Device and method for monitoring gas-phase hydrogen permeation of anticorrosive coating

Abstract

The invention discloses an anticorrosive coating gas phase hydrogen permeation monitoring device and method.The anticorrosive coating gas phase hydrogen permeation monitoring device comprises an electrolyte module, a high-voltage module and a potentiometer, the electrolyte module comprises a first barrel and a first flange plate, a boss is arranged on the side, away from the first barrel, of the first flange plate, and a detection hole is formed in the boss; the high-pressure module comprises a second cylinder, a second flange plate and a pressure gauge, the second cylinder is connected with an external hydrogen source pipeline, one end of the second cylinder is connected with the second flange plate, the second flange plate is provided with a placing groove, the placing groove is suitable for placing a sample, and the boss is matched with the placing groove in an inserted mode and abuts against the sample. And through the arrangement of the boss and the placement groove, the potentiometer can conveniently obtain a stable potential signal, so that the hydrogen permeation current density of a unit area is accurately calculated, and the accuracy and comparability of data are ensured.

Description

Technical Field

[0001] This invention relates to the field of material corrosion and protection technology, and in particular to a device and method for monitoring the vapor phase hydrogen permeation of anti-corrosion coatings. Background Technology

[0002] Hydrogen energy is a new type of highly efficient and renewable resource. In the development and utilization of hydrogen energy, whether using existing natural gas pipelines for hydrogen blending and transportation or constructing new hydrogen pipelines for pure hydrogen transportation, the compatibility of materials with the hydrogen environment must be considered. If the anti-corrosion coating inside the pipeline cannot effectively prevent hydrogen permeation, hydrogen atoms will penetrate the inner coating and accumulate at defects in the substrate, leading to hydrogen embrittlement (a sudden drop in material toughness, resulting in sudden fracture), hydrogen blistering (bulging and cracking of the substrate surface), or hydrogen-induced stress corrosion cracking, causing equipment failure and safety accidents. Therefore, hydrogen permeation monitoring tests on anti-corrosion coatings help to detect coating defects in a timely manner, assess the coating's service life, and thus provide reliable protection for the safe operation of equipment. At the same time, the analysis of hydrogen permeation data can also provide important basis for the improvement and optimization of coating materials, promoting the continuous development of anti-corrosion coating technology.

[0003] Currently, the most commonly used method for evaluating the hydrogen permeation performance of coatings is the electrochemical method. This method utilizes the electrochemical changes in the coating during the substrate corrosion failure process and evaluates the hydrogen permeation performance of the coating based on the electrochemical change signals detected by electrochemical detection instruments. However, the hydrogen concentration provided by the electrochemical monitoring method for hydrogen permeation is limited, and it is highly sensitive to the test environment. Changes in external factors can significantly interfere with the detection signal, leading to deviations in the monitoring data and making it difficult to achieve accurate quantitative assessment of hydrogen permeation. Summary of the Invention

[0004] The purpose of this invention is to provide a gas-phase hydrogen permeation monitoring device for anti-corrosion coatings, which has a simple structure and accurate detection.

[0005] To achieve this objective, the present invention adopts the following technical solution: a gas phase hydrogen permeation monitoring device for an anti-corrosion coating, comprising an electrolyte module, a high-voltage module, and a potentiometer. The electrolyte module includes a first cylinder and a first flange. One end of the first cylinder is connected to the first flange. The first flange has a boss on the side opposite to the first cylinder, and the boss has a detection hole. The detection hole penetrates the first flange along the axial direction of the first cylinder. The high-voltage module includes a second cylinder, a second flange, and a pressure gauge. The second cylinder is connected to an external hydrogen source pipeline, and one end of the second cylinder is connected to the... The second flange is connected to the first flange, which has a placement groove and a slot communicating with the placement groove. The placement groove is suitable for placing a sample. The first flange and the second flange are detachably connected. The boss is inserted into the placement groove and abuts against the sample. The detection end of the pressure gauge is inserted into the second cylinder. The potentiometer is connected to an auxiliary electrode, a reference electrode, and a working electrode. The auxiliary electrode and the reference electrode are respectively inserted into the first cylinder, and the detection end of the reference electrode is directly opposite the detection hole. The working electrode limit is located in the slot and connected to the sample.

