Low-temperature demulsifier, its preparation method and application

Abstract

The application provides a low-temperature demulsifier as well as a preparation method and application thereof, belongs to the technical field of oil-water emulsion treatment, and has the following structure: wherein R1 and R2 are both alkyl groups with C8-C 18 The demulsifier is a novel amphiphilic surfactant, has high surface activity and good thermal stability, and is good in dispersibility in an oil phase due to two long carbon chains and a hydrophilic center, has stronger action force with natural interface active substances, thereby destroys an interface film composed of asphaltene, and promotes the occurrence of a demulsification process. The demulsifier is especially suitable for oil crude emulsion, has high demulsification efficiency, small injection dose, fast demulsification rate, and obvious demulsification effect, and the separated water phase is clear. The method for preparing the demulsifier has simple steps, low raw material price, and no need of complicated separation equipment and expensive instruments and equipment, so that the production cost of the demulsifier can be greatly reduced.

Description

TECHNICAL FIELD

[0001] The present application relates to the technical field of oil-water emulsion treatment, and particularly relates to a low-temperature demulsifier and a preparation method and application thereof. BACKGROUND

[0002] Crude oil contains a large amount of non-hydrocarbon impurities and inorganic salts. Meanwhile, for most oilfields in China, the crude oil has entered the middle and late stages of development, and the content of gum and asphaltene in the crude oil has increased significantly, which puts forward higher requirements for the demulsification treatment of the crude oil. In fact, it is very important to demulsify the crude oil. The impurities contained in the crude oil can increase the operating load of the conveying equipment, and the free water in the crude oil can cause environmental pollution problems. Therefore, the demulsification treatment of the crude oil has good economic value and environmental value. At present, commonly used demulsification technologies at home and abroad include electric demulsification, thermal demulsification, biological demulsification, mechanical demulsification, membrane separation and chemical demulsification. Among them, the chemical demulsification method is a commonly used demulsification method due to its rapidness and low consumption.

[0003] There are many types of chemical demulsifiers, which can be mainly divided into six types: polymer type, derivative type, compound type, high molecular weight demulsifier, multi-component type and trimer type. The high molecular weight demulsifier is mainly composed of ethylene carbonate, and compared with the ethylene oxide type demulsifier, the application effect of the high molecular weight demulsifier is relatively good. The multi-component type demulsifier has a relatively wide application range and a relatively wide concentration range in use. The trimer type demulsifier is mainly composed of acrylamide and methacrylate. The demulsifier has amphiphilic properties of hydrophilic and hydrophobic, can be adsorbed on the oil-water interface, break the rigid interface film between the natural emulsifier and the surfactant, and then reduce the stability of the emulsion, so as to achieve the purpose of oil-water separation. The demulsifier has properties similar to emulsifiers, but has high surface activity and low interfacial tension, and can replace emulsifiers on the oil-water interface, so as to promote the flocculation and coalescence of droplets. In order to destroy the interface film formed by the emulsifier, the demulsifier needs to have high surface activity and low interfacial tension. However, these demulsifiers have complex preparation process, high raw material cost and complex synthesis process. SUMMARY

[0004] In view of the technical problems in the background art, the present application provides a low-temperature demulsifier and a preparation method and application thereof, which aims to solve the technical problems of complex preparation process and high raw material cost of the demulsifier.

[0005] In a first aspect, the embodiments of the present application provide a low-temperature demulsifier, which has the following structure:

[0006] ;

[0007] wherein R1 and R2 are both C8~C18 Alkyl groups of carbon atoms;

[0008] The n is an integer greater than or equal to 1.

[0009] Secondly, embodiments of this application provide a method for preparing a low-temperature demulsifier, comprising the following steps: using ethyleneamine compounds and alkyl acrylates as raw materials, mixing them in a first solvent and reacting them, wherein the molar ratio of ethyleneamine compounds to alkyl acrylates is 1:(1~4), and after the reaction is completed, the excess solvent is evaporated to obtain the low-temperature demulsifier, wherein the ethyleneamine compounds contain two or more vinyl groups.

