Composite pipe for preventing blisters due to hydrogen permeation, its design method, and hydrogen pipeline network

Abstract

The present invention provides a composite pipe for preventing blisters caused by hydrogen permeation, the composite pipe comprising a pipe body, the pipe body having at least two sets of bilayer structures arranged in order from the inside to the outside in the radial direction of the pipe body, the bilayer structures having a barrier layer and a reinforcing layer, the reinforcing layers in each set of bilayer structures being provided outside the barrier layer. The present invention further provides a method for designing the composite pipe and a hydrogen pipeline network including the composite pipe.

Description

Technical Field

[0001] The present invention relates to the technical field of hydrogen pipelines, and in particular, to a composite pipe for preventing blisters due to hydrogen permeation, its design method, and a hydrogen pipeline network. <Cross-reference to Related Applications> The present invention claims the priority of a Chinese patent application with the application number 202310993896.7, filed on August 9, 2023, and the entire disclosure of this application is incorporated herein by reference.

Background Art

[0002] As an important means of transportation, pipeline transportation takes advantage of low cost, high efficiency, long-distance transportation, etc., and is widely used in fields such as energy transportation, chemical industry raw material transportation, and water supply transportation. Pipes for pipeline transportation are generally divided into metal pipes, non-metal pipes, and composite pipes according to the difference in materials. Metal pipes are made of metal, such as steel pipes and stainless steel pipes. Metal pipes can be used in high-pressure environments due to their high-strength characteristics, but they are easily corroded and damaged by the surrounding environment. Non-metal pipes generally include plastic pipes, fiberglass pipes, etc., and have advantages such as low cost and corrosion resistance. However, due to the structure and characteristics of the non-metal pipe material itself, there are problems such as being easily softened, deformed, having a large linear expansion coefficient, and being easily creeped. Currently, the use environment of pipes is more severe, the requirements for pipe performance are higher, and it is difficult for the performance of single-material pipe materials to solve various practical problems. Through composite material technology, composite pipes are manufactured by combining the high strength of metal pipes and the corrosion resistance of non-metal pipes. Composite pipes can integrate the excellent performance of multiple materials and obtain pipes with excellent performance due to complementary material performance. Composite pipes integrate the excellent performance of metal pipes and non-metal pipes, can perform fluid transportation better, and have lower maintenance costs. Therefore, composite pipes are widely used. In order to meet different needs and usage environments, various composite pipes with different materials and performances, such as carbon fiber composite pipes, glass fiber composite pipes, and steel wire wound reinforced composite pipes, have been developed. Among them, the steel wire wound reinforced polyethylene pipe combines the corrosion resistance and wear resistance of the polyethylene pipe with the high-strength characteristics of the steel wire, is much stronger than the pure polyethylene pipe, and at the same time, has only one-eighth of the weight of a steel pipe with the same diameter and the same pressure level, so the transportation cost and installation difficulty of the pipe can be significantly reduced.

Summary of the Invention

[0003] According to a first aspect of the present invention, a composite pipe for preventing blisters due to hydrogen permeation is provided. The composite pipe includes a pipe body, and the pipe body has at least two sets of two-layer structures arranged in order from the inside to the outside in the radial direction of the pipe body. Each set of the at least two sets of two-layer structures has a barrier layer and a reinforcing layer, and the reinforcing layer in each set of the two-layer structures is provided outside the barrier layer.

[0004] The application of the present disclosure has the following beneficial effects. According to the research of the inventors, due to the characteristics that hydrogen molecules are small and easy to permeate, in the process of transporting hydrogen gas through the composite pipe in the related art for a long time, hydrogen gas penetrates into the inside of the composite pipe. Taking the composite pipe in the related art (having two inner and outer polyethylene plastic layers, and a wound steel wire layer is provided between the two polyethylene plastic layers) as an example, after long-term use, hydrogen gas penetrates between the two polyethylene plastic layers, so hydrogen gas accumulates between the outer polyethylene plastic layer and the wound steel wire layer, and the outer polyethylene plastic layer directly bears the pressure, thereby forming a blister phenomenon on the surface of the outer polyethylene plastic layer. After discovering this cause, in the present invention, the inventors propose a technical solution in which a reinforcing layer is provided outside the outer barrier layer, and the barrier layer located on the outer layer is prevented from blistering due to the action of the osmotic pressure of hydrogen gas by the protection of the reinforcing layer (bearing pressure together with the outer barrier layer).

