Standard meter method liquid flow calibration device and method based on non-isothermal loop

Abstract

The invention discloses a standard meter method liquid flow calibration device and method based on a non-isothermal loop. The device comprises a high-temperature and high-pressure heat exchange system, a high-temperature heating system, a secondary cooling system, a pressure stabilizing system, a high-temperature flow adjusting valve, a high-temperature area temperature and pressure instrument, a detected high-temperature and high-pressure flowmeter, a pressure reducing system, a low-temperature flow adjusting valve, a low-temperature area temperature and pressure instrument, a standard high-temperature and high-pressure flowmeter, a low-temperature area safety valve and a water pump. And a high-temperature area safety valve and exhaust valve system. By means of the device, the high-temperature and high-pressure medium flow and the low-temperature and low-pressure medium flow can be compared in one circulating device at the same time, and therefore liquid flow calibration through a standard meter method is achieved.

Description

Technical Field

[0001] The invention relates to the technical field of flow measurement, and in particular to a standard meter method liquid flow calibration device and method based on a non-isothermal loop. Background Art

[0002] In the petroleum, chemical, electric power and other industries, liquid flow measurement under high temperature and high pressure medium conditions is widely valued, and its accuracy is usually a key indicator that determines the number of trade transfers, system safety, and system working efficiency. However, in view of the limitations of existing technologies, safety design requirements and other aspects, most of the existing liquid flow calibration devices are suitable for normal temperature media or media links not exceeding 80°C, and cannot meet the calibration requirements under high temperature and high pressure conditions. In addition, liquid media under high temperature and high pressure environments are prone to contain gas, which will interfere with flow measurement and affect the accuracy of the calibration results. Therefore, there is a need for a device that can perform liquid flow calibration under high temperature and high pressure medium conditions to solve the measurement problem of high temperature and high pressure liquid flow meters. Summary of the invention

[0003] In view of the deficiencies in the prior art, the present invention aims to provide a standard meter method liquid flow calibration device and method based on an isothermal loop to solve the flow measurement problem of liquid media such as water and oil under high temperature and high pressure conditions.

[0004] In order to achieve the above object, the present invention adopts the following technical solution:

[0005] A standard meter method liquid flow calibration device based on a non-isothermal loop, comprising a high temperature and high pressure heat exchange system, a high temperature heating system, a secondary cooling system, a pressure stabilizing system, a high temperature flow regulating valve, a high temperature zone temperature and pressure instrument, a high temperature and high pressure flow meter to be tested, a pressure reducing system, a low temperature flow regulating valve, a low temperature zone temperature and pressure instrument, a standard high temperature and high pressure flow meter, a low temperature zone safety valve, a water pump, a high temperature zone safety valve and an exhaust valve system;

[0006] The two sides of the high-temperature and high-pressure heat exchange system are respectively a high-temperature zone and a low-temperature zone; in the low-temperature zone, the pressure reduction system, the low-temperature flow regulating valve, the low-temperature zone temperature and pressure instrument, the standard high-temperature and high-pressure flow meter, the secondary cooling system, the low-temperature zone safety valve and the water pump are connected in sequence; in the high-temperature zone, the high-temperature zone safety valve, the high-temperature heating system, the exhaust valve system, the pressure stabilizing system, the high-temperature flow regulating valve, the high-temperature zone temperature and pressure instrument and the tested high-temperature and high-pressure flow meter are connected in sequence; the high-temperature and high-pressure heat exchange system at least includes a cold medium heating channel and a hot medium cooling channel; the outlet of the water pump is connected to the inlet of the cold medium heating channel of the high-temperature and high-pressure heat exchange system, The inlet of the high-temperature zone safety valve is connected to the outlet of the cold medium heating channel of the high-temperature and high-pressure heat exchange system, the outlet of the tested high-temperature and high-pressure flowmeter is connected to the inlet of the hot medium cooling channel of the high-temperature and high-pressure heat exchange system, and the inlet of the pressure reducing system is connected to the outlet of the hot medium cooling channel of the high-temperature and high-pressure heat exchange system; the cold medium enters the high-temperature and high-pressure heat exchange system from the inlet of the cold medium heating channel, becomes the hot medium through heat exchange, and is discharged from the outlet of the cold medium heating channel into the high-temperature zone; the hot medium enters the high-temperature and high-pressure heat exchange system from the inlet of the hot medium cooling channel, becomes the cold medium through heat exchange, and is discharged from the outlet of the hot medium cooling channel into the low-temperature zone.

