Demulsifier for eliminating oil-water interface emulsion layer in oilfield produced liquid treatment and preparation method thereof

Abstract

The invention belongs to the technical field of sewage treatment, and particularly relates to a demulsifier for eliminating an oil-water interface emulsion layer in oilfield produced liquid treatment and a preparation method of the demulsifier. The preparation method comprises the following steps: adding acrylamide, 1-allyl-3-methylimidazolium bis (trifluoromethanesulfonyl) imine salt, allyl tributyl phosphonium chloride and deionized water into a first reactor, and heating and dissolving the acrylamide, the 1-allyl-3-methylimidazolium bis (trifluoromethanesulfonyl) imine salt, the allyl tributyl phosphonium chloride and the deionized water; adding allyl (diisopropylamino) dimethylsilane, butyl acrylate, deionized water, octylphenol polyoxyethylene ether-10, lauryl sodium sulfate and monopotassium phosphate into the second reactor, and stirring to obtain an emulsion; adding an initiator and sodium hydrogen sulfite into a second reactor, carrying out heating and heat preservation reaction, pouring the mixed solution in the first reactor, and continuously carrying out reaction, heating and heat preservation to obtain a viscous liquid; and drying and granulating the viscous liquid to obtain the demulsifier. The demulsifier provided by the invention has the characteristics of simple synthesis process and high demulsification rate.

Description

Technical Field

[0001] The invention belongs to the technical field of sewage treatment, and in particular relates to a demulsifier for eliminating an emulsified layer at an oil-water interface for treating oilfield produced fluid and a preparation method thereof. Background Art

[0002] With the continuous advancement of oilfield mining technology and the extension of oilfield mining life, more and more oil wells have entered a high water content period, and the water content in oilfield produced fluid has increased significantly. The water content of some oilfield produced fluids even exceeds 90%. Oilfield produced fluids contain a large amount of suspended impurities, dissolved impurities (such as various gases and salts) and emulsified oil, which makes the treatment of oilfield produced fluids particularly complicated and difficult. In the treatment process, oil-water emulsification is a common problem. Because the produced fluid contains various surfactants, colloids, asphaltene and other components, these components will form a stable oil-water emulsion layer under certain conditions, making it difficult to effectively separate oil and water.

[0003] If emulsions are not properly handled, they can cause many serious problems. In crude oil processing, water and impurities can affect refining efficiency and product quality, leading to equipment corrosion, catalyst poisoning, etc.; in transportation, they can increase pipeline loads, increase transportation costs, and may cause pipeline blockages; in storage, they can reduce crude oil storage stability and shorten storage cycles. Therefore, efficient separation of oil-water emulsions has become a key issue that needs to be urgently addressed in the petroleum industry.

[0004] In order to solve the problem of oil-water emulsification, scientists have developed a variety of demulsifiers. Demulsifiers are chemicals that can destroy the emulsion layer at the oil-water interface and separate the oil-water mixture into two incompatible phases (oil phase and water phase). Demulsifiers achieve oil-water separation by changing the properties of the oil-water interface, reducing interfacial tension, and destroying the stability of the emulsion layer.

[0005] CN106565007A discloses a deoiling agent for produced water of ternary composite flooding, wherein the deoiling agent is prepared by reacting 2,5-pyridinediamine with formaldehyde and formic acid to generate an intermediate, and then reacting with sodium chlorododecanoate to generate a zwitterionic deoiling agent, wherein the molar ratio of the 2,5-pyridinediamine, formaldehyde, formic acid and sodium chlorododecanoate is 1:2.5-6:2.5-5.5:0.8-2.5, preferably 1:3:3:1.5. Although the invention has a relatively simple preparation process, strong adaptability, low cost, strong salt resistance and good deoiling effect, the agent uses pyridine in the preparation process, and the pyridine monomer is highly toxic, which will inevitably cause harm to the human body and the environment.

