Amino carbon quantum dot crude oil flowability improver, and preparation method and application thereof

Abstract

The application discloses an amino carbon quantum dot crude oil flowability improver and a preparation method and application thereof, relates to the technical field of oil and gas exploitation aids, and aims to solve the defects of insufficient adaptability of existing crude oil medicaments. The preparation process comprises the following steps: pretreating biomass, and hydrothermally synthesizing amino carbon quantum dots by combining with an amine compound; subsequently, the amino carbon quantum dots are mixed with an initiator and a polymer monomer, and in-situ polymerization is performed to construct the amino carbon quantum dot crude oil flowability improver. The amino carbon quantum dot crude oil flowability improver has the advantages of green environmental protection and strong universality, and can significantly reduce the pour point and viscosity of high-condensation and high-viscosity crude oil, and improve the dispersion stability and adaptability of the medicament.

Description

Technical Field

[0001] This invention relates to the field of oil and gas extraction additives technology, specifically to an amino-carbon quantum dot crude oil flow improver, its preparation method, and its application. Background Technology

[0002] Petroleum is the lifeblood of industry, permeating our daily lives, and is an indispensable strategic resource for national security and development. In recent years, with the continuous increase in fossil fuel consumption, more and more oil fields are gradually shifting from conventional oil and gas resource extraction to unconventional resources, such as shale oil, shale gas, coalbed methane, high-wax crude oil, and heavy oil. High-wax crude oil is widely distributed throughout the world. More than 90% of my country's total crude oil production is high-wax crude oil. However, due to its high pour point, high viscosity, and poor low-temperature fluidity, it is prone to problems such as wax crystal precipitation, deposition, and pipeline blockage during extraction and transportation, severely restricting oilfield recovery and transportation efficiency. Heavy oil, due to its high viscosity caused by the presence of large amounts of gum and asphaltenes, affects its flow in formations and wellbores. Therefore, how to effectively improve the low-temperature fluidity of high-wax crude oil and heavy oil has become one of the key technical challenges in current oilfield development.

[0003] Currently, the mainstream technology for improving crude oil fluidity is the addition of chemical fluidity improvers. These improvers mainly reduce the pour point and viscosity of crude oil by interfering with the nucleation, growth, and aggregation processes of wax crystals, thereby altering the morphology of the wax crystals. In existing technologies, polymer-based improvers (such as acrylate copolymers and ethylene-vinyl acetate copolymers) and surfactant-based compound systems are widely used. Although polymer pour point depressants have played an important role in the past few decades, with the increasing complexity of extraction conditions and the continuous improvement of environmental protection requirements, a series of deep-seated technical contradictions have been exposed in their practical applications. Specifically, traditional polymer improvers generally face the problem of high "selectivity" towards crude oil components. Due to the significant differences in the wax composition, gum, and asphaltenes content of crude oil from different blocks, single-structure polymers often struggle to meet the pour point and viscosity reduction requirements of various oil products, resulting in poor universality. A deeper contradiction lies in the limitations of their physicochemical properties: traditional organic polymers often exhibit poor thermal and mechanical stability when facing extreme dynamic conditions such as high temperatures and high salinity in oil reservoirs. The agents are prone to degradation or deactivation, making it difficult to maintain long-term rheological improvement effects. Furthermore, while existing nanocomposite pour point depressants attempt to introduce inorganic components to enhance nucleation induction capabilities, they mostly employ simple physical blending methods, resulting in extremely poor interfacial compatibility between nanoparticles and the organic polymer matrix. This tendency towards "phase separation" at the microscopic level makes nanoparticles highly susceptible to secondary aggregation during storage and use. This not only fails to achieve the expected heterogeneous nucleation effect but may also become a new source of pipeline fouling due to particle deposition. Therefore, traditional flow improvers generally suffer from high sensitivity to crude oil composition and limited thermal stability, and some systems also suffer from high costs and poor environmental compatibility.

