A method for separating phenanthrene compounds from a mixed aromatic hydrocarbon solution and its application

Abstract

This application relates to the technical field of oil and gas exploration, specifically to a method for separating phenanthrene compounds from a mixed aromatic hydrocarbon solution and its application. The method includes the following steps: molecular sieve pretreatment: extracting undemolded MCM-41 molecular sieves using dichloromethane as a solvent; sample pretreatment: adding crude silica gel to the mixed aromatic hydrocarbon solution, evaporating the solvent to obtain silica gel particles containing mixed aromatic hydrocarbons; column fabrication: sequentially adding the extracted MCM-41 molecular sieve and the silica gel particles containing mixed aromatic hydrocarbons into a chromatography column, compacting the MCM-41 molecular sieve and silica gel particles to obtain the chromatography column; sample separation: adding an organic solvent to the chromatography column to separate the phenanthrene compounds. This application aims to improve the problems of unclear separation effects or catalysis of aromatic hydrocarbon samples when using chromatography to separate phenanthrene compounds from aromatic hydrocarbon samples.

Description

Technical Field

[0001] This application relates to the technical field of oil and gas exploration, specifically to a method for separating phenanthrene compounds from a mixed aromatic hydrocarbon solution and its application. Background Technology

[0002] Phenanthrene compounds are widely used to study the maturity of crude oil and source rocks, as well as for oil-source correlation. Isotopic determination of phenanthrene compounds can corroborate conclusions and broaden the scope of research. When performing isotopic determination on aromatic monomers, the content of the monomer compounds needs to reach a certain value. The content of various aromatic compounds varies in crude oil or chloroform bitumen A. Among common aromatic compounds, naphthalene series compounds are generally present in higher amounts and are easy to determine isotopically. However, phenanthrene series compounds are usually masked by the high content of naphthalene series compounds, making isotopic determination difficult. Therefore, phenanthrene compounds in crude oil are generally not directly determined isotopically; their concentration needs to be increased through purification and other methods.

[0003] Chromatography is a method of separation based on the difference in partition coefficients between the stationary and mobile phases, typically used for the separation of monomeric compounds. Molecular sieves, with their microporous structures, can be used as chromatographic materials, enabling efficient separation of compounds based on their pore size. Organic template agents play a crucial role in the synthesis of molecular sieves, helping to form their specific pore structure. However, these organic template agents usually need to be removed after synthesis to allow the pores of the molecular sieve to open. Currently, high-temperature calcination is commonly used for demolding molecular sieves. Summary of the Invention

[0004] This application provides a method for separating phenanthrene compounds from a mixed aromatic hydrocarbon solution and its application, aiming to solve the problems of unclear separation effect or catalysis of aromatic hydrocarbon samples when using chromatography to separate phenanthrene compounds from aromatic hydrocarbon samples. The technical solution adopted in this application is as follows:

[0005] In a first aspect, this application relates to a method for separating phenanthrene compounds from a mixed aromatic hydrocarbon solution, comprising the following steps:

[0006] Molecular sieve pretreatment: Dichloromethane was used as a solvent to extract the undemolded MCM-41 molecular sieve;

[0007] Sample pretreatment: Add crude silica gel to a mixed aromatic hydrocarbon solution, evaporate the solvent, and obtain silica gel particles containing mixed aromatic hydrocarbons;

[0008] Preparation of the chromatographic column: The extracted MCM-41 molecular sieve and the silica gel particles containing mixed aromatics were added sequentially into the chromatography column, and the MCM-41 molecular sieve and silica gel particles were compacted to obtain the chromatographic column.

[0009] Sample separation: An organic solvent is added to the chromatographic column to separate phenanthrene compounds.

[0010] By employing the above technical solution, undemolded MCM-41 molecular sieves are selected. The smaller pore size of these sieves is beneficial for the adsorption of phenanthrene compounds. Dichloromethane is used to extract from the MCM-41 molecular sieve to remove the influence of the molecular sieve template agent on the sample, while avoiding catalysis of the aromatic hydrocarbon sample due to the direct use of demolded MCM-41 molecular sieves. This method successfully separates phenanthrene compounds from mixed aromatic hydrocarbon samples, achieving good separation results.

