Method for obtaining purified asphaltene secondary components from crude oil

Abstract

The invention belongs to the technical field of petroleum separation, and discloses a method for obtaining purified asphaltene secondary components from crude oil. The method comprises the following steps: firstly, fully dissolving a crude oil sample and a precipitate in a subsequent process in a solvent, then adding a precipitant into the solution to obtain a precipitation system, after the precipitation system is obtained, carrying out oscillation treatment on the precipitation system to obtain an oscillation liquid, and carrying out solid-liquid separation on the oscillation liquid to obtain a crude oil sample; the solid-liquid separation method is preferably centrifugal separation or filtration; after solid-liquid separation, liquid in a liquid phase is removed to obtain a soluble component, namely a secondary component, and then solvents and precipitants with different volume ratios are repeatedly added to separate out a plurality of asphaltene secondary components. Compared with a progressive precipitation asphaltene secondary component separation method, the method has the advantages that the precipitate is repeatedly and fully dissolved in the solvent, non-asphaltene components are released to the maximum extent, and the separated asphaltene secondary components are purer.

Description

Technical Field

[0001] The present invention belongs to the technical field of oil separation, and particularly relates to a method for obtaining purified asphaltene sub-components from crude oil. Background Art

[0002] In the field of petrochemical technology, for various purposes, it is necessary to separate multiple pure asphaltene sub-components from crude oil. For example, the Re-Os isochron (isotope model age and isochron) is established using multiple sub-components of a single crude oil for radioactive isotope dating research.

[0003] In traditional organic geochemistry research, crude oil can be separated into four group components: saturated hydrocarbons, aromatic hydrocarbons, non-hydrocarbons, and asphaltenes. Asphaltenes themselves are not a group component with uniform internal properties and can be further separated into multiple sub-components according to different solubility properties. Asphaltene molecules have the property of spontaneous aggregation, and multiple asphaltene molecules can form aggregates, flocculent structures, etc., and stably exist in crude oil. During geological processes such as gas invasion or the artificial separation of crude oil asphaltenes, asphaltene molecules can further form new and more aggregates, flocculent structures, etc. Non-asphaltene components such as saturated hydrocarbons, aromatic hydrocarbons, and non-hydrocarbons mainly exist in crude oil in the form of freely movable molecules, with some adsorbed on the surface of asphaltene aggregates and flocculent structures and some encapsulated inside the asphaltene structures. During natural or artificially induced asphaltene precipitation processes, the main component of the precipitate is asphaltene, and it also includes the original asphaltene structures, the non-asphaltene components encapsulated and adsorbed in the newly formed asphaltene structures, as well as the non-asphaltene components that co-precipitate under interaction.

[0004] At present, the method of obtaining asphaltene subcomponents is generally to separate crude oil asphaltene first and then use the progressive precipitation method to separate asphaltene subcomponents. Add an excess of precipitant, such as 40 times the volume of n-heptane, to the crude oil, and asphaltene can be obtained after oscillation and solid-liquid separation. This method can effectively manage the workload and meet the needs of some research. However, in this process, new and more asphaltene aggregates and flocculation structures can be further formed on the original basis, while encapsulating and adsorbing non-asphaltene components, and causing the co-precipitation of non-asphaltene components in other ways. Such non-asphaltene components may be difficult to be effectively removed in the later asphaltene purification process. Similarly, the separation of asphaltene subcomponents mainly depends on the binary solution composed of asphaltene precipitant and solvent, which is achieved by gradually providing the proportion of precipitant to promote the progressive precipitation of asphaltene. It is inevitable that non-asphaltene components exist in the subcomponents separated in the form of precipitation. In the process of separating asphaltene subcomponents using the progressive precipitation method, the proportion of the precipitant in the binary solution of the precipitant and the solvent gradually increases. In each step, the non-asphaltene components are promoted to be encapsulated and adsorbed into the aggregates and flocculation structures of asphaltene, and participate in the precipitation of asphaltene, so that the non-asphaltene is distributed in each asphaltene subcomponent.