[0007] Furthermore, the safety valve system in the high temperature zone, the high temperature heating system, the exhaust valve system, the pressure stabilizing system, the high temperature flow regulating valve, the temperature and pressure instrument in the high temperature zone and the high temperature and high pressure flow meter under test are connected through high temperature and high pressure resistant stainless steel pipes.

[0008] Furthermore, the connections between each high-temperature and high-pressure resistant stainless steel pipeline and the high-temperature area safety valve, high-temperature heating system, exhaust valve system, pressure stabilizing system, high-temperature flow regulating valve, high-temperature area temperature and pressure instrument and the high-temperature and high-pressure flow meter under inspection are welded or connected by high-temperature and high-pressure sealing to ensure no leakage.

[0009] Furthermore, the pressure stabilizing system includes a pressure stabilizing valve and a pressure stabilizing container which are connected in series.

[0010] Furthermore, the calibration device also includes a high-temperature and high-pressure stainless steel bellows expansion joint, which is connected to the top of the pressure-stabilizing container through a flange to compensate for the volume change of the liquid medium caused by temperature change.

[0011] Furthermore, the high temperature heating system adopts electric heating or heat exchange, and is equipped with a temperature control system for accurately controlling the heating temperature.

[0012] Furthermore, the water pump meets the design requirements of high pressure resistance, the flow range should cover the design value of the high temperature and high pressure heat exchange system, and the head range should be higher than the overall pressure loss of the calibration device.

[0013] Furthermore, the secondary cooling system adopts a water cooling method, including a cooling circulation pump and a radiator.

[0014] Furthermore, the low temperature zone pressure reducing system, low temperature flow regulating valve, low temperature zone temperature and pressure instrument, standard high temperature and high pressure flow meter, secondary cooling system, low temperature zone safety valve and water pump are connected by high temperature and high pressure resistant stainless steel pipes.

[0015] The present invention also provides a method for calibrating the liquid flow rate using the standard meter method based on the non-isothermal loop, the specific process is:

[0016] Heating and exhausting stage: First, fill the calibration device with liquid medium, close the secondary cooling system, close the high-temperature flow regulating valve and the high-temperature zone safety valve, heat the liquid medium to the set first temperature through the high-temperature heating system, then open the high-temperature flow regulating valve and the high-temperature zone safety valve, keep the high-temperature heating system in working state, start the water pump, make the liquid medium move at a lower flow rate, and gradually exhaust the gas contained in the liquid medium through the exhaust valve system; in the heating and exhausting stage, the liquid medium is slowly heated and is lower than the first temperature;

[0017] Temperature and pressure increase stage: After the gas contained in the liquid medium is fully discharged, the liquid medium is kept circulating at a relatively low flow rate, the power of the high-temperature heating system is increased to heat the liquid medium in the high-temperature zone, and the secondary cooling system is turned on to cool the liquid medium in the low-temperature zone, so that the liquid medium in the high-temperature zone gradually reaches the expected high-temperature and high-pressure state, and the liquid medium in the low-temperature zone also gradually reaches the expected low-temperature and low-pressure state;

[0018] Test phase: After the temperature and pressure of the high temperature zone and the low temperature zone reach the preset values, that is, after the non-isothermal medium conditions are formed, the power of the water pump is increased. Driven by the water pump, the liquid medium passes through the high temperature and high pressure flowmeter to be tested and the standard high temperature and high pressure flowmeter at the set flow rate. At this time, the flow rate, temperature and pressure of the liquid medium also reach a stable state, and the calibration of the high temperature and high pressure flowmeter to be tested can be started;

