A rapid detection device for water content in oil and its calibration method

Abstract

The present invention aims to propose a rapid detection device for water content in oil and a calibration method thereof. The device utilizes a microwave method to rapidly detect the water content in oil, which is characterized by high speed. The microwave method is then self-calibrated using a high-precision spectroscopy method, so that after the water in the measured liquid is fully evaporated, the water content can be measured with high precision through the spectral absorption effect of the gas. The two methods are combined, and the microwave test results are calibrated using the test results of the infrared spectroscopy method, and a correction coefficient is formed for the rapidly measured microwave method results, thereby leveraging the advantage of the microwave method's fast response to form a rapid detection method.

Description

Technical Field

[0001] The present invention relates specifically to the field of petrochemical industry, and in particular to a device for quickly detecting the water content in oil and a calibration method thereof. Background Art

[0002] With the development of the times and social progress, people's use of and attention to oil is increasing. Research has found that factors affecting the performance and stability of oil supply systems include contamination such as microscopic water particles. Oil is widely used in various fields in daily life, such as the automotive, power, chemical, and food industries. Therefore, scientific and reasonable measurement of the water content of common oil types is crucial. Therefore, rapid self-calibration testing of minute water content in oil is a key focus.

[0003] Among existing technologies for detecting water content in oil, one commonly used method is to evaporate the water inside the crude oil for measurement. However, this technical method has the disadvantages of poor detection accuracy and inconvenient operation. Another commonly used method is the microwave method, which is heavily dependent on the measurement accuracy and stability of electronic power facilities and equipment. Therefore, the present invention application intends to reasonably combine the two to improve the accuracy and stability of the oil water content detection device.

[0004] The advantages of microwave moisture measurement include fast measurement speed, high accuracy, non-invasiveness, and unaffected by the color and transparency of the measured medium. However, its disadvantages include susceptibility to interference from the surrounding environment and the need for shielding and anti-interference measures. Infrared spectroscopy offers high measurement accuracy, but requires heating the oil to convert it into gas, leading to longer waiting times for test results.

[0005] Prior art related to the present invention, and references based on the calculation formula in the present invention:

[0006] Document 1: JOHA NSSON J, HAGMANA O, OJA J. Predicting moisture and density of Scots pine by microwave SCanning of sawn timber, Computers and Electronics in Agriculture, 2003, 41.

[0007] Document 2: ROBISON DA, GARDNER CMK, Cooper J D. Measurement of relative permittivity in sandy soils using TDR, capacity and theta probes: comparison, including the effects of bulk soil electrical conductivity, Journal of Hydrology, 1999, 223.

[0008] Reference 3: Zhang Yongpan. Research on experimental device for online measurement of water content in crude oil by microwave projection method [D]. Master's thesis of Daqing Petroleum Institute, 2009.

[0009] The values ​​of constants related to the present invention are based on the following documents:

[0010] Reference 4: An Li. Research on polarization and dielectric properties of water molecules [D]. Hebei University of Technology, 2005.

[0011] Reference 5: Li Ke. Research on oil quality monitoring system based on dielectric constant [D]. Yanshan University, 2017. Summary of the Invention

[0012] The present invention aims to solve the problem of accuracy when using microwaves alone to detect the water content in oil, and to solve the problem that when using infrared spectroscopy alone to detect the water content in oil, it takes a long time to detect the water content due to the need to heat the gas in the gas chamber.

[0013] In order to solve the above problems, this application is implemented through the following technical solutions:

[0014] A device for quickly detecting water content in oil comprises an oil pipeline, one end of which is provided with a suction port, the suction port being fixedly connected to a microwave sensor, the microwave sensor being connected to a data acquisition unit via a data cable, the data acquisition unit being connected to an electronic control module via a data cable, and the electronic control module being further connected to an infrared emitter via a data cable.

[0015] The other end of the oil pipeline is connected to the inlet of the metering pump, the output end of the metering pump is connected to the inlet of the heating furnace, the output end of the heating furnace is connected to the inlet of the fine filter, the output end of the fine filter is connected to one end of the air pump, the air outlet of the air pump is connected to the air chamber, and the air outlet of the air chamber is connected to the exhaust gas collector.

[0016] The data acquisition unit is connected to the calibration analyzer via a data line, and the calibration analyzer is connected to the receiver via a data line.

[0017] The air chamber is arranged between the infrared transmitter and the receiver.