[0011] Furthermore, during sample separation, allowing the column to stand after adding organic solvent helps the solvent better adsorb phenanthrene compounds. Tamp the column to ensure uniform chromatography speed under solvent action.

[0012] In a specific implementation, optionally, the organic solvent used in the sample separation is n-hexane.

[0013] Through extensive comparative experiments using the above technical solutions, it has been demonstrated that only n-hexane solvent, when passing through MCM-41 molecular sieve, can adsorb phenanthrene compounds. Other solvents, such as dichloromethane and isooctane, do not have this effect or the effect is not obvious.

[0014] In a specific implementation, as an option, the sample pretreatment may further include: separating the mixed aromatic hydrocarbon solution from crude oil.

[0015] In a specific implementation, optionally, the separation of the mixed aromatics solution from crude oil includes:

[0016] The crude oil was dissolved in hexane, allowed to stand, and after the asphaltene precipitated, it was filtered to separate the mixed aromatic hydrocarbon solution from the filtrate.

[0017] By employing the above technical solution, a mixed aromatic hydrocarbon solution is separated from crude oil, and then phenanthrene compounds within the mixed aromatic hydrocarbons are further separated. This facilitates the evaluation of crude oil maturity through further analysis of phenanthrene compounds. Furthermore, removing asphaltenes through precipitation before crude oil separation prevents asphaltenes from interfering with the separation process.

[0018] In a specific implementation, optionally, the crude oil has a mass fraction of 0.05 to 0.06 parts, and the extracted MCM-41 molecular sieve has a mass fraction of 1.4 to 1.6 parts.

[0019] By adopting the above technical solution, and with a fixed amount of crude oil sample, the amount of MCM-41 molecular sieve used after extraction was determined through experiments. Within this range, phenanthrene compounds can be completely adsorbed and effectively separated. Furthermore, phenanthrene compounds can be dripped out when the amount of organic solvent used is within 30 ml.

[0020] In a specific embodiment, as an option, after adding an organic solvent to the chromatographic column, the sample separation process further includes: pressurizing the chromatographic column by introducing nitrogen gas to separate phenanthrene compounds.

[0021] By adopting the above technical solution, due to the small particle size of MCM-41 molecular sieve, nitrogen gas is introduced during the chromatography process to provide sufficient pressure, thereby allowing phenanthrene compounds to flow out normally.

[0022] In a specific embodiment, optionally, the sample separation further includes: after adding an organic solvent to the chromatographic column, phenanthrene compounds appear in the 8th to 9th mL of liquid that is dripped out.

[0023] By adopting the above technical solution and the separation method described in this application, based on a determined crude oil sample volume, the first 7-8 mL of effluent mainly consists of aromatic hydrocarbons other than phenanthrene compounds, while phenanthrene compounds effluent in the 8th-9th mL. This results in a larger volume of solution containing phenanthrene compounds, reducing unnecessary loss of these compounds.

[0024] In a specific embodiment, optionally, the fabrication of the chromatographic column further includes: the diameter of the chromatographic column is 0.8-0.9 cm, and the height of the chromatographic column is 35-38 cm.

[0025] By adopting the above technical solution, the chromatography column used in the chromatography separation process must have a certain degree of separation. Experimental tests show that using a chromatography column with a diameter of 0.8-0.9 cm and a height of 35-38 cm, and adding 1.4-1.6 g of treated MCM-41 molecular sieve can achieve 2 / 3 of the height of the chromatography column. Finally, adding 0.4-0.8 g of silica gel particles containing mixed aromatic hydrocarbon samples can separate phenanthrene compounds and other aromatic hydrocarbons, fully meeting the separation requirements.

[0026] In a specific embodiment, as an option, the molecular sieve pretreatment further includes: the extraction time of the undemolded MCM-41 molecular sieve is 1.5 to 2 hours.