[0005] Optionally, if the pipe body has two sets of the two-layer structures, and the barrier layers in the two sets of two-layer structures are represented by P1 and P2 respectively, and the reinforcing layers in the two sets of two-layer structures are represented by H1 and H2 respectively,

Number

Number

[0006] The hydrogen partial pressure due to the hydrogen gas accumulated inside the composite pipe gradually decreases from the inside to the outside. The thicknesses of the barrier layer and the reinforcing layer in each set of the two-layer structure of the composite pipe are designed, and the thickness of the reinforcing layer and the thickness of the barrier layer have a certain proportional relationship. With the above thickness design, the hydrogen partial pressure received by the barrier layer of each layer is proportional to the thickness (the thick barrier layer receives more hydrogen partial pressure, and the thin barrier layer receives less hydrogen partial pressure). That is, its thickness is designed to match the actual characteristics of the hydrogen partial pressure that gradually decreases from the inside to the outside.

[0007] Optionally, the materials of the barrier layers in the two sets of the two-layer structure are the same, the materials of the reinforcing layers in the two sets of the two-layer structure are the same, and the thicknesses of the barrier layer and the reinforcing layer in each set of the two sets of the two-layer structure satisfy the following formula.

Number

[0008] When two sets of the two-layer structure are provided, the proportional relationship between the thickness of the barrier layer and the thickness of the reinforcing layer in each set of the two-layer structure is designed based on experience. Since the barrier layer located in the inner layer needs to be thicker than the barrier layer located in the outer layer, the ratio of the thicknesses between the two needs to be greater than 1. On the other hand, if the barrier layer located in the outer layer is too thin, the barrier effect against hydrogen gas will be lost. Therefore, in order to avoid the situation where the barrier layer located in the outer layer is too thin, the ratio of the thicknesses between the two needs to be less than 9.

[0009] Optionally, the material of the barrier layer adopts a thermoplastic plastic.

[0010] Optionally, the reinforcing layer adopts steel wires and presents a mesh shape, has a coating layer outside the steel wires, and the material of the coating layer adopts thermoplastic plastic.

[0011] According to a second aspect of the present invention, a hydrogen pipeline network is provided, and the hydrogen pipeline network includes a plurality of sealed and communicated composite pipes for preventing blisters due to hydrogen permeation according to any one of the above technical solutions. Since the hydrogen pipeline network according to the present invention is similar to the inference process of the beneficial effects of the foregoing composite pipe, the description is omitted here.

[0012] According to a third aspect of the present invention, a design method of a composite pipe for preventing blisters due to hydrogen permeation is provided. The composite pipe includes a pipe body, and the pipe body has at least two sets of two-layer structures arranged in order from the inside to the outside in the radial direction of the pipe body. Each set of the at least two sets of two-layer structures has a barrier layer and a reinforcing layer, and the reinforcing layer in each set of the two-layer structures is provided outside the barrier layer. The design method includes: determining the hydrogen pressure value of the composite pipe during use and the nominal diameter of the composite pipe based on the design target of the composite pipe; determining the number of sets of two-layer structures in the composite pipe and the materials of each layer of the two-layer structures based on the hydrogen pressure value and the nominal diameter; tentatively determining the thicknesses of the barrier layer and the reinforcing layer in each set of two-layer structures based on the hydrogen pressure value, the number of sets of two-layer structures, and the materials of each layer of the two-layer structures; verifying the strength of the composite pipe, determining the pass or fail of the composite pipe based on the verification result, and if it passes, completing the design; if it fails, increasing the thicknesses of the barrier layer and the reinforcing layer in each set of two-layer structures based on the verification result and the thicknesses of the barrier layer and the reinforcing layer in each set of two-layer structures determined, and verifying the strength of the composite pipe again.

