CO2 phase conversion monitoring system and method for CO2 conveying pipeline

Abstract

The invention discloses a CO2 phase conversion dynamic monitoring system and method suitable for a CO2 conveying pipeline, and belongs to the technical field of CO2 capture, utilization and storage. The system comprises a gas supply system, a pressure control system, a phase change controller, a high-pressure loop system, a measuring device and a data processing device. According to the system, gas is supplied to two pieces of equipment in the phase change generation system through one gas supply system, transformation observation between different phase states is very comprehensive, and the research cost is saved. The pressure and temperature response conditions of CO2 phase change can be accurately and efficiently reflected by adjusting parameters such as pressure and temperature of the system.

Description

Technical Field

[0001] The present invention relates to CO 2 The capture, utilization and storage technology field, more specifically for CO 2 CO in pipelines 2 Phase transformation dynamic monitoring system and method. Background Art

[0002] Carbon capture, storage and utilization (CCUS) technology can store carbon dioxide emitted during the production process, or purify it and put it into new production processes for recycling. CCUS technology converts carbon dioxide into resources, generates economic benefits, and is beneficial to the environment. It is the only means so far that can significantly reduce greenhouse gas emissions from industrial processes. It is one of the key technologies for addressing global climate change and is highly valued by countries around the world.

[0003] CO 2 Pipelines are the key link in CCUS technology to connect the capture site with the storage or utilization site. 2 It can be transported in pipelines in gaseous, normal liquid, supercritical and dense phase states, which is determined by the temperature and pressure of the pipeline system. 2 The critical temperature and critical pressure of CO2 are 31℃ and 7.38MP respectively. During pipeline transportation, CO2 is easily affected by the ground temperature at the depth of the pipeline and the pressure and temperature changes along the pipeline, causing phase changes, which affects the transportation efficiency and cost. 2 In general liquid transportation, due to the influence of temperature changes and pressure drops along the pipeline, the working fluid is unstable, which can easily lead to gaseous CO 2 The formation of gas-liquid two-phase flow causes unstable working conditions and great difficulties in transportation. 2 Due to the high critical point, improper control of the transportation process can easily lead to phase change, which will affect the safe and stable operation of the pipeline. 2 During the commissioning process of the transmission pipeline, if the pressure difference is too large during pressure increase, problems such as pipeline vibration, air blockage, excessive temperature drop to produce dry ice, and additional pipe damage may occur.

[0004] Therefore, it is necessary to analyze the CO in pipelines under different environments. 2 The pressure response and temperature response of phase transformation are dynamically simulated and monitored to determine the appropriate transport parameters, but the existing technology lacks relevant monitoring technology. Summary of the invention

[0005] The object of the present invention is to provide a method suitable for CO 2 CO in pipelines 2 Phase transformation dynamic monitoring system and method.

[0006] In order to achieve the above technical objectives, the technical solution adopted by the present invention is as follows:

[0007] According to one aspect of the present invention, there is provided a 2 CO in pipelines 2 Phase transformation dynamic monitoring system, including:

[0008] Gas supply system;

[0009] A pressure control system receives CO from the gas supply system. 2 gas, and regulate CO 2 The pressure of the gas;

[0010] A phase change controller receives CO provided by the pressure control system. 2 gas, and for the CO 2 The gas provides a preset temperature gradient;

[0011] A high pressure loop system, wherein the high pressure loop system receives CO provided by the pressure control system 2 gas, and for the CO 2 The gas provides a preset pressure gradient;

[0012] A measuring device, the measuring device comprising a plurality of first temperature sensors and at least one first pressure sensor disposed at different positions in the phase change controller, and a plurality of second temperature sensors and a plurality of second pressure sensors disposed at different positions of the high pressure loop system;

[0013] A data processing device, wherein the data processing device collects data from the first temperature sensor, the first pressure sensor, the second temperature sensor, and the second pressure sensor, and generates a phase change pressure response model at each position at different temperatures based on the data from the first temperature sensor and the first pressure sensor, and generates a phase change temperature response model at each position at different pressures based on the data from the second temperature sensor and the second pressure sensor.

[0014] According to one embodiment of the present invention, the gas supply system includes CO 2 Gas cylinders, gas pressure reducing valves and connecting pipes.