[0027] By adopting the above technical solution, when extracting MCM-41 molecular sieve with dichloromethane, the extraction time is ensured to be long enough, which is conducive to the complete removal of template agent and prevents template agent from contaminating the mixed aromatic hydrocarbon sample.

[0028] In a specific implementation, as an option, the molecular sieve pretreatment further includes: extracting the undemolded MCM-41 molecular sieve using a Soxhlet extractor.

[0029] In a specific implementation, optionally, the coarse silica gel used in the sample pretreatment has a mesh size of 80 to 100 mesh.

[0030] Secondly, this application relates to the application of the method for separating phenanthrene compounds from a mixed aromatic solution as described above in oil and gas exploration.

[0031] In summary, the advantages of this application over the prior art include:

[0032] 1. This application employs chromatography to separate phenanthrene compounds from a mixed aromatic hydrocarbon solution. Extensive experimental verification demonstrated that, compared to other molecular sieve materials such as NaY and USY molecular sieves, this application selected undemolded MCM-41 molecular sieve as the chromatographic material. Furthermore, pretreatment of the MCM-41 molecular sieve with dichloromethane achieved superior separation of phenanthrene compounds. In the full-scan TIC chromatogram of the separated solution containing phenanthrene compounds, the compounds are clearly visible. The mixed aromatic hydrocarbon sample is neither contaminated nor catalyzed, resulting in unexpectedly better separation. Moreover, using undemolded MCM-41 molecular sieve further simplifies the operational process.

[0033] 2. This application selects n-hexane as a solvent. Extensive comparative experiments have shown that n-hexane solvent can adsorb phenanthrene compounds when passing through MCM-41 molecular sieve, while dichloromethane and isooctane will result in poor separation effect or separation failure of phenanthrene compounds.

[0034] 3. The separation method for phenanthrene compounds in this application is applicable to both mixed aromatic hydrocarbon samples in which phenanthrene compounds are visible on the original full-scan TIC chromatogram and mixed aromatic hydrocarbon samples in which phenanthrene compounds are not visible on the original full-scan TIC chromatogram. This indicates that the separation method is applicable to a wide range of samples with phenanthrene compound content and also has good separation effect on samples with low phenanthrene compound content.

[0035] 4. Among phenanthrene compounds, the isotopes of phenanthrene, methylphenanthrene, and dimethylphenanthrene change accordingly with the maturity of crude oil. By separating phenanthrene compounds using the method described in this invention, and further performing isotopic analysis on the resulting solution containing phenanthrene compounds, this method can serve as a characteristic for evaluating the maturity of crude oil samples, which is of great significance for oil and gas exploration. Attached Figure Description

[0036] Figure 1 The image shows a full scan TIC plot of the liquid flowing out when the NaY molecular sieve is demolded and dichloromethane is used as a solvent.

[0037] Figure 2 The image shows a full scan TIC plot of the liquid flowing out when the NaY molecular sieve is demolded and n-hexane is used as a solvent.

[0038] Figure 3 The image shows a full scan TIC plot of the liquid flowing out when the NaY molecular sieve is demolded and isooctane is used as a solvent.

[0039] Figure 4 The image shows a full scan TIC plot of the liquid flowing out when the USY molecular sieve is demolded and dichloromethane is used as a solvent.

[0040] Figure 5 The image shows a full scan TIC plot of the liquid flowing out when the USY molecular sieve is demolded and n-pentane is used as a solvent.

[0041] Figure 6 The image shows a full scan TIC plot of the liquid flowing out when using a demolded β molecular sieve and n-hexane as a solvent.

[0042] Figure 7 The image shows a full scan TIC plot of the liquid flowing out when using demolded MCM-41 molecular sieve and dichloromethane as solvent.

[0043] Figure 8 The image shows a full scan TIC plot of the liquid flowing out when using demolded MCM-41 molecular sieve and n-hexane as solvent.

[0044] Figure 9 The image shows a full scan TIC plot of the liquid flowing out when using demolded MCM-41 molecular sieve and n-pentane as solvent.