[0010] Preferably, the ethyleneamine compound is a polyethylenepolyamine.

[0011] Preferably, the ethyleneamine compounds include one or more of triethylenetetramine, tetraethylenepentamine, and pentaethylenehexamine.

[0012] Preferably, the alkyl acrylate includes one or more of octyl acrylate, dodecyl acrylate, and octadecyl acrylate.

[0013] Preferably, the first solvent includes one or more of methanol, xylene, and diethyl ether.

[0014] Preferably, the reaction temperature is 60~80℃ and the reaction time is 22~24h.

[0015] Thirdly, this application provides an application of a low-temperature demulsifier in the demulsification of crude oil emulsions, comprising the following steps: dispersing the demulsifier in a second solvent to obtain a mixed solution; mixing the mixed solution with the crude oil emulsion evenly, heating to 50~60℃ and letting it stand for 0.5~2.5h to complete the demulsification of the crude oil emulsion.

[0016] Preferably, the second solvent includes one or more of water, ethanol, and xylene.

[0017] Preferably, the mass fraction of the demulsifier in the mixed solution is 0.2-1%; the volume ratio of the mixed solution to the crude oil emulsion is 1:(10-20).

[0018] The advantages of this application, which differ from existing technical solutions, include:

[0019] The demulsifier of the present application is a new type of amphiphilic surfactant, which has high surface activity, good thermal stability, two long carbon chains and a hydrophilic center, so that it has good dispersibility in the oil phase, stronger force with natural interface active substances, thereby destroying the interface film composed of asphaltene, and promoting the occurrence of the demulsification process. It is especially suitable for oil crude oil emulsion, has high demulsification efficiency, small injection dose, fast demulsification rate, and obvious demulsification effect, and the separated water phase is clear. The method for preparing the demulsifier of the present application has simple steps, low raw material price, and does not need complex separation equipment and expensive instrument equipment, so that the production cost of the demulsifier can be greatly reduced.

[0020] The above description is only a summary of the technical scheme of the present application, in order to more clearly understand the technical means of the present application, and can be implemented according to the content of the specification, and in order to make the above and other purposes, characteristics and advantages of the present application more obvious and easy to understand, the following specific embodiments of the present application are described. BRIEF DESCRIPTION OF DRAWINGS

[0021] In order to more clearly illustrate the technical scheme of the present application, the drawings used in the present application will be briefly introduced below. Obviously, the drawings described below are only some embodiments of the present application, and other drawings can be obtained by those skilled in the art without creative labor on the basis of these drawings.

[0022] Figure 1 The infrared spectrum of the demulsifier prepared in Example 1;

[0023] Figure 2 The demulsification performance diagram of the demulsifier prepared in Example 1. DETAILED DESCRIPTION

[0024] The embodiments of the technical scheme of the present application will be described in detail below with reference to the drawings. The following examples are only used to more clearly illustrate the technical scheme of the present application, and therefore only serve as examples, and cannot limit the protection scope of the present application.

[0025] Unless otherwise defined, all technical and scientific terms used herein have the same meaning as commonly understood by one of ordinary skill in the art to which the present application belongs; the terms used herein are only for the purpose of describing specific embodiments, and are not intended to limit the present application; the terms "include" and "have" in the specification and claims of the present application and the above description of drawings are intended to cover non-exclusive inclusion.

[0026] In the description of the embodiments of the present application, the technical terms "first", "second", etc. are only used to distinguish different objects, and cannot be understood as indicating or implying relative importance or implicitly indicating the number, specific order or primary and secondary relationship of the indicated technical features. In the description of the embodiments of the present application, the meaning of "a plurality of" is more than two, unless otherwise explicitly and specifically limited.

[0027] Reference herein to "embodiments" means that a particular feature, structure, or characteristic described in connection with an embodiment can be included in at least one embodiment of the application. The appearance of the phrase in various places in the specification does not necessarily all refer to the same embodiment, nor is it necessarily independent or alternative embodiments to each other. It is explicitly and implicitly understood by those skilled in the art that the embodiments described herein can be combined with other embodiments.

