Method for evaluating demulsification performance of cationic aromatic side chain demulsifier

Abstract

The application relates to an evaluation method of demulsification performance of a cationic aromatic side chain demulsifier, which comprises the following steps: S1, synthesizing 4-bromobutyl triethylammonium bromide, 4-bromobutyl benzalkonium bromide and 4-bromobutyl quinoline bromide, and then synthesizing target products triethylamine-poly succinimide, N, N-dimethyl benzylamine-poly succinimide and quinoline-poly succinimide by chemical modification with poly succinimide as a main chain. The evaluation method of demulsification performance of the cationic aromatic side chain demulsifier, the synthesized TEA-PSI, BZK-PSI and QA-PSI demulsifiers can all be high-efficiency demulsification under different pH conditions, especially under acidic conditions (such as pH=2.0), the demulsification effect is particularly remarkable, and in actual application, the demulsification effect can be guaranteed even under harsh conditions, the demulsifier can not only effectively demulsify, but also can inhibit scale formation to a certain extent, so that the equipment corrosion is reduced, the service life of the equipment is prolonged, the production cost is reduced, the demulsifier has good biocompatibility and environmental friendliness.

Description

TECHNICAL FIELD

[0001] The present application relates to the technical field of demulsification performance evaluation, in particular to a method for evaluating the demulsification performance of a cationic aromatic side chain demulsifier. BACKGROUND

[0002] Natural active substances in crude oil mainly include asphaltene, colloid, naphthenic acid, carbonate and solid particles (clay or wax). The presence of these natural active substances and the action of shear force inevitably lead to the generation of a large amount of crude oil emulsion. In recent years, with the development and application of tertiary oil recovery technology, the content of asphaltene and colloid, which are the main factors affecting the stability of emulsion in crude oil, has been increasing. This not only makes the performance of crude oil emulsion more stable, but also causes problems such as equipment corrosion, greatly increasing the cost of production operation. Untreated wastewater can harm human health and the social environment. Therefore, it is an urgent problem to prepare a low-temperature high-efficiency environmentally friendly demulsifier for O / W type emulsion. The current demulsification technology includes physical demulsification, chemical demulsification and biological demulsification. Chemical demulsification technology has the advantages of high efficiency, flexibility, controllability, multifunctionality and economy, and is the most commonly used demulsification method.

[0003] With the development and application of tertiary oil recovery technology, the content of asphaltene and colloid, which are the main factors affecting the stability of emulsion in crude oil, has been increasing. This not only makes the performance of crude oil emulsion more stable, but also causes problems such as equipment corrosion, greatly increasing the cost of production operation. Therefore, the traditional demulsification technology may not be efficient at low temperatures, especially in the demulsification process of oil / water (O / W) type crude oil emulsion. Secondly, untreated or improperly treated emulsion may cause harm to the environment, such as equipment corrosion and environmental pollution. At the same time, the traditional demulsifier may have a high cost and may increase the cost of production operation during the treatment process. Some demulsifiers may only be effective for specific types of emulsion, lack of multifunctionality, and some demulsifiers may not work well under extreme pH values or other environmental conditions. The present application aims to overcome the limitations of the prior art and provide a more effective, more environmentally friendly, cost-effective demulsifier, and a comprehensive evaluation method to ensure that its performance meets the needs of industrial applications. SUMMARY

[0004] In view of the deficiencies of the prior art, the present application provides a method for evaluating the demulsification performance of a cationic aromatic side chain demulsifier, which has the advantages of being more effective, more environmentally friendly, and more cost-effective, and solves the problems that some demulsifiers may only be effective for specific types of emulsion, lack of multifunctionality, and some demulsifiers may not work well under extreme pH values or other environmental conditions.

