Test device and test method for simulating corrosion of supercritical carbon dioxide transportation pipeline

Abstract

The present invention discloses a test device and a test method for simulating the corrosion of a supercritical carbon dioxide transportation pipeline, comprising: an argon gas cylinder, a carbon dioxide gas cylinder, an impurity gas cylinder, a gas mixer, a container and a reaction kettle; the argon gas cylinder is connected to an inlet pipe at the lower part of the reaction kettle; both the carbon dioxide gas cylinder and the impurity gas cylinder are connected to the gas mixer, the gas mixer is connected to the container filled with deionized water through a pipeline, and a steam evaporator is arranged on the container; an outlet pipe of the container is connected to an inlet pipe of the reaction kettle; a specimen rack for hanging a test is arranged inside the reaction kettle, and a heating unit is arranged outside the reaction kettle; an outlet pipe is arranged at the upper part of the reaction kettle. The present invention can truly simulate the service conditions of a supercritical carbon dioxide transportation pipeline, and can study the influence of impurity gas and water vapor content on the corrosion of supercritical carbon dioxide, so as to improve the accuracy and effectiveness of the evaluation of metal corrosion tests.

Description

Technical Field

[0001] The invention belongs to the technical field of metal corrosion experiments, and in particular relates to a test device and a test method for simulating corrosion of a supercritical carbon dioxide transmission pipeline. Background Art

[0002] In recent years, energy supply and climate change have become key issues restricting global economic development. In particular, excessive emissions of greenhouse gases have caused global warming, seriously affecting economic construction and people's lives. CCUS (abbreviation for Carbon capture, utilization and storage) is a mainstream technology for dealing with carbon emissions and greenhouse effects internationally, including carbon capture, utilization and storage. Specifically, CCUS separates carbon dioxide from power plants, coal-based industries or other emission sources, enriches, compresses and transports it to a specific location, and injects it into the reservoir for storage to achieve long-term separation of the captured carbon dioxide from the atmosphere. According to estimates by the International Energy Agency, CCUS technology is expected to reduce carbon emissions by more than 20% worldwide.

[0003] In my country, high-emission industries such as coal chemical industry, steel, and cement have heavy greenhouse gas emission reduction tasks, so the application prospects of CCUS technology are very broad. In addition, in the oil and gas industry, the technical practice of carbon dioxide flooding to enhance oil recovery has also been promoted and applied. Therefore, CCUS technology is of great significance to my country's medium- and long-term response to climate change and promotion of low-carbon development.

[0004] Nevertheless, the corrosion of metal pipes by CO2 cannot be ignored. In particular, during the transportation and injection of supercritical CO2, corrosion problems of metal pipes emerge one after another. In addition, the impurity content of CO2 varies depending on its source, and the impact of impurities on corrosion is also relatively complex. This is the main problem affecting the development of CCUS technology.

[0005] The so-called supercritical carbon dioxide refers to the stable single phase state of pure carbon dioxide when its pressure and temperature simultaneously exceed its critical value (7.38MPa, 31.4℃). It has some unique properties, such as density close to that of liquid, low viscosity, and large diffusion coefficient. These unique properties make its corrosion mechanism on metal pipes different from the common carbon dioxide corrosion. Therefore, the study of supercritical carbon dioxide corrosion has attracted the attention of many scholars. Limited by the structure and function limitations of traditional reactors, there are currently two common so-called "supercritical carbon dioxide" environments: one is to immerse the sample in a solution, and then introduce carbon dioxide to make it exceed the critical point temperature and pressure; the other is to suspend the sample above the solution, and then introduce carbon dioxide to make it exceed the critical point temperature and pressure. The first environment is far from the service environment of the supercritical carbon dioxide transmission pipeline. Since the sample is immersed in the solution, the corrosion is relatively serious. The second environment is relatively close to the service environment of the supercritical carbon dioxide transmission pipeline, but there are two problems: one is the problem of carbon dioxide consumption in a sealed environment, and the other is the problem that the water content in carbon dioxide cannot be effectively and clearly controlled. Therefore, the test rules obtained through these two simulation environments cannot effectively represent the service conditions of supercritical carbon dioxide transmission pipelines, and the large deviation may even lead to invalid test results. Summary of the invention

[0006] The technical problem to be solved by the present invention is to provide a test device and a test method for simulating the corrosion of a supercritical carbon dioxide transmission pipeline in view of the deficiencies in the above-mentioned prior art, which can truly simulate the service environment of the supercritical carbon dioxide transmission pipeline and can achieve the quantitative introduction of impurity gas and water vapor content, thereby improving the pertinence, accuracy and effectiveness of the simulation test.

