Positive displacement gas-liquid two-phase flowmeter and measurement method thereof

Abstract

The present invention relates to the field of gas-liquid metering technology, and is a volumetric gas-liquid two-phase flowmeter, comprising a first volumetric flowmeter, a second volumetric flowmeter, a first pressure transmitter, a second pressure transmitter and a differential pressure tube. The present invention has a reasonable and compact structure and is easy to use. During use, the volumetric flowmeter is used for measurement, and the results are more accurate. The pressure transmitter can measure a wide range of media, such as oil, water, etc., and has a certain anti-corrosion ability; high accuracy and high stability; the differential pressure tube creates a corresponding pressure difference between the front and rear ends of the differential pressure tube through other methods such as diameter reduction, and finally calculates the volume occupied by the liquid and measures the volume of the gas and liquid. During the metering process, there is no need to separate the gas-liquid two-phase mixed fluid, which greatly reduces the volume and cost of the equipment. Continuous metering can also be performed, and the structure sealed with the outside is safer and more reliable, with the characteristics of safety, labor saving, simplicity and high efficiency.

Description

Technical Field

[0001] The invention relates to the technical field of gas-liquid metering, in particular to a volumetric gas-liquid two-phase flow meter and a measurement method thereof. Background Art

[0002] Currently, most gas-liquid two-phase flowmeters use gravity settling to separate and measure gas and liquid, often referred to as the GLCC method. This separation method often requires larger containers for separation. Other methods use imaging techniques such as X-rays and then calculate the gas-liquid ratio using graphics processing, but this is costly. Existing differential pressure flowmeters cannot measure the flow of gas-liquid mixtures. Summary of the Invention

[0003] The present invention provides a volumetric gas-liquid two-phase flowmeter and a measurement method thereof, which overcome the deficiencies of the above-mentioned prior art and can effectively solve the problems that the existing gas-liquid two-phase flowmeter requires separation and measurement of gas and liquid, imaging processing by methods such as radiation is costly, and differential pressure flowmeters cannot detect the flow of gas-liquid two-phase mixed fluids.

[0004] One of the technical solutions of the present invention is achieved through the following measures: a volumetric gas-liquid two-phase flowmeter, including a first volumetric flowmeter, a second volumetric flowmeter, a first pressure transmitter, a second pressure transmitter and a differential pressure tube, the first volumetric flowmeter, the differential pressure tube and the second volumetric flowmeter are fixed together in sequence, the first pressure transmitter is installed at the left end of the first volumetric flowmeter, and the second pressure transmitter is installed at the left end of the second volumetric flowmeter.

[0005] The following is a further optimization and / or improvement of one of the above-mentioned technical solutions:

[0006] The inner diameter of the differential pressure tube may be in the shape of a funnel with a larger left portion and a smaller right portion, and the inner diameter of the right portion of the differential pressure tube may be smaller than the inner diameter of the left end of the second positive displacement flowmeter.

[0007] The above may also include a temperature transmitter, and the temperature transmitter is installed at the right end of the second positive displacement flowmeter.

[0008] The left end of the first positive displacement flowmeter corresponding to the left side of the first pressure transmitter may be provided with a mounting flange, and the right end of the second positive displacement flowmeter corresponding to the right side of the second pressure transmitter may be provided with a mounting flange.

[0009] The second technical solution of the present invention is achieved by the following measures: a measurement method using the above-mentioned volumetric gas-liquid two-phase flowmeter comprises the following steps:

[0010] In the first step, the first pressure transmitter measures the pressure P1 of the gas flowing through the measured metering pipeline during a metering time;

[0011] In the second step, the first positive displacement flowmeter measures the volume C1 of the gas-liquid two-phase mixed fluid flowing through the measured metering pipeline within a certain metering time;

[0012] In the third step, the second pressure transmitter measures the pressure P2 of the gas flowing through the differential pressure tube in the measured metering pipeline within a metering time;

[0013] In the fourth step, the second positive displacement flowmeter measures the volume C2 of the gas-liquid two-phase mixed fluid flowing through the differential pressure tube in the measured metering pipeline within a metering time;

[0014] The gas volume and liquid volume in the measured metering pipeline during a certain metering time can be calculated using the following formula:

[0015] (1) According to Boyle's law: for a certain mass of a gas, when the temperature remains constant, the pressure P is inversely proportional to the volume V, that is, P1V1=P2V2;

[0016] (2) The molecular weights of the gas and liquid flowing through the first and second positive displacement flowmeters during a period of measurement time are the same, and the volume ratio of the gas flowing through the first and second positive displacement flowmeters is V1 / V2=P2 / P1;

[0017] (3) The fluid volume measured by the first and second positive displacement flow meters is C1-C2=V1-V2;

[0018] (4) The values ​​of gas volumes V1 and V2 can be derived and calculated using formulas (1), (2), and (3);

[0019] (5) The volume of the liquid is C1-V1 or C2-V2.

