Method for measuring natural degree in fuel oil based on three-pipe two-pipe coincidence ratio

Abstract

The invention provides a method for determining the natural degree of fuel oil based on a three-tube two-tube coincidence ratio, which comprises the following steps: putting a 14C sample and a blank sample into a three-tube liquid flash counter for measurement, calculating a TDCR value of 14C according to a measurement result, and fitting a relation curve of the TDCR value relative to the counting efficiency; the method comprises the following steps: measuring a biofuel sample and a fossil fuel sample in a three-tube liquid flash counter, calculating a TDCR value of the biofuel according to a measurement result, and correcting the counting efficiency of the biofuel according to a 14C counting efficiency formula; and measuring the carbon content in the biological fuel oil sample by using an element analyzer, and calculating the natural degree in the biological fuel oil according to the carbon content in the biological fuel oil sample. According to the method, efficiency correction is carried out through a three-tube coincidence and two-tube coincidence ratio method (TDCR), and the defect that efficiency correction is inaccurate due to the fact that color quenching and chemical quenching exist at the same time is effectively overcome.

Description

Technical Field

[0001] The present application relates to the technical field of biofuel naturalness detection, and in particular to a method for determining the naturalness of fuel based on a three-tube and two-tube coincidence ratio. Background Art

[0002] At present, the number of cars in my country is increasing, and the demand for fuel is also increasing. In order to use renewable energy, the country has promoted the use of bioethanol gasoline in many provinces, and directly subsidized the production cost of ethanol gasoline through fiscal subsidies to encourage the production and use of ethanol gasoline. For the aviation industry, under the background of the Carbon Offsetting and Reduction Scheme for International Aviation (CORSIA) and the EU aviation industry carbon reduction policy, the global aviation industry has policy regulations on carbon emission reduction. For the rapidly developing aviation industry, the development of renewable aviation fuel is considered to be the main measure to reduce carbon dioxide emissions. According to statistics, if 20% of biomass fuel is mixed with aviation gasoline, carbon emissions can be reduced by 50%, but the current price of biofuel (biofuel refers to fuel converted from biomass (such as plants, animals and microorganisms), mainly used to replace traditional fossil fuels) is much higher than that of fossil fuels. Therefore, it is necessary to establish a method to identify the natural content of fuel for effective supervision.

[0003] By measuring radionuclides 14 C (half-life 5730 years) analysis of naturalness in fuel is a widely recognized method of naturalness analysis. 14 C is mainly composed of 14 N is produced by cosmic ray irradiation and after the carbon cycle, 14 C activity and atmospheric 14 C remains the same. However, fossil fuels such as coal and oil are stored underground for a long time and undergo radioactive decay. 14 The C activity is close to zero, so it can be considered as the 14 C comes from the CO2 in the current atmosphere. The value of naturalness is the 14 The specific activity of C (radiocarbon).

[0004] 14 As a pure β-radioactive nuclide, the most commonly used measurement methods for C are accelerator mass spectrometry (AMS) and liquid scintillation counter (LSC). However, accelerator mass spectrometry is not popular in China at present, and AMS measurement is costly, sample preparation and measurement are relatively complicated, and its universality is low. LSC is a method that can meet the needs of most 14 The C sample can be accurately measured, and its detection limit meets the requirements of aviation fuel testing.

[0005] Current LSC measurements 14The C method is mainly a benzene synthesis method and a carbon dioxide (CO2) absorption method. The benzene synthesis method requires the sample to be converted into benzene, which involves multiple steps of chemical treatment. Due to the complexity of the experimental operation, each step will produce measurement deviations, resulting in a large comprehensive measurement deviation; the carbon dioxide absorption method requires the sample to be fully burned and then the CO2 gas is collected for measurement. However, during the sample preparation process, some carbon may be lost due to improper operation or incomplete chemical reaction, thus affecting the accuracy of the measurement results. Charles G. Doll et al. used the direct LSC method to measure gasoline and diesel. This method does not require a complex sample preparation process, and can directly mix the bio-based fuel sample with the scintillation liquid for measurement, simplifying the operation steps. However, the direct LSC method may be affected by the color or chemical composition of the sample, resulting in a decrease in the photon detection efficiency, thereby affecting the measurement accuracy. In order to accurately measure, each sample needs to be quenched. The original method uses an external standard source for quenching correction. When the sample has both chemical and color quenching, the error of this analysis method is large. Summary of the invention

[0006] In view of this, the present application provides a method for determining the naturalness of fuel based on the three-tube two-tube coincidence ratio, which solves the problem that the naturalness of fuel directly determined by the LSC method in the prior art may be affected by the color or chemical composition of the sample, resulting in reduced photon detection efficiency, thereby affecting the measurement accuracy. In order to ensure the accuracy of the measurement, each sample needs to be quenched and corrected. At this time, when the sample has both chemical and color quenching, it will cause a large error in the analysis method.

[0007] The present application provides a method for determining the naturalness of fuel oil based on the three-tube and two-tube coincidence ratio, comprising: preparing 14 C sample and blank sample, prepare 14 C sample and blank sample were stored in dark place for 0.01-60 hours, then put into three-tube liquid scintillation counter for measurement. 14 The TDCR value of C and the counting efficiency are based on 14 The TDCR value of C and the counting efficiency are fitted with the relationship curve of the TDCR value relative to the counting efficiency, and the formula of the counting efficiency is obtained according to the relationship curve of the fitted TDCR value relative to the counting efficiency;

[0008] Prepare the sample to be tested, add biofuel and scintillation fluid into the sample bottle to be tested;

[0009] Prepare background samples, add mineral fuel and scintillation liquid into the background sample bottle, store the sample to be tested and the background sample in a dark place for 0.01-60 hours, and then put them into a three-tube liquid scintillation counter for measurement. Calculate the TDCR value of biofuel based on the measurement results. 14 C counting efficiency formula corrects the counting efficiency of biofuel;

[0010] The carbon content in the biofuel sample is measured using an elemental analyzer, and the naturalness of the biofuel is calculated based on the carbon content in the biofuel sample.

[0011] Preferably, the test sample and the background sample are stored away from light for 4-24 hours;

[0012] Preferably, the 14 The C sample and the blank sample were stored away from light for 4-24 hours.

