Preparation method and application of reinforced boric acid efficient environment-friendly phosphorus-free scale and corrosion inhibitor

Abstract

The invention relates to the technical field of scale and corrosion inhibitors, in particular to a preparation method and application of an enhanced boric acid efficient environment-friendly phosphorus-free scale and corrosion inhibitor, and the enhanced boric acid efficient environment-friendly phosphorus-free scale and corrosion inhibitor comprises the following components in parts by weight: 50-100 parts of a water-soluble polyol-boric acid mixture, 0-50 parts of polyepoxysuccinic acid, 0-50 parts of polyaspartic acid, 0-50 parts of benzotriazole and 0-50 parts of zinc chloride. The high intermiscibility of polyhydric alcohol, water and boric acid is utilized, the dosage of boric acid in a solution is effectively increased, the effects of boric acid on scale inhibition, corrosion inhibition, sterilization and the like are amplified, meanwhile, the freezing temperature of the scale and corrosion inhibitor is reduced due to the addition of polyhydric alcohol, the scale and corrosion inhibitor can be used in winter more easily, and the scale and corrosion inhibitor is suitable for popularization and application. The invention provides an implementation way of a novel efficient environment-friendly phosphorus-free scale and corrosion inhibitor, and the scale and corrosion inhibitor has the advantages of environment friendliness, convenience in use and good scale and corrosion inhibition performance.

Description

Technical Field

[0001] The invention relates to the technical field of scale and corrosion inhibitors, and in particular to a preparation method and application of a reinforced boric acid-based high-efficiency, environmentally friendly, phosphorus-free scale and corrosion inhibitor. Background Art

[0002] Cooling water accounts for 60-80% of the total water consumption in industrial water. Therefore, the main goal of saving industrial water is to recycle cooling water, maximize the reuse rate, and reduce sewage discharge. As the composition of water used in industrial systems becomes more and more complex, this will lead to three major problems: scaling, corrosion, and microbial slime.

[0003] In circulating cooling water, the concentration of some salt substances increases with the evaporation of water. When the concentration reaches a supersaturated state, these substances will crystallize and adsorb on the surface of the equipment to form scale, such as calcium carbonate, calcium sulfate, etc. The adsorption of scale on the surface of the equipment will cause the inner diameter of the equipment to become smaller, the flow rate of the fluid will be limited, and the working efficiency will be reduced. The long-term adsorption of scale will cause corrosion of the equipment. The corrosion process is mainly the chemical and electrochemical reaction of the medium environment to the metal material. If it is in a corrosive environment for a long time, the surface of the equipment is prone to perforation, making the equipment unsafe. There is a certain correlation between scaling and corrosion. The scale generated in the environment adsorbed on the surface of the equipment will cause under-scale corrosion. At the same time, the corrosion product (such as Fe2O3) is also a form of scale.

[0004] In order to solve the hazards caused by scaling and corrosion, adding scale inhibitors is a convenient and effective method. The mechanism of action of scale inhibitors is mainly to slow down the crystallization process of scaling salts, including chelation solubilization, threshold effect, lattice distortion, dispersion, etc. Scale inhibitors are usually composed of polar groups and non-polar groups. Through electron transfer, scale inhibitors will form metal complexes with the metal surface in the form of coordination bonds. Traditional scale inhibitors include organic phosphonic acids and multi-polymers such as HEDP, PBTC, and PAA, and new green scale inhibitors include environmentally friendly copolymers such as PESA and PASP. Since the active ingredients all use water as a solvent, the agent has the disadvantage of being easy to freeze in winter, which is particularly serious in the north.

[0005] Boric acid is a colorless and transparent crystal. When added to water, it has multiple functions such as scale inhibition, corrosion inhibition, and sterilization. Boric acid will produce a complex ion system in water, which can reduce the content of calcium and magnesium ions in water, thereby reducing the formation of scale. Boric acid can also form a protective film inside the metal pipe, effectively improving the antioxidant and corrosion resistance of the metal pipe. At the same time, boric acid itself is a harmless substance, not only harmless to the human body. It can also play a certain bactericidal role and improve the effect of bactericidal algaecides in circulating cooling water.

