Cationic polyether demulsifier and preparation method thereof

Abstract

The present invention belongs to the technical field of sewage treatment, and specifically relates to a cationic polyether demulsifier and a preparation method thereof. The preparation method is as follows: piperazine, 3-chloro-2-phenylpropanesulfonic acid sodium, and ethanol are added to a four-necked flask equipped with a condenser tube, heated and stirred, and the reaction is kept warm. Chloroacetic acid is added, and the reaction is refluxed to obtain a reaction solution; the above-mentioned reaction solution is decompressed and distilled to dryness to obtain a viscous solid, and recrystallized to obtain a light yellow solid; the above-mentioned light yellow solid and benzene are added to the autoclave, the pH value is adjusted, vacuumed, ethylene oxide is passed, heated, and the reaction is kept warm. The pressure of the reactor drops to 0, the reaction is stopped, and the temperature is lowered to below 40°C to obtain a mixed solution; the above-mentioned mixed solution is decompressed and distilled to obtain a viscous liquid, and ethanol is added to obtain a product demulsifier. The demulsifier of the present invention has the characteristics of simple synthesis process and high demulsification rate. When the concentration is 30mg / L, the oil removal rate reaches more than 98.5%.

Description

Technical Field

[0001] The invention belongs to the technical field of sewage treatment, and specifically relates to a cationic polyether demulsifier and a preparation method thereof. Background Art

[0002] Most of my country's oil fields have entered the middle and late stages of development. In order to stabilize and increase production, major oil fields have adopted various measures to increase produced fluids, resulting in a sharp increase in the water content of produced fluids. The water content has exceeded 90%, and the amount of wastewater treatment has increased significantly. There are generally two final destinations for wastewater treatment: (1) after treatment reaches the discharge standard, it is discharged; (2) after treatment reaches a certain standard, it is used as reinjection water for water injection mining or injected into waste formations. As environmental pressure increases, the state has increasingly restricted the discharge of oilfield wastewater that meets the standards. Shengli Oilfield has implemented zero discharge of produced water, that is, all the water in the produced fluid needs to be injected back into the formation.

[0003] The oil content of oilfield reinjection water is strictly required, and the wastewater needs to be treated for oil removal. The factors that affect the treatment effect of crude oil wastewater are mainly: various additives added during the oil production process make the wastewater have a high oil content, serious emulsification, complex composition, and large fluctuations in water quality; crude oil is a natural high-viscosity, high-molecular complex chemical substance, and is shallowly buried and mostly contained in gravel. During mining, a large amount of mineral components will inevitably be carried out from the strata. The water quality is high in hardness and has a large impurity content, which further increases the difficulty of treating crude oil wastewater; demulsifiers are added to the produced fluid during the dehydration and sedimentation process, and a large amount of chemical agents form a relatively stable emulsion. This kind of wastewater not only has a high oil content, but also has extremely strong emulsion stability.

[0004] There are several methods for demulsifying and dehydrating crude oil, such as electrical dehydration, wetting coalescence dehydration and chemical demulsification. Chemical demulsification is a commonly used method for dehydrating crude oil. It is to add demulsifiers to the crude oil emulsion to destroy its emulsified state and separate the oil and water into two layers. The main component of demulsifiers is surfactants.

[0005] CN104176788B discloses an oil remover for wastewater produced by binary composite flooding of oil fields and a preparation method thereof. The oil remover comprises acryloyloxyethyl dimethylamine, chloroalkane, acrylamide, N,N'-methylenebisacrylamide, ammonium persulfate and sodium sulfite. The preparation method of the oil remover is as follows: acryloyloxyethyl dimethylamine is reacted with chloroalkane (CnH2n+1Cln=1-12) to generate a cationic monomer; acrylamide and N,N'-methylenebisacrylamide are mixed, and added into deionized water three times, stirring while adding, and after complete dissolution, the prepared cationic monomer is added, and then ammonium persulfate and sodium sulfite solutions are added respectively, and the oil remover is obtained after stirring at a constant temperature of 45°C for 3-5 hours. The invention has the advantages of simple preparation, convenient use, small amount of reagent, low cost, high oil removal rate of more than 90%, and the recovered oil generated by separation does not affect the subsequent crude oil dehydration. Therefore, the invention can be widely used in the oil removal process of wastewater produced by binary composite flooding of oil fields. The on-site test concentration of the invention was 60 mg / L, and the oil content after treatment was still 68.2 mg / L. The demulsification and oil removal efficiency needs to be improved.