[0013] Preferably, the formulation 14 C sample includes: adding scintillation fluid, background material, 14 C standard substance and quencher of different concentrations; and / or, preparing blank samples includes: adding scintillation fluid, background substance and quencher of different concentrations into blank sample bottles.

[0014] Preferably, the 14 C sample 14 The concentration of C standard substance is 300-5000 Bg / g; and / or, 14 C sample 14 The activity of the C standard substance is greater than 0.1 Bq; and / or, 14 The measurement time of C sample is 2-120 minutes.

[0015] Preferably, the background material is one of mineral oil or hexadecane.

[0016] Preferably, the quencher is any one of a dye, nitromethane, and carbon black. 14 The concentrations of the quencher in the C sample or the blank sample are 0, 0.01%, 0.05%, 0.1%, and 0.2%.

[0017] Preferably, the calculation according to the measurement results 14 The TDCR value of C includes: Calculated according to formula (1) 14 TDCR value of C

[0018]

[0019] Among them, in formula (1):

[0020] T stands for 14 The three tubes of sample C meet the count;

[0021] T B The three tubes representing the blank sample coincide with the count;

[0022] D stands for 14 The two tubes of sample C meet the counts;

[0023] D B The two tubes representing blank samples matched the counts.

[0024] Preferably, the calculation according to the measurement results 14 The counting efficiency of C includes: Calculate the counting efficiency according to formula (2):

[0025]

[0026] Among them, in formula (2):

[0027] E stands for 14 C The counting efficiency of the sample;

[0028] D stands for 14 The two tubes of sample C met the counts;

[0029] D B The two tubes representing the blank sample conform to the count;

[0030] A means 14 C The activity of the sample;

[0031] T stands for 14 C The measurement duration of the sample.

[0032] Preferably, the volume ratio of the biofuel and the scintillation fluid added is 1-(0.5:1).

[0033] Preferably, the step of calculating the TDCR value of the biofuel according to the measurement results comprises: calculating the TDCR value of the biofuel according to formula (3):

[0034]

[0035] Among them, in formula (3):

[0036] T BF Three tubes of compliance count for biofuels;

[0037] T FF Three tubes for fossil fuels meet the count;

[0038] D BF Two tubes of biofuel meet the count,

[0039] D FF Two tubes for fossil fuels meet the count.

[0040] Preferably, the natural content of the biofuel sample is calculated based on the measurement results.

[0041]

[0042] Among them, in formula (4):

[0043] N represents the natural content of the sample;

[0044] D BF Two tubes of biofuel meet the count;

[0045] D FF Two tubes for fossil fuels meet the count;

[0046] E is the counting efficiency;

[0047] T is the measurement time;

[0048] m represents the mass of the added aviation fuel sample;

[0049] ω represents the carbon content of the sample.

[0050] The present application provides a method for determining the naturalness of fuel oil based on the three-tube and two-tube coincidence ratio, comprising: 14 After the C sample and the blank sample were stored in the dark for a certain period of time, they were placed in a three-tube liquid scintillation counter for measurement. 14 The TDCR value of C and the counting efficiency are based on 14 The TDCR value of C and the counting efficiency are fitted with the relationship curve of TDCR value relative to counting efficiency, and the formula of counting efficiency is obtained according to the relationship curve of TDCR value relative to counting efficiency fitted; after the biofuel sample and the fossil fuel sample are stored in the dark for a certain period of time, they are placed in a three-tube liquid scintillation counter for measurement, and the TDCR value of the biofuel is calculated according to the measurement results. 14 The counting efficiency of biofuel is corrected by using the C counting efficiency formula; the carbon content in the biofuel sample is measured by an elemental analyzer, and the natural degree in the biofuel is calculated based on the carbon content in the biofuel sample. The present application uses the three-tube coincidence and two-tube coincidence ratio method (TDCR) to perform efficiency correction, effectively avoiding the inaccuracy of efficiency correction due to the coexistence of color quenching and chemical quenching. Compared with the traditional benzene synthesis method, the operation is simpler and manpower is saved. Compared with AMS, expensive instruments and equipment are not required, and hardware conditions are reduced. BRIEF DESCRIPTION OF THE DRAWINGS

[0051] Figure 1 The example 1 of the present application is shown as follows 14 C counting efficiency relationship curve;

[0052] Figure 2 The example 2 of this application is shown. 14 C counting efficiency relationship curve;

[0053] Figure 3 The example 3 of the present application provides 14C counting efficiency relationship curve;

[0054] Figure 4 The example 4 of the present application is shown. 14 C counting efficiency relationship curve;

[0055] Figure 5 The example 5 of the present application is shown. 14 C counting efficiency relationship curve;

[0056] Figure 6 The example 6 of the present application is shown. 14 C counting efficiency relationship curve; Figure 7 The example 7 of the present application is shown. 14 C counting efficiency relationship curve. DETAILED DESCRIPTION

[0057] In order to make the purpose, technical solution and advantages of the present invention clearer, the technical solution of the present invention will be clearly and completely described below in conjunction with the specific embodiments of the present invention and the corresponding drawings. In the description of the present invention, it should be noted that the term "or" is usually used in the sense of including "and / or", unless the content clearly indicates otherwise.

[0058] Example 1

[0059] Preparation 14 C sample: add 10 mL of scintillation fluid and 10 mL of mineral oil to a 20 mL liquid scintillation bottle, add 0.1 mL of 14 C radioactive standard substances, 14 C radioactive standard substances 14 The concentration of sample C is 300 Bg / g, and then different concentrations of yellow pigment are added to prepare 5 different concentrations of 14 Sample C, yellow pigment in 14 The concentrations of the C samples were 0%, 0.01%, 0.05%, 0.1%, and 0.2%. After mixing evenly, the mixture was kept away from light for 12 hours, and then 5 samples containing different concentrations of yellow pigment were placed on the 14 C samples were placed in a three-tube liquid scintillation counter (Hidex300SL) for each 14 The C sample was measured for 10 minutes. 14 The three tubes of sample C are consistent with the count and 14 The two tubes of sample C are consistent with the count;

