Supercritical carbon dioxide closed cycle test system and test method

Abstract

The invention relates to a supercritical carbon dioxide closed cycle test system and a supercritical carbon dioxide closed cycle test method, the system comprises a closed cycle test pipeline, the inlet of the closed cycle test pipeline is connected with the outlet of a liquid carbon dioxide tank through a pre-test pipeline; a supercritical carbon dioxide flow meter, a mass flow meter and a first multi-parameter meter are arranged on the closed cycle test pipeline; an inlet of the pressure regulating pipeline is connected with an outlet of the closed cycle test pipeline; an inlet of the loop pipeline is connected with an outlet of the pressure regulating pipeline, an outlet of the loop pipeline is connected with an inlet of the liquid carbon dioxide tank, and a cooling assembly is arranged on the loop pipeline. When the system is used for operation, the supercritical carbon dioxide closed cycle test method can meet the requirement for accurate calibration of the supercritical carbon dioxide flowmeter, and the method is easy to operate and has good operability.

Description

Technical Field

[0001] The invention relates to a supercritical carbon dioxide closed-cycle test system and a test method, belonging to the technical field of supercritical carbon dioxide. Background Art

[0002] Supercritical carbon dioxide has the characteristics of wide sources and low transportation costs. Its density is close to that of water, its viscosity is close to that of air, and it has good fluidity. It has been increasingly widely studied and applied in oil fields. Among them, downhole injection of supercritical carbon dioxide is a major application direction for supplementing low-layer pressure deficit and increasing oil production.

[0003] However, it is precisely because of these characteristics of supercritical carbon dioxide that when the system heats up, cools down or changes flow, the physical properties of supercritical carbon dioxide (such as viscosity, density, diffusion coefficient, etc.) will change dramatically with temperature and pressure. Therefore, traditional flow meters can no longer accurately measure the injection volume of supercritical carbon dioxide in the injection well, and it is necessary to develop downhole supercritical carbon dioxide flow meters.

[0004] The research directions of supercritical carbon dioxide flowmeters mainly include differential pressure flowmeters and ultrasonic flowmeters. Among them, the measurement parameters of differential pressure flowmeters include factors such as fluid density, viscosity, flow rate, differential pressure, etc., and the measurement parameters of ultrasonic flowmeters include factors such as fluid flow rate, viscosity, and sound velocity. However, there is currently a lack of test calibration devices in China that can meet the above supercritical carbon dioxide flowmeter calibration requirements. Summary of the invention

[0005] In view of the above technical problems, the present invention provides a supercritical carbon dioxide closed-loop test system and test method, which can meet the requirements for accurate calibration of a supercritical carbon dioxide flowmeter.

[0006] To achieve the above object, the present invention adopts the following technical solutions: A supercritical carbon dioxide closed-loop test system, comprising: A closed-loop test pipeline, the inlet of which is connected to the outlet of the liquid carbon dioxide tank through a pre-test pipeline, and the closed-loop test pipeline is provided with a supercritical carbon dioxide flowmeter, a mass flowmeter and a first multi-parameter meter; A pressure regulating pipeline, the inlet of which is connected to the outlet of the closed-loop test pipeline; A loop pipeline, wherein the inlet of the loop pipeline is connected to the outlet of the pressure regulating pipeline, the outlet of the loop pipeline is connected to the inlet of the liquid carbon dioxide tank, and a cooling component is arranged on the loop pipeline.

[0007] In the supercritical carbon dioxide closed-loop test system, preferably, the supercritical carbon dioxide flowmeter comprises: At least one ultrasonic flow meter, disposed on the closed-loop test pipeline, for measuring the real-time volume flow of supercritical carbon dioxide flowing through the ultrasonic flow meter per unit time; and / or, At least one differential pressure flow meter, disposed on the closed-loop test pipeline, for measuring the real-time volume flow of supercritical carbon dioxide flowing through the differential pressure flow meter per unit time; There are multiple first multi-parameter measuring meters, and each of the first multi-parameter measuring meters is connected to one of the differential pressure flowmeters or one of the ultrasonic flowmeters in a one-to-one correspondence.

[0008] The supercritical carbon dioxide closed-loop test system is preferably provided with a circulation pump and a second heating belt on the closed-loop test pipeline, and the second heating belt is used to heat and insulate the closed-loop test pipeline.

[0009] The supercritical carbon dioxide closed-loop test system is preferably provided with a booster pump on the pre-test pipeline and is wrapped with a first heating belt, wherein the booster pump is used to pressurize the liquid carbon dioxide flowing through the pre-test pipeline to a preset pressure, and the first heating belt is used to heat the liquid carbon dioxide flowing through the pre-test pipeline to a preset temperature.

[0010] The supercritical carbon dioxide closed-loop test system preferably also includes a clean water tank, which is arranged in parallel with the liquid carbon dioxide tank and connected to the inlet of the closed-loop test pipeline through the pre-test pipeline. The clean water in the clean water tank is pressurized into the closed-loop test pipeline through the booster pump.

[0011] The supercritical carbon dioxide closed-loop test system is preferably provided with a pressure relief valve, a gaseous carbon dioxide tank, and a second multi-parameter measuring meter on the pressure regulating pipeline; the gaseous carbon dioxide tank is located downstream of the pressure relief valve, and the second multi-parameter measuring meter is located downstream of the gaseous carbon dioxide tank.

[0012] In the supercritical carbon dioxide closed-loop test system, preferably, the cooling component includes a compressor, a condenser and a water chiller, the compressor is located upstream of the condenser, and the water chiller is arranged in parallel with the condenser.

[0013] The supercritical carbon dioxide closed-loop test system is preferably provided with a third multi-parameter meter and a second stop valve on the loop pipeline, wherein the third multi-parameter meter is used to measure the in-line pressure and in-line temperature of the loop pipeline; and the second stop valve controls the on-off of the loop pipeline according to the measurement result of the third multi-parameter meter.

