CO2 phase conversion monitoring system and method for CO2 transport pipelines

Abstract

The application discloses a CO2 phase state 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 ring channel system, a measuring device and a data processing device. The system supplies gas to two devices in the phase change system through a gas supply system, is very comprehensive in observing the conversion between different phase states, and saves research cost. The pressure and temperature response conditions of CO2 phase change can be accurately and efficiently reflected by adjusting the pressure, temperature and other parameters of the system.

Description

TECHNICAL FIELD

[0001] The present application relates to the field of CO2 capture, utilization and storage, and more particularly to a CO2 phase transformation dynamic monitoring system and method for a CO2 transport pipeline. BACKGROUND

[0002] Carbon capture, utilization and storage (CCUS) technology can store carbon dioxide discharged in the production process, or recycle and reuse in new production processes after purification. CCUS technology recycles carbon dioxide resources, generates economic benefits, and is conducive to environmental protection. It is currently the only means to significantly reduce industrial process greenhouse gas emissions, and is one of the key technologies to address global climate change, which has been highly valued by countries around the world.

[0003] CO2 pipeline is a key link of CCUS technology connecting capture sites and storage or utilization sites. Technically, CO2 can be transported in gaseous, general liquid, supercritical and dense phase states, which is determined by the temperature and pressure of the pipeline system. Since the critical temperature and critical pressure of CO2 are 31℃ and 7.38MP respectively, in the process of pipeline transportation, carbon dioxide is easily affected by the ground temperature at the pipeline burial depth and the pressure and temperature changes along the line, and the phase state changes, affecting the transportation efficiency and cost. If CO2 is transported in general liquid state, due to the influence of temperature change and pressure drop along the pipeline, the working medium is unstable, and gaseous CO2 is easily formed, resulting in gas-liquid two-phase flow, thereby causing unstable working conditions and great difficulty for transportation. Unlike natural gas pipelines, CO2 has a higher critical point, and improper control during transportation can easily cause phase change, affecting the safe and stable operation of the pipeline. For supercritical CO2 transport pipeline commissioning process, if the pressure difference is too large during pressure increase, problems such as pipeline vibration, gas plug, dry ice due to excessive temperature reduction, and additional pipe damage may occur.

[0004] Therefore, it is necessary to dynamically simulate and monitor the pressure response and temperature response of CO2 phase transformation in the transport pipeline in different environments in order to determine appropriate transport parameters, but there is currently a lack of related monitoring technology in the prior art. SUMMARY

[0005] The purpose of the present application is to provide a CO2 phase transformation dynamic monitoring system and method suitable for CO2 transport pipelines.

[0006] To achieve the above technical purpose, the technical solution adopted by the present application is as follows:

[0007] According to one aspect of the present application, a CO2 phase transformation dynamic monitoring system suitable for a CO2 transport pipeline is provided, comprising:

[0008] a gas supply system;

[0009] a pressure control system receiving the CO2 gas from the gas supply system and adjusting the pressure of the CO2 gas;

[0010] a phase transition controller receiving the CO2 gas from the pressure control system and providing a preset temperature gradient for the CO2 gas;

[0011] a high-pressure loop system receiving the CO2 gas from the pressure control system and providing a preset pressure gradient for the CO2 gas;

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

[0013] a data processing device collecting data of the first temperature sensors, the first pressure sensors, the second temperature sensors and the second pressure sensors, and generating a phase transition pressure response model at different temperatures for each position based on the data of the first temperature sensors and the first pressure sensors, and generating a phase transition temperature response model at different pressures for each position based on the data of the second temperature sensors and the second pressure sensors.

[0014] According to one embodiment of the present application, the gas supply system comprises a CO2 gas cylinder, a gas pressure reducing valve and connecting pipelines.

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

[0016] According to one embodiment of the present application, the phase transition 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 of the branches.

[0017] According to one embodiment of the present application, the phase transition controller comprises a high-pressure resistant container, a first temperature control mechanism, and a plurality of first temperature sensors arranged at different positions inside the high-pressure resistant container, and at least one first pressure sensor arranged inside the high-pressure resistant container.

