High-temperature and high-pressure hydrogen permeation measuring device and measuring method

Abstract

The invention discloses a high-temperature and high-pressure hydrogen permeation measuring device and a measuring method. The high-temperature and high-pressure hydrogen permeation measuring device comprises a hydrogen charging kettle, a hydrogen measuring kettle containing a NaOH solution, a gas charging kettle and a sample module, a first pressure gauge and a thermocouple are arranged at the left end of the hydrogen charging kettle, a heating resistance wire is arranged in the kettle wall of the hydrogen charging kettle, the thermocouple and the heating resistance wire are electrically connected with a temperature controller, and the hydrogen charging kettle is communicated with a high-pressure hydrogen cylinder; a counter electrode and a high-voltage reference electrode are arranged on the hydrogen measuring kettle; a right connecting pipe is arranged on the hydrogen charging kettle, a left connecting pipe is arranged on the hydrogen measuring kettle, the sample module is located in annular grooves in the opposite end faces of the left connecting pipe and the right connecting pipe, and the liquid level of the NaOH solution is higher than the position of the left connecting pipe; the device has the characteristics that hydrogen permeation measurement can be carried out on the austenitic stainless steel under high-temperature and high-pressure conditions, and the measurement stability is good.

Description

Technical Field

[0001] This invention relates to the field of hydrogen energy material safety evaluation and testing technology, and in particular to a high-temperature and high-pressure hydrogen permeation measurement device and method. Background Technology

[0002] Austenitic stainless steel, due to its face-centered cubic (FCC) crystal structure, high toughness, excellent resistance to hydrogen embrittlement, and good weldability, is widely used in critical pressure-bearing components such as hydrogen pipelines, valves, flanges, tank linings, and hydrogenation reactor shells. However, the FCC structure results in its high solubility for hydrogen and low diffusion coefficient.

[0003] Existing hydrogen permeation testing technologies, including electrochemical methods, gas chromatography, and thermal desorption spectroscopy, are all insufficient to meet the combined requirements of high sensitivity and high reliability in real-world environments.

[0004] The electrochemical hydrogen charging method involves sandwiching the sample between two electrolytic cells, with hydrogen charging at the cathode on one side and current density measured at the anode on the other. Its advantages are high sensitivity and fast response; however, the hydrogen charging environment is an aqueous solution, which is inconsistent with the actual gaseous hydrogen environment, making it impossible to apply high pressure, and the temperature is limited by the boiling point of the electrolyte.

[0005] In addition, electrochemical detection requires isolating high-temperature samples from low-temperature electrolytes; otherwise, the electrolytes may easily vaporize, causing the electrodes to fail.

[0006] Gas chromatography uses high-pressure hydrogen to directly purge the hydrogen, and the detection end is purged with carrier gas or vacuum accumulation. The hydrogen concentration is then detected by a gas chromatograph. Although it can simulate real working conditions, it has problems such as system complexity, slow response, and signal lag caused by adsorption and retention in the pipeline.

[0007] Thermal desorption spectroscopy (TDS) measures the total hydrogen content released by heating, but cannot obtain dynamic flux; even if the detection problem is solved, the reliability of the seal under high temperature and high pressure remains a challenge.

[0008] Existing rubber O-rings and PTFE gaskets decompose at temperatures above 200°C, releasing impurities such as CH4 and CO, which contaminate hydrogen gas. Summary of the Invention

[0009] The purpose of this invention is to overcome the shortcomings of existing technologies in achieving both high-temperature detection sensitivity and sealing reliability, and to provide a high-temperature and high-pressure hydrogen permeation measurement device and method.

