A switchable gas detection device and method for gas-liquid two-phase flow pipelines

Abstract

The application discloses a switchable gas detection device and method for a gas-liquid two-phase flow pipeline, which comprises a main pipeline, a container, a first baffle plate, a first bypass pipeline, a second bypass pipeline, a first valve, a second valve, a flowmeter and a water supplement valve. The container is divided into a first cavity and a second cavity by the first baffle plate, and a gap is left between the first baffle plate and the inner bottom wall of the container. The main pipeline is connected with the first cavity through the first bypass pipeline, and the second cavity is connected with the main pipeline through the second bypass pipeline. The first valve is arranged on the first bypass pipeline, the second valve and the flowmeter are arranged on the second bypass pipeline, and the water supplement valve is arranged on the top of the container and connected with the container. The application realizes the natural separation of gas and fluid based on the density difference between gas and liquid, does not need to additionally configure a separation device, has the advantages of simple structure and low cost, can analyze the composition of the separated gas, and can directly record the volume of the gas and the volume of the fluid in unit time after separation. The volume of the gas is divided by the volume of the fluid, so that the proportion of the gas can be calculated.

Description

Technical Field

[0001] This invention relates to the field of fluid measurement and safety monitoring technology, and in particular to a switchable gas detection device and method for gas-liquid two-phase flow pipelines. Background Technology

[0002] The brine in the delivery pipeline contains a small amount of gas. The brine is a two-phase flow of gas and liquid, so it is necessary to effectively separate the gas in the brine and extract pure gas in order to calculate the content and composition of the gas in the brine.

[0003] Taking the application scenario of gas injection and brine discharge in a natural gas salt cavern storage facility as an example: During the gas injection and brine discharge process in a natural gas salt cavern storage facility, underground brine is forced to the surface and sent to the brine collection pool through the brine discharge pipeline. The discharged brine may contain natural gas, threatening the safety and reliability of gas injection and brine discharge. Therefore, it is necessary to detect the methane content in the brine during the brine discharge process to provide a basis for timely adjustments to production operations.

[0004] Current technologies for detecting entrained gases in pipelines only involve sampling the gas at the pipeline's sampling port. This not only fails to measure the gas content in the pipeline's brine but also makes it difficult to accurately measure the methane content in the gas due to the easy mixing of air during sampling. To achieve this gas detection objective, complex and expensive separation equipment often needs to be installed in a bypass, making it difficult to achieve simple, rapid, online, and continuous detection without interrupting the main process. Summary of the Invention

[0005] The main objective of this invention is to provide a switchable gas detection device and method for gas-liquid two-phase flow pipelines. Based on the density difference between gas and liquid, it achieves natural separation of natural gas and fluid without the need for additional separation devices. It has a simple structure, low cost, and can intuitively record the volume of gas and fluid per unit time after separation. The proportion of gas can be calculated by dividing the volume of gas by the volume of fluid.

[0006] To achieve the above objectives, the technical solution adopted by the present invention is as follows: A switchable gas detection device for a gas-liquid two-phase flow pipeline includes a main pipeline and a container. The container is divided into a first cavity and a second cavity by a first baffle plate. A gap is left between the first baffle plate and the bottom wall of the container. The main pipeline is connected to the first cavity through a first bypass pipeline, and the second cavity is connected to the main pipeline through a second bypass pipeline. A first valve is installed on the first bypass pipeline, and a second valve and a flow meter are installed on the second bypass pipeline. A water supply valve is installed at the top of the container, and the outlet of the water supply valve is connected to the container. A volume measuring device is installed in the first cavity.

[0007] Furthermore, a thermometer and a pressure gauge are fixed to the top of the container, and the detection ends of the thermometer and pressure gauge are located at the top of the first cavity.

[0008] Furthermore, the outlet of the first bypass pipe extends into the bottom of the first cavity.

[0009] Furthermore, the volume measuring device is a ruler.

[0010] Furthermore, a third valve and a fourth valve are installed on the main pipeline, and the third valve and the fourth valve are located between the first bypass pipeline and the second bypass pipeline.

[0011] Furthermore, a first exhaust valve is provided on the top of the container, and the air inlet of the first exhaust valve is connected to the top of the container.

[0012] Furthermore, a second baffle is fixed at the bottom of the first cavity, the top of the second baffle being higher than the bottom of the first baffle and lower than the volume measuring device.

