Modified biomass-based demulsifier and preparation method and application thereof

Abstract

This invention discloses a modified biomass-based demulsifier, its preparation method, and its application, belonging to the field of oil-water emulsion treatment technology. The preparation method of the modified biomass-based demulsifier includes the following steps: S1, soaking biomass in alcohol, followed by drying and pulverizing to obtain pretreated biomass; S2, mixing the pretreated biomass, activator, and solvent at 65-95°C with stirring, then adding bromoalkane and a phase transfer catalyst and continuing the alkylation reaction at 65-95°C to obtain the modified biomass-based demulsifier. Furthermore, this invention also proposes a modified biomass-based demulsifier prepared by the above method. In addition, this invention proposes the application of the above modified biomass-based demulsifier in crude oil emulsion demulsification. The modified biomass-based demulsifier proposed in this invention exhibits excellent demulsification efficiency.

Description

Technical Field

[0001] This invention relates to the field of oil-water emulsion treatment technology, specifically to a modified biomass-based demulsifier, its preparation method, and its application. Background Technology

[0002] With the continuous expansion of industry and the economy, global demand for oil is constantly rising. Intensive extraction has led to a decline in the reservoir energy of most oil fields, rendering conventional oil recovery methods insufficient to meet production targets. Enhanced oil recovery technologies such as waterflooding and chemical flooding are gradually being applied to alleviate supply and demand pressures. However, these technologies often produce large amounts of stable water-in-oil (OI) emulsions, which are difficult to separate effectively through natural sedimentation. Asphaltenes, resins, and other natural surfactants in crude oil are key factors in maintaining emulsion stability. These components assemble into a dense viscoelastic interfacial film at the OII through non-covalent interactions (including π-π stacking, hydrogen bonding, and van der Waals forces), thereby inhibiting the coalescence of dispersed droplets. Untreated oil-water emulsions pose significant risks, including increased gathering and transportation pressure, accelerated equipment corrosion, and adverse effects on downstream refining processes. Therefore, effective demulsification methods are needed to eliminate these hazards and achieve sustainable water circulation and crude oil extraction.

[0003] Currently, the treatment of oil-water emulsions at oilfield joint stations can be divided into two stages: chemical demulsifier destabilization and physical enhanced separation. Chemical demulsification, as a key step in crude oil dehydration, is a crucial technology for disrupting the OWI (oil-water interface) film. The most widely used demulsifiers in oilfields are block polyether demulsifiers based on ethylene oxide (EO) and propylene oxide (PO). A proper balance between EO and PO units and suitable chain lengths allow demulsifier molecules to adsorb at the OWI. Leveraging their competitive adsorption advantage at the OWI, they replace natural surfactants such as asphaltenes, thus forming an unstable composite interfacial film. Although block polyether demulsifiers have many advantages, their raw materials are heavily dependent on petroleum resources, their preparation processes are complex, and they carry high risks. In contrast, demulsifiers derived from natural biomass have become very promising research candidates due to their renewability, environmental friendliness, and economic feasibility.

[0004] Compared to raw materials such as cellulose, starch, and sucrose, which require purification, agricultural waste such as rice husks exhibits significant advantages in terms of sustainability and cost-effectiveness. Therefore, how to utilize the abundant hydroxyl reaction sites on the surface of biomass such as rice husks to achieve efficient hydrophobic modification through a simple, safe, one-step reaction, and prepare a highly efficient biomass-based demulsifier, is a technical problem that needs to be solved in the current technology. Summary of the Invention

[0005] The purpose of this invention is to overcome the above-mentioned technical deficiencies and provide a modified biomass-based demulsifier, its preparation method and application, solving the technical problem of how to utilize the abundant hydroxyl reaction sites on the surface of biomass such as rice husks to achieve efficient hydrophobic modification through a simple and safe one-step reaction, and to prepare a highly efficient biomass-based demulsifier.

[0006] To achieve the above-mentioned technical objectives, the present invention provides a method for preparing a modified biomass-based demulsifier, comprising the following steps: S1. Soak biomass in alcohol, then dry and pulverize it to obtain pretreated biomass; S2. The pretreated biomass, activator and solvent are mixed and stirred at 65-95°C, and then bromoalkane and phase transfer catalyst are added to continue the alkylation reaction at 65-95°C to obtain the modified biomass-based demulsifier.

