Novel crude oil pour point depressant and preparation method thereof

Abstract

The invention provides a novel crude oil pour point depressant and a preparation method thereof, and relates to the technical field of pour point depressants. The novel crude oil pour point depressant comprises 3%-10% of an organic nano-material, 2%-8% of an inorganic dopant, 70%-85% of a polymer pour point depressant, 2-5% of a low-temperature flow improver, 1%-5% of a cross-linking agent and 0.5%-8% of an ionic stabilizer, and the organic nano-material is lignin nanospheres or cellulose nanocrystals. The novel crude oil pour point depressant is high in hydrothermal stability, good in salt tolerance and high in mechanical strength through synergistic cooperation of the organic nanomaterial, the inorganic dopant, the polymer pour point depressant, the low-temperature flow improver, the cross-linking agent and the ionic stabilizer, and meanwhile, the product can be used at low temperature.

Description

TECHNICAL FIELD

[0001] The present application relates to the technical field of pour point depressant, in particular to a novel crude oil pour point depressant and a preparation method thereof. BACKGROUND

[0002] Generally, crude oil contains liquid wax, petroleum wax, paraffin wax and microcrystalline wax, among which paraffin wax and microcrystalline wax have the greatest impact. Normal paraffin is the main component, and the content of aromatic hydrocarbon is very small. In addition, the average molecular weight of paraffin hydrocarbon is 300-450, and the number of carbon atoms is mostly C17-C35. The number of carbon atoms of microcrystalline wax obtained by deoiling and refining from petroleum vacuum residue is 30-60. The pour point of waxy crude oil is relatively high, which makes the mining and gathering and transportation of this part of crude oil particularly prominent. The main technologies to improve the flowability of crude oil include heating method, dilution method, emulsification method and pour point depressant method, etc. For high pour point waxy crude oil after dehydration, heating or adding pour point depressant is mainly used to ensure normal transportation. For heating transportation, a heating station is set up every tens of kilometers on the pipeline. The disadvantages are high energy consumption, small allowable transportation capacity range, and no safety guarantee. If the pipeline is stopped for a long time, the crude oil will be cooled to condensation, which will cause disastrous consequences of pipeline blockage. From the perspective of reducing energy consumption and production cost and improving the safety of pipeline operation, adding pour point depressant to crude oil to reduce the pour point of crude oil and improve its low-temperature flowability is an effective way to improve the mining and transportation process of high pour point and high viscosity crude oil, and is also the simplest and most effective method to realize the transportation of crude oil at room temperature or even low temperature. In particular, the research on pour point depressant for long-distance pipeline transportation is also very mature.

[0003] In recent years, inorganic micro-nano particles have been applied to polymer pour point depressant systems to prepare new polymer / inorganic micro-nano composite pour point depressant. It has been found that the composite pour point depressant particles dispersed in the oil phase can act as a wax crystal template to promote the formation of wax crystal floc with large size and compact structure, thereby further improving the rheological properties of waxy crude oil. However, inorganic micro-nano particles have poor organic compatibility, poor salt resistance (mineralization degree greater than 5% will cause failure), and unstable pour point depressant effect, which will bring potential adverse effects to the subsequent treatment process of waxy crude oil and restrict the development and application of inorganic micro-nano composite pour point depressant.

[0004] In addition, there is a huge market demand for pour point depressants that can be used at low temperatures or even extremely low temperatures. In high-yield oil fields in countries such as Russia, Canada and the United States, most of the oil fields are in cold regions. Under the extreme conditions of winter, the conventional pour point depressants on the market will all become solids, so oil companies are forced to stop using pour point depressants in winter and instead use high-cost mechanical scraping or regular cleaning of oil production pipes with hot solvents, which greatly limits the efficiency of crude oil production. Therefore, there is a huge demand for pour point depressants that can be used at low temperatures in this market. SUMMARY

[0005] To solve the above problems, the application provides a new crude oil pour point depressant. The new crude oil pour point depressant is based on a polymer pour point depressant, and has the mechanical property and pour point depression effect enhanced by adding organic nanomaterials, the hydrothermal stability and salt tolerance improved by adding inorganic dopants, the compatibility between raw materials improved by adding a crosslinking agent, and the salt tolerance improved by adding an ionic stabilizer. The low-temperature fluidity is improved by adding a low-temperature flow improver. The new crude oil pour point depressant has high hydrothermal stability, good salt tolerance, high mechanical strength, and good pour point depression effect, and has good low-temperature characteristics and can be used at low temperature.

