A multifunctional polymer demulsifier and preparation method thereof

Abstract

The present invention belongs to the technical field of sewage treatment, and in particular to a kind of multifunctional polymer demulsifier and preparation method thereof. The preparation method specifically comprises the following steps: purging the reactor and pipeline with nitrogen, sequentially adding N (4 vinylbenzyl) N, N dimethylamine, 2 methacryloyloxyethyl phosphorylcholine, 1 vinyl 3 ethyl imidazole bromide, buffer salt, deionized water, stirring evenly, adjusting pH7 8 with ammonia;High-position dripping tank adds initiator solution, slowly drips in reactor, continues to heat to 50 60 DEG C, insulation reaction 1 2h, cools to less than 40 DEG C, adjusts pH7 8 with ammonia, obtains viscous liquid;With granulator, above-mentioned viscous liquid is dried and granulated to obtain product demulsifier. The demulsifier of the present invention has the characteristics that raw material sources are wide, synthesis process is simple, degreasing, flocculation, sterilization three functions are in one.

Description

Technical Field

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

[0002] Currently, major oil fields have entered the secondary and tertiary recovery stages. To maximize the recovery of stratum crude oil, a large number of surfactants and polymers are used during the construction process. While this has improved the recovery rate, it has also brought about problems in produced water treatment. This results in a large amount of suspended oil and emulsified oil in the produced water. The oil droplets in these wastewaters are small and stably present in the water, making oil-water separation difficult. Treated wastewater cannot meet the needs of oil well reinjection. Directly reinjecting untreated wastewater into the bottom layer can cause blockage of the injection well, reduce the pore permeability of the oil layer, hinder water injection oil recovery, and increase the injection pressure, which directly affects crude oil production.

[0003] SYT 5329-2012 "Water Quality Indicators and Analysis Methods for Injection Water in Clastic Rock Reservoirs" has strict regulations on injection water quality, especially for oil content, suspended matter, and bacterial content, with clear reinjection indicators. Failure to meet the requirements will affect the reinjection effect, leading to increased injection pressure and energy consumption, and will damage the formation, seriously affecting the recovery rate.

[0004] Currently, the primary wastewater treatment process at oilfield joint stations is sedimentation-coagulation-filtration, which is difficult to achieve satisfactory treatment results. Furthermore, coagulation and sedimentation also produce a large amount of sludge. Flotation involves introducing air into the wastewater, creating tiny bubbles that act as carriers. These bubbles cause pollutants such as emulsified oil and suspended solids in the wastewater to adhere to the bubbles and rise to the surface. The bubbles are then collected to separate impurities and purify the wastewater. Flotation is a relatively low-cost method for oil removal, but it presents two challenges: first, the introduction of oxygen during the flotation process can corrode oil well equipment; second, pure flotation treatment is ineffective, often requiring chemical agents for optimal oil removal.

[0005] Currently, the most common flocculants used for oilfield wastewater are PAC and PAM compounds. These need to be added in two stages, which is complex to operate. Furthermore, different water types require different compound concentrations, making on-site operations more difficult.

[0006] CN104291412A discloses a method for preparing a reverse demulsifier for treating polymer-containing oil production wastewater. The method first uses epichlorohydrin as a raw material to synthesize polyepichlorohydrin (PECH) through a self-polymerization reaction, and then reacts with an organic amine and carbon disulfide to obtain a brown-red viscous liquid. The present invention also provides a reverse demulsifier prepared by this method. The reverse demulsifier is an anionic polymer with a network structure, which is a brown-red viscous liquid. The rotational viscosity tested at 30°C and a rotation speed of 100r / min is 120-140cp. Evaluation tests show that the network anionic reverse demulsifier product prepared by this method has a good water purification effect, dense flocs, and clear water quality, and is particularly suitable for treating polymer-containing oil production wastewater. The reverse demulsifier of the invention has a single composition and a simple reverse demulsification principle. It is limited in treating complex oilfield oily wastewater and cannot meet the needs of oilfield production.

