A demulsifier and a method for preparing the same

Abstract

This application discloses a demulsifier and its preparation method, belonging to the field of demulsifier technology. The preparation method of the demulsifier includes: adding ferric chloride hexahydrate, sodium acetate, and polyethylene glycol to a polyol solvent, mixing them evenly at 60-80℃, then adding bentonite and ultrasonically dispersing for 20-40 min, reacting at 180-250℃ for 20-30 h, washing, and drying; ultrasonically dispersing the obtained magnetic bentonite in an organic solvent for 15-30 min, adding a silane coupling agent, stirring at 70-85℃ for 6-10 h, collecting with a magnet, washing, and drying; ultrasonically dispersing the obtained silanized magnetic bentonite in an organic solvent for 15-30 min, dissolving an acrylate copolymer demulsifier and a sulfonate demulsifier in the organic solvent, adding 4-dimethylaminopyridine and ultrasonically dispersing for 10-20 min, then adding it to the silanized magnetic bentonite solution, stirring at 85-110℃ for 4-6 h, collecting with a magnet, washing, and drying to obtain the demulsifier. This demulsifier is safe, environmentally friendly, and can be repeatedly and efficiently used to achieve demulsification.

Description

Technical Field

[0001] This application relates to a demulsifier and its preparation method, belonging to the field of demulsifier technology. Background Technology

[0002] As oilfield development progresses into its later stages, the complexity of oil extraction technology increases significantly. In particular, the widespread use of oil recovery additives leads to a more complex composition of the produced fluid, typically a water-oil emulsion. This emulsion often contains over 80% water, sometimes even exceeding 90%. Such high-water-content crude oil emulsions are extremely detrimental to storage and transportation, not only increasing energy consumption during transport but also potentially causing corrosion and scaling in metal pipelines.

[0003] Effectively separating oil and water from emulsions has become a crucial issue, making the development of efficient demulsification technologies urgent. Currently, chemical demulsification is often achieved on-site, with polyether demulsifiers being the most commonly used. For example, Chinese invention patent application CN121181874A discloses a low-temperature polyether demulsifier for oil and gas gathering and transportation, along with its preparation method. This demulsifier uses cashew nut shell powder, pentaethylene hexamine, and bisphenol F in a specific molar ratio as an initiator, prepared by formaldehyde condensation; it then incorporates propylene oxide and ethylene oxide through staged block copolymerization to form a polyether backbone; it introduces fluorinated epoxy monomers for end-fluorination modification; and finally, it undergoes chain extension and crosslinking with adipic acid and epichlorohydrin. This demulsifier achieves efficient demulsification at low temperatures. However, both ethylene oxide and propylene oxide in this demulsifier are hazardous materials, posing serious safety risks during transportation. Furthermore, this demulsifier may remain in crude oil, negatively impacting downstream processing and environmental protection. Therefore, developing safe, efficient, and environmentally friendly demulsifiers has become an important research direction in the field of oilfield chemistry. Summary of the Invention

[0004] To address the aforementioned issues, a demulsifier and its preparation method are provided, which are safe, environmentally friendly, and can achieve demulsification repeatedly and efficiently.

[0005] According to one aspect of this application, a method for preparing a demulsifier is provided, comprising the following steps:

[0006] (1) Add ferric chloride hexahydrate, sodium acetate and polyethylene glycol to a polyol solvent, mix them evenly at 60-80℃, then add bentonite and ultrasonically disperse for 20-40 min, then react at 180-250℃ for 20-30 h, wash and dry to obtain magnetic bentonite.

[0007] (2) Disperse the magnetic bentonite in an organic solvent by ultrasonication for 15-30 min, add silane coupling agent, stir at 70-85℃ for 6-10 h, then collect with a magnet, wash, and dry to obtain silanized magnetic bentonite.