[0013] Since the design method according to the present invention is similar to the inference process of the beneficial effects of the foregoing composite pipe, the description is omitted here.

[0014] Optionally, when the tubular body has two sets of the two-layer structure, the thicknesses of the barrier layer and the reinforcing layer in each set of the two-layer structure are determined by the following formula:

Number

Number

[0015] Optionally, the thicknesses of the barrier layer and the reinforcing layer satisfy the following formula.

Number

[0016] Optionally, verifying the strength of the composite pipe includes verifying the total strength of the composite pipe and the strength of each set of the two-layer structure. When the burst pressure of the composite pipe is greater than three times the hydrogen pressure value, and the burst pressure of each set of the two-layer structure is greater than three times the hydrogen partial pressure received by the corresponding two-layer structure, it is determined that the composite pipe is qualified.

[0017] These features and advantages of the present invention will be described in detail in the following specific embodiments and the accompanying drawings. Preferred embodiments or means of the present invention are shown in detail with reference to the accompanying drawings, but do not limit the technical solution of the present invention. Also, these features, elements, and components appearing in the following and the accompanying drawings are plural and are represented by different symbols or numbers for convenience, but all represent components having the same or similar configurations or functions.

Brief Description of the Drawings

[0018] Hereinafter, the present invention will be further described with reference to the accompanying drawings.

[0019]

Figure 1

Embodiments for Carrying Out the Invention

[0020] Hereinafter, embodiments of the present invention will be described in detail. Examples of the above embodiments are shown in the accompanying drawings. Here, the same or similar reference numerals represent the same or similar elements, or elements having the same or similar functions. The examples in the embodiments are for explaining the present invention and do not limit the present invention.

[0021] "One embodiment" or "embodiment" or "embodiment form" in this specification means that the specific features, structures, or characteristics described in the embodiment itself can be included in at least one embodiment of the present invention. The appearance of the description "in one embodiment" at each position in the specification does not necessarily refer to the same embodiment.

[0022] In recent years, with the development and utilization of hydrogen energy, pipeline transportation has been applied to the transportation of hydrogen gas as the most economical and energy-saving method to achieve long-distance and large-scale transportation of hydrogen gas. Currently, there are two mainstream research directions for hydrogen transportation by pipeline. One is to mix hydrogen into the existing natural gas pipeline network for transportation, and the other is to lay a pure hydrogen pipeline. Long-distance pure hydrogen pipelines mainly adopt steel pipes at present. According to research, in the process of high-pressure hydrogen gas transportation, hydrogen gradually penetrates into the steel and causes hydrogen embrittlement, resulting in phenomena such as a decrease in the mechanical properties of the steel and hydrogen-induced cracking. In addition to hydrogen embrittlement, the steel pipe itself is subject to external environmental corrosion, and the flexibility of the steel pipe is poor, which is not only inconvenient in the process of production, transportation, and construction, but also difficult to effectively resist damage caused by excessive deformation due to natural disasters such as earthquakes and debris flows. On the other hand, pure polyethylene pipelines can prevent the corrosion and penetration of hydrogen into the pipeline material, but their strength is low and they cannot meet the requirements of high-pressure hydrogen gas transportation.

[0023] To solve the above problems, in related technologies, a method of using a composite pipe to transport high-pressure hydrogen gas over a long distance has been proposed. For example, Chinese Patent Publication CN114396512A discloses a method of using a hydrogen embrittlement prevention metal wire-reinforced composite pipe to transport high-pressure hydrogen gas over a long distance, and its focus is on designing the reinforcing layer of the composite pipe to withstand hydrogen penetration and corrosion. However, in actual applications, it has been found that the above technical solution has blister phenomena in some parts of the pipe body, and there is a large leakage risk in the pipe body, which has become an urgent problem to be solved for the current composite pipe.

[0024] The present invention intends to solve to some extent one of the technical problems in the related art. Therefore, the present invention provides a composite pipe for preventing blisters caused by hydrogen permeation, its design method, and a hydrogen pipeline network.

