A flexible hydrogen transmission pipe, a preparation method thereof, and a hydrogen leakage detection system

Abstract

The present invention belongs to the field of hydrogen transportation, and specifically relates to a flexible hydrogen transmission pipe, a preparation method thereof, and a hydrogen leakage detection system. The flexible hydrogen transmission pipe provided by the present invention adopts a structure mainly made of non-metallic materials, which fundamentally solves the problem of hydrogen embrittlement and improves the safety and reliability of the hydrogen transmission pipe during long-term use. In the present invention, the internal pressure-bearing layer is reinforced with high-strength fibers, which can withstand high internal hydrogen pressure after weaving, ensuring the structural integrity of the pipeline under high-pressure transmission conditions; at the same time, the internal pressure-bearing layer is composited with optical fibers, which can monitor the status of the pipeline to prevent damage by a third party. The optical fiber monitoring system can accurately locate the position of the pipeline in real time and conduct all-round monitoring of the pipeline status, promptly discover potential safety hazards, provide maintenance personnel with accurate fault information, facilitate timely maintenance measures, and reduce accident risks and maintenance costs.

Description

Technical Field

[0001] The present invention belongs to the field of hydrogen transportation, and in particular relates to a flexible hydrogen transmission pipe, a preparation method thereof, and a hydrogen leakage detection system. Background Art

[0002] With the development of the hydrogen energy industry, pipeline hydrogen transportation, as an efficient and economical way of hydrogen transportation, has broad application prospects in both land and marine fields. However, traditional metal hydrogen pipes are prone to hydrogen embrittlement, which leads to pipeline performance degradation or even rupture, posing a major safety hazard. Although some existing non-metallic hydrogen pipes have solved the hydrogen embrittlement problem to a certain extent, most of them lack the ability to accurately locate the pipeline position and real-time monitoring of the pipeline status. They are unable to promptly detect problems such as position offset, damage, and aging that occur during the laying and use of the pipeline, posing a challenge to the safe operation of the hydrogen transmission system. Therefore, it is of great practical significance to develop a flexible hydrogen pipe structure that can effectively avoid hydrogen embrittlement and realize pipeline position positioning and pipeline status monitoring.

[0003] Chinese patent document CN119617201A (202411879198.5) discloses a flexible hydrogen transmission pipeline and a hydrogen leakage detection method, including 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 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 outer side of the inner lining is wrapped with an airtight layer, the outer side of the airtight layer is wrapped with a fiber reinforced inner layer in a forward direction, the outer side of the fiber reinforced inner layer is wrapped with a fiber reinforced outer layer in a reverse direction, and the outer side of the fiber reinforced outer layer is provided with an outer protective layer; a monitoring element is provided in the outer protective layer, and the monitoring element is used to monitor the change in hydrogen concentration or the change in resistance of the outer protective layer in real time. However, the above-mentioned monitoring element is embedded in the outer protective layer and can only monitor the embedded part, but cannot achieve all-round monitoring of the hydrogen pipeline. Summary of the Invention

[0004] The main purpose of the present invention is to provide a flexible hydrogen transmission pipe, a preparation method thereof, and a hydrogen leakage detection system. The flexible hydrogen transmission pipe of the present invention is made of non-metallic materials, which fundamentally avoids the problem of hydrogen embrittlement; at the same time, optical fibers are woven and arranged in the internal pressure-bearing layer to achieve all-round monitoring of the hydrogen transmission pipe, and can achieve precise positioning of the pipeline position and real-time monitoring of the pipeline status, thereby improving the safety and reliability of the hydrogen transmission system and reducing maintenance costs.

[0005] The technical problem to be solved by the present invention is achieved by adopting the following technical solution: a flexible hydrogen transmission pipe, which comprises, from the inside to the outside, an inner lining layer, a barrier layer, an inner pressure-bearing layer, an isolation layer, an outer pressure-bearing layer and an outer protective layer;

[0006] The inner lining layer is made of fluoroplastic material;

[0007] The barrier layer is made of a hydrogen barrier material, and the hydrogen barrier material is a non-metallic material;

[0008] The internal pressure-bearing layer is woven from multiple layers of aramid fiber and optical fiber. Aramid fiber has high strength, high modulus, low density and good fatigue resistance, enabling the hydrogen transmission pipe to withstand various external forces in land and marine environments, including soil pressure, ocean current impact, wave force, etc.

