Analysis Method for Group Composition of Specific Fractions of Crude Oil

Abstract

The present invention relates to the technical field of crude oil analysis and is a method for analyzing the group composition of specific fractions of crude oil. The method is carried out according to the following steps: Weigh a crude oil sample, add n-alkanes for dissolution to obtain a crude oil sample solution; Use chromatography to separate the crude oil sample solution to obtain a saturated hydrocarbon component solution and an aromatic hydrocarbon component solution; In the third step, use GC / MS to respectively measure the saturated hydrocarbon components in the saturated hydrocarbon solution and the aromatic hydrocarbon components in the aromatic hydrocarbon solution to obtain the total ion current chromatograms of the saturated hydrocarbons and aromatic hydrocarbons respectively, analyze the total ion current chromatograms, and calculate the group composition of the specific fractions. The present invention can quickly realize the analysis of the group composition of specific fractions of crude oil. Compared with traditional crude oil evaluation, the amount of sample required for analysis is small, the analysis time is short, the analysis efficiency is high, and the results are accurate.

Description

Technical Field

[0001] The present invention relates to the technical field of crude oil analysis, and is a method for analyzing the group composition of specific fractions of crude oil. Background Art

[0002] The composition of crude oil is closely related to the physical properties and processability of crude oil. With the diversification and refinement of petroleum processing, on the basis of a comprehensive analysis of the physical properties of crude oil, the processability of crude oil and the selection of appropriate processing methods and product plans are carried out accordingly, so as to realize the rational utilization of crude oil. Therefore, it is very important to quickly characterize the composition of crude oil. However, due to the complex composition of crude oil, the detailed hydrocarbon composition of crude oil has not been rapidly analyzed yet.

[0003] Traditional crude oil evaluation is to first perform true boiling point distillation on crude oil, and then use corresponding methods to measure the composition of each fraction. The sample consumption of this method is 4L to 5L, and the analysis period is usually 1 to 2 weeks, which brings difficulties to understanding the properties of crude oil in a timely manner. At present, in the rapid evaluation of crude oil, there are mainly spectroscopic and spectrometric techniques such as near-infrared spectroscopy (NIR), mid-infrared spectroscopy (IR), and nuclear magnetic resonance spectroscopy (NMR). They mostly use chemometric methods to establish analysis models, but good application effects can only be obtained on the premise of ensuring a perfect database. Considerable manpower and material resources are required for early-stage modeling and later-stage data maintenance. Existing hydrocarbon composition methods such as ASTM D2789, ASTM D2425, ASTM D2786, ASTM D3239 and equivalent domestic standards only analyze gasoline, diesel, and gas oil fractions and cannot analyze crude oil. Liu Yingrong disclosed a method in the article "Rapid Determination of Detailed Hydrocarbon Composition of Fractions with Boiling Points Lower than 540 °C in Crude Oil by GC-MS" that directly measures crude oil samples using GC / MS technology, strips the spectrum into saturated hydrocarbon spectra and aromatic hydrocarbon spectra, and then uses a secondary correction method. However, the interactive effects of saturated hydrocarbons and aromatic hydrocarbons in the spectrum will cause analysis errors, and a high accuracy requirement for secondary correction is needed [Liu Yingrong, Rapid Determination of Detailed Hydrocarbon Composition of Fractions with Boiling Points Lower than 540 °C in Crude Oil by GC-MS. Petrochemical Technology. Vol. 44, No. 3, 2015].

[0004] At present, there is no relevant report on directly separating saturated hydrocarbon components and aromatic hydrocarbon components from crude oil, analyzing them separately by GC / MS, and obtaining group composition data of specific fractions. Summary of the Invention

[0005] The present invention provides a method for analyzing the group composition of specific fractions of crude oil, which overcomes the deficiencies of the above-mentioned prior art and can effectively solve the problems of cumbersome steps and low accuracy in the detection methods of saturated hydrocarbon components and aromatic hydrocarbon components in existing crude oil samples.

[0006] The technical solution of the present invention is achieved by the following measures: A method for analyzing the group composition of specific fractions of crude oil is carried out according to the following steps:

[0007] In the first step, 0.05 g to 0.30 g of crude oil sample is weighed and dissolved by adding 3 ml to 20 ml of n-alkane to obtain a crude oil sample solution.

[0008] In the second step, the crude oil sample solution is separated by chromatography to obtain a saturated hydrocarbon component solution and an aromatic hydrocarbon component solution. Among them, the adsorbent used in the chromatography is an activated solid oxide adsorbent. The length of the chromatography column is 250 mm to 750 mm, the diameter is 10 mm to 20 mm, and the amount of adsorbent used is 5 g to 30 g.

[0009] In the third step, GC / MS is used to measure the saturated hydrocarbon components in the saturated hydrocarbon solution and the aromatic hydrocarbon components in the aromatic hydrocarbon solution respectively, obtaining the total ion current chromatogram of the saturated hydrocarbons and the total ion current chromatogram of the aromatic hydrocarbons respectively. Analyze the total ion current chromatogram of the saturated hydrocarbons and the total ion current chromatogram of the aromatic hydrocarbons, and calculate the group composition of the specific fraction.

[0010] The following is a further optimization or / and improvement of one of the above-mentioned invention technical solutions:

[0011] In the above first step, the n-alkane is one of C5 to C7 n-alkanes.

[0012] In the above second step, the specific steps for separating the crude oil sample solution into a saturated hydrocarbon component solution and an aromatic hydrocarbon component solution by chromatography are as follows: Transfer the crude oil sample solution into the chromatography column. After the added sample solution disappears from the surface of the adsorbent, add 20 ml to 120 ml of n-alkane identical to the sample solvent for elution, with an elution rate of 1 ml / min to 3 ml / min. Collect the n-alkane eluate, concentrate and fix the volume to obtain the saturated hydrocarbon component solution. Then add 20 ml to 120 ml of a mixed solution of alcohol and chlorinated hydrocarbon solvent to the chromatography column for elution, with an elution rate of 1 ml / min to 3 ml / min. Collect the eluate of the mixed solution of alcohol and chlorinated hydrocarbon solvent, concentrate and fix the volume to obtain the aromatic hydrocarbon component solution.

[0013] In the above mixed solution of alcohol and chlorinated hydrocarbon solvent, the alcohol is one of C1 to C3 alcohols, the chlorinated hydrocarbon is dichloromethane or trichloromethane, and the volume ratio of alcohol to chlorinated hydrocarbon is 0:1 to 1:10.

[0014] The above solid oxide adsorbent is one of Fe2O3, Al2O3, MnO2 and SiO2, and the mesh size of the solid oxide adsorbent is 100 mesh to 300 mesh.

[0015] In the second step above, the activation process is to heat the solid oxide adsorbent at 400°C to 550°C for 1 h to 5 h. After cooling to room temperature, distilled water with a mass ratio of 0.5% to 5% is added, and it is left for 12 h to 48 h for standby.

