Magnetic reduced graphene oxide nanodemulsifier, preparation method and use

Abstract

The application relates to a magnetic reduced graphene oxide nanometer demulsifier, a preparation method and use, the preparation method comprises the following steps: step 1, graphene oxide is prepared into a graphene oxide aqueous solution; step 2, a soluble iron salt is prepared into a soluble iron salt aqueous solution; step 3, the graphene oxide aqueous solution is added dropwise into the soluble iron salt aqueous solution, and a magnetic reduced graphene oxide nanometer demulsifier is obtained by reaction of the two. The magnetic reduced graphene oxide nanometer demulsifier is prepared by a simple synthesis method, the demulsifier needs a small dosage in a demulsification process, efficient separation of poly-containing aged oil is realized under a low dosage condition, and the problems of large dosage and low demulsification efficiency of an existing demulsifier are solved. The raw material of the magnetic reduced graphene oxide nanometer demulsifier is widely sourced, cheap and easy to obtain, the demulsifier has magnetism, is easy to recycle, the utilization rate is improved, and the demulsification efficiency of the demulsifier is still higher than 90% after 5 cycles of utilization.

Description

Technical Field

[0001] This invention relates to the field of inorganic nanomaterials, and in particular to a magnetic reduction graphene oxide nano-demulsifier, its preparation method, and its uses. Background Technology

[0002] Approximately 8 million tons of polymer-containing aged oil are produced annually in oilfields nationwide. Due to the injection of polymers into crude oil during the later stages of oilfield development and heavy oil production to promote the flow of oil-water mixtures, aged oil also contains a significant amount of polymers. This polymer-containing aged oil exhibits high viscosity, high interfacial film strength, good stability, and severe emulsification. During production, it can cause dehydration systems to malfunction, leading to substandard wastewater quality. Furthermore, the blurred oil-water interface, under the influence of an electric field, can cause accidents such as short-circuit tripping of the electrostatic dehydrator. Current technologies for demulsifying polymer-containing aged oil typically include electro-demulsification, physical demulsification, and chemical demulsification.

[0003] CN116103058A discloses an electric field demulsifier, comprising an electric field demulsification section, an inlet section for the inflow of emulsion, and an outlet section for the outflow of emulsion. The electric field demulsification section includes a casing, within which are grounded electrode plates and high-voltage insulating electrodes electrically connected to a power source. Enclosed independent spaces are formed between the grounded electrode plates and the casing, and between adjacent grounded electrode plates, creating fluid channels. At least one high-voltage insulating electrode is installed in each independent space. These high-voltage insulating electrodes are spaced apart from the casing and the grounded electrode plates. The fluid channels are connected to the inlet and outlet sections. This electric field demulsifier results in a more uniform electric field distribution. Under appropriate turbulence and a high-voltage electric field, the dispersed phase water particles aggregate and collide, increasing their particle size and improving the demulsification effect.

[0004] CN103408153A discloses a physical demulsification treatment device and method for emulsified oily wastewater. After sedimentation separation in a settling tank, the emulsified oily wastewater from the oilfield undergoes online demulsification using a porous plate demulsification system. The resulting tiny oil droplets are then coalesced and separated using an oil-water coalescing system. The floated oil after coalescing can be recovered. The treated oily wastewater is further separated using a tubular membrane cross-flow system. The device features a simple structure, convenient maintenance, and high treatment efficiency.

[0005] For chemical demulsification of aged oils containing polyols, demulsifiers can be used, which requires no complex equipment, is simple to operate, and has a short processing time. Conventional demulsifiers include polyol block polyethers, polyethylene polyamine block polyethers, and phenolic amine resin block polyether demulsifiers. However, for highly stable aged oils containing polyols, the dosage of conventional demulsifiers required is large, and the operation and material usage are complex.

[0006] CN102030878A discloses a method for preparing an oilfield demulsifier, using polyethylene polyamine as a raw material, which is obtained through crosslinking modification after reaction with ethylene oxide and propylene oxide. First, polyethylene polyamine is used as an initiator to react with propylene oxide and ethylene oxide in the presence of an alkaline catalyst to prepare a polyethylene polyamine-type polyether demulsifier. Then, under the action of a catalyst, polycarboxylic acid is used to perform a self-crosslinking reaction on polyether demulsifier A to obtain product B. Finally, polyether demulsifier A and product B are subjected to a self-crosslinking reaction with toluene diisocyanate in a solvent to obtain the final product, a high-performance demulsifier. This demulsifier has a relatively high molecular weight, ideal dehydration effect, and good broad-spectrum activity; however, the synthesis process uses TDI, which is highly toxic to humans, as a crosslinking agent and xylene as a solvent, increasing costs and causing environmental pollution.

[0007] Graphene oxide possesses characteristics such as high specific surface area, low surface energy, and low density. It exhibits excellent dispersion stability in water and most polar organic solvents and is non-toxic and harmless. Its surface has numerous carboxyl and hydroxyl groups, giving it hydrophilicity, while its internal aromatic ring planes are hydrophobic. Therefore, it can be considered a two-dimensional surface-active material and can be used in demulsifiers.