[0014] In the supercritical carbon dioxide closed-loop test system, preferably, the pressure regulating pipeline is further provided with a third heating belt, a second one-way valve and a pressure regulating valve, wherein the second one-way valve is located upstream of the pressure relief valve; and The pre-test pipeline is provided with a first one-way valve, and the loop pipeline is provided with a third one-way valve at a position close to the liquid carbon dioxide tank.

[0015] The test method of the supercritical carbon dioxide closed-loop test system preferably comprises the following steps: S01: pressurizing the liquid carbon dioxide in the liquid carbon dioxide tank to a preset pressure and a preset temperature so that the liquid carbon dioxide is converted into supercritical carbon dioxide; S02: The real-time mass flow of the supercritical carbon dioxide flowing through the supercritical carbon dioxide flowmeter is measured by the mass flow meter within a unit time, and the real-time pressure, real-time pressure difference and real-time temperature of the supercritical carbon dioxide flowing through the supercritical carbon dioxide flowmeter within a unit time are measured by the first multi-parameter measuring meter. When the real-time mass flow increases to be equal to the predetermined mass flow, the real-time mass flow, real-time pressure, real-time pressure difference and real-time temperature are recorded, and the predetermined flow is calculated; S03: Record the real-time flow rate displayed by the supercritical carbon dioxide flowmeter, and determine whether the difference between the predetermined flow rate and the real-time flow rate is within a preset range. If so, proceed to step S04; if not, proceed to step S05; S04: It is concluded that the supercritical carbon dioxide flowmeter does not need to be calibrated; S05: It is concluded that the supercritical carbon dioxide flowmeter needs to be calibrated.

[0016] The test method of the supercritical carbon dioxide closed-loop test system preferably further includes the following step S-1 before step S01: testing the sealing performance of the closed-loop test pipeline by water pressure to see if it is qualified, as follows: S-11: Open the second switch valve, close the first switch valve and the pressure relief valve, and close the pressure regulating valve (507), so that the pressure regulating pipeline is in a blocked state; S-12: Start the booster pump, fill the pre-test pipeline, the closed-loop test pipeline and the pressure regulating pipeline with clean water in the clean water tank until the pressure threshold of the booster pump is reached, and observe whether there is any water leakage in the closed-loop test pipeline; S-13: When the test is qualified, the pressure relief valve is opened to drain the clean water in the pre-test pipeline, the closed-loop test pipeline and the pressure regulating pipeline; S-14: Start the first heating zone, the second heating zone and the third heating zone to 100° C. to vaporize the residual clean water in the pre-test pipeline, the closed-loop test pipeline and the pressure regulating pipeline; S-15: Open the first switch valve, and through the action of the booster pump and the first heating belt, the liquid carbon dioxide can be converted into gaseous carbon dioxide, so that the gasified clean water in the pre-test pipeline, the closed-loop test pipeline and the pressure regulating pipeline is displaced by the gaseous carbon dioxide. After the displacement is completed, close the pressure relief valve.

[0017] The test method of the supercritical carbon dioxide closed-loop test system preferably further comprises, after step S05, step S-2: replenishing the liquid carbon dioxide tank with liquid carbon dioxide, as follows: S-21: determining whether it is necessary to add the carbon dioxide in the gaseous carbon dioxide tank to the liquid carbon dioxide tank according to the display result of the second multi-parameter measuring meter; S-22: If the display result of the second multi-parameter measuring instrument shows that the gaseous carbon dioxide in the gaseous carbon dioxide tank needs to be supplemented into the liquid carbon dioxide tank, first start the water chiller and the condenser, and at the same time close the pressure regulating valve, open the first stop valve, start the compressor, compress the supercritical carbon dioxide flowing through the compressor, and then convert it into the liquid carbon dioxide through the condenser and the water chiller; S-23: Observe the third multi-parameter measuring meter. When the third multi-parameter measuring meter shows that the liquid carbon dioxide meets the supplementary pressure and supplementary temperature, immediately open the second stop valve to allow the liquid carbon dioxide to be supplemented into the liquid carbon dioxide tank.

[0018] The present invention adopts the above technical solution, which has the following advantages: 1. The supercritical carbon dioxide closed-loop test system provided by the present invention, when used specifically, when the real-time mass flow rate increases to be equal to the predetermined mass flow rate, the supercritical carbon dioxide flowmeter can judge whether the supercritical carbon dioxide flowmeter needs to be calibrated based on whether the difference between the predetermined flow rate and the real-time flow rate calculated by the predetermined mass flow rate and the real-time pressure, real-time pressure difference and real-time temperature displayed by the first multi-parameter measuring meter is within a preset range, thereby enabling the supercritical carbon dioxide closed-loop test system to meet the demand for accurate calibration of the supercritical carbon dioxide flowmeter, and the system has a simple composition, is easy to use and has good operability.

[0019] 2. The supercritical carbon dioxide closed-loop test system of the present invention is used for operation, so that the supercritical carbon dioxide closed-loop test method can meet the demand for accurate calibration of a supercritical carbon dioxide flowmeter, and the method is simple to operate and has good operability. BRIEF DESCRIPTION OF THE DRAWINGS

[0020] Figure 1 A schematic diagram of a supercritical carbon dioxide closed-cycle test system provided by one embodiment of the present invention; The reference numerals are as follows: 100-closed loop test pipeline, 1011-ultrasonic flowmeter, 1012-differential pressure flowmeter, 102-mass flowmeter, 103-first multi-parameter meter, 104-circulation pump, 105-second heating belt; 200 - liquid carbon dioxide tank, 201 - first switch valve; 300-pipeline before test, 301-boosting pump, 302-first heating belt, 303-first one-way valve; 400 - clean water tank, 401 - second switch valve; 500-pressure regulating pipeline, 501-pressure relief valve, 502-gaseous carbon dioxide tank, 503-second multi-parameter measuring meter, 504-first stop valve, 505-second one-way valve, 506-third heating belt, 507-pressure regulating valve; 600-loop pipeline, 601-third multi-parameter measuring meter, 602-second stop valve, 603-third check valve; 701-compressor, 702-condenser, 703-chiller. DETAILED DESCRIPTION

[0021] In order to make the purpose, technical solution and advantages of the present invention clearer, the technical solution of the present invention is described clearly and completely below. Obviously, the described embodiments are part of the embodiments of the present invention, not all of the embodiments. Based on the embodiments of the present invention, all other embodiments obtained by ordinary persons in the art without creative work are within the scope of protection of the present invention.

