Oil-water detector and method based on liquid mass resonance measurement principle

Abstract

The invention relates to the technical field of oil-water detection equipment, and discloses an oil-water detector and method based on a liquid mass resonance measurement principle. The oil-water detector based on the liquid mass resonance measurement principle comprises a parameter sensing unit which is used for contacting an oil-water mixed medium in a pipeline and comprises a current carrying body with a measurement cavity, a measurement probe arranged in the measurement cavity and a resonance body arranged in the measurement probe; and the data processing unit is in signal connection with the parameter sensing unit and comprises a signal transmitting module which is used for transmitting an audio frequency sweep frequency signal to the resonant body to excite liquid column resonance and transmitting electromagnetic short waves with a preset frequency to an oil-water mixed medium at the same time. According to the invention, direct measurement of the density and the dielectric constant is fused, the phase state is identified by using an intelligent algorithm, and the model is switched, so that the problem of failure of a single principle technology in a specific phase state is solved, and high-precision measurement in a water-in-oil state or an oil-in-water state in a full range from pure water to pure oil is realized.

Description

TECHNICAL FIELD

[0001] The present application relates to the technical field of oil-water detection equipment, more particularly, it relates to an oil-water detector and method based on liquid quality resonance measurement principle. BACKGROUND

[0002] In the process of oil exploitation, storage and transportation, and processing, crude oil or products inevitably contain moisture. In order to realize oil-water separation, sedimentation tanks, separators and other equipment are usually used. The water phase (oily sewage) after separation needs to be discharged in time (i.e. "cut water"), and the oil phase needs to be further dehydrated and purified. Therefore, real-time and accurate online detection of oil in water (or water in oil) and automatic control of the dehydration process according to the detection are of great significance to ensure oil quality, improve production efficiency, save energy and prevent environmental pollution.

[0003] At present, the common online oil-water detection technology on the market mainly includes detection methods based on a single physical principle, such as: Capacitance method / radio frequency method: the water content is inferred by measuring the change of dielectric constant of the medium; this method is sensitive to trace water changes in the water-in-oil (water phase dispersed) state because the dielectric constant of water is much larger than that of oil; however, when the medium is in the oil-in-water (oil phase dispersed) state or the oil-water density is close (such as heavy crude oil), the change of dielectric constant is not obvious, resulting in a sharp decrease in measurement accuracy, and even failure; density method / vibration method: the oil content is calculated by measuring the change of density of the medium; this method is effective in the oil-in-water state, but in the oil-in-water state, especially when the oil content is high, the density change range is small, the sensitivity is low, and it is difficult to achieve high-precision measurement; optical method: it is easily affected by medium bubbles, impurities and pipe wall scaling, has high maintenance cost, and has poor stability under complex working conditions.

[0004] The above-mentioned detection technology based on a single principle has certain limitations, and the precision and stability exhibited in the full phase state (water-in-oil and oil-in-water) and full range are not ideal; therefore, a new detection technology that can simultaneously sense multiple physical parameters of the medium and intelligently adapt to different mixed phases is urgently needed. SUMMARY

[0005] The present application provides an oil-water detector and method based on liquid quality resonance measurement principle, which solves the above-mentioned technical problems.

[0006] The present application solves the above-mentioned technical problems by the following technical solutions: The present application provides an oil-water detector based on liquid quality resonance measurement principle, comprising: A parameter sensing unit for contacting the oil-water mixed medium in the pipeline, which comprises a carrier fluid having a measurement cavity, a measurement probe arranged in the measurement cavity, and a resonance body built in the measurement probe; The data processing unit is connected with the parameter sensing unit and comprises: The signal transmitting module is configured to transmit an audio frequency sweep signal to the resonant body to excite the liquid column resonance and simultaneously transmit electromagnetic short waves of a predetermined frequency to the oil-water mixed medium. The signal collecting module is configured to collect the resonant frequency signal of the resonant body and the absorption attenuation signal of the electromagnetic short waves. The data processing module is configured to calculate the density parameter of the medium according to the resonant frequency signal, calculate the dielectric constant parameter of the medium according to the absorption attenuation signal, identify the phase state of the medium based on the density parameter and the dielectric constant parameter, select a corresponding calculation model according to the identification result, and output the oil content value in water.