[0006] CN106565007 discloses a deoiling agent for produced water of ternary composite flooding. The deoiling agent is prepared by reacting 2,5-pyridinediamine with formaldehyde and formic acid to generate an intermediate, which is then reacted with sodium chlorododecanoate to generate a zwitterionic deoiling agent. The molar ratio of 2,5-pyridinediamine, formaldehyde, formic acid and sodium chlorododecanoate is 1:2.5-6:2.5-5.5:0.8-2.5, preferably 1:3:3:1.5. The deoiling agent of the invention has the characteristics of simple preparation, strong adaptability, low cost, strong salt resistance and good oil removal effect, and the salt resistance reaches 2.3×10 4 mg / L, the oil removal rate of ASP flooding produced water is over 97%. And the recovered oil produced by separation does not affect the subsequent crude oil dehydration. Therefore, the invention can be widely used in the oil removal process of ASP flooding produced water. However, pyridine is used in the synthesis of the product of the invention, which is highly toxic and easily causes environmental pollution. Summary of the invention

[0007] The present invention aims at the deficiencies of the current prior art and provides a cationic polyether demulsifier and a preparation method thereof. The demulsifier of the present invention has the characteristics of simple synthesis process and high demulsification rate. When the use concentration is 30 mg / L, the oil removal rate reaches more than 98.5%.

[0008] One of the purposes of the present invention is to provide a method for preparing a cationic polyether demulsifier, and the specific steps of the preparation method are as follows:

[0009] (1) adding piperazine, sodium 3-chloro-2-phenylpropanesulfonate and ethanol to a four-necked flask equipped with a condenser, heating and stirring, and reacting at 50-60° C., maintaining the pH of the mixed solution at 7-8 with a sodium hydroxide solution during the reaction, adding chloroacetic acid, and reflux reaction, maintaining the pH of the mixed solution at 7-8 with a sodium hydroxide solution during the reflux reaction, to obtain a reaction solution;

[0010] (2) distilling the reaction solution under reduced pressure to dryness to obtain a viscous solid, which was recrystallized from ethyl acetate to obtain a light yellow solid;

[0011] (3) Add the above-mentioned light yellow solid and benzene into a high-pressure reactor, adjust the pH to 3-4 with hydrochloric acid, purge the reactor with nitrogen, evacuate, introduce ethylene oxide, heat, and keep the reaction warm. When the pressure in the reactor drops to 0, stop the reaction, and cool to below 40° C. to obtain a mixed solution;

[0012] (4) The mixed solution is subjected to reduced pressure distillation, and the fraction below 80° C. is discarded to obtain a viscous liquid, and 50% of the weight of ethanol of the viscous liquid is added to obtain a demulsifier product.

[0013] In the present invention, preferably, the molar ratio of the sodium 3-chloro-2-phenylpropanesulfonate, chloroacetic acid, ethylene oxide and piperazine is 1.8-2.2:1.8-2.2:4-100:1; more preferably, the molar ratio of the sodium 3-chloro-2-phenylpropanesulfonate, chloroacetic acid, ethylene oxide and piperazine is 1.9-2.1:1.9-2.1:20-100:1.

[0014] In the present invention, preferably, the mass ratio of ethanol to piperazine in step (1) is 12-15:1.

[0015] Preferably, the insulation reaction time in step (1) is 1-2 h, and the reflux reaction time is 12-48 h.

[0016] More preferably, the insulation reaction time in step (1) is 1-1.5 h, and the reflux reaction time is 18-32 h.

[0017] In the present invention, preferably, the mass ratio of benzene to piperazine in step (3) is 8-10:1.

[0018] Preferably, the heating temperature in step (3) is 120-170°C; more preferably, the heating temperature is 120-150°C.

[0019] The reaction equation of the cationic polyether demulsifier of the present invention is:

[0020]

[0021]

[0022] Another object of the present invention is to disclose a cationic polyether demulsifier, the demulsifier molecular formula is as follows:

[0023]

[0024] Where:

[0025] m is a positive integer from 2 to 50;

[0026] n is a positive integer from 2 to 50.