[0005] However, in some studies, such as when using multiple asphaltene subcomponents for Re-Os radioisotope isochron dating, it is necessary to separate the asphaltene into multiple subcomponents and remove the co-precipitated and adsorbed non-asphaltene molecules as much as possible to eliminate their interference. The non-hydrocarbons in the non-asphaltene components also contain heteroatoms, polar functional groups and metal elements, including Re and Os. At the same time, non-asphaltene mainly exists in crude oil in the form of molecules that can move freely, and free molecules can also exchange with adsorbed molecules. Therefore, the properties of the free part and the adsorbed part of the non-asphaltene component may be uniform, including the Re-Os element content and isotope composition. Furthermore, the properties between the asphaltene subcomponents separated by the traditional progressive precipitation method may tend to be uniform under the influence of the non-asphaltene components. For example, the Re-Os element content and isotopic composition of the asphaltene subcomponents of a certain crude oil may be different, which can be used to establish Re-Os isochrones for dating; however, the asphaltene subcomponents separated by traditional methods may contain a large amount of non-hydrocarbons, and the non-hydrocarbons have consistent Re-Os element content and isotopic composition, which may make the Re-Os element content and isotopic composition between the asphaltene subcomponents tend to be uniform, and thus lose the ability to accurately and precisely date.

[0006] It can be seen that new methods need to be developed to obtain a series of relatively pure asphaltene sub-components from crude oil, so as to obtain the ability to accurately and precisely determine the age. Summary of the invention

[0007] The present invention aims to solve at least one of the technical problems existing in the above-mentioned prior art. To this end, the present invention provides a method for obtaining purified asphaltene sub-components from crude oil.

[0008] The method provided by the present invention will skip the step of separating asphaltenes from crude oil and use a progressive dissolution method opposite to the traditional progressive precipitation to directly separate multiple asphaltene sub-components from crude oil. The method of the present invention can obtain a series of pure asphaltene sub-components from crude oil.

[0009] The present invention provides a method for obtaining purified asphaltene sub-components from crude oil. The present invention fully dissolves crude oil in a solvent, then adds a precipitant, and separates out most of the free non-asphaltene components in the crude oil and the non-asphaltene components adsorbed in the flocculated and aggregated structures of some asphaltenes through oscillation and solid-liquid separation. Then, the precipitate after solid-liquid separation is fully dissolved in the solvent, and after fully releasing the non-asphaltene components adsorbed in the asphaltene structure, a precipitant is added, and the non-asphaltene components are removed through oscillation and solid-liquid separation. After that, the solvent ratio is gradually increased, and the dissolution, precipitation, oscillation, and solid-liquid separation of the precipitate are repeated to obtain multiple asphaltene sub-components. And, during this process, the non-asphaltene components are more enriched in the sub-components dissolved out earlier, and the non-asphaltene components such as non-hydrocarbons in the sub-components separated out later will be less and the asphaltenes will be purer.

[0010] Specifically, a method for obtaining purified asphaltene sub-components from crude oil includes the following steps:

[0011] (1) Dissolve a crude oil sample in a solvent, then add a precipitant to obtain a first precipitation system, and perform an oscillation treatment to obtain a first oscillating liquid;

[0012] (2) Perform solid-liquid separation on the first oscillating liquid, dissolve the obtained first precipitate in a solvent to obtain a first mixture;

[0013] (3) Then add a precipitant to the first mixture to obtain a second precipitation system;

[0014] (4) Perform an oscillation treatment on the second precipitation system to obtain a second oscillating liquid;

[0015] (5) Perform solid-liquid separation on the second oscillating liquid to obtain a second precipitate and a liquid phase, remove the liquid in the obtained liquid phase to obtain a soluble component, which is an asphaltene sub-component;

[0016] (6) Dissolve the second precipitate in a solvent, and in the obtained second mixture, the volume ratio of the solvent is further increased compared to the solvent ratio in the first mixture in step (3);

[0017] (7) Add a precipitating agent to the second mixture to obtain a third precipitation system, repeat the process of steps (4) to (5), and then separate out a sub-component of asphaltene;

[0018] (8) Repeat steps (6) to (7) to separate out multiple sub-components of asphaltene.

