A steam gas-liquid separator and its real-time liquid level monitoring method

Abstract

This application relates to the technical field of liquid level measurement, and specifically relates to a steam gas-liquid separator and a method for real-time monitoring of its liquid level. The method includes: dividing the echo signal into a liquid surface echo signal and multiple positioning echo signals; determining the electromagnetic average velocity during the time period where each positioning echo signal is located; obtaining the electromagnetic echo signal, and based on the degree of dispersion of the electromagnetic echo signal and the average distribution of the electromagnetic average velocities during the time periods where all the positioning echo signals are located, determining the corrected velocity of the electromagnetic wave, and combining the length of the liquid surface echo signal, the sampling frequency, the distance from the electromagnetic wave emission position to the bottom of the steam gas-liquid separator, and the interval between adjacent positioning points to determine the liquid level height of the steam gas-liquid separator at the current moment. This application improves the accuracy of measuring the liquid level height in the steam gas-liquid separator by analyzing the influence of the uneven distribution of steam in the separator on the propagation velocity of the electromagnetic wave.

Description

Technical Field

[0001] This application relates to the technical field of liquid level measurement, and specifically relates to a steam-gas-liquid separator and a method for real-time monitoring of its liquid level. Background Art

[0002] During the use of a steam-gas-liquid separator, real-time liquid level detection is required to ensure a stable liquid level to maintain the problem of the output liquid level. Due to the harsh working conditions such as high temperature, high pressure, and high saturated steam inside the steam-gas-liquid separator, a guided wave radar level gauge is usually used as the measuring device to reduce the influence of the harsh conditions on the measurement results.

[0003] Based on the characteristic that the guided wave will be reflected and then return when it touches the liquid surface, the guided wave radar level gauge measures the distance from the liquid surface to the measurement point through the reflection time of the guided wave, and then obtains the liquid surface height. However, since there is steam in the tank, and the steam will affect the propagation speed of the guided wave inside the waveguide rod, the measured liquid surface height will be affected by the steam, resulting in an error in the measurement of the liquid surface height. In response to the influence of steam, the existing liquid level correction method sets reference points on the waveguide rod, estimates the guided wave velocity through reference data, and then completes the compensation. This method does not fully consider the irregular distribution of steam in the steam-gas-liquid separator. It first assumes that the steam distribution inside the separator is uniform and then corrects the liquid level measurement data, thereby reducing the accuracy of the liquid surface height measurement in the steam-gas-liquid separator. Summary of the Invention

[0004] In order to solve the above technical problems, this application provides a steam-gas-liquid separator and a method for real-time monitoring of its liquid level to solve the existing problems.

[0005] In a first aspect, an embodiment of this application provides a method for real-time monitoring of the liquid level of a steam-gas-liquid separator, and the method includes the following steps:

[0006] Send electromagnetic waves to the waveguide rod in the steam-gas-liquid separator through a guided wave radar level gauge, and obtain the echo signal at the current moment in the guided wave radar level gauge, where there are multiple equally spaced positioning points on the waveguide rod;

[0007] Obtain the liquid surface echo moment and all positioning echo moments in the echo signal based on the extreme value distribution in the echo signal; based on the liquid surface echo moment and all positioning echo moments, divide the echo signal into a liquid surface echo signal and multiple positioning echo signals;

[0008] Based on the lengths of the respective positioning echo signals and the preset sampling frequency, and in combination with the intervals between adjacent positioning points, determine the electromagnetic average velocity of each positioning echo signal; based on the similarity between each positioning echo signal and the liquid surface echo signal, determine the velocity distribution weight of each positioning echo signal, and in combination with the electromagnetic average velocity, determine the velocity correction term of the electromagnetic wave;

[0009] Denote the echo signal between the first positioning echo moment and the liquid surface echo moment as the electromagnetic echo signal, and based on the dispersion degree of all elements in the electromagnetic echo signal and the average distribution of the electromagnetic average velocities of all positioning echo signals, determine the corrected velocity of the electromagnetic wave;

[0010] Based on the length of the liquid surface echo signal, the corrected velocity, and the sampling frequency, determine the distance between the positioning point corresponding to the last positioning echo moment and the steam-gas-liquid interface, and in combination with the distance from the electromagnetic wave emission position to the bottom of the steam-gas-liquid separator and the interval between adjacent positioning points, determine the liquid level height of the steam-gas-liquid separator at the current moment.