[0008] CN110639240A discloses a method for preparing a magnetic inorganic clay-graphene composite demulsifier for the separation of oil-in-water crude oil emulsions. However, this method involves a complex preparation process, high reaction temperatures, and requires a large concentration during demulsification, resulting in high costs and limiting its widespread application. Therefore, existing modified graphene composite demulsifiers suffer from several drawbacks in crude oil emulsion separation, including complex preparation processes, large dosage requirements, and inability to achieve efficient separation of complex, polymer-containing, aged oils.

[0009] Compared to graphene oxide, reduced graphene oxide can further adjust its hydrophilicity and oleophilicity, and its π-π interaction with asphaltene molecules is stronger than that of graphene oxide. This makes the protective film of the stable emulsion easier to be destroyed, thereby promoting oil droplet aggregation and achieving oil-water separation.

[0010] CN110482533B discloses a reduced graphene oxide / nano-TiO2 composite demulsifier and its preparation method. The method involves surface modification of graphene oxide with nano-TiO2 generated from the in-situ hydrolysis of an organotitanium precursor, followed by hydrothermal reduction to obtain the reduced graphene oxide / nano-TiO2 composite demulsifier. The resulting reduced graphene oxide / nano-TiO2 composite demulsifier is highly efficient and environmentally friendly, causing no pollution to the environment. It is suitable for neutral and acidic conditions and exhibits high salt resistance. Furthermore, after demulsification, the demulsifier can transfer to the oil phase, avoiding its retention in the aqueous phase and thus preventing its subsequent use.

[0011] However, graphene particles are small in size, making them difficult to filter and precipitate. The recycling process is cumbersome and costly. Therefore, a simple recycling method is needed to achieve rapid separation of reduced graphene oxide composite nano-demulsifiers. Combining reduced graphene oxide with magnetic nanoparticles can impart magnetic responsiveness to the demulsifier, enabling its effective separation from aged oil.

[0012] CN113913212A discloses a method for preparing a green fluorinated magnetic demulsifier. This magnetic demulsifier is synthesized by grafting hyperbranched fluorinated polyether onto the surface of magnetic Fe3O4 nanoparticles. The surfactant is mainly adsorbed onto the surface of Fe3O4 through electrostatic and covalent bonds. Fe3O4 nanoparticles themselves possess demulsification capabilities, and combined with their magnetic properties, they are a demulsifier with great development potential. However, due to their inherent structure, they are prone to aggregation. Therefore, a novel magnetic demulsifier is prepared by combining them with fluorinated polyether. The resulting demulsifier exhibits good demulsification performance, but the reaction process requires high-temperature treatment, and dibenzyl ether easily decomposes at room temperature, resulting in harsh synthesis conditions.

[0013] Therefore, it is an urgent technical problem to be solved to prepare a highly efficient demulsifier that is easy to recycle and can be used in low doses using simple preparation methods and low-cost synthetic raw materials. Summary of the Invention

[0014] To address the above problems, this invention provides a magnetically reduced graphene oxide nano-demulsifier. The preparation process requires no heating and has a short reaction time. It is used for efficient and rapid oil-water separation of aged oils containing polymers, and can be recycled using a magnet. Therefore, the invention of this magnetically reduced graphene oxide nano-demulsifier is of significant importance in this field.

[0015] This invention provides a magnetic reduced graphene oxide nano-demulsifier, which utilizes a redox reaction between a soluble iron salt and graphene oxide. The soluble iron salt is oxidized to iron(III) oxide (Fe3O4), and the graphene oxide is reduced to reduced graphene oxide, forming the magnetic reduced graphene oxide nano-demulsifier. The iron(III) oxide nanoparticles have a particle size of 15-25 nm, and the reduced graphene oxide exhibits a layered, wrinkled state. The iron(III) oxide is attached to the surface or layered wrinkles of the reduced graphene oxide. In X-ray diffraction, the magnetic reduced graphene oxide nano-demulsifier shows characteristic peaks at diffraction angles 2θ of 30.1°±0.02°, 35.5°±0.02°, 43.1°±0.02°, 53.5°±0.02°, 57.0°±0.02°, and 62.6°±0.02°.

[0016] The preparation method of the magnetic reduced graphene oxide nano-demulsifier of the present invention includes the following steps:

[0017] Step 1: Mix graphene oxide with water to prepare a mixed solution. After ultrasonic dispersion, adjust the pH value with an alkaline solution to obtain mixed solution A.

[0018] Step 2: Mix the soluble iron salt with water to prepare mixed solution B;

[0019] Step 3: Add the mixed solution B dropwise to the mixed solution A, and stir at the reaction temperature to obtain a mixture C containing crude solid magnetic reduced graphene oxide nano-demulsifier;

[0020] Step 4: Filter the crude magnetic reduced graphene oxide nano-demulsifier in the mixture C, wash it with solvent, and then dry it in an oven to obtain the finished magnetic reduced graphene oxide nano-demulsifier.