[0009] The outer protective layer is made of a plastic material with good weather resistance and seawater corrosion resistance. The outer protective layer is made of a plastic material with strong weather resistance and abrasion resistance. It has excellent resistance to ultraviolet rays, aging and chemical corrosion, and can adapt to complex and changing outdoor environments or submarine environments, extending the service life of the pipeline.

[0010] One of the key innovations of this invention is the placement of optical fibers within the pipeline. Multiple optical fibers are arranged in parallel with the aramid fibers within the internal pressure-bearing layer. Fiber Bragg grating sensors and distributed fiber optic sensing technologies are integrated into the optical fibers. Fiber Bragg grating sensors can accurately measure parameters such as temperature and strain at specific locations on the pipeline. Distributed fiber optic sensing technology, based on optical time domain reflectometry (OTDR) or optical frequency domain reflectometry (OFDR) technology, can monitor the temperature and strain distribution along the optical fiber in real time. By analyzing and processing this data, the pipeline's location can be accurately calculated and abnormal conditions such as deformation, damage, and leakage can be detected. For example, when a pipeline undergoes local deformation due to external forces, the strain on the optical fiber changes. Distributed fiber optic sensing technology can quickly locate the deformation and assess its extent. When hydrogen leaks, the leaked hydrogen will cause changes in the ambient temperature or pressure. Fiber Bragg grating sensors and distributed fiber optic sensing technologies can work together to promptly sense and accurately locate the leak.

[0011] Since the internal pressure-bearing layer is a woven layer, the isolation layer separates the internal pressure-bearing layer from the external pressure-bearing layer to prevent the internal pressure-bearing layer and the external pressure-bearing layer from rubbing against each other, thereby preventing the internal pressure-bearing layer and / or the external pressure-bearing layer from shrinking and deforming.

[0012] In the present invention, the fluoroplastic material is preferably polytetrafluoroethylene or polyvinylidene fluoride. The inner lining layer is made of fluoroplastics such as polytetrafluoroethylene (PTFE) or polyvinylidene fluoride (PVDF), which have extremely low hydrogen permeability, good chemical stability, and corrosion resistance, effectively preventing hydrogen permeation and corrosion by external chemicals. Furthermore, the smooth inner surface reduces resistance to hydrogen flow.

[0013] In the present invention, the hydrogen barrier material is preferably a nanocomposite material. The barrier layer is made of a nanocomposite material, which significantly improves the barrier performance to hydrogen molecules, greatly reduces the permeation loss of hydrogen, and improves the efficiency and safety of hydrogen transportation.

[0014] Preferably, the braiding angle of the aramid fiber and the optical fiber is 45° to 60°. In order to ensure the tension of the braided layer, the braiding angle of the aramid fiber and the optical fiber is controlled to be between 45° and 60°.

[0015] In the present invention, the isolation layer is preferably made of high-density polyethylene. High-density polyethylene (HDPE) has a softening point of 125-135°C and an operating temperature of up to 100°C. It has better hardness, tensile strength, and creep properties than low-density polyethylene. It also has better wear resistance, electrical insulation, toughness, and cold resistance. It also has good chemical stability and is insoluble in any organic solvents at room temperature. It is resistant to corrosion by acids, alkalis, and various salts.

[0016] Preferably, the external pressure-bearing layer is made of modified polyetheretherketone;

[0017] The external pressure-bearing layer is a pressure-resistant armor layer structure. The external pressure-bearing layer is made of modified PEEK material, which has a certain strength and can withstand a certain amount of external pressure. Setting the external pressure-bearing layer as a pressure-resistant armor layer structure can further enhance the pressure resistance of the external pressure-bearing layer from a structural perspective.

[0018] Preferably, the outer protective layer of the present invention is chloroprene rubber or high-density polyethylene, which has good weather resistance and seawater corrosion resistance, can protect the internal structure from damage by the external environment, prevent ultraviolet radiation, seawater erosion, marine organism attachment and mechanical damage, and extend the service life of the hydrogen transmission pipe.

