Amphiphilic demulsifier as well as preparation method and application thereof

Abstract

The invention discloses an amphiphilic demulsifier as well as a preparation method and application thereof, and belongs to the technical field of oil-water emulsion treatment. The amphiphilic demulsifier is one or more of compounds with the following structural formula: # imgabs0 #, and R is selected from any one of C8-C18 alkyl groups. In addition, the invention also provides a preparation method of the amphiphilic demulsifier, which comprises the following steps: carrying out ring-opening reaction by using polyethylene glycol diglycidyl ether and diethanol amine as raw materials to obtain a first reactant; and carrying out esterification reaction on the first reactant and long-chain alkanoic acid in the presence of a solvent A and a catalyst to obtain the two-branch amphiphilic demulsifier. In addition, the invention also provides an application of the amphiphilic demulsifier or the amphiphilic demulsifier prepared by the preparation method in demulsification of crude oil emulsion. The amphiphilic demulsifier provided by the invention is high in surface activity, low in demulsification temperature and high in demulsification rate.

Description

Technical Field

[0001] The invention relates to the technical field of oil-water emulsion treatment, and in particular to an amphiphilic demulsifier and a preparation method and application thereof. Background Art

[0002] In the petroleum industry, the production of oil-water emulsions is very common. The production of emulsions will increase the viscosity of crude oil and thus increase transportation costs. Due to the presence of natural surfactants, the properties of this type of emulsion are very stable. The natural active substances in crude oil mainly include asphaltene, resin, cyclohexane acid and solid particles (clay or wax). These natural surfactants can spontaneously migrate to the oil-water interface to increase the strength of the interfacial film, thereby stabilizing the emulsion by preventing the aggregation of water droplets in the crude oil. Emulsions are usually harmful. Direct discharge will cause environmental pollution and damage the ecology. It will also affect the subsequent oil extraction, seriously corrode equipment, reduce pipeline availability and increase energy consumption, resulting in a decrease in recovery rate, making the production, processing and transportation of crude oil more difficult. Therefore, it is important and critical to separate the water phase from the crude oil emulsion before transportation and refining. Chemical demulsification is widely used because of its simple operation and fast demulsification rate and high demulsification efficiency.

[0003] Chemical demulsification is achieved by adding various chemical demulsifiers. Specifically, due to its amphiphilicity, the demulsifier can spontaneously migrate to the oil-water interface and replace the natural surfactants such as asphaltene at the interface, thereby forming an unstable composite film, making it easier for water droplets to aggregate and flocculate. Chemical demulsifiers mainly include polymer surfactants, nanoparticles and ionic liquids, such as ethylene oxide-propylene oxide (EO-PO) block copolymers, silicone polyethers, dendrimers, biodegradable polymer surfactants and nanoparticle-based demulsifiers.

[0004] However, these demulsifiers have problems such as complicated and dangerous 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 an amphiphilic demulsifier and a preparation method and application thereof, and solve the technical problem of poor demulsification performance of demulsifiers in the prior art.

[0006] In order to achieve the above technical objectives, the technical solution of the present invention provides a kind of affinity demulsifier, which is one or more of the compounds having the following structural formula:

[0007]

[0008] Wherein, R is selected from C8-C 18 Any of the alkyl groups.

[0009] In any embodiment, the R is selected from C8-C 18 A type of straight chain alkyl.

[0010] In any embodiment, the R is selected from

[0011] or

[0014] In addition, the present invention also provides a method for preparing the above-mentioned amphiphilic demulsifier, comprising the following steps:

[0015] Using polyethylene glycol diglycidyl ether and diethanolamine as raw materials to carry out a ring-opening reaction to obtain a first reactant;

[0016] The first reactant and the long-chain alkanoic acid are subjected to an esterification reaction in the presence of solvent A and a catalyst to obtain a two-branched amphiphilic demulsifier.

[0017] In any embodiment, the molar ratio of the polyethylene glycol diglycidyl ether to the diethanolamine is 1:(2-3); and / or the molar ratio of the polyethylene glycol diglycidyl ether to the long-chain alkanoic acid is 1:(2-3).

