A method and instrument for real-time pipeline monitoring of multiphase flow.

Abstract

This invention provides a method and instrument for real-time monitoring of multiphase flow in pipelines. The monitoring method includes the following steps: a sensor probe is connected to a main control circuit, and a high-frequency current is input to the main control circuit; the high-frequency current generates an alternating electromagnetic field through an electromagnetic excitation circuit, and induces eddy currents with the same frequency and opposite direction as the high-frequency current through an ultrasonic exciter; the eddy currents generate Lorentz force under the action of a static bias magnetic field, causing the particles of the ultrasonic exciter to vibrate at high frequency, generating an electromagnetic ultrasonic signal with the same frequency as the high-frequency current; the electromagnetic ultrasonic signal is injected into the pipeline under test along the incident angle; the central processing unit calculates the pipeline flow rate and velocity based on the time difference. This invention is used for measuring fluid flow rate, facilitating timely and accurate early warning of slug flow, and can maximize the protection of pipeline components, preventing water hammer effects caused by slug flow from damaging pipeline components.

Description

Technical Field

[0001] This invention belongs to the field of pipeline monitoring, and in particular relates to a method and instrument for real-time monitoring of multiphase flow in pipelines. Background Technology

[0002] With the continuous development of various industries, pipeline transportation technology has been increasingly widely applied, and the length of transportation pipelines has been continuously extended. However, slug flow is a very common flow pattern in two-phase flow during pipeline transportation, characterized by alternating gas and liquid columns in the pipeline. Slug flow can occur not only during pipeline shutdowns and pigging but also during changes in flow rate. Slug flow often causes significant changes in gas content and pressure within the pipeline, subjecting pipelines operating under slug flow to intermittent impact stress. Furthermore, slug flow deteriorates pipeline operating conditions, causing unstable vibrations, exacerbating corrosion of risers, leading to overflow or interruption of flow in downstream pipeline outlet separators, unstable operation of slug flow traps, and even interruption or overflow of flow in terminal separators, resulting in mechanical damage to pipeline joints and supports. Simultaneously, large liquid plugs, after leaving the pipeline end, can cause significant fluctuations in liquid levels in downstream equipment. Therefore, effective real-time monitoring of pipelines to prevent slug flow is essential.

[0003] Existing methods for real-time pipeline flow monitoring, such as differential pressure flow meters, suffer from problems such as generally low measurement accuracy, narrow range, high requirements for on-site installation conditions, and large pressure loss. Positive displacement flow meters, on the other hand, have problems such as complex calculation results, large size, and significant limitations in the types, diameters, and operating conditions of the measured media. Summary of the Invention

[0004] In view of this, the present invention aims to propose a real-time pipeline monitoring method and instrument for multiphase flow, which can be used to measure the flow rate of fluids, facilitate timely and accurate early warning of slug flow, and protect pipeline components to the greatest extent and prevent water hammer effect caused by slug flow from damaging pipeline components.

[0005] To achieve the above objectives, the technical solution of the present invention is implemented as follows:

[0006] In a first aspect, the present invention provides a method for real-time pipeline monitoring of multiphase flow, based on a gas-liquid flow meter, the gas-liquid flow meter comprising a central processing unit and at least two sensor probes, characterized by comprising the following steps:

[0007] S1. The sensor probe is connected to the main control circuit, and the main control circuit is connected to a high-frequency current; the two sensor probes are respectively staggered on both sides of the pipe being measured.

[0008] S2. The high-frequency current generates an alternating electromagnetic field through an electromagnetic excitation circuit, and induces eddy currents with the same frequency but opposite direction to the high-frequency current through an ultrasonic excitation plate.

[0009] S3. The eddy current generates Lorentz force under the action of a static bias magnetic field, which causes the particles of the ultrasonic exciter to vibrate at high frequency, generating an electromagnetic ultrasonic signal with the same frequency as the high-frequency current.

[0010] S4. The electromagnetic ultrasonic signal is injected into the pipe under test along the incident angle.

[0011] S5. The sensor probe receives the electromagnetic ultrasonic signal along the incident angle, and emits the electromagnetic ultrasonic signal along the incident angle according to steps S1 to S4.

[0012] S6. Assume that the sensor probe located near the fluid inlet is a downstream sensor probe, and the sensor probe located near the fluid outlet is a upstream sensor probe.

[0013] S7. The central processing unit obtains the time A1 when the electromagnetic ultrasonic signal generated by the downstream sensor probe passes through the pipe under test, and the time A2 when the electromagnetic ultrasonic signal generated by the upstream sensor probe on the opposite side passes through the pipe under test. Based on the time difference between A1 and A2, the flow rate and velocity of the pipe are calculated.

