A method and device for determining a two-phase interface

Abstract

The present invention relates to the technical field of determining the position of a two-phase interface, and more specifically to a method and device for determining a two-phase interface. By reading and recording the refractive index value measured and displayed by an in-situ online refractometer, the position of the interface between two liquids of different phases in a liquid separation tank is determined. The device for determining the two-phase interface provided by the present invention has a simple and clear structure, does not require major improvements to the liquid separation tank, and has a simple installation process. It only requires fixing the light source to the top or bottom of the light source, and ensuring that the light source and the detection component can be correctly aligned with the liquid to be measured. The axis of the detection component is located in the horizontal direction and can be inserted into different liquid levels of the liquid separation tank. Through this principle, the online refractometer can measure the refractive index of the liquid in real time online, thereby obtaining the liquid level information of the liquid. This measurement method is fast, accurate, and continuous, and is very suitable for occasions where the liquid position needs to be monitored in real time.

Description

Technical Field

[0001] The present invention relates to the technical field of determining the position of a two-phase interface, and more particularly to a method and a device for determining the two-phase interface. Background Art

[0002] In fields such as chemical engineering, petroleum, and food, interfacial issues between different phases (e.g., liquid, gas, and solid) are often addressed. Accurately determining the location of interphases has always been a critical issue in both practical production and research. For example, in oil extraction, the position of the oil-water interface significantly impacts extraction efficiency and separation effectiveness. In food processing, the position of interfaces between different liquids also directly influences product quality and taste.

[0003] Density-based float level gauge is a common liquid level measuring instrument. Its working principle is to use the buoyancy principle and the lever principle to measure the liquid level and distinguish the interface between two phases. The float level gauge usually consists of a float, a lever, an indicator and a bracket. When used to measure the liquid level, the float of the float level gauge is made of a material with a density lower than that of the liquid being measured. When the liquid level rises, the float will rise with the liquid level and the position of the float will change accordingly (please refer to the attached Figure 1 ). The change in the float's position is transmitted to the indicator via a lever, thereby displaying the liquid level.

[0004] In chemical unit operations, density-based float level gauges are often used to distinguish the interface between two phases or separate two liquid phases. The density of the float is between the density of the lower liquid phase and the density of the upper liquid phase, and it floats on the lower liquid phase. For example, in the separation of water and cyclohexane, the density of water at room temperature is 1.0 g / cm 3 , the density of cyclohexane is 0.78 g / cm 3 The density of the float ball can be 0.89g / cm 3 The float level gauges on the left and right are based on the buoyancy principle. The floats can float on the two-phase boundary of water and cyclohexane. During chemical operations, the first and second liquid phases can be separated through the liquid phase discharge control valve operated by the interface.

[0005] However, the float level gauge mentioned above is sometimes ineffective in separating two liquid phases. For some special materials, the densities of the two liquid phases are relatively close, such as propylene glycol methyl ether acetate (PMA) and water. The density of propylene glycol methyl ether acetate (PMA) at room temperature is 0.97 g / cm 3 , the density difference from water at room temperature is only 0.03g / cm 3 If the float density is 0.985g / cm 3 The float level gauge has a density difference of 0.015 g / cm2 with both propylene glycol methyl ether acetate (PMA) and water. 3, and it cannot guarantee that the interface meter can work properly. Because in the process of chemical operation, the temperature often changes, sometimes the temperature is high, sometimes the temperature is low. For example, the density of water at room temperature is 1.0g / cm 3 However, at 80°C, the density of water drops to 0.97 g / cm 3 At this time, the density of the float is 0.985g / cm 3 The float of the float level gauge will sink to the bottom of the water, causing production accidents.

[0006] Clearly, density-based float level sensors face technical bottlenecks in distinguishing and separating two liquid phases at the interface under temperature fluctuations. Furthermore, existing methods for determining the position of the interface, such as estimating using physical parameters like buoyancy and interfacial tension, or performing laboratory measurements after sampling, are subject to errors and inconvenience. Therefore, a method and device that can accurately measure the position of the interface in real time, online, and on-site is urgently needed. Summary of the Invention

[0007] To this end, it is necessary to provide a method and device for determining the two-phase interface to break through the technical bottleneck of the density-based float level meter in distinguishing and separating the two liquid phases caused by temperature changes, and at the same time provide a new and simple interface device to meet the needs of chemical operation units to determine the position of the two-phase interface in real time, online and accurately.