[0018] A moisture content tester is provided at the bottom of the microwave sensor, and a microwave generator is installed inside the moisture content tester. The output end of the microwave generator is connected to the power divider through a data line, the power divider is connected to the microwave transmitting probe through a data line, the power divider is connected to the detector through a data line, and one end of the detector is connected to the microwave receiving probe through a data line. The microwave transmitting probe and the microwave receiving probe are installed in the oil pipeline.

[0019] The side wall of the air chamber is made of infrared optically transparent material, and the photosensitive sheet in the material is pyroelectric material.

[0020] The calibration method of the oil water content rapid detection device comprises the following steps:

[0021] S1, turn on the electronic control module 4, and inject oil with different water contents into the oil pipeline 1 in batches;

[0022] S1.1, the water content tester 201 measures the mass water content η through the attenuation value A and phase P of different oils w , transmitted back to the data acquisition unit 3 through the microwave sensor 2;

[0023] S1.2, the receiver 6 transmits the infrared signals of the oil with different water contents to the calibration analyzer 5; the calibration analyzer 5 converts the infrared signals into mass water content y by infrared method and transmits them to the data acquisition unit 3;

[0024] S2, the collection unit 3 collects the moisture content η in step S1.1 w Fitting the mass moisture content y in step S1.2 to obtain the relationship between y and η w The linear first-order calibration equation of .

[0025] In the step S1.1, the mass moisture content η w The calculation formula is:

[0026] .

[0027] The η w The expressions of attenuation A and phase shift P in the expression are:

[0028] ;

[0029] ;

[0030] In the expressions of attenuation A and phase shift P, λ0 is the wavelength of the incident wave; D is the inner diameter of the pipe, D=L W + L O +L g ;L Wis the thickness of the aqueous phase, L O is the thickness of the oil phase, L g is the thickness of the gas phase; ε′ is the energy storage factor, ε″ is the loss factor; π is the circumference of the circle;

[0031] Ignoring the mass of gas in the oil, the expression of ε′ is:

[0032] ;

[0033] The expression of ε″ is:

[0034] ;

[0035] ρ is the density of the mixed oil, ρ w is the density of pure water, ρ o is the density of pure oil; ε′ w is the energy storage factor of pure water, ε″ w is the loss factor of pure water, ε′ o is the energy storage factor of pure oil, ε″ o is the loss factor of pure water,

[0036] in, ; ;

[0037] V is the total volume of oil, V g 、V W 、V O is the volume of air, pure water and pure oil in the mixture.

[0038] In step S2, the infrared method calibrates the moisture content y and the microwave method tests the moisture content result η w The fitting relationship is: y=1.007η w +1.0172.

[0039] Compared with the prior art, the present invention has the following beneficial effects:

[0040] 1. This invention is used to quickly detect the water content in oil. It uses microwave radiation to measure the water content for a preliminary determination. First, a microwave signal is transmitted into the measured medium through a transmitting probe, and then the reflected microwave signal is received by a receiving probe. Due to the different dielectric constants and electrical conductivity of the measured medium, the intensity and phase of the reflected microwave signal will vary. By measuring these changes, the water content of the measured medium can be calculated.

[0041] 2. The present invention quantitatively calibrates the moisture content. A quantitative pump is used to extract a certain amount of oil-containing liquid and a spectroscopic method is used to obtain high-precision water content data. The microwave method is self-calibrated to fully evaporate the moisture therein.

[0042] 3. The present invention combines the two methods, calibrating the microwave method by spectroscopy to form a correction coefficient, and then taking advantage of the fast response of the microwave method to form a method for rapid detection of water content; it is used for detecting oils with a water content of ≤1%.

[0043] 4. The present invention is used for rapid self-calibration of minute water content in oil. The detection method and device are simple and have a wide range of applications. It can be widely used in the maintenance and calibration of petrochemical and large-scale lubricating water content equipment.

[0044] 5. The present invention aims to propose a device for quickly detecting the water content in oil and a calibration method thereof. First, the microwave method is used to quickly detect the water content in the oil, and the output value is a current value, which is characterized by high speed; second, the spectral method with high water content measurement accuracy is used to calibrate the water content measured by the microwave method, so that the water therein is fully evaporated; third, the two methods are combined, and the microwave method is calibrated by the spectral method to form a correction coefficient, and then the advantage of the fast response of the microwave method is utilized. Under the same conditions, the water content detected by the microwave method and the water content detected by the infrared method are fitted to obtain a correction relationship applicable to the entire water content range from 0 to 0.01 for both. After the microwave method is used to quickly measure the water content, the correction relationship is brought into play to correct the water content. Finally, an accurate value equivalent to the water content measured by infrared spectroscopy under the same conditions is obtained; thus, a device and a detection method for quickly and accurately detecting the water content in oil are formed.