[0016] In the third step above, the GC / MS chromatographic conditions are as follows: the chromatographic column is a non-polar chromatographic column or a weakly polar chromatographic column, with a column length of 30 m to 60 m and a diameter of 0.25 mm to 0.5 mm. The inlet temperature is 280°C to 300°C, the carrier gas is helium, the split injection split ratio is 10:1 to 100:1, and the temperature programming is to start at 35°C to 50°C, rise to 300°C, and hold until all components flow out.

[0017] In the third step above, the GC / MS mass spectrometric conditions are as follows: the GC / MS interface temperature is 280°C to 300°C, the mass spectrometry scanning range is 30 amu to 500 amu, the electron impact ionization energy is 70 eV to 90 eV, the EI ion source temperature is 200°C to 230°C, and the acquisition mode is full scan.

[0018] In the third step above, the calculation is to select the carbon number distribution range of the chromatographic peaks of specific fractions in the GC / MS chromatogram, calculate the sum of the characteristic mass fragments of various hydrocarbons through the GC / MS workstation, and use the group composition working software that meets the requirements of ASTM D2425 or ASTM D3239 methods for analysis and calculation to obtain the group composition.

[0019] The specific fraction of the above crude oil is the crude oil fraction with a carbon number range of C10 to C32.

[0020] The present invention provides a method for analyzing the group composition of specific fractions of crude oil. This method uses chromatographic separation technology to separate the crude oil sample, and the separated saturated hydrocarbons and aromatics are determined by GC / MS. Quantitative analysis of the group composition is achieved through analysis and calculation by selecting the carbon number distribution range of specific fractions. This method can quickly analyze the group composition of specific fractions of crude oil. Compared with traditional crude oil evaluation, it requires less sample volume, shorter analysis time, higher analysis efficiency, and accurate results. Detailed implementation mode

[0021] The present invention is not limited by the following embodiments, and the specific implementation mode can be determined according to the technical solution of the present invention and the actual situation. Various chemical reagents and chemical supplies mentioned in the present invention are all well-known and commonly used chemical reagents and chemical supplies in the prior art unless otherwise specified; the normal temperature and room temperature in the present invention generally refer to the temperature of 15°C to 25°C, and are generally defined as 25°C.

[0022] The following further describes the present invention in conjunction with embodiments:

[0023] Example 1: The method for analyzing the group composition of a specific fraction of crude oil is carried out according to the following steps:

[0024] In the first step, 0.05 g to 0.30 g of the crude oil sample is weighed and dissolved by adding 3 ml to 20 ml of n-alkanes to obtain a crude oil sample solution.

[0025] In the second step, the crude oil sample solution is separated by chromatography to obtain a saturated hydrocarbon component solution and an aromatic hydrocarbon component solution. Among them, the adsorbent used in the chromatography is an activated solid oxide adsorbent. The length of the chromatography column is 250 mm to 750 mm, the diameter is 10 mm to 20 mm, and the amount of adsorbent used is 5 g to 30 g.

[0026] In the third step, GC / MS is used to measure the saturated hydrocarbon components in the saturated hydrocarbon solution and the aromatic hydrocarbon components in the aromatic hydrocarbon solution respectively, obtaining the total ion current chromatogram of the saturated hydrocarbons and the total ion current chromatogram of the aromatic hydrocarbons respectively. The total ion current chromatograms of the saturated hydrocarbons and the aromatic hydrocarbons are analyzed to calculate the group composition of the specific fraction.

[0027] The present invention quantitatively analyzes the group composition of characteristic fractions in crude oil. The crude oil is directly separated by a chromatography column to obtain saturated hydrocarbons and aromatic hydrocarbons, and the group composition data of specific fractions is obtained through GC / MS analysis, with relatively high analysis efficiency. The quantitatively analyzed group composition of specific fractions can be used to correlate the physical properties of fractionated oils and evaluate the influence of compositional changes on product performance. Compared with traditional crude oil evaluation, the operation steps are greatly simplified, and rapid evaluation of crude oil can be achieved.

[0028] Example 2: As an optimization of the above example, in the first step, the n-alkane is one of C5 to C7 n-alkanes.

[0029] Example 3: As an optimization of the above example, in the second step, the specific steps for separating the crude oil sample solution into a saturated hydrocarbon component solution and an aromatic hydrocarbon component solution by chromatography are as follows: The crude oil sample solution is transferred into the chromatography column. After the added sample solution disappears from the surface of the adsorbent, 20 ml to 120 ml of n-alkanes identical to the sample solvent are added for elution, and the elution rate is 1 ml / min to 3 ml / min. The n-alkane eluate is collected, concentrated and fixed in volume to obtain a saturated hydrocarbon component solution. Then, 20 ml to 120 ml of a mixed solution of alcohol and chlorinated hydrocarbon solvent is added to the chromatography column for elution, and the elution rate is 1 ml / min to 3 ml / min. The eluate of the mixed solution of alcohol and chlorinated hydrocarbon solvent is collected, concentrated and fixed in volume to obtain an aromatic hydrocarbon component solution.

[0030] In the present invention, the collected n-alkane eluate and the eluate of the mixed solution of alcohol and chlorinated hydrocarbon solvent are both concentrated to less than 1 ml by a rotary evaporator. The operating conditions of the rotary evaporation are a rotation speed of 100 rpm to 120 rpm and a temperature less than or equal to 70°C. During concentration, the pressure is first set to 450 mmHg to evaporate the solvent, and then the pressure is reduced to completely evaporate the solvent. After that, the concentrated eluate of the saturated hydrocarbon component and the eluate of the aromatic hydrocarbon component are respectively transferred to a 1-ml volumetric flask and made up to 1 ml with n-hexane to obtain the saturated hydrocarbon component solution and the aromatic hydrocarbon component solution.

[0031] Example 4: As an optimization of the above example, in the mixed solution of alcohol and chlorinated hydrocarbon solvent, the alcohol is one of C1 to C3 alcohols, the chlorinated hydrocarbon is dichloromethane or trichloromethane, and the volume ratio of alcohol to chlorinated hydrocarbon is 0:1 to 1:10.

[0032] Example 5: As an optimization of the above example, the solid oxide adsorbent is one of Fe2O3, Al2O3, MnO2, and SiO2, and the particle size of the solid oxide adsorbent is 100 mesh to 300 mesh.

[0033] Example 6: As an optimization of the above example, in the second step, the activation process is to heat the solid oxide adsorbent at 400°C to 550°C for 1 h to 5 h, add distilled water with a mass ratio of 0.5% to 5% after cooling to room temperature, and let it stand for 12 h to 48 h for standby.

[0034] Example 7: As an optimization of the above example, in the third step, the GC / MS chromatographic conditions are as follows: the chromatographic column is a non-polar chromatographic column or a weakly polar chromatographic column, the column length is 30 m to 60 m, the diameter is 0.25 mm to 0.5 mm, the inlet temperature is 280°C to 300°C, the carrier gas is helium, the split injection split ratio is 10:1 to 100:1, and the temperature programming is to start at 35°C to 50°C, rise to 300°C, and hold until all components flow out.