[0008] To achieve the above objectives, in a first aspect, the present invention provides a method for determining a two-phase interface, comprising the following steps:

[0009] A plurality of in-situ online refractometers are arranged at equal intervals from the liquid surface on the liquid separation tank, and the in-situ online refractometers are used to measure and display the light refractive index values ​​corresponding to the liquid levels in the liquid separation tank;

[0010] Keeping the temperature and state of the liquid at the two-phase interface to be determined stable, reading and recording the light refractive index values ​​on each of the in-situ online refractometers;

[0011] According to the light refractive index values ​​read and recorded, searching for two adjacent in-situ online refractometers with different light refractive index values;

[0012] It is determined that the two-phase interface to be determined is located between two adjacent in-situ online refractometers having different light refractive index values.

[0013] According to some preferred embodiments, the plurality of in-situ online refractometers is 6-12. It is readily understood that since the two-phase interface is determined based on the refractive index values ​​read by two adjacent in-situ online refractometers, the greater the number of in-situ online refractometers, the closer the spacing between them, and the more accurate the interface location can be.

[0014] In some preferred embodiments, the method further includes the step of determining the maximum liquid level in the upper layer. Depending on specific practical needs, the maximum liquid level in the upper layer may also dynamically change as the storage state in the liquid separation tank changes. Based on the refractive index values ​​of two different in-situ online refractometers located in the upper layer of the liquid separation tank, the interface between the upper gas phase and the upper liquid phase of the liquid separation tank can be determined. The maximum liquid level value also needs to be read and recorded to provide guidance for the next step.

[0015] According to some preferred embodiments, the equidistant liquid level interval is 5-10 cm, with an appropriate interval selected based on actual needs. Of course, a smaller equidistant liquid level interval means a closer spacing between the in-situ online refractometers. A greater number of in-situ online refractometers requires, and a more precise interface location can be determined.

[0016] In a second aspect, the present invention provides a device for determining a two-phase interface, which is applied to the method for determining a two-phase interface described in the first aspect of the present invention, comprising:

[0017] Liquid separation tank, used to hold liquids with different phase interfaces to be determined;

[0018] A plurality of in-situ online refractometers, each of the in-situ online refractometers comprises a detection component, and the plurality of detection components are connected to different liquid levels of the liquid separation tank;

[0019] a first control valve, for controlling the first liquid phase to flow out of the liquid separation tank;

[0020] and a second control valve for controlling the second liquid phase to flow out of the liquid separation tank.

[0021] The in-situ online refractometer described in the present invention is a common online refractometer on the market, and is often used in the fields of environmental protection, agriculture, renewable energy, biotechnology, etc. to perform real-time monitoring of substance concentrations.

[0022] According to some preferred embodiments, the device for determining the two-phase interface further includes a PLC control system, and the in-situ online refractometer, first control valve, and second control valve are all electrically connected to the PLC control system to enable precise control and data acquisition. Because the in-situ online refractometer is directly connected to the liquid separation tank, the PLC control system can collect the refractive index value corresponding to each liquid level in real time and display it on the PLC control system panel. Furthermore, the first and second control valves are electrically connected to the PLC control system, and by upgrading the control function module of the PLC control system, intelligent control of the outflow volume and outflow rate of the first and / or second liquid phases can be achieved.

[0023] In some preferred embodiments of the present invention, the axis of the detection component is located in the horizontal direction so as to be inserted into different liquid levels of the liquid separation tank. The detection component of the in-situ online refractometer includes a light source, an optical window, an optical fiber, a prism, a CCD plate, a CCD sensor, etc., which form a whole with a detection function in a specific structure. The whole is connected to a preset position on the side wall of the liquid separation tank by insertion, screwing in, or snapping, and is used to detect and output the refractive index value corresponding to the liquid at that position. Therefore, the axis of the detection component is located in the horizontal direction, which can ensure that the corresponding liquid phase level value is accurate.

[0024] In some preferred embodiments of the present invention, the detection component includes an optical window made of sapphire or a mineral material and a temperature detector. This allows the detection component to achieve more stable optical performance, ensuring the transmission of the light beam. Furthermore, sapphire's corrosion resistance broadens its applicability when monitoring or analyzing corrosive liquid phases. Furthermore, its high hardness and wear resistance enhance the detection component's effectiveness and lifespan.