[0060] Prepare blank samples: Add 10 mL of scintillation fluid and 10 mL of mineral oil to a 20 mL liquid scintillation bottle, and then add different concentrations of yellow pigment to prepare 5 different concentrations of 14 Sample C, yellow pigment in14 The concentrations of C samples were 0%, 0.01%, 0.05%, 0.1%, and 0.2%, respectively. After being mixed evenly and stored away from light for 12 hours, 5 blank samples containing different concentrations of yellow pigment were placed in a three-tube liquid scintillation counter (Hidex300SL) to measure each blank sample for 10 minutes, and the three-tube coincidence counts of the blank sample and the two-tube coincidence counts of the blank sample were measured;

[0061] According to the measured 14 The three tubes of sample C are consistent with the count and 14 The TDCR value of each sample is calculated according to formula (1) based on the coincidence count of two tubes of C sample, the coincidence count of three tubes of blank sample and the coincidence count of two tubes of blank sample;

[0062]

[0063] In formula (1), T represents 14 C sample three tubes meet the count; T B The three tubes of blank sample are counted; D indicates 14 C sample two tubes meet the count; D B The two tubes representing the blank sample are consistent with the count. 14 The TDCR values ​​of sample C are 0.959, 0.941, 0.921, 0.893 and 0.847, respectively.

[0064] Calculated based on the measurement results 14 The counting efficiency of C includes: Calculate the counting efficiency according to formula (2):

[0065]

[0066] Among them, in formula (2):

[0067] E stands for 14 C The counting efficiency of the sample;

[0068] D stands for 14 The two tubes of sample C met the counts;

[0069] D B The two tubes representing the blank sample conform to the count;

[0070] A means 14 C The activity of the sample;

[0071] T stands for 14 C The measurement duration of the sample.

[0072] After calculation, five 14The counting efficiencies of sample C are 0.952, 0.940, 0.921, 0.898 and 0.872 respectively. The relationship between TDCR value and counting efficiency is fitted according to the calculated TDCR value and counting efficiency. Figure 1 The example 1 of the present application is shown as follows 14 C counting efficiency relationship curve, such as Figure 1 As shown, according to the relationship between TDCR value and counting efficiency, 14 The counting efficiency formula of C is E=1.0970-1.1499*TDCR+1.0414*TDCR 2 .

[0073] Measurement of biofuel samples:

[0074] Add 10 ml of aviation fuel and 10 ml of scintillation fluid to a 20 ml glass bottle or liquid scintillation bottle, mix well and place in a dark place for 12 hours as the sample to be tested;

[0075] Add 10 ml of No. 10 mineral oil and 10 ml of scintillation fluid to a 20 ml glass liquid bottle or liquid scintillation bottle, mix well and place in a dark place for 12 hours as a background sample;

[0076] The background sample and the sample to be tested were placed in a three-tube liquid scintillation counter (Hidex300SL) for measurement for 4 hours. The two-tube coincidence count data and the three-tube coincidence count data of the background sample and the sample to be tested were obtained. The TDCR value of the aviation fuel was calculated according to formula (3):

[0077]

[0078] In formula (3), T BF Three tubes for biofuels are counted; T FF Three tubes of fossil fuels are counted; D BF Two tubes of biofuel meet the count, D FF Two tubes for fossil fuels meet the count.

[0079] According to the fitting 14 The counting efficiency formula of C is E=1.0970-1.1499*TDCR+1.0414*TDCR 2 Calculate the counting efficiency of the sample to be tested.

[0080] The carbon content in the sample to be tested was measured by an element analyzer and was found to be 85.1%. The natural content of the aviation fuel in the sample to be tested was calculated according to formula (4).

[0081]

[0082] Wherein, in formula (4): N represents the natural content of the sample; D BF Two tubes of biofuel meet the count; D FF is the coincidence count of the two tubes of fossil fuel; E is the counting efficiency; T is the measurement time; m is the mass of the added aviation fuel sample; ω is the carbon content of the sample. According to Formula 4, the naturalness of the aviation fuel in Example 1 is 98%.

[0083] Example 2

[0084] Preparation 14 C sample: add 10 mL of scintillation fluid and 10 mL of hexadecane to a 20 mL liquid scintillation vial, add 0.05 mL of 14 C radioactive standard substances, 14 C radioactive standard substances 14 The concentration of sample C is 5000 Bg / g, and then different volumes of nitromethane are added to prepare 5 samples with different nitromethane concentrations. 14 Sample C, the volume of nitromethane is 0, 0.01, 0.04, 0.07, 0.1 microliters. Then mix well, keep away from light for 4 hours, and then add different volumes of nitromethane to the 5 14 C samples were placed in a three-tube liquid scintillation counter (Hidex300SL) for each 14 C sample was measured for 2 hours, and the results were 14 The three tubes of sample C are consistent with the count and 14 The two tubes of sample C are consistent with the count;

[0085] Prepare blank samples: Add 10 mL of scintillation fluid and 10 mL of mineral oil to a 20 mL liquid scintillation vial, and then add different volumes of nitromethane to prepare 5 different concentrations of 14 C sample, nitromethane in 14 The concentrations of C in the samples were 0%, 0.01%, 0.05%, 0.1%, and 0.2%, respectively. After being mixed evenly and stored away from light for 4 hours, 5 blank samples containing different volumes of nitromethane were placed in a three-tube liquid scintillation counter (Hidex300SL) to measure each blank sample for 2 hours, and the three-tube coincidence counts of the blank sample and the two-tube coincidence counts of the blank sample were measured;

[0086] According to the measured 14 The three tubes of sample C are consistent with the count and 14 The TDCR value of each sample is calculated according to formula (1) based on the coincidence count of two tubes of C sample, the coincidence count of three tubes of blank sample and the coincidence count of two tubes of blank sample;

[0087]

[0088] In formula (1), T represents 14 C sample three tubes meet the count; T B The three tubes of blank sample are counted; D indicates 14 C sample two tubes meet the count; D B The two tubes representing the blank sample are consistent with the count. 14 The TDCR values ​​of sample C are 0.96329, 0.93378, 0.89566, 0.83539 and 0.79324, respectively.

[0089] Calculated based on the measurement results 14 The counting efficiency of C includes: Calculate the counting efficiency according to formula (2):

[0090]

[0091] Among them, in formula (2):

[0092] E stands for 14 C The counting efficiency of the sample;

[0093] D stands for 14 The two tubes of sample C met the counts;

[0094] D B The two tubes representing the blank sample conform to the count;

[0095] A means 14 C The activity of the sample;

[0096] T stands for 14 C The measurement duration of the sample.

