Multi-amino nonionic demulsifier as well as preparation method and application thereof

Abstract

The invention discloses a polyamido nonionic demulsifier as well as a preparation method and application thereof, and belongs to the technical field of oil-water emulsion treatment. The multi-amino nonionic demulsifier comprises one or more of compounds with the following structural formula: # imgabs0 #, R1 and R2 are respectively selected from any one of C8-C12 alkyl groups, and n is any integer from 4 to 6. In addition, the invention also provides a preparation method of the polyamino nonionic demulsifier, which comprises the following steps: taking polyethylene polyamine and alkyl glycidyl ether as raw materials, and carrying out ring-opening reaction in a solvent A to obtain the polyamino nonionic demulsifier. In addition, the specific embodiment of the invention also provides an application of the polyamino nonionic demulsifier or the polyamino nonionic demulsifier prepared by the preparation method in demulsification of a crude oil emulsion. The demulsifier has a good demulsification effect at a relatively low temperature.

Description

Technical Field

[0001] The present invention relates to the technical field of oil-water emulsion treatment, and particularly relates to a polyamine-based non-ionic demulsifier, a preparation method thereof, and an application thereof. Background Art

[0002] During the oil extraction process, a large amount of oil-water emulsion is usually generated. Due to the presence of natural surfactants, the properties of such emulsions are very stable. The natural active substances in crude oil mainly include asphaltenes, resins, naphthenic acids, and solid particles (clay or wax). These natural surfactants usually have amphiphilicity and can spontaneously migrate to the oil-water interface and form a stable protective film, thereby stabilizing the emulsion by preventing the coalescence of water droplets in the crude oil. Usually, emulsions are harmful, and direct discharge will cause environmental pollution and damage the ecosystem. The inorganic salts dissolved in the emulsion will seriously corrode the equipment and reduce the usability of the pipeline. At the same time, the formation of the emulsion will also increase the viscosity of the crude oil, making the transportation and processing of the crude oil more difficult. Therefore, separating the water phase from the crude oil emulsion before transportation and refining is important and crucial. Chemical demulsification is widely used because of its simple operation, low cost, fast demulsification rate, and high demulsification efficiency.

[0003] Chemical demulsification is a method of realizing oil-water separation by adding a demulsifier to the emulsion. When the demulsifier is added to the emulsion, relying on its excellent interfacial activity and amphiphilicity, it will spontaneously migrate to the oil-water interface and replace the natural surfactants such as asphaltenes at the interface to form an unstable composite film. The formation of this composite film will reduce the strength of the interfacial film and thus promote the coalescence of water droplets, ultimately realizing oil-water separation. Chemical demulsifiers mainly include polymeric surfactants, nanoparticles, and ionic liquids, etc. For example, ethylene oxide-propylene oxide (EO-PO) block copolymers, silicone polyethers, dendritic polymers, biodegradable polymeric surfactants, and nanoparticle-based demulsifiers.

[0004] However, these demulsifiers have problems such as complex preparation processes, high raw material costs, poor demulsification performance, and potential environmental pollution risks. Summary of the Invention

[0005] The purpose of the present invention is to overcome the above technical deficiencies, provide a polyamine-based non-ionic demulsifier, a preparation method thereof, and an application thereof, and solve the problems of poor demulsification performance of the demulsifier, high raw material cost of the demulsifier, and poor adaptability in the prior art.

[0006] To achieve the above technical purpose, the technical solution of the present invention provides a polyamine-based non-ionic demulsifier, including one or more of the compounds having the following structural formulas:

[0007]

[0008] Wherein, R1 and R2 are respectively selected from any one of C8-C 12 alkyl, and n is any integer from 4 to 6.

[0009] In any embodiment, R1 and R2 are respectively selected from one of C8-C 12 linear alkyl.

[0010] In any embodiment, R1 and R2 are the same.

[0011] In addition, the present invention also provides a method for preparing the above-mentioned polyamine non-ionic demulsifier, comprising the following steps:

[0012] Using polyalkylene polyamine and alkyl glycidyl ether as raw materials, an ring-opening reaction occurs in solvent A to obtain the polyamine non-ionic demulsifier.

