An experimental system and method for supercritical carbon dioxide rock corrosion

Abstract

The present invention relates to an experimental system for supercritical carbon dioxide rock corrosion and a method for using the same. The experimental system includes a corrosion container for storing a saturated carbon dioxide aqueous solution, the top of the corrosion container being open and connected to a sealing cover, a heating assembly and a rock sample rack being provided inside the corrosion container, the top of the rock sample rack being located above the liquid level of the saturated carbon dioxide aqueous solution, and the bottom of the rock sample rack being immersed in the saturated carbon dioxide aqueous solution, the heating assembly being provided on the peripheral wall of the corrosion container and connected to a controller that regulates the temperature of the heating assembly, the corrosion container being connected to a carbon dioxide gas delivery unit via a delivery pipe, the carbon dioxide gas delivery unit comprising: a gas source storage tank having a gas outlet; a gas booster pump assembly being connected to the gas outlet via a pipeline, and the gas booster pump assembly being connected to the delivery pipe. The present invention enables rock to be corroded simultaneously in a supercritical state and in a carbon dioxide solution.

Description

Technical Field

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

[0002] The supercritical carbon dioxide (SCCO) corrosion test is an experimental method used to study the physical and chemical properties of rocks. It primarily analyzes the strength of samples by measuring changes in the chemical composition of the rock. This experiment has a wide range of applications in materials science, chemical engineering, and geological exploration.

[0003] In a CO2 geological storage environment, rock, supercritical CO2, and CO2 groundwater coexist. Supercritical CO2 can dissolve certain minerals in the rock, such as carbonates, which may cause changes in the rock's physical and chemical properties. The CO2 groundwater reacts with certain minerals in the rock (such as silicates), potentially generating new mineral phases. These new minerals may have different physical and chemical properties, thus affecting the rock's properties. Therefore, it is necessary to simultaneously study rock properties in a supercritical CO2-CO2 groundwater coexistence state in order to provide reliable research data for materials science, chemical engineering, and geological exploration. However, there is no device in the prior art that can simultaneously provide rock samples for corrosion in supercritical and liquid phases at the same temperature and pressure. Therefore, it is of great significance to provide an experimental system for supercritical CO2 rock corrosion to study the changes in rock properties in a CO2 geological storage environment. Summary of the Invention

[0004] In view of the above-mentioned deficiencies in the prior art, the purpose of the present invention is to provide an experimental system and method for using supercritical carbon dioxide rock corrosion. The experimental system can corrode rocks in a supercritical state and a carbon dioxide solution at the same temperature and pressure in a carbon dioxide geological storage environment.

[0005] In order to solve the above technical problems, the present invention adopts the following technical solutions:

[0006] The present invention provides an experimental system for supercritical carbon dioxide rock corrosion, comprising a corrosion container for storing a saturated carbon dioxide aqueous solution, the top of the corrosion container being open and connected to a sealing cover, a heating component and a rock sample rack being provided inside the corrosion container, the top of the rock sample rack being located above the liquid level of the saturated carbon dioxide aqueous solution, and the bottom of the rock sample rack being immersed in the saturated carbon dioxide aqueous solution, the heating component being provided on the peripheral wall of the corrosion container and connected to a controller, the controller regulating the temperature of the heating component so that the regulated temperature of the heating component provides conditions for maintaining a supercritical state of carbon dioxide, the corrosion container being connected to a carbon dioxide gas delivery unit via a delivery pipe, the carbon dioxide gas delivery unit comprising:

[0007] A gas source storage tank is used to supply carbon dioxide gas, and the gas source storage tank has a gas outlet;

[0008] The gas booster pump assembly is used to provide 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.

[0009] 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, and the air inlet of the buffer container is connected to the gas booster pump through a pipeline, and the air outlet of the buffer container is connected to the corrosion container through a delivery pipe.

[0010] Preferably, the corrosion container and the buffer container are both made of high-temperature-resistant, pressure-resistant and corrosion-resistant alloy.

[0011] Preferably, the delivery pipe is provided with a pressure gauge and a needle-type pressure-control valve for regulating the pressure of carbon dioxide.

[0012] Preferably, the corrosion container includes two upper and lower independent first corrosion chambers and second corrosion chambers, and the first corrosion chamber and the second corrosion chamber both store saturated carbon dioxide aqueous solution, at least two rock sample placement racks are provided, 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 top opening of the first corrosion chamber, and the second sealing cover is threadedly connected to the bottom opening of the second corrosion chamber, including a transmission pipe and a transmission pipe, the transmission pipe and the transmission pipe are both 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 transmission pipe is connected to the second corrosion chamber.

