation, and the product was washed and dried to obtain modified carbon fibers. B4: Modified carbon fiber bundles are obtained by spinning and twisting modified carbon fibers.

[0065] The impregnation solution comprises polyvinylidene fluoride, N,N-dimethylformamide, epoxy resin, and curing agent in a mass ratio of 1:4:10:0.2.

[0066] Example 5 The difference between this embodiment and embodiment 4 is that the composite filler is not modified; otherwise, they are the same as in embodiment 4.

[0067] Example 6 The difference between this embodiment and Embodiment 4 is that the content of vinyl acetate segments in polyethylene-vinyl acetate is 10%, while the rest is the same as in Embodiment 4.

[0068] Example 7 The difference between this embodiment and Embodiment 4 is that the modified carbon fiber bundles are replaced with carbon fiber bundles, while the rest is the same as Embodiment 4.

[0069] Example 8 The difference between this embodiment and embodiment 4 is that the mass ratio of double-bonded carbon fiber, 2-mercapto-4-methylimidazole and anhydrous ethanol is 1:0.05:30, and the rest is the same as in embodiment 4.

[0070] Example 9 The difference between this embodiment and Embodiment 4 is that the ultraviolet light treatment uses a dominant wavelength of 254nm and an irradiance of 10mw / cm². 2 The reaction was carried out for 20 minutes, and the rest was the same as in Example 4.

[0071] Comparative Example 1 The difference between this comparative example and Example 4 is that the hydrogen transport pipeline does not have an inner winding layer 32. The preparation method of this hydrogen transport pipeline includes the following steps: A1: The two ends of the base tube 31 are respectively fixedly connected to two second connectors 20; A2: The two first connectors 10 are respectively fitted onto the outside of the two second connectors 20, and the outer wall of the base tube 31 and part of the outer wall of the second connector 20 are covered with a foam layer 33, and the foam layer 33 is disposed between the limiting part 12 of the two first connectors 10. A3: Modified carbon fiber bundles impregnated with impregnation liquid are wound onto the surface of foam layer 33 and part of the surface of first connector 10, heated to 130°C and cured for 3 hours, then heated to 150°C and cured for 4 hours, and finally cured at 80°C for 5 hours to form outer winding layer 34, thus obtaining non-metallic hydrogen transport pipeline; the rest is the same as in Example 4.

[0072] Comparative Example 2 The difference between this comparative example and Example 4 is that there is no foam layer 33 in the hydrogen delivery pipeline. The preparation method of this hydrogen delivery pipeline includes the following steps: A1: After the two ends of the base tube 31 are fixedly connected to the two second connectors 20 respectively, the modified carbon fiber bundle impregnated with the impregnation liquid is wound around the outer wall of the base tube 31 and part of the outer wall of the second connector 20. It is heated to 130°C and cured for 3 hours, then heated to 150°C and cured for 4 hours, and finally cured at 80°C for 5 hours to form the inner winding layer 32. A2: Place the two first connectors 10 on the outside of the two second connectors 20 respectively; A3: Modified carbon fiber bundles impregnated with impregnation liquid are wound onto the surface of the inner winding layer 32 and part of the surface of the first joint 10, heated to 130°C and cured for 3 hours, then heated to 150°C and cured for 4 hours, and finally cured at 80°C for 5 hours to form the outer winding layer 34, thus obtaining a non-metallic hydrogen transport pipeline; the rest is the same as in Example 4.

[0073] Test Example 1 Performance tests were conducted on the hydrogen transport pipelines of Examples 2-9 and Comparative Examples 1-2. The instantaneous burst strength (MPa) and airtightness were tested according to GB50177-2005. The leakage resistance test method was as follows: both ends of the hydrogen transport pipeline under test were sealed. Helium gas was injected into the pipeline, then released, and this cycle was repeated 20 times to ensure that the gas in the pipeline was helium. Then, at room temperature, the leakage rate of the hydrogen transport pipeline was measured using a helium mass spectrometer leak detector. The reading of the helium mass spectrometer is the leakage rate of the hydrogen transport pipeline under test. The test results are shown in Table 1.

[0074] Table 1

[0075] As shown in Table 1, the hydrogen transport pipelines in Examples 2-9 include non-metallic pipes. The non-metallic pipes contain a base pipe 31, an inner winding layer 32, a foam layer 33, and an outer winding layer 34. Through the synergistic effect of the base pipe 31, the inner winding layer 32, the foam layer 33, and the outer winding layer 34, not only can the instantaneous burst strength and airtightness of the hydrogen transport pipeline be effectively improved, but the leakage rate of the hydrogen transport pipeline can also be effectively reduced. Compared with the existing technology of directly coating the surface of plastic hydrogen transport pipelines with anti-corrosion coatings, non-metallic hydrogen transport pipelines have higher instantaneous burst strength and airtightness.