[0013] The present invention also discloses a gas detection method for gas-liquid two-phase flow, the first step being: closing the first valve and the second valve, opening the first exhaust valve and the water supply valve, replenishing water to the container through the water supply valve, and purging the air in the first bypass pipe and the container; Step 2: After water comes out of the first vent valve, close the first vent valve and the water supply valve to fill the container and the first bypass pipe connected to it with water. Step 3: First open the second valve, then open the first valve to allow the fluid to enter the container. At this time, the gas rises and the liquid falls, achieving gas and liquid separation. Step 4: Close the third and fourth valves to allow all subsequent fluid to flow through the container; Step 5: Record the gas volume in the first chamber per unit time and the total volume of liquid discharged from the container per unit time, and calculate the gas-to-fluid ratio. Step 6: Connect the exhaust port of the first exhaust valve to the gas detector or sampling bag, open the first exhaust valve to allow the gas to enter the gas detector or sampling bag, and the gas composition can be detected.

[0014] Step 7: Deactivate the gas detection device, open the third and fourth valves, and then close the first and second valves in sequence to complete the switching.

[0015] Furthermore, the specific calculation method for step five is as follows: When the gas-liquid interface is seen on the container scale, record the time K0 and the gas volume scale value C0 at this time, and simultaneously record the time K0 and the cumulative flow value M0 of the flow meter. When the gas-liquid interface continues to drop to C1, record the time K1 and the cumulative flow value M1 of the flow meter. According to the calculation formula φ=(C1-C0) / (M1-M0), the gas content φ in the fluid during K0-K1 can be calculated.

[0016] Furthermore, the specific calculation method for step five is as follows: When the gas-liquid interface is observed on the scale, record the gas volume scale value V1 displayed on the scale at this time, and simultaneously record the time t1, the pressure P1 of the pressure gauge, the temperature T1 of the thermometer, and the cumulative flow value Q1 of the flow meter. Based on the ideal gas law, calculate the gas volume under standard conditions at time t1 using the formula for calculating gas volume. When the gas-liquid interface continues to descend to the scale value V2, record the time t2, the pressure P2 of the pressure gauge, the temperature T2 of the thermometer, and the cumulative flow value Q2 of the flow meter. At this time, the gas volume under standard conditions is recorded. Formula for calculating the gas content φ in a fluid: The gas content in the fluid during the period t1-t2 can be calculated.

[0017] Compared with the prior art, the present invention has the following beneficial effects: This invention achieves natural separation of gas and fluid based on the density difference between gas and liquid, without the need for additional separation devices. It has a simple structure and low cost. It can perform component analysis on the separated gas and can intuitively record the volume of gas and fluid per unit time after separation. The proportion of gas can be calculated by dividing the volume of gas by the volume of fluid.

[0018] This invention uses a second baffle to deflect, slow down, and settle the fluid entering the container, providing a stable separation space for the gas-liquid two-phase flow. This allows the small amount of gas entrained in the fluid to be fully gathered, floated, and separated, preventing tiny bubbles from flowing away directly with the fluid. This effectively separates and traps the gas.

[0019] This invention combines volume measurement, temperature and pressure monitoring, and flow measurement, and uses the ideal gas law to convert the working condition volume into the standard state volume, which can accurately calculate the volume ratio of gas in the fluid.

[0020] This invention adopts a parallel switchable structure of main pipeline and detection branch. Under normal conditions, the detection branch is closed, and the fluid is transported normally only in the main pipeline, which does not affect the continuous operation of gas injection and brine discharge. When detection is required, the detection mode can be put into operation simply by switching the valve. There is no need to stop the flow or modify the main pipeline. This solves the problem that traditional detection methods require interruption of production and affect the continuity of brine discharge operations in salt cavern gas storage, and realizes safe and efficient online detection. Attached Figure Description

[0021] Figure 1 This is a schematic diagram of the overall structure of a switchable gas detection device for a gas-liquid two-phase flow pipeline according to the present invention.

[0022] Figure 2 This is a top view schematic diagram of a switchable gas detection device for a gas-liquid two-phase flow pipeline according to the present invention.

[0023] In the diagram: 1. Container; 2. Third valve; 3. Fourth valve; 4. First valve; 5. Thermometer; 6. First vent valve; 7. Water supply valve; 8. Flow meter; 9. Second valve; 10. Volume measuring device; 11. First baffle plate; 12. Main pipeline; 13. First bypass pipeline; 14. Second bypass pipeline; 15. Second cavity; 16. First cavity; 17. Pressure gauge; 18. Second baffle plate. Detailed Implementation

[0024] The present invention will now be described in detail with reference to the accompanying drawings.

