A method for liquid fuel bio-based attribute authentication based on liquid scintillation counter

Abstract

This invention discloses a method for identifying the bio-based properties of liquid fuels based on a liquid scintillation counter. 14 C isotope analysis is used to determine the bio-based content of liquid fuels, thereby identifying whether the liquid fuel is bio-based, fossil-based, or a mixture of bio-based and fossil-based. The steps include: S1, optimizing the experimental parameters of the liquid scintillation counter; S2, determining the sample counting efficiency; S3, determining the background sample... 14 β decay count of C; S4, calculate the bio-based content of the sample using a combination formula.

Description

Technical Field

[0001] This invention relates to the technical field of biofuel detection, and in particular to a method for identifying the bio-based properties of liquid fuels based on a liquid scintillation counter. Background Technology

[0002] Biodiesel, bio-aviation kerosene, and other novel bio-liquid fuels offer advantages such as low carbon emissions and renewability. With the introduction of the "dual carbon" target (referring to carbon emissions control and carbon sequestration), the potential market demand for bio-liquid fuels both domestically and internationally is vast. However, because these novel bio-liquid fuels share similar performance indicators with traditional petroleum-based fossil fuels (such as automotive diesel and No. 3 jet fuel), their biological properties cannot be effectively identified solely based on their physicochemical properties (such as distillation range, density, and calorific value).

[0003] Bio-based content is a core indicator for the certification of bio-based materials and an important reflection of their green attributes. Currently, carbon-14 (… 14 C) Isotope analysis is widely considered the internationally accepted method for determining bio-based content. Currently, international methods for determining... 14 The main methods for C include accelerator mass spectrometry and liquid scintillation counter method. However, the accelerator mass spectrometer used in accelerator mass spectrometry is expensive (approximately 20 million yuan per unit) and requires a dedicated space (approximately 100m²). 2 The preprocessing is complex and the testing cycle is long. Summary of the Invention

[0004] The main technical problem solved by this invention is to provide a method for identifying the bio-based properties of liquid fuels based on a liquid scintillation counter. This method utilizes a liquid scintillation counter... 14 C isotope analysis is used to determine the bio-based content of liquid fuels, thereby identifying whether the liquid fuel is bio-based, fossil-based, or a mixture of both. The liquid scintillation counter used is inexpensive, highly efficient, and accurate.

[0005] To solve the above-mentioned technical problems, one technical solution adopted by the present invention is: to provide a method for identifying the bio-based properties of liquid fuels based on a liquid scintillation counter, comprising the following steps:

[0006] S1. Optimize the experimental parameters and conditions of the liquid scintillation counter;

[0007] S2. Determine the sample counting efficiency: Add a trace amount of... to sample bottle a 14 A standard solution (C) and a quantitative amount of scintillation solution are mixed to form solution A. Solution A is then placed in the dark for a certain period of time before measurement. 14 β decay count of C; add a quantitative amount of sample to solution A to form solution B, and measure again after storing solution B in the dark for a certain period of time. 14β decay count of C; a fixed amount of scintillation fluid is added to sample vial b, followed by a fixed amount of sample, and the mixture is stirred to form solution C. Solution C is then stored in the dark for a certain period of time before the concentration of β decay in the sample is measured. 14 The β decay count of C; the sample counting efficiency C is calculated using a formula. e ;

[0008] S3. Determine the background sample. 14 β decay counting of C: A fixed amount of scintillation fluid is added to sample vial c, followed by a fixed amount of background sample, and the mixture is stirred to form solution D. Solution D is then stored in the dark for a certain period of time before the β decay count of the background sample is measured. 14 β decay count of C;

[0009] S4. The bio-based content of the sample is calculated using a combination formula.

[0010] In a specific embodiment of the present invention, the parameter conditions in S1 include: counting window, sample to scintillation fluid ratio, sample and scintillation fluid mixing time in the dark, and counting time.

[0011] In a specific embodiment of the present invention, the counting window includes 0 keV to 156 keV, the sample to scintillation fluid ratio is 1:3 to 3:1, the sample and scintillation fluid are mixed and placed in the dark for ≥1 hour, and the counting time is ≥10 minutes.