[0045] 6. The fitting relationship obtained by this calibration method, combined with the microwave water measuring device in the present invention, saves the infrared preheating and insulation time, and quickly and accurately obtains the test results of the water content in the oil. Compared with the direct infrared measurement, the measurement time is shortened from more than 30 minutes to less than 2 minutes, which is shorter. Compared with the direct microwave method for measuring the water content, the accuracy is higher and the service life of the quantitative pump in the infrared water measuring instrument is increased. When the probe of the water content tester is immersed in oil for a long time, the accuracy will decrease, resulting in the need to regularly check and calibrate the transmitting probe and the receiving probe. The method in the present invention can solve the probe accuracy problem of the water content tester by recalibrating the fitting relationship. BRIEF DESCRIPTION OF THE DRAWINGS

[0046] Figure 1 This is a schematic diagram of the principle of a rapid detection device for water content in oil;

[0047] Figure 2 This is a schematic diagram of microwave projection into the oil-gas-water mixed layer;

[0048] Figure 3 This is a flow chart of microwave moisture content measurement;

[0049] Figure 4 It is a structural diagram of a rapid detection device for water content in oil;

[0050] Figure 5 This is an enlarged schematic diagram of the oil water content rapid detection device A;

[0051] Figure 6 The moisture content y calibrated by infrared method and the moisture content η tested by microwave method w The fitting relationship diagram of

[0052] Figure numerals: oil pipeline 1, suction port 101, microwave sensor 2, tester 201, microwave generator 2011, detector 2013, power splitter 2012, transmitting probe 202, receiving probe 203; data acquisition unit 3, electronic control module 4, calibration analyzer 5, receiver 6, metering pump 7, heating furnace 8, fine filter 9, air pump 10, air chamber 11, exhaust gas collector 12, infrared transmitter 13. DETAILED DESCRIPTION

[0053] The microwave sensor 2, data acquisition unit 3, electronic control module 4, calibration analyzer 5, receiver 6, dosing pump 7, heating furnace 8, air pump 10, and infrared emitter 13 in the present invention are all powered by an external power supply. The electronic control module 4 controls the power switches of the data acquisition unit 3, calibration analyzer 5, receiver 6, dosing pump 7, heating furnace 8, air pump 10, and infrared emitter 13 via data cables. Electronic components connected by data cables can also be connected wirelessly. The infrared emitter 13 emits infrared light. The model of microwave sensor 2 is preferably Guangyan Detection GTIO-1501; the model of microwave generator 2011 is preferably Beijing Dahua solid-state microwave signal source, model DH1121C; the model of power divider 2012 is preferably Antma rectangular waveguide BJ-100; the model of detector 2013 is preferably Guangyan detection diode 2DV27; the model of data acquisition unit 3 is preferably VK10X charge amplifier; the model of electronic control module 4 is the self-developed electronic control equipment based on STM32; the calibration analyzer 5 is preferably based on the host computer programming and industrial computer written in C++, and the model of receiver 6 is preferably infrared receiver DIP-3; the pyroelectric material is preferably lithium tantalate material with high thermoelectric coefficient, which is made into a detection element with a size of 2×1mm.

[0054] The device diagram illustrates the connection relationship of the device, please refer to Figure 4 and Figure 5A rapid detection device for the water content in oil comprises an oil pipeline 1. One end of the oil pipeline 1 is provided with a suction port 101, which is fixedly connected to a microwave sensor 2. The microwave sensor 2 is connected to a data acquisition unit 3 via a data cable. The data acquisition unit 3 is connected to an electronic control module 4 via a data cable. The electronic control module 4 is also connected to an infrared transmitter 13 via a data cable. The other end of the oil pipeline 1 is connected to the inlet of a metering pump 7. The output end of the metering pump 7 is connected to the inlet of a heating furnace 8. The output end of the heating furnace 8 is connected to the inlet of a fine filter 9. The output end of the fine filter 9 is connected to one end of an air pump 10. The air outlet of the air pump 10 is connected to an air chamber 11. The air outlet of the air chamber 11 is connected to an exhaust gas collector 12. The data acquisition unit 3 is connected to a calibration analyzer 5 via a data cable, and the calibration analyzer 5 is connected to a receiver 6 via a data cable. The air chamber 11 is disposed between the infrared transmitter 13 and the receiver 6.