[0021] Furthermore, based on the mass of the soluble iron salt, the mass ratio of the soluble iron salt to the graphene oxide in the magnetic reduced graphene oxide nano-demulsifier is (10-500):1.

[0022] Furthermore, in step 1, the concentration of graphene oxide in mixed solution A is 0.01-10.0 wt%.

[0023] Furthermore, the ultrasound time in step 1 is 0.5-2 hours.

[0024] Furthermore, in step 1, the alkaline solution is ammonia or a 1 mol / L sodium hydroxide solution, and the pH value is adjusted to a range of 7.5-13.5.

[0025] Furthermore, in step 2, the concentration of the soluble iron salt in the mixed solution B is 0.1 wt% to 25.0 wt%.

[0026] Furthermore, the soluble iron salt in step 2 is one or more of ferrous chloride tetrahydrate, ferrous chloride hexahydrate, and ferrous sulfate.

[0027] Furthermore, in step 3, the rate at which mixed solution B is added to mixed solution A is 3-5 seconds per drop.

[0028] Furthermore, in step 3, the reaction temperature is 20-50℃, the reaction time is 1-48h, and the stirring speed is 500-1000r / min.

[0029] Furthermore, in step 3, the carboxyl groups on the surface of the graphene oxide in the mixed solution A are relatively weak. Adjusting the pH to alkaline conditions makes more carboxyl groups active, improves the hydrophilicity of the graphene oxide, and makes the graphene oxide react more easily with iron ions.

[0030] Furthermore, in step 4, the solvent is one or both of deionized water and anhydrous ethanol, and the washing is performed 3-5 times.

[0031] Furthermore, in step 4, the drying temperature is 45-85℃, and the drying time is 24-48h.

[0032] The present invention describes the use of the magnetic reduced graphene oxide nano-demulsifier, which is used to demulsify polymer-containing aged oil. The polymer-containing aged oil includes asphaltenes and gum-like non-hydrocarbon compounds. The reduced graphene oxide in the magnetic reduced graphene oxide nano-demulsifier interacts with the asphaltenes and gums through electrostatic and π-π stacking interactions, thereby destroying the oil-water interface film of the polymer-containing aged oil and obtaining an aqueous phase and an oil phase.

[0033] The application of the magnetic reduced graphene oxide nano-demulsifier of the present invention includes the following demulsification steps:

[0034] Step 1: Weigh the magnetic reduced graphene oxide nano-demulsifier and add it to the polymer-containing aged oil;

[0035] Step 2: Demulsify the aged oil containing polymer according to the bottle test method. After demulsification, let it stand to obtain the oil phase and the water phase. The magnetic reduced graphene oxide nano-demulsifier after demulsification exists in the water phase. The demulsification rate of the demulsifier is obtained by detecting the dehydration rate of the aged oil containing polymer.

[0036] Step 3: Filter and separate the magnetic reduced graphene oxide nano-demulsifier in the aqueous phase obtained in Step 2, wash it with an organic solvent until the washing liquid is colorless, dry it at a constant temperature and then recover it for later use.

[0037] Step 4: Using the magnetic reduced graphene oxide nano-demulsifier recovered in Step 3, the polymer-containing aged oil is repeatedly demulsified, and the demulsification rate of the demulsifier is obtained by detecting the dehydration rate of the polymer-containing aged oil.

[0038] Furthermore, in step 1, the concentration of the reduced graphene oxide nano-demulsifier in the polymer-containing aged oil is 0.002-0.2 wt%.

[0039] Furthermore, in step 2, the bottle test method involves adding a demulsifier to the aged oil containing polymer, performing demulsification during the mixing process, and allowing it to stand after thorough mixing to obtain a clear oil-water interface film.

[0040] Furthermore, in step 2, the initial demulsification rate of the magnetically reduced graphene oxide nano-demulsifier is 90-100%.

[0041] Furthermore, in step 2, the demulsification temperature is 10-100℃, and the standing time is 1-2 hours.

[0042] Furthermore, in step 3, the organic solvent is one or more of toluene and petroleum ether, the constant temperature drying temperature is 60-80℃, and the constant temperature drying time is 24-48h.

[0043] Furthermore, the demulsification rate of the magnetic reduced graphene oxide nano-demulsifier recovered in step 4, which can be reused 2-5 times, is 85%-100%.

[0044] The beneficial effects of this invention are:

[0045] 1. This invention utilizes the oxidation properties of graphene oxide itself to synthesize a magnetically reduced graphene oxide nano-demulsifier in one step. The reaction process does not require heating, and the method is simple and quick.

[0046] 2. The soluble iron salt used in the magnetic reduced graphene oxide nano-demulsifier of the present invention is widely available, inexpensive and readily available;

[0047] 3. The ferric oxide of the present invention has a small particle size and good dispersibility, which enables efficient separation of polymer-containing aged oil under low dosage conditions, and solves the problems of large dosage and low demulsification efficiency of existing demulsifiers.

