Preparation method of a demulsifier for crude oil pretreatment

Abstract

The present invention provides a demulsifier for crude oil pretreatment, belonging to the technical field of oilfield chemical engineering, which includes the following steps: Step S1: Cut the feather fibers into small segments, perform ball milling treatment to obtain nano feather fibers, then perform surface treatment with hydrofluoric acid, and immerse the surface-treated nano feather fibers in a hydrogen peroxide solution, heat and stir to obtain hydrophilic modified nano feather fibers; Step S2: Mix tetraethoxysilane with ethanol, adjust the pH to 7-9, stir at room temperature to generate silica sol, immerse the hydrophilic modified nano feather fibers in the silica sol, continuously stir, dry and cure to obtain a demulsifier for crude oil pretreatment. The demulsifier for crude oil pretreatment of the present invention achieves the purpose of efficient demulsification.

Description

Technical Field

[0001] The present invention relates to the technical field of oilfield chemicals, and specifically relates to a preparation method of a demulsifier for crude oil pretreatment. Background Art

[0002] During the exploitation, transportation, and processing of crude oil, it is easily mixed with formation water or injected water and affected by external mechanical forces (such as pumping, stirring, etc.), and is prone to form stable water-in-oil (W / O) or oil-in-water (O / W) emulsions. Such emulsions are usually composed of crude oil, water, emulsifiers (such as natural surfactants, clay particles, etc.), and mechanical impurities. The stability of the emulsion mainly comes from the existence of the interfacial film, which is formed by natural emulsifiers (such as asphaltenes and resins) adsorbed on the oil-water interface and has high mechanical strength and elasticity. The water, inorganic salts, and mechanical impurities in the emulsion increase the water content of the crude oil, reduce the purity of the crude oil, affect the efficiency of subsequent refining processes, and also accelerate the corrosion of pipelines and equipment, resulting in an increase in the operating costs of oilfields and refineries.

[0003] Crude oil demulsifiers are a class of chemical agents that act on crude oil emulsions through physical and chemical means to rupture the interfacial film of the emulsion and rapidly separate oil and water. Common crude oil demulsifiers are divided into non-ionic demulsifiers, cationic demulsifiers, anionic demulsifiers, and zwitterionic demulsifiers, etc., but they generally have problems such as poor stability, heavy environmental burden, and difficult cost control.

[0004] A patent document with the publication number CN114736337B discloses a demulsifier, which is a copolymer containing aromatic hydrocarbons with vinyl groups, long-chain α-olefins, and allyl alcohol polyethers. The molar ratio of the aromatic hydrocarbon monomer with vinyl groups, α-olefin monomer, and allyl alcohol polyether monomer in the copolymer is 1:1:(0.8 - 1.2), and the number-average molecular weight of the polymer is 4000 - 7000, and it is prepared by the method of free radical polymerization of monomers. The demulsifier prepared in this patent document has strong selectivity and has a high demulsification efficiency when applied to the treatment of heavy oil. However, the demulsification effect decreases when treating other crude oils, and the copolymer is difficult to degrade in the natural environment and is prone to potential environmental problems. In addition, the preparation cost of this demulsifier is also relatively high.

[0005] Therefore, it is necessary to provide a preparation method of a demulsifier for crude oil pretreatment to solve the problems existing in the above-mentioned prior art. Summary of the Invention

[0006] In view of this, the present invention provides a preparation method of a demulsifier for crude oil pretreatment, which can achieve the purpose of high-efficiency demulsification, good stability, economy, and environmental protection of the demulsifier.

[0007] The specific solution of the present invention is as follows. A preparation method of a demulsifier for crude oil pretreatment includes the following steps:

[0008] Step S1: Cut the feather fibers into small segments, perform ball milling treatment to obtain nano-feather fibers, then conduct surface treatment with hydrofluoric acid. Immerse the surface-treated nano-feather fibers in hydrogen peroxide solution, heat and stir to obtain hydrophilic modified nano-feather fibers;

[0009] Step S2: Mix tetraethoxysilane with ethanol, adjust the pH to 7 - 9, stir at room temperature to generate silica sol. Immerse the hydrophilic modified nano-feather fibers in the silica sol, continuously stir, dry and cure to obtain a crude oil pretreatment demulsifier.