[0019] Calibration phase: maintain the liquid medium at the set flow rate, temperature and pressure state, take the set time as one measurement, repeat the measurement n times, and simultaneously record the measurement values ​​of the high temperature zone temperature and pressure instrument, the tested high temperature and high pressure flowmeter, the low temperature zone temperature and pressure instrument and the standard high temperature and high pressure flowmeter. The average value of the temperature and pressure of the liquid medium in the high temperature zone and the temperature and pressure of the liquid medium in the low temperature zone are used as the current calibration medium conditions, and the flow measurement result Q of the standard high temperature and high pressure flowmeter for the i-th time is used as the calibration medium condition. si and the i-th flow measurement result Q of the high temperature and high pressure flowmeter under test biFor comparison, the high temperature and high pressure flow meter under test is calibrated; the calibration result is expressed in relative indication error and repeatability, and the single relative indication error is:

[0020]

[0021] The relative indication error of the current flow point is:

[0022]

[0023] Where n is the number of repeated measurements;

[0024] The repeatability of the current flow point is:

[0025]

[0026] Cooling and pressure reduction stage: After the test is completed, turn off the high-temperature heating system, open the low-temperature zone safety valve and the high-temperature zone safety valve to quickly release the pressure, or do not open the low-temperature zone safety valve and the high-temperature zone safety valve, and wait for the liquid medium to cool down naturally until it returns to normal temperature and pressure.

[0027] The beneficial effect of the present invention is that by using the present invention, the high-temperature and high-pressure medium flow and the low-temperature and low-pressure liquid medium flow can be simultaneously realized in a set of circulation devices, thereby realizing the liquid flow calibration using the standard meter method. BRIEF DESCRIPTION OF THE DRAWINGS

[0028] Figure 1 It is a structural schematic diagram of the standard meter method liquid flow calibration device based on the non-isothermal loop in Example 1 of the present invention. DETAILED DESCRIPTION

[0029] The present invention will be further described below in conjunction with the accompanying drawings. It should be noted that this embodiment is based on the technical solution and provides a detailed implementation method and specific operation process, but the protection scope of the present invention is not limited to this embodiment.

[0030] Example 1

[0031] This embodiment provides a standard meter method liquid flow calibration device based on a non-isothermal loop, such as Figure 1 As shown, it includes a high-temperature and high-pressure heat exchange system 1, a high-temperature heating system 2, a secondary cooling system 3, a pressure stabilizing system 4, a high-temperature flow regulating valve 5, a high-temperature zone temperature and pressure instrument 6, a tested high-temperature and high-pressure flow meter 7, a pressure reducing system 8, a low-temperature flow regulating valve 9, a low-temperature zone temperature and pressure instrument 10, a standard high-temperature and high-pressure flow meter 11, a low-temperature zone safety valve 12, a water pump 13, a high-temperature zone safety valve 14 and an exhaust valve system 15.

[0032] The two sides of the high-temperature and high-pressure heat exchange system 1 are respectively a high-temperature zone and a low-temperature zone; in the low-temperature zone, a pressure reducing system 8, a low-temperature flow regulating valve 9, a low-temperature zone temperature and pressure instrument 10, a standard high-temperature and high-pressure flow meter 11, a secondary cooling system 3, a low-temperature zone safety valve 12 and a water pump 13 are connected in sequence; in the high-temperature zone, a high-temperature zone safety valve 14, a high-temperature heating system 2, an exhaust valve system 15, a pressure stabilizing system 4, a high-temperature flow regulating valve 5, a high-temperature zone temperature and pressure instrument 6 and a high-temperature and high-pressure flow meter 7 to be tested are connected in sequence; the high-temperature and high-pressure heat exchange system at least includes a cold medium heating channel and a hot medium cooling channel; the outlet of the water pump 13 is connected to the cold medium of the high-temperature and high-pressure heat exchange system 1 The inlet of the high temperature zone safety valve 14 is connected to the outlet of the cold medium heating channel of the high temperature and high pressure heat exchange system 1, the outlet of the tested high temperature and high pressure flowmeter 7 is connected to the inlet of the hot medium cooling channel of the high temperature and high pressure heat exchange system 1, and the inlet of the decompression system 8 is connected to the outlet of the hot medium cooling channel of the high temperature and high pressure heat exchange system 1; the cold medium enters the high temperature and high pressure heat exchange system from the inlet of the cold medium heating channel, becomes the hot medium through heat exchange, and is discharged to the high temperature zone from the outlet of the cold medium heating channel; the hot medium enters the high temperature and high pressure heat exchange system from the inlet of the hot medium cooling channel, becomes the cold medium through heat exchange, and is discharged to the low temperature zone from the outlet of the hot medium cooling channel.