[0011] Preferably, the obtaining of the liquid surface echo moment and all positioning echo moments in the echo signal includes:

[0012] Take the echo signal as the input of the extreme value detection algorithm and output all the maximum values in the echo signal;

[0013] Denote the first maximum value greater than the preset threshold as the positioning echo intensity, set the upper limit of the interval D as the product of the first preset value and the positioning echo intensity, and the lower limit as the product of the second preset value and the positioning echo intensity;

[0014] If the maximum value is within the interval D, then denote the corresponding moment of this maximum value in the echo signal as the positioning echo moment, and denote the corresponding moment of the maximum value after the last positioning echo moment in the echo signal as the liquid surface echo moment, where the first preset value is greater than the second preset value.

[0015] Preferably, the dividing of the echo signal into the liquid surface echo signal and multiple positioning echo signals includes:

[0016] Denote the echo signal between the moment when the guided wave radar level gauge starts to receive the echo signal and the first positioning echo moment, and the echo signal between adjacent two positioning echo moments as the positioning echo signals; denote the echo signal between the last positioning echo moment and the liquid surface echo moment as the liquid surface echo signal.

[0017] Preferably, the electromagnetic average velocity of each positioning echo signal is the result of multiplying the length of each positioning echo signal, the preset sampling frequency, and the interval between adjacent positioning points.

[0018] Preferably, the velocity distribution weight of each positioning echo signal is the normalized value of the similarity between each positioning echo signal and the liquid surface echo signal.

[0019] Preferably, the velocity correction term of the electromagnetic wave is the sum of the products of the velocity distribution weights of all positioning echo signals and the corresponding electromagnetic average velocities.

[0020] Preferably, the method for determining the velocity correction weight of the electromagnetic wave is as follows:

[0021] Calculate the coefficient of variation of all elements in the electromagnetic echo signal. If the coefficient of variation is less than 1, then set the velocity correction weight of the electromagnetic wave equal to the coefficient of variation; otherwise, set the velocity correction weight of the electromagnetic wave equal to 1.

[0022] The corrected velocity of the electromagnetic wave is expressed as: ; In the formula, represents the mean value of the electromagnetic average velocities of all positioning echo signals; represents the velocity correction weight of the electromagnetic wave; represents the velocity correction term of the electromagnetic wave.

[0023] Preferably, the expression for the distance between the positioning point corresponding to the last positioning echo moment and the vapor-liquid interface of the steam is: ; In the formula, represents the distance between the positioning point corresponding to the last positioning echo moment and the vapor-liquid interface of the steam; represents the length of the liquid surface echo signal; F represents the preset sampling frequency.

[0024] Preferably, the expression for the liquid level height of the steam-liquid separator at the current moment is: ; In the formula, represents the liquid level height of the steam-liquid separator at the current moment; represents the distance from the electromagnetic wave emission position to the bottom of the steam-liquid separator; H represents the number of all positioning points on the waveguide rod; d represents the interval between adjacent positioning points.

[0025] In a second aspect, an embodiment of the present application further provides a steam-liquid separator, including a memory, a processor, and a computer program stored in the memory and running on the processor. When the processor executes the computer program, the steps of the liquid level real-time monitoring method of the steam-liquid separator described in any one of the above are implemented.

[0026] An embodiment of the present application provides a steam-liquid separator and its liquid level real-time monitoring method. The method includes the following steps:

[0027] The present application has at least the following beneficial effects:

[0028] This application uses an extreme value detection algorithm to obtain the liquid level echo time and all positioning echo times in the echo signal. The liquid level echo time is after the last positioning echo time. Based on the liquid level echo time and all positioning echo times, the echo signal is divided into a liquid level echo signal and multiple positioning echo signals. The beneficial effect is that by accurately distinguishing the liquid level echo signal and the positioning echo signals, the liquid level height can be located more accurately, improving the accuracy of liquid level measurement;