[0006] CN101113028A discloses a demulsifying purifier, characterized in that it is composed of the following raw materials in weight percentage: 2% to 68% of sewage, 2% to 37% of polyferric sulfate, 5% to 45% of polyaluminium chloride, 6% to 57% of anhydrous calcium chloride, and 19% to 47% of ferric chloride; its preparation method is: pouring sewage, polyferric sulfate and polyaluminium chloride into a blender, then pouring anhydrous calcium chloride and adding 50% of the total water of the four raw materials, stirring fully, stirring at a speed of 60 revolutions per minute, ensuring that the solid components are completely dissolved, and keeping time for 2-3 hours; then adding ferric chloride and continuing stirring, stirring at a speed of 50-80 revolutions per minute, the time is half to 1 hour, and after stopping for 6-10 hours, filtering and packing into the product packaging barrel. The use concentration of the agent during demulsification of the invention is 300-500mg / L, the dosage is large, the operation is cumbersome, and a large amount of scum will be generated, and a large amount of the agent will be left in the water body, causing secondary pollution. Summary of the invention

[0007] The present invention aims at the deficiencies of the existing technology and provides a demulsifier for eliminating the oil-water interface emulsion layer for treating oilfield produced fluid and a preparation method thereof. The demulsifier of the present invention has the characteristics of simple synthesis process and high demulsification rate.

[0008] One of the purposes of the present invention is to disclose a demulsifier for eliminating the emulsion layer at the oil-water interface for treating oilfield produced fluid. The molecular formula of the demulsifier is as follows: in: a=20000-200000; b = 2000-40000; c = 4000-80000; d = 2000-40000; e=4000-80000.

[0009] Preferably, the viscosity average molecular weight of the demulsifier is 5,000,000-10,000,000.

[0010] Another object of the present invention is to disclose a method for preparing a demulsifier for eliminating the emulsion layer at the oil-water interface for treating oilfield produced fluid. The specific steps of the preparation method are as follows: (1) Add acrylamide, 1-allyl-3-methylimidazolium bis(trifluoromethanesulfonyl)imide salt, allyl tributylphosphine chloride and deionized water into the first reactor, heat to dissolve, and adjust the pH to 7-8 with sodium hydroxide solution; (2) Purge the second reactor and pipeline with nitrogen for 8-12 minutes, add allyl (diisopropylamino) dimethyl silane, butyl acrylate, deionized water, octylphenol polyoxyethylene ether-10, sodium dodecyl sulfate, and potassium dihydrogen phosphate, stir to form an emulsion, and adjust the pH to 7-8 with sodium hydroxide solution; (3) Add initiator and sodium bisulfite to the second reactor, raise the temperature to 50-60°C, and keep the temperature to react. When the viscosity starts to rise, pour the mixed solution in the first reactor into the reactor, continue the reaction for 0.5-4h, raise the temperature to 70-80°C, keep the temperature for 1-2h, and adjust the pH to 7-8 with sodium hydroxide solution to obtain a viscous liquid; (4) The viscous liquid is dried and granulated to obtain a demulsifier.

[0011] In the present invention, preferably, based on 1 mol part of acrylamide, the amounts of 1-allyl-3-methylimidazolium bis(trifluoromethanesulfonyl)imide salt, allyl tributylphosphine chloride, allyl (diisopropylamino) dimethylsilane, and butyl acrylate are 0.1-0.2, 0.2-0.4, 0.1-0.2, and 0.2-0.4 mol parts, respectively.

[0012] In the present invention, preferably, in step (1), the mass ratio of deionized water to acrylamide is 6-8:1.

[0013] In the present invention, preferably, in step (2), the mass ratio of deionized water, octylphenol polyoxyethylene ether-10, sodium lauryl sulfate, potassium dihydrogen phosphate and acrylamide is 3-4: 0.05-0.1: 0.02-0.05: 0.05-0.1: 1.

[0014] In the present invention, preferably, in step (3), the initiator is one of sodium persulfate, potassium persulfate and ammonium persulfate, and the mass ratio of the initiator, sodium bisulfite and acrylamide is 0.05-0.1:0.02-0.05:1.