[0004] Carbon quantum dots (CQDs), as an emerging nanomaterial, possess characteristics such as small size, large specific surface area, abundant surface functional groups, ease of functionalization modification, good dispersibility, low toxicity, and good thermal stability. In recent years, CQDs have shown broad application prospects in catalysis, sensing, biomedicine, and energy. Of particular interest is the ability to introduce functional groups such as amino (-NH2), carboxyl (-COOH), and hydroxyl (-OH) groups onto their surface, endowing them with the ability to interact with gums, asphaltenes, and wax molecules in crude oil. Although existing research has explored the applications of carbon-based nanomaterials in oil displacement and corrosion inhibition, the application as a crude oil flow improver still faces the scientific challenge of how to organically couple nanoscale effects with the topological structure of macromolecular polymers. Existing technical approaches often fail to solve the problem of how to achieve synergistic effects between the functional groups on the carbon dot surface and the long polymer chains through strong chemical bonding rather than physical adsorption. If only carbon quantum dots are used as additives, due to their insufficient affinity with the organic components in crude oil, it is difficult to form an effective template effect in the early stage of wax crystal precipitation, and they lack the ability to deeply intervene in the aggregated state of gum and asphaltenes in crude oil.

[0005] In summary, current crude oil fluidity improvement technologies are at a bottleneck: on the one hand, it is necessary to overcome the inherent defects of traditional agents, such as poor stability and high selectivity; on the other hand, it is essential to solve the problem of high dispersion and long-term synergistic effect of nanomaterials in non-polar oil phase systems. Therefore, designing and preparing a novel improver that combines the advantages of heterogeneous nucleation of nanomaterials with the long-chain modification properties of polymers has become a key technological challenge that urgently needs to be overcome in the interdisciplinary field of petrochemicals and materials science. Summary of the Invention

[0006] This invention utilizes biomass resources as a carbon source to prepare carbon quantum dots with active amino groups on their surface through functionalization modification. Furthermore, these carbon quantum dots are used as core structural units to undergo in-situ polymerization with specific polymer monomers to construct an amino carbon quantum dot crude oil flow improver. This invention addresses the technical shortcomings of existing polymer-type crude oil flow improvers, such as poor adaptability to crude oil components in practical applications.

[0007] In a first aspect, the present invention provides a method for preparing an amino-carbon quantum dot crude oil flow improver, comprising the following steps: (1) The biomass is dried, crushed and sieved to obtain biomass powder; (2) Disperse biomass powder in a mixed solvent of ethanol / water to form a uniform suspension. Add amine compounds to the suspension while stirring, and then carry out a high-temperature reaction at 180~200℃ for 10~24h. After the high-temperature reaction, cool, filter, dialyze, and dry to obtain amino carbon quantum dots. (3) Disperse amino carbon quantum dots uniformly in a solvent, add polymer monomers containing unsaturated carbon and initiators, and carry out polymerization reaction in an inert protective atmosphere. After the reaction is completed, rotary evaporate and vacuum dry to obtain amino carbon quantum dot crude oil flow improver.

[0008] Preferably, the biomass in step (1) is at least one of sugarcane peel, sorghum stalk, cotton stalk, and corn stalk. Before drying, the biomass is rinsed multiple times to remove surface impurities. Vacuum drying is used for drying, and the biomass is crushed into powder using a pulverizer. The biomass powder collected after crushing is 100-300 mesh fine powder.

[0009] Preferably, the ethanol / water mixed solvent in step (2) is prepared by mixing ethanol and water in a volume ratio of 1:1, and the ratio of biomass powder to ethanol / water mixed solvent is 1.5~2.5 g / 100mL. The process of dispersing biomass powder in ethanol / water mixed solvent to form a uniform suspension is as follows: after adding biomass powder to the mixed solvent composed of ethanol and water, it is first dispersed by ultrasound. The power of the ultrasound dispersion is set to 100~300W and the ultrasound treatment time is 20~40min. Then, mechanical stirring is performed.

[0010] Preferably, the amine compound in step (2) is any one of dodecylamine, tetradecylamine, hexadecylamine, and octadecylamine, the mass ratio of the biomass powder to the amine compound is 0.5~2:0.5~2, the filtration is performed using a 0.22μm filter membrane, the dialysis is performed in a 1000Da dialysis bag for 24 hours, and the water is changed every 4 hours during the dialysis process.

[0011] Preferably, the high-temperature reaction in step (2) is carried out in a high-pressure hydrothermal reactor with a polytetrafluoroethylene liner.

[0012] Preferably, the polymer monomer in step (3) is any two of acrylamide, styrene, maleic anhydride, octadecyl methacrylate, and methacrylic acid, the solvent is toluene, the initiator is benzoyl peroxide, the polymerization reaction temperature is 80~90 ℃, and the reaction time is 5~8 h.

