Preparation method of demulsifier for high-sulfur and high-acid crude oil

Abstract

This application relates to the technical field of petrochemical engineering, and specifically discloses a preparation method of a demulsifier for high-sulfur and high-acid crude oil. The preparation method includes the following steps: Mix 40 to 60 parts by mass of modified polyether, 25 to 30 parts by mass of zwitterionic surfactant, and 10 to 12 parts by mass of solvent evenly, heat up to 50 to 70 °C, add 3 to 8 parts by mass of activated alumina, 8 to 16 parts by mass of anti-acid agent, and 2 to 4 parts by mass of corrosion inhibitor, mix evenly, add 0.5 to 1 part by mass of defoamer, mix evenly, cool down, and let it stand for stratification to obtain the demulsifier; the anti-acid agent includes ethanolamine and zinc oxide. The demulsifier prepared in this application not only performs excellently in dehydration and promoting oil-water separation, but also can improve the quality of crude oil to a certain extent, reducing the acid value and sulfur content.

Description

Technical Field

[0001] This application relates to the technical field of petrochemical engineering, and more specifically, to a method for preparing a demulsifier for high-sulfur and high-acid crude oil. Background Art

[0002] High-sulfur and high-acid crude oil refers to crude oil with a sulfur content higher than 2% (mass fraction) and an acid value (calculated as KOH) greater than 1.0 mg / g. In this type of crude oil, sulfur elements mainly exist in the forms of inorganic sulfur (such as hydrogen sulfide) and organic sulfur compounds (mercaptans, sulfides, thiophenes, etc.), while the acidic substances in the crude oil are mainly composed of naphthenic acids.

[0003] In the emulsion system formed by high-sulfur and high-acid crude oil, demulsification faces many severe challenges. Due to the interaction of active components such as naphthenic acids, asphaltenes, and some resins, a tough and stable interfacial film is formed at the oil-water interface, making it difficult for water droplets to coalesce and making demulsification extremely difficult. At the same time, the presence of substances such as hydrogen sulfide not only causes the crude oil to have strong corrosiveness but also reacts with metal ions in the aqueous phase to generate various sulfide precipitates. These sulfide precipitates may adhere to the oil-water interface or the surface of water droplets, further enhancing the stability of the interfacial film or changing the charge characteristics of the water droplet surface, thus exacerbating the difficulty of demulsification. In addition, organic sulfur compounds have certain surface activity, and they can adsorb on the oil-water interface and act together with other emulsifiers in the crude oil (such as naphthenic acids) to form a more stable interfacial film. Moreover, as the extraction, transportation, and storage time of the crude oil extend, further chemical reactions may occur among the components in the crude oil, resulting in a more complex and changeable emulsion system, posing higher requirements for the performance and adaptability of the demulsifier.

[0004] The patent application document with the publication number CN103374386A discloses a composite demulsifier. This composite demulsifier is a solution, and by mass, it includes: 5 - 60 parts of polyoxyethylene polyoxypropylene block polyether; 2 - 10 parts of primary amide; 1 - 20 parts of C2 - C6 carboxylic acid and 20 - 90 parts of water; the primary amide is one or several of C2 - C6 fatty amides and nicotinamide.

[0005] When the composite demulsifier prepared in this patent application document is used for high-acid crude oil, the C2 - C6 carboxylic acid may interact with acidic components such as naphthenic acids in the crude oil, which may further stabilize the acidic film at the oil-water interface, resulting in poor demulsification effect. Moreover, the carbon chain of the carboxylic acid is relatively short (C2 - C6), and its lipophilic property is relatively limited. Its solubility in the oil phase and affinity for the oil phase may not be sufficient to enable it to effectively act at the oil-water interface. Summary of the Invention

[0006] In order to enhance the demulsification effect of the demulsifier in high-sulfur and high-acid crude oil, the present application provides a preparation method for a demulsifier for high-sulfur and high-acid crude oil.

[0007] The present application provides a preparation method for a demulsifier for high-sulfur and high-acid crude oil, adopting the following technical solution:

[0008] A preparation method for a demulsifier for high-sulfur and high-acid crude oil includes the following steps:

[0009] Mix 40 - 60 parts by mass of modified polyether, 25 - 30 parts by mass of zwitterionic surfactant, and 10 - 12 parts by mass of solvent evenly, heat up to 50 - 70 °C, add 3 - 8 parts by mass of activated alumina, 8 - 16 parts by mass of acid-resistant agent, and 2 - 4 parts by mass of corrosion inhibitor, mix evenly, add 0.5 - 1 part by mass of defoamer, mix evenly, cool down, and let it stand for layering to obtain the demulsifier; the acid-resistant agent includes ethanolamine and zinc oxide.

[0010] Preferably, at 30 - 40 °C, mix 40 - 60 parts by mass of modified polyether, 25 - 30 parts by mass of zwitterionic surfactant, and 10 - 12 parts by mass of solvent evenly.

[0011] Preferably, the mass ratio of ethanolamine to zinc oxide is (5 - 10) : (3 - 6).

[0012] Preferably, the particle size distribution of the zinc oxide is 50 - 100 nm.

[0013] Preferably, the corrosion inhibitor is oleic acid imidazoline.

[0014] Preferably, the particle size distribution of the activated alumina is 1 - 10 μm.

[0015] Preferably, the defoamer is silicone rubber defoamer.

[0016] By adopting the above technical solution, first, the modified polyether can quickly migrate to the oil-water interface and gradually arrange into an interfacial film, and the addition of the zwitterionic surfactant can further enhance the stability and strength of this interfacial film, thereby effectively reducing the surface tension of the oil-water interface, and through different action mechanisms, jointly promoting the aggregation and separation of oil droplets and water droplets, thus improving the demulsification efficiency.

[0017] Secondly, when activated alumina and antacids are used in combination, activated alumina can pre-adsorb and remove some acidic substances in crude oil, reducing the content of acidic substances in crude oil, enabling the antacids to more effectively neutralize the remaining acidic substances. The formed neutralization products may be further adsorbed by activated alumina, thus preventing these products from redissolving in crude oil or interfering with the demulsification process. This synergistic effect not only improves the treatment efficiency of acidic substances but also maintains the stability of the demulsification system. At the same time, the combined action of activated alumina and antacids can also maintain the pH balance of the demulsifier system, thereby ensuring that the demulsifier can continuously and effectively play its role.

[0018] Finally, the addition of corrosion inhibitors provides an additional protective layer for metal equipment. Based on the actions of activated alumina and antacids, the protective film of the corrosion inhibitor becomes more durable and effective. Even when the activated alumina is adsorbed saturated or the antacids are exhausted, the corrosion inhibitor can still provide necessary protection to prevent the equipment from further corrosion damage. This multiple protection system greatly enhances the durability and safety of the equipment.

[0019] Preferably, the solvent is toluene.

[0020] Preferably, the preparation method of the modified polyether includes the following steps:

[0021] S11: Under an inert atmosphere, polyalkylene polyamine, catalyst A and solvent are mixed evenly in a reactor, heated to 110 - 130 °C, and then a part of propylene oxide is added to the reactor in 4 - 6 portions. After each addition, the reaction is carried out for 15 - 20 min; then a part of ethylene oxide is added to the reactor and the reaction is carried out for 60 - 90 min. Another part of propylene oxide is added to the reactor in 2 - 4 portions. After each addition, the reaction is carried out for 10 - 15 min. Then another part of ethylene oxide is added to the reactor, heated to 120 - 140 °C, and after reacting for 50 - 70 min, the temperature is lowered, distilled, and washed to obtain a polyether intermediate with a comb-like structure;

[0022] S12: Under an inert atmosphere, the polyether intermediate, catalyst B, solvent and allyl sulfonic acid lactone are mixed evenly in a reactor, heated to 90 - 110 °C, and the reaction is carried out for 2 - 4 h. The temperature is lowered, distilled, and washed to obtain the modified polyether;

[0023] The mass ratio of the polyalkylene polyamine, propylene oxide and ethylene oxide is (15 - 20):(15 - 20):(60 - 70), and the dosage of the allyl sulfonic acid lactone is 5% - 15% of the total mass of the polyalkylene polyamine, propylene oxide and ethylene oxide.