[0025] Example: This example provides a composite pipe for preventing blisters caused by hydrogen permeation. The composite pipe includes a pipe body, and the pipe body has two two-layer structures arranged in order from the inside to the outside in the radial direction of the pipe body. Each of the two-layer structures has a barrier layer and a reinforcing layer, and the reinforcing layer in each set of two-layer structures is provided outside the barrier layer. As shown in Figure 1, for the convenience of description, in this example, the barrier layer and the reinforcing layer of the two-layer structure closer to the inside of the pipe body among the two sets of two-layer structures are respectively called the inner barrier layer 1 and the inner reinforcing layer 2, and the barrier layer and the reinforcing layer of the two-layer structure closer to the outside of the pipe body among the two sets of two-layer structures are respectively called the outer barrier layer 3 and the outer reinforcing layer 4. The barrier layer in this example adopts a polyethylene material, the reinforcing layer adopts a mesh-shaped steel wire, and a coating layer of PVC material is coated outside the steel wire. In addition, in other embodiments, the barrier layer may adopt a nylon material or other thermoplastic plastic materials, and the coating layer may adopt a PE material or other thermoplastic plastic materials. Also, when manufacturing the composite pipe, a coating layer is coated outside the reinforcing layer, and the coating layer is adhesively fixed to the outer surface of the barrier layer by a hot melt adhesive.

[0026] When the inventors studied the conventional composite pipe, they found that due to the characteristic that hydrogen molecules are small and easy to permeate, in the process of transporting hydrogen gas by the composite pipe in the related technology over a long period of time, hydrogen gas penetrates into the inside of the composite pipe. Taking the composite pipe in the related technology (having two inner and outer polyethylene plastic layers, and a wound steel wire layer is provided between the two polyethylene plastic layers) as an example, after long-term use, hydrogen gas penetrates between the two polyethylene plastic layers, so hydrogen gas accumulates between the outer polyethylene plastic layer and the wound steel wire layer, and the outer polyethylene plastic layer directly bears the pressure, thereby forming a blister phenomenon on the surface of the outer polyethylene plastic layer. After discovering this cause, as a solution to the composite pipe according to this example, the inventors propose a technical solution in which a reinforcing layer is provided outside the outer barrier layer, and the barrier layer located on the outer layer is prevented from blistering due to the action of the osmotic pressure of hydrogen gas by the protection of the reinforcing layer (bearing pressure together with the outer barrier layer).

[0027] In the related art, the thicknesses of the barrier layer located in the inner layer and the barrier layer located in the outer layer of the composite pipe are not particularly designed. Generally, the thickness of the barrier layer located in the inner layer is greater than or equal to the thickness of the barrier layer located in the outer layer. Also, considering the compressive strength, the thicknesses of both are designed to be greater than 3 mm. According to the research results of the applicant of the present invention described above, since the hydrogen gas pressure transmitted through the outer barrier layer is received, such a composite pipe in the related art will have a blister phenomenon on the outer surface after long-term use. A further improvement of the composite pipe according to this embodiment is to analyze the characteristics of the transmitted hydrogen gas pressure and appropriately design the thicknesses of the inner barrier layer 1, the inner reinforcing layer 2, the outer barrier layer 3, and the outer reinforcing layer 4, so that the thickness of each layer structure can withstand the corresponding transmitted hydrogen gas pressure and does not need to be excessively thick (that is, safety is ensured and costs can be controlled). Specifically, when the inner barrier layer 1 is P1, the outer barrier layer 3 is P2, the inner reinforcing layer 2 is H1, and the outer reinforcing layer 4 is H2, the thicknesses of each layer structure satisfy the following requirements.