[0055] Microwave sensor 2 has a moisture content meter 201 installed at its base. A microwave generator 2011 is housed within this meter. The output of microwave generator 2011 is connected via a data cable to a power divider 2012, which in turn is connected via a data cable to a microwave transmitter probe 202. This is connected via a data cable to a detector 2013, which in turn is connected via a data cable to a microwave receiver probe 203. Microwave transmitter probe 202 and microwave receiver probe 203 are installed within oil pipeline 1. The sidewalls of gas chamber 11 are made of infrared optically transparent material, and the photosensitive film within the material is pyroelectric. The inner diameter D of the pipeline is the inner diameter of the suction port 101.

[0056] Example 1

[0057] The connection diagram of each component of the oil water content rapid detection device is as follows Figure 4 and Figure 5 shown.

[0058] Principle of Microwave Method for Measuring Water Content in Oil: This device uses the microwave projection method to detect the water content in oil. Microwaves passing through water-containing media will cause microwave signal attenuation and phase shift. When actually measuring the water content of a medium, because the dielectric constant of highly polarized water molecules differs significantly from that of other substances, even a slight change in the water content of the medium will cause a significant change in the attenuation and phase of the microwave signal. Therefore, when microwaves pass through the medium to be measured, the change in dielectric constant will cause changes in the microwave signal's attenuation value A and phase shift P, and the degree of change is related to the water content in the medium. Figures 1 to 3 .

[0059] After microwaves pass through a medium, their power attenuates. The magnitude of the attenuation and phase shift also depends on the non-electrical quantities D and ε*. The microwave method for measuring water content is based on the significant difference in the dielectric constants of oil and water. Oil-water mixtures with varying water contents have different dielectric constants and, therefore, different absorption of microwave signals. The water content of the mixture can be determined by the magnitude of the microwave signal after passing through it. Generally, the relative complex dielectric constant of a medium can be expressed as a complex number:

[0060] =ε′ - jε″ (1-1)

[0061] Where: is the relative complex dielectric constant of oil; ε′ is the energy storage factor, which indicates the energy storage capacity; ε″ is the loss factor, which indicates the dielectric loss; j is the symbol of the imaginary part.

[0062] The water content of an oil-water mixture can also be determined by the relative dielectric constant of the oil-water mixture. At room temperature and pressure, the relative dielectric constant of water is as high as 78.36, while that of oil is 2.3, a significant difference. Water-in-oil mixtures are complex structures. Oil is insoluble in water. During flow or agitation, the two collide and interpenetrate, mixing in the form of particles (of varying diameters). There are two possible mixing states. When the volume of the oil phase exceeds that of the water phase, the oil phase becomes the continuous phase and the water phase becomes the dispersed phase. Water is dispersed in the oil phase in the form of particles, often referred to as water-in-oil.

[0063] For the convenience of calculation, the mass percentage of water in the three-phase oil mixture of oil, water and gas is defined as η w , and its calculation formula is:

[0064] (1-2)

[0065] Where η w is the water content of the oil-liquid mixture; m w 、m o 、m g are the masses of water, oil, and gas in the oil-liquid mixture, respectively. Since the mass of oil and water in the mixture is much greater than the mass of gas, the mass of gas in the oil is ignored. g , so formula (1-2) can be approximated as:

[0066] (1-3)

[0067] Where m=m w + m o ;m=ρ×V;m w =ρ w ×V w ;m o =ρ o ×V o ;mw =m×η w

[0068] according to =ε′ - jε″; we can get =ε′ w -jε″ w ; =ε′ o -jε″ o ;

[0069] The expressions of the attenuation value A and phase shift P of the microwave signal passing through the oil-water-gas three-phase mixed fluid are:

[0070] P=L W ×P w + L O ×P o + L g ×P g (1-4)

[0071] A=L W ×A W +L O ×A O + Lg×Ag(1-5)

[0072] D=L W + L O +L g (1-6)

[0073] Where: L w 、L o 、L g is the thickness of water phase, oil phase and gas phase; P w 、P o 、P g A is the phase shift of the microwave signal when it passes through the unit thickness of the water phase, oil phase, and gas phase; w 、A o 、A g is the attenuation of microwave signal when passing through unit thickness of water phase, oil phase and gas phase; D is the inner diameter of the pipe.