[0007] CN107879447A discloses a method for preparing a flocculant for treating oily wastewater. The method mainly uses chitosan as the main raw material, and adds polyferric sulfate, polyaluminum sulfate, polydimethyldiallylammonium chloride and diphenylthiourea copper complex for modification during the preparation process. The amino and carboxyl groups in the chitosan molecules form stable chelates with heavy metal ions such as mercury, lithium, copper, lead, and silver in the wastewater, thereby removing and recovering the metal ions in the wastewater. The flocculant prepared by the present invention has good adsorption effect. The better the biocompatibility, the stronger its adsorption effect on oil pollution. In sewage treatment, it can also be used for decolorization of wastewater, adsorption and flocculation reaction of wastewater in industrial production, etc., and has great promotion and application value. The flocculant contains an inorganic flocculant, which has the disadvantages of large usage, large sludge production, easy corrosion of equipment, and secondary pollution. In addition, the use process is relatively cumbersome and difficult to promote. Summary of the Invention

[0008] In response to the deficiencies of the above-mentioned prior art, the present invention provides a multifunctional polymer demulsifier and a preparation method thereof. The demulsifier of the present invention has the characteristics of a wide source of raw materials, a simple synthesis process, and the integration of oil removal, flocculation, and sterilization. When the concentration is 8 mg / L, the oil removal rate and flocculation rate reach above 98% and above 95%, respectively. When the concentration is 30 mg / L, the sterilization rate reaches 100%.

[0009] In order to achieve the above objectives, the first aspect of the present invention discloses a multifunctional polymer demulsifier, the molecular structure of which is as follows:

[0010]

[0011] wherein x=10,000-100,000, more preferably x=20,000-50,000;

[0012] y=1000-10000, more preferably x=3000-5000;

[0013] z=5000-50000, more preferably x=10000-20000.

[0014] The viscosity average molecular weight of the demulsifier is 5,000,000-20,000,000.

[0015] According to a second aspect of the present invention, the present invention discloses a method for preparing a multifunctional polymer demulsifier, wherein the specific steps of the preparation method are as follows:

[0016] (1) Purge the reactor and pipelines with nitrogen at a ventilation rate of 2000-2500 ml / L. After 5-10 minutes, adjust the ventilation rate to 100-200 ml / L. Maintain a nitrogen atmosphere throughout the later synthesis process. Add N-(4-vinylbenzyl)-N,N-dimethylamine, 2-methacryloyloxyethyl phosphorylcholine, 1-vinyl-3-ethylimidazolium bromide, buffer salt, and deionized water in sequence, stir evenly, and adjust the pH to 7-8 with 10-15 wt% ammonia water;

[0017] (2) Add the initiator solution to the high-position dropping tank and slowly add it dropwise into the reactor. The initiator addition time is controlled at 60-90 min. After the addition is completed, stir for 30-40 min, continue to heat to 50-60 ° C, keep the temperature for reaction for 1-2 h, cool to below 40 ° C, and adjust the pH to 7-8 with 10-15 wt% ammonia water to obtain a viscous liquid;

[0018] (3) The viscous liquid is dried and granulated into particles with a diameter of 0.4-1 mm using a granulator to obtain a demulsifier product.

[0019] In the present invention, preferably, based on 1 mole of N-(4-vinylbenzyl)-N,N-dimethylamine, the amounts of 2-methacryloyloxyethyl phosphorylcholine and 1-vinyl-3-ethylimidazolium bromide are 0.05-0.2 mole parts and 0.3-0.8 mole parts, respectively; more preferably, based on 1 mole of N-(4-vinylbenzyl)-N,N-dimethylamine, the amounts of 2-methacryloyloxyethyl phosphorylcholine and 1-vinyl-3-ethylimidazolium bromide are 0.1-0.15 mole parts and 0.3-0.5 mole parts, respectively.

