A method and device for measuring hydrogen permeation law of non-metal along thickness direction

Abstract

The present invention relates to the technical field of gas permeability testing, and in particular to a method and device for measuring the hydrogen permeation law of non-metal along the thickness direction. The device comprises a first support base, a hydrogen filling tank, a sample, a hydrogen measuring hose, a hydrogen concentration detector, a second support base, a hydrogen filling hole, a pressure relief hole, a detection hole, an exhaust window, and a sealing O-ring. Hydrogen is filled through the hydrogen filling hole on one side of the hydrogen filling tank, and hydrogen permeates along the thickness direction of the sample according to a concentration gradient. After permeating to the detection hole, hydrogen enters the hydrogen concentration detector through the hydrogen measuring hose. The device can be used to measure the hydrogen permeation law of non-metal along the thickness direction, provide experimental support for related hydrogen permeation simulation, and thus provide a basis for the research, development, and selection of non-metallic materials for hydrogen delivery systems.

Description

Technical Field

[0001] The present invention relates to a method and a device for measuring the hydrogen permeation law of non-metal, and in particular to a method and a device for measuring the hydrogen permeation law of non-metal along the thickness direction. Background Art

[0002] Hydrogen energy is one of the important development directions of new energy, an important way to reduce carbon emissions, and an important energy carrier for my country to achieve the goals of "carbon peak and carbon neutrality". In hydrogen energy storage and transportation technology, using the existing natural gas pipeline network to transport it in the form of hydrogen-blended natural gas can effectively reduce transportation costs. However, due to the gas permeability of non-metallic materials, hydrogen molecules will penetrate non-metallic pipes in hydrogen environments, and their performance will be degraded by the influence of gas permeation coupling, posing risks to engineering applications. Therefore, the ability to measure the laws of non-metallic hydrogen permeation is of great significance to the research and development of non-metallic pipeline materials and the implementation of protection work.

[0003] In the study of hydrogen permeation laws in non-metals, finite element numerical simulation analysis technology is used to reveal the permeation path and concentration distribution law of hydrogen molecules inside non-metals. However, existing experimental methods and detection technologies cannot effectively and in real time detect the permeation path and concentration distribution law of hydrogen molecules along the thickness direction in non-metallic materials. Existing hydrogen permeation experiments can only measure the hydrogen concentration distribution on the surface of the sample.

[0004] In response to the above problems, the present invention aims to propose a method and device for measuring the hydrogen permeation law of non-metals along the thickness direction, providing experimental support for related hydrogen permeation simulations and thus providing a basis for the research, development and selection of non-metallic materials for hydrogen delivery systems. Summary of the Invention

[0005] In order to solve the problem that the prior art cannot measure the permeation path and concentration distribution of hydrogen molecules inside non-metals, the present invention provides a method and device for measuring the hydrogen permeation law of non-metals along the thickness direction.

[0006] The technical solution adopted by the present invention to solve the above problems is: it includes a first support base, a hydrogen filling tank, a sample, a hydrogen measuring hose, a hydrogen concentration detector, and a second support base; detection holes of the same depth are equidistantly distributed on the sample along the thickness direction, and the detection holes are staggered along the thickness direction, thereby reducing changes in the hydrogen permeation behavior of the material caused by the openings; the hydrogen concentration detector is connected to the sample through the hydrogen measuring hose, and the hydrogen measuring hose and the detection hole are sealed by gas sealant, and a hydrogen detection tape is wrapped at the connection between the hydrogen measuring hose and the detection hole to avoid hydrogen concentration measurement errors caused by hydrogen leakage.

