Method for evaluating hydrogen embrittlement performance of hydrogen conveying pipeline

Abstract

The invention discloses a hydrogen brittleness performance evaluation method for a hydrogen transport pipeline, which comprises the following steps: obtaining the average hydrogen concentration in a sample through a high-pressure hydrogen permeation test of a wafer sample, and obtaining the hydrogen concentration and hydrogen diffusion coefficient of the surface of the sample under a specific electrochemical hydrogen charging condition through an electrochemical hydrogen charging test of the wafer sample; a finite element analysis model of a target sample is established to simulate the change relation of the total amount of hydrogen atoms in the target sample along with time under the electrochemical hydrogen charging condition, and the electrochemical hydrogen charging time equivalent to the high-pressure gaseous hydrogen charging is obtained by comparing the high-pressure gaseous hydrogen charging with the electrochemical hydrogen charging. The target sample is charged with hydrogen through an electrochemical hydrogen charging method, and finally the hydrogen embrittlement performance of the target sample is obtained through a hydrogen embrittlement performance test. According to the method, simple finite element simulation and electrochemical hydrogen charging are combined, high-pressure gaseous hydrogen charging which is complex, low in efficiency and high in danger is replaced, and the detection time of the hydrogen embrittlement performance test of the hydrogen charging pipe is shortened.

Description

Technical Field

[0001] This invention relates to the field of determining the hydrogen embrittlement sensitivity of metallic materials, and in particular to a method for evaluating the hydrogen embrittlement performance of hydrogen transport pipelines using electrochemical hydrogen charging equivalent to high-pressure gaseous hydrogen charging. Background Technology

[0002] In recent years, with the development of the hydrogen energy industry, the construction mileage of hydrogen pipelines has gradually increased. To improve transportation efficiency and economy, there is a trend towards high-strength steel in the pipe materials used for hydrogen pipelines. However, high-strength pipeline steel is significantly more sensitive to hydrogen than medium- and low-strength pipeline steel. Once a pipeline breaks due to hydrogen embrittlement, the consequences could be catastrophic. Therefore, whether it is a newly built pipeline or an existing pipeline, it is necessary to carefully assess the impact of different high-pressure hydrogen environments (such as hydrogen pressure, hydrogen content, impurity gas content, temperature, etc.) on the performance of the pipe material, that is, to evaluate the hydrogen embrittlement performance of the pipe material under different high-pressure hydrogen environments. Currently, to simulate the high-pressure hydrogen environment faced by actual hydrogen pipelines, high-pressure gaseous hydrogen charging test platforms are established in laboratories. Target samples (such as tensile samples, three-point bend samples, compact tensile samples, CTOD samples, etc.) are charged with hydrogen using a high-pressure hydrogen charging reactor, and then mechanical tests are performed on the hydrogen-charged samples to evaluate their hydrogen embrittlement performance under different hydrogen environments. This method of high-pressure gaseous hydrogen charging in the laboratory not only poses certain dangers due to the frequent use of high-pressure hydrogen reactors, but also wastes hydrogen resources. Summary of the Invention

[0003] To address the aforementioned technical problems, this invention provides a method for evaluating the hydrogen embrittlement performance of hydrogen transportation pipelines. This invention employs electrochemical hydrogen charging instead of high-pressure gaseous hydrogen charging, achieving the same charging effect, thereby avoiding the dangers and excessive waste of hydrogen associated with high-pressure gaseous hydrogen charging.

[0004] The present invention is achieved by the following technical solution.

[0005] A method for evaluating the hydrogen embrittlement performance of hydrogen transportation pipelines includes the following steps:

[0006] S1. The average hydrogen concentration C0 / 2 inside the sample under a specific gaseous hydrogen filling condition is obtained by high-pressure hydrogen permeation test of the disc sample;

[0007] S2. An electrochemical hydrogen charging test was conducted on the disc sample by controlling the applied hydrogen charging cathode potential E. ca The hydrogen concentration C on the sample surface was obtained under specific electrochemical hydrogen charging conditions. 0,e and hydrogen diffusion coefficient D eff,e ;

[0008] S3. The relationship between the total amount of hydrogen atoms inside the target sample and time under electrochemical hydrogen charging conditions is simulated by establishing a finite element analysis model of the target sample.

