Method and device for testing hydrogen permeability of high-pressure flexible composite pipe under tensile load

Abstract

The invention relates to the technical field of gas permeability testing, in particular to a method and a device for testing hydrogen permeability of a high-pressure flexible composite pipe under tensile load. The device comprises a hydrogen concentration detection sensor, a nut, a thrust bearing, a pull rod, a stress monitoring sensor, a blind flange, a flange, an organic glass tube and a clamping plate, wherein the blind flange can seal gas in the tube; the clamping plate is used for axially positioning the composite pipe; axial prestress can be applied to the composite pipe by screwing the nut, and the stress monitoring sensor can record a stress value; the hydrogen concentration detection sensor can detect the gas concentration in the organic glass tube. Compared with the existing closest technology, the method has the advantages that the influence of the tensile load on the hydrogen permeability of the full-size high-pressure flexible composite pipe is considered, the test result is closer to the actual working condition, and technical support can be provided for selection and research and development of the hydrogen energy conveying high-pressure flexible composite pipe material.

Description

Technical Field

[0001] The invention relates to the technical field of gas permeability testing, and in particular to a method and a device for testing hydrogen permeability of a high-pressure flexible composite pipe under a tensile load. Background Art

[0002] Hydrogen energy occupies an important position in the future national energy structure. As a core element in the clean energy system, it will play a key role in building a diversified energy supply network. Promoting the development and application of hydrogen energy is one of the key measures to ensure the achievement of carbon neutrality goals. Hydrogen is regarded as a new energy option with great potential in the future. Compared with traditional fossil fuels, its significant features are low environmental pollution, diverse sources and renewable, which has opened up new solutions for mankind to cope with increasingly urgent energy shortages and environmental challenges. However, the efficient storage and transportation of hydrogen energy is the main problem restricting its large-scale application. At present, there are three main ways to store and transport hydrogen energy: gaseous transportation, liquid transportation and solid transportation. The significant advantage of liquid hydrogen transportation is its high volume density, but due to the complexity of low-temperature liquid hydrogen storage technology and high initial investment costs, there are certain challenges. Solid-state transportation is safer, but it is limited by the low hydrogen storage capacity at room temperature, making it difficult to achieve large-scale promotion and application.

[0003] In contrast, hydrogen pipeline transportation can achieve large-scale transportation at the lowest cost. Hydrogen transportation pipes include metal pipes and non-metallic pipes. For hydrogen-containing metal pipelines, a large number of existing studies have shown that the diffusion of hydrogen atoms into metal materials will reduce the plasticity and strength of the material, thereby causing cracking or delayed brittle failure of metal hydrogen pipes. On the contrary, non-metallic pipes have almost no hydrogen embrittlement problems. At the same time, non-metallic pipes have the advantages of long life, good flexibility and earthquake resistance, and are gradually being used in the field of hydrogen transportation. However, the molecular size of hydrogen is very small, and the problem of hydrogen permeation is inevitable when non-metallic pipes are used to transport hydrogen. The accumulation of hydrogen that permeates from the pipe in a limited space will cause great safety hazards. Therefore, before non-metallic hydrogen pipes are put into practical use, their hydrogen permeability needs to be fully tested to clarify the permeability characteristics of non-metallic pipes to hydrogen.

[0004] The existing gas permeability performance test device is basically designed based on the pressure difference method. Its overall structure includes a high-pressure chamber, a permeated hydrogen receiving chamber and a gas detector. The high-pressure chamber and the permeated hydrogen receiving chamber are separated by a non-metallic test piece to be tested. The gas permeability of the material can be calculated by continuously recording the change curve of the hydrogen concentration in the permeated hydrogen receiving chamber and analyzing the change in the permeated hydrogen concentration. In patent CN 116952782, a small-size non-metallic test piece hydrogen permeability performance test device is proposed, and the test results cannot fully reflect the hydrogen permeability performance under full-size working conditions. Therefore, it is necessary to develop a full-size non-metallic pipe hydrogen permeability performance test device. For example, patent CN 114813452 A discloses a full-size non-metallic pipe hydrogen permeability test device. The pipe to be tested is reinforced with a reinforcement, and the test pressure can be significantly increased, which improves the efficiency of the hydrogen permeation test, but the consistency of this test result and the permeation data in actual service remains to be verified. In summary, the hydrogen permeation test technology for small-sized non-metallic materials cannot reveal the actual permeation amount, and the existing full-sized non-metallic pipe hydrogen permeation test equipment does not consider the effect of load on the hydrogen permeation performance of non-metallic full-sized pipelines.