[0007] In any embodiment, in step S1, the volume concentration of the alcohol is 95%-99%.

[0008] In any embodiment, in step S1, after pulverization, the pretreated biomass powder is obtained by passing it through a 160-250 mesh sieve; and / or, the biomass is rice husk.

[0009] In any embodiment, in step S2, the bromoalkane is one or both of 1-bromohexadecane and 1-bromooctadecane.

[0010] In any embodiment, in step S2, the solvent is one or more of N,N-dimethylformamide, N,N-dimethylacetamide, dimethyl sulfoxide, N-methylpyrrolidone, and xylene.

[0011] In any embodiment, in step S2, the activator is one or more of sodium hydroxide, potassium hydroxide, and sodium hydride.

[0012] In any embodiment, in step S2, the phase transfer catalyst is one or more of tetrabutylammonium bromide, tetrabutylammonium chloride, and benzyltriethylammonium chloride.

[0013] In any embodiment, in step S2, the amount of bromoalkane added is 50%-200% of the mass of the pretreated biomass powder; and / or, in step S2, the alkylation reaction time is 12-24 h; and / or, the mass ratio of the pretreated biomass powder to the bromoalkane is 1:(1.5-2); and / or, the mass ratio of the pretreated biomass powder to the phase transfer catalyst is 1:(0.05-0.1).

[0014] In addition, the present invention also proposes a modified biomass-based demulsifier, which is prepared by the above preparation method.

[0015] Furthermore, this invention also proposes the application of the modified biomass-based demulsifier prepared by the above preparation method or the above modified biomass-based demulsifier in crude oil emulsion demulsification.

[0016] Compared with existing technologies, the beneficial effects of this invention include: the demulsifier prepared by this invention uses abundant agricultural waste such as rice husks directly as the hydrophilic reaction center, and grafts hydrophobic segments through a one-step alkylation reaction. The suitable amphiphilic hydrophilic center, rich in oxygen, provides dense hydrogen bond sites, while the long hydrophobic chain provides steric hindrance. This synergistic effect can effectively break the stable interfacial film formed by asphaltene. Furthermore, compared with commercial demulsifiers that have disadvantages such as high raw material costs, high synthesis risks, and high environmental pollution risks, alkylated rice husk demulsifiers have significant advantages such as low raw material costs, environmental friendliness, low preparation temperature, and simple and safe processing. Through a simple one-step modification, efficient surface modification of the rice husk surface is achieved, demonstrating good application potential and excellent demulsification efficiency.

[0017] This invention directly utilizes rice husk powder in situ, which not only avoids complex purification procedures and dangerous preparation processes, but also utilizes its inherent interfacial active components (such as SiO2) to synergistically enhance oil-water separation performance. Attached Figure Description

[0018] Figure 1 This is the infrared spectrum of the alkylated hydrophobic modified rice husk demulsifier prepared in Example 4 of this invention. Detailed Implementation

[0019] The "range" disclosed in this application is defined by a lower limit and an upper limit. A given range is defined by selecting a lower limit and an upper limit, which define the boundaries of a particular range. Ranges defined in this way can include or exclude endpoints and can be arbitrarily combined; that is, any lower limit can be combined with any upper limit to form a range. For example, if ranges of 60~120 and 80~110 are listed for a specific parameter, it is also expected that ranges of 60~110 and 80~120 are also included. Furthermore, if minimum range values ​​of 1 and 2 are listed, and if maximum range values ​​of 3, 4, and 5 are listed, then the following ranges are all expected: 1~3, 1~4, 1~5, 2~3, 2~4, and 2~5. In this application, unless otherwise stated, the numerical range "a~b" represents a shortened representation of any combination of real numbers between a and b, where a and b are real numbers. For example, the numerical range "0~5" indicates that all real numbers between "0~5" have been listed in this article; "0~5" is simply a shortened representation of these numerical combinations. Furthermore, when a parameter is stated as an integer ≥2, it is equivalent to disclosing that the parameter is, for example, an integer such as 2, 3, 4, 5, 6, 7, 8, 9, 10, 11, 12, etc.