[0020] Preferably, the buffer salt in step (1) is one of sodium dihydrogen phosphate, potassium dihydrogen phosphate, ammonium dihydrogen phosphate, disodium hydrogen phosphate, dipotassium hydrogen phosphate, and diammonium hydrogen phosphate; more preferably, it is one of sodium dihydrogen phosphate, potassium dihydrogen phosphate, and ammonium dihydrogen phosphate.

[0021] Preferably, the weight ratio of the buffer salt to N-(4-vinylbenzyl)-N,N-dimethylamine in step (1) is 0.05-0.1:1.

[0022] Preferably, the weight ratio of deionized water to N-(4-vinylbenzyl)-N,N-dimethylamine in step (1) is 6-10:1.

[0023] In the present invention, preferably, the initiator in step (2) is an azo compound system or a redox system, and the weight ratio of the initiator to N-(4-vinylbenzyl)-N,N-dimethylamine is 0.02-0.1:1.

[0024] More preferably, the azo compound system is azobisisobutyronitrile or azobisisoheptanenitrile.

[0025] More preferably, the redox system is a mixture of persulfate and sodium sulfite, and the mass ratio of persulfate to sodium sulfite is 2-3:1.

[0026] More preferably, the persulfate is one of sodium persulfate, ammonium persulfate and potassium persulfate.

[0027] The multifunctional polymer demulsifier synthesis reaction equation of the present invention is as follows:

[0028]

[0029] The demulsifier provided by the present invention is a high molecular surfactant, which is polymerized by three functional monomers and has the three-in-one functions of demulsification and oil removal, flocculation, and sterilization. It contains non-polar groups such as phenyl and high-polymer long-chain alkyl, and polar groups such as quaternary ammonium, tertiary amine, imidazole, and phosphate. The non-polar group is lipophilic and can adsorb with the oil in the sewage, so that one side of the molecule penetrates into the oil pollution, and the emulsified oil and dissolved oil in the sewage are extracted through penetration, emulsification, and stripping to form relatively stable flocs, which are dispersed and floated on the surface of the solution, thereby achieving demulsification and flocculation; the cationic group adsorbs negatively charged bacteria, and the hydrophobic group inserts into the lipid layer, changes the permeability of the cell membrane, destroys the membrane structure, denatures the protein, affects the cell metabolic process, and finally kills the bacteria, thereby achieving a sterilization effect; the cationic group can capture a large amount of negatively charged suspended solids, and the bridging effect connects these suspended solids, so that flocculation is easy to occur, thereby enhancing the demulsification and oil removal effect.

[0030] Compared with the prior art, the present invention has the following advantages and beneficial effects:

[0031] (1) The raw materials of the demulsifier of the present invention are widely available, the synthesis process is simple, it is a one-pot synthesis, and there are no by-products;

[0032] (2) The demulsifier of the present invention has a high oil removal rate and flocculation rate. When the concentration is 8 mg / L, the oil removal rate reaches more than 98% and the flocculation rate reaches more than 95%;

[0033] (3) The demulsifier of the present invention has a strong sterilization rate. When the concentration is 30 mg / L, the sterilization rate reaches 100%. DETAILED DESCRIPTION

[0034] The technical solution of the present invention is further described below with reference to the embodiments:

[0035] Example 1

[0036] (1) The reactor and pipelines were purged with nitrogen at a ventilation rate of 2000 ml / L. After 5 minutes, the ventilation rate was adjusted to 100 ml / L. A nitrogen atmosphere was maintained throughout the subsequent synthesis process. 1 mol N-(4-vinylbenzyl)-N,N-dimethylamine, 0.05 mol 2-methacryloyloxyethyl phosphorylcholine, 0.5 mol 1-vinyl-3-ethylimidazolium bromide, 8.05 g sodium dihydrogen phosphate, and 966 g deionized water were added in sequence, stirred evenly, and the pH was adjusted to 7-8 with 10 wt% ammonia water.