[0025] In some preferred embodiments of the present invention, each of the in-situ online refractometers is connected to different liquid levels in the liquid separation tank at predetermined intervals. As described above, each in-situ online refractometer is connected to a predetermined location on the sidewall of the liquid separation tank by insertion, screwing, or snapping. The liquid phase at each predetermined location has a specific refractive index for specific light due to the liquid's inherent properties. The in-situ online refractometer collects the refractive index of the liquid phase at each predetermined location, and comparison allows for easy determination of the location of the liquid two-phase interface.

[0026] The range and accuracy of the liquid interface position determined using the above method are closely related to the preset liquid level interval. The smaller the preset liquid level interval, the more accurate the measured liquid interface position, and accordingly, the denser the in-situ refractometers can be deployed. Considering the inherent size of the in-situ refractometer, in some preferred embodiments of the present invention, the preset liquid level interval is 5-10 cm.

[0027] A refractometer is an instrument used to measure the refractive index of a substance. Its working principle is based on the phenomenon of refraction of light and Snell's law. By measuring the angle of refraction and the angle of incidence of light in different media, the refractive index of a substance can be determined. When light propagates from one medium to another, it will refract due to the difference in optical density between the media. Refraction refers to the phenomenon that light changes its propagation direction when passing through the interface between two media. This phenomenon is caused by the different propagation speeds of light in different media. Snell's law is a law that describes the law of refraction of light when it propagates between two media. Snell's law shows that when light passes through the interface between two media, there is a relationship between the angle of incidence, the angle of refraction and the refractive index of the two substances, namely:

[0028] n1*sin(θ1)=n2*sin(θ2)

[0029] Here, n1 and n2 are the refractive indices of the two media, and θ1 and θ2 are the angles of incidence and refraction, respectively. A refractometer typically consists of a light source, a collimator, a measuring device, a degree dial, a measuring screw, and an eyepiece. The light source is typically an incandescent lamp or a light bulb, with the collimator parallelizing the light. The measuring device consists of two translucent parallel surfaces with an adjustable angle between them. The degree dial is used to measure the angle, and the measuring screw is used to adjust the angle. The eyepiece is used to observe the refraction of light. With the advancement of technology, in-situ online refractometers have emerged.

[0030] The present invention uses Vaisala Polaris produced by Vaisala (Beijing) Measurement Technology Co., Ltd. TM The PR53GP online refractometer's main components include a light source, optical fiber, detector, and computer. When light from the light source is transmitted through the optical fiber to the detector, the detector measures the light's propagation speed and direction and transmits this data to the computer for processing. The computer then calculates the liquid's refractive index based on Snell's law and displays the result on a screen. Directly mounted on a liquid separation tank, the online refractometer, based on Snell's law, eliminates the need to drop a sample of the liquid to be measured. This allows for real-time, accurate, and continuous measurement of the liquid's refractive index, thereby providing information on the liquid's density. This fast, accurate, and continuous measurement method is ideal for applications requiring real-time monitoring of liquid levels, such as on-line production lines. Importantly, because this technical solution utilizes an online refractometer based on light refraction and Snell's law, it is not limited by the similar densities of two adjacent liquid phases. This approach significantly improves the traditional practice of using float level gauges to determine the interface between two liquid phases, greatly facilitating the identification of the interface and specific separation and extraction operations for chemical unit operators.

[0031] Unlike existing technologies, this solution determines the location of the interface between two different liquid phases in a liquid separation tank by reading and recording the refractive index values ​​measured and displayed by an in-situ online refractometer. Furthermore, based on the determined location of the interface, either the first or second control valve is opened as needed to separate and extract one of the liquid phases. This simple and easy method accurately and in real time provides the location of the interface between the two phases, without causing temperature fluctuations to cause density changes between the two phases, or similar densities between the two phases to cause the float level gauge to sink to the bottom and fail.

[0032] The device for determining the two-phase interface provided by the present invention has a simple and clear structure, does not require major improvements to the liquid separation tank, and has a simple installation process. It only requires the detection component of the online refractometer to be connected to the side wall of the liquid separation tank by insertion, screwing in, or snapping in, and ensuring that the light source and the detection component can be correctly aligned with the liquid to be tested. The main components of the in-situ online refractometer include a light source, an optical fiber, a detector, and a computer. When the light emitted by the light source is transmitted to the detector through the optical fiber, the detector measures the propagation speed and direction of the light and transmits the data to the computer for processing. The computer calculates the refractive index of the liquid based on Snell's law and displays the result on the screen.