[0007] A hydrogen filling tank is welded on the first support seat, and the hydrogen filling tank is filled with an arc column. The arc chord is located below the intersection of the inner diameter of the hydrogen filling tank and the edge detection hole. This can ensure that the penetration area of ​​each detection hole is consistent with the path, and can also reduce the volume of the hydrogen filling tank. A small amount of hydrogen can reach the predetermined pressure; hydrogen filling holes and pressure relief holes are respectively provided on both sides of the hydrogen filling tank, and both the hydrogen filling holes and the pressure relief holes are tapered threaded holes. The hydrogen filling hole is connected to the straight-through air valve, and the pressure relief hole is connected to the three-way air valve with a pressure gauge; a sealing groove is also provided on the hydrogen filling tank for placing a sealing O-ring, and the connection between the sample and the hydrogen filling tank is sealed by a sealing O-ring.

[0008] The second support seat is provided with a circular exhaust window that is consistent with the inner diameter of the hydrogen filling tank. The hydrogen that permeates the sample is discharged through the exhaust window, thereby avoiding reverse penetration of high-concentration hydrogen formed by aggregation; the sample is located between the first support seat and the second support seat. The first support seat and the second support seat are each provided with four corresponding threaded holes and are connected by bolts. Strain gauges are affixed to the bolts, and the strain gauges are connected to the strain measuring instrument. By controlling the force on the bolts, the force applied to the sealing O-ring is evenly distributed, thereby achieving better sealing.

[0009] After assembling the device in the above manner, open the valves on the hydrogen filling hole and the pressure relief hole to introduce hydrogen and discharge the air in the hydrogen filling tank to avoid the problem of inconsistent diffusion area and initial diffusion concentration caused by stratification of the mixed gas. After exhausting, close the valve on the pressure relief hole and fill the hydrogen filling tank with hydrogen at a predetermined pressure. After the hydrogen penetrates into the detection hole, it enters the hydrogen concentration detector through the hydrogen measuring hose. By measuring the hydrogen concentration along the thickness direction at different times, the penetration path and concentration distribution law of hydrogen in the non-metallic material can be obtained. By measuring the change law of hydrogen concentration at the same thickness over time, the permeability coefficient, diffusion coefficient and solubility coefficient of hydrogen in the non-metallic material can also be calculated.

[0010] The beneficial effects of the present invention are:

[0011] 1. The present invention measures the hydrogen permeation law of non-metals along the thickness direction, realizes the non-metal hydrogen permeation test, and then analyzes the diffusion process of hydrogen molecules inside the non-metal and the hydrogen concentration distribution law, providing experimental support for related hydrogen permeation simulation.

[0012] 2. The present invention measures the change pattern of hydrogen concentration at the same thickness of non-metallic samples over time, calculates the permeability coefficient, diffusion coefficient and solubility coefficient of hydrogen in non-metallic materials, and provides a basis for the research, development and selection of non-metallic materials for hydrogen delivery systems. BRIEF DESCRIPTION OF THE DRAWINGS

[0013] In order to more clearly illustrate the embodiments of the present invention or the technical solutions in the prior art, the following briefly introduces the drawings required for describing the embodiments or the prior art.

[0014] Figure 1 Schematic diagram of the overall structure of a method and apparatus for measuring hydrogen permeation law of a non-metal along the thickness direction according to an embodiment of the present invention;

[0015] Figure 2 Schematic diagram of the overall structure of a method and apparatus for measuring hydrogen permeation law of a non-metal along the thickness direction according to an embodiment of the present invention;

[0016] Figure 3 Three views of a specimen and a schematic diagram of the specimen structure of a method and apparatus for measuring hydrogen permeation law of a non-metal along the thickness direction according to an embodiment of the present invention;

[0017] Figure 4 Schematic diagram of the first support structure of a method and apparatus for measuring hydrogen permeation law of non-metal along the thickness direction in an embodiment of the present invention;

[0018] Figure 5 Schematic diagram of the assembly of a first support and a test piece of a method and apparatus for measuring hydrogen permeation law of a non-metal along the thickness direction according to an embodiment of the present invention;

[0019] Figure 6 Schematic diagram of the second support structure of a method and apparatus for measuring hydrogen permeation law of non-metal along the thickness direction in an embodiment of the present invention.