[0005] To achieve the above-mentioned purpose, the present application provides the following technical solution: a method for evaluating the demulsification performance of a cationic aromatic side chain demulsifier, comprising the following steps:

[0006] S1, synthesis of 4-bromobutyl triethylammonium bromide (TEA-Br), 4-bromobutyl benzalkonium bromide (BZK-Br) and 4-bromobutyl quinolinium bromide (QA-Br), and then synthesis of target products triethylamine-poly succinimide (TEA-PSI), N, N-dimethyl benzylamine-poly succinimide (BZK-PSI) and quinoline-poly succinimide (QA-PSI) by chemical modification with poly succinimide (PSI) as the main chain;

[0007] S2, determining whether the synthesis product contains the expected functional group by using infrared spectrum, and then verifying the structural integrity of the product by using nuclear magnetic resonance hydrogen spectrum;

[0008] S3, evaluating the demulsification ability of different doses of demulsifier sample solution on O / W type crude oil emulsion by using bottle test method, measuring the demulsification efficiency under different pH conditions, and measuring the demulsification efficiency of the demulsifier under different grafting rates;

[0009] S4, calculating the grafting rate of the product under different grafting rates by nuclear magnetic resonance hydrogen spectrum, and calculating the HLB value of the demulsifier based on the grafting rate;

[0010] S5, evaluating the scale inhibition performance of the demulsifier by static scale inhibition test;

[0011] S6, measuring the interfacial tension of the demulsifier at the oil-water interface by using pendant drop method;

[0012] S7, observing the micro-morphology change of the emulsion in the demulsification process by using polarizing microscope;

[0013] The step of chemical modification synthesis in the step S1 is as follows:

[0014] 1) Dissolve PSI in a suitable organic solvent to prepare monomers for grafting;

[0015] 2) Add the dissolved PSI solution into reaction bottles containing 4-bromobutyl triethylammonium bromide (TEA-Br), 4-bromobutyl benzalkonium bromide (BZK-Br) and 4-bromobutyl quinolinium bromide (QA-Br) respectively, and add an appropriate amount of potassium carbonate catalyst to promote the occurrence of grafting reaction;

[0016] 3) After the reaction is completed, add a non-polar solvent such as acetone or diethyl ether to precipitate the product, so that the product is separated out from the solution;

[0017] 4) Filter and collect the precipitate, and then wash it with solvent for several times to remove unreacted monomers and impurities;

[0018] 5) The product is placed in a vacuum drying oven to dry, obtaining the pure target product triethylamine-poly succinimide (TEA-PSI), N, N-dimethyl benzylamine-poly succinimide (BZK-PSI), quinoline-poly succinimide (QA-PSI);

[0019] The step S3 is specifically:

[0020] S31 Select O / W type crude oil emulsion as the experimental object, set different pH value conditions according to needs, configure different concentration of demulsifier solution, and select demulsifier samples with different grafting rates;

[0021] S32 The demulsifier with selected concentration is added to a certain volume of O / W type crude oil emulsion for mixing, the mixture is allowed to stand, and the demulsification process is allowed to occur, and the demulsification effect is recorded;

[0022] S33 The demulsification efficiency is calculated according to the reduction degree of oil content in the water phase, and the demulsification efficiency of the demulsifier with different doses, different pH value conditions and different grafting rates on the emulsion is compared;

[0023] The grafting rate formula of the step S4 is:

[0024] Grafting rate = integral area of proton peak of grafted part / total integral area of all proton peaks in polymer x 100%;

[0025] The calculation formula of the HLB value of the step S4 can be expressed as:

[0026] HLB = ∑ (contribution value of hydrophilic group) - ∑ (contribution value of hydrophobic group) + correction value;

[0027] The specific steps of the step S5 are as follows:

[0028] S51 A solution containing a certain concentration of calcium sulfate (CaSO4) is configured as a source of simulated scale material;

[0029] S52 Different concentrations of demulsifier are added to the above solution to form a series of demulsifier solutions with different doses;

[0030] S53 The above solution is placed in a static condition, i.e. a non-flowing state, to simulate the scale inhibition environment in actual working conditions;

[0031] S54 After a certain period of time, the precipitation of calcium sulfate is observed and recorded, and the scale inhibition performance of the demulsifier is evaluated by comparing the blank control group without adding the demulsifier with the test group with adding the demulsifier;

[0032] S55 The precipitation amount of calcium sulfate is quantitatively analyzed by turbidity measurement or weight method, and then the scale inhibition efficiency is calculated;

[0033] The formula for calculating the interfacial tension in step S6 is:

[0034] Where P is the pressure difference of the oil droplet, and Dmax and Dmin are the maximum and minimum diameters of the oil droplet, respectively.

