A method for quickly separating five components in crude oil using a silica gel column

Abstract

This application discloses a method for rapidly separating five components from crude oil using a silica gel column. The steps are as follows: separating asphaltenes from crude oil by centrifugation, eluting the saturated hydrocarbon fraction from the crude oil with n-hexane, eluting the aromatic hydrocarbon fraction with a mixed solvent of 80% n-hexane and 20% dichloromethane, eluting neutral nitrogen-containing compounds with a mixed reagent of 70% n-hexane and 30% ether, and eluting other polar components in non-hydrocarbons with a mixed reagent of 95% dichloromethane and 5% methanol. The present invention can rapidly separate asphaltenes from crude oil by centrifugation. Using a one-step method, the crude oil components adsorbed on the silica gel column can be sequentially released using mixed reagents of different polarities, rapidly obtaining the five components from the crude oil, and achieving good separation results for each component. Compared with existing separation methods, the present method is simple and rapid, and can simultaneously separate saturated hydrocarbons, aromatic hydrocarbons, non-hydrocarbons, and asphaltenes from crude oil group components while separating neutral nitrogen-containing compounds.

Description

Technical Field

[0001] The present application belongs to the technical field of separation and purification of neutral nitrogen-containing compounds in crude oil and separation of group components, and particularly relates to a method for rapidly separating five components in crude oil using a one-step method using a silica gel column. Background Art

[0002] Neutral nitrogen compounds are an important component of non-hydrocarbons. By studying the content and ratio characteristics of carbazole compounds, it has significant advantages in tracing oil and gas migration paths and tracing oil and gas source-reservoir information. There are two main methods for separating neutral nitrogen compounds. One is C 18 One-step column method, reported in the literature C 18 The one-step column method can achieve the separation and purification of nitrogen-containing compounds, but the content of the separated nitrogen-containing compounds is relatively low. For some samples with low nitrogen-containing compound content, the separation effect is poor. The other is the traditional nitrogen-containing compound separation method, which is mainly divided into two steps. The first step is to separate the non-hydrocarbon fraction as the main purpose, and the second step continues to separate the nitrogen-containing compounds on the basis of non-hydrocarbons. Although the two-step method has a good separation effect, the steps are cumbersome and an experiment lasts for 2-3 days, which greatly limits the separation efficiency of nitrogen-containing compounds. At the same time, due to the limitations of the experiment, the researchers had to carry out the separation of group components and the separation of nitrogen-containing compounds as two non-intersecting experiments. Obviously, the separation of nitrogen-containing compounds caused the waste of saturated hydrocarbons, aromatic hydrocarbons and non-hydrocarbon polar compounds. Summary of the Invention

[0003] In order to solve the technical problems of cumbersome separation steps of existing nitrogen-containing compounds and waste of saturated hydrocarbons, aromatic hydrocarbons and non-hydrocarbon fractions, the present application provides a method for quickly separating five components in crude oil using a silica gel column. The method combines the separation of neutral nitrogen-containing compounds with the traditional family component separation, thereby improving experimental efficiency.

[0004] The present invention is achieved by adopting the following technical solutions.

[0005] A method for quickly separating five components in crude oil using a silica gel column comprises the following steps:

[0006] S1. Add n-pentane to the crude oil sample to control the oil sample concentration to 6-8 mg / ml, and collect the filtrate by centrifugation to obtain asphaltene;

[0007] S2. The filtrate was transferred to the upper end of a chromatography device filled with silica gel, and the saturated hydrocarbon fraction in the crude oil was eluted with n-hexane;

[0008] S3. Use V 正己烷 :V 二氯甲烷 =8:2 mixed reagent to elute aromatic fractions from crude oil;

[0009] S4. Use V正己烷 :V 乙醚 =7:3 mixed reagent to elute neutral nitrogen compounds in crude oil;

[0010] S5. Use V 二氯甲烷 :V 甲醇＝ The 95:5 mixed reagent elutes the non-hydrocarbon polar components in crude oil.

[0011] Furthermore, in step S1, the centrifugation condition is 4000-4500 r / min for 5 minutes.

[0012] Furthermore, in step S2, the silica gel in the chromatography device is pre-activated at 100-120°C for 6-12 hours before filling.

[0013] Furthermore, in step S2, the particle size of the silica gel is 60-200 μm.

[0014] Furthermore, in step S2, the chromatography device includes a Pasteur pipette, a polytetrafluoroethylene tube, a funnel and a bracket; the funnel is connected to the upper end of the Pasteur pipette through the polytetrafluoroethylene tube, and the Pasteur pipette is placed on the bracket.

