A bactericidal defoamer for foam drainage and its preparation method

Abstract

The present invention belongs to the technical field of oil and gas development, and particularly relates to a bactericidal defoaming agent for foam drainage and a preparation method thereof. Its components include: alkynediol polyether modified silicone oil, polyoxyethylene polyoxypropylene pentaerythritol ether, modified nano-silica, emulsifier, co-solvent, benzyl quaternary ammonium salt disinfectant, pyrimidineamine bactericide and water. The preparation method includes: heating and stirring the alkynediol polyether modified silicone oil, adding the modified nano-silica and stirring, cooling and reducing the stirring speed, adding the polyoxyethylene polyoxypropylene pentaerythritol ether, and continuing to stir to obtain intermediate product A; adding water to another reaction kettle, heating and stirring, then adding the emulsifier, co-solvent, benzyl quaternary ammonium salt disinfectant, pyrimidineamine bactericide, stirring to obtain intermediate product B and then heating up; adding intermediate product A to intermediate product B and stirring to obtain the product. This bactericidal defoaming agent for foam drainage has multiple functions of sterilization and defoaming, achieving multiple effects with one agent.

Description

Technical Field

[0001] The present invention belongs to the technical field of oil and gas development, and particularly relates to a bactericidal defoaming agent for foam drainage and a preparation method thereof. Background Technique

[0002] During the production process of oil and gas wells and shale gas wells, since the liquid in the wellbore cannot be continuously carried out of the wellhead, the liquid accumulates at the bottom of the well to form bottom-hole liquid accumulation. The bottom-hole liquid accumulation will increase the bottom-hole back pressure, limit the production capacity of the well, lead to a reduction in the production of oil and gas wells and shale gas wells, and even cause a production shutdown phenomenon. At the same time, a large number of bacteria are contained in the accumulated liquid, which is prone to cause bacterial corrosion problems.

[0003] Foam drainage is a commonly used measure to remove bottom-hole liquid accumulation, which has the advantages of low cost and simple process. Through this measure, the bottom-hole liquid accumulation is converted into low-density foam and carried to the surface pipeline. To prevent the foam from entering the subsequent production process, a defoaming agent needs to be added to the surface pipeline to defoam the foam carried to the surface and prevent the foam from overflowing the tower.

[0004] The defoaming agents provided by the prior art mainly contain methyl silicone oil, polymer silicone oil, etc. They have poor dilution stability, are prone to water-oil separation during actual use, and thus cause problems such as floating oil blockage. The defoaming effect is average, they do not have multiple functions such as defoaming and sterilization, and the preparation process is relatively complex, which is not suitable for industrial application. Summary of the Invention

[0005] The purpose of the present invention is to provide a bactericidal defoaming agent for foam drainage and a preparation method thereof, so as to solve the problems of poor stability and easy generation of floating oil blockage existing in the defoaming agents in the prior art, and it has a sterilization function and a more comprehensive function. The defoaming agent provided by the present invention has a very strong defoaming function, good sterilization effect, strong practicability, and a wide range of applications.

[0006] The present invention provides a bactericidal defoaming agent for foam drainage, which comprises the following components in mass percentage:

[0007] 25-35% of alkynediol polyether modified silicone oil; the silicone oil main chain of the alkynediol polyether modified silicone oil has an extremely low surface tension (about 20-25 mN / m), which can quickly spread to the gas-liquid interface and form a local low surface tension region, causing local thinning of the foam liquid film based on the Marangoni effect; the hydrophilic end of the alkynediol part interacts with water through hydrogen bonds, enhancing the dispersibility in the polar system, and the polyether chain segment (such as EO / PO) adjusts the hydrophilic-hydrophobic balance and improves the compatibility with the complex system, so that the defoaming effect on the foam liquid can be achieved.

[0008] 10 - 15% of polyoxyethylene polyoxypropylene pentaerythritol ether. Further, the average relative molecular mass of the polyoxyethylene polyoxypropylene pentaerythritol ether is preferably 3000 - 8000 g / mol; the preferred average relative molecular mass has better homogeneity and better compatibility with other components. The polyoxyethylene end (EO) of the polyoxyethylene polyoxypropylene pentaerythritol ether provides hydrophilicity, the polyoxypropylene end (PO) gives hydrophobicity, and the four-arm structure of pentaerythritol forms a steric hindrance, enhancing the penetration ability of the foam liquid film and accelerating foam rupture.

[0009] 2 - 4% of modified nano-silica; the modified nano-silica has high hydrophobicity, which can promote the rapid dispersion of the defoamer during use, thereby improving the defoaming efficiency and enhancing the dilution stability of the defoamer.

[0010] 2 - 5% of emulsifier, and the emulsifier is one or more of polyoxyethyl polyoxypropyl glycerol ether, polyoxyethyl glycerol ether, and polyoxypropyl glycerol ether; the emulsifier enables the rapid formation of a homogeneous emulsion of alkynediol polyether modified silicone oil and polyoxyethylene polyoxypropylene pentaerythritol ether with the aqueous phase, making the defoamer disperse evenly, with better defoaming effect and convenient for on-site filling.

[0011] 1 - 2% of co-solvent, and the co-solvent is one or more of ethylene glycol monon-propyl ether, ethylene glycol monomethyl ether, ethylene glycol monoethyl ether, ethylene glycol monobutyl ether, and diethylene glycol butyl ether; the co-solvent can improve the compatibility of alkynediol polyether modified silicone oil and polyoxyethylene polyoxypropylene pentaerythritol ether that are insoluble in water, and can reduce the local surface tension of the foam, promoting foam rupture.

[0012] 0.5 - 2% of benzyl quaternary ammonium salt disinfectant, and the benzyl quaternary ammonium salt disinfectant is one or more of dodecyl dimethyl benzyl ammonium chloride, dodecyl dimethyl benzyl ammonium bromide, octadecyl dimethyl benzyl ammonium chloride, octadecyl dimethyl benzyl ammonium bromide, benzyl triethyl ammonium chloride, and benzyl triethyl ammonium bromide; the benzyl quaternary ammonium salt disinfectant has a broad-spectrum bactericidal effect and can destroy the cell membrane structure of bacteria.

[0013] 0.01 - 0.1% of pyrimidine amine fungicide, and the pyrimidine amine fungicide is one or more of pyrimethanil, N-phenylpyridin-4-amine, N-(2-methyl-5-nitrophenyl)-4-(3-pyridyl)-2-pyrimidinamine, and 2-(3-pyridyl)-4-pyrimidinamine; the pyrimidine amine fungicide can efficiently block the growth of bacteria and inhibit the secretion of bacterial infection enzymes, thereby synergistically enhancing the effect with the benzyl quaternary ammonium salt disinfectant to achieve high-efficiency sterilization without generating drug resistance.

[0014] The balance is water.

[0015] The defoamer for foam drainage provided by this application has an original formula, components and dosage created by the applicant. It has good compatibility, synergizes with each other, achieves excellent defoaming and bactericidal effects, and at the same time has strong dilution stability, with broad market prospects.