[0035] Further, the steps for synthesizing 4-bromobutyl triethylammonium bromide (TEA-Br), 4-bromobutyl benzalkonium bromide (BZK-Br), and 4-bromobutyl quinolinium bromide (QA-Br) in step S1 are as follows:

[0036] 1) Prepare raw materials: add 13 milliliters of 1,4-dibromobutane to a double- necked round-bottom flask equipped with a cooling system, and purge the system with nitrogen;

[0037] 2) Add amine compounds: slowly add 3 milliliters of N,N-dimethylbenzylamine to 50 milliliters of acetonitrile;

[0038] 3) Heat the reaction: heat the mixture to 50°C, stir for 16 hours, and then reflux for 1 hour;

[0039] 4) Separate the product: precipitate the product by adding acetone to the reaction mixture, and then freeze-dry.

[0040] Further, in step S2, the infrared spectrum is used to determine whether the synthesized product contains the expected functional groups. Specifically, the infrared spectrum of the synthesized product is compared with known standard spectra, the positions and intensities of the characteristic absorption peaks are observed, the functional groups in the product are identified using the absorption peaks in the infrared spectrum, and the grafting reaction is verified by observing changes in specific absorption peaks in the infrared spectrum.

[0041] Further, in step S2, the infrared spectra of triethylamine-poly succinimide (TEA-PSI), N,N-dimethylbenzylamine-poly succinimide (BZK-PSI), and quinoline-poly succinimide (QA-PSI) are compared with the original PSI spectrum. The appearance of new absorption peaks or changes in the intensity of existing absorption peaks at specific wave numbers indicate that the grafting reaction was successful.

[0042] Further, the structure integrity of the product is verified using the hydrogen nuclear magnetic resonance spectrum, which is as follows:

[0043] 1) For each synthesized product, triethylamine-poly succinimide (TEA-PSI), N,N-dimethylbenzylamine-poly succinimide (BZK-PSI), and quinoline-poly succinimide (QA-PSI), record its 1 H NMR spectrum;

[0044] 2) Observe the 1The H NMR spectrum is compared with a standard spectrum or a theoretically predicted spectrum to identify the characteristic peaks of each main proton;

[0045] 3) Analyze each peak in the spectrum to confirm whether they match the expected structure;

[0046] 4) Compare the spectrum of each product with the theoretical value to confirm whether all expected proton peaks exist and their positions are correct;

[0047] 5) Calculate the grafting rate by nuclear magnetic resonance hydrogen spectrum.

[0048] Compared with the prior art, the technical scheme of the application has the following beneficial effects:

[0049] The evaluation method of the cationic aromatic side chain demulsifier demulsification performance, the synthesized TEA-PSI, BZK-PSI and QA-PSI demulsifiers can demulsify efficiently under different pH conditions, especially under acidic conditions (such as pH = 2.0), the demulsification effect is particularly remarkable, and in actual application, even under harsh conditions, the demulsification effect can be guaranteed, the demulsifier not only can effectively demulsify, but also can inhibit the formation of scale to some extent, thereby reducing equipment corrosion, prolonging equipment service life, reducing production cost, and at the same time, having good biocompatibility and environmental friendliness, can demulsify efficiently at low temperature, avoiding the environmental pollution problem that may be caused by traditional demulsifiers, by adjusting the grafting rate and optimizing the formula, the use amount of the demulsifier can be reduced, thereby reducing the demulsification treatment cost, the demulsifier can maintain good demulsification performance under different pH conditions, is suitable for various working conditions, improves the application range of the demulsifier, the product is characterized by nuclear magnetic resonance hydrogen spectrum and infrared spectrum, etc., to ensure the structural integrity of the synthesized product, simplifies the experimental operation process, the micro-morphology change of the emulsion in the demulsification process is observed by a polarizing microscope, the action mechanism of the demulsifier is revealed, providing a theoretical basis for the design of the demulsifier, through static scale inhibition test, it is found that BZK-PSI performs outstandingly in scale inhibition performance, the benzene ring functional group contained can effectively disperse and stabilize metal ions, reducing the formation of scale, the interfacial tension of the demulsifier at the oil-water interface is significantly reduced, which is helpful to the demulsification process, through a series of experimental methods such as bottle test, static scale inhibition test, hanging drop method, etc., the performance indicators of the demulsifier are quantitatively evaluated, ensuring the effectiveness and reliability of the demulsifier, these beneficial effects collectively improve the practical value of the demulsifier, and make contributions to the environmental protection and economic benefits of the crude oil processing industry. BRIEF DESCRIPTION OF DRAWINGS

