Nanometer demulsifier, preparation method and application thereof

Abstract

A kind of nano demulsifier, which is compounded by microemulsion, water and solvent;The solvent is coated by microemulsion;The microemulsion is light yellow aqueous solution with particle size less than 100 nm, pH is 8-9, and interfacial tension is less than 10 ‑3 mN / m.The nano demulsifier is obtained by mixing microemulsion with water, then slowly adding solvent under stirring condition;When used, the nano demulsifier is mixed with oily sludge, heated and stirred to remove oil and water in oily sludge.The nano demulsifier of the present application is adsorbed on the surface of oily sludge particles, which can break the oil-water interface film, penetrate the polymer package, cause the desorption or demulsification of adsorbed oil with high viscosity in oily sludge, and destroy the stability of colloidal particle family to release bound water, with good viscosity reduction, penetration and solubilization effect, and significant effect of removing oil and water in oily sludge, low cost, simple operation and no secondary pollution.

Description

Technical Field

[0001] This invention belongs to the field of oily sludge treatment technology, specifically relating to a nano-demulsifier, its preparation method, and its application. Background Technology

[0002] In petroleum production, the amount of oily sludge generated is constantly increasing. Oily sludge exists in a stable water-in-oil (W / O) emulsion state, which is difficult to dehydrate using commonly used centrifugal separation, resulting in poor quality of recovered oil. Demulsification and viscosity reduction are necessary to improve dehydration and impurity removal rates. Based on the mechanism of emulsion destruction, Bansbash and Wasan believed that an ideal demulsifier should possess the following characteristics: (1) strong surface activity, with surfactants having higher activity than natural emulsifiers, which can quickly and preferentially adsorb onto the oil-water interface, replacing natural emulsifier molecules and reducing the interfacial tension and interfacial film strength of the droplets; (2) good wetting properties, with demulsifier molecules having good wetting ability, which diffuse into the emulsion droplets and penetrate through the protective layer between solids, and are easily adsorbed onto the surface of solid particles, such as asphalt particles, paraffin particles, clay particles, and metal salt particles, reducing their surface energy, changing the surface wetting properties, destroying the structure between particles on the protective layer, and causing the interfacial film to weaken and break; (3) good demulsifiers have a certain solubility in both oil and water phases; (4) the more demulsifier adsorbs at the interface, the better the demulsification effect. The widely accepted demulsification mechanisms are mainly substitution or replacement, reverse action, counterion action, and agglomeration flocculation and dispersion solubilization.

[0003] However, due to its unique state, it is more difficult to break down than crude oil emulsions. There are few types of demulsifiers, classified by molecular weight into low-molecular-weight demulsifiers, high-molecular-weight demulsifiers, ultra-high-molecular-weight demulsifiers, and compound demulsifiers. Among these, compound demulsifiers have wider applicability and better performance. Chemically, they are mainly based on nonionic polyoxyethylene and polyoxypropylene block polymers. Research on new types of demulsifiers has progressed slowly, focusing primarily on modifications of traditional demulsifiers, such as "head modification, bone replacement, bone addition, chain extension, grafting, crosslinking, and compounding." This approach not only results in low efficiency in screening demulsifiers but also unstable performance. Therefore, a new type of demulsifier is urgently needed to demulsify severely emulsified oily sludge. Summary of the Invention

[0004] The purpose of this invention is to provide a nano-demulsifier, its preparation method, and its application. By mixing a self-made microemulsion with a solvent to form a nano-demulsifier, the nano-sized microemulsion is easily adsorbed at the oil-water interface and on the surface of particles. It also has amphiphilic properties and viscosity-reducing, wetting, penetrating, and solubilizing effects, effectively demulsifying oily sludge and thus easily removing oil and water from the sludge.