[0016] The principle is that the alkynediol polyether modified silicone oil, as the main agent of the defoamer, forms a synergistic effect with polyoxyethylene polyoxypropylene pentaerythritol ether, significantly enhancing the defoaming effect of the defoamer. Specifically, polyoxyethylene polyoxypropylene pentaerythritol ether can adsorb on the interface to form a "loose layer", forming a gradient with the dense adsorption layer of the alkynediol polyether modified silicone oil, accelerating the drainage of the liquid film and improving the defoaming effect; on the other hand, the alkynediol polyether modified silicone oil is preferentially adsorbed on the gas-liquid interface, occupying the interface position of the foaming agent (such as surfactant). Subsequently, polyoxyethylene polyoxypropylene pentaerythritol ether inserts into the gap of the alkynediol polyether modified silicone oil layer through a multi-branched structure, further destroying the continuity of the interface film. Finally, the hydrophobic chain (PO) of polyoxyethylene polyoxypropylene pentaerythritol ether promotes the directional drainage of water in the liquid film, and the spreading effect of the alkynediol polyether modified silicone oil expands the drainage channel. The two work together to accelerate the rupture of the liquid film, achieving the effect of high-efficiency defoaming.

[0017] Furthermore, among the above components, the preparation method of the alkynediol polyether modified silicone oil is as follows:

[0018] S11. By mass, add 3-5 parts of alkynediol and 0.15-0.15 parts of alcohol base into the reaction kettle and continuously stir, and introduce inert gas to displace for 30-60 min;

[0019] The alkynediol is one or more of 1,4-butynediol, dimethyloctynediol, tetramethyldecynediol, 1,4-pentadiyn-3-ol; the alcohol base is at least one of potassium ethoxide and sodium ethoxide. Introducing inert gas can remove active gases such as oxygen in the reaction kettle, avoiding interference of active gases such as oxygen on subsequent reactions; the inert gas used in this application is preferably nitrogen, and other inert gases such as helium can also be introduced according to needs, which is not limited here.

[0020] S12. Add 18-26 parts of liquid alkylene oxide into the reaction kettle, continue to introduce inert gas until the pressure in the reaction kettle is 0.8-1.0 MPa, and at the same time heat the reaction system to 85-95 °C, and carry out ring-opening polymerization reaction for 1-2 h; the liquid alkylene oxide is one or more of propylene oxide, 1,2-epoxybutane, 1,2-epoxypentane.

[0021] S13. Cool the reaction system to room temperature, and reduce the pressure in the reaction kettle to atmospheric pressure.

[0022] S14. Add 25 - 35 parts of hydrogen-containing silicone oil and 0.001 - 0.002 parts of catalyst into the reaction kettle, heat to 90 - 100 °C, and carry out alkynyl addition reaction for 2 - 4 h; the hydrogen-containing silicone oil is at least one of methyl hydrogen-containing silicone oil, ethyl hydrogen-containing silicone oil, and phenyl hydrogen-containing silicone oil; the catalyst is at least one of bis[(α,α,α′,α′-tetramethyl-1,3-benzenedipropionic acid)rhodium] and di-rhodium tetraacetate.

[0023] S15. Cool the reaction system to room temperature and stop stirring to obtain alkynediol polyether modified silicone oil.

[0024] In this application, the one-pot method is used to prepare alkynediol polyether modified silicone oil. First, liquid epoxy alkane is used to open the ring and polymerize with alkynediol to obtain alkynediol ether. The process is simple and easy to control, avoiding the safety risks caused by using gaseous epoxy alkane. Then, the obtained diol ether and hydrogen-containing silicone oil with active Si-H bonds in the molecular structure are subjected to alkynyl addition reaction under the catalyst to obtain alkynediol polyether modified silicone oil. The whole preparation process is simple to operate, does not involve gas filling, has a high safety factor, and is easy to control, which better meets the requirements of industrial production.

[0025] Further, in the above components, the preparation method of modified nano-silica is as follows:

[0026] S21. Weigh 5 - 8 parts of nano-silica and add it to 80 - 120 parts of dispersant, and stir evenly at a constant speed to make it fully mixed; the stirring speed is preferably 300 - 800 rpm, and the stirring time is preferably 10 - 30 min; the dispersant is one or more of n-butanol, toluene, and ethylene glycol; the nano-silica preferably has a specific surface area of 100 - 400 ㎡ / g, and with a preferred specific surface area, the dispersibility is better.

[0027] S22. Place the liquid obtained in step S21 under ultrasonic waves for ultrasonic dispersion. The dispersion time is preferably 15 - 25 min, and the ultrasonic frequency is preferably 120 - 200 KHz to obtain nano-silica dispersion liquid.

[0028] S23. Continue to stir at a speed of 300 - 800 rpm, place the nano-silica dispersion liquid in the reaction kettle, add 0.5 - 0.8 parts of coupling agent to the reaction kettle, heat the reaction system to 75 - 95 °C and react for 5 - 7 h, then stop stirring and cool to room temperature to obtain a modified nano-silica mixture containing impurities; the coupling agent is one or more of N-(β-aminoethyl)-γ-aminopropylmethyldimethoxysilane, 3-aminopropyltriethoxysilane, and N-(β-aminoethyl)-γ-aminopropyltrimethoxysilane.

[0029] S24. Centrifuge the modified nano-silica mixture containing impurities at a centrifuge speed preferably of 10,000 - 20,000 rpm, remove the upper liquid, and obtain the lower precipitate.

[0030] S25. Wash, dry, and grind the lower precipitate to obtain white and fluffy modified nano-silica. The liquid for washing is preferably anhydrous ethanol, and the number of washing times is preferably 2 - 4 times.

[0031] The present application also provides a preparation method of a bactericidal defoamer for foam drainage, specifically as follows:

[0032] S1. By mass percentage, add 25 - 35% of alkynediol polyether modified silicone oil to the reaction kettle, heat to 70 - 90 °C and stir at a speed of 300 - 600 rpm; then slowly add 2 - 4% of modified nano-silica and continue stirring for 70 - 90 min; then cool down to below 60 °C, and then add 10 - 15% of polyoxyethylene polyoxypropylene pentaerythritol ether with an average relative molecular mass of 3000 - 8000 g / mol, and continue stirring for 30 - 60 min to obtain intermediate product A; slowly adding modified nano-silica can avoid its condensation or aggregation and make it fully and evenly dispersed in the liquid;

[0033] S2. Add the remaining amount of water by mass percentage to another reaction kettle, heat to 40 - 60 °C and stir at a speed of 200 - 400 rpm, then add 2 - 5% of emulsifier, 1 - 2% of cosolvent, 0.5 - 2% of benzyl quaternary ammonium salt disinfectant, 0.01 - 0.1% of pyrimidine amine fungicide, and stir for 30 - 60 min to obtain intermediate product B;

[0034] S3. Under stirring at 40 - 60 °C and a speed of 200 - 400 rpm, add intermediate product A to intermediate product B, continue stirring for 30 - 60 min, and then cool down to room temperature to obtain the bactericidal defoamer for foam drainage.

[0035] In step S1, the stirring is set at 70 - 90 °C because this temperature range can promote the uniform mixing of alkynediol polyether modified silicone oil and modified nano-silica as soon as possible, facilitating the formation of a homogeneous state; cooling down to below 60 °C ensures that after intermediate product A and intermediate product B are mixed, the temperature is the same as or lower than that of intermediate product B, avoiding the problem of cosolvent volatilization caused by too high temperature, ensuring the component stability of the bactericidal defoamer for foam drainage and not affecting its efficacy.

[0036] Furthermore, the temperature after cooling in step S1 is not higher than the temperature in step S2. For example, if the temperature in step S2 is 40 °C, then the temperature after cooling in step S1 is 40 °C or a lower value, such as 15 °C, 30 °C, etc.