[0007] The present invention adopts the following technical solutions:

[0008] A test device for simulating corrosion of a supercritical carbon dioxide delivery pipeline, comprising: an argon gas cylinder, a carbon dioxide gas cylinder, an impurity gas cylinder, a gas mixer, a container and a reactor;

[0009] The argon gas bottle is connected to the air inlet pipe at the bottom of the reactor;

[0010] The carbon dioxide gas cylinder and the impurity gas gas cylinder are both connected to a gas mixer, which is connected to a container containing deionized water through a pipeline, and a steam evaporator is provided on the container; the gas outlet pipe of the container is connected to the gas inlet pipe of the reactor;

[0011] The reactor is provided with a sample rack for suspension test inside, and a heating unit outside; and an air outlet pipe is provided on the upper part of the reactor.

[0012] Preferably, the argon gas cylinder is connected to the reaction kettle via a first pressure reducing valve and a three-way valve.

[0013] Preferably, the carbon dioxide cylinder and the impurity gas cylinder are connected to the gas mixer via a second pressure reducing valve and a third pressure reducing valve, respectively.

[0014] Preferably, the steam evaporator comprises a first heater, a first thermocouple and a first temperature controller, the first heater is arranged at the bottom of the container, the first thermocouple is arranged in the container, and the first temperature controller is electrically connected to the first thermocouple.

[0015] Preferably, a booster pump is provided on the air outlet pipe of the container.

[0016] Preferably, the air outlet pipe of the container and the air inlet pipe of the reactor are connected through a three-way valve, and the air inlet pipe of the reactor is an insulation pipe.

[0017] Preferably, the heating unit includes a preheating tube bundle, a second heater, a second thermocouple and a second temperature controller. The preheating tube bundle is embedded in the inner cavity of the reactor, the sample rack is arranged in the preheating tube bundle, the second heater is embedded in the outer wall of the reactor, the second thermocouple is arranged in the preheating tube bundle, and the second thermocouple is electrically connected to the second temperature controller.

[0018] Preferably, a control valve and a pressure gauge are provided on the gas outlet pipe of the reactor.

[0019] Preferably, the gas outlet pipe of the reactor is connected to the first-stage absorption solution tank and the second-stage absorption solution tank in sequence, and the outlet of the second-stage absorption solution tank is emptied.

[0020] A test method for a test device simulating corrosion of a supercritical carbon dioxide transmission pipeline comprises the following steps:

[0021] S1. Add deionized water into the container, seal it, and heat the deionized water to the target temperature using a steam evaporator;

[0022] S2, connecting the argon gas bottle to the reactor, and using argon gas to discharge the air in the reactor;

[0023] S3, regulating the heating unit so that the internal temperature of the reactor reaches the target temperature;

[0024] S4, connecting the steam evaporator to the reactor, adjusting the flow rates of various gases to control the ratio of the mixed gas, and regulating the water vapor content in the mixed gas;

[0025] S5, passing the mixed gas carrying water vapor into the reactor;

[0026] S6. Conducting a supercritical carbon dioxide corrosion test process;

[0027] S7. After the test is completed, repeat step S2 to exhaust the carbon dioxide gas in the reactor, turn off the heating unit, and after the temperature in the reactor drops to room temperature, take out the sample for relevant analysis.