[0019] Preferably, in step (1), the solvent includes any one of dichloromethane, chloroform, carbon tetrachloride, toluene, and benzene; more preferably dichloromethane.

[0020] Preferably, in step (1), the precipitating agent includes any one of n-pentane, n-hexane, n-heptane, n-octane, petroleum ether, and acetone; more preferably n-heptane.

[0021] Preferably, in step (1), the time of the oscillation treatment is greater than 0 h. For example, it is 1 min to 16 h.

[0022] Preferably, the temperature of the oscillation treatment can be selected as room temperature or additional heating or cooling according to the experimental purpose; the room temperature is 20 - 25 °C.

[0023] In step (1), the dosage ratio of the crude oil to the solvent can be flexibly set according to the experimental purpose and the properties of the sample, preferably 1 g: 0.1 - 100 mL, more preferably 1 g: 1 - 10 mL, for example 1 g: 1 mL.

[0024] In step (1), the ratio of the crude oil to the precipitating agent can be flexibly set according to the experimental purpose and the properties of the sample, preferably 1 g: 0.1 - 100 mL, more preferably 1 g: 40 - 60 mL, for example 1 g: 40 mL.

[0025] In step (1), the initial dosage ratio of the precipitate to the solvent can be flexibly set according to the experimental purpose and the properties of the sample, preferably 1 g: 0.1 - 100 mL, more preferably 1 g: 10 - 20 mL; the initial volume ratio of the solvent to the precipitating agent is 10:90, 5:95, 1:99 and other ratios or other ratios more in line with the purpose, preferably 10:90; in the subsequent steps, the total volume of the solvent and the precipitating agent remains unchanged, or is adjusted to a variable total volume according to the experimental purpose; the proportion of the solvent in each step is increased by 10%, 5%, 1%, other ratios more in line with the purpose or variable ratios, preferably increased by 10% in each step.

[0026] Preferably, in step (2), the method of solid-liquid separation includes centrifugal separation or filtration.

[0027] Preferably, the rotation speed of the centrifugal separation > 0 revolutions per minute, and the centrifugal force ≥ 1 g.

[0028] Preferably, the rotation speed of the centrifugal separation is ≥ 1 revolution per minute, and more preferably 3500 - 4500 revolutions per minute.

[0029] Preferably, the centrifugal force of the centrifugal separation is ≥ 1g, and more preferably 1000 - 2000g.

[0030] Preferably, the time of the centrifugal separation is 0 min or more. For example, it is 10 min - 60 min.

[0031] Preferably, the pore size of the filter membrane used for filtration is 0.1 μm or more. For example, it is 0.1 - 0.5 μm.

[0032] Preferably, in step (5), the method for removing the liquid in the obtained liquid phase includes at least one of natural evaporation, heating evaporation, vacuum evaporation, pressure evaporation, and evaporation using a rotary evaporator.

[0033] The present invention utilizes the combination of a solvent and a precipitant for asphaltene, and realizes the multi - stage separation of asphaltene in crude oil by gradually increasing the solvent volume ratio and promoting progressive dissolution.

[0034] Before adding the precipitant, first fully dissolve the sample in the solvent; it can effectively release the non - asphaltene components from the asphaltene structure into the liquid phase and make them preferentially enriched in the sub - components separated earlier, while the asphaltene purity of the later sub - components is significantly improved.

[0035] Skip the traditional steps for separating asphaltene from crude oil, and directly start the sub - component separation from the crude oil sample, avoiding the introduction of new non - asphaltene components, which is beneficial to the purification of asphaltene and the protection of original geological information.