[0022] Unless otherwise defined, the technical or scientific terms used in the present invention shall have the usual meanings understood by persons with ordinary skills in the field to which the present invention belongs. The words "first", "second", "third", "fourth" and similar terms used in the present invention do not indicate any order, quantity or importance, but are only used to distinguish different components. Words such as "include" or "comprise" and the like mean that the elements or objects appearing before the word include the elements or objects listed after the word and their equivalents, without excluding other elements or objects. Words such as "connect" or "connected" and the like are not limited to physical or mechanical connections, but may include electrical connections, whether direct or indirect.

[0023] For ease of description, spatially relative terms may be used herein to describe the relationship of one element or feature relative to another element or feature as shown in the figures, such as "inside", "outside", "inner side", "outer side", "below", "above", etc. Such spatially relative terms are intended to include different orientations of the device in use or operation in addition to the orientation depicted in the figures.

[0024] The research directions of supercritical carbon dioxide flowmeters mainly include differential pressure flowmeters and ultrasonic flowmeters. Among them, the measurement parameters of differential pressure flowmeters include factors such as fluid density, viscosity, flow rate, differential pressure, etc., and the measurement parameters of ultrasonic flowmeters include factors such as fluid flow rate, viscosity, and sound velocity. However, there is currently a lack of test calibration devices in China that can meet the above supercritical carbon dioxide flowmeter calibration requirements.

[0025] Based on the above technical problems, the present invention provides a supercritical carbon dioxide closed-loop test system and test method, which can meet the requirements for accurate calibration of a supercritical carbon dioxide flowmeter.

[0026] like Figure 1 As shown, the supercritical carbon dioxide closed-loop test system provided by the present invention includes a closed-loop test pipeline 100, and a supercritical carbon dioxide flowmeter, a mass flowmeter 102, and a first multi-parameter meter 103 arranged on the closed-loop test pipeline 100. Among them, the inlet end of the closed-loop test pipeline 100 can receive supercritical carbon dioxide pressurized to a preset pressure and a preset temperature; the supercritical carbon dioxide flowmeter is arranged on the closed-loop test pipeline 100, and can measure the real-time flow of supercritical carbon dioxide flowing through the supercritical carbon dioxide flowmeter per unit time; the mass flowmeter 102 is used to measure the real-time mass flow of supercritical carbon dioxide flowing through the supercritical carbon dioxide flowmeter per unit time; the first multi-parameter meter 103 is used to at least measure the real-time pressure, real-time pressure difference, and real-time temperature of supercritical carbon dioxide flowing through the supercritical carbon dioxide flowmeter per unit time.

[0027] Through the above-mentioned settings, when the supercritical carbon dioxide closed-loop test system is used in practice, when the real-time mass flow rate increases to be equal to the predetermined mass flow rate, the supercritical carbon dioxide flowmeter can judge whether the supercritical carbon dioxide flowmeter needs to be calibrated based on whether the difference between the predetermined flow rate and the real-time flow rate calculated by the predetermined mass flow rate and the real-time pressure, real-time pressure difference and real-time temperature displayed by the first multi-parameter measuring meter 103 is within a preset range, thereby enabling the supercritical carbon dioxide closed-loop test system to meet the requirements for accurate calibration of the supercritical carbon dioxide flowmeter, and the system has a simple composition, is easy to use and has good operability.

[0028] In this embodiment, the supercritical carbon dioxide flowmeter includes an ultrasonic flowmeter 1011 and a differential pressure flowmeter 1012. The ultrasonic flowmeter 1011 is arranged on the closed-loop test pipeline 100, and can measure the real-time volume flow rate of supercritical carbon dioxide flowing through the ultrasonic flowmeter 1011 per unit time, and a first multi-parameter measuring meter 103 is arranged near the ultrasonic flowmeter 1011 on the closed-loop pipeline, so that the first multi-parameter measuring meter 103 can judge whether the measurement value of the ultrasonic flowmeter 1011 is accurate by judging whether the difference between the predetermined volume flow rate and the real-time volume flow rate calculated by the displayed real-time pressure, real-time differential pressure and real-time temperature is within a preset range, thereby judging whether the ultrasonic flowmeter 1011 needs to be calibrated.

[0029] In addition, the differential pressure flowmeter 1012 is also arranged on the closed circulation pipeline, and can measure the real-time volume flow rate of supercritical carbon dioxide flowing through the differential pressure flowmeter 1012 per unit time, and a first multi-parameter measuring meter 103 is arranged on the closed circulation pipeline near the differential pressure flowmeter 1012, so that the first multi-parameter measuring meter 103 can judge whether the measurement value of the differential pressure flowmeter 1012 is accurate by judging whether the difference between the predetermined volume flow rate calculated by the displayed real-time pressure, real-time pressure difference and real-time temperature and the real-time volume flow rate is within a preset range, thereby judging whether the differential pressure flowmeter 1012 needs to be calibrated.

[0030] Through the above-mentioned arrangement, the supercritical carbon dioxide closed-loop test system can calibrate the ultrasonic flowmeter 1011 and the differential pressure flowmeter 1012 at the same time, thereby greatly improving the versatility and efficiency of the system.

