Y-type ionic liquid demulsifier as well as preparation method and application thereof

Abstract

The invention discloses a Y-type ionic liquid demulsifier as well as a preparation method and application thereof. The preparation method comprises the following steps: (1) carrying out Mannich reaction on alkylphenol, formaldehyde and dimethylamine to obtain tertiary amine modified alkylphenol; (2) reacting the tertiary amine modified alkylphenol with epoxy chloropropane to obtain epoxy ammonium chloride modified alkylphenol; (3) reacting the epoxy ammonium chloride modified alkylphenol with alkylaniline to obtain a Y-type ionic liquid demulsifier; the molecular structure of the Y-type ionic liquid demulsifier provided by the invention has a plurality of benzene ring structures and a plurality of hydrophobic chains, shows amphipathy, can occupy a larger area on an oil-water interface, and has higher interfacial activity. The Y-type ionic liquid demulsifier provided by the invention has relatively strong competitive adsorption capacity, can be quickly diffused to an oil-water interface and react with interface active substances and the like, replaces original active substances on an interface film, reduces the stability of the interface film and induces demulsification.

Description

Technical Field

[0001] The invention belongs to the technical field of oilfield chemical additives, and particularly relates to an ionic liquid demulsifier and a preparation method and application thereof. Background Art

[0002] Most oil fields in my country have entered the tertiary oil recovery (TER) phase. The addition of chemical agents such as polymers, alkali, and surfactants during the recovery process further complicates the crude oil composition, increasing its water content and the difficulty of demulsification. This leads to higher dehydration costs and energy waste. Crude oil rich in colloids and asphaltene, in particular, exhibits high viscosity, a small oil-water density difference, and poor fluidity. The resulting multiple emulsions are very stable, resulting in high demulsification temperatures and high chemical dosages. Natural surfactants such as colloids and asphaltene in crude oil adsorb at the oil-water interface, forming a strong interfacial film that complicates oil-water separation.

[0003] Currently, the demulsifiers used domestically are primarily polyoxyethylene-polyoxypropylene block copolymers (PEBCOs), modified through methods such as head modification, tail replacement, backbone addition, grafting, chain extension, and compounding. However, these demulsifiers, when used on-site, suffer from issues such as high specificity, high dosage, slow dehydration, high oil content in wastewater, high water content in purified oil, or the presence of intermediate layers. This increases investment costs and still fails to achieve ideal demulsification results.

[0004] Because crude oil rich in colloids and asphaltene has high viscosity, low oil-water density, and excessively high levels of active components, demulsifiers have poor permeability, slow diffusion and droplet aggregation, resulting in high demulsifier dosages, slow demulsification, and poor demulsification effectiveness. Therefore, there is an urgent need to develop a new, more effective demulsifier for crude oil rich in colloids and asphaltene. Summary of the Invention

[0005] To address the problems of high viscosity, low oil-water density, and excessively high active components in crude oil rich in colloids and asphaltene, the present invention provides a Y-type ionic liquid demulsifier. The Y-type ionic liquid demulsifier has good low-temperature demulsification ability for crude oil rich in colloids and asphaltene, requires low demulsifier dosage, has a short demulsification time, and has high demulsification efficiency.

[0006] A Y-type ionic liquid demulsifier has the following molecular structure:

[0007] Among them, R1 and R2 are C n H 2n+1 , n is an integer between 8 and 18.

[0008] The present invention also provides a preparation method and application of the Y-type ionic liquid demulsifier.

[0009] The preparation method of the above-mentioned Y-type ionic liquid demulsifier comprises the following steps: (1) Tertiary amine-modified alkylphenols are obtained by the Mannich reaction of alkylphenols with formaldehyde and dimethylamine; (2) Tertiary amine-modified alkylphenol reacts with epichlorohydrin to obtain epoxyammonium chloride-modified alkylphenol; (3) Epoxyammonium chloride-modified alkylphenol reacts with alkylaniline to obtain a Y-type ionic liquid demulsifier.