[0018] In any embodiment, the temperature of the ring-opening reaction is 110° C. to 130° C., and the time of the ring-opening reaction is 3 to 4 hours; and / or the temperature of the esterification reaction is 120 to 140° C., and the time of the esterification reaction is 4 to 6 hours.

[0019] In any embodiment, the long-chain alkanoic acid includes one or more of n-octanoic acid, dodecanoic acid and octadecanoic acid.

[0020] In any embodiment, the polyethylene glycol diglycidyl ether has an epoxy value of 0.70 to 0.80 mol / 100 g and a viscosity of 5 to 25 mPa.s at 25°C.

[0021] In any embodiment, the solvent A is xylene; and / or the catalyst is p-toluenesulfonic acid.

[0022] In addition, the present invention also proposes an application of the above amphiphilic demulsifier or the amphiphilic demulsifier prepared by the above preparation method in demulsifying crude oil emulsion.

[0023] Compared with the prior art, the beneficial effects of the present invention include: the amphiphilic demulsifier proposed in the present invention has high surface activity, good thermal stability, good dispersibility in the oil phase, is suitable for petroleum crude oil emulsions, has high demulsification efficiency, small injection dosage, low demulsification temperature and fast demulsification rate; and the preparation method of the demulsifier proposed in the present invention has simple steps and low raw material cost. BRIEF DESCRIPTION OF THE DRAWINGS

[0024] Figure 1 It is the infrared spectrum of the demulsifier prepared in Example 1 of the present invention.

[0025] Figure 2 It is the infrared spectrum of the demulsifier prepared in Example 2 of the present invention.

[0026] Figure 3 It is the infrared spectrum of the demulsifier prepared in Example 3 of the present invention. DETAILED DESCRIPTION

[0027] The "range" disclosed in the present application is defined in the form of a lower limit and an upper limit, and a given range is defined by selecting a lower limit and an upper limit, and the selected lower limit and upper limit define the boundaries of the particular range. The range defined in this way can be inclusive or exclusive of the end values, and can be arbitrarily combined, that is, any lower limit can be combined with any upper limit to form a range. For example, if a range of 60 to 120 and 80 to 110 is listed for a particular parameter, it is understood that a range of 60 to 110 and 80 to 120 is also expected. 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 can all be expected: 1 to 3, 1 to 4, 1 to 5, 2 to 3, 2 to 4 and 2 to 5. In the present application, unless otherwise specified, the numerical range "a to b" represents an abbreviation 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 listed in this document, and "0-5" is just an abbreviation of these numerical combinations. In addition, when a parameter is expressed as an integer ≥ 2, it is equivalent to disclosing that the parameter is, for example, an integer of 2, 3, 4, 5, 6, 7, 8, 9, 10, 11, 12, etc.

[0028] If there is no special explanation, the "include" and "comprising" mentioned in this application represent open-ended or closed-ended expressions. For example, the "include" and "comprising" may represent that other components not listed may also be included or only the listed components may be included or only the listed components may be included.

[0029] If not specifically stated, in this 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) and B is true (or exists); or both A and B are true (or exist).

[0030] This specific embodiment provides an amphiphilic demulsifier, which is one or more of the compounds having the following structural formulas:

[0031]

[0032] Wherein, R is selected from C8-C 18 Any of the alkyl groups.