[0027] The cationic polyether demulsifier of the present invention is a mixed surfactant of disodium betaine and nonionic type, wherein the cation is piperazine quaternary ammonium salt, the anion is sulfonic acid group, the surfactant lipophilic group is a double benzene ring, the hydrophilic group piperazine quaternary ammonium sulfonic acid group and the dioxyethylene ether segment. The surface of the emulsified oil droplets carries a negative charge and is very stable. The cationic group can neutralize the negative charge of the emulsified oil droplet interface film, compress and destroy the double electric layer, weaken the strength of the interface film, and make the emulsified droplets collide and coalesce, so that the oil droplets lose the repulsive effect and gather together, so that the tiny oil droplets gather and release to form oil droplets with large particle size, thereby achieving the purpose of demulsification; the molecule of the present invention can enter the oil-water interface, replace the surfactant with strong emulsification, replace the surfactant molecules and other surface active substances, and form a mixed film with the film-forming substances in the emulsified oil with a lower interface film strength than the original one, resulting in the destruction of the interface film, making it easier for small oil droplets to approach and condense to form large oil droplets to achieve the purpose of demulsification; the polyether segment in the molecule of the present invention has high flexibility and is curled in water. The area of ​​the demulsifier monomolecule adsorbed on the interface increases, which affects the close arrangement of the demulsifier molecules on the interface, and the ability to reduce the viscosity and interface elasticity of the oil-water interface also increases, thereby reducing the strength of the oil-water interface film, resulting in a shortened oil film life, accelerated film thinning speed, and increased dehydration rate of the crude oil emulsion, thereby demulsification.

[0028] Compared with the prior art, the present invention has the following advantages and beneficial effects:

[0029] (1) The demulsifier synthesis raw materials of the present invention are cheap, widely available, simple in synthesis process, safe and environmentally friendly;

[0030] (2) The demulsifier of the present invention has a good demulsification effect. When the concentration is 30 mg / L, the oil removal rate reaches more than 98.5%. DETAILED DESCRIPTION

[0031] The present invention will be further described in detail below in conjunction with specific examples and with reference to data. It should be understood that these examples are only intended to illustrate the present invention and are not intended to limit the scope of the present invention in any way.

[0032] Example 1

[0033] (1) Add 1 mol of piperazine, 1.8 mol of sodium 3-chloro-2-phenylpropanesulfonate, and 1032 g of ethanol to a four-necked flask equipped with a condenser, heat and stir, and keep the mixture at 50° C. for 1 hour. During the reaction, a 2 mol / L sodium hydroxide solution is used to maintain the pH of the mixed solution at 7-8. Add 2.2 mol of chloroacetic acid, and reflux for 12 hours. During the reflux reaction, a 2 mol / L sodium hydroxide solution is used to maintain the pH of the mixed solution at 7-8 to obtain a reaction solution;

[0034] (2) distilling the reaction solution in (1) to dryness under reduced pressure to obtain a viscous solid, which was recrystallized from ethyl acetate to obtain a light yellow solid;

[0035] (3) Add the light yellow solid obtained in (2) and 860 g of benzene into a high-pressure reactor, adjust the pH to 3-4 with 2 mol / L hydrochloric acid, purge the reactor with nitrogen, and evacuate. Pass 4 mol of ethylene oxide, heat to 120°C, and keep the temperature for reaction. When the pressure in the reactor drops to 0, stop the reaction, cool to below 40°C, and obtain a mixed solution;

[0036] (4) The mixed solution of (3) was subjected to reduced pressure distillation, and the fraction below 80° C. was discarded to obtain a viscous liquid, and 50% of the weight of ethanol of the viscous liquid was added to obtain the product demulsifier S1.