[0050] Figure 1 The figure is a structural schematic diagram of the application;

[0051] Figure 2The infrared spectrum of the PSI, TEA-PSI, BZK-PSI and QA-PSI of the present application;

[0052] Figure 3 The nuclear magnetic resonance hydrogen spectrum of the TEA-Br, BZK-Br and QA-Br of the present application;

[0053] Figure 4 The scale inhibition efficiency of the PSI, TEA-PSI, BZK-PSI and QA-PSI of the present application. DETAILED DESCRIPTION

[0054] The technical solutions in the embodiments of the present application will be clearly and completely described below with reference to the drawings in the embodiments of the present application. Obviously, the described embodiments are only part of the embodiments of the present application, rather than all the embodiments. Based on the embodiments in the present application, all other embodiments obtained by those skilled in the art without creative labor fall within the protection scope of the present application.

[0055] Please refer to Figure 1 The evaluation method of the demulsification performance of the cationic aromatic side chain demulsifier in the embodiment includes the following steps:

[0056] S1, 4-bromobutyl triethylammonium bromide (TEA-Br), 4-bromobutyl benzalkonium bromide (BZK-Br) and 4-bromobutyl quinolinium bromide (QA-Br) are synthesized, and then the target products triethylamine-poly succinimide (TEA-PSI), N,N-dimethyl benzylamine-poly succinimide (BZK-PSI) and quinoline-poly succinimide (QA-PSI) are synthesized by chemical modification with poly succinimide (PSI) as the main chain;

[0057] S2, the infrared spectrum is used to determine whether the synthesized product contains the expected functional group, and then the nuclear magnetic resonance hydrogen spectrum is used to verify the structural integrity of the product;

[0058] S3, the bottle test method is used to evaluate the demulsification ability of the demulsifier sample solution with different dosages on the O / W type crude oil emulsion, to measure the demulsification efficiency under different pH conditions and to measure the demulsification efficiency of the demulsifier under different grafting rates;

[0059] S4, the grafting rate of the product under different grafting rates is calculated by nuclear magnetic resonance hydrogen spectrum, and the HLB value of the demulsifier is calculated based on the grafting rate;

[0060] S5, the static scale inhibition test is used to evaluate the scale inhibition performance of the demulsifier;

[0061] S6, the pendant drop method is used to measure the interfacial tension of the demulsifier at the oil-water interface;

[0062] S7. Observe the micro-morphology changes of the emulsion during the demulsification process by polarizing microscope.

[0063] Wherein, the steps of synthesizing 4-bromobutyl triethylammonium bromide (TEA-Br), 4-bromobutyl benzalkonium bromide (BZK-Br) and 4-bromobutyl quinolinium bromide (QA-Br) in step S1 are as follows:

[0064] 1) Prepare raw materials: add 13 milliliters of 1,4-dibromobutane into a double- necked round-bottom flask with cooling system, and purify the system with nitrogen;

[0065] 2) Add amine compounds: slowly add 3 milliliters of N,N-dimethylbenzylamine into 50 milliliters of acetonitrile;

[0066] 3) Heat the reaction: heat the mixture to 50°C, stir for 16 hours, and then reflux for 1 hour;

[0067] 4) Separate the product: precipitate the product by adding acetone into the reaction mixture, and then freeze-dry.