[0037] (2) Add an initiator solution to the high-position drop tank. The initiator solution is 3.22 g of azobisisobutyronitrile dissolved in 16.44 g of toluene. Slowly add the solution dropwise to the reactor. The initiator addition time is controlled within 60 min. After the addition is completed, stir for 30 min, continue to heat to 50 ° C, keep the temperature for reaction for 1 h, cool to below 40 ° C, and adjust the pH to 7-8 with 10 wt% ammonia water to obtain a viscous liquid.

[0038] (3) The viscous liquid is dried and granulated into particles with a diameter of 0.4-1 mm using a granulator to obtain the product demulsifier M1.

[0039] Example 2

[0040] (1) The reactor and pipelines were purged with nitrogen at a ventilation rate of 2500 ml / L. After 6 minutes, the ventilation rate was adjusted to 150 ml / L. The nitrogen atmosphere was maintained throughout the subsequent synthesis process. 1 mol N-(4-vinylbenzyl)-N,N-dimethylamine, 0.07 mol 2-methacryloyloxyethyl phosphorylcholine, 0.8 mol 1-vinyl-3-ethylimidazolium bromide, 9.17 g sodium dihydrogen phosphate, and 1044 g deionized water were added in sequence, stirred evenly, and the pH was adjusted to 7-8 with 12 wt% ammonia water.

[0041] (2) Add an initiator solution to the high-position drop tank. The initiator solution is 4.25 g of azobisisobutyronitrile dissolved in 21.33 g of toluene. Slowly add the initiator solution dropwise to the reactor. The initiator addition time is controlled within 90 min. After the addition is completed, stir for 40 min, continue to heat to 60 ° C, keep the temperature for reaction for 2 h, cool to below 40 ° C, and adjust the pH to 7-8 with 12 wt% ammonia water to obtain a viscous liquid.

[0042] (3) The viscous liquid is dried and granulated into particles with a diameter of 0.4-1 mm using a granulator to obtain the product demulsifier M2.

[0043] Example 3

[0044] (1) The reactor and pipelines were purged with nitrogen at a ventilation rate of 2100 ml / L. After 8 minutes, the ventilation rate was adjusted to 200 ml / L. The nitrogen atmosphere was maintained throughout the subsequent synthesis process. 1 mol N-(4-vinylbenzyl)-N,N-dimethylamine, 0.09 mol 2-methacryloyloxyethyl phosphorylcholine, 0.7 mol 1-vinyl-3-ethylimidazolium bromide, 10.32 g sodium dihydrogen phosphate, and 1235 g deionized water were added in sequence, stirred evenly, and the pH was adjusted to 7-8 with 13 wt% ammonia water;

[0045] (2) Add an initiator solution to the high-position dropping tank. The initiator solution is 5.78 g of azobisisoheptanonitrile dissolved in 32.44 g of toluene. Slowly add the solution dropwise to the reactor. The initiator addition time is controlled within 70 min. After the addition is complete, stir for 40 min, continue to heat to 58 ° C, keep the temperature for reaction for 1.5 h, cool to below 40 ° C, and adjust the pH to 7-8 with 13 wt% ammonia water to obtain a viscous liquid.

[0046] (3) The viscous liquid was dried and granulated into particles with a diameter of 0.4-1 mm using a granulator to obtain the product demulsifier M3.