[0025] In the description of this invention, it should be understood that the terms "center," "longitudinal," "lateral," "length," "width," "thickness," "upper," "lower," "front," "rear," "left," "right," "vertical," "horizontal," "top," "bottom," "inner," "outer," "clockwise," "counterclockwise," "axial," "radial," and "circumferential" indicate the orientation or positional relationship based on the orientation or positional relationship shown in the accompanying drawings. They are used only for the convenience of describing this invention and simplifying the description, and do not indicate or imply that the device or element referred to must have a specific orientation, or be constructed and operated in a specific orientation. Therefore, they should not be construed as limitations on this invention.

[0026] Furthermore, the terms "first" and "second" are used for descriptive purposes only and should not be construed as indicating or implying relative importance or implicitly specifying the number of technical features indicated. Thus, a feature defined as "first" or "second" may explicitly or implicitly include at least one of that feature. In the description of this invention, "a plurality of" means at least two, such as two, three, etc., unless otherwise explicitly specified.

[0027] In this invention, unless otherwise explicitly specified and limited, the terms "installation," "connection," "linking," and "fixing," etc., should be interpreted broadly. For example, they can refer to a fixed connection, a detachable connection, or an integral part; they can refer to a mechanical connection or an electrical connection; they can refer to a direct connection or an indirect connection through an intermediate medium; they can refer to the internal communication of two components or the interaction between two components, unless otherwise explicitly limited. Those skilled in the art can understand the specific meaning of the above terms in this invention according to the specific circumstances. Example 1

[0028] like Figure 1-2 As shown, a switchable gas detection device for a gas-liquid two-phase flow pipeline includes a main pipeline 12 and a container 1. The container 1 is divided into a first cavity 16 and a second cavity 15 by a first baffle 11. A gap is left between the first baffle 11 and the bottom wall of the container 1, allowing fluid communication between the first cavity 16 and the second cavity 15 at the bottom. The main pipeline 12 is connected to the first cavity 16 via a first bypass pipeline 13, and the second cavity 15 is connected to the main pipeline 12 via a second bypass pipeline 14, thus forming an independently switchable detection branch outside the main pipeline 12. A first valve 4 is provided on the first bypass pipeline 13 to control the flow of the fluid to be tested into the first cavity 16. A second valve 4 is provided on the second bypass pipeline 14. The second valve 9 is used to control the backflow interruption of the detection branch, and the flow meter 8 is used to measure the cumulative flow of fluid flowing through the detection branch. The top of the container 1 is equipped with a water supply valve 7, the outlet of which is connected to the container 1. Liquid can be injected into the container 1 until it is full, so as to completely discharge the gas in the container 1. The first cavity 16 is equipped with a volume measuring device 10, which is a scale used to directly read the volume value of the gas collected in the first cavity 16. This device is arranged in parallel with the main road and the bypass, realizing the independent switching between the normal pipeline transportation condition and the gas detection condition. Without interrupting the main fluid transportation, it provides a structural basis for the online detection of gas content in gas-liquid two-phase flow.

[0029] In this embodiment, the device is normally in the normal conveying mode, and the gas-liquid two-phase flow is continuously and stably conveyed in the main pipeline 12. At this time, both the first valve 4 and the second valve 9 are closed, and the detection branch is isolated from the main pipeline 12. When it is necessary to detect the gas content in the gas-liquid two-phase flow, the device can be switched to the detection mode by opening the first valve 4 and the second valve 9, so that the fluid to be tested flows into the container 1 in a directional manner to complete the gas-liquid separation.

[0030] Specifically, after the gas-liquid two-phase flow enters the first cavity 16 from the bottom through the first bypass pipe 13, the gas rises and accumulates in the sealed space at the top of the first cavity 16 due to the density difference between the gas and the liquid, while the liquid sinks under the action of gravity. As the fluid continues to flow in, the gas accumulated at the top of the first cavity 16 continues to accumulate, and the gas-liquid interface gradually moves downward to form a clear and stable stratified interface. The liquid that settles to the bottom flows into the second cavity 15 through the flow gap between the first baffle 11 and the bottom wall of the container 1, and then flows back to the main pipe 12 along the second bypass pipe 14 and the flow meter 8. The separated gas is trapped at the top of the first cavity 16 and cannot flow out with the liquid phase, thereby achieving continuous and stable separation of the gas and liquid phases.