[0013] More preferably, the mass ratio of the two polymer monomers is 0.5~2:0.5~2, the mass ratio of each polymer monomer to amino carbon quantum dots is 8~15:1, and the initiator accounts for 0.5~2% of the total mass of the two polymer monomers.

[0014] Preferably, the inert protective gas in step (3) is nitrogen.

[0015] In a second aspect, the present invention provides an amino-carbon quantum dot crude oil flow improver prepared by the preparation method described in the first aspect.

[0016] Thirdly, this invention discloses the application of the amino carbon quantum dot crude oil flow improver described in the second aspect in petroleum production operations.

[0017] Compared with the prior art, the present invention has the following advantages and beneficial effects: 1. The crude oil fluidity improver provided by this invention has a highly scientific pharmaceutical structure design. It does not simply physically dope nanoparticles with polymers, but rather achieves deep integration of nano-carbon quantum dots and long chains of organic polymers through a two-step reaction of hydrothermal doping and in-situ polymerization under chemical bonding. This results in the construction of a chemically stable chemical bonding system. This structure completely solves the problem of sedimentation and agglomeration of nanoparticles in the oil phase system, thereby significantly improving the dispersion stability of the agent while effectively reducing the pour point and viscosity of high waxy crude oil.

[0018] 2. The raw materials used in the preparation of this invention are widely available and environmentally friendly. This invention uses agricultural and forestry biomass such as sugarcane peel and straw as the main raw materials, realizing the value-added utilization of waste resources. Compared with nano-modifiers using expensive graphene and carbon nanotubes as raw materials, the production cost of this invention is extremely low, and the solvents involved in the preparation process are mostly environmentally friendly media such as ethanol and water, which meets the requirements of green chemistry development.

[0019] 3. The crude oil flow improver provided by this invention possesses broad-spectrum and highly efficient pour point and viscosity reducing properties. Benefiting from the organic combination of the nano-effect of amino carbon quantum dots, the dispersion effect of polar groups, and the co-crystallization effect of polymer chains, this improver can effectively handle complex crude oil systems with different compositions and wax contents. Especially when dealing with high pour point, high viscosity, and extremely difficult-to-handle heavy and extra-heavy oils, this invention exhibits stronger adaptability and more significant cooling and flow-regulating capabilities than traditional polymers.

[0020] 4. The preparation process of the crude oil fluidity improver provided by this invention is mature and easy to industrialize. The hydrothermal synthesis, pressure filtration, rotary drying, and free radical polymerization involved in this invention are all highly mature unit operations in the chemical industry, with low equipment requirements, precise and controllable process parameters, and the ability to achieve large-scale standardized continuous production. Attached Figure Description

[0021] Figure 1 This is a low-magnification TEM image (scale bar 20 nm) of the amino-carbon quantum dots prepared in Example 1.

[0022] Figure 2 This is a high-magnification TEM image (scale bar 5 nm) of the amino-carbon quantum dots prepared in Example 1. Detailed Implementation

[0023] The present invention will be described in detail below with reference to specific embodiments and examples, thereby making the advantages and various effects of the present invention more clearly apparent. Those skilled in the art should understand that these specific embodiments and examples are for illustrative purposes only and are not intended to limit the present invention.

[0024] Throughout this specification, unless otherwise specified, the terminology used herein should be understood as having the meaning commonly used in the art. Therefore, unless otherwise defined, all technical and scientific terms used herein have the same meaning as commonly understood by one of ordinary skill in the art to which this invention pertains. In the event of any conflict, this specification shall prevail.

[0025] Unless otherwise specified, all raw materials, reagents, instruments and equipment used in this invention can be purchased from the market or prepared by existing methods.