[0005] The technical solution adopted in this invention is:

[0006] A nano-demulsifier, characterized in that it is composed of a microemulsion, water, and a solvent; the solvent is coated by the microemulsion; the microemulsion is a pale yellow aqueous solution with a particle size of less than 100 nm, a pH of 8-9, and an interfacial tension of less than 10. -3 mN / m.

[0007] Furthermore, the mass ratio of the microemulsion to the solvent is 1 to 5:1.

[0008] Furthermore, the water content is 10–20 wt%.

[0009] Furthermore, the content of the microemulsion is 40–70 wt%.

[0010] Furthermore, the solvent is selected from at least one of ethyl acetate, solvent oil, and petroleum ether.

[0011] Furthermore, the microemulsion is composed of a surfactant, an aqueous phase, and an oil phase in a mass ratio of 1:1 to 3.5:1 to 3.

[0012] Typical microemulsions consist of surfactants, co-surfactants, an aqueous phase, and an oil phase, with a fixed component ratio. The co-surfactant stabilizes the system and increases the hydrophilicity of the oil phase. However, when the ratio of the oil phase to the surfactant changes, the system becomes unstable and separates into layers, thus generally only miscible with water. The microemulsion of this application is an intermediate raw material designed to achieve miscibility with water and solvents. Besides maintaining a certain interfacial tension and a clear, transparent, and homogeneous appearance, it emphasizes excellent wetting, penetration, and solubilizing properties. Therefore, it does not contain co-surfactants (if it contained co-surfactants like conventional microemulsions, the aforementioned properties would be significantly compromised, and it would also lose its miscibility with solvents). Compared to ordinary microemulsions, this raw material is miscible with solvents. This is the difference between this application and ordinary microemulsions. It is precisely this property that allows it to be miscible with water or solvents, achieving excellent deoiling and dehydration effects in oily sludge.

[0013] Furthermore, the surfactant is composed of sodium dodecylbenzenesulfonate, alkylphenol polyoxyethylene ether, and coconut oil fatty acid diethanolamide in a mass ratio of 1-8:1-4:1-4.

[0014] Furthermore, the oil phase is a light white oil.

[0015] A method for preparing a nano-demulsifier involves mixing a prepared microemulsion with water (the water referred to here is the water that makes up the nano-demulsifier, not the aqueous phase in the microemulsion), then slowly adding solvent dropwise at 40–70°C and stirring at 300 r / min, and stirring for another 20–30 min after the addition is complete to obtain the nano-demulsifier.

[0016] An application of a nano-demulsifier in oily sludge is characterized in that the nano-demulsifier is mixed with oily sludge, heated and stirred to remove oil and water from the oily sludge; wherein the temperature is raised to 60°C to 70°C and the stirring time is 30 to 60 minutes; the mass ratio of the oily sludge to the nano-demulsifier is 100 to 200:1.

[0017] The beneficial effects of this invention are:

[0018] In the nano-demulsifier of this invention, the solvent has excellent viscosity-reducing and dissolving effects on oily sludge, while the microemulsion has ultra-low interfacial tension and good wetting, penetration, and solubilizing capabilities. The microemulsion coats the solvent droplets, mediating the adsorption of the solvent on the surface of the oily sludge particles. It can break the oil-sludge-water interface film, enter the micropores, and penetrate the polymer encapsulation, causing the adsorbed oil with high viscosity in the oily sludge to desorb or demulsify, and disrupting the stability of the colloidal particle groups (clusters), releasing bound water.

[0019] The nano-demulsifier exhibits excellent viscosity-reducing, penetration-enhancing, and solubilizing effects, demonstrating a significant ability to remove oil and water from oily sludge. This invention provides a nano-demulsifier for removing oil and water from oily sludge, with low production process requirements, simple operation, low cost, and no secondary pollution. The nano-demulsifier achieves an oil removal rate of 78.96%–90.95% and a water removal rate of 39%–50%, which is higher than the oil and water removal efficiency of traditional methods. Detailed Implementation

[0020] The oily sludge in this embodiment of the application originated from a refinery. After the water in the oily sludge was evaporated and condensed using azeotropic distillation, the water content was calculated from the readings, and the oil content was tested using an infrared oil analyzer. The tested oily sludge had an oil content of 21%, a water content of 63%, and a solids content of 16%.