[0005] In view of the above problems, the present invention aims to provide a method and device for testing the hydrogen permeability of a high-pressure flexible composite pipe under a tensile load, so that the test results are more consistent with actual working conditions. Summary of the invention

[0006] The present invention mainly overcomes the shortcomings of the prior art. The purpose of the present invention is to provide a method and device for testing the hydrogen permeability of a high-pressure flexible composite pipe under a tensile load. To achieve the above technical objectives, the present invention adopts the following technical scheme: A method and device for testing the hydrogen permeability of a high-pressure flexible composite pipe under a tensile load, characterized in that it includes:

[0007] The base is provided with a first clamping plate and a second clamping plate; the first clamping plate is provided with an internal threaded hole, and the second clamping plate is provided with a through hole and a clamping groove; the high-pressure flexible composite pipe is provided with a first joint, a second joint, a third flange, a fourth flange and a pipe body, the left end of the first joint is welded with a third flange, and the right end is buckled with the pipe body, and a plexiglass tube is buckled on the surface of the pipe body.

[0008] Furthermore, the fourth flange and the fourth blind flange of the high-pressure flexible composite pipe are fastened and connected by first bolts; the outer diameters of the fourth flange and the fourth blind flange are larger than the inner diameter of the limiting plate and smaller than the inner diameter of the through hole provided in the second clamping plate.

[0009] Furthermore, the third flange of the high-pressure flexible composite pipe is connected to the second blind flange via a second bolt; the second blind flange is provided with a threaded hole and a through hole, and the through hole can accommodate the bolt head of the second bolt.

[0010] Furthermore, the third flange, the second blind flange and the first blind flange are connected by second bolts; the first blind flange is provided with a pull rod, and the external thread provided on the pull rod can cooperate with the internal thread hole provided on the first clamping plate.

[0011] Furthermore, a stress monitoring sensor is placed on the surface of the pull rod located between the first clamping plate and the first blind flange; and a nut and a thrust bearing are installed on the portion of the pull rod located on the left side of the first clamping plate.

[0012] Compared with the prior art, the present invention has the following beneficial effects:

[0013] The test method in the present invention is simple and easy to implement. The strain obtained by the stress monitoring sensor can be used to calculate the numerical value of the axial load. By tightening the nut, the hydrogen permeability coefficient test of the full-size high-pressure flexible composite pipe under the action of the axial load can be realized. The present invention can measure the hydrogen permeability coefficient under different pipe diameters and different gas conditions, and has a wide range of applications. In short, the present invention can realize the study of the permeation law of full-size non-metallic pipes under load, and the test results can provide a technical reference for the design and material selection of non-metallic hydrogen transmission pipes in the future. BRIEF DESCRIPTION OF THE DRAWINGS

[0014] In order to more clearly illustrate the embodiments of the present invention or the technical solutions in the prior art, the drawings required for use in the embodiments or the description of the prior art will be briefly introduced below. Obviously, the drawings described below are only some embodiments recorded in the present invention. For ordinary technicians in this field, other drawings can be obtained based on these drawings without paying creative work.

[0015] Figure 1 This is a schematic diagram of the overall structure of a device for testing hydrogen permeability of a high-pressure flexible composite pipe under a tensile load in an embodiment of the present invention;

[0016] Figure 2 This is a schematic diagram of the base structure of a device for testing hydrogen permeability of a high-pressure flexible composite pipe under a tensile load in an embodiment of the present invention;

[0017] Figure 3 It is a schematic diagram of the installation structure of a high-pressure flexible composite pipe of a device for testing hydrogen permeation performance of a high-pressure flexible composite pipe under tensile load in an embodiment of the present invention;

[0018] Figure numerals: base 1, nut 2, thrust bearing 3, pull rod 4, stress monitoring sensor 5, first blind flange 6, second blind flange 7, third flange 8, first joint 9, plexiglass tube 10, second joint 11, limit plate 12, fourth flange 13, fourth blind flange 14, first bolt 15, second bolt 16, third bolt 17, first clamping plate 18, second clamping plate 19, internal threaded hole 20, clamping groove 21, through hole 22. DETAILED DESCRIPTION

[0019] The technical solutions in the embodiments of the present invention will be described clearly and completely below in conjunction with the drawings in the embodiments of the present invention. Obviously, the described embodiments are only part of the embodiments of the present invention, rather than all the embodiments.