[0047] Example 4

[0048] (1) The reactor and pipelines were purged with nitrogen at a ventilation rate of 2200 ml / L. After 6 minutes, the ventilation rate was adjusted to 120 ml / L. The nitrogen atmosphere was maintained throughout the subsequent synthesis process. 1 mol N-(4-vinylbenzyl)-N,N-dimethylamine, 0.11 mol 2-methacryloyloxyethyl phosphorylcholine, 0.6 mol 1-vinyl-3-ethylimidazolium bromide, 16.1 g potassium dihydrogen phosphate, and 1300 g deionized water were added in sequence, stirred evenly, and the pH was adjusted to 7-8 with 15 wt% ammonia water;

[0049] (2) Add an initiator solution to the high-position drop tank. The initiator solution is 7.77 g of azobisisoheptanonitrile dissolved in 35.66 g of toluene. Slowly add the solution dropwise to the reactor. The initiator addition time is controlled within 80 min. After the addition is complete, stir for 30 min, continue to heat to 57 ° C, keep the temperature for reaction for 1.2 h, cool to below 40 ° C, and adjust the pH to 7-8 with 15 wt% ammonia water to obtain a viscous liquid.

[0050] (3) The viscous liquid was dried and granulated into particles with a diameter of 0.4-1 mm using a granulator to obtain the product demulsifier M4.

[0051] Example 5

[0052] (1) The reactor and pipelines were purged with nitrogen at a ventilation rate of 2300 ml / L. After 10 min, the ventilation rate was adjusted to 150 ml / L. The nitrogen atmosphere was maintained throughout the subsequent synthesis process. 1 mol N-(4-vinylbenzyl)-N,N-dimethylamine, 0.13 mol 2-methacryloyloxyethyl phosphorylcholine, 0.4 mol 1-vinyl-3-ethylimidazolium bromide, 15.22 g ammonium dihydrogen phosphate, and 1450 g deionized water were added in sequence, stirred evenly, and the pH was adjusted to 7-8 with 13 wt% ammonia water;

[0053] (2) adding an initiator solution to a high-position dropping tank, wherein the initiator solution is 9.93 g of sodium persulfate and 3.31 g of sodium sulfite dissolved in 88.63 g of deionized water, and slowly adding the solution dropwise to the reactor. The initiator addition time is controlled within 70 min. After the addition is completed, stirring is performed for 35 min, and the temperature is continuously raised to 52° C., kept at this temperature for 1.6 h, and then cooled to below 40° C. The pH is adjusted to 7-8 with 10 wt % ammonia water to obtain a viscous liquid;

[0054] (3) The viscous liquid was dried and granulated into particles with a diameter of 0.4-1 mm using a granulator to obtain the product demulsifier M5.

[0055] Example 6

[0056] (1) The reactor and pipelines were purged with nitrogen at a ventilation rate of 2500 ml / L. After 7 minutes, the ventilation rate was adjusted to 180 ml / L. The nitrogen atmosphere was maintained throughout the subsequent synthesis process. 1 mol N-(4-vinylbenzyl)-N,N-dimethylamine, 0.15 mol 2-methacryloyloxyethyl phosphorylcholine, 0.3 mol 1-vinyl-3-ethylimidazolium bromide, 14.33 g disodium hydrogen phosphate, and 1500 g deionized water were added in sequence, stirred evenly, and the pH was adjusted to 7-8 with 14 wt% ammonia water;

[0057] (2) Add an initiator solution to the high-position drop tank. The initiator solution is 8.42 g of potassium persulfate and 4.21 g of sodium sulfite dissolved in 91.44 g of deionized water. Slowly add the initiator solution dropwise to the reactor. The initiator addition time is controlled within 90 min. After the addition is completed, stir for 32 min, continue to heat to 55 ° C, keep the temperature for reaction for 1.8 h, cool to below 40 ° C, and adjust the pH to 7-8 with 12 wt% ammonia water to obtain a viscous liquid.

[0058] (3) The viscous liquid was dried and granulated into particles with a diameter of 0.4-1 mm using a granulator to obtain the product demulsifier M6.