[0031] It should be noted that in some other embodiments, only one ultrasonic flowmeter 1011 may be set on the closed-loop test pipeline 100, or only one differential pressure flowmeter 1012 may be set, or multiple ultrasonic flowmeters 1011 or multiple differential pressure flowmeters 1012 may be set to meet different calibration requirements. Therefore, the above-mentioned various implementation situations all fall within the scope of protection of the present invention.

[0032] Specifically, the closed-loop test pipeline 100 provided in this embodiment is also provided with a circulation pump 104, and the circulation pump 104 adopts a variable frequency pump. By adopting the variable frequency pump, the circulation pump 104 can gradually adjust the speed and gradually adjust the real-time mass flow rate of the supercritical carbon dioxide in the closed-loop test pipeline 100 to be equal to the predetermined mass flow rate. At the same time, it can also enable the closed-loop test pipeline 100 to meet the use requirements of a variety of mass flow meters with different predetermined mass flow rates, thereby effectively improving the use flexibility of the supercritical carbon dioxide closed-loop test system.

[0033] More specifically, the supercritical carbon dioxide closed-loop test system further includes a liquid carbon dioxide tank 200 and a pre-test pipeline 300. The liquid carbon dioxide tank 200 stores liquid carbon dioxide and is connected to the inlet end of the closed-loop test pipeline 100 through the pre-test pipeline 300 to provide a supercritical carbon dioxide source for the closed-loop test pipeline 100; a booster pump 301 is provided on the pre-test pipeline 300, and a first heating belt 302 is wrapped on the pre-test pipeline 300. The booster pump 301 is used to pressurize the liquid carbon dioxide flowing through the pre-test pipeline 300 to a preset pressure, and the first heating belt 302 is used to heat the liquid carbon dioxide flowing through the pre-test pipeline 300 to a preset temperature, so that the liquid carbon dioxide can be converted into a gaseous carbon dioxide state under the joint action of the booster pump 301 and the first heating belt 302.

[0034] In this embodiment, the supercritical carbon dioxide closed-loop test system can test the sealing of the closed-loop test pipeline 100 by water pressure. Specifically, the supercritical carbon dioxide closed-loop test system also includes a clean water tank 400 and a pressure regulating pipeline 500, wherein the clean water tank 400 is connected in parallel to the liquid carbon dioxide tank 200, and stores clean water, so that the clean water can be pressurized into the closed-loop test pipeline 100 through the pre-test pipeline 300 through the booster pump 301; the inlet end of the pressure regulating pipeline 500 is connected to the outlet end of the closed-loop test pipeline 100, and a pressure relief valve 501 is provided on the pressure regulating pipeline 500, and the pressure relief valve 501 can be opened to empty the clean water in the closed-loop test pipeline 100.

[0035] Exemplarily, when the above-mentioned supercritical carbon dioxide closed-loop test system is used to test the sealing performance of the closed-loop test pipeline 100, the pressure relief valve 501 is first closed, and the pressure regulating pipeline 500 is in a blocked state. Then, the clean water tank 400 is opened and the booster pump 301 is started, so that the booster pump 301 can push the clean water in the clean water tank 400 into the closed-loop test pipeline 100. Since the pressure regulating pipeline 500 is in a blocked state, the clean water will be retained in the closed-loop test pipeline 100. At this time, the booster pump 301 continues to run, thereby continuously pressurizing the clean water in the closed-loop test pipeline 100 until the pressure threshold of the booster pump 301 is reached, and the closed-loop test pipeline 100 is tested for water leakage at this time to determine whether the sealing performance of the closed-loop test pipeline 100 is good. After the pressure test is qualified, the pressure relief valve 501 is opened to drain the water in the closed-loop test pipeline 100 to provide space for the subsequent replenishment of gaseous carbon dioxide.

[0036] More specifically, the outer surface of the closed-loop test pipeline 100 is wrapped with a second heating belt 105, which can heat the closed-loop test pipeline 100 to vaporize the residual clean water attached to the closed-loop test pipeline 100. When gaseous carbon dioxide is subsequently added to the closed-loop test pipeline 100, the gaseous carbon dioxide can discharge the vaporized clean water to ensure that the closed-loop test pipeline is dry and ensure that the environment and test conditions inside the pipeline meet the requirements.

[0037] It should be noted that, in the present embodiment, when the second heating belt 105 heats the closed-loop test pipeline 100, the first heating belt 302 is simultaneously started and heats the pre-test pipeline 300, so that the residual clean water attached to the inner wall of the pre-test pipeline 300 is vaporized, and under the driving action of the gaseous carbon dioxide, it is discharged through the pressure relief valve 501 together with the vaporized clean water in the closed-loop test pipe, thereby further ensuring that the environment of the entire supercritical carbon dioxide closed-loop test system meets the requirements during the test, eliminating the influence on the supercritical carbon dioxide density, air pressure, and temperature, and ensuring the accuracy of the supercritical carbon dioxide flowmeter test.

[0038] It should also be noted that, in the present embodiment, a first switch valve 201 is provided between the liquid carbon dioxide tank 200 and the boosting pump 301, and a second switch valve 401 is provided between the clean water tank 400 and the boosting pump 301. When the first switch valve 201 is opened, the second switch valve 401 is closed to avoid the influence of clean water on the replenishment of liquid carbon dioxide; when the second switch valve 401 is opened, the first switch valve 201 is closed to reduce the influence of liquid carbon dioxide on the sealing of the closed circulation test pipeline 100 for water pressure testing.

[0039] In this embodiment, the supercritical carbon dioxide closed-loop test system also includes a loop pipeline 600 and a cooling component. The inlet end of the loop pipeline 600 is connected to the pressure regulating pipeline 500, and the outlet end of the loop pipeline 600 is connected to the liquid carbon dioxide tank 200. The cooling component can convert the supercritical carbon dioxide flowing through the loop pipeline 600 into liquid carbon dioxide, thereby replenishing liquid carbon dioxide for the liquid carbon dioxide tank 200, saving the use of liquid carbon dioxide, reducing the consumption of liquid carbon dioxide, and thus reducing energy and cost consumption.