[0006] Preferably, a pressure relief valve is also installed on the side wall of the second cylinder, and the pressure relief valve is electrically connected to the pressure gauge.

[0007] Preferably, the first cylinder body has a pressure relief hole at one end away from the second cylinder body, and the first cylinder body is detachably connected to an assembly, the assembly being provided with an explosion-proof membrane, the explosion-proof membrane covering the pressure relief hole.

[0008] Preferably, the electrolyte module further includes a plug, with a water inlet at the top of the first cylinder, the plug being installed at the water inlet, and the plug having two mounting ports, the auxiliary electrode and the reference electrode being installed on the plug and passing through the two mounting ports respectively.

[0009] Preferably, the first cylindrical body is a transparent part.

[0010] Preferably, the first flange is provided with a first connecting part on the side opposite to the second cylinder, and the first connecting part is threadedly connected to the first cylinder.

[0011] Preferably, the bottom end of the first cylinder is provided with a drain pipe, and the drain pipe is provided with a drain valve.

[0012] Preferably, the anti-corrosion coating gas phase hydrogen permeation monitoring device further includes a machine base, wherein the first flange is slidably connected to the machine base along the axial direction of the first cylinder, and the second flange is disposed opposite to the first flange and fixedly connected to the machine base.

[0013] Preferably, the second cylinder and the second flange are integrally formed parts.

[0014] The purpose of this invention is to provide a method for monitoring the vapor phase hydrogen permeation of anti-corrosion coatings, which is simple to operate and yields accurate results.

[0015] To achieve this objective, the present invention adopts the following technical solution: a method for monitoring the vapor phase hydrogen permeation of an anti-corrosion coating, implemented using the aforementioned device for monitoring the vapor phase hydrogen permeation of an anti-corrosion coating, comprising: The test sample is placed in the placement slot, the first cylinder is moved so that the boss abuts against the sample, and the first flange and the second flange are connected. Inject alkaline electrolyte into the first cylinder and let it stand for a period of time until the potential detected by the potentiometer tends to stabilize. Hydrogen gas is injected into the second cylinder until the preset pressure is reached; Obtain the steady-state current density corresponding to the preset pressure within a preset time, and calculate the gas phase hydrogen permeation rate based on the steady-state current density.

[0016] The beneficial effects of the present invention are as follows: When the monitoring device is in use, alkaline electrolyte is injected into the first cylinder and high-pressure hydrogen is injected into the second cylinder. When the hydrogen permeates into the electrolytic cell through the coating, it will react with the alkaline electrolyte to generate a hydrogen permeation current. The potentiometer can detect the change and stability of the hydrogen permeation current through the working electrode, and then calculate the amount of hydrogen permeated through the sample. By setting up a boss and a placement groove, on the one hand, the boss is inserted into the placement groove of the second cylinder and abuts against the sample in the placement groove. Through the pre-tightening force connected by the first flange and the second flange, the end face of the boss can press the sample tightly, ensuring that the sample is subjected to uniform force and will not cause local crushing or sealing failure due to skewness. The structure is simple and effectively improves the installation stability of the sample. On the other hand, the electrolyte only makes stable contact with the sample through the opening area of ​​the detection hole, accurately controlling the effective contact area between the electrolyte and the sample. Moreover, the detection hole restricts the large-scale convection of the electrolyte, so that the liquid column from the sample surface to the reference electrode remains stable. The detection end of the reference electrode is directly opposite the detection hole, which makes it easy for the potentiometer to obtain a stable potential signal, truly reflecting the current change generated by the oxidation of hydrogen atoms, thereby accurately calculating the hydrogen permeation current density per unit area, ensuring the accuracy and comparability of the data.