Number

[0028] The hydrogen partial pressure due to the hydrogen gas accumulated inside the composite pipe gradually decreases from the inside to the outside. The thicknesses of the barrier layer and the reinforcing layer in each set of two-layer structures of the composite pipe are designed, and the thickness of the reinforcing layer and the thickness of the barrier layer have a certain proportional relationship. With the above thickness design, the hydrogen partial pressure received by the barrier layer of each layer is proportional to the thickness (the thick barrier layer receives more hydrogen partial pressure, and the thin barrier layer receives less hydrogen partial pressure). That is, its wall thickness is designed to match the actual characteristics of the hydrogen partial pressure that gradually decreases from the inside to the outside.

[0029] Furthermore, the pipe body has two sets of two-layer structures, and the wall thicknesses of the barrier layer and the reinforcing layer in each set of two-layer structures satisfy the following formula.

Number

[0030] When the pipe body has two sets of two-layer structures, the proportional relationship between the wall thickness of the barrier layer and the reinforcing layer in each set of two-layer structures is designed based on experience. Since the barrier layer (inner barrier layer) of the two-layer structure located inside needs to be thicker than the barrier layer (outer barrier layer) of the two-layer structure located outside, the ratio of the thickness between the two needs to be greater than 1. On the other hand, if the barrier layer located in the outer layer is too thin, the barrier effect against hydrogen gas will be lost. Therefore, in order to avoid the situation where the barrier layer located in the outer layer is too thin, the ratio of the thickness of the inner barrier layer to the thickness of the outer barrier layer needs to be less than 9.

[0031] Hereinafter, taking the design of a hydrogen pipeline network in a certain town as an example, the design process for designing the composite pipe according to this embodiment will be described. Generally, the design includes the following steps S1 to S5 at the time of design.

[0032] In step S1, based on the design target of the composite pipe, the hydrogen pressure value of the composite pipe during use and the nominal diameter of the composite pipe are determined. That is, based on the pressure value required for transporting hydrogen gas in the project, the hydrogen pressure value and the nominal diameter are determined. In this design, the hydrogen pressure value is set to 2 Mpa, and accordingly, the nominal pressure PN of the composite pipe is 2 MPa, and the nominal diameter is 160 mm.

[0033] In step S2, based on the hydrogen pressure value and the nominal diameter, the number of sets and materials of the two-layer structure in the composite pipe are determined. In this design, the number of sets of the two-layer structure is designed to be 2 sets. That is, the composite pipe includes an inner barrier layer 1, an inner reinforcing layer 2, an outer barrier layer 3, and an outer reinforcing layer 4. Also, in this design, both the inner barrier layer 1 and the outer barrier layer 3 adopt a high-density polyethylene material of PE100, and both the inner reinforcing layer 2 and the outer reinforcing layer 4 are mesh-shaped reinforcing layers formed by winding high-strength steel wires. Before winding, the outside of the steel wire is further coated with a coating layer of polyethylene material having hot melt adhesion performance and water shielding effect.

[0034] In step S3, based on the hydrogen pressure value, the number of sets of the two-layer structure, and the materials of each layer of the two-layer structure, the thicknesses of the barrier layer and the reinforcing layer in each set of the two-layer structure are tentatively determined. In this design, the thickness of the inner barrier layer 1 is initially designed to be 15 mm, the thickness of the outer barrier layer 3 is 5 mm, the thickness of the inner reinforcing layer 2 is 3 mm, and the thickness of the outer reinforcing layer 4 is 1 mm. During the initial design, based on experience, a rough range of the total thickness of the composite pipe is determined, and then one value is selected from it as the total thickness of the composite pipe, and the dimensions of each layer structure are roughly determined according to the aforementioned formula

Number

[0035] For example, in this design, assuming that the entire composite pipe adopts a high-density polyethylene material of PE100, in this case, the formula:

Number

[0036] In this step, since σ is the same, the following formula (both sides of the formula are equal to 5) can be satisfied.

Number

Equation

[0037] In step S4, verify the strength of the composite pipe, determine the pass or fail of the composite pipe based on the verification result. If it passes, the design is completed; if it fails, perform step S5.

[0038] In step S5, based on the verification result and the thicknesses of the barrier layer and the reinforcing layer in each set of two-layer structures determined before performing this step, increase the thicknesses of the barrier layer and the reinforcing layer in each set of two-layer structures, and perform step S4 again.