[0040] Specifically, in the present embodiment, a gaseous carbon dioxide tank 502, a second multi-parameter measuring meter 503 and a first stop valve 504 are provided on the pressure regulating pipeline 500. The gaseous carbon dioxide tank 502 is located downstream of the pressure relief valve 501, and can receive supercritical carbon dioxide that exceeds the preset pressure to ensure that the actual pressure of the supercritical carbon dioxide in the closed-loop test pipeline 100 is equal to the preset pressure, and prevent the actual pressure of the supercritical carbon dioxide in the closed-loop test pipeline 100 from being too high, causing the closed-loop test pipeline 100 to crack, thereby ensuring the safety of the test process. In addition, the second multi-parameter measuring meter 503 is used to measure the tank pressure and tank temperature of the carbon dioxide in the gaseous carbon dioxide tank 502, and the first stop valve 504 is located between the gaseous carbon dioxide tank 502 and the loop pipeline 600, and can control the on-off between the gaseous carbon dioxide tank 502 and the loop pipeline 600 according to the measurement result of the second multi-parameter measuring meter 503.

[0041] Exemplarily, when the supercritical carbon dioxide closed-loop test system is in use, when the second multi-parameter measuring meter 503 detects that the pressure in the tank or the temperature in the tank exceeds the set value, the first stop valve 504 can be opened to connect the gaseous carbon dioxide tank 502 and the loop pipeline 600, so that the carbon dioxide in the gaseous carbon dioxide tank 502 can enter the cooling component through the loop pipeline 600, and the gaseous carbon dioxide is converted into liquid carbon dioxide through the cooling component, and then replenished into the liquid carbon dioxide tank 200 through the loop pipeline 600. Through the above arrangement, on the one hand, the supercritical carbon dioxide exceeding the preset pressure is collected by the gaseous carbon dioxide tank 502, so that the closed-loop test pipeline 100 is free from the risk of rupture and explosion; on the other hand, through the second multi-parameter measuring meter 503 and the first stop valve 504, it can be ensured that the pressure in the gaseous carbon dioxide tank 502 is kept within a safe range, and the gaseous carbon dioxide tank 502 is prevented from being damaged due to excessive pressure and temperature in the gaseous carbon dioxide tank 502, thereby greatly improving the safety and reliability of the entire supercritical carbon dioxide closed-loop test system.

[0042] More specifically, in this embodiment, the cooling assembly mainly includes a compressor 701, a condenser 702 and a chiller 703. The compressor 701 is located downstream of the first stop valve 504 and upstream of the condenser 702 and the chiller 703. The compressor 701 first compresses the supercritical carbon dioxide to a higher pressure and then delivers it to the condenser 702. In the condenser 702, the gaseous carbon dioxide releases heat and cools to become liquid, so that the pressure and temperature of the liquid carbon dioxide can meet the storage requirements of the liquid carbon dioxide tank 200.

[0043] More specifically, in this embodiment, a third multi-parameter meter 601 and a second stop valve 602 are also provided on the loop pipeline 600. The third multi-parameter meter 601 is used to measure the in-line pressure and in-line temperature of the loop pipeline 600 to determine the state of carbon dioxide in the loop pipeline 600. When the measurement results show that the in-line pressure and in-line temperature are within a suitable range, it indicates that the carbon dioxide in the loop pipeline 600 is now all in the state of liquid carbon dioxide. At this time, the second stop valve 602 controls the loop pipeline 600 to be in an open state according to the measurement results of the third multi-parameter meter 601, so that the blocked liquid carbon dioxide can be smoothly replenished into the liquid carbon dioxide tank 200, so that the excess supercritical carbon dioxide in the gaseous carbon dioxide tank 502 is pressurized and injected back into the liquid carbon dioxide tank 200 after being gasified and liquefied, thereby saving carbon dioxide resources.

[0044] Optionally, in this embodiment, a first one-way valve 303 is provided between the pre-test pipeline 300 and the closed-loop test pipeline 100, a second one-way valve 505 is provided between the closed-loop test pipeline 100 and the pressure regulating pipeline 500, and a third one-way valve 603 is provided on the loop pipeline 600 near the liquid carbon dioxide tank 200, so that the first one-way valve 303, the second one-way valve 505 and the third one-way valve 603 can be used to ensure that the fluid can only flow in one direction in the set direction, prevent backflow and leakage, and thus ensure the safety of the supercritical carbon dioxide closed-loop test system.

[0045] The second aspect of the present invention also provides a test method for a supercritical carbon dioxide closed-loop test system, comprising the following steps: S01: pressurizing the liquid carbon dioxide to a preset pressure and a preset temperature so that the liquid carbon dioxide is converted into a supercritical carbon dioxide state.

[0046] Specifically, a pressure regulating valve 507 is also provided on the pressure regulating pipeline 500. Figure 1 As shown, the pressure regulating valve 507 is located downstream of the pressure relief valve 501 .

[0047] When this step S01 is implemented, it specifically includes the following steps: S011: Pressurization stage. Open the first switch valve 201, close the pressure relief valve 501 and the pressure regulating valve 507, so that the pressure regulating pipeline 500 is in a blocked state at this time; then, start the booster pump 301, fill the pre-test pipeline 300, the closed cycle test pipeline 100 and the pressure regulating pipeline 500 with the liquid carbon dioxide in the liquid carbon dioxide tank 200 in turn, and continue to pressurize the liquid carbon dioxide until the pressure reaches the pressure threshold of the booster pump 301.