[0074] According to the relevant principles and approximate conditions of electromagnetic waves incident on lossy media, formulas (1-4) and (1-5) are calculated using the calculation methods disclosed in References 1 and 2 to obtain the following formula:

[0075] (1-7)

[0076] (1-8)

[0077] Where π is the circumference of a circle and λ0 is the wavelength of the incident wave.

[0078] Since the actual oil can be regarded as a three-phase mixed fluid of oil, gas and water, it can be approximated as a mixture of air, pure water and pure oil in the oil mixture. is 1, the complex dielectric constant can be expressed as:

[0079] (1-9)

[0080] (1-10)

[0081] Where: V g 、V w 、V o is the volume of air, pure water and pure oil in the mixture; ρ is the density of the oil mixture, ρ w is the density of pure water, ρ o is the density of pure oil. is the relative dielectric constant of oil, is the dielectric constant of pure water, is the dielectric constant of pure oil.

[0082] In formula (1-9) and formula (1-10), Expanding into the form of energy storage factor ε′ and loss factor ε″, we can obtain:

[0083] (1-11)

[0084] (1-12)

[0085] Since V g =VV w -V o ,then:

[0086] (1-13)

[0087] Substituting formula (1-13) into formula (1-11) yields:

[0088] (1-14)

[0089] Dividing formula (1-14) by formula (1-12) yields:

[0090] (1-15)

[0091] After sorting, the water content of crude oil η w and the mixture density ρ are:

[0092] (1-16)

[0093] (1-17)

[0094] The water content η in the oil-liquid mixture is obtained from equations (1-7), (1-8), (1-16), and (1-17): w The relationship between the attenuation value A and the phase shift P is:

[0095] (1-18)

[0096] In summary, different microwave signal attenuation values ​​A and phase P are directly measured by microwave test circuit, and then ε is obtained by consulting references 4 and 5. w ′,ε w ″,ε o ′,ε o ″, substitute λ0 and the inner diameter of the pipe D to calculate the water content η in the mixture using formula (1-18) w .

[0097] Table 1 Data of test samples 1 to 11

[0098]

[0099] like Figure 6 As shown in the figure, 11 oil samples with different water contents were injected into the oil pipeline in batches for measurement. W =1000 kg / m 3 , ρ O = 830 kg / m 3 , the inner diameter of the pipe D = 20mm = 0.02m, the incident wavelength of the microwave λ0 = 0.0319 m, the dielectric constant of pure water = 78.36=ε w ′,ε w =0.00001, dielectric constant of pure oil = 2.3=ε o ′;ε o ″=0.001,ε″=0.001.

[0100] The microwave data for samples 1 through 11 are shown in Table 1. The moisture content was calculated using Equation (1-18). The attenuation values ​​A and phase shift P for samples 1 through 11 in Table 1 were obtained through instrumental testing. For the constants in Table 1, please refer to References 4 and 5.

[0101] The microwave measurement results were fitted by infrared spectroscopy, and the infrared spectroscopy measurement value with high accuracy and slow test speed was used as the calibration value y, and the microwave measurement value with low accuracy and fast test speed was used as η. w, measure 11 test samples with moisture content ranging from 0ppm to 160ppm in turn, and calculate y and η by the least squares method w The functional relationship does not exceed the second order, ensuring the function correlation R ≥ 99%. After correction, the microwave measuring instrument can form a detection capability with high accuracy and fast measurement speed, such as Figure 6 As shown, R 2 =0.9861, R≥99%.

[0102] Infrared spectroscopy method for measuring the water content of oil. Sampling conditions: Using the AGA2000d infrared analyzer provided by Aiyi Technology Co., Ltd., the water content test program in the infrared analyzer is ACP200-R program version 2.0. 1 ml of mixed oil was extracted from each oil sample with different water content using a quantitative pump. The mixture was heated to 100°C in a heating furnace at a heating rate of 5°C / min and kept warm for more than 30 minutes. After filtering, the mixture was transferred into the air chamber via an air pump. The infrared emitter was set to a wavelength of 1450 nm. The η values ​​obtained by microwave method were measured for test samples 1 to 11. w The water content y of the oil was measured by infrared spectroscopy. The data are shown in Table 2:

[0103] Table 2 η measured by microwave method w and infrared spectroscopy to measure the water content of oil

[0104]

[0105] Fitting of the moisture content relationship measured by the two methods: y=1.007η w +1.0172.