[0010] To achieve the above objectives, the present invention adopts the following technical solution:

[0011] A high-temperature, high-pressure hydrogen permeation measuring device includes a hydrogen filling vessel, a hydrogen measuring vessel containing NaOH solution, a gas filling vessel, and a sample module. The hydrogen filling vessel has a first pressure gauge and a thermocouple at its left end. A heating resistance wire is installed inside the vessel wall. The thermocouple and heating resistance wire are electrically connected to a temperature controller. The hydrogen filling vessel is connected to a high-pressure hydrogen cylinder. The hydrogen measuring vessel has a counter electrode and a high-pressure reference electrode. The hydrogen filling vessel has a right connecting pipe, and the hydrogen measuring vessel has a left connecting pipe. The sample module is located in an annular groove on the opposite end faces of the left and right connecting pipes. The NaOH solution level is higher than the position of the left connecting pipe. The left and right connecting pipes are detachably and sealed. The gas filling vessel has a second pressure gauge and is connected to a high-pressure nitrogen cylinder. The gas filling vessel is connected to the upper part of the hydrogen measuring vessel via a gas guide pipe. The value obtained by subtracting the volume occupied by the NaOH solution from the volume inside the hydrogen measuring vessel is called W, and W is greater than the volume of the gas filling vessel. The sample module, the counter electrode, and the high-pressure reference electrode are all electrically connected to an electrochemical workstation.

[0012] The hydrogen filling vessel is used to hold high-pressure hydrogen gas, simulating the real high-temperature and high-pressure gaseous hydrogen working conditions; the lid and the horizontal vessel body of the hydrogen filling vessel are arranged side by side, and the lid and the vessel body are tightly connected.

[0013] Due to limitations in the manufacturing technology of high-voltage reference electrodes, excessively rapid gas filling or venting will prevent the gas from entering or escaping through the porous ceramic in a timely manner, causing an imbalance between the internal and external pressures of the reference electrode and resulting in damage to the high-voltage reference electrode. Therefore, this invention provides a gas filling vessel, which is used to gradually and slowly fill the hydrogen measuring vessel with high-pressure inert gas. An O-ring is provided between the vessel body and the vessel cover of the gas filling vessel, and they are fastened together by studs and nuts.

[0014] The sample module is used to place the sample and connects the hydrogen permeation device to the hydrogen charging vessel, which is isolated from the high-temperature and high-pressure hydrogen measuring vessel, and the high-pressure hydrogen measuring vessel.

[0015] The hydrogen measurement vessel includes a vessel body, a vessel lid, and three electrodes, used to measure hydrogen permeation current. The vessel body contains NaOH solution and high-pressure inert gas. The high-pressure inert gas is used to balance the high-temperature and high-pressure hydrogen pressure on the left side of the sample module, thereby reducing the pressure difference on both sides of the sample module.

[0016] The three electrodes include a working electrode, a counter electrode, and a high-voltage reference electrode, with the sample module serving as the working electrode; the counter electrode and the high-voltage reference electrode are connected to the lid of the hydrogen measurement vessel via fixing bolts.

[0017] Insulating rubber sleeves are installed between the electrodes and the high-pressure fixing bolts to prevent electrical conduction between the electrodes and the vessel lid, which would interfere with the accuracy of the electrochemical signal. The three electrodes are connected to the electrochemical workstation via wires. They are connected to the gas-filling vessel via a gas inlet pipe for the filling and venting of high-pressure nitrogen. An O-ring is installed between the vessel body and the vessel lid, and they are fastened together with studs and nuts. The interior of the vessel body and all interfaces connected to it are covered with a corrosion-resistant coating to enhance the stability of long-term service.

[0018] The hydrogen-filling reactor is equipped with a base at the bottom to support the reactor body and to provide thermal insulation between the high-temperature reactor body and the surrounding environment during the test.

[0019] The gas delivery pipe is connected to the gas filling port of the hydrogen filling vessel and the hydrogen measuring vessel by bolts at both ends. The bolts are hollow with external threads. The pipe has external threads on both sides. The gas delivery pipe is passed through the through hole in the middle of the bolt, and then the nut is screwed onto the pipe thread to fix the gas delivery pipe and the bolt. Finally, the bolt is tightened onto the vessel cover.