[0033] Using this principle, an online refractometer can measure the refractive index of a liquid in real time, thereby obtaining liquid level information. This measurement method is fast, accurate, and continuous, making it ideal for applications requiring real-time monitoring of liquid position.

[0034] The above-mentioned records related to the content of the invention are only an overview of the technical solution of this application. In order to enable ordinary technicians in this field to understand the technical solution of this application more clearly, and then implement it according to the text of the specification and the contents recorded in the drawings, and to make the above-mentioned purposes and other purposes, features and advantages of this application easier to understand, the following is an explanation in combination with the specific implementation methods and drawings of this application. BRIEF DESCRIPTION OF THE DRAWINGS

[0035] Figure 1 This is a schematic diagram of the operating state of a float level gauge commonly used in the prior art for determining and separating two liquid phases;

[0036] Figure 2 Schematic diagram of the structure of the device for determining the liquid two-phase interface in the present invention;

[0037] Figure 3 Schematic diagram of the device for determining the liquid two-phase interface and its operating state in the present invention;

[0038] Figure 4 for Figure 3 A in the middle is an enlarged schematic diagram;

[0039] Figure 5 Schematic diagram of the process of determining the two-phase interface of the present invention.

[0040] Description of reference numerals:

[0041] 1. Liquid separation tank; 2. In-situ online refractometer; 3. First control valve; 4. Second control valve; 5. PLC control system; 6. Optical window; 7. Temperature detector. DETAILED DESCRIPTION

[0042] In order to explain the technical content, structural features, achieved objectives and effects of the technical solution in detail, the following is a detailed description in conjunction with specific embodiments and accompanying drawings.

[0043] References to "embodiments" herein mean that the specific features, structures, or characteristics described in conjunction with the embodiments may be included in at least one embodiment of the present application. The appearance of the word "embodiment" in various places in the specification does not necessarily refer to the same embodiment, nor does it particularly limit its independence or relevance to other embodiments. In principle, in this application, as long as there are no technical contradictions or conflicts, the various technical features mentioned in the embodiments can be combined in any manner to form a corresponding implementable technical solution.

[0044] Unless otherwise defined, the technical terms used herein have the same meanings as those generally understood by those skilled in the art to which this application belongs; the use of relevant terms herein is only for describing specific embodiments and is not intended to limit this application.

[0045] In the description of this application, the term "and / or" is used to describe a logical relationship between objects, indicating that three relationships can exist. For example, A and / or B means: A exists, B exists, and both A and B exist. In addition, the character " / " in this document generally indicates that the objects before and after are in a logical "or" relationship.

[0046] In this application, terms such as "first" and "second" are merely used to distinguish one entity or operation from another entity or operation, and do not necessarily require or imply any actual quantity, priority or sequence relationship between these entities or operations.

[0047] Without further limitations, in this application, the words "include", "comprise", "have" or other similar expressions used in the sentences are intended to cover non-exclusive inclusion. These expressions do not exclude the presence of additional elements in the process, method or product including the elements, so that the process, method or product including a series of elements may include not only those defined elements, but also other elements not explicitly listed, or elements inherent to such process, method or product.

[0048] Consistent with the understanding in the Patent Examination Guidelines, in this application, expressions such as "greater than," "less than," and "exceed" are understood to exclude the number itself; expressions such as "above," "below," and "within" are understood to include the number itself. In addition, in the description of the embodiments of this application, "multiple" means more than two (including two), and similar expressions related to "multiple" are also understood in this manner, such as "multiple groups" and "multiple times," unless otherwise clearly and specifically limited.

[0049] In the description of the embodiments of the present application, the space-related expressions used, such as "center", "longitudinal", "lateral", "length", "width", "thickness", "up", "down", "front", "back", "left", "right", "vertical", "horizontal", "vertical", "top", "bottom", "inside", "outside", "clockwise", "counterclockwise", "axial", "radial", "circumferential", etc., indicate the orientation or position relationship based on the orientation or position relationship shown in the specific embodiments or drawings, and are only for the convenience of describing the specific embodiments of the present application or facilitating the reader's understanding, and do not indicate or imply that the device or component referred to must have a specific position, a specific orientation, or be constructed or operated in a specific orientation. Therefore, it should not be understood as a limitation on the embodiments of the present application.