[0097] After calculation, five 14 The counting efficiencies of sample C are 0.96329, 0.93378, 0.89566, 0.83539, and 0.79324, respectively. The relationship between the TDCR value and the counting efficiency is fitted based on the calculated TDCR value and the counting efficiency. Figure 2 The example 2 of this application is shown. 14 C counting efficiency relationship curve, such as Figure 2 As shown, according to the relationship between TDCR value and counting efficiency, 14 The counting efficiency formula of C is E=0.5158+0.1059*TDCR+0.3542*TDCR 2 .

[0098] Measurement of biofuel samples:

[0099] Add 10 ml of aviation fuel and 10 ml of scintillation fluid to a 20 ml glass bottle or liquid scintillation bottle, mix well and place in a dark place for 4 hours as the sample to be tested;

[0100] Add 10 ml of No. 100 mineral oil and 10 ml of scintillation fluid to a 20 ml glass liquid bottle or liquid scintillation bottle, mix well and place in a dark place for 4 hours as a background sample;

[0101] The background sample and the sample to be tested were placed in a three-tube liquid scintillation counter (Hidex300SL) for measurement for 4 hours. The two-tube coincidence count data and the three-tube coincidence count data of the background sample and the sample to be tested were obtained. The TDCR value of the aviation fuel was calculated according to formula (3):

[0102]

[0103] In formula (3), T BF Three tubes for biofuels are counted; T FF Three tubes of fossil fuels are counted; D BF Two tubes of biofuel meet the count, D FF Two tubes for fossil fuels meet the count.

[0104] According to the fitting 14 The counting efficiency formula of C is E=1.0970-1.1499*TDCR+1.0414*TDCR 2 Calculate the counting efficiency of the sample to be tested.

[0105] The carbon content in the sample to be tested was measured by an element analyzer and was found to be 85.1%. The natural content of the aviation fuel in the sample to be tested was calculated according to formula (4).

[0106]

[0107] Wherein, in formula (4): N represents the natural content of the sample; D BF Two tubes of biofuel meet the count; D FF is the coincidence count of the two tubes of fossil fuel; E is the counting efficiency; T is the measurement time; m is the mass of the added aviation fuel sample; ω is the carbon content of the sample. According to formula 4, the naturalness of the aviation fuel in Example 2 is 99.8%.

[0108] Example 3

[0109] Preparation 14 C sample: Add 10 mL of scintillation fluid and 10 mL of mineral oil to a 20 mL liquid scintillation bottle, add 0.05 mL of 14 C radioactive standard substances, 14 C radioactive standard substances 14 The concentration of sample C is 5000 Bg / g, and then different volumes of carbon black are added to prepare 5 different degrees of 14Sample C, the weight of carbon black is 0, 0.01, 0.02, 0.06 and 0.1g. Then, after mixing evenly, keep it away from light for 12 hours, and then add five samples with different concentrations of carbon black. 14 C samples were placed in a three-tube liquid scintillation counter (Hidex300SL) for each 14 C sample was measured for 1 hour, and the results were 14 The three tubes of sample C are consistent with the count and 14 The two tubes of sample C are consistent with the count;

[0110] Prepare blank samples: add 10mL of scintillation fluid and 10mL of mineral oil to a 20mL liquid scintillation bottle, and then add different weights of carbon black 0, 0.01, 0.02, 0.06 and 0.1g to prepare 5 blank samples of different concentrations. Then mix well, store in dark for 12 hours, put the 5 blank samples of different concentrations into a three-tube liquid scintillation counter (Hidex300SL) to measure each blank sample for 1 hour, and measure the three-tube coincidence count of the blank sample and the two-tube coincidence count of the blank sample;

[0111] According to the measured 14 The three tubes of sample C are consistent with the count and 14 The TDCR value of each sample is calculated according to formula (1) based on the coincidence count of two tubes of C sample, the coincidence count of three tubes of blank sample and the coincidence count of two tubes of blank sample;

[0112]

[0113] In formula (1), T represents 14 C sample three tubes meet the count; T B The three tubes of blank sample are counted; D indicates 14 C sample two tubes meet the count; D B The two tubes representing the blank sample are consistent with the count. 14 The TDCR values ​​of sample C are 0.9611, 0.9321, 0.8993, 0.8212, and 0.6505, respectively.

[0114] Calculated based on the measurement results 14 The counting efficiency of C includes: Calculate the counting efficiency according to formula (2):

[0115]

[0116] Among them, in formula (2):

[0117] E stands for 14 C The counting efficiency of the sample;

[0118] D stands for14 The two tubes of sample C met the counts;

[0119] D B The two tubes representing the blank sample conform to the count;

[0120] A means 14 C The activity of the sample;

[0121] T stands for 14 C The measurement duration of the sample.

[0122] After calculation, five 14 The counting efficiencies of sample C are 0.9639, 0.9387, 0.9051, 0.8289, and 0.6938, respectively. The relationship between the TDCR value and the counting efficiency is fitted according to the calculated TDCR value and the counting efficiency. Figure 3 The example 3 of the present application provides 14 C counting efficiency relationship curve, such as Figure 3 As shown, according to the relationship between TDCR value and counting efficiency, 14 The counting efficiency formula of C is E=0.4573+0.01463*TDCR+0.53565*TDCR 2 .

[0123] Measurement of biofuel samples:

[0124] Add 10 ml of aviation fuel and 10 ml of scintillation fluid to a 20 ml glass bottle or liquid scintillation bottle, mix well and place in a dark place for 12 hours as the sample to be tested;

[0125] Add 10 ml of No. 50 mineral oil and 10 ml of scintillation fluid to a 20 ml glass liquid bottle or liquid scintillation bottle, mix well and place in a dark place for 12 hours as a background sample;

[0126] The background sample and the sample to be tested were placed in a three-tube liquid scintillation counter (Hidex300SL) for measurement for 4 hours. The two-tube coincidence count data and the three-tube coincidence count data of the background sample and the sample to be tested were obtained. The TDCR value of the aviation fuel was calculated according to formula (3):

[0127]

[0128] In formula (3), T BF Three tubes for biofuels are counted; T FF Three tubes of fossil fuels are counted; D BF Two tubes of biofuel meet the count, D FF Two tubes for fossil fuels meet the count.