[0068] Wherein, the steps of chemical modification synthesis in step S1 are as follows:

[0069] 1) Dissolve PSI in a suitable organic solvent, and prepare monomers for grafting;

[0070] 2) Add the dissolved PSI solution into reaction bottles containing 4-bromobutyl triethylammonium bromide (TEA-Br), 4-bromobutyl benzalkonium bromide (BZK-Br) and 4-bromobutyl quinolinium bromide (QA-Br) respectively, and add appropriate amount of potassium carbonate catalyst to promote the occurrence of grafting reaction;

[0071] 3) After the reaction is completed, add a non-polar solvent such as acetone or diethyl ether to precipitate the product, so that the product is separated from the solution;

[0072] 4) Filter and collect the precipitate, and then wash it several times with solvent to remove unreacted monomers and impurities;

[0073] 5) Dry the product in a vacuum drying oven to obtain pure target product triethylamine-poly succinimide (TEA-PSI), N,N-dimethylbenzylamine-poly succinimide (BZK-PSI) and quinoline-poly succinimide (QA-PSI).

[0074] Wherein, in S2, the infrared spectrum is used to determine whether the synthesized product contains the expected functional groups, specifically: compare the infrared spectrum of the synthesized product with the known standard spectrum, find the position and intensity of the characteristic absorption peak, use the absorption peak in the infrared spectrum to identify the functional groups in the product, and observe the changes of the specific absorption peak in the infrared spectrum to verify the grafting reaction.

[0075] In step S2, the infrared spectra of triethylamine-polysuccinimide (TEA-PSI), N, N-dimethylbenzylamine-polysuccinimide (BZK-PSI), and quinoline-polysuccinimide (QA-PSI) are compared with the original PSI spectrum. If new absorption peaks appear or the intensity of the original absorption peaks changes at a specific wave number, it indicates that the grafting reaction is successful.

[0076] In step S2, the infrared spectra of triethylamine-polysuccinimide (TEA-PSI), N, N-dimethylbenzylamine-polysuccinimide (BZK-PSI), and quinoline-polysuccinimide (QA-PSI) are compared with the original PSI spectrum. If new absorption peaks appear or the intensity of the original absorption peaks changes at a specific wave number, it indicates that the grafting reaction is successful.

[0077] 1) For each synthesized product, triethylamine-polysuccinimide (TEA-PSI), N, N-dimethylbenzylamine-polysuccinimide (BZK-PSI), and quinoline-polysuccinimide (QA-PSI), record its 1 H NMR spectrum;

[0078] 2) Compare the 1 H NMR spectrum of the product with the standard spectrum or the theoretically predicted spectrum, and identify the characteristic peaks of each major proton;

[0079] 3) Analyze the peaks in the spectrum to confirm whether they match the expected structure;

[0080] 4) Compare the spectrum of each product with the theoretical value to confirm whether all expected proton peaks exist and their positions are correct;

[0081] 5) Calculate the grafting rate through the hydrogen nuclear magnetic resonance spectrum.

[0082] In step S3, the following steps are performed:

[0083] S31 Select O / W type crude oil emulsion as the experimental object, set different pH conditions as needed, configure different concentrations of demulsifier solution, and select demulsifier samples with different grafting rates;

[0084] S32 Add the selected concentration of demulsifier to a certain volume of O / W type crude oil emulsion and mix, let the mixture stand and allow the demulsification process to occur, and record the demulsification effect;

[0085] S33 Calculate the demulsification efficiency according to the degree of reduction of oil content in the water phase, and compare the demulsification efficiency of demulsifiers with different doses, different pH conditions, and different grafting rates.

[0086] In step S4, the grafting rate formula is:

[0087] Grafting rate = integral area of proton peaks in grafted part / total integral area of all proton peaks in polymer x 100%;

[0088] The formula for calculating the HLB value in step S4 can be expressed as:

[0089] HLB = ∑(contribution value of hydrophilic group) - ∑(contribution value of hydrophobic group) + correction value.