[0020] Figure numerals: It includes a first support base 1, a hydrogen filling tank 2, a sample 3, a hydrogen measuring hose 4, a hydrogen concentration detector 5, a second support base 6, a hydrogen filling hole 7, a pressure relief hole 8, a detection hole 9, an exhaust window 10, and a sealing O-ring 11. DETAILED DESCRIPTION

[0021] Next, the technical solution of the present invention will be described in detail and comprehensively based on the accompanying drawings provided by the embodiments of the present invention. It should be noted that the embodiments described herein are only a part of the many embodiments of the present invention, not the whole picture.

[0022] When describing the present invention, directional terms such as "center," "upper," "lower," "left," "right," "vertical," and "horizontal" are defined with reference to the directions or positions shown in the accompanying drawings. Such expressions are intended to help readers better understand the present invention and simplify the description, and do not imply that the devices or components mentioned must be constructed and operated in a specific direction. Therefore, these terms should not be construed as limiting the scope of the present invention.

[0023] Specific implementation method 1: Combination Figures 1-6This embodiment describes a method and apparatus for measuring hydrogen permeation patterns along the thickness direction of a non-metal. A hydrogen tank 2 is welded to a first support 1, with hydrogen filling holes 7 and pressure relief holes 8 defined on either side. Testing holes 9 are evenly spaced along the thickness direction of a specimen 3. A circular exhaust window 10, identical in diameter to the inner diameter of the hydrogen tank 2, is defined on a second support 6.

[0024] Specific implementation method 2: Combination Figure 1 、 Figure 3 This embodiment describes a method and apparatus for measuring hydrogen permeation behavior along the thickness direction of a non-metal. Adjacent detection holes 9 on a specimen 3 are equidistantly staggered along the thickness direction and perpendicular to the thickness direction, at distances L and x, respectively, to minimize changes in the material's hydrogen permeation behavior caused by the holes. A hydrogen concentration detector 5 is connected to the specimen 3 via a hydrogen detection hose 4. The hose 4 and detection holes 9 are sealed with a gas sealant, and hydrogen detection tape is wrapped around the connection between the hose 4 and the detection holes 9 to minimize hydrogen concentration measurement errors caused by hydrogen leakage.

[0025] Specific implementation method three: Combination Figure 4 、 Figure 5 This embodiment describes a method and apparatus for measuring hydrogen permeation patterns in a non-metallic material along its thickness. A hydrogen tank 2 is welded to a first support base 1. The tank 2 is filled with an arc column, with the arc chord located below the intersection of the inner diameter of the tank 2 and the edge detection hole 9. This ensures that the permeation area of ​​each detection hole 9 is consistent with the path, while also reducing the volume of the hydrogen tank. A small amount of hydrogen can be used to reach a predetermined pressure. A hydrogen charging hole 7 and a pressure relief hole 8 are respectively provided on either side of the hydrogen tank 2. Both the hydrogen charging hole 7 and the pressure relief hole 8 are tapered threaded holes. The hydrogen charging hole 7 is connected to a straight-through air valve, and the pressure relief hole 8 is connected to a three-way air valve with a pressure gauge.

[0026] Specific implementation method four: Combination Figure 2 、 Figure 4 、 Figure 6 This embodiment describes a method and apparatus for measuring hydrogen permeation patterns along the thickness direction of a non-metal. The hydrogen tank 2 also includes a sealing groove for receiving a sealing O-ring 11. The connection between the sample 3 and the hydrogen tank 2 is sealed by the sealing O-ring 11. The sample 3 is positioned between the first support 1 and the second support 6. The first and second support 6 each have four corresponding threaded holes and are connected by bolts. Each bolt is affixed with a strain gauge, which is connected to a strain gauge. By controlling the force on the bolt, the force applied to the sealing O-ring 11 is evenly distributed, thereby achieving a better seal.