[0010] Feather fiber is a natural, high molecular material with a porous structure, and its main component is keratin. Keratin contains a large number of polar groups (such as carboxyl, amino, and sulfhydryl groups), which can provide adsorption sites in emulsified crude oil, enabling the feather fibers to form stable adsorption at the oil-water interface, facilitating the interaction between the demulsifier and the oil-water interface, and weakening the strength of the interfacial film, thereby achieving the demulsification effect.

[0011] The nano-treated feather fibers have a large specific surface area, which can increase the interface in contact with the emulsion and improve the demulsification efficiency. The surface of the nano-feather fibers is roughened by hydrofluoric acid treatment, increasing the surface roughness of the nano-feather fibers, thereby enhancing the physicochemical interaction between the nano-feather fibers and the oil-water interface. The surface roughening treatment significantly increases the specific surface area of the nano-feather fibers, providing more adsorption sites, which is beneficial to the distribution of the demulsifier at the oil-water interface. The roughened surface increases the van der Waals force and capillary force on the interface through microstructures (such as pores and protrusions), enhancing the capture ability of the nano-feather fibers for the emulsion interface and achieving efficient demulsification. The rough surface can also physically weaken the integrity of the emulsion interfacial film and accelerate the stratification of the emulsion to achieve the purpose of demulsification. Then, hydrogen peroxide is used to conduct hydrophilic modification on the nano-feather fibers. The strong oxidizing property of hydrogen peroxide can increase the number of carboxyl, hydroxyl, and other polar groups on the surface of the nano-feather fibers. These groups can form hydrogen bonds with water molecules, thereby improving the hydrophilicity of the nano-feather fibers. After the hydrophilicity is enhanced, the nano-feather fibers can adsorb water-phase molecules faster, increase the mutual collision between the dispersed-phase droplets, promote the aggregation and fusion of the water droplets in the emulsion, form larger droplets, and accelerate the oil-water separation to achieve demulsification.

[0012] Through the sol-gel method, tetraethoxysilane is used to prepare silica sol. The hydrophilic modified nano feather fibers are compounded with the silica sol to form a demulsifier with high surface energy and structural stability, improving the treatment ability for crude oil emulsions. In the silica sol, tetraethoxysilane hydrolyzes to form silanol groups, which further condense to form silicon-oxygen bonds, forming a silica network. Then, it forms a composite material with the nano feather fibers to obtain a demulsifier for crude oil pretreatment, which helps the demulsifier maintain structural stability in complex environments (such as high temperature and high pressure), avoiding the failure of the demulsifier during the oil-water separation process. Moreover, the silica network can further increase the surface energy, enabling the demulsifier to spread rapidly at the oil-water interface, promoting the reduction of the interfacial tension, helping to destroy the stability of the oil-water interfacial film, and achieving efficient and rapid demulsification. After combining the silica network on the surface of the nano feather fibers, it combines the advantages of both. The nano feather fibers provide multiple adsorption sites, and the silica network enhances the dispersibility and interfacial activity of the demulsifier, thus significantly improving the demulsification efficiency.

[0013] As a natural waste, feather fibers are low-cost and can be used to prepare demulsifiers after simple treatment, greatly reducing the production cost. Moreover, the demulsifier formed by the composite of natural fibers and silica sol has strong environmental protection and is not prone to secondary pollution, significantly reducing the negative impact on the environment.

[0014] Preferably, in the step S1, the speed of ball milling is 1000 - 1200 r / min, the time is 3 - 4 h; the concentration of the hydrogen peroxide solution is 3 - 5 wt%.

[0015] Preferably, the surface treatment includes the following steps: immersing the nano feather fibers in a hydrofluoric acid solution, reacting at 30 - 40 °C for 30 - 60 min, filtering, washing with deionized water, and drying.

[0016] Preferably, the concentration of the hydrofluoric acid solution is 0.09 - 0.11 wt%.

[0017] Preferably, in the step S1, the speed of heating and stirring is 400 - 500 r / min, the time is 30 - 50 min, and the temperature is 50 - 60 °C.

[0018] Preferably, in the step S2, nano tungsten carbide is added before stirring at room temperature.