[0020] Unless otherwise specified, the terms "comprising" and "including" as used in this application can be open-ended or closed-ended. For example, "comprising" and "including" can mean that other components not listed may also be included, or that only the listed components may be included.

[0021] Unless otherwise specified, the term "or" is inclusive in this application. For example, the phrase "A or B" means "A, B, or both A and B". More specifically, the condition "A or B" is satisfied by any of the following conditions: A is true (or exists) and B is false (or does not exist); A is false (or does not exist) and B is true (or exists); or both A and B are true (or exist).

[0022] This specific embodiment provides a method for preparing a modified biomass-based demulsifier, comprising the following steps: S1. The biomass is soaked in alcohol, then dried and pulverized, and then passed through a 160-250 mesh sieve to obtain pretreated biomass; the volume concentration of the alcohol is 95%-99%; the biomass is preferably rice husk; S2. The pretreated biomass, activator, and solvent are mixed and stirred at 65-95°C. Then, bromoalkane and phase transfer catalyst are added, and the alkylation reaction is continued at 65-95°C to obtain a modified biomass-based demulsifier. The bromoalkane is one or both of 1-bromohexadecane (C16Br) and 1-bromooctadecane (C18Br). The solvent is one of N,N-dimethylformamide (DMF), N,N-dimethylacetamide (DMA), dimethyl sulfoxide (DMSO), N-methylpyrrolidone (NMP), and xylene (DMB). Or multiple; the activator is one or more of sodium hydroxide, potassium hydroxide and sodium hydride; the phase transfer catalyst is one or more of tetrabutylammonium bromide (TBAB), tetrabutylammonium chloride (TBAC) and benzyltriethylammonium chloride (TEBAC); the amount of bromoalkane added is 50%-200% of the mass of the pretreated biomass powder; the mass ratio of the pretreated biomass powder to the bromoalkane is 1:(1.5-2); the mass ratio of the pretreated biomass powder to the phase transfer catalyst is 1:(0.05-0.1).

[0023] The relevant reaction formulas are as follows:

[0024] This specific embodiment also proposes a modified biomass-based demulsifier, which is prepared by the above preparation method.

[0025] This specific embodiment also proposes the application of the modified biomass-based demulsifier prepared by the above preparation method or the above modified biomass-based demulsifier in crude oil emulsion demulsification, including the following steps: dispersing the demulsifier in a solvent, and then mixing it with the crude oil emulsion for demulsification; the solvent is at least one of methanol or ethanol, the mass ratio of water to crude oil in the preparation of the crude oil emulsion is 7:3, and the crude oil emulsion is a water-in-oil (W / O) type crude oil emulsion.

[0026] To make the objectives, technical solutions, and advantages of this invention clearer, the invention will be further described in detail below with reference to the accompanying drawings and embodiments. It should be understood that the specific embodiments described herein are merely illustrative and not intended to limit the invention.

[0027] In this invention, the terms "some embodiments," "this embodiment," and examples are used to describe a subset of all possible embodiments. However, it is understood that "some embodiments" can be the same subset or different subsets of all possible embodiments and can be combined with each other without conflict.

[0028] If the application documents contain similar descriptions such as "first / second", the following explanation shall be added: In the following description, the terms "first / second / third" are used only to distinguish similar objects and do not represent a specific ordering of objects. It is understood that "first / second / third" may be interchanged in a specific order or sequence where permitted, so that the embodiments described herein can be implemented in an order other than that illustrated or described herein.

[0029] In this embodiment, the term "and / or" is merely a description of the relationship between related objects, indicating that there can be three relationships. For example, object A and / or object B can represent three situations: object A exists alone, object A and object B exist simultaneously, and object B exists alone.

[0030] The following describes embodiments of this application. The embodiments described below are exemplary and are only used to explain this application, and should not be construed as limiting this application. Where specific techniques or conditions are not specified in the embodiments, they are performed according to the techniques or conditions described in the literature in this field or according to the product instructions. Reagents or instruments used, unless otherwise specified, are all conventional products that can be obtained commercially.