[0006] The application provides a new crude oil pour point depressant. The new crude oil pour point depressant comprises 3-10% of organic nanomaterials, 2-8% of inorganic dopants, 70-85% of a polymer pour point depressant, 2-5% of a low-temperature flow improver, 1-5% of a crosslinking agent, and 0.5-8% of an ionic stabilizer.

[0007] Optionally, the new crude oil pour point depressant comprises 4-6% of organic nanomaterials, 3-5% of inorganic dopants, 75-80% of a polymer pour point depressant, 3-4% of a low-temperature flow improver, 2-3% of a crosslinking agent, and 2-6% of an ionic stabilizer.

[0008] Optionally, the particle size of the organic nanomaterials is less than 50 nm. The nanoscale dispersion can provide nucleation sites and induce heterogeneous crystallization of wax crystals.

[0009] Optionally, the particle size of the inorganic dopants is 50-100 nm.

[0010] Optionally, the lignin nanospheres are subjected to modification treatment, and the modification treatment comprises the following steps.

[0011] The lignin nanospheres are added into an alkali solution, and a silane coupling agent is added to perform reaction, to obtain silanized lignin nanospheres. The silanized lignin nanospheres are added into a polyethylene glycol solution to perform reaction, to obtain modified lignin nanospheres.

[0012] The lignin nanospheres have hydrophobicity, and may be phase-separated from the ionic stabilizer, and have compatibility problems. The lignin nanospheres are subjected to modification treatment, and are subjected to hydrophobic treatment by a silane coupling agent and grafting of a polyethylene glycol hydrophilic chain segment, to further improve the compatibility of the lignin nanospheres and ensure the stability and pour point depression effect of the pour point depressant.

[0013] Optionally, the pH of the alkali solution is greater than 10. For example, the alkali solution can be a sodium hydroxide solution with a pH of 10. However, the application is not limited thereto.

[0014] Optionally, the silane coupling agent is one or more of gamma-methacryloxypropyltrimethoxysilane (KH-570), gamma-mercaptopropyltrimethoxysilane (KH-590), and gamma-aminopropyltriethoxysilane (KH-550).

[0015] Optionally, the mass ratio of the silane coupling agent to the lignin nanospheres is 5%-12%, and the mass ratio of the polyethylene glycol to the lignin nanospheres is 20%-35%. During the modification of the lignin nanospheres, the amount of the silane coupling agent is controlled to ensure that the surface hydroxyl coverage of the lignin nanospheres is more than 60%, and the amount of the polyethylene glycol is controlled to avoid the formation of a too-thick hydrophilic layer that hinders the physical entanglement with the polymer pour point depressant.

[0016] Optionally, the cellulose nanocrystals are modified by the following steps:

[0017] The cellulose nanocrystals are added to an ethanol solution, then an acid is added to adjust the pH to 4-5, and then a silane coupling agent is added for reaction to obtain modified cellulose nanocrystals. The hydrophobic modification of the cellulose nanocrystals can further improve the compatibility of the cellulose nanocrystals and further improve the stability and pour point depressing effect of the pour point depressant.

[0018] Optionally, the silane coupling agent is one or more of gamma-glycidoxypropyltrimethoxysilane (KH-560), gamma-methacryloxypropyltrimethoxysilane (KH-570), and 3-isocyanate propyl trimethoxysilane (A-1310).

[0019] Optionally, the inorganic dopant is one or more of mesoporous silica, titanium dioxide, calcium carbonate, talc, and montmorillonite. The inorganic dopant can adsorb gum and asphaltene and reduce the aggregation of wax crystals.

[0020] Optionally, the mesoporous silica has a pore size of 3-5 nm.

[0021] Optionally, the montmorillonite has a layered structure and an interlayer spacing of 1.2-1.5 nm, which can block the penetration of water molecules.

[0022] Optionally, the polymer pour point depressant is one or more of ethylene-vinyl acetate copolymer, ethylene-acrylate copolymer, ethylene-vinyl acetate-acrylate copolymer, ethylene-vinyl acetate-methacrylate copolymer, ethylene-vinyl acetate-polyether-based ethylene copolymer, maleic anhydride-acrylate copolymer, and styrene-maleic anhydride-acrylate copolymer. The organic nanomaterial can form a hydrogen bond network with the carboxyl groups of the polymer pour point depressant through the surface hydroxyl groups or phenolic groups, thereby improving the compatibility.