[0048] S012: Temperature adjustment stage. The first heating belt 302 and the second heating belt 105 are started to heat the temperature of the pre-test pipeline 300 and the closed-loop test pipeline 100 to a preset temperature. When the temperature is higher than the preset temperature, the first heating belt 302 and the second heating belt 105 are stopped to reduce the temperature of the pre-test pipeline 300 and the closed-loop test pipeline 100 to the preset temperature.

[0049] It should be noted that, in the present embodiment, both the first heating belt 302 and the second heating belt 105 use electric heating tapes, so that the first heating belt 302 and the second heating belt 105 have a self-control temperature function, and can quickly heat up and keep warm to a preset temperature by electric heating, and there is no insulation layer in the first heating belt 302 and the second heating belt 105. When cooling is required, the electric heating is stopped immediately, and natural cooling can be achieved in a relatively short time, thereby ensuring that the temperature of the supercritical carbon dioxide can always be stably maintained within an acceptable range of the preset temperature, which helps to improve the accuracy of the experimental results.

[0050] S013: Pressure regulation stage. A third heating belt 506 is wrapped around the outer surface of the pressure regulating pipeline 500. The third heating belt 506 is started, and the first stop valve 504 is closed to heat the pressure regulating pipeline 500. When the pressure in the closed-loop test pipeline 100 exceeds the preset pressure, the pressure regulating valve 507 is started so that the supercritical carbon dioxide exceeding the preset pressure can enter the gaseous carbon dioxide tank 502 to reduce the pressure in the closed-loop test pipeline 100. When the pressure in the closed-loop test pipeline 100 is reduced to the preset pressure, the pressure regulating valve 507 is closed so that the pressure of the supercritical carbon dioxide can be maintained within an acceptable range of the preset pressure. Through the above-mentioned temperature adjustment stage and pressure adjustment stage, the real-time pressure and real-time temperature of the supercritical carbon dioxide in the closed-loop test pipeline 100 can be adjusted to the range of the preset pressure and the preset temperature, thereby providing stable test conditions for the subsequent test stage and helping to obtain more reliable test data.

[0051] S02: The real-time mass flow of the supercritical carbon dioxide flowing through the supercritical carbon dioxide flowmeter in unit time is measured by the mass flow meter 102, and the real-time pressure, real-time pressure difference and real-time temperature of the supercritical carbon dioxide flowing through the supercritical carbon dioxide flowmeter in unit time are measured by the first multi-parameter meter 103. When the real-time mass flow increases to be equal to the predetermined mass flow, the real-time mass flow, real-time pressure, real-time pressure difference and real-time temperature are recorded, and the predetermined flow is calculated.

[0052] During the specific implementation of step S02, the circulation pump 104 is first started to allow the supercritical carbon dioxide in the closed-loop test pipeline 100 to circulate in the closed-loop test pipeline 100, and the circulation pump 104 continuously adjusts the circulation speed of the supercritical carbon dioxide in the closed-loop test pipeline 100 until the real-time mass flow rate displayed by the mass flow meter increases to a level equal to the predetermined mass flow rate, and then the real-time pressure, real-time pressure difference and real-time temperature data displayed by the two first multi-parameter measuring meters 103 are simultaneously recorded, and the predetermined volume flow rate and the predetermined pressure difference flow rate are respectively calculated based on the real-time pressure, real-time pressure difference and real-time temperature data.

[0053] S03: Record the real-time flow rate displayed by the supercritical carbon dioxide flowmeter, and determine whether the difference between the predetermined flow rate and the real-time flow rate is within a preset range. If so, proceed to step S05; if not, proceed to step S06; In the specific implementation of this step S03, the real-time volume flow of the ultrasonic flowmeter 1011 and the differential pressure flowmeter 1012 are recorded respectively, and the predetermined volume flow and the real-time volume flow are compared respectively, so as to judge whether the detection value of the ultrasonic flowmeter 1011 is accurate according to whether the difference between the predetermined volume flow and the real-time volume flow is within the preset range, and then judge whether it is necessary to calibrate the ultrasonic flowmeter 1011. Similarly, judge whether the detection value of the differential pressure flowmeter 1012 is accurate, and then judge whether it is necessary to calibrate the differential pressure flowmeter 1012. If it is within the preset range, continue to execute step S04; otherwise, continue to execute step S05.

[0054] S04: Conclusion: Supercritical CO2 flowmeter does not require calibration; In this step, it is concluded that the ultrasonic flowmeter 1011 and the differential pressure flowmeter 1012 do not need to be calibrated.

[0055] S05: Conclusion: The supercritical carbon dioxide flowmeter needs to be calibrated.

[0056] In this step, it is concluded that the ultrasonic flowmeter 1011 and the differential pressure flowmeter 1012 need to be calibrated.

[0057] Through the above-mentioned test method, when the supercritical carbon dioxide closed-loop test method is used in practice, the supercritical carbon dioxide flowmeter can judge whether the supercritical carbon dioxide flowmeter needs to be calibrated based on whether the difference between the predetermined flow and the real-time flow calculated by the predetermined mass flow and the real-time pressure, real-time pressure difference and real-time temperature displayed by the first multi-parameter measuring meter 103 is within a preset range, thereby enabling the supercritical carbon dioxide closed-loop test system to meet the requirements for accurate calibration of the supercritical carbon dioxide flowmeter, and the system has a simple composition, is easy to use and has good operability.

[0058] It should be noted that, in this test method, before step S01, the following steps are also included: S-1: Hydrostatic test of the closed-loop test pipeline 100 to see if the sealing is up to standard.

[0059] When this step S-1 is implemented, it specifically includes the following steps: S-11: Open the second switch valve 401, close the first switch valve 201, close the pressure relief valve 501, and close the pressure regulating valve 507, so that the pressure regulating pipeline 500 is in a blocked state.

[0060] S-12: Start the booster pump 301, fill the pre-test pipeline 300, the closed-loop test pipeline 100 and the pressure regulating pipeline 500 with clean water in the clean water tank 400, and continue to pressurize the clean water until the pressure threshold of the booster pump 301 is reached, and observe whether there is any water leakage in the closed-loop test pipeline 100.

