A crude oil desalting agent and preparation method thereof

Abstract

The invention relates to the technical field of desalting agents, and discloses a crude oil desalting agent and a preparation method thereof. The invention obtains a crude oil desalting agent by adding melamine-modified multi-branched polyether, quaternized carboxyl chitosan-modified polyacrylate emulsion, and graphene oxide into a reactor for stirring. The silicon-oxygen bond in the melamine-modified multi-branched polyether improves the high temperature resistance of the desalting agent; the triazine ring structure of melamine has good thermal stability; the positive charge of the quaternary ammonium salt can neutralize the negative charge on the surface of the oil droplet, thereby improving the desalting performance of the desalting agent; the multi-branched polyether has a better desalting effect than the linear polyether; the quaternary ammonium salt group is grafted on the carboxymethyl chitosan, so that the chitosan carries both positive and negative charges, which can not only adsorb metal cations in crude oil, but also combine with negatively charged ions such as cyclopentane acid radicals, thereby improving the desalting performance; the conjugated effect formed by the double benzene ring structure of the naphthyl group improves the high temperature resistance of the desalting agent.

Description

Technical Field

[0001] The invention relates to the technical field of desalting agents, in particular to a crude oil desalting agent and a preparation method thereof. Background Art

[0002] With the continuous development of crude oil in oil fields, the requirements for deep desalting of crude oil are getting higher and higher. Most of the salts in crude oil are water-soluble inorganic salts, such as calcium chloride, sodium chloride, etc. Most of these salts are dissolved in the water contained in crude oil and exist in the crude oil in the form of emulsions; in addition, a small number of trace metals exist in the form of oil-soluble organic acid salts, which are difficult to remove from crude oil. Before crude oil enters the atmospheric and vacuum distillation unit for distillation, it must first be deeply desalted and dehydrated to eliminate the various adverse effects of the presence of water and salts on the subsequent processing process. The key to crude oil desalting is dehydration, and the key to dehydration is demulsification. At present, the crude oil desalting technology is mainly based on electrochemical desalting and dehydration. Under the joint action of desalting demulsifier and electric field, the crude oil emulsion is separated into oil and water, so that the crude oil is dehydrated and desalted. In the process of crude oil dehydration and desalting, the high temperature environment may destroy the stability and effectiveness of the desalting demulsifier and affect the desalting effect. In the document "Research and Development of High-efficiency Crude Oil Demulsification Desalter NS-80", the NS-80 high-efficiency demulsification desalter with better dehydration and desalting effects was screened out. This desalter has low cost and good benefits, but its high temperature resistance still needs to be improved. Summary of the invention

[0003] 1. Technical issues to be resolved

[0004] In view of the shortcomings of the prior art, the present invention provides a crude oil desalter and a preparation method thereof. The crude oil desalter prepared by the present invention improves the high temperature resistance of the desalter and has a good desalting effect on crude oil.

[0005] (II) Technical solution

[0006] To achieve the above object, the present invention provides the following technical solution: a crude oil desalter, comprising the following weight components: 16-20 parts by weight of melamine-modified multi-branched polyether, 24-28 parts by weight of quaternized carboxyl chitosan-modified polyacrylate emulsion, and 5-9 parts by weight of graphene oxide;

[0007] Preferably, the preparation method of the melamine-modified multi-branched polyether comprises the following steps:

[0008] (1) Add dibutylcarbamoyl chloride to anhydrous ethanol solvent, stir to dissolve, introduce nitrogen protection, heat to 80-85° C., add 1,3-dichlorotetraphenyldisiloxane, reflux for 4-8 hours, cool after the reaction, wash and dry to obtain acyl chloride silane gemini quaternary ammonium salt;

[0009] (2) Add 25-30 g of melamine to the n-hexane solution, stir to dissolve, add 6-9 g of acyl chloride silane gemini quaternary ammonium salt dropwise thereto, react at 20-25° C. for 1-3 h, and after the reaction is completed, stand to separate the precipitates, wash with deionized water, filter and dry to obtain a quaternary ammonium salt modified melamine initiator;

[0010] (3) Add 8-12 g of quaternary ammonium salt modified melamine initiator, 16-24 g of propylene oxide, and 0.06-0.09 g of potassium hydroxide catalyst to a high-pressure reactor, seal the reactor, purge with nitrogen for 3-5 minutes, heat to 140-150° C., react for 1-1.5 hours, cool to room temperature, add 12-15 g of ethylene oxide, heat to 120-135° C., continue to react for 2-3 hours, and after the reaction is completed, add 0.05-0.08 g of glacial acetic acid to neutralize the potassium hydroxide catalyst to obtain a melamine-modified multi-branched polyether;