[0045] Figure 10 The image shows a full scan TIC plot of the liquid flowing out when the MCM-41 molecular sieve is demolded and isooctane is used as a solvent.

[0046] Figure 11 The image shows a full scan TIC plot of the liquid flowing out when using undemolded MCM-41 molecular sieve and dichloromethane as solvent.

[0047] Figure 12 The image shows a full scan TIC plot of the liquid flowing out when using undemolded MCM-41 molecular sieve and n-hexane as solvent.

[0048] Figure 13 This is a full scan TIC image of the mixed aromatic hydrocarbon solution before separation in Example 1;

[0049] Figure 14 This is a full scan TIC image of solution A in Example 1;

[0050] Figure 15 This is a full scan TIC image of solution B in Example 1;

[0051] Figure 16 This is a full scan TIC image of the mixed aromatic hydrocarbon solution before separation in Example 2;

[0052] Figure 17 This is the full scan TIC image of solution A in Example 2;

[0053] Figure 18 This is the full scan TIC image of solution B in Example 2;

[0054] Figure 19 This is a full scan TIC image of the first 30 ml of liquid in Example 5;

[0055] Figure 20 This is a full scan TIC image of the last 10 ml of liquid in Example 5. Detailed Implementation

[0056] The inventors used demolded NaY molecular sieves as the chromatographic column material to separate phenanthrene compounds in mixed aromatic hydrocarbon samples. Specifically, the NaY molecular sieves were added to the chromatography column, using dichloromethane, n-hexane, and isooctane as solvents, respectively. The elution liquid from the column was then analyzed by chromatography-mass spectrometry (GC-MS), and the resulting full-scan TIC chromatograms are shown below. Figures 1-3 As shown. Among them, Figure 1 This is a full scan TIC plot using dichloromethane as the solvent. Figure 2 This is a full scan TIC plot using n-hexane as the solvent. Figure 3 This is a full-scan TIC image using isooctane as a solvent. The inventors discovered that when using NaY molecular sieve and dichloromethane as solvents, aromatic compounds flowed out simultaneously in the full-scan TIC image of the effluent, with no separation effect; when using n-hexane as a solvent, the aromatics were adsorbed onto the NaY molecular sieve, and phenanthrene compounds could not be separated; and when using isooctane as a solvent, the aromatic sample underwent catalysis, generating other substances, and the separation of phenanthrene compounds failed.

[0057] The inventors further used demolded USY molecular sieves as the chromatographic column material, and dichloromethane and n-pentane as solvents, respectively. The eluting liquid from the chromatography column was then analyzed by chromatography-mass spectrometry, and the obtained full-scan TIC chromatograms are shown below. Figures 4-5 As shown. Figure 4 This is a full scan TIC plot using dichloromethane as the solvent. Figure 5 This is a full-scan TIC image with n-pentane as the solvent. The inventors discovered that when using USY molecular sieve and dichloromethane as solvents, aromatics are catalyzed; when using n-pentane as solvent, aromatic samples are adsorbed onto the USY molecular sieve, and the separation of phenanthrene compounds fails.

[0058] The inventors also used demolded β-molecular sieves as the column material and n-hexane as the solvent. The resulting full-scan TIC chromatogram of the elution liquid is shown below. Figure 6 As shown, aromatic compounds flow out simultaneously, but there is no separation effect on phenanthrene compounds in the aromatics.

[0059] The inventors further used the demembraned MCM-41 molecular sieve as the chromatographic column material and dichloromethane, n-hexane, n-pentane, and isooctane as solvents to perform chromatographic-mass spectrometry analysis on the eluent. The obtained full-scan TIC chromatograms are shown below. Figures 7-10 As shown, all cases exhibited poor separation of phenanthrene compounds in the effluent, or catalysis of aromatic hydrocarbons.

[0060] The inventors further used untreated, unde-delaminated MCM-41 molecular sieves as the chromatographic column material, and dichloromethane and n-hexane as solvents, respectively, to perform chromatographic-mass spectrometry analysis on the eluent. The obtained full-scan TIC chromatograms are shown below. Figures 11-12 As shown, contaminants were found in the outflowing liquid, and the separation of phenanthrene compounds failed.