[0033] In some embodiments, R is selected from C8-C 18 One of the straight chain alkyl groups; the R is preferably or

[0035] This specific embodiment also proposes a method for preparing the above-mentioned amphiphilic demulsifier, comprising the following steps:

[0036] Using polyethylene glycol diglycidyl ether and diethanolamine as raw materials for a ring-opening reaction to obtain a first reactant; the molar ratio of the polyethylene glycol diglycidyl ether to the diethanolamine is 1:(2-3); the temperature of the ring-opening reaction is 110° C. to 130° C., and the time of the ring-opening reaction is 3 to 4 hours;

[0037] The reaction formula is as follows:

[0038]

[0039] The first reactant and the long-chain alkanoic acid are subjected to an esterification reaction in the presence of solvent A and a catalyst to obtain a two-branched amphiphilic demulsifier; the molar ratio of the polyethylene glycol diglycidyl ether to the long-chain alkanoic acid is 1:(2-3); the temperature of the esterification reaction is 120-140°C, and the time of the esterification reaction is 4-6h; the epoxy value of the polyethylene glycol diglycidyl ether is 0.70-0.80mol / 100g, and the viscosity at 25°C is 5-25mpa.s.

[0040] The reaction formula is as follows:

[0041]

[0042] In some embodiments, the long-chain alkanoic acid includes one or more of octanoic acid, dodecanoic acid and octadecanoic acid, the solvent A is xylene; and / or the catalyst is p-toluenesulfonic acid.

[0043] The demulsifier of the present invention is subjected to a ring-opening reaction by -NH in diethanolamine and ethylene oxide on polyethylene glycol diglycidyl ether, and then a long-chain alkanoic acid and -OH on diethanolamine are subjected to an esterification reaction under the condition of the catalyst p-toluenesulfonic acid to obtain a two-branch amphiphilic demulsifier. The demulsifier has a relatively concentrated hydrophilic center and two hydrophobic long chains, and its two long carbon chains make it have better dispersibility and stronger interaction with natural surfactants in the oil phase, which can significantly change the tension at the oil-water interface, promote water droplet coalescence, and achieve oil-water separation; the middle hydrophilic part is composed of hydroxyl, amino group, etc., and polyethylene glycol diglycidyl ether is also hydrophilic as a whole, so that it has hydrophilicity. The two-branch amphiphilic demulsifier of the present invention can exist stably and is not easy to volatilize under high temperature conditions, indicating that it has many advantages such as non-flammable, high thermal stability and low volatility, and can effectively reduce the tension at the oil-water interface.

[0044] This specific embodiment also proposes the use of the above amphiphilic demulsifier or the amphiphilic demulsifier prepared by the above preparation method in demulsifying crude oil emulsion.

[0045] The 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 chemical demulsification problems in the petroleum industry, such as long demulsification time of crude oil emulsion, large injection dosage of chemical demulsifier and high demulsification temperature. Its two long carbon chains make it have better dispersibility in the oil phase and stronger interaction with natural surfactants, which can significantly change the tension at the oil-water interface, promote the coalescence of water droplets and achieve oil-water separation.

[0046] The demulsifier prepared by the preparation method proposed in the present invention solves the problems of poor demulsification performance for crude oil, high cost of demulsifier raw materials and poor adaptability in the prior art. After demulsification, the demulsifier of the present invention has a clear oil-water interface, low water content in the oil phase, low demulsification temperature and low dosage of demulsifier.

[0047] In order to make the purpose, technical solution and advantages of the present invention more clearly understood, the present invention is further described in detail below in conjunction with 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 intended to limit the present invention.

[0048] In the present invention, reference is made to “some embodiments”, “this embodiment”, examples, etc., which describe a subset of all possible embodiments, but it can be understood that “some embodiments” may be the same subset or different subsets of all possible embodiments and may be combined with each other without conflict.

[0049] If similar descriptions of "first / second" appear in the application documents, the following instructions are added. In the following description, the terms "first\second\third" involved are merely used to distinguish similar objects and do not represent a specific ordering of the objects. It can be understood that "first\second\third" can 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.

[0050] In this embodiment, the term "and / or" is merely a description of the association relationship between associated objects, indicating that three relationships may exist. For example, object A and / or object B may represent three situations: object A exists alone, object A and object B exist at the same time, and object B exists alone.

[0051] 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 limiting the present application. If no specific techniques or conditions are indicated in the embodiments, the techniques or conditions described in the literature in this area or the product specifications are used. If the manufacturer is not indicated in the reagents or instruments used, they are all conventional products that can be obtained commercially.