[0024] Preferably, the catalyst A is potassium hydroxide, and the dosage of the potassium hydroxide is 1% - 2% of the total mass of the polyalkylene polyamine, propylene oxide and ethylene oxide.

[0025] Preferably, the catalyst B is triethylamine, and the dosage of the triethylamine is 1% - 3% of the total mass of polyalkylene polyamine, propylene oxide, ethylene oxide, and allyl sulfonic lactone.

[0026] Preferably, the polyalkylene polyamine is at least one of diethylenetriamine and triethylenetetramine.

[0027] Preferably, in step S11, under an inert atmosphere, polyalkylene polyamine, catalyst A, and a solvent are mixed evenly in a reactor, heated to 110 - 130°C, with a pressure of 0.2 - 0.4 MPa, and then a part of propylene oxide is added to the reactor in 4 - 6 portions. After each addition, the reaction is carried out for 15 - 20 min; then a part of ethylene oxide is added to the reactor and the reaction is carried out for 60 - 90 min. Another part of propylene oxide is added to the reactor in 2 - 4 portions. After each addition, the reaction is carried out for 10 - 15 min. Then another part of ethylene oxide is added to the reactor, heated to 120 - 140°C, and at the same time the pressure is controlled at 0.3 - 0.5 MPa. After the reaction for 50 - 70 min, the temperature is lowered, distilled, and washed to obtain a polyether intermediate in a comb-like structure.

[0028] By adopting the above technical solution, a modified polyether is further prepared by compounding a polyether intermediate in a comb-like structure with allyl sulfonic lactone. On the one hand, sulfonic acid groups are introduced into the polyether molecules, which can not only improve the chemical stability of the polyether in high-sulfur and high-acid crude oil, making it more resistant to the erosion of acidic components in the crude oil, but also enhance the activity of the polyether at the oil-water interface, making it more effectively break down the stable emulsion film dominated by acidic components and improving the demulsification effect. On the other hand, zwitterionic surfactants can be filled between the polyether intermediate molecules, further enhancing the stability of the interfacial film. Their synergistic effect can more effectively reduce the oil-water interfacial tension and improve the crude oil demulsification efficiency.

[0029] Preferably, the preparation method of the zwitterionic surfactant includes the following steps:

[0030] Oleic acid, monomer A, a solvent, and an antioxidant are mixed evenly. Under an inert atmosphere, it is heated to 100 - 120°C, and p-toluenesulfonic acid is added, and the reaction is carried out for 2 - 4 h to obtain an intermediate; the temperature is lowered to 70 - 90°C, a mixture of polyethylene glycol glycidyl ether and polypropylene glycol glycidyl ether and triethylamine are added, mixed evenly, and the reaction is carried out for 3 - 5 h. The temperature is lowered to 60 - 80°C, leaf alcohol and azobisisobutyronitrile are added and mixed evenly, and the reaction is carried out for 2 - 3.5 h. Then butyl maleate is added and mixed evenly, and the reaction is carried out for 2.5 - 4 h. The temperature is lowered, washed, dried, and distilled to obtain a zwitterionic surfactant in a comb-like structure;

[0031] The monomer A is at least one of 2,6-diaminopyridine and 1-(3-aminopropyl)imidazole;

[0032] The molar ratio of oleic acid to monomer A is 1:(1~1.2).

[0033] Preferably, the total amount of polyethylene glycol glycidyl ether and polypropylene glycol glycidyl ether is 60%~80% of the mass of oleic acid.

[0034] Preferably, the mass ratio of polyethylene glycol glycidyl ether to polypropylene glycol glycidyl ether is 1.2~1.5:1.

[0035] Preferably, the dosage of leaf alcohol is 12%~18% of the mass of oleic acid, and the molar ratio of monobutyl maleate to leaf alcohol is (0.9~1.1):1.

[0036] The dosage of p-toluenesulfonic acid is 1%~3% of the total mass of oleic acid and monomer A.

[0037] The dosage of triethylamine is 0.5%~1.5% of the total mass of polyethylene glycol glycidyl ether and polypropylene glycol glycidyl ether.

[0038] The dosage of azobisisobutyronitrile is 1%~2% of the total mass of leaf alcohol and monobutyl maleate.

[0039] The antioxidant is butylated hydroxyanisole, and the dosage of butylated hydroxyanisole is 0.5%~1% of the total mass of oleic acid and monomer A.

[0040] By adopting the above technical scheme, the unique comb-shaped structure endows the zwitterionic surfactant molecules with multiple lipophilic and hydrophilic regions, which helps them to better adsorb and spread at the oil-water interface, thereby improving their interfacial activity. The zwitterionic property enables it to flexibly adjust the ionization equilibrium according to different pH environments, and can maintain good solubility and surface activity under acidic, alkaline and neutral conditions, greatly broadening the application scenarios.

[0041] The structure of this zwitterionic surfactant can effectively resist the erosion of acidic substances (such as naphthenic acid) and sulfides (such as hydrogen sulfide, mercaptan, etc.) in high-sulfur and high-acid crude oil, ensuring that the demulsifier can stably and effectively play its role in harsh environments. It works synergistically with other demulsifying components such as modified polyethers, jointly adsorbing on the oil-water interface to strengthen the stability and strength of the interfacial film. At the same time, it can also adjust the charge distribution at the oil-water interface, effectively promoting the aggregation and separation of oil droplets and water droplets, and improving the demulsification efficiency of high-sulfur and high-acid crude oil.

[0042] Preferably, before using the activated alumina, it undergoes the following pretreatment steps:

[0043] Mix tetraethyl orthosilicate, ethanol and water evenly, adjust the pH to 2 - 3, heat up to 35 - 55 °C, react for 3 - 8 h, then cool down to obtain silica sol. Add activated alumina and mix evenly, let stand for 16 - 24 h, separate the solid from the liquid, place at room temperature, age, dry, and calcine to obtain the product.

[0044] Preferably, the volume ratio of tetraethyl orthosilicate, ethanol and water is 1:2 - 4:2 - 4; the mass ratio of activated alumina to silica sol is 1:3 - 5.

[0045] By adopting the above technical solution, on the one hand, the activated alumina pretreated with silica sol has abundant surface active sites, which can not only enhance its adsorption of sulfides and acidic substances, but also produce strong physical and chemical adsorption on emulsifiers (such as asphaltenes and resins) in crude oil emulsion, thus effectively destroying the originally stable emulsifier layer, reducing the repulsive force between oil droplets and water droplets, being conducive to the gradual coalescence of water droplets, and thus enhancing the demulsification effect. On the other hand, more hydrophilic groups (such as silanol groups) are introduced on the surface of the activated alumina pretreated with silica sol. The existence of these hydrophilic groups makes the activated alumina show stronger hydrophilicity in the oil - water emulsion system. When water droplets contact these hydrophilic surfaces, they are more likely to spread out to form a thin water film. As more water droplets spread and fuse on the surface of the pretreated activated alumina, the water film gradually thickens. When the gravity of the water film exceeds other acting forces (such as adhesion force, surface tension, etc.), the water droplets will fall off from the surface of the activated alumina and enter the water phase. This process not only realizes the effective separation of the oil phase and the water phase, but also achieves the purpose of demulsification.

[0046] Preferably, when adding activated alumina, 2 - 5 parts by mass of molecular sieve are also added.

[0047] Preferably, before using the molecular sieve, it undergoes the following pretreatment steps:

[0048] (1) Add the molecular sieve into the copper nitrate solution, mix evenly, heat up to 40 - 60 °C, mix for 18 - 24 h, separate the solid from the liquid, wash, and dry to obtain the preliminarily treated molecular sieve;

[0049] (2) Mix tetraethyl orthosilicate, ethanol and water evenly, adjust the pH to 2 - 3, heat up to 35 - 55 °C, react for 3 - 8 h, then cool down to obtain silica sol. Add the preliminarily treated molecular sieve, mix evenly at room temperature, let stand for 16 - 24 h, separate the solid from the liquid, place at room temperature, dry, and calcine to obtain the preliminarily coated molecular sieve;

[0050] (3) Add the preliminarily coated molecular sieve into the polyethylene glycol solution, mix evenly, heat up to 45 - 65 °C, mix for 6 - 8 h, separate the solid from the liquid, wash, and dry to obtain the product.