[0017] This invention also discloses a method for monitoring the vapor phase hydrogen permeation of anti-corrosion coatings, which limits the contact area between the electrolyte and the sample and the ion flow path by using bosses and placement grooves. The method is simple to operate and produces accurate results. Attached Figure Description

[0018] Figure 1 This is a schematic diagram of the structure of the anti-corrosion coating vapor phase hydrogen permeation monitoring device according to an embodiment of this application; Figure 2 This is a schematic diagram of the electrolyte module according to an embodiment of this application; Figure 3 This is a schematic diagram of the structure of the second flange according to an embodiment of this application; Figure 4 This is a schematic diagram of the structure of the plug according to an embodiment of this application.

[0019] In the diagram: 1. Electrolyte module; 11. First cylinder; 111. Second connecting part; 112. Drain pipe; 113. Drain valve; 12. First flange; 121. Boss; 1211. Detection hole; 122. First connecting part; 13. Assembly part; 14. Hole plug; 141. Mounting port; 15. First bracket; 151. Slider; 2. High voltage module; 21. Second cylinder; 211. Inlet valve; 212. Exhaust valve; 213. Pressure relief valve; 22. Second flange; 221. Placement slot; 222. Slot; 23. Pressure gauge; 3. Potentiometer; 31. Auxiliary electrode; 32. Reference electrode; 33. Working electrode; 34. Wire; 4. Machine base; 41. Slide rail; 42. Second bracket. Specific Implementation The present invention will now be described in further detail with reference to the accompanying drawings and embodiments. It should be understood that the specific embodiments described herein are merely illustrative of the invention and not intended to limit it. Furthermore, it should be noted that, for ease of description, the accompanying drawings show only the parts relevant to the present invention, and not all of the structures.

[0021] In the description of this invention, unless otherwise explicitly specified and limited, the terms "connected," "linked," and "fixed" should be interpreted broadly. For example, they can refer to a fixed connection, a detachable connection, or an integral part; they can refer to a mechanical connection or an electrical connection; they can refer to a direct connection or an indirect connection through an intermediate medium; they can refer to the internal communication of two components or the interaction between two components. Those skilled in the art can understand the specific meaning of the above terms in this invention based on the specific circumstances.

[0022] In this invention, unless otherwise explicitly specified and limited, "above" or "below" the second feature can include direct contact between the first and second features, or contact between the first and second features through another feature between them. Furthermore, "above," "over," and "on top" of the second feature includes the first feature directly above or diagonally above the second feature, or simply indicates that the first feature is at a higher horizontal level than the second feature. "Below," "below," and "under" the second feature includes the first feature directly below or diagonally below the second feature, or simply indicates that the first feature is at a lower horizontal level than the second feature.

[0023] In the description of this embodiment, the terms "upper," "lower," "right," etc., refer to the orientation or positional relationship shown in the accompanying drawings. They are used only for ease of description and simplification of operation, and do not indicate or imply that the device or element referred to must have a specific orientation, or be constructed and operated in a specific orientation. Therefore, they should not be construed as limitations on the present invention. In addition, the terms "first" and "second" are used only for distinction in description and have no special meaning.