[0035] Example 8: As an optimization of the above example, in the third step, the GC / MS mass spectrometry conditions are as follows: the GC / MS interface temperature is 280°C to 300°C, the mass spectrometry scanning range is 30 amu to 500 amu, the electron impact ionization energy is 70 eV to 90 eV, the EI ion source temperature is 200°C to 230°C, and the acquisition mode is full scan.

[0036] Example 9: As an optimization of the above example, in the third step, the calculation is to select the carbon number distribution range of specific fraction chromatographic peaks in the GC / MS chromatogram, calculate the sum of characteristic mass fragments of various hydrocarbons through the GC / MS workstation, and use the group composition working software that meets the requirements of ASTM D2425 or ASTM D3239 methods for analysis and calculation to obtain the group composition.

[0037] Example 10: In the above examples, the specific fraction of crude oil is a crude oil fraction with a carbon number range from C10 to C32.

[0038] In the present invention, the crude oil can be paraffinic base, intermediate base, naphthenic base crude oil, etc.; the fraction of the crude oil sample can be a specific fraction such as a diesel fraction or a lubricating oil fraction, or can also be the first key fraction and the second key fraction for crude oil classification.

[0039] Example 11: Weigh 0.100 g of paraffinic base crude oil sample and add 10 ml of n - hexane to dissolve it evenly. Using chromatography technology, SiO2 with a mesh size of 100 to 200 meshes is activated at 400 °C for 1 hour, and after adding 1% distilled water and standing for 24 hours, it is added to a chromatographic column with a diameter of 10 mm and a column length of 300 mm. The adsorbent dosage is 10 g. Using 30 ml of n - heptane as the mobile phase, the saturated hydrocarbon fraction is obtained by rinsing. Then, it is rinsed with 40 ml of dichloromethane + 5% anhydrous ethanol to obtain the aromatic hydrocarbon fraction, and the rinsing speed is 2 ml / min. The collected saturated hydrocarbon fraction and aromatic hydrocarbon fraction are concentrated by rotary evaporation at a rotation speed of 120 rpm and a temperature of 50 °C. First, the pressure is set to 450 mmHg to evaporate the solvent, and then the pressure is reduced to completely evaporate the solvent, and it is made up to 1 ml with n - hexane.

[0040] GC / MS is used to measure the saturated hydrocarbon and aromatic hydrocarbon fractions respectively to obtain the full - scan ion current chromatogram. Chromatographic conditions: Use a non - polar 30 m×0.25 mm×0.1 μm chromatographic column; the inlet temperature is 280 °C; the carrier gas is helium; split injection is carried out according to a split ratio of 100:1; the temperature - rising program: starting from 50 °C, it is raised to 300 °C and maintained until all components flow out. Mass spectrometry conditions: The GC / MS interface temperature is 280 °C; the mass spectrometry scanning range is 30 amu to 500 amu; the electron impact ionization energy is 70 eV; the EI ion source temperature is 230 °C; the acquisition mode is full - scan.

[0041] Gas chromatography is used to determine the carbon number distribution range of transformer oil from C15 to C21. Select this section of the carbon number distribution range in the chromatographic peaks of the crude oil, extract the transformer oil fractions in the saturated hydrocarbon and aromatic hydrocarbon, calculate the sum of the characteristic mass fragments of various hydrocarbons using the GC / MS working software, and use the group composition working software to calculate the group composition. The results are shown in Table 1.

[0042] Example 12: Weigh 0.100 g of paraffin-based crude oil sample and add 10 ml of n-hexane to dissolve it evenly. Using chromatography technology, Fe2O3 with a mesh size of 100 to 200 is activated at 400 °C for 1 hour. After adding 1% distilled water and standing for 24 hours, it is added to a chromatographic column with a diameter of 10 mm and a column length of 300 mm. The adsorbent dosage is 10 g. Using 30 ml of n-heptane as the mobile phase, the saturated hydrocarbon fraction is obtained by rinsing. Using 40 ml of dichloromethane + 5% anhydrous ethanol for rinsing, the aromatic hydrocarbon fraction is obtained, and the rinsing speed is 2 ml / min. The collected saturated hydrocarbon fraction and aromatic hydrocarbon fraction are concentrated by rotary evaporation at a rotation speed of 120 rpm and a temperature of 50 °C. First, the pressure is set to 450 mmHg to evaporate the solvent, and then the pressure is reduced to completely evaporate the solvent, and the volume is fixed to 1 ml with n-hexane.

[0043] The saturated hydrocarbon and aromatic hydrocarbon fractions are respectively measured by GC / MS to obtain the total scan ion current chromatogram. Chromatographic conditions: Use a non-polar 30 m × 0.25 mm × 0.1 μm chromatographic column; the injection port temperature is 280 °C; the carrier gas is helium; split injection is carried out according to a split ratio of 100:1; temperature programming: starting from 50 °C and rising to 300 °C, and maintaining until all components flow out. Mass spectrometry conditions: The GC / MS interface temperature is 280 °C; the mass spectrometry scanning range is 30 amu to 500 amu; the electron impact ionization energy is 70 eV; the EI ion source temperature is 230 °C; the acquisition method is total scan.

[0044] The carbon number distribution range of transformer oil C15 to C21 is determined by gas chromatography. Select this carbon number distribution range in the crude oil chromatographic peak, extract the transformer oil fraction in the saturated hydrocarbon and aromatic hydrocarbon, calculate the sum of the characteristic mass fragments of various hydrocarbons using the GC / MS working software, and calculate the group composition using the group composition working software. The results are shown in Table 1.

[0045] Example 13: Weigh 0.100 g of paraffin-based crude oil sample and add 10 ml of n-hexane to dissolve it evenly. Using chromatography technology, MnO2 with a mesh size of 100 to 200 is activated at 400 °C for 1 hour. After adding 1% distilled water and standing for 24 hours, it is added to a chromatographic column with a diameter of 10 mm and a column length of 300 mm. The adsorbent dosage is 10 g. Using 30 ml of n-heptane as the mobile phase, the saturated hydrocarbon fraction is obtained by rinsing. Using 40 ml of dichloromethane + 5% anhydrous ethanol for rinsing, the aromatic hydrocarbon fraction is obtained, and the rinsing speed is 2 ml / min. The collected saturated hydrocarbon fraction and aromatic hydrocarbon fraction are concentrated by rotary evaporation at a rotation speed of 120 rpm and a temperature of 50 °C. First, the pressure is set to 450 mmHg to evaporate the solvent, and then the pressure is reduced to completely evaporate the solvent, and the volume is fixed to 1 ml with n-hexane.

[0046] The saturated hydrocarbon and aromatic hydrocarbon components were measured by GC / MS respectively to obtain the total scan ion current chromatogram. Chromatographic conditions: a non-polar chromatographic column of 30m×0.25mm×0.1μm was used; the inlet temperature was 280°C; the carrier gas was helium; split injection was carried out according to a split ratio of 100:1; temperature programming: starting from 50°C and rising to 300°C, and holding until all components flowed out. Mass spectrometry conditions: the GC / MS interface temperature was 280°C; the mass spectrometry scanning range was from 30amu to 500amu; the electron impact ionization energy was 70eV; the EI ion source temperature was 230°C; the acquisition mode was total scan.