[0037] Compared with the prior art, the beneficial effects of the bactericidal defoamer for foam drainage and its preparation method provided by the present invention are as follows:

[0038] 1. The defoamer provided in this application has dual functions of sterilization and defoaming, achieving multiple effects with one agent. The sterilization rate reaches 100% and no drug resistance will be generated. The defoaming effect is excellent, the initial defoaming rate reaches 99.5% - 100%, and the defoaming rate reaches 100% after 3 minutes.

[0039] 2. The defoamer provided in this application has good dilution stability, and there is no floating oil, precipitation or floccules during use, avoiding the problem of floating oil blockage.

[0040] 3. The preparation method of the defoamer provided in this application has a simple process, is easy to control, has a high safety factor, and is more suitable for industrial application. Specific Embodiments

[0041] To make the objectives, technical solutions and advantages of this application clearer and more understandable, the following will further elaborate on this application in combination with embodiments. The illustrative embodiments of this application and their descriptions are only used to explain this application and do not limit this application. Any product that is the same as or similar to this application obtained by anyone under the inspiration of this application or by combining the features of this application with those of other prior arts falls within the protection scope of this application.

[0042] For the specific experimental steps or conditions not specified in the embodiments, the operations or conditions of the conventional experimental steps described in the prior art in this field can be followed. All reagents and other instruments not indicating the manufacturer can be obtained as conventional reagent products through commercial purchase.

[0043] Example 1:

[0044] The bactericidal defoamer for foam drainage provided in Example 1 includes the following components in mass percentage: 25% of alkynediol polyether modified silicone oil, 10% of polyoxyethylene polyoxypropylene pentaerythritol ether with an average relative molecular mass of 3000 g / mol, 2% of modified nano-silica, 2% of polyoxyethyl polyoxypropyl glycerol ether, 1% of ethylene glycol monon-propyl ether, 0.5% of dodecyl dimethyl benzyl ammonium chloride, 0.01% of pyrimethanil, and the balance is water.

[0045] This bactericidal defoamer for foam drainage is prepared by the following method:

[0046] S1. Add 25 kg of alkynediol polyether modified silicone oil to the reaction kettle, heat it to 70 °C and stir at a speed of 300 rpm; then slowly add 2 kg of modified nano-silica, and continue stirring for 70 min; then cool down to 40 °C, and add 10 kg of polyoxyethylene polyoxypropylene pentaerythritol ether with an average relative molecular mass of 3000 g / mol, and continue stirring for 30 min to obtain intermediate product A;

[0047] S2. Add 59.49 kg of water to another reaction kettle, heat it to 40 °C and stir at a speed of 200 rpm, then add 2 kg of polyoxyethylenepolyoxypropylene glycerol ether, 1 kg of ethylene glycol monon-propyl ether, 0.5 kg of dodecyldimethylbenzylammonium chloride, and 0.01 kg of pyrimethanil, and stir for 30 min to obtain intermediate product B;

[0048] S3. Under stirring at 40 °C and a speed of 200 rpm, add intermediate product A to intermediate product B, continue stirring for 30 min, and then cool down to room temperature to obtain the bactericidal defoamer for foam drainage.

[0049] In addition, the preparation method of the alkynediol polyether modified silicone oil in the formula is as follows:

[0050] S11. By mass, add 3 parts of 1,4-butynediol and 0.05 part of potassium ethoxide to the reaction kettle and continuously stir, and introduce nitrogen for replacement for 30 min;

[0051] S12. Add 18 parts of propylene oxide to the reaction kettle, continue to introduce nitrogen until the pressure in the reaction kettle is 0.8 MPa, and at the same time heat the reaction system to 85 °C for ring-opening polymerization reaction for 1 h;

[0052] S13. Cool the reaction system to room temperature, and reduce the pressure in the reaction kettle to normal pressure;

[0053] S14. Add 25 parts of methylhydrogen silicone oil and 0.001 part of bis[(α,α,α′,α′-tetramethyl-1,3-benzenedipropanoic acid) rhodium] to the reaction kettle, heat it to 90 °C, and carry out alkynyl addition reaction for 2 h;

[0054] S15. Cool the reaction system to room temperature and stop stirring to obtain the alkynediol polyether modified silicone oil.

[0055] The preparation method of the modified nano-silica in the formula is as follows:

[0056] S21. By mass, weigh 5 parts of nano-silica with a specific surface area of 100 m² / g and add it to 80 parts of n-butanol, and stir at a speed of 300 rpm for 10 min to make it fully mixed evenly;

[0057] S22. Place the liquid obtained in step S21 under ultrasonic waves for ultrasonic dispersion for 15 min at an ultrasonic frequency of 120 KHz to obtain a nano-silica dispersion liquid.

[0058] S23. Place the nano-silica dispersion liquid in a reaction kettle. Under the stirring condition of 300 rpm, add 0.5 part of N-(β-aminoethyl)-γ-aminopropylmethyldimethoxysilane to the reaction kettle. Heat the reaction system to 75 °C and react for 5 h, then stop stirring and cool to room temperature to obtain a modified nano-silica mixture containing impurities.

[0059] S24. Centrifuge the modified nano-silica mixture containing impurities at a centrifuge speed of 10,000 rpm, remove the upper-layer liquid to obtain the lower-layer precipitate.

[0060] S25. Wash the lower-layer precipitate with absolute ethanol twice, dry and grind it to obtain white and fluffy modified nano-silica.

[0061] Example 2:

[0062] The bactericidal defoamer for foam drainage provided in Example 2 comprises the following components in mass percentages: 30% of alkynediol polyether modified silicone oil, 12.5% of polyoxyethylene polyoxypropylene pentaerythritol ether with an average relative molecular mass of 5000 g / mol, 3% of modified nano-silica, 3.5% of polyoxyethyl glycerol ether, 1.5% of ethylene glycol monomethyl ether, 1.25% of dodecyl dimethyl benzyl ammonium bromide, 0.05% of N-phenylpyridin-4-amine, and the balance is water.

[0063] The bactericidal defoamer for foam drainage is prepared by the following method:

[0064] S1. Add 30 kg of alkynediol polyether modified silicone oil to a reaction kettle, heat it to 80 °C and keep stirring at a speed of 400 rpm; then slowly add 3 kg of modified nano-silica and continue stirring for 80 min; then cool down to 30 °C, and add 12.5 kg of polyoxyethylene polyoxypropylene pentaerythritol ether with an average relative molecular mass of 5000 g / mol and continue stirring for 45 min to obtain intermediate product A.

[0065] S2. Add 48.2 kg of water to another reaction kettle, heat it to 50 °C and keep stirring at a speed of 300 rpm, then add 3.5 kg of polyoxyethyl glycerol ether, 1.5 kg of ethylene glycol monomethyl ether, 1.25 kg of dodecyl dimethyl benzyl ammonium bromide, 0.05 kg of N-phenylpyridin-4-amine, and stir for 45 min to obtain intermediate product B.

[0066] S3. Under stirring at 50 °C and 300 rpm, add intermediate product A to intermediate product B, continue stirring for 45 min, and then cool to room temperature to obtain the bactericidal defoamer for foam drainage.

[0067] In addition, the preparation method of the alkynediol polyether modified silicone oil in the formula is as follows:

[0068] S11. By mass, add 5 parts of dimethyl octynediol and 0.15 part of sodium ethoxide to the reaction kettle and stir continuously. Purge with nitrogen for 60 min.

[0069] S12. Add 26 parts of 1,2-epoxybutane to the reaction kettle, continue purging with nitrogen until the pressure in the reaction kettle is 1.0 MPa, and at the same time heat the reaction system to 95 °C and carry out ring-opening polymerization reaction for 2 h.