[0024] Reference Figures 1 to 3As shown, a gas-phase hydrogen permeation monitoring device for anti-corrosion coating provided according to an embodiment of this application includes an electrolyte module 1, a high-voltage module 2, and a potentiometer 3. The electrolyte module 1 includes a first cylinder 11 and a first flange 12. The first cylinder 11 is used to hold an alkaline electrolyte (NaOH electrolyte in this embodiment). One end of the first cylinder 11 is connected to the first flange 12. The first flange 12 has a cylindrical boss 121 on the side away from the first cylinder 11. The boss 121 has a detection hole 1211. The detection hole 1211 penetrates the first flange 12 along the axial direction of the first cylinder 11. At this time, the detection hole 1211 is in communication with the interior of the first cylinder 11. High-pressure module 2 includes a second cylinder 21, a second flange 22, and a pressure gauge 23. The second cylinder 21 is coaxial with and opposite to the first cylinder 11. The side wall of the second cylinder 21 is provided with an inlet valve 211 and an exhaust valve 212. The second cylinder 21 is connected to an external hydrogen source pipeline through the inlet valve 211. The end of the second cylinder 21 facing the first cylinder 11 is connected to the second flange 22. The second flange 22 is provided with a placement groove 221 and a retaining groove 222. In this embodiment, the placement groove 221 is a stepped groove communicating with the second cylinder 21, and the retaining groove... 222 is located on the side of the second flange 22 facing the first flange 12. One end of the slot 222 communicates with the placement groove 221, and the other end penetrates part of the side wall of the second flange 22. The placement groove 221 is suitable for placing the sample. In this embodiment, the sample includes a circular pipe base and an anti-corrosion coating applied to one side of the base. The base is made of stainless steel or polymer plastic, etc. The anti-corrosion coating can be selected as fusion-bonded epoxy powder coating (FBE), polyethylene composite lining material, inorganic non-metallic coating (such as ceramic, glass), etc., as needed, and will not be described in detail here. The first flange 12 and the second flange 22 are detachably connected. The boss 121 is inserted into the placement groove 221 and abuts against the sample. The detection end of the pressure gauge 23 is inserted into the second cylinder 21. The potentiometer 3 (data monitoring instrument) is connected to an auxiliary electrode 31, a reference electrode 32, and a working electrode 33 via three wires 34. The auxiliary electrode 31 and the reference electrode 32 are respectively inserted into the first cylinder 11, with the detection end of the reference electrode 32 facing the detection hole 1211. The working electrode 33 is located in the slot 222 and connected to the sample. In some embodiments, the outer peripheral wall of the boss 121 is provided with an annular first sealing ring. After the boss 121 is inserted into the placement slot 221, the first sealing ring abuts against the inner peripheral wall of the placement slot 221 to ensure a seal between the boss 121 and the placement slot 221.

[0025] Understandably, when using the monitoring device, the sample and working electrode 33 are first installed. Then, alkaline electrolyte is injected into the first cylinder 11, ensuring that the electrolyte covers the detection hole 1211. Next, the auxiliary electrode 31 and reference electrode 32 are inserted, and the position of the reference electrode 32 is adjusted so that the detection end of the reference electrode 32 is directly opposite the opening of the detection hole 1211 (the distance from the detection end of the reference electrode 32 to the end face of the first flange 12 opposite to the second flange 22 is controlled between 0-10 mm). The reference electrode 32 is used to provide a stable reference potential, providing a benchmark for the acquisition of hydrogen permeation current signals. The auxiliary electrode 31, the sample, and the reference electrode 32 together constitute a measurement circuit to accurately monitor the potential change generated by the reaction of hydrogen permeation with the electrolyte. After the potential measured by the potentiometer 3 stabilizes, high-pressure hydrogen is injected into the second cylinder 21 until the preset high pressure is reached, and the coating gas phase hydrogen permeation test is performed for the required time. When hydrogen permeates through the sample coating into the electrolytic cell, it reacts with the alkaline electrolyte to generate a hydrogen permeation current. The potentiometer 3 can detect the change and stability of the hydrogen permeation current through the working electrode 33, and then calculate the amount of hydrogen permeated through the sample.

[0026] By setting up the boss 121 and the placement groove 221, on the one hand, the boss 121 is inserted into the placement groove 221 of the second cylinder 21 and abuts against the sample in the placement groove 221. Through the pre-tightening force connected by the first flange 12 and the second flange 22, the step fit between the end face of the boss 121 and the placement groove 221 can press the sample tightly, ensuring that the sample is subjected to uniform force and will not cause local crushing or sealing failure due to skewness. The structure is simple and effectively improves the installation stability of the sample. On the other hand, the electrolyte is in stable contact with the sample only through the opening area of ​​the detection hole 1211. Compared with the traditional electrochemical hydrogen permeation test device, it can accurately control the effective contact area between the electrolyte and the sample, making the current density calculation more accurate. Furthermore, the detection hole 1211 defines a narrow capillary structure for electrolyte flow, restricting large-scale convection of the electrolyte and ensuring a stable liquid column from the sample surface to the reference electrode 32. With the detection end of the reference electrode 32 directly facing the detection hole 1211, errors caused by electrolyte resistance are reduced, ohmic voltage drop is eliminated, and the potentiometer 3 can obtain a stable potential signal, accurately reflecting the current change generated by hydrogen atom oxidation. This allows for precise calculation of the hydrogen permeation current density per unit area, ensuring data accuracy and comparability, and improving test repeatability and accuracy. In addition, compared to traditional flange sealing structures, the boss 121, when sealed and inserted into the placement groove 221, provides better sealing or high-pressure resistance in high-pressure hydrogen environments, ensuring the monitoring device can adapt to coating gas-phase hydrogen permeation experiments under different pressures.