[0052] Example 1

[0053] This embodiment provides a two-branch amphiphilic demulsifier, which is obtained by the following steps:

[0054] Polyethylene glycol diglycidyl ether (2.62 g, 0.01 mol) and diethanolamine (2.1 g, 0.02 mol) were fully mixed, and the mixture was refluxed at 120° C. for 4 h. After the reaction, reactant 1 was obtained, and its structural formula is shown in Formula I:

[0055]

[0056] Then, dodecanoic acid (2 g, 0.02 mol) was dissolved in solvent xylene (30 mL), and then added to the above reactant 1, and the reactant 1 was stirred at 130° C. for 6 h in the presence of a catalyst p-toluenesulfonic acid to undergo an esterification reaction, and then the solvent xylene was distilled off to obtain the target demulsifier as shown in Formula II:

[0057]

[0058] Figure 1 This is the infrared spectrum of the demulsifier prepared in Example 1, 3330 cm -1 The peak at 2850cm is attributed to the stretching vibration of –OH. -1 The absorption peak at 1727cm corresponds to the stretching vibration of –CH2. -1 and 1400cm-1 The peaks near 1250cm represent the bending vibrations of C=O and CH. -1 and 1090cm -1 The peak at 700 cm is related to the stretching vibration of COC and CN. -1 The peaks near represent the rocking vibration of –CH2. Figure 1 The successful preparation of demulsifier is demonstrated.

[0059] Example 2

[0060] The main difference between Example 2 and Example 1 is that n-octanoic acid is used to replace dodecanoic acid, and the other steps and conditions are basically the same as those in Example 1.

[0061] This embodiment provides a two-branch amphiphilic demulsifier, which is obtained by the following steps:

[0062] Polyethylene glycol diglycidyl ether (2.62 g, 0.01 mol) and diethanolamine (2.1 g, 0.02 mol) were fully mixed without solvent, and the mixture was refluxed at 130° C. for 3 h. After the reaction was completed, reactant 1 was obtained.

[0063] Then, n-octanoic acid (0.02 mol) was dissolved in xylene (30 mL) and reacted with reactant 1 in the presence of a catalyst, p-toluenesulfonic acid, at 140° C. for 5 h, and then xylene was distilled off to obtain the target demulsifier as shown in Formula III.

[0064]

[0065] Figure 2 This is the infrared spectrum of the demulsifier prepared in Example 2, 3413 cm -1 The peak at 2850cm is attributed to the stretching vibration of –OH. -1 The absorption peak at 1725cm corresponds to the stretching vibration of –CH2. -1 and 1384cm -1 The peaks near 1263cm represent the bending vibrations of C=O and CH. -1 and 1095cm -1 The peak at 721 cm is related to the stretching vibration of COC and CN. -1 The peaks near represent the rocking vibration of –CH2. Figure 2 The successful preparation of demulsifier is demonstrated.

[0066] Example 3

[0067] The main difference between Example 3 and Example 1 is that octadecanoic acid is used to replace dodecanoic acid, and the other steps and conditions are basically the same as those in Example 1.

[0068] This embodiment provides a two-branch amphiphilic demulsifier, which is obtained by the following steps:

[0069] Polyethylene glycol diglycidyl ether (2.62 g, 0.01 mol) and diethanolamine (2.1 g, 0.02 mol) were fully mixed without solvent, and the mixture was refluxed at 110° C. for 4 h. After the reaction was completed, reactant 1 was obtained.

[0070] Then, octadecanoic acid (0.02 mol) was dissolved in xylene (30 mL) and reacted with reactant 1 in the presence of a catalyst, p-toluenesulfonic acid, at 120° C. for 6 h, and then xylene was distilled off to obtain the target demulsifier as shown in Formula IV.