[0013] In any embodiment, the molar ratio of the polyalkylene polyamine to the alkyl glycidyl ether is 1:(2-3).

[0014] In any embodiment, the temperature of the ring-opening reaction is 110°C to 130°C.

[0015] In any embodiment, the time of the ring-opening reaction is 4 to 8 h.

[0016] In any embodiment, the polyalkylene polyamine is one or more of triethylene tetramine, tetraethylene pentamine and pentaethylene hexamine; and / or, the alkyl glycidyl ether is one or more of octyl glycidyl ether and dodecyl glycidyl ether; and / or, the solvent A is selected from one or two of N-N dimethylformamide and xylene.

[0017] In addition, the present specific embodiment also provides an application of the above-mentioned polyamine non-ionic demulsifier or the polyamine non-ionic demulsifier prepared by the above-mentioned preparation method in demulsifying crude oil emulsion.

[0018] In any embodiment, the polyamine non-ionic demulsifier is dissolved in solvent B to obtain a demulsifier solution, and then mixed with the crude oil emulsion for demulsification; the solvent B is one or more of water, ethanol and xylene.

[0019] Compared with the prior art, the beneficial effects of the present invention include: The polyamine-based non-ionic demulsifier proposed by the present invention uses polyethylenepolyamine as the hydrophilic central core. Through the ring-opening reaction of NH2 at both ends of polyethylenepolyamine with alkyl glycidyl ether, a hydrophobic long chain is introduced while an oxygen-containing group is introduced. The introduction of oxygen atoms increases the hydrogen bond sites on the demulsifier, making it easier to form hydrogen bonds with water molecules; when the demulsifier migrates to the oil-water interface, it will break the hydrogen bonds formed by natural surfactants such as asphaltenes and water molecules, and form an unstable composite film, thereby promoting the coalescence of water droplets and finally realizing oil-water separation; the hydrophilic part of this demulsifier is composed of NH and NH2 on polyethylenepolyamine, the hydroxyl groups obtained by the reaction of polyethylenepolyamine with alkylene oxide, and the ether groups on alkyl glycidyl ether. The hydrophobic part is composed of two alkyl chains. This demulsifier has the advantage of relatively concentrated hydrophilic groups, and has two hydrophobic long chains to assist its movement in the oil phase, further enabling it to have good demulsification effect at lower temperatures; the polyamine-based non-ionic demulsifier proposed by the present invention can exist stably at higher temperatures and is not easy to volatilize, indicating that it has many advantages such as non-flammability, high thermal stability and low volatility, and can effectively reduce the interfacial tension between oil and water. The polyamine-based non-ionic demulsifier proposed by the present invention has high surface activity, good thermal stability, good dispersibility in the oil phase, is applicable to petroleum crude oil emulsions, has high demulsification efficiency, low injection dosage, low demulsification temperature and fast demulsification rate; the method for preparing the demulsifier of the present invention has simple steps and low raw material cost. Description of the Drawings

[0020] Figure 1 Infrared spectrum of the polyamine-based non-ionic demulsifier prepared in Example 3.

[0021] Figure 2 Infrared spectrum of the polyamine-based non-ionic demulsifier prepared in Example 4. Detailed Embodiments

[0022] The "range" disclosed in the present application is defined in the form of a lower limit and an upper limit. A given range is defined by selecting a lower limit and an upper limit, and the selected lower limit and upper limit define the boundary of a particular range. The range defined in this way can include or exclude the end values and can be combined arbitrarily, 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, ranges of 60-110 and 80-120 are also contemplated. In addition, if the minimum range values 1 and 2 are listed, and if the maximum range values 3, 4, and 5 are listed, the following ranges are all contemplated: 1-3, 1-4, 1-5, 2-3, 2-4, and 2-5. In the present application, unless otherwise specified, the numerical range "a-b" represents an abbreviated representation of any real number combination between a and b, where a and b are both real numbers. For example, the numerical range "0-5" means that all real numbers between "0-5" are fully listed herein, and "0-5" is only an abbreviated representation of these numerical combinations. In addition, when stating that a certain parameter is an integer ≥2, it is equivalent to disclosing that the parameter is, for example, the integers 2, 3, 4, 5, 6, 7, 8, 9, 10, 11, 12, etc.