[0061] Based on the above experimental results, the inventors discovered that when using chromatography to separate phenanthrene compounds from aromatic samples, the separation effect is usually not obvious or the aromatic sample is catalyzed, leading to the failure of phenanthrene compound separation.

[0062] Therefore, in order to improve the separation effect of phenanthrene compounds, the inventors further developed and created this invention.

[0063] The present application will be described in detail below through specific embodiments:

[0064] Example 1

[0065] In this embodiment, crude oil from well section 3486–3524m in the Ganchaigou area of ​​the Qaidam Oilfield was selected for phenanthrene compound separation experiments.

[0066] The specific steps for separating phenanthrene compounds include:

[0067] (1) Molecular sieve pretreatment: Take the undemolded MCM-41 molecular sieve (purchased from Taobao manufacturer "Molecular Sieve Catalysis Chemical Business Department" all-silica undemolded MCM-41 molecular sieve), put it into a Soxhlet extractor, use dichloromethane as solvent, extract the undemolded MCM-41 molecular sieve for 1.5h, take it out and dry it in a fume hood for later use.

[0068] (2) Sample pretreatment: Take 50 mg of crude oil, dissolve it in n-hexane, let it stand for 12 h, and then filter to precipitate the asphaltene. According to the SY / T5119-2016 standard, separate the saturated hydrocarbon solution and the mixed aromatic hydrocarbon solution from the filtrate after the asphaltene precipitation. After concentrating the mixed aromatic hydrocarbon solution to 0.5 mL, add 0.5 g of crude silica gel (80-100 mesh) to the concentrated mixed aromatic hydrocarbon solution, evaporate the solvent, and obtain silica gel particles containing mixed aromatic hydrocarbons for later use.

[0069] (3) Preparation of chromatographic column: Prepare a chromatographic column with a diameter of 0.8 cm and a height of 35 cm, add 1.5 g of the MCM-41 molecular sieve pretreated in (1), then add the silica gel particles containing mixed aromatics in (2), and tamp down the MCM-41 molecular sieve and silica gel particles to obtain the chromatographic column.

[0070] (4) Sample separation: Add hexane solvent to the chromatographic column in (3) to wet it, let it stand for half an hour, then introduce nitrogen gas into the chromatographic column. Under nitrogen pressure, drip the liquid with hexane solvent at a rate of 1 drop / second. For the first 6 ml, after dripping 2 ml of liquid, perform a full chromatographic-mass spectrometry scan on the liquid. Starting from the 7th ml, after dripping 1 ml of liquid, determine the time point at which phenanthrene compounds appear.

[0071] In this embodiment, the full scan TIC chromatogram of the mixed aromatic hydrocarbon solution before MCM-41 molecular sieve separation is shown below. Figure 13 As shown, by Figure 13 Phenanthrene compounds were observed, but not prominently. Serial chromatography-mass spectrometry (TCMS) analysis revealed the presence of phenanthrene compounds after the 9th mL of liquid was dispensed. Specifically, the first 8 mL of dispensed liquid was solution A, and the TIC chromatogram of solution A is shown below. Figure 14 As shown, from Figure 14 No phenanthrene compounds were observed. After the appearance of phenanthrene compounds, 25 mL of solution B was added dropwise at the same rate. The full scan TIC chromatogram of solution B is shown below. Figure 15 As shown.

[0072] Depend on Figures 13-15 As can be seen, phenanthrene compounds are present, but not clearly, in the full-scan TIC chromatogram of the mixed aromatic hydrocarbon solution before separation. No phenanthrene compounds are visible in the first 8 mL of solution A, but they are clearly visible in the full-scan TIC chromatogram of solution B after the 8 mL mark. The phenanthrene compounds were successfully separated into solution B.

[0073] according to Figure 15 Further qualitative analysis was performed on the phenanthrene compounds in solution B. The qualitative analysis of the phenanthrene compounds in solution B is shown in Table 1.