[0070] S13. Cool the reaction system to room temperature and reduce the pressure in the reaction kettle to atmospheric pressure.

[0071] S14. Add 35 parts of phenyl hydrogen-containing silicone oil and 0.002 part of rhodium diacetate to the reaction kettle, heat to 100 °C, and carry out alkynyl addition reaction for 4 h.

[0072] S15. Cool the reaction system to room temperature and stop stirring to obtain the alkynediol polyether modified silicone oil.

[0073] The preparation method of the modified nano-silica in the formula is as follows:

[0074] S21. By mass, weigh 6.5 parts of nano-silica with a specific surface area of 250 m² / g and add it to 100 parts of toluene. Stir at 500 rpm for 20 min to mix it evenly.

[0075] S22. Place the liquid obtained in step S21 under ultrasonic waves for ultrasonic dispersion for 20 min, and the ultrasonic frequency is 160 KHz to obtain a nano-silica dispersion.

[0076] S23. Place the nano-silica dispersion in the reaction kettle. Under stirring at 500 rpm, add 0.65 part of N-(β-aminoethyl)-γ-aminopropyltrimethoxysilane to the reaction kettle. Heat the reaction system to 85 °C and react for 6 h, then stop stirring and cool to room temperature to obtain a modified nano-silica mixture containing impurities.

[0077] S24. Centrifuge the modified nano-silica mixture containing impurities at a centrifugal speed of 15000 rpm, remove the upper layer of liquid, and obtain the lower layer of precipitate.

[0078] S25. Wash the lower layer of precipitate with anhydrous ethanol 3 times, dry and grind to obtain white and fluffy modified nano-silica.

[0079] Example 3:

[0080] The bactericidal defoamer for foam drainage provided in Example 3 comprises components in the following mass percentages: 35% of alkynediol polyether modified silicone oil, 15% of polyoxyethylene polyoxypropylene pentaerythritol ether with an average relative molecular mass of 8000 g / mol, 4% of modified nano-silica, 5% of polyoxypropyl glycerol ether, 2% of ethylene glycol monoethyl ether, 2% of octadecyl dimethyl benzyl ammonium chloride, 0.1% of N-(2-methyl-5-nitrophenyl)-4-(3-pyridyl)-2-pyrimidinamine, and the balance is water.

[0081] The bactericidal defoamer for foam drainage is prepared by the following method:

[0082] S1. Add 35 kg of alkynediol polyether modified silicone oil to a reaction kettle, heat to 90 °C and stir at a rotation speed of 600 rpm; then slowly add 4 kg of modified nano-silica and continue stirring for 90 min; then cool down to 60 °C, and add 15 kg of polyoxyethylene polyoxypropylene pentaerythritol ether with an average relative molecular mass of 8000 g / mol, and continue stirring for 60 min to obtain intermediate product A;

[0083] S2. Add 36.9 kg of water to another reaction kettle, heat to 60 °C and stir at a rotation speed of 400 rpm, then add 5 kg of polyoxypropyl glycerol ether, 2 kg of ethylene glycol monoethyl ether, 2 kg of octadecyl dimethyl benzyl ammonium chloride, 0.1 kg of N-(2-methyl-5-nitrophenyl)-4-(3-pyridyl)-2-pyrimidinamine, and stir for 60 min to obtain intermediate product B;

[0084] S3. Under stirring at 60 °C and a rotation speed of 400 rpm, add intermediate product A to intermediate product B, continue stirring for 60 min and then cool down to room temperature to obtain the bactericidal defoamer for foam drainage.

[0085] In addition, the preparation method of the alkynediol polyether modified silicone oil in the formula is as follows:

[0086] S11. Add 4 parts by mass of tetramethyl decynediol, 0.05 part of potassium ethanolate, and 0.05 part of sodium ethanolate to a reaction kettle and continuously stir, and introduce nitrogen to displace for 45 min;

[0087] S12. Add 22 parts by mass of 1,2-epoxypentane to the reaction kettle, continue to introduce nitrogen until the pressure in the reaction kettle is 0.9 MPa, and at the same time heat the reaction system to 90 °C and carry out ring-opening polymerization reaction for 1.5 h;

[0088] S13. Cool the reaction system to room temperature and reduce the pressure in the reaction kettle to normal pressure;

[0089] S14. Add 30 parts of ethyl hydrogen silicone oil, 0.0007 part of bis[(α,α,α′,α′-tetramethyl-1,3-benzenedipropanoic acid) rhodium], and 0.0008 part of dirhodium tetraacetate into the reaction kettle, heat to 95 °C, and carry out the alkynyl addition reaction for 3 h;

[0090] S15. Cool the reaction system to room temperature and stop stirring to obtain alkynediol polyether modified silicone oil.

[0091] The preparation method of the modified nano-silica in the formula is as follows:

[0092] S21. Weigh 8 parts of nano-silica with a specific surface area of 400 m² / g and add it to 120 parts of ethylene glycol, stir at a speed of 800 rpm for 30 min to make it fully and evenly mixed;

[0093] S22. Place the liquid obtained in step S21 under ultrasonic waves for ultrasonic dispersion for 25 min, and the ultrasonic frequency is 200 KHz to obtain a nano-silica dispersion;

[0094] S23. Place the nano-silica dispersion in a reaction kettle, under the stirring condition of 800 rpm, add 0.8 part of 3-aminopropyltriethoxysilane to the reaction kettle, heat the reaction system to 95 °C and react for 7 h, then stop stirring and cool to room temperature to obtain a modified nano-silica mixture containing impurities;

[0095] S24. Centrifuge the modified nano-silica mixture containing impurities at a centrifugal speed of 20000 rpm, remove the upper layer of liquid to obtain the lower layer of precipitate;

[0096] S25. Wash the lower layer of precipitate with absolute ethanol 4 times, dry and grind it to obtain white and fluffy modified nano-silica.

[0097] Example 4:

[0098] The bactericidal defoamer for foam drainage provided in Example 4 includes the following components in mass percentage: 27% of alkynediol polyether modified silicone oil, 14% of polyoxyethylene polyoxypropylene pentaerythritol ether with an average relative molecular mass of 6000 g / mol, 2.5% of modified nano-silica, 2% of polyoxyethyl polyoxypropyl glycerol ether, 2% of polyoxyethyl glycerol ether, 1.5% of ethylene glycol monobutyl ether, 1% of octadecyl dimethyl benzyl ammonium bromide, 0.08% of 2-(3-pyridyl)-4-pyrimidinamine, and the balance is water.

[0099] The bactericidal defoamer for foam drainage is prepared by the following method:

[0100] S1. Add 27 kg of alkynediol polyether modified silicone oil to the reaction kettle, heat it to 75 °C and stir at a speed of 400 rpm; then slowly add 2.5 kg of modified nano-silica and continue stirring for 75 min; then cool down to 15 °C, and add 14 kg of polyoxyethylene polyoxypropylene pentaerythritol ether with an average relative molecular mass of 6000 g / mol, and continue stirring for 40 min to obtain intermediate product A;

[0101] S2. Add 49.92 kg of water to another reaction kettle, heat it to 45 °C and stir at a speed of 250 rpm, then add 2 kg of polyoxyethyl polyoxypropyl glycerol ether, 2 kg of polyoxyethyl glycerol ether, 1.5 kg of ethylene glycol monobutyl ether, 1 kg of octadecyl dimethyl benzyl ammonium bromide, and 0.08 kg of 2-(3-pyridyl)-4-pyrimidinamine, and stir for 40 min to obtain intermediate product B;

[0102] S3. Under stirring at 45 °C and a speed of 250 rpm, add intermediate product A to intermediate product B, continue stirring for 45 min, and then cool down to room temperature to obtain the bactericidal defoamer for foam drainage.