[0006] However, boric acid is a monobasic extremely weak acid with weak acidity. When the amount added is small, the scale and corrosion inhibitor effect is weak. Although boric acid can be dissolved in water, its solubility is low. At room temperature, the solubility of boric acid is about 4.3g / 100mL, which means that adding too much boric acid to water will cause it to be unable to dissolve completely. Therefore, boric acid is rarely used in scale and corrosion inhibitors. Even if it is used, the amount added is very small, and it is difficult to bring out the performance advantages of boric acid. Summary of the invention

[0007] The purpose of the present invention is to provide a preparation method and application of an enhanced boric acid-based high-efficiency, environmentally friendly, phosphorus-free scale and corrosion inhibitor, by taking boric acid as one of the main active ingredients of the scale and corrosion inhibitor, and finding another new dissolving medium, the solubility of boric acid is improved, the scale inhibition, corrosion inhibition and sterilization effects of boric acid are amplified, and the freezing temperature of the agent is reduced, thereby comprehensively improving the performance of the compounded scale and corrosion inhibitor, while ensuring environmental protection properties and reducing production and use costs.

[0008] The above technical objectives of the present invention are achieved through the following technical solutions:

[0009] The present invention provides a reinforced boric acid-based high-efficiency, environmentally friendly, phosphorus-free scale and corrosion inhibitor, which comprises the following components in parts by weight:

[0010] 50-100 parts of water-soluble polyol-boric acid mixture, 0-50 parts of polyepoxysuccinic acid, 0-50 parts of polyaspartic acid, 0-50 parts of benzotriazole and 0-50 parts of zinc chloride.

[0011] Furthermore, in the water-soluble polyol-boric acid mixture, the ratio of the water-soluble polyol to the boric acid is 1-3.

[0012] Furthermore, the water-soluble polyol is any one of sorbitol, xylitol or glycerol, or a mixture of several of them.

[0013] Furthermore, the preparation method of the water-soluble polyol-boric acid mixture is as follows:

[0014] Mixing water-soluble polyol and boric acid at 40-60°C;

[0015] Under stirring conditions, add an alkaline buffer to adjust the pH to 5.5-7.0;

[0016] Use ultrasonic dispersion or high shear stirring;

[0017] The mixture was cooled to room temperature and the insoluble matter was removed by filtration to obtain a solution of a polyol-boric acid mixture.

[0018] Further, a 30% solution of polyepoxysuccinic acid and a 30% solution of polyaspartic acid are prepared in advance, and the pH values ​​thereof are adjusted to 7.0 to 8.5;

[0019] Polyepoxysuccinic acid and polyaspartic acid were added in stages with slow stirring.

[0020] The pH value of the entire system is controlled to be maintained at 6.5-7.5 to ensure the activity of the scale inhibitor.

[0021] Furthermore, spray drying or phase separation method is used to coat benzotriazole with polyvinyl pyrrolidone or gelatin-arabic gum system to form pH-responsive microcapsules.

[0022] Furthermore, pH-sensitive polymer is used to load zinc chloride.

[0023] Furthermore, the pH sensitive polymer is polyacrylic acid or chitosan-alginate composite material.

[0024] The present invention provides a method for preparing a reinforced boric acid-based high-efficiency, environmentally friendly, phosphorus-free scale and corrosion inhibitor, comprising the following steps:

[0025] Mixing a water-soluble polyol with boric acid at 40 to 60° C. to obtain a polyol-boric acid mixture solution;

[0026] Adding 30% polyepoxysuccinic acid solution and 30% polyaspartic acid solution into the polyol-boric acid mixture solution, stirring evenly to obtain a scale inhibitor solution;

[0027] Under stirring conditions, the prepared pH-responsive microcapsules and pH-sensitive polymer-loaded zinc chloride are slowly added to the scale inhibitor solution and stirred continuously.

[0028] The present invention also provides an application of a reinforced boric acid-based high-efficiency, environmentally friendly, phosphorus-free scale and corrosion inhibitor, and the corrosion inhibitor is used in circulating cooling water.

[0029] In summary, the present invention has the following beneficial effects:

[0030] The present invention utilizes the high compatibility of polyols with water and boric acid, effectively increases the amount of boric acid in the solution, and amplifies the effects of boric acid in scale inhibition, corrosion inhibition, sterilization and the like. At the same time, the addition of polyols reduces the freezing temperature of the scale inhibitor and corrosion inhibitor, which is more conducive to its use in winter. The present invention provides a new method for realizing a highly efficient and environmentally friendly phosphorus-free scale inhibitor and corrosion inhibitor, and has the advantages of being environmentally friendly, easy to use, and having good scale inhibition and corrosion inhibition performance. DETAILED DESCRIPTION

[0031] In order to further explain the technical means and effects adopted by the present invention to achieve the predetermined purpose of the invention, the preparation method and application of a reinforced boric acid-based high-efficiency, environmentally friendly, phosphorus-free scale and corrosion inhibitor proposed by the present invention, its specific implementation method, characteristics and effects are described in detail as follows.