[0012] In a specific embodiment of the present invention, in step 2, the sample bottle a is added with 14 The volume of the C standard solution is 10µL to 100µL. 14 The specific activity of standard solution C is approximately 200 Bq / g to 3000 Bq / g, and the scintillation liquid volume is 5 mL to 15 mL. Solution A is stored in the dark for ≥1 h, and the sample volume added to solution A is 5 mL to 15 mL. Solution B is stored in the dark for ≥1 h, and solution C is stored in the dark for ≥1 h. The error in the volume of scintillation liquid added to solutions A and C does not exceed 0.1 mL. The error in the volume of sample added to solutions B and C does not exceed 0.1 mL.

[0013] In a specific embodiment of the present invention, in step 2, the sample counting efficiency C is calculated using a liquid scintillation counter with two independent detectors. e The formula is:

[0014] ;

[0015] In the formula:

[0016] C e For sample counting efficiency;

[0017] CPM SSFor solution B, the number of double coincidences per minute;

[0018] CPM S For solution C, the number of double coincidences per minute;

[0019] CPM SC Let A be the number of double coincidences per minute for solution A.

[0020] In a specific embodiment of the present invention, in step 2, the sample counting efficiency C is calculated using a liquid scintillation counter with three independent detectors. e The formula is:

[0021] ;

[0022] In the formula:

[0023] C e For sample counting efficiency;

[0024] CPM SS The triple coincidence count per minute for solution B;

[0025] CPM S The triple coincidence count per minute for solution C;

[0026] CPM SC The triple coincidence count per minute for solution A;

[0027] TDCR is the ratio of triple coincidence count to double coincidence count. TDCR can be calculated manually or automatically by a liquid scintillation counter.

[0028] In a specific embodiment of the present invention, in step 3, the volume of scintillation liquid added to sample bottle c is 5 mL to 15 mL, the volume of background sample added is 5 mL to 15 mL, the volume error of scintillation liquid added to solution C and solution D is no more than 0.1 mL, the volume error of sample added to solution C and solution D is no more than 0.1 mL, and the light-protected storage time of solution D is ≥1 h.

[0029] In a specific embodiment of the present invention, in steps 2 and 3, solutions A, B, C, and D can be placed in a liquid scintillation counter and kept in the dark for a certain period of time before measurement. 14 The β decay count of C can be performed, or solutions A, B, C, and D can be placed in a liquid scintillation counter after being protected from light for a certain period of time. 14 β decay count of C.

[0030] In a specific embodiment of the present invention, in step 3, the background sample is a fossil-based liquid paraffin, diesel, kerosene, or No. 3 jet fuel.

[0031] In a specific embodiment of the present invention, the combined formula for calculating the bio-based content of the sample in step 4 is as follows:

[0032]

[0033]

[0034]

[0035]

[0036] In the formula:

[0037] ω BC The percentage of bio-based carbon content in the sample, expressed as % (%).

[0038] DPM S For each gram of carbon in the sample 14 C decays per minute;

[0039] REF is the atmospheric correction factor. REF is the value of the year in which the sample was tested. The REF value in 2026 is 99.1. The latest REF value can be found in the current valid version of ASTM D6866. When the latest REF value is not available, the REF value of the year closest to the sample test is used.

[0040] CPM S For the sample (i.e., solution C), the coincidence count per minute (triple or double);

[0041] C S The carbon mass of the sample;

[0042] CPM B For the background sample (i.e., solution D), the coincidence count per minute (triple or double);

[0043] C B The carbon mass of the background sample;

[0044] C e For sample counting efficiency;

[0045] m S For sample quality;

[0046] C STC This represents the carbon content of the sample, which can be determined using standard methods (such as NB / SH / T 0656) or theoretical values. For kerosene or diesel-based samples, the theoretical value is 0.85; for naphtha-based samples, the theoretical value is 0.84.

[0047] m B This is the baseline sample quality;

[0048] C BTC This represents the carbon content of the background sample, which can be determined using standard methods (such as NB / SH / T 0656) or theoretical values. For background samples with kerosene or diesel base, the theoretical value is 0.85; for background samples with naphtha base, the theoretical value is 0.84. Detailed Implementation

[0049] The technical solutions in the embodiments of the present invention will be clearly and completely described below. Obviously, the described embodiments are only a part of the embodiments of the present invention, and not all of them. Based on the embodiments of the present invention, all other embodiments obtained by those skilled in the art without creative effort are within the scope of protection of the present invention.