[0106] The preferred instrument model of the present invention is the matching power supply and circuit, which only prefers one model, and does not limit the present invention to using this model of instrument or component. For those skilled in the art, other types of water-containing oils with different densities can also be used in combination with infrared calibration, or other component models in the infrared method and microwave method can be converted to obtain other fitting equations. Improvements to these technical solutions all fall within the scope of protection of the present invention.

Claims

1. A device for quickly detecting the water content in oil, comprising an oil pipeline (1), characterized in that: One end of the oil pipeline (1) is provided with a suction port (101), the suction port (101) is fixedly connected to the microwave sensor (2), the microwave sensor (2) is connected to the data acquisition unit (3) via a data line, the data acquisition unit (3) is connected to the electric control module (4) via a data line, and the electric control module (4) is also connected to the infrared emitter (13) via the data line. The other end of the oil pipeline (1) is connected to the inlet of the quantitative pump (7), the output end of the quantitative pump (7) is connected to the inlet of the heating furnace (8), the output end of the heating furnace (8) is connected to the inlet of the fine filter (9), the output end of the fine filter (9) is connected to one end of the air pump (10), the air outlet of the air pump (10) is connected to the air chamber (11), and the air outlet of the air chamber (11) is connected to the exhaust gas collector (12); The data acquisition unit (3) is connected to the calibration analyzer (5) via a data line, and the calibration analyzer (5) is connected to the receiver (6) via a data line; The air chamber (11) is arranged between the infrared transmitter (13) and the receiver (6).

2. The device for rapid detection of water content in oil according to claim 1, characterized in that: A moisture content tester (201) is provided at the bottom of the microwave sensor (2), a microwave generator (211) is installed inside the moisture content tester (201), an output end of the microwave generator (211) is connected to a power splitter (2012) via a data line, the power splitter (2012) is connected to a microwave transmitting probe (202) via a data line, the power splitter (2012) is connected to a detector (2013) via a data line, one end of the detector (2013) is connected to a microwave receiving probe (203) via a data line, and the microwave transmitting probe (202) and the microwave receiving probe (203) are installed in the oil pipeline (1).

3. The oil water content rapid detection device according to claim 1, characterized in that: The side wall of the air chamber (11) is made of infrared optically transparent material, and the photosensitive sheet in the material is a pyroelectric material.

4. A calibration method for a rapid detection device for water content in oil according to any one of claims 1 to 3, characterized in that: The following steps are involved: S1. Turn on the electronic control module and inject oil with different water contents into the oil pipeline in batches; S1.

1. The moisture content tester at the bottom of the microwave sensor measures the mass moisture content η through the attenuation value A and phase P of different oils. w , transmitted back to the data acquisition unit through the microwave sensor; S1.

2. The receiver transmits infrared signals of oils with different water contents to the calibration analyzer. The calibration analyzer converts the infrared signals into mass water content y using an infrared method and transmits the converted signals to the data acquisition unit. S2, the collection unit collects the moisture content η in step S1.1 w Fitting the mass moisture content y in step S1.2 to obtain the relationship between y and η w The linear first-order calibration equation of .

5. The calibration method according to claim 4, characterized in that: In the step S1.1, the mass moisture content η w The calculation formula is: ； The η w The expressions of attenuation A and phase shift P in the expression are: ； ； In the expressions of attenuation A and phase shift P, λ0 is the wavelength of the incident wave; D is the inner diameter of the pipe, D=L W + L O +L g ;L W is the thickness of the aqueous phase, L O is the oil phase thickness, Lg is the gas phase thickness; ε′ is the energy storage factor, ε″ is the loss factor; π is the circumference of the circle; Ignoring the mass of gas in the oil, the expression of ε′ is: ； The expression of ε″ is: ； ρ is the density of the mixed oil, ρ w is the density of pure water, ρ o is the density of pure oil; ε′ w is the energy storage factor of pure water, ε″ w is the loss factor of pure water, ε′ o is the energy storage factor of pure oil, ε″ o is the loss factor of pure water, in, ; ; V is the total volume of oil, V g is the volume of air in the mixture.

6. The calibration method according to claim 4, characterized in that: In step S2, the infrared method calibrates the moisture content y and the microwave method tests the moisture content result η w The fitting relationship is: y=1.007η w +1.0172.

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