[0031] Under stable gas-liquid separation conditions, the gas volume, corresponding time, pressure, temperature, and cumulative flow of the flow meter are recorded at different times. The gas volume under operating conditions is converted to the standard state volume by combining the ideal gas law. Then, the proportion of gas in the fluid is calculated by the ratio of the gas volume increment to the total fluid flow increment.

[0032] A thermometer 5 and a pressure gauge 17 are fixed on the top of container 1. The detection ends of the thermometer 5 and the pressure gauge 17 are located at the top of the first cavity 16. Since the density of gas is much smaller than that of liquid, the separated gas will concentrate in the upper space of the first cavity 16. Therefore, the thermometer 5 and the pressure gauge 17 can detect the temperature and pressure parameters of the collected gas, avoiding measurement deviations caused by the detection ends being immersed in the liquid phase or in the gas-liquid mixing zone, and ensuring the accuracy of the gas content calculation results.

[0033] The outlet of the first bypass pipe 13 extends into the bottom of the first cavity 16. A second baffle plate 18 is fixed at the bottom of the first cavity 16. The top of the second baffle plate 18 is higher than the bottom of the first baffle plate 11. The second baffle plate 18 can form a flow-blocking structure at the bottom of the first cavity 16. The gas-liquid two-phase flow entering from the first bypass pipe 13 will first be blocked and buffered by the second baffle plate 18, reducing the medium flow rate and playing a baffle role. It can efficiently separate gas and liquid, creating a long-term, low-flow-rate, large-space sedimentation environment, which is conducive to the aggregation and rise of microbubbles, thereby achieving the separation of small amounts of gas, so that the device can detect trace amounts of gas.

[0034] The main pipeline 12 is equipped with a third valve 2 and a fourth valve 3, which are located between the first bypass pipeline 13 and the second bypass pipeline 14. Under the detection condition, closing the third valve 2 and the fourth valve 3 can completely block the direct flow path of the main pipeline 12, so that all the gas-liquid two-phase flow to be tested in the main pipeline must flow through the first bypass pipeline 13, container 1, and second bypass pipeline 14 in sequence before returning to the main pipeline 12, so as to realize the full fluid flow through the detection branch.

[0035] The container 1 is equipped with a first exhaust valve 6 at the top. The air inlet of the first exhaust valve 6 is located at the top of the container 1. The first exhaust valve 6 works in conjunction with the water supply valve 7. The liquid injected into the container 1 will fill the container 1 and gradually fill the first bypass pipe 13. This will drive the air originally present in this pipe and the container 1 upward and discharge it through the first exhaust valve 6, eliminating the systematic error of the initial residual air on the detection results. After the gas volume measurement is completed, the first cavity 16 will accumulate high-purity separated gas. Opening the first exhaust valve 6 can use the pressure of the medium inside the container to export the pure gas, which is convenient for connecting an external gas detector or sampling bag to perform gas composition analysis and sample collection, and realize the detection of gas properties. Example 2

[0036] The present invention also discloses a gas detection method for gas-liquid two-phase flow. Step 1: By closing the first valve 4 and the second valve 9, the connection between container 1 and the main pipeline is cut off. At the same time, the first exhaust valve 6 and the water supply valve 7 are opened. Water is injected into container 1 using the water supply valve 7. The water flow completely removes the original air inside the first bypass pipeline 13 and container 1, eliminating the initial air interference for subsequent detection. Step 2: When it is observed that the first vent valve 6 is emitting water stably and there are no air bubbles, it is determined that the air in the container 1 and the first bypass pipe 13 has been exhausted. Then, the first vent valve 6 and the water supply valve 7 are closed to make the container 1 and the connected bypass pipe completely filled with water, forming a closed and full water initial state with no residual air. Step 3: Operate in the order of opening the second valve 9 first and then the first valve 4 to allow the gas-liquid two-phase flow in the main pipeline to smoothly enter the container 1. Utilize the density difference between gas and liquid to make the gas gather upward and the liquid sink downward, achieving natural separation of the gas and liquid phases in the container. After the gas gathers, the water that originally occupied the space will be squeezed out and discharged through the second bypass pipeline 14. Step 4: By closing the third valve 2 and the fourth valve 3 on the main pipeline, the direct flow channel of the main pipeline is cut off, forcing all subsequent test fluids to flow through container 1, ensuring that the test sample is a full-flow fluid, and improving the representativeness and accuracy of the gas content detection results; Step 5: Under stable gas-liquid separation, record the gas volume, corresponding time, pressure, temperature and cumulative flow of the flow meter at different times. Combine the ideal gas law to convert the gas volume under working conditions to the standard state volume. Then, calculate the gas ratio in the fluid by the ratio of the gas volume increment to the total fluid flow increment. Step 6: Connect a gas detector or sampling bag to the exhaust port of the first exhaust valve 6, open the first exhaust valve 6, and use the internal pressure of the container to make the separated pure gas flow into the detection equipment, thereby completing the detection and analysis of gas components.