[0050] Unless otherwise expressly specified or limited, in the description of the embodiments of the present application, the terms "installed", "connected", "connected", "fixed", "set", etc. used should be understood in a broad sense. For example, the "connection" can be a fixed connection, a detachable connection, or an integrated setting; it can be a mechanical connection, an electrical connection, or a communication connection; it can be a direct connection or an indirect connection through an intermediate medium; it can be the internal connection of two elements or the interaction relationship between two elements. For those skilled in the art of the present application, the specific meanings of the above terms in the embodiments of the present application can be understood according to the specific circumstances.

[0051] like Figure 2 As shown, the device for determining the two-phase interface of the present invention includes a liquid separation tank 1, an in-situ online refractometer 2, a first control valve 3 and a second control valve 4. The liquid separation tank 1 is used to hold liquids with different phase boundaries to be determined. The in-situ online refractometer 2 is used to measure and display the light refractive index value corresponding to the liquid level in the liquid separation tank 1. A plurality of in-situ online refractometers 2 are arranged on the liquid separation tank 1 at equal distances from the liquid surface. The first control valve 3 and the second control valve 4 are used to control the outflow of different liquid phases. The PLC control system 5 is used to control and collect data. The axis of the detection component is located in the horizontal direction to facilitate insertion into different liquid levels of the liquid separation tank. Please refer to Figure 4 As shown, it is Figure 3A magnified view of Figure A in Figure 1 shows the detection component of the online refractometer, which extends into the liquid separation tank. This component includes an optical window 6 made of sapphire or mineral material and a temperature detector 7, enabling more accurate refractive index and temperature measurements. The detection component also includes a conventional light source, optical fiber, prism, CCD panel, and CCD sensor, forming the entire detection component. The component is connected to a preset location on the sidewall of the liquid separation tank by insertion, screwing, or snapping, to detect and output the corresponding refractive index value of the liquid at that location. Therefore, the axis of the detection component is horizontal, ensuring accurate liquid level values. The refractometer is connected to different liquid levels in the liquid separation tank at preset distances and level intervals. The size and accuracy of the liquid interface position determined using the above method are closely related to the preset distance and level intervals. The smaller the preset distance and level interval, the more accurate the measured liquid interface position, and accordingly, the denser the in-situ online refractometers can be deployed. Considering the inherent size of the in-situ online refractometer, the preset distance and level interval is 5-10 cm.

[0052] See also Figure 5 The flow chart of the method for determining the two-phase interface of the present invention is shown in FIG. The method for determining the two-phase interface of the present invention comprises the following steps:

[0053] See also Figure 3 , the liquid separation tank where the interface between the two liquid phases is to be determined is filled with an appropriate amount of propylene glycol methyl ether acetate (PMA) and water. Due to the different properties of the two liquids, they automatically separate into two layers after standing in the liquid separation tank, the upper layer is propylene glycol methyl ether acetate (PMA), and the lower layer is water. A number of in-situ online refractometers are set at equal distances from the liquid surface on the liquid separation tank, and the detection components of the in-situ online refractometers are connected to the side wall of the liquid separation tank by insertion, screwing in or snapping. The side wall of the tank can be pre-opened with light-transmitting holes. These in-situ online refractometers are adjusted and calibrated one by one to keep the temperature and state of the liquid at the two-phase interface to be determined stable. Read and record the temperature and refractive index values ​​on each in-situ online refractometer. For example, at 25°C, the refractive index of propylene glycol methyl ether acetate is 1.399, and the refractive index of water is 1.333. Based on the read and recorded refractive index values, it can be found that Figure 3 In the left figure, from bottom to top, the refractive index values ​​on the 1st to 3rd online refractometers are all 1.333, and the refractive index values ​​on the 4th to 10th online refractometers are all 1.399. Therefore, the liquid levels corresponding to the two adjacent in-situ online refractometers with different light refractive index values ​​(i.e., the liquid levels corresponding to the 3rd and 4th online refractometer detection components) are the locations of the two-phase interface between propylene glycol methyl ether acetate and water. As the chemical operation proceeds, if the propylene glycol methyl ether acetate (PMA) and water in the liquid separation tank are in Figure 3As shown in the right figure, when the liquid levels of the two are stable under the temperature conditions, it can be found that the refractive index values ​​on the 1st to 5th online refractometers from the bottom up are all 1.333, while the refractive index values ​​on the 6th to 10th online refractometers are all 1.399. Therefore, it can be determined that the liquid levels corresponding to the two adjacent in-situ online refractometers with different refractive index values ​​at this moment (i.e., the liquid levels corresponding to the 5th and 6th online refractometer detection components) are the locations of the two-phase interface between propylene glycol methyl ether acetate and water.