[0048] 4. The magnetic reduced graphene oxide nano-demulsifier of the present invention has excellent demulsification performance under different temperature conditions. Moreover, with the increase of the dosage of the demulsifier, the demulsification efficiency of the polymer-containing aged oil gradually increases, the oil-water interface is clear, and the aqueous phase is clear.

[0049] 5. The magnetic reduced graphene oxide nano-demulsifier of the present invention has magnetic recyclable characteristics, which improves its utilization rate, solves the problems of high demulsifier treatment cost and environmental pollution, and reduces the impact of demulsifier on aqueous and oil phase pollution.

[0050] 6. The magnetic reduced graphene oxide nano-demulsifier of the present invention still has a demulsification efficiency of more than 85% after 5 cycles, realizing the cycle stability of demulsification performance and greatly reducing the demulsification cost. Attached Figure Description

[0051] Figure 1 This is the X-ray diffraction pattern of the magnetic reduced graphene oxide nano-demulsifier of Example 1 of the present invention;

[0052] Figure 2 This is a scanning electron microscope image of the magnetic reduced graphene oxide nano-demulsifier of Example 1 of the present invention;

[0053] Figure 3 The diagram shows the effect of the magnetic reduced graphene oxide nano-demulsifier of Example 1 of the present invention on the demulsification of aged oil containing polymers.

[0054] Figure 4This is a statistical chart showing the demulsification rate of the magnetic reduced graphene oxide nano-demulsifier of Example 3 of the present invention on repeated demulsification of aged oil containing polymers.

[0055] Figure 5 This is a comparative graph showing the effect of the concentration of the magnetic reduced graphene oxide nano-demulsifier of this invention on the demulsification rate of aged oil containing polymer. Detailed Implementation

[0056] The invention will be described in detail below with reference to the embodiments:

[0057] This invention provides a magnetic reduced graphene oxide nano-demulsifier, its preparation method, and its uses. The preparation process is simple, the raw materials are readily available, and the resulting demulsifier is highly efficient and requires only a small amount, which greatly improves its demulsification performance on polymer-containing aged oils.

[0058] Example 1

[0059] This embodiment describes a method for preparing a magnetically reduced graphene oxide nano-demulsifier, comprising the following steps:

[0060] Step 1: Mix graphene oxide with water to prepare a mixed solution with a concentration of 0.01 wt%. After ultrasonic dispersion for 0.5 h, adjust the pH of the mixed solution to 9.0 with 1 mol / L NaOH solution to obtain mixed solution A.

[0061] Step 2: Mix ferrous chloride tetrahydrate with water to prepare a mixed solution B with a concentration of 0.1 wt%.

[0062] Step 3: At 25°C, 50 mL of the mixed solution B is added dropwise to 20 mL of the mixed solution A, and the mixture is stirred at 500 r / min for 1 h to obtain a mixture C containing crude solid magnetic reduced graphene oxide nano-demulsifier.

[0063] Step 4: Filter the crude magnetic reduced graphene oxide nano-demulsifier in the mixture C, wash it 3-5 times with deionized water and anhydrous ethanol, and then dry it in an oven at 60°C for 48 hours to obtain the finished magnetic reduced graphene oxide nano-demulsifier.

[0064] like Figure 1 The image shown is an X-ray diffraction pattern of this embodiment, where Fe3O4-rGO represents magnetic reduced graphene oxide nano-demulsifier, rGO represents reduced graphene oxide, and Fe3O4 represents iron(II,III) oxide.

[0065] like Figure 2 The image shown is a scanning electron microscope (SEM) image of the magnetic reduced graphene oxide nano-demulsifier of this embodiment.

[0066] The application of a magnetically reduced graphene oxide nano-demulsifier in this embodiment includes the following steps:

[0067] Step 1: Weigh 0.015g of magnetic reduced graphene oxide nano-demulsifier and add it to 40.0g of polymer-containing aged oil;

[0068] Step 2: At 25℃, the magnetic reduced graphene oxide nano-demulsifier is thoroughly mixed with the polymer-containing aged oil, and then allowed to stand for 2 hours to obtain a clear oil-water interface film, such as... Figure 3 The figure shown is a graph illustrating the effect of the concentration of magnetic reduced graphene oxide nano-demulsifier on the demulsification of polymer-containing aged oil in this embodiment. The magnetic reduced graphene oxide nano-demulsifier after demulsification exists in the aqueous phase. The demulsification rate of the demulsifier was 92.6% by detecting the dehydration rate of the polymer-containing aged oil.

[0069] Step 3: Filter and separate the magnetic reduced graphene oxide nano-demulsifier in the aqueous phase obtained in Step 2, and wash it with toluene and petroleum ether until the washing liquid is colorless. After drying at 60℃ for 48 hours, it is recovered for later use.

[0070] Step 4: Using the magnetic reduced graphene oxide nano-demulsifier recovered in Step 3, the aged oil containing polymer is repeatedly demulsified. After being used 5 times, the demulsification rate of the demulsifier is higher than 90%.