[0023] Unless otherwise specified, the "including" and "comprising" mentioned in the present application mean open-ended, and can also be closed-ended. For example, the "including" and "comprising" can mean that other components not listed can also be included or comprised, or can only include or comprise the listed components.

[0024] Unless otherwise specified, in the present application, the term "or" is inclusive. For example, the phrase "A or B" means "A, B, or both A and B". More specifically, any of the following conditions satisfies the condition "A or B": A is true (or exists) and B is false (or does not exist); A is false (or does not exist) while B is true (or exists); or both A and B are true (or exist).

[0025] This specific embodiment provides a polyamino non-ionic demulsifier, including one or more of the compounds having the following structural formulas:

[0026]

[0027] Among them, R1 and R2 are respectively selected from any one of C8-C 12 alkyl, and n is any integer from 4 to 6.

[0028] In some embodiments, R1 and R2 are respectively selected from one of C8-C 12 linear alkyl.

[0029] In some embodiments, R1 and R2 are the same.

[0030] This specific embodiment also provides a preparation method of the above-mentioned polyamine-based non-ionic demulsifier, which includes the following steps:

[0031] Using polyalkylene polyamine and alkyl glycidyl ether as raw materials, a ring-opening reaction occurs in solvent A to obtain the polyamine-based non-ionic demulsifier; the molar ratio of the polyalkylene polyamine to the alkyl glycidyl ether is 1:(2 - 3); the temperature of the ring-opening reaction is 110°C to 130°C, preferably but not limited to, the reaction temperature is 110°C, 115°C, 120°C, 125°C or 130°C, and the time of the ring-opening reaction is 4 to 8 hours, preferably but not limited to, the reaction time is 4 hours, 6 hours or 8 hours. The above reaction temperature needs to consider the solvent reflux temperature and ensure the smooth progress of the reaction. Too low a reaction temperature will lead to incomplete reaction, and too high a reaction temperature will evaporate the solvent. The reaction time can be appropriately extended within a suitable range, and within the above range, the impact on the reaction is relatively small.

[0032] In some embodiments, the polyalkylene polyamine is one or more of triethylene tetramine, tetraethylene pentamine and pentaethylene hexamine; the alkyl glycidyl ether is one or more of octyl glycidyl ether and dodecyl glycidyl ether; and / or, the solvent A is selected from one or both of N-N dimethylformamide and xylene.

[0033] The reaction formula is as follows:

[0034]

[0035] R is selected from any one of C8-C 12 alkyl.

[0036] The demulsifier prepared by the above method solves the problems of poor demulsification performance for crude oil, high raw material cost of the demulsifier and poor adaptability in the prior art.

[0037] This demulsifier has the advantages of simple synthesis steps, low demulsification temperature, fast demulsification rate and high demulsification efficiency. It is of great significance to solve the problems of long demulsification time, large injection dosage of chemical demulsifier and high demulsification temperature in the demulsification of crude oil emulsion in the petroleum industry. Due to its relatively concentrated hydrophilic groups and two hydrophobic long chains, it can move rapidly in the emulsion. This demulsifier has multiple oxygen-containing groups and multiple hydrogen bond sites. When it migrates to the oil-water interface, it will break the hydrogen bonds formed between asphaltene and water molecules and replace asphaltene, ultimately forming an unstable composite film, thereby promoting the coalescence of water droplets and finally realizing oil-water separation.

[0038] This specific embodiment also provides an application of the above polyamino nonionic demulsifier or the polyamino nonionic demulsifier prepared by the above preparation method in demulsifying crude oil emulsions; the polyamino nonionic demulsifier is dissolved in solvent B to obtain a demulsifier solution, and then mixed with the crude oil emulsion for demulsification; the solvent B is one or more of water, ethanol, and xylene; the mass fraction of the demulsifier in the demulsifier solution is 0.1 wt% to 0.5 wt%; the volume ratio of the demulsifier solution to the crude oil emulsion is 1:(10 - 20); the demulsification temperature is 40 - 60 °C, and the time is 60 - 180 min.