[0036] Preferably, the present invention provides a method for obtaining purified asphaltene sub - components from crude oil, including the following steps:

[0037] (1) Fully dissolve the crude oil sample in the solvent;

[0038] (2) Add a precipitant to the above solution to obtain a precipitation system;

[0039] (3) Oscillate the above precipitation system to obtain an oscillated liquid;

[0040] (4) Separate the solid phase and the liquid phase of the above oscillated liquid;

[0041] (5) Fully dissolve the precipitate obtained from the solid - liquid separation in step (4) in the solvent;

[0042] (6) Add a precipitant to the above solution to obtain a precipitation system;

[0043] (7) Oscillate the above precipitation system to obtain an oscillated liquid;

[0044] (8) Separate the above oscillating liquid into solid and liquid phases;

[0045] (9) Remove the liquid in the liquid phase to obtain the soluble components therein, which are one asphaltene sub-component;

[0046] (10) Dissolve the precipitate obtained from the solid-liquid separation in step (8) sufficiently in a solvent, with the solvent ratio increased compared to the previous step;

[0047] (11) Repeat steps (6) to (9) to separate out another asphaltene sub-component;

[0048] (12) Repeat steps (10) to (11) to separate out multiple asphaltene sub-components.

[0049] In the present invention, the crude oil sample and the precipitate in the subsequent process are first dissolved sufficiently in a solvent, and then a precipitant is added to the solution to obtain a precipitation system. After obtaining the precipitation system, the present invention subjects the precipitation system to oscillation treatment. After obtaining the oscillating liquid, the present invention separates the oscillating liquid into solid and liquid phases. The method of the solid-liquid separation is preferably centrifugal separation or filtration; after the solid-liquid separation, the present invention removes the liquid in the liquid phase to obtain the soluble components, which are one sub-component.

[0050] The method provided by the present invention avoids the introduction of non-asphaltene components in the forms of encapsulation, adsorption, and co-precipitation caused by the newly formed asphaltene aggregates and flocculation structures during the process by skipping the step of separating asphaltene from crude oil, especially the components that are present in the form of encapsulation and are difficult to remove in the later purification process. By first dissolving the sample in a solvent before adding the precipitant, the method provided by the present invention can fully deconstruct the flocculation structure of asphaltene, release more non-asphaltene components such as non-hydrocarbons present in the form of adsorption, etc., promote the preferential dissolution of non-asphaltene components and even easily soluble asphaltene components, and correspondingly make the asphaltene in the solid phase purer. By gradually increasing the ratio of the solvent, progressive dissolution is promoted to separate out more sub-components.

[0051] Application of the above method for obtaining purified asphaltene sub-components from crude oil in the petroleum field.

[0052] Compared with the prior art, the beneficial effects of the present invention are as follows:

[0053] Compared with other existing methods, the method of the present invention skips the step of separating asphaltenes from crude oil, avoiding the introduction of non-asphaltene components in the form of wrapping, adsorption, and coprecipitation caused by the newly formed asphaltene aggregates and flocculation structures during this process. Compared with the progressive precipitation method for separating asphaltene sub-components, the method of the present invention repeatedly dissolves the precipitate sufficiently in the solvent to maximize the release of non-asphaltene components, making the separated asphaltene sub-components (especially the later-separated asphaltene sub-components) purer, and providing assistance for organic geochemical research such as the molecular structure, behavior, and characteristic compounds of asphaltenes, as well as elemental and isotope research in oil and gas geochemistry research and petroleum production.

[0054] The method of the present invention realizes the controllability of the separation process through the regulation of the solvent ratio gradient, and has the advantages of simple operation and high separation efficiency. Detailed implementation manners

[0055] In order to make those skilled in the art more clearly understand the technical solutions of the present invention, the following examples are listed for illustration. It should be noted that the following examples do not limit the scope of protection required by the present invention.

[0056] The raw materials, reagents or devices used in the following examples can be obtained from conventional commercial channels or can be obtained by existing known methods without special instructions.

[0057] The method provided by the present invention skips the step of separating asphaltenes from crude oil, avoiding the introduction of non-asphaltene components in the form of wrapping, adsorption, and coprecipitation caused by the newly formed asphaltene aggregates and flocculation structures during this process, especially the components that exist in the form of wrapping and are difficult to remove during the later purification process. The method provided by the present invention first dissolves the crude oil sample in the solvent before adding the precipitant, which can fully decompose the flocculation structure of asphaltenes, release more non-asphaltene components such as non-hydrocarbons existing in the form of adsorption, promote the preferential dissolution of non-asphaltene components and even easily soluble asphaltene components, and correspondingly make the asphaltenes in the solid phase purer. By gradually increasing the proportion of the solvent, progressive dissolution is promoted to separate more asphaltene sub-components.