[0020] Preferably, the sample module includes a left outer shell and a right outer shell, both of which include annular side plates and annular surrounding plates disposed on the inner side of the annular side plates; a left metal sealing ring, a left gasket ring, a disc-shaped sample, a right gasket ring, and a right metal sealing ring are provided between the annular side plates of the left and right outer shells; the left and right outer shells, the left gasket ring, and the right gasket ring are all made of ceramic material, and the cross-sections of the left and right metal sealing rings are both C-shaped with inward opening; the disc-shaped sample is electrically connected to the electrochemical workstation through a wire passing through the left outer shell.

[0021] The hollow outer shell is used to isolate electrical conductivity and reduce the impact of heat conduction between the disc-shaped sample and the vessel body; the metal sealing ring has elastic deformation capability, a C-shaped cross-section, and self-reinforcing sealing properties: the higher the internal pressure, the greater the sealing force, and it is reusable. The disc-shaped sample is sandwiched between two gasket rings, which effectively isolate electrical conductivity and reduce heat conduction.

[0022] Place the left metal sealing ring, the left gasket ring, and the circular sample into the left outer shell in sequence, so that the left metal sealing ring is located at the angle between the annular side plate and the annular surrounding plate of the left outer shell, and the left gasket ring is in contact with the left metal sealing ring and the circular sample respectively.

[0023] Place the right metal sealing ring and the right gasket ring into the right outer shell in sequence, so that the right metal sealing ring is located at the angle between the annular side plate and the annular surrounding plate of the right outer shell, and the right side of the right gasket ring is in contact with the right metal sealing ring.

[0024] Install the assembled left outer shell into the annular groove of the left connecting pipe, and install the assembled right outer shell into the annular groove of the right connecting pipe. Tighten the flange on the left connecting pipe to the left end of the right connecting pipe with three screws, thereby sealing the left and right outer shells. The annular side plate of the left outer shell, the left metal sealing ring, the left gasket, the disc-shaped sample, the right gasket, and the annular side plate of the right outer shell are squeezed together from left to right, and the left and right components are squeezed and sealed. At the same time, the annular groove of the right outer shell and the right connecting pipe are squeezed and sealed, and the annular groove of the left outer shell and the left connecting pipe are squeezed and sealed.

[0025] Preferably, the left and right sides of the disc-shaped sample are coated with a palladium layer.

[0026] Palladium has excellent adsorption and dissociation capabilities for hydrogen, which can significantly improve the sensitivity of electrochemical detection signals.

[0027] For austenitic stainless steel with high hydrogen solubility and low hydrogen diffusion coefficient, existing gas-phase hydrogen permeation devices cannot detect hydrogen permeation current, and the hydrogen permeation curve is always a horizontal straight line.

[0028] This invention shortens the time required for hydrogen atoms to enter and pass through a circular sample by employing local heating. The sample module can separate the hydrogen filling vessel and the hydrogen measurement vessel by gas and liquid and reduce thermal conductivity. The palladium layer can improve detection accuracy, ultimately realizing in-situ, real-time and high-precision measurement of hydrogen permeation flux in materials with low hydrogen diffusivity.

[0029] Preferably, both the left and right metal sealing rings are made of nickel-based high-temperature alloys or 316L stainless steel.

[0030] The C-shaped metal sealing ring has high temperature resistance, high pressure resistance and corrosion resistance, and is suitable for the high temperature and high pressure hydrogen and electrolyte solution environment of this invention.

[0031] Preferably, the right outer shell and the right gasket are both made of Al2O3 material with a purity of ≥99.5%; the left outer shell and the left gasket are both made of composite ceramic material with Al2O3 as the matrix.

[0032] Al2O3 materials with a purity of ≥99.5% possess the characteristics of high temperature and high pressure resistance and corrosion resistance. Composite ceramic materials with Al2O3 as the matrix are made with the effects of high temperature and high pressure resistance and reduced thermal conductivity.

[0033] Preferably, the palladium layer is fabricated using a magnetron sputtering process, the steps of which are as follows:

[0034] Place the circular sample into the sputtering vacuum chamber of the magnetron sputtering instrument, adjust the bias voltage to 85V, the working gas pressure to 0.7Pa, and the sputtering power to 195W. Open the substrate baffle and start magnetron sputtering of the palladium layer. Use a quartz crystal microbalance to monitor the thickness of the palladium layer in real time. The deposition time is 12min-14min. Deposit 80±10nm palladium layers on the left and right sides of the circular sample.