[0019] The present invention also discloses a method for preparing the flexible hydrogen transmission pipe, comprising the following steps:

[0020] Preparation of the inner lining layer: using the extrusion molding process, the fluoroplastic raw material is heated to a molten state, extruded through a mold to form an inner lining layer pipe, and then cooled with water to set the shape;

[0021] Preparation of barrier layer: Based on the inner liner, the hydrogen barrier material is heated to a molten state by extrusion molding process, and the barrier layer is prepared by extrusion through a die;

[0022] Preparation of the internal pressure-bearing layer: Using a braiding process, aramid fiber and optical fiber are braided on the outside of the barrier layer using a braiding machine at the same time;

[0023] Preparation of the isolation layer: The isolation layer material is coated on the outside of the internal pressure-bearing layer. The isolation layer material is heated to a molten state using an extrusion molding process and extruded through a coating mold to form an isolation layer tube. During the shaping process, vacuum water cooling is performed to prevent the isolation layer material from cooling and shrinking and squeezing into the braided layer of aramid and optical fiber, which would affect the strength of the aramid.

[0024] Preparation of the external pressure-bearing layer: Extruding the external pressure-bearing layer material and the special-shaped cross-section material by melt blending, and winding them on the outside of the isolation layer through a winding machine to form the external pressure-bearing layer;

[0025] Preparation of the outer protective layer: The outer protective layer material is covered on the surface of the external pressure-bearing layer by an extrusion coating process to form the outer protective layer.

[0026] The present invention also discloses a hydrogen leakage detection system, which utilizes the flexible hydrogen transmission pipe and also includes a non-metallic connecting pipe and an optical fiber external connector;

[0027] The end of the flexible hydrogen transmission pipe is installed with a non-metallic connecting pipe fitting, and the non-metallic connecting pipe fitting is provided with an annular sealing groove, and a sealing ring is provided in the annular sealing groove;

[0028] The non-metallic connecting pipes are sealed by bolt connection or socket connection;

[0029] The optical fiber external connector is mounted on a non-metallic connecting pipe and is located outside the annular sealing groove. The optical fiber within the internal pressure-bearing layer is connected to an optical time domain reflectometer or an optical frequency domain reflectometer via the optical fiber external connector. This location ensures a tight seal at the hydrogen transmission pipe connection, preventing hydrogen leakage.

[0030] Preferably, the present invention further comprises an early warning system, and the optical fiber in the internal pressure-bearing layer is connected to the early warning system to provide an early warning of damage to a third party.

[0031] Compared with the prior art, the beneficial effects of the present invention are: the flexible hydrogen transmission pipe provided by the present invention adopts a structure mainly made of non-metallic materials, which fundamentally solves the hydrogen embrittlement problem and improves the safety and reliability of the hydrogen transmission pipe during long-term use.

[0032] In the present invention, the internal pressure-bearing layer is reinforced with high-strength fibers, which can withstand high internal hydrogen pressure after weaving, thereby ensuring the structural integrity of the pipeline under high-pressure transmission conditions; at the same time, the internal pressure-bearing layer is made of composite optical fibers, which can monitor the pipeline status in real time to prevent damage by a third party. The optical fiber monitoring system can accurately locate the pipeline position in real time and comprehensively monitor the pipeline status, promptly discover potential safety hazards, and provide maintenance personnel with accurate fault information, facilitating timely maintenance measures and reducing accident risks and maintenance costs.

[0033] The present invention's lining is made of fluoroplastic material, and the barrier layer is made of hydrogen barrier material, forming a double-layer barrier to hydrogen, with higher hydrogen barrier performance. The double-layer pressure-bearing structure of the internal and external pressure-bearing layers ensures safety during hydrogen transportation.

[0034] The synergistic interaction of the various layers of material in the flexible hydrogen pipe gives it excellent flexibility, high barrier properties, strong pressure bearing capacity, and good environmental adaptability. This flexible hydrogen pipe can be used in both land and marine environments, and has broad market application prospects. BRIEF DESCRIPTION OF THE DRAWINGS

[0035] Figure 1 This is a schematic structural diagram of the flexible hydrogen transmission pipe of the present invention;

[0036] Figure 2 This is a schematic diagram of the braided structure of the internal pressure-bearing layer of the present invention;

[0037] In the figure, 1 is the inner lining layer, 2 is the barrier layer, 3 is the inner pressure-bearing layer, 4 isolating layer, 5 is the outer pressure-bearing layer, and 6 is the outer protective layer;

[0038] 7. Aramid fiber, 8. Optical fiber. DETAILED DESCRIPTION

[0039] The technical solutions in the embodiments of the present invention will be described clearly and completely below with reference to the accompanying drawings in the embodiments of the present invention.