[0008] (3) Disperse silanized magnetic bentonite in an organic solvent by ultrasonication for 15-30 min to obtain a silanized magnetic bentonite solution. Dissolve acrylate copolymer demulsifier and sulfonate demulsifier in an organic solvent, add 4-dimethylaminopyridine and disperse by ultrasonication for 10-20 min, then add to the silanized magnetic bentonite solution. Stir at 85-110℃ for 4-6 h, separate and collect with a magnet, wash and dry to obtain the demulsifier.

[0009] Optionally, the weight ratio of ferric chloride hexahydrate, sodium acetate, and polyethylene glycol is (1.2-1.7):(3-4):1;

[0010] And / or, the amount of bentonite added is 70-80 wt% of ferric chloride hexahydrate.

[0011] Optionally, the weight ratio of the magnetic bentonite to the silane coupling agent is 1:(3.2-5).

[0012] Optionally, the weight ratio of the silanized magnetic bentonite, the acrylate copolymer demulsifier, and the sulfonate demulsifier is 1:(6-7.2):(2.8-3.5).

[0013] And / or, the amount of 4-dimethylaminopyridine added is 76-83 wt% of silanized magnetic bentonite.

[0014] Optionally, the polyol solvent is ethylene glycol or diethylene glycol;

[0015] And / or, the silane coupling agent is (3-glycidylpropoxy)trimethoxysilane, (3-glycidylpropoxy)triethoxysilane, or (3-glycidylpropoxy)methyldimethoxysilane.

[0016] Optionally, the method for preparing the acrylate copolymer demulsifier includes:

[0017] N-hydroxymethylacrylamide, alkyl acrylate, and 0.8-1.2 wt% of the total weight of the monomers initiator are placed in a reaction vessel, dissolved in an organic solvent, and then an inert gas is introduced. The mixture is heated to 70-80℃ and reacted for 7-15 hours. After the reaction is completed, the system is cooled to room temperature, washed, and dried to obtain the acrylate copolymer demulsifier.

[0018] Optionally, the weight ratio of N-hydroxymethylacrylamide to alkyl acrylate is 1:(1.5-3).

[0019] Optionally, the alkyl acrylate is methyl acrylate, ethyl acrylate, or butyl acrylate;

[0020] And / or, the initiator is azobisisobutyronitrile or benzoyl peroxide;

[0021] And / or, the organic solvent is toluene or xylene.

[0022] Optionally, the sulfonate demulsifier is sodium lauryl hydroxyethyl sulfonate, sodium cocoyl hydroxyethyl sulfonate, or sodium lignin sulfonate.

[0023] According to another aspect of this application, a demulsifier is provided, which is prepared by any of the preparation methods described above.

[0024] The beneficial effects of this application include, but are not limited to:

[0025] 1. The demulsifier and its preparation method of this application involve loading magnetic nanoparticles Fe3O4 onto bentonite, modifying the bentonite with epoxy groups, and then grafting acrylate copolymer demulsifiers and sulfonate demulsifiers to obtain the demulsifier. Bentonite has abundant -OH groups; by surface modification, acrylate copolymer demulsifiers and sulfonate demulsifiers are introduced. The hydrophilic and hydrophobic segments of the acrylate copolymer demulsifier have a suitable ratio, allowing it to disperse well in high-viscosity emulsions, quickly reach the oil-water interface, and thus disrupt the stable interfacial film. Subsequently, adjacent water droplets aggregate until they overcome the resistance of the oil phase and sink, resulting in oil-water separation. The sulfonate demulsifier's sulfonate ions effectively weaken the interactions between asphaltene molecules, reducing the viscoelasticity and density of the interfacial film, thereby promoting the diffusion and adsorption of the acrylate copolymer demulsifier to the interface, accelerating the disruption and recombination of the interfacial film, and synergistically achieving efficient oil-water separation. Due to the presence of Fe3O4, the demulsifier interacts with the active substances on the oil-water interface film, and under the action of an external magnetic field, the oil droplets with the magnetic demulsifier attached can be aggregated together, thereby further improving the demulsification efficiency of the material. This demulsifier also has excellent recyclability, which not only improves material utilization and reduces demulsification costs, but also allows for easy separation of the demulsifier after demulsification, avoiding any impact on the properties of the oil or water phase.