[0035] Preferably, the counter electrode is a circular platinum sheet; the inner tube of the high-voltage reference electrode is made of porous ceramic, and the solution in the inner tube is a KCl solution.

[0036] A measurement method for a high-temperature, high-pressure hydrogen permeation measuring device includes the following steps:

[0037] Step 1: Pour 0.2 mol / L NaOH aqueous solution into the hydrogen measuring vessel until the sample module is submerged. Install the counter electrode and high-voltage reference electrode on the lid of the hydrogen measuring vessel and seal the vessel body and lid.

[0038] Step 2: A valve is installed on the air delivery pipe. The valve is initially closed. The initial value of parameter i is set to 1.

[0039] Step 2-1: Fill the gas filling vessel with nitrogen from the high-pressure nitrogen cylinder. When the reading of the second pressure gauge stabilizes at 1 MPa, slowly open the valve to allow nitrogen to flow into the hydrogen measuring vessel at a rate of 1 MPa / min. When the reading of the second pressure gauge stabilizes at 1 MPa, close the valve.

[0040] Step 2-2: If the reading of the second pressure gauge is less than 20 MPa, increase the value of i by 1 and return to step 2-1; otherwise, close the valve and proceed to step 3.

[0041] Step 3: Set the temperature to 300℃ using the temperature controller, with a heating rate of 5℃ / min. The heating resistance wire begins to heat slowly until the temperature inside the hydrogen charging vessel detected by the thermocouple reaches 300℃. Then, the temperature controller controls the thermocouple to maintain heating, keeping the temperature inside the hydrogen charging vessel between 290℃ and 300℃.

[0042] Meanwhile, 0.3 MPa of hydrogen gas is introduced into the hydrogen filling vessel through a high-pressure hydrogen cylinder for washing. After washing, hydrogen gas is continued to be introduced until the pressure detected by the first pressure gauge reaches 35 MPa, at which point the hydrogen gas introduction is stopped.

[0043] Step 4: The electrochemical workstation detects background current. When the background current drops to 10... -7 A / cm 2 At that time, the hydrogen permeation current was measured, the current density and time values ​​were recorded, and the hydrogen permeation curve was plotted.

[0044] When the current density no longer increases significantly and the hydrogen permeation curve tends to be horizontal, the temperature controller controls the thermocouple to stop heating, first venting the hydrogen in the hydrogen charging vessel, then slowly venting the nitrogen in the hydrogen measuring vessel and the gas charging vessel at a rate of 0.1 MPa / min, and finally taking out the counter electrode, the high-voltage reference electrode, and the disc sample.

[0045] Under the action of 35MPa hydrogen pressure, the left metal sealing ring expands and deforms, squeezing and sealing the angle between the annular side plate and the annular surrounding plate of the left outer shell, so that hydrogen cannot pass through the sample module and enter the hydrogen measuring vessel.

[0046] Under nitrogen pressure of 20 MPa, the right metal sealing ring expands and deforms, squeezing and sealing the angle between the annular side plate and the annular surrounding plate of the right outer shell, preventing nitrogen from passing through the sample module into the hydrogen measurement vessel and ensuring the accuracy of the measurement.

[0047] Therefore, the present invention has the following beneficial effects:

[0048] The hydrogen measurement vessel is connected to a smaller gas filling vessel. By gradually increasing and decreasing the pressure, the high-pressure reference electrode is protected, and the pressure difference between the hydrogen filling vessel and the hydrogen measurement vessel is reduced, thereby improving the stability of hydrogen permeation data measurement.

[0049] The local heating method shortens the time required for hydrogen atoms to enter and pass through the disc-shaped sample. The sample module can separate the hydrogen filling vessel and the hydrogen measurement vessel into gas and liquid phases and reduce thermal conductivity.