[0015] The synthetic reaction equation of the demulsifier of the present invention is as follows: The demulsifier of the present invention is a polymer demulsifier with polyethylene as the main chain and various long-chain functional groups as side chains. The polyacrylamide as the main body can absorb suspended particles and colloidal substances in water to form larger flocs, which can capture and sweep emulsion droplets during the sedimentation process, thereby accelerating oil-water separation; the polyester molecules are adsorbed on the oil-water interface, destroying the stability of the interface film to achieve flocculation and demulsification; the cationic quaternary phosphonium salt and the imidazole salt neutralize the charge with the negatively charged emulsion droplets, compress and destroy the double electric layer, weaken the strength of the interface film, make the emulsion droplets collide and coalesce, make the oil droplets lose the repulsive effect and gather together, make the tiny oil droplets gather and release to form oil droplets with large particle size, thereby achieving the purpose of demulsification; the fluorocarbon and silane molecules form a hydrophobic film at the oil-water interface, destroy the original emulsion film, and promote the coalescence of droplets by reducing the interfacial tension; the polyester molecules are adsorbed on the oil-water interface, destroying the stability of the interface film to achieve the flocculation and demulsification effect.

[0016] Compared with the prior art, the present invention has the following advantages and beneficial effects: The demulsifier of the present invention has a good demulsification effect. For the emulsified oil of 32000 mg / L in the oil-water transition zone of the gathering and transportation, when the concentration is 50 mg / L, the dehydration amount of 100 ml of emulsion reaches 91 ml or more in 90 minutes. The water phase after demulsification is clear, the oil content is not higher than 72 mg / L, and the oil-water interface is clear. DETAILED DESCRIPTION

[0017] The present invention will be further described in detail below in conjunction with specific examples and with reference to data. It should be understood that these examples are only intended to illustrate the present invention and are not intended to limit the scope of the present invention in any way.

[0018] Example 1 (1) Add 0.5 mol acrylamide, 0.05 mol 1-allyl-3-methylimidazolium bis(trifluoromethanesulfonyl)imide salt, 0.2 mol allyl tributylphosphine chloride, and 213 g deionized water into the first reactor, heat to dissolve, and adjust the pH to 7-8 with sodium hydroxide solution; (2) The second reactor and pipeline were purged with nitrogen for 10 min, 0.05 mol of allyl (diisopropylamino) dimethyl silane, 0.2 mol of butyl acrylate, 142 g of deionized water, 3.55 g of octylphenol polyoxyethylene ether-10, 1.78 g of sodium dodecyl sulfate, and 3.55 g of potassium dihydrogen phosphate were added, and stirred to form an emulsion, and the pH was adjusted to 7-8 with sodium hydroxide solution; (3) Add 3.55g sodium persulfate and 1.78g sodium bisulfite to the second reactor, raise the temperature to 50°C, and keep the temperature to react. When the viscosity begins to rise, pour the mixed solution in the first reactor into the reactor, continue the reaction for 0.5h, raise the temperature to 80°C, keep the temperature for 1h, and adjust the pH to 7-8 with sodium hydroxide solution to obtain a viscous liquid. (4) The viscous liquid is dried and granulated to obtain a demulsifier.

[0019] Example 2 (1) Add 0.5 mol acrylamide, 0.06 mol 1-allyl-3-methylimidazolium bis(trifluoromethanesulfonyl)imide salt, 0.19 mol allyl tributylphosphine chloride, and 228 g deionized water into the first reactor, heat to dissolve, and adjust the pH to 7-8 with sodium hydroxide solution; (2) The second reactor and pipeline were purged with nitrogen for 8 min, 0.05 mol of allyl (diisopropylamino) dimethyl silane, 0.18 mol of butyl acrylate, 133 g of deionized water, 3.13 g of octylphenol polyoxyethylene ether-10, 1.58 g of sodium dodecyl sulfate, and 3.05 g of potassium dihydrogen phosphate were added, and stirred to form an emulsion, and the pH was adjusted to 7-8 with sodium hydroxide solution; (3) Add 3.14 g of sodium persulfate and 1.52 g of sodium bisulfite to the second reactor, raise the temperature to 60 °C, and keep the temperature to react. When the viscosity begins to rise, pour the mixed solution in the first reactor into the reactor, continue the reaction for 0.5 h, raise the temperature to 80 °C, keep the temperature for 2 h, and adjust the pH to 7-8 with sodium hydroxide solution to obtain a viscous liquid. (4) The viscous liquid is dried and granulated to obtain a demulsifier.