[0020] The following is a further optimization and / or improvement of the second technical solution of the above invention:

[0021] The present invention has a reasonable and compact structure and is easy to use. During use, a volumetric flowmeter is used for measurement, and the results are more accurate. The pressure transmitter can measure a wide range of media, such as oil and water, and has a certain degree of corrosion resistance; it has high accuracy and high stability; it is small in size, light in weight, and easy to install, debug, and use. The differential pressure tube creates a corresponding pressure difference between the front and rear ends of the differential pressure tube through the action of other methods such as reducing the diameter. During the measurement process, there is no need to separate the gas-liquid two-phase mixed fluid, which greatly reduces the size and cost of the equipment. Continuous measurement can also be performed, and the structure sealed with the outside is safer and more reliable, with the characteristics of safety, labor saving, simplicity, and efficiency. BRIEF DESCRIPTION OF THE DRAWINGS

[0022] Attachment Figure 1 This is a schematic diagram of the main cross-sectional structure of embodiment 1 of the present invention.

[0023] The codes in the accompanying drawings are: 1 is the first pressure transmitter, 2 is the first positive displacement flowmeter, 3 is the differential pressure tube, 4 is the second pressure transmitter, 5 is the second positive displacement flowmeter, and 6 is the temperature transmitter. DETAILED DESCRIPTION

[0024] The present invention is not limited to the following embodiments, and specific implementation methods can be determined based on the technical solutions of the present invention and actual conditions.

[0025] In the present invention, for the convenience of description, the relative position relationship of each component is described based on the Figure 1 For example, the positional relationships of front, back, up, down, left, and right are based on the layout of the drawings in the specification. Figure 1 Direction is determined.

[0026] The present invention will be further described below in conjunction with the embodiments and accompanying drawings:

[0027] Example 1, as shown in the attached Figure 1 As shown, the volumetric gas-liquid two-phase flowmeter includes a first volumetric flowmeter 2, a second volumetric flowmeter 5, a first pressure transmitter 1, a second pressure transmitter 4 and a differential pressure tube 3. The first volumetric flowmeter 2, the differential pressure tube 3 and the second volumetric flowmeter 5 are fixed together in sequence. The first pressure transmitter 1 is installed at the left end of the first volumetric flowmeter 2, and the second pressure transmitter 4 is installed at the left end of the second volumetric flowmeter 5.

[0028] During use, positive displacement flowmeters do not require long straight sections of pipe to achieve a stable velocity distribution within the pipe. There are no specific requirements for velocity distribution within the pipe, greatly facilitating on-site installation. Furthermore, using a positive displacement flowmeter for measurement results is more accurate. Pressure transmitters can measure a wide range of media, including oil and water, and offer a degree of corrosion resistance. They offer high accuracy and stability, are compact and lightweight, and are easy to install, debug, and use. A corresponding pressure differential is established between the front and rear ends of the differential pressure tube, eliminating the need to separate the gas-liquid two-phase mixture during the measurement process. This significantly reduces equipment size and cost, allows for continuous measurement, and features a secure and reliable seal with external seals, making them safe, labor-saving, simple, and efficient.

[0029] The above-mentioned positive displacement gas-liquid two-phase flowmeter can be further optimized and / or improved according to actual needs:

[0030] As attached Figure 1 As shown, the inner diameter of the differential pressure tube 3 is in a funnel shape with a larger left side and a smaller right side, and the inner diameter of the right side of the differential pressure tube 3 is smaller than the inner diameter of the left end of the second volumetric flowmeter 5.

[0031] According to the demand, the diameter of the differential pressure tube 3 is variable, that is, it can be replaced according to different production to meet the use demand. During use, a corresponding pressure difference is caused at the front and rear ends of the differential pressure tube 3 by reducing the diameter or other methods.

[0032] As attached Figure 1 As shown, a temperature transmitter 6 is also included. The temperature transmitter 6 is installed at the right end of the second positive displacement flowmeter 5.

[0033] During use, after the temperature transmitter 6 measures the temperature and compensates for the temperature, it can very accurately calculate the volume occupied by the gas, thereby calculating the exact volume occupied by the liquid.

[0034] As attached Figure 1 As shown, a mounting flange is provided at the left end of the first positive displacement flowmeter 2 corresponding to the left side of the first pressure transmitter 1 , and a mounting flange is provided at the right end of the second positive displacement flowmeter 5 corresponding to the right side of the second pressure transmitter 4 .

[0035] During use, the mounting flange facilitates installation.