[0039] After the demulsification by the demulsifier of the present invention, the oil-water interface is clear, the water content in the oil phase is small, the demulsification temperature is low, and the dosage of the demulsifier is small.

[0040] In order to make the purpose, technical solution and advantages of the present invention clearer, the present 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 only used to explain the present invention and are not used to limit the present invention.

[0041] In the present invention, when referring to "some embodiments", "this embodiment" and examples, etc., they describe subsets of all possible embodiments. However, it can be 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.

[0042] If similar descriptions such as "first / second" appear in the application documents, the following explanation will be added. In the following description, the terms "first\second\third" only distinguish similar objects and do not represent a specific order for the objects. It can be understood that "first\second\third" can be interchanged with a specific order or sequence when allowed, so that the embodiments described here can be implemented in an order other than that illustrated or described here.

[0043] In this embodiment, the term "and / or" only describes the association relationship of associated objects, indicating that there can be three relationships. For example, object A and / or object B can represent: object A exists alone, object A and object B exist simultaneously, and object B exists alone.

[0044] Hereinafter, the embodiments of the present application will be described. The embodiments described below are exemplary and are only used to explain the present application and should not be construed as a limitation to the present application. For those not specified in the embodiments in terms of specific techniques or conditions, they shall be carried out according to the techniques or conditions described in the literature in the art or according to the product specifications. For the reagents or instruments not specified by the manufacturer, they are all conventional products that can be obtained through commercial purchase.

[0045] Example 1

[0046] This embodiment provides a polyamine-based nonionic demulsifier, which is obtained through the following steps:

[0047] Dissolve triethylenetetramine (1.46 g, 0.01 mol) completely in xylene solvent (20 mL), and add octyl glycidyl ether (3.72 g, 0.02 mol). The mixture is refluxed at 110 °C for 8 h. After evaporating the solvent, the target polyamine-based nonionic demulsifier is obtained, and its structure is shown in the following formula (I).

[0048]

[0049] Example 2

[0050] The main difference in the preparation method of the polyamine-based nonionic demulsifier in this embodiment from that in Example 1 is that dodecyl glycidyl ether is used to replace octyl glycidyl ether, specifically as follows:

[0051] This embodiment provides a polyamine-based nonionic demulsifier, which is obtained through the following steps:

[0052] Dissolve triethylenetetramine (1.46 g, 0.01 mol) completely in xylene solvent (20 mL), and add dodecyl glycidyl ether (4.85 g, 0.02 mol). The mixture is refluxed at 130 °C for 6 h. After evaporating the solvent, the target polyamine-based nonionic demulsifier is obtained, and its structure is shown in formula (II).

[0053]

[0054] Example 3

[0055] The main difference in the polyamine-based nonionic demulsifier in this embodiment from that in Example 1 is that tetraethylenepentamine is used to replace triethylenetetramine, specifically as follows:

[0056] This embodiment provides a polyamine-based nonionic demulsifier, which is obtained through the following steps:

[0057] Dissolve tetraethylenepentamine (1.89 g, 0.01 mol) completely in xylene solvent (20 mL), and add octyl glycidyl ether (3.72 g, 0.02 mol). The mixture is refluxed at 120 °C for 4 h. After evaporating the solvent, the target polyamine-based nonionic demulsifier is obtained, and its structure is shown in formula (III).

[0058]

[0059] Figure 1 The infrared spectrum of the demulsifier prepared in Example 3, where, approximately at 3300 cm -1The nearby peak corresponds to the stretching vibration of -OH. At 2929.38 cm -1 、2848.39 cm -1 and 721.25 cm -1 The observed absorption peaks are attributed to the stretching vibrations of -CH and -CH2, as well as the rocking vibration of -CH2. The peaks located at 1656.59 cm -1 and 1290.16 cm -1 correspond to the bending vibration of N-H and the stretching vibration of C-N respectively. The absorption peak at 1116.6 cm -1 corresponds to the stretching vibration of the C-O-C bond, indicating the successful preparation of the target product.