[0039] Specifically, the verification process in step S4 verifies the overall strength of the composite pipe and the strength of each set of two-layer structures. When the burst pressure of the composite pipe (which can represent the compressive strength of the composite pipe) is greater than three times the hydrogen pressure value, and the burst pressure of each set of two-layer structures is greater than three times the hydrogen partial pressure received by the corresponding two-layer structure, it is determined that the composite pipe passes; conversely, it is determined to fail.

[0040] The burst pressure of the composite pipe can be calculated by the following equation.

Equation

[0041] The calculation process of the hydrogen partial pressure corresponding to each two-layer structure will be described below. After the composite pipe has transported hydrogen for a long time and reached a steady state, the pressure of the hydrogen gas gradually decreases from the inside to the outside. Therefore, it is considered that the pressure on the innermost side of the composite pipe is the transportation pressure of the hydrogen gas by the pipeline, and the pressure on the outermost layer of the composite pipe is 0. Since the reinforcing layer has no barrier effect on the hydrogen gas, the pressures of the hydrogen gas on both sides of the reinforcing layer are the same. Since the barrier layer has a barrier effect on the hydrogen gas, the hydrogen pressures on both sides of the barrier layer do not match. As a result, as shown in FIG. 1, there is a pressure difference between the two side surfaces of the two-layer structure close to the inside of the composite pipe (that is, the inner surface of the inner barrier layer 1 and the outer surface of the inner reinforcing layer 2), and there is a pressure difference between the two side surfaces of the two-layer structure close to the outside of the composite pipe (that is, the inner surface of the outer barrier layer 3 and the outer surface of the outer reinforcing layer 4). When calculating the magnitude of the hydrogen partial pressure, it is necessary to consider the permeation coefficient and thickness of the barrier layer material. In this design, the materials of the inner and outer two-layer barrier layers are the same, that is, the permeation coefficients of the materials are the same. The hydrogen gas uniformly penetrates along the radial direction of the composite pipe, that is, it is considered that the hydrogen pressure from the inside to the outside decreases uniformly from 2 MPa (nominal pressure PN) inside to 0. And if the pressure value of the permeated hydrogen gas between the two two-layer structures (that is, between the outer surface of the inner reinforcing layer 2 and the inner surface of the outer barrier layer 3) is F, the nominal pressure FN, the pressure value F of the permeated hydrogen gas between the two two-layer structures, the thickness of the inner barrier layer 1, and the thickness of the outer barrier layer 3 satisfy the following relationship.

Number

[0042] Substituting specific numerical values, F becomes 0.5 MPa. From this, it can be seen that the hydrogen partial pressure received by the two-layer structure close to the inside of the composite pipe is 1.5 MPa, and the hydrogen partial pressure received by the two-layer structure close to the outside of the composite pipe is 0.5 MPa.

[0043] In this embodiment, the burst pressure of the composite pipe obtained by calculation is 6.26 MPa, which is more than three times the nominal pressure (2 MPa). The burst pressure of the two-layer structure near the inside of the composite pipe is 4.85 MPa, the corresponding hydrogen partial pressure is 1.5 MPa, and the burst pressure of the two-layer structure near the inside of the composite pipe is more than three times the corresponding hydrogen partial pressure. The burst pressure of the two-layer structure near the outside of the composite pipe is 1.63 MPa, the corresponding hydrogen partial pressure is 0.5 MPa, and the burst pressure of the two-layer structure near the outside of the composite pipe is more than three times the corresponding hydrogen partial pressure. Therefore, the above design for the thickness of each layer of the composite pipe meets the requirements and passes the verification. Finally, the thicknesses of the four layers from the inside to the outside are designed in the order of 15 mm, 3 mm, 5 mm, and 1 mm. The composite pipe can meet the needs of long-term pipeline high-pressure hydrogen transportation and does not generate blister phenomena due to hydrogen permeation.