[0040] In an embodiment of the present invention, a flexible hydrogen transmission pipe is provided. The hydrogen transmission pipe has a multi-layer structure and can effectively avoid hydrogen embrittlement. At the same time, optical fibers are arranged along the circumference of the flexible hydrogen transmission pipe through a weaving process, which can effectively detect the pipeline status and prevent third-party damage.

[0041] like Figure 1 and Figure 2 As shown, a flexible hydrogen transmission pipe includes, from the inside to the outside, an inner liner 1, a barrier layer 2, an internal pressure-bearing layer 3, an isolation layer 4, an external pressure-bearing layer 5, and an outer protective layer 6. The inner liner 1, barrier layer 2, internal pressure-bearing layer 3, isolation layer 4, external pressure-bearing layer 5, and outer protective layer 6 are all cylindrical structures.

[0042] The inner lining layer 1 is made of fluoroplastic material.

[0043] The barrier layer 2 is made of a hydrogen barrier material, which is a non-metallic material.

[0044] The internal pressure-bearing layer 3 is woven from multiple layers of aramid fibers 7 and optical fibers 8. The isolation layer 4 is made of non-metallic material.

[0045] The outer protective layer 6 is made of a plastic material with good weather resistance and seawater corrosion resistance. Weather resistance refers to the ability of a material or product to withstand various climatic conditions (such as light, temperature, humidity, wind and rain, etc.) in the natural environment and their effects during long-term use. Weather resistance grade evaluation usually needs to comply with national or international standards, such as ASTM G155, ASTM G154, ISO 4892, etc. These standards specify the requirements for test materials, test conditions, test methods and criteria for judging test results. According to these standards, materials can be quantitatively evaluated and divided into different weather resistance grades, such as good durability, medium durability and poor durability. Those skilled in the art can select the materials used for the outer protective layer based on the corresponding standards. This is a conventional technical means in this field and will not be elaborated here.

[0046] The fluoroplastic material is polytetrafluoroethylene or polyvinylidene fluoride. The inner lining is preferably made of high-purity, low-roughness polytetrafluoroethylene, which has excellent chemical stability and low friction coefficient, can effectively prevent chemical reactions between hydrogen and the inner wall of the pipeline, while reducing hydrogen flow resistance and lowering transportation energy consumption.

[0047] The hydrogen barrier material is a nanocomposite material. The nanocomposite material can be a blend of nylon and polyvinylidene fluoride in the prior art (see Chinese patent document CN114479321B). Those skilled in the art can also select other existing nanocomposite materials according to the performance requirements of the preparation.

[0048] The braiding angle between the aramid fiber 7 and the optical fiber 8 is 45° to 60°.

[0049] The isolation layer 4 is made of high-density polyethylene.

[0050] The external pressure-bearing layer 5 is made of modified polyetheretherketone. The specific modification method is in the existing technology and will not be described in detail here. Those skilled in the art can select the existing modified polyetheretherketone material according to the performance requirements.

[0051] The external pressure-bearing layer 5 is a pressure-resistant armor structure. Specifically, the pressure-resistant armor primarily resists radial forces and is formed by interlocking profiles with cross-sectional shapes such as Z, C, X, T, and F. The pressure-resistant armor is formed by wrapping the profiles around the pipe axis. This provides a strong hoop force to resist high internal pressures, constraining the inner liner and preventing it from bursting. After wrapping, the pressure-resistant armor leaves gaps between adjacent cross-sections, which imparts a certain degree of flexibility to the hose.

[0052] The outer protective layer 6 is made of chloroprene rubber or high-density polyethylene.

[0053] A method for preparing the above-mentioned flexible hydrogen transmission pipe comprises the following steps:

[0054] Preparation of the inner lining layer 1: Using an extrusion molding process, a fluoroplastic raw material is heated to a molten state, extruded through a mold to form an inner lining layer tube, and then cooled with water to set the shape. In this embodiment, the thickness of the inner lining layer tube is 8-10 mm.

[0055] Preparation of barrier layer 2: Using an extrusion molding process, a hydrogen barrier material is heated to a molten state on the basis of the inner liner 1, and then extruded through a die to prepare barrier layer 2. In this embodiment, the melting point of the hydrogen barrier material is 20°C lower than the melting point of the inner liner 1.