[0021] Before application, prepare the microemulsion.

[0022] Formula 1: Add 4g of coconut oil fatty alcohol diethanolamide, 5g of sodium dodecylbenzenesulfonate, and 4g of alkylphenol polyoxyethylene ether to 40mL of water, stir to dissolve, then add 20g of light white oil and stir evenly to obtain microemulsion raw material 1. The measured properties are: particle size 76nm, pH 9, and interfacial tension 0.0008mN / m.

[0023] Formula 2: Add 2g of coconut oil fatty alcohol diethanolamide, 8g of sodium dodecylbenzenesulfonate, and 2g of alkylphenol polyoxyethylene ether to 40mL of water, stir to dissolve, then add 15g of light white oil and stir evenly to obtain microemulsion raw material 1. The measured properties are: particle size 89nm, pH 8, and interfacial tension 0.0009mN / m.

[0024] Formula 3: Add 2.5g of coconut oil fatty alcohol diethanolamide, 5g of sodium dodecylbenzenesulfonate, and 5g of alkylphenol polyoxyethylene ether to 40mL of water, stir to dissolve, then add 15g of light white oil and stir evenly to obtain microemulsion raw material 1. The measured properties are: particle size 93nm, pH 9, and interfacial tension 0.0009mN / m.

[0025] After comparison, Formula 1 was found to have the best performance. In the following application, the microemulsion of Formula 1 was used as the raw material to formulate the nano-demulsifier.

[0026] Example 1

[0027] (1) Add 10g of microemulsion to 5mL of water, stir evenly, then add 5g of ethyl acetate and 5g of solvent oil, stir at 40℃ and 300r / min for 25min to obtain nano-demulsifier.

[0028] (2) Add 1% of the nano-demulsifier to the oily sludge;

[0029] (3) Stir at 60℃ for 60 min;

[0030] Microemulsion:solvent = 1:1 mass ratio; oily sludge to nano-demulsifier mass ratio is 100:1.

[0031] After treatment with nano-demulsifier, the remaining oil content was 4.42%, the remaining water content was 38.43%, the oil removal rate was 78.96%, and the water removal rate was 39%.

[0032] Example 2

[0033] (1) Add 15g of microemulsion to 5mL of water, stir evenly, then add 5g of ethyl acetate and 5g of solvent oil, stir at 50℃ and 300r / min for 25min to obtain nano-demulsifier;

[0034] (2) Add 1% of the nano-demulsifier to the oily sludge;

[0035] (3) Stir for 30 minutes under heating at 65℃;

[0036] The mass ratio of microemulsion to solvent is 1.5:1; the mass ratio of oily sludge to nano-demulsifier is 100:1.

[0037] After treatment with nano-demulsifier, the remaining oil content was 3.14%, the remaining water content was 37.17%, the oil removal rate was 85.03%, and the water removal rate was 41%.

[0038] Example 3

[0039] (1) Add 20g of microemulsion to 5mL of water, stir evenly, then add 5g of solvent oil, stir at 60℃ and 300r / min for 20min to obtain nano-demulsifier;

[0040] (2) Add 1% of the nano-demulsifier to the oily sludge;

[0041] (3) Stir at 65℃ for 40 min;

[0042] The mass ratio of microemulsion to solvent is 4:1; the mass ratio of oily sludge to nano-demulsifier is 100:1.

[0043] After treatment with nano-demulsifier, the remaining oil content was 2.36%, the remaining water content was 35.91%, the oil removal rate was 88.76%, and the water removal rate was 43%.