[0013] Preferably, the first sealing cover has a first sealing body threadedly connected to the first corrosion chamber, the second sealing cover has a second sealing body threadedly connected to the second corrosion chamber, and the first sealing body and the second sealing body are both covered with a first sealing ring and a second sealing ring.

[0014] Preferably, the distance between the first sealing ring and the second sealing ring is 5 cm to 5.2 cm.

[0015] Preferably, the inlet and outlet ends of all the pipelines are provided with threaded interfaces, and the outsides of all the pipelines are covered with polytetrafluoroethylene.

[0016] The present invention also provides a method for using a supercritical carbon dioxide rock corrosion experimental system, comprising the following steps:

[0017] The rock sample is placed on a rock sample placement rack, and a saturated carbon dioxide aqueous solution is filled into the corrosion container so that the lower part of the rock sample is immersed in the saturated carbon dioxide aqueous solution;

[0018] Then, the gas source storage tank is opened, and the carbon dioxide in the gas source storage tank is sent to the gas booster pump for pressurization, and the pressurized carbon dioxide is sent to the corrosion container through the delivery pipe;

[0019] The heating temperature of the heating component is regulated by a controller so that the pressurized carbon dioxide gas fed into the corrosion container is converted into supercritical carbon dioxide, thereby placing the rock sample on the rock sample placement rack in a supercritical phase and liquid phase environment.

[0020] Compared with the prior art, the present invention has the following beneficial effects:

[0021] The supercritical carbon dioxide rock corrosion experimental system provided by the present invention can perform rock corrosion simulation experiments in a carbon dioxide geological storage environment, solving the problem that existing devices cannot simulate the carbon dioxide geological storage environment to perform rock corrosion simulation experiments under the same temperature and pressure conditions.

[0022] During the experiment, carbon dioxide gas is pressurized by a gas booster pump assembly and then sent into the corrosion container through a delivery pipe so that the carbon dioxide sent into the corrosion container has a supercritical pressure of 7.38 MPa. The temperature of the heating assembly is regulated by a controller to heat the pressurized carbon dioxide sent into the corrosion container so that the carbon dioxide sent into the corrosion container can reach a supercritical temperature of 31.1°C. Before the pressurized carbon dioxide is filled into the corrosion container, a saturated carbon dioxide solution is filled into the corrosion container in advance, and the lower part of the rock sample is immersed in the saturated carbon dioxide solution. The pressurized carbon dioxide is then 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 device in the prior art cannot corrode rocks in the liquid phase and supercritical carbon dioxide gas phase at the same time.

[0023] The buffer container is provided in the present invention not only to deliver the high-pressure carbon dioxide gas pressurized by the gas booster pump into the buffer container for storage, but also to ensure that the pressurized carbon dioxide gas can be delivered to the corrosion container at a stable pressure. BRIEF DESCRIPTION OF THE DRAWINGS

[0024] Figure 1 This is a schematic diagram of the overall structure of a supercritical carbon dioxide rock corrosion maintenance test device under high temperature and high pressure environment proposed by the present invention.

[0025] Figure 2 Schematic diagram of the corrosion container.

[0026] Figure 3 It is a schematic diagram of the high-pressure sealing cover structure.

[0027] Figure 4 Schematic diagram of the buffer container structure.

[0028] Figure 5 This is a schematic diagram of the gas booster pump structure (front).

[0029] Figure 6 Schematic diagram of the gas booster pump structure (back).

[0030] Figure 7 Schematic diagram of the carbon dioxide gas source structure.

[0031] Figure 8 It is a structural diagram of the controller, temperature controller and resistance heating plate.

[0032] Reference numerals

[0033] 1. Corrosion container; 101. Second sealing cover; 102. First pressure gauge; 103. First needle pressure regulating valve; 2. First sealing cover; 201. First sealing body; 202. First sealing ring; 203. Second sealing ring; 204. Second needle 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; 402, drive cylinder; 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 cylinder; 6, controller, 601, temperature controller, 602, resistance heating plate. DETAILED DESCRIPTION

[0034] The specific embodiments of the present invention are described in detail below, but it should be understood that the scope of protection of the present invention is not limited by the specific embodiments. Based on the embodiments of the present invention, all other embodiments obtained by ordinary technicians in this field without making creative work are within the scope of protection of the present invention. The experimental methods described in the embodiments of the present invention are all conventional methods unless otherwise specified.

[0035] Existing rock corrosion experimental systems all conduct corrosion research by immersing granite in a high-pressure reactor filled with supercritical carbon dioxide. The experimental device in the present invention mainly takes into account the coexistence of rock and supercritical CO2-CO2 groundwater solution in the geological storage environment of carbon dioxide. Conducting corrosion experiments on rocks in two environments at the same time is closer to the actual environment.