[0015] Furthermore, the length of the Pasteur pipette is 230 mm, the aperture is 7 mm, and the Pasteur pipette is filled with 3 g of silica gel; the length of the polytetrafluoroethylene tube is 10 mm, the aperture of the polytetrafluoroethylene tube is 8 mm; the diameter of the funnel pouring port is 50 mm, and the aperture of the funnel bottom is 7 mm.

[0016] Furthermore, in step S2, 5-8 mL of n-hexane is used to elute the saturated hydrocarbon fraction.

[0017] Furthermore, in step S3, 5-8 mL of a mixed reagent of n-hexane and dichloromethane is used to elute the aromatic fraction.

[0018] Furthermore, in step S4, the volume of the mixed reagent of n-hexane and diethyl ether is 1.4-1.8 times that of the filler, and the outflow rate of the mixed reagent is 1-1.5 mL / min.

[0019] Furthermore, in step S5, 5-8 mL of a mixed reagent of dichloromethane and methanol is used to elute the non-hydrocarbon polar components.

[0020] This application has the following beneficial effects.

[0021] This method rapidly separates asphaltenes from crude oil through centrifugation. Using a one-step process, crude oil components adsorbed on a silica gel column are sequentially released using a mixed reagent of varying polarity, rapidly obtaining the five components in the crude oil. This improves the efficiency of separating neutral nitrogen-containing compounds from group components. Compared to existing separation methods, the method is simpler and faster, and can simultaneously separate crude oil group components (saturated hydrocarbons, aromatic hydrocarbons, non-hydrocarbons, and asphaltenes) in addition to separating neutral nitrogen-containing compounds, demonstrating its significant practical and widespread application. BRIEF DESCRIPTION OF THE DRAWINGS

[0022] Figure 1 is the total ion current diagram of the saturated hydrocarbons separated by the present invention;

[0023] Figure 2 is the total ion current diagram of the aromatic hydrocarbons separated by the present invention;

[0024] Figure 3 This is the total ion current diagram of the nitrogen-containing compounds (carbazoles) separated by the present invention;

[0025] Figure 4 This is the mass chromatogram of the nitrogen-containing carbazole compound separated by the present invention (TIC, m / z167, m / z181, m / z195, m / z209);

[0026] Figure 5 It is a schematic structural diagram of the chromatography device of the present invention.

[0027] Among them, 1. Funnel; 2. Polytetrafluoroethylene tube; 3. Pasteur pipette; 4. Stand. DETAILED DESCRIPTION

[0028] The present patent application is further described below with reference to the embodiments.

[0029] Unless otherwise specified, the experimental methods used in the following examples are conventional methods; the materials, reagents, etc. used in the following preparation examples and examples are all commercially available unless otherwise specified.

[0030] A method for quickly separating five components in crude oil using a silica gel column comprises the following steps:

[0031] S1. Place 100 mg of crude oil sample in a 2 mL centrifuge tube, add 1.5 mL of n-pentane, and centrifuge at 4000 rpm for 5 minutes. Collect the top filtrate to obtain the asphaltenes.

[0032] S2. Activate the silica gel in a 120°C incubator for 12 hours and then fill it into the chromatography device;

[0033] Silica gel generally has a weaker adsorption capacity for components than neutral alumina of the same mesh size. Filling the chromatography apparatus with pure silica gel can improve the recovery rate of each component. In conventional operation, silica gel is activated in an insulated oven at 120°C for 12 hours and needs to be cooled before filling the chromatography apparatus. In this example, the activated silica gel is directly filled into the chromatography apparatus, which can improve the separation efficiency of neutral nitrogen-containing compounds.

[0034] Specifically, such as Figure 5 As shown, the chromatography device includes a Pasteur pipette 3, a polytetrafluoroethylene tube 2, a funnel 1, and a support 4. The funnel 1 is connected to the upper end of the Pasteur pipette 3 via the polytetrafluoroethylene tube 2, and the Pasteur pipette 3 is placed on the support 4. More specifically, the Pasteur pipette 3 is 230 mm long and has a pore size of 7 mm. The Pasteur pipette 3 is filled with 3 g of silica gel with a particle size of 16.9 μm. The polytetrafluoroethylene tube 2 is 10 mm long and has a pore size of 8 mm. The funnel 1 has a diameter of 50 mm and a pore size of 7 mm at the bottom of the funnel.