[0050] The palladium layer improves detection accuracy, enabling in-situ, real-time, and high-precision measurement of hydrogen permeation flux in materials with low hydrogen diffusivity, with good measurement stability. Attached Figure Description

[0051] Figure 1 This is a schematic diagram of one structure of the present invention;

[0052] Figure 2 This is a schematic diagram of a sample module of the present invention;

[0053] Figure 3 This is a hydrogen permeation curve according to an embodiment of the present invention. Detailed Implementation

[0054] The present invention will now be further described with reference to the accompanying drawings and specific embodiments.

[0055] like Figure 1The illustrated embodiment is a high-temperature, high-pressure hydrogen permeation measuring device, including a hydrogen filling vessel 1, a hydrogen measuring vessel 2 containing NaOH solution, a gas filling vessel 3, and a sample module 4. A first pressure gauge 11 and a thermocouple 12 are located at the left end of the hydrogen filling vessel. A heating resistance wire 13 is installed inside the vessel wall. The thermocouple and heating resistance wire are electrically connected to a temperature controller. The hydrogen filling vessel is connected to a high-pressure hydrogen cylinder. A counter electrode 21 and a high-pressure reference electrode 22 are provided on the hydrogen measuring vessel. A right connecting pipe 14 is provided on the hydrogen filling vessel, and a left connecting pipe 23 is provided on the hydrogen measuring vessel. The sample module... The NaOH solution level is higher than that of the left connecting pipe in the annular groove on the opposite end face of the left and right connecting pipes. The left and right connecting pipes are detachably and sealed. A second pressure gauge 31 is provided on the gas filling vessel. The gas filling vessel is connected to a high-pressure nitrogen cylinder. The gas filling vessel is connected to the upper part of the hydrogen measuring vessel through a gas guide pipe 32. The value obtained by subtracting the volume occupied by the NaOH solution from the volume in the hydrogen measuring vessel is called W. W is greater than the volume of the gas filling vessel. The sample module, the counter electrode, and the high-voltage reference electrode are all electrically connected to the electrochemical workstation. Figure 1 It is equipped with two filling ports 7, which are respectively connected to a high-pressure hydrogen cylinder and a high-pressure nitrogen cylinder.

[0056] like Figure 2 As shown, the sample module includes a left outer shell 41 and a right outer shell 47. Both the left and right outer shells include annular side plates 40 and annular surrounding plates 401 located on the inner side of the annular side plates. A left metal sealing ring 42, a left gasket ring 43, a disc-shaped sample 44, a right gasket ring 45, and a right metal sealing ring 46 are provided between the annular side plates of the left and right outer shells. The left and right outer shells, the left gasket ring, and the right gasket ring are all made of ceramic material. The cross-sections of the left and right metal sealing rings are both C-shaped with inward opening. The disc-shaped sample is electrically connected to the electrochemical workstation through a wire 48 passing through the left outer shell.

[0057] The left and right sides of the disc-shaped sample are coated with palladium.

[0058] Both the left and right metal sealing rings are made of nickel-based high-temperature alloys or 316L stainless steel.

[0059] The right outer shell and the right gasket are both made of Al2O3 material with a purity of ≥99.5%; the left outer shell and the left gasket are both made of composite ceramic material with Al2O3 as the matrix.

[0060] The palladium layer was fabricated using a magnetron sputtering process, and the magnetron sputtering steps are as follows:

[0061] The circular sample was ultrasonically cleaned in anhydrous ethanol for 7 minutes, dried and placed in a sputtering vacuum chamber. A DC power of 50W and a bias voltage of 200V were applied for argon plasma activation for 30 seconds to remove organic contaminants from the surface of the circular sample.

[0062] Place the circular sample into the sputtering vacuum chamber of the magnetron sputtering instrument, and evacuate the sputtering vacuum chamber to 5 × 10⁻⁶. - 4 Pa, high-purity argon gas is introduced into the sputtering vacuum chamber at a stable flow rate of 25 sccm, the working pressure is adjusted to 0.8 Pa, and a palladium target with a purity ≥99.95% is turned on for pre-sputtering:

[0063] Apply 150W DC power and 480V bias for 10 minutes, keeping the substrate baffle closed, to remove oxides and adsorbed impurities from the surface of the palladium target.