[0028] In the description of the embodiments of the present application, the term "a plurality of" refers to more than two (including two), and similarly, "a plurality of groups" refers to more than two groups (including two groups), and "a plurality of pieces" refers to more than two pieces (including two pieces).

[0029] Demulsifiers have properties similar to emulsifiers, but have high surface activity and low interfacial tension, which can replace emulsifiers at the oil-water interface to promote the flocculation and coalescence of droplets. In order to break the interfacial film formed by the emulsifier, the demulsifier needs to have high surface activity and low interfacial tension. However, these demulsifiers have complex preparation process, high raw material cost and complex synthesis process.

[0030] In order to solve the technical problems of complex preparation process, high raw material cost and complex synthesis process of demulsifiers, the present application provides a low-temperature demulsifier, which has the following structure:

[0031] ;

[0032] Wherein R1 and R2 are both alkyl groups with C8~C 18 carbon atoms;

[0033] The n is an integer greater than or equal to 1.

[0034] In the technical scheme of the embodiment of the application, the demulsifier in the application is a new type of amphoteric surfactant (hydrophilic center and two hydrophobic long carbon chains), which has strong dispersibility, can be well dissolved in solvents such as water, ethanol, dimethylbenzene and the like, and can effectively reduce the interfacial tension of oil and water. By changing the wettability, surface tension and interfacial tension of oil and water, the regulation of the interfacial tension of oil and water is realized. The demulsifier has simple preparation process, low demulsification temperature and high demulsification rate. The problems of long emulsification time of petroleum crude oil, large amount of chemical demulsifier and high demulsification temperature are solved. Compared with conventional demulsifiers, the surface activity of the demulsifier is obviously improved. The two hydrophobic long chains endow the polymer with good dispersing ability in the oil phase, and also enhance the adsorption capacity of the natural interfacial active substances.

[0035] In a second aspect, the embodiment of the application provides a preparation method of a low-temperature demulsifier, including the following steps: using ethylene amine compounds and alkyl acrylate as raw materials, mixing in a first solvent and then reacting, and after the reaction is completed, spinning out the excess solvent to obtain the low-temperature demulsifier. The ethylene amine compounds contain two or more ethylene groups.

[0036] In the technical scheme of the embodiment of the application, the reaction equation is as follows:

[0037] .

[0038] The raw materials used in the above method are cheap and easy to obtain, the reaction process is simple, and the low-temperature demulsifier can be prepared by one-step method. The prepared demulsifier has good demulsification performance, and solves the problems of poor demulsification performance of crude oil, high cost of demulsifier raw materials and poor adaptability in the prior art.

[0039] Preferably, the ethylene amine compound is a polyethylene polyamine.

[0040] Preferably, the ethylene amine compound includes one or more of triethylene tetramine, tetraethylene pentamine and pentaethylene hexamine.

[0041] Preferably, the alkyl acrylate includes one or more of octyl acrylate, dodecyl acrylate and octadecyl acrylate.

[0042] Preferably, the first solvent includes one or more of methanol, dimethylbenzene and diethyl ether.

[0043] Preferably, the molar ratio of the ethylene amine compound and the alkyl acrylate is 1: (1-4).

[0044] Preferably, the reaction temperature is 60-80℃, and the reaction time is 22-24h.

[0045] In the technical scheme of the embodiment of the present application, in order to facilitate understanding of the reaction process of the present application, dodecyl acrylate is selected instead of alkyl acrylate, xylene is selected as the solvent, and the demulsifier is prepared after mixing with polyethylene polyamine under the set conditions, and the specific steps are as follows:

[0046] The polyethylene polyamine and the dodecyl acrylate are mixed in the xylene at normal temperature, the mixture is reacted at 60 DEG C for 24 h, after the reaction is completed, the xylene is removed by rotary evaporation, and the product is obtained, and the reaction formula is shown as formula I:

[0047]

[0048] (I).

[0049] In a third aspect, the embodiment of the present application provides an application of the low-temperature demulsifier in demulsification of crude oil emulsion, including the following steps: dispersing the demulsifier in a second solvent to obtain a mixed solution; uniformly mixing the mixed solution with the crude oil emulsion, heating to 50-60 DEG C, and then standing for 0.5-2.5 h, so that the demulsification of the crude oil emulsion is completed.