[0015] According to one embodiment of the present invention, the pressure control system includes a booster pump, an autoclave and connecting pipelines.

[0016] According to one embodiment of the present invention, the phase change controller and the high-pressure loop system are arranged in two parallel branches downstream of the autoclave, and a flow meter is provided in each of the branches.

[0017] According to one embodiment of the present invention, the phase change controller includes a high-pressure container and a first temperature control mechanism, a plurality of the first temperature sensors are arranged at different positions inside the high-pressure container, and at least one first pressure sensor is arranged inside the high-pressure container.

[0018] According to one embodiment of the present invention, the first temperature control mechanism includes a shell forming a temperature control chamber accommodating the high pressure container, a resistance heating component adjacent to the high pressure container, and a refrigerant pipeline for introducing refrigerant into the temperature control chamber.

[0019] According to one embodiment of the present invention, the high pressure container comprises a transparent window.

[0020] According to one embodiment of the present invention, the high-pressure loop system includes a high-pressure resistant pipe and a second temperature control mechanism, and a plurality of the second temperature sensors and a plurality of the second pressure sensors are arranged at different axial measured positions of the high-pressure resistant pipe.

[0021] According to an embodiment of the present invention, the number of the second temperature sensors and the second pressure sensors is the same, and one second temperature sensor and one second pressure sensor are provided at each measured position.

[0022] According to an embodiment of the present invention, the number of the measured positions is determined according to the length of the high-pressure resistant pipe and the distance between adjacent measured positions is 1 to 3 meters.

[0023] According to one embodiment of the present invention, the second temperature control mechanism includes a water circulation machine and a circulation jacket, the circulation jacket is wrapped around the outside of the high-pressure resistant pipe, a water circulation pipeline is arranged inside the circulation jacket, the water circulation pipeline is connected to the water circulation machine, and the water circulation machine can adjust and control the temperature of the water in the water circulation pipeline.

[0024] According to an embodiment of the present invention, the high pressure resistant tube is provided with transparent windows, and the transparent windows are arranged at the measured positions and the number of the transparent windows is consistent with the number of the measured positions.

[0025] According to one embodiment of the present invention, the exhaust port of the phase change controller and the exhaust port of the high-pressure loop system are connected to the exhaust gas tank after being merged by two parallel exhaust branches, and a control valve is provided in each of the parallel exhaust branches.

[0026] According to one embodiment of the present invention, the operating temperature range of the high-pressure loop system is 0° C. to 80° C., and the operating pressure range is 0.01 MPa to 12 MPa.

[0027] According to one embodiment of the present invention, the operating temperature range of the phase change controller is -50°C to 100°C, and the operating pressure range is 0.01MPa to 12MPa.

[0028] According to another aspect of the present invention, there is provided a method for controlling the CO2 in a transmission pipeline by using the system as described above. 2 The method for dynamic monitoring of phase transformation comprises the following steps:

[0029] Step S1, introducing CO into the high pressure loop system 2 , monitor the pressure at each measured position and achieve the predetermined pressure gradient of the entire pipeline by setting the pressure;

[0030] Step S2, performing pressure response tests using the high pressure loop system at multiple different temperatures, and at each test temperature, performing pressure response tests on the CO in the high pressure loop system. 2 Dynamically adjust the pressure and monitor the pressure at each measured position;

[0031] Step S3, sorting out the phase change pressure response data at different temperatures in step S2 to obtain a pressure response model at each measured position;

[0032] Step S4: introducing CO into the phase change controller 2 , adjust the temperature of the phase change controller, monitor the temperature of each measured position, and realize a predetermined temperature gradient distribution in the container;

[0033] Step S5, performing temperature response tests respectively using the phase change controller for a plurality of different pressures, dynamically adjusting the temperature in the phase change controller at each test pressure, and monitoring the temperature at each tested position;

[0034] Step S6, sorting out the phase change temperature response data under different pressures in step S5 to obtain a temperature response model at each measured position.

[0035] According to one embodiment of the present invention, in step S1, the method for achieving the pressure gradient of the entire pipeline is: utilizing the pressure drop in the high-pressure loop and 2 The principle of increasing pressure drop as the injection flow rate increases is used to achieve a predetermined pressure gradient by setting the inlet pressure, inlet flow rate and pipeline length.