[0047] Gas chromatography was used to determine the carbon number distribution range of C15 to C21 in transformer oil. The carbon number distribution range in the crude oil chromatographic peak was selected, the transformer oil fractions in the saturated hydrocarbon and aromatic hydrocarbon were extracted, the sum of the characteristic mass fragments of various hydrocarbons was calculated using the GC / MS working software, and the group composition was calculated using the group composition working software. The results are shown in Table 1.

[0048] Example 14: Weigh 0.050g of paraffin-based crude oil sample and add 3ml of n-pentane to dissolve it evenly. Using chromatography technology, Al2O3 with a mesh size of 200 to 300 was activated at 550°C for 1 hour, and after adding 5% distilled water and leaving it for 48 hours, it was added to a chromatographic column with a diameter of 10mm and a column length of 300mm. The adsorbent dosage was 10g, and 30ml of n-heptane was used as the mobile phase to wash to obtain the saturated hydrocarbon component. Then, it was washed with 40ml of dichloromethane + 5% anhydrous ethanol to obtain the aromatic hydrocarbon component, and the washing speed was 1ml / min. The collected saturated hydrocarbon component and aromatic hydrocarbon component were concentrated by rotary evaporation at a rotation speed of 120rpm and a temperature of 50°C. First, the pressure was set to 450mmHg to evaporate the solvent, and then the pressure was reduced to completely evaporate the solvent, and the volume was fixed to 1ml with n-hexane.

[0049] The saturated hydrocarbon and aromatic hydrocarbon components were measured by GC / MS respectively to obtain the total scan ion current chromatogram. Chromatographic conditions: a non-polar chromatographic column of 30m×0.25mm×0.1μm was used; the inlet temperature was 280°C; the carrier gas was helium; split injection was carried out according to a split ratio of 100:1; temperature programming: starting from 50°C and rising to 300°C, and holding until all components flowed out. Mass spectrometry conditions: the GC / MS interface temperature was 280°C; the mass spectrometry scanning range was from 30amu to 500amu; the electron impact ionization energy was 70eV; the EI ion source temperature was 230°C; the acquisition mode was total scan.

[0050] Gas chromatography was used to determine the carbon number distribution range of C15 to C21 in transformer oil. The carbon number distribution range in the crude oil chromatographic peak was selected, the transformer oil fractions in the saturated hydrocarbon and aromatic hydrocarbon were extracted, the sum of the characteristic mass fragments of various hydrocarbons was calculated using the GC / MS working software, and the group composition was calculated using the group composition working software. The results are shown in Table 1.

[0051] Example 15: Weigh 0.100 g of paraffin-based crude oil sample and add 10 ml of n-heptane to dissolve it evenly. Using chromatography technology, Al2O3 with a particle size of 100 to 200 meshes is activated at 550 °C for 2 hours. After adding 1% distilled water and leaving it for 24 hours, it is added to a chromatographic column with a diameter of 20 mm and a column length of 100 mm. The adsorbent dosage is 5 g. Using 30 ml of n-heptane as the mobile phase, the saturated hydrocarbon fraction is obtained by rinsing. Then, 40 ml of dichloromethane + 5% anhydrous ethanol is used for rinsing to obtain the aromatic hydrocarbon fraction, and the rinsing speed is 3 ml / min. The collected saturated hydrocarbon fraction and aromatic hydrocarbon fraction are concentrated by rotary evaporation at a rotation speed of 120 rpm and a temperature of 50 °C. First, the pressure is set to 450 mmHg to evaporate the solvent, and then the pressure is reduced to completely evaporate the solvent. The volume is fixed to 1 ml with n-hexane.

[0052] The saturated hydrocarbon and aromatic hydrocarbon fractions are respectively measured by GC / MS to obtain the full-scan ion current chromatogram. Chromatographic conditions: Use a non-polar 30 m × 0.25 mm × 0.1 μm chromatographic column; the inlet temperature is 280 °C; the carrier gas is helium; split injection is carried out according to a split ratio of 100:1; temperature programming: starting from 50 °C, it is raised to 300 °C and held until all components flow out. Mass spectrometry conditions: The GC / MS interface temperature is 280 °C; the mass spectrometry scanning range is 30 amu to 500 amu; the electron impact ionization energy is 70 eV; the EI ion source temperature is 230 °C; the acquisition mode is full scan.

[0053] Gas chromatography is used to determine the carbon number distribution range of C15 to C21 in transformer oil. Select this section of the carbon number distribution range in the crude oil chromatographic peak, extract the transformer oil fractions in the saturated hydrocarbon and aromatic hydrocarbon, calculate the sum of the characteristic mass fragments of various hydrocarbons using the GC / MS working software, and calculate the group composition using the group composition working software. The results are shown in Table 1.

[0054] Example 16: Weigh 0.100 g of paraffin-based crude oil sample and add 10 ml of n-heptane to dissolve it evenly. Using chromatography technology, Al2O3 with a particle size of 100 to 200 meshes is activated at 550 °C for 2 hours. After adding 1% distilled water and leaving it for 24 hours, it is added to a chromatographic column with a diameter of 10 mm and a column length of 300 mm. The adsorbent dosage is 10 g. Using 30 ml of n-heptane as the mobile phase, the saturated hydrocarbon fraction is obtained by rinsing. Then, 40 ml of dichloromethane + 5% anhydrous ethanol is used for rinsing to obtain the aromatic hydrocarbon fraction, and the rinsing speed is 2 ml / min. The collected saturated hydrocarbon fraction and aromatic hydrocarbon fraction are concentrated by rotary evaporation at a rotation speed of 100 rpm and a temperature of 70 °C. First, the pressure is set to 450 mmHg to evaporate the solvent, and then the pressure is reduced to completely evaporate the solvent. The volume is fixed to 1 ml with n-hexane.

[0055] The saturated hydrocarbon and aromatic hydrocarbon components were measured by GC / MS respectively to obtain the total scan ion current chromatogram. Chromatographic conditions: a non-polar chromatographic column of 30 m × 0.25 mm × 0.1 μm was used; the inlet temperature was 280 °C; the carrier gas was helium; split injection was carried out according to a split ratio of 100:1; temperature programming: starting from 50 °C and rising to 300 °C, and holding until all components flowed out. Mass spectrometry conditions: the GC / MS interface temperature was 280 °C; the mass spectrometry scanning range was from 30 amu to 500 amu; the electron impact ionization energy was 70 eV; the EI ion source temperature was 230 °C; the acquisition mode was total scan.

[0056] Gas chromatography was used to determine the carbon number distribution range of C15 to C21 in transformer oil. The carbon number distribution range in this section of the crude oil chromatographic peak was selected, the transformer oil fractions in the saturated hydrocarbon and aromatic hydrocarbon were extracted, the sum of the characteristic mass fragments of various hydrocarbons was calculated using the GC / MS working software, and the group composition was calculated using the group composition working software. The results are shown in Table 1.