[0054] The following steps can be used to operate the in-situ online refractometer:

[0055] Installation equipment: Vaisala Polaris TM The PR53GP online refractometer is mounted on a separator tank. Ensure the device is positioned to accurately measure the refractive index of the two-phase liquid. Depending on the model and design of the device, a specific mounting bracket or adapter may be required.

[0056] Start the device: Turn on the power of the online refractometer to start the device. The device may perform a self-test or initialization process to ensure normal operation.

[0057] Calibrate the device: Calibrate the online refractometer according to the calibration requirements of the device. This may include calibration with standard liquids or using the calibration tool that comes with the device.

[0058] Measuring refractive index: After the two-phase liquid interface stabilizes, the refractive index is measured. The refractive index value can be read through the PLC system control panel or a connected computer.

[0059] Finding interfaces: Find the interface between two phases of liquid based on changes in refractive index. Usually, there will be a significant change in refractive index at the interface, allowing the location of the interface to be determined.

[0060] Record data: Record the measured refractive index data, including data at different time points. This data can be used for further analysis and processing.

[0061] Turn off the device: After completing the measurement, turn off the power of the online refractometer to end the operation.

[0062] Of course, the method and apparatus of the present invention are also applicable to determining the interface of a mixture of immiscible liquid and gas phases.

[0063] The device and method of the present invention, which combines an online refractometer with a liquid separation tank, replaces the traditional practice of using a float interface gauge to measure two-phase liquid levels based on density differences. Instead, the device locates the liquid level using the inherent refractive index differences of the media, unrestricted by the magnitude of the density differences. In chemical raw material feeding and addition operations, which frequently require temperature changes, the device eliminates issues such as the float interface gauge sinking to the bottom or interface determination failure caused by a small density difference between the two phases due to temperature fluctuations. This significantly improves the convenience, effectiveness, and accuracy of chemical operations.

[0064] It should be noted that although the above embodiments have been described herein, this does not limit the scope of patent protection of the present invention. Therefore, based on the innovative concept of the present invention, changes and modifications to the embodiments described herein, or equivalent structural or equivalent process transformations made using the contents of the present invention's specification and drawings, and direct or indirect application of the above technical solutions to other related technical fields, are all included in the scope of patent protection of the present invention.

Claims

1. A method for determining a two-phase interface, characterized in that: The steps include: A plurality of in-situ online refractometers are arranged at equal intervals from the liquid surface on the liquid separation tank, and the in-situ online refractometers are used to measure and display the light refractive index values ​​corresponding to the liquid levels in the liquid separation tank; Keeping the temperature and state of the liquid at the two-phase interface to be determined stable, reading and recording the light refractive index values ​​on each of the in-situ online refractometers; According to the light refractive index values ​​read and recorded, searching for two adjacent in-situ online refractometers with different light refractive index values; It is determined that the two-phase interface to be determined is located between two adjacent in-situ online refractometers having different light refractive index values.

2. The method according to claim 1, characterized in that The number of the multiple in-situ online refractometers is 6-12.

3. The method according to claim 1, characterized in that The method also includes the step of determining a maximum level of the liquid in the upper layer.

4. The method according to claim 1, wherein The equidistant liquid level interval is 5-10 cm.

5. A device for determining a two-phase interface, applied to the method for determining a two-phase interface according to any one of claims 1 to 4, characterized in that: include: Liquid separation tank, used to hold the liquid whose two-phase interface is to be determined; A plurality of in-situ online refractometers, each of the in-situ online refractometers comprises a detection component, and the plurality of detection components are connected to different liquid levels of the liquid separation tank; a first control valve, for controlling the first liquid phase to flow out of the liquid separation tank; and a second control valve for controlling the second liquid phase to flow out of the liquid separation tank.

6. The device according to claim 5, characterized in that It also includes a PLC control system, and the in-situ online refractometer, the first control valve and the second control valve are all electrically connected to the PLC control system.

7. The device according to claim 5, characterized in that The axis of the detection component is located in a horizontal direction so as to be inserted into different liquid levels of the liquid separation tank.

8. The device according to claim 5, characterized in that The detection component comprises an optical window made of sapphire or mineral material and a temperature detector.

9. The device according to claim 5, characterized in that Each of the refractometers is connected to a different liquid level of the liquid separation tank at a preset distance interval.

10. The device according to claim 9, characterized in that The preset distance liquid level interval is 5-10 cm.

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