[0036] According to one embodiment of the present invention, in step S2, the temperature, inlet pressure and inlet flow of the high-pressure loop are coordinated and set to ensure that the gas-liquid equilibrium pressure at the set temperature is between the pipeline inlet pressure and the pipeline end pressure.

[0037] According to one embodiment of the present invention, in step S4, the method for achieving a predetermined temperature gradient distribution in the container is: obtaining the predetermined temperature gradient distribution by changing the temperature of a temperature control mechanism outside the container and controlling the size of the container.

[0038] According to one embodiment of the present invention, in step S5, at each test pressure, dynamically adjusting the temperature in the phase change controller includes: maintaining the pressure in the phase change controller at the selected test pressure, taking the corresponding gas-liquid equilibrium temperature as the highest temperature, gradually reducing the temperature in the phase change controller, and observing the liquid CO 2 Compress and liquefy, or gradually increase the temperature in the phase change controller with the corresponding gas-liquid equilibrium temperature as the lowest temperature, and observe the liquid CO 2 Expansion and gasification.

[0039] Due to the adoption of the above technical solution, the system and method provided by the present invention have at least one of the following beneficial effects compared with the prior art:

[0040] (1) The system supplies gas to two devices in the phase change generation system through a gas supply system, which makes it possible to observe the transition between different phases very comprehensively and saves research costs;

[0041] (2) By setting the variables of high-pressure loop temperature, inlet pressure, and inlet flow in the loop system, CO 2 The dynamic phase change under a fixed pressure gradient is observed and data is recorded and collected throughout the process. The experimental data is deeply analyzed through measurement and data processing, which accurately and efficiently reflects the CO 2 stress response;

[0042] (3) By controlling the temperature gradient in the phase change controller, CO 2 The dynamic phase change under a fixed temperature gradient is observed and data is recorded and collected throughout the process, and the experimental data is analyzed through measurement and data processing, which accurately and efficiently reflects the CO 2 The temperature response. BRIEF DESCRIPTION OF THE DRAWINGS

[0043] The accompanying drawings are used to provide a further understanding of the present invention and constitute a part of the specification. Together with the following specific embodiments, they are used to explain the present invention but do not constitute a limitation of the present invention. In the accompanying drawings:

[0044] Figure 1 is the phase diagram of pure carbon dioxide according to the prior art;

[0045] Figure 2 According to one embodiment of the present invention, a CO 2 CO in pipelines 2 Schematic diagram of the structure of the phase transformation dynamic monitoring system;

[0046] Figure 3 is a schematic structural diagram of a phase change controller according to an embodiment of the present invention;

[0047] Figure 4 Schematic diagram of the structure of a high-pressure loop system according to an embodiment of the present invention. DETAILED DESCRIPTION

[0048] The specific implementation of the present disclosure is described in detail below in conjunction with the accompanying drawings. It should be understood that the specific implementation described herein is only used to illustrate and explain the present disclosure, and is not used to limit the present disclosure.

[0049] In addition, reference to "embodiments" herein means that a particular feature, structure, or characteristic described in conjunction with the embodiments may be included in at least one embodiment of the present invention. The appearance of the phrase in various places in the specification does not necessarily refer to the same embodiment, nor is it an independent or alternative embodiment that is mutually exclusive with other embodiments. It is explicitly and implicitly understood by those skilled in the art that the embodiments described herein may be combined with other embodiments.

[0050] It will be understood by those skilled in the art that, unless otherwise defined, all terms (including technical terms and scientific terms) used herein have the same meaning as the general understanding of those skilled in the art to which this application belongs. It should also be understood that terms such as those defined in general dictionaries should be understood to have the same meaning as in the context of the prior art, and will not be interpreted with an idealized or overly formal meaning unless specifically defined as in the embodiments of this application.