[0044] Also, in the requirements of different projects, for example, in another embodiment, the composite pipe is used for the construction of a larger-scale and longer-distance hydrogen pipeline network. In this case, the nominal pressure of the composite pipe is set to 2 MPa, and the nominal diameter is designed to be 355 mm. The two-layer structure is still designed in two sets. The barrier layer located inside adopts a high-density polyethylene material of PE100 (the calculated strength is about 25 MPa), and the barrier layer located outside adopts a PA66 material (the calculated strength is about 75 MPa). The material of the reinforcing layer remains unchanged. In this case, in order to satisfy the formula:

Number

[0045] Verification was carried out by the above method. In this embodiment, the calculated burst pressure of the composite pipe is 7.96 MPa, which is more than three times the nominal pressure (2 MPa). The burst pressure of the two-layer structure close to the inside of the composite pipe is 4.6 MPa, the corresponding hydrogen partial pressure is 1.2 MPa, and the burst pressure of the two-layer structure close to the inside of the composite pipe is more than three times the corresponding hydrogen partial pressure. The burst pressure of the two-layer structure close to the outside of the composite pipe is 4.44 MPa, the corresponding hydrogen partial pressure is 0.8 MPa, and the burst pressure of the two-layer structure close to the outside of the composite pipe is more than three times the corresponding hydrogen partial pressure. Therefore, the above design for the thickness of each layer of the composite pipe meets the requirements and passes the verification. Finally, the thicknesses of the four layers from the inside to the outside are designed in the order of 12 mm, 2 mm, 4 mm, and 2 mm. The composite pipe can meet the needs of long-term high-pressure hydrogen transportation in pipelines and does not generate blister phenomena due to hydrogen permeation.

[0046] Also, in other embodiments, the composite pipe can have at least three sets of two-layer structures. In this way, in the direction from the inside to the outside along the radial direction of the composite pipe, the barrier layers are represented by P1, P2... P n respectively, and the reinforcing layers are represented by H1, H2... H n respectively, then

Number

[0047] The above are only specific embodiments of the present invention, and the protection scope of the present invention is not limited thereto. Those skilled in the art should understand that the present invention includes the content described in the accompanying drawings and the foregoing specific embodiments, but is not limited thereto. Any modification that does not deviate from the functional and structural principles of the present invention shall be included in the scope of the claims.

Explanation of Signs

[0048] 1 Inner barrier layer 2 Inner reinforcing layer 3 Outer barrier layer 4 External Reinforcement Layer

Claims

1. It comprises a tube body, and the tube body has at least two sets of two-layer structures arranged in order from the inside to the outside in the radial direction of the tube body. Each set of the at least two sets of two-layer structures has a barrier layer and a reinforcing layer, and the reinforcing layer in each set of the two-layer structures is provided outside the barrier layer. When the tube body has two sets of the two-layer structures, the thicknesses of the barrier layer and the reinforcing layer in each set of the two-layer structures are determined by the following formula: [Equation 1] P1 and P2 respectively represent the barrier layers in the two sets of the two-layer structures, and H1 and H2 respectively represent the reinforcing layers in the two sets of the two-layer structures. When the tube body has at least three sets of the two-layer structures, the thicknesses of the barrier layer and the reinforcing layer in each set of the two-layer structures are determined by the following formula: [Equation 2] P1, P2...Pn respectively represent the barrier layers in the at least three sets of the two-layer structures, and H1, H2...Hn respectively represent the reinforcing layers in the at least three sets of the two-layer structures. Here, δ is the thickness of the barrier layer or the reinforcing layer, and σ is the calculated strength of the barrier layer or the reinforcing layer. A composite tube for preventing blisters caused by hydrogen permeation, characterized in that.

2. The materials of the barrier layers in the two sets of the two-layer structures are the same, the materials of the reinforcing layers in the two sets of the two-layer structures are the same, and the thicknesses of the barrier layer and the reinforcing layer in each set of the two-layer structures satisfy the following formula: [Equation 3] A composite tube for preventing blisters caused by hydrogen permeation according to Claim 1, characterized in that.