[0037] Step 7: After the test is completed, first open the third valve 2 and the fourth valve 3 to restore the normal flow of the main pipeline, and then close the first valve 4 and the second valve 9 in sequence to cut off the test branch, thus completing the switch between the test mode and the normal transport mode without affecting the continuous operation of the pipeline system.

[0038] The specific calculation method for step five is as follows: When the gas-liquid interface is seen on the container scale, record the time K0 and the gas volume scale value C0 at this time, and simultaneously record the time K0 and the cumulative flow value M0 of the flow meter. When the gas-liquid interface continues to drop to C1, record the time K1 and the cumulative flow value M1 of the flow meter 8. According to the calculation formula φ=(C1-C0) / (M1-M0), the gas content φ in the fluid during K0-K1 can be calculated. Example 3

[0039] Unlike Example 2, the specific calculation method for step five is as follows: When the gas-liquid interface is observed on the scale, record the gas volume scale value V1 displayed on the scale at this time, and simultaneously record the time t1, the pressure P1 of pressure gauge 17, the temperature T1 of thermometer 5, and the cumulative flow value Q1 of flow meter. According to the ideal gas law, calculate the standard state at t1 (usually referring to 0℃, i.e., T). n =273.15K, pressure P n Formula for calculating gas volume at 101.325 kPa When the gas-liquid interface continues to descend to the scale value V2, record the time t2, the pressure P2 of the pressure gauge, the temperature T2 of the thermometer, and the cumulative flow value Q2 of the flow meter. At this time, the gas volume under standard conditions is recorded. Formula for calculating the gas content φ in a fluid: The gas content in the fluid during the period t1-t2 can be calculated.

[0040] P1 and P2 are absolute pressures, and T2 and T1 are Kelvin temperatures.

[0041] Working principle: Under normal conditions, the first valve 4 and the second valve 9 are closed, isolating the detection branch from the main pipeline 12. The gas-liquid two-phase flow is only transported normally within the main pipeline 12. During detection, the first valve 4 and the second valve 9 are opened, and the third valve 2 and the fourth valve 3 on the main pipeline 12 can be closed, allowing the full flow of fluid to pass through the detection branch. The gas-liquid two-phase flow enters the bottom of the first cavity 16 of the container 1 through the first bypass pipeline 13. After being buffered and slowed by the second baffle 18, natural separation is achieved by utilizing the density difference between gas and liquid. The gas rises and accumulates at the top of the first cavity 16, while the liquid flows into the second cavity 15 through the gap between the first baffle 11 and the inner bottom wall of the container 1, and returns through the second bypass pipeline 14. The gas flows to the main pipeline 12. Before testing, water is injected through the water supply valve 7, and the initial air in container 1 and the first bypass pipeline 13 is purged by the first exhaust valve 6 to eliminate errors. During the testing process, the volume of the accumulated gas is read by the volume measuring device 10. Combined with the gas temperature and pressure parameters collected by the thermometer 5 and the pressure gauge 17 and the cumulative flow of the flow meter 8, the gas volume under working conditions is converted to the standard state volume using the ideal gas law. Then, the gas proportion is calculated by the ratio of the gas volume increment to the total fluid flow increment. After the test is completed, the first exhaust valve 6 can be opened to export pure gas for component analysis. Finally, the valve is switched to restore the normal transport of the main pipeline 12, and the continuous transport of the pipeline fluid is not interrupted throughout the process.

[0042] The above embodiments are only for illustrating the technical concept and features of the present invention, and are intended to enable those skilled in the art to understand the content of the present invention and implement it accordingly. They should not be construed as limiting the scope of protection of the present invention. All equivalent transformations or modifications made in accordance with the spirit and essence of the present invention should be covered within the scope of protection of the present invention.

Claims

1. A switchable gas detection device for a gas-liquid two-phase flow pipeline, comprising a main pipeline (12), characterized in that: It also includes a container (1), which is divided into a first cavity (16) and a second cavity (15) by a first baffle (11). There is a gap between the first baffle (11) and the bottom wall of the container (1). The main pipeline (12) is connected to the first cavity (16) by a first bypass pipeline (13). The second cavity (15) is connected to the main pipeline (12) by a second bypass pipeline (14). A first valve (4) is provided on the first bypass pipeline (13). A second valve (9) and a flow meter (8) are provided on the second bypass pipeline (14). A water supply valve (7) is provided on the top of the container (1). The outlet of the water supply valve (7) is connected to the container (1). A volume measuring device (10) is provided in the first cavity (16).