[0058] The asphaltene sub-components separated according to the method provided by the present invention can be subjected to subsequent experiments as needed, and the present invention does not make specific limitations.

[0059] Next, the technical solutions in the present invention will be clearly and completely described in combination with the examples in the present invention.

[0060] In a specific embodiment of the present invention, the amount of crude oil sample used is preferably ≥20 g; the solvent is preferably dichloromethane, and the precipitant is preferably n-heptane; the dosage ratio of crude oil to solvent is preferably 1 g:1 mL; the ratio of crude oil to precipitant is 1 g:40 mL; the starting ratio of precipitate to solvent is 1 g:10 mL; the starting volume ratio of solvent to precipitant is 10:90; in each subsequent step, the total volume of the solvent and the precipitant remains unchanged, and the proportion of the solvent in each step is increased by 10%. The separation step is repeated until the proportion of the precipitant in the binary solution drops to 0.

[0061] The oscillation treatment conditions of the precipitation system are 16 h at room temperature; the solid-liquid separation method is centrifugation, centrifuging at a speed of 4500 revolutions per minute (about 1800 g) for 15 minutes; the method for removing the liquid in the liquid phase is evaporation using a rotary evaporator. The soluble components in the liquid phase collected in each step are a sub-component.

[0062] Example 1

[0063] Taking the crude oil sample from the Upper Cretaceous Cenomanian carbonate reservoir in the Persian Gulf as the research object, the purified asphaltene sub-components are obtained from the crude oil sample by the method of the present invention. The specific process is as follows:

[0064] Weigh 41.0167 g of crude oil, place it in a 2 L glass bottle, and completely dissolve it in 40 mL of dichloromethane. Then add 1600 mL of n-heptane and mix well to obtain a precipitation system (Table 1). Place the glass bottle in a shaker and oscillate it at room temperature (about 20 °C) for 16 hours. Pour the oscillated liquid into a centrifuge tube and centrifuge it at a speed of 4500 revolutions per minute (>1000 g) for 15 minutes to separate the solid phase (precipitate) and the liquid phase. Use a rotary evaporator to remove the liquid (solvent and precipitant) in the liquid phase to obtain the soluble components therein; collect the precipitate and the soluble components into 22 mL glass bottles respectively with dichloromethane, and then evaporate the dichloromethane to dryness at 35 °C and weigh. In this step, 2.1352 g of precipitate and 39.2241 g of soluble components can be obtained, accounting for 5.2% and 95.6% of the crude oil mass respectively, and the total recovery rate is 100.8%. It is possible that some solvents are not completely evaporated;

[0065] The precipitate was transferred to a 250 mL round-bottom flask and fully dissolved in 20 mL of dichloromethane. n-heptane was added to the solution at a ratio of 10:90 between the solvent and the precipitant, i.e., 180 mL of n-heptane, to obtain a precipitation system (Table 1). The total volume of the solvent and the precipitant was 200 mL. The glass bottle was placed in a shaker and shaken at room temperature (about 20°C) for 16 hours. The shaken liquid was poured into a centrifuge tube and centrifuged at 4500 rpm (>1000 g) for 15 minutes to separate the solid phase (precipitate) and the liquid phase. A rotary evaporator was used to remove the liquid (solvent and precipitant) in the liquid phase to obtain the soluble components therein. The precipitate and the soluble components were collected in a 250 mL round-bottom flask and a 22 mL glass bottle respectively with dichloromethane, and then the dichloromethane was evaporated at 35°C to dryness, and the mass of the soluble components was weighed.

[0066] The above steps of transferring the precipitate to a round-bottom flask, dissolving in a solvent, adding a precipitant, shaking, solid-liquid separation, sample collection and weighing were repeated until the solvent ratio reached 100% (Table 1). In each repeated process, the total volume of the solvent (dichloromethane) and the precipitant (n-heptane) was determined to be 200 mL, and the solvent was gradually increased and the precipitant was reduced by 10%.

