Carbon dioxide near-critical point dynamic physical property test platform and test method

Abstract

The invention belongs to the technical field of carbon dioxide phase change fracturing rocks, and provides a carbon dioxide near-critical point dynamic physical property testing platform and a testing method. The carbon dioxide flow control assembly comprises a temperature regulator and an electromagnetic flowmeter which are communicated in sequence, and the carbon dioxide pressurizing and filling assembly is communicated with the temperature regulator; the air inlet end of the experiment pipeline is communicated with the electromagnetic flowmeter through an electromagnetic valve, the air outlet end of the experiment pipeline is communicated with a discharge tank, and heating pieces are arranged in the experiment pipeline and the discharge tank respectively; the gas circulating system comprises a gas circulating pump, the gas inlet end of the gas circulating pump is communicated with the discharge tank, and the gas outlet end of the gas circulating pump is communicated with the carbon dioxide pressurizing and filling assembly; and the data acquisition system comprises a differential pressure sensor, a plurality of pressure sensors and a plurality of temperature sensors. The device can be used for testing the change of physical property parameters such as pressure, temperature, density, viscosity and specific heat capacity ratio of the near-critical point of carbon dioxide.

Description

Technical Field

[0001] The present invention belongs to the technical field of carbon dioxide phase change fracturing of rocks, and particularly relates to a carbon dioxide near-critical point dynamic physical property testing platform and a testing method. Background Art

[0002] In recent years, carbon dioxide has been widely used in many fields, such as stimulation of unconventional reservoirs, hydraulic engineering, urban infrastructure construction, etc. In these applications, dynamic monitoring of the physical property parameters of near-critical point carbon dioxide is of great significance for guiding related technologies and research.

[0003] In the field of stimulation of unconventional reservoirs, carbon dioxide can form a miscible phase with reservoir oil and gas, thereby reducing the viscosity of oil and gas, improving fluidity, and then increasing the recovery rate. In this process, carbon dioxide phase change fracturing is an important mechanism, and the change of physical property parameters near the critical point of carbon dioxide will affect its phase change process. In the carbon dioxide fracturing process, the injected liquid carbon dioxide will undergo a phase change into a gas state in the formation, generating a fracturing effect. Understanding the change of physical property parameters near the critical point of carbon dioxide helps to optimize the fracturing design and improve the fracturing effect.

[0004] However, at present, there is little research on the change of carbon dioxide physical property parameters along the way, and there is a lack of systematic experimental data and theoretical models. Studying the change of physical property parameters near the critical point of carbon dioxide mainly relies on experimental measurement. Due to special pressure and temperature conditions, higher requirements are put forward for the accuracy and reliability of measurement equipment. Existing carbon dioxide physical property testing methods and devices have certain limitations and cannot be better applied to the testing of dynamic changes of carbon dioxide physical property parameters along the way. Therefore, there is an urgent need for a carbon dioxide near-critical point dynamic physical property testing platform and a testing method that can measure parameters such as temperature, pressure, density, viscosity, and specific heat ratio, so as to help deeply reveal the change law of physical property parameters near the critical point of carbon dioxide, and thus provide important experimental data support for application research in related fields. Summary of the Invention

[0005] The purpose of the present invention is to provide a carbon dioxide near-critical point dynamic physical property testing platform and a testing method to solve the above problems and achieve the purpose of testing the changes of physical property parameters such as pressure, temperature, density, viscosity, and specific heat ratio of carbon dioxide inside the experimental pipeline of carbon dioxide.

[0006] To achieve the above purpose, the present invention provides the following solution: A carbon dioxide near-critical point dynamic physical property testing platform, comprising:

[0007] A carbon dioxide pressurization and filling assembly;

[0008] A carbon dioxide flow control assembly, comprising a temperature regulator and an electromagnetic flowmeter connected in sequence. The carbon dioxide pressurization and filling assembly inputs carbon dioxide into the temperature regulator, and the electromagnetic flowmeter is used to measure the amount of carbon dioxide passing through;

[0009] An experimental pipeline, the intake end of the experimental pipeline is connected to the outlet end of the electromagnetic flowmeter through a solenoid valve, the outlet end of the experimental pipeline is connected to a discharge tank through a first connecting pipe, and heating elements are respectively arranged in the experimental pipeline and the discharge tank;

[0010] A gas circulation system, comprising a gas circulation pump. The intake end of the gas circulation pump is connected to the discharge tank through a second connecting pipe, and the outlet end of the gas circulation pump is connected to the carbon dioxide pressurization and filling assembly;

[0011] A data acquisition system, comprising a differential pressure sensor arranged between the intake end and the outlet end of the experimental pipeline, and a plurality of pressure sensors and temperature sensors arranged in the experimental pipeline and the discharge tank.