[0037] Example 2

[0038] (1) Add 1 mol of piperazine, 1.85 mol of sodium 3-chloro-2-phenylpropanesulfonate, and 1124 g of ethanol to a four-necked flask equipped with a condenser, heat and stir, and react at 60° C. for 1.7 hours. During the reaction, a 2 mol / L sodium hydroxide solution is used to maintain the pH of the mixed solution at 7-8. Add 1.8 mol of chloroacetic acid, and reflux for 16 hours. During the reflux reaction, a 2 mol / L sodium hydroxide solution is used to maintain the pH of the mixed solution at 7-8 to obtain a reaction solution;

[0039] (2) distilling the reaction solution in (1) to dryness under reduced pressure to obtain a viscous solid, which was recrystallized from ethyl acetate to obtain a light yellow solid;

[0040] (3) Add the light yellow solid obtained in (2) and 840 g of benzene into a high-pressure reactor, adjust the pH to 3-4 with 2 mol / L hydrochloric acid, purge the reactor with nitrogen, and evacuate. Pass 10 mol of ethylene oxide, heat to 130°C, and keep the temperature for reaction. When the pressure in the reactor drops to 0, stop the reaction, cool to below 40°C, and obtain a mixed solution;

[0041] (4) The mixed solution of (3) is subjected to reduced pressure distillation, and the fraction below 80° C. is discarded to obtain a viscous liquid, and 50% of the weight of ethanol of the viscous liquid is added to obtain the product demulsifier S2.

[0042] Example 3

[0043] (1) Add 1 mol of piperazine, 2.2 mol of sodium 3-chloro-2-phenylpropanesulfonate, and 1240 g of ethanol to a four-necked flask equipped with a condenser, heat and stir, and keep the mixture at 52° C. for 1 hour. During the reaction, a 2 mol / L sodium hydroxide solution is used to maintain the pH of the mixed solution at 7-8. Add 1.85 mol of chloroacetic acid, and reflux for 24 hours. During the reflux reaction, a 2 mol / L sodium hydroxide solution is used to maintain the pH of the mixed solution at 7-8 to obtain a reaction solution;

[0044] (2) distilling the reaction solution in (1) to dryness under reduced pressure to obtain a viscous solid, which was recrystallized from ethyl acetate to obtain a light yellow solid;

[0045] (3) Add the light yellow solid obtained in (2) and 820 g of benzene into a high-pressure reactor, adjust the pH to 3-4 with 2 mol / L hydrochloric acid, purge the reactor with nitrogen, and evacuate. Pass 15 mol of ethylene oxide, heat to 135°C, and keep the temperature for reaction. When the pressure in the reactor drops to 0, stop the reaction, cool to below 40°C, and obtain a mixed solution;

[0046] (4) The mixed solution of (3) was subjected to reduced pressure distillation, and the fraction below 80° C. was discarded to obtain a viscous liquid, and 50% of the weight of ethanol of the viscous liquid was added to obtain the product demulsifier S3.

[0047] Example 4

[0048] (1) Add 1 mol of piperazine, 2.15 mol of sodium 3-chloro-2-phenylpropanesulfonate, and 1180 g of ethanol to a four-necked flask equipped with a condenser, heat and stir, and keep the mixture at 55° C. for 1.3 h. During the reaction, a 2 mol / L sodium hydroxide solution was used to maintain the pH of the mixed solution at 7-8. 1.9 mol of chloroacetic acid was added, and the mixture was refluxed for 30 h. During the reflux reaction, a 2 mol / L sodium hydroxide solution was used to maintain the pH of the mixed solution at 7-8 to obtain a reaction solution.

[0049] (2) distilling the reaction solution in (1) to dryness under reduced pressure to obtain a viscous solid, which was recrystallized from ethyl acetate to obtain a light yellow solid;

[0050] (3) Add the light yellow solid obtained in (2) and 801 g of benzene into a high-pressure reactor, adjust the pH to 3-4 with 2 mol / L hydrochloric acid, purge the reactor with nitrogen, and evacuate. Pass 20 mol of ethylene oxide, heat to 140°C, and keep the temperature for reaction. When the pressure in the reactor drops to 0, stop the reaction, cool to below 40°C, and obtain a mixed solution;

[0051] (4) The mixed solution of (3) was subjected to reduced pressure distillation, and the fraction below 80° C. was discarded to obtain a viscous liquid, and 50% of the weight of ethanol of the viscous liquid was added to obtain the product demulsifier S4.