[0036] Example 2, according to the attached Figure 1 As shown, a measurement method using the above-mentioned volumetric gas-liquid two-phase flowmeter includes the following steps:

[0037] In the first step, the first pressure transmitter 1 measures the pressure P1 of the gas flowing through the measured metering pipeline during a metering time;

[0038] In the second step, the first positive displacement flowmeter 2 measures the volume C1 of the gas-liquid two-phase mixed fluid flowing through the measured metering pipeline within a certain metering time;

[0039] In the third step, the second pressure transmitter 4 measures the pressure P2 of the gas flowing through the differential pressure tube in the measured metering pipeline within a metering time;

[0040] In the fourth step, the second positive displacement flowmeter 5 measures the volume C2 of the gas-liquid two-phase mixed fluid after flowing through the differential pressure tube in the measured metering pipeline within a metering time;

[0041] The gas volume and liquid volume in the measured metering pipeline during a certain metering time can be calculated using the following formula:

[0042] (1) According to Boyle's law: for a certain mass of a gas, when the temperature remains constant, the pressure P is inversely proportional to the volume V, that is, P1V1=P2V2;

[0043] (2) The molecular weights of the gas and liquid flowing through the first positive displacement flowmeter 2 and the second positive displacement flowmeter 5 during a period of measurement time are the same, and the volume ratio of the gas flowing through the first positive displacement flowmeter 2 and the second positive displacement flowmeter 5 is V1 / V2=P2 / P1;

[0044] (3) The fluid volume measured by the first positive displacement flowmeter 2 and the second positive displacement flowmeter 5 is C1-C2=V1-V2;

[0045] (4) The values ​​of gas volumes V1 and V2 can be derived and calculated using formulas (1), (2), and (3);

[0046] (5) The volume of the liquid is C1-V1 or C2-V2, because C1-V1=C2-V2.

[0047] During the measurement and calculation process, due to the action of the differential pressure tube 3 through other methods such as diameter reduction, a corresponding pressure difference is caused at the front and rear ends of the differential pressure tube 3. The gas-liquid two-phase mixed fluid enters the second positive displacement flowmeter 5 driven by the pressure difference and the fluid volume is measured. Since the same gas will change significantly in volume under compression at different pressures, the greater the pressure, the smaller the volume occupied by the gas, while the liquid volume changes very little. Therefore, there will be a difference in the volume measured by the two positive displacement flowmeters in the front and back, and the difference is the change in the volume of the gas at different pressures. The volume occupied by the gas is calculated, and finally the volume occupied by the liquid is calculated, and the volume of the gas and liquid is measured. During the metering process, there is no need to separate the gas-liquid two-phase mixed fluid, which greatly reduces the equipment volume and cost, and can also be measured continuously. The structure with external sealing is safer and more reliable.

[0048] According to the attached Figure 1 As shown, the temperature transmitter 6 measures the temperature of the gas-liquid two-phase mixed fluid flowing through the measured metering pipeline during a metering time, and is used for temperature compensation to calculate more accurate gas volumes V1 and V2.

[0049] In the measurement and calculation process, after the temperature measured by the temperature transmitter 6 is compensated, the volume occupied by the gas can be calculated very accurately, thereby calculating the exact volume occupied by the liquid.

[0050] The above technical features constitute the best embodiment of the present invention, which has strong adaptability and best implementation effect. Non-essential technical features can be added or removed according to actual needs to meet the requirements of different situations.

Claims

1. A positive displacement gas-liquid two-phase flowmeter, characterized in that The invention comprises a first positive displacement flowmeter, a second positive displacement flowmeter, a first pressure transmitter, a second pressure transmitter and a differential pressure tube. The first positive displacement flowmeter, the differential pressure tube and the second positive displacement flowmeter are fixed together in sequence. The first pressure transmitter is installed at the left end of the first positive displacement flowmeter, the second pressure transmitter is installed at the left end of the second positive displacement flowmeter, the inner diameter of the differential pressure tube is funnel-shaped with a larger left side and a smaller right side, the inner diameter of the right part of the differential pressure tube is smaller than the inner diameter of the left end of the second positive displacement flowmeter, the caliber of the differential pressure tube is variable and can be replaced according to different production volumes to meet usage requirements. The positive displacement gas-liquid two-phase flowmeter also comprises a temperature transmitter, and a temperature transmitter is installed at the right end of the second positive displacement flowmeter. A mounting flange is provided at the left end of the first positive displacement flowmeter corresponding to the left side of the first pressure transmitter, and a mounting flange is provided at the right end of the second positive displacement flowmeter corresponding to the right side of the second pressure transmitter. The measurement method of the positive displacement gas-liquid two-phase flowmeter comprises: The first pressure transmitter measures the pressure P1 of the gas flowing through the measured metering pipeline during a metering time; The first positive displacement flowmeter measures the volume C1 of the gas-liquid two-phase mixed fluid flowing through the measured metering pipeline within a certain metering time; The second pressure transmitter measures the pressure P2 of the gas flowing through the differential pressure tube in the measured metering pipeline within a certain metering time; The second positive displacement flowmeter measures the volume C2 of the gas-liquid two-phase mixed fluid flowing through the differential pressure tube in the measured metering pipeline within a certain metering time; The gas volume and liquid volume in the measured metering pipeline during a certain metering time can be calculated using the following formula: (1) The molecular weights of the gas and liquid flowing through the first and second positive displacement flowmeters during a period of measurement time are the same, and the volume ratio of the gas flowing through the first and second positive displacement flowmeters is V1 / V2=P2 / P1; (2) The fluid volume measured by the first and second positive displacement flow meters is C1-C2=V1-V2; (3) Calculate the gas volumes V1 and V2 using formulas (1) and (2); (4) The volume of the liquid is C1-V1 or C2-V2.

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