[0059] Example 7

[0060] (1) The reactor and pipelines were purged with nitrogen at a ventilation rate of 2200 ml / L. After 5 minutes, the ventilation rate was adjusted to 200 ml / L. The nitrogen atmosphere was maintained throughout the subsequent synthesis process. 1 mol N-(4-vinylbenzyl)-N,N-dimethylamine, 0.18 mol 2-methacryloyloxyethyl phosphorylcholine, 0.5 mol 1-vinyl-3-ethylimidazolium bromide, 12.11 g dipotassium hydrogen phosphate, and 1580 g deionized water were added in sequence, stirred evenly, and the pH was adjusted to 7-8 with 12 wt% ammonia water;

[0061] (2) Add an initiator solution to the high-position drop tank. The initiator solution is 10.11 g of potassium persulfate and 4.33 g of sodium sulfite dissolved in 100.72 g of deionized water. Slowly add the initiator solution dropwise to the reactor. The initiator addition time is controlled within 80 min. After the addition is completed, stir for 36 min, continue to heat to 60 ° C, keep the temperature for reaction for 1.7 h, cool to below 40 ° C, and adjust the pH to 7-8 with 13 wt% ammonia water to obtain a viscous liquid.

[0062] (3) The viscous liquid was dried and granulated into particles with a diameter of 0.4-1 mm using a granulator to obtain the product demulsifier M7.

[0063] Example 8

[0064] (1) The reactor and pipelines were purged with nitrogen at a ventilation rate of 2300 ml / L. After 10 min, the ventilation rate was adjusted to 150 ml / L. The nitrogen atmosphere was maintained throughout the subsequent synthesis process. 1 mol N-(4-vinylbenzyl)-N,N-dimethylamine, 0.2 mol 2-methacryloyloxyethyl phosphorylcholine, 0.5 mol 1-vinyl-3-ethylimidazolium bromide, 10.4 g diammonium hydrogen phosphate, and 1610 g deionized water were added in sequence, stirred evenly, and the pH was adjusted to 7-8 with 10 wt% ammonia water;

[0065] (2) Add an initiator solution to the high-position drop tank. The initiator solution is 11.3 g of ammonium persulfate and 4.8 g of sodium sulfite dissolved in 130.44 g of deionized water. Slowly add the initiator solution dropwise to the reactor. The initiator addition time is controlled within 60 min. After the addition is completed, stir for 38 min, continue to heat to 50 ° C, keep the temperature for reaction for 1.5 h, cool to below 40 ° C, and adjust the pH to 7-8 with 15 wt% ammonia water to obtain a viscous liquid.

[0066] (3) The viscous liquid was dried and granulated into particles with a diameter of 0.4-1 mm using a granulator to obtain the product demulsifier M8.

[0067] Example 9: Evaluation of oil removal effect

[0068] Water sample: produced water from an oil well in an oil field, oil content: 965 mg / L, suspended solids: 247 mg / L, temperature: 80°C, mineralization: 25600 mg / L.

[0069] Evaluation method: Add 1000ml of produced water to a series of beakers, followed by different concentrations of demulsifiers. Stir at 100rpm for 60s, let stand for 15min, remove the lower layer of water to test the oil content, and calculate the oil removal rate.

[0070] Concentrations of the present invention: 3, 5, 8 mg / L.

[0071] Comparative demulsifier: Thg-A demulsifier from Tianjin Wanfeng Technology and Trade Development Co., Ltd. was used. The experimental results are shown in Table 1.

[0072] Table 1 Demulsifier oil removal test results (oil removal rate, %)

[0073]

[0074]

[0075] As can be seen from Table 1: 1-8 The oil removal rate of the oil removal agent M in the present invention is 87% or more when the concentration is 3 mg / L, and the highest is 91.3%. The oil removal rate of Thg-A in the present invention is 71% when the concentration is 3 mg / L. 1-8 The oil removal rate of the oil removal agent M in the present invention is more than 91% when the concentration is 5 mg / L, and the highest is 96.1%. The oil removal rate of Thg-A in the present invention is 78.9% when the concentration is 5 mg / L. 1-8 When the concentration is 8 mg / L, the oil removal rate reaches over 98%, and the highest reaches 99.5%. When the concentration is 8 mg / L, the oil removal rate of Thg-A is 85.6%, which is significantly lower than that of the present invention.