[0019] Nano tungsten carbide has high hardness and wear resistance, which can improve the durability of the demulsifier in a high-shear environment and extend its service life. Moreover, nano tungsten carbide also has good chemical inertness and thermal stability, which can improve the applicability of the demulsifier and help maintain the stability of the demulsifier. In addition, nano tungsten carbide can cooperate with the porous structure of the nano feather fibers to further increase the specific surface area of the demulsifier, provide more adsorption sites, enhance the interfacial adsorption ability, and improve the demulsification efficiency.

[0020] Preferably, in the step S2, the speed of stirring at room temperature is 300-500 r / min, and the time is 1-2 h; the speed of continuous stirring is 200-300 r / min, the time is 2-3 h, and the temperature is 30-40 °C.

[0021] Preferably, in the step S2, the drying temperature is 50-60 °C, and the time is 10-12 h; the curing temperature is 120-130 °C, and the time is 2-3 h.

[0022] Preferably, it comprises the following components in parts by weight:

[0023] 2-3 parts of hydrophilic modified nano feather fiber, 10-15 parts of tetraethoxysilane, 30-40 parts of ethanol, 5-10 parts of deionized water and 1-2 parts of ammonia water.

[0024] Preferably, the demulsifier further comprises 0.5-2 parts of nano tungsten carbide;

[0025] The raw materials of the hydrophilic modified nano feather fiber include 4-6 parts of feather fiber, 50-60 parts of hydrofluoric acid solution and 40-50 parts of hydrogen peroxide solution.

[0026] The above technical solutions of the present invention have at least the following beneficial effects:

[0027] (1) Feather fiber is a natural polymer material, mainly composed of keratin, containing polar groups. After nanometerization, the specific surface area increases, which can provide adsorption sites at the oil-water interface, weaken the strength of the interfacial film, and improve the demulsification efficiency.

[0028] (2) By treating with hydrofluoric acid, the surface of the nano feather fiber is roughened, its specific surface area is increased, more adsorption sites are provided, the capture ability of the demulsifier for the emulsification interface is enhanced, the integrity of the interfacial film is weakened, the emulsion stratification is accelerated, and efficient demulsification is achieved.

[0029] (3) Through hydrogen peroxide modification, the carboxyl and hydroxyl groups on the surface of the feather fiber increase, the hydrophilicity is significantly improved, the coalescence of water droplets is promoted, the strength of the interfacial film is reduced, and the oil-water separation is accelerated.

[0030] (4) By compounding the modified nano feather fiber with silica sol, the silica sol hydrolyzes and condenses on the surface of the modified nano feather fiber to form a silica network. The silica network enhances the dispersibility and interfacial activity of the demulsifier, promotes the reduction of the interfacial tension, destroys the stability of the oil-water interfacial film, and thus improves the demulsification efficiency. Specific embodiments

[0031] To make the objectives, technical solutions, and advantages of the embodiments of the present invention clearer, the technical solutions of the embodiments of the present invention will be clearly and completely described below in conjunction with the embodiments of the present invention. Obviously, the described embodiments are part of the embodiments of the present invention, rather than all of them. All other embodiments obtained by those of ordinary skill in the art based on the described embodiments of the present invention fall within the scope of protection of the present invention.

[0032] Example 1

[0033] Take 6 parts of feather fibers, place them in deionized water, add a neutral detergent, wash to remove surface dirt and grease, then rinse several times with deionized water and dry. The dried feathers are cut into small pieces and put into a high-energy ball mill. Set the speed to 1100 r / min and grind for 3.5 h to obtain nano-feather fibers. Put the obtained nano-feather fibers into 55 parts of 0.1 wt% hydrofluoric acid solution, control the temperature at 35 °C, keep the reaction time for 50 min. After the reaction is completed, filter, wash with deionized water until neutral, and dry to obtain surface-treated nano-feather fibers. Add the surface-treated nano-feather fibers to 45 parts of 4.5 wt% hydrogen peroxide solution, stir at a speed of 300 r / min at 50 °C for 50 min. After the reaction is completed, filter, wash, and dry to obtain hydrophilic modified nano-feather fibers.