[0071] Example 2

[0072] This embodiment describes a method for preparing a magnetically reduced graphene oxide nano-demulsifier, comprising the following steps:

[0073] Step 1: Mix graphene oxide with water to prepare a mixed solution with a concentration of 0.1 wt%. After ultrasonic dispersion for 1.0 h, adjust the pH of the mixed solution to 10.0 with 1 mol / L NaOH solution to obtain mixed solution A.

[0074] Step 2: Mix ferrous chloride tetrahydrate with water to prepare a mixed solution B with a concentration of 2.5 wt%.

[0075] Step 3: At 80°C, 50 mL of the mixed solution B is added dropwise to 20 mL of the mixed solution A, and the mixture is stirred at 500 r / min for 3 h to obtain a mixture C containing crude solid magnetic reduced graphene oxide nano-demulsifier.

[0076] Step 4: Filter the crude magnetic reduced graphene oxide nano-demulsifier in the mixture C, wash it 3-5 times with deionized water and anhydrous ethanol, and then dry it in an oven at 60°C for 48 hours to obtain the finished magnetic reduced graphene oxide nano-demulsifier.

[0077] The application of a magnetically reduced graphene oxide nano-demulsifier in this embodiment includes the following steps:

[0078] Step 1: Weigh 0.03g of magnetic reduced graphene oxide nano-demulsifier and add it to 40.0g of aged oil containing polymer;

[0079] Step 2: At 25°C, the magnetic reduced graphene oxide nano-demulsifier was thoroughly mixed with the polymer-containing aged oil and allowed to stand for 2 hours to obtain a clear oil-water interface film. The demulsified magnetic reduced graphene oxide nano-demulsifier was present in the aqueous phase. The demulsification rate of the demulsifier was 98.4% by detecting the dehydration rate of the polymer-containing aged oil.

[0080] Step 3: Filter and separate the magnetic reduced graphene oxide nano-demulsifier in the aqueous phase obtained in Step 2, and wash it with toluene and petroleum ether until the washing liquid is colorless. After drying at 60℃ for 48 hours, it is recovered for later use.

[0081] Step 4: Using the magnetic reduced graphene oxide nano-demulsifier recovered in Step 3, the aged oil containing polymer is repeatedly demulsified. After being used 5 times, the demulsification rate of the demulsifier is higher than 90%.

[0082] Example 3

[0083] This embodiment describes a method for preparing a magnetically reduced graphene oxide nano-demulsifier, comprising the following steps:

[0084] Step 1: Mix graphene oxide with water to prepare a mixed solution with a concentration of 0.02 wt%. After ultrasonic dispersion for 0.5 h, adjust the pH of the mixed solution to 7.5 with 1 mol / L NaOH solution to obtain mixed solution A.

[0085] Step 2: Mix ferrous chloride tetrahydrate with water to prepare a mixed solution B with a concentration of 0.25 wt%.

[0086] Step 3: At 60°C, 50 mL of the mixed solution B is added dropwise to 20 mL of the mixed solution A, and the mixture is stirred at 500 r / min for 20 h to obtain a mixture C containing crude solid magnetic reduced graphene oxide nano-demulsifier.

[0087] Step 4: Filter the crude magnetic reduced graphene oxide nano-demulsifier in the mixture C, wash it 3-5 times with deionized water and anhydrous ethanol, and then dry it in an oven at 60°C for 48 hours to obtain the finished magnetic reduced graphene oxide nano-demulsifier.

[0088] The application of a magnetically reduced graphene oxide nano-demulsifier in this embodiment includes the following steps:

[0089] Step 1: Weigh 0.05g of magnetic reduced graphene oxide nano-demulsifier and add it to 40.0g of aged oil containing polymer.

[0090] Step 2: Under the condition of 40℃, the magnetic reduced graphene oxide nano-demulsifier was thoroughly mixed with the polymer-containing aged oil and allowed to stand for 2 hours to obtain a clear oil-water interface film. The demulsified magnetic reduced graphene oxide nano-demulsifier was present in the aqueous phase. The demulsification rate of the demulsifier was 93.9% by detecting the dehydration rate of the polymer-containing aged oil.

[0091] Step 3: Filter and separate the magnetic reduced graphene oxide nano-demulsifier in the aqueous phase obtained in Step 2, and wash it with toluene and petroleum ether until the washing liquid is colorless. After drying at 60℃ for 48 hours, it is recovered for later use.

[0092] Step 4: Using the magnetically reduced graphene oxide nano-demulsifier recovered in Step 3, repeat the demulsification process on the polymer-containing aged oil, such as... Figure 4 The figure shows the demulsification rate of the magnetic reduced graphene oxide nano-demulsifier of this embodiment on the repeated demulsification of aged oil containing polyurethane. The vertical axis represents the dehydration rate (%), and the horizontal axis represents the number of cycles. After being used 5 times, the demulsification rate of the demulsifier is higher than 90%.