[0051] Due to CO 2 The critical temperature and critical pressure of CO2 are 31℃ and 7.38MP respectively. During pipeline transportation, CO2 is easily affected by the ground temperature at the depth of the pipeline and the pressure and temperature changes along the pipeline, causing phase changes, which affects the transportation efficiency and cost. 2 In general liquid transportation, due to the influence of temperature changes and pressure drops along the pipeline, the working fluid is unstable, which can easily lead to gaseous CO 2 The formation of gas-liquid two-phase flow causes unstable working conditions and great difficulties in transportation. 2 Due to the high critical point, improper control of the transportation process can easily lead to phase change, which will affect the safe and stable operation of the pipeline. 2 During the commissioning process of the transmission pipeline, if the pressure difference is too large during pressure increase, problems such as pipeline vibration, air blockage, excessive temperature drop to produce dry ice, and additional pipe damage may occur.

[0052] In order to solve these problems and achieve CO 2 Safe and stable pipeline transportation requires CO 2 The pressure response and temperature response of pipeline transportation are analyzed and studied. Before that, it is necessary to understand the 2 basic properties.

[0053] Figure 1 The phase diagram of pure carbon dioxide according to the prior art is shown. It can be seen from the figure that the triple point (-56°C, 0.52MPa) and the critical point (7.38MPa, 31.04°C) are the same as those of pure carbon dioxide according to the prior art. 2 It is in a state of gas-solid equilibrium, that is, no matter how high the temperature is, there is no liquid phase. Pure CO 2 The phase diagram can be divided into five regions: supercritical gas region (pressure higher than 7.385MPa, temperature higher than 31.04℃); dense liquid region (pressure higher than 7.385MPa, temperature lower than 31.04℃ and higher than -56℃); general liquid region (pressure lower than 7.385MPa, temperature lower than 31.04℃ and higher than -56℃); solid region (temperature lower than -56℃); general gas region (temperature higher than -56℃). 2 After understanding the pressure response and temperature response characteristics of pipeline transportation, appropriate transportation pressure and temperature can be selected to ensure CO 2 The entire pipeline transportation process meets the set phase requirements.

[0054] Figure 2 According to one embodiment of the present invention, a CO 2 CO in pipelines 2 Schematic diagram of the structure of the phase transformation dynamic monitoring system, which can be used to comprehensively observe and monitor the transformation between different phases under a set pressure gradient or temperature gradient.

[0055] The system generally includes a gas supply system, a pressure control system, a phase change controller, a high-pressure loop system, a measuring device and a data processing device. Among them, the pressure control system receives CO from the gas supply system. 2 gas, and regulate CO 2 The gas pressure, the phase change controller receives the CO provided by the pressure control system 2 gas, and CO 2 The gas provides a preset temperature gradient, and the high-pressure loop system receives CO from the pressure control system. 2 gas, and CO 2The gas provides a preset pressure gradient, the measuring device includes a plurality of first temperature sensors and at least one first pressure sensor arranged at different positions in the phase change controller, and a plurality of second temperature sensors and a plurality of second pressure sensors arranged at different positions of the high-pressure loop system, the data processing device collects data from the first temperature sensor, the first pressure sensor, the second temperature sensor and the second pressure sensor, and generates a phase change pressure response model at each position at different temperatures based on the data from the first temperature sensor and the first pressure sensor, and generates a phase change temperature response model at each position under different pressures based on the data from the second temperature sensor and the second pressure sensor.

[0056] In a specific embodiment, Figure 2 As shown, the gas supply system includes CO 2 Gas cylinder 1, gas pressure reducing valve 2 and related connecting pipelines. 2 The gas cylinder 1 can be a high-pressure gas cylinder (pressure is generally 150-200 bar). The pressure control system includes a booster pump 3, an autoclave 5 and a connecting pipeline. The high-pressure gas cylinder is connected to the booster pump 3 by a high-pressure hose. A flow meter 4 can be set on the pipeline between the booster pump 3 and the autoclave 5 to monitor and control the CO entering the autoclave 5 and the entire main pipeline. 2 Flow rate. Two branches are arranged in parallel downstream of the autoclave 5, and the phase change controller 13 and the high-pressure loop system 10 are respectively arranged in one of the branches. A flow meter and a corresponding control valve can be provided in each branch, or when the flow meter 4 is provided on the main line, a flow meter (such as flow meter 8) can be provided only in one of the branches (such as the branch where the high-pressure loop system 10 is located). The exhaust port of the phase change controller 13 and the exhaust port of the high-pressure loop system 10 are connected to the exhaust gas tank 15 after being merged by two parallel exhaust branches, and a control valve can be provided in each parallel exhaust branch. Thus, one gas supply system can supply gas to two devices in the phase change generation system, comprehensively observe the transition between different phases, and save research costs.