[0129] According to the fitting14 The counting efficiency formula of C is E=0.4573+0.01463*TDCR+0.53565*TDCR 2 Calculate the counting efficiency of the sample to be tested.

[0130] The carbon content in the sample to be tested was measured by an element analyzer and was found to be 85.1%. The natural content of the aviation fuel in the sample to be tested was calculated according to formula (4).

[0131]

[0132] Wherein, in formula (4): N represents the natural content of the sample; D BF Two tubes of biofuel meet the count; D FF is the coincidence count of the two tubes of fossil fuel; E is the counting efficiency; T is the measurement time; m is the mass of the added aviation fuel sample; ω is the carbon content of the sample. According to Formula 4, the naturalness of the aviation fuel in Example 3 is 99.9%.

[0133] Example 4

[0134] Preparation 14 C sample: Add 10 mL of scintillation fluid and 10 mL of mineral oil to a 20 mL liquid scintillation bottle, add 0.01 mL of 14 C radioactive standard substances, 14 C radioactive standard substances 14 The concentration of sample C is 1000 Bg / g, and then different volumes of yellow pigment are added to prepare 5 different concentrations. 14 Sample C, yellow pigment in 14 The concentrations of the C samples were 0%, 0.01%, 0.05%, 0.1%, and 0.2%. After mixing evenly, the mixture was kept away from light for 24 hours, and then 5 samples with different concentrations of carbon black were added. 14 C samples were placed in a three-tube liquid scintillation counter (Hidex300SL) for each 14 C sample was measured for 20 minutes, and the results were 14 The three tubes of sample C are consistent with the count and 14 The two tubes of sample C are consistent with the count;

[0135] Prepare blank samples: add 10 mL of scintillation fluid and 10 mL of mineral oil to a 20 mL liquid scintillation bottle, and then add different volumes of yellow pigment to prepare 5 blank samples with different concentrations. The concentrations of yellow pigment in the blank samples are: 14The concentrations of C samples were 0%, 0.01%, 0.05%, 0.1%, and 0.2%, respectively. After being mixed evenly and stored away from light for 24 hours, 5 blank samples with different concentrations were placed in a three-tube liquid scintillation counter (Hidex300SL) to measure each blank sample for 20 minutes, and the three-tube coincidence counts of the blank sample and the two-tube coincidence counts of the blank sample were measured;

[0136] According to the measured 14 The three tubes of sample C are consistent with the count and 14 The TDCR value of each sample is calculated according to formula (1) based on the coincidence count of two tubes of C sample, the coincidence count of three tubes of blank sample and the coincidence count of two tubes of blank sample;

[0137]

[0138] In formula (1), T represents 14 C sample three tubes meet the count; T B The three tubes of blank sample are counted; D indicates 14 C sample two tubes meet the count; D B The two tubes representing the blank sample are consistent with the count. 14 The TDCR values ​​of sample C are 0.9653, 0.9223, 0.9113, 0.8823 and 0.8723, respectively.

[0139] Calculated based on the measurement results 14 The counting efficiency of C includes: Calculate the counting efficiency according to formula (2):

[0140]

[0141] Among them, in formula (2):

[0142] E stands for 14 C The counting efficiency of the sample;

[0143] D stands for 14 The two tubes of sample C met the counts;

[0144] D B The two tubes representing the blank sample conform to the count;

[0145] A means 14 C The activity of the sample;

[0146] T stands for 14 C The measurement duration of the sample.

[0147] After calculation, five 14The counting efficiencies of sample C are 0.9653, 0.9223, 0.9113, 0.8823 and 0.8723 respectively. The relationship between TDCR value and counting efficiency is fitted according to the calculated TDCR value and counting efficiency. Figure 4 The example 4 of the present application is shown. 14 C counting efficiency relationship curve, such as Figure 4 As shown, according to the relationship between TDCR value and counting efficiency, 14 The counting efficiency formula of C is E=-2.0686*TDCR 2 +4.5911*TDCR-1.5583.

[0148] Measurement of biofuel samples:

[0149] Add 10 ml of aviation fuel and 10 ml of scintillation fluid to a 20 ml glass bottle or liquid scintillation bottle, mix well and place in a dark place for 24 hours as the sample to be tested;

[0150] Add 10 ml of No. 10 mineral oil and 10 ml of scintillation fluid to a 20 ml glass liquid bottle or liquid scintillation bottle, mix well and place in a dark place for 24 hours as a background sample;

[0151] The background sample and the sample to be tested were placed in a three-tube liquid scintillation counter (Hidex300SL) for measurement for 4 hours. The two-tube coincidence count data and the three-tube coincidence count data of the background sample and the sample to be tested were obtained. The TDCR value of the biofuel was calculated according to formula (3):

[0152]

[0153] In formula (3), T BF Three tubes for biofuels are counted; T FF Three tubes of fossil fuels are counted; D BF Two tubes of biofuel meet the count, D FF Two tubes for fossil fuels meet the count.

[0154] According to the fitting 14 The counting efficiency formula of C is E=-2.0686*TDCR 2 +4.5911*TDCR-1.5583 calculates the counting efficiency of the sample to be tested.

[0155] The carbon content in the sample to be tested was measured by an element analyzer and was found to be 85.1%. The natural content of the biofuel in the sample to be tested was calculated according to formula (4).

[0156]

[0157] Wherein, in formula (4): N represents the natural content of the sample; D BF Two tubes of biofuel meet the count; D FF is the coincidence count of the two tubes of fossil fuel; E is the counting efficiency; T is the measurement time; m is the mass of the added aviation fuel sample; ω is the carbon content of the sample. According to Formula 4, the naturalness of the aviation fuel in Example 4 is calculated to be 98.5%.