[0026] 2. The demulsifier and its preparation method of this application have good oil solubility. The acrylate copolymer demulsifier molecules can rapidly diffuse in high-viscosity emulsions, reach the oil-water interface, and destroy the asphaltene-colloid interface film. The natural active substances on the surface of water droplets are replaced by the hydrophilic segments of the acrylate copolymer demulsifier. Then the water droplets aggregate together. When the water droplets are large enough, their gravity can overcome viscous resistance and buoyancy to sink, thus achieving oil-water separation. As the viscous resistance decreases, the size of the sinking water droplets becomes smaller and smaller, and demulsification continues until a small number of water droplets are difficult to aggregate. Detailed Implementation

[0027] The endpoints and any values ​​of the ranges disclosed herein are not limited to the precise ranges or values, and these ranges or values ​​should be understood to include values ​​close to these ranges or values. For numerical ranges, the endpoint values ​​of the various ranges, the endpoint values ​​of the various ranges and individual point values, and individual point values ​​can be combined with each other to obtain one or more new numerical ranges, which should be considered as specifically disclosed herein.

[0028] Unless otherwise specified in the examples, the procedures shall be performed under standard conditions or conditions recommended by the manufacturer. Raw materials or instruments whose manufacturers are not specified are all commercially available products.

[0029] Example 1

[0030] A method for preparing a demulsifier includes the following steps:

[0031] (1) Add ferric chloride hexahydrate, sodium acetate and polyethylene glycol in a weight ratio of 1.2:3:1 to ethylene glycol, mix evenly at 60°C, then add 70wt% ferric chloride hexahydrate bentonite and ultrasonically disperse for 20min, then react at 180°C for 30h, wash and dry to obtain magnetic bentonite.

[0032] (2) Magnetic bentonite was ultrasonically dispersed in toluene for 15 min, and (3-glycidylpropoxy)trimethoxysilane was added. The weight ratio of magnetic bentonite to (3-glycidylpropoxy)trimethoxysilane was 1:3.2. The mixture was stirred at 70 °C for 10 h, and then collected with a magnet, washed, and dried to obtain silanized magnetic bentonite.

[0033] (3) The silanized magnetic bentonite was ultrasonically dispersed in toluene for 15 min to obtain a silanized magnetic bentonite solution. The acrylate copolymer demulsifier and sodium lauryl hydroxyethyl sulfonate were dissolved in toluene, and then 76 wt% of 4-dimethylaminopyridine of silanized magnetic bentonite was added and ultrasonically dispersed for 10 min. Then it was added to the silanized magnetic bentonite solution and stirred at 85 °C for 6 h. The weight ratio of silanized magnetic bentonite, acrylate copolymer demulsifier and sodium lauryl hydroxyethyl sulfonate was 1:6:2.8. The demulsifier was separated and collected by a magnet, washed and dried to obtain a demulsifier with an average particle size of 26.90 nm.

[0034] The preparation method of the acrylate copolymer demulsifier includes:

[0035] N-hydroxymethylacrylamide, methyl acrylate, and 0.8 wt% azobisisobutyronitrile (AIBN) were placed in a reaction vessel and dissolved in toluene. The weight ratio of N-hydroxymethylacrylamide to methyl acrylate was 1:1.5. Nitrogen gas was then introduced, and the mixture was heated to 70°C and reacted for 15 hours. After the reaction was completed, the system was cooled to room temperature, washed, and dried to obtain the acrylate copolymer demulsifier with a weight-average molecular weight of 126,000 g / mol.