[0050] Preferably, the second solvent includes one or more of water, ethanol and xylene.

[0051] Preferably, the mass fraction of the demulsifier in the mixed solution is 0.2-1%, and the volume ratio of the mixed solution to the crude oil emulsion is 1: (10-20).

[0052] In the technical scheme of the embodiment of the present application, the demulsifier in the present application is used for demulsification of the crude oil emulsion, after the demulsification is completed, the water phase is clear, the oil-water interface is clear, the demulsification efficiency is high, and the demulsification time is short.

[0053] Some specific embodiments are listed below, and it should be noted that the embodiments described below are exemplary and are used to explain the present application, and cannot be understood as a limitation on the present application. If the specific technology or condition is not specified in the embodiments, the technology or condition described in the literature in the art or according to the product manual is used. If the reagent or instrument is not specified by the manufacturer, it is a conventional product that can be obtained from the market.

[0054] I. Preparation method

[0055] Example 1

[0056] A preparation method of a low-temperature demulsifier is obtained by the following steps:

[0057] 0.02 mol of dodecyl acrylate and 0.01 mol of polyethylene polyamine are added into 20 mL of xylene at normal temperature, after mixing, the mixture is reacted at 60 DEG C for 24 h, after the reaction is completed, the excess xylene is removed by rotary evaporation, and the demulsifier is obtained.

[0058] Example 2

[0059] The difference from Example 1 is that the polyethylene polyamine is replaced by tetraethylene pentamine, and other steps and conditions are the same as Example 1; specifically:

[0060] Under normal temperature conditions, 0.02 mol of dodecyl acrylate and 0.01 mol of tetraethylene pentamine are added to 20 mL of xylene, mixed, and then reacted at 60°C for 24 h. After the reaction is completed, the excess xylene is spin-evaporated to obtain the demulsifier.

[0061] Example 3

[0062] The difference from Example 1 is that the polyethylene polyamine is replaced by pentaethylene hexamine, and other steps and conditions are the same as Example 1; specifically:

[0063] Under normal temperature conditions, 0.02 mol of dodecyl acrylate and 0.01 mol of pentaethylene hexamine are added to 20 mL of xylene, mixed, and then reacted at 60°C for 24 h. After the reaction is completed, the excess xylene is spin-evaporated to obtain the demulsifier.

[0064] Example 4

[0065] The difference from Example 1 is that the dodecyl acrylate is replaced by octadecyl acrylate, and other steps and conditions are the same as Example 1; specifically:

[0066] Under normal temperature conditions, 0.02 mol of octadecyl acrylate and 0.01 mol of polyethylene polyamine are added to 20 mL of xylene, mixed, and then reacted at 60°C for 24 h. After the reaction is completed, the excess xylene is spin-evaporated to obtain the demulsifier.

[0067] Example 5

[0068] The difference from Example 4 is that the solvent is replaced by diethyl ether, and other steps and conditions are the same as Example 4; specifically:

[0069] Under normal temperature conditions, 0.02 mol of octadecyl acrylate and 0.01 mol of polyethylene polyamine are added to 20 mL of diethyl ether, mixed, and then reacted at 60°C for 24 h. After the reaction is completed, the excess diethyl ether is spin-evaporated to obtain the demulsifier.

[0070] Example 6

[0071] The demulsifier prepared in Example 1 is applied in crude oil emulsion, including the following steps:

[0072] 150 parts by weight of crude oil was added to 350 parts by weight of deionized water and stirred to mix, heated to 60℃, then stirred at 11000 r / min for 20 minutes to obtain a stable water-in-oil emulsion, i.e. crude oil emulsion.

[0073] The demulsifier prepared in Example 1 was added to xylene / ethanol (75:25) to prepare a solution with a mass fraction of 1%, i.e. experimental group 1, which was added to the above-mentioned crude oil emulsion in a volume ratio of 1:19 and then fully mixed by oscillation, and then transferred to a 45℃ water bath for 4h, i.e. the demulsification of the crude oil emulsion was completed.

