Method and device for separating carbazole compounds in light hydrocarbon oil

Abstract

The invention discloses a method and a device for separating carbazole compounds in light hydrocarbon oil, and belongs to the technical field of separation and purification. The separation method of the carbazole compounds in the light hydrocarbon oil comprises the following steps: mixing the light hydrocarbon oil with normal hexane, and then centrifuging to obtain top layer filtrate; transferring the filtrate into a chromatography device filled with activated neutral aluminum oxide, and then eluting saturated hydrocarbon fractions in the light hydrocarbon oil by using an n-hexane reagent; analyzing non-hydrocarbon fractions in the light hydrocarbon oil by using a mixed reagent of diethyl ether and dichloromethane; and eluting the carbazole compounds in the light hydrocarbon oil by using a mixed reagent of diethyl ether and dichloromethane. In addition, the invention further provides a separation device for the carbazole compounds in the light hydrocarbon oil, and the separation device comprises a storage rack, a beaker, a Pasteur pipette, a polytetrafluoroethylene tube and a funnel. The method provided by the invention is higher in experimental efficiency of separating and enriching carbazole compounds and better in separation effect.

Description

Technical Field

[0001] This invention relates to the field of separation and purification technology, specifically to a method and apparatus for separating carbazole compounds from light hydrocarbon oils. Background Technology

[0002] There are two main existing methods for separating carbazole compounds from crude oil: the two-step method and the C18 column method. Regardless of the method, the separation steps for carbazole compounds are relatively cumbersome, resulting in high compound loss and poor reproducibility. It is worth noting that for crude oils with extremely low carbazole content, such as condensate oil (or light oil), traditional methods are often too complex to separate carbazole compounds suitable for chromatographic mass spectrometry (GC-MS) detection.

[0003] Clearly, a faster and more efficient separation method and supporting experimental apparatus are needed for carbazole compounds in condensate oil (or light oil). Summary of the Invention

[0004] The improvement of this invention lies in the use of increased condensate oil (or light oil) and simplified separation steps, which, compared to the traditional two-step method, can increase the amount of carbazole compounds and concentrate them to meet the requirements of chromatographic mass spectrometry detection.

[0005] The purpose of this invention is to provide a method and apparatus for separating carbazole compounds from light hydrocarbon oils, thereby solving the technical problem of how to separate carbazole compounds more quickly and efficiently in the prior art.

[0006] To achieve the above-mentioned technical objectives, the present invention provides a method for separating carbazole compounds from light hydrocarbon oils, comprising the following steps: S1. Take light hydrocarbon oil and n-hexane, mix them, and then centrifuge to obtain the top filtrate; S2. The filtrate is transferred into a chromatography apparatus filled with activated neutral alumina, and then the saturated hydrocarbon fraction in the light hydrocarbon oil is eluted with n-hexane reagent. S3. Continue to elute the aromatic fraction in the light hydrocarbon oil with a mixture of n-hexane and dichloromethane. S4. Continue to elute the non-hydrocarbon fractions in the light hydrocarbon oil with a mixture of dichloromethane and methanol. S5. Continue to transfer the non-hydrocarbon fraction after solvent evaporation into a chromatography apparatus filled with activated silica gel, and fix the non-hydrocarbon fraction in the light hydrocarbon oil with n-hexane reagent. S6. Continue to use a mixture of diethyl ether and dichloromethane to analyze the non-hydrocarbon fractions in light hydrocarbon oils; S7. Continue eluting carbazole compounds from light hydrocarbon oils using a mixture of diethyl ether and dichloromethane.

[0007] In any embodiment, in step S3, the volume ratio of n-hexane to dichloromethane in the mixed reagent is 1:(2-2.5).

[0008] In any embodiment, in step S4, the volume ratio of dichloromethane to methanol in the mixed reagent is (8-9):1.

[0009] In any embodiment, in step S6, the volume ratio of diethyl ether to dichloromethane in the mixture of diethyl ether and dichloromethane is 8:(1.5-2).

[0010] In any embodiment, in step S7, the volume ratio of diethyl ether to dichloromethane in the mixture of diethyl ether and dichloromethane is 1:(0.9-1).