[0023] Optionally, the low-temperature flow improver is poly-alpha-olefin (PAO) or ethylene-propylene copolymer (EPC). Optionally, the molecular weight of the poly-alpha-olefin is 400-1000 g / mol, and further, the molecular weight of the poly-alpha-olefin is 500-800 g / mol. The PAO hydrophobic segment is compatible with the hydrophobic surface of the modified lignin nanospheres or modified cellulose nanospheres, can form a "hydrophobic barrier" to inhibit the adsorption of water molecules on the wax crystal at low temperature, and the PAO and the inorganic dopant can synergistically reduce the diffusion resistance of the wax molecules. The low-viscosity characteristics of the PAO promote the movement of the polymer chain at low temperature, inhibit the formation of a wax crystal network, and the resulting new crude oil pour point depressant has good low-temperature characteristics and can be used at low temperature.

[0024] Optionally, the molecular weight of the ethylene-propylene copolymer is 5000-10000 g / mol. The flexible chain of the EPC is inserted into the hydroxyl network of the modified lignin nanospheres or modified cellulose nanospheres to improve the low-temperature brittleness resistance. The EPC copolymer enhances the low-temperature toughness of the polymer pour point depressant through molecular chain entanglement, and the resulting new crude oil pour point depressant has good low-temperature characteristics and can be used at low temperature.

[0025] Optionally, the crosslinking agent is one or more of glutaraldehyde, polyetheramine, zirconium oxygen cluster, zinc borate, and epoxidized soybean oil. The crosslinking agent, the polymer pour point depressant, the inorganic dopant, and the organic nanomaterial can form a three-dimensional interpenetrating network to further improve the hydrothermal stability and compatibility.

[0026] Optionally, the ionic stabilizer is one or more of 1-vinyl-3-ethylimidazole bistrifluoromethylsulfonylimide salt, 1-butyl-3-methylimidazole bistrifluoromethylsulfonylimide salt, choline benzotriazole salt, and methyl fluorosulfonyl difluoroacetate. The anion in the ionic stabilizer of the application can be adsorbed on the surface of the wax crystal through electrostatic interaction to inhibit its growth, and the long alkyl chain of the cation can be inserted between the wax layers to destroy the ordered arrangement of the crystal, prevent the aggregation of the wax crystal, and promote the emulsification and flow of the crude oil. In addition, the sulfonic acid anion can repel Cl - by strong electrostatic repulsion, reducing the inactivation of the pour point depressant by salt ions, and the imidazole cation can form stable complexes with Ca 2+ and Mg 2+ , thereby improving the salt tolerance of the pour point depressant.

[0027] Optionally, the inorganic dopant is first subjected to an amination treatment, including the following steps: adding the inorganic dopant to a 3-aminopropyl triethoxysilane solution to obtain an aminated inorganic dopant. The inorganic dopant is first subjected to an amination modification treatment to form an interaction with the lignin nanospheres or cellulose nanocrystals, which can improve the compatibility with other raw materials and avoid the agglomeration of the inorganic dopant.

[0028] The second aspect of the present application provides a preparation method of a new crude oil pour point depressant, the preparation method comprising the following steps:

[0029] S1: melting the polymer pour point depressant at a first temperature;

[0030] S2: then adding organic nanomaterials and inorganic dopants to the step S1 melted polymer at a second temperature to obtain a melt blend;

[0031] S3: adding a crosslinking agent and a low-temperature flow improver to the melt blend at a third temperature to continue the mixing;

[0032] S4: adding an ionic stabilizer to the step S3 mixture at a fourth temperature to react, and then extruding and granulating to obtain the new crude oil pour point depressant.

[0033] Optionally, the first temperature is 150-180℃. Optionally, the first temperature is 160-170℃. The polymer matrix is preheated at the first temperature to avoid degradation of the polymer pour point depressant when the temperature exceeds 200℃.

[0034] Optionally, the second temperature is 170-190℃. The polymer is preheated, and then the organic nanomaterials and inorganic dopants are added at this temperature for dispersion, which can prevent agglomeration.