[0074] Example 7

[0075] Example 7 differs from Example 6 in that the demulsifier prepared in Example 2 was added to xylene / ethanol (75:25) to prepare a solution with a mass fraction of 1%, i.e. experimental group 2, which was added to the above-mentioned crude oil emulsion in a volume ratio of 1:19 and then fully mixed by oscillation, and then transferred to a 45℃ water bath for 4h, i.e. the demulsification of the crude oil emulsion was completed.

[0076] Example 8

[0077] Example 8 differs from Example 6 in that the demulsifier prepared in Example 3 was added to xylene / ethanol (75:25) to prepare a solution with a mass fraction of 1%, i.e. experimental group 3, which was added to the above-mentioned crude oil emulsion in a volume ratio of 1:19 and then fully mixed by oscillation, and then transferred to a 45℃ water bath for 4h, i.e. the demulsification of the crude oil emulsion was completed.

[0078] Example 9

[0079] Example 9 differs from Example 6 in that the demulsifier prepared in Example 4 was added to xylene / ethanol (75:25) to prepare a solution with a mass fraction of 1%, i.e. experimental group 4, which was added to the above-mentioned crude oil emulsion in a volume ratio of 1:19 and then fully mixed by oscillation, and then transferred to a 45℃ water bath for 4h, i.e. the demulsification of the crude oil emulsion was completed.

[0080] Example 10

[0081] Example 10 differs from Example 6 in that the demulsifier prepared in Example 5 was added to xylene / ethanol (75:25) to prepare a solution with a mass fraction of 1%, i.e. experimental group 5, which was added to the above-mentioned crude oil emulsion in a volume ratio of 1:19 and then fully mixed by oscillation, and then transferred to a 45℃ water bath for 4h, i.e. the demulsification of the crude oil emulsion was completed.

[0082] Example 11

[0083] 150 parts by weight of crude oil was added to 350 parts by weight of deionized water and mixed with stirring, heated to 60°C, and then stirred at 11000 r / min for 20 minutes to obtain a stable water-in-oil emulsion.

[0084] The demulsifier prepared in Example 1 was added to xylene / ethanol (75:25) to prepare a demulsifier with a mass fraction of 1%, and the sample obtained was recorded as Experimental Group 6. 1 part by volume of the above Experimental Group 6 was added to 19 parts by volume of the crude oil emulsion and then mixed uniformly by oscillation, and then transferred to a 45°C water bath and allowed to stand for 4h to complete the demulsification of the crude oil emulsion.

[0085] Example 12

[0086] Example 12 differs from Example 11 in that the demulsifier prepared in Example 1 was added to xylene / ethanol (75:25) to prepare a demulsifier with a mass fraction of 0.8%, and the sample obtained was recorded as Experimental Group 7. 1 part by volume of the above Experimental Group 7 was added to 19 parts by volume of the crude oil emulsion and then mixed uniformly by oscillation, and then transferred to a 45°C water bath and allowed to stand for 4h to complete the demulsification of the crude oil emulsion.

[0087] Example 13

[0088] Example 13 differs from Example 11 in that the demulsifier prepared in Example 1 was added to xylene / ethanol (75:25) to prepare a demulsifier with a mass fraction of 0.6%, and the sample obtained was recorded as Experimental Group 8. 1 part by volume of the above Experimental Group 8 was added to 19 parts by volume of the crude oil emulsion and then mixed uniformly by oscillation, and then transferred to a 45°C water bath and allowed to stand for 4h to complete the demulsification of the crude oil emulsion.

[0089] Example 14

[0090] Example 14 differs from Example 11 in that the demulsifier prepared in Example 1 was added to xylene / ethanol (75:25) to prepare a demulsifier with a mass fraction of 0.4%, and the sample obtained was recorded as Experimental Group 9. 1 part by volume of the above Experimental Group 9 was added to 19 parts by volume of the crude oil emulsion and then mixed uniformly by oscillation, and then transferred to a 45°C water bath and allowed to stand for 4h to complete the demulsification of the crude oil emulsion.