[0011] Preferably, the method for preparing the quaternized carboxyl chitosan modified polyacrylate emulsion comprises the following steps:

[0012] S1. Add 4-8 g of N-(1-naphthyl)-N-phenylmethyl acrylamide and 15-22 g of epichlorohydrin to the reactor, stir and mix, react at 24-30 ° C for 12-15 h, and after the reaction, extract and freeze-dry to obtain a naphthyl quaternary ammonium salt;

[0013] S2. 6-9 g of carboxyl chitosan was added to deionized water, stirred to dissolve, 18-26 g of naphthyl quaternary ammonium salt was dissolved in deionized water, and then added dropwise to the carboxyl chitosan solution for 30-45 min, 0.02-0.05 g of potassium hydroxide was added to adjust the pH so that the pH value was maintained at 8-9 during the reaction, the temperature was raised to 75-85 ° C, the reaction was continued for 7-10 h, and after the reaction was completed, the mixture was cooled, dialyzed, and freeze-dried to obtain quaternized carboxyl chitosan;

[0014] S3. 0.05-0.08 g of sodium dodecyl sulfate emulsifier was added to deionized water, stirred and heated to the reaction temperature, nitrogen was introduced for 30-40 min to remove oxygen, 0.06-0.09 g of ammonium persulfate initiator was added, stirred for 10-15 min, 7-10 g of ethyl methacrylate, 1-4 g of methacrylic acid, 4-6 g of quaternized carboxyl chitosan were added thereto, and the reaction was kept warm for 30-50 min, and then 0.03-0.05 g of ammonium persulfate initiator was added, and the reaction was kept warm for 20-40 min. After the reaction, a quaternized carboxyl chitosan modified polyacrylate emulsion was obtained;

[0015] Preferably, in step (1), the mass ratio of dibutylcarbamoyl chloride to 1,3-dichlorotetraphenyldisiloxane is 1:1.1-1.15.

[0016] Preferably, the dripping time of the acyl chloride silane gemini quaternary ammonium salt in step (2) is controlled within 50-80 min.

[0017] Preferably, the preparation method of the carboxyl chitosan in S2 is: add 10-12g of chitosan to an acetic acid solution with a mass fraction of 1%-1.4%, stir to dissolve, add 12-15g of hydrated glyoxylic acid, react at 28-32°C for 3-6h, add 0.03-0.07g of sodium hydroxide to adjust the pH value to 4-5, add 3-6g of sodium borohydride solution with a mass fraction of 4.2%-4.8% to reduce for 10-15min, add anhydrous ethanol to precipitate, filter, and freeze-dry to obtain carboxyl chitosan.

[0018] Preferably, the reaction temperature in S3 is 72-80°C.

[0019] Preferably, the preparation method of the crude oil desalter is: adding melamine-modified multi-branched polyether, quaternized carboxyl chitosan-modified polyacrylate emulsion, and graphene oxide into a reactor, stirring at 800-1400 rpm for 12-20 min, to obtain the crude oil desalter.

[0020] 3. Beneficial technical effects

[0021] The invention obtains a crude oil desalting agent by adding melamine-modified multi-branched polyether, quaternized carboxyl chitosan-modified polyacrylate emulsion and graphene oxide into a reactor and stirring.

[0022] The tertiary amine group in dibutylcarbamoyl chloride undergoes a quaternization reaction with 1,3-dichlorotetraphenyldisiloxane to obtain an acyl chloride silane gemini quaternary ammonium salt, the acyl chloride group in the acyl chloride silane gemini quaternary ammonium salt undergoes an amidation reaction with melamine to obtain a quaternary ammonium salt modified melamine initiator, and the primary amine and secondary amine groups in the quaternary ammonium salt modified melamine initiator undergo a polymerization reaction with propylene oxide and ethylene oxide to obtain a melamine modified multi-branched polyether. The amino group in chitosan reacts with glyoxylic acid to obtain chitosan Schiff base, which is then reduced with sodium borohydride to obtain carboxyl chitosan. The tertiary amine group in N-(1-naphthyl)-N-phenylmethacrylamide reacts with epichlorohydrin to undergo quaternization reaction to obtain naphthyl quaternary ammonium salt. The epoxy group in the naphthyl quaternary ammonium salt reacts with the hydroxyl group in carboxyl chitosan to undergo ring-opening addition reaction to obtain quaternized carboxyl chitosan. Alkenyl groups are introduced, and the quaternized carboxyl chitosan is polymerized with ethyl methacrylate and methacrylic acid to obtain quaternized carboxyl chitosan modified polyacrylate emulsion.