[0007] Preferably, the specific logic of the data processing module for identifying the phase state of the medium comprises: calculating the change amount ratio of the dielectric constant parameter and the density parameter within a unit time, and determining that the medium is in the water-in-oil phase when the ratio is greater than a preset threshold, otherwise determining that the medium is in the oil-in-water phase.

[0008] Preferably, the data processing module pre-stores a first calculation sub-model corresponding to the water-in-oil phase and a second calculation sub-model corresponding to the oil-in-water phase; when the oil-in-water phase is identified, the first calculation sub-model is called and fitting calculation is mainly performed according to the dielectric constant parameter; when the oil-in-water phase is identified, the second calculation sub-model is called and fitting calculation is mainly performed according to the density parameter.

[0009] Preferably, the data processing unit further comprises a wireless communication module for wirelessly connecting with an external handheld debugging terminal to receive an adjustment instruction for the translation coefficient and / or the elevation angle coefficient in the calculation model.

[0010] Preferably, the outer surface of the measurement probe is coated with a nano Teflon anti-adhesion coating, and the measurement probe is electrically connected with the data processing unit through an automatic latch structure.

[0011] Preferably, the parameter sensing unit and the data processing unit are integrated in the same explosion-proof shell to form an integrated structure.

[0012] Preferably, the explosion-proof shell is provided with a sealing connecting body for detachably connecting the parameter sensing unit and the measurement pipeline.

[0013] Preferably, the data processing unit further comprises a display module for displaying the oil content value in water and / or the change curve in real time.

[0014] Preferably, the predetermined frequency of the electromagnetic short waves transmitted by the signal transmitting module is 4 MHz.

[0015] An oil-water detection method comprises the following operation steps: S100: make the oil-water mixed medium to be measured flow through the measurement cavity of the parameter sensing unit; S200: synchronously emit the audio frequency sweep signal and the electromagnetic short wave of the predetermined frequency through the signal emitting module; S300: synchronously collect the resonance frequency signal and the absorption attenuation signal through the signal collecting module; S400: execute the phase state recognition and the oil content calculation logic through the data processing module to output the oil content value in water.

[0016] The present application has the advantages that: The present application overcomes the problem that the single principle technology fails in a specific phase state by fusing the direct measurement of density and dielectric constant and using intelligent algorithm to recognize the phase state and switch the model, and realizes high-precision measurement in the full range from pure water to pure oil, whether in the water-in-oil or oil-in-water state. In addition, the liquid column resonance used in the present application is sensitive to density, and the short wave absorption is sensitive to dielectric constant, the two mechanisms are different, the interference influence trends of the common properties such as medium temperature, viscosity and bubbles may be different, and through the dual parameter fusion analysis, they can be mutually checked and compensated, effectively suppressing the interference and improving the precision and stability of the measurement. BRIEF DESCRIPTION OF DRAWINGS

[0017] Fig. 1 is a structural schematic diagram of an oil-water detector based on the liquid quality resonance measurement principle of the present application; Fig. 2 is a state schematic diagram of the oil-water detector based on the liquid quality resonance measurement principle of the present application in use; Fig. 3 is a structural block diagram of the oil-water detector based on the liquid quality resonance measurement principle of the present application; Fig. 4 is a work flow diagram of an oil-water detection method of the present application.

[0018] In the figure: 10, parameter sensing unit; 101, carrier fluid; 102, measurement probe; 103, resonance body; 104, measurement cavity; 105, flow guide groove; 20, data processing unit; 30, sealing connecting body. DETAILED DESCRIPTION

[0019] The subject matter described herein will now be discussed with reference to example implementations. It should be understood that the discussion of these implementations is merely meant to provide a better understanding of the subject matter described herein and can be changed in function and arrangement without departing from the scope of the present specification. Various processes or components can be omitted, substituted, or added according to different examples. In addition, features described with respect to some examples can be combined in other examples.