[0057] Figure 3 FIG. 1 is a schematic diagram showing a phase change controller according to an embodiment of the present invention. Figure 2The structure of the phase change controller 13 is described in detail. The phase change controller 13 mainly includes a high-pressure container 13a and a first temperature control mechanism 13b. The pressure that the high-pressure container can withstand is greater than 15MPa. The high-pressure container 13a is a hollow tubular structure, and a space for accommodating carbon dioxide is formed inside it. The first temperature control mechanism 13b includes an outer shell that forms a control room for accommodating the high-pressure container 13a, a resistance heating component adjacent to the high-pressure container, and a refrigerant pipeline for introducing a refrigerant into the control room. The refrigerant can specifically be liquid nitrogen. The resistance heating component can include a plurality of resistance heating elements uniformly distributed around the circumference of the high-pressure container. The first temperature control mechanism 13b is used to control and adjust the temperature inside the high-pressure container 13a. A transparent window can also be provided on the high-pressure container 13a to facilitate observation of the CO in the high-pressure container 13a. 2 phase state.

[0058] A plurality of detected positions can be selected according to the size of the high-pressure container 13a, and the distance between adjacent detected positions can be controlled within 0.3 to 0.5 meters. Since the distances between different positions in the high-pressure container 13a and the heating component are different, there are temperature gradient changes at different positions in the high-pressure container 13a, and the temperature gradient changes are monitored by installing temperature sensors at different positions. As shown in the figure, the high-pressure container 13a has three detected positions P1, P2 and P3. Each detected position is provided with a temperature sensor ST1, and one of the detected positions is provided with a pressure sensor SP1. The data collected by the temperature sensor ST1 and the pressure sensor SP1 are sent to the data processing device 14. The operating temperature range of the phase change controller 13 is -50°C to 100°C, and the operating pressure range is 0.01MPa to 12MPa. When testing, the temperature adjustment function of the temperature control mechanism 13b is used to realize the set temperature gradient, dynamically adjust the temperature under the selected fixed pressure, observe the temperature and phase change at different positions, and collect relevant data.

[0059] Figure 4 FIG. 1 is a schematic diagram showing the structure of a high pressure loop system 10 according to an embodiment of the present invention. Figure 2The structure of the high-pressure loop system 10 is described in detail. The high-pressure loop system 10 generally includes a high-pressure resistant pipe 9 and a second temperature control mechanism. The high-pressure resistant pipe 9 adopts a pipe with a certain length, and the pressure that the high-pressure resistant pipe 9 can withstand is greater than 15MPa. The second temperature control mechanism includes a water circulation machine 12 and a circulation jacket 11, and the circulation jacket 11 is wrapped around the outside of the high-pressure resistant pipe 9. A water circulation pipeline is provided in the circulation jacket 11, and the water circulation pipeline is connected to the water circulation machine 12. The water circulation machine 12 can adjust and control the temperature of the water in the water circulation pipeline, thereby realizing the adjustment of the temperature in the high-pressure resistant pipe 9. The operating temperature range of the high-pressure loop system 10 is 0°C to 80°C, and the working pressure range is 0.01MPa to 12MPa.

[0060] A plurality of locations to be measured are selected on the high-pressure pipe 9 to set pressure sensors 6 and temperature sensors 7 to detect the temperature, pressure and phase conditions at different locations along the axial direction of the pipe. To this end, a transparent window is set opposite each location to make the CO at the location to be measured visible. 2 The phase state of the pressure sensor 6 and the temperature sensor 7 are visualized. The number of the measured positions can be determined according to the length of the high pressure pipe 9 and the distance between adjacent measured positions is 1 to 3 meters. The data collected by the pressure sensor 6 and the temperature sensor 7 are sent to the data processing device 14.

[0061] The data processing device 14 generates a phase change pressure response model at each position at different temperatures based on the data of the temperature sensor ST1 and the pressure sensor SP1, and generates a phase change temperature response model at each position at different pressures based on the data of the temperature sensor 7 and the pressure sensor 6.