[0061] S-13: When the test is passed, open the pressure relief valve 501 to drain the clean water in the pre-test pipeline 300, the closed-loop test pipeline 100 and the pressure regulating pipeline 500.

[0062] S-14: Start the first heating belt 302, the second heating belt 105 and the third heating belt 506. Preferably, in this embodiment, the first heating belt 302, the second heating belt 105 and the third heating belt 506 are heated to 100°C to completely vaporize the residual clean water in the pre-test pipeline 300, the closed-loop test pipeline 100 and the pressure regulating pipeline 500, and at the same time close the second switch valve 401 to stop the delivery of clean water.

[0063] S-15: Open the first switch valve 201, and through the action of the booster pump 301 and the first heating belt 302, the liquid carbon dioxide can be converted into gaseous carbon dioxide, so that after the gasified clean water in the pipeline 300 before the test, the closed-loop test pipeline 100 and the pressure regulating pipeline 500 is displaced by the gaseous carbon dioxide, the pressure relief valve 501 is closed.

[0064] It should be noted that, in this test method, after step S05, the following steps are further included: S-2: Replenish the liquid carbon dioxide tank 200 with liquid carbon dioxide.

[0065] When this step S-2 is implemented, it specifically includes the following steps: S-21: Determine whether it is necessary to add the gaseous carbon dioxide in the gaseous carbon dioxide tank 502 to the liquid carbon dioxide tank 200 according to the display result of the second multi-parameter measuring meter 503 .

[0066] S-22: If the display result of the second multi-parameter measuring meter 503 shows that the gaseous carbon dioxide in the gaseous carbon dioxide tank 502 needs to be supplemented into the liquid carbon dioxide tank 200, first start the chiller 703 and the condenser 702, and at the same time close the pressure regulating valve 507, open the first stop valve 504, start the compressor 701, compress the supercritical carbon dioxide flowing through the compressor 701, and then convert it into liquid carbon dioxide through the condenser 702 and the chiller 703.

[0067] S-23: Observe the third multi-parameter measuring meter 601. When the third multi-parameter measuring meter 601 shows that the liquid carbon dioxide at this time meets the supplementary pressure and supplementary temperature, immediately open the second stop valve 602 to allow the liquid carbon dioxide to be supplemented into the liquid carbon dioxide tank 200.

[0068] In the description of this specification, the description with reference to the terms "some embodiments", "other embodiments", etc. means that the specific features, structures, materials or characteristics described in conjunction with the embodiment or example are included in at least one embodiment or example of the present invention. In this specification, the schematic representation of the above terms does not necessarily refer to the same embodiment or example. Moreover, the specific features, structures, materials or characteristics described can be combined in any one or more embodiments or examples in a suitable manner.

[0069] Finally, it should be noted that the above embodiments are only used to illustrate the technical solutions of the present invention, rather than to limit it. Although the present invention has been described in detail with reference to the aforementioned embodiments, those skilled in the art should understand that they can still modify the technical solutions described in the aforementioned embodiments, or make equivalent replacements for some of the technical features therein. However, these modifications or replacements do not deviate the essence of the corresponding technical solutions from the spirit and scope of the technical solutions of the embodiments of the present invention.

Claims

1. A supercritical carbon dioxide closed-loop test system, characterized in that: include: A closed-loop test pipeline (100), wherein the inlet of the closed-loop test pipeline (100) is connected to the outlet of the liquid carbon dioxide tank (200) via a pre-test pipeline (300), and the closed-loop test pipeline (100) is provided with a supercritical carbon dioxide flowmeter, a mass flowmeter (102), and a first multi-parameter meter (103); A pressure regulating pipeline (500), wherein the inlet of the pressure regulating pipeline (500) is connected to the outlet of the closed-loop test pipeline (100); A loop pipeline (600), wherein the inlet of the loop pipeline (600) is connected to the outlet of the pressure regulating pipeline (500), the outlet of the loop pipeline (600) is connected to the inlet of the liquid carbon dioxide tank (200), and a cooling component is provided on the loop pipeline (600).

2. The supercritical carbon dioxide closed cycle test system according to claim 1, characterized in that: The supercritical carbon dioxide flowmeter comprises: at least one ultrasonic flow meter (1011), arranged on the closed-loop test pipeline (100), for measuring the real-time volume flow of supercritical carbon dioxide flowing through the ultrasonic flow meter (1011) per unit time; and / or, At least one differential pressure flow meter (1012), arranged on the closed-loop test pipeline (100), and used to measure the real-time volume flow of supercritical carbon dioxide flowing through the differential pressure flow meter (1012) per unit time; A plurality of the first multi-parameter measuring meters (103) are provided, and each of the first multi-parameter measuring meters (103) is connected in a one-to-one correspondence with one of the differential pressure flowmeters (1012) or one of the ultrasonic flowmeters (1011).

3. The supercritical carbon dioxide closed cycle test system according to claim 2, characterized in that: The closed-loop test pipeline (100) is also provided with a circulation pump (104) and a second heating belt (105), wherein the second heating belt (105) is used to heat and keep the closed-loop test pipeline (100) warm.

4. The supercritical carbon dioxide closed cycle test system according to claim 3, characterized in that: The pre-test pipeline (300) is provided with a booster pump (301) and is wrapped with a first heating belt (302). The booster pump (301) is used to pressurize the liquid carbon dioxide flowing through the pre-test pipeline (300) to a preset pressure, and the first heating belt (302) is used to heat the liquid carbon dioxide flowing through the pre-test pipeline (300) to a preset temperature.

5. The supercritical carbon dioxide closed cycle test system according to claim 4, characterized in that: The system further comprises a clean water tank (400), the clean water tank (400) being arranged in parallel with the liquid carbon dioxide tank (200) and connected to the inlet of the closed-loop test pipeline (100) via the pre-test pipeline (300), and the clean water in the clean water tank (400) being pressurized into the closed-loop test pipeline (100) via the booster pump (301).