[0052] Example 5

[0053] (1) Add 1 mol of piperazine, 1.9 mol of sodium 3-chloro-2-phenylpropanesulfonate, and 1250 g of ethanol to a four-necked flask equipped with a condenser, heat and stir, and keep the mixture at 55° C. for 1.8 hours. During the reaction, a 2 mol / L sodium hydroxide solution is used to maintain the pH of the mixed solution at 7-8. Add 2.15 mol of chloroacetic acid, and reflux for 36 hours. During the reflux reaction, a 2 mol / L sodium hydroxide solution is used to maintain the pH of the mixed solution at 7-8 to obtain a reaction solution;

[0054] (2) distilling the reaction solution in (1) to dryness under reduced pressure to obtain a viscous solid, which was recrystallized from ethyl acetate to obtain a light yellow solid;

[0055] (3) Add the light yellow solid obtained in (2) and 700 g of benzene into a high-pressure reactor, adjust the pH to 3-4 with 2 mol / L hydrochloric acid, purge the reactor with nitrogen, and evacuate. Pass 30 mol of ethylene oxide, heat to 140°C, and keep the temperature for reaction. When the pressure in the reactor drops to 0, stop the reaction, cool to below 40°C, and obtain a mixed solution;

[0056] (4) The mixed solution of (3) was subjected to reduced pressure distillation, and the fraction below 80° C. was discarded to obtain a viscous liquid, and 50% of the weight of ethanol of the viscous liquid was added to obtain the product demulsifier S5.

[0057] Example 6

[0058] (1) Add 1 mol of piperazine, 2.1 mol of sodium 3-chloro-2-phenylpropanesulfonate, and 1190 g of ethanol to a four-necked flask equipped with a condenser, heat and stir, and keep the mixture at 53° C. for 1.2 h. During the reaction, a 2 mol / L sodium hydroxide solution was used to maintain the pH of the mixed solution at 7-8. Add 2 mol of chloroacetic acid, and reflux for 40 h. During the reflux reaction, a 2 mol / L sodium hydroxide solution was used to maintain the pH of the mixed solution at 7-8 to obtain a reaction solution.

[0059] (2) distilling the reaction solution in (1) to dryness under reduced pressure to obtain a viscous solid, which was recrystallized from ethyl acetate to obtain a light yellow solid;

[0060] (3) Add the light yellow solid obtained in (2) and 702 g of benzene into a high-pressure reactor, adjust the pH to 3-4 with 2 mol / L hydrochloric acid, purge the reactor with nitrogen, and evacuate. Pass 50 mol of ethylene oxide, heat to 150°C, and keep the temperature to react. When the pressure in the reactor drops to 0, stop the reaction, cool to below 40°C, and obtain a mixed solution;

[0061] (4) The mixed solution of (3) was subjected to reduced pressure distillation, and the fraction below 80° C. was discarded to obtain a viscous liquid, and 50% of the weight of ethanol of the viscous liquid was added to obtain the product demulsifier S6.

[0062] Example 7

[0063] (1) Add 1 mol of piperazine, 1.95 mol of sodium 3-chloro-2-phenylpropanesulfonate, and 1200 g of ethanol to a four-necked flask equipped with a condenser, heat and stir, and react at 57° C. for 1.8 hours. During the reaction, a 2 mol / L sodium hydroxide solution is used to maintain the pH of the mixed solution at 7-8. Add 2.05 mol of chloroacetic acid, and reflux for 42 hours. During the reflux reaction, a 2 mol / L sodium hydroxide solution is used to maintain the pH of the mixed solution at 7-8 to obtain a reaction solution;

[0064] (2) distilling the reaction solution in (1) to dryness under reduced pressure to obtain a viscous solid, which was recrystallized from ethyl acetate to obtain a light yellow solid;

[0065] (3) Add the light yellow solid obtained in (2) and 745 g of benzene into a high-pressure reactor, adjust the pH to 3-4 with 2 mol / L hydrochloric acid, purge the reactor with nitrogen, and evacuate. Pass 70 mol of ethylene oxide, heat to 160°C, and keep the temperature for reaction. When the pressure in the reactor drops to 0, stop the reaction, cool to below 40°C, and obtain a mixed solution;

[0066] (4) The mixed solution of (3) was subjected to reduced pressure distillation, and the fraction below 80° C. was discarded to obtain a viscous liquid, and 50% of the weight of ethanol of the viscous liquid was added to obtain the product demulsifier S7.

