Demulsifier for oil mining and preparation method thereof

Abstract

The present invention relates to a demulsifier for oil production and a preparation method thereof, and belongs to the technical field of demulsifiers for oil production. A preparation method for a demulsifier for oil production comprises the following steps: slowly adding silicon dioxide to a mixed acid, controlling the temperature and stirring, removing impurities, and drying to obtain a pretreated product; stirring and mixing a silane coupling agent and ethyl acetate, adding sorbitol and reacting at a constant temperature, cooling to room temperature, centrifuging, placing in anhydrous ethanol, adding the pretreated product and ultrasonically dispersing, heating and stirring, removing impurities, vacuum drying, placing in deionized water and mixing, stirring at high speed, adding acrylamide and benzyl methacrylate and stirring and mixing, adding an initiator and heating and stirring, continuing to heat and stir, cooling, adjusting the pH value, and placing in a granulator for granulation to obtain the demulsifier. The demulsifier of the present invention performs well in treating oilfield produced fluid. It can quickly exert its efficacy, and as the dosage increases, the treatment effect is further improved, thereby making the aqueous phase clearer.

Description

Technical Field

[0001] The invention belongs to the technical field of demulsifiers for petroleum, and relates to a demulsifier for petroleum mining and a preparation method thereof. Background Art

[0002] A large amount of produced fluid from oilfields exists as an oil-in-water (O / W) emulsion. Reverse demulsifiers play a crucial role in the treatment of produced fluids from oilfields. In actual produced fluid treatment processes, reverse demulsifiers are added to three-phase separators to promote efficient separation of O / W emulsions. They achieve this by altering the interfacial properties between the oil droplets and the aqueous phase, reducing interfacial tension and encouraging the oil droplets to collide and coalesce, thereby achieving oil-water separation.

[0003] The existing patent publication number is: CN104560130A discloses a method for preparing a petroleum demulsifier. Acrylic acid, propylene glycol and dimethyl adipate are added to a reactor, potassium hydroxide and trimethylolpropane are added, the air in the reactor is replaced with an inert gas, the temperature is raised and stirred, and then vacuum is evacuated. The temperature is raised again and epichlorohydrin and diphenylmethane diisocyanate are added, and the stirring reaction is continued to obtain reactant 1; potassium hydroxide, propylene glycol polyether, 1,3-butadiene and reactant 1 are then added to the reactor, the temperature is raised and stirred under the protection of an inert gas, and the temperature is raised again and continued to stir and react until the temperature is cooled to room temperature to obtain reactant 2; polyethylene glycol, polyvinyl formal, methanol and deionized water are then added to the reactor, heated under vacuum conditions for reaction, and then cooled to room temperature to obtain reactant 3; finally, reactant 2 and reactant 3 are mixed, and heated and stirred to obtain a demulsifier. The demulsifier obtained by the method of the invention can exert a good demulsification effect over a wide temperature range. However, traditional demulsifiers (such as polyoxyethylene-polyoxypropylene block copolymers and quaternary ammonium salts) face problems such as low demulsification efficiency, insufficient temperature and salt resistance, and narrow scope of application. Summary of the Invention

[0004] The present invention provides a demulsifier for use in oil production and a method for preparing the same. The demulsifier of the present invention excels in treating oilfield produced fluids. It exhibits rapid efficacy, and as the dosage increases, the treatment effect is further enhanced, resulting in a clearer aqueous phase. The demulsifier is not only economical to use and exhibits significant treatment effects, but also has a simple production process, facilitating large-scale production. Therefore, it has great potential for application and broad market prospects in the field of oilfield produced fluid treatment.

[0005] The purpose of the present invention can be achieved through the following technical solutions:

[0006] A method for preparing a demulsifier for oil production comprises the following steps:

[0007] Step 1: adding silica to the mixed acid, controlling the temperature and stirring, centrifuging, washing, and drying to obtain a pretreated product;

[0008] Step 2: Stir and mix the silane coupling agent and ethyl acetate, add sorbitaldehyde to react, cool, centrifuge, place in anhydrous ethanol, add the pretreated product to ultrasonically disperse, heat and stir, filter, wash, and dry to obtain an intermediate product;

[0009] Step 3: Mix the intermediate product and water, stir at high speed, add acrylamide and benzyl methacrylate and stir, add initiator and heat and stir, continue heating and stirring, cool, adjust pH, place in a granulator and granulate to obtain.