[0050] Example 1

[0051] Method for identifying the bio-based properties of a certain hydrocarbon-based biodiesel:

[0052] S1. Optimize the experimental parameters of the liquid scintillation counter, which is equipped with two independent detectors. The optimized experimental parameters are: counting window of 4keV to 156keV, sample to scintillation liquid ratio of 1:1, sample and scintillation liquid mixed and placed in the dark for 4 hours, and counting time of 30 minutes.

[0053] S2. Determine the sample counting efficiency: Add 50µL of [unspecified substance] to sample vial a. 14 Solution A is prepared by mixing standard solution C (specific activity approximately 500 Bq / g) and 10 mL of scintillation fluid. Solution A is placed in a liquid scintillation counter and kept in the dark for 1 hour before measurement. 14 The β decay count of C was 1399. 10 mL of the hydrocarbon-based biodiesel sample was added to solution A to form solution B. Solution B was placed in a liquid scintillation counter and kept in the dark for 4 hours before being measured again. 14 The β decay count of C is 1350. 10 mL of scintillation fluid was first added to sample vial b, followed by 10 mL of the hydrocarbon-based biodiesel sample, mixing to form solution C. Solution C was placed in a liquid scintillation counter and kept in the dark for 4 hours before measurement. 14 The β decay count of C is 82.9. Calculate the counting efficiency C of this hydrocarbon-based biodiesel sample using the following formula. e :

[0054]

[0055] In the formula:

[0056] C e For sample counting efficiency;

[0057] CPMSS For solution B, the number of double coincidences per minute;

[0058] CPM S For solution C, the number of double coincidences per minute;

[0059] CPM SC Let A be the number of double coincidences per minute for solution A.

[0060] The counting efficiency of the hydrocarbon-based biodiesel sample was calculated to be 0.91.

[0061] S3. Determine the background sample. 14 β decay count of C: Add 10 mL of scintillation fluid to sample vial c, then add 10 mL of background sample to form solution D. Place solution D in a liquid scintillation counter and store in the dark for 4 hours before measuring. 14 The β decay count of C is 0.8, where the background sample is fossil-based diesel.

[0062] S4. The bio-based content of the sample is calculated using a combination formula, which is:

[0063]

[0064]

[0065]

[0066]

[0067] In the formula:

[0068] ω BC The percentage of bio-based carbon content in the sample, expressed as % (%).

[0069] DPM S For each gram of carbon in the sample 14 C decays per minute;

[0070] REF stands for atmospheric correction factor;

[0071] CPM S For the sample (i.e., solution C), the double coincidence count per minute;

[0072] C S The carbon mass of the sample;

[0073] CPM B The double coincidence count per minute for the background sample (i.e., solution D);

[0074] C B The carbon mass of the background sample;

[0075] C e For sample counting efficiency;

[0076] m S For sample quality;

[0077] C STC The carbon content of the sample;

[0078] m B This is the baseline sample quality;

[0079] C BTC This represents the carbon content of the background sample.

[0080] The mass of the hydrocarbon-based biodiesel sample was 7.8462 g, and the carbon content was 0.85%. The mass of the background sample was 7.8776 g, and the carbon content was also 0.85. Taking the REF value as 99.1, the calculated bio-based carbon content of the sample was 100.7%. Considering the precision of this method, this hydrocarbon-based biodiesel is indeed bio-based.

[0081] Example 2

[0082] A method for identifying the bio-based properties of a certain bio-aviation kerosene includes the following steps:

[0083] S1. Optimize the experimental parameters of the liquid scintillation counter, which is equipped with three independent detectors. The parameters include: counting window, sample-to-scintillation fluid ratio, light-protected time after mixing the sample and scintillation fluid, and counting time. The optimized counting window is 0 keV to 156 keV, the sample-to-scintillation fluid ratio is 3:1, the light-protected time after mixing the sample and scintillation fluid is 8 hours, and the counting time is 60 minutes.