[0020] Example 3 (1) Add 0.5 mol acrylamide, 0.07 mol 1-allyl-3-methylimidazolium bis(trifluoromethanesulfonyl)imide salt, 0.18 mol allyl tributylphosphine chloride, and 237 g deionized water into the first reactor, heat to dissolve, and adjust the pH to 7-8 with sodium hydroxide solution; (2) The second reactor and pipeline were purged with nitrogen for 10 min, 0.06 mol of allyl (diisopropylamino) dimethyl silane, 0.16 mol of butyl acrylate, 132 g of deionized water, 2.83 g of octylphenol polyoxyethylene ether-10, 1.2 g of sodium dodecyl sulfate, and 2.75 g of potassium dihydrogen phosphate were added, and stirred to form an emulsion, and the pH was adjusted to 7-8 with sodium hydroxide solution; (3) Add 3.05 g of sodium persulfate and 1.33 g of sodium bisulfite to the second reactor, raise the temperature to 50 °C, and keep the temperature to react. When the viscosity begins to rise, pour the mixed solution in the first reactor into the reactor, continue the reaction for 4 h, raise the temperature to 80 °C, keep the temperature for 1.6 h, and adjust the pH to 7-8 with sodium hydroxide solution to obtain a viscous liquid. (4) The viscous liquid is dried and granulated to obtain a demulsifier.

[0021] Example 4 (1) Add 0.5 mol acrylamide, 0.08 mol 1-allyl-3-methylimidazolium bis(trifluoromethanesulfonyl)imide salt, 0.16 mol allyl tributylphosphine chloride, and 243 g deionized water into the first reactor, heat to dissolve, and adjust the pH to 7-8 with sodium hydroxide solution; (2) The second reactor and pipeline were purged with nitrogen for 9 minutes, 0.07 mol of allyl (diisopropylamino) dimethyl silane, 0.15 mol of butyl acrylate, 125 g of deionized water, 2.55 g of octylphenol polyoxyethylene ether-10, 1.08 g of sodium dodecyl sulfate, and 2.43 g of potassium dihydrogen phosphate were added, and stirred to form an emulsion, and the pH was adjusted to 7-8 with sodium hydroxide solution; (3) Add 3.15g potassium persulfate and 1.06g sodium bisulfite to the second reactor, raise the temperature to 55°C, and keep the temperature to react. When the viscosity begins to rise, pour the mixed solution in the first reactor into the reactor, continue the reaction for 2h, raise the temperature to 76°C, keep the temperature for 1h, and adjust the pH to 7-8 with sodium hydroxide solution to obtain a viscous liquid. (4) The viscous liquid is dried and granulated to obtain a demulsifier.

[0022] Example 5 (1) Add 0.5 mol acrylamide, 0.08 mol 1-allyl-3-methylimidazolium bis(trifluoromethanesulfonyl)imide salt, 0.14 mol allyl tributylphosphine chloride, and 263 g deionized water into the first reactor, heat to dissolve, and adjust the pH to 7-8 with sodium hydroxide solution; (2) The second reactor and pipeline were purged with nitrogen for 10 min, 0.08 mol of allyl (diisopropylamino) dimethyl silane, 0.14 mol of butyl acrylate, 122 g of deionized water, 2.15 g of octylphenol polyoxyethylene ether-10, 0.92 g of sodium dodecyl sulfate, and 2.1 g of potassium dihydrogen phosphate were added, and stirred to form an emulsion, and the pH was adjusted to 7-8 with sodium hydroxide solution; (3) Add 3.25g potassium persulfate and 0.78g sodium bisulfite to the second reactor, raise the temperature to 58°C, and keep the temperature to react. When the viscosity begins to rise, pour the mixed solution in the first reactor into the reactor, continue the reaction for 1h, raise the temperature to 70°C, keep the temperature for 1.2h, and adjust the pH to 7-8 with sodium hydroxide solution to obtain a viscous liquid. (4) The viscous liquid is dried and granulated to obtain a demulsifier.