[0031] Example 1

[0032] This embodiment proposes an alkylated hydrophobic modified rice husk-based demulsifier, which is obtained through the following steps: S1. Rice husks are soaked in industrial alcohol, then dried and pulverized, and then passed through a 200-mesh sieve to obtain pretreated rice husks (i.e., RHP); the volume concentration of the industrial alcohol is 99%. S2. Place 1.0 g RHP and 0.2 g NaOH in a three-necked flask, and add 10 mL DMF as a solvent. Heat the mixture to 85 °C and stir for 1 hour to allow swelling. Subsequently, add 1.0 g C18Br and 0.05 g TBAB (as a phase transfer catalyst) at 85 °C, and allow the reaction to proceed with continuous stirring at 85 °C for 24 hours. After the reaction, collect the solid product by vacuum filtration and wash with ethanol to remove residual solvent and reactants. Dry the obtained product at 70 °C for 12 hours to obtain the modified rice husk-based demulsifier.

[0033] Example 2

[0034] This embodiment proposes an alkylated hydrophobic modified rice husk-based demulsifier, which is obtained through the following steps: S1. Rice husks are soaked in industrial alcohol, then dried and pulverized, and then passed through a 160-mesh sieve to obtain pretreated rice husks (i.e., RHP); the volume concentration of the industrial alcohol is 99%. S2. Place 1.0 g RHP and 0.2 g NaOH in a three-necked flask, and add 11 mL DMF as a solvent. Heat the mixture to 65 °C and stir for 1 hour to allow swelling. Subsequently, add 1.25 g C18Br and 0.06 g TBAB (as a phase transfer catalyst) at 65 °C, and allow the reaction to proceed with continuous stirring at 65 °C for 24 hours. After the reaction, collect the solid product by vacuum filtration and wash with ethanol to remove residual solvent and reactants. Dry the obtained product at 70 °C for 12 hours to obtain the modified rice husk-based demulsifier.

[0035] Example 3

[0036] This embodiment proposes an alkylated hydrophobic modified rice husk-based demulsifier, which is obtained through the following steps: S1. Rice husks are soaked in industrial alcohol, then dried and pulverized, and then passed through a 250-mesh sieve to obtain pretreated rice husks (i.e., RHP); the volume concentration of the industrial alcohol is 99%. S2. Place 1.0 g RHP and 0.2 g NaOH in a three-necked flask, and add 13 mL DMF as a solvent. Heat the mixture to 95 °C and stir for 1 hour to allow swelling. Subsequently, add 1.5 g C18Br and 0.07 g TBAB (as a phase transfer catalyst) at 95 °C, and allow the reaction to proceed for 12 hours with continuous stirring at 95 °C. After the reaction, collect the solid product by vacuum filtration and wash with ethanol to remove residual solvent and reactants. Dry the obtained product at 70 °C for 12 hours to obtain the modified rice husk-based demulsifier.

[0037] Example 4

[0038] This embodiment proposes an alkylated hydrophobic modified rice husk-based demulsifier, which is obtained through the following steps: S1. Rice husks are soaked in industrial alcohol, then dried and pulverized, and then passed through a 250-mesh sieve to obtain pretreated rice husks (i.e., RHP); the volume concentration of the industrial alcohol is 99%. S2. Place 1.0 g RHP and 0.2 g NaOH in a three-necked flask, and add 14 mL DMF as a solvent. Heat the mixture to 85 °C and stir for 1 hour to allow swelling. Subsequently, add 1.75 g C18Br and 0.085 g TBAB (as a phase transfer catalyst) at 85 °C, and allow the reaction to proceed at 85 °C with continuous stirring for 24 hours. After the reaction, collect the solid product by vacuum filtration and wash with ethanol to remove residual solvent and reactants. Dry the resulting product at 70 °C for 12 hours to obtain the modified rice husk-based demulsifier.