[0051] Preferably, the volume ratio of tetraethyl orthosilicate, ethanol and water is 1:2-4:2-4;

[0052] Preferably, the concentration of the copper nitrate solution is 0.2-0.4 mol / L; the concentration of the polyethylene glycol solution is 6%-8%; the mass-volume ratio of the molecular sieve, the copper nitrate solution, the silica sol and the polyethylene glycol solution is 1 g:10-15 ml:4-6 g:10-12 ml.

[0053] Preferably, the molecular weight distribution of polyethylene glycol is 2000-6000.

[0054] Preferably, the molecular sieve is ZSM-5 molecular sieve.

[0055] Preferably, the particle size distribution of the ZSM-5 molecular sieve is 3-5 μm.

[0056] By adopting the above technical solutions, first, the molecular sieve is preliminarily treated with copper nitrate. On the one hand, it enhances the adsorption active sites of the molecular sieve, greatly improving the adsorption capacity of the molecular sieve for acidic substances and sulfides in crude oil, which helps to destroy the stability of the oil-water interface and lay a good foundation for the subsequent demulsification process. On the other hand, the introduction of copper ions changes the charge distribution on the surface of the molecular sieve, making it more conducive to interacting with charged particles or polar molecules in crude oil, thereby improving the adsorption and coalescence efficiency of emulsion droplets and accelerating the overall demulsification process.

[0057] Secondly, coating with silica sol can form a protective film on the surface of the molecular sieve, which not only reduces the probability of the active sites being poisoned or blocked, ensuring the activity and stability of the molecular sieve over a long period of time, but also enhances the hydrophilicity of the molecular sieve, helps to destroy the water layer structure between oil droplets, increases the chance of oil droplets colliding and coalescing with each other, promotes oil-water separation, and improves the demulsification efficiency.

[0058] Finally, polyethylene glycol is coated on the surface of the molecular sieve with improved hydrophilicity. On the one hand, it can not only effectively isolate the molecular sieve structure from excessive erosion by acidic substances and sulfides, maintaining the stability of the molecular sieve structure, thus ensuring the lasting stability of the demulsification performance; it can also form a certain steric hindrance on the surface of the molecular sieve to prevent excessive aggregation of particles, making the molecular sieve more evenly distributed on the oil-water interface and improving the coverage and action efficiency on emulsion droplets; in addition, polyethylene glycol can also fine-tune the hydrophilicity and hydrophobicity of the molecular sieve, enabling the molecular sieve to maintain sufficient hydrophilicity to promote demulsification while avoiding the adverse effects caused by excessive hydrophilicity, such as loss in the aqueous phase and dissolution of copper ions, etc., which helps to reduce the risk of water pollution and achieve a green and efficient demulsification process.

[0059] Preferably, the demulsifier is compounded with polyacrylamide, and the amount of the polyacrylamide used is 2% to 4% of the mass of the demulsifier.

[0060] Preferably, the demulsifier and polyacrylamide are added in sequence with an interval of 25 to 35 minutes.

[0061] Preferably, the polyacrylamide is cationic polyacrylamide.

[0062] By adopting the above technical solution, the compound addition of polyacrylamide, during the demulsification process, on the one hand, polyacrylamide can effectively adsorb small water droplets and solid impurities in crude oil, such as silt, suspended matter, etc. This adsorption effect not only helps to purify crude oil, but also promotes small water droplets to gradually coalesce into large water droplets, thereby accelerating the separation between oil and water. On the other hand, polyacrylamide can also form a stable structure at the oil-water interface, which can prevent the separated oil and water from mixing again, that is, prevent the emulsion from re-emulsifying, and maintain the durability of the demulsification effect. In addition, in a complex crude oil system, due to the diverse components and large viscosity differences, demulsifiers are often difficult to distribute evenly. The addition of polyacrylamide can improve the fluidity of the system, making it easier for the demulsifier to diffuse and distribute in the crude oil, so that the demulsifier can more effectively contact and destroy the stability of the emulsion, thereby improving the demulsification efficiency.

[0063] In summary, this application has the following beneficial effects:

[0064] 1. This application adopts modified polyether and zwitterionic surfactants, and compounded with antacids, corrosion inhibitors and activated alumina to form a multifunctional demulsification and purification system. Aiming at the complex characteristics of high-sulfur and high-acid crude oil, it makes efforts in demulsification, acid resistance, corrosion inhibition, adsorption and purification, etc., to achieve efficient demulsification and purification of crude oil, and ensure the quality and stability of the front end of the crude oil processing industry chain.

[0065] 2. In this application, it is preferred to use modified polyether and zwitterionic surfactants both with comb-shaped structures, the side chains of which can interweave and cooperate with each other at the oil-water interface to form a more compact and orderly interface film. In addition, the molecules with comb-shaped structures can be more deeply inserted into the oil phase and the water phase by virtue of their multiple side chains, and interact with the complex components in the crude oil (such as asphaltenes, colloids, etc.), thereby helping to destroy the stable structure of the high-sulfur and high-acid crude oil emulsion, making it easier to separate into oil and water phases, thereby improving the demulsification effect.

[0066] 3. Preferably, the present application uses silica sol to coat activated alumina, which can improve the chemical stability, adsorption performance and dispersion performance of activated alumina, more comprehensively and effectively adsorb acidic substances, sulfides and emulsifiers (such as asphaltenes and resins) in high-sulfur and high-acid crude oil, reduce the influence of acidic substances and sulfides on the interfacial tension between the demulsifier and the oil-water interface, and at the same time destroy the originally stable emulsifier layer to enhance the demulsification effect. Detailed implementation manners

[0067] The following further elaborates on the present application in conjunction with embodiments.

[0068] Unless otherwise specified, the raw materials in the embodiments and comparative examples of the present application are all commercially available.

[0069] The silicone rubber defoamer was purchased from Dongguan Defeng Defoamer Co., Ltd.

[0070] The cationic polyacrylamide was purchased from Gongyi Yiyang Water Treatment Materials Co., Ltd.

[0071] The activated alumina was purchased from Hebei Yuehan Metal Materials Sales Co., Ltd.

[0072] 2,6-Diaminopyridine was purchased from Nantong Runfeng Petrochemical Co., Ltd.

[0073] 1-(3-Aminopropyl)imidazole was purchased from Hubei Xingdongcheng Chemical Co., Ltd.

[0074] Preparation Examples 1-3 of modified polyethers

[0075] Preparation Example 1

[0076] S11: Under a nitrogen atmosphere, add 20 g of diethylenetriamine, 2 g of potassium hydroxide, and 100 g of toluene into a reaction kettle equipped with a stirrer, a thermometer, and a pressure gauge. Start stirring at a speed of 500 r / min. After mixing evenly, heat up to 110°C at a rate of 5°C / min while controlling the pressure between 0.2 and 0.4 MPa. Add 10 g of propylene oxide into the reaction kettle in 6 equal portions, with an interval of 15 min between each addition. After each addition, maintain the reaction for 20 min. Then, introduce 30 g of ethylene oxide into the reaction kettle, with the feeding rate controlled between 0.5 and 1 g / min. After the introduction is completed, react for 90 min. Then, add 10 g of propylene oxide into the reaction kettle in 4 equal portions, with an interval of 15 min between each addition. After each addition, maintain the reaction for 15 min. Then, introduce 30 g of ethylene oxide into the reaction kettle again, with the feeding rate controlled between 1 and 1.5 g / min. After the introduction is completed, heat up to 120°C while controlling the pressure between 0.3 and 0.5 MPa, and react for 70 min. After the reaction is completed, first cool naturally to room temperature, distill at 100°C under a pressure between 0.03 and 0.05 MPa for 120 min, then add deionized water equal to 50% of the total mass of the product, stir well, let it stand for layering, take the organic phase, repeat 3 times, and then filter through a 0.5-μm filter membrane to obtain a polyether intermediate in a comb-like structure;

[0077] S12: Under a nitrogen atmosphere, add the polyether intermediate and 50 g of toluene into the reaction kettle. Start stirring at a speed of 400 r / min, then add 3.15 g of triethylamine, and continue stirring for 15 min. Slowly dropwise add 5 g of allyl sulfonic acid lactone, with the dropping time controlled between 30 and 40 min. Stir and mix for 15 min, heat up to 90°C at a rate of 5°C, react for 4 h, measure the acid value of the product, continue the reaction for 30 min, and measure the acid value of the product again. When the acid value no longer changes, stop the reaction, cool naturally to room temperature, distill at 100°C under a pressure between 0.03 and 0.05 MPa for 90 min, then add deionized water equal to 1 time the mass of the product, stir well, let it stand for layering, take the organic phase, repeat 3 times, and then filter through a 0.5-μm filter membrane to obtain a modified polyether.