[0158] Example 5

[0159] Preparation 14 C sample: add 10 mL of scintillation fluid and 10 mL of mineral oil to a 20 mL liquid scintillation bottle, add 0.02 mL of 14 C radioactive standard substances, 14 C radioactive standard substances 14 The concentration of sample C is 2000 Bg / g, and then different volumes of yellow pigment are added to prepare 5 different concentrations. 14 Sample C, yellow pigment in 14 The concentrations of the C samples were 0%, 0.01%, 0.05%, 0.1%, and 0.2%. After mixing evenly, the mixture was kept away from light for 12 hours, and then 5 samples with different concentrations of carbon black were added. 14 C samples were placed in a three-tube liquid scintillation counter (Hidex300SL) for each 14 C sample was measured for 30 minutes, and the results were 14 The three tubes of sample C are consistent with the count and 14 The two tubes of sample C are consistent with the count;

[0160] Prepare blank samples: add 10 mL of scintillation fluid and 10 mL of mineral oil to a 20 mL liquid scintillation bottle, and then add different volumes of yellow pigment to prepare 5 blank samples with different concentrations. The concentrations of yellow pigment in the blank samples are: 14 The concentrations of C samples were 0%, 0.01%, 0.05%, 0.1%, and 0.15%, respectively. After being mixed evenly and stored away from light for 12 hours, 5 blank samples with different concentrations were placed in a three-tube liquid scintillation counter (Hidex300SL) to measure each blank sample for 30 minutes, and the three-tube coincidence counts of the blank sample and the two-tube coincidence counts of the blank sample were measured;

[0161] According to the measured 14 The three tubes of sample C are consistent with the count and 14 The TDCR value of each sample is calculated according to formula (1) based on the coincidence count of two tubes of C sample, the coincidence count of three tubes of blank sample and the coincidence count of two tubes of blank sample;

[0162]

[0163] In formula (1), T represents 14 C sample three tubes meet the count; T B The three tubes of blank sample are counted; D indicates 14 C sample two tubes meet the count; D B The two tubes representing the blank sample are consistent with the count. 14 The TDCR values ​​of sample C are 0.9630, 0.9223, 0.9013, 0.8823, and 0.8623, respectively.

[0164] Calculated based on the measurement results 14 The counting efficiency of C includes: Calculate the counting efficiency according to formula (2):

[0165]

[0166] Among them, in formula (2):

[0167] E stands for 14 C The counting efficiency of the sample;

[0168] D stands for 14 The two tubes of sample C met the counts;

[0169] D B The two tubes representing the blank sample conform to the count;

[0170] A means 14 C The activity of the sample;

[0171] T stands for 14 C The measurement duration of the sample.

[0172] After calculation, five 14 The counting efficiencies of sample C are 0.9630, 0.9223, 0.9013, 0.8823, and 0.8623, respectively. The relationship between the TDCR value and the counting efficiency is fitted according to the calculated TDCR value and the counting efficiency. Figure 5 The example 5 of the present application is shown. 14 C counting efficiency relationship curve, such as Figure 5 As shown, according to the relationship between TDCR value and counting efficiency, 14 The counting efficiency formula of C is E=0.6182-0.1214*TDCR+0.4799*TDCR.

[0173] Measurement of biofuel samples:

[0174] Add 10 ml of aviation fuel and 10 ml of scintillation fluid to a 20 ml glass bottle or liquid scintillation bottle, mix well and place in a dark place for 12 hours as the sample to be tested;

[0175] Add 10 ml of No. 10 mineral oil and 10 ml of scintillation fluid to a 20 ml glass liquid bottle or liquid scintillation bottle, mix well and place in a dark place for 12 hours as a background sample;

[0176] The background sample and the sample to be tested were placed in a three-tube liquid scintillation counter (Hidex300SL) for measurement for 4 hours. The two-tube coincidence count data and the three-tube coincidence count data of the background sample and the sample to be tested were obtained. The TDCR value of the biofuel was calculated according to formula (3):

[0177]

[0178] In formula (3), T BF Three tubes for biofuels are counted; T FF Three tubes of fossil fuels are counted; D BF Two tubes of biofuel meet the count, D FF Two tubes for fossil fuels meet the count.

[0179] According to the fitting 14 The counting efficiency formula of C is E=0.6182-0.1214*TDCR+0.4799*TDCR to calculate the counting efficiency of the sample to be tested.

[0180] The carbon content in the sample to be tested was measured by an element analyzer and was found to be 85.1%. The natural content of the biofuel in the sample to be tested was calculated according to formula (4).

[0181]

[0182] Wherein, in formula (4): N represents the natural content of the sample; D BF Two tubes of biofuel meet the count; D FF is the coincidence count of the two tubes of fossil fuel; E is the counting efficiency; T is the measurement time; m is the mass of the added aviation fuel sample; ω is the carbon content of the sample. According to formula 4, the naturalness of the aviation fuel in Example 5 is calculated to be 98.9%.

[0183] Example 6

[0184] Preparation 14 C sample: add 10 mL of scintillation fluid and 10 mL of mineral oil to a 20 mL liquid scintillation bottle, add 0.03 mL of 14 C radioactive standard substances, 14 C radioactive standard substances 14 The concentration of sample C is 3000 Bg / g, and then different volumes of yellow pigment are added to prepare 5 different concentrations. 14 Sample C, yellow pigment in14 The concentrations of the C samples were 0%, 0.01%, 0.05%, 0.1%, and 0.2%. After mixing evenly, the mixture was kept away from light for 12 hours, and then 5 samples with different concentrations of carbon black were added. 14 C samples were placed in a three-tube liquid scintillation counter (Hidex300SL) for each 14 The C sample was measured for 10 minutes and the results were 14 The three tubes of sample C are consistent with the count and 14 The two tubes of sample C are consistent with the count;

[0185] Prepare blank samples: add 10 mL of scintillation fluid and 10 mL of mineral oil to a 20 mL liquid scintillation bottle, and then add different volumes of yellow pigment to prepare 5 blank samples with different concentrations. The concentrations of yellow pigment in the blank samples are: 14 The concentrations of C samples were 0%, 0.01%, 0.05%, 0.1%, and 0.18%, respectively. After being mixed evenly and stored away from light for 12 hours, 5 blank samples with different concentrations were placed in a three-tube liquid scintillation counter (Hidex300SL) to measure each blank sample for 10 minutes, and the three-tube coincidence counts of the blank sample and the two-tube coincidence counts of the blank sample were measured;

[0186] According to the measured 14 The three tubes of sample C are consistent with the count and 14 The TDCR value of each sample is calculated according to formula (1) based on the coincidence count of two tubes of C sample, the coincidence count of three tubes of blank sample and the coincidence count of two tubes of blank sample;

[0187]

[0188] In formula (1), T represents 14 C sample three tubes meet the count; T B The three tubes of blank sample are counted; D indicates 14 C sample two tubes meet the count; D B The two tubes representing the blank sample are consistent with the count. 14 The TDCR values ​​of sample C are 0.9621, 0.9321, 0.8903, 0.8741, and 0.8623, respectively.