[0033] The high-temperature and high-pressure heat exchange system 1 is used to realize heat exchange between the hot medium in the high-temperature zone and the cold medium in the low-temperature zone, so as to form an isothermal loop with a cold medium on one side and a hot medium on the other side in a set of devices.

[0034] The high temperature heating system 2 is used to provide a stable heat source for the calibration device to maintain the required high temperature environment. When the calibration device is initially cold, the high temperature heating system 2 serves as the heat source for the entire calibration device; after an isothermal cycle is formed in the calibration device, the high temperature heating system 2 is used to supplement heat to the high temperature area of ​​the calibration device.

[0035] The secondary cooling system 3 is used to further cool the cold water part of the calibration device so that its temperature reaches the design requirements of the high-temperature and high-pressure heat exchange system 1.

[0036] The pressure stabilizing system 4 is used to stabilize the pressure of the liquid flow in the high temperature zone so that it is always stable within the expected pressure range.

[0037] High temperature flow control valves are used to regulate liquid flow in the high temperature area of ​​the calibration device.

[0038] The high temperature zone temperature and pressure instrument is installed near the high temperature and high pressure flow meter to be tested, and is used to monitor the medium temperature and pressure near the high temperature and high pressure flow meter 7 to be tested.

[0039] The pressure reducing system 8 is used to quickly reduce the pressure of the liquid medium in the low temperature area so that it meets the use requirements of the standard high temperature and high pressure flow meter 11.

[0040] The low temperature zone temperature and pressure instrument 10 is installed near the standard high temperature and high pressure flow meter 11 to monitor and control the temperature and pressure parameters of the standard high temperature and high pressure flow meter 11 so that it meets the use conditions of the standard high temperature and high pressure flow meter 11.

[0041] The standard high-temperature and high-pressure flowmeter 11 needs to have traceability work carried out at normal temperature and pressure or in hot water conditions below 100°C, and the traceability certificate must be within the validity period.

[0042] The low temperature zone safety valve 12 and the high temperature zone safety valve 14 are used to discharge a certain amount of water or steam when the pressure of the liquid medium in the pipeline exceeds the design threshold (such as 2MPa), so as to ensure the safety of the calibration device during operation.

[0043] The water pump 13 is used to pump the liquid medium in the calibration device, so that the high-temperature liquid medium and the low-temperature liquid medium inside the calibration device move and form a flow rate.

[0044] The exhaust valve system 15 is used to exhaust the gas contained in the liquid medium in the calibration device so that the medium in the calibration device remains in a completely liquid state.

[0045] In this embodiment, the safety valve system 14 in the high temperature zone, the high temperature heating system 2, the exhaust valve system 15, the pressure stabilizing system 4, the high temperature flow regulating valve 5, the high temperature zone temperature and pressure instrument 6 and the high temperature and high pressure flow meter 7 to be tested are connected by a high temperature and high pressure resistant stainless steel pipeline. The inner diameter of the high temperature and high pressure resistant stainless steel pipeline is DN100, and the length is designed according to actual needs.

[0046] More specifically, the connections between the high-temperature and high-pressure resistant stainless steel pipeline and the high-temperature zone safety valve 14, the high-temperature heating system 2, the exhaust valve system 15, the pressure stabilizing system 4, the high-temperature flow regulating valve 5, the high-temperature zone temperature and pressure instrument 6 and the high-temperature and high-pressure flow meter 7 under test are welded or connected by high-temperature and high-pressure sealing to ensure no leakage.

[0047] In this embodiment, the pressure stabilizing system 4 includes a pressure stabilizing valve and a pressure stabilizing container connected in series to ensure the pressure stability of the liquid medium under high temperature and high pressure. The pressure stabilizing valve is a high temperature and high pressure regulating valve that can accurately control the pressure in the pipeline.

