Experimental system for supercritical carbon dioxide rock corrosion and use method

Abstract

The invention relates to an experimental system for supercritical carbon dioxide rock corrosion and a use method.The experimental system comprises a corrosion container, the corrosion container is used for storing a saturated carbon dioxide aqueous solution, a top opening of the corrosion container is connected with a sealing cover, and a heating assembly and a rock sample placing frame are arranged in the corrosion container; the top of the rock sample placing frame is located above the liquid level of the saturated carbon dioxide aqueous solution, the bottom of the rock sample placing frame is immersed in the saturated carbon dioxide aqueous solution, the heating assembly is arranged on the peripheral wall of the corrosion container and connected with the controller, and the controller regulates and controls the temperature of the heating assembly. The corrosion container is connected with the carbon dioxide gas conveying unit through a conveying pipe; the carbon dioxide gas conveying unit comprises a gas source storage tank and a gas outlet; the gas booster pump assembly is connected with the gas outlet through a pipeline, and the gas booster pump assembly is connected with the conveying pipe. According to the invention, rocks can be corroded in a supercritical state and a carbon dioxide solution at the same time.

Description

Technical Field

[0001] The present invention relates to the technical field of rock corrosion experiments, and more specifically, to an experimental system and method for supercritical carbon dioxide rock corrosion. Background Art

[0002] The rock supercritical carbon dioxide corrosion experiment is an experimental method for studying the physical and chemical properties of rocks, mainly by analyzing the strength performance of specimens through testing the chemical composition changes in rocks. This experiment has wide applications in fields such as materials science, chemical engineering, and geological exploration.

[0003] In the carbon dioxide geological sequestration environment, rock-supercritical carbon dioxide-carbon dioxide groundwater solution coexists. Supercritical carbon dioxide can dissolve certain minerals in rocks, such as carbonate rocks, which may cause changes in the physical and chemical properties of rocks; while the carbon dioxide groundwater solution will react with certain minerals in rocks (such as silicates), and new mineral phases may be generated. These new minerals may have different physical and chemical properties, thus affecting the properties of rocks. Therefore, it is necessary to study the rock properties while the supercritical carbon dioxide-carbon dioxide groundwater solution coexists to provide true and reliable research data for materials science, chemical engineering, and geological exploration. However, there is no device in the prior art that can simultaneously provide a corrosion environment for rock specimens in the supercritical phase and liquid phase at the same temperature and pressure state. Therefore, it is of great significance to provide an experimental system for supercritical carbon dioxide rock corrosion to study the property changes of rocks in the carbon dioxide geological sequestration environment. Summary of the Invention

[0004] Aiming at the deficiencies of the above prior art, the purpose of the present invention is to provide an experimental system and method for supercritical carbon dioxide rock corrosion, which can enable rocks to be corroded simultaneously in the supercritical state and carbon dioxide solution at the same temperature and pressure state for the carbon dioxide geological sequestration environment.

[0005] To solve the above technical problems, the present invention adopts the following technical solutions: The present invention provides an experimental system for supercritical carbon dioxide rock corrosion, including a corrosion container for storing a saturated carbon dioxide aqueous solution. The top of the corrosion container is open and connected with a sealing cover. Inside the corrosion container, there is a heating component and a rock sample placement rack. The top of the rock sample placement rack is above the liquid level of the saturated carbon dioxide aqueous solution, and the bottom of the rock sample placement rack is immersed in the saturated carbon dioxide aqueous solution. The heating component is arranged on the peripheral wall of the corrosion container and connected to a controller. The controller regulates the temperature of the heating component to provide conditions for maintaining the supercritical state of carbon dioxide. The corrosion container is connected to a carbon dioxide gas delivery unit through a delivery pipe. The carbon dioxide gas delivery unit includes: A gas source storage tank for supplying carbon dioxide gas, and the gas source storage tank has a gas outlet; A gas booster pump assembly for providing conditions for maintaining the supercritical state of carbon dioxide. The gas booster pump assembly is connected to the gas outlet through a pipeline, and the gas booster pump assembly is connected to the delivery pipe.