[0012] Preferably, the carbon dioxide pressurization and filling assembly includes a gas storage tank. The outlet of the gas storage tank is connected to a booster pump through a circulation tank. The outlet end of the booster pump is connected to the temperature regulator. The booster pump is used to pressurize carbon dioxide gas and transport it into the temperature regulator, and the outlet end of the gas circulation pump is connected to the circulation tank.

[0013] Preferably, a buffer tank is connected between the booster pump and the temperature regulator. The buffer tank is used to make the flow rate, temperature, and pressure of the carbon dioxide entering the temperature regulator tend to be stable.

[0014] Preferably, the heating element includes a heating tube. The heating tubes are respectively arranged in the experimental pipeline and the discharge tank, and the heating tube in the experimental pipeline is located at one end of the experimental pipeline.

[0015] Preferably, two groups of sensor mounting parts are provided on the side wall of the experimental pipeline. The two groups of sensor mounting parts are symmetrically arranged about the axis of the experimental pipeline. The sensor mounting part includes a plurality of mounting holes opened on the side wall of the experimental pipeline. The plurality of mounting holes are equidistantly distributed along the axis of the experimental pipeline. A plurality of the mounting holes on one side of the axis of the experimental pipeline are used to mount a plurality of the pressure sensors, and a plurality of the mounting holes on the other side of the axis of the experimental pipeline are used to mount a plurality of the temperature sensors;

[0016] Second mounting holes are respectively opened at both ends of the side wall of the experimental pipeline, and the two groups of second mounting holes are used to connect the differential pressure sensor.

[0017] Preferably, a pressure sensor and a temperature sensor are also connected between the electromagnetic flowmeter and the experimental pipeline.

[0018] Preferably, a cooling system is further included. The inlet end and the outlet end of the cooling system are respectively connected to the second pipeline through a third connecting pipe and a fourth connecting pipe. A fifth connecting pipe is connected between one end of the first connecting pipe and the second connecting pipe close to the relief tank. A first valve is connected to the first connecting pipe and is arranged close to the relief tank. A second valve and a third valve are respectively connected to the fifth connecting pipe and the third connecting pipe. A fourth valve is connected to the second connecting pipe and is located between the third connecting pipe and the fourth connecting pipe.

[0019] A method for testing the dynamic physical properties of carbon dioxide near the critical point, the operation steps include:

[0020] Install a number of pressure sensors, temperature sensors and differential pressure sensors on the experimental pipeline and detect the airtightness of the test platform;

[0021] Empty the air in the experimental pipeline and the relief tank, and fill the liquid carbon dioxide into the experimental pipeline through the temperature regulator and the electromagnetic flowmeter by means of the carbon dioxide booster filling assembly;

[0022] Start the heating element, heat the carbon dioxide in the experimental pipeline to the critical state, and record the measured values of each sensor for calculating the physical property parameters of carbon dioxide at the critical point in the experimental pipeline.

[0023] Compared with the prior art, the present invention has the following advantages and technical effects:

[0024] 1. The test platform of the present invention can effectively test the changes in temperature and pressure at the near-critical point of carbon dioxide at the same time, and the obtained data is beneficial to analyzing the changes in various physical property parameters along the experimental pipeline.

[0025] 2. The test platform of the present invention can obtain the changes in viscosity and density at different positions in the pipeline according to the detected temperature and pressure changes in the experimental pipeline.

[0026] 3. The test platform of the present invention can measure the specific heat ratio of carbon dioxide by the adiabatic expansion method by connecting a relief tank to the outlet end of the experimental pipeline. Description of the Drawings

[0027] In order to more clearly illustrate the technical solutions in the embodiments of the present invention or the prior art, the following will briefly introduce the drawings required in the embodiments. Obviously, the drawings in the following description are only some embodiments of the present invention. For those of ordinary skill in the art, other drawings can be obtained based on these drawings without creative efforts.