[0048] Furthermore, in the present embodiment, the calibration device also includes a high-temperature and high-pressure stainless steel bellows expansion joint, which is connected to the top of the pressure-stabilizing container through a flange. The nominal diameter of the stainless steel bellows expansion joint is DN100, and the maximum expansion amount is 0.3m, which can compensate for the volume change of the liquid medium caused by temperature change and ensure the stability of the pipeline.

[0049] In this embodiment, the high temperature heating system 2 adopts electric heating and is equipped with a temperature control system to accurately control the heating temperature. The heating elements in the high temperature heating system 2 should be evenly distributed to ensure that the liquid medium is heated evenly.

[0050] In this embodiment, the water pump 13 is a high temperature and high pressure centrifugal pump with a flow rate range of 500-1000m 3 / h, with a head of 100m, ensuring stable pumping of liquid media under high temperature and high pressure conditions.

[0051] In this embodiment, the secondary cooling system 3 adopts a water cooling method and is equipped with a cooling circulation pump and a radiator.

[0052] In this embodiment, the low-temperature zone pressure reducing system 8, the low-temperature flow regulating valve 9, the low-temperature zone temperature and pressure instrument 10, the standard high-temperature and high-pressure flow meter 11, the secondary cooling system 3, the low-temperature zone safety valve 12 and the water pump 13 are connected by a high-temperature and high-pressure stainless steel pipeline with an inner diameter of DN100 and a length designed according to actual needs.

[0053] In this embodiment, the standard high temperature and high pressure flow meter 10 has an accuracy level of 0.2% and is used for flow measurement results during the calibration process.

[0054] In this embodiment, the pressure reducing system 8 includes a pressure reducing valve and a pressure reducing container.

[0055] The working principle of the above standard meter method liquid flow calibration device based on the non-isothermal loop is:

[0056] Heating and exhausting stage: First, fill the calibration device with liquid medium, close the secondary cooling system 3, close the high-temperature flow regulating valve 5 and the high-temperature zone safety valve 14, heat the liquid medium to 50°C through the high-temperature heating system 2, then open the high-temperature flow regulating valve 5 and the high-temperature zone safety valve 14, keep the high-temperature heating system 2 in working state, start the water pump 13, make the liquid medium move at a lower flow rate, and gradually discharge the gas contained in the liquid medium through the exhaust valve system 15. It should be noted that the liquid medium can be water or oil. In the heating and exhausting stage, the liquid medium is heated slowly and is below 50°C.

[0057] Temperature and pressure increase stage: After the gas contained in the liquid medium is fully discharged, the liquid medium is kept circulating at a relatively low flow rate, the power of the high-temperature heating system 2 is increased to heat the liquid medium in the high-temperature zone, and the secondary cooling system 3 is turned on to cool the liquid medium in the low-temperature zone, so that the liquid medium in the high-temperature zone gradually reaches the expected high-temperature and high-pressure state, and the liquid medium in the low-temperature zone also gradually reaches the expected low-temperature and low-pressure state.

[0058] Testing phase: After the temperature and pressure of the high-temperature zone and the low-temperature zone reach the preset values, that is, after the non-isothermal medium conditions are formed, the power of the water pump 13 is increased. Driven by the water pump 13, the liquid medium passes through the tested high-temperature and high-pressure flowmeter 7 and the standard high-temperature and high-pressure flowmeter 11 at a set flow rate. At this time, the flow rate, temperature and pressure of the liquid medium also reach a stable state, and the calibration of the tested high-temperature and high-pressure flowmeter 7 can be started.

[0059] Calibration stage: maintain the liquid medium at the set flow, temperature and pressure state, and simultaneously record the measurement values ​​of the high temperature zone temperature and pressure instrument 6, the tested high temperature and high pressure flowmeter 7, the low temperature zone temperature and pressure instrument 10, and the standard high temperature and high pressure flowmeter 11. Take 300s as one measurement, repeat the measurement 6 times, record the average value of the measurement results of each instrument, take the temperature and pressure of the liquid medium in the high temperature zone and the average value of the temperature and pressure of the liquid medium in the low temperature zone as the current calibration medium conditions, and take the i-th flow measurement result Q of the standard high temperature and high pressure flowmeter 11 as the medium condition. si and the i-th flow measurement result Q of the high temperature and high pressure flow meter 7 under test bi The high temperature and high pressure flowmeter 7 under test is calibrated for comparison. The calibration results are expressed in relative indication error and repeatability. The relative indication error of a single time is

[0060]

[0061] The relative indication error of the current flow point is

[0062]

[0063] Here, n is the number of repeated measurements.