[0034] Mix 15 parts of tetraethoxysilane evenly with 40 parts of ethanol, slowly add 10 parts of deionized water and 2 parts of ammonia water, adjust the pH of the solution to 7 - 9, then add 1.5 parts of nano-tungsten carbide, and react under stirring at 400 r / min for 1.5 h to obtain a stable silica sol. Immerse 3 parts of hydrophilic modified nano-feather fibers in the silica sol, stir at a speed of 250 r / min at 30 °C for 3 h, take out and dry at 50 °C for 12 h, and further cure the dried sample at 120 °C for 3 h to obtain a crude oil pretreatment demulsifier.

[0035] Example 2

[0036] Take 5 portions of feather fibers, place them in deionized water, add a neutral detergent, wash to remove surface dirt and grease, then rinse several times with deionized water and dry. Cut the dried feathers into small pieces, put them into a high-energy ball mill, set the speed at 1000 r / min, and grind for 4 h to obtain nano-feather fibers. Put the obtained nano-feather fibers into 55 portions of 0.1 wt% hydrofluoric acid solution, control the temperature at 40 °C, maintain the reaction time for 30 min. After the reaction is completed, filter, wash with deionized water until neutral, and dry to obtain surface-treated nano-feather fibers. Add the surface-treated nano-feather fibers to 40 portions of 3.5 wt% hydrogen peroxide solution, stir at a speed of 350 r / min at 55 °C for 40 min. After the reaction is completed, filter, wash, and dry to obtain hydrophilically modified nano-feather fibers.

[0037] Mix 12 portions of tetraethoxysilane and 35 portions of ethanol evenly, slowly add 5 portions of deionized water and 1.5 portions of ammonia water, adjust the pH of the solution to 7 - 9, and react for 1 h under stirring conditions at 500 r / min to obtain a stable silica sol. Immerse 2 portions of hydrophilically modified nano-feather fibers in the silica sol, stir at a speed of 200 r / min at 30 °C for 2 h, take them out and dry at 60 °C for 10 h, and further cure the dried sample at 130 °C for 2 h to obtain a crude oil pretreatment demulsifier.

[0038] Example 3

[0039] Take 6 portions of feather fibers, place them in deionized water, add a neutral detergent, wash to remove surface dirt and grease, then rinse several times with deionized water and dry. Cut the dried feathers into small pieces, put them into a high-energy ball mill, set the speed at 1200 r / min, and grind for 3 h to obtain nano-feather fibers. Put the obtained nano-feather fibers into 60 portions of 0.09 wt% hydrofluoric acid solution, control the temperature at 30 °C, maintain the reaction time for 60 min. After the reaction is completed, filter, wash with deionized water until neutral, and dry to obtain surface-treated nano-feather fibers. Add the surface-treated nano-feather fibers to 42 portions of 5 wt% hydrogen peroxide solution, stir at a speed of 400 r / min at 60 °C for 35 min. After the reaction is completed, filter, wash, and dry to obtain hydrophilically modified nano-feather fibers.

[0040] Mix 15 parts of tetraethoxysilane and 40 parts of ethanol evenly, slowly add 8 parts of deionized water and 2 parts of ammonia water, adjust the pH of the solution to 7 - 9, then add 0.5 part of nano tungsten carbide, and react for 1.5 h under the stirring condition of 300 r / min to obtain a stable silica sol. Immerse 3 parts of hydrophilically modified nano feather fibers into the silica sol, stir at a speed of 250 r / min for 2.5 h at 40 °C, take them out and dry at 55 °C for 11 h, and further cure the dried sample at 125 °C for 2.5 h to obtain a demulsifier for crude oil pretreatment.

[0041] Example 4

[0042] Take 4 parts of feather fibers, place them in deionized water, add a neutral detergent, wash to remove surface dirt and grease, then rinse several times with deionized water and dry. Cut the dried feathers into small pieces, put them into a high-energy ball mill, set the speed at 1050 r / min, and grind for 3.5 h to obtain nano feather fibers. Put the obtained nano feather fibers into 50 parts of 0.09 wt% hydrofluoric acid solution, control the temperature at 35 °C, keep the reaction time for 45 min, after the reaction, filter, wash with deionized water until neutral, and dry to obtain surface-treated nano feather fibers. Add the surface-treated nano feather fibers to 50 parts of 3.5 wt% hydrogen peroxide solution, stir at a speed of 350 r / min for 30 min at 60 °C, after the reaction is completed, filter, wash, and dry to obtain hydrophilically modified nano feather fibers.