[0009] S4. By multiplying the average hydrogen concentration C0 / 2 of the sample measured in step S1 by the volume V of the target sample, the total hydrogen content C0 / 2·V of the target sample under steady-state hydrogen charging conditions is obtained. The time corresponding to this total hydrogen content is the electrochemical hydrogen charging time t, which is equivalent to high-pressure gaseous hydrogen charging. eff ;

[0010] S5. Perform an electrochemical hydrogen charging test on the target sample; during the electrochemical hydrogen charging test, set the cathode potential to the potential E in step S2. ca The hydrogen charging time is the time t obtained in step S4. eff ;

[0011] S6. Obtain the hydrogen embrittlement properties of the target sample through hydrogen embrittlement performance testing.

[0012] By employing the above technical solution, this invention addresses situations where high-pressure gaseous hydrogen charging is inconvenient, using electrochemical hydrogen charging as an alternative to high-pressure gaseous hydrogen charging to evaluate the hydrogen embrittlement performance of samples. Since the electrochemical hydrogen charging rate is greater than that of high-pressure gaseous hydrogen charging, this method significantly shortens the charging time and avoids the experimental risks associated with high-pressure gaseous hydrogen charging, solving the problem of difficult high-pressure gaseous hydrogen charging for irregularly shaped samples. Overall, this invention, through a combination of simple finite element simulation and electrochemical hydrogen charging, replaces the complex, inefficient, and highly dangerous high-pressure gaseous hydrogen charging method, shortening the testing time for hydrogen embrittlement performance tests on hydrogen-charged pipes.

[0013] Furthermore, in step S1, the specific method for the high-pressure hydrogen permeation test of the disc sample is as follows: the hydrogen-filled side of the disc sample faces a high-pressure gaseous hydrogen environment, and the other oxidation side faces a sodium hydroxide solution. The change curve of the hydrogen permeation current density of the sample oxidation over time is measured by a three-electrode system and an electrochemical workstation. Then, the curve is analyzed by the time lag method, Fick's diffusion law and Faraday's law to obtain the average hydrogen concentration C0 / 2 inside the sample.

[0014] Furthermore, the high-pressure hydrogen permeation test device for the disc sample includes a high-pressure gas reactor equipped with a pressure gauge. An anode cell is located on one side of the high-pressure gas reactor. A disc sample is placed between the high-pressure gas reactor and the anode cell. The anode cell is equipped with an auxiliary electrode and a reference electrode. The auxiliary electrode and the reference electrode are connected to an electrochemical workstation. The disc sample is also connected to the electrochemical workstation via a wire.

[0015] Furthermore, in step S2, the electrochemical hydrogen charging test of the circular sample is performed with hydrogen charging at a constant potential, and the hydrogen permeation curve is analyzed by the time lag method, Fick's diffusion law, and Faraday's law to obtain the hydrogen concentration C on the sample surface. 0,e Hydrogen diffusion coefficient D eff,e .

[0016] Furthermore, the disc sample electrochemical hydrogen charging test device includes an anode cell and a hydrogen charging cell, with a disc sample placed between the anode cell and the hydrogen charging cell. Both the anode cell and the hydrogen charging cell are equipped with auxiliary electrodes and reference electrodes. The auxiliary electrodes and reference electrodes of the anode cell are connected to an electrochemical workstation, and the auxiliary electrodes and reference electrodes of the hydrogen charging cell are connected to a potentiostat. The disc sample is connected to the electrochemical workstation and the potentiostat respectively via wires.

[0017] In step S3, the target sample is simulated using a finite element analysis model, and the hydrogen concentration C on the sample surface is calculated based on the electrochemical hydrogen charging test of the disc sample. 0,e and hydrogen diffusion coefficient D eff,e To simulate the input conditions, the hydrogen concentration inside the target sample was integrated to obtain the curve of the total hydrogen content inside the sample changing over time.

[0018] This application has the following beneficial effects.

[0019] 1. This invention combines high-pressure hydrogen permeation, electrochemical hydrogen charging, and hydrogen charging process of target sample with finite element simulation. By measuring the electrochemical hydrogen charging potential and time of target sample, it is possible to use electrochemical hydrogen charging to replace high-pressure gaseous hydrogen charging, thereby avoiding the dangers and waste of hydrogen resources caused by frequent high-pressure gaseous hydrogen charging.

[0020] 2. This invention uses the parameters measured by the electrochemical hydrogen charging test as the input conditions for the finite element hydrogen diffusion simulation, so that the finite element hydrogen diffusion simulation can more accurately reflect the dynamic process of electrochemical hydrogen charging of the target sample.