[0014] In a second aspect, the present invention also provides a real-time pipeline monitoring instrument for multiphase flow, wherein the gas-liquid flow meter includes a central processing unit and at least two sensor probes, characterized in that: the sensor probe includes a permanent magnet, a coil and an ultrasonic exciter; the ultrasonic exciter is a sheet made of non-ferromagnetic material, with a thickness of 1mm to 2.2mm and dimensions of 20mm in length and 10mm in width; the ultrasonic exciter is attached to the coil, the coil is attached to the permanent magnet, the permanent magnet is inclined at 35° to 65° relative to the pipeline being measured, and the magnetic field direction of the permanent magnet is perpendicular to the coil and the ultrasonic exciter.

[0015] Furthermore, the permanent magnet is made of neodymium iron boron material, with a surface magnetic field strength of 12,000 Gauss, and is rectangular in shape with dimensions of 60 mm in length, 50 mm in width, and 80 mm in height.

[0016] Furthermore, the coil has an S-shaped structure, and the spacing between the copper wire coils is 3.2mm to 3.6mm.

[0017] Furthermore, the sensor probe also includes a wedge, which is disposed at the front end of the sensor probe and abuts against the outer wall of the pipe being measured. The wedge encloses the coil and the excitation plate; the wedge is made of a polymer resin material.

[0018] Furthermore, the sensor probe includes four probes, with two sensors forming a probe group. The two probe groups are opposite each other, and the two probe groups are symmetrically arranged on both sides of the outside of the pipe being measured.

[0019] Furthermore, the main control circuit includes a high-frequency current frequency modulation circuit, a clock circuit, and a reset circuit. The high-frequency current frequency modulation circuit is used to adjust the high-frequency current, the clock circuit is used to provide the system clock, and the reset circuit is used to restore the main control circuit to its initial state.

[0020] Compared with existing technologies, the multiphase flow real-time pipeline monitoring method and monitoring instrument of the present invention have the following advantages:

[0021] The flow velocity measuring device based on the electromagnetic ultrasonic principle described in this invention has advantages such as high accuracy, non-contact measurement capability, and fast response speed. For different types of fluids with varying acoustic impedances, the flow velocity measuring device based on the electromagnetic ultrasonic principle can emit electromagnetic ultrasonic waves of different frequencies to measure flow velocity, thus expanding its application range and increasing its accuracy. Attached Figure Description

[0022] The accompanying drawings, which form part of this invention, are used to provide a further understanding of the invention. The illustrative embodiments of the invention and their descriptions are used to explain the invention and do not constitute an undue limitation of the invention. In the drawings:

[0023] Figure 1 This is a schematic diagram of the monitoring method described in an embodiment of the present invention;

[0024] Figure 2 This is a side view of the monitoring method described in an embodiment of the present invention;

[0025] Figure 3 This is a schematic diagram of the coil structure described in an embodiment of the present invention;

[0026] Figure 4 This is a schematic diagram of the second sensor probe structure according to an embodiment of the present invention;

[0027] Figure 5 This is a schematic diagram of the first sensor probe and the second sensor probe in an embodiment of the present invention;

[0028] Figure 6 This refers to the high-frequency current modulation circuit described in the embodiments of the present invention;

[0029] Figure 7 The clock circuit described in the embodiments of the present invention;

[0030] Figure 8 This is the reset circuit described in the embodiment of the present invention.

[0031] Explanation of reference numerals in the attached figures:

[0032] 1-Tested pipe; 10-Magnet; 11-Coil; 12-Ultrasonic exciter; 13-Wedge; 14-Inclined surface; 101-First sensor probe; 102-Second sensor probe; 103-Third sensor probe; 104-Fourth sensor probe; 200-Central processing unit; 201-Main control circuit; 202-Flow calculation unit. Detailed Implementation

[0033] It should be noted that, unless otherwise specified, the embodiments and features described in the present invention can be combined with each other.

[0034] The present invention will now be described in detail with reference to the accompanying drawings and embodiments.

[0035] like Figure 1 As shown, a real-time pipeline monitoring method for multiphase flow is based on a gas-liquid flow meter, which includes a central processing unit 200 and at least two sensor probes, sensor probe 101 and sensor probe 102, and includes the following steps:

[0036] like Figure 1 As shown, in S1, the sensor probe is connected to the main control circuit 201, and the main control circuit 201 is connected to a high-frequency current; the two sensor probes are respectively staggered on both sides of the pipe being tested; specifically, the first sensor probe 101 and the second sensor probe 102 are respectively connected to the main control circuit 201.