[0028] Figure 1 Schematic diagram of the connections between components of the test platform of the present invention;

[0029] Among them, 1, gas storage tank; 2, circulation tank; 3, booster pump; 4, buffer tank; 5, temperature regulator; 6, electromagnetic flowmeter; 7, heating tube; 8, relief tank; 9, cooling system; 10, gas circulation pump; 11, heating core temperature control box; 12, flow central control system; 13, data display terminal; 14, data acquisition instrument; 15-1, first valve; 15-2, second valve; 15-3, third valve; 15-4, fourth valve; 16, signal cable; 17, experimental pipeline; 18, gas circulation pump controller; 19, pressure sensor; 20, temperature sensor; 21, differential pressure sensor; 22, first connecting pipe; 23, second connecting pipe; 24, third connecting pipe; 25, fourth connecting pipe; 26, fifth connecting pipe. Specific embodiments

[0030] Next, the technical solutions in the embodiments of the present invention will be clearly and completely described in conjunction with the accompanying drawings in the embodiments of the present invention. Obviously, the described embodiments are only a part of the embodiments of the present invention, rather than all the embodiments. Based on the embodiments of the present invention, all other embodiments obtained by those of ordinary skill in the art without creative efforts shall fall within the protection scope of the present invention.

[0031] To make the above objects, features, and advantages of the present invention more obvious and understandable, the present invention will be further described in detail below in conjunction with the accompanying drawings and specific embodiments.

[0032] Embodiment 1:

[0033] Referring to Figure 1 , the present invention provides a carbon dioxide near-critical point dynamic physical property test platform, including:

[0034] Carbon dioxide pressurization and filling assembly;

[0035] Carbon dioxide flow control assembly, including a temperature regulator 5 and an electromagnetic flowmeter 6 connected in sequence. The carbon dioxide pressurization and filling assembly inputs carbon dioxide into the temperature regulator 5, and the electromagnetic flowmeter 6 is used to measure the amount of carbon dioxide passing through;

[0036] Experimental pipeline 17, the inlet end of the experimental pipeline 17 is connected to the outlet end of the electromagnetic flowmeter 6 through a solenoid valve, the outlet end of the experimental pipeline 17 is connected to a relief tank 8 through a first connecting pipe 22, and heating elements are respectively arranged in the experimental pipeline 17 and the relief tank 8;

[0037] Gas circulation system, including a gas circulation pump 10, the intake end of the gas circulation pump 10 is communicated with the relief tank 8 through a second connecting pipe 23, and the outlet end of the gas circulation pump 10 is communicated with a carbon dioxide boosting and filling assembly;

[0038] Data acquisition system, including a differential pressure sensor 21 arranged between the intake end and the outlet end of the experimental pipeline 17, and a number of pressure sensors 19 and temperature sensors 20 arranged in the experimental pipeline 17 and the relief tank 8.

[0039] The main function of the carbon dioxide boosting and filling assembly is to deliver the boosted carbon dioxide gas to the temperature regulator 5; the main function of the temperature regulator 5 is to keep the carbon dioxide at a constant pressure and temperature; the main function of the electromagnetic flowmeter 6 is to measure the flow rate of the passing carbon dioxide, so that the required mass of carbon dioxide enters the experimental pipeline 17; the main function of the heating element is to heat the carbon dioxide in the experimental pipeline 17 to reach the critical state; the main function of the gas circulation pump 10 is to enable the carbon dioxide after the test to circulate among the components. Overall, the present invention can effectively test the changes in temperature and pressure of carbon dioxide near the critical point at the same time, and obtain the changes in viscosity and density at different positions in the pipeline according to the detected temperature and pressure changes in the experimental pipeline; at the same time, by connecting a relief tank at the outlet end of the experimental pipeline, the specific heat ratio of carbon dioxide can be measured by the adiabatic expansion method.

[0040] In a further optimized scheme, the gas circulation pump 10 is also electrically connected to a gas circulation pump controller 18.

[0041] In a further optimized scheme, the carbon dioxide boosting and filling assembly includes a gas storage tank 1, the outlet of the gas storage tank 1 is communicated with a boosting pump 3 through a circulation tank 2, the outlet end of the boosting pump 3 is communicated with the temperature regulator 5, and the boosting pump 3 is used to boost the carbon dioxide gas and deliver it to the temperature regulator 5, and the outlet end of the gas circulation pump 10 is communicated with the circulation tank 2.