[0023] The silane bond energy in the melamine-modified multi-branched polyether is high, and it has high stability at high temperatures, which can improve the high-temperature resistance of the desalter. The triazine ring structure of melamine gives it good thermal and chemical stability at high temperatures, which improves the high-temperature resistance of the desalter. The positive charge carried by the quaternary ammonium salt can neutralize the negative charge on the surface of the oil droplets, reduce the interaction between the oil droplets, thereby increasing the probability of collision and combination between the oil droplets, reducing the stability of the crude oil emulsion, and improving the demulsification and desalination performance of the desalter. Compared with linear polyethers, the melamine-modified multi-branched polyether with a multi-branched structure has better wettability and permeability, and can quickly reach the oil-water interface. It also occupies a large surface area on the interface, which enhances the demulsification and desalination effect. In the quaternized carboxyl chitosan modified polyacrylate emulsion, carboxymethyl chitosan has the ability to chelate metal ions. The effect of the quaternary ammonium salt group on the carboxymethyl chitosan is improved to improve the ability of the desalter to remove oil-soluble salts. The quaternary ammonium salt group is grafted on the carboxymethyl chitosan, so that the chitosan has both positive and negative charges, so that it can not only adsorb metal cations in crude oil, but also combine with negatively charged ions such as cyclopentane acid and negatively charged particles in crude oil, destroy the double electric layer structure of the oil-water interface film, reduce the stability of the interface film, and further improve the desalting performance of the desalter; the conjugated effect formed by the double benzene ring structure of the naphthyl group further improves the high temperature resistance of the desalter; the quaternary ammonium carboxyl chitosan is polymerized with ethyl methacrylate and methacrylic acid to obtain a polyacrylate emulsion with polar groups such as carboxyl and ester groups, so it has high amphiphilicity, can quickly reach the oil-water interface, adsorb on the oil-water interface, reduce the strength of the interface film, promote the aggregation and merging of oil droplets, and achieve the purpose of demulsification and dehydration and desalination. DETAILED DESCRIPTION Example 1

[0024] (1) Add dibutylcarbamoyl chloride to anhydrous ethanol solvent, stir to dissolve, introduce nitrogen protection, heat to 80° C., add 1,3-dichlorotetraphenyldisiloxane, wherein the mass ratio of dibutylcarbamoyl chloride to 1,3-dichlorotetraphenyldisiloxane is 1:1.1, reflux for 4 hours, and after the reaction is completed, cool, wash and dry to obtain acyl chloride silane gemini quaternary ammonium salt;

[0025] (2) Add 25 g of melamine to the n-hexane solution, stir to dissolve, add 6 g of acyl chloride silane gemini quaternary ammonium salt dropwise thereto, the dropping time is controlled within 50 min, react at 20 ° C for 1 h, after the reaction is completed, stand and separate, wash the precipitate with deionized water, filter and dry to obtain a quaternary ammonium salt modified melamine initiator;

[0026] (3) Add 8 g of quaternary ammonium salt modified melamine initiator, 16 g of propylene oxide, and 0.06 g of potassium hydroxide catalyst to a high-pressure reactor, seal the reactor, purge with nitrogen for 3 min, heat to 140 ° C, react for 1 h, cool to room temperature, add 12 g of ethylene oxide, heat to 120 ° C, continue to react for 2 h, and after the reaction is completed, add 0.05 g of glacial acetic acid to neutralize the potassium hydroxide catalyst to obtain melamine modified multi-branched polyether;

[0027] (4) Add 10 g of chitosan to a 1% acetic acid solution, stir to dissolve, add 12 g of hydrated glyoxylic acid, react at 28°C for 3 h, add 0.03 g of sodium hydroxide to adjust the pH value to 4, dropwise add 3 g of 4.2% sodium borohydride solution to reduce for 10 min, add anhydrous ethanol to precipitate, filter, and freeze-dry to obtain carboxyl chitosan;

[0028] (5) Add 4 g of N-(1-naphthyl)-N-phenylmethyl acrylamide and 15 g of epichlorohydrin into the reactor, stir and mix, and react at 24° C. for 12 h. After the reaction is completed, extract and freeze-dry to obtain a naphthyl quaternary ammonium salt;

[0029] (6) Add 6 g of carboxyl chitosan to deionized water and stir to dissolve. Dissolve 18 g of naphthyl quaternary ammonium salt in deionized water and then add it dropwise to the carboxyl chitosan solution for 30 min. Add 0.02 g of potassium hydroxide to adjust the pH so that the pH value is maintained at 8 during the reaction. Heat to 75 °C and react for 7 h. After the reaction is completed, cool and dialyze, and freeze-dry to obtain quaternized carboxyl chitosan.

