Rapid detection device for water content of oil and calibration method thereof

Abstract

According to the rapid detection device for the water content of the oil and the calibration method thereof, the water content of the oil is rapidly detected through a microwave method, and the characteristic speed is high; self-calibration is carried out on the microwave method by utilizing a high-precision spectrum method, so that the water content can be measured at high precision through the spectrum absorption effect of gas after the water of the measured liquid is fully evaporated; the two methods are combined, a microwave method test result is calibrated according to an infrared spectroscopy test result, a formation correction coefficient of the microwave method result capable of being rapidly measured is formed, and the rapid detection method is formed by giving play to the advantage of rapid response of the microwave method.

Description

Technical Field

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

[0002] With the development of the times and social progress, people's use and attention to oil are increasing. In the process of research, it was found that the factors affecting the performance and stability of the oil supply system include pollution such as micro-water particles. In daily life, oil is widely used in various fields, such as the automotive industry, power industry, chemical industry, and food industry, etc., so it is very important to scientifically and reasonably determine the water content of common types of oil. Therefore, the rapid self-calibration detection process of micro-water content in oil must be focused on.

[0003] Among the existing technologies for detecting water content in oil, a commonly used method is to evaporate the water inside the crude oil for measurement, but 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 method for measuring moisture are fast measurement speed, high accuracy, non-invasiveness, and no influence from the color and transparency of the measured medium. The disadvantage is that it is easily interfered by the surrounding environment and requires necessary shielding and anti-interference treatment. The advantage of infrared spectroscopy is high measurement accuracy, but since it is necessary to heat the oil to convert it into gas, the waiting time for the test results is long.

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

[0006] 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.

[0007] 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.

[0008] The constant values ​​related to the present invention are based on the following documents: Reference 4: An Li. Research on polarization and dielectric properties of water molecules [D]. Hebei University of Technology, 2005.

[0009] Reference 5: Li Ke. Research on oil quality monitoring system based on dielectric constant [D]. Yanshan University, 2017. Summary of the invention

[0010] The present invention aims to solve the problem of accuracy when only microwaves are used to detect the water content in oil, and to solve the problem that when only infrared spectroscopy is used to detect the water content in oil, it takes a long time to detect the water content because the gas in the gas chamber needs to be heated.

[0011] In order to solve the above problems, the present application is implemented through the following technical solutions: A rapid detection device for water content in oil comprises an oil pipeline, one end of which is provided with a suction port, the suction port is fixedly connected to a microwave sensor, the microwave sensor is connected to a data acquisition unit via a data line, the data acquisition unit is connected to an electric control module via a data line, and the electric control module is also connected to an infrared transmitter via the data line. The other end of the oil pipeline is connected to the sampling port 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.

[0012] 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.

[0013] The air chamber is arranged between the infrared transmitter and the receiver.

[0014] 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 a power divider through a data line, the power divider is connected to a microwave transmitting probe through a data line, the power divider is connected to a detector through a data line, and one end of the detector is connected to a microwave receiving probe through a data line. The microwave transmitting probe and the microwave receiving probe are installed in the oil pipeline.

[0015] The side wall of the air chamber is made of infrared optical transparent material, and the photosensitive sheet in the material is pyroelectric material.

[0016] The calibration method of the oil water content rapid detection device comprises the following steps: S1, turning on the electronic control module 4, and injecting oils with different water contents into the oil pipeline 1 in batches; S1.1, 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; S1.2, the receiver 6 transmits the infrared signals of the oil with different water contents to the calibration analyzer 5 respectively; the calibration analyzer 5 converts the infrared signals into the mass water content y by infrared method and transmits them to the data acquisition unit 3; S2, the collection unit 3 collects the moisture content η in step S1.1 w And the mass moisture content y in step S1.2 is fitted to obtain y and η w The linear first-order calibration equation of .

[0017] In step S1.1, the mass moisture content η w The calculation formula is: .

[0018] 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 water 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 a 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 、V W 、V O is the volume of air, pure water and pure oil in the mixture.