[0010] In the above scheme, the alkylphenol in step (1) is one of 4-octylphenol, 4-dodecylphenol, 4-tetradecylphenol, 4-hexadecylphenol, and 4-octadecylphenol, or any mixture thereof; the formaldehyde is a 37-40% formaldehyde aqueous solution, and the dimethylamine is a 40% dimethylamine aqueous solution.

[0011] In the above scheme, the molar ratio of alkylphenol, formaldehyde and dimethylamine in step (1) is 1:(2-3):(2-3).

[0012] In the above scheme, the reaction temperature in step (1) is 40-100°C and the reaction time is 2-5h.

[0013] In the above scheme, the molar ratio of the tertiary amine-modified alkylphenol to epichlorohydrin in step (2) is 1:(3-5).

[0014] In the above scheme, the reaction temperature in step (2) is 40-100°C and the reaction time is 2-5h.

[0015] In the above scheme, the alkylaniline in step (3) is one of 4-octylaniline, 4-dodecylaniline, 4-tetradecylaniline, 4-hexadecylaniline, and 4-octadecylaniline, or any mixture thereof.

[0016] In the above scheme, the molar ratio of the epoxyammonium chloride-modified alkylphenol and the alkylaniline in step (3) is 1:2.

[0017] In the above scheme, the reaction temperature in step (3) is 40-100°C and the reaction time is 2-5h.

[0018] Application of the above-mentioned Y-type ionic liquid demulsifier in demulsification of crude oil emulsion.

[0019] In the above scheme, the concentration of the Y-type ionic liquid demulsifier in the crude oil emulsion is 50-300 mg / L; the demulsification temperature is 50-70° C., and the demulsification time is 1-3 hours.

[0020] Compared with the prior art, the present invention has the following beneficial effects: The Y-type ionic liquid demulsifier provided by the present invention has multiple benzene ring structures and multiple hydrophobic chains in its molecular structure, and can interact with surface active substances through π-π interaction and hydrophobic interaction.

[0021] The Y-type ionic liquid demulsifier provided by the present invention has two quaternary ammonium salt structures in its molecular structure. The zeta potential of the demulsifier molecule is positive, which can generate electrostatic neutralization with the negatively charged interfacial active substance, thereby reducing the stability of the dispersed phase.

[0022] The Y-type ionic liquid demulsifier provided by the present invention exhibits amphiphilicity, can occupy a larger area at the oil-water interface, and has high interfacial activity.

[0023] The Y-type ionic liquid demulsifier provided by the present invention has strong competitive adsorption ability, can quickly diffuse to the oil-water interface and interact with interfacial active substances, etc., replace the original active substances on the interfacial film, reduce the stability of the interfacial film, and induce demulsification. DETAILED DESCRIPTION

[0024] In order to better understand the present invention, the content of the present invention is further illustrated below in conjunction with the examples, but the content of the present invention is not limited to the following examples.

[0025] The specific embodiment provides a method for preparing a Y-type ionic liquid demulsifier, comprising the following steps: S1, obtaining a tertiary amine-modified alkylphenol by a Mannich reaction of an alkylphenol with formaldehyde and dimethylamine, the structural formula of which is shown below; the molar ratio of the alkylphenol, formaldehyde and dimethylamine is 1:(2-3):(2-3); the reaction temperature is 40-100°C, and the reaction time is 2-5 hours;

[0026] Where R1 is C n H 2n+1 , n is an integer between 8 and 18; S2, reacting a tertiary amine-modified alkylphenol with epichlorohydrin to obtain an epoxyammonium chloride-modified alkylphenol, the structural formula of which is shown below; the molar ratio of the tertiary amine-modified alkylphenol to epichlorohydrin is 1:(3-5); the reaction temperature is 40-100°C, and the reaction time is 2-5 hours;

[0027] Where R1 is C n H 2n+1 , n is an integer between 8 and 18; S3, epoxy ammonium chloride modified alkyl phenol reacts with alkyl aniline to obtain a Y-type ionic liquid demulsifier, the structural formula of which is shown below; the molar ratio of epoxy ammonium chloride modified alkyl phenol to alkyl aniline is 1:2; the reaction temperature is 40-100° C., and the reaction time is 2-5 hours;

[0028] In the formula, R1 and R2 are C n H 2n+1 , n is an integer between 8 and 18.