[0030] (7) Add 0.05 g of sodium dodecyl sulfate emulsifier to deionized water, stir and heat to 72°C, introduce nitrogen for 30 min to remove oxygen, add 0.06 g of ammonium persulfate initiator, stir for 10 min, add 7 g of ethyl methacrylate, 1 g of methacrylic acid, and 4 g of quaternized carboxyl chitosan, keep the temperature for reaction for 30 min, then continue to add 0.03 g of ammonium persulfate initiator, continue to keep the temperature for reaction for 20 min, and after the reaction is completed, obtain quaternized carboxyl chitosan modified polyacrylate emulsion;

[0031] (8) 16 parts by weight of melamine-modified multi-branched polyether, 24 parts by weight of quaternized carboxyl chitosan-modified polyacrylate emulsion, and 5 parts by weight of graphene oxide were added into a reactor and stirred at 800 rpm for 12 min to obtain a crude oil desalter. Example 2

[0032] (1) Add dibutylcarbamoyl chloride to anhydrous ethanol solvent, stir to dissolve, introduce nitrogen protection, heat to 85° C., add 1,3-dichlorotetraphenyldisiloxane, wherein the mass ratio of dibutylcarbamoyl chloride to 1,3-dichlorotetraphenyldisiloxane is 1:1.15, reflux for 8 hours, and after the reaction is completed, cool, wash and dry to obtain acyl chloride silane gemini quaternary ammonium salt;

[0033] (2) Add 30 g of melamine to the n-hexane solution, stir to dissolve, add 9 g of acyl chloride silane gemini quaternary ammonium salt dropwise thereto, the dropping time is controlled to be 80 min, react at 25 ° C for 3 h, after the reaction is completed, stand and separate, wash the precipitate with deionized water, filter and dry to obtain a quaternary ammonium salt modified melamine initiator;

[0034] (3) Add 12 g of quaternary ammonium salt modified melamine initiator, 24 g of propylene oxide, and 0.09 g of potassium hydroxide catalyst to a high-pressure reactor, seal the reactor, purge with nitrogen for 5 min, heat to 150 ° C, react for 1.5 h, cool to room temperature, add 15 g of ethylene oxide, heat to 135 ° C, continue to react for 3 h, and after the reaction is completed, add 0.08 g of glacial acetic acid to neutralize the potassium hydroxide catalyst to obtain melamine modified multi-branched polyether;

[0035] (4) Add 12 g of chitosan to a 1.4% acetic acid solution, stir to dissolve, add 15 g of hydrated glyoxylic acid, react at 32°C for 6 h, add 0.07 g of sodium hydroxide to adjust the pH to 5, dropwise add 6 g of 4.8% sodium borohydride solution to reduce for 15 min, add anhydrous ethanol to precipitate, filter, and freeze-dry to obtain carboxyl chitosan;

[0036] (5) Add 8 g of N-(1-naphthyl)-N-phenylmethyl acrylamide and 22 g of epichlorohydrin into the reactor, stir and mix, react at 30° C. for 15 h, extract and freeze-dry after the reaction to obtain naphthyl quaternary ammonium salt;

[0037] (6) Add 9 g of carboxyl chitosan to deionized water and stir to dissolve. Dissolve 26 g of naphthyl quaternary ammonium salt in deionized water and then add it dropwise to the carboxyl chitosan solution for 45 min. Add 0.05 g of potassium hydroxide to adjust the pH so that the pH value is maintained at 9 during the reaction. Heat to 85 °C and react for 10 h. After the reaction is completed, cool and dialyze, and freeze-dry to obtain quaternized carboxyl chitosan.

[0038] (7) Add 0.08 g of sodium dodecyl sulfate emulsifier to deionized water, stir and heat to 80°C, introduce nitrogen for 40 min to remove oxygen, add 0.09 g of ammonium persulfate initiator, stir for 15 min, add 10 g of ethyl methacrylate, 4 g of methacrylic acid, and 6 g of quaternized carboxyl chitosan, keep the temperature for reaction for 50 min, then continue to add 0.05 g of ammonium persulfate initiator, continue to keep the temperature for reaction for 40 min, and after the reaction is completed, obtain quaternized carboxyl chitosan modified polyacrylate emulsion;

[0039] (8) 20 parts by weight of melamine-modified multi-branched polyether, 28 parts by weight of quaternized carboxyl chitosan-modified polyacrylate emulsion, and 9 parts by weight of graphene oxide were added into a reactor and stirred at 1400 rpm for 20 min to obtain a crude oil desalter. Example 3