3. The material of the barrier layer employs a thermoplastic. A composite tube for preventing blisters caused by hydrogen permeation according to Claim 1, characterized in that.

4. The reinforcing layer adopts steel wires and presents a mesh shape, has a coating layer outside the steel wires, and the material of the coating layer adopts thermoplastic plastic. The composite pipe for preventing blisters caused by hydrogen permeation according to claim 1, characterized in that.

5. A hydrogen pipeline network comprising a plurality of sealed and communicated composite pipes for preventing blisters caused by hydrogen permeation according to any one of claims 1 to 4. Characterized in that.

6. A design method for a composite pipe for preventing blisters caused by hydrogen permeation, the composite pipe comprising a pipe body, the pipe body having at least two sets of two-layer structures arranged in order from the inside to the outside in the radial direction of the pipe body, each set of the at least two sets of two-layer structures having a barrier layer and a reinforcing layer, and the reinforcing layer in each set of the two-layer structures being provided outside the barrier layer. The design method includes: Based on the design goal of the composite pipe, determining the hydrogen pressure value of the composite pipe during use and the nominal diameter of the composite pipe. Based on the hydrogen pressure value and the nominal diameter, determining the number of sets of two-layer structures in the composite pipe and the materials of each layer of the two-layer structures. Based on the hydrogen pressure value, the number of sets of two-layer structures, and the materials of each layer of the two-layer structures, tentatively determining the thicknesses of the barrier layer and the reinforcing layer in each set of two-layer structures. Verifying the strength of the composite pipe, determining whether the composite pipe is qualified based on the verification result, if it is qualified, the design is completed. If it is unqualified, based on the verification result and the thicknesses of the barrier layer and the reinforcing layer in each set of two-layer structures determined, increasing the thicknesses of the barrier layer and the reinforcing layer in each set of two-layer structures, and verifying the strength of the composite pipe again. A design method for a composite pipe for preventing blisters caused by hydrogen permeation, characterized in that.

7. When the pipe body has two sets of the two-layer structures, the thicknesses of the barrier layer and the reinforcing layer in each set of two-layer structures are determined by the following formula: [Equation 4] P １ and P ２ respectively represent the barrier layers in the two-layer structures of the said two sets, and H １ and H ２ respectively represent the reinforcing layers in the two-layer structures of the said two sets, When the tubular body has at least three sets of the said two-layer structures, the thicknesses of the barrier layer and the reinforcing layer in each set of the two-layer structures are determined by the following formula, 【Equation 5】 P １ , P ２ …P ｎ respectively represent the barrier layers in the at least three sets of the said two-layer structures, and H １ , H ２ …H ｎ respectively represent the reinforcing layers in the at least three sets of the said two-layer structures, Here, δ is the thickness of the barrier layer or the reinforcing layer, and σ is the calculated strength of the barrier layer or the reinforcing layer, A design method for a composite pipe to prevent blisters caused by hydrogen permeation according to claim 6, characterized in that.

8. The thicknesses of the barrier layer and the reinforcing layer satisfy the following formula, 【Equation 6】 A design method for a composite pipe to prevent blisters caused by hydrogen permeation according to claim 7, characterized in that.

9. Verifying the strength of the composite pipe includes verifying the total strength of the composite pipe and the strength of each set of the two-layer structures. When the burst pressure of the composite pipe is greater than three times the hydrogen pressure value, and the burst pressure of each set of the two-layer structures is greater than three times the hydrogen partial pressure received by the corresponding two-layer structure, it is determined that the composite pipe is qualified. A design method for a composite pipe to prevent blisters caused by hydrogen permeation according to claim 6, characterized in that.

10. The material of the barrier layer adopts thermoplastic plastic, The design method of the composite pipe for preventing blisters caused by hydrogen permeation according to claim 6, characterized in that...

11. The reinforcing layer adopts steel wires and presents a mesh shape, and has a coating layer on the outside of the steel wires, and the material of the coating layer adopts thermoplastic plastics. The design method of the composite pipe for preventing blisters caused by hydrogen permeation according to claim 6, characterized in that...

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