[0067] Example 8

[0068] (1) Add 1 mol of piperazine, 2.05 mol of sodium 3-chloro-2-phenylpropanesulfonate, and 1290 g of ethanol to a four-necked flask equipped with a condenser, heat and stir, and keep the mixture at 58° C. for 2 h. During the reaction, a 2 mol / L sodium hydroxide solution was used to maintain the pH of the mixed solution at 7-8. Add 2.05 mol of chloroacetic acid, and reflux for 48 h. During the reflux reaction, a 2 mol / L sodium hydroxide solution was used to maintain the pH of the mixed solution at 7-8 to obtain a reaction solution.

[0069] (2) distilling the reaction solution in (1) to dryness under reduced pressure to obtain a viscous solid, which was recrystallized from ethyl acetate to obtain a light yellow solid;

[0070] (3) Add the light yellow solid obtained in (2) and 725 g of benzene into a high-pressure reactor, adjust the pH to 3-4 with 2 mol / L hydrochloric acid, purge the reactor with nitrogen, and evacuate. Pass 90 mol of ethylene oxide, heat to 170°C, and keep the temperature for reaction. When the pressure in the reactor drops to 0, stop the reaction, cool to below 40°C, and obtain a mixed solution;

[0071] (4) The mixed solution of (3) was subjected to reduced pressure distillation, and the fraction below 80° C. was discarded to obtain a viscous liquid, and 50% of the weight of ethanol of the viscous liquid was added to obtain the product demulsifier S8.

[0072] Example 9

[0073] (1) Add 1 mol of piperazine, 2 mol of sodium 3-chloro-2-phenylpropanesulfonate, and 1280 g of ethanol to a four-necked flask equipped with a condenser, heat and stir, and keep the mixture at 56° C. for 1.5 h. During the reaction, a 2 mol / L sodium hydroxide solution was used to maintain the pH of the mixed solution at 7-8. 1.95 mol of chloroacetic acid was added, and the mixture was refluxed for 42 h. During the reflux reaction, a 2 mol / L sodium hydroxide solution was used to maintain the pH of the mixed solution at 7-8 to obtain a reaction solution.

[0074] (2) distilling the reaction solution in (1) to dryness under reduced pressure to obtain a viscous solid, which was recrystallized from ethyl acetate to obtain a light yellow solid;

[0075] (3) Add the light yellow solid obtained in (2) and 770 g of benzene into a high-pressure reactor, adjust the pH to 3-4 with 2 mol / L hydrochloric acid, purge the reactor with nitrogen, and evacuate. Pass 100 mol of ethylene oxide, heat to 170°C, and keep the temperature for reaction. When the pressure in the reactor drops to 0, stop the reaction, cool to below 40°C, and obtain a mixed solution;

[0076] (4) The mixed solution of (3) was subjected to reduced pressure distillation, and the fraction below 80° C. was discarded to obtain a viscous liquid, and 50% of the weight of ethanol of the viscous liquid was added to obtain the product demulsifier S9.

[0077] Test Example 1 Evaluation of Demulsifier Indoor Effect

[0078] Demulsification experiments were carried out on produced water from ASP flooding of a certain oil field using the present invention at different concentrations, and the experimental method was based on SY / T5797-1993 "Method for evaluating the performance of demulsifiers for oil-in-water emulsions".

[0079] Produced water properties: oil content, 1580mg / L, temperature 75℃, mineralization, 35600mg / L

[0080] Demulsifier concentration: 10, 20, 30 mg / L

[0081] Comparison demulsifier: SPX-8603

[0082] The experimental results are shown in Table 1.

[0083] Table 1 Demulsifier demulsification test results (oil removal rate, %)

[0084] Demulsifier 10mg / L,% 20mg / L,% 30mg / L,% <![CDATA[S1]]> 87.2 94.8 99.0 <![CDATA[S2]]> 88.9 95.7 98.9 <![CDATA[S3]]> 91.3 96.4 98.6 <![CDATA[S4]]> 94.9 97.5 99.1 <![CDATA[S5]]> 94.3 97.3 99.2 <![CDATA[S6]]> 95.5 97.8 99.0 <![CDATA[S7]]> 95.6 98.3 99.2 <![CDATA[S8]]> 96 98.5 99.5 <![CDATA[S9]]> 95.8 98.3 99.4 SPX-8603 72.3 85.3 90.3

[0085] From Table 1 we can see that:

[0086] (1) The demulsifiers S1-S9 of the present invention have an oil removal rate of 87% or more when used at a concentration of 10 mg / L, with the highest reaching 95.8%; while the oil removal rate of SPX-8603 is 72.3% when used at a concentration of 10 mg / L;