[0027] Specific implementation method five: Combination Figure 6This embodiment describes a method and apparatus for measuring hydrogen permeation patterns along the thickness direction of a non-metal. A circular exhaust window 10, which corresponds to the inner diameter of the hydrogen tank 2, is provided on the second support 6. Hydrogen that permeates the sample 3 is discharged through the exhaust window 10, thereby preventing reverse permeation due to accumulation of high-concentration hydrogen.

[0028] The working principle is that the present invention measures the hydrogen concentration along the thickness direction at different times to obtain the hydrogen penetration path and concentration distribution law in non-metallic materials, which is used to support related simulation research.

[0029] The present invention calculates the permeability coefficient, diffusion coefficient, and solubility coefficient of non-metallic materials by measuring the time-dependent variation of hydrogen concentration at a constant thickness. The permeation behavior of gas molecules in non-metallic materials can be simply described as gas molecules being adsorbed or dissolved on the high-pressure side wall, permeating the non-metallic material according to the concentration gradient, and desorbing or evaporating on the other side wall. In other words, the permeation process is decomposed into the dissolution of gas molecules at the gas-solid interface and the diffusion of hydrogen molecules within the non-metallic material. The relationship between the three is expressed as follows:

[0030] P=DS (1)

[0031] Where: P is the permeability coefficient, which refers to the volume of gas that passes through a material of unit thickness per unit time and per unit area under unit pressure difference, and the unit is (m 3 ·m) / (m 2 ·s·Pa);

[0032] D is the diffusion coefficient, which represents the dynamic characteristics between gas molecules and materials, and the unit is m 2 / s;

[0033] S is the solubility coefficient, which represents the thermodynamic properties between gas molecules and materials, and its unit is m 3 / (m 3 ·Pa).

[0034] The hydrogen permeability coefficient is calculated by formula (2):

[0035]

[0036] Where: c is the measured gas mass concentration, in g / m 3 ;

[0037] V is the volume of the detection pore, in m 3 ;

[0038] ρ is the gas density in g / m 3 ;

[0039] T0 and T are the temperature under standard conditions and the experimental temperature, respectively, in K;

[0040] d represents the material thickness, in m;

[0041] A is the permeable area, in m 2 ;

[0042] t is the experimental time, in seconds;

[0043] P1-P2 is the pressure difference on both sides of the sample, in Pa.

[0044] The diffusion coefficient was calculated using the permeation lag time method:

[0045]

[0046] Where: t represents the penetration lag time, which is related to the material thickness and the unit is s.

[0047] Then the solubility coefficient of the material is calculated according to formula (1).

[0048] The test steps are as follows: Figure 1 After assembly, open the valves on the hydrogen filling hole 7 and the pressure relief hole 8 to allow hydrogen to pass for 10 minutes to exhaust the air in the hydrogen filling tank 2, avoiding the problem of inconsistent diffusion area and initial diffusion concentration caused by stratification of the mixed gas. After exhausting, close the valve on the pressure relief hole 8 and fill the hydrogen filling tank 2 with hydrogen greater than 1atm. The hydrogen penetrates into the detection hole 9 and enters the hydrogen concentration detector 5 through the hydrogen measuring hose 4. By measuring the hydrogen concentration along the thickness direction at different times, the permeation path and concentration distribution pattern of hydrogen in non-metallic materials can be obtained. By measuring the change pattern of hydrogen concentration over time at the same thickness, the permeability coefficient, diffusion coefficient and solubility coefficient of the non-metallic material can be calculated. This provides experimental support for related hydrogen permeation simulations and provides a basis for the research and development and selection of non-metallic materials for hydrogen delivery systems.