[0020] Please refer to Figs. 1 to 4 The oil-water detector designed by the application is mainly realized based on the liquid quality resonance measurement principle. The appearance is a solid one-piece explosion-proof shell made of stainless steel. All electronic components are integrated in the explosion-proof shell. One end of the explosion-proof shell is a parameter sensing unit 10, which includes a current-carrying body 101 made of Monel alloy. The current-carrying body 101 is internally processed with a columnar measuring cavity 104 of precise size. The cavity side is provided with a spiral flow guide groove 105 to ensure that the fluid fully contacts the probe. The cavity center is fixed with a measuring probe 102, which is a high-Q titanium alloy resonator 103. The working surface of the measuring probe 102 is uniformly coated with a nano Teflon coating about 0.1 mm thick. The tail of the measuring probe 102 is quickly plugged with the circuit board in the shell through a group of gold-plated elastic pins (constituting an automatic latch structure).

[0021] The other end of the explosion-proof shell is the installation area of the data processing unit 20. The signal transmitting module, signal collecting module, display module and data processing module are integrated in the explosion-proof shell. The signal transmitting module includes a DDS (direct digital frequency synthesis) chip for generating a 10 kHz-100 kHz audio frequency sweep signal to drive the resonator 103. At the same time, a dedicated oscillation circuit generates a stable 4 MHz sine wave as an electromagnetic short wave transmitting source. The signal collecting module includes a high-precision frequency counter and a radio frequency detection circuit, which are used to capture the resonance frequency and measure the decay amplitude of the 4 MHz signal, respectively. The data processing module takes an embedded microprocessor as the core. The phase state recognition threshold K, the first calculation sub-model (polynomial coefficient set Coef OilContinuous ) and the second calculation sub-model (polynomial coefficient set Coef WaterContinuous ) are stored in the internal Flash. The microprocessor runs the phase state recognition and adaptive calculation program in real time. The wireless communication module uses SI4463 chip to realize 470 MHz wireless communication. The display module is a small OLED display screen embedded in the window of the explosion-proof shell.

[0022] In addition, a sealing connecting body 30 is arranged on the explosion-proof shell near the parameter sensing unit 10. The sealing connecting body 30 is detachably connected with the flange seat on the pipeline through a gasket to realize the effective connection between the detector and the measuring pipeline.

[0023] The working process of the oil-water detector based on the liquid quality resonance measurement principle designed by the application is as follows: Step one, when the instrument is powered on, the medium (such as oilfield produced water) flows through the measuring cavity 104, the signal transmitting module starts sweep and 4MHz transmission synchronously, and the signal collecting module sends the collected original signal (frequency value f, voltage value V) to the data processing module.

[0024] Step two, the microprocessor first performs a scaling transformation according to the following formula: D = A1 x f + B1, wherein A1, B1 are density calibration coefficients; E = A2 x V + B2, wherein A2, B2 are dielectric constant calibration coefficients, the above A1, B1, A2, B2, K model coefficients are obtained through laboratory calibration, and can be fine-tuned on site through instructions received by the wireless communication module.

[0025] Step three, then, phase recognition is performed, the microprocessor calculates a group of D and E every 1 second, and calculates the ratio R = |ΔE 5s | / |ΔD 5s | of the change amount of E and D in the past 5 seconds, the preset threshold K is set to 3.0 through experiments at the factory, if R>3.0, it is determined as water-in-oil phase; if R≤3.0, it is determined as oil-in-water phase.

[0026] Step four, then, adaptive calculation is performed: if it is oil-in-water phase, a first calculation sub-model is called: Oil Content = CoefOil Continuous [0] + Coef OilContinuous [1] x E + Coef OilContinuous [2] x E 2 +… (the model takes E as the main input, and D as a correction term or for verification); if it is oil-in-water phase, a second calculation sub-model is called: Oil Content = Coef WaterContinuous [0] + Coef WaterContinuous [1] x D + Coef WaterContinuous [2] x D 2 +… (the model takes D as the main input); The calculated Oil Content is converted into a 4-20mA current signal and a MODBUS-RS485 data frame, and is output simultaneously, and the numerical value and trend chart are displayed on the OLED screen.