[0006] Preferably, the gas booster pump assembly includes a gas booster pump and a buffer container. The buffer container is arranged between the gas booster pump and the corrosion container. The inlet of the buffer container is connected to the gas booster pump through a pipeline, and the outlet of the buffer container is connected to the corrosion container through a delivery pipe.

[0007] Preferably, both the corrosion container and the buffer container are made of a high-temperature, high-pressure and corrosion-resistant alloy.

[0008] Preferably, a pressure gauge and a needle-type pressure control valve for regulating the carbon dioxide pressure are arranged on the delivery pipe.

[0009] Preferably, the corrosion container includes two independent upper and lower first corrosion chambers and second corrosion chambers. Both the first corrosion chamber and the second corrosion chamber store a saturated carbon dioxide aqueous solution. The rock sample placement rack is at least provided with two, and each rock sample placement rack is respectively arranged in the first corrosion chamber and the second corrosion chamber. The sealing cover includes a first sealing cover and a second sealing cover. The first sealing cover is threadedly connected to the open top of the first corrosion chamber, and the second sealing cover is threadedly connected to the open bottom of the second corrosion chamber. It includes a transmission pipe and a transfer pipe. Both the transmission pipe and the transfer pipe are connected to the gas booster pump assembly through pipelines. The transmission pipe passes through the first sealing cover and is connected to the first corrosion chamber, and the transfer pipe is connected to the second corrosion chamber.

[0010] Preferably, the first sealing cover has a first sealing body threadedly connected to the first corrosion chamber, and the second sealing cover has a second sealing body threadedly connected to the second corrosion chamber. Both the first sealing body and the second sealing body are sleeved with a first sealing ring and a second sealing ring up and down.

[0011] Preferably, the distance between the first sealing ring and the second sealing ring is 5 cm to 5.2 cm.

[0012] Preferably, threaded interfaces are provided at both the inlet ends and the outlet ends of all the pipelines, and all the pipelines are externally wrapped with Teflon wires.

[0013] The present invention also provides a method for using an experimental system for supercritical carbon dioxide rock corrosion, comprising the following steps: Place the rock sample on the rock sample placement rack, and fill the corrosion container with saturated carbon dioxide aqueous solution so that the lower part of the rock sample is immersed in the saturated carbon dioxide aqueous solution; Then open the gas storage tank, send the carbon dioxide in the gas storage tank into the gas booster pump for pressurization, and the pressurized carbon dioxide is sent into the corrosion container through the delivery pipe; Regulate the heating temperature of the heating component through the controller so that the pressurized carbon dioxide gas sent into the corrosion container is transformed into supercritical carbon dioxide, thereby placing the rock sample on the rock sample placement rack in a supercritical phase and liquid phase environment.

[0014] Compared with the prior art, the beneficial effects of the present invention are: The experimental system for supercritical carbon dioxide rock corrosion provided by the present invention can conduct rock corrosion simulation experiments for carbon dioxide geological storage environments, and solves the drawback that existing devices cannot simulate rock corrosion in a carbon dioxide geological storage environment under the same temperature and pressure conditions.

[0015] During the experiment, the carbon dioxide gas is pressurized by the gas booster pump assembly and then sent into the corrosion container through the delivery pipe, so that the carbon dioxide sent into the corrosion container has a pressure of 7.38 MPa to reach the supercritical state. The temperature of the heating component is regulated through the controller to heat the pressurized carbon dioxide sent into the corrosion container, so that the carbon dioxide sent into the corrosion container can reach the temperature of 31.1 °C to become the supercritical state. Since saturated carbon dioxide solution is filled in the corrosion container in advance before filling pressurized carbon dioxide into the corrosion container, and the lower part of the rock sample is immersed in the saturated carbon dioxide solution, then pressurized carbon dioxide is filled into the corrosion container, and the temperature of the pressurized carbon dioxide is adjusted, so that when the carbon dioxide becomes supercritical, the corrosion container realizes the simulation of the carbon dioxide geological storage environment, overcoming the defect that the existing devices cannot corrode the rock simultaneously in the liquid phase and the supercritical carbon dioxide gas phase.