[0090] The specific steps in step S5 are as follows:

[0091] S51 A solution containing a certain concentration of calcium sulfate (CaSO4) is configured as a source of simulated scale material;

[0092] S52 Different concentrations of demulsifiers are added to the above solution to form a series of demulsifier solutions with different doses;

[0093] S53 The above solution is placed in a static condition, i.e., a non-flowing state, to simulate the scale inhibition environment in actual working conditions;

[0094] S54 After a certain period of time, the precipitation of calcium sulfate is observed and recorded, and the scale inhibition performance of the demulsifier is evaluated by comparing the blank control group without adding the demulsifier with the test group with the demulsifier added;

[0095] S55 The amount of calcium sulfate precipitate is quantitatively analyzed by turbidity measurement or gravimetric method, and the scale inhibition efficiency is calculated.

[0096] With the increase of the dosage of demulsifier, its scale inhibition performance on calcium sulfate also gradually increases. When the dosage is 5.0 mg / L, the scale inhibition efficiency of the three demulsifiers on calcium sulfate is about 50.0%, among which the scale inhibition efficiency of QA-PSI is the highest, reaching 51.6%, which is 11.1% higher than that of PSI. Further increasing the dosage to 10.0 mg / L, the scale inhibition efficiency of BZK-PSI can increase to about 68.0%, and when the dosage increases to 25.0 mg / L, the scale inhibition efficiency on calcium sulfate is close to about 90.0%, and it remains almost unchanged with the continuous increase of the dosage.

[0097] The formula for calculating the interfacial tension in step S6 is:

[0098] Where P is the pressure difference of the oil droplets, and Dmax and Dmin are the maximum and minimum diameters of the oil droplets, respectively.

[0099] It should be noted that the pH value: under different pH conditions, the interfacial tension will be different. Experimental results show that when pH = 2.0, the value of interfacial tension decreases the most, which may be due to the fact that under acidic conditions, the oil / water interface film surface in the emulsion usually carries a negative charge, and the cationic demulsifier can better interact with the negatively charged interface film, thereby better dispersing and separating the emulsion.

[0100] Grafting rate: The grafting rate also affects the interfacial tension. Under neutral conditions, the interfacial tension of TEA-PSI, BZK-PSI and QA-PSI demulsifiers decreased to 39.51, 37.12 and 40.10 mN / m, respectively; while at pH = 2.0, the interfacial tension values decreased more, to 37.90, 36.51 and 38.73 mN / m, respectively. This shows that with the increase of grafting rate, the interfacial activity of the demulsifier is enhanced.

[0101] Result analysis

[0102] Interfacial tension reduction: With the increase of the dosage, the interfacial tension of the three demulsifiers gradually decreases, which shows that the demulsifier can effectively reduce the interfacial tension of oil-water interface, which is conducive to the demulsification process.

[0103] Demulsifier performance: Under different pH conditions, BZK-PSI performs better in reducing interfacial tension, which may be due to its containing more benzene rings, having stronger hydrophobicity and dispersibility, and being able to quickly migrate to the oil-water interface and interact with it.