[0040] (1) Add dibutylcarbamoyl chloride to anhydrous ethanol solvent, stir to dissolve, introduce nitrogen protection, heat to 82° C., add 1,3-dichlorotetraphenyldisiloxane, wherein the mass ratio of dibutylcarbamoyl chloride to 1,3-dichlorotetraphenyldisiloxane is 1:1.13, reflux for 6 hours, and after the reaction is completed, cool, wash and dry to obtain acyl chloride silane gemini quaternary ammonium salt;

[0041] (2) Add 27.5 g of melamine to the n-hexane solution, stir to dissolve, add 7.5 g of acyl chloride silane gemini quaternary ammonium salt dropwise thereto, the dropping time is controlled within 65 min, react at 23 ° C for 2 h, after the reaction is completed, stand and separate, wash the precipitate with deionized water, filter and dry to obtain a quaternary ammonium salt modified melamine initiator;

[0042] (3) Add 10 g of quaternary ammonium salt modified melamine initiator, 20 g of propylene oxide, and 0.07 g of potassium hydroxide catalyst to a high-pressure reactor, seal the reactor, purge with nitrogen for 4 min, heat to 145 ° C, react for 1.2 h, cool to room temperature, add 13.5 g of ethylene oxide, heat to 128 ° C, continue to react for 2.5 h, and after the reaction is completed, add 0.06 g of glacial acetic acid to neutralize the potassium hydroxide catalyst to obtain melamine modified multi-branched polyether;

[0043] (4) Add 11 g of chitosan to a 1.2% acetic acid solution, stir to dissolve, add 13.5 g of hydrated glyoxylic acid, react at 30°C for 4.5 h, add 0.05 g of sodium hydroxide to adjust the pH value to 4-5, dropwise add 4.5 g of 4.5% sodium borohydride solution to reduce for 12 min, add anhydrous ethanol to precipitate, filter, and freeze-dry to obtain carboxyl chitosan;

[0044] (5) Add 6 g of N-(1-naphthyl)-N-phenylmethyl acrylamide and 18.5 g of epichlorohydrin into the reactor, stir and mix, react at 27° C. for 14 h, extract and freeze-dry after the reaction to obtain naphthyl quaternary ammonium salt;

[0045] (6) Add 7.5 g of carboxyl chitosan to deionized water and stir to dissolve. Dissolve 22 g of naphthyl quaternary ammonium salt in deionized water and then add it dropwise to the carboxyl chitosan solution for 38 min. Add 0.03 g of potassium hydroxide to adjust the pH so that the pH value is maintained at 8.5 during the reaction. Heat to 80 °C and react for 8.5 h. After the reaction is completed, cool and dialyze, and freeze-dry to obtain quaternized carboxyl chitosan.

[0046] (7) Add 0.06 g of sodium dodecyl sulfate emulsifier to deionized water, stir and heat to 76 ° C, introduce nitrogen for 35 minutes to remove oxygen, add 0.08 g of ammonium persulfate initiator, stir for 12 minutes, add 8.5 g of ethyl methacrylate, 2.5 g of methacrylic acid, and 5 g of quaternized carboxyl chitosan, keep the temperature for reaction for 40 minutes, continue to add 0.04 g of ammonium persulfate initiator, continue to keep the temperature for reaction for 30 minutes, and after the reaction is completed, obtain quaternized carboxyl chitosan modified polyacrylate emulsion;

[0047] (8) 18 parts by weight of melamine-modified multi-branched polyether, 26 parts by weight of quaternized carboxyl chitosan-modified polyacrylate emulsion, and 7 parts by weight of graphene oxide were added into a reactor and stirred at 1100 rpm for 16 min to obtain a crude oil desalter. Example 4

[0048] (1) Add dibutylcarbamoyl chloride to anhydrous ethanol solvent, stir to dissolve, introduce nitrogen protection, heat to 80° C., add 1,3-dichlorotetraphenyldisiloxane, wherein the mass ratio of dibutylcarbamoyl chloride to 1,3-dichlorotetraphenyldisiloxane is 1:1.1, reflux for 4 hours, and after the reaction is completed, cool, wash and dry to obtain acyl chloride silane gemini quaternary ammonium salt;

[0049] (2) Add 25 g of melamine to the n-hexane solution, stir to dissolve, add 6 g of acyl chloride silane gemini quaternary ammonium salt dropwise thereto, the dropping time is controlled within 50 min, react at 20 ° C for 1 h, after the reaction is completed, stand and separate, wash the precipitate with deionized water, filter and dry to obtain a quaternary ammonium salt modified melamine initiator;