[0103] In addition, the preparation method of the alkynediol polyether modified silicone oil in the formula is as follows:

[0104] S11. By mass, add 3.5 parts of 1,4-pentadiyn-3-ol and 0.08 part of potassium ethoxide to the reaction kettle, and introduce nitrogen to displace for 40 min;

[0105] S12. Add 10 parts of propylene oxide and 10 parts of 1,2-epoxybutane to the reaction kettle, continue introducing nitrogen until the pressure in the reaction kettle is 0.85 MPa, and at the same time heat the reaction system to 88 °C for ring-opening polymerization reaction for 80 min;

[0106] S13. Cool the reaction system to room temperature and reduce the pressure in the reaction kettle to atmospheric pressure;

[0107] S14. Add 14 parts of methylhydrogen silicone oil, 14 parts of phenylhydrogen silicone oil, and 0.0012 part of bis[(α,α,α′,α′-tetramethyl-1,3-benzenedipropionic acid)rhodium] to the reaction kettle, heat it to 93 °C, and carry out alkynyl addition reaction for 2.5 h;

[0108] S15. Cool the reaction system to room temperature and stop stirring to obtain the alkynediol polyether modified silicone oil.

[0109] The preparation method of the modified nano-silica in the formula is as follows:

[0110] S21. Weigh 6 parts by mass of nano-silica with a specific surface area of 300 m² / g and add it to a mixed solution composed of 50 parts of n-butanol and 40 parts of toluene. Stir at a speed of 600 rpm for 15 min to make it fully and evenly mixed.

[0111] S22. Place the liquid obtained in step S21 under ultrasonic waves for ultrasonic dispersion for 18 min. The ultrasonic frequency is 150 KHz to obtain a nano-silica dispersion.

[0112] S23. Place the nano-silica dispersion in a reaction kettle. Under the stirring condition of 600 rpm, add 0.3 parts of N-(β-aminoethyl)-γ-aminopropylmethyldimethoxysilane and 0.3 parts of N-(β-aminoethyl)-γ-aminopropyltrimethoxysilane to the reaction kettle. Heat the reaction system to 80 °C and react for 5.5 h, then stop stirring and cool to room temperature to obtain a modified nano-silica mixture containing impurities.

[0113] S24. Centrifuge the modified nano-silica mixture containing impurities at a centrifugal speed of 12,000 rpm, remove the upper layer of liquid to obtain the lower layer of precipitate.

[0114] S25. Wash the lower layer of precipitate with anhydrous ethanol 3 times, dry and grind it to obtain white and fluffy modified nano-silica.

[0115] Example 5:

[0116] The bactericidal defoamer for foam drainage provided in Example 5 includes the following components in mass percentage: 30% of alkynediol polyether modified silicone oil, 13% of polyoxyethylene polyoxypropylene pentaerythritol ether with an average relative molecular mass of 4000 g / mol, 3.5% of modified nano-silica, 1% of polyoxyethyl polyoxypropyl glycerol ether, 1% of polyoxyethyl glycerol ether, 1% of polyoxypropyl glycerol ether, 1.8% of diethylene glycol butyl ether, 1.2% of benzyltriethylammonium chloride, 0.05% of pyrimethanil, 0.05% of N-phenylpyridin-4-amine, and the balance is water.

[0117] The bactericidal defoamer for foam drainage is prepared by the following method:

[0118] S1. Add 30 kg of alkynediol polyether modified silicone oil to a reaction kettle, heat to 85 °C and keep stirring at a speed of 500 rpm; then slowly add 3.5 kg of modified nano-silica and continue stirring for 85 min; then cool down to 55 °C, and add 13 kg of polyoxyethylene polyoxypropylene pentaerythritol ether with an average relative molecular mass of 4000 g / mol, and continue stirring for 50 min to obtain intermediate product A.

[0119] S2. Add 47.4 kg of water to another reaction kettle, heat it to 55 °C and keep stirring at a speed of 300 rpm. Then add 1 kg of polyoxyethyl polyoxypropyl glycerol ether, 1 kg of polyoxyethyl glycerol ether, 1 kg of polyoxypropyl glycerol ether, 1.8 kg of diethylene glycol butyl ether, 1.2 kg of benzyltriethylammonium chloride, 0.05 kg of pyrimethanil, and 0.05 kg of N-phenylpyridin-4-amine, and stir for 50 min to obtain intermediate product B;

[0120] S3. Under stirring at 55 °C and a speed of 300 rpm, add intermediate product A to intermediate product B, continue stirring for 55 min, and then cool down to room temperature to obtain the bactericidal defoamer for foam drainage.

[0121] In addition, the preparation method of the alkynediol polyether modified silicone oil in the formula is as follows:

[0122] S11. By mass, add 1.5 parts of 1,4-butynediol, 1.5 parts of dimethyloctynediol, 1.5 parts of tetramethyldecynediol, 0.06 part of potassium ethoxide, and 0.06 part of sodium ethoxide to the reaction kettle and keep stirring, and introduce nitrogen for replacement for 50 min;

[0123] S12. Add 8 parts of propylene oxide, 8 parts of 1,2-epoxybutane, and 8 parts of 1,2-epoxypentane to the reaction kettle, continue to introduce nitrogen until the pressure in the reaction kettle is 0.95 MPa, and at the same time heat the reaction system to 92 °C for ring-opening polymerization reaction for 100 min;

[0124] S13. Cool the reaction system to room temperature and reduce the pressure in the reaction kettle to atmospheric pressure;

[0125] S14. Add 11 parts of methylhydrogen silicone oil, 11 parts of phenylhydrogen silicone oil, 11 parts of ethylhydrogen silicone oil, 0.0009 part of bis[(α,α,α′,α′-tetramethyl-1,3-benzenedipropionic acid)rhodium], and 0.0009 part of dirhodium tetraacetate to the reaction kettle, heat to 98 °C, and carry out alkynyl addition reaction for 3.5 h;

[0126] S15. Cool the reaction system to room temperature and stop stirring to obtain the alkynediol polyether modified silicone oil.

[0127] The preparation method of the modified nano-silica in the formula is as follows:

[0128] S21. By mass, weigh 7 parts of nano-silica with a specific surface area of 200 m² / g and add it to a mixed solution composed of 30 parts of n-butanol, 30 parts of toluene, and 30 parts of ethylene glycol, and stir at a speed of 450 rpm for 20 min to make it fully mixed and uniform;

[0129] S22. Place the liquid obtained in step S21 under ultrasonic waves for ultrasonic dispersion for 22 min at an ultrasonic frequency of 180 KHz to obtain a nano-silica dispersion liquid;

[0130] S23. Place the nano-silica dispersion liquid in a reaction kettle. Under the stirring condition of 450 rpm, add 0.2 parts of N-(β-aminoethyl)-γ-aminopropylmethyldimethoxysilane, 0.2 parts of N-(β-aminoethyl)-γ-aminopropyltrimethoxysilane, and 0.2 parts of 3-aminopropyltriethoxysilane to the reaction kettle. Heat the reaction system to 90 °C and react for 6.5 h, then stop stirring and cool to room temperature to obtain a modified nano-silica mixture containing impurities;

[0131] S24. Centrifuge the modified nano-silica mixture containing impurities at a centrifuge speed of 18,000 rpm, remove the upper-layer liquid to obtain the lower-layer precipitate;

[0132] S25. Wash the lower-layer precipitate 4 times with anhydrous ethanol, dry and grind it to obtain white and fluffy modified nano-silica.