[0039] Figure 1The FT-IR spectra of rice husk powder and modified rice husk powder are shown. At approximately 3400 cm⁻¹... -1 The broad absorption peak observed at 2910 cm⁻¹ can be attributed to the OH stretching vibrations in cellulose, hemicellulose, and lignin on the surface of rice husk powder. For the RHPB sample, the peak at 2910 cm⁻¹ is also significant. -1 and 2844 cm -1 A distinct symmetric and asymmetric stretching vibration peak of the -CH2- group appeared at approximately 1473 cm⁻¹. -1 A strong CH bending vibration peak was observed at 718 cm⁻¹. Furthermore, a strong CH bending vibration peak was observed at 718 cm⁻¹. -1 The absorption band at this point corresponds to the chain segment vibration of -(CH2)n- in the long alkyl chain, indicating the presence of -(CH2)n- structural units (n ≥ 4). At 1000-1100 cm⁻¹ -1 The signals within the range are attributed to overlapping COC and CO bonds in the cellulose and hemicellulose backbone, a typical characteristic of biomass polysaccharides. These changes confirm that C18Br (octadecane bromide) has been successfully grafted onto the surface of rice husk powder, achieving alkylation modification of the rice husk powder.

[0040] Example 5

[0041] This embodiment proposes an alkylated hydrophobic modified rice husk-based demulsifier, which is obtained through the following steps: S1. Rice husks are soaked in industrial alcohol, then dried and pulverized, and then passed through a 250-mesh sieve to obtain pretreated rice husks (i.e., RHP); the volume concentration of the industrial alcohol is 99%. S2. Place 1.0 g RHP and 0.2 g NaOH in a three-necked flask, and add 20 mL DMF as a solvent. Heat the mixture to 85 °C and stir for 1 hour to allow swelling. Subsequently, add 2.0 g C18Br and 0.097 g TBAB (as a phase transfer catalyst) at 85 °C, and allow the reaction to proceed at 85 °C with continuous stirring for 24 hours. After the reaction, collect the solid product by vacuum filtration and wash with ethanol to remove residual solvent and reactants. Dry the obtained product at 70 °C for 12 hours to obtain the modified rice husk-based demulsifier.

[0042] Example 6

[0043] This embodiment proposes an alkylated hydrophobic modified rice husk-based demulsifier, which is obtained through the following steps: Rice husks were soaked in industrial alcohol, then dried and pulverized, and finally passed through a 250-mesh sieve to obtain pretreated rice husks (i.e., RHP); the volume concentration of the industrial alcohol was 99%. 1.0 g RHP and 0.2 g NaOH were placed in a three-necked flask, and 14 mL DMF was added as a solvent. The mixture was heated to 85 °C and stirred for 1 hour to allow swelling. Subsequently, 1.75 g C16Br and 0.085 g TBAB (as a phase transfer catalyst) were added at 85 °C, and the reaction was carried out with continuous stirring at 85 °C for 24 hours. After the reaction, the solid product was collected by vacuum filtration and washed with ethanol to remove residual solvent and reactants. The resulting product was dried at 70 °C for 12 hours to obtain the modified rice husk-based demulsifier.

[0044] Comparative Example 1 This comparative example presents an alkylated hydrophobic modified rice husk-based demulsifier, which is obtained through the following steps: Rice husks were soaked in industrial alcohol, then dried and pulverized, and finally passed through a 250-mesh sieve to obtain pretreated rice husks (i.e., RHP); the volume concentration of the industrial alcohol was 99%. 1.0 g RHP and 0.2 g NaOH were placed in a three-necked flask, and 14 mL DMF was added as a solvent. The mixture was heated to 85 °C and stirred for 1 hour to allow swelling. Subsequently, 1.75 g C12Br and 0.085 g TBAB (as a phase transfer catalyst) were added at 85 °C, and the reaction was carried out with continuous stirring at 85 °C for 24 hours. After the reaction, the solid product was collected by vacuum filtration and washed with ethanol to remove residual solvent and reactants. The resulting product was dried at 70 °C for 12 hours to obtain the modified rice husk-based demulsifier.