[0042] The main function of the gas storage tank 1 is to store the carbon dioxide gas source, with a storage temperature of -20°C and a storage pressure of 2.2 MPa, and it can discharge liquid carbon dioxide with a pressure of 2 MPa. The boosting pump 3 can increase the liquid carbon dioxide from 2 MPa to 7 - 12 MPa and deliver it in the direction of the temperature regulator 5.

[0043] In a further optimized scheme, a buffer tank 4 is communicated between the boosting pump 3 and the temperature regulator 5, and the buffer tank 4 is used to make the flow rate, temperature, and pressure of the carbon dioxide entering the temperature regulator 5 tend to be stable.

[0044] In a further optimized scheme, the boosting pump 3, the buffer tank 4, the temperature regulator 5, and the electromagnetic flowmeter 6 are respectively electrically connected to a flow central control system 12.

[0045] Further optimized solution: The heating element includes a heating tube 7. Heating tubes 7 are respectively arranged in the experimental pipeline 17 and the drain tank 8. The heating tube 7 in the experimental pipeline 17 is located at one end of the experimental pipeline 17.

[0046] Further optimized solution: Two groups of heating tubes 7 are respectively electrically connected to a heating core temperature control box 11.

[0047] Further optimized solution: Two groups of sensor mounting parts are provided on the side wall of the experimental pipeline 17. The two groups of sensor mounting parts are symmetrically arranged with respect to the axis of the experimental pipeline 17. The sensor mounting part includes a number of mounting holes opened on the side wall of the experimental pipeline 17. The number of mounting holes are equally spaced along the axis of the experimental pipeline 17. A number of mounting holes on one side of the axis of the experimental pipeline 17 are used to mount a number of pressure sensors 19, and a number of mounting holes on the other side of the axis of the experimental pipeline 17 are used to mount a number of temperature sensors 20;

[0048] Second mounting holes are respectively opened at both ends of the side wall of the experimental pipeline 17. The two groups of second mounting holes are used to connect a differential pressure sensor 21.

[0049] The pressure sensor 19 uses a piezoelectric pressure sensor. As Figure 1 shown, through a number of first mounting holes, a number of pressure sensors 19 are fixedly connected to one side of the experimental pipeline 17, and a number of temperature sensors 20 are fixedly connected to the other side of the experimental pipeline 17.

[0050] During the experiment, after the experimental pipeline 17 is fixed to a bracket (not shown in the figure), all the pressure sensors 19 are on the same horizontal line, and all the temperature sensors 20 are also on the same horizontal line.

[0051] The positions of a number of pressure sensors 19 and temperature sensors 20 installed on the experimental pipeline 17 and the drain tank 8 need to ensure that the carbon dioxide therein can immerse the contact rod of the temperature sensor and the contact hole of the pressure sensor.

[0052] Further optimized solution: A pressure sensor 19 and a temperature sensor 20 are also connected between the electromagnetic flowmeter 6 and the experimental pipeline 17.

[0053] Further optimized solution: The differential pressure sensor 21, a number of pressure sensors 19 and a number of temperature sensors 20 are respectively electrically connected to a data acquisition instrument 14, and the data acquisition instrument 14 is electrically connected to a data display terminal 13.

[0054] Further optimized solution: As Figure 1As shown, a plurality of temperature sensors 20 on the experimental pipeline 17 and a plurality of pressure sensors 19 on the experimental pipeline 17 are electrically connected through signal cables 16 respectively, and the data acquisition instrument 14 realizes electrical connection with a plurality of pressure sensors 19 and temperature sensors 20 through two groups of signal cables 16.

[0055] The further optimized solution further includes a cooling system 9. The inlet end and the outlet end of the cooling system 9 are respectively communicated with the second connecting pipe 23 through a third connecting pipe 24 and a fourth connecting pipe 25. A fifth connecting pipe 26 is communicated between one end of the first connecting pipe 22 and the second connecting pipe 23 close to the relief tank 8. A first valve 15-1 is communicated on the first connecting pipe 22, and the first valve 15-1 is arranged close to the relief tank 8. A second valve 15-2 and a third valve 15-3 are respectively communicated on the fifth connecting pipe 26 and the third connecting pipe 24. A fourth valve 15-4 is communicated on the second connecting pipe 23, and the fourth valve 15-4 is located between the third connecting pipe 24 and the fourth connecting pipe 25.