[0078] Among them, ethylene oxide is introduced after being liquefied, and the liquefaction temperature is 3°C.

[0079] Preparation Example 2

[0080] S11: Under a nitrogen atmosphere, add 10 g of diethylenetriamine, 5 g of triethylenetetramine, 1 g of potassium hydroxide, and 100 g of toluene into a reaction kettle equipped with a stirrer, a thermometer, and a pressure gauge. Start stirring at a speed of 500 r / min. After mixing evenly, heat up to 130 °C at a rate of 5 °C / min while controlling the pressure between 0.2 and 0.4 MPa. Add 7.5 g of propylene oxide into the reaction kettle in 4 equal portions at intervals of 15 min. After each addition, maintain the reaction for 15 min. Then, introduce 35 g of ethylene oxide into the reaction kettle at a rate controlled between 0.5 and 1 g / min. After the introduction is completed, react for 60 min. Then, add 7.5 g of propylene oxide into the reaction kettle in 2 equal portions at intervals of 15 min. After each addition, maintain the reaction for 10 min. Then, introduce 35 g of ethylene oxide into the reaction kettle at a rate controlled between 1 and 1.5 g / min. After the introduction is completed, heat up to 140 °C while controlling the pressure between 0.3 and 0.5 MPa and react for 50 min. After the reaction is completed, first cool naturally to room temperature, distill for 120 min at 100 °C under a pressure between 0.03 and 0.05 MPa, then add deionized water equal to 50% of the total mass of the product, stir well, let it stand for layering, take the organic phase, repeat 3 times, and then filter through a 0.5-μm filter membrane to obtain a polyether intermediate in a comb-like structure;

[0081] S12: Under a nitrogen atmosphere, add the polyether intermediate and 50 g of toluene into the reaction kettle. Start stirring at a speed of 400 r / min, then add 1.15 g of triethylamine, and continuously stir for 15 min. Slowly dropwise add 15 g of allyl sulfonic acid lactone, and control the dropping time between 20 and 25 min. Stir and mix for 15 min, heat up to 110 °C at a rate of 5 °C / min, react for 2 h, measure the acid value of the product, continue to react for 40 min, measure the acid value of the product again. When the acid value no longer changes, stop the reaction, cool naturally to room temperature, distill for 90 min at 100 °C under a pressure between 0.03 and 0.05 MPa, then add deionized water equal to 1 times the mass of the product, stir well, let it stand for layering, take the organic phase, repeat 3 times, and then filter through a 0.5-μm filter membrane to obtain a modified polyether.

[0082] Among them, ethylene oxide is introduced after being liquefied, and the liquefaction temperature is 3 °C.

[0083] Preparation Example 3

[0084] S11: Under a nitrogen atmosphere, add 10 g of diethylenetriamine, 8 g of triethylenetetramine, 1.5 g of potassium hydroxide, and 100 g of toluene into a reaction kettle equipped with a stirrer, a thermometer, and a pressure gauge. Start stirring at a speed of 500 r / min. After mixing evenly, heat up to 120 °C at a rate of 5 °C / min, and at the same time control the pressure between 0.2 and 0.4 MPa. Add 8.5 g of propylene oxide into the reaction kettle in 5 equal portions, with an interval of 10 min between each addition. After each addition, maintain the reaction for 18 min. Then, introduce 32.5 g of ethylene oxide into the reaction kettle, control the feeding rate between 0.5 and 1 g / min. After the feeding is completed, react for 80 min, and then add 8.5 g of propylene oxide into the reaction kettle in 3 equal portions, with an interval of 15 min between each addition. After each addition, maintain the reaction for 13 min. Then, introduce 32.5 g of ethylene oxide into the reaction kettle again, control the feeding rate between 1 and 1.5 g / min. After the feeding is completed, heat up to 130 °C, and at the same time control the pressure between 0.3 and 0.5 MPa. React for 60 min. After the reaction is completed, first cool naturally to room temperature, and then distill at 100 °C under a pressure between 0.03 and 0.05 MPa for 120 min. Then, add deionized water with a mass of 50% of the total product mass, stir well, let it stand for stratification, take the organic phase, repeat 3 times, and then filter through a 0.5-μm filter membrane to obtain a polyether intermediate in a comb-like structure;

[0085] S12: Under a nitrogen atmosphere, add the polyether intermediate and 50 g of toluene into the reaction kettle. Start stirring at a speed of 400 r / min, then add 2.2 g of triethylamine, and continue stirring for 15 min. Slowly dropwise add 10 g of allyl sulfonic acid lactone, and control the dropping time between 15 and 20 min. Stir and mix for 15 min, heat up to 100 °C at a rate of 5 °C / min, react for 3 h, measure the acid value of the product, continue the reaction for 30 min, measure the acid value of the product again. When the acid value no longer changes, stop the reaction, cool naturally to room temperature, and then distill at 100 °C under a pressure between 0.03 and 0.05 MPa for 90 min. Then, add deionized water with a mass 1 time that of the product, stir well, let it stand for stratification, take the organic phase, repeat 3 times, and then filter through a 0.5-μm filter membrane to obtain a modified polyether.

[0086] Among them, ethylene oxide is introduced after being liquefied, and the liquefaction temperature is 3 °C.

[0087] Preparation Examples 4-6 Zwitterionic Surfactants

[0088] Preparation Example 4

[0089] 28.2 g of oleic acid, 10.9 g of 2,6-diaminopyridine, 100 g of toluene and 0.4 g of butylated hydroxyanisole were added to a reaction kettle equipped with a stirrer and a thermometer. Stirring was started at a speed of 300 r / min, and the mixture was stirred for 20 min. Under a nitrogen atmosphere, the temperature was slowly raised to 100 °C. After adding 1.2 g of p-toluenesulfonic acid, the reaction was carried out for 4 h to obtain an intermediate. The temperature was lowered to 70 °C, and a mixture of 9.2 g of polyethylene glycol glycidyl ether and 7.7 g of polypropylene glycol glycidyl ether and 0.25 g of triethylamine were slowly added dropwise with stirring. After the addition was completed, the reaction was carried out for 5 h. The temperature was lowered to 60 °C, 3.4 g of leaf alcohol and 0.17 g of azobisisobutyronitrile were added, and the reaction was carried out for 3.5 h. Then 5.3 g of monobutyl maleate was added, and the mixture was stirred evenly. After continuing the reaction for 4 h, it was naturally cooled to room temperature. Water equal to 60% of the product mass and ethanol equal to 40% of the product mass were added, and then the pH was adjusted to neutral with 10% sodium hydroxide by mass. Then it was transferred to a separatory funnel and allowed to stand for layering. The organic phase was taken and dried with anhydrous sodium sulfate, and the desiccant was removed by filtration. Then, at 70 °C and a pressure between 3 and 4 kPa, distillation was carried out for 2 h to obtain an amphoteric ionic surfactant with a comb-shaped structure.

[0090] Among them, the molar mass of oleic acid is 282 g / mol, and the dosage is 0.1 mol; the molar mass of 2,6-diaminopyridine is 109 g / mol, and the dosage is 0.1 mol; the molar mass of leaf alcohol is 100 g / mol, and the dosage is 0.034 mol; the molar mass of monobutyl maleate is 172 g / mol, and the dosage is 0.031 mol.