[0060] Example 4

[0061] The main difference between this example and Example 3 is that dodecyl glycidyl ether is used to replace octyl glycidyl ether, and other steps, conditions are the same as those in Example 3, which are as follows:

[0062] This example provides a polyamino nonionic demulsifier, which is obtained through the following steps:

[0063] Dissolve tetraethylenepentamine (1.89 g, 0.01 mol) completely in xylene solvent (20 mL), and add dodecyl glycidyl ether (4.85 g, 0.02 mol). The mixture is refluxed at 120 °C for 4 h. After evaporating the solvent, the target polyamino nonionic demulsifier is obtained, and its structure is shown in Formula (IV).

[0064]

[0065] Figure 2 is the infrared spectrum of the demulsifier prepared in Example 4. Among them, the peak near 3300 cm -1 corresponds to the stretching vibration of -OH. At 2929.38 cm -1 、2848.39 cm -1 and 721.25 cm -1 The observed absorption peaks are attributed to the stretching vibrations of -CH and -CH2, as well as the rocking vibration of -CH2. The peaks located at 1656.59 cm -1 and 1290.16 cm -1 correspond to the bending vibration of N-H and the stretching vibration of C-N respectively. The absorption peak at 1116.6 cm -1 corresponds to the stretching vibration of the C-O-C bond, indicating the successful preparation of the target product.

[0066] Example 5

[0067] The main difference between the preparation method of the demulsifier in this example and that in Example 1 is that pentaethylenehexamine is used to replace triethylenetetramine, and other steps, conditions are the same as those in Example 1, which are as follows:

[0068] This example presents a polyamine-based nonionic demulsifier, which is obtained through the following steps:

[0069] Dissolve pentaethylenehexamine (2.32 g, 0.01 mol) completely in xylene solvent (20 mL), and add octyl glycidyl ether (3.72 g, 0.02 mol). The mixture is refluxed at 120 °C for 4 h. After evaporating the solvent, the target polyamine-based nonionic demulsifier is obtained, and its structure is as shown in Formula V.

[0070]

[0071] Example 6

[0072] The main difference between Example 6 and Example 5 is that dodecyl glycidyl ether is used to replace octyl glycidyl ether, and other steps, conditions are the same as those in Example 5.

[0073] Dissolve pentaethylenehexamine (2.32 g, 0.01 mol) completely in xylene solvent (20 mL), and add dodecyl glycidyl ether (3.72 g, 0.02 mol). The mixture is refluxed at 120 °C for 4 h. After evaporating the solvent, the target polyamine-based nonionic demulsifier is obtained, and its structure is as shown in Formula VI.

[0074]

[0075] Test Example

[0076] To avoid redundancy, the crude oil emulsions used in the following tests are all prepared according to the following steps:

[0077] Add 150 parts by weight of crude oil to 350 parts by weight of deionized water, stir and mix, heat to 60 °C, and then stir at a speed of 11,000 r / min for 20 minutes. Repeat the stirring process one to three times until a stable water-in-oil emulsion, i.e., the crude oil emulsion, is obtained. To ensure the accuracy of the test, in this invention, the crude oil emulsion with the stirring process repeated three times is used for testing, and the mixing is more uniform.

[0078] 1. Using commercial demulsifier K3800 as Comparative Example 1, SP169 as Comparative Example 2, PDB9904 as Comparative Example 3, and PDB9360 as Comparative Example 4 for comparison, the demulsification performance of the demulsifiers prepared in Examples 1 - 6 in the crude oil emulsion was compared and tested. The specific steps are as follows:

[0079] The ionic liquids prepared in Examples 1 - 6 were respectively added to xylene / ethanol (75:25) to prepare solutions with a mass fraction of 0.6%, namely Experimental Groups 1 - 6; commercial demulsifier K3800 was used as Comparative Group 1, SP169 as Comparative Group 2, PDB9904 as Comparative Group 3, and PDB9360 as Comparative Group 4 for comparative experiments. The commercial demulsifiers in the comparative groups were added to xylene / ethanol (75:25) to prepare solutions with a mass fraction of 0.6%, namely Comparative Groups 1 - 4.