[0074] Table 1

[0075]

[0076]

[0077] Example 2

[0078] In this embodiment, crude oil from the Tazhong 62 well in the Tarim Oilfield was selected for the separation experiment of phenanthrene compounds.

[0079] The specific steps for separating phenanthrene compounds include:

[0080] (1) Molecular sieve pretreatment: Take the undemolded MCM-41 molecular sieve (purchased from Taobao manufacturer "Molecular Sieve Catalysis Chemical Business Department" all-silica undemolded MCM-41 molecular sieve), put it into a Soxhlet extractor, use dichloromethane as solvent, extract the undemolded MCM-41 molecular sieve for 2 hours, take it out and dry it in a fume hood with filter paper, and wait for use.

[0081] (2) Sample pretreatment: Take 60 mg of crude oil, dissolve it in n-hexane, let it stand for 12 h, and then filter to remove the precipitated asphaltene. According to the SY / T5119-2016 standard, separate the saturated hydrocarbon solution and the mixed aromatic hydrocarbon solution from the sample after the asphaltene precipitation. Concentrate the mixed aromatic hydrocarbon solution to 0.5 mL, then add 0.8 g of crude silica gel (80-100 mesh) to the concentrated mixed aromatic hydrocarbon solution, evaporate the solvent, and obtain silica gel particles containing mixed aromatic hydrocarbons for later use.

[0082] (3) Preparation of chromatographic column: Prepare a chromatographic column with a diameter of 0.9 cm and a height of 38 cm, add 1.6 g of the MCM-41 molecular sieve pretreated in (1), then add the silica gel particles containing mixed aromatics in (2), and tamp the MCM-41 molecular sieve and silica gel particles to obtain the chromatographic column.

[0083] (4) Sample separation: Add hexane solvent to the chromatographic column in (3) to wet it, let it stand for half an hour, then introduce nitrogen gas into the chromatographic column. Under nitrogen pressure, drip the liquid with hexane solvent at a rate of 1 drop / second. For the first 6 ml, after dripping 2 ml of liquid, perform a full chromatographic-mass spectrometry scan on the liquid. Starting from the 7th ml, after dripping 1 ml of liquid, determine the time point at which phenanthrene compounds appear.

[0084] In this embodiment, the full scan TIC chromatogram of the mixed aromatic hydrocarbon solution before MCM-41 molecular sieve separation is shown below. Figure 13 As shown, by Figure 13 Phenanthrene compounds were observed, but not prominently. Serial chromatography-mass spectrometry (TCMS) analysis revealed the presence of phenanthrene compounds after the 8th mL of liquid was dispensed. Specifically, the first 7 mL of dispensed liquid was solution A, and the TIC chromatogram of solution A is shown below. Figure 16 As shown, from Figure 16 No phenanthrene compounds were observed. After the appearance of phenanthrene compounds, 25 mL of solution B was added dropwise at the same rate. The full scan TIC chromatogram of solution B is shown below. Figure 17 As shown.

[0085] Depend on Figures 16-18 It can be seen that phenanthrene compounds are difficult to distinguish in the full-scan TIC chromatogram of the mixed aromatic hydrocarbon solution before separation, indicating that the content of phenanthrene compounds in the mixed aromatic hydrocarbon solution before separation is extremely low. No phenanthrene compounds are visible in the full-scan TIC chromatogram of the first 7 mL of solution A, but they are clearly visible in the full-scan TIC chromatogram of solution B after the 7 mL mark. The phenanthrene compounds were successfully separated into solution B.

[0086] Example 3

[0087] The difference between this embodiment and embodiment 1 is that in step (3), 1.4g of the pretreated MCM-41 molecular sieve from (1) is added, while the other processes are the same.

[0088] Correspondingly, according to the full scan analysis results of chromatography-mass spectrometry, phenanthrene compounds also appeared when the 9 ml of liquid was dispensed in this embodiment, and the phenanthrene compounds were successfully separated.