[0018] According to one embodiment of the present application, the first temperature control mechanism comprises a shell forming a temperature control chamber accommodating the high-pressure resistant container, a resistance heating component adjacent to the high-pressure resistant container, and a refrigerant pipeline through which a refrigerant is introduced into the temperature control chamber.

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

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

[0021] According to one embodiment of the present application, the number of the second temperature sensors and the second pressure sensors is consistent, and one second temperature sensor and one second pressure sensor are arranged at each measurement position.

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

[0023] According to one embodiment of the present application, the second temperature control mechanism comprises a water circulating machine and a circulating jacket, the circulating jacket is wrapped outside the high-pressure resistant pipe, a water circulating pipeline is arranged in the circulating jacket, the water circulating pipeline is in communication with the water circulating machine, and the water circulating machine can adjust and control the temperature of the water in the water circulating pipeline.

[0024] According to one embodiment of the present application, the high-pressure resistant pipe is provided with transparent windows, the transparent windows are arranged at the measurement positions and the number of the transparent windows is consistent with the number of the measurement positions.

[0025] According to one embodiment of the present application, the exhaust port of the phase change controller and the exhaust port of the high-pressure loop system are connected to a waste gas tank through two parallel exhaust branches, and a control valve is arranged in each of the parallel exhaust branches.

[0026] According to one embodiment of the present application, the working temperature range of the high-pressure loop system is 0-80℃, and the working pressure range is 0.01-12 MPa.

[0027] According to one embodiment of the present application, the working temperature range of the phase change controller is -50-100℃, and the working pressure range is 0.01-12 MPa.

[0028] According to another aspect of the present application, a method for dynamically monitoring the CO2 phase state conversion of a conveying pipeline by using the system as described above is provided, comprising the following steps:

[0029] Step S1, CO2 is introduced into the high-pressure loop system, the pressure at each measurement position is monitored, and a predetermined pressure gradient of the whole pipeline is achieved by setting the pressure;

[0030] Step S2, pressure response tests are respectively performed on a plurality of different temperatures by using the high-pressure loop system, at each test temperature, the pressure of CO2 in the high-pressure loop system is dynamically adjusted, and the pressure at each measurement position is monitored;

[0031] Step S3, the phase transition pressure response data at different temperatures in step S2 is arranged to obtain the pressure response model at each measured position;

[0032] Step S4, CO2 is introduced into the phase transition controller, the temperature of the phase transition controller is adjusted, the temperature of each measured position is monitored, and the predetermined temperature gradient distribution in the container is realized;

[0033] Step S5, temperature response tests are carried out on the phase transition controller for a plurality of different pressures, the temperature in the phase transition controller is dynamically adjusted at each test pressure, and the temperature of each measured position is monitored;

[0034] Step S6, the phase transition temperature response data at different pressures in step S5 is arranged to obtain the temperature response model at each measured position.

[0035] According to an embodiment of the present application, in step S1, the method for realizing the pressure gradient of the whole pipeline is: using the principle that the pressure drop of the high-pressure ring channel exists and increases with the increase of the CO2 injection flow, realizing the predetermined pressure gradient by setting the inlet pressure, the inlet flow and the pipeline length.

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

[0037] According to an embodiment of the present application, in step S4, the method for realizing the predetermined temperature gradient distribution in the container is: changing the temperature of the temperature control mechanism outside the container and controlling the size of the container to obtain the predetermined temperature gradient distribution.

[0038] According to an embodiment of the present application, in step S5, the dynamic adjustment of the temperature in the phase transition controller at each test pressure includes: maintaining the pressure in the phase transition controller at the selected test pressure, taking the corresponding gas-liquid equilibrium temperature as the highest temperature, gradually reducing the temperature in the phase transition controller, and observing the compression and liquefaction of liquid CO2, or taking the corresponding gas-liquid equilibrium temperature as the lowest temperature, gradually increasing the temperature in the phase transition controller, and observing the expansion and gasification of liquid CO2.