[0071]

[0072] Figure 3 This is the infrared spectrum of the demulsifier prepared in Example 3, 3421 cm -1 The peak at 2859cm is attributed to the stretching vibration of –OH. -1 The absorption peak at 1733cm corresponds to the stretching vibration of –CH2. -1 and 1390cm -1 The peaks near 1263cm represent the bending vibrations of C=O and CH. -1 and 1093cm -1 The peak at 723 cm is related to the stretching vibration of COC and CN. -1 The peaks near represent the rocking vibration of –CH2. Figure 3 The successful preparation of demulsifier is demonstrated.

[0073] Test Case

[0074] To avoid redundancy, the crude oil emulsions used in the following tests were prepared according to the following steps:

[0075] 150 parts by weight of crude oil is added to 350 parts by weight of deionized water, stirred and mixed, heated to 60° C., and then stirred at a speed of 11000 r / min for 20 minutes. The stirring process is repeated one to three times until a stable oil-in-water emulsion, i.e., a crude oil emulsion, is obtained. To ensure the accuracy of the test, the crude oil emulsion that has been repeatedly stirred three times is tested in the present invention for more uniform mixing.

[0076] 1. The demulsification performance of the demulsifiers prepared in Examples 1 to 5 in crude oil emulsion was compared and tested by taking the commercial demulsifier DI18 as comparative example 1, 1301 as comparative example 2, PDB9392 as comparative example 3, PDB9958 as comparative example 4, and L64 as comparative example 5. The specific steps are as follows:

[0077] The demulsifiers prepared in Examples 1 to 3 were added to xylene / ethanol (75:25) to prepare solutions with a mass fraction of 1%, i.e., experimental groups 1-3; the commercial demulsifier DI18 was comparative example 1, 1301 was comparative example 2, PDB9392 was comparative example 3, PDB9958 was comparative example 4, and L64 was comparative example 5. Comparative experiments were performed as comparative groups 1-5, respectively, and the commercial demulsifiers in the comparative examples were added to xylene / ethanol (75:25) to prepare solutions with a mass fraction of 1%, i.e., comparative groups 1-5;

[0078] The experimental groups 1-3 and the comparative groups 1-5 were added to the above crude oil emulsion at a volume ratio of 1:19 and then fully shaken and mixed, and then transferred to a 50°C water bath and allowed to stand for 4 hours. The dehydration rate was measured. The results are shown in Table 1.

[0079] Table 1 Demulsification results of experimental groups 1-3 and comparative groups 1-5

[0080] Group Demulsifier(mg / L) Demulsification efficiency (%) Experimental Group 1 500 100 Experimental Group 2 500 94.37 Experimental Group 3 500 96.53 Comparison group 1 500 16.58 Comparison group 2 500 69.15 Comparison group 3 500 79.68 Comparison group 4 500 92.63 Comparison group 5 500 88.27

[0081] Note: "Demulsifier (mg / L)" in the table refers to the concentration of demulsifier in crude oil emulsion.

[0082] It can be seen from Table 1 that the demulsifiers prepared in Examples 1-3 all have very good demulsification performance, but the demulsification efficiency varies due to the different types of long-chain alkanoic acid used in the preparation process. It can be seen from Examples 1-3 that too long and too short carbon chains will affect the demulsification efficiency of the demulsifier. Compared with the commercial demulsifier in the comparison group, the demulsification ability of the demulsifier provided by the present invention also has a more excellent effect.

[0083] 2. Solutions of demulsifiers with different concentrations prepared in Example 1 were used to characterize the demulsification performance of demulsifiers with different concentrations in crude oil emulsions.

[0084] Different weight portions of the demulsifier prepared in Example 1 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 recorded as experimental groups 4-8; the blank group was 0%, and the sample was recorded as experimental group 9.

[0085] Table 2 Demulsification results of experimental groups 4-9

[0086]

[0087]

[0088] Note: "demulsifier (mg / L)" in the table refers to the concentration of the demulsifier in the crude oil emulsion. As shown in Table 2, the demulsifier provided by the present invention has good demulsification performance. The demulsification efficiency can reach 95.43% with 400 mg / L of demulsifier, and the demulsification efficiency reaches 99.85% when the concentration is 500 mg / L.