[0010] As a preferred technical solution of the present invention, the above preparation method comprises the following steps:

[0011] Step 1: Slowly add silica to the mixed acid while controlling the temperature and stirring, centrifuge and wash until neutral, and dry to obtain a pretreated product;

[0012] Step 2: Stirring and mixing a silane coupling agent and ethyl acetate, adding sorbaldehyde to react at a constant temperature, cooling to room temperature, centrifuging, placing in anhydrous ethanol, adding the pretreated product to ultrasonically disperse, heating and stirring, filtering, washing with alcohol, and vacuum drying to obtain an intermediate product; utilizing the amino group of the silane coupling agent to react with the aldehyde group of sorbaldehyde, and then the siloxane bond of the silane coupling agent reacts with the hydroxyl group on the surface of silica to obtain an intermediate product; the reaction formula is:

[0013] .

[0014] Step 3: Under an inert atmosphere, mix the intermediate product with deionized water and stir at high speed. Add acrylamide and benzyl methacrylate and stir to mix thoroughly. Add an initiator and heat with stirring. Continue heating and stirring. Cool the temperature, adjust the pH, and granulate in a granulator to obtain the product. Under the action of the initiator, the alkenyl groups of sorbital in the intermediate product serve as polymerization sites, reacting with acrylamide and benzyl methacrylate to form an alkenyl polymerization reaction.

[0015] As a preferred technical solution of the present invention, in step 1, the mixed acid is composed of concentrated sulfuric acid and concentrated nitric acid in a volume ratio of 1:0.5-1.5, and the temperature-controlled stirring is stirring at 30-50°C for 2-3 hours.

[0016] As a preferred technical solution of the present invention, in step 1, the drying is performed at 110° C. for 1.5-2.0 h, and the amount ratio of the silicon dioxide to the mixed acid is 1.0-1.2 g: 25-30 mL.

[0017] As a preferred technical solution of the present invention, in step 2, the silane coupling agent is N-β-(aminoethyl)-γ-aminopropylmethyldimethoxysilane.

[0018] As a preferred technical solution of the present invention, in step 2, the constant temperature reaction is a reaction at 50-62°C for 4-6 hours, the ultrasonic dispersion is an ultrasonic power of 200-300W for 30-45 minutes, the heating and stirring is stirring at a temperature of 50-60°C for 4-6 hours, and the washing with alcohol is washing with pure ethanol for 3 times.

[0019] As a preferred technical solution of the present invention, in step 2, the mass ratio of the silane coupling agent, ethyl acetate, sorbitaldehyde, anhydrous ethanol and the pretreatment product is 10-13:40-50:18-25:60-80:12-14.

[0020] As a preferred technical solution of the present invention, in step three, the high-speed stirring is stirring at 1000-1200 rpm for 5-8 minutes, the heating stirring is stirring at 50-60°C for 1.0-1.5 hours, the continued heating stirring is stirring at 80-90°C for 0.5-1.0 hours, the cooling is cooling to 40-50°C, the pH value is adjusted to 7, and the particle size after granulation is 1-2 mm.

[0021] As a preferred technical solution of the present invention, in step three, the mass ratio of the intermediate product, deionized water, acrylamide, benzyl methacrylate and initiator is 3.0-3.5:40-50:14-16:21-26:2.4-3.0.

[0022] As a preferred technical solution of the present invention, in step three, the initiator is composed of an oxidizing persulfate and a reducing sulfur-containing salt; the mass ratio of the oxidizing persulfate to the reducing sulfur-containing salt is 2:1; the oxidizing persulfate is one or more of ammonium persulfate, potassium persulfate and sodium persulfate; and the reducing sulfur-containing salt is one or more of sodium bisulfite, sodium sulfite and sodium thiosulfate.

[0023] The invention discloses a demulsifier for petroleum mining prepared by adopting the preparation method.

[0024] Beneficial effects of the present invention:

[0025] The demulsifier of the present invention performs exceptionally well in treating oilfield produced fluids. It rapidly exerts its efficacy, and as the dosage increases, the treatment effect is further enhanced, resulting in a clearer aqueous phase. This demulsifier is not only economical to use and exhibits significant treatment effects, but also has a simple production process, facilitating large-scale production. Therefore, it has great potential for application and broad market prospects in the field of oilfield produced fluid treatment.