[0020] In the description of the present invention, it should be noted that the orientations or positional relationships indicated by “center”, “up”, “down”, “left”, “right”, “vertical”, “horizontal”, “inside” and “outside”, etc., are based on the orientations or positional relationships shown in the accompanying drawings, and are only for the convenience of describing the present invention and simplifying the description, rather than indicating or implying that the referred device or element must have a specific orientation, be constructed and operated in a specific orientation, and therefore cannot be understood as a limitation on the present invention.

[0021] Example 1

[0022] The present invention provides a method and device for testing the hydrogen permeability of a high-pressure flexible composite pipe under tensile load. The device comprises a base, a card plate, a flange and a sensor assembly, and can simulate the gas permeability of a high-pressure flexible composite pipe under prestressed working conditions. The structure of the device is as follows Figure 1-3 As shown, the specific operation steps are described in detail below:

[0023] First, the base (1) is placed on a horizontal platform to ensure that the device is stable. A first clamping plate (18) and a second clamping plate (19) are provided on the base, wherein the first clamping plate (18) is provided with an internal threaded hole (20), and the second clamping plate (19) is provided with a through hole (22) and a clamping slot (21).

[0024] Specifically, a high-pressure flexible composite pipe is prepared, and the two ends of the pipe body (23) are connected to the first joint (9) and the second joint (11) respectively. The left end of the first joint (9) is welded to the third flange (8) to ensure that the welding is tight and leak-free. The organic glass tube (10) is buckled to the outer surface of the pipe body (23), and the buckled surface is sealed with a high-strength sealant to seal the gas that penetrates from the pipe body (23); at the same time, a gas detection sensor is placed in the annular space formed by the organic glass tube (10) and the pipe body (23), and the signal transmission line on the sensor is led out through the small hole on the surface of the organic glass tube (10), and the gap between them is sealed by glue.

[0025] The fourth flange (13) is connected and fastened to the fourth blind flange (14) by means of the first bolt (15) to seal the right end of the high-pressure flexible pipe. Similarly, the third flange (8) is connected to the second blind flange (7) by means of the second bolt (17) to seal the left end of the high-pressure flexible pipe.

[0026] At this time, it is necessary to ensure that the outer diameter of the fourth flange (13) is larger than the inner diameter of the limiting plate (12), but smaller than the inner diameter of the through hole (22) on the second clamping plate (19), so as to ensure a firm connection and good sealing.

[0027] Specifically, the first blind flange (6) is provided with a through hole for accommodating the bolt head of the second bolt (17), so as to ensure that the surfaces of the first blind flange (6) and the second blind flange (7) can be closely fitted, so that the device structure is more stable. The third flange (8) of the high-pressure flexible composite pipe is connected to the first blind flange (6) through the second bolt (16), which has the advantage that the axial load can be transmitted to the pipe body (23) of the high-pressure flexible composite pipe through the second bolt (16) instead of the third bolt (17), thereby avoiding adverse effects on the sealing between the second blind flange (7) and the third flange (8).

[0028] Specifically, a tie rod (4) is installed on the first blind flange (6), and the external thread on the tie rod is matched with the internal thread hole (20) on the first clamping plate (18). The nut (2) on the tie rod (4) is rotated to gradually apply prestress. In order to reduce friction, the nut (2) and the thrust bearing (3) are installed on the left side of the tie rod, and the axial load is increased by tightening the nut. A stress monitoring sensor (5) is installed between the tie rod (4) and the first clamping plate (18) to monitor the stress value of the pipeline in real time to ensure the accuracy of the test conditions.

[0029] After the prestress loading is completed, the air inlet of the high-pressure flexible composite pipe is connected to the hydrogen bottle, and the exhaust port is connected to the atmosphere; the valve of the hydrogen bottle is opened to introduce hydrogen into the high-pressure flexible composite pipe to replace the air, ensuring that there is only hydrogen inside the pipe body before the permeation experiment begins. Subsequently, the exhaust port of the high-pressure flexible composite pipe is closed, hydrogen is injected into the pipe through the hydrogen bottle and reaches a predetermined pressure, and the air inlet valve is closed. Subsequently, the change curve of the hydrogen concentration in the organic glass tube (10) over time is immediately recorded by the hydrogen detection sensor. According to the data recorded by the sensor, the hydrogen permeability coefficient of the pipe is calculated by analyzing the rate of change of the hydrogen concentration. This process can be repeated under different pressure conditions to measure the gas permeability performance of the high-pressure flexible composite pipe under various working conditions.

[0030] The device is suitable for high-pressure flexible composite pipes of different diameters and lengths. The inner diameter of the cardboard can be adjusted according to the size of the test pipe, so as to meet the testing needs of pipes of different specifications. By replacing the pipe and flange, the hydrogen permeation performance of pipes of different materials and thicknesses can be measured.