[0028] Compared with the prior art, the present invention has at least the following beneficial effects:

[0029] The present invention is a test device for simulating the corrosion of a supercritical carbon dioxide delivery pipeline. The argon cylinder is connected to a reactor through a three-way valve to discharge the air in the reactor before the test. The carbon dioxide cylinder and the impurity gas cylinder are mixed into a mixed gas through a gas mixer, and a certain amount of water vapor is carried through a steam evaporator, and then connected to the reactor through a three-way valve, so as to achieve a supercritical state of a mixed carbon dioxide gas containing a certain amount of water vapor. The sample is vertically suspended on a sample rack, and the flow direction of the supercritical carbon dioxide is kept parallel to the main observation surface of the sample, so as to completely simulate the service condition of the supercritical carbon dioxide delivery pipeline. After the mixed gas passes through the reactor outlet, it is chemically treated with a two-stage absorption solution to prevent harm to personnel and air. The present invention has a simple structure, is easy to assemble, is easy to operate, and is low in cost. It can truly simulate the service condition of a supercritical carbon dioxide delivery pipeline, and can study the influence of parameters such as impurity gas, water vapor content, and flow rate on the corrosion of supercritical carbon dioxide, effectively solve the current false test law introduced due to the deviation of test conditions, and improve the accuracy and effectiveness of metal corrosion test evaluation.

[0030] Furthermore, carbon dioxide can be mixed with other gases through a gas mixer, and the content of other gases can be quantitatively controlled.

[0031] Furthermore, the water content in the supercritical carbon dioxide can be regulated by controlling the temperature of the deionized water by the first temperature controller, and the water vapor content thereof can be accurately calculated.

[0032] Furthermore, the flow direction of the supercritical carbon dioxide remains parallel to the main observation surface of the sample, which can truly simulate the service environment of the supercritical carbon dioxide transmission pipeline.

[0033] The present invention also provides a test method for corrosion test, which is divided into three steps: the first step is to use argon to drive out the air in the reactor; the second step is to pass carbon dioxide or a mixed gas formed by carbon dioxide and other gases through a gas mixer into a steam evaporator, control the water content in the gas by temperature, and pressurize the gas carrying a certain amount of water vapor to the reactor heated to the target temperature through a gas booster pump, and keep the flow direction parallel to the main observation surface of the sample, and adjust the control valve at the outlet of the reactor so that the pressure in the reactor reaches the target value, and is displayed by a fourth pressure gauge, and the outflowing gas is chemically treated by a two-stage absorption solution tank; the third step is to repeat the first step after the test is completed, use argon to drive out the reaction gas in the reactor, turn off the heating device, and take out the sample for other related analysis after the temperature in the reactor is reduced to room temperature. The test method of the present invention effectively simulates the supercritical carbon dioxide corrosion environment by controlling the proportion of the mixed gas and the water vapor content, and provides a real simulation effect for the corrosion test of the transportation pipeline. The test results are more real and effective, and the pertinence, accuracy and effectiveness of the simulation test are improved.

[0034] The technical solution of the present invention is further described in detail below through the accompanying drawings and embodiments. BRIEF DESCRIPTION OF THE DRAWINGS

[0035] Figure 1 A schematic diagram of a test device for simulating corrosion of a supercritical carbon dioxide transmission pipeline provided by the present invention.

[0036] Wherein: 1. Argon gas cylinder; 2. Carbon dioxide gas cylinder; 3. Impurity gas cylinder; 4. First pressure gauge; 5. Second pressure gauge; 6. Third pressure gauge; 7. First pressure reducing valve; 8. Second pressure reducing valve; 9. Third pressure reducing valve; 10. Gas mixer; 11. Three-way valve; 12. Gas booster pump; 13. Container containing deionized water; 14. First heater; 15. First thermocouple; 16. First temperature controller; 17. Insulation tube; 18. Sample rack; 19. Reactor; 20. Sample; 21. Preheating tube; 22. Second heater; 23. Second thermocouple; 24. Second temperature controller; 25. Fourth pressure gauge; 26. Control valve; 27. First-stage absorption solution tank; 28. Second-stage absorption solution tank. DETAILED DESCRIPTION

[0037] In the description of the present invention, it should be understood that the orientation or positional relationship indicated by the terms "bottom", "inside", "outside", etc. is based on the orientation or positional relationship shown in the accompanying drawings, and is only for the convenience of describing the present invention and simplifying the description, rather than indicating or implying that the device or element referred to must have a specific orientation, be constructed and operated in a specific orientation, and therefore cannot be understood as a limitation on the present invention. In addition, the terms "first" and "second" are only used for descriptive purposes, and cannot be understood as indicating or implying relative importance or implicitly indicating the number of technical features indicated. Therefore, the features defined as "first" and "second" may explicitly or implicitly include one or more of the features. In the description of the present invention, unless otherwise specified, "multiple" means two or more.