[0050] (3) Add 8 g of quaternary ammonium salt modified melamine initiator, 16 g of propylene oxide, and 0.06 g of potassium hydroxide catalyst to a high-pressure reactor, seal the reactor, purge with nitrogen for 3 min, heat to 140 ° C, react for 1 h, cool to room temperature, add 12 g of ethylene oxide, heat to 120 ° C, continue to react for 2 h, and after the reaction is completed, add 0.05 g of glacial acetic acid to neutralize the potassium hydroxide catalyst to obtain melamine modified multi-branched polyether;

[0051] (4) Add 12 g of chitosan to a 1.4% acetic acid solution, stir to dissolve, add 15 g of hydrated glyoxylic acid, react at 32°C for 6 h, add 0.07 g of sodium hydroxide to adjust the pH to 5, dropwise add 6 g of 4.8% sodium borohydride solution to reduce for 15 min, add anhydrous ethanol to precipitate, filter, and freeze-dry to obtain carboxyl chitosan;

[0052] (5) Add 8 g of N-(1-naphthyl)-N-phenylmethyl acrylamide and 22 g of epichlorohydrin into the reactor, stir and mix, react at 30° C. for 15 h, extract and freeze-dry after the reaction to obtain naphthyl quaternary ammonium salt;

[0053] (6) Add 9 g of carboxyl chitosan to deionized water and stir to dissolve. Dissolve 26 g of naphthyl quaternary ammonium salt in deionized water and then add it dropwise to the carboxyl chitosan solution for 45 min. Add 0.05 g of potassium hydroxide to adjust the pH so that the pH value is maintained at 9 during the reaction. Heat to 85 °C and react for 10 h. After the reaction is completed, cool and dialyze, and freeze-dry to obtain quaternized carboxyl chitosan.

[0054] (7) Add 0.06 g of sodium dodecyl sulfate emulsifier to deionized water, stir and heat to 76 ° C, introduce nitrogen for 35 minutes to remove oxygen, add 0.08 g of ammonium persulfate initiator, stir for 12 minutes, add 8.5 g of ethyl methacrylate, 2.5 g of methacrylic acid, and 5 g of quaternized carboxyl chitosan, keep the temperature for reaction for 40 minutes, continue to add 0.04 g of ammonium persulfate initiator, continue to keep the temperature for reaction for 30 minutes, and after the reaction is completed, obtain quaternized carboxyl chitosan modified polyacrylate emulsion;

[0055] (8) 18 parts by weight of melamine-modified multi-branched polyether, 26 parts by weight of quaternized carboxyl chitosan-modified polyacrylate emulsion, and 7 parts by weight of graphene oxide were added into a reactor and stirred at 1100 rpm for 16 min to obtain a crude oil desalter. Example 5

[0056] (1) Add dibutylcarbamoyl chloride to anhydrous ethanol solvent, stir to dissolve, introduce nitrogen protection, heat to 82° C., add 1,3-dichlorotetraphenyldisiloxane, wherein the mass ratio of dibutylcarbamoyl chloride to 1,3-dichlorotetraphenyldisiloxane is 1:1.13, reflux for 6 hours, and after the reaction is completed, cool, wash and dry to obtain acyl chloride silane gemini quaternary ammonium salt;

[0057] (2) Add 27.5 g of melamine to the n-hexane solution, stir to dissolve, add 7.5 g of acyl chloride silane gemini quaternary ammonium salt dropwise thereto, the dropping time is controlled within 65 min, react at 23 ° C for 2 h, after the reaction is completed, stand and separate, wash the precipitate with deionized water, filter and dry to obtain a quaternary ammonium salt modified melamine initiator;

[0058] (3) Add 10 g of quaternary ammonium salt modified melamine initiator, 20 g of propylene oxide, and 0.07 g of potassium hydroxide catalyst to a high-pressure reactor, seal the reactor, purge with nitrogen for 4 min, heat to 145 ° C, react for 1.2 h, cool to room temperature, add 13.5 g of ethylene oxide, heat to 128 ° C, continue to react for 2.5 h, and after the reaction is completed, add 0.06 g of glacial acetic acid to neutralize the potassium hydroxide catalyst to obtain melamine modified multi-branched polyether;

[0059] (4) Add 10 g of chitosan to a 1% acetic acid solution, stir to dissolve, add 12 g of hydrated glyoxylic acid, react at 28°C for 3 h, add 0.03 g of sodium hydroxide to adjust the pH value to 4, dropwise add 3 g of 4.2% sodium borohydride solution to reduce for 10 min, add anhydrous ethanol to precipitate, filter, and freeze-dry to obtain carboxyl chitosan;