[0062] The present invention also provides a method for utilizing the above system to control the CO 2 A method for dynamically monitoring phase transformation, the method comprising the following steps:

[0063] Step S1, introducing CO into the high pressure loop system 2 , monitor the pressure at each measured position and achieve the predetermined pressure gradient of the entire pipeline by setting the pressure;

[0064] Step S2, using the high pressure loop system to perform pressure response tests at multiple different temperatures, at each test temperature, the CO in the high pressure loop system is 2 Dynamically adjust the pressure and monitor the pressure at each measured position;

[0065] Step S3, sorting out the phase change pressure response data at different temperatures in step S2 to obtain a pressure response model at each measured position;

[0066] Step S4: introducing CO into the phase change controller 2, adjust the temperature of the phase change controller, monitor the temperature of each measured position, and realize a predetermined temperature gradient distribution in the container;

[0067] Step S5, performing temperature response tests respectively using a phase change controller for a plurality of different pressures, dynamically adjusting the temperature in the phase change controller at each test pressure, and monitoring the temperature at each tested position;

[0068] Step S6, sorting out the phase change temperature response data under different pressures in step S5 to obtain a temperature response model at each measured position.

[0069] Each step is described in detail below.

[0070] In step S1, the method for achieving the pressure gradient of the entire pipeline is to utilize the pressure drop in the high-pressure loop and 2 The principle of increasing pressure drop as the injection flow rate increases is used to achieve a predetermined pressure gradient by setting the inlet pressure, inlet flow rate, and pipeline length. Since there is a pressure drop in the high-pressure loop, and the pressure drop increases with the increase of the injection flow rate, the supercritical / liquid CO in the pipeline 2 After passing through the entire pipeline and falling below the critical pressure / gas-liquid equilibrium pressure, it will expand and vaporize.

[0071] In step S2, the temperature, inlet pressure, and inlet flow of the high-pressure loop need to be coordinated and set to ensure that the gas-liquid equilibrium pressure at the set temperature is between the pipeline inlet pressure and the pipeline end pressure. In step S2, multiple test temperatures are selected, and at each test temperature, the CO in the high-pressure loop system is adjusted by changing the inlet pressure and inlet flow of the high-pressure loop. 2 The pressure is dynamically adjusted, and the pressure and phase state of each measured position are monitored. When setting the high-pressure loop temperature, inlet pressure, and inlet flow, it is necessary to ensure that the pipeline can be in supercritical state, supercritical state to gas state, and gas state from beginning to end, or liquid state, liquid state to gas state, and gas state. It is necessary to ensure that the gas-liquid equilibrium pressure at the set temperature is between the pipeline inlet pressure and the pipeline end pressure. Such dynamic pressure adjustment is performed for each test temperature, and the temperature and pressure information of each position is collected. After processing these data, the pressure response model at each position can be obtained.

[0072] In step S3, the phase change pressure response data at different temperatures in step S2 are sorted to obtain the pressure response model at each measured position. The sensor output data includes the corresponding pressure or temperature, time and other information. The position information of the sensor in the pipeline can be determined according to the sensor number. The CO at the measured position is fitted using the state equation based on the pressure information measured by the pressure sensor at each measured position and the temperature information measured by the temperature sensor. 2The density of CO is plotted in a three-dimensional graph combined with position and time to represent the pressure response model of phase change. Based on this graph, it is possible to clearly and intuitively judge the 2 The phase state at different positions and times in the pipeline, and the influence of pressure gradient on the phase state.

[0073] In step S4, the method for achieving the predetermined temperature gradient distribution in the container is to obtain the predetermined temperature gradient distribution by changing the temperature of the temperature control mechanism outside the container and controlling the size of the container. The temperature gradient exists due to the different distances between different positions and the temperature control mechanism.