[0036] In view of the above-mentioned deficiencies in the prior art, the purpose of the present invention is to provide an experimental system and method for using supercritical carbon dioxide rock corrosion, which can corrode rocks in a supercritical state and a carbon dioxide solution simultaneously in a carbon dioxide geological storage environment.

[0037] like Figures 1 to 8As shown, the present invention provides an experimental system for supercritical carbon dioxide rock corrosion, including a corrosion container 1, wherein the corrosion container 1 is used to store a saturated carbon dioxide aqueous solution, and the top of the corrosion container 1 is open and connected to a sealing cover, and a heating component and a rock sample rack are provided inside the corrosion container 1, wherein the top of the rock sample rack is located above the liquid surface of the saturated carbon dioxide aqueous solution, and the bottom of the rock sample rack is immersed in the saturated carbon dioxide aqueous solution, the heating component is provided on the peripheral wall of the corrosion container 1 and connected to a controller 6, and the controller 6 regulates the temperature of the heating component so that the temperature of the heating component after regulation provides a condition for maintaining the supercritical state of carbon dioxide, so that the carbon dioxide fed into the corrosion container 1 can reach a temperature of 31.1°C to become a supercritical state, and the corrosion container 1 is connected to a carbon dioxide gas delivery unit through a delivery pipe, and the carbon dioxide gas delivery unit includes:

[0038] The gas source storage tank 5 is used to supply carbon dioxide gas, and the gas source storage tank 5 has a gas outlet; 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, wherein the top of the high-concentration carbon dioxide gas cylinder 503 is connected to a pipeline, and a gas source switch ball valve 502 and a gas pressure reducing valve 501 are provided on the pipeline near the output end. The gas outlet of the gas source storage tank 5 is the output end of the pipeline to which the gas source storage tank 5 is connected.

[0039] The gas booster pump assembly is connected to the gas outlet (pipeline output end) through a pipeline, and the gas booster pump assembly is connected to the delivery pipe. The gas booster pump assembly allows the carbon dioxide sent into the corrosion container 1 to have a supercritical pressure of 7.38 MPa.

[0040] The gas booster pump assembly includes a gas booster pump 4, which includes a booster cylinder 401 and a drive cylinder 402. One end of the booster cylinder 401 is connected to the drive cylinder 402. One end of the drive cylinder 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 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.

[0041] 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, and the air inlet of the buffer container 3 is connected to the gas booster pump 4 through a pipeline, and the air outlet of the buffer container 3 is connected to the corrosion container 1 through a delivery pipe.

[0042] 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, wherein the top outlet of the pressure buffer tank 301 is connected to the pipeline through the first high-pressure interface screw 302, and the 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, and 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.

[0043] Specifically, the corrosion container 1 and the buffer container 3 are both made of high-temperature-resistant, pressure-resistant and corrosion-resistant alloy.

[0044] The purpose is to ensure that the materials of buffer container 3 and corrosion container 1 themselves will not be corroded by CO2 during long-term corrosion tests, resulting in the corrosion products of the metal materials contaminating the samples. Both buffer container 3 and corrosion container 1 are high-temperature corrosion-resistant alloys, and the alloy material number is GH4161.

[0045] Specifically, the delivery pipe is provided with a pressure gauge and a needle pressure control valve for regulating the carbon dioxide pressure. The pressure gauge includes a first pressure gauge 102 and a second pressure gauge 205 , and the needle pressure control valve includes a first needle pressure regulating valve 103 and a second needle pressure regulating valve 204 .

[0046] Specifically, the corrosion container 1 includes two independent upper and lower first and second corrosion chambers, each of which stores a saturated carbon dioxide aqueous solution. At least two rock sample racks are provided, each of which is located in the first and second corrosion chambers. 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 transmission pipe, each of which is connected to the gas booster pump assembly via a pipeline. The transmission pipe is connected to the high-pressure gas screw interface 207 at the end of the first inlet pipe 206, passes through the first sealing cover 2 and is connected to the first corrosion chamber, and the transmission pipe is connected to the second corrosion chamber. The first inlet pipe 206 is also connected to a second needle pressure regulating valve 204 and a second pressure gauge 205, and the transmission pipe is also connected to the first needle pressure regulating valve 103 and a first pressure gauge 102.

[0047] 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. The first sealing body 201 and the second sealing body are both provided with a first sealing ring 202 and a second sealing ring 203 on the upper and lower parts.

[0048] Specifically, the distance between the first sealing ring 202 and the second sealing ring 203 is 5 cm to 5.2 cm.

[0049] The first sealing ring 202 is arranged in the middle 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 first sealing cover 2 and the first corrosion chamber or the second sealing cover 101 and the second corrosion chamber tighter.