2. The switchable gas detection device for a gas-liquid two-phase flow pipeline according to claim 1, characterized in that: A thermometer (5) and a pressure gauge (17) are fixed on the top of the container (1), and the detection ends of the thermometer (5) and the pressure gauge (17) are located at the top of the first cavity (16).

3. A switchable gas detection device for a gas-liquid two-phase flow pipeline according to claim 2, characterized in that: The outlet of the first bypass pipe (13) extends into the bottom of the first cavity (16).

4. A switchable gas detection device for a gas-liquid two-phase flow pipeline according to claim 2, characterized in that: The volume measuring device (10) is a ruler.

5. A switchable gas detection device for a gas-liquid two-phase flow pipeline according to claim 4, characterized in that: The main pipeline (12) is equipped with a third valve (2) and a fourth valve (3), which are located between the first bypass pipeline (13) and the second bypass pipeline (14).

6. A switchable gas detection device for a gas-liquid two-phase flow pipeline according to claim 5, characterized in that: The container (1) is provided with a first exhaust valve (6) at the top, and the air inlet of the first exhaust valve (6) is connected to the top of the container (1).

7. A switchable gas detection device for a gas-liquid two-phase flow pipeline according to claim 6, characterized in that: A second baffle plate (18) is fixed at the bottom of the first cavity (16). The top of the second baffle plate (18) is higher than the bottom of the first baffle plate (11) and lower than the volume measuring device (10).

8. A gas detection method for gas-liquid two-phase flow, based on the switchable gas detection device for gas-liquid two-phase flow pipeline as described in claim 7, characterized in that: Step 1: Close the first valve (4) and the second valve (9), open the first exhaust valve (6) and the water supply valve (7), and replenish water to the container (1) through the water supply valve (7) to drain the air from the first bypass pipe (13) and the container (1); Step 2: After water comes out of the first vent valve (6), close the first vent valve (6) and the water supply valve (7) to fill the container (1) and the first bypass pipe (13) connected to it with water; Step 3: First open the second valve (9), then open the first valve (4) to allow the fluid to enter the container (1). At this time, the gas rises and the liquid falls, thus achieving gas and liquid separation. Step 4: Close the third valve (2) and the fourth valve (3) to allow all subsequent fluid to flow through the container (1); Step 5: Record the gas volume in the first cavity (16) per unit time and the total volume of liquid discharged from container (1) per unit time, and calculate the proportion of gas to fluid. Step 6: Connect the exhaust port of the first exhaust valve (6) to the gas detector or sampling bag, open the first exhaust valve (6) to allow the gas to enter the gas detector or sampling bag, and the gas composition can be detected. Step 7: Discontinue the gas detection device, open the third valve (2) and the fourth valve (3), and close the first valve (4) and the second valve (9) in sequence to complete the switching.

9. A gas detection method for gas-liquid two-phase flow according to claim 8, characterized in that: The specific calculation method for step five is as follows: When the gas-liquid interface is seen on the scale of the container, record the time K0 and the gas volume scale value C0 at this time, and at the same time record the time K0 and the cumulative flow value M0 of the flow meter (8). When the gas-liquid interface continues to drop to C1, record the time K1 and the cumulative flow value M1 of the flow meter (8). According to the calculation formula φ=(C1-C0) / (M1-M0), the gas content φ in the fluid during K0-K1 can be calculated.

10. A gas detection method for gas-liquid two-phase flow according to claim 8, characterized in that: Step 5 is calculated as follows: When the gas-liquid interface is seen on the scale, record the gas volume scale value V1 displayed on the scale at this time, and at the same time record the time t1, the pressure P1 of the pressure gauge (17), the temperature T1 of the thermometer (5), and the cumulative flow value Q1 of the flow meter. According to the ideal gas law, calculate the gas volume under standard conditions at t1 using the formula. When the gas-liquid interface continues to descend to the scale value V2, record the time t2, the pressure P2 of the pressure gauge, the temperature T2 of the thermometer, and the cumulative flow value Q2 of the flow meter. At this time, the gas volume under standard conditions is recorded. Formula for calculating the gas content φ in a fluid: The gas content in the fluid during the period t1-t2 can be calculated.

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