[0043] Mix 10 parts of tetraethoxysilane and 30 parts of ethanol evenly, slowly add 7 parts of deionized water and 1 part of ammonia water, adjust the pH of the solution to 7 - 9, react for 1.5 h under the stirring condition of 350 r / min to obtain a stable silica sol. Immerse 2.5 parts of hydrophilically modified nano feather fibers into the silica sol, stir at a speed of 300 r / min for 2 h at 35 °C, take them out and dry at 60 °C for 11 h, and further cure the dried sample at 130 °C for 2 h to obtain a demulsifier for crude oil pretreatment.

[0044] Example 5

[0045] Take 5 portions of feather fibers, place them in deionized water, add a neutral detergent, wash to remove surface dirt and grease, then rinse multiple times with deionized water and dry. The dried feathers are cut into small pieces, put into a high-energy ball mill, set the speed at 1150 r / min, and grind for 3 h to obtain nano-feather fibers. Put the obtained nano-feather fibers into 50 portions of 0.1 wt% hydrofluoric acid solution, control the temperature at 40 °C, maintain the reaction time for 55 min. After the reaction is completed, filter, wash with deionized water until neutral, and dry to obtain surface-treated nano-feather fibers. Add the surface-treated nano-feather fibers to 48 portions of 3 wt% hydrogen peroxide solution, stir at a speed of 400 r / min at 50 °C for 40 min. After the reaction is completed, filter, wash, and dry to obtain hydrophilically modified nano-feather fibers.

[0046] Mix 15 portions of tetraethoxysilane and 35 portions of ethanol evenly, slowly add 6 portions of deionized water and 1.5 portions of ammonia water, adjust the pH of the solution to 7 - 9, then add 2 portions of nano-tungsten carbide, and react under stirring at 300 r / min for 2 h to obtain a stable silica sol. Immerse 2 portions of hydrophilically modified nano-feather fibers in the silica sol, stir at a speed of 200 r / min at 40 °C for 3 h, take out and dry at 50 °C for 12 h, and further cure the dried sample at 120 °C for 2.5 h to obtain a crude oil pretreatment demulsifier.

[0047] Example 6

[0048] Take 6 portions of feather fibers, place them in deionized water, add a neutral detergent, wash to remove surface dirt and grease, then rinse multiple times with deionized water and dry. The dried feathers are cut into small pieces, put into a high-energy ball mill, set the speed at 1100 r / min, and grind for 3.5 h to obtain nano-feather fibers. Put the obtained nano-feather fibers into 60 portions of 0.11 wt% hydrofluoric acid solution, control the temperature at 30 °C, maintain the reaction time for 35 min. After the reaction is completed, filter, wash with deionized water until neutral, and dry to obtain surface-treated nano-feather fibers. Add the surface-treated nano-feather fibers to 45 portions of 4.5 wt% hydrogen peroxide solution, stir at a speed of 300 r / min at 55 °C for 50 min. After the reaction is completed, filter, wash, and dry to obtain hydrophilically modified nano-feather fibers.

[0049] Mix 12 parts of tetraethoxysilane with 40 parts of ethanol evenly, slowly add 9 parts of deionized water and 2 parts of ammonia water, adjust the pH of the solution to 7 - 9, react for 1 h under the stirring condition of 450 r / min to obtain a stable silica sol. Immerse 3 parts of hydrophilically modified nano feather fibers into the silica sol, stir at a speed of 300 r / min at 30 °C for 2 h, take out and dry at 60 °C for 10 h, and further cure the dried sample at 130 °C for 2 h to obtain a demulsifier for crude oil pretreatment.