[0035] Optionally, the third temperature is 80-110℃. At this temperature, the crosslinking agent can be dynamically crosslinked with other substances to avoid premature addition of the crosslinking agent leading to gelation.

[0036] Optionally, the fourth temperature is 50-70℃. The ionic stabilizer is added at this temperature at the end to avoid thermal decomposition of the ionic stabilizer.

[0037] Compared with the prior art, the present application at least achieves one of the following beneficial effects:

[0038] (1) The new crude oil pour point depressant of the present application uses a polymer pour point depressant as a base material, adds organic nanomaterials to enhance mechanical properties and pour point depression effect, adds inorganic dopants to improve hydrothermal stability and salt tolerance, adds a crosslinking agent to improve the compatibility between raw materials, adds an ionic stabilizer to shield salt to improve salt tolerance, and adds a low-temperature flow improver to improve low-temperature fluidity. Through the synergistic cooperation of organic nanomaterials, inorganic dopants, polymer pour point depressants, crosslinking agents, low-temperature flow improvers, and ionic stabilizers, the new crude oil pour point depressant has high hydrothermal stability, good salt tolerance, high mechanical strength, and good pour point depression effect.

[0039] (2) The new crude oil pour point depressant of the present application also has good low-temperature characteristics and can be used at low temperatures.

[0040] (3) The novel crude oil pour point depressant of the present application first modifies the lignin nanospheres to improve the compatibility of the lignin nanospheres, thereby ensuring the stability and pour point depressing effect of the pour point depressant.

[0041] (4) The novel crude oil pour point depressant of the present application first modifies the cellulose nanocrystals to improve the compatibility of the cellulose nanocrystals, thereby further improving the stability and pour point depressing effect of the pour point depressant. BRIEF DESCRIPTION OF DRAWINGS

[0042] The drawings described herein are used to provide further understanding of the present application, and form a part of the present application. The illustrative embodiments of the present application and their description serve to explain the present application. In the drawings:

[0043] Figure 1 An exemplary embodiment of the infrared spectrum of the crude oil pour point depressant of the present application is shown. DETAILED DESCRIPTION

[0044] In order to more clearly illustrate the overall concept of the present application, the following detailed description is given in an exemplary manner.

[0045] In the following description, many specific details are set forth in order to provide a thorough understanding of the present application. However, the present application can be practiced in other manners different from those described herein, and therefore the scope of the present application is not limited by the specific embodiments disclosed below.

[0046] In the following examples and comparative examples, the various reagents used are commercially available chemical pure reagents unless otherwise specified. The polymer pour point depressant is a conventional polymer in the prior art.

[0047] Example 1

[0048] In an exemplary embodiment of the present application, the novel crude oil pour point depressant includes lignin nanospheres 5wt%, particle size 10nm, mesoporous silica 5wt%, particle size 100nm, pore size 3nm, ethylene-vinyl acetate copolymer 83wt%, poly-alpha-olefin 2wt%, poly-alpha-olefin molecular weight 400g / mol, crosslinking agent glutaraldehyde 2wt%, and 1-vinyl-3-ethylimidazole bistrifluoromethanesulfonylimidate salt 3wt%.

[0049] The preparation method of the novel crude oil pour point depressant includes the following steps:

[0050] S1: The ethylene-vinyl acetate copolymer is added to a twin-screw extruder and melted at 150°C.

[0051] S2: Then the lignin nanospheres and mesoporous silica are added at a temperature of 170°C to obtain a melt blend.

[0052] S3: Add poly-alpha-olefin and crosslinking agent glutaraldehyde to the melt blend at a temperature of 80 °C and continue mixing.

[0053] S4: Add 1 -vinyl-3-ethylimidazolium bistrifluoromethanesulfonimide salt at a temperature of 50 °C and react, then extrude at an extruder die temperature of 160 °C and pelletize at 2 mm to obtain the novel crude oil pour point depressant.

[0054] Example 2

[0055] In one exemplary embodiment of the present application, the novel crude oil pour point depressant includes lignin nanospheres 8 wt%, particle size 5 nm, montmorillonite 7 wt%, ethylene-acrylate copolymer 75 wt%, ethylene-propylene copolymer 5 wt% with a molecular weight of 5000 g / mol, crosslinking agent polyetheramine 2 wt%, and 1 -butyl-3-methylimidazolium bistrifluoromethanesulfonimide salt 3 wt%.