[0076] In Comparative Example 1, the non-metallic hydrogen transport pipeline lacks an inner winding layer 32, which reduces the synergistic effect of the base pipe 31, foam layer 33, and outer winding layer 34. The base pipe 31 is directly bonded to the foam layer 33, which has inherent gaps, preventing the concealment of roughness and voids on the surface of the base pipe 31. Similarly, in Comparative Example 2, the non-metallic hydrogen transport pipeline also lacks a foam layer 33, further reducing the synergistic effect of the base pipe 31, inner winding layer 32, and outer winding layer 34. The inner winding layer 32 is directly bonded to the outer winding layer 34, and without the foam layer 33, the rigid stress of the inner and outer winding layers cannot be dispersed, leading to a decrease in the pressure-bearing capacity of the non-metallic hydrogen transport pipeline. Furthermore, the rigid bonding of the inner and outer winding layers 32 and 34 easily creates interlayer micro-gaps, increasing hydrogen permeation channels. Therefore, the non-metallic hydrogen transport pipelines in Comparative Examples 1 and 2 of this application have reduced instantaneous burst strength and airtightness, and increased leakage rate compared to the non-metallic hydrogen transport pipelines in Examples 2-9. Through the above analysis, the inner winding layer 32 and the foam layer 33 play a very important role in the performance of the non-metallic hydrogen transport pipeline. The absence of either layer will reduce the performance of the non-metallic hydrogen transport pipeline and affect its use effect.

[0077] The above description is merely an embodiment of this application, and the scope of protection of this application is not limited to these specific embodiments, but is determined by the claims of this application. Various modifications and variations can be made to this application by those skilled in the art. Any modifications, equivalent substitutions, improvements, etc., made within the technical concept and principles of this application should be included within the scope of protection of this application.

Claims

1. A method for preparing a non-metallic hydrogen transport pipeline, characterized in that, The non-metallic hydrogen transport pipeline includes: Two first connectors, each first connector having a hollow interior forming an air delivery chamber, a first end of the first connector protruding outward to form a connecting part, the connecting part being provided with a connecting hole for connecting to an external connector, and a second end of the first connector protruding outward to form a limiting part; Two second connectors are fixedly connected inside the first connector; A non-metallic tube, comprising, from the inside out, a base tube, an inner winding layer, a foam layer, and an outer winding layer, wherein both ends of the base tube are fixedly connected to two second joints, and both ends of the foam layer are connected to the limiting portions of the two first joints. Includes the following steps: A1: After the two ends of the base tube are fixedly connected to the two second connectors respectively, the modified carbon fiber bundles impregnated with the impregnation liquid are wound around the outer wall of the base tube and part of the outer wall of the second connector. After heating and curing, an inner winding layer is formed. A2: Place the two second connectors on the outside of the two first connectors respectively, cover the surface of the inner winding layer with a foam layer, and place the foam layer between the limiting parts of the two first connectors. A3: Modified carbon fiber bundles impregnated with impregnation liquid are wound around the surface of the foam layer and part of the surface of the first joint. After heating and curing, an outer winding layer is formed to obtain a non-metallic hydrogen transmission pipeline. The method for preparing the modified carbon fiber bundles is as follows: B1: After carbon fiber undergoes oxidation treatment, it is filtered, washed, and dried to obtain pretreated carbon fiber; B2: Mix pretreated carbon fiber with 10-20 times the amount of anhydrous ethanol, add silane coupling agent containing double bonds, the mass ratio of pretreated carbon fiber to silane coupling agent containing double bonds is 1:(1.2-2), mix evenly, heat to 60-70℃ for reaction, filter, wash and dry after reaction to obtain carbon fiber containing double bonds. B3: Carbon fibers containing double bonds, 2-mercapto-4-methylimidazole and anhydrous ethanol are mixed, an inert gas is introduced as a protective gas, a photoinitiator is added, and the reaction is carried out under ultraviolet light with stirring. After the reaction is completed, the solvent is removed, and the mixture is washed and dried to obtain modified carbon fibers. B4: Modified carbon fiber bundles are obtained by spinning and twisting modified carbon fibers.

2. The method for preparing a non-metallic hydrogen transport pipeline according to claim 1, characterized in that, The first connector has a snap-fit ​​groove near the air delivery chamber, and the first end of the second connector protrudes outward to form a snap-fit ​​part, which snaps into the snap-fit ​​groove.

3. The method for preparing a non-metallic hydrogen transport pipeline according to claim 1, characterized in that, The base tube, by mass fraction, comprises: 80-100 parts of polyethylene, 20-30 parts of high-density polyethylene, 20-30 parts of polyethylene-vinyl acetate, 10-20 parts of modified composite filler, and 10-20 parts of compatibilizer. The modified composite filler is obtained by mixing the composite filler with a silane coupling agent and anhydrous ethanol, and then drying it.

4. The method for preparing a non-metallic hydrogen transport pipeline according to claim 3, characterized in that, The compatibilizer includes at least one of polyethylene grafted maleic anhydride and ethylene-vinyl acetate copolymer.

5. The method for preparing a non-metallic hydrogen transport pipeline according to claim 1, characterized in that, The impregnation solution includes polyvinylidene fluoride.

6. The method for preparing a non-metallic hydrogen transport pipeline according to claim 1, characterized in that, The silane coupling agent containing double bonds is at least one of vinyltrimethoxysilane, vinyltriethoxysilane, vinylmethyldimethoxysilane, and vinylmethyldiethoxysilane. The mass ratio of the carbon fiber containing double bonds, 2-mercapto-4-methylimidazole, and anhydrous ethanol is 1:(0.2-0.6):(30-40).

7. The method for preparing a non-metallic hydrogen transport pipeline according to claim 1, characterized in that, The ultraviolet light treatment is divided into two stages. The first stage uses ultraviolet light with a dominant wavelength of 254nm and an irradiance of 10-15mw / cm². 2 Allow the reaction to proceed for 10-20 minutes; The second stage uses ultraviolet light with a dominant wavelength of 365nm and an illuminance of 15-25mw / cm². 2 Allow the reaction to proceed for 30-50 minutes.

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