[0091] Example 15

[0092] Example 15 differs from Example 11 in that the demulsifier prepared in Example 1 was added to xylene / ethanol (75:25) to make a 0.2% by mass solution of the demulsifier, and the resulting sample was labeled Sample 10. One volume part of Sample 10 was added to 19 volume parts of the crude oil emulsion and mixed well by shaking, and then transferred to a water bath at 45°C and left to stand for 4 hours to complete the demulsification of the crude oil emulsion.

[0093] Example 16

[0094] Example 16 differs from Example 11 in that the demulsifier prepared in Example 1 was added to xylene / ethanol (75:25) to make a 0% by mass solution of the demulsifier, and the resulting sample was labeled Sample 11. One volume part of Sample 11 was added to 19 volume parts of the crude oil emulsion and mixed well by shaking, and then transferred to a water bath at 45°C and left to stand for 4 hours to complete the demulsification of the crude oil emulsion.

[0095] Example 17

[0096] One hundred and fifty parts by weight of crude oil was added to 350 parts by weight of deionized water and mixed by stirring, and then heated to 60°C and stirred at 11000 rpm for 20 minutes to obtain a stable water-in-oil emulsion.

[0097] The demulsifier prepared in Example 1 was added to xylene / ethanol (75:25) to make a 1% by mass solution.

[0098] One volume part of the above demulsifier was added to 19 volume parts of the crude oil emulsion and mixed well by shaking, and then transferred to a water bath at 40°C and left to stand, and labeled Sample 12 to complete the demulsification of the crude oil emulsion.

[0099] Example 18

[0100] Example 18 differs from Example 17 in that one volume part of the above demulsifier was added to 19 volume parts of the crude oil emulsion and mixed well by shaking, and then transferred to a water bath at 45°C and left to stand, and labeled Sample 13 to complete the demulsification of the crude oil emulsion.

[0101] Example 19

[0102] Example 19 differs from Example 17 in that one volume part of the above demulsifier was added to 19 volume parts of the crude oil emulsion and mixed well by shaking, and then transferred to a water bath at 50°C and left to stand, and labeled Sample 14 to complete the demulsification of the crude oil emulsion.

[0103] Example 20

[0104] Example 20 is different from Example 17 in that 1 part by volume of the above demulsifier is added to 19 parts by volume of the crude oil emulsion and then mixed uniformly by oscillation, and then transferred to a water bath at 55°C and allowed to stand, denoted as Experiment Group 15, to complete the demulsification of the crude oil emulsion.

[0105] Comparative Example 1

[0106] Comparative Example 1 is different from Example 6 in that the commercial demulsifier RI-14A is used, added to xylene / ethanol (75:25), prepared into a solution with a mass fraction of 1%, to obtain Comparative Group 1, which is added to the above crude oil emulsion in a volume ratio of 1:19 and then mixed uniformly by oscillation, and then transferred to a water bath at 45°C and allowed to stand for 4h, to complete the demulsification of the crude oil emulsion.

[0107] Comparative Example 2

[0108] Comparative Example 2 is different from Example 6 in that the commercial demulsifier PE10100 is used, added to xylene / ethanol (75:25), prepared into a solution with a mass fraction of 1%, to obtain Comparative Group 2, which is added to the above crude oil emulsion in a volume ratio of 1:19 and then mixed uniformly by oscillation, and then transferred to a water bath at 45°C and allowed to stand for 4h, to complete the demulsification of the crude oil emulsion.

[0109] Comparative Example 3

[0110] Comparative Example 3 is different from Example 6 in that the commercial demulsifier DI-18 is used, added to xylene / ethanol (75:25), prepared into a solution with a mass fraction of 1%, to obtain Comparative Group 3, which is added to the above crude oil emulsion in a volume ratio of 1:19 and then mixed uniformly by oscillation, and then transferred to a water bath at 45°C and allowed to stand for 4h, to complete the demulsification of the crude oil emulsion.