[0027] Reference Figure 1As shown, it can be understood that a pressure relief valve 213 is also installed on the side wall of the second cylinder 21. The pressure relief valve 213 is an automatic pressure relief valve 213 with a built-in control module. The pressure relief valve 213 is connected to the inside of the second cylinder 21 and is electrically connected to the pressure gauge 23.

[0028] By setting up a pressure relief valve 213, when the pressure gauge 23 detects that the pressure inside the second cylinder 21 exceeds the safe pressure, the pressure relief valve 213 receives the overpressure signal and automatically opens to relieve pressure, effectively improving the safety of the detection device.

[0029] Furthermore, a drain pipe 112 is provided at the bottom center of the first cylinder 11, the drain pipe 112 is connected to the inside of the first cylinder 11, and a drain valve 113 is provided on the drain pipe 112.

[0030] By setting up a drain pipe 112 and a drain valve 113, after the test, the operator can directly open the drain valve 113 to discharge the waste liquid without disassembling and emptying the entire first cylinder 11, which further simplifies the operation steps and improves the ease of use of the testing device.

[0031] Reference Figure 1 and Figure 2 As shown, it can be understood that the first flange 12 has a protruding first connecting part 122 on the side opposite to the second cylinder 21. The first connecting part 122 has an external thread, and one end of the first cylinder 11 has an internal thread. The first connecting part 122 and the first cylinder 11 are connected by the internal thread and the external thread.

[0032] By setting the first connecting part 122 to connect the first cylinder 11 and the first flange 12, the structure of the first cylinder 11 is simplified, the sealing performance of the first cylinder 11 is guaranteed, and the operator can easily disassemble the first flange 12 and clean the first cylinder 11, so as to avoid the first cylinder 11 from participating in waste liquid and affecting the subsequent test results, and further improve the accuracy of the test results.

[0033] Furthermore, a second connecting portion 111 protrudes from one end of the first cylinder 11 away from the second cylinder 21. The second connecting portion 111 is provided with a pressure relief hole, which passes through the second connecting portion 111 radially along the first cylinder 11. The first cylinder 11 is connected to an assembly 13, which is inserted into the second connecting portion 111. A second sealing ring is sandwiched between the inner peripheral wall of the assembly 13 and the outer peripheral wall of the second connecting portion 111. The assembly 13 is provided with an explosion-proof membrane, which covers the pressure relief hole.

[0034] By setting a second connection part 111 with an explosion-proof membrane, when the amount of hydrogen penetrating the coating is too large during the test, the pressure inside the first cylinder 11 will rise rapidly. When the pressure inside the first cylinder 11 exceeds the safety pressure of the explosion-proof membrane (less than the bursting pressure of the first cylinder 11), the explosion-proof membrane bursts instantly to quickly release the pressure, thereby avoiding the overpressure bursting of the first cylinder 11, further improving the safety of the detection device and extending the service life of the first cylinder 11.

[0035] Reference Figure 2 and Figure 4 As shown, the electrolyte module 1 also includes a plug 14, which is rectangular in shape when projected onto the horizontal plane. Along the axial direction of the first cylinder 11, the plug 14 has symmetrical stepped structures on both sides. The top of the first cylinder 11 has a rectangular water inlet with a stepped structure. The plug 14 is inserted into the water inlet, and the stepped structures on both sides of the plug 14 overlap the steps of the water inlet. The plug 14 has two mounting ports 141 spaced apart along the axial direction of the first cylinder 11. The auxiliary electrode 31 and the reference electrode 32 are respectively mounted on the plug 14 and pass through the two mounting ports 141. In some embodiments, the outer peripheral wall of the plug 14 is provided with a third sealing ring. After the plug 14 is installed, the third sealing ring abuts against the inner peripheral wall of the water inlet.