[0032] The present specific embodiment provides a reinforced boric acid-based high-efficiency, environmentally friendly, phosphorus-free scale and corrosion inhibitor, which comprises the following components in parts by weight:

[0033] 50-100 parts of water-soluble polyol-boric acid mixture, 0-50 parts of polyepoxysuccinic acid, 0-50 parts of polyaspartic acid, 0-50 parts of benzotriazole and 0-50 parts of zinc chloride.

[0034] It is understandable that most common industrial circulating water scale inhibitors are mainly organic phosphonic acid or multi-polymers, which will cause great pollution to the environment during production and use, especially organic phosphonic acid, whose high phosphorus content puts great pressure on the environment. Therefore, new raw materials with scale and corrosion inhibition effects are sought to replace traditional components to a certain extent, so as to obtain low-phosphorus or even phosphorus-free scale and corrosion inhibitor formulas, which will reduce the pressure on the environment without affecting the scale and corrosion inhibition effect. Boric acid has the above advantages, but due to its low water solubility, it has not been widely used and can only be added in small amounts to replace the effective ingredients.

[0035] Boric acid, as a scale and corrosion inhibitor component for industrial circulating cooling water, has three major effects: scale inhibition, corrosion inhibition, and sterilization. Boric acid itself is an acidic substance. Adding boric acid to water will produce a complex ion system, which can reduce the content of calcium and magnesium ions in the water, thereby reducing the formation of scale. The equipment and pipelines of circulating cooling water are made of metal materials. If exposed to air and water, chemical reactions will occur and corrode. Boric acid can form a protective film with the metal in the pipeline, slowing down the oxidation and corrosion process of the metal; Boric acid can play a role in sterilization in water, which can improve the effect of bactericidal algaecides in circulating cooling water. At the same time, boric acid itself is a harmless substance, harmless to the human body and the environment.

[0036] Boric acid is a monobasic extremely weak acid. The source of its acidity is not that it gives protons by itself. Since boron is an electron-deficient atom, it can add the hydroxide ions of water molecules and release protons. By utilizing this electron-deficient property, after adding polyols, the polyhydroxyl groups of the polyols can undergo an esterification reaction with boric acid to generate a stable complex, reduce the concentration of borate ions, and promote the ionization of boric acid, thereby enhancing the solubility of boric acid and further enhancing the acidity of the solution, thereby strengthening the performance of boric acid. The more hydroxyl groups of the polyols, the stronger the enhancement effect on the solubility and effect of boric acid. The polyols that can be used include, but are not limited to, sorbitol, xylitol, glycerol, etc.

[0037] This specific embodiment also discloses the synergistic effect of the compounding of boric acid with polyepoxysuccinic acid, and / or polyaspartic acid, and / or benzotriazole, and / or zinc chloride. Boric acid, as the main component of the scale inhibitor and corrosion inhibitor, has the effects of scale inhibition, corrosion inhibition, and sterilization. It can synergize with polyepoxysuccinic acid and polyaspartic acid to inhibit scale, synergize with benzotriazole and zinc chloride to inhibit corrosion, and synergize with the bactericide and algaecide added to the circulating cooling water to kill bacteria, which greatly enhances the use effect of the scale inhibitor and corrosion inhibitor.

[0038] The environmentally friendly phosphorus-free scale and corrosion inhibitor provided by this specific embodiment avoids the use of phosphorus-containing compounds, has the characteristics of being phosphorus-free, meets the requirements of green environmental protection, reduces the environmental burden, and can effectively reduce the bacterial corrosion and algae growth problems of the circulating water system, thereby reducing the amount of bactericidal algaecides used in the circulating water, reducing the secondary pollution problems caused by the use of bactericidal algaecides, and significantly reducing the treatment costs and daily maintenance workload of cooling water; the scale and corrosion inhibitor of the present invention has a high tolerance to calcium and alkali, is resistant to corrosion by high concentrations of chloride ions and sulfate ions, and has a wide range of adaptability to water quality, providing technical conditions for the operation of circulating water at high concentration multiples and reducing sewage discharge; the scale and corrosion inhibitor of the present invention has excellent scale and corrosion inhibition performance in the application of circulating water systems, with a small amount of addition, a simple scale treatment process and obvious effects, and is easy to promote and apply. The use of polyols also reduces the freezing temperature of scale and corrosion inhibitors, which is more conducive to their use in winter.

[0039] In some preferred embodiments, in the water-soluble polyol-boric acid mixture, the ratio of the water-soluble polyol to the boric acid is 1-3.