[0035] S3. The filtrate in the centrifuge tube was transferred to the upper end of a chromatography device filled with silica gel, and the saturated hydrocarbon fraction in the crude oil was eluted with 5 mL of n-hexane;

[0036] S4. Elute the aromatic fraction from the crude oil with 5 mL of a mixture of 80% n-hexane and 20% dichloromethane;

[0037] S5. eluting neutral nitrogen compounds from the crude oil with a mixture of 70% n-hexane and 30% ether;

[0038] Before eluting the nitrogen-containing compounds with a mixed reagent of n-hexane and ether, the silica gel column was dried for 10 min;

[0039] The volume of the mixed solution of n-hexane and ether used to elute the crude oil sample from which saturated hydrocarbons and aromatics were removed was 1.4 times that of the packing, and the elution rate of the mixed reagent was 1 mL / min;

[0040] S6. Use 5 mL of a mixture of 95% dichloromethane and 5% methanol to elute the non-hydrocarbon polar components in the crude oil.

[0041] In order to verify the experimental effect of the silica gel column one-step separation method provided by the present invention, each separated fraction was subjected to chromatographic-chromatographic detection. After step S5, the GC-MS total ion chromatogram (TIC) and mass chromatogram of selected ions (m / z167, m / z181, m / z195, m / z209) of the separated neutral nitrogen-containing compounds were measured. Figure 1-4It can be seen that the saturated hydrocarbon and aromatic hydrocarbon fractions have achieved complete elution of the compounds, and have a good separation effect on neutral nitrogen-containing compounds. The above results show that the method of the present invention can quickly separate the five commonly used components in crude oil.

[0042] The embodiments of this specific implementation method are all preferred embodiments of the present application and are not intended to limit the scope of protection of the present application. Therefore, any equivalent changes made based on the structure, shape, and principle of the present application should be included in the scope of protection of the present application.

Claims

1. A method for rapidly separating five components in crude oil using a silica gel column, characterized by: The following steps are involved: S1. Add n-pentane to the crude oil sample to control the oil sample concentration to 6-8 mg / ml, and collect the filtrate by centrifugation to obtain asphaltene; S2. The filtrate was transferred to the upper end of a chromatography device filled with silica gel, and the saturated hydrocarbon fraction in the crude oil was eluted with n-hexane; S3. Use V 正己烷 :V 二氯甲烷 =8:2 mixed reagent to elute aromatic fractions from crude oil; S4. Use V 正己烷 :V 乙醚 =7:3 mixed reagent to elute neutral nitrogen compounds in crude oil; S5. Use V 二氯甲烷 :V 甲醇 =95:5 mixed reagent to elute non-hydrocarbon polar components in crude oil.

2. The method for rapidly separating five components in crude oil using a silica gel column according to claim 1, characterized in that: In step S1, the centrifugation condition is 4000-4500 r / min for 5 min.

3. The method for rapidly separating five components in crude oil using a silica gel column according to claim 1, characterized in that: In step S2, the silica gel in the chromatography device is activated at 100-120°C for 6-12 hours before filling.

4. The method for rapidly separating five components in crude oil using a silica gel column according to claim 1, characterized in that: In step S2, the particle size of the silica gel is 60-200 μm.

5. The method for rapidly separating five components in crude oil using a silica gel column according to claim 1, characterized in that: In step S2, the chromatography device includes a Pasteur pipette, a polytetrafluoroethylene tube, a funnel and a bracket; the funnel is connected to the upper end of the Pasteur pipette through the polytetrafluoroethylene tube, and the Pasteur pipette is placed on the bracket.

6. The method for rapidly separating five components in crude oil using a silica gel column according to claim 1, characterized in that: In step S2, 5-8 mL of n-hexane is used to elute the saturated hydrocarbon fraction.

7. The method for rapidly separating five components in crude oil using a silica gel column according to claim 1, characterized in that: In step S3, 5-8 mL of a mixed reagent of n-hexane and dichloromethane is used to elute the aromatic fraction.

8. The method for rapidly separating five components in crude oil using a silica gel column according to claim 1, characterized in that: In step S4, the volume of the mixed reagent of n-hexane and diethyl ether is 1.4 to 1.8 times that of the filler, and the outflow rate of the mixed reagent is 1 to 1.5 mL / min.

9. The method for rapidly separating five components in crude oil using a silica gel column according to claim 1, characterized in that: In step S5, 5-8 mL of a mixed reagent of dichloromethane and methanol is used to elute the non-hydrocarbon polar components.

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