[0057] Example 17: Weigh 0.300 g of paraffin-based crude oil sample and add 20 ml of n-heptane to dissolve it evenly. Using chromatography technology, Al2O3 with 100 to 200 meshes was activated at 550 °C for 2 hours, 1% distilled water was added and left for 24 hours, then it was added to a chromatographic column with a diameter of 10 mm and a column length of 300 mm. The adsorbent dosage was 10 g, and 40 ml of n-heptane was used as the mobile phase to wash to obtain the saturated hydrocarbon component. It was washed with 60 ml of dichloromethane + 5% anhydrous ethanol to obtain the aromatic hydrocarbon component, and the washing speed was 1 ml / min. The collected saturated hydrocarbon component and aromatic hydrocarbon component were concentrated by rotary evaporation at a rotation speed of 120 rpm and a temperature of 50 °C. First, the pressure was set to 450 mmHg to evaporate the solvent, and then the pressure was reduced to completely evaporate the solvent, and it was fixed to 1 ml with n-hexane.

[0058] The saturated hydrocarbon and aromatic hydrocarbon components were measured by GC / MS respectively to obtain the total scan ion current chromatogram. Chromatographic conditions: a non-polar chromatographic column of 30 m × 0.25 mm × 0.1 μm was used; the inlet temperature was 280 °C; the carrier gas was helium; split injection was carried out according to a split ratio of 100:1; temperature programming: starting from 50 °C and rising to 300 °C, and holding until all components flowed out. Mass spectrometry conditions: the GC / MS interface temperature was 280 °C; the mass spectrometry scanning range was from 30 amu to 500 amu; the electron impact ionization energy was 70 eV; the EI ion source temperature was 230 °C; the acquisition mode was total scan.

[0059] Gas chromatography was used to determine the carbon number distribution range of C15 to C21 in transformer oil. The carbon number distribution range in this section of the crude oil chromatographic peak was selected, the transformer oil fractions in the saturated hydrocarbon and aromatic hydrocarbon were extracted, the sum of the characteristic mass fragments of various hydrocarbons was calculated using the GC / MS working software, and the group composition was calculated using the group composition working software. The results are shown in Table 1.

[0060] Example 18: Weigh 0.100 g of paraffin-based crude oil sample and add 10 ml of n-heptane to dissolve it evenly. Using chromatography technology, Al2O3 with a mesh size of 100 to 200 is activated at 550 °C for 2 hours. After adding 1% distilled water and leaving it for 24 hours, it is added to a chromatographic column with a diameter of 10 mm and a column length of 300 mm. The adsorbent dosage is 10 g. Using 30 ml of n-heptane as the mobile phase, the saturated hydrocarbon fraction is obtained by flushing. Then, it is flushed with 40 ml of dichloromethane + 5% anhydrous ethanol to obtain the aromatic hydrocarbon fraction, and the flushing speed is 2 ml / min. The collected saturated hydrocarbon fraction and aromatic hydrocarbon fraction are concentrated by rotary evaporation at a rotation speed of 120 rpm and a temperature of 50 °C. First, the pressure is set to 450 mmHg to evaporate the solvent, and then the pressure is reduced to completely evaporate the solvent. The volume is fixed to 1 ml with n-hexane.

[0061] The saturated hydrocarbon and aromatic hydrocarbon fractions are respectively measured by GC / MS to obtain the full-scan ion current chromatogram. Chromatographic conditions: Use a non-polar 60 m × 0.25 mm × 0.25 μm chromatographic column; the inlet temperature is 280 °C; the carrier gas: helium; split injection is carried out according to a split ratio of 100:1; temperature programming: starting from 50 °C, it is raised to 300 °C and maintained until all components flow out. Mass spectrometry conditions: The GC / MS interface temperature is 280 °C; the mass spectrometry scanning range is 30 amu to 500 amu; the electron impact ionization energy is 70 eV; the EI ion source temperature is 230 °C; the acquisition mode: full scan.

[0062] Gas chromatography is used to determine the carbon number distribution range of C15 to C21 in transformer oil. Select this section of the carbon number distribution range in the crude oil chromatographic peak, extract the transformer oil fractions in the saturated hydrocarbon and aromatic hydrocarbon, calculate the sum of the characteristic mass fragments of various hydrocarbons using the GC / MS working software, and calculate the group composition using the group composition working software. The results are shown in Table 1.

[0063] Example 19: Weigh 0.100 g of paraffin-based crude oil sample and add 10 ml of n-heptane to dissolve it evenly. Using chromatography technology, Al2O3 with a mesh size of 100 to 200 is activated at 550 °C for 2 hours. After adding 1% distilled water and leaving it for 24 hours, it is added to a chromatographic column with a diameter of 10 mm and a column length of 300 mm. The adsorbent dosage is 10 g. Using 30 ml of n-heptane as the mobile phase, the saturated hydrocarbon fraction is obtained by flushing. Then, it is flushed with 40 ml of dichloromethane + 5% anhydrous ethanol to obtain the aromatic hydrocarbon fraction, and the flushing speed is 2 ml / min. The collected saturated hydrocarbon fraction and aromatic hydrocarbon fraction are concentrated by rotary evaporation at a rotation speed of 120 rpm and a temperature of 50 °C. First, the pressure is set to 450 mmHg to evaporate the solvent, and then the pressure is reduced to completely evaporate the solvent. The volume is fixed to 1 ml with n-hexane.

[0064] The saturated hydrocarbon and aromatic hydrocarbon components were measured by GC / MS respectively to obtain the total scan ion current chromatogram. Chromatographic conditions: a weakly polar 30m×0.25mm×0.25μm chromatographic column was used; the inlet temperature was 280°C; the carrier gas was helium; split injection was carried out at a split ratio of 100:1; temperature programming: starting from 50°C and rising to 300°C, and holding until all components flowed out. Mass spectrometry conditions: the GC / MS interface temperature was 280°C; the mass spectrometry scanning range was from 30 amu to 500 amu; the electron impact ionization energy was 70 eV; the EI ion source temperature was 230°C; the acquisition mode was total scan.

[0065] GC / MS was used to determine the carbon number distribution range C15 to C21 of transformer oil. The carbon number distribution range in this section of the crude oil chromatographic peak was selected, and the sum of the characteristic mass fragments of various hydrocarbons was calculated using the GC / MS working software. The group composition was calculated using the group composition working software, and the results are shown in Table 1.

[0066] Example 20: Weigh 0.100 g of paraffin-based crude oil sample and add 10 ml of n-heptane to dissolve it evenly. Using chromatography technology, 100-mesh to 200-mesh Al2O3 was activated at 550°C for 2 hours, added with 1% distilled water and left for 24 hours, then added to a chromatographic column with a diameter of 10 mm and a column length of 300 mm. The adsorbent dosage was 10 g, and 30 ml of n-heptane was used as the mobile phase to wash to obtain the saturated hydrocarbon component. It was washed with 40 ml of dichloromethane + 5% anhydrous ethanol to obtain the aromatic hydrocarbon component, and the washing speed was 2 ml / min. The collected saturated hydrocarbon component and aromatic hydrocarbon component were concentrated by rotary evaporation, with a rotation speed of 120 rpm and a temperature of 50°C. First, the pressure was set to 450 mmHg to evaporate the solvent, and then the pressure was reduced to completely evaporate the solvent, and the volume was fixed to 1 ml with n-hexane.