[0045] Comparative Example 2 This comparative example presents an alkylated hydrophobic modified rice husk-based demulsifier, which is obtained through the following steps: S1. Rice husks are soaked in industrial alcohol, then dried and pulverized, and then passed through a 250-mesh sieve to obtain pretreated rice husks (i.e., RHP); the volume concentration of the industrial alcohol is 99%. S2. Place 1.0 g RHP and 0.2 g NaOH in a three-necked flask, and add 8 mL DMF as solvent. Heat the mixture to 85 °C and stir for 1 hour to allow swelling. Subsequently, add 0.5 g C18Br and 0.025 g TBAB (as a phase transfer catalyst), and allow the reaction to proceed for 24 hours with continuous stirring. After the reaction, collect the solid product by vacuum filtration and wash with ethanol to remove residual solvent and reactants. Dry the obtained product at 70 °C for 12 hours to obtain the modified rice husk-based demulsifier.

[0046] Comparative Example 3 This comparative example presents an alkylated hydrophobic modified rice husk-based demulsifier, which is obtained through the following steps: S1. Rice husks are soaked in industrial alcohol, then dried and pulverized, and then passed through a 250-mesh sieve to obtain pretreated rice husks (i.e., RHP); the volume concentration of the industrial alcohol is 99%. S2. Place 1.0 g RHP and 0.2 g NaOH in a three-necked flask, and add 9 mL DMF as solvent. Heat the mixture to 85 °C and stir for 1 hour to allow swelling. Subsequently, add 0.75 g C18Br and 0.036 g TBAB (as a phase transfer catalyst), and allow the reaction to proceed for 24 hours with continuous stirring. After the reaction, collect the solid product by vacuum filtration and wash with ethanol to remove residual solvent and reactants. Dry the resulting product at 70 °C for 12 hours to obtain the modified rice husk-based demulsifier.

[0047] Performance testing: A W / O emulsion was prepared using a crude oil to deionized water volume ratio of 3:7. The mixture was first heated in a 70°C water bath for 30 minutes, then sheared at 6000 rpm for 20 minutes using a homogenizer (FJ-200, Shanghai). No phase separation occurred after the resulting emulsion was placed in a 70°C water bath for one week, indicating that the emulsion was very stable.

[0048] The demulsification performance of the demulsifier under different conditions was evaluated using a bottle test method. A predetermined mass of demulsifier was added to 1 g of ethanol and ultrasonically dispersed. Then, 19 mL of emulsion was added, and the bottle was shaken vigorously 100 times. The test bottle was placed in a water bath at a specified temperature to monitor the demulsification process. The effect of salinity on demulsification performance was studied using NaCl to control the salinity. DE was calculated according to equation (1).

[0049]

[0050] In the formula, DE (%) is the demulsification efficiency, H is the height of the separated aqueous phase, H0 is the total height, and K is the water content of the emulsion (70%).

[0051] Test Example 1 Based on the demulsifiers prepared in Examples 1-6 (corresponding to experimental groups 1-6) and Comparative Examples 1-3 (corresponding to control groups 1-3), demulsifier suspensions of the same concentration were prepared. These suspensions were used to characterize the demulsification performance based on different mass ratios of C18Br and different alkyl chain lengths from rice husks. The tests were conducted in crude oil emulsions at 60℃ for 3 hours, with the specific steps as follows: Table 1. Demulsification results of experimental groups 1-6 and control groups 1-3

[0052] Table 1 shows that the demulsification efficiency of the demulsifiers prepared in Examples 1-6 varies depending on the mass fraction of C18Br and the alkyl chain length. Example 4 exhibits the best demulsification efficiency, likely due to the appropriate increase in C18Br, which allows it to be grafted onto the rice husk surface at a more ideal density and in a more suitable manner. Moderate surface chemical regulation results in an optimal amphiphilic structure. Compared to the control group, different alkyl chain lengths (C12, C16, C18) have a significant impact on demulsification performance, indicating that by selecting and constructing appropriate hydrophobic chain lengths, interfacial activity can be effectively adjusted.

[0053] Test Example 2 Based on the demulsifier prepared in Example 4, demulsifier dispersions of different concentrations were prepared to characterize the demulsification performance of different concentrations of demulsifier in crude oil emulsion at 60°C for 3 hours.

[0054] Table 2. Results of demulsification in experimental group 7-13

[0055] As shown in Table 2, the demulsifier provided by the present invention has good demulsification performance, and can achieve a demulsification efficiency of 95.2% at a demulsification concentration of 600 mg / L.