[0029] Specifically, the alkylphenol is one of 4-octylphenol, 4-dodecylphenol, 4-tetradecylphenol, 4-hexadecylphenol, and 4-octadecylphenol, or any mixture thereof. The alkylaniline is one of 4-octylaniline, 4-dodecylaniline, 4-tetradecylaniline, 4-hexadecylaniline, and 4-octadecylaniline, or any mixture thereof. Unless otherwise specified, the raw materials used in the specific embodiment are all commercially available.

[0030] The specific embodiment also provides a crude oil emulsion demulsification method, wherein the Y-type ionic liquid demulsifier is added to the crude oil emulsion at a concentration of 50-300 mg / L; the demulsification temperature is 50-70° C., and the demulsification time is 1-3 hours.

[0031] Example 1 A Y-type ionic liquid demulsifier, its molecular structure is: , Wherein, R1, R2 are C 12 H 25 .

[0032] The preparation method of the above-mentioned Y-type ionic liquid demulsifier comprises the following steps: 1) Dissolve 0.1 mol of 4-dodecylphenol in 50 ml of methanol, then add 0.21 mol of dimethylamine and mix thoroughly. Then, add 0.21 mol of formaldehyde dropwise and keep at 50°C for 2 hours. Then, reflux for 5 hours to remove the solvent and impurities to obtain tertiary amine-modified alkylphenol. 2) Dissolve 0.1 mol of tertiary amine-modified alkylphenol in 50 ml of methanol, then add 0.2 mol of epichlorohydrin dropwise. After the addition is complete, react at 60°C for 8 hours to obtain epoxyammonium chloride-modified alkylphenol; 3) Dissolve 0.1 mol of epoxyammonium chloride-modified alkylphenol in 50 ml of xylene, then add 0.2 mol of 4-dodecylaniline, mix well, and heat to 100 degrees Celsius to react for 5 hours to obtain a Y-type ionic liquid demulsifier.

[0033] Example 2 A Y-type ionic liquid demulsifier, its molecular structure is: , Wherein, R1, R2 are C 14 H 29 .

[0034] The preparation method of the above-mentioned Y-type ionic liquid demulsifier comprises the following steps: 1) Dissolve 0.1 mol of 4-tetradecylphenol in 50 ml of methanol, then add 0.21 mol of dimethylamine and mix thoroughly. Then, add 0.21 mol of formaldehyde dropwise and keep at 50°C for 2 hours. Then, reflux for 5 hours to remove the solvent and impurities to obtain tertiary amine-modified alkylphenol. 2) Dissolve 0.1 mol of tertiary amine-modified alkylphenol in 50 ml of methanol, then add 0.2 mol of epichlorohydrin dropwise. After the addition is complete, react at 60°C for 8 hours to obtain epoxyammonium chloride-modified alkylphenol; 3) Dissolve 0.1 mol of epoxyammonium chloride-modified alkylphenol in 50 ml of xylene, then add 0.2 mol of 4-tetradecylaniline, mix well, and heat to 100 degrees Celsius to react for 5 hours to obtain a Y-type ionic liquid demulsifier.

[0035] Example 3 A Y-type ionic liquid demulsifier, its molecular structure is: , Wherein, R1, R2 are C 16 H 33 .

[0036] The preparation method of the above-mentioned Y-type ionic liquid demulsifier comprises the following steps: 1) Dissolve 0.1 mol of 4-hexadecylphenol in 50 ml of methanol, then add 0.21 mol of dimethylamine and mix thoroughly. Then, add 0.21 mol of formaldehyde dropwise and keep at 50°C for 2 hours. Then, reflux for 5 hours to remove the solvent and impurities to obtain tertiary amine-modified alkylphenol. 2) Dissolve 0.1 mol of tertiary amine-modified alkylphenol in 50 ml of methanol, then add 0.2 mol of epichlorohydrin dropwise. After the addition is complete, react at 60°C for 8 hours to obtain epoxyammonium chloride-modified alkylphenol; 3) Dissolve 0.1 mol of epoxyammonium chloride-modified alkylphenol in 50 ml of xylene, then add 0.2 mol of 4-hexadecylaniline, mix well, and heat to 100 degrees Celsius to react for 5 hours to obtain a Y-type ionic liquid demulsifier.