[0029] This application determines the electromagnetic average velocity of each positioning echo signal based on the length of each positioning echo signal and the preset sampling frequency, in combination with the interval between adjacent positioning points. Based on the similarity between each positioning echo signal and the liquid level echo signal, the velocity distribution weight of each positioning echo signal is determined, and in combination with the electromagnetic average velocity, the velocity correction term of the electromagnetic wave is determined. The beneficial effect is that it can more accurately reflect the actual propagation velocity of the electromagnetic wave in the waveguide rod, calculate the liquid level height more accurately, and thus improve the accuracy of liquid level measurement;

[0030] This application records the echo signal between the first positioning echo time and the liquid level echo time as the electromagnetic echo signal. Based on the discreteness of the electromagnetic echo signal, the velocity correction weight of the electromagnetic wave is determined. In combination with the average distribution of the electromagnetic average velocities of all positioning echo signals, the corrected velocity of the electromagnetic wave is determined. The beneficial effect is that it fully considers the influence of the uneven distribution of steam in the separator on the propagation velocity of the electromagnetic wave, can more accurately reflect the actual propagation velocity of the electromagnetic wave in the waveguide rod, and improve the accuracy of liquid level measurement;

[0031] This application determines the distance between the positioning point corresponding to the last positioning echo time and the steam-gas-liquid interface based on the length of the liquid level echo signal, the corrected velocity, and the sampling frequency. In combination with the distance from the electromagnetic wave emission position to the bottom of the steam-gas-liquid separator and the interval between adjacent positioning points, the liquid level height of the steam-gas-liquid separator at the current moment is determined, improving the accuracy of measuring the liquid level height in the steam-gas-liquid separator. Description of the Drawings

[0032] To more clearly illustrate the technical solutions and advantages in the embodiments of this application or the prior art, the following will briefly introduce the drawings required for the description of the embodiments or the prior art. Obviously, the drawings in the following description are only some embodiments of this application. For those of ordinary skill in the art, without creative efforts, other drawings can be obtained based on these drawings.

[0033] Figure 1 It is a step flow chart of a method for real-time monitoring of the liquid level of a steam-gas-liquid separator provided by an embodiment of this application;

[0034] Figure 2 Schematic diagram of echo signals before and after filtering provided by an embodiment of the present application;

[0035] Figure 3 Schematic diagram of the process of extracting the speed correction term provided by an embodiment of the present application;

[0036] Figure 4 Schematic diagram of the process of extracting the corrected speed of electromagnetic waves provided by an embodiment of the present application. Detailed implementation manners

[0037] In order to further elaborate on the technical means and effects adopted by the present application to achieve the predetermined invention purpose, the following provides a detailed description of a steam-gas-liquid separator and its real-time liquid level monitoring method proposed according to the present application, including its specific implementation manners, structures, features, and effects, in conjunction with the accompanying drawings and preferred embodiments. In the following description, different "one embodiment" or "another embodiment" do not necessarily refer to the same embodiment. In addition, the specific features, structures, or characteristics in one or more embodiments can be combined in any suitable form.

[0038] Unless otherwise defined, all technical and scientific terms used herein have the same meaning as commonly understood by those skilled in the technical field to which the present application belongs.

[0039] The following specifically describes the specific solution of a steam-gas-liquid separator and its real-time liquid level monitoring method provided by the present application in conjunction with the accompanying drawings.

[0040] An embodiment of the present application provides a steam-gas-liquid separator and its real-time liquid level monitoring method. Specifically, the following is a steam-gas-liquid separator and its real-time liquid level monitoring method. Please refer to Figure 1 and the method includes the following steps:

[0041] Step S1: Send electromagnetic waves to the waveguide rod in the steam-gas-liquid separator through a guided wave radar level gauge, and obtain the echo signal at the current moment in the guided wave radar level gauge.

[0042] Send electromagnetic waves to the waveguide rod inserted into the steam-gas-liquid separator through the signal generation module of the guided wave radar level gauge, and receive the echo signal through the signal reception module of the guided wave radar level gauge.

[0043] Among them, positioning points are installed at equal intervals on the waveguide rod. The distance from the positioning point to the position where the electromagnetic wave is emitted is fixed. The positioning point will reflect part of the guided wave, and the guided wave speed can be analyzed through the guided wave reflected by the positioning point, thereby correcting the liquid level measurement result.