[0056] The method of preparing the novel crude oil pour point depressant includes the following steps:

[0057] S1 : Add ethylene-acrylate copolymer to a twin-screw extruder and melt at 180 °C.

[0058] S2: Then add lignin nanospheres and montmorillonite at a temperature of 190 °C to obtain a melt blend.

[0059] S3: Add ethylene-propylene copolymer and crosslinking agent polyetheramine to the melt blend at a temperature of 100 °C and continue mixing.

[0060] S4: Add 1 -butyl-3-methylimidazolium bistrifluoromethanesulfonimide salt at a temperature of 70 °C and react, then extrude at an extruder die temperature of 170 °C and pelletize at 3 mm to obtain the novel crude oil pour point depressant.

[0061] Example 3

[0062] In one exemplary embodiment of the present application, the novel crude oil pour point depressant includes lignin nanospheres 6 wt%, particle size 2 nm, titanium dioxide 5 wt%, styrene-maleic anhydride-acrylate copolymer 77 wt%, poly-alpha-olefin 3 wt% with a molecular weight of 500 g / mol, crosslinking agent zinc borate 3 wt%, and choline benzotriazole salt 6 wt%.

[0063] The method of preparing the novel crude oil pour point depressant includes the following steps:

[0064] S1 : Add styrene-maleic anhydride-acrylate copolymer to a twin-screw extruder and melt at 170 °C.

[0065] S2: Then add cellulose nanocrystal and titanium dioxide at temperature 180°C to get the melt blend.

[0066] S3: Add poly alpha-olefin and crosslinking agent zinc borate to the melt blend at temperature 100°C to continue the mixing.

[0067] S4: Add choline benzotriazole salt at temperature 60°C to react, then extrude, extruder die temperature 160°C, cut 2mm to get the new crude oil pour point depressant.

[0068] Example 4

[0069] In one exemplary embodiment of the present application, the new crude oil pour point depressant includes cellulose nanocrystal 6wt%, particle size 2nm, titanium dioxide 5wt%, styrene-maleic anhydride-acrylate copolymer 77wt%, poly alpha-olefin 3wt% with molecular weight 600g / mol, crosslinking agent zinc borate 3wt% and choline benzotriazole salt 6wt%.

[0070] The method of preparing the new crude oil pour point depressant includes the following steps:

[0071] S1: Add styrene-maleic anhydride-acrylate copolymer into the twin-screw extruder to melt at 170°C.

[0072] S2: Then add cellulose nanocrystal and titanium dioxide at temperature 180°C to get the melt blend.

[0073] S3: Add poly alpha-olefin and crosslinking agent zinc borate to the melt blend at temperature 100°C to continue the mixing.

[0074] S4: Add choline benzotriazole salt at temperature 60°C to react, then extrude, extruder die temperature 160°C, cut 2mm to get the new crude oil pour point depressant.

[0075] Example 5

[0076] In one exemplary embodiment of the present application, the new crude oil pour point depressant includes lignin nanospheres 6wt%, particle size 2nm, titanium dioxide 5wt%, particle size 2nm, styrene-maleic anhydride-acrylate copolymer 77wt%, poly alpha-olefin 3wt% with molecular weight 500g / mol, crosslinking agent zinc borate 3wt% and 1-vinyl-3-ethylimidazolium bistrifluoromethylsulfonimide salt 6wt%.

[0077] The method of preparing the new crude oil pour point depressant includes the following steps:

[0078] S0: The lignin nanospheres are first modified, including the following steps: the lignin nanospheres are added into a sodium hydroxide solution with a pH value of 11, 5wt% silane coupling agent KH-570 is added, and the reaction is carried out at 60°C for 4h to obtain silanized lignin nanospheres, the silanized lignin nanospheres are centrifuged and washed, and then the silanized lignin nanospheres are added into a PEG2000 aqueous solution, and stirred at 60°C for 2h, PEG2000 accounts for 20wt% of the lignin nanospheres, to obtain modified lignin nanospheres.

[0079] The titanium dioxide is first subjected to amination treatment: the TiO2nanoparticles are first immersed in a 10% nitric acid solution, stirred at 70°C for 2h, centrifuged and washed to neutral, then dispersed in an ethanol / water mixture, 5wt% 3-aminopropyltriethoxysilane is added, the pH is adjusted to 4, and then washed and dried to obtain aminated titanium dioxide.