[0076] Example 10 Evaluation of flocculation effect

[0077] Water sample: produced water from an oil well in an oil field, oil content: 965 mg / L, suspended solids: 247 mg / L, temperature: 80°C, mineralization: 25600 mg / L.

[0078] Evaluation method: Reference: Q / SH10201961-2018 "General Technical Conditions for Deoilers for Oilfield Produced Water Treatment".

[0079] Concentrations of the present invention: 3, 5, 8 mg / L.

[0080] Comparative demulsifier: Thg-A demulsifier from Tianjin Wanfeng Technology and Trade Development Co., Ltd. was used. The experimental results are shown in Table 2.

[0081] Table 2 Demulsifier flocculation test results (flocculation rate, %)

[0082] Degreaser 3mg / L,% 5mg / L,% 8mg / L,% <![CDATA[M1]]> 84.3 88.7 95.1 <![CDATA[M2]]> 83.8 88.5 95.9 <![CDATA[M3]]> 85.3 88.1 96.3 <![CDATA[M4]]> 85.4 88.9 96.8 <![CDATA[M5]]> 85.7 90.8 96.7 <![CDATA[M6]]> 85.5 90.8 97.0 <![CDATA[M7]]> 86 91 97.3 <![CDATA[M8]]> 85.3 91.5 97.6 Thg-A 42.3 59.6 75.3

[0083] As can be seen from Table 2: 1-8 The flocculation rate was over 83% when the concentration was 3 mg / L, and the highest was 86%. The flocculation rate of Thg-A was 42.3% when the concentration was 3 mg / L. The demulsifier M 1-8 The flocculation rate was over 88% when the concentration was 5 mg / L, and the highest was 91.5%. The flocculation rate of Thg-A was 59.6% when the concentration was 5 mg / L. 1-8 When the concentration was 8 mg / L, the flocculation rate was over 95%, with the highest reaching 97.6%. However, when the concentration was 8 mg / L, the flocculation rate of Thg-A was 75.3%, which was significantly lower than that of the present invention.

[0084] Example 11 Evaluation of Sterilization Effect

[0085] Water sample: reinjection water from a joint station in an oil field, SRB content: 1300 / mL, temperature: 73℃, mineralization: 17900mg / L.

[0086] 100 ml of water sample from a joint station of an oil production plant in Shengli Oilfield was added to a series of narrow-necked bottles, and different concentrations of the present invention were added, shaken, placed in a 73°C oven, and sampled after 1 hour. The remaining bacterial content was detected by the extinction dilution method, and the sterilization rate was calculated.

[0087] Concentrations of the present invention: 10, 20, 30 mg / L.

[0088] Comparative fungicide: dodecyldimethylbenzyl ammonium chloride (1227).

[0089] The experimental results are shown in Table 3.

[0090] Table 3 Demulsifier SRB sterilization test results (sterilization rate, %)

[0091] fungicides 10mg / L,% 20mg / L,% 30mg / L,% <![CDATA[M1]]> 99 99.8 100 <![CDATA[M2]]> 91.1 99.3 100 <![CDATA[M3]]> 93.3 99.3 100 <![CDATA[M4]]> 98.5 100 100 <![CDATA[M5]]> 93.3 99.6 100 <![CDATA[M6]]> 90 95.5 100 <![CDATA[M7]]> 97.7 100 100 <![CDATA[M8]]> 95.4 99.9 100 1227 15.4 46.2 92.5

[0092] As can be seen from Table 3: 1-8 The sterilization rate of the demulsifier M in the present invention is more than 90% when the concentration is 10 mg / L, and the highest is 98.5%. The sterilization rate of 1227 in the present invention is 15.4% when the concentration is 10 mg / L. 1-8 The sterilization rate of the demulsifier M of the present invention is more than 95% when the concentration is 20 mg / L, and the highest is 100%; while the sterilization rate of 1227 is 46.2% when the concentration is 20 mg / L; 1-8 The sterilization rate of 1227 at a concentration of 30 mg / L reached 100%, while the sterilization rate of 1227 at a concentration of 30 mg / L was 92.5%, which was significantly lower than that of the present invention.