[0064] The bias voltage was adjusted to 85V, the working gas pressure to 0.7Pa, and the sputtering power to 195W. The substrate baffle was opened, and magnetron sputtering of the palladium layer was started. The thickness of the palladium layer was monitored in real time using a quartz crystal microbalance. The deposition time was 13 minutes, and an 80nm palladium layer was deposited on the left and right sides of the circular sample.

[0065] The counter electrode is a circular platinum sheet; the inner tube of the high-voltage reference electrode is made of porous ceramic, and the solution in the inner tube is a KCl solution.

[0066] Installation method of counter electrode: Cover the platinum wire part at the upper end of the counter electrode with an insulating shell to prevent it from conducting with the lid of the hydrogen measuring vessel. Then pass it through the hollow part of the bolt to form a whole. Use a wrench to screw the counter electrode into the lid and tighten the bolt to the lid.

[0067] Installation method of high-voltage reference electrode: Remove the filling hole nut, fill the syringe with KCl solution, inject the liquid into the electrode until a small amount of liquid flows out, tighten the nut, wrap the threads with Teflon tape, put an insulating rubber tube between the inner tube and the threads, and use a wrench to screw the electrode into the reactor lid; after installation, the lower ends of both the counter electrode and the high-voltage reference electrode should be aligned with the circular sample.

[0068] A measurement method for a high-temperature, high-pressure hydrogen permeation measuring device includes the following steps:

[0069] Step 1: Pour 0.2 mol / L NaOH aqueous solution into the hydrogen measuring vessel until the sample module is submerged. Install the counter electrode and high-voltage reference electrode on the lid of the hydrogen measuring vessel and seal the vessel body and lid.

[0070] Step 2, the air duct is equipped with such Figure 1 The valve 33 shown is initially closed, and the initial value of parameter i is set to 1.

[0071] Step 2-1: Fill the gas filling vessel with nitrogen from the high-pressure nitrogen cylinder. When the reading of the second pressure gauge stabilizes at 1 MPa, slowly open the valve to allow nitrogen to flow into the hydrogen measuring vessel at a rate of 1 MPa / min. When the reading of the second pressure gauge stabilizes at 1 MPa, close the valve.

[0072] Step 2-2: If the reading of the second pressure gauge is less than 20 MPa, increase the value of i by 1 and return to step 2-1; otherwise, close the valve and proceed to step 3.

[0073] Step 3: Set the temperature to 300℃ using the temperature controller, with a heating rate of 5℃ / min. The heating resistance wire begins to heat slowly until the temperature inside the hydrogen charging vessel detected by the thermocouple reaches 300℃. Then, the temperature controller controls the thermocouple to maintain heating, keeping the temperature inside the hydrogen charging vessel between 290℃ and 300℃.

[0074] Meanwhile, 0.3 MPa of hydrogen gas is introduced into the hydrogen filling vessel through a high-pressure hydrogen cylinder for washing. After washing, hydrogen gas is continued to be introduced until the pressure detected by the first pressure gauge reaches 35 MPa, at which point the hydrogen gas introduction is stopped.

[0075] Step 4: The electrochemical workstation detects background current. When the background current drops to 10... -7 A / cm 2 At that time, the hydrogen permeation current was measured, and the current density and time values ​​were recorded. A plot was then created as shown below. Figure 3 The hydrogen permeation curve shown;

[0076] When the current density no longer increases significantly and the hydrogen permeation curve tends to be horizontal, the temperature controller controls the thermocouple to stop heating, first venting the hydrogen in the hydrogen charging vessel, then slowly venting the nitrogen in the hydrogen measuring vessel and the gas charging vessel at a rate of 0.1 MPa / min, and finally taking out the counter electrode, the high-voltage reference electrode, and the disc sample.