[0016] In the present invention, a buffer container is provided. It is not only for storing the high-pressure carbon dioxide gas pressurized by the gas booster pump in the buffer container, but also for ensuring that the pressurized carbon dioxide gas can be fed into the corrosion container at a stable pressure. Description of the Drawings

[0017] Figure 1 It is a schematic diagram of the overall structure of a supercritical carbon dioxide rock corrosion and curing test device under high temperature and high pressure proposed by the present invention.

[0018] Figure 2 It is a schematic diagram of the structure of the corrosion container.

[0019] Figure 3 It is a schematic diagram of the structure of the high-pressure sealing cover.

[0020] Figure 4 It is a schematic diagram of the structure of the buffer container.

[0021] Figure 5 It is a schematic diagram of the structure of the gas booster pump (front view).

[0022] Figure 6 It is a schematic diagram of the structure of the gas booster pump (rear view).

[0023] Figure 7 It is a schematic diagram of the structure of the carbon dioxide gas source.

[0024] Figure 8 It is a schematic diagram of the structure of the controller, temperature controller, and resistance heating element.

[0025] Reference Signs 1. Corrosion container; 101. Second sealing cover; 102. First pressure gauge; 103. First needle-type pressure regulating valve; 2. First sealing cover; 201. First sealing body; 202. First sealing ring; 203. Second sealing ring; 204. Second needle-type pressure regulating valve; 205. Second pressure gauge; 206. First inlet pipe; 207. High-pressure gas screw interface; 3. Buffer container; 301. Pressure buffer tank; 302. First high-pressure interface screw; 303. High-pressure gas three-way valve; 304. Second high-pressure interface screw; 305. Second inlet pipe; 4. Gas booster pump; 401. Booster cylinder block; 402. Driving cylinder block; 403. Low-pressure air inlet; 404. Third inlet pipe; 405. High-pressure air outlet; 5. Gas source storage tank; 501. Gas pressure reducing valve; 502. Gas source switch ball valve; 503. High-concentration carbon dioxide gas cylinder; 6. Controller, 601. Temperature controller, 602. Resistance heating element. Detailed Embodiments

[0026] The following is a detailed description of the specific embodiments of the present invention. It should be understood that the protection scope of the present invention is not limited by the specific embodiments. Based on the embodiments of the present invention, all other embodiments obtained by those of ordinary skill in the art without creative efforts belong to the protection scope of the present invention. The experimental methods described in the embodiments of the present invention are all conventional methods unless otherwise specified.

[0027] Existing rock corrosion experimental systems all conduct corrosion research by immersing granite in a high-pressure reaction kettle filled with supercritical carbon dioxide. For the test device in the present invention, considering the coexistence state of rock-supercritical CO2-CO2 groundwater solution in the carbon dioxide geological storage environment, and conducting corrosion experiments on the rock in two environments is closer to the actual environment.

[0028] Aiming at the deficiencies of the above-mentioned existing technologies, the purpose of the present invention is to provide an experimental system and method for supercritical carbon dioxide rock corrosion, which can enable the rock to be corroded simultaneously in the supercritical state and carbon dioxide solution in the carbon dioxide geological storage environment.