[0056] Preparation of the internal pressure-bearing layer 3: Using a braiding process, aramid fiber 7 and optical fiber 8 are braided simultaneously around the barrier layer 2 using a 128-spindle braiding machine. The braided layer is maintained at a certain tension to ensure braid quality and pressure-bearing capacity. In this embodiment, the tension of the internal pressure-bearing layer 3 is above 10N. During the braiding process, care must be taken to avoid excessive stretching or damage to the optical fibers. After braiding, both ends of the optical fibers are connected to a signal processing unit to form a complete optical fiber monitoring network.

[0057] Preparation of the isolation layer 4: The isolation layer material is coated around the internal pressure-bearing layer 3. The isolation layer material is heated to a molten state using an extrusion molding process and then extruded through a coating die to form an isolation layer tube. During the shaping process, the tube is vacuum-cooled and water-cooled to finalize the shape. In this embodiment, the thickness of the isolation layer 4 is 3-5 mm.

[0058] Preparation of the external pressure-bearing layer 5: The external pressure-bearing layer material is extruded by melt blending and extruding the special-shaped cross-section material, and then wound around the outside of the isolation layer 4 by a winding machine to form the external pressure-bearing layer.

[0059] Preparation of the outer protective layer 6: Using an extrusion coating process, the outer protective layer material is applied to the surface of the external pressure-bearing layer 5 to form the outer protective layer. The thickness of the outer protective layer is determined based on the actual use environment and protection requirements to ensure that it effectively protects the internal structure. In this embodiment, the thickness of the outer protective layer 6 is 8-10 mm.

[0060] In the present invention, the extrusion molding process, the extrusion coating process, the weaving process and other processes are all existing technologies, and the specific parameter control will not be repeated here.

[0061] A hydrogen leak detection system utilizes the above-mentioned flexible hydrogen transmission pipe and also includes non-metallic connecting pipes and optical fiber external connectors, which are not shown in the figure. The non-metallic connecting pipes and optical fiber external connectors can adopt pipeline connectors and optical fiber connectors in the existing technology and can be directly purchased and assembled on the market.

[0062] A non-metallic connecting pipe is installed at the end of the flexible hydrogen transmission pipe. The non-metallic connecting pipe is provided with an annular sealing groove, and a sealing ring is provided in the annular sealing groove.

[0063] The non-metallic connecting pipe fittings are sealed by bolt connection or socket connection.

[0064] The optical fiber external connector is provided on the non-metallic connecting pipe fitting, and the optical fiber external connector is located outside the annular sealing groove. The optical fiber in the internal pressure-bearing layer 3 is connected to an optical time domain reflectometer or an optical frequency domain reflectometer via the optical fiber external connector. In this embodiment, the non-metallic connecting pipe fitting is a flange connection or a socket-type connection structure with a sealing rubber ring to ensure the tightness and sealing of the connection and prevent hydrogen leakage. The non-metallic connecting pipe fitting is an existing pipeline connection structure and can be purchased commercially. At the same time, optical fiber sensors are densely arranged near the non-metallic connecting pipe fitting to focus on monitoring the status of the connection part and promptly detect problems such as looseness and leakage that may occur in the connection part.

[0065] Assembly of non-metallic connecting fittings: Install the non-metallic connecting fittings at the ends of the hydrogen transmission pipes and install the sealing rubber rings in the corresponding annular sealing grooves. Then, connect the adjacent hydrogen transmission pipes using bolts or socket joints. After the connection is installed, fiber optic sensors are placed outside the connection and connected to the main fiber optic monitoring network to achieve focused monitoring of the connection.

[0066] The hydrogen leak detection system also includes an early warning system, to which the optical fiber within the internal pressure-bearing layer 3 is connected. This system is a prior art technology that integrates and summarizes optical fiber vibration data, processes this data using a predefined algorithm, and generates graphical information and alarms. For details, see Chinese patent document CN118757683A (202411237180.5).

[0067] The rational selection and design of the materials for each layer of the hydrogen transmission pipe of the present invention make the hydrogen transmission pipe have good flexibility, corrosion resistance, high strength, thermal insulation performance and resistance to environmental interference, and can adapt to various complex application environments such as land and sea.

[0068] The connection structure and optical fiber layout of the hydrogen transmission pipe ensure the reliability and sealing of the pipeline connection, while strengthening the monitoring of the connection parts, further improving the overall safety of the hydrogen transmission system.