[0027] The embodiments of the application are described above, but the application is not limited to the above specific embodiments, the above specific embodiments are only illustrative, not restrictive, and those skilled in the art can make many forms under the inspiration of the application, which all belong to the protection of the application.

Claims

1. An oil-water detector based on the principle of liquid quality resonance measurement, characterized in that, include: The parameter sensing unit is used to contact the oil-water mixture in the pipeline. It includes a fluid carrier with a measuring chamber, a measuring probe disposed in the measuring chamber, and a resonator built into the measuring probe. A data processing unit, signal-connected to the parameter sensing unit, includes: The signal transmitting module is used to transmit an acoustic frequency sweep signal to the resonator to excite the liquid column resonance, and at the same time transmit electromagnetic short waves of a predetermined frequency to the oil-water mixture. The signal acquisition module is used to acquire the resonant frequency signal of the resonator and the absorption and attenuation signal of electromagnetic shortwave. The data processing module is used to calculate the density parameter of the medium based on the resonant frequency signal, calculate the dielectric constant parameter of the medium based on the absorption attenuation signal, identify the phase state of the medium based on the density parameter and dielectric constant parameter, select the corresponding calculation model based on the identification result, and output the oil content value in the water.

2. The oil-water detector based on the principle of liquid quality resonance measurement according to claim 1, characterized in that, The specific logic for the data processing module to identify the phase state of the medium includes: calculating the ratio of the change in dielectric constant parameter to density parameter per unit time; when the ratio is greater than a preset threshold, the medium is determined to be in an oil-in-water phase; otherwise, it is determined to be in a water-in-oil phase.

3. The oil-water detector based on the principle of liquid quality resonance measurement according to claim 2, characterized in that, The data processing module pre-stores a first calculation sub-model and a second calculation sub-model corresponding to the oil-in-water phase and the water-in-oil phase, respectively. When the phase is identified as an oil-in-water phase, the first calculation sub-model is called and the fitting calculation is mainly based on the dielectric constant parameter. When the phase is identified as a water-in-oil phase, the second calculation sub-model is called and the fitting calculation is mainly based on the density parameter.

4. The oil-water detector based on the principle of liquid quality resonance measurement according to claim 1, characterized in that, The data processing unit also includes a wireless communication module for wirelessly connecting with an external handheld debugging terminal to receive adjustment instructions for the translation coefficients and / or elevation coefficients in the calculation model.

5. The oil-water detector based on the principle of liquid quality resonance measurement according to claim 1, characterized in that, The outer surface of the measuring probe is coated with a nano-Teflon anti-adhesion coating, and it is electrically connected to the data processing unit through an automatic latching structure.

6. The oil-water detector based on the principle of liquid quality resonance measurement according to claim 1, characterized in that, The parameter sensing unit and the data processing unit are integrated within the same explosion-proof housing, forming an integrated structure.

7. The oil-water detector based on the principle of liquid quality resonance measurement according to claim 6, characterized in that, The explosion-proof housing is equipped with a sealed connector for detachably connecting the parameter sensing unit and the measuring pipe.

8. An oil-water detector based on the liquid-mass resonance measurement principle according to claim 7, characterized in that, The data processing unit also includes a display module for displaying the oil content value and / or change curve in water in real time.

9. An oil-water detector based on the liquid-mass resonance measurement principle according to claim 1, characterized in that, The predetermined frequency of the electromagnetic shortwave emitted by the signal transmitting module is 4MHz.

10. An oil-water detection method, using an oil-water detector based on the liquid-mass resonance measurement principle as described in any one of claims 1-9, characterized in that, The following steps are included: S100: Allows the oil-water mixture to be measured to flow through the measurement chamber of the parameter sensing unit; S200: Simultaneously transmits an audio frequency sweep signal and a predetermined frequency electromagnetic shortwave through a signal transmission module; S300: Synchronously acquires resonant frequency signal and absorption attenuation signal through signal acquisition module; S400: Through the data processing module, it executes phase identification and oil content calculation logic to output the oil content value in the water.

Images