Claims

1. A device for measuring hydrogen permeation characteristics of non-metals along the thickness direction, characterized by: It comprises a first support base (1), a hydrogen filling tank (2), a sample (3), a hydrogen measuring hose (4), a hydrogen concentration detector (5), and a second support base (6); the first support base (1) is welded with a hydrogen filling tank (2), and hydrogen filling holes (7) and pressure relief holes (8) are respectively provided on both sides of the hydrogen filling tank (2); detection holes (9) are equidistantly distributed along the thickness direction on the sample (3); the second support base (6) is provided with a circular row of holes (9) having the same inner diameter as the hydrogen filling tank (2). Air window (10); a hydrogen filling hole (7) and a pressure relief hole (8) are respectively provided on both sides of the hydrogen filling tank (2); the hydrogen filling hole (7) and the pressure relief hole (8) are both tapered threaded holes; the hydrogen filling hole (7) is connected to a straight-through air valve, and the pressure relief hole (8) is connected to a three-way air valve with a pressure gauge; a sealing groove is also provided on the hydrogen filling tank (2) for placing a sealing O-ring (11); the connection between the sample (3) and the hydrogen filling tank (2) is sealed by the sealing O-ring (11); Detection holes (9) of the same depth are opened on the sample (3), and the detection holes (9) are equidistantly staggered along the thickness direction and the perpendicular thickness direction; the hydrogen concentration detector (5) is connected to the sample (3) through a hydrogen detection hose (4), and the hydrogen detection hose (4) and the detection hole (9) are sealed by a gas sealant, and a hydrogen detection tape is wrapped around the connection between the hydrogen detection hose (4) and the detection hole (9); A hydrogen filling tank (2) is welded on the first support seat (1), and the hydrogen filling tank (2) is filled with an arc column, and the arc column chord is located below the intersection of the inner diameter of the hydrogen filling tank (2) and the edge detection hole (9); a circular exhaust window (10) that is consistent with the inner diameter of the hydrogen filling tank (2) is opened on the second support seat (6), and hydrogen that permeates the sample (3) is discharged through the exhaust window (10); The sample (3) is located between the first support seat (1) and the second support seat (6). The first support seat (1) and the second support seat (6) are each provided with four corresponding threaded holes and are connected by bolts. The bolts are each affixed with strain gauges, and the strain gauges are connected to the strain measuring instrument.

2. A detection method based on the device for measuring hydrogen permeation law of non-metal along the thickness direction according to claim 1, characterized in that: The detection steps are as follows: after assembling the device, open the valves on the hydrogen filling hole (7) and the pressure relief hole (8) to introduce hydrogen for 10 minutes, exhaust the air in the hydrogen filling tank (2), close the valve on the pressure relief hole (8) after exhausting, fill the hydrogen filling tank (2) with hydrogen at a predetermined pressure greater than 1atm, and detect the hydrogen concentration by a hydrogen concentration detector (5); by measuring the hydrogen concentration along the thickness direction at different times, the permeation path and concentration distribution law of hydrogen in the non-metallic material are obtained; by measuring the change law of hydrogen concentration in the same detection hole (9) over time, the permeability coefficient, diffusion coefficient and solubility coefficient of the non-metallic material are calculated, and the relationship between the three is expressed as follows: P=DS (1) Where: P is the permeability coefficient, unit is (m 3 ·m) / (m 2 ·s·Pa); D is the diffusion coefficient, in m 2 / s; S is the solubility coefficient, in m 3 / (m 3 ·Pa); The calculation formula of permeability coefficient P is: Where: c is the measured gas mass concentration, in g / m 3 ; V is the volume of the detection pore, in m 3 ; ρ is the gas density in g / m 3 ; T0 and T are the temperature under standard conditions and the experimental temperature, respectively, in K; d represents the material thickness, in m; A is the permeable area, in m 2 ; t is the experimental time, in seconds; P1-P2 is the pressure difference on both sides of the sample, in Pa; The diffusion coefficient was calculated by the penetration lag time method, and then the solubility coefficient of the material was calculated according to formula (1).

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