[0067] The saturated hydrocarbon and aromatic hydrocarbon components were measured by GC / MS respectively to obtain the total scan ion current chromatogram. Chromatographic conditions: a non-polar 30m×0.25mm×0.1μm chromatographic column was used; the inlet temperature was 300°C; the carrier gas was helium; split injection was carried out at a split ratio of 10:1; temperature programming: starting from 35°C and rising to 300°C, and holding until all components flowed out. Mass spectrometry conditions: the GC / MS interface temperature was 280°C; the mass spectrometry scanning range was from 30 amu to 500 amu; the electron impact ionization energy was 70 eV; the EI ion source temperature was 230°C; the acquisition mode was total scan.

[0068] Gas chromatography was used to determine the carbon number distribution range C15 to C21 of transformer oil. The carbon number distribution range in this section of the crude oil chromatographic peak was selected, and the sum of the characteristic mass fragments of various hydrocarbons was calculated using the GC / MS working software. The group composition was calculated using the group composition working software, and the results are shown in Table 1.

[0069] Example 21: Weigh 0.100 g of paraffin-based crude oil sample and add 10 ml of n-heptane to dissolve it evenly. Using chromatography technology, Al2O3 with a mesh size of 100 to 200 is activated at 550 °C for 2 hours. After adding 1% distilled water and leaving it for 24 hours, it is added to a chromatographic column with a diameter of 10 mm and a column length of 300 mm. The adsorbent dosage is 10 g. Using 30 ml of n-heptane as the mobile phase, the saturated hydrocarbon fraction is obtained by flushing. Using 40 ml of dichloromethane + 5% anhydrous ethanol for flushing, the aromatic hydrocarbon fraction is obtained, and the flushing speed is 2 ml / min. The collected saturated hydrocarbon fraction and aromatic hydrocarbon fraction are concentrated by rotary evaporation at a rotation speed of 120 rpm and a temperature of 50 °C. First, the pressure is set to 450 mmHg to evaporate the solvent, and then the pressure is reduced to completely evaporate the solvent. It is made up to 1 ml with n-hexane.

[0070] GC / MS is used to measure the saturated hydrocarbon and aromatic hydrocarbon fractions respectively to obtain the total scan ion current chromatogram. Chromatographic conditions: Use a non-polar 30 m × 0.25 mm × 0.1 μm chromatographic column; the inlet temperature is 280 °C; the carrier gas: helium; split injection is carried out according to a split ratio of 100:1; temperature programming: starting from 50 °C, it is raised to 300 °C and maintained until all components flow out. Mass spectrometry conditions: The GC / MS interface temperature is 300 °C; the mass spectrometry scan range is 30 amu to 500 amu; the electron impact ionization energy is 90 eV; the EI ion source temperature is 200 °C; the acquisition mode: total scan.

[0071] Gas chromatography is used to determine the carbon number distribution range of C15 to C21 in transformer oil. Select this section of the carbon number distribution range in the crude oil chromatographic peak. Use the GC / MS working software to calculate the sum of the characteristic mass fragments of various hydrocarbons, and use the group composition working software to calculate the group composition. The results are shown in Table 1.

[0072] Example 22: Weigh 0.100 g of paraffin-based crude oil sample and add 10 ml of n-heptane to dissolve it evenly. Using chromatography technology, Al2O3 with a mesh size of 100 to 200 is activated at 550 °C for 2 hours. After adding 1% distilled water and leaving it for 24 hours, it is added to a chromatographic column with a diameter of 10 mm and a column length of 300 mm. The adsorbent dosage is 10 g. Using 30 ml of n-heptane as the mobile phase, the saturated hydrocarbon fraction is obtained by flushing. Using 40 ml of dichloromethane + 5% anhydrous ethanol for flushing, the aromatic hydrocarbon fraction is obtained, and the flushing speed is 2 ml / min. The collected saturated hydrocarbon fraction and aromatic hydrocarbon fraction are concentrated by rotary evaporation at a rotation speed of 120 rpm and a temperature of 50 °C. First, the pressure is set to 450 mmHg to evaporate the solvent, and then the pressure is reduced to completely evaporate the solvent. It is made up to 1 ml with n-hexane.

[0073] The saturated hydrocarbon and aromatic hydrocarbon components were measured by GC / MS respectively to obtain the full-scan ion current chromatogram. Chromatographic conditions: a non-polar chromatographic column of 30 m × 0.25 mm × 0.1 μm was used; the inlet temperature was 280 °C; the carrier gas was helium; split injection was carried out at a split ratio of 100:1; temperature programming: starting from 50 °C, rising to 300 °C at a rate of 2 °C / min and holding until all components flowed out. Mass spectrometry conditions: the GC / MS interface temperature was 280 °C; the mass spectrometry scanning range was from 30 amu to 500 amu; the electron impact ionization energy was 70 eV; the EI ion source temperature was 230 °C; the acquisition mode was full scan.

[0074] Gas chromatography was used to determine the carbon number distribution range C15 to C21 of transformer oil. The carbon number distribution range in the crude oil chromatographic peak was selected, and the characteristic mass fragments of various hydrocarbons were calculated using the GC / MS working software. The group composition was calculated using the group composition working software, and the results are shown in Table 1.

[0075] Example 23: Weigh 0.100 g of paraffin-based crude oil sample and add 10 ml of n-heptane to dissolve it evenly. Using chromatography technology, the adsorbent was neutral Al2O3 with a mesh size of 100 to 200, which was activated at 550 °C for 2 hours, then 1% distilled water was added and left for 24 hours, and then it was added to a chromatographic column with a diameter of 10 mm and a length of 300 mm. The adsorbent dosage was 10 g, and 30 ml of n-heptane was used as the mobile phase to wash to obtain the saturated hydrocarbon component. Then, 40 ml of dichloromethane + 5% anhydrous ethanol was used to wash to obtain the aromatic hydrocarbon component, and the washing speed was 2 ml / min. The collected saturated hydrocarbon and aromatic hydrocarbon components were concentrated by rotary evaporation at a rotation speed of 120 rpm and a temperature of 50 °C. First, the pressure was set to 450 mmHg to evaporate the solvent, and then the pressure was reduced to completely evaporate the solvent, and the volume was fixed to 1 ml with n-hexane.

[0076] The saturated hydrocarbon and aromatic hydrocarbon components were measured by GC / MS respectively to obtain the full-scan ion current chromatogram. Chromatographic conditions: a non-polar chromatographic column of 30 m × 0.25 mm × 0.1 μm was used; the inlet temperature was 280 °C; the carrier gas was helium; split injection was carried out at a split ratio of 100:1; temperature programming: starting from 50 °C, rising to 300 °C and holding until all components flowed out. Mass spectrometry conditions: the GC / MS interface temperature was 280 °C; the mass spectrometry scanning range was from 30 amu to 500 amu; the electron impact ionization energy was 70 eV; the EI ion source temperature was 230 °C; the acquisition mode was full scan.