[0056] A method for testing the dynamic physical properties of carbon dioxide near the critical point, the operation steps include:

[0057] Install a plurality of pressure sensors 19, temperature sensors 20 and differential pressure sensors 21 on the experimental pipeline 17, and detect the air tightness of the test platform;

[0058] Empty the air in the experimental pipeline 17 and the relief tank 8, and fill the liquid carbon dioxide into the experimental pipeline 17 through the temperature regulator 5 and the electromagnetic flowmeter 6 by means of the carbon dioxide pressurization and filling assembly;

[0059] Start the heating element, heat the carbon dioxide in the experimental pipeline 17 to the critical state, and record the measured values of each sensor for calculating the physical property parameters of the carbon dioxide near the critical point in the experimental pipeline 17.

[0060] Embodiment 2:

[0061] According to the method for testing the dynamic physical properties of carbon dioxide near the critical point in Embodiment 1, the method for measuring the density of carbon dioxide includes:

[0062] The liquid carbon dioxide gas in the gas storage tank 1 is pressurized by the booster pump 3 and then enters the temperature regulator 5 to ensure that the experimental gas is at a constant pressure and temperature. After pressurization and temperature increase, the required mass of carbon dioxide at the predicted temperature and pressure enters the experimental pipeline 17. After reaching the experimental pressure, the solenoid valve between the electromagnetic flowmeter 6 and the experimental pipeline 17 is closed. The heating tube 7 is used to change the temperature of the carbon dioxide in the experimental pipeline 17 to make it reach the critical state. At this time, the temperature, pressure and differential pressure of the differential pressure sensor in the test section of the experimental pipeline 17 are dynamically recorded. After the recording is completed, the first valve 15-1, the third valve 15-3 are opened and the gas circulation pump 10 is started. The experimental gas flows out from the test section of the experimental pipeline 17 and enters the cooling system 9 for cooling. The cooled experimental gas is pressurized and circulated by the gas circulation pump 10 and enters the circulation tank 2 for the next experiment. During the experiment, the readings of various meters in the test section of the experimental pipeline 17 during the flow process, including pressure, temperature, differential pressure, etc., are collected and recorded in real time through the data display terminal 13.

[0063] First, the density of pure water is used to calibrate the differential pressure to obtain the density and differential pressure at known temperature and pressure. The carbon dioxide in the pipeline is measured in the same way, and finally the density of carbon dioxide is calculated.

[0064] Example 3:

[0065] According to the method for dynamically measuring the physical properties of carbon dioxide near the critical point in Example 1, the method for carbon dioxide includes:

[0066] The liquid carbon dioxide gas in the gas storage tank 1 is pressurized by the booster pump 3 and then enters the temperature regulator 5 to ensure that the experimental gas is at a constant pressure and temperature. After pressurization and temperature increase, the required mass of carbon dioxide at the predicted temperature and pressure enters the experimental pipeline 17. After reaching the experimental pressure, the solenoid valve between the electromagnetic flowmeter 6 and the experimental pipeline 17 is closed. The heating tube 7 is used to change the temperature of the carbon dioxide in the experimental pipeline 17 to make it reach the critical state. After that, the first valve 15-1, the second valve 15-2 and the fourth valve 15-4 are opened, and the gas circulation pump 10 is started to form a closed system of the circulation tank 2, the booster pump 3, the buffer tank 4, the temperature regulator 5, the electromagnetic flowmeter 6, the experimental pipeline 17, and the gas circulation pump 10, and the gas circulation pump 10 provides the required power.

[0067] According to the density measured at different temperatures and pressures under the experimental conditions and the differential pressure of the measurement section, the temperature T, pressure P, flow velocity v, length L of the flowing section, and inner diameter d are recorded during the experiment. Finally, the viscosity of carbon dioxide is calculated.