[0133] Example 6:

[0134] The bactericidal defoamer for foam drainage provided in Example 6 comprises the following components in mass percentage: 30% of alkynediol polyether modified silicone oil, 11% of polyoxyethylene polyoxypropylene pentaerythritol ether with an average relative molecular mass of 7000 g / mol, 2.5% of modified nano-silica, 1% of polyoxyethyl polyoxypropyl glycerol ether, 1.5% of polyoxyethyl glycerol ether, 1.5% of polyoxypropyl glycerol ether, 0.5% of ethylene glycol mononormal propyl ether, 0.5% of ethylene glycol monomethyl ether, 0.5% of ethylene glycol monobutyl ether, 0.5% of diethylene glycol butyl ether, 0.5% of dodecyl dimethyl benzyl ammonium chloride, 0.5% of octadecyl dimethyl benzyl ammonium bromide, 1% of benzyl triethyl ammonium bromide, 0.03% of pyrimethanil, 0.03% of N-phenylpyridin-4-amine, 0.02% of N-(2-methyl-5-nitrophenyl)-4-(3-pyridyl)-2-pyrimidinamine, 0.02% of 2-(3-pyridyl)-4-pyrimidinamine, and the balance is water.

[0135] The bactericidal defoamer for foam drainage is prepared by the following method:

[0136] S1. Add 30 kg of alkynediol polyether modified silicone oil to a reaction kettle, heat to 80 °C and maintain stirring at a speed of 400 rpm, then slowly add 2.5 kg of modified nano-silica and continue stirring for 80 min; then cool to 22 °C, and add 11 kg of polyoxyethylene polyoxypropylene pentaerythritol ether with an average relative molecular mass of 7000 g / mol, and continue stirring for 40 min to obtain intermediate product A;

[0137] S2. Add 48.4 kg of water to another reaction kettle, heat it to 50 °C and stir at a speed of 300 rpm. Then add 1 kg of polyoxyethyl polyoxypropyl glycerol ether, 1.5 kg of polyoxyethyl glycerol ether, 1.5 kg of polyoxypropyl glycerol ether, 0.5 kg of ethylene glycol monon-propyl ether, 0.5 kg of ethylene glycol monomethyl ether, 0.5 kg of ethylene glycol monobutyl ether, 0.5 kg of diethylene glycol butyl ether, 0.5 kg of dodecyl dimethyl benzyl ammonium chloride, 0.5 kg of octadecyl dimethyl benzyl ammonium bromide, 1 kg of benzyl triethyl ammonium bromide, 0.03 kg of pyrimethanil, 0.03 kg of N-phenylpyridin-4-amine, 0.02 kg of N-(2-methyl-5-nitrophenyl)-4-(3-pyridyl)-2-pyrimidinamine, and 0.02 kg of 2-(3-pyridyl)-4-pyrimidinamine, and stir for 40 min to obtain intermediate product B;

[0138] S3. Under stirring at 50 °C and a speed of 300 rpm, add intermediate product A to intermediate product B, continue stirring for 50 min, and then cool to room temperature to obtain the bactericidal defoamer for foam drainage.

[0139] In addition, the preparation method of the alkynediol polyether modified silicone oil in the formula is as follows:

[0140] S11. By mass, add 2.5 parts of tetramethyl decynediol, 2 parts of 1,4-pentadiyn-3-ol, and 0.09 part of sodium ethoxide to the reaction kettle, and purge with nitrogen for 40 min;

[0141] S12. Add 10 parts of 1,2-epoxybutane and 10 parts of 1,2-epoxypentane to the reaction kettle, continue purging with nitrogen until the pressure in the reaction kettle is 0.88 MPa, and at the same time heat the reaction system to 90 °C and carry out ring-opening polymerization reaction for 1.5 h;

[0142] S13. Cool the reaction system to room temperature and reduce the pressure in the reaction kettle to atmospheric pressure;

[0143] S14. Add 14 parts of phenylhydrogen silicone oil, 14 parts of ethylhydrogen silicone oil, and 0.0013 part of rhodium diacetate to the reaction kettle, heat to 96 °C, and carry out alkynyl addition reaction for 3 h;

[0144] S15. Cool the reaction system to room temperature and stop stirring to obtain the alkynediol polyether modified silicone oil.

[0145] The preparation method of the modified nano-silica in the formula is as follows:

[0146] S21. Weigh 7.5 parts of nano-silica with a specific surface area of 300 m² / g by mass and add it to a mixed solution composed of 50 parts of toluene and 50 parts of ethylene glycol. Stir at a speed of 400 rpm for 18 min to make it fully and evenly mixed.

[0147] S22. Place the liquid obtained in step S21 under ultrasonic waves for ultrasonic dispersion for 20 min. The ultrasonic frequency is 200 KHz to obtain a nano-silica dispersion.

[0148] S23. Place the nano-silica dispersion in a reaction kettle. Under the stirring condition of 400 rpm, add 0.3 parts of N-(β-aminoethyl)-γ-aminopropylmethyldimethoxysilane and 0.3 parts of 3-aminopropyltriethoxysilane to the reaction kettle. Heat the reaction system to 85 °C and react for 6 h. Then stop stirring and cool to room temperature to obtain a modified nano-silica mixture containing impurities.

[0149] S24. Centrifuge the modified nano-silica mixture containing impurities at a centrifugal speed of 16,000 rpm, remove the upper liquid to obtain the lower precipitate.

[0150] S25. Wash the lower precipitate with absolute ethanol 3 times, dry and grind it to obtain white and fluffy modified nano-silica.

[0151] Comparative Example 1:

[0152] Prepare a bactericidal defoamer for foam drainage according to the method, raw materials and dosages of Example 1, except that the alkynediol polyether modified silicone oil is replaced with methyl silicone oil commonly used in the prior art to obtain the product.

[0153] That is, the bactericidal defoamer for foam drainage in Comparative Example 1 includes the following components by mass percentage: 25% of methyl silicone oil, 10% of polyoxyethylene polyoxypropylene pentaerythritol ether with an average relative molecular mass of 3000 g / mol, 2% of modified nano-silica, 2% of polyoxyethyl polyoxypropyl glycerol ether, 1% of ethylene glycol monon-propyl ether, 0.5% of dodecyl dimethyl benzyl ammonium chloride, 0.01% of pyrimethanil, and the balance is water.

[0154] Comparative Example 2:

[0155] Prepare a bactericidal defoamer for foam drainage according to the method, raw materials and dosages of Example 2, except that polyoxyethylene polyoxypropylene pentaerythritol ether is not used. Obtain the product.

[0156] That is, the bactericidal defoamer for foam drainage in Comparative Example 2 comprises components in the following mass percentages: 30% of alkynediol polyether modified silicone oil, 3% of modified nano-silica, 3.5% of polyoxyethylated glycerol ether, 1.5% of ethylene glycol monomethyl ether, 1.25% of dodecyldimethylbenzylammonium bromide, 0.05% of N-phenylpyridin-4-amine, and the balance being water.

[0157] Comparative Example 3:

[0158] Except for not using or including ethylene glycol monoethyl ether, the bactericidal defoamer for foam drainage was prepared according to the method, raw materials and dosages of Example 3 to obtain the product.