[0077] Gas chromatography was used to determine the carbon number distribution range C15 to C21 of transformer oil. The carbon number distribution range in the crude oil chromatographic peak was selected, and the transformer oil fractions in the saturated hydrocarbon and aromatic hydrocarbon were extracted. The characteristic mass fragments of various hydrocarbons were calculated using the GC / MS working software. The group composition was calculated using the group composition working software, and the results are shown in Table 1.

[0078] Example 24: Weigh 0.100 g of the naphthenic crude oil sample and add 10 ml of n - heptane to dissolve it evenly. Using chromatography technology, neutral Al2O3 with a mesh size of 100 to 200 is activated at 550 °C for 2 hours. After adding 1% distilled water and standing for 24 hours, it is added to a chromatographic column with a diameter of 10 mm and a column length of 300 mm. The adsorbent dosage is 10 g. Using 30 ml of n - heptane as the mobile phase, the saturated hydrocarbon fraction is obtained by rinsing, and 40 ml of dichloromethane is used for rinsing to obtain the aromatic hydrocarbon fraction. The rinsing speed is 2 ml / min.

[0079] The saturated hydrocarbon and aromatic hydrocarbon fractions are respectively measured by GC / MS to obtain the total scan ion current chromatogram. Chromatographic conditions: Use a non - polar 30 m×0.25 mm×0.1 μm chromatographic column; the inlet temperature is 280 °C; the carrier gas: helium; split injection is carried out according to a split ratio of 100:1; temperature programming: starting from 50 °C and rising to 300 °C, and maintaining until all components flow out. Mass spectrometry conditions: The GC / MS interface temperature is 280 °C; the mass spectrometry scanning range is 30 amu to 500 amu; the electron impact ionization energy is 70 eV; the EI ion source temperature is 230 °C; the acquisition mode: total scan.

[0080] By selecting the carbon number distribution range C15 to C21 of the chromatographic peaks, selecting this section of the carbon number distribution range in the crude oil chromatographic peaks, extracting the transformer oil fractions in the saturated hydrocarbons and aromatic hydrocarbons, calculating the sum of the characteristic mass fragments of various hydrocarbons using the GC / MS working software, and using the group composition working software for calculation to obtain the group composition. The results are shown in Table 1.

[0081] Example 25: Weigh 0.100 g of the paraffinic crude oil sample and add 10 ml of n - heptane to dissolve it evenly. Using chromatography technology, Al2O3 with a mesh size of 200 is activated at 550 °C for 2 hours. After adding 1% distilled water and standing for 24 hours, it is added to a chromatographic column with a diameter of 10 mm and a column length of 750 mm until it reaches the scale line. Using 120 ml of n - heptane as the mobile phase, the saturated hydrocarbon fraction is obtained by rinsing, and 120 ml of dichloromethane + 5% anhydrous ethanol is used for rinsing to obtain the aromatic hydrocarbon fraction. The rinsing speed is 2 ml / min. The collected saturated hydrocarbon fraction and aromatic hydrocarbon fraction are concentrated by rotary evaporation, with a rotation speed of 120 rpm and a temperature of 50 °C. First, the pressure is set to 450 mmHg to evaporate the solvent, and then the pressure is reduced to completely evaporate the solvent, and the volume is fixed to 1 ml with n - hexane.

[0082] The saturated hydrocarbon and aromatic hydrocarbon components were measured by GC / MS respectively to obtain the total scan ion current chromatogram. Chromatographic conditions: a non-polar chromatographic column of 30 m × 0.25 mm × 0.1 μm was used; the inlet temperature was 280 °C; the carrier gas was helium; split injection was carried out according to a split ratio of 100:1; the temperature programming was as follows: starting from 50 °C, the temperature was raised to 300 °C and maintained until all components flowed out. Mass spectrometry conditions: the GC / MS interface temperature was 280 °C; the mass spectrometry scanning range was from 30 amu to 500 amu; the electron impact ionization energy was 70 eV; the EI ion source temperature was 230 °C; the acquisition mode was total scan.

[0083] Gas chromatography was used to determine the diesel carbon number distribution range of C10 to C16. The carbon number distribution range in this section was selected from the crude oil chromatographic peaks, and the diesel fractions in the saturated hydrocarbons and aromatic hydrocarbons were extracted. The characteristic mass fragments of various hydrocarbons were summed up using the GC / MS working software, and the group composition was calculated using the group composition working software. The results are shown in Table 1.

[0084] Example 26: Weigh 0.100 g of paraffin-based crude oil sample and add 10 ml of n-heptane to dissolve it evenly. Using chromatography technology, 200-mesh Al2O3 was activated at 550 °C for 2 hours. After adding 1% distilled water and standing for 24 hours, it was added to a chromatographic column with a diameter of 10 mm and a column length of 750 mm up to the scale line. Using 120 ml of n-heptane as the mobile phase, the saturated hydrocarbon component was obtained by rinsing. Using 120 ml of dichloromethane + 5% anhydrous ethanol for rinsing, the aromatic hydrocarbon component was obtained, and the rinsing speed was 2 ml / min. The collected saturated hydrocarbon component and aromatic hydrocarbon component were concentrated by rotary evaporation, with a rotation speed of 120 rpm and a temperature of 50 °C. First, the pressure was set to 450 mmHg to evaporate the solvent, and then the pressure was reduced to completely evaporate the solvent, and the volume was fixed to 1 ml with n-hexane.

[0085] The saturated hydrocarbon and aromatic hydrocarbon components were measured by GC / MS respectively to obtain the total scan ion current chromatogram. Chromatographic conditions: a non-polar chromatographic column of 30 m × 0.25 mm × 0.1 μm was used; the inlet temperature was 280 °C; the carrier gas was helium; split injection was carried out according to a split ratio of 100:1; the temperature programming was as follows: starting from 50 °C, the temperature was raised to 300 °C and maintained until all components flowed out. Mass spectrometry conditions: the GC / MS interface temperature was 280 °C; the mass spectrometry scanning range was from 30 amu to 500 amu; the electron impact ionization energy was 70 eV; the EI ion source temperature was 230 °C; the acquisition mode was total scan.

[0086] Gas chromatography was used to determine the diesel carbon number distribution range of C18 to C27. The carbon number distribution range in this section was selected from the crude oil chromatographic peaks, and the refrigeration oil fractions in the saturated hydrocarbons and aromatic hydrocarbons were extracted. The characteristic mass fragments of various hydrocarbons were summed up using the GC / MS working software, and the group composition was calculated using the group composition working software. The results are shown in Table 1.