6. The supercritical carbon dioxide closed-loop test system according to claim 5, characterized in that: The pressure regulating pipeline (500) is provided with a pressure relief valve (501), a gaseous carbon dioxide tank (502), and a second multi-parameter measuring meter (503); the gaseous carbon dioxide tank (502) is located downstream of the pressure relief valve (501), and the second multi-parameter measuring meter (503) is located downstream of the gaseous carbon dioxide tank (502).

7. The supercritical carbon dioxide closed cycle test system according to claim 6, characterized in that: The cooling component comprises a compressor (701), a condenser (702) and a water chiller (703); the compressor (701) is located upstream of the condenser (702), and the water chiller (703) is arranged in parallel with the condenser (702).

8. The supercritical carbon dioxide closed cycle test system according to claim 7, characterized in that: The loop pipeline (600) is also provided with a third multi-parameter measuring meter (601) and a second stop valve (602). The third multi-parameter measuring meter (601) is used to measure the in-line pressure and in-line temperature of the loop pipeline (600); and the second stop valve (602) controls the on-off of the loop pipeline (600) according to the measurement result of the third multi-parameter measuring meter (601).

9. The supercritical carbon dioxide closed cycle test system according to claim 8, characterized in that: The pressure regulating pipeline (500) is further provided with a third heating belt (506), a second one-way valve (505) and a pressure regulating valve (507), wherein the second one-way valve (505) is located upstream of the pressure relief valve (501); and, The pre-test pipeline (300) is provided with a first one-way valve (303), and the loop pipeline (600) is provided with a third one-way valve (603) at a position close to the liquid carbon dioxide tank (200).

10. The test method of the supercritical carbon dioxide closed cycle test system according to claim 9, characterized in that: The steps include: S01: pressurizing the liquid carbon dioxide in the liquid carbon dioxide tank (200) to a preset pressure and a preset temperature, so that the liquid carbon dioxide is converted into supercritical carbon dioxide; S02: measuring the real-time mass flow of the supercritical carbon dioxide flowing through the supercritical carbon dioxide flowmeter within a unit time by means of the mass flow meter (102), measuring the real-time pressure, real-time differential pressure and real-time temperature of the supercritical carbon dioxide flowing through the supercritical carbon dioxide flowmeter within a unit time by means of the first multi-parameter meter (103), and when the real-time mass flow increases to be equal to the predetermined mass flow, recording the real-time mass flow, real-time pressure, real-time differential pressure and real-time temperature, and calculating the predetermined flow; S03: Record the real-time flow rate displayed by the supercritical carbon dioxide flowmeter, and determine whether the difference between the predetermined flow rate and the real-time flow rate is within a preset range. If so, proceed to step S04; if not, proceed to step S05; S04: It is concluded that the supercritical carbon dioxide flowmeter does not need to be calibrated; S05: It is concluded that the supercritical carbon dioxide flowmeter needs to be calibrated.

11. The test method of the supercritical carbon dioxide closed cycle test system according to claim 10, characterized in that: Before step S01, the method further includes the following step S-1: testing the sealing performance of the closed-loop test pipeline (100) by water pressure to determine whether it is qualified, as follows: S-11: opening the second switch valve (401), closing the first switch valve (201) and the pressure relief valve (501), and closing the pressure regulating valve (507), so that the pressure regulating pipeline (500) is in a blocked state; S-12: starting the booster pump (301) to fill the pre-test pipeline (300), the closed-loop test pipeline (100) and the pressure regulating pipeline (500) with clean water in the clean water tank (400) until the pressure threshold of the booster pump (301) is reached, and observing whether there is any water leakage in the closed-loop test pipeline (100); S-13: When the test is qualified, the pressure relief valve (501) is opened to drain the clean water in the pre-test pipeline (300), the closed-loop test pipeline (100) and the pressure regulating pipeline (500); S-14: starting the first heating zone (302), the second heating zone (105) and the third heating zone (506) to 100° C. to vaporize the residual clean water in the pre-test pipeline (300), the closed-loop test pipeline (100) and the pressure regulating pipeline (500); S-15: Open the first switch valve (201), and through the action of the booster pump (301) and the first heating belt (302), the liquid carbon dioxide can be converted into gaseous carbon dioxide, so that the gasified clean water in the pre-test pipeline (300), the closed-loop test pipeline (100) and the pressure regulating pipeline (500) is displaced by the gaseous carbon dioxide. After the displacement is completed, close the pressure relief valve (501).

12. The test method of the supercritical carbon dioxide closed cycle test system according to claim 10, characterized in that: After step S05, the method further includes step S-2: replenishing the liquid carbon dioxide tank (200) with liquid carbon dioxide, specifically as follows: S-21: determining whether it is necessary to replenish the carbon dioxide in the gaseous carbon dioxide tank (502) into the liquid carbon dioxide tank (200) according to the display result of the second multi-parameter measuring meter (503); S-22: If the display result of the second multi-parameter measuring meter (503) shows that the gaseous carbon dioxide in the gaseous carbon dioxide tank (502) needs to be supplemented into the liquid carbon dioxide tank (200), firstly start the water chiller (703) and the condenser (702), and at the same time close the pressure regulating valve (507), open the first stop valve (504), start the compressor (701), compress the supercritical carbon dioxide flowing through the compressor (701), and then convert it into the liquid carbon dioxide through the condenser (702) and the water chiller (703); S-23: Observe the third multi-parameter measuring meter (601). When the third multi-parameter measuring meter (601) shows that the liquid carbon dioxide meets the replenishment pressure and replenishment temperature, immediately open the second stop valve (602) to allow the liquid carbon dioxide to be replenished into the liquid carbon dioxide tank (200).

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