[0093] Example 4

[0094] This embodiment describes a method for preparing a magnetically reduced graphene oxide nano-demulsifier, comprising the following steps:

[0095] Step 1: Mix graphene oxide with water to prepare a mixed solution with a concentration of 0.15 wt%. After ultrasonic dispersion for 0.5 h, adjust the pH of the mixed solution to 11.0 with 1 mol / L NaOH solution to obtain mixed solution A.

[0096] Step 2: Mix ferrous chloride tetrahydrate with water to prepare a mixed solution B with a concentration of 0.25 wt%.

[0097] Step 3: At 25°C, 50 mL of the mixed solution B is added dropwise to 20 mL of the mixed solution A, and the mixture is stirred at 500 r / min for 3 h to obtain a mixture C containing crude solid magnetic reduced graphene oxide nano-demulsifier.

[0098] Step 4: Filter the crude magnetic reduced graphene oxide nano-demulsifier in the mixture C, wash it 3-5 times with deionized water and anhydrous ethanol, and then dry it in an oven at 80°C for 24 hours to obtain the finished magnetic reduced graphene oxide nano-demulsifier.

[0099] The application of a magnetically reduced graphene oxide nano-demulsifier in this embodiment includes the following steps:

[0100] Step 1: Weigh 0.011g of magnetic reduced graphene oxide nano-demulsifier and add it to 40.0g of aged oil containing polymer.

[0101] Step 2: At 80℃, the magnetic reduced graphene oxide nano-demulsifier was thoroughly mixed with the polymer-containing aged oil and allowed to stand for 2 hours to obtain a clear oil-water interface film. The demulsified magnetic reduced graphene oxide nano-demulsifier was present in the aqueous phase. The demulsification rate of the demulsifier was 98.6% by detecting the dehydration rate of the polymer-containing aged oil.

[0102] Step 3: Filter and separate the magnetic reduced graphene oxide nano-demulsifier in the aqueous phase obtained in Step 2, and wash it with toluene and petroleum ether until the washing liquid is colorless. After drying at 70℃ for 24 hours, it is recovered for later use.

[0103] Step 4: Using the magnetic reduced graphene oxide nano-demulsifier recovered in Step 3, the aged oil containing polymer is repeatedly demulsified. After being used 5 times, the demulsification rate of the demulsifier is higher than 90%.

[0104] Example 5

[0105] This embodiment describes a method for preparing a magnetically reduced graphene oxide nano-demulsifier, comprising the following steps:

[0106] Step 1: Mix graphene oxide with water to prepare a mixed solution with a concentration of 1.5 wt%. After ultrasonic dispersion for 0.5 h, adjust the pH of the mixed solution to 12.0 with 1 mol / L NaOH solution to obtain mixed solution A.

[0107] Step 2: Mix ferrous chloride tetrahydrate with water to prepare a mixed solution B with a concentration of 25.0 wt%.

[0108] Step 3: At 25°C, 50 mL of the mixed solution B is added dropwise to 20 mL of the mixed solution A, and the mixture is stirred at 500 r / min for 3 h to obtain a mixture C containing crude solid magnetic reduced graphene oxide nano-demulsifier.

[0109] Step 4: Filter the crude magnetic reduced graphene oxide nano-demulsifier in the mixture C, wash it 3-5 times with deionized water and anhydrous ethanol, and then dry it in an oven at 80°C for 24 hours to obtain the finished magnetic reduced graphene oxide nano-demulsifier.

[0110] The application of a magnetically reduced graphene oxide nano-demulsifier in this embodiment includes the following steps:

[0111] Step 1: Weigh 0.013g of magnetic reduced graphene oxide nano-demulsifier and add it to 40.0g of aged oil containing polymer.

[0112] Step 2: At 80℃, the magnetic reduced graphene oxide nano-demulsifier was thoroughly mixed with the polymer-containing aged oil and allowed to stand for 2 hours to obtain a clear oil-water interface film. The demulsified magnetic reduced graphene oxide nano-demulsifier was present in the aqueous phase. The demulsification rate of the demulsifier was 98.6% by detecting the dehydration rate of the polymer-containing aged oil.

[0113] Step 3: Filter and separate the magnetic reduced graphene oxide nano-demulsifier in the aqueous phase obtained in Step 2, and wash it with toluene and petroleum ether until the washing liquid is colorless. After drying at 70℃ for 24 hours, it is recovered for later use.

[0114] Step 4: Using the magnetic reduced graphene oxide nano-demulsifier recovered in Step 3, the aged oil containing polymer is repeatedly demulsified. After being used 5 times, the demulsification rate of the demulsifier is higher than 90%.

[0115] Example 6

[0116] This embodiment describes a method for preparing a magnetically reduced graphene oxide nano-demulsifier, comprising the following steps:

[0117] Step 1: Mix graphene oxide with water to prepare a mixed solution with a concentration of 0.015 wt%. After ultrasonic dispersion for 0.5 h, adjust the pH of the mixed solution to 13.5 with 1 mol / L NaOH solution to obtain mixed solution A.