[0060] (5) Add 4 g of N-(1-naphthyl)-N-phenylmethyl acrylamide and 15 g of epichlorohydrin into the reactor, stir and mix, and react at 24° C. for 12 h. After the reaction is completed, extract and freeze-dry to obtain a naphthyl quaternary ammonium salt;

[0061] (6) Add 6 g of carboxyl chitosan to deionized water and stir to dissolve. Dissolve 18 g of naphthyl quaternary ammonium salt in deionized water and then add it dropwise to the carboxyl chitosan solution for 30 min. Add 0.02 g of potassium hydroxide to adjust the pH so that the pH value is maintained at 8 during the reaction. Heat to 75 °C and react for 7 h. After the reaction is completed, cool and dialyze, and freeze-dry to obtain quaternized carboxyl chitosan.

[0062] (7) Add 0.08 g of sodium dodecyl sulfate emulsifier to deionized water, stir and heat to 80°C, introduce nitrogen for 40 min to remove oxygen, add 0.09 g of ammonium persulfate initiator, stir for 15 min, add 10 g of ethyl methacrylate, 4 g of methacrylic acid, and 6 g of quaternized carboxyl chitosan, keep the temperature for reaction for 50 min, then continue to add 0.05 g of ammonium persulfate initiator, continue to keep the temperature for reaction for 40 min, and after the reaction is completed, obtain quaternized carboxyl chitosan modified polyacrylate emulsion;

[0063] (8) 20 parts by weight of melamine-modified multi-branched polyether, 28 parts by weight of quaternized carboxyl chitosan-modified polyacrylate emulsion, and 9 parts by weight of graphene oxide were added into a reactor and stirred at 1400 rpm for 20 min to obtain a crude oil desalter.

[0064] Comparative Example 1

[0065] Compared with Example 5, this comparative example is different in that no melamine-modified multi-branched polyether is added.

[0066] Comparative Example 2

[0067] Compared with Example 5, this comparative example is different in that no quaternary ammonium carboxyl chitosan modified polyacrylate emulsion is added.

[0068] The high temperature resistance of the crude oil desalter was tested by a thermogravimetric analyzer under the following conditions: under nitrogen, the heating rate was 10°C / min, and the test range was 50-300°C. The test results are shown in Table 1.

[0069] Table 1: High temperature resistance test.

[0070] project 200℃ mass loss rate (%) 300℃ mass loss rate (%) Example 1 4.8 19.6 Example 2 4.6 17.2 Example 3 5.2 18.7 Example 4 5.4 16.8 Example 5 4.5 18.1 Comparative Example 1 18.3 38.3 Comparative Example 2 15.7 46.4

[0071] It can be seen from Table 1 that the crude oil desalter in Examples 1-5 has better high temperature resistance than the crude oil desalter in Comparative Examples 1-2.

[0072] 80g crude oil was added to 20mL water, placed in a 75℃ water bath, and stirred at 8000rpm for 5min to obtain a crude oil emulsion. 3mL of a 1% crude oil desalter was added to the crude oil emulsion. The oil was desalted for 30min at an electric field strength of 800V / cm and a desalting temperature of 120℃. After oil and water separation, the salt content and water content in the crude oil were sampled and analyzed. The crude oil was taken from Gudao Oil Production Plant. The test results are shown in Table 2.

[0073] Table 2: Desalination performance test.

[0074] project Salt content (mg / L) Water content (%) Example 1 2.4 0.07 Example 2 2.2 0.04 Example 3 2.5 0.08 Example 4 1.9 0.05 Example 5 2.2 0.03 Comparative Example 1 8.5 0.35 Comparative Example 2 9.7 0.42

[0075] It can be seen from Table 2 that the crude oil desalter in Examples 1-5 has a better dehydration and desalting effect on crude oil than the crude oil desalter in Comparative Examples 1-2.

[0076] The preferred embodiments of the present invention disclosed above are only used to help illustrate the present invention. The preferred embodiments do not describe all the details in detail, nor do they limit the invention to the specific implementation methods described. Obviously, many modifications and changes can be made according to the content of this specification. This specification selects and specifically describes these embodiments in order to better explain the principles and practical applications of the present invention, so that those skilled in the art can understand and use the present invention well. The present invention is limited only by the claims and their full scope and equivalents.