[0089] Example 4

[0090] The difference between this embodiment and embodiment 1 is that in step (3), 3g of the pretreated MCM-41 molecular sieve from (1) is added, while the other processes are the same.

[0091] In this embodiment, 30 mL of n-hexane was first added, and the flushed liquid was subjected to full scan chromatography-mass spectrometry analysis. The full scan TIC chromatogram of the first 30 mL of liquid is shown below. Figure 19 As shown, Figure 19 No phenanthrene compounds were observed. The column was then rinsed with 10 mL of n-hexane, and the eluent was analyzed by full-scan chromatography-mass spectrometry (TCMS). The TIC chromatogram of the last 10 mL of eluent is shown below. Figure 20 As shown, by Figure 20 It can be seen that phenanthrene compounds can be observed, but other aromatic compounds are also present, resulting in poor separation.

[0092] As shown in the above examples, when the sample amount remains constant at 50 mg, phenanthrene compounds tend to elute prematurely when the amount of MCM-41 molecular sieve added is less than 1.4 g. When the amount of MCM-41 molecular sieve added is greater than 1.6 g, more solvent is required to elute the phenanthrene compounds, and the eluted phenanthrene compounds also contain other impurities, resulting in unsatisfactory separation. Therefore, based on a crude oil usage of 50 mg, the inventors selected 1.4–1.6 g as the amount of MCM-41 molecular sieve added.

[0093] The foregoing description includes examples of one or more embodiments. It is certainly impossible to describe all possible combinations of components or methods in order to describe the above embodiments, but those skilled in the art will recognize that further combinations and arrangements of the various embodiments are possible. Therefore, the embodiments described herein are intended to cover all such changes, modifications, and variations that fall within the scope of the appended claims. Furthermore, the term "comprising" as used in the specification or claims is interpreted in a manner similar to the term "including," just as "comprising" is interpreted as a conjunction in the claims. Additionally, the use of any term "or" in the specification of the claims is intended to mean "non-exclusive or."

Claims

1. A method for separating phenanthrene compounds from a mixed aromatic hydrocarbon solution, characterized in that, Includes the following steps: A mixed aromatic solution was obtained by separating crude oil from it: the crude oil was dissolved in hexane, allowed to stand, and after the asphaltene precipitated, it was filtered to separate the mixed aromatic solution from the filtrate. Molecular sieve pretreatment: Dichloromethane was used as a solvent to extract the undemolded MCM-41 molecular sieve; Sample pretreatment: Add crude silica gel to a mixed aromatic hydrocarbon solution, evaporate the solvent, and obtain silica gel particles containing mixed aromatic hydrocarbons; Preparation of the chromatographic column: The extracted MCM-41 molecular sieve and the silica gel particles containing mixed aromatics were added sequentially into the chromatography column, and the MCM-41 molecular sieve and silica gel particles were compacted to obtain the chromatographic column. Sample separation: An organic solvent, namely n-hexane, is added to the chromatographic column to separate phenanthrene compounds.

2. The method according to claim 1, characterized in that, The crude oil has a mass fraction of 0.05 to 0.06 parts, and the extracted MCM-41 molecular sieve has a mass fraction of 1.4 to 1.6 parts.

3. The method according to claim 1, characterized in that, In the sample separation process, after adding an organic solvent to the chromatographic column, the process further includes: Nitrogen gas was introduced into the chromatographic column to pressurize it, and phenanthrene compounds were separated.

4. The method according to claim 1, characterized in that, The molecular sieve pretreatment also includes: the extraction time of the undemolded MCM-41 molecular sieve is 1.5 to 2 hours.

5. The method according to claim 1, characterized in that, The molecular sieve pretreatment also includes: extracting the undemolded MCM-41 molecular sieve using a Soxhlet extractor.

6. The method according to claim 1, characterized in that, In the sample pretreatment, the coarse silica gel has a mesh size of 80 to 100 mesh.

7. The application of the method for separating phenanthrene compounds from a mixed aromatic hydrocarbon solution according to any one of claims 1 to 6 in oil and gas exploration.

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