[0038] The invention provides a test device for simulating corrosion of a supercritical carbon dioxide transmission pipeline.

[0039] See also Figure 1 The test device of the present invention includes an argon gas cylinder 1, a carbon dioxide gas cylinder 2, an impurity gas gas cylinder 3, a first pressure gauge 4, a second pressure gauge 5, a third pressure gauge 6, a first pressure reducing valve 7, a second pressure reducing valve 8, a third pressure reducing valve 9, a gas mixer 10, a three-way valve 11, a gas booster pump 12, a container 13, a first heater 14, a first thermocouple 15, a first temperature controller 16, an insulation tube 17, a sample rack 18, a reactor 19, a sample 20, a preheating tube 21, a second heater 22, a second thermocouple 23, a second temperature controller 24, a fourth pressure gauge 25, a control valve 26, a first-stage absorption solution tank 27, and a second-stage absorption solution tank 28. The specific requirements and functions of each component are as follows:

[0040] The argon cylinder 1 enters the reactor 19 through the first pressure reducing valve 7 and the three-way valve 11 in sequence, with the purpose of removing the air in the reactor 19. The argon flow rate is 100 mL / min, and the introduction time is 100 min. The air in the reactor is driven out and discharged after passing through the control valve 26. The purpose is to remove the air in the reactor 19 and eliminate the influence of air media such as oxygen on the corrosion of supercritical carbon dioxide.

[0041] The carbon dioxide gas cylinder 2 and the impurity gas cylinder 3 (select SO 2 ) is mixed by a gas mixer to control SO 2The content is 5%. The gases in the carbon dioxide cylinder 2 and the impurity gas cylinder 3 enter the gas mixer 10 through the second pressure reducing valve 8 and the third pressure reducing valve 9 to prepare the target mixed gas, and pass through the container 13 filled with deionized water heated to a certain temperature by the first heater 14 to become a carbon dioxide mixed gas containing a certain water vapor content, and then pressurized to a certain pressure by the gas booster pump 12, and enter the reactor 19 through the three-way valve 11 and the insulation pipe 17. The gases in the carbon dioxide cylinder 2 and the impurity gas cylinder 3 are mixed by the gas mixer, which can be used to study the influence of impurity gases on the corrosion of supercritical carbon dioxide.

[0042] The CO 2 / SO 2 The mixed gas passes through a steam evaporator composed of a container 13 containing deionized water, a first heater 14, a first thermocouple 15 and a first temperature controller 16, and the temperature is controlled to 46°C, so that the water vapor content is controlled to 10%. A certain amount of water vapor can be carried, and the amount of water vapor carried is determined by the temperature of the deionized water.

[0043] After the mixed gas passes through the steam evaporator, an insulation device (such as an insulation sleeve, a heating belt, etc.) is installed on the outer surface of the delivery pipe 17 before it enters the reactor 19, so that its temperature is consistent with the temperature of the reactor 19, that is, 60°C, to prevent the water vapor carried in the mixed gas from condensing due to the decrease in temperature, thereby reducing the water vapor content in the actual test.

[0044] After the mixed gas passes through the steam evaporator described in claim 4, its pressure is reduced. In order to make the pressure in the reactor 19 reach above 8MPa (slightly higher than the critical pressure of carbon dioxide), a booster pump 12 is used for pressurization, and then the control valve 26 at the outlet of the reactor 19 is adjusted to make the pressure of the reactor 19 reach 10MPa, which is displayed by the fourth pressure gauge 25.

[0045] The sample 20 is vertically suspended on the sample rack 18 and placed in the reactor 19. The flow direction of the mixed gas will remain parallel to the main observation surface of the sample, which is consistent with the flow direction in the supercritical carbon dioxide delivery pipeline and can accurately simulate the actual working conditions. The reactor reaches the target temperature through the combined action of the preheating tube bundle 21, the second heater 22, the second thermocouple 23 and the second temperature controller 24. The pressure in the reactor is adjusted to the target pressure by adjusting the control valve 26 and displayed on the pressure gauge 25.