Claims

1. A crude oil desalter, characterized in that: The invention comprises the following components by weight: 16-20 parts by weight of melamine-modified multi-branched polyether, 24-28 parts by weight of quaternized carboxyl chitosan-modified polyacrylate emulsion, and 5-9 parts by weight of graphene oxide; The preparation method of the melamine-modified multi-branched polyether comprises the following steps: (1) Add dibutylcarbamoyl chloride to anhydrous ethanol solvent, stir to dissolve, introduce nitrogen protection, heat to 80-85° C., add 1,3-dichlorotetraphenyldisiloxane, reflux for 4-8 hours, cool after the reaction, wash and dry to obtain acyl chloride silane gemini quaternary ammonium salt; (2) Add 25-30 g of melamine to the n-hexane solution, stir to dissolve, add 6-9 g of acyl chloride silane gemini quaternary ammonium salt dropwise thereto, react at 20-25° C. for 1-3 h, and after the reaction is completed, stand to separate the precipitates, wash with deionized water, filter and dry to obtain a quaternary ammonium salt modified melamine initiator; (3) Add 8-12 g of quaternary ammonium salt modified melamine initiator, 16-24 g of propylene oxide, and 0.06-0.09 g of potassium hydroxide catalyst to a high-pressure reactor, seal the reactor, purge with nitrogen for 3-5 minutes, heat to 140-150° C., react for 1-1.5 hours, cool to room temperature, add 12-15 g of ethylene oxide, heat to 120-135° C., continue to react for 2-3 hours, and after the reaction is completed, add 0.05-0.08 g of glacial acetic acid to neutralize the potassium hydroxide catalyst to obtain a melamine-modified multi-branched polyether; The preparation method of the quaternized carboxyl chitosan modified polyacrylate emulsion comprises the following steps: S1. Add 4-8 g of N-(1-naphthyl)-N-phenylmethyl acrylamide and 15-22 g of epichlorohydrin to the reactor, stir and mix, react at 24-30 ° C for 12-15 h, and after the reaction, extract and freeze-dry to obtain a naphthyl quaternary ammonium salt; S2. 6-9 g of carboxyl chitosan was added to deionized water, stirred to dissolve, 18-26 g of naphthyl quaternary ammonium salt was dissolved in deionized water, and then added dropwise to the carboxyl chitosan solution for 30-45 min, 0.02-0.05 g of potassium hydroxide was added to adjust the pH so that the pH value was maintained at 8-9 during the reaction, the temperature was raised to 75-85 ° C, the reaction was continued for 7-10 h, and after the reaction was completed, the mixture was cooled, dialyzed, and freeze-dried to obtain quaternized carboxyl chitosan; S3. 0.05-0.08 g of sodium dodecyl sulfate emulsifier was added to deionized water, stirred and heated to the reaction temperature, nitrogen was introduced for 30-40 min to remove oxygen, 0.06-0.09 g of ammonium persulfate initiator was added, stirred for 10-15 min, 7-10 g of ethyl methacrylate, 1-4 g of methacrylic acid, 4-6 g of quaternized carboxyl chitosan were added thereto, and the reaction was kept warm for 30-50 min, and then 0.03-0.05 g of ammonium persulfate initiator was added, and the reaction was kept warm for 20-40 min. After the reaction was completed, a quaternized carboxyl chitosan modified polyacrylate emulsion was obtained.

2. The crude oil desalting agent according to claim 1, characterized in that: In the step (1), the mass ratio of dibutylcarbamoyl chloride to 1,3-dichlorotetraphenyldisiloxane is 1:1.1-1.

15.

3. The crude oil desalting agent according to claim 1, characterized in that: In the step (2), the dripping time of the acyl chloride silane gemini quaternary ammonium salt is controlled within 50-80 minutes.

4. The crude oil desalting agent according to claim 1, characterized in that: The preparation method of the carboxyl chitosan in S2 is as follows: add 10-12g of chitosan to an acetic acid solution with a mass fraction of 1%-1.4%, stir to dissolve, add 12-15g of hydrated glyoxylic acid, react at 28-32°C for 3-6h, add 0.03-0.07g of sodium hydroxide to adjust the pH value to 4-5, add 3-6g of sodium borohydride solution with a mass fraction of 4.2%-4.8% dropwise for reduction for 10-15min, add anhydrous ethanol to precipitate, filter, and freeze-dry to obtain carboxyl chitosan.

5. The crude oil desalting agent according to claim 1, characterized in that: The reaction temperature in S3 is 72-80°C.

6. A method for preparing a crude oil desalter according to any one of claims 1 to 5, characterized in that: The preparation method of the crude oil desalter is as follows: adding melamine-modified multi-branched polyether, quaternized carboxyl chitosan-modified polyacrylate emulsion and graphene oxide into a reactor, stirring at 800-1400 rpm for 12-20 minutes, and obtaining the crude oil desalter.