[0111] Comparative Example 4

[0112] Comparative Example 4 is different from Example 6 in that the commercial demulsifier K3800 is used, added to xylene / ethanol (75:25), prepared into a solution with a mass fraction of 1%, to obtain Comparative Group 4, which is added to the above crude oil emulsion in a volume ratio of 1:19 and then mixed uniformly by oscillation, and then transferred to a water bath at 45°C and allowed to stand for 4h, to complete the demulsification of the crude oil emulsion.

[0113] II. Test Method

[0114] Crude oil emulsion dehydration rate test method: The distillation method in GBT8929-2006 is used to test the dehydration rate of the crude oil emulsion.

[0115] III. Analysis of Test Results of Each Example and Comparative Example

[0116] (1) Figure 1 The infrared spectrum of the demulsifier prepared in Example 1 is shown in Figure 1. Figure 1 It can be seen that the peak at 3285.16 cm -1 corresponds to the stretching vibration of O-H, the peaks at 2921.67 cm -1 and 2849.21 cm -1 correspond to the asymmetric and symmetric stretching vibrations of C-H, respectively. The peak at 1730.98 cm -1 is attributed to the vibration of C=O, the absorption peaks at 1641.21 cm -1 and 724.08 cm -1 represent the in-plane and out-of-plane bending vibrations of N-H. In addition, the peak at 1462.38 cm -1 is caused by the in-plane bending vibration of C-H. The peak at 1177.26 cm -1 represents the stretching vibration of C-O-C. Furthermore, the peak at 1048.70 cm -1 corresponds to the stretching vibration of C-N. Thus, it is shown that the demulsifier of Formula I is successfully prepared by the method in Example 1.

[0117] (2) The demulsifiers prepared in Examples 1-5 were added to xylene / ethanol (75:25) respectively to prepare a solution with a mass fraction of 1%, i.e. experimental groups 1-5. Commercial demulsifiers RI-14A, PE10100, DI-18 and K3800 were used as comparative examples 1, 2, 3 and 4, respectively, to perform comparative experiments. The commercial demulsifiers in the comparative examples were added to xylene / ethanol (75:25) to prepare a solution with a mass fraction of 1%, i.e. comparative groups 1-4.

[0118] The experimental groups 1-5 and comparative groups 1-4 were added to the above-mentioned crude oil emulsion in a volume ratio of 1:19, then mixed uniformly by oscillation, and then transferred to a 45℃ water bath for 4h. The dehydration rate was measured, and the results are shown in Table 1.

[0119] Table 1 Demulsification results of experimental groups 1-5 and comparative groups 1-4

[0120]

[0121] Note: “Demulsifier (mg / L)” in the table refers to the concentration of the demulsifier in the crude oil emulsion.

[0122] From Table 1, it can be seen that the demulsifiers prepared in Examples 1-3 all have very good demulsification performance, but the demulsification efficiency will be different due to different preparation conditions. The demulsifiers prepared in Examples 4 and 5 have slightly lower efficiency than the previous three, and cannot better interact with natural interfacial active substances to destroy the interfacial film. However, compared with the commercial demulsifiers in the comparative group, the demulsification ability of the demulsifiers provided by the application also has good effect.

[0123] (3) Based on the demulsifier prepared in Example 1, solutions with different concentrations of the demulsifier were used to characterize the demulsification performance of the demulsifier in crude oil emulsion. Different weight parts of the demulsifier prepared in Example 1 were added to dimethylbenzene / ethanol (75:25) to prepare demulsifiers with mass fractions of 1%, 0.8%, 0.6%, 0.4%, and 0.2%, respectively. The obtained samples are denoted as experimental groups 6-10. The blank group is 0%, and the sample is denoted as experimental group 11.

[0124] 1 part by volume of the above experimental groups 6-11 was added to 19 parts by volume of crude oil emulsion, then mixed uniformly by oscillation, and then transferred to a 45℃ water bath for 4h. The dehydration rate was measured, and the results are shown in Table 2 and Figure 2

[0125] Table 2 Demulsification results of experimental groups 6-11

[0126]

[0127] Note: In the table, "demulsifier (mg / L)" refers to the concentration of the demulsifier in the crude oil emulsion.