[0067] This process was repeated to obtain 10 soluble components and 1 precipitation component in the last step, a total of 11 components, of which the last 10 were mainly asphaltene and can be called asphaltene subcomponents (Table 1).

[0068] The initial sample dosage was 41.0167 g, and a total of 41.3549 g was recovered, which basically reached mass balance (100.8%; some reagents in the first soluble component may not be evaporated to dryness).

[0069] Table 1: Example 1 Separation of crude oil asphaltene subcomponents

[0070]

[0071]

[0072] Comparative Example 1

[0073] Similarly, a crude oil sample from the Cenomanian carbonate reservoir of the Upper Cretaceous in the Persian Gulf was used as a research object, and a method different from the method of the present invention was adopted to first separate the crude oil asphaltene, and then separate the asphaltene subcomponents by a progressive precipitation method.

[0074] The specific contents of Comparative Example 1 are as follows:

[0075] First, use n-heptane to separate the asphaltene of crude oil: weigh 41.8526g of crude oil, put it in a 2L glass bottle, add 1600mL of n-heptane, mix thoroughly to obtain a precipitation system, put the glass bottle into a shaker, shake it at room temperature (about 20°C) for 16 hours, pour the shaking liquid into a centrifuge tube, centrifuge it at 4500 rpm (>1000g) for 15 minutes to separate the solid phase (precipitate) and the liquid phase. Use a rotary evaporator to remove the reagents (solvent and precipitant) in the liquid phase to obtain the soluble components; use dichloromethane to collect the precipitate and soluble components respectively, then evaporate the dichloromethane at 35°C and weigh;

[0076] This step yielded 2.3856 g of precipitate and 40.1366 g of soluble components, accounting for 5.7% and 95.9% of the crude oil, respectively, with a total recovery rate of 101.6%. Some of the solvent in the soluble components may not have been completely evaporated. It can be seen that the proportion of the first step precipitation in Example 1 of the method of the present invention (5.2%) is significantly lower than the asphaltene obtained by the traditional method (5.7%), indicating that the solvent has a significant effect on the removal of non-asphaltene components.

[0077] Subsequently, the asphaltenes were separated into multiple subcomponents by progressive precipitation: the precipitant and solvent combination of n-heptane and dichloromethane was also used, and the total volume was maintained at 200 mL; different from Example 1, starting from a volume ratio of solvent to precipitant of 90:10, the proportion of precipitant was increased by 10% in each step.

[0078] In the specific operation, the asphaltene was first transferred to a 250 mL round-bottom flask and fully dissolved in 180 mL of dichloromethane. n-heptane, i.e., 20 mL of n-heptane, was added in a predetermined ratio to obtain a precipitation system (Table 2). The glass bottle was placed in a shaker and shaken at room temperature (about 20°C) for 16 hours. The shaken solution was poured into a centrifuge tube and centrifuged at 4500 rpm (>1000 g) for 15 minutes to separate the solid phase (precipitate) and the liquid phase. However, no precipitation was produced at this ratio of solvent to precipitant. The solution was poured back into the round-bottom flask and the reagent was removed using a rotary evaporator. The sample in the round-bottom flask was repeatedly dissolved in the solvent, added with a precipitant, shaken, separated solid and liquid, collected and weighed. The precipitant ratio was increased by 10%. This was repeated until the precipitant accounted for 70%, at which time precipitation appeared for the first time. The precipitate was an asphaltene subcomponent.

[0079] Use a rotary evaporator to remove the liquid (solvent and precipitant) in the liquid phase to obtain the soluble components; use dichloromethane to collect the precipitate and soluble components in a 22 mL glass bottle and a 250 mL round-bottom flask, respectively, and then evaporate the dichloromethane at 35 ° C, and weigh the precipitate;

[0080] According to the established steps and ratios, solvents and precipitants were added to the soluble part in a round-bottom flask, followed by shaking, solid-liquid separation, collecting the precipitate, and rotary evaporation of the reagents in the liquid phase. This was repeated until the precipitant ratio reached 100% (Table 2), which was the last step. At the end of the experiment, a total of 4 precipitates and 1 soluble component in the last step, etc., a total of 5 sub-components of asphaltenes were obtained (Table 2).