[0026] Example 1 The preparation process of the amino-carbon quantum dot crude oil flow improver provided in this embodiment is as follows: (1) After washing the sugarcane peel residue with clean water, dry it in a vacuum oven at 90℃ for 12 hours. After drying, crush the sugarcane peel residue into powder using a pulverizer and filter it through a 200-mesh sieve. Collect the powder and put it in bags for later use. (2) Weigh 2g of biomass powder into 120mL of a 1:1 mixture of ethanol and water, dissolve by ultrasonic stirring, and then transfer the mixture into a hydrothermal reactor. While stirring, add 4g of dodecylamine. After reacting at 200℃ for 16h, cool to obtain a mixture. Filter the mixture through a 0.22μm filter membrane to obtain a clear liquid. Place the obtained clear liquid into a 1000Da dialysis bag for dialysis, changing the water every 4h. After dialysis for 24h, vacuum dry to obtain amino carbon quantum dots. The TEM image is shown below. Figure 1 , Figure 2 As shown, its size is in the nanometer range, and most of the amino carbon quantum dots have a relatively uniform particle size distribution between 2-5 nm, exhibiting good dispersibility, no obvious agglomeration, and a quasi-spherical morphology. (3) Add 40 mL of solvent toluene to a three-necked flask, then add 0.5 g of amino carbon quantum dots, 5 g of maleic anhydride, 5 g of octadecyl methacrylate, and 0.1 g of initiator benzoyl peroxide in sequence. Pass N2 through, stir magnetically in a water bath and heat to 85 °C. React for 7 h. After the reaction is complete, evaporate the toluene by rotary evaporation. The vacuum dried product is the amino carbon quantum dot crude oil flow improver.

[0027] Example 2 The preparation process of the amino-carbon quantum dot crude oil flow improver provided in this embodiment is as follows: (1) After washing the sorghum stalks with clean water, dry them in a vacuum oven at 80℃ for 12 hours. The dried sugarcane peel residue is crushed into powder by a pulverizer and filtered through a 200-mesh sieve. The powder is collected and bagged for later use. (2) Weigh 2g of biomass powder into 120mL of a 1:1 mixture of ethanol and water, dissolve by ultrasonic stirring, transfer the mixture into a hydrothermal reactor, and add 4g of dodecylamine while stirring. After reacting at 190℃ for 18h, cool to obtain a mixture. Filter the mixture through a 0.22μm filter membrane to obtain a clear liquid, and place the obtained clear liquid into a 1000Da dialysis bag for dialysis, changing the water every 4h. After dialysis for 24h, vacuum dry to obtain amino carbon quantum dots; (3) Add 40 mL of solvent toluene to a three-necked flask, then add 0.4 g of amino carbon quantum dots, 4 g of acrylamide, 4 g of octadecyl methacrylate, and 0.1 g of initiator benzoyl peroxide in sequence. Pass N2 through, stir magnetically in a water bath and heat to 90 °C. React for 6 h. After the reaction is complete, evaporate the toluene by rotary evaporation. The vacuum dried product is the amino carbon quantum dot crude oil flow improver.

[0028] Example 3 The preparation process of the amino-carbon quantum dot crude oil flow improver provided in this embodiment is as follows: (1) After washing the corn stalks with clean water, dry them in a vacuum oven at 70℃ for 12 hours. The dried sugarcane peel residue is crushed into powder by a pulverizer and filtered through a 200-mesh sieve. The powder is collected and bagged for later use. (2) Weigh 2g of biomass powder into 120mL of a 1:1 mixture of ethanol and water, dissolve by ultrasonic stirring, transfer the mixture into a hydrothermal reactor, and add 4g of dodecylamine while stirring. After reacting at 200℃ for 20h, cool to obtain a mixture. Filter the mixture through a 0.22μm filter membrane to obtain a clear liquid, and place the obtained clear liquid into a 1000Da dialysis bag for dialysis, changing the water every 4h. After dialysis for 24h, vacuum dry to obtain amino carbon quantum dots; (3) Add 40 mL of solvent toluene to a three-necked flask, then add 0.3 g of amino carbon quantum dots, 4 g of acrylamide, 5 g of methacrylic acid, and 0.1 g of initiator benzoyl peroxide in sequence. Pass N2 through, stir magnetically in a water bath and heat to 90 °C. React for 7 h. After the reaction is complete, evaporate the toluene by rotary evaporation. The vacuum dried product is the amino carbon quantum dot crude oil flow improver.