[0039] Due to the above technical solutions, the system and method provided by the present application 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 transition system through a gas supply system, which is very comprehensive for observing the transition between different phases, and saves research cost;

[0041] (2) Set the variable high-pressure loop temperature, inlet pressure, and inlet flow rate in the loop system, and the dynamic phase change of CO2 under a fixed pressure gradient can be observed and data recorded and collected. Through measurement and data processing, the experimental data is analyzed in depth, and the pressure response of CO2 is accurately and efficiently reflected.

[0042] (3) Control the temperature gradient in the phase change controller, and the dynamic phase change of CO2 under a fixed temperature gradient can be observed and data recorded and collected. Through measurement and data processing, the experimental data is analyzed, and the temperature response of CO2 is accurately and efficiently reflected. BRIEF DESCRIPTION OF DRAWINGS

[0043] The accompanying drawings are included to provide a further understanding of the present application, and constitute a part of the specification, illustrate embodiments of the present application and explain the principles of the present application, but are not intended to limit the present application. In the drawings:

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

[0045] Figure 2 is a structural schematic diagram of a CO2 phase state conversion dynamic monitoring system suitable for a CO2 delivery pipeline according to an embodiment of the present application;

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

[0047] Figure 4 is a structural schematic diagram of a high-pressure loop system according to an embodiment of the present application. DETAILED DESCRIPTION

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

[0049] In addition, the phrase "embodiment" mentioned herein means that the specific features, structures or characteristics described in conjunction with the embodiment can be included in at least one embodiment of the present application. The appearance of this phrase in various places in the specification does not necessarily mean the same embodiment, nor is it an independent or alternative embodiment to other embodiments. Those skilled in the art explicitly and implicitly understand that the embodiments described herein can be combined with other embodiments.

[0050] Those skilled in the art will understand that, unless otherwise defined, all terms (including technical and scientific terms) used herein have the same meaning as commonly understood by one of ordinary skill in the art to which this application belongs. It will be further understood that terms, such as those defined in commonly used dictionaries, should be interpreted as having a meaning that is consistent with their meaning in the context of the relevant art and will not be interpreted in an idealized or overly formal sense unless expressly so defined herein.

[0051] Since the critical temperature and critical pressure of CO2 are 31℃ and 7.38 MPa respectively, in the process of pipeline transportation, carbon dioxide is easily affected by the ground temperature at the buried depth of the pipeline and the pressure and temperature changes along the line to change the phase state, affecting the transportation efficiency and cost. If CO2 is transported in general liquid state, due to the influence of temperature change and pressure drop along the pipeline, the working medium is unstable, and gaseous CO2 is easily formed, resulting in gas-liquid two-phase flow, thereby causing unstable working conditions and great difficulty for transportation. Unlike natural gas pipelines, CO2 has a higher critical point, and improper control during transportation process can easily cause phase change, affecting the safe and stable operation of the pipeline. For the commissioning process of supercritical CO2 transportation pipeline, if the pressure difference is too large during pressure increase, problems such as pipeline vibration, gas jam, excessive temperature drop to produce dry ice, and additional pipe damage may occur.

[0052] In order to solve these problems and realize the safe and stable pipeline transportation of CO2, it is necessary to analyze and study the pressure response and temperature response of CO2 pipeline transportation. Before that, the basic properties of CO2 must be understood.

[0053] Figure 1 The phase diagram of pure carbon dioxide according to the prior art is shown. As can be seen from the figure, the triple point is -56℃ and 0.52 MPa, and the critical point is 7.38 MPa and 31.04℃. When the pressure is lower than 0.7 MPa, CO2 is in gas-solid equilibrium state, i.e. no matter how high the temperature is, there is no liquid phase. The pure CO2 phase diagram can be divided into five regions: supercritical gas region (pressure higher than 7.385 MPa and temperature higher than 31.04℃); dense liquid region (pressure higher than 7.385 MPa and temperature lower than 31.04℃ and higher than -56℃); general liquid region (pressure lower than 7.385 MPa and temperature lower than 31.04℃ and higher than -56℃); solid region (temperature lower than -56℃); and general gas region (temperature higher than -56℃). Therefore, after studying the pressure response and temperature response characteristics of CO2 pipeline transportation, appropriate transportation pressure and temperature can be selected to ensure that the CO2 pipeline transportation meets the set phase state requirements throughout the whole process.