[0011] In any embodiment, in step S2, the activated neutral alumina is obtained by activating it by the following steps: treating the neutral alumina at 400-450°C for 4-5 hours.

[0012] In any embodiment, in step S5, the activated silicone is obtained by activating the silicone at 120-130°C for 7-8 hours.

[0013] In any embodiment, the light hydrocarbon oil is condensate oil or light oil.

[0014] Furthermore, the present invention also proposes a separation device for carbazole compounds in light hydrocarbon oils, comprising a shelf, a beaker, a Pasteur pipette, a polytetrafluoroethylene tube, and a funnel; the Pasteur pipette is connected to the lower part of the funnel, and the polytetrafluoroethylene tube is sleeved at the connection between the funnel and the Pasteur pipette; the bottom of the Pasteur pipette passes through the shelf and is placed on the shelf, and the beaker is located below the Pasteur pipette.

[0015] In any embodiment, a plurality of Pasteur pipettes are disposed on the shelf, each Pasteur pipette being provided with a corresponding funnel, a polytetrafluoroethylene tube, and a beaker; it also includes a silicone tube, a plurality of flow control switches, a flow controller, and a plurality of frosted stoppers; each frosted stopper is disposed at the top of the corresponding funnel, the silicone tube includes a plurality of branches, each branch being connected to the corresponding frosted stopper, and each branch being provided with a corresponding flow control switch.

[0016] Compared with the prior art, the beneficial effects of the present invention include: the present invention can quickly remove asphaltenes from crude oil using a centrifuge, and the neutral alumina chromatographic column can remove saturated hydrocarbons and aromatic components from crude oil and separate non-hydrocarbon compounds. Compared with the original method, this method has higher experimental efficiency and better separation effect for separating and enriching carbazole compounds. It has strong practical value for separation and identification when the content of carbazole compounds in light hydrocarbon oils is extremely low. Attached Figure Description

[0017] Figure 1 This is a schematic diagram of the structure of the separation device for carbazole compounds in light hydrocarbon crude oil according to Embodiment 1 of the present invention.

[0018] Figure 2 This is the total ion chromatogram (TIC) of the crude condensate before separation in Example 1 of the present invention.

[0019] Figure 3 This is the mass spectrum of carbazole compounds separated by a two-step method.

[0020] Figure 4 It is C 18 Mass spectra of carbazole compounds separated by column chromatography.

[0021] Figure 5 This is a mass spectrum of carbazole compounds separated by the method for separating carbazole compounds from light hydrocarbon oils proposed in Example 1 of this invention.

[0022] Figure 6 Selected ion monitoring chromatograms of carbazole compounds obtained by processing the crude oil sample of condensate oil in Example 1 of this application according to the method of Example 1 of the published patent document CN 112903872 A.

[0023] Figure 7 The selected ion monitoring chromatogram of carbazole compounds obtained from the separation of crude oil condensate sample by the separation method in Example 1 is shown.

[0024] Explanation of reference numerals in the attached diagram: 1-shelf, 2-beaker, 3-pasteurized pipette, 4-PTFE tube, 5-funnel, 6-frosted stopper, 7-silicone tube, 8-flow switch, 9-flow controller. Detailed Implementation

[0025] The "range" disclosed in this application is defined by a lower limit and an upper limit. A given range is defined by selecting a lower limit and an upper limit, which define the boundaries of a particular range. Ranges defined in this way can include or exclude endpoints and can be arbitrarily combined; that is, any lower limit can be combined with any upper limit to form a range. For example, if ranges of 60~120 and 80~110 are listed for a specific parameter, it is also expected that ranges of 60~110 and 80~120 are also included. Furthermore, if minimum range values ​​of 1 and 2 are listed, and if maximum range values ​​of 3, 4, and 5 are listed, then the following ranges are all expected: 1~3, 1~4, 1~5, 2~3, 2~4, and 2~5. In this application, unless otherwise stated, the numerical range "a~b" represents a shortened representation of any combination of real numbers between a and b, where a and b are real numbers. For example, the numerical range "0~5" indicates that all real numbers between "0~5" have been listed in this article; "0~5" is simply a shortened representation of these numerical combinations. Furthermore, when a parameter is stated as an integer greater than or equal to 2, it is equivalent to disclosing that the parameter is, for example, an integer such as 2, 3, 4, 5, 6, 7, 8, 9, 10, 11, 12, etc.