[0029] Example 4 The preparation process of the amino-carbon quantum dot crude oil flow improver provided in this embodiment is as follows: (1) After washing the cotton stalks with clean water, dry them in a vacuum oven at 90℃ for 12 hours. The dried sugarcane peel residue is crushed into powder by a pulverizer and filtered through a 200-mesh sieve. The powder is collected and bagged for later use. (2) Weigh 2g of biomass powder into 120mL of a 1:1 mixture of ethanol and water, dissolve by ultrasonic stirring, transfer the mixture into a hydrothermal reactor, and add 3g of dodecylamine while stirring. After reacting at 200℃ for 28h, cool to obtain a mixture. Filter the mixture through a 0.22μm filter membrane to obtain a clear liquid, and place the obtained clear liquid into a 1000Da dialysis bag for dialysis, changing the water every 4h. After dialysis for 24h, vacuum dry to obtain amino carbon quantum dots; (3) Add 40 mL of toluene solvent to a three-necked flask, then add 0.3 g of amino carbon quantum dots, 4 g of acrylamide, 4 g of styrene, and 0.15 g of initiator benzoyl peroxide in sequence. Pass N2 in, stir magnetically in a water bath and heat to 90 °C. React for 8 h. After the reaction is complete, evaporate the toluene by rotary evaporation. The vacuum dried product is the amino carbon quantum dot crude oil flow improver.

[0030] Comparative Example 1 Based on Example 1, this comparative example omits step (3) and does not add 4g of dodecylamine in step (2), directly using the carbon quantum dots prepared therefrom as crude oil fluidity improvers.

[0031] Comparative Example 2 Based on Example 1, this comparative example omits step (3) and directly uses the amino carbon quantum dots prepared in Example 1 as crude oil fluidity improvers.

[0032] To more clearly illustrate the technical solutions of the embodiments of the present invention, the effects of different addition amounts of the products prepared in Examples 1-4 and Comparative Examples 1-2 on the flowability of crude oil were evaluated, as shown in Table 1. High-pour-point and high-viscosity crude oils from the Jianghan Plain were selected to evaluate the effects of different addition amounts on the pour point and viscosity of the same crude oil. As shown in Table 2, the sample prepared in Example 1 was selected to evaluate its effects on the pour point and viscosity of different crude oils at different addition amounts. In this invention, the pour point of crude oil was determined using the national standard GB / T 510-2018 for testing the pour point of petroleum products, and the viscosity of crude oil was determined using SY / T0520-1993.

[0033] Table 1. Test results of pour point and viscosity of the same crude oil by different samples and different dosages.

[0034] Table 2 shows the test results of the samples prepared in Example 1 at different addition amounts for different crude oil pour points and viscosities.

[0035] As can be seen from the experimental data of Comparative Example 1 in Table 1, carbon quantum dots, as a nanomaterial, can provide a large number of nucleation sites for wax crystals due to their small size, good dispersibility, and large specific surface area, thus improving the fluidity of crude oil. The experimental data of Comparative Example 2 show that doping carbon quantum dots with long-chain amine compounds further improves the reduction of crude oil pour point viscosity. This is because, based on the improvement of crude oil fluidity caused by the small size of nanomaterials, amino carbon quantum dots further increase their adsorption on the oil-water surface, which can disperse the gums and asphaltenes in crude oil, reducing their adsorption and aggregation. In addition, they can also act as emulsifiers, changing the coating relationship between the oil and water phases in the oil-water mixture, thereby improving the fluidity of crude oil in pipeline transportation.

[0036] As can be seen from the experimental data in Examples 1-4, compared with amino carbon quantum dots, the amino carbon quantum dot crude oil flow improver obtained by coupling amino carbon quantum dots with polymers has superior pour point depressant and viscosity reduction properties for crude oil. Even a small amount can significantly change the state of the crude oil. When the pour point depressant dosage reaches 3000 mg / L or more, the crude oil pour point decreases from 31℃ to below 17℃, and the crude oil viscosity also decreases from 19947 mPa·s to approximately 600 mPa·s, achieving a viscosity reduction rate of 96.9%.

[0037] Various chemical groups, such as -OH, -COOH, and -NH2, doped onto amino carbon quantum dots are polymerized in situ with monomers to obtain a novel carbon dot polymer—amino carbon quantum dot crude oil flow improver. Because the nanoparticles are chemically bonded to the polymer, the organic modification is more complete, the dispersibility is increased, and the compatibility is stronger. It possesses advantages such as heterogeneous nucleation and electrostatic repulsion, as well as high dispersibility, good exfoliation performance, high long-term stability, and a more stable synergistic pour point depressant effect, greatly improving the low-temperature flowability of crude oil.