[0084] S2. Determine the sample counting efficiency: Add 20µL of [unspecified substance] to sample vial a. 14 Solution A is prepared by mixing standard solution C (specific activity approximately 2000 Bq / g) and 5 mL of scintillation fluid. Solution A is then placed in the dark and protected from light for 8 hours before being measured using a liquid scintillation counter. 14 The β decay count of C is 1566.5; 15 mL of sample was added to solution A to form solution B. Solution B was placed in the dark for 8 hours and then measured using a liquid scintillation counter. 14 The β decay count of C was 1450.2, and the TDCR calculated by the liquid scintillation counter was 0.96. 5 mL of scintillation fluid was added to sample vial b, followed by 15 mL of the bio-aviation kerosene sample, mixing to form solution C. Solution C was placed in the dark for 8 hours before being measured using the liquid scintillation counter. 14 The β decay count of C is 56.6. The sample counting efficiency C was calculated using a liquid scintillation counter with three independent detectors. eThe formula is:

[0085]

[0086] In the formula:

[0087] C e For sample counting efficiency;

[0088] CPM SS The triple coincidence count per minute for solution B;

[0089] CPM S The triple coincidence count per minute for solution C;

[0090] CPM SC The triple coincidence count per minute for solution A;

[0091] TDCR is the ratio of triple coincidence count to double coincidence count.

[0092] The counting efficiency of the bio-aviation kerosene sample was calculated to be 0.85.

[0093] S3. Determine the background sample. 14 β decay count of C: Add 5 mL of scintillation fluid to sample vial c, then add 15 mL of background sample to form solution D. Place solution D in the dark for 8 hours and then measure it in a liquid scintillation counter. 14 The β decay count of C is 5.0, of which the background sample is fossil-based liquid paraffin;

[0094] S4. The bio-based content of the sample is calculated using a combination formula, which is:

[0095]

[0096]

[0097]

[0098]

[0099] In the formula:

[0100] ω BC The percentage of bio-based carbon content in the sample, expressed as % (%).

[0101] DPM S For each gram of carbon in the sample 14 C decays per minute;

[0102] REF stands for atmospheric correction factor;

[0103] CPM SThe triple coincidence count per minute for the sample (i.e., solution C);

[0104] C S The carbon mass of the sample;

[0105] CPM B The triple coincidence count per minute for the background sample (i.e., solution D);

[0106] C B The carbon mass of the background sample;

[0107] C e For sample counting efficiency;

[0108] m S For sample quality;

[0109] C STC The carbon content of the sample;

[0110] m B This is the baseline sample quality;

[0111] C BTC This represents the carbon content of the background sample.

[0112] The sample weighed 7.6677 g with a carbon content of 0.85%. The background sample weighed 8.2835 g with a carbon content of 0.85. The REF value was 99.1. Calculations showed that the bio-based carbon content of the sample was 69.8%. Considering the precision of this method, this bio-aviation kerosene is a mixture of bio-based and fossil-based components.

[0113] The beneficial effects of this invention: utilizing a liquid scintillation counter... 14 C isotope analysis technology is used to determine the bio-based content of liquid fuels, thereby identifying whether the liquid fuel is bio-based or fossil-based. The liquid scintillation counter used is relatively inexpensive (about 1.5 million), has high testing efficiency (20 samples can be tested within 24 hours), and high accuracy (the intra-laboratory repeatability limit is 3.3%, and the inter-laboratory reproducibility limit is 4.0%).

[0114] The above description is merely an embodiment of the present invention and does not limit the patent scope of the present invention. Any equivalent structural or procedural transformations made based on the content of the present invention specification, or direct or indirect applications in other related technical fields, are similarly included within the patent protection scope of the present invention.

Claims

1. A method for identifying the bio-based properties of liquid fuels based on a liquid scintillation counter, characterized in that, Includes the following steps: S1. Optimize the experimental parameters and conditions of the liquid scintillation counter; S2. Determine the sample counting efficiency: Add a trace amount of... to sample bottle a 14 A standard solution (C) and a quantitative amount of scintillation solution are mixed to form solution A. Solution A is then placed in the dark for a certain period of time before measurement. 14 β decay count of C; add a quantitative amount of sample to solution A to form solution B, and measure again after storing solution B in the dark for a certain period of time. 14 β decay count of C; a fixed amount of scintillation fluid is added to sample vial b, followed by a fixed amount of sample, and the mixture is stirred to form solution C. Solution C is then stored in the dark for a certain period of time before the concentration of β decay in the sample is measured. 14 The β decay count of C; the sample counting efficiency C is calculated using a formula. e ; S3, Determine the background sample 14 β decay counting of C: A fixed amount of scintillation fluid is added to sample vial c, followed by a fixed amount of background sample, and the mixture is stirred to form solution D. Solution D is then stored in the dark for a certain period of time before the β decay count of the background sample is measured. 14 β decay count of C; S4. The bio-based content of the sample is calculated using a combination formula.