[0044] Example 4

[0045] (1) Add 25g of microemulsion to 5mL of water, stir evenly, then add 5g of petroleum ether and 5g of solvent oil, stir at 55℃ and 300r / min for 30min to obtain nano-demulsifier.

[0046] (2) Add 0.5% of the nano-demulsifier to the oily sludge;

[0047] (3) Stir for 30 minutes under heating at 60℃;

[0048] The mass ratio of microemulsion to solvent is 2.5:1; the mass ratio of oily sludge to nano-demulsifier is 200:1.

[0049] After treatment with nano-demulsifier, the remaining oil content was 2.87%, the remaining water content was 33.39%, the oil removal rate was 86.33%, and the water removal rate was 47%.

[0050] Example 5

[0051] (1) Add 25g of microemulsion to 5mL of water, stir evenly, then add 5g of ethyl acetate and 5g of petroleum ether, stir at 70℃ and 300r / min for 30min to obtain nano-demulsifier.

[0052] (2) Add 0.5% of the nano-demulsifier to the oily sludge;

[0053] (3) Stir for 30 minutes under heating at 60℃;

[0054] The mass ratio of microemulsion to solvent is 2.5:1; the mass ratio of oily sludge to nano-demulsifier is 200:1.

[0055] After treatment with nano-demulsifier, the remaining oil content was 1.9%, the remaining water content was 31.5%, the oil removal rate was 90.95%, and the water removal rate was 50%.

[0056] Example 6

[0057] (1) Add 25g of microemulsion to 5mL of water, stir evenly, then add 5g of ethyl acetate, stir at 55℃ and 300r / min for 30min to obtain nano-demulsifier;

[0058] (2) Add 0.8% of the nano-demulsifier to the oily sludge;

[0059] (3) Stir for 50 min under heating at 60℃;

[0060] The mass ratio of microemulsion to solvent is 5:1; the mass ratio of oily sludge to nano-demulsifier is 125:1.

[0061] After treatment with nano-demulsifier, the remaining oil content was 2.28%, the remaining water content was 32.76%, the oil removal rate was 89.12%, and the water removal rate was 48%.

Claims

1. A nano-demulsifier, characterized in that, It is composed of microemulsion, water, and solvent; the solvent is coated by the microemulsion; the microemulsion is a pale yellow aqueous solution with a particle size of less than 100 nm, a pH of 8-9, and an interfacial tension of less than 10. -3 mN / m; the mass ratio of the microemulsion to the solvent is 1 to 5:1; the microemulsion is composed of surfactant, aqueous phase and oil phase in a mass ratio of 1:1 to 3.5:1 to 3; the surfactant is composed of sodium dodecylbenzenesulfonate, alkylphenol polyoxyethylene ether and coconut oil fatty acid diethanolamide in a mass ratio of 1 to 8:1 to 4:1 to 4.

2. The nano-demulsifier as described in claim 1, characterized in that, The water content is 10–20 wt%.

3. The nano-demulsifier as described in claim 1, characterized in that, The content of the microemulsion is 40-70 wt%.

4. The nano-demulsifier as described in claim 1, characterized in that, The solvent is selected from at least one of ethyl acetate, solvent oil, and petroleum ether.

5. The nano-demulsifier as described in claim 1, characterized in that, The oil phase is light white oil.

6. The method for preparing any one of the nano-demulsifiers as described in claims 1 to 5, characterized in that, The prepared microemulsion was mixed with water, and then the solvent was slowly added dropwise at 40-70°C and 300 r / min with stirring. After the addition was complete, the mixture was stirred for another 20-30 min to obtain the nano-demulsifier.

7. The application of any one of the nano-demulsifiers as described in claims 1 to 5 in oily sludge, characterized in that, The nano-demulsifier is mixed with oily sludge, heated and stirred to remove oil and water from the oily sludge; wherein the temperature is heated to 60℃~70℃ and the stirring time is 30~60min; the mass ratio of the oily sludge to the nano-demulsifier is 100~200:1.