[0037] Example 4 A Y-type ionic liquid demulsifier, its molecular structure is: , Wherein, R1 and R2 are C8H 17 .

[0038] The preparation method of the above-mentioned Y-type ionic liquid demulsifier comprises the following steps: 1) Dissolve 0.1 mol of 4-octylphenol in 50 ml of methanol, then add 0.21 mol of dimethylamine and mix thoroughly. Then, add 0.21 mol of formaldehyde dropwise and keep at 50°C for 2 hours. Then, reflux for 5 hours to remove the solvent and impurities to obtain tertiary amine-modified alkylphenol. 2) Dissolve 0.1 mol of tertiary amine-modified alkylphenol in 50 ml of methanol, then add 0.2 mol of epichlorohydrin dropwise. After the addition is complete, react at 60°C for 8 hours to obtain epoxyammonium chloride-modified alkylphenol; 3) Dissolve 0.1 mol of epoxyammonium chloride-modified alkylphenol in 50 ml of xylene, then add 0.2 mol of 4-octylaniline, mix well, and heat to 100 degrees Celsius to react for 5 hours to obtain a Y-type ionic liquid demulsifier.

[0039] Application Example 1 150 parts by weight of crude oil (source: Changqing Oilfield, viscosity at 25°C: 7.6 mPa·s, asphaltene: 14 wt %, resin: 6.03 wt %, wax: 15.46%, water: 1.6 wt %) was added to 350 parts by weight of water, heated to 60°C, and stirred at 11,000 rpm for 20 minutes to obtain a stable crude oil emulsion.

[0040] The Y-type ionic liquid demulsifier in Example 1-4 was dissolved in ethanol to obtain a 0.4% mass fraction demulsifier solution; then 1 part by volume of the demulsifier solution was added to 20 parts by volume of the crude oil emulsion and thoroughly shaken to mix evenly. The mixture was allowed to stand in a 50°C water bath for 2 hours, and the dehydration rate was measured to characterize the demulsification efficiency. The results are shown in Table 1.

[0041] Table 1

[0042] It can be seen from Table 1 that the Y-type ionic liquid demulsifiers in Examples 1-4 have excellent demulsification performance.

[0043] Application Example 2 150 parts by weight of crude oil (source: Changqing Oilfield, viscosity at 25°C: 7.6 mPa·s, asphaltene: 14 wt %, resin: 6.03 wt %, wax: 15.46%, water: 1.6 wt %) was added to 350 parts by weight of water, heated to 60°C, and stirred at 11,000 rpm for 20 minutes to obtain a stable crude oil emulsion.

[0044] Four parts of the Y-type ionic liquid demulsifier in Example 1 were dissolved in ethanol to prepare demulsifier solutions with mass fractions of 0.5%, 0.4%, 0.3%, 0.2%, and 0.1%, respectively. Then, 1 part by volume of the demulsifier solutions with different mass fractions was added to 20 parts by volume of the crude oil emulsion and thoroughly shaken to mix. The mixture was allowed to stand in a 50°C water bath for 2 hours, and the dehydration rate was measured to characterize the demulsification efficiency. The results are shown in Table 2.

[0045] Table 2

[0046] As can be seen from Table 2, when the concentration of the Y-type ionic liquid demulsifier of the present invention in the crude oil emulsion is 50-250 mg / L, a relatively high demulsification efficiency can be achieved.

[0047] Application Example 3 150 parts by weight of crude oil (source: Changqing Oilfield, viscosity at 25°C: 7.6 mPa·s, asphaltene: 14 wt %, resin: 6.03 wt %, wax: 15.46%, water: 1.6 wt %) was added to 350 parts by weight of water, heated to 60°C, and stirred at 11,000 rpm for 20 minutes to obtain a stable crude oil emulsion.