[0036] Example 2

[0037] A method for preparing a demulsifier includes the following steps:

[0038] (1) Add ferric chloride hexahydrate, sodium acetate and polyethylene glycol in a weight ratio of 1.5:3.5:1 to diethylene glycol, mix evenly at 70°C, then add 75wt% ferric chloride hexahydrate bentonite and ultrasonically disperse for 30 min, then react at 200°C for 24 h, wash and dry to obtain magnetic bentonite.

[0039] (2) Magnetic bentonite was ultrasonically dispersed in xylene for 20 min, and (3-glycidylpropoxy)methyldimethoxysilane was added. The weight ratio of magnetic bentonite to (3-glycidylpropoxy)methyldimethoxysilane was 1:4. The mixture was stirred at 80 °C for 8 h, and then collected with a magnet, washed, and dried to obtain silanized magnetic bentonite.

[0040] (3) The silanized magnetic bentonite was ultrasonically dispersed in xylene for 20 min to obtain a silanized magnetic bentonite solution. The acrylate copolymer demulsifier and sodium lignosulfonate were dissolved in xylene, and then 80 wt% of 4-dimethylaminopyridine of silanized magnetic bentonite was added and ultrasonically dispersed for 15 min. Then it was added to the silanized magnetic bentonite solution and stirred at 100℃ for 5 h. The weight ratio of silanized magnetic bentonite, acrylate copolymer demulsifier and sodium lignosulfonate was 1:6.7:3. The demulsifier was separated and collected by a magnet, washed and dried to obtain a demulsifier with an average particle size of 27.62 nm.

[0041] The preparation method of the acrylate copolymer demulsifier includes:

[0042] N-hydroxymethylacrylamide, butyl acrylate, and 1 wt% azobisisobutyronitrile (AIBN) were placed in a reaction vessel and dissolved in xylene. The weight ratio of N-hydroxymethylacrylamide to butyl acrylate was 1:2.2. Nitrogen gas was then introduced and the mixture was heated to 75°C and reacted for 10 hours. After the reaction was completed, the system was cooled to room temperature, washed, and dried to obtain the acrylate copolymer demulsifier with a weight-average molecular weight of 180,000 g / mol.

[0043] Example 3

[0044] A method for preparing a demulsifier includes the following steps:

[0045] (1) Add ferric chloride hexahydrate, sodium acetate and polyethylene glycol in a weight ratio of 1.7:4:1 to ethylene glycol, mix evenly at 80°C, then add 80wt% of ferric chloride hexahydrate bentonite and ultrasonically disperse for 40 min, then react at 250°C for 20 h, wash and dry to obtain magnetic bentonite.

[0046] (2) Magnetic bentonite was ultrasonically dispersed in toluene for 30 min, and (3-glycidylpropoxy)triethoxysilane was added. The weight ratio of magnetic bentonite to (3-glycidylpropoxy)triethoxysilane was 1:5. The mixture was stirred at 85 °C for 6 h, and then collected with a magnet, washed, and dried to obtain silanized magnetic bentonite.

[0047] (3) The silanized magnetic bentonite was ultrasonically dispersed in toluene for 30 min to obtain a silanized magnetic bentonite solution. The acrylate copolymer demulsifier and the coconut oil-based hydroxyethyl sulfonate sodium were dissolved in toluene. Then, 83 wt% of 4-dimethylaminopyridine of the silanized magnetic bentonite was added and ultrasonically dispersed for 20 min. Then, it was added to the silanized magnetic bentonite solution and stirred at 110 °C for 4 h. The weight ratio of silanized magnetic bentonite, acrylate copolymer demulsifier and coconut oil-based hydroxyethyl sulfonate sodium was 1:7.2:3.5. The demulsifier was separated and collected by a magnet, washed and dried to obtain a demulsifier with an average particle size of 28.51 nm.