[0037] like Figure 1 As shown, in S2, the high-frequency current generates an alternating electromagnetic field through an electromagnetic excitation circuit, and induces eddy currents with the same frequency but opposite direction to the high-frequency current through an ultrasonic excitation plate; specifically, the alternating electromagnetic field is generated by an electromagnetic excitation circuit composed of a magnet 10, and eddy currents with the same frequency but opposite direction to the high-frequency current are induced by an ultrasonic excitation plate 12.

[0038] like Figure 1 As shown in Figure S3, the eddy current generates a Lorentz force under the action of a static bias magnetic field, which causes the particles of the ultrasonic exciter to vibrate at high frequency, generating an electromagnetic ultrasonic signal with the same frequency as the high-frequency current. Specifically, the eddy current generates a Lorentz force under the action of a static bias magnetic field formed by coil 11, which causes the particles of the ultrasonic exciter 12 to vibrate at high frequency, generating an electromagnetic ultrasonic signal with the same frequency as the high-frequency current.

[0039] S4. The electromagnetic ultrasonic signal is injected into the tested pipe 1 at the incident angle; as shown... Figure 2 As shown, the electromagnetic ultrasonic signal is injected into the pipe 1 under test along the incident angle θ.

[0040] like Figure 1 , Figure 2 As shown, in step S5, sensor probe 101 and sensor probe 102 receive the electromagnetic ultrasonic signal along the incident angle θ, and transmit the electromagnetic ultrasonic signal along the incident angle θ according to steps S1 to S4.

[0041] like Figure 1 , Figure 2 As shown, S6, the sensor probe located near the fluid inlet is a downstream sensor probe, and the sensor probe located near the fluid outlet is a upstream sensor probe; S7, the central processing unit acquires the time A1 of the electromagnetic ultrasonic signal generated by the downstream sensor probe passing through the pipe under test, and the time A2 of the electromagnetic ultrasonic signal generated by the upstream sensor probe passing through the pipe under test, and calculates the pipe flow rate and velocity based on the time difference between A1 and A2.

[0042] It should be further explained that there is a certain time required for the sensor probe to generate a signal and for the sensor probe on the other side to receive the signal. Similarly, there is a certain time required for the sensor probe on the other side to generate a signal and for the sensor probe on the other side to receive the signal. Due to the fluid flow in the measured pipe, there is a certain time difference between the two times. The corresponding time difference is calculated by the flow calculation unit to realize the real-time monitoring of the pipe flow rate and velocity.

[0043] In step S1, the high-frequency current is a frequency-adjustable high-frequency current. Because the acoustic impedances of single-phase and multiphase fluids are different, the main control circuit adjusts the frequency of the high-frequency current to change the frequency of the electromagnetic ultrasonic signal, enabling flow monitoring of both single-phase and multiphase fluids within the corresponding frequency range.

[0044] In this preferred embodiment, in step S3, the incident angle θ is 35° to 65°;

[0045] In step 6, the formula for calculating the pipeline flow rate is:

[0046]

[0047] Where v represents the flow velocity of the fluid in the pipe being tested, c represents the signal velocity of the electromagnetic ultrasonic wave, Δt represents the time difference between A1 and A2, and L represents the required length for the electromagnetic ultrasonic signal to pass through the pipe being tested.

[0048] The formula for calculating pipeline flow rate is as follows:

[0049]

[0050] Where Q represents the flow rate in the pipe being measured, k represents the flow correction coefficient, S represents the cross-sectional area of ​​the pipe being measured, and v represents the velocity of the fluid in the pipe being measured.

[0051] Furthermore, the time required for the electromagnetic ultrasonic signal emitted by the sensor probe to travel through the pipe being tested... The calculation formula is as follows:

[0052]

[0053] Furthermore, the time required for the electromagnetic ultrasonic signal emitted by the sensor probe on the opposite side to travel through the pipe being tested... The calculation formula is as follows:

[0054]

[0055] Furthermore, the required transmission time and difference The calculation formula is as follows:

[0056]

[0057] This invention discloses a real-time pipeline flow monitoring method for multiphase flow. It can measure the flow velocity of different types of fluids with varying acoustic impedances by emitting electromagnetic ultrasonic waves of different frequencies according to steps 1 to 6. This method has a wider range of applications and higher accuracy. The monitoring method of this invention is used to measure fluid flow rate, facilitating timely and accurate early warning of slug flow. It can maximize the protection of pipeline components and prevent water hammer effects caused by slug flow from damaging pipeline parts.