[0019] 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.

[0020] Compared with the prior art, the present invention has the following beneficial effects: 1. The present invention is used to quickly detect the water content in oil, and makes a preliminary judgment by measuring the water content using microwave radiation; first, the microwave signal is transmitted to the measured medium through the transmitting probe, and then the reflected microwave signal is received by the receiving probe. Since the dielectric constant and conductivity of the measured medium are different, the intensity and phase of the reflected microwave signal will change. By measuring these changes, the water content of the measured medium can be calculated.

[0021] 2. The present invention quantitatively calibrates the water content, extracts a certain amount of oil-containing liquid through a quantitative pump, obtains high-precision water content data using spectroscopy, and performs self-calibration on the microwave method to fully evaporate the water therein.

[0022] 3. The present invention combines the two methods, calibrates the microwave method by spectroscopy to form a correction coefficient, and then takes advantage of the fast response of the microwave method to form a method for quickly detecting water content; it is used for detecting oil with a water content of ≤1%.

[0023] 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.

[0024] 5. The present invention aims to propose a rapid detection device for water content in oil and a calibration method thereof. First, the water content in oil is rapidly detected by microwave method, and the output value is a current value, which is characterized by high speed. Second, the water content measured by microwave method is calibrated by spectroscopy with high water content measurement accuracy, so that the water therein is fully evaporated. Third, the two methods are combined, and the microwave method is calibrated by spectroscopy to form a correction coefficient, and then the advantage of fast response of microwave method is brought into play. Under the same conditions, the water content detected by microwave method and the water content detected by infrared method are fitted to obtain a correction relationship applicable to the water content of both methods in the entire range of 0~0.01. After the water content is rapidly measured by microwave method, 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 rapidly and accurately detecting water content in oil are formed.

[0025] 6. The fitting relationship obtained by the 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 to measure the water content, the accuracy is higher and the service life of the quantitative pump in the infrared water measuring instrument can be 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

[0026] Figure 1 This is a schematic diagram of the principle of a rapid detection device for water content in oil; Figure 2 This is a schematic diagram of microwave projection of oil, gas and water mixed layer; Figure 3 It is the flow chart of microwave moisture content measurement; Figure 4 It is a structural schematic diagram of a rapid detection device for water content in oil; Figure 5 This is an enlarged schematic diagram of the oil water content rapid detection device A; Figure 6 The infrared method calibrated moisture content y and the microwave method tested moisture content result η w The fitting relationship diagram of Figure numerals: oil pipeline 1, suction port 101, microwave sensor 2, tester 201, microwave generator 2011, detector 2013, power divider 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

[0027] The microwave sensor 2, data acquisition unit 3, electric control module 4, calibration analyzer 5, receiver 6, quantitative pump 7, heating furnace 8, air pump 10, and infrared transmitter 13 in the present invention are all powered by an external power supply; the electric control module 4 controls the power switch connecting the data acquisition unit 3, calibration analyzer 5, receiver 6, quantitative pump 7, heating furnace 8, air pump 10 and infrared transmitter 13 through a data line. Electronic components connected by data line control can also be connected wirelessly. The infrared transmitter 13 emits an infrared light source. 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 a detection element with a size of 2×1mm made of lithium tantalate material with a high thermoelectric coefficient.

[0028] The device diagram illustrates the connection relationship of the device. Figure 4 and Figure 5 A rapid detection device for water content in oil includes an oil pipeline 1, a suction port 101 is provided at one end of the oil pipeline 1, the suction port 101 is fixedly connected to a microwave sensor 2, the microwave sensor 2 is connected to a data acquisition unit 3 through a data line, the data acquisition unit 3 is connected to an electronic control module 4 through a data line, the electronic control module 4 is also connected to an infrared transmitter 13 through a data line, the other end of the oil pipeline 1 is connected to an inlet of a quantitative pump 7, the output end of the quantitative pump 7 is connected to an inlet of a heating furnace 8, the output end of the heating furnace 8 is connected to an 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, and 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 through a data line, and the calibration analyzer 5 is connected to a receiver 6 through a data line. The air chamber 11 is arranged between the infrared transmitter 13 and the receiver 6.