[0026] The invention adopts the following methods in the preparation of a demulsifier for petroleum mining: silicon dioxide is subjected to mixed acidification treatment to increase the degree of surface hydroxylation, thereby affecting the grafting of silane; diamino groups and sorbitaldehyde of a silane coupling agent are introduced into hydrophobic segments to adjust the hydrophilic-lipophilic balance and simultaneously bridge with the silicon dioxide; acrylamide increases hydrophilicity and adsorption capacity, and benzyl methacrylate enhances hydrophobicity. All components jointly influence the efficiency of the demulsifier in destroying the stability of the oil-water emulsion by regulating the balance of hydrophilic and hydrophobic groups in the molecular structure, the interface adsorption capacity and the molecular chain bridging effect. BRIEF DESCRIPTION OF THE DRAWINGS

[0027] Figure 1 It is the infrared spectrum of the intermediate product of Example 1.

[0028] Figure 2 It is the infrared spectrum of the demulsifier of Example 1. DETAILED DESCRIPTION

[0029] In order to further illustrate the technical means and effects adopted by the present invention to achieve the predetermined purpose of the invention, the specific implementation methods, structures, features and effects of the present invention are described in detail below in combination with the embodiments.

[0030] Example 1

[0031] A method for preparing a demulsifier for oil production comprises the following steps:

[0032] Step 1: Slowly add silica to the mixed acid and stir at 30°C for 2 hours. Centrifuge to obtain the solid, wash with deionized water until the surface is neutral, and dry at 110°C for 1.5 hours to obtain a pretreated product.

[0033] In step 1, the mixed acid is composed of concentrated sulfuric acid and concentrated nitric acid in a volume ratio of 1:1, and the amount ratio of the silicon dioxide to the mixed acid is 1.0 g: 25 mL;

[0034] Step 2: Stir and mix the silane coupling agent and ethyl acetate, add sorbitaldehyde and react at 50°C for 4 hours, cool to room temperature, centrifuge, place in anhydrous ethanol, add the pretreated product and ultrasonicate at 200W power for 30 minutes, stir at 50°C for 4 hours, filter, wash with pure ethanol 3 times, and vacuum dry at 80°C to constant weight to obtain an intermediate product; Figure 1 The absorption peak of Si-O-Si in silica is at 1088 cm -1 Position, 1647cm -1 The absorption peak of C=N bond is generated by the Schiff base reaction between the amino group of N-β-(aminoethyl)-γ-aminopropylmethyldimethoxysilane and the aldehyde group of sorbitaldehyde, and the C=N bond is generated. 1565cm -1 It is the characteristic peak of the alkenyl -C=C- in sorbital.

[0035] In step 2, the silane coupling agent is N-β-(aminoethyl)-γ-aminopropylmethyldimethoxysilane, and the mass ratio of the silane coupling agent, ethyl acetate, sorbitaldehyde, anhydrous ethanol and the pretreated product is 10:40:18:60:12;

[0036] Step 3: Under an inert atmosphere, the intermediate product and deionized water were mixed, and then stirred at 1000 rpm for 5 minutes, acrylamide and benzyl methacrylate were added and stirred for 20 minutes, an initiator was added and stirred at 50°C for 1.0 hour, and stirred at 80°C and 300 rpm for 0.5 hour. The mixture was cooled to 40°C, the pH value was adjusted to 7, and the mixture was granulated in a granulator, and then sieved to obtain a demulsifier with an average particle size of 1 mm; Figure 2 The absorption peak of Si-O-Si in silica is at 1061 cm -1 Position, 1646cm -1 It is the absorption peak of C=N bond, 1551cm -1 The alkenyl peak of sorbitol at 1417-1478 cm is significantly weakened because the alkenyl group undergoes polymerization reaction with acrylamide and benzyl methacrylate. -1 It is the characteristic peak of the benzene ring of benzyl methacrylate, 1718 cm -1 It is the absorption peak of -C=O- bond in benzyl methacrylate; 1752cm -1 The absorption peak of the carbonyl group -C=O- in the amide bond of acrylamide.

[0037] In step three, the mass ratio of the intermediate product, deionized water, acrylamide, benzyl methacrylate and initiator is 3.0:40:14:21:2.4, and the initiator is composed of ammonium persulfate and sodium bisulfite in a mass ratio of 2:1.

[0038] Example 2

[0039] A method for preparing a demulsifier for oil production comprises the following steps:

[0040] Step 1: Slowly add silica to the mixed acid and stir at 40°C for 2.5 hours. Centrifuge to obtain the solid, wash with deionized water until the surface is neutral, and dry at 110°C for 1.8 hours to obtain a pretreated product.