[0077] like Figure 3 As shown, the present invention obtained the hydrogen permeation curve of the tested 316 stainless steel disc sample (austenitic stainless steel with a low hydrogen diffusion coefficient); while the existing gas phase hydrogen permeation device cannot detect the hydrogen permeation current of austenitic stainless steel with a low hydrogen diffusion coefficient, and the hydrogen permeation curve is always a horizontal straight line.

[0078] It can be seen that the completion time of the gas phase hydrogen permeation test for 316 stainless steel is 8×10 5 The hydrogen diffusion coefficient is relatively low, around s;

[0079] The formula for calculating hydrogen diffusion is as follows:

[0080] Effective hydrogen diffusion coefficient

[0081] Where L is the sample thickness, t 0.63 The transient current value on the hydrogen permeation curve, t 0.63 = 0.63 × steady-state current value, corresponding to the time of the point.

[0082] By studying the hydrogen permeation curves of metallic materials with low hydrogen diffusion coefficients, the hydrogen permeation behavior of austenitic stainless steel under high temperature and high pressure gas phase environments can be clarified. The horizontal axis (i.e., time) of the hydrogen permeation curve directly reflects the diffusion rate of hydrogen atoms inside the material. As the time for the hydrogen permeation curve to reach a steady state increases, a large number of hydrogen atoms are trapped by hydrogen traps (such as dislocations, grain boundaries, precipitates, and second-phase particles), resulting in a reduction in the number of free hydrogen atoms that can participate in diffusion, and the overall diffusion process is slowed down. At this time, the hydrogen diffusion coefficient is low. Based on this, the hydrogen embrittlement sensitivity of materials with low hydrogen diffusion coefficients can be further evaluated, providing reliable data support for determining the degree of hydrogen embrittlement affecting such materials in hydrogen storage and transportation environments.

[0083] The above description is only a preferred embodiment of the present invention and is not intended to limit the present invention. Any modifications, equivalent substitutions, improvements, etc., made within the spirit and principles of the present invention should be included within the protection scope of the present invention.

Claims

1. A high-temperature, high-pressure hydrogen permeation measuring device, characterized in that, The system includes a hydrogen charging vessel (1), a hydrogen measuring vessel (2) containing NaOH solution, a gas charging vessel (3), and a sample module (4). The hydrogen charging vessel is equipped with a first pressure gauge (11) and a thermocouple (12) at its left end. A heating resistance wire (13) is installed inside the vessel wall. The thermocouple and heating resistance wire are electrically connected to a temperature controller. The hydrogen charging vessel is connected to a high-pressure hydrogen cylinder. The hydrogen measuring vessel is equipped with a counter electrode (21) and a high-pressure reference electrode (22). The hydrogen charging vessel has a right connecting pipe (14), and the hydrogen measuring vessel has a left connecting pipe (23). The sample module is located at... In the annular grooves on the opposite end faces of the left and right connecting tubes, the NaOH solution level is higher than that of the left connecting tube. The left and right connecting tubes are detachably and sealed. A second pressure gauge (31) is provided on the gas filling vessel. The gas filling vessel is connected to the high-pressure nitrogen cylinder. The gas filling vessel is connected to the upper part of the hydrogen measuring vessel through the gas guide pipe (32). The value obtained by subtracting the volume occupied by the NaOH solution from the volume in the hydrogen measuring vessel is called W. W is greater than the volume of the gas filling vessel. The sample module, the counter electrode, and the high-pressure reference electrode are all electrically connected to the electrochemical workstation.

2. The high-temperature and high-pressure hydrogen permeation measuring device according to claim 1, characterized in that, The sample module includes a left outer shell (41) and a right outer shell (47). Both the left and right outer shells include annular side plates (40) and annular surrounding plates (401) located on the inner side of the annular side plates. A left metal sealing ring (42), a left gasket ring (43), a disc-shaped sample (44), a right gasket ring (45), and a right metal sealing ring (46) are provided between the annular side plates of the left and right outer shells. The left and right outer shells, the left gasket ring, and the right gasket ring are all made of ceramic material. The cross-sections of the left and right metal sealing rings are both C-shaped with inward opening. The disc-shaped sample is electrically connected to the electrochemical workstation through a wire passing through the left outer shell.