[0118] Step 2: Mix ferrous chloride tetrahydrate with water to prepare a mixed solution B with a concentration of 25.0 wt%.

[0119] Step 3: At 25°C, 50 mL of the mixed solution B is added dropwise to 20 mL of the mixed solution A, and the mixture is stirred at 500 r / min for 3 h to obtain a mixture C containing crude solid magnetic reduced graphene oxide nano-demulsifier.

[0120] Step 4: Filter the crude magnetic reduced graphene oxide nano-demulsifier in the mixture C, wash it 3-5 times with deionized water and anhydrous ethanol, and then dry it in an oven at 80°C for 24 hours to obtain the finished magnetic reduced graphene oxide nano-demulsifier.

[0121] The application of a magnetically reduced graphene oxide nano-demulsifier in this embodiment includes the following steps:

[0122] Step 1: Weigh 0.010g of magnetic reduced graphene oxide nano-demulsifier and add it to 40.0g of polymer-containing aged oil;

[0123] Step 2: At 80℃, the magnetic reduced graphene oxide nano-demulsifier was thoroughly mixed with the polymer-containing aged oil and allowed to stand for 2 hours to obtain a clear oil-water interface film. The demulsified magnetic reduced graphene oxide nano-demulsifier was present in the aqueous phase. The demulsification rate of the demulsifier was 98.6% by detecting the dehydration rate of the polymer-containing aged oil.

[0124] Step 3: Filter and separate the magnetic reduced graphene oxide nano-demulsifier in the aqueous phase obtained in Step 2, and wash it with toluene and petroleum ether until the washing liquid is colorless. After drying at 70℃ for 24 hours, it is recovered for later use.

[0125] Step 4: Using the magnetic reduced graphene oxide nano-demulsifier recovered in Step 3, the aged oil containing polymer is repeatedly demulsified. After being used 5 times, the demulsification rate of the demulsifier is higher than 90%.

[0126] Example 7

[0127] This embodiment describes a method for preparing a magnetically reduced graphene oxide nano-demulsifier, comprising the following steps:

[0128] Step 1: Mix graphene oxide with water to prepare a mixed solution with a concentration of 4.0 wt%. After ultrasonic dispersion for 0.5 h, adjust the pH of the mixed solution to 8.0 with 1 mol / L NaOH solution to obtain mixed solution A.

[0129] Step 2: Mix ferrous chloride tetrahydrate with water to prepare a mixed solution B with a concentration of 20.0 wt%.

[0130] Step 3: At 25°C, 50 mL of the mixed solution B is added dropwise to 20 mL of the mixed solution A, and the mixture is stirred at 500 r / min for 3 h to obtain a mixture C containing crude solid magnetic reduced graphene oxide nano-demulsifier.

[0131] Step 4: Filter the crude magnetic reduced graphene oxide nano-demulsifier in the mixture C, wash it 3-5 times with deionized water and anhydrous ethanol, and then dry it in an oven at 80°C for 24 hours to obtain the finished magnetic reduced graphene oxide nano-demulsifier.

[0132] The application of a magnetically reduced graphene oxide nano-demulsifier in this embodiment includes the following steps:

[0133] Step 1: Weigh 0.0125g of magnetic reduced graphene oxide nano-demulsifier and add it to 40.0g of aged oil containing polymer.

[0134] Step 2: At 80℃, the magnetic reduced graphene oxide nano-demulsifier was thoroughly mixed with the polymer-containing aged oil and allowed to stand for 2 hours to obtain a clear oil-water interface film. The demulsified magnetic reduced graphene oxide nano-demulsifier was present in the aqueous phase. The demulsification rate of the demulsifier was 98.6% by detecting the dehydration rate of the polymer-containing aged oil.

[0135] Step 3: Filter and separate the magnetic reduced graphene oxide nano-demulsifier in the aqueous phase obtained in Step 2, and wash it with toluene and petroleum ether until the washing liquid is colorless. After drying at 70℃ for 24 hours, it is recovered for later use.

[0136] Step 4: Using the magnetic reduced graphene oxide nano-demulsifier recovered in Step 3, the aged oil containing polymer is repeatedly demulsified. After being used 5 times, the demulsification rate of the demulsifier is higher than 85%.

[0137] The demulsification rates obtained in Examples 1-7 are plotted as follows: Figure 5 The graph shows the effect of magnetic reduced graphene oxide nano-demulsifier concentration on the demulsification rate of aged oil containing polymers. CFE3O4-rGO (%) represents the concentration of the demulsifier. The comparison shows that the demulsification rate of the magnetic reduced graphene oxide nano-demulsifier prepared in this invention is higher than 90%.

[0138] Comparative Example 1

[0139] The application of a magnetic graphene oxide nano-demulsifier in this comparative example includes the following steps:

[0140] Step 1: Weigh 0.0125g of magnetic graphene oxide nano-demulsifier and add it to 40.0g of aged oil containing polymer;

[0141] Step 2: At 80℃, the magnetic reduced graphene oxide nano-demulsifier is thoroughly mixed with the polymer-containing aged oil, and the mixture is allowed to stand for 2 hours to demulsify the polymer-containing aged oil.