[0064] The repeatability of the current flow point is

[0065]

[0066] Temperature and pressure reduction stage: After the test is completed, turn off the high-temperature heating system 2, open the low-temperature zone safety valve 12 and the high-temperature zone safety valve 14 to quickly release the pressure, or do not open the low-temperature zone safety valve 12 and the high-temperature zone safety valve 14, and wait for the liquid medium to cool down naturally until it returns to normal temperature and pressure.

[0067] Example 2

[0068] This embodiment provides an application example of the device described in Embodiment 1, wherein the design target temperature and pressure are 150°C and 2MPa respectively, the pipe diameter is DN100, and the design maximum flow rate is 1000m 3 / h.

[0069] In this embodiment, the high temperature and high pressure heat exchange system uses a high efficiency heat exchanger that can withstand a high temperature of 150°C and a high pressure of 2MPa. The heat exchanger is designed with a hot water side and a cold water side to achieve an isothermal loop.

[0070] Heating and exhausting stage: close the secondary cooling system 3, and close the high-temperature flow regulating valve 5 and the high-temperature zone safety valve 14, start the high-temperature heating system, gradually increase the temperature of the water medium in the high-temperature zone to 50°C, start the water pump to make the water medium move at a lower flow rate, then open the high-temperature flow regulating valve 5 and the high-temperature zone safety valve 14, and gradually discharge the gas contained in the water medium through the exhaust valve system 15 until it is confirmed that there is no gas residual.

[0071] Temperature and pressure increase stage: The water medium in the high temperature zone is heated by increasing the power of the high temperature heating system 2, and the secondary cooling system 3 is turned on to cool the water medium in the low temperature zone, so that the temperature of the water medium in the high temperature zone in the device gradually increases to 150°C, and the pressure gradually increases to 2MPa. At the same time, the water medium in the low temperature zone is cooled to 35°C through the secondary cooling system 3, and the pressure of the water medium in the low temperature zone is 0.5MPa, forming an isothermal loop.

[0072] Test phase: Increase the power of the water pump. Driven by the water pump, the water medium flows at a set flow rate of 500m 3 / h through the tested high temperature and high pressure flowmeter 7 and the standard high temperature and high pressure flowmeter 11 until the temperature and pressure of the water medium in the device reach a stable state and the flow rate stabilizes at 500m 3 / h, the calibration of the high-temperature and high-pressure flowmeter 7 under test can be started.

[0073] Calibration stage: First, keep the flow rate, temperature and pressure of the water medium stable, and simultaneously record the measured values ​​of the high temperature zone temperature and pressure instrument 6, the tested high temperature and high pressure flow meter 7, the low temperature zone temperature and pressure instrument 10, and the standard high temperature and high pressure flow meter 11. Take 300s as one measurement, repeat the measurement 6 times, and record the average value of the measurement results of each instrument. Then, adjust the high temperature flow regulating valve 5 to make the flow rate in the pipeline reach 1000m 3 / h, and keep the flow rate stable, with 300s as one measurement, repeat the measurement 6 times, and record the average value of the measurement results of each instrument. Finally, the average values ​​of the temperature and pressure of the water medium in the high temperature zone and the temperature and pressure of the water medium in the low temperature zone during the calibration process are recorded as the current calibrated medium conditions, and the flow measurement results of the standard high temperature and high pressure flowmeter 11 are compared with the flow measurement results of the high temperature and high pressure flowmeter 7 under test, and the high temperature and high pressure flowmeter 7 under test is calibrated to calculate the relative indication error and repeatability of each flow point measurement.