[0050] Example 7

[0051] Take 4 parts of feather fibers, place them in deionized water, add a neutral detergent, wash to remove surface dirt and grease, then rinse with deionized water multiple times and dry. Cut the dried feathers into small pieces, put them into a high-energy ball mill, set the speed at 1200 r / min, and grind for 3 h to obtain nano feather fibers. Put the obtained nano feather fibers into 55 parts of 0.11 wt% hydrofluoric acid solution, control the temperature at 35 °C, keep the reaction time for 50 min, after the reaction is completed, filter, wash with deionized water until neutral, and dry to obtain surface-treated nano feather fibers. Add the surface-treated nano feather fibers to 40 parts of 4 wt% hydrogen peroxide solution, stir at a speed of 350 r / min at 60 °C for 40 min, after the reaction is completed, filter, wash, and dry to obtain hydrophilically modified nano feather fibers.

[0052] Mix 10 parts of tetraethoxysilane with 30 parts of ethanol evenly, slowly add 10 parts of deionized water and 2 parts of ammonia water, adjust the pH of the solution to 7 - 9, then add 1 part of nano tungsten carbide, react for 1.5 h under the stirring condition of 400 r / min to obtain a stable silica sol. Immerse 2.5 parts of hydrophilically modified nano feather fibers into the silica sol, stir at a speed of 250 r / min at 35 °C for 2.5 h, take out and dry at 50 °C for 11 h, and further cure the dried sample at 125 °C for 2 h to obtain a demulsifier for crude oil pretreatment.

[0053] Example 8

[0054] Take 4 portions of feather fibers, place them in deionized water, add a neutral detergent, wash to remove surface dirt and grease, then rinse multiple times with deionized water and dry. The dried feathers are cut into small segments, put into a high-energy ball mill, set the speed at 1200 r / min, and grind for 3 h to obtain nano-feather fibers. Put the obtained nano-feather fibers into 55 portions of 0.11 wt% hydrofluoric acid solution, control the temperature at 35 °C, keep the reaction time for 50 min, after the reaction ends, filter, wash with deionized water until neutral, and dry to obtain surface-treated nano-feather fibers. Add the surface-treated nano-feather fibers to 40 portions of 4 wt% hydrogen peroxide solution, stir at a speed of 350 r / min at 60 °C for 40 min, after the reaction is completed, filter, wash, and dry to obtain hydrophilic modified nano-feather fibers.

[0055] Mix 10 portions of tetraethoxysilane with 30 portions of ethanol evenly, slowly add 10 portions of deionized water and 2 portions of ammonia water, adjust the pH of the solution to 7 - 9, and react under stirring conditions at 400 r / min for 1.5 h to obtain a stable silica sol. Immerse 2.5 portions of hydrophilic modified nano-feather fibers into the silica sol, stir at a speed of 250 r / min at 35 °C for 2.5 h, take it out and dry at 50 °C for 11 h, and further cure the dried sample at 125 °C for 2 h to obtain a crude oil pretreatment demulsifier.

[0056] The present invention also carried out comparative examples and related tests.

[0057] Comparative Example 1

[0058] The difference between Comparative Example 1 and Example 1 is that hydrophilic modified nano-feather fibers were not prepared, and other components and preparation methods are the same as those in Example 1.

[0059] Comparative Example 2

[0060] The difference between Comparative Example 2 and Example 1 is that tetraethoxysilane was not used for the preparation of silica sol, and other components and preparation methods are the same as those in Example 1.

[0061] Comparative Example 3

[0062] The difference between Comparative Example 3 and Example 1 is that the nano-feather fibers were not surface-treated with hydrofluoric acid, and other components and preparation methods are the same as those in Example 1.

[0063] Performance detection test

[0064] The demulsifiers prepared in Examples 1-8 and Comparative Examples were used for demulsification tests. The crude oil emulsion used was a water-in-oil type crude oil emulsion with a water content of 30%, and the mass-volume ratio of the demulsifier to the crude oil emulsion was 600 mg / L. The test method was based on SY / T5281—2000 "Testing Method for the Performance of Crude Oil Demulsifiers (Bottle Test Method)", and the demulsification tests were carried out at room temperature and 65 °C respectively for 60 min. The results are shown in Table 1.