[0128] From Table 2, it can be seen that the demulsifier provided by the application has good demulsification performance. With 300mg / L of the demulsifier, the demulsification efficiency can reach 99.85%. When the concentration is 400mg / L and 500mg / L, the demulsification efficiency reaches 100%.

[0129] As shown in Figure 2 , after demulsification, the water phase is clear, the oil-water interface is clear, and the water content in the oil phase is small. The demulsifier provided by the application has high demulsification efficiency and short demulsification time.

[0130] (4) Based on the demulsifier prepared in Example 1, experimental groups 12-15 were established in turn to characterize the demulsification performance of the demulsifier at different temperatures and times.

[0131] The demulsifier prepared in Example 1 was added to dimethylbenzene / ethanol (75:25) to prepare a solution with a mass fraction of 1%.

[0132] ​1 part by volume of the above demulsifier was added to 19 parts by volume of the crude oil emulsion and then mixed uniformly by oscillation, and then transferred to a water bath set at different temperatures and allowed to stand, and the dehydration rate was measured at 30 min, 60 min, 90 min, 120 min, 180 min and 240 min, and the results are shown in Table 3.

[0133] Table 3 demulsification results of experimental groups 12-15

[0134]

[0135] As shown in Table 3, the demulsifier provided by the application can achieve a demulsification efficiency of 96.57% at 45℃ for 180 min, and a demulsification efficiency of 100% at 50℃ and 55℃ for 120 min.

[0136] Therefore, the preparation process of the demulsifier is simple, the demulsification temperature is low, the demulsification efficiency is high, and the demulsification rate is fast. The demulsifier is a new type of amphiphilic surfactant, which can change the wettability, surface tension and surface tension of water. The project intends to use chemical demulsification technology to speed up the demulsification speed and improve the demulsification efficiency. Compared with conventional demulsifiers, the surface activity of the demulsifier is significantly improved. By using two long carbon chains and a hydrophilic center, the dispersion ability in the W / O emulsion system is improved, and the interaction with natural interfacial active substances is enhanced, thereby breaking the asphaltene interface layer and accelerating demulsification.

[0137] The preparation process of the method is simple and easy to implement. The demulsifier can quickly demulsify stable oil-water emulsion, and the demulsification effect is obvious, and the separated water phase is clear.

[0138] It should be noted that the present application is not limited to the above-mentioned embodiments. The above-mentioned embodiments are only examples, and embodiments having the same technical idea and playing the same role within the scope of the technical solution of the present application are included in the technical scope of the present application. In addition, within the scope of the main idea of the present application, various modifications of the embodiments that can be thought of by those skilled in the art, and other ways constructed by combining part of the constituent elements of the embodiments are also included in the scope of the present application.

Claims

1. A process for the preparation of a low temperature demulsifier, characterized in that, The method comprises the following steps: Ethylene amine compound and alkyl acrylate are used as raw materials, mixed in a first solvent, and reacted, the molar ratio of the ethylene amine compound and the alkyl acrylate is 1:(1-4), after the reaction is completed, the excess solvent is spin-evaporated, and a low-temperature demulsifier is obtained; The ethylene amine compound is selected from one of polyethylene polyamine, tetraethylene pentamine and pentaethylene hexamine; The alkyl acrylate is selected from dodecyl acrylate; The first solvent is selected from xylene.

2. The method of claim 1, wherein the low temperature demulsifier is prepared by the steps of: The reaction temperature is 60-80 DEG C, and the reaction time is 22-24 h.

3. Use of a low temperature demulsifier according to claim 1 or 2 for breaking emulsions of crude oil, characterized in that, The method comprises the following steps: dispersing the demulsifier in a second solvent to obtain a mixed solution; mixing the mixed solution with a crude oil emulsion uniformly, heating to 50-60 DEG C, and then standing for 0.5-2.5 h, so that the demulsification of the crude oil emulsion is completed.

4. Use of the cryogenic demulsifier according to claim 3 for breaking emulsions of crude oil, characterized in that, The second solvent is selected from one or more of water, ethanol and xylene.

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