[0026] Unless otherwise specified, the terms "comprising" and "including" as used in this application can be open-ended or closed-ended. For example, "comprising" and "including" can mean that other components not listed may also be included, or that only the listed components may be included.

[0027] Unless otherwise specified, the term "or" is inclusive in this application. For example, the phrase "A or B" means "A, B, or both A and B". More specifically, the condition "A or B" is satisfied by any of the following conditions: A is true (or exists) and B is false (or does not exist); A is false (or does not exist) and B is true (or exists); or both A and B are true (or exist).

[0028] This specific embodiment provides a method for separating carbazole compounds from light hydrocarbon oils, including the following steps: S1. Mix light hydrocarbon oil and n-hexane, then centrifuge to obtain the top filtrate; remove asphaltene by rotation in a centrifuge. S2. The filtrate is transferred into a chromatography apparatus filled with activated neutral alumina, and then the saturated hydrocarbon fraction in the light hydrocarbon oil is eluted with n-hexane reagent. S3. Continue to elute the aromatic fraction in the light hydrocarbon oil with a mixture of n-hexane and dichloromethane; the volume ratio of n-hexane to dichloromethane in the mixture of n-hexane and dichloromethane is 1:(2-2.5). S4. Continue to elute the non-hydrocarbon fractions in the light hydrocarbon oil with a mixture of dichloromethane and methanol; the volume ratio of dichloromethane to methanol in the mixture of dichloromethane and methanol is (8-9):1. S5. Continue to transfer the non-hydrocarbon fraction after solvent evaporation into a chromatography apparatus filled with activated silica gel, and fix the non-hydrocarbon fraction in the light hydrocarbon oil with n-hexane reagent. S6. Continue to use a mixture of diethyl ether and dichloromethane to analyze the non-hydrocarbon fractions in the light hydrocarbon oil; the volume ratio of diethyl ether to dichloromethane in the mixture of diethyl ether and dichloromethane is 8:(1.5-2); S7. Continue to elute carbazole compounds in light hydrocarbon oils with a mixture of diethyl ether and dichloromethane; the volume ratio of diethyl ether to dichloromethane in the mixture is 1:(0.9-1).

[0029] In some embodiments, in step S2, the activated neutral alumina is obtained by activating the neutral alumina at 400-450°C for 4-5 hours; in step S5, the activated silica gel is obtained by activating the silica gel at 120-130°C for 7-8 hours.

[0030] In some embodiments, the light hydrocarbon oil is condensate oil or light oil.

[0031] Furthermore, this specific embodiment also proposes a separation device for carbazole compounds in light hydrocarbon oils, including a rack, a beaker, a Pasteur pipette, a polytetrafluoroethylene tube, and a funnel; the Pasteur pipette is connected to the lower part of the funnel, and the polytetrafluoroethylene tube is sleeved at the connection between the funnel and the Pasteur pipette; the bottom of the Pasteur pipette passes through the rack and is placed on the rack, and the beaker is located below the Pasteur pipette; the Pasteur pipette is filled with activated silica gel; the funnel is filled with activated neutral alumina.

[0032] In some embodiments, to simultaneously process multiple groups of light hydrocarbon oils, multiple Pasteur pipettes are disposed on the shelf, each Pasteur pipette having a corresponding funnel, a polytetrafluoroethylene tube, and a beaker; it also includes a silicone tube, multiple flow control switches, a flow controller, and multiple frosted stoppers; each frosted stopper is disposed at the top of the corresponding funnel, the silicone tube includes multiple branches, each branch is connected to the corresponding frosted stopper, and each branch is provided with a corresponding flow control switch; multiple funnels can simultaneously process light hydrocarbon oils.