[0054] Figure 2is a structural schematic diagram of a CO2 phase transition dynamic monitoring system suitable for CO2 transportation pipeline according to an embodiment of the present application, using which the transition between different phases under a set pressure gradient or temperature gradient can be observed and monitored very comprehensively.

[0055] The system generally comprises a gas supply system, a pressure control system, a phase transition controller, a high-pressure loop system, a measuring device and a data processing device. The pressure control system receives CO2 gas from the gas supply system and adjusts the pressure of the CO2 gas, the phase transition controller receives the CO2 gas provided by the pressure control system and provides a preset temperature gradient for the CO2 gas, 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, the measuring device comprises a plurality of first temperature sensors and at least one first pressure sensor arranged at different positions in the phase transition controller, and a plurality of second temperature sensors and a plurality of second pressure sensors arranged at different positions in the high-pressure loop system, and the data processing device collects data of the first temperature sensors, the first pressure sensor, the second temperature sensors and the second pressure sensors, and generates a phase transition pressure response model at each position under different temperatures based on the data of the first temperature sensors and the first pressure sensor, and generates a phase transition temperature response model at each position under different pressures based on the data of the second temperature sensors and the second pressure sensors.

[0056] In a specific embodiment, as shown in Figure 2 The gas supply system comprises a CO2 gas cylinder 1, a gas pressure reducing valve 2 and related connecting pipelines. The CO2 gas cylinder 1 can be a high-pressure gas cylinder (the pressure is generally 150-200 bar). The pressure control system comprises a booster pump 3, a high-pressure kettle 5 and connecting pipelines. The high-pressure gas cylinder is connected to the booster pump 3 by a high-pressure hose. A flow meter 4 can be arranged on the pipeline between the booster pump 3 and the high-pressure kettle 5, so as to monitor and control the flow of CO2 into the high-pressure kettle 5 and the entire main pipeline. Two branches are arranged in parallel downstream of the high-pressure kettle 5, and the phase transition controller 13 and the high-pressure loop system 10 are arranged in one of the branches respectively. A flow meter and a corresponding control valve can be arranged in each branch, or in the case that a flow meter 4 is arranged on the main pipeline, a flow meter (such as flow meter 8) can be arranged in only one of the branches (such as the branch in which the high-pressure loop system 10 is arranged). The exhaust outlets of the phase transition controller 13 and the high-pressure loop system 10 are connected to a waste gas tank 15 after being merged by two parallel exhaust branches, and a control valve can be arranged in each parallel exhaust branch. In this way, one gas supply system can supply gas to two devices in the phase transition system, and the transition between different phases can be observed comprehensively, saving research costs.

[0057] Figure 3A structural schematic diagram of a phase change controller according to an embodiment of the present application is shown. Reference is made to this figure and to the accompanying Figure 2 The structure of the phase change controller 13 is described in detail. The phase change controller 13 mainly comprises a high-pressure resistant container 13a capable of bearing a pressure greater than 15 MPa and a first temperature control mechanism 13b. The high-pressure resistant container 13a is in a hollow tubular structure and has a space inside for containing carbon dioxide. The first temperature control mechanism 13b comprises an outer shell forming a temperature control chamber for containing the high-pressure resistant container 13a, a resistance heating component adjacent to the high-pressure resistant container, and a refrigerant pipeline for introducing a refrigerant, which can be liquid nitrogen, into the temperature control chamber. The resistance heating component can comprise a plurality of resistance heating elements uniformly distributed around the circumference of the high-pressure resistant container. The first temperature control mechanism 13b is used to control and adjust the temperature in the high-pressure resistant container 13a. A transparent window can also be provided on the high-pressure resistant container 13a to facilitate observation of the phase state of the CO2 in the high-pressure resistant container 13a.