[0068] Example 4:

[0069] According to the carbon dioxide near-critical point dynamic physical property testing method of Embodiment 1, the method for measuring the specific heat ratio of carbon dioxide in the experimental pipeline 17 includes:

[0070] The liquid carbon dioxide gas in the gas storage tank 1 is pressurized by the booster pump 3 and then enters the temperature regulator 5 to ensure that the experimental gas is at a constant pressure and temperature. After pressurization and temperature increase, the required mass of carbon dioxide at the predicted temperature and pressure enters the experimental pipeline 17. After reaching the experimental pressure, the solenoid valve between the electromagnetic flowmeter 6 and the experimental pipeline 17 is closed. The carbon dioxide in the experimental pipeline 17 is heated by the heating tube 7 to reach the temperature and pressure to be measured, and the gas in the drain tank 8 is drained. The temperature in the drain tank 8 is heated to be the same as the temperature in the experimental pipeline 17. After the pressure is stable, the current temperature T0 and pressure P1 are recorded. Then, the first valve 15-1 is suddenly opened, and the pressure in the experimental pipeline 17 will rapidly decrease. At the same time, the temperature and pressure changes in the drain tank 8 are monitored. This process needs to be rapid and is considered adiabatic. When the pressure in the experimental pipeline 17 is the same as the pressure in the drain tank 8, the first valve 15-1 is closed, and the pressure P0 and temperature T1 of this process are recorded. The temperature in the experimental pipeline 17 is raised to T0 again by the heating tube 7, and the pressure change P2 in the pipeline is recorded. Finally, based on the obtained parameters, the specific heat ratio in the pipeline is calculated.

[0071] Embodiment 5:

[0072] According to the carbon dioxide near-critical point dynamic physical property testing method of Embodiment 1, the testing methods for the specific heat at constant volume and the specific heat at constant pressure include:

[0073] The liquid carbon dioxide gas in the gas storage tank 1 is pressurized by the booster pump 3 and then enters the temperature regulator 5 to ensure that the experimental gas is at a constant pressure and temperature. After pressurization and temperature increase, the required mass of carbon dioxide at the predicted temperature and pressure enters the experimental pipeline 17. After reaching the experimental pressure, the solenoid valve between the electromagnetic flowmeter 6 and the experimental pipeline 17 is closed. The temperature of the carbon dioxide in the experimental pipeline 17 is changed by the heating tube 7 to reach the critical state, and the current pressure P0 and temperature T0 are recorded. Then, heating is carried out by the heating tube 7, and the heating quantity is recorded as Q. After the pressure and temperature in the experimental pipeline 17 are stable, the temperature T1 in the pipeline is recorded. Finally, based on the obtained parameters, the specific heat at constant pressure and the specific heat at constant volume are calculated.

[0074] In the description of the present invention, it should be understood that the orientation or positional relationship indicated by the terms "longitudinal", "transverse", "upper", "lower", "front", "rear", "left", "right", "vertical", "horizontal", "top", "bottom", "inner", "outer", etc. is based on the orientation or positional relationship shown in the drawings, and is only for the convenience of describing the present invention, rather than indicating or implying that the device or element referred to must have a specific orientation, be constructed and operated in a specific orientation, and therefore should not be construed as a limitation to the present invention.

[0075] The embodiments described above are only descriptions of the preferred embodiments of the present invention, and do not limit the scope of the present invention. Without departing from the design spirit of the present invention, various deformations and improvements made by those of ordinary skill in the art to the technical solutions of the present invention shall fall within the protection scope determined by the claims of the present invention.

Claims

1. A carbon dioxide near critical point dynamic physical property testing platform, characterized in that: include: Carbon dioxide pressurized filling components; A carbon dioxide flow control component comprises a temperature regulator (5) and an electromagnetic flow meter (6) which are connected in sequence, wherein the carbon dioxide pressurizing and filling component inputs carbon dioxide into the temperature regulator (5), and the electromagnetic flow meter (6) is used to measure the amount of carbon dioxide passing through; An experimental pipeline (17), wherein an air inlet end of the experimental pipeline (17) is connected to an air outlet end of the electromagnetic flowmeter (6) via an electromagnetic valve, and an air outlet end of the experimental pipeline (17) is connected to a discharge tank (8) via a first connecting pipe (22), and a heating element is respectively provided in the experimental pipeline (17) and the discharge tank (8); A gas circulation system, comprising a gas circulation pump (10), wherein an air inlet end of the gas circulation pump (10) is connected to the discharge tank (8) via a second connecting pipe (23), and an air outlet end of the gas circulation pump (10) is connected to the carbon dioxide pressurizing and filling assembly; The data acquisition system comprises a differential pressure sensor (21) arranged between the air inlet and the air outlet of the experimental pipeline (17) and a plurality of pressure sensors (19) and temperature sensors (20) arranged in the experimental pipeline (17) and the discharge tank (8).