[0091] Preparation Example 5

[0092] 28.2 g of oleic acid, 8.7 g of 2,6-diaminopyridine, 5 g of 1-(3-aminopropyl)imidazole, 100 g of toluene and 0.2 g of butylated hydroxyanisole were added to a reaction kettle equipped with a stirrer and a thermometer. Stirring was started at a speed of 300 r / min, and the mixture was stirred for 20 min. Under a nitrogen atmosphere, the temperature was slowly raised to 120 °C. After adding 0.4 g of p-toluenesulfonic acid, the reaction was carried out for 2 h to obtain an intermediate. The temperature was lowered to 90 °C, and a mixture of 13.5 g of polyethylene glycol glycidyl ether and 9.0 g of polypropylene glycol glycidyl ether and 0.11 g of triethylamine were slowly added dropwise with stirring. After the addition was completed, the reaction was carried out for 3 h. The temperature was lowered to 80 °C, 5.1 g of leaf alcohol and 0.15 g of azobisisobutyronitrile were added, and the reaction was carried out for 2 h. Then 9.6 g of monobutyl maleate was added, and the mixture was stirred evenly and the reaction was continued for 4 h. Then it was naturally cooled to room temperature, water equal to 60% of the product mass and ethanol equal to 40% of the product mass were added, and then the pH was adjusted to neutral with 10% sodium hydroxide by mass fraction. Then it was transferred to a separatory funnel, allowed to stand and layer, and the organic phase was taken and dried with anhydrous sodium sulfate. The desiccant was removed by filtration, and then distilled at 70 °C under a pressure between 3 and 4 kPa for 2 h to obtain an amphoteric ionic surfactant with a comb-like structure.

[0093] Among them, the molar mass of oleic acid is 282 g / mol, and the dosage is 0.1 mol; the molar mass of 2,6-diaminopyridine is 109 g / mol, and the dosage is 0.08 mol; the molar mass of 1-(3-aminopropyl)imidazole is 125 g / mol, and the dosage is 0.04 mol; the molar mass of leaf alcohol is 100 g / mol, and the dosage is 0.051 mol; the molar mass of monobutyl maleate is 172 g / mol, and the dosage is 0.056 mol.

[0094] Preparation Example 6

[0095] 28.2 g of oleic acid, 5.5 g of 2,6-diaminopyridine, 7.5 g of 1-(3-aminopropyl)imidazole, 100 g of toluene and 0.32 g of butylated hydroxyanisole were added to a reaction kettle equipped with a stirrer and a thermometer. Stirring was started at a speed of 300 r / min, and the mixture was stirred for 20 min. Under a nitrogen atmosphere, the temperature was slowly raised to 110 °C. After adding 0.8 g of p-toluenesulfonic acid, the reaction was carried out for 3 h to obtain an intermediate. The temperature was lowered to 80 °C, and a mixture of 11.2 g of polyethylene glycol glycidyl ether and 8.6 g of polypropylene glycol glycidyl ether and 0.2 g of triethylamine were slowly added dropwise with stirring. After the addition was completed, the reaction was carried out for 4 h. The temperature was lowered to 70 °C, 4.5 g of leaf alcohol and 0.18 g of azobisisobutyronitrile were added, and the reaction was carried out for 3 h. Then 7.7 g of monobutyl maleate was added, and the mixture was stirred evenly. After continuing the reaction for 3 h, it was naturally cooled to room temperature. Water equal to 60% of the product mass and ethanol equal to 40% of the product mass were added. Then, the pH was adjusted to neutral with 10% sodium hydroxide by mass fraction, and then transferred to a separatory funnel and allowed to stand for stratification. The organic phase was taken and dried with anhydrous sodium sulfate, and the desiccant was removed by filtration. Then, distillation was carried out at 70 °C under a pressure between 3 and 4 kPa for 2 h to obtain an amphoteric ionic surfactant with a comb-like structure.

[0096] Among them, the molar mass of oleic acid is 282 g / mol, and the dosage is 0.1 mol; the molar mass of 2,6-diaminopyridine is 109 g / mol, and the dosage is 0.05 mol; the molar mass of 1-(3-aminopropyl)imidazole is 125 g / mol, and the dosage is 0.06 mol; the molar mass of leaf alcohol is 100 g / mol, and the dosage is 0.045 mol; the molar mass of monobutyl maleate is 172 g / mol, and the dosage is 0.045 mol.

[0097] Example 1

[0098] This example provides a preparation method of a demulsifier for high-sulfur and high-acid crude oil, which includes the following steps:

[0099] At 30 °C, 40 g of modified polyether and 25 g of amphoteric ionic surfactant were added to a reaction kettle equipped with a stirrer, a thermometer and a reflux condenser. Stirring was started at a speed of 300 r / min, and the mixture was stirred for 15 min. After slowly adding 10 g of toluene, stirring was continued for 20 min, and then the temperature was raised to 50 °C. First, 3 g of activated alumina was added and stirred evenly, then 5 g of ethanolamine, 3 g of zinc oxide and 2 g of oleic acid imidazoline were added, and the mixture was stirred for 40 min. Finally, 0.5 g of silicone rubber defoamer was added, the stirring speed was adjusted to 200 r / min, and stirring was continued for 10 min. It was naturally cooled to room temperature, and the reaction product was transferred to a separatory funnel and allowed to stand for stratification. The upper clear liquid was taken and filtered to obtain the demulsifier.

[0100] Among them, the particle size distribution of zinc oxide is 50 - 100 nm; before adding zinc oxide, 15 ml of sodium dodecylbenzenesulfonate with a mass fraction of 1% was stirred and mixed evenly with zinc oxide;

[0101] The particle size distribution of activated alumina is 1 - 10 μm; before adding activated alumina, 15 ml of sodium dodecylbenzenesulfonate with a mass fraction of 1% was stirred and mixed evenly with activated alumina.

[0102] The modified polyether is from Preparation Example 1; the zwitterionic surfactant is from Preparation Example 4.

[0103] Example 2

[0104] This example provides a preparation method of a demulsifier for high - sulfur and high - acid crude oil, including the following steps:

[0105] At 40 °C, 60 g of modified polyether and 30 g of zwitterionic surfactant were added to a reaction kettle equipped with a stirrer, a thermometer, and a reflux condenser. Stirring was started at a speed of 300 r / min and stirred and mixed for 15 min. After slowly adding 12 g of toluene, stirring and mixing continued for 20 min, then the temperature was raised to 70 °C. First, 8 g of activated alumina was added and stirred and mixed evenly, then 10 g of ethanolamine, 6 g of zinc oxide, and 4 g of oleic acid imidazoline were added, stirred and mixed for 40 min. Finally, 1 g of silicone rubber defoamer was added, the stirring speed was adjusted to 200 r / min, and stirring and mixing continued for 10 min. It was naturally cooled to room temperature, the reaction product was transferred to a separatory funnel, allowed to stand for stratification, and the upper clear liquid was taken and filtered to obtain the demulsifier.

[0106] Among them, the particle size distribution of zinc oxide is 50 - 100 nm; before adding zinc oxide, 25 ml of sodium dodecylbenzenesulfonate with a mass fraction of 1% was stirred and mixed evenly with zinc oxide;

[0107] The particle size distribution of activated alumina is 1 - 10 μm; before adding activated alumina, it was subjected to the following pretreatment steps:

[0108] 5 ml of tetraethyl orthosilicate, 20 ml of ethanol, and 40 ml of water were mixed evenly, and the pH was adjusted to between 2 - 3 with 10% dilute hydrochloric acid by mass fraction, the temperature was raised to 35 °C, and stirring reaction continued for 8 h, then cooled down to obtain silica sol;

[0109] Take 30 g of silica sol, add 10 g of activated alumina and mix evenly, let it stand for 16 h, filter, place it at room temperature for 12 h, at 50 °C, age for 4 h, dry, and then at 400 °C, with a heating rate of 5 - 10 °C / min, calcine for 4 h to obtain;

[0110] The modified polyether is from Preparation Example 1; the zwitterionic surfactant is from Preparation Example 4.

[0111] Example 3

[0112] This example provides a preparation method of a demulsifier for high-sulfur and high-acid crude oil, including the following steps:

[0113] At 35 °C, add 50 g of modified polyether and 28 g of zwitterionic surfactant into a reaction kettle equipped with a stirrer, a thermometer, and a reflux condenser. Start stirring at a speed of 300 r / min and stir and mix for 15 min. After slowly adding 10 g of toluene, continue to stir and mix for 20 min, then raise the temperature to 60 °C. First, add 6 g of activated alumina and stir and mix evenly, then add 7 g of ethanolamine, 4 g of zinc oxide, and 3 g of oleic acid imidazoline, stir and mix for 40 min. Finally, add 0.8 g of silicone rubber defoamer, adjust the stirring speed to 200 r / min, continue to stir and mix for 10 min, and naturally cool to room temperature. Transfer the reaction product to a separating funnel, let it stand for stratification, take the upper clear liquid, and filter to obtain the demulsifier.