[0080] Experimental Groups 1 - 6 and Comparative Groups 1 - 4 were added to the above crude oil emulsion according to a volume ratio of 1:19, then fully shaken and mixed evenly, and then transferred to a 40°C water bath and left to stand for 0.5 h, and their dehydration rates were measured. The results are shown in Table 1.

[0081] Table 1 Demulsification results of Experimental Groups 1 - 6 and Comparative Groups 1 - 4

[0082] Group Demulsifier (mg / L) Demulsification efficiency (%) Experimental group 1 300 90.03 Experimental group 2 300 70 Experimental group 3 300 95.83 Experimental group 4 300 77.34 Experimental group 5 300 90.61 Experimental group 6 300 90.75 Control group 1 300 83 Control group 2 300 86 Control group 3 300 91 Control group 4 300 84

[0083] Note: "Demulsifier (mg / L)" in the table refers to the concentration of the demulsifier in the crude oil emulsion.

[0084] As can be seen from Table 1, the demulsifiers prepared in Examples 1 - 6 all have very good demulsification performance. However, due to different preparation conditions, such as the number of hydrophilic groups and the length of the alkyl hydrophobic chain, etc., the demulsification efficiency will vary. For example, it can be seen from Examples 1 and 2 that increasing the length of the carbon chain is not conducive to improving the demulsification performance, while it can be seen from Example 3 that appropriately increasing the number of amine groups is conducive to increasing the demulsification efficiency. Compared with Example 3, increasing the length of the alkyl chain in Example 4 caused a decrease in the demulsification rate. In Examples 5 and 6, the number of amine groups and the length of the alkyl chain were increased. It can be seen from Example 5 that the increase in the number of amine groups led to a decrease in the demulsification efficiency, which indicates that the hydrophilic-lipophilic balance of the demulsifier obtained in Example 3 reached the optimal value. Compared with the commercial demulsifiers in the comparative groups, the demulsification ability of the demulsifiers provided by the present invention also has more excellent effects.

[0085] 2. Solutions with different concentrations of the demulsifier prepared based on Example 3 were used to characterize the demulsification performance of the demulsifier with different concentrations in the crude oil emulsion.

[0086] Demulsifiers prepared in Example 1 with different weight parts were added to xylene / ethanol (75:25) to prepare demulsifiers with mass fractions of 1%, 0.8%, 0.6%, 0.4%, and 0.2% respectively. The obtained samples were denoted as Experimental Groups 7 - 11; the blank group was 0%, and the sample was denoted as Experimental Group 12.

[0087] Add 1 volume portion of the above experimental group 7 - 12 to 19 volume portions of the crude oil emulsion, then shake well to mix evenly, and then transfer it to a water bath at 40 °C and let it stand for 0.5 h. Measure its dehydration rate, and the results are shown in Table 2.

[0088] Table 2 Demulsification results of experimental group 7 - 12

[0089] Group Demulsifier (mg / L) Demulsification efficiency (%) Experimental group 7 500 98.34 Experimental group 8 400 96.85 Experimental group 9 300 93.45 Experimental group 10 200 90.84 Experimental group 11 100 0 Experimental group 12 0 0

[0090] Note: "Demulsifier (mg / L)" in the table refers to the concentration of the demulsifier in the crude oil emulsion.

[0091] As can be seen from Table 2, the demulsifier provided by the present invention has good demulsification performance. A demulsification efficiency of 90.84% can be achieved with a demulsifier concentration of 200 mg / L. When the concentration is 400 mg / L, the demulsification efficiency reaches 96.85%. When the concentration is 500 mg / L, the demulsification efficiency is 98.34%.

[0092] 3. Based on the demulsifier prepared in Example 1, experimental groups 13 - 17 were successively established to characterize the demulsification performance of the demulsifier at different temperatures and times.