[0189] Calculated based on the measurement results 14 The counting efficiency of C includes: Calculate the counting efficiency according to formula (2):

[0190]

[0191] Among them, in formula (2):

[0192] E stands for 14 C The counting efficiency of the sample;

[0193] D stands for 14 The two tubes of sample C met the counts;

[0194] D B The two tubes representing the blank sample conform to the count;

[0195] A means 14 C The activity of the sample;

[0196] T stands for 14 C The measurement duration of the sample.

[0197] After calculation, five 14 The counting efficiencies of sample C are 0.9621, 0.9321, 0.8903, 0.8741, and 0.8623, respectively. The relationship between the TDCR value and the counting efficiency is fitted according to the calculated TDCR value and the counting efficiency. Figure 6 The example 1 of the present application is shown as follows 14 C counting efficiency relationship curve, such as Figure 6 As shown, according to the relationship between TDCR value and counting efficiency, 14 The counting efficiency formula of C is E=0.3689+0.4350*TDCR+0.1702*TDCR.

[0198] Measurement of biofuel samples:

[0199] Add 10 ml of aviation fuel and 10 ml of scintillation fluid to a 20 ml glass bottle or liquid scintillation bottle, mix well and place in a dark place for 12 hours as the sample to be tested;

[0200] Add 10 ml of mineral oil 991 and 10 ml of scintillation fluid to a 20 ml glass liquid bottle or liquid scintillation bottle, mix well and place in a dark place for 12 hours as a background sample;

[0201] The background sample and the sample to be tested were placed in a three-tube liquid scintillation counter (Hidex300SL) for measurement for 4 hours. The two-tube coincidence count data and the three-tube coincidence count data of the background sample and the sample to be tested were obtained. The TDCR value of the biofuel was calculated according to formula (3):

[0202]

[0203] In formula (3), T BF Three tubes for biofuels are counted; T FF Three tubes of fossil fuels are counted; D BF Two tubes of biofuel meet the count, DFF Two tubes for fossil fuels meet the count.

[0204] According to the fitting 14 The counting efficiency formula of C is E=0.3689+0.4350*TDCR+0.1702*TDCR to calculate the counting efficiency of the sample to be tested.

[0205] The carbon content in the sample to be tested was measured by an element analyzer and was found to be 85.1%. The natural content of the biofuel in the sample to be tested was calculated according to formula (4).

[0206]

[0207] Wherein, in formula (4): N represents the natural content of the sample; D BF Two tubes of biofuel meet the count; D FF is the coincidence count of the two tubes of fossil fuel; E is the counting efficiency; T is the measurement time; m is the mass of the added aviation fuel sample; ω is the carbon content of the sample. According to Formula 4, the naturalness of the aviation fuel in Example 3 is 100%.

[0208] Example 7

[0209] Preparation 14 C sample: add 10 mL of scintillation fluid and 10 mL of mineral oil to a 20 mL liquid scintillation bottle, add 0.04 mL of 14 C radioactive standard substances, 14 C radioactive standard substances 14 The concentration of sample C is 4000 Bg / g, and five samples with different concentrations are prepared by adding different volumes of yellow pigment. 14 Sample C, yellow pigment in 14 The concentrations of the C samples were 0%, 0.01%, 0.05%, 0.1%, and 0.2%. After mixing evenly, the mixture was kept away from light for 12 hours, and then 5 samples with different concentrations of carbon black were added. 14 C samples were placed in a three-tube liquid scintillation counter (Hidex300SL) for each 14 C sample was measured for 30 minutes, and the results were 14 The three tubes of sample C are consistent with the count and 14 The two tubes of sample C are consistent with the count;

[0210] Prepare blank samples: add 10 mL of scintillation fluid and 10 mL of mineral oil to a 20 mL liquid scintillation bottle, and then add different volumes of yellow pigment to prepare 5 blank samples with different concentrations. The concentrations of yellow pigment in the blank samples are: 14The concentrations of C samples were 0%, 0.01%, 0.07%, 0.15%, and 0.3%, respectively. After being mixed evenly and stored away from light for 12 hours, 5 blank samples with different concentrations were placed in a three-tube liquid scintillation counter (Hidex300SL) to measure each blank sample for 30 minutes, and the three-tube coincidence counts of the blank sample and the two-tube coincidence counts of the blank sample were measured;

[0211] According to the measured 14 The three tubes of sample C are consistent with the count and 14 The TDCR value of each sample is calculated according to formula (1) based on the coincidence count of two tubes of C sample, the coincidence count of three tubes of blank sample and the coincidence count of two tubes of blank sample;

[0212]

[0213] In formula (1), T represents 14 C sample three tubes meet the count; T B The three tubes of blank sample are counted; D indicates 14 C sample two tubes meet the count; D B The two tubes representing the blank sample are consistent with the count. 14 The TDCR values ​​of sample C are 0.9615, 0.9132, 0.8823, 0.8161, and 0.7871, respectively.

[0214] Calculated based on the measurement results 14 The counting efficiency of C includes: Calculate the counting efficiency according to formula (2):

[0215]

[0216] Among them, in formula (2):

[0217] E stands for 14 C The counting efficiency of the sample;

[0218] D stands for 14 The two tubes of sample C met the counts;

[0219] D B The two tubes representing the blank sample conform to the count;

[0220] A means 14 C The activity of the sample;

[0221] T stands for 14 C The measurement duration of the sample.

[0222] After calculation, five 14The counting efficiencies of sample C are 0.9615, 0.9132, 0.8823, 0.8161, and 0.7871, respectively. The relationship between the TDCR value and the counting efficiency is fitted according to the calculated TDCR value and the counting efficiency. Figure 7 The example 6 of the present application is shown. 14 C counting efficiency relationship curve, such as Figure 7 As shown, according to the relationship between TDCR value and counting efficiency, 14 The counting efficiency formula of C is E=0.4971+0.1504*TDCR+0.3279*TDCR.