[0038] As can be seen from Table 2, the sample prepared in Example 1 has excellent pour point depressing and viscosity reducing properties for a variety of oils, and the effect is even better for some extra-thick oils.

[0039] Finally, it should be noted that the terms "comprising," "including," or any other variations are intended to cover a non-exclusive inclusion, such that a process, method, article, or apparatus that comprises a list of elements includes not only those elements but also other elements not expressly listed, or elements inherent to such a process, method, article, or apparatus. Although preferred embodiments of the invention have been described, those skilled in the art, upon learning the basic inventive concept, can make further changes and modifications to these embodiments. Therefore, the appended claims are intended to be interpreted as including both the preferred embodiments and all changes and modifications falling within the scope of the invention.

[0040] The embodiments described above merely illustrate specific implementation methods of this application, and while the descriptions are detailed and specific, they should not be construed as limiting the scope of protection of this application. It should be noted that those skilled in the art can make various modifications and improvements without departing from the concept of the technical solution of this application, and these modifications and improvements all fall within the scope of protection of this application.

Claims

1. A method for preparing an amino-carbon quantum dot crude oil flow improver, characterized in that, Includes the following steps: (1) The biomass is dried, crushed and sieved to obtain biomass powder; (2) Disperse biomass powder in a mixed solvent of ethanol / water to form a uniform suspension. Add amine compounds to the suspension while stirring, and then carry out a high-temperature reaction at 180~200℃ for 10~24h. After the high-temperature reaction, cool, filter, dialyze, and dry to obtain amino carbon quantum dots. (3) Disperse amino carbon quantum dots uniformly in a solvent, add polymer monomers containing unsaturated carbon and initiators, and carry out polymerization reaction in an inert protective atmosphere. After the reaction is completed, rotary evaporate and vacuum dry to obtain amino carbon quantum dot crude oil flow improver.

2. The preparation method according to claim 1, characterized in that, The biomass in step (1) is at least one of sugarcane peel, sorghum stalk, cotton stalk, and corn stalk. Before drying, the biomass is rinsed multiple times to remove surface impurities. Vacuum drying is used for drying, and the biomass is crushed into powder using a pulverizer. The biomass powder collected after crushing is 100-300 mesh fine powder.

3. The preparation method according to claim 1, characterized in that, The ethanol / water mixed solvent in step (2) is prepared by mixing ethanol and water in a volume ratio of 1:

1. The ratio of biomass powder to ethanol / water mixed solvent is 1.5~2.5g / 100mL. The process of dispersing biomass powder in ethanol / water mixed solvent to form a uniform suspension is as follows: after adding biomass powder to the mixed solvent composed of ethanol and water, it is first dispersed by ultrasound. The power of the ultrasound dispersion is set to 100~300W and the ultrasound treatment time is 20~40min. Then, mechanical stirring is performed.

4. The preparation method according to claim 1, characterized in that, The amine compound in step (2) is any one of dodecylamine, tetradecylamine, hexadecylamine, and octadecylamine. The mass ratio of the biomass powder to the amine compound is 0.5~2:0.5~2. The filtration is performed using a 0.22μm filter membrane. The dialysis is carried out in a 1000Da dialysis bag for 24 hours, and the water is changed every 4 hours during the dialysis process.

5. The preparation method according to claim 1, characterized in that, The high-temperature reaction in step (2) is carried out in a high-pressure hydrothermal reactor with a polytetrafluoroethylene liner.

6. The preparation method according to claim 1, characterized in that, The polymer monomer in step (3) is any two of acrylamide, styrene, maleic anhydride, octadecyl methacrylate, and methacrylic acid. The solvent is toluene, the initiator is benzoyl peroxide, the polymerization reaction temperature is 80~90 ℃, and the reaction time is 5~8 h.

7. The preparation method according to claim 6, characterized in that, The mass ratio of the two polymer monomers is 0.5~2:0.5~2, the mass ratio of each polymer monomer to amino carbon quantum dots is 8~15:1, and the initiator accounts for 0.5~2% of the total mass of the two polymer monomers.

8. The preparation method according to claim 1, characterized in that, The inert protective gas in step (3) is nitrogen.

9. The amino-carbon quantum dot crude oil flow improver prepared by the preparation method according to any one of claims 1 to 8.

10. The application of the amino-carbon quantum dot crude oil flow improver according to claim 9 in the production of high-pour-point crude oil and heavy oil with poor flowability.

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