[0058] A plurality of detected positions can be selected according to the size of the high-pressure resistant container 13a, and the distance between adjacent detected positions can be controlled to be 0.3-0.5 meters. Since the distances between different positions in the high-pressure resistant container 13a and the heating component are different, there is a temperature gradient change in different positions in the high-pressure resistant container 13a, which is monitored by installing temperature sensors at different positions. As shown in the figure, the high-pressure resistant 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 sensors ST1 and the pressure sensor SP1 are sent to the data processing device 14. The working temperature range of the phase change controller 13 is -50℃-100℃, and the working pressure range is 0.01 MPa-12 MPa. During testing, the temperature gradient is set by using the temperature adjustment function of the temperature control mechanism 13b, the temperature is dynamically adjusted at a selected fixed pressure, the temperature and phase change at different positions are observed, and relevant data are collected.

[0059] Figure 4 A structural schematic diagram of a high-pressure loop system 10 according to an embodiment of the present application is shown. Reference is made to this figure and to the accompanying Figure 2The high-pressure loop system 10 is described in detail. The high-pressure loop system 10 generally comprises a high-pressure resistant pipe 9 and a second temperature control mechanism. The high-pressure resistant pipe 9 is a pipe with a certain length, and the high-pressure resistant pipe 9 can withstand a pressure greater than 15 MPa. The second temperature control mechanism comprises a water circulating machine 12 and a circulating jacket 11 wrapped outside the high-pressure resistant pipe 9. The circulating jacket 11 is provided with a water circulating pipeline in communication with the water circulating machine 12, and the water circulating machine 12 can adjust and control the temperature of the water in the water circulating pipeline, thereby adjusting the temperature in the high-pressure resistant pipe 9. The working temperature range of the high-pressure loop system 10 is 0-80℃, and the working pressure range is 0.01-12 MPa.

[0060] A plurality of measured positions are selected on the high-pressure resistant pipe 9 to arrange pressure sensors 6 and temperature sensors 7 to detect the temperature, pressure and phase state at different positions along the pipe axis. For this purpose, a corresponding transparent window is also arranged at each measured position to visualize the phase state of CO2 at the measured position of the high-pressure resistant pipe 9. The number of measured positions can be determined according to the length of the high-pressure resistant pipe 9, and the distance between adjacent measured positions is 1-3 meters. The data collected by the pressure sensors 6 and the temperature sensors 7 are sent to a data processing device 14.

[0061] The data processing device 14 generates a phase transition 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 transition 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 application also provides a method for dynamically monitoring the CO2 phase state conversion of the conveying pipeline by using the above system, which comprises the following steps:

[0063] Step S1, CO2 is introduced into the high-pressure loop system, the pressure at each measured position is monitored, and a predetermined pressure gradient of the whole pipeline is realized by setting the pressure;

[0064] Step S2, pressure response tests are carried out at a plurality of different temperatures by using the high-pressure loop system, at each test temperature, the pressure of CO2 in the high-pressure loop system is dynamically adjusted, and the pressure at each measured position is monitored;

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

[0066] Step S4, CO2 is introduced into the phase transition controller, the temperature of the phase transition controller is adjusted, the temperature at each measured position is monitored, and a predetermined temperature gradient distribution in the container is realized;

[0067] Step S5, temperature response test is carried out respectively by using the phase change controller for multiple different pressures, at each test pressure, the temperature in the phase change controller is dynamically adjusted, and the temperature of each measured position is monitored;

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

[0069] The following will be described in detail.

[0070] In step S1, the method of realizing the pressure gradient of the whole pipeline is: using the principle that the high-pressure ring channel has pressure drop, and the pressure drop increases with the increase of CO2 injection flow, by setting the inlet pressure, inlet flow and pipeline length to realize the predetermined pressure gradient. Because the high-pressure ring channel has pressure drop, and the pressure drop increases with the increase of injection flow, therefore, the supercritical / liquid CO2 in the pipeline will expand and gasify after passing through the whole pipeline below the critical pressure / gas-liquid equilibrium pressure.