[0029] As Figures 1 to 8 shown, the present invention provides an experimental system for supercritical carbon dioxide rock corrosion, including a corrosion container 1, which is used to store saturated carbon dioxide aqueous solution, and the top of the corrosion container 1 is connected with a sealing cover in an open manner. A heating component and a rock sample placement rack are arranged inside the corrosion container 1. The top of the rock sample placement rack is above the liquid level of the saturated carbon dioxide aqueous solution, and the bottom of the rock sample placement rack is immersed in the saturated carbon dioxide aqueous solution. The heating component is arranged on the peripheral wall of the corrosion container 1 and is connected with a controller 6. The controller 6 regulates the temperature of the heating component to provide conditions for maintaining the supercritical state of carbon dioxide, so that the temperature of the heating component after regulation can reach 31.1°C, the temperature for carbon dioxide to reach the supercritical state, when carbon dioxide is sent into the corrosion container 1. The corrosion container 1 is connected with a carbon dioxide gas delivery unit through a delivery pipe. The carbon dioxide gas delivery unit includes: A gas source storage tank 5 for supplying carbon dioxide gas, and the gas source storage tank 5 has a gas outlet; among them, the gas source storage tank 5 includes a high-concentration carbon dioxide gas cylinder 503, a gas pressure reducing valve 501 and a gas source switch ball valve 502. A pipeline is connected to the top of the high-concentration carbon dioxide gas cylinder 503, and a gas source switch ball valve 502 and a gas pressure reducing valve 501 are arranged on the pipeline near the output end. The gas outlet of the gas source storage tank 5 is the output end of the pipeline connected to the gas source storage tank 5.

[0030] The gas booster pump assembly is connected to the gas outlet (pipeline output end) through a pipeline. The gas booster pump assembly is connected to the delivery pipe. The gas booster pump assembly is used to make the carbon dioxide fed into the corrosion container 1 reach a pressure of 7.38 MPa at the supercritical state.

[0031] Among them, the gas booster pump assembly includes a gas booster pump 4. The gas booster pump 4 includes a booster cylinder block 401 and a drive cylinder block 402. One end of the booster cylinder block 401 is connected to the drive cylinder block 402. One end of the drive cylinder block 402 is provided with a low-pressure air inlet 403. The low-pressure air inlet 403 is connected to the gas source storage tank 5 through a third inlet pipe 404. The drive cylinder block 402 is provided with a high-pressure air outlet 405. The high-pressure air outlet 405 is connected to the delivery pipe through a second inlet pipe 305.

[0032] Specifically, the gas booster pump assembly includes a gas booster pump 4 and a buffer container 3. The buffer container 3 is arranged between the gas booster pump 4 and the corrosion container 1. The inlet of the buffer container 3 is connected to the gas booster pump 4 through a pipeline. The outlet of the buffer container 3 is connected to the corrosion container 1 through a delivery pipe.

[0033] The buffer container 3 includes a pressure buffer tank 301, a first high-pressure interface screw 302, a high-pressure gas three-way valve 303, a second high-pressure interface screw 304, and a second inlet pipe 305. Among them, the top outlet of the pressure buffer tank 301 is connected to a pipeline through the first high-pressure interface screw 302. This pipeline is connected to an outlet of the high-pressure gas three-way valve 303. The second high-pressure interface screw 304 is arranged on an inlet of the high-pressure gas three-way valve 303. The second high-pressure interface screw 304 is threadedly connected to the second inlet pipe 305. The other outlet of the high-pressure gas three-way valve 303 is connected to the corrosion container 1 through a delivery pipe.

[0034] Specifically, both the corrosion container 1 and the buffer container 3 are made of a high-temperature, high-pressure and corrosion-resistant alloy.

[0035] The purpose is to ensure that the materials of the buffer container 3 and the corrosion container 1 themselves will not be corroded by CO2 during long-term corrosion tests, resulting in the pollution of the specimen by the corrosion products of the metal material. Both the buffer container 3 and the corrosion container 1 are high-temperature corrosion-resistant alloys, and the alloy material number is GH4161.

[0036] Specifically, a pressure gauge and a needle-type pressure control valve for regulating the size of the carbon dioxide pressure are provided on the delivery pipe. The pressure gauge includes a first pressure gauge 102 and a second pressure gauge 205. The needle-type pressure control valve includes a first needle-type pressure regulating valve 103 and a second needle-type pressure regulating valve 204.