[0021] 3. In this invention, the high-pressure hydrogen permeation test and electrochemical hydrogen charging test of the circular sample only need to be performed once, and the hydrogen charging time of target samples of different shapes can be obtained through finite element simulation technology, which greatly shortens the evaluation cycle. Attached Figure Description

[0022] Figure 1 This is a technical roadmap of the present invention;

[0023] Figure 2 This is a schematic diagram of the high-pressure hydrogen permeation test device for circular sample of the present invention;

[0024] Figure 3 This is a set of curves showing the change of high-pressure hydrogen permeation current over time, as measured by the present invention.

[0025] Figure 4 This is a schematic diagram of the structure of the electrochemical hydrogen permeation test device for disc samples of the present invention;

[0026] Figure 5 This is a set of curves showing the change of electrochemical hydrogen permeation current density over time, obtained by this invention.

[0027] Figure 6 This is a schematic diagram of the finite element modeling process in an embodiment of the present invention (wherein, 6-1 is the target sample drawing; 6-2 is the three-dimensional geometric model of the target sample; 6-3 is the finite element model of the target sample; and 6-4 is the hydrogen permeation simulation result of the target sample).

[0028] Figure 7 This is a finite element simulation result curve and a schematic diagram for determining the equivalent hydrogen charging time in an embodiment of the present invention.

[0029] The components include: 1. High-pressure gas reactor; 2. Anode cell; 3. Circular sample; 4. Auxiliary electrode; 5. Reference electrode; 6. Pressure gauge; 7. Electrochemical workstation; 8. Hydrogen charging cell; 9. Potentiostat; and 10. Target sample. Detailed Implementation

[0030] The following will describe in detail the embodiments of the present invention in the Weinan Depression of the Beibu Gulf Basin with reference to the accompanying drawings. Unless otherwise specified, the materials used in the preparation process in the following embodiments have not undergone further processing and have been commercially available.

[0031] Example

[0032] like Figure 1 As shown, a method for evaluating the hydrogen embrittlement performance of hydrogen pipeline materials using electrochemical hydrogen charging equivalent to high-pressure gaseous hydrogen charging includes the following six steps:

[0033] Step 1: High-pressure hydrogen permeation test of circular sample: A high-pressure hydrogen permeation test is performed on the circular sample, where the gaseous environment is the target environment. By analyzing the measured hydrogen permeation curve, the average hydrogen concentration C0 / 2 inside the circular sample under the target environment condition is obtained.

[0034] Commonly used test apparatus in this step include: Figure 2 As shown, the system includes a high-pressure gas reactor 1, equipped with a pressure gauge 6. An anode cell 2 is located on one side of the high-pressure gas reactor 1. A circular sample 3 is placed between the high-pressure gas reactor 1 and the anode cell 2. The anode cell 2 is equipped with an auxiliary electrode 4 and a reference electrode 5, which are connected to an electrochemical workstation 7. The circular sample 3 is also connected to the electrochemical workstation 7 via wires. The high-pressure gas reactor 1 is filled with hydrogen gas or a mixture of hydrogen and other gases, and the pressure is measured by the pressure gauge 6. A 0.1 mol / L NaOH solution is introduced into the anode cell 2. Hydrogen atoms permeate into the circular sample 3 under high pressure and are released on one side of the anode cell 2. The hydrogen atoms are oxidized by the anolytical potential provided by the electrochemical workstation 7, thus forming a hydrogen permeation current. The curve of the hydrogen permeation current over time is recorded by the electrochemical workstation. Figure 3As shown. The hydrogen concentration C0 on the hydrogen-charged side of the sample can be determined using the time lag method, Fick's diffusion law, and Faraday's law; the value is 8.26 × 10⁻⁶. -3 mol / m 3 Furthermore, since the hydrogen diffusion in the disc sample 3 is one-dimensional, when the diffusion is stable, the hydrogen concentration inside the sample is linearly distributed, and all the hydrogen atoms on the anode side of the sample are oxidized to hydrogen ions, that is, the hydrogen concentration is 0. Therefore, it can be known that the average hydrogen concentration inside the sample is CO / 2.

[0035] Step 2: Electrochemical hydrogen permeation test of disc samples: An electrochemical hydrogen charging test is performed on the disc samples by controlling the applied hydrogen charging cathode potential E. ca (e.g. -1200mV) SCE The hydrogen permeation curve of the sample was obtained, and the hydrogen concentration C on the hydrogen-charged side of the sample was obtained by processing the curve. 0,e and hydrogen diffusion coefficient D eff,e .