[0044] Obtain the echo signal at the current moment in the signal receiving module of the guided wave radar level gauge, set the preset sampling frequency as F, and the obtained echo signal is a vector, where each element in the vector represents the intensity of the echo signal at the corresponding moment.

[0045] It should be noted that the values of the preset sampling frequency F and the interval between adjacent positioning points are both set artificially. In this embodiment, the value of the preset sampling frequency F is 6 GHz, and the value of the interval between adjacent positioning points is 1 m. Implementers can also set them according to specific situations, and this embodiment does not make special restrictions.

[0046] Step S2: Based on the extreme value distribution in the echo signal, obtain the liquid surface echo moment and all positioning echo moments in the echo signal. The liquid surface echo moment is after the last positioning echo moment; based on the liquid surface echo moment and all positioning echo moments, divide the echo signal into a liquid surface echo signal and multiple positioning echo signals.

[0047] The positioning points of the waveguide rod in the air and the steam-gas liquid surface will both reflect a certain echo. This part of the echo appears as the maximum value points of the signal in the echo signal. Therefore, in this embodiment, an extreme value detection algorithm is used to obtain the information of the positioning points in the air and the steam-gas liquid. Specifically:

[0048] When using the extreme value detection algorithm, it is necessary to eliminate the interference caused by the high-frequency jitter of the data in the echo signal. Therefore, a filtering algorithm is used to eliminate the interference caused by the high-frequency jitter of the data in the echo signal.

[0049] It should be noted that there are many commonly used filtering algorithms. In this embodiment, the mean filtering algorithm is used to eliminate the interference caused by the high-frequency jitter of the data in the echo signal. Implementers can also use other filtering algorithms such as Gaussian filtering and median filtering. This embodiment does not make special restrictions on the selection of the filtering algorithm.

[0050] Among them, mean filtering is a well-known technology in the field of data processing, and its specific principle will not be elaborated here.

[0051] Furthermore, take the echo signal as the input of the extreme value detection algorithm and output all the maximum values in the echo signal;

[0052] Record the first maximum value greater than the preset threshold as the positioning echo intensity, set the upper limit of the interval D as the product of the first preset value and the positioning echo intensity, and the lower limit as the product of the second preset value and the positioning echo intensity (Note: Since the positioning point is usually a point with a large impedance change, the signal intensity it reflects is relatively high, and the maximum value can be identified according to the signal intensity);

[0053] Among them, the value of the preset threshold is set artificially. In this embodiment, the value of the preset threshold is 5000 mW. Implementers can also set it according to specific situations, and this embodiment does not make special restrictions.

[0054] If the maximum value is within the interval D, the corresponding time of this maximum value in the echo signal is recorded as the positioning echo time, and the corresponding time of the maximum value after the last positioning echo time in the echo signal is recorded as the liquid level echo time, where the first preset value is greater than the second preset value.

[0055] It should be noted that the values of the first preset value and the second preset value are both set artificially. In this embodiment, the value of the first preset value is 1.2, and the value of the second preset value is 0.9. Implementers can also set them according to specific situations by themselves, and this embodiment does not make special restrictions.

[0056] It should be understood that the positioning echo time is essentially the time when the echo is reflected from the positioning point on the waveguide rod located in the air, and the liquid level echo time refers to the time when the echo is reflected from the vapor-liquid interface.

[0057] Among them, the extreme value detection algorithm is a well-known technology, and the specific process of obtaining the maximum value point will not be elaborated here.

[0058] Preferably, the schematic diagram of the echo signal before and after filtering provided in this embodiment is as Figure 2 shown, Figure 2 In Figure a, it represents the echo signal before filtering. Among them, the signals with higher signal intensity in the echo signal are the positioning echo signals reflected from the positioning points on the waveguide rod, and the last wave peak with higher signal intensity is the liquid level echo signal; Figure 2 In Figure b, it represents the echo signal after filtering. Among them, the signals with higher signal intensity in the echo signal are the positioning echo signals reflected from the positioning points on the waveguide rod, and the last wave peak with higher signal intensity is the liquid level echo signal, which eliminates the influence of high-frequency fluctuations of the data in the echo signal compared with Figure a; in Figures a and b, the abscissa represents the number of sampling points, and the ordinate represents the signal intensity, with the unit of mW.