[0089] 3. Based on the demulsifier prepared in Example 1, experimental groups 12-15 were established in sequence to characterize the demulsification performance of the demulsifier at different temperatures and times.

[0090] The demulsifier prepared in Example 1 was added to xylene / ethanol (75:25) to prepare a solution with a mass fraction of 1%. The corresponding temperatures of experimental groups 12-15 were 40°C, 50°C, 60°C and 70°C, respectively.

[0091] 1 volume part of the above demulsifier was added to 19 volume parts of crude oil emulsion and then fully shaken to mix evenly, and then transferred to water baths set at different temperatures and allowed to stand for 3 hours. The dehydration rate was measured, and the results are shown in Table 3.

[0092] Table 3 Demulsification results of experimental groups 12-15

[0093]

[0094]

[0095] It can be seen from Table 3 that the demulsifier provided by the present invention can achieve a demulsification efficiency of 95.24% at 50°C for 150 minutes and a demulsification efficiency of 95.24% at 60°C for 90 minutes; it can reach a demulsification efficiency of 88.44% at 70°C for 30 minutes and a demulsification efficiency of 100% at 120 minutes.

[0096] 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 to solve the chemical demulsification problems such as long demulsification time of crude oil emulsion, large injection dosage of chemical demulsifier, and high demulsification temperature in the petroleum industry. Its two long carbon chains enable it to have better dispersibility in the oil phase and stronger interaction with natural surfactants, forming an unstable composite film at the interface to promote the coalescence of water droplets and complete oil-water separation.

[0097] The specific implementation of the present invention described above does not constitute a limitation on the protection scope of the present invention. Any other corresponding changes and modifications made based on the technical concept of the present invention should be included in the protection scope of the claims of the present invention.

Claims

1. An amphiphilic demulsifier, characterized in that: It is one or more of the compounds having the following structural formulas: Wherein, R is selected from C8-C 18 Any of the alkyl groups.

2. The amphiphilic demulsifier according to claim 1, characterized in that The R is selected from C8-C 18 A type of straight chain alkyl.

3. The amphiphilic demulsifier according to claim 2, characterized in that The R is selected from or 4. A method for preparing the amphiphilic demulsifier according to any one of claims 1 to 3, characterized in that: The following steps are involved: Using polyethylene glycol diglycidyl ether and diethanolamine as raw materials to carry out a ring-opening reaction to obtain a first reactant; The first reactant and the long-chain alkanoic acid are subjected to an esterification reaction in the presence of solvent A and a catalyst to obtain a two-branched amphiphilic demulsifier.

5. The method for preparing the amphiphilic demulsifier according to claim 4, characterized in that: The molar ratio of the polyethylene glycol diglycidyl ether to the diethanolamine is 1:(2-3); and / or the molar ratio of the polyethylene glycol diglycidyl ether to the long-chain alkanoic acid is 1:(2-3).

6. The method for preparing the amphiphilic demulsifier according to claim 4, characterized in that: The temperature of the ring-opening reaction is 110° C. to 130° C., and the time of the ring-opening reaction is 3 to 4 hours; and / or, the temperature of the esterification reaction is 120 to 140° C., and the time of the esterification reaction is 4 to 6 hours.

7. The method for preparing the amphiphilic demulsifier according to claim 4, characterized in that: The long-chain alkanoic acid includes one or more of octanoic acid, dodecanoic acid and octadecanoic acid.

8. The method for preparing the amphiphilic demulsifier according to claim 4, characterized in that: The epoxy value of the polyethylene glycol diglycidyl ether is 0.70-0.80 mol / 100 g, and the viscosity at 25° C. is 5-25 mPa.s.

9. The method for preparing the amphiphilic demulsifier according to claim 4, characterized in that: The solvent A is xylene; and / or the catalyst is p-toluenesulfonic acid.

10. Use of the amphiphilic demulsifier according to any one of claims 1 to 4 or the amphiphilic demulsifier prepared by the preparation method according to any one of claims 5 to 9 in demulsifying crude oil emulsion.

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