[0037] Specifically, the corrosion container 1 includes two independent upper and lower first corrosion chambers and second corrosion chambers, and saturated carbon dioxide aqueous solutions are stored in both the first corrosion chamber and the second corrosion chamber. The rock sample placement racks are provided with at least two, and each rock sample placement rack is respectively arranged in the first corrosion chamber and the second corrosion chamber. The sealing cover includes a first sealing cover 2 and a second sealing cover 101. The first sealing cover 2 is threadedly connected to the top opening of the first corrosion chamber, and the second sealing cover 101 is threadedly connected to the bottom opening of the second corrosion chamber. The conveying pipe includes a transmission pipe and a transfer pipe. Both the transmission pipe and the transfer pipe are connected to the gas booster pump assembly through pipelines. The transmission pipe is connected to the high-pressure gas screw interface 207 at the end of the first introduction pipe 206, penetrates through the first sealing cover 2 and is connected to the first corrosion chamber, and the transfer pipe is connected to the second corrosion chamber. A second needle-type pressure regulating valve 204 and a second pressure gauge 205 are also connected to the first introduction pipe 206, and a first needle-type pressure regulating valve 103 and a first pressure gauge 102 are also connected to the transfer pipe.

[0038] Specifically, the first sealing cover 2 has a first sealing body 201 threadedly connected to the first corrosion chamber, and the second sealing cover 101 has a second sealing body threadedly connected to the second corrosion chamber. A first sealing ring 202 and a second sealing ring 203 are sleeved on the first sealing body 201 and the second sealing body up and down.

[0039] Specifically, the distance between the first sealing ring 202 and the second sealing ring 203 is 5 cm to 5.2 cm.

[0040] The first sealing ring 202 is arranged at the middle position of the first sealing body 201 or the second sealing body, and the second sealing ring 203 is arranged at the threaded end of the first sealing body 201 or the second sealing body, so as to make the connection between the first sealing cover 2 and the first corrosion chamber or the second sealing cover 101 and the second corrosion chamber closer.

[0041] Specifically, threaded interfaces are provided at both the inlet end and the outlet end of all the pipelines, and all the pipelines are externally wrapped with polytetrafluoroethylene wires.

[0042] The threads at the pipeline interfaces can ensure the connection of the interfaces and replacement after damage. The polytetrafluoroethylene wire wrapping protects the pipelines from CO2 corrosion and also has wear-resistant properties.

[0043] The present invention provides a method for using an experimental system for supercritical carbon dioxide rock corrosion, including the following steps: Place the rock sample on the rock sample placement rack, and fill the corrosion container 1 with saturated carbon dioxide aqueous solution so that the lower part of the rock sample is immersed in the saturated carbon dioxide aqueous solution; Then, open the gas source storage tank 5, send the carbon dioxide in the gas source storage tank 5 into the gas booster pump 4 for pressurization, and send the pressurized carbon dioxide into the corrosion container 1 through the delivery pipe; Regulate the heating temperature of the heating component through the controller 6 so that the pressurized carbon dioxide gas sent into the corrosion container 1 is transformed into supercritical carbon dioxide, and thus the rock samples on the rock sample rack are placed in the supercritical phase and liquid phase environment.

[0044] The controller 6 includes a temperature controller 601, and the temperature controller 601 is connected with a resistance heating sheet 602 for providing a constant temperature heat source for the corrosion container 1. The heating component is the resistance heating sheet 602. Set the required temperature through the temperature controller 601 and provide a stable temperature through the resistance heating sheet 602.

[0045] Obviously, those skilled in the art can make various changes and modifications to the present invention without departing from the spirit and scope of the present invention. Thus, if these modifications and variations of the present invention fall within the scope of the claims of the present invention and its equivalent technologies, the present invention is also intended to include these changes and modifications.

Claims

1. An experimental system for supercritical carbon dioxide rock corrosion, comprising a corrosion container (1), characterized in that, The corrosion container (1) is used to store an aqueous solution saturated with carbon dioxide. The top of the corrosion container (1) is open and connected with a sealing cover. Inside the corrosion container (1), there are a heating component and a rock sample placement rack. The heating component is arranged on the peripheral wall of the corrosion container (1) and connected to a controller (6). The controller (6) regulates the temperature of the heating component to provide conditions for maintaining the supercritical state of carbon dioxide after regulation. The corrosion container (1) is connected to a carbon dioxide gas delivery unit through a delivery pipe. The carbon dioxide gas delivery unit includes: A gas source storage tank (5) for supplying carbon dioxide gas, and the gas source storage tank (5) has a gas outlet; A gas booster pump assembly for providing conditions for maintaining the supercritical state of carbon dioxide. The gas booster pump assembly is connected to the gas outlet through a pipeline, and the gas booster pump assembly is connected to the delivery pipe.