[0059] Furthermore, based on the liquid level echo time and all positioning echo times, the echo signal is divided into a liquid level echo signal and multiple positioning echo signals. Specifically: the echo signals between the time when the guided wave radar level gauge starts to receive the echo signal and the first positioning echo time, as well as the echo signals between adjacent two positioning echo times, are all recorded as positioning echo signals; the echo signal between the last positioning echo time and the liquid level echo time is recorded as the liquid level echo signal.

[0060] It should be especially noted that usually the electromagnetic wave emission position does not coincide with the vapor-liquid interface, and there is a minimum distance between the two. In this embodiment, this distance is 5 meters, which means that there are at least 4 positioning points (when the liquid level position coincides with the 5th positioning point, there are 4 positioning points).

[0061] Step S3: Based on the lengths of the respective positioning echo signals and the preset sampling frequency, combined with the interval between adjacent positioning points, determine the electromagnetic average velocity of each positioning echo signal; based on the similarity between each positioning echo signal and the liquid surface echo signal, determine the velocity distribution weight of each positioning echo signal, and combine the electromagnetic average velocity to determine the velocity correction term of the electromagnetic wave.

[0062] When the existing guided wave radar level gauge measures the liquid level in a steam environment, the velocity of the electromagnetic wave in the waveguide rod is regarded as the same throughout the process. When using a guided wave radar level gauge to measure the liquid level in a steam-liquid separator filled with steam, the steam around the waveguide rod will cause the velocity of the electromagnetic wave inside the waveguide rod to change. When the wave velocity of the electromagnetic wave changes, a certain reflection signal will be generated, and this reflection signal is included in the echo signal, which may affect the velocity of the electromagnetic wave in the waveguide rod, thereby causing a liquid level measurement error. Therefore, the wave velocity of the electromagnetic wave can be corrected by analyzing the change of the echo signal. Specifically:

[0063] (1) Since the positions of the positioning points are fixed, and the steam is randomly distributed in the steam-liquid separator, the steam is evenly distributed in space as a whole. However, due to the continuous flow of steam in the steam-liquid separator, the distribution of steam is uneven locally. And the steam density will affect the propagation velocity of the electromagnetic wave in the waveguide rod, thereby resulting in different average velocities of the electromagnetic wave propagating at different positioning points.

[0064] Therefore, based on the lengths of the respective positioning echo signals and the preset sampling frequency, combined with the interval between adjacent positioning points, determine the electromagnetic average velocity of each positioning echo signal to characterize the propagation velocity information of the electromagnetic wave in the waveguide rod. Specifically:

[0065] Count the lengths of the respective positioning echo signals, and use the result of multiplying the length of each positioning echo signal, the preset sampling frequency, and the interval between adjacent positioning points as the electromagnetic average velocity of each positioning echo signal.

[0066] (2) The positioning echo signal contains the velocity change information of the electromagnetic wave when propagating at different positioning points, and the liquid surface echo signal contains the velocity change information of the electromagnetic wave from the last positioning echo moment to the liquid surface echo moment. Therefore, the greater the similarity between the liquid surface echo signal and the positioning echo signal, the more similar the steam distributions between the two, and the more similar the velocity change situations of the electromagnetic wave in the two propagation paths.

[0067] Therefore, based on the similarity between each positioning echo signal and the liquid surface echo signal, determine the velocity distribution weight of each positioning echo signal. Specifically:

[0068] The normalized value of the similarity between each positioning echo signal and the liquid surface echo signal is used as the velocity distribution weight of each positioning echo signal;

[0069] It should be noted that there are many methods for calculating the similarity between signals. In this embodiment, the cosine similarity between each positioning echo signal and the liquid surface echo signal is calculated to measure the similarity degree between signals. Implementers can also use other methods for measuring the similarity between signals, such as the reciprocal of the Euclidean distance. There is no special limitation on the selection of the method for measuring the similarity between signals in this embodiment.

[0070] Among them, the calculation method of cosine similarity is a well-known technology, and its specific calculation steps will not be elaborated here.