[0071] In step S2, the temperature, inlet pressure and inlet flow of the high-pressure ring channel need to be coordinated 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, at each test temperature, the pressure of CO2 in the high-pressure ring channel system is dynamically adjusted by changing the inlet pressure and inlet flow of the high-pressure ring channel, and the pressure and phase state of each measured position are monitored. When setting the temperature, inlet pressure and inlet flow of the high-pressure ring channel, it is necessary to ensure that the pipeline can appear supercritical state, supercritical state to gas state, gas state, or liquid state, liquid state to gas state, gas state, and the gas-liquid equilibrium pressure at the set temperature should be between the pipeline inlet pressure and the pipeline end pressure. For each test temperature, such pressure dynamic adjustment is carried out, and the temperature and pressure information of each position is collected. By 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 is sorted to obtain the pressure response model at each measured position. The sensor output data includes corresponding pressure or temperature, time and other information, and the position information of the sensor can be determined according to the number of the sensor. Based on the pressure information measured by the pressure sensor and the temperature information measured by the temperature sensor at each measured position, the density of CO2 at the measured position is fitted by using the state equation, which is combined with the position and time to draw a three-dimensional graph to represent the pressure response model of the phase change. Based on the graph, the phase state of CO2 at different positions and different times in the pipeline, and the influence of pressure gradient on the phase state can be clearly and intuitively judged.

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

[0074] In step S5, the temperature response test is performed for a plurality of different pressures respectively by using the phase change controller, and in each test pressure, the temperature in the phase change controller is dynamically adjusted, and the temperature and phase state of each measured position are monitored. That is, a plurality of different pressures can be selected for the temperature response test respectively, and in each test period, the pressure is fixed and remains unchanged. Since the temperature of the measured point in the phase change controller can be adjusted, the corresponding gas-liquid equilibrium temperature is taken as the test starting temperature, the temperature in the phase change controller is gradually reduced to observe the compression liquefaction of liquid CO2 and collect pressure and temperature data, or the corresponding gas-liquid equilibrium temperature is taken as the lowest temperature, and the temperature in the phase change controller is gradually increased to observe the expansion vaporization of liquid CO2 and collect pressure and temperature data. Then, the set pressure is changed, and the temperature is dynamically adjusted again and the related data are collected. After the data are sorted and processed, the phase change with the temperature gradient can be obtained, and a phase change model can be obtained. Similarly to step S3, the sensor output data include corresponding pressure or temperature, time, etc. information, and the position information of the sensor can be determined according to the number of the sensor. Based on the pressure information measured by the pressure sensor and the temperature information measured by each temperature sensor, the density of CO2 at the measured position is fitted by using a state equation, and is combined with the position and time to draw a three-dimensional graph to represent the temperature response model of the phase change. Based on the graph, the phase state of CO2 at different positions and different times in the pipeline and the influence of the temperature gradient on the phase state can be clearly and intuitively judged.

[0075] The system and method of the present application not only can be used for dynamically monitoring the phase state conversion of pure CO2, but also can be used for dynamically monitoring the phase state conversion of CO2 containing impurities. When the phase state conversion of CO2 containing impurities is dynamically monitored, only the component of the gas provided to the pressure control system needs to contain a predetermined amount of impurities. The system and method of the present application can be used to observe the conversion between different phase states of CO2 very comprehensively.

[0076] The preferred embodiments of the present application are described in detail above, but the present application is not limited to the specific details in the above-described embodiments, and various simple modifications can be made to the technical solutions of the present application within the technical concept of the present application, and these simple modifications all belong to the protection scope of the present application.

[0077] It should be further noted that each of the various technical features described in the above embodiments can be combined with any other technical features in any suitable manner, and the present application is not limited to the combinations explicitly described herein, unless otherwise specified.

[0078] Furthermore, any combination of the various embodiments of the present application can be made, as long as it does not deviate from the spirit of the present application, and it should be considered as disclosed by the present application.

Claims

1. A dynamic monitoring system for CO2 phase transformation suitable for CO2 transportation pipelines, characterized in that, include: Gas supply system; A pressure control system that receives CO2 gas from the gas supply system and regulates the pressure of the CO2 gas; A phase change controller receives CO2 gas from the pressure control system and provides a preset temperature gradient for the CO2 gas; A high-pressure loop system, wherein the high-pressure loop system receives CO2 gas from the pressure control system and provides a preset pressure gradient for the CO2 gas; The measuring device includes a plurality of first temperature sensors and at least one first pressure sensor disposed at different locations in the phase change controller, and a plurality of second temperature sensors and a plurality of second pressure sensors disposed at different locations in 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 phase change pressure response models at different locations at different temperatures based on the data from the first temperature sensor and the first pressure sensor, and generates phase change temperature response models at different locations under 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 cylinder, a gas pressure reducing valve, and connecting pipelines.