[0080] S1: The styrene-maleic anhydride-acrylate copolymer is added into a twin-screw extruder, and the melting is carried out at 170°C.

[0081] S2: Then the modified lignin nanospheres and the aminated titanium dioxide are added at a temperature of 180°C to obtain a melt blend.

[0082] S3: The poly-alpha-olefin and the crosslinking agent zinc borate are added to the melt blend at a temperature of 100°C to continue the mixing.

[0083] S4: 1-Vinyl-3-ethylimidazole bis-trifluoromethanesulfonimide salt is added at a temperature of 60°C to carry out the reaction, and then extruded, the extruder die temperature is 160°C, and the pelletizing is 2mm to obtain the novel crude oil pour point depressant.

[0084] Example 6

[0085] In an exemplary embodiment of the present application, the novel crude oil pour point depressant includes lignin nanospheres 6wt%, a particle size of 2nm, titanium dioxide 5wt%, a particle size of 2nm, styrene-maleic anhydride-acrylate copolymer 77wt%, poly-alpha-olefin 3wt%, the molecular weight of the poly-alpha-olefin is 500g / mol, crosslinking agent epoxidized soybean oil 3wt%, and 1-vinyl-3-ethylimidazole bis-trifluoromethanesulfonimide salt 6wt%.

[0086] The preparation method of the novel crude oil pour point depressant includes the following steps:

[0087] S0: The lignin nanospheres are first modified, including the following steps: the lignin nanospheres are added to a sodium hydroxide solution with a pH value of 11, 10wt% silane coupling agent KH-590 is added, and reaction is carried out at 60°C for 4h to obtain silanized lignin nanospheres, which are centrifuged and washed, and then added to a PEG2000 aqueous solution, and stirred at 60°C for 2h, PEG2000 accounting for 30wt% of the lignin nanospheres, to obtain modified lignin nanospheres.

[0088] The titanium dioxide is first subjected to amination treatment: the TiO2nanoparticles are first immersed in a 10% nitric acid solution, stirred at 70°C for 2h, washed by centrifugation until neutral, and then dispersed in an ethanol / water mixture, 5wt% 3-aminopropyltriethoxysilane is added, the pH is adjusted to 4, and washing and drying are carried out to obtain aminated titanium dioxide.

[0089] S1: The styrene-maleic anhydride-acrylate copolymer is added to a twin-screw extruder, and melting is carried out at 170°C.

[0090] S2: Then the modified lignin nanospheres and the aminated titanium dioxide are added at a temperature of 180°C to obtain a melt blend.

[0091] S3: The poly-alpha-olefin and the crosslinking agent epoxidized soybean oil are added to the melt blend at a temperature of 100°C to continue the mixing.

[0092] S4: 1-Vinyl-3-ethylimidazole bistrifluoromethanesulfonylimide salt is added at a temperature of 60°C to carry out reaction, and then extrusion is carried out, the extruder die temperature is 160°C, and the pelletizing is 2mm to obtain a new crude oil pour point depressant.

[0093] Example 7

[0094] In an exemplary embodiment of the present application, the new crude oil pour point depressant comprises cellulose nanocrystals 6wt%, mesoporous silica with a particle size of 2nm 5wt%, styrene-maleic anhydride-acrylate copolymer 77wt%, poly-alpha-olefin with a molecular weight of 500g / mol 3wt%, crosslinking agent epoxidized soybean oil 3wt%, and 1-vinyl-3-ethylimidazole bistrifluoromethanesulfonylimide salt 6wt%.

[0095] The preparation method of the new crude oil pour point depressant comprises the following steps:

[0096] S0: The cellulose nanocrystals are first modified, including the following steps: the cellulose nanocrystals are added to an ethanol / water mixture, acetic acid is added to adjust the pH to 4, and then silane coupling agent KH-570 is added, stirring is carried out at 70°C for 6h, centrifugal washing and drying are carried out to obtain modified cellulose nanocrystals.

[0097] The mesoporous silica is first subjected to amination treatment: the mesoporous silica is subjected to vacuum drying treatment at 110°C for 2h, then immersed in a 2% hydrochloric acid solution and subjected to ultrasonic treatment for 30min, centrifuged and washed to neutral. Then dispersed in anhydrous toluene, 3wt% 3-aminopropyl triethoxysilane is added, and refluxed at 80°C for 6h under argon protection, and then subjected to centrifugation, washing and drying in sequence to obtain aminated silica.