[0041] In step 1, the mixed acid is composed of concentrated sulfuric acid and concentrated nitric acid in a volume ratio of 1:1.2, and the amount ratio of the silicon dioxide to the mixed acid is 1.1 g:28 mL;

[0042] Step 2: Stir and mix the silane coupling agent and ethyl acetate, add sorbitaldehyde and react at 56°C for 5 hours, cool to room temperature, centrifuge, place in anhydrous ethanol, add the pretreated product and ultrasonicate at 250W power for 38 minutes, stir at 55°C for 5 hours, filter, wash with pure ethanol 3 times, and vacuum dry at 80°C to constant weight to obtain an intermediate product;

[0043] In step 2, the silane coupling agent is N-β-(aminoethyl)-γ-aminopropylmethyldimethoxysilane, and the mass ratio of the silane coupling agent, ethyl acetate, sorbitaldehyde, anhydrous ethanol and the pretreated product is 12:45:22:70:13;

[0044] Step 3: Under an inert atmosphere, the intermediate product and deionized water were mixed, and then stirred at 1100 rpm for 6 minutes, acrylamide and benzyl methacrylate were added and stirred for 20 minutes, an initiator was added and stirred at 55°C for 1.2 hours, and stirred at 85°C and 300 rpm for 0.8 hours. The mixture was cooled to 45°C, the pH value was adjusted to 7, and the mixture was granulated in a granulator, and then sieved to obtain a demulsifier with an average particle size of 1.5 mm.

[0045] In step three, the mass ratio of the intermediate product, deionized water, acrylamide, benzyl methacrylate and initiator is 3.2:45:15:24:2.7, and the initiator is composed of ammonium persulfate and sodium bisulfite in a mass ratio of 2:1.

[0046] Example 3

[0047] A method for preparing a demulsifier for oil production comprises the following steps:

[0048] Step 1: Slowly add silica to the mixed acid and stir at 50°C for 3 hours. Centrifuge to obtain the solid, wash with deionized water until the surface is neutral, and dry at 110°C for 2.0 hours to obtain a pretreated product.

[0049] In step 1, the mixed acid is composed of concentrated sulfuric acid and concentrated nitric acid in a volume ratio of 1:1.5, and the amount ratio of the silicon dioxide to the mixed acid is 1.2g:30mL;

[0050] Step 2: Stir and mix the silane coupling agent and ethyl acetate, add sorbitaldehyde, react at 62°C for 6 hours, cool to room temperature, centrifuge, place in anhydrous ethanol, add the pretreated product, ultrasonicate at 300W power for 45 minutes, stir at 60°C for 6 hours, filter, wash with pure ethanol 3 times, and vacuum dry at 80°C to constant weight to obtain an intermediate product;

[0051] In step 2, the silane coupling agent is N-β-(aminoethyl)-γ-aminopropylmethyldimethoxysilane, and the mass ratio of the silane coupling agent, ethyl acetate, sorbitaldehyde, anhydrous ethanol and the pretreated product is 13:50:25:80:14;

[0052] Step 3: Under an inert atmosphere, the intermediate product and deionized water were mixed, and then stirred at 1200 rpm for 8 minutes, acrylamide and benzyl methacrylate were added and stirred for 20 minutes, an initiator was added and stirred at 60°C for 1.5 hours, and stirred at 90°C and 300 rpm for 1.0 hour. The mixture was cooled to 50°C, the pH value was adjusted to 7, and the mixture was granulated in a granulator, and then sieved to obtain a demulsifier with an average particle size of 2 mm;

[0053] In step three, the mass ratio of the intermediate product, deionized water, acrylamide, benzyl methacrylate and initiator is 3.5:50:16:26:3.0, and the initiator is composed of ammonium persulfate and sodium bisulfite in a mass ratio of 2:1.

[0054] Comparative Example 1

[0055] Compared with Example 3, the difference in Comparative Example 1 is that step 1 is not performed, and silicon dioxide replaces the pre-treated product of step 2, and the rest are the same.

[0056] Comparative Example 2

[0057] Compared with Example 3, the difference in Comparative Example 2 is that 2-hexenal replaces sorbitaldehyde, and the rest are the same.

[0058] Comparative Example 3

[0059] Compared with Example 3, Comparative Example 3 is different in that sorbitaldehyde is not used, and the rest are the same.

[0060] Comparative Example 4

[0061] Compared with Example 3, Comparative Example 4 is different in that γ-aminopropyltriethoxysilane is used instead of N-β-(aminoethyl)-γ-aminopropylmethyldimethoxysilane, and the rest are the same.

[0062] Comparative Example 5

[0063] Compared with Example 3, Comparative Example 5 is different in that acrylamide is used instead of benzyl methacrylate, and the rest are the same.