[0074] Temperature reduction and pressure reduction stage: After the test is completed, the high temperature heating system is turned off, the secondary temperature reduction system 3 is started, and the low temperature zone safety valve 12 and the high temperature zone safety valve 14 are not opened. The temperature of the water medium is reduced to normal temperature by the secondary temperature reduction system 3, and the pressure of the water medium is reduced to normal pressure by not opening the low temperature zone safety valve 12 and the high temperature zone safety valve 14. Close all valves and systems to complete the calibration process.

[0075] For those skilled in the art, various corresponding changes and modifications can be made according to the above technical solutions and concepts, and all of these changes and modifications should be included in the protection scope of the claims of the present invention.

Claims

1. A standard meter method liquid flow calibration device based on an isothermal loop, characterized in that: Including high temperature and high pressure heat exchange system, high temperature heating system, secondary cooling system, pressure stabilizing system, high temperature flow regulating valve, high temperature zone temperature and pressure instrument, tested high temperature and high pressure flow meter, pressure reducing system, low temperature flow regulating valve, low temperature zone temperature and pressure instrument, standard high temperature and high pressure flow meter, low temperature zone safety valve, water pump, high temperature zone safety valve and exhaust valve system; The two sides of the high-temperature and high-pressure heat exchange system are respectively a high-temperature zone and a low-temperature zone; in the low-temperature zone, the pressure reduction system, the low-temperature flow regulating valve, the low-temperature zone temperature and pressure instrument, the standard high-temperature and high-pressure flow meter, the secondary cooling system, the low-temperature zone safety valve and the water pump are connected in sequence; in the high-temperature zone, the high-temperature zone safety valve, the high-temperature heating system, the exhaust valve system, the pressure stabilizing system, the high-temperature flow regulating valve, the high-temperature zone temperature and pressure instrument and the tested high-temperature and high-pressure flow meter are connected in sequence; the high-temperature and high-pressure heat exchange system at least includes a cold medium heating channel and a hot medium cooling channel; the outlet of the water pump is connected to the inlet of the cold medium heating channel of the high-temperature and high-pressure heat exchange system, The inlet of the high-temperature zone safety valve is connected to the outlet of the cold medium heating channel of the high-temperature and high-pressure heat exchange system, the outlet of the tested high-temperature and high-pressure flowmeter is connected to the inlet of the hot medium cooling channel of the high-temperature and high-pressure heat exchange system, and the inlet of the pressure reducing system is connected to the outlet of the hot medium cooling channel of the high-temperature and high-pressure heat exchange system; the cold medium enters the high-temperature and high-pressure heat exchange system from the inlet of the cold medium heating channel, becomes the hot medium through heat exchange, and is discharged from the outlet of the cold medium heating channel into the high-temperature zone; the hot medium enters the high-temperature and high-pressure heat exchange system from the inlet of the hot medium cooling channel, becomes the cold medium through heat exchange, and is discharged from the outlet of the hot medium cooling channel into the low-temperature zone.

2. The standard meter method liquid flow calibration device based on the non-isothermal loop according to claim 1 is characterized in that: The safety valve system in the high temperature zone, the high temperature heating system, the exhaust valve system, the pressure stabilizing system, the high temperature flow regulating valve, the temperature and pressure instrument in the high temperature zone and the high temperature and high pressure flow meter under test are connected by high temperature and high pressure resistant stainless steel pipes.

3. The standard meter method liquid flow calibration device based on the non-isothermal loop according to claim 2 is characterized in that: The connections between each high-temperature and high-pressure resistant stainless steel pipeline and the high-temperature area safety valve, high-temperature heating system, exhaust valve system, pressure stabilizing system, high-temperature flow regulating valve, high-temperature area temperature and pressure instrument and the high-temperature and high-pressure flow meter under inspection are welded or connected by high-temperature and high-pressure sealing to ensure no leakage.

4. The standard meter method liquid flow calibration device based on the non-isothermal loop according to claim 1 is characterized in that: The pressure stabilizing system comprises a pressure stabilizing valve and a pressure stabilizing container which are connected in series.

5. The standard meter method liquid flow calibration device based on the non-isothermal loop according to claim 4 is characterized in that: It also includes a high-temperature and high-pressure stainless steel bellows expansion joint, which is connected to the top of the pressure-stabilizing container through a flange to compensate for the volume change of the liquid medium caused by temperature change.