2. The method for identifying the bio-based properties of liquid fuels based on a liquid scintillation counter according to claim 1, characterized in that, In S1, the parameter conditions include: counting window, sample to scintillation fluid ratio, sample and scintillation fluid mixing time in the dark, and counting time.

3. The method for identifying the bio-based properties of liquid fuels based on a liquid scintillation counter according to claim 2, characterized in that, The counting window includes 0 keV to 156 keV, the sample to scintillation fluid ratio is 1:3 to 3:1, the sample and scintillation fluid are mixed and placed in the dark for ≥1 hour, and the counting time is ≥10 minutes.

4. The method for identifying the bio-based properties of liquid fuels based on a liquid scintillation counter according to claim 1, characterized in that, In step 2, the sample vial a is added with 14 The volume of the C standard solution is 10µL to 100µL. 14 The specific activity of standard solution C is approximately 200 Bq / g to 3000 Bq / g, and the scintillation liquid volume is 5 mL to 15 mL. Solution A is stored in the dark for ≥1 h, and the sample volume added to solution A is 5 mL to 15 mL. Solution B is stored in the dark for ≥1 h, and solution C is stored in the dark for ≥1 h. The error in the volume of scintillation liquid added to solutions A and C does not exceed 0.1 mL. The error in the volume of sample added to solutions B and C does not exceed 0.1 mL.

5. The method for identifying the bio-based properties of liquid fuels based on a liquid scintillation counter according to claim 1, characterized in that, In step 2, the sample counting efficiency C is calculated using a liquid scintillation counter with two independent detectors. e The formula is: ； In the formula: C e For sample counting efficiency; CPM SS For solution B, the number of double coincidences per minute; CPM S For solution C, the number of double coincidences per minute; CPM SC Let A be the number of double coincidences per minute for solution A.

6. The method for identifying the bio-based properties of liquid fuels based on a liquid scintillation counter according to claim 1, characterized in that, In step 2, the sample counting efficiency C is calculated using a liquid scintillation counter with three independent detectors. e The formula is: ； In the formula: C e For sample counting efficiency; CPM SS The triple coincidence count per minute for solution B; CPM S The triple coincidence count per minute for solution C; CPM SC The triple coincidence count per minute for solution A; TDCR is the ratio of triple coincidence count to double coincidence count.

7. The method for identifying the bio-based properties of liquid fuels based on a liquid scintillation counter according to claim 1, characterized in that, In step 3, the volume of scintillation liquid added to sample bottle c is 5 mL to 15 mL, the volume of background sample added is 5 mL to 15 mL, the volume error of scintillation liquid added to solution C and solution D is no more than 0.1 mL, the volume error of sample added to solution C and solution D is no more than 0.1 mL, and the light-protected storage time of solution D is ≥1 h.

8. The method for identifying the bio-based properties of liquid fuels based on a liquid scintillation counter according to claim 1, characterized in that, In steps 2 and 3, solutions A, B, C, and D can be placed in a liquid scintillation counter and kept in the dark for a certain period of time before measurement. 14 The β decay count of C can be performed, or solutions A, B, C, and D can be placed in a liquid scintillation counter after being protected from light for a certain period of time. 14 β decay count of C.

9. The method for identifying the bio-based properties of liquid fuels based on a liquid scintillation counter according to claim 1, characterized in that, In step 3, the background sample is a fossil-based liquid paraffin, diesel, kerosene, or No. 3 jet fuel.

10. The method for identifying the bio-based properties of liquid fuels based on a liquid scintillation counter according to claim 1, characterized in that, In step 4, the combined formula include: ; ； ； ； In the formula: ω BC The percentage of bio-based carbon content in the sample, expressed as % (%). DPM S For each gram of carbon in the sample 14 C decays per minute; REF is the atmospheric correction factor. REF is the value of the year in which the sample was tested. The REF value in 2026 is 99.

1. When the latest REF value is not available, the REF value of the year closest to the sample test is used. CPM S For the triple or double coincidence count of the sample per minute; C S The carbon mass of the sample; CPM B The triple or double coincidence count per minute for the background sample; C B The carbon mass of the background sample; C e For sample counting efficiency; m S For sample quality; C STC The carbon content of the sample; m B This is the baseline sample quality; C BTC This represents the carbon content of the background sample.

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