[0074] In step S5, the temperature response test is performed for a plurality of different pressures using the phase change controller. At each test pressure, the temperature in the phase change controller is dynamically adjusted, and the temperature and phase state of each tested position are monitored. In other words, a plurality of different pressures can be selected for temperature response tests, and the pressure is fixed and maintained during each test. Since the temperature of the tested point in the phase change controller is adjustable, the corresponding gas-liquid equilibrium temperature is used as the test starting temperature, and the temperature in the phase change controller is gradually reduced to observe the liquid CO 2 Compress and liquefy and collect pressure and temperature data, or gradually increase the temperature in the phase change controller with the corresponding gas-liquid equilibrium temperature as the lowest temperature to observe the liquid CO 2 The expansion and gasification situation is recorded and the pressure and temperature data are collected. After that, the set pressure is changed, the temperature is dynamically adjusted again and the relevant data is collected. By sorting and processing the data, the phase change situation along the temperature gradient can be obtained, and the phase change model can be obtained. Similar to step S3, the sensor output data includes the corresponding pressure or temperature, time and other information. The position information of the sensor in the pipeline can be determined according to the sensor number. Based on the pressure information measured by the pressure sensor and the temperature information measured by each temperature sensor, the state equation is used to fit the CO at the measured position. 2 The density of CO is plotted in a three-dimensional graph combined with position and time to represent the temperature response model of phase change. Based on this graph, it is clear and intuitive to judge the 2 The phase state at different positions and times in the pipeline, and the influence of temperature gradient on the phase state.

[0075] The system and method of the present invention are not only applicable to pure CO 2 Dynamic monitoring of the phase transformation of impurity gases can also be performed on CO 2 Dynamic monitoring of the phase transformation of impurity-containing gas 2 When dynamically monitoring the phase transformation of CO, it is only necessary to control the gas components provided to the pressure control system to contain a predetermined amount of impurities. 2 The transitions between different phases are observed very comprehensively.

[0076] The preferred embodiments of the present invention are described in detail above. However, the present invention is not limited to the specific details in the above embodiments. Within the technical concept of the present invention, a variety of simple modifications can be made to the technical solution of the present invention, and these simple modifications all belong to the protection scope of the present invention.

[0077] It should also be noted that the various specific technical features described in the above specific embodiments can be combined in any suitable manner without contradiction. In order to avoid unnecessary repetition, the present invention will not further describe various possible combinations.

[0078] In addition, various embodiments of the present invention may be arbitrarily combined, and as long as they do not violate the concept of the present invention, they should also be regarded as the contents disclosed by the present invention.

Claims

1. A CO2 phase transformation dynamic monitoring system suitable for a CO2 transmission pipeline, characterized in that: include: Gas supply system; A pressure control system, the pressure control system receives the CO2 gas from the gas supply system and adjusts the pressure of the CO2 gas; a phase change controller, the phase change controller receiving the CO2 gas provided by the pressure control system and providing a preset temperature gradient for the CO2 gas; A high-pressure loop system, wherein the high-pressure loop system receives the CO2 gas provided by the pressure control system and provides a preset pressure gradient for the CO2 gas; A measuring device, the measuring device comprising a plurality of first temperature sensors and at least one first pressure sensor disposed at different positions in the phase change controller, and a plurality of second temperature sensors and a plurality of second pressure sensors disposed at different positions of the high pressure loop system; A data processing device, wherein the data processing device collects data from the first temperature sensor, the first pressure sensor, the second temperature sensor, and the second pressure sensor, and generates a phase change pressure response model at each position at different temperatures based on the data from the first temperature sensor and the first pressure sensor, and generates a phase change temperature response model at each position at different pressures based on the data from the second temperature sensor and the second pressure sensor.

2. The system according to claim 1, characterized in that The gas supply system includes a CO2 gas cylinder, a gas pressure reducing valve and connecting pipelines.

3. The system according to claim 1, characterized in that The pressure control system comprises a booster pump, an autoclave and connecting pipelines.

4. The system according to claim 3, characterized in that The phase change controller and the high-pressure loop system are arranged in two parallel branches downstream of the autoclave, and a flow meter is arranged in each branch.

5. The system according to claim 4, characterized in that The phase change controller includes a high-pressure container and a first temperature control mechanism. A plurality of the first temperature sensors are arranged at different positions inside the high-pressure container, and at least one of the first pressure sensors is arranged inside the high-pressure container.

6. The system according to claim 5, characterized in that The first temperature control mechanism includes a shell forming a temperature control chamber for accommodating the high-pressure container, a resistance heating component adjacent to the high-pressure container, and a refrigerant pipeline for introducing refrigerant into the temperature control chamber.