6. The standard meter method liquid flow calibration device based on the non-isothermal loop according to claim 1 is characterized in that: The high temperature heating system adopts an electric heating method or a heat exchange method, and is equipped with a temperature control system for accurately controlling the heating temperature.

7. The standard meter method liquid flow calibration device based on the non-isothermal loop according to claim 1 is characterized in that: The water pump meets the design requirements of high pressure resistance, the flow range should cover the design value of the high temperature and high pressure heat exchange system, and the head range should be higher than the overall pressure loss of the calibration device.

8. The standard meter method liquid flow calibration device based on the non-isothermal loop according to claim 1 is characterized in that: The secondary cooling system adopts water cooling, including a cooling circulation pump and a radiator.

9. The standard meter method liquid flow calibration device based on the non-isothermal loop according to claim 1 is characterized in that: The low temperature zone's pressure reducing system, low temperature flow regulating valve, low temperature zone temperature and pressure instrument, standard high temperature and high pressure flow meter, secondary cooling system, low temperature zone safety valve and water pump are connected by high temperature and high pressure resistant stainless steel pipes.

10. A method for calibrating liquid flow rate using the standard meter method based on a non-isothermal loop as claimed in any one of claims 1 to 9, characterized in that: The specific process is as follows: Heating and exhausting stage: First, fill the calibration device with liquid medium, close the secondary cooling system, close the high-temperature flow regulating valve and the high-temperature zone safety valve, heat the liquid medium to the set first temperature through the high-temperature heating system, then open the high-temperature flow regulating valve and the high-temperature zone safety valve, keep the high-temperature heating system in working state, start the water pump, make the liquid medium move at a lower flow rate, and gradually exhaust the gas contained in the liquid medium through the exhaust valve system; In the temperature rising exhaust stage, the liquid medium is slowly heated and is below the first temperature; Temperature and pressure increase stage: After the gas contained in the liquid medium is fully discharged, the liquid medium is kept circulating at a relatively low flow rate, the power of the high-temperature heating system is increased to heat the liquid medium in the high-temperature zone, and the secondary cooling system is turned on to cool the liquid medium in the low-temperature zone, so that the liquid medium in the high-temperature zone gradually reaches the expected high-temperature and high-pressure state, and the liquid medium in the low-temperature zone also gradually reaches the expected low-temperature and low-pressure state; Test phase: After the temperature and pressure of the high temperature zone and the low temperature zone reach the preset values, that is, after the non-isothermal medium conditions are formed, the power of the water pump is increased. Driven by the water pump, the liquid medium passes through the high temperature and high pressure flowmeter to be tested and the standard high temperature and high pressure flowmeter at the set flow rate. At this time, the flow rate, temperature and pressure of the liquid medium also reach a stable state, and the calibration of the high temperature and high pressure flowmeter to be tested can be started; Calibration phase: maintain the liquid medium at the set flow rate, temperature and pressure state, take the set time as one measurement, repeat the measurement n times, and simultaneously record the measurement values ​​of the high temperature zone temperature and pressure instrument, the tested high temperature and high pressure flowmeter, the low temperature zone temperature and pressure instrument and the standard high temperature and high pressure flowmeter. The average value of the temperature and pressure of the liquid medium in the high temperature zone and the temperature and pressure of the liquid medium in the low temperature zone are used as the current calibration medium conditions, and the flow measurement result Q of the standard high temperature and high pressure flowmeter for the i-th time is used as the calibration medium condition. si and the i-th flow measurement result Q of the high temperature and high pressure flowmeter under test bi For comparison, the high temperature and high pressure flow meter under test is calibrated; the calibration result is expressed in relative indication error and repeatability, and the single relative indication error is: The relative indication error of the current flow point is: Where n is the number of repeated measurements; The repeatability of the current flow point is: Cooling and pressure reduction stage: After the test is completed, turn off the high-temperature heating system, open the low-temperature zone safety valve and the high-temperature zone safety valve to quickly release the pressure, or do not open the low-temperature zone safety valve and the high-temperature zone safety valve, and wait for the liquid medium to cool down naturally until it returns to normal temperature and pressure.

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