[0114] Among them, the particle size distribution of zinc oxide is 50 - 100 nm; before adding zinc oxide, it is stirred and mixed evenly with 15 ml of sodium dodecylbenzenesulfonate with a mass fraction of 1%;

[0115] The particle size distribution of activated alumina is 1 - 10 μm; before adding activated alumina, it undergoes the following pretreatment steps:

[0116] Mix 5 ml of tetraethyl orthosilicate, 40 ml of ethanol, and 20 ml of water evenly, adjust the pH to between 2 - 3 with 10% dilute hydrochloric acid, raise the temperature to 55 °C, continuously stir and react for 3 h, then cool down to obtain silica sol;

[0117] Take 50 g of silica sol, add 10 g of activated alumina and mix evenly, let it stand for 24 h, filter, place it at room temperature for 12 h, at 50 °C, age for 6 h, dry, and then at 500 °C, with a heating rate of 5 - 10 °C / min, calcine for 2 h to obtain it;

[0118] The modified polyether is from Preparation Example 1; the zwitterionic surfactant is from Preparation Example 4.

[0119] Example 4

[0120] The difference between this example and Example 3 is that:

[0121] The particle size distribution of activated alumina is 1 - 10 μm; before adding activated alumina, it undergoes the following pretreatment steps:

[0122] Mix 5 ml of tetraethyl orthosilicate, 30 ml of ethanol and 30 ml of water uniformly, adjust the pH to between 2 and 3 with 10% dilute hydrochloric acid by mass fraction, raise the temperature to 45 °C, continuously stir and react for 4.5 h, then cool down to obtain silica sol;

[0123] Take 40 g of silica sol, add 10 g of activated alumina and mix uniformly, let stand for 20 h, filter, place at room temperature for 12 h, age at 50 °C for 5 h, dry, and then calcine at 450 °C with a heating rate of 5 - 10 °C / min for 3 h to obtain;

[0124] The modified polyether is from Preparation Example 2; the zwitterionic surfactant is from Preparation Example 5.

[0125] Others are the same as in Example 3.

[0126] Example 5

[0127] The difference between this example and Example 4 is that:

[0128] The modified polyether is from Preparation Example 3; the zwitterionic surfactant is from Preparation Example 6.

[0129] Others are the same as in Example 4.

[0130] Example 6

[0131] The difference between this example and Example 5 is that:

[0132] While adding activated alumina, 2 g of ZSM-5 molecular sieve is also added. Before use, the molecular sieve undergoes the following pretreatment steps:

[0133] (1) Add 5 g of ZSM-5 molecular sieve to 50 ml of copper nitrate solution with a concentration of 0.2 mol / L, mix uniformly, raise the temperature to 40 °C, stir and mix for 24 h at a rotation speed of 150 r / min, filter, rinse 2 times with deionized water at 10 °C, with a dosage of 10 ml each time, and dry to constant weight at 60 °C to obtain the preliminarily treated molecular sieve;

[0134] (2) Mix 5 ml of tetraethyl orthosilicate, 20 ml of ethanol and 40 ml of water uniformly, adjust the pH to 2 - 3, raise the temperature to 35 °C, react for 8 h to obtain silica sol; take 40 g of silica sol and add the preliminarily treated molecular sieve, stir and mix at room temperature for 60 min, let stand for 16 h, filter, place at room temperature for 12 h, dry to constant weight at 60 °C, and then sinter at 400 °C for 4 h, cool down to obtain the preliminarily coated molecular sieve;

[0135] (3) Add the preliminarily coated molecular sieve into 50 ml of a 6% polyethylene glycol solution, mix evenly, heat up to 45 °C, stir and mix for 8 h, filter, rinse twice with deionized water at 20 °C, with a dosage of 10 ml each time, and dry to constant weight at 50 °C to obtain the product.

[0136] Others are the same as in Example 5.

[0137] Example 7

[0138] The difference between this example and Example 5 is that:

[0139] While adding activated alumina, 5 g of ZSM-5 molecular sieve is also added. Before use, the molecular sieve undergoes the following pretreatment steps:

[0140] (1) Add 5 g of ZSM-5 molecular sieve into 75 ml of a 0.4 mol / L copper nitrate solution, mix evenly, heat up to 60 °C, stir and mix for 18 h at a rotation speed of 150 r / min, filter, rinse twice with deionized water at 10 °C, with a dosage of 10 ml each time, and dry to constant weight at 60 °C to obtain the preliminarily treated molecular sieve;

[0141] (2) Mix 5 ml of tetraethyl orthosilicate, 40 ml of ethanol and 20 ml of water evenly, adjust the pH to 2 - 3, heat up to 55 °C, react for 3 h to obtain silica sol; Take 60 g of silica sol and add it to the preliminarily treated molecular sieve, stir and mix at room temperature for 60 min, let it stand for 24 h, filter, place it at room temperature for 12 h, dry to constant weight at 60 °C, and then sinter at 500 °C for 3 h, cool down to obtain the preliminarily coated molecular sieve;

[0142] (3) Add the preliminarily coated molecular sieve into 60 ml of an 8% polyethylene glycol solution, mix evenly, heat up to 65 °C, stir and mix for 6 h, filter, rinse twice with deionized water at 20 °C, with a dosage of 10 ml each time, and dry to constant weight at 50 °C to obtain the product.

[0143] Others are the same as in Example 5.

[0144] Example 8

[0145] The difference between this example and Example 5 is that:

[0146] While adding activated alumina, 4 g of ZSM-5 molecular sieve is also added. Before use, the molecular sieve undergoes the following pretreatment steps:

[0147] (1) Add 5 g of ZSM-5 molecular sieve to 60 ml of copper nitrate solution with a concentration of 0.3 mol / L, mix evenly, heat up to 50 °C, stir and mix for 20 h at a rotation speed of 150 r / min, filter, wash twice with deionized water at 10 °C, with a dosage of 10 ml each time, and dry to constant weight at 60 °C to obtain the preliminarily treated molecular sieve;

[0148] (2) Mix 5 ml of tetraethyl orthosilicate, 30 ml of ethanol and 30 ml of water evenly, adjust the pH to 2 - 3, heat up to 45 °C, and after reacting for 4.5 h, obtain silica sol; Take 50 g of silica sol and add it to the preliminarily treated molecular sieve, stir and mix at room temperature for 60 min, let it stand for 20 h, filter, place it at room temperature for 12 h, dry to constant weight at 60 °C, and then sinter at 450 °C for 3.5 h, cool down to obtain the preliminarily coated molecular sieve;

[0149] (3) Add the preliminarily coated molecular sieve to 50 ml of polyethylene glycol solution with a concentration of 7%, mix evenly, heat up to 55 °C, stir and mix for 7 h, filter, wash twice with deionized water at 20 °C, with a dosage of 10 ml each time, and dry to constant weight at 50 °C to obtain the product.

[0150] Others are the same as in Example 5.

[0151] Comparative Example 1

[0152] The difference between this comparative example and Example 1 is that:

[0153] The modified polyether is a common polyether, and the preparation method of the common polyether includes the following steps:

[0154] S11: Under a nitrogen atmosphere, add 20 g of diethylenetriamine, 2 g of potassium hydroxide and 100 g of toluene to a reaction kettle equipped with a stirrer, a thermometer and a pressure gauge, start stirring at a rotation speed of 500 r / min, after mixing evenly, heat up to 110 °C at a rate of 5 °C / min, while controlling the pressure between 0.4 - 0.6 MPa, first add 20 g of propylene oxide to the reaction kettle at a rate of 2 - 3 g / min, and then add 60 g of ethylene oxide to the reaction kettle at a rate of 3 - 4 g / min, after reacting for 4 h, naturally cool to room temperature, at 100 °C and a pressure between 0.03 - 0.05 MPa, distill for 120 min, then add deionized water accounting for 50% of the total mass of the product, stir well, let it stand and separate layers, take the organic phase, repeat 3 times, and then filter with a 0.5 μm filter membrane to obtain the polyether intermediate;

[0155] S12: Under a nitrogen atmosphere, add the polyether intermediate and 50 g of toluene into the reaction kettle, start stirring at a stirring speed of 400 r / min, then add 3.15 g of triethylamine, continue stirring for 15 min, slowly dropwise add 5 g of allyl sulfonic acid lactone, control the dropping time between 30 and 40 min, stir and mix for 15 min, heat up to 90 °C at a rate of 5 °C, react for 4 h, measure the acid value of the product, continue reacting for 30 min, measure the acid value of the product again, stop the reaction when the acid value no longer changes, naturally cool to room temperature, distill at 100 °C under a pressure between 0.03 and 0.05 MPa for 90 min, then add deionized water in an amount 1 time the mass of the product, fully stir, let it stand for layering, take the organic phase, repeat 3 times, and then filter through a 0.5-μm filter membrane to obtain the ordinary polyether.