[0050] Specifically, the inlet and outlet ends of all the pipelines are provided with threaded interfaces, and the outsides of all the pipelines are covered with polytetrafluoroethylene.

[0051] The threads at the pipeline interface can ensure the interface connection and replacement after damage. The PTFE sheath protects the pipeline from CO2 corrosion and has wear-resistant properties.

[0052] The present invention provides a method for using a supercritical carbon dioxide rock corrosion experimental system, comprising the following steps:

[0053] Place the rock sample on a 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;

[0054] Then, the gas source storage tank 5 is opened, and the carbon dioxide in the gas source storage tank 5 is fed into the gas booster pump 4 for pressurization, and the pressurized carbon dioxide is fed into the corrosion container 1 through the delivery pipe;

[0055] The heating temperature of the heating assembly is regulated by the controller 6 so that the pressurized carbon dioxide gas fed into the corrosion container 1 is converted into supercritical carbon dioxide, thereby placing the rock sample on the rock sample placement rack in a supercritical phase and liquid phase environment.

[0056] The controller 6 includes a temperature controller 601, which is connected to a resistance heating plate 602 for providing a constant temperature heat source for the corrosion container 1. The heating component is the resistance heating plate 602. The desired temperature is set by the temperature controller 601, and the resistance heating plate 602 provides a stable temperature.

[0057] Obviously, those skilled in the art may make various changes and modifications to the present invention without departing from the spirit and scope of the present invention. Thus, if such modifications and variations of the present invention fall within the scope of the claims and their equivalents, the present invention is intended to include such modifications and variations.

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 a saturated carbon dioxide aqueous solution, and the top of the corrosion container (1) is open and connected to a sealing cover. A heating component and a rock sample placement rack are provided inside the corrosion container (1). The top of the rock sample placement rack is located above the liquid surface 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 provided on the peripheral wall of the corrosion container (1) and is connected to a controller (6). The controller (6) regulates the temperature of the heating component so that the temperature of the heating component after regulation provides a condition for maintaining a supercritical state of carbon dioxide. The corrosion container (1) is connected to a carbon dioxide gas delivery unit through a delivery pipe. The carbon dioxide gas delivery unit comprises: A gas source storage tank (5) is used to supply carbon dioxide gas, and the gas source storage tank (5) has a gas outlet; A gas booster pump assembly, used to provide conditions for maintaining the supercritical state of carbon dioxide, the gas booster pump assembly is connected to the gas outlet via a pipeline, and the gas booster pump assembly is connected to the delivery pipe; The corrosion container (1) includes two upper and lower independent first corrosion chambers and second corrosion chambers, and saturated carbon dioxide aqueous solution is stored in the first corrosion chamber and the second corrosion chamber. At least two rock sample placement racks are provided, and each rock sample placement rack is respectively provided 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 transmission pipe. The transmission pipe and the transmission pipe are both connected to the gas booster pump assembly through a pipeline. The transmission pipe passes through the first sealing cover (2) and is connected to the first corrosion chamber, and the transmission pipe is connected to the second corrosion chamber.

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

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

4. The supercritical carbon dioxide rock corrosion experimental system according to claim 1, characterized in that: The delivery pipe is provided with a pressure gauge and a needle-type pressure-control valve for regulating the pressure of carbon dioxide.

5. The supercritical carbon dioxide rock corrosion experimental system according to claim 1, characterized in that: 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. The first sealing body (201) and the second sealing body are both provided with a first sealing ring (202) and a second sealing ring (203) on the upper and lower sides.

6. The supercritical carbon dioxide rock corrosion experimental system according to claim 1, characterized in that: The distance between the first sealing ring (202) and the second sealing ring (203) is 5 cm to 5.2 cm.

7. The supercritical carbon dioxide rock corrosion experimental system according to claim 1, characterized in that: The inlet and outlet ends of all the pipelines are provided with threaded interfaces, and the outsides of all the pipelines are covered with polytetrafluoroethylene wire.

8. The method for using the supercritical carbon dioxide rock corrosion experimental system according to claim 1, characterized in that: The steps include: The rock sample is placed on a rock sample placement rack, and a saturated carbon dioxide aqueous solution is filled into the corrosion container (1) so that the lower part of the rock sample is immersed in the saturated carbon dioxide aqueous solution; Then, the gas source storage tank (5) is opened, and the carbon dioxide in the gas source storage tank (5) is sent to the gas booster pump (4) for pressurization, and the pressurized carbon dioxide is sent to the corrosion container (1) through the delivery pipe; The heating temperature of the heating component is regulated by a controller so that the pressurized carbon dioxide gas fed into the corrosion container (1) is converted into supercritical carbon dioxide, thereby placing the rock sample on the rock sample placement rack in a supercritical phase and liquid phase environment.

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