[0046] After the mixed gas flows out of the reactor 19, in order to prevent the acidic gas from causing harm to the human body and the atmosphere, a first-stage absorption solution tank 27 and a second-stage absorption solution tank 28 are used for continuous two-stage chemical treatment, and the absorption solution can be configured according to the characteristics of the impurity gas. The mixed gas at the outlet of the reactor 19 enters the first-stage absorption solution tank 27 through the control valve 26, and then is discharged after passing through the second-stage absorption solution tank 28. After the mixed gas flows out of the reactor 19, in order to prevent the acidic gas from causing harm to the human body and the atmosphere, a first-stage absorption solution tank 27 and a second-stage absorption solution tank 28 are used for continuous two-stage chemical treatment, and the absorption solution is 10% NaOH solution, the volume of the absorption solution tank is 50L, and the replacement cycle is 3d.

[0047] The present invention also provides a test method for a test device simulating corrosion of a supercritical carbon dioxide transmission pipeline, which is specifically as follows:

[0048] S1. Add sufficient deionized water into the container 13, seal it, and heat the deionized water to 46° C. using the first heater 14, the first thermocouple 15 and the first temperature controller 16; the temperature is determined by calculating the water vapor content and saturated vapor pressure in the mixed gas.

[0049] S2. Adjust the three-way valve 11 so that the argon cylinder 1 is connected to the reactor 19, open the first pressure reducing valve 7, open the control valve 26, and use argon to exhaust the air in the reactor 19. The time for introducing argon is determined by calculating the argon flow rate and the volume of the reactor (19). For example, when the volume of the reactor is 10L and the argon flow rate is 100mL / min, the time for introducing argon to deoxygenate is at least 100min.

[0050] S3, regulating the second temperature controller 24 so that the internal temperature of the reactor 19 is 60°C, and regulating the insulation tube 17 so that it is maintained at the same temperature as the temperature inside the reactor 19, i.e., 60°C.

[0051] S4, adjust the three-way valve 11 to connect the steam evaporator with the reactor 19, open the second pressure reducing valve 8 and the third pressure reducing valve 9, and control SO 2 The content is 5%, and the temperature of the first thermostat 16 is adjusted to 46° C. to obtain a water vapor content of 10%.

[0052] S5, start the gas booster pump 12 to pressurize the mixed gas carrying 10% water vapor to above 10 MPa, and adjust the control valve 26 at the outlet of the reactor 19 so that the pressure in the reactor 19 reaches 10 MPa, which is displayed by the fourth pressure gauge 25.

[0053] S6. The gas flowing out from the outlet of the reactor 19 is subjected to two-stage chemical treatment through the first-stage absorption solution tank 27 and the second-stage absorption solution tank 28 to avoid harm to personnel and air. The two-stage absorption solutions are both 10% NaOH solution, the volume of the absorption solution tank is 50L, and the replacement cycle is 3d.

[0054] S7. After the test is completed, step S2 is repeated to discharge the carbon dioxide gas in the reactor 19, and the second temperature controller 24 is turned off. After the temperature in the reactor 19 drops to room temperature, the sample is taken out for corrosion rate calculation, corrosion product analysis and other related analyses.

[0055] The above contents are only for explaining the technical idea of ​​the present invention and cannot be used to limit the protection scope of the present invention. Any changes made on the basis of the technical solution in accordance with the technical idea proposed by the present invention shall fall within the protection scope of the claims of the present invention.