[0064] The demulsifiers prepared in Examples 1-3 and Comparative Examples 1-5 were subjected to the following tests, respectively. The test results are shown in Table 1.

[0065] Determination of oil content in water phase: According to SY / T 5797-1993, the oil content in water phase is 1485 mg / L, the demulsifier dosage is 50 mg / L and 100 mg / L, the temperature is 70°C, and the test time is 10 min.

[0066] Table 1 Test results

[0067]

[0068] From the test results in Table 1, it can be seen that, compared with Comparative Examples 1-5, Examples 1-3 etch the surface of silica by oxidation and acidification, increase the surface active sites, the mixed acid provides a strong acidic environment, and has oxidizing properties, the synergistic effect of concentrated sulfuric acid and concentrated nitric acid can adjust the chemical properties of the silica surface, which is beneficial to the later silane grafting modification, forming a stable Si-O-Si bond, and ensuring the structural integrity of the intermediate product. If the acidification is insufficient, the amount of coupling agent grafted is small, the molecular weight and cross-linking degree of the demulsifier are reduced, and the stability and demulsification effect of the demulsifier are affected. After the amino group of the silane coupling agent reacts with sorbitaldehyde, it can be introduced. The hydrophobic carbon chain segment is then grafted with silica to enhance the inorganic-organic hybrid structure of the demulsifier. If the number of amino groups is insufficient, the cross-linking degree of the intermediate product will be reduced, the flexibility of the molecular chain will be poor, and the adsorption capacity of the demulsifier at the oil-water interface will be affected. The grafted sorbital structure can serve as a flexible segment of the intermediate product and copolymerize with acrylamide and benzyl methacrylate in the polymerization reaction of step three, affecting the molecular weight and segment distribution of the polymer. Benzyl methacrylate is a hydrophobic monomer, and its benzyl structure can enhance the affinity of the demulsifier for the oil phase, promote the penetration of the demulsifier into the oil-water interface membrane, and destroy the stability of the membrane.

[0069] The above description is merely a preferred embodiment of the present invention and does not constitute any form of limitation to the present invention. Although the present invention has been disclosed as a preferred embodiment as above, it is not intended to limit the present invention. Any person skilled in the art can make some changes or modifications to equivalent embodiments using the technical contents disclosed above without departing from the scope of the technical solution of the present invention. However, any indirect modifications, equivalent changes and modifications made to the above embodiments based on the technical essence of the present invention without departing from the content of the technical solution of the present invention still fall within the scope of the technical solution of the present invention.

Claims

1. A method for preparing a demulsifier for oil production, characterized in that: The preparation method comprises the following steps: Step 1: Add silica to the mixed acid, stir at 30-50° C. for 2-3 hours, centrifuge, wash, and dry to obtain a pretreated product; the amount ratio of silica to mixed acid is 1.0-1.2 g: 25-30 mL; the mixed acid is composed of concentrated sulfuric acid and concentrated nitric acid in a volume ratio of 1:0.5-1.5; Step 2: Stir and mix the silane coupling agent and ethyl acetate, add sorbaldehyde, react at 50-62° C. for 4-6 hours, cool, centrifuge, place in anhydrous ethanol, add the pretreated product, ultrasonicate at 200-300W power for 30-45 minutes, stir at 50-60° C. for 4-6 hours, filter, wash, and dry to obtain an intermediate product; the silane coupling agent is N-β-(aminoethyl)-γ-aminopropylmethyldimethoxysilane; the mass ratio of the silane coupling agent, ethyl acetate, sorbaldehyde, anhydrous ethanol, and the pretreated product is 10-13:40-50:18-25:60-80:12-14; Step 3, mixing the intermediate product with water, stirring at 1000-1200 rpm for 5-8 minutes, adding acrylamide and benzyl methacrylate and stirring, adding an initiator and stirring at 50-60° C. for 1.0-1.5 hours, continuing to heat to 80-90° C. and stirring for 0.5-1.0 hours, cooling to 40-50° C., adjusting the pH, and placing in a granulator for granulation to obtain a particle size of 1-2 mm; the mass ratio of the intermediate product, deionized water, acrylamide, benzyl methacrylate and initiator is 3.0-3.5:40-50:14-16:21-26:2.4-3.0; the initiator is composed of an oxidizing persulfate and a reducing sulfur-containing salt; the oxidizing persulfate is one or more of ammonium persulfate, potassium persulfate and sodium persulfate; the reducing sulfur-containing salt is one or more of sodium bisulfite, sodium sulfite and sodium thiosulfate.

2. A demulsifier for petroleum mining prepared by the preparation method according to claim 1.

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