[0036] Commonly used test apparatus in this step include: Figure 4 As shown, the system includes an anode cell 2 and a hydrogen-filling cell 8, with a circular sample 3 positioned between them. Both the anode cell 2 and the hydrogen-filling cell 8 are equipped with auxiliary electrodes 4 and reference electrodes 5. The auxiliary electrodes 4 and reference electrodes 5 of the anode cell 2 are connected to an electrochemical workstation 7, and the auxiliary electrodes 4 and reference electrodes 5 of the hydrogen-filling cell 8 are connected to a potentiostat 9. The circular sample 3 is connected to both the electrochemical workstation 7 and the potentiostat 9 via wires. The hydrogen-filling side is the hydrogen-filling cell 8, which contains a certain solution. The cathode potential provided by the potentiostat 9 causes a cathodic hydrogen evolution reaction to occur on the hydrogen-filling side of the circular sample 3, allowing hydrogen atoms to penetrate and diffuse to the anode cell 2. The anodic potential provided by the electrochemical workstation 7 causes the hydrogen atoms to oxidize, thereby measuring the hydrogen permeation current density curve. Figure 5 As shown. The surface hydrogen concentration C of the steel can be determined using the time lag method, Fick's diffusion law, and Faraday's law. 0,e 0.55 mol / m 3 steel diffusion coefficient D eff,e 1.1×10 -10 m 2 / s.

[0037] Step 3: Perform finite element hydrogen diffusion simulation analysis on the target sample, as follows: Figure 6 As shown.

[0038] This embodiment uses a notched cylindrical tensile specimen as an example to illustrate the specific implementation steps. First, a geometric model of the target specimen 10 is established based on the drawing. Then, the established geometric model is meshed to discretize its computational domain. The model is set according to the electrochemical hydrogen permeation results of the circular specimen 3, and the hydrogen diffusion concentration on the model surface is taken as C in step 2. 0,e The diffusion coefficient is taken as D in step 2. eff,e The solution step size was set to 1 s, and the hydrogen diffusion concentration distribution of the sample at different times was calculated. Finally, the total amount of hydrogen inside the sample at different times was obtained by volume integral of the hydrogen atom concentration in all grid cells, and the curve of the total amount of hydrogen changing with time was plotted, as shown in the figure. Figure 7 As shown;

[0039] Step 4: Calculate the equivalent time for electrochemical hydrogen charging: By multiplying the average hydrogen concentration C0 / 2 of the sample measured in Step 1 by the volume V of the target sample, the total hydrogen content C0 / 2·V of the target sample under steady-state hydrogen charging conditions can be obtained. The time corresponding to this total hydrogen content is the equivalent time t. eff ,like Figure 7 As shown.

[0040] The equivalent electrochemical hydrogen charging time is obtained by comparing the results of high-pressure hydrogen permeation test of the disc sample, the results of electrochemical hydrogen permeation of the disc sample, and the results of finite-part simulation of the target sample. It represents that if the target sample is electrochemically charged with hydrogen according to this time, the total amount of hydrogen inside the target sample will be the same as that charged with high-pressure gas hydrogen.

[0041] Step 5: Electrochemical hydrogen charging test of the target sample: During the electrochemical hydrogen charging test, the cathode potential is set to the potential E in step 2. ca The hydrogen charging time is the time t obtained in step 4. eff ;

[0042] Step 6: Hydrogen embrittlement test of the target sample: The hydrogen embrittlement performance of the target sample after electrochemical hydrogen charging in Step 5 is tested (such as tensile test, CTOD test or three-point bend test, etc.), and the hydrogen embrittlement sensitivity of the sample is 23%.

[0043] This invention creatively combines five processes—high-pressure gaseous hydrogen permeation, electrochemical hydrogen permeation, finite element simulation, electrochemical hydrogen charging, and hydrogen embrittlement performance testing—into a single system. It achieves an equivalent replacement of high-pressure gaseous hydrogen charging with electrochemical hydrogen charging, which is simple, fast, and avoids the dangers and waste of hydrogen resources caused by frequent high-pressure hydrogen charging tests.

[0044] The embodiments described herein are preferred embodiments of the present invention and are not intended to limit the scope of protection of the present invention. Therefore, all equivalent changes made in accordance with the structure, shape, and principle of the present invention should be covered within the scope of protection of the present invention.