[0036] By setting up the water inlet and the plug 14, on the one hand, the operator can remove the plug 14 to expose a large area of ​​water inlet, which is convenient for the operator to add electrolyte in large flow and improve the efficiency of the test; on the other hand, the auxiliary electrode 31 and the reference electrode 32 can be inserted and removed into the mounting port 141 on the plug 14, which can simplify the installation steps of the auxiliary electrode 31 and the reference electrode 32 and facilitate the installation, removal and use of the auxiliary electrode 31 and the reference electrode 32.

[0037] Preferably, the first cylindrical body 11 is a transparent component. In this embodiment, the first cylindrical body 11 is made of tempered glass that does not react with the alkaline electrolyte, and the plug 14 is also made of tempered glass.

[0038] Making the first cylinder 11 transparent allows operators to easily observe the electrolyte level and improves the visibility of the monitoring device. Furthermore, operators can determine if the sample has perforated and failed by observing whether a large number of bubbles rapidly emerge at the detection hole 1211, thus stopping the test in time and avoiding potential hazards.

[0039] Reference Figure 1As shown, it can be understood that the anti-corrosion coating gas phase hydrogen permeation monitoring device also includes a machine base 4. The machine base 4 is connected to a slide rail 41 and a second support 42. The slide rail 41 extends along the axial direction of the first cylinder 11. The bottom end of the first flange 12 is provided with a first support 15. The bottom end of the first support 15 is provided with a slider 151. The slider 151 slides and engages with the slide rail 41, so that the first flange 12 is slidably connected to the machine base 4 along the axial direction of the first cylinder 11. The second flange 22 is arranged opposite to the first flange 12 through the second support 42 and is fixedly connected to the machine base 4.

[0040] By setting up a machine platform 4, which fixes the second flange 22 and guides the first flange 12 to move toward or away from the second flange 22 via a slide rail 41, the first flange 12 and the second flange 22 can be accurately aligned, making it convenient for operators to quickly connect or separate the first flange 12 and the second flange 22, simplifying the loading and unloading steps of the first flange 12, and further improving the ease of use of the monitoring device.

[0041] Preferably, the second bracket 42, the second cylinder 21, and the second flange 22 are integrally formed, and the second cylinder 21 has a pre-reserved connection port for installing the air inlet valve 211, the exhaust valve 212, the pressure relief valve 213, and the pressure gauge 23.

[0042] By machining the second bracket 42, the second cylinder 21, and the second flange 22 as a single unit, the structural stability of the high-voltage module 2 can be effectively improved. Furthermore, the second cylinder 21 and the second flange 22 are highly sealed, which improves the adaptability of the second cylinder 21 to the internal high-pressure environment.

[0043] A method for monitoring the vapor phase hydrogen permeation of an anti-corrosion coating according to an embodiment of this application is implemented using the aforementioned anti-corrosion coating vapor phase hydrogen permeation monitoring device, including: Place the test sample in the placement groove 221, ensuring that the side of the sample coated with the anti-corrosion coating faces the inside of the second cylinder 21. Move the first cylinder 11 so that the boss 121 fits tightly with the inner wall of the mounting groove and abuts against the sample. Connect the first flange 12 and the second flange 22 with bolts. Inject alkaline electrolyte (NaOH solution) into the first cylinder 11. The electrolyte level should be above the detection hole 1211. At the same time, insert the auxiliary electrode 31 and the reference electrode 32 into the mounting port 141 respectively. Adjust the height and direction of the auxiliary electrode 31 and the reference electrode 32 to ensure that the lower end of the auxiliary electrode 31 is in the NaOH solution and that the detection end (probe) of the reference electrode 32 is facing the detection hole 1211. Turn on the power to potentiometer 3 and let it stand for a period of time until the potential detected by potentiometer 3 tends to stabilize; In this circuit, almost no current flows through the reference electrode 32 (high impedance). Therefore, the potential measured by the reference electrode 32 is the stable potential of the solution at that point, unaffected by the voltage drop caused by current flowing through the solution, providing a benchmark for subsequent monitoring of potential changes at the working electrode 33. The detection end of the reference electrode 32 is directly opposite the detection hole 1211 of the boss 121, providing the reference electrode 32 with an electrolyte channel close to the working electrode 33, minimizing measurement errors caused by solution resistance.