7. The system according to claim 5, characterized in that The high pressure container includes a transparent window.

8. The system according to claim 4, characterized in that The high-pressure loop system includes a high-pressure resistant pipe and a second temperature control mechanism, and a plurality of the second temperature sensors and a plurality of the second pressure sensors are arranged at different axial measured positions of the high-pressure resistant pipe.

9. The system according to claim 8, characterized in that The number of the second temperature sensors and the second pressure sensors is the same, and each measured position is provided with a second temperature sensor and a second pressure sensor.

10. The system according to claim 9, characterized in that The number of the measured positions is determined according to the length of the high-pressure resistant pipe and the distance between adjacent measured positions is 1 to 3 meters.

11. The system according to claim 8, characterized in that The second temperature control mechanism includes a water circulation machine and a circulation jacket. The circulation jacket is wrapped around the outside of the high-pressure resistant pipe. A water circulation pipeline is arranged in the circulation jacket. The water circulation pipeline is connected to the water circulation machine. The water circulation machine can adjust and control the temperature of the water in the water circulation pipeline.

12. The system according to claim 8, characterized in that The high-pressure resistant tube is provided with transparent windows, and the transparent windows are arranged at the measured positions and the number of the transparent windows is consistent with the number of the measured positions.

13. The system according to claim 4, characterized in that The exhaust port of the phase change controller and the exhaust port of the high-pressure loop system are connected to the exhaust gas tank after being merged by two parallel exhaust branches, and a control valve is provided in each of the parallel exhaust branches.

14. The system according to claim 1, characterized in that The operating temperature range of the high-pressure loop system is 0°C to 80°C, and the operating pressure range is 0.01MPa to 12MPa.

15. The system according to claim 1, characterized in that The operating temperature range of the phase change controller is -50°C to 100°C, and the operating pressure range is 0.01MPa to 12MPa.

16. A method for dynamically monitoring the phase transformation of CO2 in a transmission pipeline using the system according to any one of claims 1 to 15, characterized in that: The following steps are involved: Step S1, introducing CO2 into the high-pressure loop system, monitoring the pressure at each measured position, and achieving a predetermined pressure gradient of the entire pipeline by setting the pressure; Step S2, performing pressure response tests using the high-pressure loop system at multiple different temperatures, dynamically adjusting the pressure of CO2 in the high-pressure loop system at each test temperature, and monitoring the pressure at each tested position; Step S3, sorting out the phase change pressure response data at different temperatures in step S2 to obtain a pressure response model at each measured position; Step S4, introducing CO2 into the phase change controller, adjusting the temperature of the phase change controller, monitoring the temperature of each measured position, and achieving a predetermined temperature gradient distribution in the container; Step S5, performing temperature response tests respectively using the phase change controller for a plurality of different pressures, dynamically adjusting the temperature in the phase change controller at each test pressure, and monitoring the temperature at each tested position; Step S6, sorting out the phase change temperature response data under different pressures in step S5 to obtain a temperature response model at each measured position.

17. The method according to claim 16, characterized in that In step S1, the method for achieving the pressure gradient of the entire pipeline is: utilizing the principle that there is a pressure drop in the high-pressure loop and the pressure drop increases with the increase of the CO2 injection flow rate, and achieving the predetermined pressure gradient by setting the inlet pressure, inlet flow rate and pipeline length.

18. The method according to claim 16, characterized in that In step S2, the temperature, inlet pressure and inlet flow rate of the high-pressure loop are coordinated and set to ensure that the gas-liquid equilibrium pressure at the set temperature is between the pipeline inlet pressure and the pipeline end pressure.

19. The method according to claim 16, characterized in that In step S4, the method for achieving the predetermined temperature gradient distribution in the container is: obtaining the predetermined temperature gradient distribution by changing the temperature of the temperature control mechanism outside the container and controlling the size of the container.

20. The method according to claim 16, characterized in that In step S5, at each test pressure, the temperature in the phase change controller is dynamically adjusted, including: maintaining the pressure in the phase change controller at the selected test pressure, gradually lowering the temperature in the phase change controller with the corresponding gas-liquid equilibrium temperature as the highest temperature, and observing the compression and liquefaction of the liquid CO2, or gradually raising the temperature in the phase change controller with the corresponding gas-liquid equilibrium temperature as the lowest temperature, and observing the expansion and gasification of the liquid CO2.

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