2. The experimental system for supercritical carbon dioxide rock corrosion according to claim 1, characterized in that, The gas booster pump assembly includes a gas booster pump (4) and a buffer container (3). The buffer container (3) is arranged between the gas booster pump (4) and the corrosion container (1). The inlet of the buffer container (3) is connected to the gas booster pump (4) through a pipeline, and the outlet of the buffer container (3) is connected to the corrosion container (1) through a delivery pipe.

3. An experimental system for supercritical carbon dioxide rock corrosion according to claim 2, characterized in that, Both the corrosion container (1) and the buffer container (3) are made of a high-temperature, high-pressure and corrosion-resistant alloy.

4. An experimental system for supercritical carbon dioxide rock corrosion according to claim 1, characterized in that, A pressure gauge and a needle-type pressure control valve for regulating the carbon dioxide pressure are provided on the delivery pipe.

5. An experimental system for supercritical carbon dioxide rock corrosion according to claim 1, characterized in that, The corrosion container (1) includes two independent upper and lower first corrosion chambers and second corrosion chambers. Saturated carbon dioxide aqueous solutions are stored in both the first corrosion chamber and the second corrosion chamber. The rock sample placement rack is provided with at least two, and each rock sample placement rack is respectively arranged in the first corrosion chamber and the second corrosion chamber. The sealing cover includes a first sealing cover (2) and a second sealing cover (101). The first sealing cover (2) is threadedly connected to the top opening of the first corrosion chamber, and the second sealing cover (101) is threadedly connected to the bottom opening of the second corrosion chamber. The delivery pipe includes a transmission pipe and a transfer pipe. Both the transmission pipe and the transfer pipe are connected to the gas booster pump assembly through pipelines. The transmission pipe penetrates through the first sealing cover (2) and is connected to the first corrosion chamber, and the transfer pipe is connected to the second corrosion chamber.

6. The experimental system for supercritical carbon dioxide rock corrosion according to claim 5, characterized in that, The first sealing cover (2) has a first sealing body (201) threadedly connected to the first corrosion chamber. The second sealing cover (101) has a second sealing body threadedly connected to the second corrosion chamber. The first sealing body (201) and the second sealing body are both sleeved with a first sealing ring (202) and a second sealing ring (203) up and down.

7. An experimental system for supercritical carbon dioxide rock corrosion according to claim 5, characterized in that, The distance between the first sealing ring (202) and the second sealing ring (203) is 5 cm to 5.2 cm.

8. An experimental system for supercritical carbon dioxide rock corrosion according to claim 5, characterized in that, Threaded interfaces are provided at both the inlet end and the outlet end of all the pipelines, and a polytetrafluoroethylene wire wrapping is provided outside all the pipelines.

9. The method for using an experimental system for supercritical carbon dioxide rock corrosion according to claim 1, characterized in that, Including the following steps: Place the rock sample on the rock sample placement rack, and fill the corrosion container (1) with a saturated carbon dioxide aqueous solution so that the lower part of the rock sample is immersed in the saturated carbon dioxide aqueous solution; Then open the gas source storage tank (5), send the carbon dioxide in the gas source storage tank (5) into the gas booster pump (4) for pressurization, and send the pressurized carbon dioxide into the corrosion container (1) through the delivery pipe; Regulate the heating temperature of the heating component through the controller so that the pressurized carbon dioxide gas sent into the corrosion container (1) is transformed into supercritical carbon dioxide, thereby placing the rock samples on the rock sample rack in a supercritical phase and liquid phase environment.

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