[0029] A moisture content tester 201 is provided at the bottom of the microwave sensor 2. A microwave generator 2011 is installed inside the moisture content tester 201. The output end of the microwave generator 2011 is connected to a power divider 2012 via a data line. The power divider 2012 is connected to a microwave transmitting probe 202 via a data line. The power divider 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. The microwave transmitting probe 202 and the microwave receiving probe 203 are installed in the oil pipeline 1. The side wall of the gas chamber 11 is made of infrared optical transparent material, and the photosensitive sheet in the material is a pyroelectric material. The inner diameter D of the pipeline is the inner diameter of the pipeline of the suction port 101.

[0030] Example 1 The schematic diagram of the connection relationship of the various components of the oil water content rapid detection device is as follows Figure 4 and Figure 5 shown.

[0031] Principle of measuring the water content of oil by microwave method: This device uses microwave projection method to detect the water content in oil. Since microwaves pass through water-containing media, they will cause attenuation of microwave signals and changes in phase. When actually measuring the water content of the medium, because the dielectric constant of highly polarized water molecules is significantly different from that of other substances, a slight change in the water content in the medium will cause a large change in the attenuation and phase of the microwave signal. Therefore, when microwaves pass through the medium to be measured, the change in the dielectric constant will cause changes in the attenuation value A and phase shift P of the microwave signal, and the degree of change is related to the water content in the medium. Please refer to Figure 1~Figure 3 .

[0032] After microwaves pass through a medium, their power will attenuate. The magnitude of the attenuation and phase shift is also related to the non-electrical quantity D and ε*. The basis for measuring water content by microwave method is that the dielectric constants of oil and water are quite different. Oil-water mixtures with different water contents have different dielectric constants, and thus absorb microwave signals differently. The water content of the oil-water mixture can be measured based on the size of the microwave signal after passing through the oil-water mixture. Usually, the relative complex dielectric constant of a medium can be expressed in complex form: =ε′ - jε″ (1-1) Where: is the relative complex dielectric constant of oil; ε′ is the energy storage factor, indicating the energy storage capacity; ε″ is the loss factor, indicating the dielectric loss; j is the symbol of the imaginary part.

[0033] The water content in the 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, which is a big difference. Water-containing oil is a mixture with a complex structure. Oil is insoluble in water. When flowing or stirring, the two collide and penetrate each other, and mix in the form of particles (with different diameters). There are two kinds of mixed states. When the volume of the oil phase is greater than that of the water phase, the oil phase is the continuous phase and the water phase is the dispersed phase. Water is dispersed in the oil phase in the form of particles, which is often called oil-in-water.

[0034] For the convenience of calculation, the mass percentage of water in the three-phase oil-liquid mixture of oil, water and gas is defined as η w , and its calculation formula is: (1-2) 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 masses of oil and water in the mixture are 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: (1-3) Where m=m w + m o ;m=ρ×V;m w =ρ w ×V w ;m o =ρ o ×V o ;m w =m×η w according to =ε′ - jε″; we can get =ε′ w -jε″ w ; =ε′ o -jε″ o ; The expressions of the attenuation value A and phase shift P of microwave signals passing through the oil-water-gas three-phase mixed fluid are: P=L W ×P w + L O ×P o + L g ×P g (1-4) A=L W ×A W +LO ×A O + Lg×Ag(1-5) D=L W + L O +L g (1-6) 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 microwave signal when it passes through unit thickness of 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.

[0035] 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: (1-7) (1-8) Where π is the circumference of a circle and λ0 is the wavelength of the incident wave.

[0036] 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: (1-9) (1-10) 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.