[0159] That is, the bactericidal defoamer for foam drainage in Comparative Example 3 comprises components in the following mass percentages: 35% of alkynediol polyether modified silicone oil, 15% of polyoxyethylene polyoxypropylene pentaerythritol ether with an average relative molecular mass of 8000 g / mol, 4% of modified nano-silica, 5% of polyoxypropyl glycerol ether, 2% of octadecyldimethylbenzylammonium chloride, 0.1% of N-(2-methyl-5-nitrophenyl)-4-(3-pyridyl)-2-pyrimidinamine, and the balance being water.

[0160] Comparative Example 4:

[0161] The bactericidal defoamer for foam drainage was prepared according to the method, raw materials and dosages of Example 4, except that octadecyldimethylbenzylammonium bromide was used to replace 2-(3-pyridyl)-4-pyrimidinamine to obtain the product.

[0162] That is, the bactericidal defoamer for foam drainage in Comparative Example 4 comprises components in the following mass percentages: 27% of alkynediol polyether modified silicone oil, 14% of polyoxyethylene polyoxypropylene pentaerythritol ether with an average relative molecular mass of 6000 g / mol, 2.5% of modified nano-silica, 2% of polyoxyethyl polyoxypropyl glycerol ether, 2% of polyoxyethylated glycerol ether, 1.5% of ethylene glycol monobutyl ether, 1.08% of octadecyldimethylbenzylammonium bromide, and the balance being water.

[0163] Comparative Example 5:

[0164] The bactericidal defoamer for foam drainage was prepared according to the method, raw materials and dosages of Example 5, except that alkynediol polyether modified silicone oil was used to replace polyoxyethylene polyoxypropylene pentaerythritol ether to obtain the product.

[0165] That is, the bactericidal defoamer for foam drainage in Comparative Example 5 comprises components in the following mass percentages: 43% of alkynediol polyether modified silicone oil, 3.5% of modified nano-silica, 1% of polyoxyethyl polyoxypropyl glycerol ether, 1% of polyoxyethyl glycerol ether, 1% of polyoxypropyl glycerol ether, 1.8% of diethylene glycol butyl ether, 1.2% of benzyltriethylammonium chloride, 0.05% of pyrimethanil, 0.05% of N-phenylpyridin-4-amine, and the balance being water.

[0166] Comparative Example 6:

[0167] A bactericidal defoamer for foam drainage was prepared according to the method, raw materials and dosages of Example 6, except that the alkynediol polyether modified silicone oil and polyoxyethylene polyoxypropylene pentaerythritol ether commonly used in the prior art were replaced with methyl silicone oil, and the product was obtained.

[0168] That is, the bactericidal defoamer for foam drainage in Comparative Example 6 comprises components in the following mass percentages: 41% of methyl silicone oil, 2.5% of modified nano-silica, 1% of polyoxyethyl polyoxypropyl glycerol ether, 1.5% of polyoxyethyl glycerol ether, 1.5% of polyoxypropyl glycerol ether, 0.5% of ethylene glycol monon-propyl ether, 0.5% of ethylene glycol monomethyl ether, 0.5% of ethylene glycol monobutyl ether, 0.5% of diethylene glycol butyl ether, 0.5% of dodecyl dimethyl benzyl ammonium chloride, 0.5% of octadecyl dimethyl benzyl ammonium bromide, 1% of benzyltriethyl ammonium bromide, 0.03% of pyrimethanil, 0.03% of N-phenylpyridin-4-amine, 0.02% of N-(2-methyl-5-nitrophenyl)-4-(3-pyridyl)-2-pyrimidinamine, 0.02% of 2-(3-pyridyl)-4-pyrimidinamine, and the balance being water.

[0169] Next, performance tests will be conducted on the bactericidal corrosion inhibitor and scale inhibitor and foaming agent for foam drainage obtained in Examples 1-6 and Comparative Examples 1-6.

[0170] Test Index 1: Defoaming effect

[0171] Referring to the method specified in NB / T 11045.3—2023, 5 g of cocamidopropyl betaine was weighed and placed in mineralized water to prepare 1000 mL of foam liquid, and the defoaming effect test was carried out by simulating the foam liquid at the production site. The water quality of the mineralized water, by mass percentage, includes 4% of sodium chloride, 1% of calcium chloride, and 95% of deionized water.

[0172] Take 100 mL of the prepared foam liquid, stir it at a speed of 11000±300 rpm for 1 min for foaming, and then immediately pour it into a 500 mL graduated cylinder. At the same time, use a stopwatch to time and record the initial volume and the volume after standing for 3 min. Repeat the operation more than 3 times and record the data, and take the average value to obtain the initial foam volume V of the undefoamed agent. 00and the foam volume V after 3 min 03 .

[0173] Another 100 mL of the prepared foam liquid was taken, foamed by stirring at a speed of (11000 ± 300) rpm for 1 min, then 0.5 g of defoamer was added and stirred for another 1 min for defoaming, and then immediately poured into a 500 mL graduated cylinder. At the same time, a stopwatch was used to time, and the initial volume and the volume after standing for 3 min were recorded. The above operation was repeated more than 3 times and the data were recorded, and the average value was taken to obtain the initial foam volume V after adding the defoamer 10 and the upper layer foam volume V after 3 min 13 .

[0174] The initial defoaming rate was calculated according to the following formula:

[0175] D0 = (V 00 - V 10 ) / (V 00 - 100) × 100%;

[0176] In the formula:

[0177] D0 —— the initial defoaming rate, expressed as a percentage (%);

[0178] V 00 —— the initial foam volume without adding defoamer, in milliliters (mL);

[0179] V 10 —— the initial foam volume after adding defoamer, in milliliters (mL).

[0180] The 3 - min defoaming rate was calculated according to the following formula:

[0181] D1 = (V 03 - 100 - V 13 ) / (V 03 - 100) × 100%;

[0182] In the formula:

[0183] D1 —— the 3 - min defoaming rate, expressed as a percentage (%);

[0184] V 03 —— the foam volume after 3 min without adding defoamer, in milliliters (mL);

[0185] V 13 —— the foam volume after 3 min after adding defoamer, in milliliters (mL).

[0186] In the above two formulas, according to the regulations of the industry standard, V 00 , V 03 , V 10The foam volume shown actually includes the 100 ml of liquid itself; only by subtracting 100 can the actual volume of the foam itself be obtained. And V 13 is the upper-layer foam volume 3 minutes after adding the defoamer (i.e., the actual volume of the foam itself), excluding the 100 mL of liquid at the bottom.

[0187] The defoaming effect is shown in the following table:

[0188]

[0189] From the data comparison between the examples and comparative examples in the above table, it can be seen that the defoamers provided in Examples 1-6 of this application have an initial defoaming rate of over 99.5%, and the foam elimination rate after 3 minutes is 100%, showing excellent performance. In contrast, in the comparative examples, whether it is the initial defoaming rate or the 3-minute defoaming rate, the defoaming effect is not as good as that of Examples 1-6, which proves the unique defoamer formula of this application, with the components synergistically acting to achieve excellent defoaming effects.

[0190] Especially, the data gaps between Example 2 and Comparative Example 2, and between Example 6 and Comparative Example 6 are very large, which proves that polyoxyethylene polyoxypropylene pentaerythritol ether and alkynediol polyether modified silicone oil have synergistic effects and play an important defoaming role in this application.

[0191] Test Index 2: Bactericidal Rate

[0192] According to the method specified in SY / Y 0532-2012, take the water sample containing bacteria at the production site and prepare it into a foam liquid. Then test the bacterial content before and after adding the defoamer provided in this application, and further evaluate its bactericidal effect. To ensure the accuracy of the experiment, select the same water sample and conduct preliminary tests to ensure that the bacterial species and colony content of the water samples used in the comparative experiments are the same.