Claims

1. A method for preparing a flexible hydrogen transmission pipe, characterized in that: The flexible hydrogen transmission layer comprises, from the inside to the outside, an inner lining layer (1), a barrier layer (2), an inner pressure-bearing layer (3), an isolation layer (4), an outer pressure-bearing layer (5), and an outer protective layer (6); The inner lining layer (1) is made of fluoroplastic material; The barrier layer (2) is made of a hydrogen barrier material, and the hydrogen barrier material is a non-metallic material; The internal pressure-bearing layer (3) is woven from multiple layers of aramid fibers (7) and optical fibers (8); The outer protective layer (6) is made of a plastic material with good weather resistance and seawater corrosion resistance; The following steps are involved: Preparation of the inner lining layer (1): using an extrusion molding process, heating the fluoroplastic raw material to a molten state, extruding it through a mold to form an inner lining layer tube, and using water cooling to shape it; Preparation of the barrier layer (2): using an extrusion molding process, heating the hydrogen barrier material to a molten state on the basis of the lining layer (1), and extruding the barrier layer (2) through a mold; Preparation of the internal pressure-bearing layer (3): using a braiding process, aramid fibers (7) and optical fibers (8) are braided simultaneously on the outside of the barrier layer (2) using a braiding machine, the braiding angle of the aramid fibers (7) and the optical fibers (8) being 45° to 60°, and multiple optical fibers being arranged in parallel with the internal pressure-bearing layer and the aramid fibers, wherein the optical fibers (8) are integrated with fiber Bragg grating sensors and distributed optical fiber sensing technology; Preparation of the isolation layer (4): coating the isolation layer material on the outside of the internal pressure-bearing layer (3), heating the isolation layer material to a molten state by an extrusion molding process, and extruding it through a coating mold to form an isolation layer tube. During the shaping process, vacuum water cooling is performed to shape the tube; Preparation of the external pressure bearing layer (5): The external pressure bearing layer (5) is a pressure-resistant armor layer structure, which is formed by extruding the external pressure bearing layer material and the special-shaped cross-section material by melt blending and extrusion, and winding the material on the outside of the isolation layer (4) through a winding machine, thereby forming the external pressure bearing layer; Preparation of the outer protective layer (6): The outer protective layer material is covered on the surface of the external pressure-bearing layer (5) by an extrusion coating process to form the outer protective layer.

2. The method for preparing a flexible hydrogen transmission pipe according to claim 1, characterized in that: The fluoroplastic material is polytetrafluoroethylene or polyvinylidene fluoride.

3. The method for preparing a flexible hydrogen transmission pipe according to claim 1, characterized in that: The hydrogen barrier material is a nanocomposite material.

4. The method for preparing a flexible hydrogen transmission pipe according to claim 1, characterized in that: The isolation layer (4) is made of high-density polyethylene.

5. The method for preparing a flexible hydrogen transmission pipe according to claim 1, characterized in that: The external pressure-bearing layer (5) is made of modified polyetheretherketone.

6. The method for preparing a flexible hydrogen transmission pipe according to claim 1, characterized in that: The outer protective layer (6) is made of chloroprene rubber or high-density polyethylene.

7. A hydrogen leak detection system, comprising a flexible hydrogen transmission pipe prepared by the method according to any one of claims 1 to 6, characterized in that: Also included are non-metallic connecting pipes and optical fiber external connectors; The end of the flexible hydrogen transmission pipe is installed with a non-metallic connecting pipe fitting, and the non-metallic connecting pipe fitting is provided with an annular sealing groove, and a sealing ring is provided in the annular sealing groove; The non-metallic connecting pipes are sealed by bolt connection or socket connection; The optical fiber external connector is arranged on the non-metallic connecting pipe, the optical fiber external connector is located outside the annular sealing groove, and the optical fiber in the internal pressure-bearing layer (3) is connected to the optical time domain reflectometer or the optical frequency domain reflectometer via the optical fiber external connector; Fiber optic sensors are densely deployed near non-metallic connecting pipes to monitor the status of the connection parts; The optical fiber (8) is integrated with a fiber Bragg grating sensor and a distributed optical fiber sensing technology, which is used to monitor the pipeline status in real time to prevent damage by a third party, locate the pipeline position in real time and accurately, and conduct a comprehensive monitoring of the pipeline status to promptly discover potential safety hazards.

8. The hydrogen leak detection system according to claim 7, characterized in that: It also includes an early warning system, and the optical fiber in the internal pressure-bearing layer (3) is connected to the early warning system.

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