[0033] To make the objectives, technical solutions, and advantages of this invention clearer, the invention will be further described in detail below with reference to the accompanying drawings and embodiments. It should be understood that the specific embodiments described herein are merely illustrative and not intended to limit the invention.

[0034] In this invention, the terms "some embodiments," "this embodiment," and examples are used to describe a subset of all possible embodiments. However, it is understood that "some embodiments" can be the same subset or different subsets of all possible embodiments and can be combined with each other without conflict.

[0035] If the application documents contain similar descriptions such as "first / second", the following explanation shall be added: In the following description, the terms "first / second / third" are used only to distinguish similar objects and do not represent a specific ordering of objects. It is understood that "first / second / third" may be interchanged in a specific order or sequence where permitted, so that the embodiments described herein can be implemented in an order other than that illustrated or described herein.

[0036] In this embodiment, the term "and / or" is merely a description of the relationship between related objects, indicating that there can be three relationships. For example, object A and / or object B can represent three situations: object A exists alone, object A and object B exist simultaneously, and object B exists alone.

[0037] The following describes embodiments of this application. The embodiments described below are exemplary and are only used to explain this application, and should not be construed as limiting this application. Where specific techniques or conditions are not specified in the embodiments, they are performed according to the techniques or conditions described in the literature in this field or according to the product instructions. Reagents or instruments used, unless otherwise specified, are all conventional products that can be obtained commercially.

[0038] Example 1 This embodiment proposes a method for separating carbazole compounds from light hydrocarbon oils, comprising the following steps: T1. Take an appropriate amount of crude oil sample into a centrifuge tube, add n-hexane, and centrifuge. Transfer the top layer filtrate from the centrifuge tube for later use. The centrifuge tube capacity is 15 mL, the weight of the condensate oil sample is 500 mg, and the volume of n-hexane added is 5 mL.

[0039] Specifically, the method to ensure sufficient precipitation of asphalt is to place the centrifuge tubes in a centrifuge at 5000 r / min for 15 min.

[0040] T2. Neutral alumina activated at 450°C for 4 hours is filled into the funnel of the matching chromatography apparatus (silica gel has not been filled into the matching chromatography apparatus before step T6). T3. Continue to transfer the filtrate in the centrifuge tube to the upper end of the matching chromatography apparatus filled with neutral alumina, and elute the saturated hydrocarbon fraction in the condensate oil (or light oil) with 15 mL of n-hexane reagent; elute the saturated hydrocarbon fraction with 15 mL of mixed solvent, with the reagent outflow rate at 1.0 mL / min, and the flow rate is controlled by a flow controller. T4. Continue to elute the aromatic fraction in the condensate oil with a mixture of 15 mL of hexane and dichloromethane (volume ratio of hexane to dichloromethane 1:2); add 15 mL of the mixed reagent to the chromatography column twice to elute the aromatic components. The effluent rate of the mixed reagent is 1.0 mL / min, and the flow rate is controlled using a flow controller. T5. Continue to elute the non-hydrocarbon fractions in the condensate oil with a mixture of 15 ml of dichloromethane and methanol (volume ratio of dichloromethane to methanol 9:1); the outflow rate of the mixed reagent is 1.0 mL / min, and the flow rate is controlled using a flow controller; T6. Continue to transfer the non-hydrocarbon fraction from the condensate oil after solvent evaporation to the upper part of the matching chromatography device filled with silica gel activated at 120°C for 8 hours. Fix the non-hydrocarbon fraction in the condensate oil with 10 ml of n-hexane reagent (starting from step T6, fill the matching chromatography device with silica gel and take out neutral alumina). T7. Continue to analyze the non-hydrocarbon fractions in the condensate oil using a mixture of 10 ml of diethyl ether and dichloromethane (volume ratio of diethyl ether to dichloromethane: 8:2); the outflow rate of the mixture is 0.5 mL / min, and the flow rate is controlled using a flow controller. T8. Continue to elute carbazole compounds in the condensate oil with a mixture of 10 ml of diethyl ether and dichloromethane (volume ratio of diethyl ether to dichloromethane is 1:1); the outflow rate of the mixed reagent is 0.5 mL / min, and the flow rate is controlled by a flow controller.