[0104] The above-mentioned embodiments have the following beneficial effects: The TEA-PSI, BZK-PSI and QA-PSI demulsifiers synthesized in the present application can efficiently demulsify under different pH conditions, especially under acidic conditions (such as pH = 2.0), the demulsification effect is particularly significant, and in actual application, the demulsification effect can be guaranteed even under harsh conditions, the demulsifier not only can effectively demulsify, but also can inhibit scale formation to some extent, thereby reducing equipment corrosion, prolonging equipment service life, reducing production cost, and at the same time having good biocompatibility and environmental friendliness, can efficiently demulsify at low temperature, avoiding the environmental pollution problem that may be caused by traditional demulsifiers, by adjusting the grafting rate and optimizing the formula, the dosage of the demulsifier can be reduced, thereby reducing the demulsification treatment cost, the demulsifier can maintain good demulsification performance under different pH conditions, is suitable for various working conditions, improves the application range of the demulsifier, the product is characterized by nuclear magnetic resonance hydrogen spectrum and infrared spectrum, etc., to ensure the structural integrity of the synthesized product, simplifies the experimental operation process, the micro-morphology change of the emulsion in the demulsification process is observed by polarizing microscope, which reveals the mechanism of the demulsifier and provides a theoretical basis for the design of the demulsifier, through static scale inhibition test, it is found that BZK-PSI performs outstanding in scale inhibition performance, the benzene ring functional group contained can effectively disperse and stabilize metal ions, reduce scale formation, the interfacial tension of the demulsifier at the oil-water interface is significantly reduced, which is helpful for the demulsification process, through a series of experimental methods such as bottle test, static scale inhibition test, pendant drop method, etc., the performance indicators of the demulsifier are quantitatively evaluated to ensure the effectiveness and reliability of the demulsifier, these beneficial effects collectively improve the practical value of the demulsifier, and make contributions to the environmental protection and economic benefits of the crude oil processing industry.

[0105] It has to be noted that, in the present document, the terms "first", "second", etc. merely serve to identify a subject or action, without necessarily requiring or implying any such actual relationship or order between such subjects or actions. Moreover, the terms "comprises", "comprising", or any other variation thereof, are intended to cover a non-exclusive inclusion, such that a process, method, article, or apparatus that comprises a list of elements does not include only those elements but can include other elements not expressly listed or inherent to such process, method, article, or apparatus. An element proceeded by "comprises... a" does not, without more constraints, exclude the presence of additional identical elements in the process, method, article, or apparatus that comprises the element.

[0106] While embodiments of the application have been shown and described, it is to be understood that the application is not limited to the details of the embodiments described, since numerous further modifications and changes can be apparent to one skilled in the art without departing from the spirit and scope of the application, which is defined by the appended claims and their equivalents.