Claims

1. A method for preparing a multifunctional polymer demulsifier, characterized in that: The specific steps of the preparation method are as follows: (1) Purge the reactor and pipelines with nitrogen at a ventilation rate of 2000-2500 ml / L. After 5-10 minutes, adjust the ventilation rate to 100-200 ml / L. Maintain a nitrogen atmosphere throughout the later synthesis process. Add N-(4-vinylbenzyl)-N,N-dimethylamine, 2-methacryloyloxyethyl phosphorylcholine, 1-vinyl-3-ethylimidazolium bromide, buffer salt, and deionized water in sequence, stir evenly, and adjust the pH to 7-8 with 10-15 wt% ammonia water; (2) Add the initiator solution to the high-position dropping tank and slowly add it dropwise into the reactor. The initiator addition time is controlled at 60-90 min. After the addition is completed, stir for 30-40 min, continue to heat to 50-60 ° C, keep the temperature for reaction for 1-2 h, cool to below 40 ° C, and adjust the pH to 7-8 with 10-15 wt% ammonia water to obtain a viscous liquid; (3) The viscous liquid is dried and granulated into particles with a diameter of 0.4-1 mm using a granulator to obtain a demulsifier product.

2. The method for preparing a multifunctional polymer demulsifier according to claim 1, characterized in that: Based on 1 mol part of N-(4-vinylbenzyl)-N,N-dimethylamine, the amounts of 2-methacryloyloxyethyl phosphorylcholine and 1-vinyl-3-ethylimidazolium bromide are 0.05-0.2 mol parts and 0.3-0.8 mol parts, respectively.

3. The method for preparing a multifunctional polymer demulsifier according to claim 2, characterized in that: Based on 1 mol part of N-(4-vinylbenzyl)-N,N-dimethylamine, the amounts of 2-methacryloyloxyethyl phosphorylcholine and 1-vinyl-3-ethylimidazolium bromide are 0.1-0.15 mol parts and 0.3-0.5 mol parts, respectively.

4. The method for preparing a multifunctional polymer demulsifier according to claim 1, characterized in that: The buffer salt described in step (1) is one of sodium dihydrogen phosphate, potassium dihydrogen phosphate, ammonium dihydrogen phosphate, disodium hydrogen phosphate, dipotassium hydrogen phosphate, and diammonium hydrogen phosphate, and the weight ratio of the buffer salt to N-(4-vinylbenzyl)-N,N-dimethylamine is 0.05-0.1:

1.

5. The method for preparing a multifunctional polymer demulsifier according to claim 1, characterized in that: The initiator described in step (2) is an azo compound system or a redox system, and the weight ratio of the initiator to N-(4-vinylbenzyl)-N,N-dimethylamine is 0.02-0.1:

1.

6. The method for preparing a multifunctional polymer demulsifier according to claim 5, characterized in that: The azo compound system is azobisisobutyronitrile toluene or azobisisoheptylnitrile toluene.

7. The method for preparing a multifunctional polymer demulsifier according to claim 5, characterized in that: The redox system is a mixture of persulfate and sodium sulfite, and the mass ratio of persulfate to sodium sulfite is 2-3:

1.

8. The method for preparing a multifunctional polymer demulsifier according to claim 7, characterized in that: The persulfate is one of sodium persulfate, ammonium persulfate and potassium persulfate.

9. A multifunctional polymer demulsifier, characterized in that: The molecular structural formula of the demulsifier is as follows: Where, x = 10000-100000; y＝1000-10000； z＝5000-50000。 10. A multifunctional polymer demulsifier according to claim 9, characterized in that: The viscosity average molecular weight of the demulsifier is 5,000,000-20,000,000.

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