[0044] Close the exhaust valve 212, open the inlet valve 211, and inject hydrogen into the second cylinder 21 until the preset pressure is reached, then close the inlet valve 211. In some embodiments, before injecting hydrogen into the second cylinder 21, it is also necessary to simultaneously open the inlet valve 211 and the exhaust valve 212 on the second cylinder 21 and purge the second cylinder 21 with hydrogen 3-5 times to remove air and other impurities from the second cylinder 21, so as to avoid such gases contaminating the hydrogen and affecting the test results.

[0045] Obtain the steady-state current density corresponding to the preset pressure within a preset time, and calculate the gas phase hydrogen permeation rate based on the steady-state current density.

[0046] Specifically, hydrogen atoms that diffuse through the sample coating to one side of the first cylinder 11 lose electrons on the surface of the working electrode 33, are oxidized into hydrogen ions, and release electrons. These electrons form a weak current in the circuit formed by the auxiliary electrode 31 and the working electrode 33, called the hydrogen permeation current. The magnitude of this current directly reflects the number of hydrogen atoms that penetrate the coating from the second cylinder 21 to reach the first cylinder 11. When high-pressure hydrogen gas is introduced into the second cylinder 21, hydrogen begins to diffuse. After a certain period of time (lag time, t)... lag The current in the first cylinder 11 begins to rise, with a lag time (t). lag ) and the thickness of the sample (L) c The current density (Ii) is directly related to the hydrogen diffusion coefficient (D), and the hysteresis time can also be obtained from the hydrogen permeation current-time curve. When diffusion reaches equilibrium, the current reaches its maximum value and remains stable; this current is called the steady-state current density (Ii). ∞ Gas-phase hydrogen permeability (J) ∞ Both steady-state hydrogen permeation flux and gas-phase hydrogen permeation flux (C0 diffusible hydrogen atom concentration) can be calculated from the above parameters, and the specific calculation formulas are as follows: Where n is the number of electrons transferred in the oxidation reaction (in this embodiment, n is 1), and F is the Faraday constant (96485 C / mol).

[0047] It should be noted that in the same batch of experiments, the pipe base blocks all used the same material, with only the coating composition, thickness and other parameters varying. Therefore, the influence of the pipe base blocks on hydrogen resistance can be disregarded. The differences between different test results are the differences between different coatings. This is specifically stated here to avoid misunderstanding.

[0048] It is understandable that the gas phase hydrogen permeation test conducted using the above method is simple to operate, highly safe, and has high monitoring accuracy. It can adapt to the gas phase hydrogen permeation test of coatings under different pressures and is suitable for large-scale application in the coating performance evaluation, coating material improvement and optimization work in hydrogen pipeline engineering construction, and has high universality.

[0049] Obviously, the above embodiments of the present invention are merely examples for clearly illustrating the present invention, and are not intended to limit the implementation of the present invention. Those skilled in the art will be able to make various obvious changes, readjustments, and substitutions without departing from the scope of protection of the present invention. It is neither necessary nor possible to exhaustively describe all embodiments here. Any modifications, equivalent substitutions, and improvements made within the spirit and principles of the present invention should be included within the scope of protection of the claims of the present invention.