[0142] Step 3: The demulsification rate of the demulsifier is obtained by detecting the dehydration rate of the polyaging oil contained in Step 2. The demulsification rate within 0.5 hours is 3.5%.

[0143] Based on the above performance, it can be seen that the magnetic reduced graphene oxide nano-demulsifier described in this patent has extremely high demulsification performance, a wide range of applications, and low cost. Therefore, it can replace existing demulsifiers and has extremely high market prospects.

[0144] The above description is merely a preferred embodiment of the present invention and is not intended to limit the present invention in any other way. Any modifications or equivalent changes made based on the technical essence of the present invention shall still fall within the scope of protection claimed by the present invention.

[0145] It should be understood that the present invention is not limited to what has been described above and shown in the accompanying drawings, and various modifications and changes can be made without departing from its scope. The scope of the invention is limited only by the appended claims.

Claims

1. Use of a magnetic reduced graphene oxide nanodemulsifier, characterized in that, The magnetic reduced graphene oxide nano-demulsifier is used to demulsify the polymer-containing aged oil, which includes asphaltenes and gum-like non-hydrocarbon compounds. The reduced graphene oxide in the magnetic reduced graphene oxide nano-demulsifier interacts with the asphaltenes and gums through electrostatic and π-π stacking interactions, thereby destroying the oil-water interface film of the polymer-containing aged oil and obtaining an aqueous phase and an oil phase. The steps for demulsification are as follows: Step 1: Weigh the magnetic reduced graphene oxide nano-demulsifier and add it to the polymer-containing aged oil; Step 2: Demulsify the aged oil containing polymer according to the bottle test method. After demulsification, let it stand to obtain the oil phase and the water phase. The magnetic reduced graphene oxide nano-demulsifier after demulsification exists in the water phase. The demulsification rate of the demulsifier is obtained by detecting the dehydration rate of the aged oil containing polymer. Step 3: Filter and separate the magnetic reduced graphene oxide nano-demulsifier in the aqueous phase obtained in Step 2, wash it with an organic solvent until the washing liquid is colorless, dry it at a constant temperature and then recover it for later use. Step 4: Using the magnetic reduced graphene oxide nano-demulsifier recovered in Step 3, the polymer-containing aged oil is repeatedly demulsified, and the demulsification rate of the demulsifier is obtained by detecting the dehydration rate of the polymer-containing aged oil. In step 1, the concentration of the magnetic reduced graphene oxide nano-demulsifier in the polymer-containing aged oil is 0.002-0.2 wt%. In step 2, the bottle test method involves adding a demulsifier to the aged oil containing polymer, performing demulsification during the mixing process, and allowing it to stand after thorough mixing to obtain a clear oil-water interface film. In step 2, the initial demulsification rate of the magnetic reduced graphene oxide nano-demulsifier is 90-100%. The demulsification rate of the magnetic reduced graphene oxide nano-demulsifier recovered in step 4, which can be reused 2-5 times, is 85%-100%. The magnetic reduced graphene oxide nano-demulsifier is formed by a redox reaction between soluble iron salt and graphene oxide. The soluble iron salt is oxidized to iron(III) oxide, and the graphene oxide is reduced to reduced graphene oxide, thus forming the magnetic reduced graphene oxide nano-demulsifier. The iron(III) oxide nanoparticles have a particle size of 15-25 nm, and the reduced graphene oxide is in a layered, wrinkled state. The iron(III) oxide is attached to the surface of the reduced graphene oxide or to the layered wrinkles. In X-ray diffraction, the magnetic reduced graphene oxide nano-demulsifier shows characteristic peaks at diffraction angles 2θ of 30.1°±0.02°, 35.5°±0.02°, 43.1°±0.02°, 53.5°±0.02°, 57.0°±0.02°, and 62.6°±0.02°.

2. Use according to claim 1, characterized in that, The preparation method of the magnetic reduced graphene oxide nano-demulsifier includes the following steps: Step 1: Mix graphene oxide with water to prepare a mixed solution. After ultrasonic dispersion, adjust the pH value with an alkaline solution to obtain mixed solution A. Step 2: Mix the soluble iron salt with water to prepare mixed solution B; Step 3: Add the mixed solution B dropwise to the mixed solution A, and stir at the reaction temperature to obtain a mixture C containing crude solid magnetic reduced graphene oxide nano-demulsifier; Step 4: Filter the crude magnetic reduced graphene oxide nano-demulsifier in the mixture C, wash it with solvent, and then dry it in an oven to obtain the finished magnetic reduced graphene oxide nano-demulsifier. Based on the mass of soluble iron salt, the mass ratio of soluble iron salt to graphene oxide in the magnetic reduced graphene oxide nano-demulsifier is (10-500):1; In step 2, the soluble iron salt is one or more of ferrous chloride tetrahydrate, ferrous chloride hexahydrate, and ferrous sulfate. The reaction temperature in step 3 is 25°C.

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