[0087] (2) The demulsifiers S1-S9 of the present invention have an oil removal rate of 94% or more when used at a concentration of 20 mg / L, with the highest reaching 98.5%; while the oil removal rate of SPX-8603 is 85.3% when used at a concentration of 20 mg / L;

[0088] (3) The oil removal rate of the polyether demulsifiers S1-S9 of the present invention reaches 98.5% or more when the concentration is 30 mg / L, and the highest reaches 99.5%; while the oil removal rate of SPX-8603 is 90.3% when the concentration is 30 mg / L. Compared with the prior art products, the demulsifier of the present invention has a good oil removal effect.

[0089] Application Example 1: On-site application of demulsifier

[0090] A field test was conducted at a water injection station. The treatment object was ASP flooding produced water, which had an oil content of 1250 mg / L, a mineralization of 24500 mg / L, and a temperature of 70°C. The test treatment scale was 120m 3 The demulsifier S8 of the present invention was used to demulsify the produced water. The dosage of the demulsifier S8 was 3.6 kg / d and the concentration was 30 mg / L. After the treatment, the oil content of the produced water was reduced to 5 mg / L, and the oil removal rate reached 99.6%, meeting the oil content requirement of Class I reinjection water.

Claims

1. A method for preparing a cationic polyether demulsifier, characterized in that: The specific steps of the preparation method are as follows: (1) adding piperazine, sodium 3-chloro-2-phenylpropanesulfonate and ethanol to a four-necked flask equipped with a condenser, heating and stirring, and reacting at 50-60° C., maintaining the pH of the mixed solution at 7-8 with a sodium hydroxide solution during the reaction, adding chloroacetic acid, and reflux reaction, maintaining the pH of the mixed solution at 7-8 with a sodium hydroxide solution during the reflux reaction, to obtain a reaction solution; (2) distilling the reaction solution under reduced pressure to dryness to obtain a viscous solid, which was recrystallized from ethyl acetate to obtain a light yellow solid; (3) Add the above-mentioned light yellow solid and benzene into a high-pressure reactor, adjust the pH to 3-4 with hydrochloric acid, purge the reactor with nitrogen, evacuate, introduce ethylene oxide, heat, and keep the reaction warm. When the pressure in the reactor drops to 0, stop the reaction, and cool to below 40° C. to obtain a mixed solution; (4) The mixed solution is subjected to reduced pressure distillation, and the fraction below 80° C. is discarded to obtain a viscous liquid, and 50% of the weight of ethanol of the viscous liquid is added to obtain a demulsifier product.

2. The method for preparing a cationic polyether demulsifier according to claim 1, characterized in that: The molar ratio of the sodium 3-chloro-2-phenylpropanesulfonate, chloroacetic acid, ethylene oxide and piperazine is 1.8-2.2:1.8-2.2:4-100:

1.

3. The method for preparing a cationic polyether demulsifier according to claim 2, characterized in that: The molar ratio of the sodium 3-chloro-2-phenylpropanesulfonate, chloroacetic acid, ethylene oxide and piperazine is 1.9-2.1:1.9-2.1:20-100:

1.

4. The method for preparing a cationic polyether demulsifier according to claim 1, characterized in that: The mass ratio of ethanol to piperazine in step (1) is 12-15:

1.

5. The method for preparing a cationic polyether demulsifier according to claim 1, characterized in that: The insulation reaction time in step (1) is 1-2 hours, and the reflux reaction time is 12-48 hours.

6. The method for preparing a cationic polyether demulsifier according to claim 5, characterized in that: The insulation reaction time is 1-1.5h, and the reflux reaction time is 18-32h.

7. The method for preparing a cationic polyether demulsifier according to claim 1, characterized in that: The mass ratio of benzene to piperazine in step (3) is 8-10:

1.

8. The method for preparing a cationic polyether demulsifier according to claim 1, characterized in that: The heating temperature in step (3) is 120-170°C.

9. The method for preparing a cationic polyether demulsifier according to claim 8, characterized in that: The heating temperature is 120-150°C.

10. A cationic polyether demulsifier, characterized in that: The demulsifier molecular formula is as follows: Where: m is a positive integer from 2 to 50; n is a positive integer from 2 to 50.

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