[0058] like Figure 1 , Figure 2 As shown, this invention also provides a real-time pipeline monitoring instrument for multiphase flow. The gas-liquid flow meter includes a central processing unit 200 and at least two sensor probes: a first sensor probe 101 and a second sensor probe 102. Each sensor probe includes a permanent magnet 10, a coil 11, and an ultrasonic exciter 12. The ultrasonic exciter 12 is a sheet made of non-ferromagnetic material, with a thickness of 1 mm and dimensions of 20 mm in length and 10 mm in width. The ultrasonic exciter 12 is attached to the coil 11, which is attached to the permanent magnet 10. The permanent magnet is tilted relative to the pipe being measured, and the magnetic field direction of the permanent magnet 10 is perpendicular to the coil 11 and the ultrasonic exciter 12. Based on the principle of electromagnetic ultrasound, the sensor probe generates corresponding electromagnetic ultrasonic waves by passing a high-frequency current through the permanent magnet, the coil, and the ultrasonic exciter. Specifically, as shown... Figure 5 As shown, the angle α between the centerline of the permanent magnet 10 and the axis of the pipe being measured is 90° + the incident angle θ.

[0059] In this preferred embodiment, the permanent magnet 10 is made of neodymium iron boron material, with a surface magnetic field strength of 12000 Gauss, a cuboid shape, and dimensions of 60mm in length, 50mm in width, and 80mm in height.

[0060] like Figure 3 As shown, the coil 11 has an S-shaped structure, and the spacing W between the copper wire coils is 3.2mm to 3.6mm, preferably 3.4mm in this embodiment.

[0061] like Figure 2 As shown, the sensor probe also includes a wedge 13, which is disposed at the front end of the sensor probe and abuts against the outer wall of the pipe being measured. The wedge 13 encloses the coil 11 and the excitation plate 12. The wedge 13 is made of a polymer resin material such as polyamide.

[0062] like Figure 4 As shown, the front end of the wedge 13 is an inclined surface 14, and the angle β between the inclined surface 14 and the center line of the permanent magnet 10 is 90° + incident angle θ. Furthermore, the inclined surface 14 is arranged parallel to the axis of the pipe being measured and abuts against the outer wall of the pipe being measured.

[0063] like Figure 1 As shown, the sensor probe includes four probes: a first sensor probe 101, a second sensor probe 102, a third sensor probe 103, and a fourth sensor probe 104. The first sensor probe 101 and the second sensor probe 102 form a group of probes, with each group of probes positioned opposite each other. Similarly, the third sensor probe 103 and the fourth sensor probe 104 are positioned opposite each other. The two groups of probes are symmetrically arranged on both sides of the outside of the pipe being measured 1. When the fluid inside the pipe is in a gas-liquid stratified flow, the four-sensor probe configuration enables separate monitoring of the gas and liquid phase flow rates.

[0064] The main control circuit includes a high-frequency current frequency modulation circuit, a clock circuit, and a reset circuit. The high-frequency current frequency modulation circuit is used to adjust the high-frequency current, the clock circuit is used to provide the system clock, and the reset circuit is used to restore the main control circuit to its initial state.

[0065] Among them, the high-frequency current frequency modulation circuit is as follows Figure 6 As shown, the high-frequency current frequency modulation circuit uses a frequency converter to adjust the required frequency, thereby realizing the rectification, filtering and inversion of high-frequency current.

[0066] Clock circuits such as Figure 7 As shown, the clock circuit provides a highly stable clock reference to increase measurement accuracy. In this embodiment, a passive crystal oscillator of 6MHz to 8MHz is preferred as the chip clock source, and an STM32 is selected as the chip.

[0067] Reset circuit such as Figure 8 As shown, the purpose of the reset circuit is to restore the main control circuit to its initial state, prevent system program errors and reset in case of system abnormalities, and refresh data to prevent system crashes and data loss.

[0068] This invention also provides a real-time pipeline monitoring instrument for multiphase flow. The sensor probe structure, based on the electromagnetic ultrasonic principle, includes a permanent magnet, a coil circuit, and an ultrasonic exciter. Passing a high-frequency current through the probe generates corresponding electromagnetic ultrasonic waves. Electromagnetic ultrasonic waves offer advantages such as high precision, no need for coupling agents, non-contact operation, suitability for high-temperature detection, and ease of exciting various ultrasonic wave patterns. When the main control circuit 201 generates a high-frequency current of 100kHz to 400kHz, it primarily monitors the flow of various liquids; when the main control circuit 201 generates a high-frequency current of 60kHz to 120kHz, it primarily monitors the flow of various gases; when the gas and liquid are mixed, corresponding frequency adjustment tests are performed for different flow patterns to extract the most stable flow value for monitoring.