[0093] Add the demulsifier prepared in Example 1 to xylene / ethanol (75:25) to prepare a solution with a mass fraction of 0.5%.

[0094] Add 1 volume portion of the above demulsifier to 19 volume portions of the crude oil emulsion, then shake well to mix evenly, and then transfer it to water baths set at different temperatures respectively and let it stand for 0.5 h. Measure its dehydration rate, and the results are shown in Table 3.

[0095] Table 3 Demulsification results of experimental groups 13 - 17

[0096]

[0097] As can be seen from Table 3: The demulsifier provided by the present invention can reach a demulsification efficiency of 98.34% in 30 min at 40 °C, 98.77% in 25 min at 50 °C; 94.33% in 5 min at 60 °C, and 100% in 10 min at 60 °C.

[0098] In summary, the demulsifier of the present invention has the advantages of simple synthesis steps, low demulsification temperature, fast demulsification rate, high demulsification efficiency, etc. It is of great significance for solving the problems of long demulsification time, large injection dose of chemical demulsifier, high demulsification temperature and other chemical demulsification problems in the petroleum industry. Due to its relatively concentrated hydrophilic groups and two hydrophobic long chains, the demulsifier of the present invention can move rapidly in the emulsion. The demulsifier has multiple oxygen-containing groups and multiple hydrogen bond sites. When it migrates to the oil-water interface, it will break the hydrogen bonds formed between asphaltene and water molecules and replace asphaltene, ultimately forming an unstable composite film to promote the coalescence of water droplets, and finally realizing the separation of oil and water.

[0099] The specific embodiments of the present invention described above do not constitute a limitation on the protection scope of the present invention. Any other corresponding changes and deformations made according to the technical concept of the present invention should be included in the protection scope of the claims of the present invention.

Claims

1. A polyamine-based nonionic demulsifier, characterized in that, Comprising one or more of the compounds having the following structural formula: Among them, R1 and R2 are each independently selected from any one of C8-C 12 alkyl groups, and n is any integer from 4 to 6.

2. The polyamine-based nonionic demulsifier according to claim 1, characterized in that, R1 and R2 are each independently selected from one of C8-C 12 linear alkyl groups.

3. The polyamine-based non-ionic demulsifier according to any one of claims 1-2, characterized in that, R1 and R2 are the same.

4. A preparation method of the polyamino nonionic demulsifier according to any one of claims 1-3, characterized in that, Comprising the following steps: Using polyethylenepolyamine and alkyl glycidyl ether as raw materials, an ring-opening reaction occurs in solvent A to obtain the polyamine-based nonionic demulsifier.

5. The preparation method of the polyamine-based nonionic demulsifier according to claim 4, characterized in that, The molar ratio of the polyethylenepolyamine to the alkyl glycidyl ether is 1:(2 - 3).

6. The preparation method of the polyamine-based nonionic demulsifier according to claim 4, characterized in that, The temperature of the ring-opening reaction is 110°C to 130°C.

7. The preparation method of the polyamino nonionic demulsifier according to claim 6, characterized in that, The time of the ring-opening reaction is 4 to 8 h.

8. The preparation method of the polyamino nonionic demulsifier according to claim 4, characterized in that, The polyethylenepolyamine is one or more of triethylenetetramine, tetraethylenepentamine, and pentaethylenehexamine; and / or, the alkyl glycidyl ether is one or more of octyl glycidyl ether and dodecyl glycidyl ether; and / or, the solvent A is selected from one or both of N-N dimethylformamide and xylene.

9. Use of the polyamine-based nonionic demulsifier according to any one of claims 1 - 3 or the polyamine-based nonionic demulsifier prepared by the preparation method according to any one of claims 4 - 8 in demulsifying crude oil emulsion.

10. The application according to claim 9, characterized in that, Dissolve the polyamine-based nonionic demulsifier in solvent B to obtain a demulsifier solution, and then mix it with the crude oil emulsion for demulsification; the solvent B is one or more of water, ethanol, and xylene.

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