[0098] S1: The styrene-maleic anhydride-acrylate copolymer is added to a twin-screw extruder and subjected to melt at 170°C.

[0099] S2: Then the modified cellulose nanocrystals and the aminated silica are added at a temperature of 180°C to obtain a melt blend.

[0100] S3: The poly-alpha-olefin and the crosslinking agent epoxidized soybean oil are added to the melt blend at a temperature of 100°C for continued mixing.

[0101] S4: The 1-vinyl-3-ethylimidazole bistrifluoromethanesulfonylimide salt is added at a temperature of 60°C for reaction, and then subjected to extrusion, with an extruder die temperature of 160°C and pelletizing at 2mm to obtain a novel crude oil pour point depressant.

[0102] Example 8

[0103] Based on Example 7, the main difference is that the polymer pour point depressant is a maleic anhydride-acrylate copolymer, and the others are the same as in Example 7.

[0104] Example 9

[0105] Based on Example 7, the main difference is that the crosslinking agent is a zirconium oxygen cluster, and the others are the same as in Example 7.

[0106] Example 10

[0107] Based on Example 1, the main difference is that the particle size of the organic nanomaterial is 200nm.

[0108] Comparative Example 1

[0109] Based on Example 1, the main difference is that no organic nanomaterial is added.

[0110] Comparative Example 2

[0111] Based on Example 1, the main difference is that the organic nanomaterial is 20%.

[0112] Comparative Example 3

[0113] Based on Example 1, the main difference is that the ionic stabilizer is 15%.

[0114] Test Example:

[0115] Point test: The crude oil pour point depressant prepared in the above examples and comparative examples is applied to crude oil with a salinity of 15% and a wax content of 32% for testing in a simulated test environment. Before testing, the sample is preheated to 60°C, then cooled and the pour point is determined, and compared with a blank crude oil sample with a wax content of 10%, to calculate the pour point depression amplitude.

[0116] Salt tolerance test: NaCl, CaCl2, and MgCl2 mixed salt solution is continuously added to the crude oil to simulate different salinity environments, wherein the mass ratio of NaCl, CaCl2, and MgCl2 is 5:1:1, and by adjusting the amount of deionized water, a mixed salt solution with different salinity is prepared. The mixed salt solution with different salinity is added to crude oil with a wax content of 32%, then stirred and preheated to 60°C. The minimum salinity value corresponding to a pour point depression amplitude reduction of more than 50% is tested by comparing with a blank crude oil sample (without adding mixed salt solution).

[0117] Hydrothermal stability test: The crude oil pour point depressant prepared in the above examples and comparative examples is mixed with crude oil with a salinity of 15% and a wax content of 32%, and then placed in a high temperature oven at a temperature of 150°C for 120h. After cooling, the pour point and viscosity are re-determined to evaluate the pour point decay rate.

[0118] Table 1

[0119]

[0120] Referring to Table 1, the novel crude oil pour point depressant prepared in the present application has a pour point depression amplitude of not less than 10°C, a salt tolerance of not less than 10%, and good salt tolerance and pour point depression effect in the process of treating high-salt and high-wax content crude oil. In the hydrothermal stability test, the novel crude oil pour point depressant has a pour point decay rate of not more than 30% after temperature treatment of 120°C or higher, and has good hydrothermal stability.

[0121] In addition, the novel crude oil pour point depressant prepared in the present application has good low temperature properties. When the crude oil pour point depressant prepared in the above examples is applied to crude oil with a salinity of 15% and a wax content of 32%, the pour point is not higher than -12°C, preferably not higher than -25°C (for example, examples 5-9), which can be used in winter low temperature environment (for example, below -10°C), and can improve the flowability of crude oil at low temperature.

[0122] Figure 1 An exemplary embodiment of the infrared spectrum of the novel crude oil pour point depressant of example 5 of the present application is shown. Briefly, 3400-3250cm -1O-H / N-H stretching vibration, 3200-3100 cm -1 C-H stretching vibration, 1700-1650 cm -1 C=O stretching vibration, 1700-1600 cm -1 C=C stretching vibration, 1500-1600 cm -1 C=C aromatic ring skeleton, 1300-1100 cm -1 S=O / S-N stretching vibration, 1100-1000 cm -1 Si-O-Si stretching, 1000-900 cm -1 Ti-O-Ti stretching.