[0087] Example 27: Weigh 0.100 g of paraffin-based crude oil sample and add 10 ml of n-heptane to dissolve it evenly. Using chromatography technology, 200-mesh Al2O3 is activated at 550 °C for 2 hours. After adding 1% distilled water and standing for 24 hours, it is added to a chromatographic column with a diameter of 10 mm and a column length of 750 mm up to the scale line. Using 120 ml of n-heptane as the mobile phase, the saturated hydrocarbon fraction is obtained by rinsing. Using 120 ml of dichloromethane + 5% absolute ethanol for rinsing, the aromatic hydrocarbon fraction is obtained, and the rinsing speed is 2 ml / min. The collected saturated hydrocarbon fraction and aromatic hydrocarbon fraction are concentrated by rotary evaporation at a rotation speed of 120 rpm and a temperature of 50 °C. First, the pressure is set to 450 mmHg to evaporate the solvent, and then the pressure is reduced to completely evaporate the solvent, and the volume is fixed to 1 ml with n-hexane.

[0088] The saturated hydrocarbon and aromatic hydrocarbon fractions are respectively measured by GC / MS to obtain the total scan ion current chromatogram. Chromatographic conditions: Use a non-polar 30 m × 0.25 mm × 0.1 μm chromatographic column; the inlet temperature is 280 °C; the carrier gas: helium; split injection is carried out according to a split ratio of 100:1; temperature programming: starting from 50 °C and rising to 300 °C, and maintaining until all components flow out. Mass spectrometry conditions: The GC / MS interface temperature is 280 °C; the mass spectrometry scanning range is 30 amu to 500 amu; the electron impact ionization energy is 70 eV; the EI ion source temperature is 230 °C; the acquisition method: total scan.

[0089] Gas chromatography is used to determine the carbon number distribution range of diesel from C22 to C30. Select this section of the carbon number distribution range in the crude oil chromatographic peak, and respectively extract the second key fractions in the saturated hydrocarbons and aromatic hydrocarbons. The characteristic mass fragments of various hydrocarbons are summed up using the GC / MS working software, and the group composition is calculated using the group composition working software. The results are shown in Table 1.

[0090] The crude oil samples of Examples 23 to 27 are experimented with by the conventional true boiling point distillation cutting method. The group composition working software is directly used to calculate the distillate oil. The experimental results are shown in Table 1. The results show that the component contents in the transformer oil, diesel, refrigeration oil, and the second key fraction measured by the method of the present invention are consistent with those of the conventional method.

[0091] In summary, the present invention provides a method for analyzing the group composition of specific fractions of crude oil. This method uses chromatography technology to separate crude oil samples, and the separated saturated hydrocarbons and aromatic hydrocarbons are measured by GC / MS. Quantitative analysis of the group composition is achieved by selecting a specific carbon number distribution range of the fraction for analysis and calculation. This method can quickly realize the analysis of the group composition of specific fractions of crude oil. Compared with traditional crude oil evaluation, the sample amount required for analysis is small, the analysis time is short, the analysis efficiency is high, and the results are accurate.

[0092] The above technical features constitute an embodiment of the present invention, which has strong adaptability and implementation effects. Non-essential technical features can be increased or decreased according to actual needs to meet the requirements of different situations.

[0093]

Claims

1. A method for analyzing the group composition of specific fractions of crude oil, characterized in that The steps are as follows: First step, weigh 0.05 g to 0.30 g of crude oil sample, add 3 ml to 20 ml of n-alkane for dissolution to obtain a crude oil sample solution; Second step, separate the crude oil sample solution by chromatography to obtain a saturated hydrocarbon component solution and an aromatic hydrocarbon component solution. Among them, the adsorbent used in the chromatography is an activated solid oxide adsorbent. The length of the chromatography column is 250 mm to 750 mm, the diameter is 10 mm to 20 mm, and the amount of adsorbent used is 5 g to 30 g; Third step, use GC / MS to measure the saturated hydrocarbon components in the saturated hydrocarbon solution and the aromatic hydrocarbon components in the aromatic hydrocarbon solution respectively, obtain the total ion current chromatogram of saturated hydrocarbons and the total ion current chromatogram of aromatic hydrocarbons respectively, analyze the total ion current chromatogram of saturated hydrocarbons and the total ion current chromatogram of aromatic hydrocarbons, and calculate the group composition of a specific fraction; In the first step, the n-alkane is one of C5 to C7 n-alkanes; In the second step, the specific steps for separating the crude oil sample solution into a saturated hydrocarbon component solution and an aromatic hydrocarbon component solution by chromatography are as follows: Transfer the crude oil sample solution into the chromatography column. After the added sample solution disappears from the surface of the adsorbent, add 20 ml to 120 ml of n-alkane identical to the sample solvent for elution. The elution rate is 1 ml / min to 3 ml / min. Collect the n-alkane eluate, concentrate and fix the volume to obtain the saturated hydrocarbon component solution. Then add 20 ml to 120 ml of a mixed solution of alcohol and chlorinated hydrocarbon solvent to the chromatography column for elution. The elution rate is 1 ml / min to 3 ml / min. Collect the eluate of the mixed solution of alcohol and chlorinated hydrocarbon solvent, concentrate and fix the volume to obtain the aromatic hydrocarbon component solution; In the mixed solution of alcohol and chlorinated hydrocarbon solvent, the alcohol is one of C1 to C3 alcohols, the chlorinated hydrocarbon is dichloromethane or trichloromethane, and the volume ratio of alcohol to chlorinated hydrocarbon is 0:1 to 1:10; The solid oxide adsorbent is one of Fe2O3, Al2O3, MnO2 and SiO2, and the particle size of the solid oxide adsorbent is 100 mesh to 300 mesh; In the third step, the GC / MS chromatographic conditions are as follows: The chromatographic column is a non-polar chromatographic column or a weakly polar chromatographic column, the column length is 30 m to 60 m, the diameter is 0.25 mm to 0.5 mm, the inlet temperature is 280 °C to 300 °C, the carrier gas is helium, the split injection split ratio is 10:1 to 100:1, and the temperature programming is starting from 35 °C to 50 °C, rising to 300 °C and holding until all components flow out; The specific fraction of the crude oil is the crude oil fraction with a carbon number range of C10 to C32.

2. The method for analyzing the group composition of specific fractions of crude oil according to claim 1, wherein In the second step, the activation process is to heat the solid oxide adsorbent at 400 °C to 550 °C for 1 h to 5 h, cool to room temperature, add distilled water with a mass ratio of 0.5% to 5%, and let it stand for 12 h to 48 h for standby.

3. The method for analyzing the group composition of specific fractions of crude oil according to claim 1 or 2, characterized in that In the third step, the GC / MS mass spectrometry conditions are as follows: The GC / MS interface temperature is 280 °C to 300 °C, the mass spectrometry scanning range is 30 amu to 500 amu, the electron impact ionization energy is 70 eV to 90 eV, the EI ion source temperature is 200 °C to 230 °C, and the acquisition mode is full scan.

4. The method for analyzing the group composition of a specific fraction of crude oil according to claim 3, characterized in that In the third step, the calculation is to select the carbon number distribution range of specific fraction chromatographic peaks in the GC / MS chromatogram, calculate the sum of characteristic mass fragments of various hydrocarbons through the GC / MS workstation, and use the group composition working software that meets the requirements of ASTM D2425 or ASTM D3239 methods for analysis and calculation to obtain the group composition.

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