Claims

1. A gas-phase hydrogen permeation monitoring device with an anti-corrosion coating, characterized in that, include: An electrolyte module (1) includes a first cylinder (11) and a first flange (12). One end of the first cylinder (11) is connected to the first flange (12). The first flange (12) has a boss (121) on the side away from the first cylinder (11). The boss (121) has a detection hole (1211). The detection hole (1211) passes through the first flange (12) along the axial direction of the first cylinder (11). The high-pressure module (2) includes a second cylinder (21), a second flange (22), and a pressure gauge (23). The second cylinder (21) is connected to an external hydrogen gas source pipeline. One end of the second cylinder (21) is connected to the second flange (22). The second flange (22) is provided with a placement groove (221) and a slot (222) communicating with the placement groove (221). The placement groove (221) is suitable for placing a sample. The first flange (12) is detachably connected to the second flange (22). The boss (121) is inserted into the placement groove (221) and abuts against the sample. The detection end of the pressure gauge (23) is inserted into the second cylinder (21). A potentiometer (3) is connected to an auxiliary electrode (31), a reference electrode (32), and a working electrode (33). The auxiliary electrode (31) and the reference electrode (32) are respectively inserted into the first cylinder (11), and the detection end of the reference electrode (32) is directly opposite the detection hole (1211). The working electrode (33) is located in the slot (222) and connected to the sample.

2. The anti-corrosion coating vapor phase hydrogen permeation monitoring device according to claim 1, characterized in that, The second cylinder (21) is also equipped with a pressure relief valve (213) on its side wall, which is electrically connected to the pressure gauge (23).

3. The anti-corrosion coating vapor phase hydrogen permeation monitoring device according to claim 2, characterized in that, The first cylinder (11) has a pressure relief hole at one end away from the second cylinder (21). The first cylinder (11) is detachably connected to an assembly (13), which is provided with an explosion-proof membrane that covers the pressure relief hole.

4. The anti-corrosion coating gas phase hydrogen permeation monitoring device according to any one of claims 1-3, characterized in that, The electrolyte module (1) also includes a plug (14). The top of the first cylinder (11) is provided with a water inlet. The plug (14) is installed at the water inlet. The plug (14) is provided with two mounting ports (141). The auxiliary electrode (31) and the reference electrode (32) are respectively installed on the plug (14) and pass through the two mounting ports (141).

5. The anti-corrosion coating vapor phase hydrogen permeation monitoring device according to any one of claims 1-3, characterized in that, The first cylindrical body (11) is a transparent part.

6. The anti-corrosion coating vapor phase hydrogen permeation monitoring device according to any one of claims 1-3, characterized in that, The first flange (12) has a first connecting part (122) on the side opposite to the second cylinder (21), and the first connecting part (122) is threadedly connected to the first cylinder (11).

7. The anti-corrosion coating vapor phase hydrogen permeation monitoring device according to any one of claims 1-3, characterized in that, The bottom end of the first cylinder (11) is provided with a drain pipe (112), and a drain valve (113) is provided on the drain pipe (112).

8. The anti-corrosion coating vapor phase hydrogen permeation monitoring device according to claim 1, characterized in that, The anti-corrosion coating gas phase hydrogen permeation monitoring device also includes a machine base (4), the first flange (12) is slidably connected to the machine base (4) along the axial direction of the first cylinder (11), and the second flange (22) is arranged opposite to the first flange (12) and fixedly connected to the machine base (4).

9. The anti-corrosion coating vapor phase hydrogen permeation monitoring device according to claim 1 or 8, characterized in that, The second cylinder (21) and the second flange (22) are integrally formed parts.

10. A method for monitoring the vapor phase hydrogen permeation of an anti-corrosion coating, implemented using the anti-corrosion coating vapor phase hydrogen permeation monitoring device according to any one of claims 1-9, characterized in that, include: Place the test sample in the placement slot (221), move the first cylinder (11) so that the boss (121) abuts against the sample, and connect the first flange (12) and the second flange (22); Inject alkaline electrolyte into the first cylinder (11), let it stand for a period of time until the potential detected by the potentiometer (3) tends to stabilize; Hydrogen gas is injected into the second cylinder (21) until the preset pressure is reached; Obtain the steady-state current density corresponding to the preset pressure within a preset time, and calculate the gas phase hydrogen permeation rate based on the steady-state current density.

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