[0023] Example 6 (1) Add 0.5 mol acrylamide, 0.09 mol 1-allyl-3-methylimidazolium bis(trifluoromethanesulfonyl)imide salt, 0.12 mol allyl tributylphosphine chloride, and 278 g deionized water into the first reactor, heat to dissolve, and adjust the pH to 7-8 with sodium hydroxide solution; (2) The second reactor and pipeline were purged with nitrogen for 11 minutes, 0.09 mol of allyl (diisopropylamino) dimethyl silane, 0.12 mol of butyl acrylate, 110 g of deionized water, 1.95 g of octylphenol polyoxyethylene ether-10, 0.78 g of sodium dodecyl sulfate, and 1.98 g of potassium dihydrogen phosphate were added, and stirred to form an emulsion, and the pH was adjusted to 7-8 with sodium hydroxide solution; (3) Add 1.78 g of ammonium persulfate and 0.71 g of sodium bisulfite to the second reactor, raise the temperature to 60 °C, and keep the temperature to react. When the viscosity begins to rise, pour the mixed solution in the first reactor into the reactor, continue the reaction for 1 hour, raise the temperature to 72 °C, keep the temperature for 2 hours, and adjust the pH to 7-8 with sodium hydroxide solution to obtain a viscous liquid; (4) The viscous liquid is dried and granulated to obtain a demulsifier.

[0024] Example 7 (1) Add 0.5 mol acrylamide, 0.1 mol 1-allyl-3-methylimidazolium bis(trifluoromethanesulfonyl)imide salt, 0.1 mol allyl tributylphosphine chloride, and 284 g deionized water into the first reactor, heat to dissolve, and adjust the pH to 7-8 with sodium hydroxide solution; (2) The second reactor and pipeline were purged with nitrogen for 12 minutes, and 0.1 mol of allyl (diisopropylamino) dimethyl silane, 0.1 mol of butyl acrylate, 106.5 g of deionized water, 1.78 g of octylphenol polyoxyethylene ether-10, 0.71 g of sodium dodecyl sulfate, and 1.78 g of potassium dihydrogen phosphate were added and stirred to form an emulsion, and the pH was adjusted to 7-8 with sodium hydroxide solution; (3) Add 2.55g of ammonium persulfate and 1.28g of sodium bisulfite to the second reactor, raise the temperature to 53°C, and keep the temperature to react. When the viscosity begins to rise, pour the mixed solution in the first reactor into the reactor, continue the reaction for 4h, raise the temperature to 70°C, keep the temperature for 1.5h, and adjust the pH to 7-8 with sodium hydroxide solution to obtain a viscous liquid. (4) The viscous liquid is dried and granulated to obtain a demulsifier.

[0025] Example 8 Demulsifier Performance Evaluation The demulsification performance of the demulsifier of the present invention (Examples 1-7) was tested by taking crude oil from the oil-water transition zone in the crude oil storage tank of a certain oil production plant joint station in Shengli Oilfield. The emulsified oil in the oil-water transition zone had an oil content of 32000 mg / L. The evaluation method was based on SY / T 5281-2000 "Crude Oil Demulsifier Performance Test Method", the experimental temperature was 60°C, and the dosing concentration was 30 and 50 mg / L. The SP-169 crude oil demulsifier from Hai'an Petrochemical Plant in Jiangsu Province was used for comparative experiments, and the test results are shown in Table 1.

[0026] Table 1 Experimental results of crude oil demulsifier From Table 1 we can see that: (1) When the demulsifier of the present invention (Examples 1-7) is used at a concentration of 30 mg / L for 32000 mg / L crude oil in the oil-water transition zone of the crude oil storage tank of the oil production plant joint station, the dehydration amount of 100 ml of emulsion in 90 minutes reaches 89 ml or more, the water phase after demulsification is clear, the oil content is not higher than 76 mg / L, and the oil-water interface is clear; while the SP-169 crude oil demulsifier of the comparative example Hai'an Petrochemical Plant in Jiangsu Province has a dehydration amount of 70 ml in 90 minutes, the oil-water interface after demulsification is blurred, the oil content is 250 mg / L, and the demulsification effect is significantly lower than that of the present invention; (2) When the demulsifier of the present invention (Examples 1-7) is used at a concentration of 50 mg / L for 32000 mg / L crude oil in the oil-water transition zone of the crude oil storage tank of the oil production plant joint station, the dehydration amount of 100 ml of emulsion in 90 minutes reaches 91 ml or more, the water phase after demulsification is clear, the oil content is not higher than 72 mg / L, and the oil-water interface is clear; while the SP-169 crude oil demulsifier of the comparative example Hai'an Petrochemical Plant in Jiangsu Province has a dehydration amount of 82 ml in 90 minutes, a clear oil-water interface after demulsification, and an oil content of 102 mg / L, and the demulsification effect is significantly lower than that of the present invention.