[0071] (3) The greater the velocity distribution weight, the closer the average velocity of the electromagnetic wave in the corresponding period of the liquid surface echo signal is to the average velocity of the electromagnetic wave in the corresponding period of the positioning echo signal, and the more the average velocity of the electromagnetic wave in the corresponding period of the positioning echo signal should be used to characterize the average velocity of the electromagnetic wave in the corresponding period of the liquid surface echo signal. Therefore, based on the velocity distribution weights of each positioning echo signal and in combination with the electromagnetic average velocity, the velocity correction term of the electromagnetic wave is determined, specifically:

[0072] The velocity correction term of the electromagnetic wave is the sum of the products of the velocity distribution weights of all positioning echo signals and the corresponding electromagnetic average velocities.

[0073] It can be understood from the velocity correction term of the electromagnetic wave that the greater the velocity distribution weight, the closer the average velocity of the reflection order of the electromagnetic wave in the corresponding section of the liquid surface echo signal is to the average velocity of the electromagnetic wave in the corresponding period of the positioning echo signal, and the more the average velocity of the electromagnetic wave in the corresponding period of the positioning echo signal should be used to characterize the average velocity of the electromagnetic wave in the corresponding period of the liquid surface echo signal, and the greater the obtained velocity correction term of the electromagnetic wave; on the contrary, the smaller the velocity distribution weight, the smaller the degree of closeness between the average velocity of the electromagnetic wave in the corresponding period of the liquid surface echo signal and the average velocity of the electromagnetic wave in the corresponding period of the positioning echo signal, and the smaller the obtained velocity correction term of the electromagnetic wave.

[0074] Preferably, the schematic diagram of the velocity correction term extraction process provided in this embodiment is as Figure 3 shown.

[0075] Step S4: Denote the echo signals between the first positioning echo moment and the liquid surface echo moment as electromagnetic echo signals. Based on the dispersion degree of all elements in the electromagnetic echo signals and the average distribution of the electromagnetic average velocities of all positioning echo signals, determine the correction velocity of the electromagnetic wave. Based on the length of the liquid surface echo signal, the correction velocity, and the sampling frequency, determine the distance between the positioning point corresponding to the last positioning echo moment and the steam-gas-liquid interface, and combine the distance from the electromagnetic wave emission position to the bottom of the steam-gas-liquid separator and the interval between adjacent positioning points to determine the liquid level height of the steam-gas-liquid separator at the current moment.

[0076] There is a certain error in the velocity obtained by considering the propagation velocity of the electromagnetic wave in the waveguide rod as uniform; the velocity correction term takes into account the uneven distribution of the steam. The electromagnetic wave is not uniform in the waveguide rod. Therefore, based on the dispersion degree of all elements in the electromagnetic echo signals, determine the velocity correction weight of the electromagnetic wave. Combine the average distribution of the electromagnetic average velocities of all positioning echo signals to determine the correction velocity of the electromagnetic wave. Based on the length of the liquid surface echo signal, the correction velocity, and the sampling frequency, determine the distance between the positioning point corresponding to the last positioning echo moment and the steam-gas-liquid interface, and combine the distance from the electromagnetic wave emission position to the bottom of the steam-gas-liquid separator and the interval between adjacent positioning points to determine the liquid level height of the steam-gas-liquid separator at the current moment. Eliminate the measurement error caused by the average velocity through the velocity correction term, and further eliminate the calculation error caused by the traditional liquid level measurement method. Specifically:

[0077] (1) Denote the echo signals between the first positioning echo moment and the liquid surface echo moment as electromagnetic echo signals;

[0078] Calculate the coefficient of variation of all elements in the electromagnetic echo signals. If the coefficient of variation is less than 1, let the velocity correction weight of the electromagnetic wave be equal to the coefficient of variation; otherwise, if the coefficient of variation is greater than or equal to 1, it is considered that the steam distribution in the steam-gas-liquid separator is too uneven, and let the velocity correction weight of the electromagnetic wave be equal to 1.

[0079] Among them, the calculation process of the coefficient of variation is a well-known technology, and its specific calculation steps will not be elaborated.