[0037] Substitute the formula (1-9) and formula (1-10) Expanding into the form of energy storage factor ε′ and loss factor ε″, we can obtain: (1-11) (1-12) Since V g =VV w -V o ,then: (1-13) Substituting formula (1-13) into formula (1-11) yields: (1-14) Dividing formula (1-14) by formula (1-12) yields: (1-15) After sorting, the water content of crude oil η w and the mixture density ρ are: (1-16) (1-17) The water content η in the oil-liquid mixture is obtained by equations (1-7), (1-8), (1-16), and (1-17): w The relationship between the attenuation value A and the phase shift P is: (1-18) 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, and the water content η in the mixture can be calculated by formula (1-18): w .

[0038] Table 1 Data of test samples 1 to 11

[0039] 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 = εo ′;ε o ″=0.001,ε″=0.001.

[0040] The data of test samples 1 to 11 of the microwave method are shown in Table 1, and the moisture content is calculated by formula (1-18). The attenuation value A and phase shift P of test samples 1 to 11 in Table 1 are obtained by instrument testing. For the constants in Table 1, please refer to references 4 and 5.

[0041] 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 , 11 test samples with moisture contents ranging from 0ppm to 160ppm were measured in turn, and y and η were obtained by the least squares method. w The function relationship does not exceed the second order, ensuring the function correlation R ≥ 99%. After correction, the microwave measurement 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%.

[0042] Infrared spectroscopy method for measuring the water content of oil. Sample injection conditions: Use the AGA2000d infrared analyzer provided by AIYI Technology Co., Ltd. The water content test program in the infrared analyzer is the ACP200-R program 2.0 version. Use a quantitative pump to extract 1 ml of mixed oil from oil samples with different water content, heat it to 100°C in a heating furnace at a heating rate of 5°C / min, keep it warm for more than 30 minutes, filter it, and transfer it into the air chamber through an air pump. The infrared transmitter is set to a wavelength of 1450 nm. Use the microwave method to measure the η obtained by 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: Table 2 η measured by microwave method w and infrared spectroscopy to measure the water content of oil

[0043] Fitting of moisture content measured by two methods: y=1.007η w +1.0172.

[0044] The preferred instrument model of the present invention is the matching power supply and circuit, and only one of the models is preferred, rather than limiting the present invention to use this model of instrument or component. For those skilled in the art, other different types of water-containing oils with different densities can also be used in combination with infrared for calibration, or other component models in the infrared method and microwave method can be transformed to obtain other fitting equations. The improvements of these technical solutions all fall within the scope of protection of the present invention.

Claims

1. A device for quickly detecting water content in oil, comprising an oil pipeline (1), characterized in that: The oil pipeline (1) is provided with a suction port (101) at one end, 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 transmitter (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).

2. The device for rapid detection of water content in oil according to claim 1, characterized in that: 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.

3. The device for rapid detection of water content in oil according to claim 1, characterized in that: The air chamber (11) is arranged between the infrared transmitter (13) and the receiver (6).

4. 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 (2011) is connected to a power divider (2012) via a data line, the power divider (2012) is connected to a microwave transmitting probe (202) via a data line, the power divider (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).

5. The device for rapid detection of water content in oil 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.

6. A calibration method for a rapid detection device for water content in oil according to any one of claims 1 to 5, characterized in that: The following steps are involved: S1, turning on the electronic control module 4, and injecting oils with different water contents into the oil pipeline 1 in batches; S1.1, 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; S1.2, the receiver 6 transmits the infrared signals of the oil with different water contents to the calibration analyzer 5 respectively; the calibration analyzer 5 converts the infrared signals into the mass water content y by infrared method and transmits them to the data acquisition unit 3; S2, the collection unit 3 collects the moisture content η in step S1.1 w And the mass moisture content y in step S1.2 is fitted to obtain y and η w The linear first-order calibration equation of .

7. The calibration method according to claim 6, characterized in that: In step S1.1, the mass moisture content η w The calculation formula is: 。 8. The calibration method according to claim 7, characterized in that: 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 water phase, L O is the thickness of the oil phase, Lg 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; 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 、V W 、V O is the volume of air, pure water and pure oil in the mixture.

9. The calibration method according to claim 6, 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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