[0041] Combination Figure 1 This embodiment also proposes a separation device for carbazole compounds in light hydrocarbon oils, including a rack 1, 6 beakers 2, 6 Pasteur pipettes 6, 6 polytetrafluoroethylene tubes 4, and 6 funnels 5; each Pasteur pipette 6 is connected to the bottom of the corresponding funnel 5, and each polytetrafluoroethylene tube 4 is fitted at the connection between the corresponding funnel 5 and the corresponding Pasteur pipette 6; the bottom of each Pasteur pipette 6 passes through the rack 1 and is placed on the rack 1, and each beaker 2 is located below each Pasteur pipette 6; The separation device in this embodiment also includes a silica gel tube 7, six flow control switches 8, a flow controller 9, and six abrasive plugs 6. Each abrasive plug 6 is located at the top of the corresponding funnel 5. The silica gel tube 7 includes six branches, each branch connected to the corresponding abrasive plug 6, and each branch is equipped with a corresponding flow control switch. The Pasteur pipette is filled with activated silica gel. The funnel is filled with activated neutral alumina. The solvent enters the funnel through the silica gel tube from the abrasive plug, then flows through the Pasteur pipette, and finally flows out of the Pasteur pipette into a beaker. It should be noted that the activated neutral alumina is filled into the funnel before step T6, and from step T6 onwards, the neutral alumina is removed from the funnel, and the activated silica gel is filled into the Pasteur pipette. This embodiment can process six groups of crude oil samples simultaneously. In some embodiments, different numbers of raw material samples can be set as needed, such as five groups, eight groups, etc.

[0042] Specifically, the supporting silica gel chromatography apparatus consists of a Pasteur pipette, a PTFE tube, a small funnel, a ground glass stopper, a flow control switch, and a flow controller. The Pasteur pipette is 300 mm long with a 7 mm orifice, and is filled with 3 g of silica gel. The PTFE tube is 20 mm long with an 8 mm orifice. The small funnel has a 70 mm diameter, a 7 mm orifice at the bottom, and a 60 mm diameter ground glass stopper.

[0043] When the solvent needs to be changed, simply replace the solvent type connected to the flow control switch accordingly. In this embodiment, the Pasteur pipette is 300 mm long, has a 7 mm orifice, and is filled with 3 g of silica gel with a particle size of 60-200 μm. The PTFE tube is 20 mm long and has an 8 mm orifice. The small funnel has a diameter of 70 mm, a 7 mm orifice at the bottom, and a 60 mm diameter ground glass stopper.

[0044] Figure 2 The image shows the total ion chromatogram (TIC) of the crude oil sample. To verify the experimental effect of the portable column chromatography method for separating carbazole compounds in crude oil provided in this embodiment, the crude oil samples in this embodiment were subjected to a two-step method and a C24 chromatography method. 18 Carbazole compounds were separated using column chromatography and portable column chromatography, and then detected by GC-MS. The results are as follows: Figure 3-5 As shown in the mass chromatogram, the method proposed in this embodiment separates carbazole compounds with clearer peak distribution, higher signal intensity, and a detectable minimum concentration of 5 × 10⁻⁶. -6 mg / g corresponds to carbazole compounds such as carbazole, methylcarbazole, and dimethylcarbazole.

[0045] Combination Figure 6 and 7 It can be seen that the carbazole compounds obtained in Example 1 have a better separation effect than the separation method provided in the existing patent document CN112903872 A.

[0046] This embodiment uses a portable separation device composed of seven parts: a Pasteur pipette, a polytetrafluoroethylene tube, a funnel, a frosted stopper, a flow control switch, a silica gel tube, and a flow controller. A high-speed centrifuge is used to remove asphaltenes from the crude oil. A neutral alumina column is used to elute the enriched non-hydrocarbon fractions from the condensate (or light oil). 10 ml of n-hexane is used to fix the enriched non-hydrocarbons onto a silica gel column. 10 ml of diethyl ether / dichloromethane (8:2) reagent is used to analyze the non-hydrocarbon fractions in the condensate (or light oil), and 10 ml of diethyl ether / dichloromethane (1:1) reagent is used to elute carbazole compounds from the condensate (or light oil). This method is effective in separating and removing condensate (or light oil) with extremely low carbazole content, and the steps are simple, making it highly valuable for widespread application.