[0080] (2) Further, based on the velocity correction weight of the electromagnetic wave, combine the average distribution of the electromagnetic average velocities of all positioning echo signals to determine the correction velocity of the electromagnetic wave. Specifically:

[0081] The correction velocity of the electromagnetic wave The expression of is: ; In the formula, represents the mean value of the electromagnetic average velocities of all positioning echo signals; represents the velocity correction weight of the electromagnetic wave; Represents the speed correction term of the electromagnetic wave.

[0082] The speed change of the electromagnetic wave in the waveguide rod caused by uneven steam distribution is characterized by the speed correction term to eliminate the measurement error brought by the traditional liquid level measurement method, and the corrected speed of the electromagnetic wave is obtained.

[0083] Preferably, the schematic diagram of the extraction process of the corrected speed of the electromagnetic wave provided in this embodiment is as Figure 4 shown.

[0084] (3) Further, based on the length of the liquid surface echo signal, the corrected speed, and the sampling frequency, determine the distance between the positioning point corresponding to the last positioning echo moment and the steam-gas-liquid interface, specifically:

[0085] The distance between the positioning point corresponding to the last positioning echo moment and the steam-gas-liquid interface The expression is: ; In the formula, represents the length of the liquid surface echo signal; F represents the preset sampling frequency.

[0086] (4) Further, based on the distance between the positioning point corresponding to the last positioning echo moment and the steam-gas-liquid interface, and in combination with the distance from the electromagnetic wave emission position to the bottom of the steam-gas-liquid separator and the interval between adjacent positioning points, determine the liquid level height of the steam-gas-liquid separator at the current moment, specifically:

[0087] The liquid level height of the steam-gas-liquid separator at the current moment The expression is: ; In the formula, represents the distance from the electromagnetic wave emission position to the bottom of the steam-gas-liquid separator; H represents the number of all positioning points on the waveguide rod; d represents the interval between adjacent positioning points.

[0088] It should be noted that: the above sequence of embodiments of the present application is only for description and does not represent the advantages and disadvantages of the embodiments. And the above describes specific embodiments of this specification. In addition, the processes depicted in the drawings do not necessarily require the specific order or continuous order shown to achieve the desired result. In some embodiments, multitasking and parallel processing are also possible or may be advantageous.

[0089] Based on the same inventive concept as the above method, an embodiment of the present application also provides a steam-gas-liquid separator, including a memory, a processor, and a computer program stored in the memory and running on the processor. When the processor executes the computer program, it implements the steps of the liquid level real-time monitoring method of a steam-gas-liquid separator described in any one of the above.

[0090] Each embodiment in this specification is described in a progressive manner. For the same or similar parts among the embodiments, reference can be made to each other, and the key point of each embodiment is to illustrate the differences from other embodiments.

[0091] The above-described embodiments are only used to illustrate the technical solutions of the present application, rather than to limit them; any modification to the technical solutions recorded in the foregoing embodiments, or any equivalent replacement of some of the technical features, does not make the essence of the corresponding technical solutions deviate from the scope of the technical solutions of each embodiment of the present application, and shall be included within the protection scope of the present application.

Claims

1. A method for real-time monitoring of liquid level in a steam gas-liquid separator, characterized in that: The method comprises the following steps: The guided wave radar level meter sends electromagnetic waves to the waveguide rod in the steam gas-liquid separator, and obtains the echo signal at the current moment in the guided wave radar level meter, wherein there are multiple positioning points distributed at equal intervals on the waveguide rod; Obtaining the liquid surface echo moment and all positioning echo moments in the echo signal based on the extreme value distribution in the echo signal; dividing the echo signal into a liquid surface echo signal and a plurality of positioning echo signals based on the liquid surface echo moment and all positioning echo moments; Based on the length of each positioning echo signal and the preset sampling frequency, combined with the interval between adjacent positioning points, the electromagnetic average speed of each positioning echo signal is determined; based on the similarity between each positioning echo signal and the liquid surface echo signal, the speed distribution weight of each positioning echo signal is determined, and combined with the electromagnetic average speed, the speed correction term of the electromagnetic wave is determined; The echo signal between the first positioning echo moment and the liquid surface echo moment is recorded as the electromagnetic echo signal, and the corrected speed of the electromagnetic wave is calculated. , the expression is: ; In the formula, It represents the mean value of the electromagnetic average velocity of all positioning echo signals; Represents the speed correction weight of electromagnetic waves; represents the velocity correction term of electromagnetic waves; Based on the length of the liquid surface echo signal, the correction speed and the sampling frequency, the distance between the positioning point corresponding to the last positioning echo moment and the steam gas-liquid liquid surface is determined, and combined with the distance from the electromagnetic wave emission position to the bottom of the steam gas-liquid separator and the interval between adjacent positioning points, the liquid level of the steam gas-liquid separator at the current moment is determined.