[0027] The preferred embodiments of the present invention are described in detail above, but the present invention is not limited thereto. Within the technical concept of the present invention, the technical solution of the present invention can be subjected to a variety of simple modifications, including the combination of various technical features in any other suitable manner, and these simple modifications and combinations should also be regarded as the contents disclosed by the present invention and belong to the protection scope of the present invention.

Claims

1. A method for preparing a demulsifier for eliminating the emulsion layer at the oil-water interface for treating oilfield produced fluid, characterized in that: The specific steps of the preparation method are as follows: (1) Add acrylamide, 1-allyl-3-methylimidazolium bis(trifluoromethanesulfonyl)imide salt, allyl tributylphosphine chloride and deionized water into the first reactor, heat to dissolve, and adjust the pH to 7-8 with sodium hydroxide solution; (2) Purge the second reactor and pipeline with nitrogen for 8-12 minutes, add allyl (diisopropylamino) dimethyl silane, butyl acrylate, deionized water, octylphenol polyoxyethylene ether-10, sodium dodecyl sulfate, and potassium dihydrogen phosphate, stir to form an emulsion, and adjust the pH to 7-8 with sodium hydroxide solution; (3) Add initiator and sodium bisulfite to the second reactor, raise the temperature to 50-60°C, and keep the temperature to react. When the viscosity starts to rise, pour the mixed solution in the first reactor into the reactor, continue the reaction for 0.5-4h, raise the temperature to 70-80°C, keep the temperature for 1-2h, and adjust the pH to 7-8 with sodium hydroxide solution to obtain a viscous liquid; (4) Drying and granulating the viscous liquid to obtain a demulsifier; Based on 1 mol part of acrylamide, the amounts of 1-allyl-3-methylimidazolium bis(trifluoromethanesulfonyl)imide salt, allyl tributylphosphine chloride, allyl (diisopropylamino) dimethylsilane, and butyl acrylate are 0.1-0.2, 0.2-0.4, 0.1-0.2, and 0.2-0.4 mol parts, respectively.

2. The method for preparing a demulsifier for eliminating the emulsion layer at the oil-water interface for treating oilfield produced fluid according to claim 1, characterized in that: In step (1), the mass ratio of deionized water to acrylamide is 6-8:

1.

3. The method for preparing a demulsifier for eliminating the emulsion layer at the oil-water interface for treating oilfield produced fluid according to claim 1, characterized in that: In step (2), the mass ratio of deionized water, octylphenol polyoxyethylene ether-10, sodium lauryl sulfate, potassium dihydrogen phosphate and acrylamide is 3-4: 0.05-0.1：0.02-0.05：0.05-0.1：1。 4. The method for preparing a demulsifier for eliminating the emulsion layer at the oil-water interface for treating oilfield produced fluid according to claim 1, characterized in that: In step (3), the mass ratio of the initiator, sodium bisulfite and acrylamide is 0.05-0.1:0.02-0.05:

1.

5. The method for preparing a demulsifier for eliminating the emulsion layer at the oil-water interface for treating oilfield produced fluid according to claim 1, characterized in that: The initiator is one of sodium persulfate, potassium persulfate and ammonium persulfate.

6. A demulsifier for eliminating the emulsion layer at the oil-water interface for treating oilfield produced fluid, characterized in that: The molecular formula of the demulsifier is as follows: in: a=20000-200000； b=2000-40000； c=4000-80000； d=2000-40000； e=4000-80000。 7. The demulsifier according to claim 6, characterized in that The viscosity average molecular weight of the demulsifier is 5,000,000-10,000,000.

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