3. The system according to claim 1, characterized in that, The pressure control system includes a booster pump, a high-pressure 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 installed in two parallel branches downstream of the autoclave, and each branch is equipped with a flow meter.

5. The system according to claim 4, characterized in that, The phase change controller includes a high-pressure resistant container, a first temperature control mechanism, a plurality of first temperature sensors disposed at different locations inside the high-pressure resistant container, and at least one first pressure sensor disposed inside the high-pressure resistant container.

6. The system according to claim 5, characterized in that, The first temperature control mechanism includes an outer shell forming a temperature control chamber for housing the high-pressure container, a resistance heating element 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 resistant vessel includes a transparent viewing window.

8. The system according to claim 4, characterized in that, The high-pressure loop system includes a high-pressure resistant tube and a second temperature control mechanism, with multiple second temperature sensors and multiple second pressure sensors disposed at different axial measurement positions of the high-pressure resistant tube.

9. The system according to claim 8, characterized in that, The number of the second temperature sensor and the second pressure sensor are the same, and one second temperature sensor and one second pressure sensor are set at each measured location.

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

11. The system according to claim 8, characterized in that, The second temperature control mechanism includes a water circulator and a circulation jacket. The circulation jacket is wrapped around the outside of the high-pressure resistant pipe. A water circulation pipeline is provided inside the circulation jacket. The water circulation pipeline is connected to the water circulator. The water circulator 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 a transparent window, which is located at the test position and the number of transparent windows is the same as the number of test 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 waste gas tank by two parallel exhaust branches, and each of the parallel exhaust branches is equipped with a control valve.

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

15. The system according to claim 1, characterized in that, The phase change controller operates in a temperature range of -50℃ to 100℃ and in a pressure range of 0.01MPa to 12MPa.

16. A method for dynamically monitoring the phase transition of CO2 in a transport pipeline using the system as described in any one of claims 1-15, characterized in that, Includes the following steps: Step S1: Introduce CO2 into the high-pressure loop system, monitor the pressure at each measured location, and achieve the predetermined pressure gradient of the entire pipeline by setting the pressure. Step S2: Perform pressure response tests on the high-pressure loop system for multiple different temperatures. At each test temperature, dynamically adjust the CO2 pressure in the high-pressure loop system and monitor the pressure at each test location. Step S3: Organize the phase change pressure response data at different temperatures in step S2 to obtain the pressure response model at each measured location; Step S4: Introduce CO2 into the phase change controller, adjust the temperature of the phase change controller, monitor the temperature at each measured location, and achieve a predetermined temperature gradient distribution within the container. Step S5: Perform temperature response tests on multiple different pressures using the phase change controller. At each test pressure, dynamically adjust the temperature inside the phase change controller and monitor the temperature at each test location. Step S6: Organize the phase change temperature response data under different pressures in step S5 to obtain the temperature response model at each measured location.

17. The method according to claim 16, characterized in that, In step S1, the method to achieve the pressure gradient of the entire pipeline is to utilize the principle that there is a pressure drop in the high-pressure loop and that the pressure drop increases with the increase of CO2 injection flow rate, and to achieve 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 set in a coordinated manner to ensure that the gas-liquid balance pressure at the set temperature is between the inlet pressure and the end pressure of the pipe.

19. The method according to claim 16, characterized in that, In step S4, the method to achieve the predetermined temperature gradient distribution inside 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.

20. The method according to claim 16, characterized in that, In step S5, the dynamic adjustment of the temperature inside the phase change controller at each test pressure includes: maintaining the pressure inside the phase change controller at the selected test pressure, setting the corresponding gas-liquid equilibrium temperature as the highest temperature, gradually decreasing the temperature inside the phase change controller, and observing the compression and liquefaction of liquid CO2; or setting the corresponding gas-liquid equilibrium temperature as the lowest temperature, gradually increasing the temperature inside the phase change controller, and observing the expansion and vaporization of liquid CO2.

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