2. A method for real-time monitoring of liquid level of a steam gas-liquid separator according to claim 1, characterized in that: The step of obtaining the liquid surface echo moment and all positioning echo moments in the echo signal includes: The echo signal is used as the input of the extreme value detection algorithm, and all the maximum values ​​in the echo signal are output; The first maximum value greater than the preset threshold is recorded as the positioning echo intensity, and the upper limit of interval D is set to the product of the first preset value and the positioning echo intensity, and the lower limit is set to the product of the second preset value and the positioning echo intensity; If the maximum value is in interval D, the time corresponding to the maximum value in the echo signal is recorded as the positioning echo time, and the time corresponding to the maximum value after the last positioning echo time in the echo signal is recorded as the liquid surface echo time, where the first preset value is greater than the second preset value.

3. A method for real-time monitoring of liquid level of a steam gas-liquid separator according to claim 1, characterized in that: The step of dividing the echo signal into a liquid surface echo signal and a plurality of positioning echo signals comprises: The echo signals between the moment when the guided wave radar level meter starts to receive the echo signal and the moment of the first positioning echo, as well as the echo signals between two adjacent positioning echo moments, are all recorded as positioning echo signals; the echo signal between the moment of the last positioning echo and the moment of the liquid surface echo is recorded as the liquid surface echo signal.

4. A method for real-time monitoring of liquid level of a steam gas-liquid separator as claimed in claim 1, characterized in that: The electromagnetic average speed of each positioning echo signal is the product of the length of each positioning echo signal, the preset sampling frequency and the interval between adjacent positioning points.

5. The method for real-time monitoring of liquid level of a steam gas-liquid separator according to claim 1, characterized in that: The velocity distribution weight of each positioning echo signal is a normalized value of the similarity between each positioning echo signal and the liquid surface echo signal.

6. A method for real-time monitoring of liquid level of a steam gas-liquid separator as claimed in claim 1, characterized in that: The velocity correction term of the electromagnetic wave is the cumulative sum of the products of the velocity distribution weights of all positioning echo signals and the corresponding electromagnetic average velocity.

7. A method for real-time monitoring of liquid level of a steam gas-liquid separator as claimed in claim 1, characterized in that: The method for determining the speed correction weight of the electromagnetic wave is: Calculate the coefficient of variation of all elements in the electromagnetic echo signal. If the coefficient of variation is less than 1, the velocity correction weight of the electromagnetic wave is equal to the coefficient of variation. Otherwise, the velocity correction weight of the electromagnetic wave is equal to 1.

8. A method for real-time monitoring of liquid level of a steam gas-liquid separator as claimed in claim 7, characterized in that: The expression of the distance between the positioning point corresponding to the last positioning echo moment and the steam gas-liquid level is: ; In the formula, Indicates the distance between the positioning point corresponding to the last positioning echo moment and the steam gas-liquid level; Indicates the length of the liquid surface echo signal; F indicates the preset sampling frequency.

9. A method for real-time monitoring of liquid level of a steam gas-liquid separator as claimed in claim 8, characterized in that: The expression of the liquid level height of the steam gas-liquid separator at the current moment is: ; In the formula, Indicates the liquid level of the steam gas-liquid separator at the current moment; It represents the distance from the electromagnetic wave emission position to the bottom of the steam gas-liquid separator; H represents the number of all positioning points on the waveguide rod; d represents the interval between adjacent positioning points.

10. A steam gas-liquid separator, comprising a memory, a processor, and a computer program stored in the memory and running on the processor, characterized in that: When the processor executes the computer program, the steps of a method for real-time monitoring of liquid level of a steam-gas-liquid separator as described in any one of claims 1-9 are implemented.

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