[0081] The initial sample amount was 41.8526 g, and a total of 42.5242 g was recovered, basically achieving mass balance (101.6%; there may be some reagents not completely evaporated in the separated asphaltenes and the soluble component in the last step, and there may be some sample losses during the operation process).

[0082] Compared with Example 1, the method used in Comparative Example 1 could separate out significantly fewer sub-components, and the mass of each sub-component or its proportion in the crude oil was also higher. The higher percentage of sub-components in Comparative Example 1 was, on the one hand, the result of fewer sub-components, and on the other hand, the result of more non-asphaltene components adsorbed, wrapped, and co-precipitated during the separation process of its sub-components than in Example 1. Among them, the sum of the 4 precipitate sub-components in Comparative Example 1 (5.3%) was higher than the percentage of the precipitate separated from the crude oil in Example 1 (5.2%). In addition, the sub-component that remained dissolved in 100% pure precipitant in the end in Comparative Example 1 reached 0.1639 g, accounting for 0.4%, and a considerable part was non-hydrocarbon and other non-asphaltene components.

[0083] Table 2: Separation of Sub-components of Crude Oil Asphaltenes in Comparative Example 1

[0084]

[0085] The above are only the preferred embodiments of the present invention. It should be noted that for those of ordinary skill in the art, without departing from the principle of the present invention, several improvements and refinements can be made, and these improvements and refinements should also be regarded as the protection scope of the present invention.

Claims

1. A method for obtaining purified asphaltene subcomponents from crude oil, characterized in that: The following steps are involved: (1) dissolving a crude oil sample in a solvent, then adding a precipitant to obtain a first precipitation system, and performing an oscillation treatment to obtain a first oscillation liquid; (2) performing solid-liquid separation on the first oscillated liquid, dissolving the obtained first precipitate in a solvent, and obtaining a first mixture; (3) then adding a precipitant to the first mixture to obtain a second precipitation system; (4) shaking the second precipitation system to obtain a second shaking liquid; (5) subjecting the second oscillated liquid to solid-liquid separation to obtain a second precipitate and a liquid phase, and removing the liquid in the obtained liquid phase to obtain a soluble component, i.e., an asphaltene subcomponent; (6) dissolving the second precipitate in a solvent, wherein the volume of the solvent in the obtained second mixture is further increased compared with the proportion of the solvent in the first mixture in step (3); (7) adding a precipitant to the second mixture to obtain a third precipitation system, repeating the process from step (4) to step (5) to separate another asphaltene subcomponent; (8) Repeat steps (6) to (7) to separate multiple asphaltene subcomponents.

2. The method according to claim 1, characterized in that In step (1), the solvent includes any one of dichloromethane, chloroform, tetrachloromethane, toluene and benzene.

3. The method according to claim 1, characterized in that In step (1), the precipitant includes any one of n-pentane, n-hexane, n-heptane, n-octane, petroleum ether and acetone.

4. The method according to claim 1, characterized in that: In step (1), the oscillation treatment time is greater than 0 h.

5. The method according to claim 1, characterized in that: In step (1), the usage ratio of the crude oil to the solvent is 1 g: 0.1 to 100 mL.

6. The method according to claim 1, characterized in that In step (1), the ratio of the crude oil to the precipitant is 1 g: 0.1 to 100 mL.

7. The method according to any one of claims 1 to 6, characterized in that: In step (1), the initial dosage ratio of the precipitate to the solvent is 1 g: 0.1 to 100 mL.

8. The method according to claim 7, characterized in that In step (2), the solid-liquid separation method includes centrifugal separation or filtration.

9. The method according to claim 7, characterized in that: In step (5), the method for removing the liquid in the obtained liquid phase includes at least one of natural evaporation, heating evaporation, reduced pressure evaporation, pressurized evaporation, and rotary evaporator evaporation.

10. Application of the method according to any one of claims 1 to 9 in the petroleum field.

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