[0048] The Y-type ionic liquid demulsifier in Example 1 was dissolved in ethanol to obtain a 0.4% mass fraction demulsifier solution; the demulsifier solution was divided into four parts, each of which was thoroughly shaken and mixed with 20 times the volume of crude oil emulsion, and then allowed to stand in water baths at 40°C, 50°C, 60°C, and 70°C for 2 hours, respectively. The dehydration rate was measured to characterize the demulsification efficiency. The results are shown in Table 3.

[0049] Table 3

[0050] It can be seen from Table 3 that the Y-type ionic liquid demulsifier of the present invention can achieve a high demulsification efficiency under low temperature conditions of 50-70°C.

[0051] In summary, the Y-type ionic liquid demulsifier of the invention has the characteristics of good low-temperature demulsification ability, low demulsifier dosage, short demulsification time, and high demulsification efficiency.

[0052] The above embodiments are merely examples for clarification and are not intended to limit the implementation methods. Those skilled in the art will appreciate that other variations or modifications may be made based on the above descriptions. It is not necessary and impossible to enumerate all implementation methods here, and any obvious variations or modifications derived therefrom are still within the scope of protection of the present invention.

Claims

1. A Y-type ionic liquid demulsifier, characterized in that It has the following molecular structure: Among them, R1 and R2 are C n H 2n+1 , n is an integer between 8 and 18.

2. The preparation method of the Y-type ionic liquid demulsifier according to claim 1, characterized in that The following steps are involved: (1) Tertiary amine-modified alkylphenols are obtained by the Mannich reaction of alkylphenols with formaldehyde and dimethylamine; (2) Tertiary amine-modified alkylphenol reacts with epichlorohydrin to obtain epoxyammonium chloride-modified alkylphenol; (3) Epoxyammonium chloride-modified alkylphenol reacts with alkylaniline to obtain a Y-type ionic liquid demulsifier.

3. The preparation method of the Y-type ionic liquid demulsifier according to claim 2, characterized in that The alkylphenol in step (1) is one of 4-octylphenol, 4-dodecylphenol, 4-tetradecylphenol, 4-hexadecylphenol, and 4-octadecylphenol, or any mixture thereof.

4. The preparation method of the Y-type ionic liquid demulsifier according to claim 2, characterized in that The molar ratio of the alkylphenol, formaldehyde and dimethylamine in step (1) is 1:(2-3):(2-3).

5. The preparation method of the Y-type ionic liquid demulsifier according to claim 2, characterized in that In step (1), the reaction temperature is 40-100° C. and the reaction time is 2-5 h.

6. The preparation method of the Y-type ionic liquid demulsifier according to claim 2, characterized in that In step (2), the molar ratio of the tertiary amine-modified alkylphenol to epichlorohydrin is 1:(3-5); the reaction temperature is 40-100° C., and the reaction time is 2-5 h.

7. The preparation method of the Y-type ionic liquid demulsifier according to claim 2, characterized in that The alkylaniline in step (3) is one of 4-octylaniline, 4-dodecylaniline, 4-tetradecylaniline, 4-hexadecylaniline, and 4-octadecylaniline, or any mixture thereof.

8. The preparation method of the Y-type ionic liquid demulsifier according to claim 2, characterized in that The molar ratio of the epoxyammonium chloride-modified alkylphenol and the alkylaniline in step (3) is 1:

2.

9. The preparation method of the Y-type ionic liquid demulsifier according to claim 2, characterized in that In step (3), the reaction temperature is 40-100°C and the reaction time is 2-5h.

10. Use of the Y-type ionic liquid demulsifier according to claim 1 in demulsifying crude oil emulsions, characterized in that The concentration of the Y-type ionic liquid demulsifier in the crude oil emulsion is 50-300 mg / L; the demulsification temperature is 50-70° C.; and the demulsification time is 1-3 hours.

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