Claims

1. An experimental device for simulating the corrosion of a supercritical carbon dioxide transportation pipeline, characterized in that, it includes: an argon gas cylinder (1), a carbon dioxide gas cylinder (2), an impurity gas cylinder (3), a gas mixer (10), a container (13) and a reaction kettle (19); the argon gas cylinder (1) is connected to the intake pipe at the lower part of the reaction kettle (19); the carbon dioxide gas cylinder (2) and the impurity gas cylinder (3) are both connected to the gas mixer (10), the gas mixer (10) is connected to the container (13) filled with deionized water through a pipeline, and a steam evaporator is arranged on the container (13); the outlet pipe of the container (13) is connected to the intake pipe of the reaction kettle (19); a sample rack (18) for hanging the test piece (20) is arranged inside the reaction kettle (19), and a heating unit is arranged outside it; an outlet pipe is arranged at the upper part of the reaction kettle (19); The impurity gas cylinder (3) is selected as SO 2 , and the gas is mixed by a gas mixer to control the content of SO 2 to be 5%; the steam evaporator includes a first heater (14), a first thermocouple (15) and a first temperature controller (16), the first heater (14) is arranged at the bottom of the container (13), the first thermocouple (15) is arranged inside the container (13), and the first temperature controller (16) is electrically connected to the first thermocouple (15); so that the water vapor content is controlled to be 10%; the heating unit includes a preheating tube bundle (21), a second heater (22), a second thermocouple (23) and a second temperature controller (24), the preheating tube bundle (21) is embedded in the inner cavity of the reaction kettle (19), the sample rack (18) is arranged inside the preheating tube bundle (21), the second heater (22) is embedded in the outer wall of the reaction kettle (19), the second thermocouple (23) is arranged inside the preheating tube bundle (21), and the second thermocouple (23) is electrically connected to the second temperature controller (24); the test piece (20) is vertically hung on the sample rack (18) and placed in the reaction kettle (19), and the flow direction of the mixed gas is parallel to the observation surface of the test piece.

2. An experimental device for simulating the corrosion of a supercritical carbon dioxide transportation pipeline according to claim 1, characterized in that, the argon gas cylinder (1) is connected to the reaction kettle (19) through a first pressure reducing valve (7) and a three-way valve (11).

3. An experimental device for simulating the corrosion of a supercritical carbon dioxide transportation pipeline according to claim 1, characterized in that, the carbon dioxide gas cylinder (2) and the impurity gas cylinder (3) are respectively connected to the gas mixer (10) through a second pressure reducing valve (8) and a third pressure reducing valve (9).

4. An experimental device for simulating the corrosion of a supercritical carbon dioxide transportation pipeline according to claim 1 or 3, characterized in that, a booster pump (12) is arranged on the outlet pipe of the container (13).

5. An experimental device for simulating the corrosion of a supercritical carbon dioxide transportation pipeline according to claim 1, characterized in that, the outlet pipe of the container (13) and the intake pipe of the reaction kettle (19) are connected through a three-way valve (11), and the intake pipe of the reaction kettle (19) is a heat-insulating pipe (17).

6. An experimental device for simulating the corrosion of a supercritical carbon dioxide transportation pipeline according to claim 1, characterized in that, A control valve (26) and a pressure gauge (25) are provided on the gas outlet pipe of the reactor (19).

7. An experimental device for simulating the corrosion of a supercritical carbon dioxide transportation pipeline according to claim 1, characterized in that, the gas outlet pipe of the reactor (19) is sequentially connected to a first-stage absorption solution tank (27) and a second-stage absorption solution tank (28), and the outlet of the second-stage absorption solution tank (28) is emptied.

8. A test method for an experimental device for simulating the corrosion of a supercritical carbon dioxide transportation pipeline according to any one of claims 1 to 6, characterized in that, it includes the following steps: S1. Add deionized water into the container (13), seal it, and heat the deionized water to the target temperature by using a steam evaporator; S2. Connect the argon gas cylinder (1) to the reactor (19), and use argon gas to discharge the air in the reactor (19); S3. Regulate the heating unit so that the internal temperature of the reactor (19) is the target temperature; S4. Connect the steam evaporator to the reactor (19), adjust the flow rates of various gases to control the ratio of the mixed gas, and regulate the water vapor content in the mixed gas; S5. Pass the mixed gas carrying water vapor into the reactor (19); S6. Carry out the corrosion test process of supercritical carbon dioxide; S7. After the test is completed, repeat step S2 to discharge the carbon dioxide gas in the reactor (19), turn off the heating unit, and after the temperature in the reactor (19) drops to room temperature, take out the specimen for relevant analysis.

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