[0048] The preparation method of the acrylate copolymer demulsifier includes:

[0049] N-hydroxymethylacrylamide, ethyl acrylate, and benzoyl peroxide (total weight 1.2 wt%) were placed in a reaction vessel and dissolved in toluene. The weight ratio of N-hydroxymethylacrylamide to ethyl acrylate was 1:3. Nitrogen gas was then introduced, and the mixture was heated to 80°C and reacted for 7 hours. After the reaction was completed, the system was cooled to room temperature, washed, and dried to obtain an acrylate copolymer demulsifier with a weight-average molecular weight of 200,000 g / mol.

[0050] Comparative Example 1

[0051] The difference from Example 2 is that the weight ratio of N-hydroxymethylacrylamide to butyl acrylate is 1:1.

[0052] Comparative Example 2

[0053] The difference from Example 2 is that step (3) is:

[0054] Silanized magnetic bentonite was ultrasonically dispersed in xylene for 20 min to obtain a silanized magnetic bentonite solution. An acrylate copolymer demulsifier was dissolved in xylene, and then 80 wt% of 4-dimethylaminopyridine of the silanized magnetic bentonite was added and ultrasonically dispersed for 15 min. This solution was then added to the silanized magnetic bentonite solution and stirred at 100 °C for 5 h. The weight ratio of silanized magnetic bentonite to acrylate copolymer demulsifier was 1:6.7. The solution was separated and collected using a magnet, washed, and dried to obtain the demulsifier with an average particle size of 27.62 nm.

[0055] Comparative Example 3

[0056] The difference from Example 2 is that the preparation method of the acrylate copolymer demulsifier is not disclosed, and step (3) is as follows:

[0057] Silanized magnetic bentonite was ultrasonically dispersed in xylene for 20 min to obtain a silanized magnetic bentonite solution. Sodium lignosulfonate was dissolved in xylene, and then 80 wt% of 4-dimethylaminopyridine of silanized magnetic bentonite was added and ultrasonically dispersed for 15 min. This solution was then added to the silanized magnetic bentonite solution and stirred at 100 °C for 5 h. The weight ratio of silanized magnetic bentonite to sodium lignosulfonate was 1:6.7:3. The solution was separated and collected using a magnet, washed, and dried to obtain a demulsifier with an average particle size of 27.62 nm.

[0058] Comparative Example 4

[0059] The difference from Example 2 is that step (3) and the preparation method of the acrylate copolymer demulsifier are not disclosed.

[0060] Comparative Example 5

[0061] The difference from Example 2 is that sodium lignosulfonate is replaced with Tween 80.

[0062] Comparative Example 6

[0063] The difference from Example 2 is that bentonite is replaced with montmorillonite.

[0064] Comparative Example 7

[0065] The difference from Example 2 is that 4-dimethylaminopyridine is replaced with triethylamine.

[0066] Performance testing

[0067] Crude oil from a block in the Shengli Oilfield was processed and dehydrated. The density of the dehydrated crude oil at 25℃ was 0.861 kg / m³. 3 The viscosity at 50℃ was 37.5 mPa·s, and the total water content was 0.7%. The crude oil emulsion used for demulsification was prepared in an experimental laboratory. Dehydrated crude oil and distilled water were heated separately in a 60℃ constant-temperature water bath. The preheated crude oil was placed in a stirrer, and distilled water was added in three batches, each time stirred at 2000 r / min for 90 min, to prepare an artificial crude oil emulsion. The prepared crude oil emulsion with a water content of 20% was poured into a beaker and allowed to stand at room temperature for 24 h. No oil-water separation was observed, and the emulsion was ready for use.

[0068] Demulsification performance evaluation: 20 mL of crude oil emulsion was added to the sample bottle, and then 300 mg / L of the demulsifier of Examples 1-3 and Comparative Examples 1-7 was added. The mixture was shaken at 40 °C for 2 min and allowed to stand for 90 min. The demulsification effect was then recorded.