[0056] Test Example 3 Based on the demulsifier prepared in Example 4, experimental groups 14-18 were established sequentially to characterize the demulsifying performance of the demulsifier at different temperatures at 600 mg / L.

[0057] Table 3. Demulsification results of experimental groups 14-18

[0058] As shown in Table 3, the demulsifier provided by the present invention can achieve a demulsification efficiency of 96.3% at 70°C and as high as 98.6% at 80°C.

[0059] Test Example 4 Based on the demulsifier prepared in Example 4, experimental groups 19-24 were established sequentially to compare the demulsifier with commercial demulsifiers. The demulsification temperature was 60°C and the concentration of the demulsifier was 600 mg / L.

[0060] Table 4. Results of demulsification in experimental group 19-24

[0061] Table 4 shows that the rice husk-based demulsifier achieved a demulsification efficiency of 95.2%, while the demulsification efficiency (DE) of SP169 and PDB9392 was only 87.1% and 88.4%, respectively. Furthermore, the rice husk-based demulsifier achieved a demulsification efficiency comparable to PE10100. These results indicate that the preparation of the rice husk-based demulsifier was successful and possesses excellent demulsification efficiency.

[0062] In summary, commercial demulsifiers suffer from drawbacks such as high raw material costs, high synthesis risks, and high environmental pollution risks. In contrast, the rice husk-based demulsifier proposed in this invention offers significant advantages, including low raw material costs, environmental friendliness, low preparation temperature, and simple and safe processing. Through a simple one-step modification, highly efficient surface modification of multi-component RH is achieved, demonstrating excellent application potential.

[0063] The specific embodiments of the present invention described above do not constitute a limitation on the scope of protection of the present invention. Any other corresponding changes and modifications made in accordance with the technical concept of the present invention should be included within the scope of protection of the claims of the present invention.

Claims

1. A method for preparing a modified biomass-based demulsifier, characterized in that, Includes the following steps: S1. Soak biomass in alcohol, then dry and pulverize it to obtain pretreated biomass; S2. The pretreated biomass, activator and solvent are mixed and stirred at 65-95°C, and then bromoalkane and phase transfer catalyst are added to continue the alkylation reaction at 65-95°C to obtain the modified biomass-based demulsifier.

2. The preparation method of the modified biomass-based demulsifier according to claim 1, characterized in that, In step S1, the volume concentration of the alcohol is 95%-99%.

3. The method for preparing the modified biomass-based demulsifier according to claim 1, characterized in that, In step S1, after pulverization, the pretreated biomass powder is obtained by passing it through a 160-250 mesh sieve; and / or, the biomass is rice husk.

4. The method for preparing the modified biomass-based demulsifier according to claim 1, characterized in that, In step S2, the bromoalkane is one or both of 1-bromohexadecane and 1-bromooctadecane.

5. The method for preparing the modified biomass-based demulsifier according to claim 1, characterized in that, In step S2, the solvent is one or more of N,N-dimethylformamide, N,N-dimethylacetamide, dimethyl sulfoxide, N-methylpyrrolidone, and xylene.

6. The method for preparing the modified biomass-based demulsifier according to claim 1, characterized in that, In step S2, the activator is one or more of sodium hydroxide, potassium hydroxide, and sodium hydride.

7. The method for preparing the modified biomass-based demulsifier according to claim 1, characterized in that, In step S2, the phase transfer catalyst is one or more of tetrabutylammonium bromide, tetrabutylammonium chloride, and benzyltriethylammonium chloride.

8. The method for preparing the modified biomass-based demulsifier according to claim 1, characterized in that, In step S2, the amount of bromoalkane added is 50%-200% of the mass of the pretreated biomass powder; and / or, in step S2, the alkylation reaction time is 12-24 h; and / or, the mass ratio of the pretreated biomass powder to the bromoalkane is 1:(1.5-2); and / or, the mass ratio of the pretreated biomass powder to the phase transfer catalyst is 1:(0.05-0.1).

9. A modified biomass-based demulsifier, characterized in that, It is prepared by the preparation method according to any one of claims 1-8.

10. The application of the modified biomass-based demulsifier prepared by the preparation method according to any one of claims 1-8 or the modified biomass-based demulsifier according to claim 9 in the demulsification of crude oil emulsions.

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