[0123] The above description is merely that of the embodiment of the application, but not intended to limit the application. Since those skilled in the art can make various modifications and changes to the application without departing from the spirit and principle of the application, any modification, equivalent replacement, improvement, etc. made within the spirit and principle of the application shall fall within the scope of the claims of the application.

Claims

1. A novel crude oil pour point depressant, characterized in that, By mass fraction, the novel crude oil pour point depressant comprises 3%-10% organic nanomaterials, 2%-8% inorganic dopants, 70%-85% polymer pour point depressants, 2-5% low-temperature flow improvers, 1%-5% crosslinking agents, and 0.5%-8% ionic stabilizers. Among them, organic nanomaterials are lignin nanospheres or cellulose nanocrystals.

2. The novel crude oil pour point depressant according to claim 1, characterized in that, Organic nanomaterials have a particle size of less than 50 nm.

3. The novel crude oil pour point depressant according to claim 1, characterized in that, The lignin nanospheres are first modified, including the following steps: Lignin nanospheres were added to an alkaline solution, and a silane coupling agent was added to react and obtain silanized lignin nanospheres. The silanized lignin nanospheres were then added to a polyethylene glycol solution to react and obtain modified lignin nanospheres.

4. The novel crude oil pour point depressant according to claim 3, characterized in that, The mass of the silane coupling agent is 5%-12% of the mass of the lignin nanospheres; The mass of polyethylene glycol is 20%-35% of the mass of lignin nanospheres.

5. The novel crude oil pour point depressant according to claim 1, characterized in that, The cellulose nanocrystals are first modified, including the following steps: Cellulose nanocrystals were added to an ethanol solution, then acid was added to adjust the pH to 4-5, and then a silane coupling agent was added to carry out the reaction, thus obtaining modified cellulose nanocrystals.

6. The novel crude oil pour point depressant according to claim 1, characterized in that, The inorganic dopant is one or more of the following: mesoporous silica, titanium dioxide, calcium carbonate, talc, and montmorillonite; And / or the polymer pour point depressant is one or more of the following: ethylene-vinyl acetate copolymers, ethylene-acrylate copolymers, ethylene-vinyl acetate-acrylate copolymers, ethylene-vinyl acetate-methacrylate copolymers, ethylene-vinyl acetate-polyether vinyl copolymers, maleic anhydride-acrylate copolymers, and styrene-maleic anhydride-acrylate copolymers; And / or the crosslinking agent is one or more of glutaraldehyde, polyetheramine, zirconium oxide, zinc borate, and epoxidized soybean oil; And / or the ionic stabilizer is one or more of the following: 1-vinyl-3-ethylimidazolium bis(trifluoromethanesulfonyl)imide salt, 1-butyl-3-methylimidazolium bis(trifluoromethanesulfonyl)imide salt, choline benzotriazole salt, and methyl fluorosulfonyl difluoroacetate. And / or the low-temperature flow improver is one of poly-α-olefin or ethylene-propylene copolymer.

7. The novel crude oil pour point depressant according to claim 1, characterized in that, The inorganic dopant is first subjected to amination treatment, including the following steps: the inorganic dopant is added to a 3-aminopropyltriethoxysilane solution to react and obtain the amination inorganic dopant.

8. A method for preparing a novel crude oil pour point depressant as claimed in any one of claims 1-7, characterized in that, The preparation method includes the following steps: S1: Melt the polymer pour point depressant at the first temperature; S2: Then, at the second temperature, organic nanomaterials and inorganic dopants are added to the molten polymer from step S1 to obtain a molten blend; S3: At the third temperature, add a crosslinking agent and a low-temperature flow improver to the melt blend and continue blending; S4: At the fourth temperature, an ionic stabilizer is added to the mixture from step S3 to react, and then extrusion and granulation are carried out to obtain a new type of crude oil pour point depressant.

9. The preparation method according to claim 8, characterized in that, The first temperature is 150-180℃; And / or the second temperature is 170-190℃; And / or the third temperature is 80-110℃; And / or the fourth temperature is 50-70℃.

10. The preparation method according to claim 9, characterized in that, The extrusion temperature is 150-170℃.

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