[0156] Among them, ethylene oxide is introduced after being liquefied, and the liquefaction temperature is 3 °C.

[0157] Others are the same as in Example 1.

[0158] Comparative Example 2

[0159] The preparation method of the modified polyether includes the following steps:

[0160] Under a nitrogen atmosphere, add 20 g of diethylenetriamine, 2 g of potassium hydroxide and 100 g of toluene into the reaction kettle equipped with a stirrer, a thermometer and a pressure gauge, start stirring at a rotation speed of 500 r / min, after mixing evenly, heat up to 110 °C at a rate of 5 °C / min, and at the same time control the pressure between 0.2 and 0.4 MPa, add 10 g of propylene oxide into the reaction kettle in 6 equal amounts at intervals of 15 min, after each feeding, keep reacting for 20 min; then introduce 30 g of ethylene oxide into the reaction kettle, control the feeding rate between 0.5 and 1 g / min, after the feeding is completed, react for 90 min, then add 10 g of propylene oxide into the reaction kettle in 4 equal amounts at intervals of 15 min, after each feeding, keep reacting for 15 min; then introduce 30 g of ethylene oxide into the reaction kettle, control the feeding rate between 1 and 1.5 g / min, after the feeding is completed, heat up to 120 °C, and at the same time control the pressure between 0.3 and 0.5 MPa, react for 70 min, after the reaction is completed, first naturally cool to room temperature, distill at 100 °C under a pressure between 0.03 and 0.05 MPa for 120 min, then add deionized water in an amount of 50% of the total mass of the product, fully stir, let it stand for layering, take the organic phase, repeat 3 times, and then filter through a 0.5-μm filter membrane to obtain the modified polyether.

[0161] Others are the same as in Example 1.

[0162] Comparative Example 3

[0163] The difference between this comparative example and Example 1 is:

[0164] Preparation method of zwitterionic surfactant, comprising the following steps:

[0165] Add 28.2 g of oleic acid, 10.5 g of diethanolamine, 100 g of toluene and 0.4 g of butylated hydroxyanisole into a reaction kettle equipped with a stirrer and a thermometer, start stirring at a speed of 300 r / min, stir and mix for 20 min, under a nitrogen atmosphere, slowly heat up to 100 °C, after dropping 1.2 g of p-toluenesulfonic acid, react for 4 h to obtain an intermediate; cool down to 70 °C, slowly dropwise add a mixture of 9.2 g of polyethylene glycol glycidyl ether and 7.7 g of polypropylene glycol glycidyl ether and 0.25 g of triethylamine under stirring, after the dropping is completed, react for 5 h, cool down to 60 °C, add 3.4 g of leaf alcohol and 0.17 g of azobisisobutyronitrile, react for 3.5 h, then add 5.3 g of monobutyl maleate, mix evenly, continue to react for 4 h, then naturally cool to room temperature, add water with a mass of 60% of the product and ethanol with a mass of 40% of the product, then adjust the pH to neutral with 10% sodium hydroxide by mass fraction, then transfer to a separatory funnel, let it stand and separate layers, take the organic phase and dry it with anhydrous sodium sulfate, filter to remove the desiccant, then distill at 70 °C under a pressure between 3 and 4 kPa for 2 h to obtain a zwitterionic surfactant with a comb-shaped structure.

[0166] Among them, the molar mass of oleic acid is 282 g / mol, and the dosage is 0.1 mol; the molar mass of diethanolamine is 105 g / mol, and the dosage is 0.1 mol; the molar mass of leaf alcohol is 100 g / mol, and the dosage is 0.034 mol; the molar mass of monobutyl maleate is 172 g / mol, and the dosage is 0.031 mol.

[0167] Others are the same as in Example 1.

[0168] Comparative Example 4

[0169] The difference between this comparative example and Example 1 is:

[0170] Preparation method of zwitterionic surfactant, comprising the following steps:

[0171] Add 28.2 g of oleic acid, 10.9 g of 2,6-diaminopyridine, 100 g of toluene, and 0.4 g of butylated hydroxyanisole into a reaction kettle equipped with a stirrer and a thermometer. Start stirring at a speed of 300 r / min and stir and mix for 20 min. Under a nitrogen atmosphere, slowly heat up to 100 °C. After dropping 1.2 g of p-toluenesulfonic acid, react for 4 h to obtain an intermediate; cool down to 60 °C, add 3.4 g of leaf alcohol and 0.17 g of azobisisobutyronitrile, react for 3.5 h, then add 5.3 g of monobutyl maleate, mix evenly, continue to react for 4 h, then naturally cool to room temperature, add water with a mass of 60% of the product and ethanol with a mass of 40% of the product, then adjust the pH to neutral with 10% sodium hydroxide by mass, then transfer to a separatory funnel, let it stand for layering, take the organic phase and dry it with anhydrous sodium sulfate, filter to remove the desiccant, and then distill at 70 °C under a pressure between 3 and 4 kPa for 2 h to obtain an amphoteric surfactant.

[0172] Among them, the molar mass of oleic acid is 282 g / mol and the dosage is 0.1 mol; the molar mass of 2,6-diaminopyridine is 109 g / mol and the dosage is 0.1 mol; the molar mass of leaf alcohol is 100 g / mol and the dosage is 0.034 mol; the molar mass of monobutyl maleate is 172 g / mol and the dosage is 0.031 mol.

[0173] Others are the same as in Example 1.

[0174] Performance detection

[0175] Test raw material: In a certain high-sulfur and high-acid crude oil from Qilu Petrochemical's Shengli Refinery, the sulfur content is about 2.7%, the mercaptan content is moderate, the proportion of thiophene and its derivatives is relatively high, the acid value is about 1.9 mgKOH / g, mainly naphthenic acid, among which, the proportion of heavy components such as asphaltene and gum is about 30.8%, at 20 °C, the density is about 0.935 g / cm 3 , and the water content is about 29.6%.

[0176] (1) Detection 1

[0177] At 20 °C, take the above-mentioned high-sulfur and high-acid crude oil to prepare 12 samples, sequentially labeled as Sample 1-12, with a dosage of 200 g of high-sulfur and high-acid crude oil for each sample. After adding the demulsifiers prepared in Examples 1-8 and Comparative Examples 1-4 according to a dosage of 30 ppm respectively, stir and mix evenly at a speed of 300 r / min. Take 30 ml of samples at specified time intervals and transfer them to centrifuge tubes. Put the centrifuge tubes into a centrifuge and centrifuge at 3000 r / min for 15 min to fully separate the oil phase and the water phase. After the separation is completed, measure the volume of the lower water phase, and according to the water density of 1 g / cm 3 , calculate the water mass, and then calculate the dehydration rate. The results are shown in Table 1.

[0178] Table 1 Performance test data of demulsifiers prepared in Examples 1-8 and Comparative Examples 1-4

[0179]

[0180] (2) Test Two

[0181] At 20 °C, take the above high-sulfur and high-acid crude oil to prepare 2 samples, which are marked as Sample 13 and Sample 14 in sequence. The amount of high-sulfur and high-acid crude oil used for each sample is 200 g. After adding the demulsifier prepared in Example 7 at a dosage of 30 ppm respectively, stir and mix at a speed of 300 r / min for about 25-30 min, then add cationic polyacrylamide accounting for 2% of the demulsifier dosage and cationic polyacrylamide accounting for 4% of the demulsifier dosage respectively, stir and mix evenly, and take 30 ml of samples at specified time intervals and transfer them to centrifuge tubes. Place the centrifuge tubes in a centrifuge and centrifuge at 3000 r / min for 15 min to fully separate the oil phase and the water phase. After the separation is completed, measure the volume of the lower water phase, and calculate the water mass according to the water density of 1 g / cm 3 , and calculate the dehydration rate. The results are shown in Table 2.