[0065] Table 1

[0066]

[0067] According to the data in Table 1, compared with Example 1, the demulsifier prepared in Comparative Example 1 did not prepare hydrophilic modified nano feather fibers, resulting in an affected demulsification effect, indicating that hydrophilic modification is beneficial for the demulsifier to enter the oil-water interface, destroy the stability of the interfacial film, and improve the demulsification effect of the demulsifier; compared with Example 1, the demulsification effect at room temperature in Comparative Example 2 decreased slightly, but the demulsification effect at 65 °C decreased significantly, indicating that the compounding of silica is beneficial for improving the demulsification effect of the demulsifier and can also help the demulsifier maintain stability in a higher temperature environment; in Comparative Example 3, hydrofluoric acid was not used for surface treatment of the nano feather fibers. Compared with the demulsifier prepared in Example 1, there was a certain gap in the demulsification effect, indicating that hydrofluoric acid surface treatment can roughen the surface of the nano feather fibers, contribute to the destruction of the integrity of the interfacial film by the demulsifier, promote the stratification of the emulsion, and achieve efficient demulsification.

[0068] Compared with Example 7, nano tungsten carbide was not added in the preparation of silica sol in Example 8, resulting in a lower demulsification effect of the prepared demulsifier than that of Example 7, especially in the environment of 65 °C, and the decrease was more obvious, indicating that nano tungsten carbide is beneficial for improving the demulsification efficiency of the demulsifier in a higher temperature environment and can also improve the adsorption effect of the demulsifier on the interfacial film.

[0069] The above are 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 preparing a crude oil pretreatment demulsifier, characterized in that: The following steps are involved: Step S1, cutting feather fibers into small segments, ball-milling to obtain nano-feather fibers, and then surface-treating the nano-feather fibers with hydrofluoric acid, immersing the surface-treated nano-feather fibers in a hydrogen peroxide solution, heating and stirring to obtain hydrophilically modified nano-feather fibers; Step S2, tetraethoxysilane and ethanol are mixed, the pH is adjusted to 7-9, and the mixture is stirred at room temperature to generate silica sol, and the hydrophilic modified nano-feather fibers are immersed in the silica sol, the mixture is continuously stirred, and the mixture is dried and solidified to obtain a crude oil pretreatment demulsifier; The demulsifier also includes 1-2 parts of nano tungsten carbide; The raw materials of the hydrophilic modified nano feather fiber include 4-6 parts of feather fiber, 50-60 parts of hydrofluoric acid solution and 40-50 parts of hydrogen peroxide solution.

2. The method for preparing a crude oil pretreatment demulsifier according to claim 1, characterized in that: In the step S1, the ball milling speed is 1000-1200 r / min, the time is 3-4 h; the concentration of the hydrogen peroxide solution is 3-5 wt %.

3. The method for preparing a crude oil pretreatment demulsifier according to claim 1, characterized in that: The surface treatment comprises the following steps: immersing the nano-feather fiber in a hydrofluoric acid solution, reacting at 30-40° C. for 30-60 minutes, filtering, washing with deionized water, and drying.

4. The method for preparing a crude oil pretreatment demulsifier according to claim 3, characterized in that: The concentration of the hydrofluoric acid solution is 0.09-0.11 wt %.

5. The method for preparing a crude oil pretreatment demulsifier according to claim 1, characterized in that: In the step S1, the heating and stirring speed is 400-500 r / min, the time is 30-50 min, and the temperature is 50-60°C.

6. The method for preparing a crude oil pretreatment demulsifier according to claim 1, characterized in that: In the step S2, nano-tungsten carbide is added before stirring at room temperature.

7. The method for preparing a crude oil pretreatment demulsifier according to claim 1, characterized in that: In step S2, the stirring speed at room temperature is 300-500 r / min for 1-2 h; the continuous stirring speed is 200-300 r / min for 2-3 h at a temperature of 30-40°C.

8. The method for preparing a crude oil pretreatment demulsifier according to claim 1, characterized in that: In the step S2, the drying temperature is 50-60°C for 10-12 hours; the curing temperature is 120-130°C for 2-3 hours.

9. The method for preparing a crude oil pretreatment demulsifier according to claim 1, characterized in that: The composition comprises the following components in parts by weight: 2-3 parts of hydrophilic modified nano feather fiber, 10-15 parts of tetraethoxysilane, 30-40 parts of ethanol, 5-10 parts of deionized water and 1-2 parts of ammonia water.

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