3. The high-temperature and high-pressure hydrogen permeation measuring device according to claim 2, characterized in that, The left and right sides of the disc-shaped sample are coated with palladium.

4. The high-temperature and high-pressure hydrogen permeation measuring device according to claim 2, characterized in that, Both the left and right metal sealing rings are made of nickel-based high-temperature alloys or 316L stainless steel.

5. The high-temperature and high-pressure hydrogen permeation measuring device according to claim 2, characterized in that, The right outer shell and the right gasket are both made of Al2O3 material with a purity of ≥99.5%; the left outer shell and the left gasket are both made of composite ceramic material with Al2O3 as the matrix.

6. The high-temperature and high-pressure hydrogen permeation measuring device according to claim 3, characterized in that, The palladium layer was fabricated using a magnetron sputtering process, and the magnetron sputtering steps are as follows: Place the circular sample into the sputtering vacuum chamber of the magnetron sputtering instrument, adjust the bias voltage to 85V, the working gas pressure to 0.7Pa, and the sputtering power to 195W. Open the substrate baffle and start magnetron sputtering of the palladium layer. Use a quartz crystal microbalance to monitor the thickness of the palladium layer in real time. The deposition time is 12min-14min. Deposit 80±10nm palladium layers on the left and right sides of the circular sample.

7. The high-temperature and high-pressure hydrogen permeation measuring device according to claim 1, characterized in that, The counter electrode is a circular platinum sheet; the inner tube of the high-voltage reference electrode is made of porous ceramic, and the solution in the inner tube is a KCl solution.

8. A measurement method based on the high-temperature and high-pressure hydrogen permeation measuring device according to claim 3, characterized in that, Includes the following steps: Step 1: Pour 0.2 mol / L NaOH aqueous solution into the hydrogen measuring vessel until the sample module is submerged. Install the counter electrode and high-voltage reference electrode on the lid of the hydrogen measuring vessel and seal the vessel body and lid. Step 2: A valve (33) is installed on the air duct. The valve is initially closed. The initial value of parameter i is set to 1. Step 2-1: Fill the gas filling vessel with nitrogen from the high-pressure nitrogen cylinder. When the reading of the second pressure gauge stabilizes at 1 MPa, slowly open the valve to allow nitrogen to flow into the hydrogen measuring vessel at a rate of 1 MPa / min. When the reading of the second pressure gauge stabilizes at 1 MPa, close the valve. Step 2-2: If the reading of the second pressure gauge is less than 20 MPa, increase the value of i by 1 and return to step 2-1; otherwise, close the valve and proceed to step 3. Step 3: Set the temperature to 300℃ using the temperature controller, with a heating rate of 5℃ / min. The heating resistance wire begins to heat slowly until the temperature inside the hydrogen charging vessel detected by the thermocouple reaches 300℃. Then, the temperature controller controls the thermocouple to maintain heating, keeping the temperature inside the hydrogen charging vessel between 290℃ and 300℃. Meanwhile, 0.3 MPa of hydrogen gas is introduced into the hydrogen filling vessel through a high-pressure hydrogen cylinder for washing. After washing, hydrogen gas is continued to be introduced until the pressure detected by the first pressure gauge reaches 35 MPa, at which point the hydrogen gas introduction is stopped. Step 4: The electrochemical workstation detects background current. When the background current drops to 10... -7 A / cm 2 At that time, the hydrogen permeation current was measured, the current density and time values ​​were recorded, and the hydrogen permeation curve was plotted. When the current density no longer increases significantly and the hydrogen permeation curve tends to be horizontal, the temperature controller controls the thermocouple to stop heating, first venting the hydrogen in the hydrogen charging vessel, then slowly venting the nitrogen in the hydrogen measuring vessel and the gas charging vessel at a rate of 0.1 MPa / min, and finally taking out the counter electrode, the high-voltage reference electrode, and the disc sample.

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