[0069] Recycling performance evaluation: After each demulsification experiment, the demulsifier is recovered by applying an external magnetic field. The separated demulsifier is then washed and dried, and a new round of demulsification experiments is conducted. The above experimental process is repeated ten times to evaluate the recycling performance of the demulsifier.

[0070] The performance test results are shown in Table 1 below.

[0071] Table 1

[0072]

[0073] As shown in Table 1, the demulsifier prepared in this application has a good demulsification effect and a dehydration rate of over 97%. After ten cycles of demulsification-recovery-demulsification, the dehydration rate can still reach over 92%.

[0074] The above description is merely an embodiment of this application, and the scope of protection of this application is not limited to these specific embodiments, but is determined by the claims of this application. Various modifications and variations can be made to this application by those skilled in the art. Any modifications, equivalent substitutions, improvements, etc., made within the technical concept and principles of this application should be included within the scope of protection of this application.

Claims

1. A method for preparing a demulsifier, characterized in that, Includes the following steps: (1) Add ferric chloride hexahydrate, sodium acetate and polyethylene glycol in a weight ratio of (1.2-1.7):(3-4):1 to a polyol solvent, mix evenly at 60-80℃, then add 70-80wt% of ferric chloride hexahydrate bentonite and ultrasonically disperse for 20-40min, then react at 180-250℃ for 20-30h, wash and dry to obtain magnetic bentonite; (2) Disperse the magnetic bentonite in an organic solvent by ultrasonication for 15-30 min, add a silane coupling agent, the weight ratio of magnetic bentonite to silane coupling agent is 1:(3.2-5), stir at 70-85℃ for 6-10 h, then collect with a magnet, wash, dry, and obtain silanized magnetic bentonite. (3) Disperse silanized magnetic bentonite in an organic solvent by ultrasonication for 15-30 min to obtain a silanized magnetic bentonite solution. Dissolve acrylate copolymer demulsifier and sulfonate demulsifier in an organic solvent. The weight ratio of silanized magnetic bentonite, acrylate copolymer demulsifier and sulfonate demulsifier is 1:(6-7.2):(2.8-3.5). Then add 76-83wt% of 4-dimethylaminopyridine to silanized magnetic bentonite and disperse by ultrasonication for 10-20 min. Then add it to the silanized magnetic bentonite solution and stir at 85-110℃ for 4-6 h. Separate and collect with a magnet, wash and dry to obtain the demulsifier. The preparation method of the acrylate copolymer demulsifier includes: N-hydroxymethylacrylamide, alkyl acrylate, and 0.8-1.2 wt% of the total weight of the monomers initiator are placed in a reaction vessel, dissolved in an organic solvent, and then an inert gas is introduced. The mixture is heated to 70-80℃ and reacted for 7-15 hours. After the reaction is completed, the system is cooled to room temperature, washed, and dried to obtain the acrylate copolymer demulsifier. The sulfonate demulsifier is sodium lauryl hydroxyethyl sulfonate, sodium cocoyl hydroxyethyl sulfonate, or sodium lignin sulfonate.

2. The preparation method according to claim 1, characterized in that, The polyol solvent is ethylene glycol or diethylene glycol; And / or, the silane coupling agent is (3-glycidylpropoxy)trimethoxysilane, (3-glycidylpropoxy)triethoxysilane, or (3-glycidylpropoxy)methyldimethoxysilane.

3. The preparation method according to claim 1, characterized in that, The weight ratio of N-hydroxymethylacrylamide to alkyl acrylate is 1:(1.5-3).

4. The preparation method according to claim 1, characterized in that, The alkyl acrylate is methyl acrylate, ethyl acrylate or butyl acrylate; And / or, the initiator is azobisisobutyronitrile or benzoyl peroxide; And / or, the organic solvent is toluene or xylene.

5. A demulsifier, characterized in that, The demulsifier is prepared by the preparation method described in any one of claims 1-4.

Images