[0193] The bactericidal rate is calculated by the following formula:

[0194] Bactericidal rate = (bacterial content of the foaming liquid prepared from the water sample containing bacteria at the site before adding the defoamer - bacterial content of the foaming liquid prepared from the water sample containing bacteria at the site after adding the defoamer) / bacterial content of the foaming liquid prepared from the water sample containing bacteria at the site before adding the defoamer × 100%.

[0195] The bactericidal effect is shown in the following table:

[0196]

[0197] The above data prove that the defoamer provided in the examples of this application has excellent bactericidal effects, and the killing rates of sulfate-reducing bacteria, iron bacteria, and saprophytic bacteria reach 100%. Especially, the data of Comparative Example 4 are relatively low, and the comparison proves that the 2-(3-pyridyl)-4-pyrimidinamine component selected in this application has played a very prominent bactericidal effect.

[0198] Test Index 3: Dilution Stability

[0199] Weigh 40 g of the defoamer into a 250 mL beaker according to the method specified in NB / T 11045.3—2023. Measure 160 mL of distilled water with a measuring cylinder and add it to the beaker. Stir with a constant-speed electric stirrer at 300 rpm for 5 min, and then seal it and leave it to stand at room temperature for 24 h. Observe the stability of the defoamer after dilution with the naked eye under non-direct natural light.

[0200] The test results of dilution stability are shown in the following table:

[0201] Defoamer Test Purpose Test Results Example 1 Dilution Stability The diluted solution is a homogeneous liquid after 24h, without stratification, floating oil, precipitation or floccules Example 2 Dilution Stability The diluted solution is a homogeneous liquid after 24h, without stratification, floating oil, precipitation or floccules Example 3 Dilution Stability The diluted solution is a homogeneous liquid after 24h, without stratification, floating oil, precipitation or floccules Example 4 Dilution Stability The diluted solution is a homogeneous liquid after 24h, without stratification, floating oil, precipitation or floccules Example 5 Dilution Stability The diluted solution is a homogeneous liquid after 24h, without stratification, floating oil, precipitation or floccules Example 6 Dilution Stability The diluted solution is a homogeneous liquid after 24h, without stratification, floating oil, precipitation or floccules

[0202] It shows that for the bactericidal defoamer for foam drainage provided by the embodiments of the present application, after dilution and standing for 24 hours, the liquid still shows a uniform state, without stratification, floating oil, precipitation, or floccules, and the defoamer is still evenly dispersed in the liquid, with excellent stability.

[0203] The above are only the preferred embodiments of the present application and are not used to limit the present application. For those skilled in the art, various changes and modifications can be made to the present application. Any modification, equivalent replacement, improvement, etc. made within the spirit and principle of the present application shall be included within the protection scope of the present application.

Claims

1. A bactericidal defoamer for foam drainage, characterized in that, It comprises components in the following mass percentages: 25-35% of alkynediol polyether modified silicone oil, 10-15% of polyoxyethylene polyoxypropylene pentaerythritol ether, 2-4% of modified nano-silica, 2-5% of emulsifier, 1-2% of cosolvent, 0.5-2% of benzyl quaternary ammonium salt disinfectant, 0.01-0.1% of pyrimidine amine fungicide, and the balance is water; Among them, the preparation method of the alkynediol polyether modified silicone oil is as follows: Step S1: By mass, add 3-5 parts of alkynediol and 0.05-0.15 parts of alcohol base into the reaction kettle and stir, and introduce inert gas to displace for 30-60 min; Step S2: Add 18-26 parts of liquid epoxy alkane, continue to introduce inert gas to make the pressure in the reaction kettle 0.8-1.0 MPa, heat the reaction system to 85-95 °C, and react for 1-2 h; Step S3: Cool the reaction system to room temperature, and reduce the pressure in the reaction kettle to atmospheric pressure; Step S4: Add 25-35 parts of hydrogen-containing silicone oil and 0.001-0.002 parts of catalyst into the reaction kettle, heat to 90-100 °C, and react for 2-4 h; the catalyst is at least one of bis[(α,α,α′,α′-tetramethyl-1,3-benzenedipropanoic acid) rhodium] and rhodium diacetate; Step S5: Cool the reaction system to room temperature.

2. The bactericidal defoamer for foam drainage according to claim 1, characterized in that, The benzyl quaternary ammonium salt disinfectant is one or more of dodecyldimethylbenzylammonium chloride, dodecyldimethylbenzylammonium bromide, octadecyldimethylbenzylammonium chloride, octadecyldimethylbenzylammonium bromide, benzyltriethylammonium chloride, and benzyltriethylammonium bromide.

3. The bactericidal defoaming agent for foam drainage according to claim 1, characterized in that, The pyrimidine amine fungicide is one or more of pyrimethanil, N-phenylpyridin-4-amine, N-(2-methyl-5-nitrophenyl)-4-(3-pyridyl)-2-pyrimidinamine, and 2-(3-pyridyl)-4-pyrimidinamine.

4. The bactericidal defoamer for foam drainage according to claim 1, characterized in that, The alkynediol in Step S1 is one or more of 1,4-butynediol, dimethyloctynediol, tetramethyldecynediol, and 1,4-pentadiyn-3-ol.

5. The bactericidal defoamer for foam drainage according to claim 1, wherein The liquid epoxy alkane in Step S2 is one or more of propylene oxide, 1,2-epoxybutane, and 1,2-epoxypentane.

6. The bactericidal defoaming agent for foam drainage according to claim 1, wherein The preparation method of the modified nano-silica is as follows: Step S1: By mass, take 5-8 parts of nano-silica and add it to 80-120 parts of dispersant, and stir evenly; Step S2: Perform ultrasonic dispersion to obtain a nano-silica dispersion; Step S3: Place the nano-silica dispersion in a reaction kettle, add 0.5-0.8 parts of coupling agent, heat to 75-95 °C and react for 5-7 h, then stop stirring and cool to room temperature to obtain a modified nano-silica mixture containing impurities; Step S4: Centrifuge the modified nano-silica mixture containing impurities to remove the upper layer liquid and obtain the lower layer precipitate; Step S5: Wash, dry, and grind the lower layer precipitate to obtain modified nano-silica.

7. The bactericidal defoamer for foam drainage according to claim 6, wherein The coupling agent in Step S3 is one or more of N-(β-aminoethyl)-γ-aminopropylmethyldimethoxysilane, 3-aminopropyltriethoxysilane, and N-(β-aminoethyl)-γ-aminopropyltrimethoxysilane.

8. A preparation method of the bactericidal defoamer for foam drainage as described in claim 1, characterized in that, It includes the following steps: Step S1: Add alkynediol polyether modified silicone oil into the reaction kettle, heat it to 70 - 90°C and stir at a speed of 300 - 600 rpm; then slowly add modified nano-silica and continue to stir for 70 - 90 min; then cool it down to below 60°C, and then add polyoxyethylene polyoxypropylene pentaerythritol ether and continue to stir for 30 - 60 min to obtain intermediate product A; Step S2: Add water into another reaction kettle, heat it to 40 - 60°C and keep stirring at a speed of 200 - 400 rpm, then add emulsifier, co-solvent, benzyl quaternary ammonium salt disinfectant, and pyrimidine amine fungicide, and stir for 30 - 60 min to obtain intermediate product B; Step S3: Under the condition of stirring at 40 - 60°C and a speed of 200 - 400 rpm, add intermediate product A into intermediate product B and continue to stir for 30 - 60 min.

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