[0069] The above description is only a preferred embodiment of the present invention and is not intended to limit the present invention. Any modifications, equivalent substitutions, improvements, etc., made within the spirit and principles of the present invention should be included within the protection scope of the present invention.

Claims

1. A method for real-time pipeline monitoring of multiphase flow, based on a gas-liquid flow meter, wherein the gas-liquid flow meter includes a central processing unit and at least two sensor probes, characterized in that, Includes the following steps: S1. The sensor probe is connected to the main control circuit, and the main control circuit is connected to a high-frequency current; the two sensor probes are respectively staggered on both sides of the pipe being measured. S2. The high-frequency current generates an alternating electromagnetic field through an electromagnetic excitation circuit, and induces eddy currents with the same frequency but opposite direction to the high-frequency current through an ultrasonic excitation plate. S3. The eddy current generates Lorentz force under the action of a static bias magnetic field, which causes the particles of the ultrasonic exciter to vibrate at high frequency, generating an electromagnetic ultrasonic signal with the same frequency as the high-frequency current. S4. The electromagnetic ultrasonic signal is injected into the pipe under test along the incident angle. S5. The sensor probe receives the electromagnetic ultrasonic signal along the incident angle, and emits the electromagnetic ultrasonic signal along the incident angle according to steps S1 to S4. S6. Assume that the sensor probe located near the fluid inlet is a downstream sensor probe, and the sensor probe located near the fluid outlet is a upstream sensor probe. S7. The central processing unit obtains the time A1 when the electromagnetic ultrasonic signal generated by the downstream sensor probe passes through the pipe under test, and the time A2 when the electromagnetic ultrasonic signal generated by the upstream sensor probe on the opposite side passes through the pipe under test. Based on the time difference between A1 and A2, the flow rate and velocity of the pipe are calculated. In step S7, the formula for calculating the pipe flow velocity is: ， Where v represents the flow velocity of the fluid in the pipe being tested, c represents the signal velocity of the electromagnetic ultrasonic wave, Δt represents the time difference between A1 and A2, and L represents the required length for the electromagnetic ultrasonic signal to pass through the pipe being tested. The formula for calculating pipeline flow rate is as follows: ， Where Q represents the flow rate in the pipe being measured, k represents the flow correction coefficient, S represents the cross-sectional area of ​​the pipe being measured, and v represents the flow velocity of the fluid in the pipe being measured. In step S4, the incident angle is 35° to 65°; The sensor probe includes a permanent magnet, a coil, and an ultrasonic exciter. The ultrasonic exciter is a sheet made of non-ferromagnetic material with a thickness of 1 mm to 2.2 mm and dimensions of 20 mm in length and 10 mm in width. The ultrasonic exciter is attached to the coil, and the coil is attached to the permanent magnet. The permanent magnet is tilted at 35° to 65° relative to the pipe being measured, and the magnetic field direction of the permanent magnet is perpendicular to the coil and the ultrasonic exciter.

2. The method for real-time pipeline monitoring of multiphase flow according to claim 1, characterized in that: In step S1, the high-frequency current is an adjustable high-frequency current.

3. The method for real-time pipeline monitoring of multiphase flow according to claim 1, characterized in that: The permanent magnet is made of neodymium iron boron material, with a surface magnetic field strength of 12,000 Gauss, and is rectangular in shape with dimensions of 60 mm in length, 50 mm in width, and 80 mm in height.

4. The method for real-time pipeline monitoring of multiphase flow according to claim 3, characterized in that: The coil has an S-shaped structure, and the spacing between the copper wire coils is 3.2mm to 3.6mm.

5. The method for real-time pipeline monitoring of multiphase flow according to claim 4, characterized in that: The sensor probe also includes a wedge, which is disposed at the front end of the sensor probe and abuts against the outer wall of the pipe being measured. The wedge encloses the coil and the excitation plate; the wedge is made of polymer resin material.

6. The method for real-time pipeline monitoring of multiphase flow according to claim 1, characterized in that: The sensor probes include four, with two sensors forming a group of probes. The two sensor probes in a group are opposite each other, and the two groups of probes are symmetrically arranged on both sides of the outside of the pipe being measured.

7. The method for real-time pipeline monitoring of multiphase flow according to claim 1, characterized in that: The main control circuit includes a high-frequency current frequency modulation circuit, a clock circuit, and a reset circuit. The high-frequency current frequency modulation circuit is used to adjust the high-frequency current, the clock circuit is used to provide the system clock, and the reset circuit is used to restore the main control circuit to its initial state.

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