Claims

1. A method for evaluating the hydrogen embrittlement performance of hydrogen transportation pipelines, characterized in that: Includes the following steps: S1. The average hydrogen concentration C0 / 2 inside the sample under a specific gaseous hydrogen filling condition is obtained by high-pressure hydrogen permeation test of the disc sample; S2. An electrochemical hydrogen charging test was conducted on the disc sample by controlling the applied hydrogen charging cathode potential E. ca The hydrogen concentration C on the sample surface was obtained under specific electrochemical hydrogen charging conditions. 0,e and hydrogen diffusion coefficient D eff,e ; S3. The relationship between the total amount of hydrogen atoms inside the target sample and time under electrochemical hydrogen charging conditions is simulated by establishing a finite element analysis model of the target sample. S4. By multiplying the average hydrogen concentration C0 / 2 of the sample measured in step S1 by the volume V of the target sample, the total hydrogen content C0 / 2·V of the target sample under steady-state hydrogen charging conditions is obtained. The time corresponding to this total hydrogen content is the electrochemical hydrogen charging time t, which is equivalent to high-pressure gaseous hydrogen charging. eff ; S5. Perform an electrochemical hydrogen charging test on the target sample; during the electrochemical hydrogen charging test, set the cathode potential to the potential E in step S2. ca The hydrogen charging time is the time t obtained in step S4. eff ; S6. Obtain the hydrogen embrittlement properties of the target sample through hydrogen embrittlement performance testing.

2. The method for evaluating the hydrogen embrittlement performance of a hydrogen transportation pipeline according to claim 1, characterized in that: In step S1, the specific method for the high-pressure hydrogen permeation test of the disc sample is as follows: the hydrogen-filled side of the disc sample faces a high-pressure gaseous hydrogen environment, and the other oxidation side faces a sodium hydroxide solution. The change curve of the hydrogen permeation current density of the sample oxidation is measured with time through a three-electrode system and an electrochemical workstation. Then, the curve is analyzed by the time lag method, Fick's diffusion law and Faraday's law to obtain the average hydrogen concentration C0 / 2 inside the sample.

3. The method for evaluating the hydrogen embrittlement performance of a hydrogen transportation pipeline according to claim 2, characterized in that: The high-pressure hydrogen permeation test device for the disc sample includes a high-pressure gas reactor (1), which is equipped with a pressure gauge (6). An anode cell (2) is provided on one side of the high-pressure gas reactor (1). A disc sample (3) is placed between the high-pressure gas reactor (1) and the anode cell (2). The anode cell (2) is equipped with an auxiliary electrode (4) and a reference electrode (5). The auxiliary electrode (4) and the reference electrode (5) are connected to an electrochemical workstation (7). The disc sample (3) is also connected to the electrochemical workstation (7) through a wire.

4. The method for evaluating the hydrogen embrittlement performance of a hydrogen transportation pipeline according to claim 1, characterized in that: In step S2, the electrochemical hydrogen charging test of the circular sample was conducted at a constant potential, and the hydrogen permeation curve was analyzed using the time lag method, Fick's diffusion law, and Faraday's law to obtain the hydrogen concentration C on the sample surface. 0,e Hydrogen diffusion coefficient D eff,e .

5. The method for evaluating the hydrogen embrittlement performance of a hydrogen transportation pipeline according to claim 4, characterized in that: The disc sample electrochemical hydrogen charging test device includes an anode cell (2) and a hydrogen charging cell (8). A disc sample (3) is placed between the anode cell (2) and the hydrogen charging cell (8). Both the anode cell (2) and the hydrogen charging cell (8) are equipped with an auxiliary electrode (4) and a reference electrode (5). The auxiliary electrode (4) and the reference electrode (5) of the anode cell (2) are connected to the electrochemical workstation (7). The auxiliary electrode (4) and the reference electrode (5) of the hydrogen charging cell (8) are connected to the potentiostat (9). The disc sample (3) is connected to the electrochemical workstation (7) and the potentiostat (9) respectively through wires.

6. The method for evaluating the hydrogen embrittlement performance of a hydrogen transportation pipeline according to claim 1, characterized in that: In step S3, the target sample is simulated using a finite element analysis model, and the hydrogen concentration C on the sample surface is calculated based on the electrochemical hydrogen charging test of the disc sample. 0,e and hydrogen diffusion coefficient D eff,e To simulate the input conditions, the hydrogen concentration inside the target sample was integrated to obtain the curve of the total hydrogen content inside the sample changing over time.

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