2. A carbon dioxide near critical point dynamic physical property testing platform according to claim 1, characterized in that: The carbon dioxide pressurized filling assembly comprises a gas storage tank (1), the gas outlet of the gas storage tank (1) is connected to a booster pump (3) through a circulation tank (2), the gas outlet end of the booster pump (3) is connected to the temperature regulator (5), the booster pump (3) is used to pressurize the carbon dioxide gas and then transport it to the temperature regulator (5), and the gas outlet end of the gas circulation pump (10) is connected to the circulation tank (2).

3. A carbon dioxide near critical point dynamic physical property testing platform according to claim 2, characterized in that: A buffer tank (4) is connected between the booster pump (3) and the temperature regulator (5), and the buffer tank (4) is used to stabilize the flow rate, temperature and pressure of the carbon dioxide entering the temperature regulator (5).

4. A carbon dioxide near-critical point dynamic physical property testing platform according to claim 1, characterized in that: The heating element comprises a heating pipe (7), the heating pipe (7) being arranged in the experimental pipeline (17) and the discharge tank (8) respectively, and the heating pipe (7) in the experimental pipeline (17) is located at one end of the experimental pipeline (17).

5. A carbon dioxide near-critical point dynamic physical property testing platform according to claim 1, characterized in that: Two groups of sensor mounting parts are provided on the side wall of the experimental pipeline (17), and the two groups of sensor mounting parts are symmetrically arranged about the axis of the experimental pipeline (17). The sensor mounting parts include a plurality of mounting holes provided on the side wall of the experimental pipeline (17), and the plurality of mounting holes are evenly spaced along the axis of the experimental pipeline (17). The plurality of mounting holes located on one side of the axis of the experimental pipeline (17) are used to mount a plurality of pressure sensors (19), and the plurality of mounting holes located on the other side of the axis of the experimental pipeline (17) are used to mount a plurality of temperature sensors (20); Second mounting holes are respectively provided at both ends of the side wall of the experimental pipeline (17), and two groups of the second mounting holes are used to connect the differential pressure sensor (21).

6. A carbon dioxide near critical point dynamic physical property testing platform according to claim 5, characterized in that: The pressure sensor (19) and the temperature sensor (20) are also connected between the electromagnetic flowmeter (6) and the experimental pipeline (17).

7. A carbon dioxide near-critical point dynamic physical property testing platform according to claim 1, characterized in that: The invention also comprises a cooling system (9), wherein the inlet end and the outlet end of the cooling system (9) are respectively connected to the second connecting pipe (23) through a third connecting pipe (24) and a fourth connecting pipe (25); a fifth connecting pipe (26) is connected between the first connecting pipe (22) and the second connecting pipe (23) at one end close to the discharge tank (8); a first valve (15-1) is connected to the first connecting pipe (22), and the first valve (15-1) is arranged close to the discharge tank (8); the second valve (15-2) and the third valve (15-3) are respectively connected to the fifth connecting pipe (26) and the third connecting pipe (24); the fourth valve (15-4) is connected to the second connecting pipe (23), and the fourth valve (15-4) is located between the third connecting pipe (24) and the fourth connecting pipe (25).

8. A method for testing dynamic physical properties of carbon dioxide near the critical point, based on the platform for testing dynamic physical properties of carbon dioxide near the critical point according to claim 1, characterized in that: The steps include: Installing a plurality of pressure sensors (19), a temperature sensor (20) and a differential pressure sensor (21) on the experimental pipeline (17), and detecting the air tightness of the test platform; The air in the experimental pipeline (17) and the discharge tank (8) is exhausted, and liquid carbon dioxide is charged into the experimental pipeline (17) through the temperature regulator (5) and the electromagnetic flowmeter (6) by the carbon dioxide booster filling assembly; The heating element is started to heat the carbon dioxide in the experimental pipeline (17) to a critical state, and the measured values ​​of each sensor are recorded for calculating the critical physical property parameters of the carbon dioxide in the experimental pipeline (17).

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