[0182] Table 2 Performance test data after the compound use of Example 7 and cationic polyacrylamide

[0183]

[0184] (3) Test Three

[0185] After 90 min of sedimentation dehydration, the sulfur content and acid value of the separated oil phases of Sample 7 corresponding to Example 7 in Test One and Sample 13 corresponding to Example 7 in Test Two are detected respectively. The test results are shown in Table 3.

[0186] Table 3 Detection data of sulfur content and acid value in the oil phases of Sample 7 and Sample 13

[0187]

[0188] From the performance test data of the demulsifiers prepared in Examples 1-8 and Comparative Examples 1-4, as shown in Table 1, it can be seen that:

[0189] First of all, the modified polyether with a comb-like structure and the zwitterionic surfactant with a comb-like structure can quickly and effectively promote the coalescence of tiny water droplets, enabling the preliminary separation of the water phase from the oil phase. Their interaction with other components in the crude oil can not only reduce the stabilizing effect of these components on emulsification, but also form a more stable adsorption layer at the oil-water interface, preventing the separated water droplets from returning to the oil phase again, and greatly improving the dehydration rate of the crude oil.

[0190] Secondly, through the pretreatment of activated alumina, the dispersion performance and adsorption performance of activated alumina in the crude oil system are improved, effectively destroying the originally stable emulsifier layer, thereby enhancing the demulsification effect.

[0191] Finally, by adding the pretreated molecular sieve, the molecular sieve can quickly adsorb small molecule impurities in the crude oil system, creating an effective working space at the oil-water interface for the demulsifier, thereby further increasing the dehydration rate of the crude oil.

[0192] From the analysis of the data in Table 2, it can be seen that when cationic polyacrylamide is used in combination with the demulsifier in Example 7, the cationic polyacrylamide starts to play a flocculation role in the initial stage, enabling the water droplets separated by the demulsifier to aggregate and settle faster, preventing the re-emulsification of the emulsion, thereby improving the overall dehydration efficiency.

[0193] From the analysis of the data in Table 3, it can be seen that while the demulsifier prepared in Example 7 demulsifies, it can effectively reduce the sulfur content and acid value in the crude oil system. This is the result of the combined action of the demulsification effect of the demulsifier itself and the components such as cationic polyacrylamide. These action mechanisms cooperate with each other to improve the quality of the crude oil, providing favorable conditions for subsequent crude oil processing and product quality improvement.

[0194] This specific embodiment is only an explanation of the present application and does not limit the present application. After reading this specification, those skilled in the art can make modifications to this embodiment without creative contributions as needed, but as long as it is within the scope of the claims of the present application, it is protected by the patent law.

Claims

1. A method for preparing a high-sulfur and high-acid crude oil demulsifier, characterized in that: The steps include: 40-60 parts by weight of modified polyether, 25-30 parts by weight of zwitterionic surfactant and 10-12 parts by weight of solvent are mixed evenly, heated to 50-70° C., 3-8 parts by weight of activated alumina, 8-16 parts by weight of antacid and 2-4 parts by weight of corrosion inhibitor are added, mixed evenly, 0.5-1 parts by weight of defoamer are added, mixed evenly, cooled, and allowed to stand for stratification to obtain a demulsifier; The antacids include ethanolamine and zinc oxide; The preparation method of the modified polyether comprises the following steps: S11: Under an inert atmosphere, polyethylene polyamine, catalyst A and solvent are mixed uniformly in a reactor, heated to 110-130°C, and then a portion of propylene oxide is added to the reactor in 4-6 times, and each time it is added, the reaction is carried out for 15-20 minutes; then a portion of ethylene oxide is added to the reactor, and the reaction is carried out for 60-90 minutes, and another portion of propylene oxide is added to the reactor in 2-4 times, and each time it is added, the reaction is carried out for 10-15 minutes, and then another portion of ethylene oxide is added to the reactor, and the temperature is raised to 120-140°C, and after reacting for 50-70 minutes, the temperature is lowered, distilled, and washed to obtain a polyether intermediate with a comb-shaped structure; S12: Under an inert atmosphere, the polyether intermediate, catalyst B, solvent and allyl sultone are mixed uniformly in a reactor, the temperature is raised to 90-110° C., the reaction is carried out for 2-4 hours, the temperature is lowered, distilled and washed to obtain a modified polyether.

2. The method for preparing the high-sulfur and high-acid crude oil demulsifier according to claim 1, characterized in that The mass ratio of the polyethylene polyamine, propylene oxide and ethylene oxide is (15-20): (15-20): (60-70); the amount of the allyl sultone is 5%-15% of the total mass of the polyethylene polyamine, propylene oxide and ethylene oxide.

3. The method for preparing the high-sulfur and high-acid crude oil demulsifier according to claim 2, characterized in that: The polyethylene polyamine is at least one of diethylenetriamine and triethylenetetramine.

4. The method for preparing the high-sulfur and high-acid crude oil demulsifier according to claim 1, characterized in that: The preparation method of the zwitterionic surfactant comprises the following steps: The oleic acid, monomer A, solvent and antioxidant are mixed evenly, and the temperature is raised to 100-120°C under an inert atmosphere, and p-toluenesulfonic acid is added, and the reaction is carried out for 2-4 hours to obtain an intermediate; the temperature is lowered to 70-90°C, and a mixture of polyethylene glycol glycidyl ether and polypropylene glycol glycidyl ether and triethylamine are added, and the mixture is mixed evenly, and the reaction is carried out for 3-5 hours; the temperature is lowered to 60-80°C, and leaf alcohol and azobisisobutyronitrile are added and mixed evenly, and the reaction is carried out for 2-3.5 hours; butyl maleate is then added and mixed evenly, and the reaction is carried out for 2.5-4 hours; the temperature is lowered, washed, dried, and distilled to obtain a zwitterionic surfactant with a comb-shaped structure; The monomer A is at least one of 2,6-diaminopyridine and 1-(3-aminopropyl)imidazole; The molar ratio of oleic acid to monomer A is 1:(1-1.2).

5. The method for preparing the high-sulfur and high-acid crude oil demulsifier according to claim 4, characterized in that: The total amount of the polyethylene glycol glycidyl ether and the polypropylene glycol glycidyl ether is 60% to 80% of the mass of the oleic acid.

6. The method for preparing the high-sulfur and high-acid crude oil demulsifier according to claim 1, characterized in that: Before use, the activated alumina undergoes the following pretreatment steps: Mix ethyl orthosilicate, ethanol and water evenly, adjust the pH to 2-3, heat to 35-55°C, react for 3-8 hours, then cool to obtain silica sol, add activated alumina and mix evenly, let stand for 16-24 hours, separate the solid and liquid, place at room temperature, age, dry and calcine to obtain.

7. The method for preparing the high-sulfur and high-acid crude oil demulsifier according to claim 1, characterized in that: When adding activated alumina, 2 to 5 parts by mass of molecular sieves are also added.

8. The method for preparing the high-sulfur and high-acid crude oil demulsifier according to claim 7, characterized in that: Before use, the molecular sieve undergoes the following pretreatment steps: (1) Add the molecular sieve to the copper nitrate solution, mix evenly, heat to 40-60°C, mix for 18-24 hours, separate the solid and liquid, wash, and dry to obtain a preliminarily treated molecular sieve; (2) Mix ethyl orthosilicate, ethanol and water evenly, adjust the pH to 2-3, heat to 35-55°C, react for 3-8 hours, cool to obtain silica sol, add the pre-treated molecular sieve, mix evenly at room temperature, let stand for 16-24 hours, separate the solid and liquid, leave at room temperature, dry, and calcine to obtain the pre-coated molecular sieve; (3) Add the preliminarily coated molecular sieve to the polyethylene glycol solution, mix evenly, raise the temperature to 45-65°C, mix for 6-8 hours, separate the solid and liquid, wash, and dry to obtain.

9. The method for preparing a high-sulfur and high-acid crude oil demulsifier according to claim 1, characterized in that: The corrosion inhibitor is oleic acid imidazoline.

10. The method for preparing a high-sulfur and high-acid crude oil demulsifier according to claim 1, characterized in that: The demulsifier is compounded with polyacrylamide, and the amount of the polyacrylamide used is 2% to 4% of the mass of the demulsifier.

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