[0047] The specific embodiments of the present invention described above do not constitute a limitation on the scope of protection of the present invention. Any other corresponding changes and modifications made in accordance with the technical concept of the present invention should be included within the scope of protection of the claims of the present invention.

Claims

1. A method for separating carbazole compounds from light hydrocarbon oils, characterized in that, Includes the following steps: S1. Take light hydrocarbon oil and n-hexane, mix them, and then centrifuge to obtain the top filtrate; S2. The filtrate is transferred into a chromatography apparatus filled with activated neutral alumina, and then the saturated hydrocarbon fraction in the light hydrocarbon oil is eluted with n-hexane reagent. S3. Continue to elute the aromatic fraction in the light hydrocarbon oil with a mixture of n-hexane and dichloromethane. S4. Continue to elute the non-hydrocarbon fractions in the light hydrocarbon oil with a mixture of dichloromethane and methanol. S5. Continue to transfer the non-hydrocarbon fraction after solvent evaporation into a chromatography apparatus filled with activated silica gel, and fix the non-hydrocarbon fraction in the light hydrocarbon oil with n-hexane reagent. S6. Continue to use a mixture of diethyl ether and dichloromethane to analyze the non-hydrocarbon fractions in light hydrocarbon oils; S7. Continue eluting carbazole compounds from light hydrocarbon oils using a mixture of diethyl ether and dichloromethane.

2. The method for separating carbazole compounds from light hydrocarbon oils according to claim 1, characterized in that, In step S3, the volume ratio of n-hexane to dichloromethane in the mixed reagent is 1:(2-2.5).

3. The method for separating carbazole compounds from light hydrocarbon oils according to claim 1, characterized in that, In step S4, the volume ratio of dichloromethane to methanol in the mixed reagent is (8-9):

1.

4. The method for separating carbazole compounds from light hydrocarbon oils according to claim 1, characterized in that, In step S6, the volume ratio of diethyl ether to dichloromethane in the mixed reagent is 8:(1.5-2).

5. The method for separating carbazole compounds from light hydrocarbon oils according to claim 1, characterized in that, In step S7, the volume ratio of diethyl ether to dichloromethane in the mixed reagent is 1:(0.9-1).

6. The method for separating carbazole compounds from light hydrocarbon oils according to claim 1, characterized in that, In step S2, the activated neutral alumina is obtained by the following steps: treating the neutral alumina at 400-450℃ for 4-5 hours.

7. The method for separating carbazole compounds from light hydrocarbon oils according to claim 1, characterized in that, In step S5, the activated silicone is obtained by activating the silicone at 120-130°C for 7-8 hours.

8. The method for separating carbazole compounds from light hydrocarbon oils according to claim 1, characterized in that, The light hydrocarbon oil is condensate oil or light oil.

9. A device for separating carbazole compounds from light hydrocarbon oils, characterized in that, It includes a shelf, a beaker, a Pasteur pipette, a polytetrafluoroethylene tube, and a funnel; the Pasteur pipette is connected to the bottom of the funnel, and the polytetrafluoroethylene tube is fitted over the connection between the funnel and the Pasteur pipette. The bottom of the Pasteur pipette passes through the shelf and is placed on the shelf, with the beaker positioned below the Pasteur pipette.

10. The separation device according to claim 9, characterized in that, Multiple Pasteur pipettes are disposed on the shelf, each Pasteur pipette having a corresponding funnel, polytetrafluoroethylene tube and beaker; it also includes a silicone tube, multiple flow control switches, a flow controller and multiple frosted stoppers; each frosted stopper is disposed on the top of the corresponding funnel, the silicone tube includes multiple branches, each branch is connected to the corresponding frosted stopper, and each branch is provided with a corresponding flow control switch.

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