[0031] Example 2

[0032] Based on Example 1, the device can be used for permeability testing of different gases (such as nitrogen, helium, etc.). By changing the test gas and adjusting the corresponding sensor parameters, the permeability of different gases can be measured. This test device is not only suitable for hydrogen, but can also be widely used in the transmission pipeline testing of other gases.

[0033] The above shows and describes the basic principles, main features and advantages of the present invention. It should be understood by those skilled in the art that the present invention is not limited to the above embodiments. The above embodiments and descriptions are only for explaining the principles of the present invention. Without departing from the spirit and scope of the present invention, the present invention may have various changes and improvements, which fall within the scope of the present invention to be protected. The scope of protection of the present invention is defined by the attached claims and their equivalents.

Claims

1. A method and device for testing hydrogen permeability of a high-pressure flexible composite pipe under tensile load, characterized in that: include: The base (1) is provided with a first clamping plate (18) and a second clamping plate (19); the first clamping plate (18) is provided with an internal threaded hole (20), and the second clamping plate (19) is provided with a through hole (22) and a clamping groove (21); the high-pressure flexible composite pipe is provided with a first joint (9), a second joint (11), a third flange (8), a fourth flange (13) and a pipe body (23); the third flange (8) is welded to the left end of the first joint (9), and the right end is buckled with the pipe body (23); and an organic glass tube (10) is buckled on the surface of the pipe body (23).

2. The method and device for testing hydrogen permeability of a high-pressure flexible composite pipe under tensile load according to claim 1, characterized in that: The fourth flange (13) and the fourth blind flange (14) of the high-pressure flexible composite pipe are fastened and connected by a first bolt (15); the outer diameters of the fourth flange (13) and the fourth blind flange (14) are larger than the inner diameter of the limiting plate (12) and smaller than the inner diameter of the through hole (22) provided in the second clamping plate (19).

3. The method and device for testing hydrogen permeability of a high-pressure flexible composite pipe under tensile load according to claim 2, characterized in that: The third flange (8) of the high-pressure flexible composite pipe is connected to the second blind flange (7) via a second bolt (17); the second blind flange (7) is provided with a threaded hole and a through hole, and the through hole can accommodate the bolt head of the second bolt (17).

4. The method and device for testing hydrogen permeability of a high-pressure flexible composite pipe under tensile load according to claim 3, characterized in that: The third flange (8), the second blind flange (7) and the first blind flange (6) are connected by a second bolt (16); the first blind flange (6) is provided with a pull rod (4), and the external thread provided on the pull rod (4) can cooperate with the internal thread hole (20) provided on the first clamping plate (18).

5. The method and device for testing hydrogen permeability of a high-pressure flexible composite pipe under tensile load according to claim 4, characterized in that: A stress monitoring sensor (5) is placed on the surface of the pull rod (4) located between the first clamping plate (18) and the first blind flange (6); a nut (2) and a thrust bearing (3) are installed on the part of the pull rod (4) located on the left side of the first clamping plate (18).

6. A method for testing the hydrogen permeability of a high-pressure flexible composite pipe under tensile load, characterized in that: The device for testing the hydrogen permeability of a high-pressure flexible composite pipe under tensile load according to claims 1 to 5 is characterized in that it comprises the following steps: (1) The fourth flange (13) and the fourth blind flange (14) of the high-pressure flexible composite pipe are fastened and connected by means of the first bolt 15, and the third flange (8) and the second blind flange (7) are connected by means of the second bolt (17); the high-pressure flexible composite pipe is purged with high-purity nitrogen gas to remove the air inside the high-pressure flexible composite pipe, and then the high-pressure flexible composite pipe is connected to the high-purity hydrogen cylinder; (2) The first blind flange (6), the third flange (8) and the second blind flange (7) are connected by a second bolt (16), the nut (2) and the thrust bearing (3) are installed on the pull rod (4), the nut (2) is tightened to apply a tensile load to the high-pressure flexible composite pipe, and the stress monitoring sensor (5) records the load value; (3) The organic glass tube (10) is buckled onto the surface of the tube body (23), a hydrogen concentration detection sensor is placed inside the organic glass tube (10), the valve of the hydrogen cylinder is opened and hydrogen is filled into the high-pressure flexible composite tube, and the valve of the hydrogen cylinder is closed after a preset pressure is reached; (4) The hydrogen concentration detection sensor begins to monitor and record the hydrogen permeation concentration of the full-size high-pressure flexible composite pipe under tensile load conditions.

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