Claims

1. A method for evaluating the demulsification performance of a cationic aromatic side chain demulsifier, characterized in that: The method comprises the following steps: S1, synthesizing 4-bromobutyl triethylammonium bromide (TEA-Br), 4-bromobutyl benzalkonium bromide (BZK-Br) and 4-bromobutyl quinolinium bromide (QA-Br), and then synthesizing target products triethylamine-poly succinimide (TEA-PSI), N,N-dimethyl benzylamine-poly succinimide (BZK-PSI) and quinoline-poly succinimide (QA-PSI) by chemical modification with poly succinimide (PSI) as a main chain; S2, determining whether the synthesized product contains expected functional groups by using an infrared spectrum, and then verifying the structural integrity of the product by using a hydrogen nuclear magnetic resonance spectrum; S3, evaluating the demulsification ability of demulsifier samples of different dosages on O / W type crude oil emulsions by using a bottle test method, measuring the demulsification efficiency under different pH conditions and measuring the demulsification efficiency of the demulsifier under different grafting rates; S4, calculating the grafting rate of the product under different grafting rates by using a hydrogen nuclear magnetic resonance spectrum, and calculating the HLB value of the demulsifier based on the grafting rate; S5, evaluating the scale inhibition performance of the demulsifier by using a static scale inhibition test; S6, measuring the interfacial tension of the demulsifier at an oil-water interface by using a pendant drop method; S7, observing the micro-morphology change of the emulsion in the demulsification process by using a polarizing microscope; The step S1 of chemical modification and synthesis is as follows: 1) dissolving PSI in a suitable organic solvent, and preparing monomers for grafting; 2) adding the dissolved PSI solution into reaction bottles containing 4-bromobutyl triethylammonium bromide (TEA-Br), 4-bromobutyl benzalkonium bromide (BZK-Br) and 4-bromobutyl quinolinium bromide (QA-Br), and adding an appropriate amount of potassium carbonate catalyst to promote the occurrence of the grafting reaction; 3) after the reaction is completed, adding a non-polar solvent such as acetone or diethyl ether to precipitate the product, so that the product is separated out from the solution; 4) filtering and collecting the precipitate, and then washing the precipitate with a solvent for several times to remove unreacted monomers and impurities; 5) drying the product in a vacuum drying box to obtain pure target products triethylamine-poly succinimide (TEA-PSI), N,N-dimethyl benzylamine-poly succinimide (BZK-PSI) and quinoline-poly succinimide (QA-PSI); The step S3 is specifically as follows: S31, selecting O / W type crude oil emulsion as an experimental object, preparing demulsifier solutions of different concentrations according to needs, and selecting demulsifier samples of different grafting rates; S32, adding the demulsifier of the selected concentration into a certain volume of O / W type crude oil emulsion for mixing, allowing the mixture to stand and allowing the demulsification process to occur, and recording the demulsification effect; S33, calculating the demulsification efficiency according to the reduction degree of the oil content in the water phase, and comparing the demulsification efficiency of the demulsifier under different dosages, different pH conditions and different grafting rates; The grafting rate formula of the step S4 is as follows: Grafting rate = integral area of proton peaks of grafted part / total integral area of all proton peaks in polymer × 100%; The calculation formula of the HLB value of the step S4 can be expressed as follows: HLB = ∑(contribution value of hydrophilic group) - ∑(contribution value of hydrophobic group) + correction value; The step S5 is specifically as follows: S51: prepare a solution containing a certain concentration of calcium sulfate (CaSO4) as a source of simulated scale material; S52: add different concentrations of demulsifiers to the above solution to form a series of demulsifier solutions with different dosages; S53: place the above solution in a static condition, i.e., a non-flowing state, to simulate the scale inhibition environment in actual working conditions; S54: after a certain period of time, observe and record the precipitation of calcium sulfate, and evaluate the scale inhibition performance of the demulsifier by comparing the blank control group without adding the demulsifier with the test group with the demulsifier added; S55: quantitatively analyze the amount of calcium sulfate precipitated by turbidity measurement or gravimetric method, and then calculate the scale inhibition efficiency; The formula for calculating the interfacial tension in step S6 is: where P is the pressure difference of the oil droplets, Dmax and Dmin are the maximum and minimum diameters of the oil droplets, respectively.

2. The method for evaluating the demulsification performance of a cationic aromatic side chain demulsifier according to claim 1, characterized in that: In step S2, the infrared spectrum is used to determine whether the synthesized product contains the expected functional groups. Specifically, the infrared spectrum of the synthesized product is compared with the known standard spectrum, the positions and intensities of the characteristic absorption peaks are found, the functional groups in the product are identified using the absorption peaks in the infrared spectrum, and the changes in the specific absorption peaks in the infrared spectrum are observed to verify the grafting reaction.

3. The method for evaluating the demulsification performance of a cationic aromatic side chain demulsifier according to claim 1, characterized in that: In step S2, the infrared spectra of triethylamine-poly succinimide (TEA-PSI), N, N-dimethylbenzylamine-poly succinimide (BZK-PSI), and quinoline-poly succinimide (QA-PSI) are compared with the spectrum of the original PSI. The appearance of new absorption peaks or changes in the intensity of the original absorption peaks at specific wave numbers indicates that the grafting reaction is successful.

4. The method for evaluating the demulsification performance of a cationic aromatic side chain demulsifier according to claim 1, characterized in that: The structure integrity of the product is verified by nuclear magnetic resonance hydrogen spectrum as follows: 1) For each synthetic product Triethylamine-poly succinimide (TEA-PSI), N,N- dimethylbenzylamine-poly succinimide (BZK-PSI), Quinoline-poly succinimide (QA-PSI), record its 1 H NMR spectra; 2) the product is 1 HNMR spectra were compared to standard spectra or theoretical predicted spectra to identify the characteristic peaks of each major proton; 3) analyze the peaks in the spectrum to confirm whether they match the expected structure; 4) compare the spectrum of each product with the theoretical value to confirm whether all expected proton peaks exist and whether their positions are correct; 5) calculate the grafting rate by nuclear magnetic resonance hydrogen spectrum.

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