[0223] Measurement of biofuel samples:

[0224] Add 10 ml of aviation fuel and 10 ml of scintillation fluid to a 20 ml glass bottle or liquid scintillation bottle, mix well and place in a dark place for 12 hours as the sample to be tested;

[0225] Add 10 ml of No. 10 mineral oil and 10 ml of scintillation fluid to a 20 ml glass liquid bottle or liquid scintillation bottle, mix well and place in a dark place for 12 hours as a background sample;

[0226] The background sample and the sample to be tested were placed in a three-tube liquid scintillation counter (Hidex300SL) for measurement for 4 hours. The two-tube coincidence count data and the three-tube coincidence count data of the background sample and the sample to be tested were obtained. The TDCR value of the biofuel was calculated according to formula (3):

[0227]

[0228] In formula (3), T BF Three tubes for biofuels are counted; T FF Three tubes of fossil fuels are counted; D BF Two tubes of biofuel meet the count, D FF Two tubes for fossil fuels meet the count.

[0229] According to the fitting 14 The counting efficiency formula of C is E=0.4971+0.1504*TDCR+0.3279*TDCR to calculate the counting efficiency of the sample to be tested.

[0230] The carbon content in the sample to be tested was measured by an element analyzer and was found to be 85.1%. The natural content of the biofuel in the sample to be tested was calculated according to formula (4).

[0231]

[0232] Wherein, in formula (4): N represents the natural content of the sample; D BFTwo tubes of biofuel meet the count; D FF is the coincidence count of the two tubes of fossil fuel; E is the counting efficiency; T is the measurement time; m is the mass of the added aviation fuel sample; ω is the carbon content of the sample. According to Formula 4, the naturalness of the aviation fuel in Example 3 is 99.9%.

[0233] The above description is only a preferred embodiment of the present application and is not intended to limit the present application. Any modifications, equivalent substitutions, etc. made within the spirit and principles of the present application shall be included in the protection scope of the present application.

Claims

1. A method for determining the naturalness of fuel based on three-tube and two-tube coincidence ratio, characterized in that: include: Preparation 14 C sample and blank sample, the prepared 14 C sample and blank sample were stored in dark place for 0.01-60 hours, then put into three-tube liquid scintillation counter for measurement. 14 The TDCR value of C and the counting efficiency are based on 14 The TDCR value of C and the counting efficiency are fitted with the relationship curve of the TDCR value relative to the counting efficiency, and the formula of the counting efficiency is obtained according to the relationship curve of the fitted TDCR value relative to the counting efficiency; Prepare the sample to be tested, add biofuel and scintillation fluid into the sample bottle to be tested; Prepare background samples, add mineral fuel and scintillation liquid into the background sample bottle, store the sample to be tested and the background sample in a dark place for 0.01-60 hours, and then put them into a three-tube liquid scintillation counter for measurement. Calculate the TDCR value of biofuel based on the measurement results. 14 C counting efficiency formula calculates the counting efficiency of biofuel; The carbon content in the biofuel sample is measured using an elemental analyzer, and the naturalness of the biofuel is calculated based on the carbon content in the biofuel sample.

2. The method for determining the naturalness of fuel based on the three-tube and two-tube coincidence ratio according to claim 1 is characterized in that: The formulation 14 C sample includes: adding scintillation fluid, background material, 14 C standard substance and different concentrations of quencher; And / or, preparing blank samples includes: adding scintillation fluid, background material and quencher of different concentrations into blank sample vials.

3. The method for determining the naturalness of fuel oil based on the three-tube and two-tube coincidence ratio according to claim 2 is characterized in that: Said 14 C sample 14 The concentration of C standard substance is 300-5000 Bg / g; and / or, 14 C sample 14 The activity of the C standard substance is greater than 0.1 Bq; and / or, 14 The measurement time of C sample is 2-10 minutes.

4. The method for determining the naturalness of fuel oil based on the three-tube and two-tube coincidence ratio according to claim 2 is characterized in that: The background material is one of mineral oil and hexadecane.

5. The method for determining the naturalness of fuel based on the three-tube and two-tube coincidence ratio according to claim 2 is characterized in that: The quencher is any one of dye, nitromethane and carbon black. 14 The concentration of the quencher in the C sample or the blank sample is 0, 0.01%, 0.05%, 0.1%, 0.2%; preferably, the dye comprises a yellow pigment.

6. The method for determining the naturalness of fuel oil based on the three-tube and two-tube coincidence ratio according to claim 1 is characterized in that: The calculation based on the measurement results 14 The TDCR value of C includes: Calculated according to formula (1) 14 TDCR value of C Among them, in formula (1): T stands for 14 The three tubes of sample C meet the count; T B The three tubes representing the blank sample coincide with the count; D stands for 14 The two tubes of sample C meet the counts; D B The two tubes representing blank samples matched the counts.

7. The method for determining the naturalness of fuel oil based on the three-tube and two-tube coincidence ratio according to claim 1 is characterized in that: The calculation based on the measurement results 14 The counting efficiency of C includes: Calculate the counting efficiency according to formula (2): Among them, in formula (2): E stands for 14 C The counting efficiency of the sample; D stands for 14 The two tubes of sample C met the counts; D B The two tubes representing the blank sample conform to the count; A means 14 C The activity of the sample; T stands for 14 C The measurement duration of the sample.

8. The method for determining the naturalness of fuel oil based on the three-tube and two-tube coincidence ratio according to claim 1 is characterized in that: The volume ratio of the biofuel and the scintillation fluid added is 1-(0.5:1).

9. The method for determining the naturalness of fuel oil based on the three-tube and two-tube coincidence ratio according to claim 8 is characterized in that: The step of calculating the TDCR value of the biofuel according to the measurement results includes: calculating the TDCR value of the biofuel according to formula (3): Among them, in formula (3): T BF Three tubes of biofuels are counted; T FF Three tubes for fossil fuels meet the count; D BF Two tubes of biofuel meet the count, D FF Two tubes for fossil fuels meet the count.

10. The method for determining the naturalness of fuel oil based on the three-tube and two-tube coincidence ratio according to claim 8, characterized in that: The natural content of the biofuel sample is calculated according to the measurement results. Among them, in formula (4): N represents the natural content of the sample; D BF Two tubes of biofuel meet the count; D FF Two tubes for fossil fuels meet the count; E is the counting efficiency; T is the measurement time; m represents the mass of the added aviation fuel sample; ω represents the carbon content of the sample.

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