[0040] In some preferred embodiments, the water-soluble polyol is any one of sorbitol, xylitol or glycerol or a mixture of several of them.

[0041] In some preferred embodiments, the preparation method of the water-soluble polyol-boric acid mixture is as follows:

[0042] Mixing water-soluble polyol and boric acid at 40-60°C;

[0043] Under stirring conditions, add an alkaline buffer to adjust the pH to 5.5-7.0;

[0044] Use ultrasonic dispersion or high shear stirring;

[0045] The mixture was cooled to room temperature and the insoluble matter was removed by filtration to obtain a solution of a polyol-boric acid mixture.

[0046] It can be understood that in the corrosion inhibitor provided in this specific embodiment, the preparation process of the water-soluble polyol-boric acid mixture involves complex reaction, pH control, dispersion homogenization and stability optimization, which is mainly based on complex reaction (Chelation Reaction). Polyols (such as sorbitol, xylitol or glycerol) contain multiple hydroxyl groups (-OH) and can form a stable coordination complex with boric acid (H3BO3).

[0047] The complexation reaction is as follows:

[0048]

[0049] This complex can improve the water solubility of boric acid and prevent its self-polymerization (such as forming insoluble metaboric acid).

[0050] Boric acid itself is a weak acid and is easily affected by pH. In the pH range of 5.5 to 7.0, boric acid mainly exists in the form of a single molecule and can form a stable complex with polyols; alkaline buffers (such as sodium citrate or sodium bicarbonate) prevent boric acid precipitation (avoid the formation of H2BO3 - or polyboric acid), thereby maintaining the stability of the complex reaction and avoiding dissociation of the complex caused by extreme pH.

[0051] Among them, ultrasonic dispersion or high shear stirring, ultrasonic dispersion (20-40kHz), ultrasonic waves generate microbubbles, forming a high-energy cavitation effect in the solution, allowing boric acid and polyols to fully contact and promote complexation reactions; high shear stirring (>500rpm) forms a micron / nano-scale dispersion system to ensure the uniformity of the solution and improve the stability of the mixture.

[0052] The complex forms faster at higher temperatures (40-60°C), but is more stable at room temperature (25°C). Filtration can remove undissolved boric acid or reaction by-products and improve the transparency and uniformity of the solution.

[0053] In general, the solubility of pure boric acid in water is low (about 4.7g / 100mL, 25°C), but after complexing with polyols, the water solubility is significantly improved, reaching several times the solubility, which ensures the uniform distribution of the formula in the water treatment system. The complexed boric acid-polyol complex can form a dynamic complex network, which can effectively capture calcium and magnesium ions in water and reduce the risk of scale deposition; and by stabilizing the pH, it can prevent the metal surface in the water from being corroded by local acid. The complex can also form a protective film on the metal surface to reduce the corrosion rate.

[0054] Through complexation and dispersion technology, boric acid precipitation is prevented, the long-term storage stability of scale and corrosion inhibitors is improved, pH is maintained at 5.5-7.0, and component degradation or deposition caused by extreme pH is avoided. Traditional scale inhibitors (such as HEDP) contain phosphorus, which can easily cause eutrophication of water bodies, while boric acid-polyol complexes are an environmentally friendly alternative without the risk of phosphorus pollution.

[0055] In some preferred embodiments, a 30% solution of polyepoxysuccinic acid and a 30% solution of polyaspartic acid are pre-prepared, and the pH values ​​thereof are adjusted to 7.0 to 8.5;

[0056] Add polyepoxysuccinic acid and polyaspartic acid in stages under slow stirring;

[0057] The pH value of the entire system was controlled to be maintained between 6.5 and 7.5.

[0058] It can be understood that the core of this step is to optimize the solubility, dispersibility and scale inhibition performance of PESA and PASP to ensure their stability and synergistic effect in the final formulation.

[0059] PESA (polyepoxysuccinic acid) and PASP (polyaspartic acid) are both phosphorus-free and environmentally friendly scale inhibitors, but they behave differently in different pH environments: PESA is stable in weak alkalinity (pH7.0-8.5), and the unfolding of the molecular chain is more conducive to the complexation of calcium and magnesium ions. PASP has the best chelating ability at pH7.0-8.5, and can more effectively inhibit the precipitation of scaling salts such as calcium carbonate and calcium sulfate. By adjusting the pH to 7.0-8.5, the stability of the solution is guaranteed and the molecular activity is improved.

[0060] PESA and PASP are both high molecular weight polymers with a certain viscosity in water. If added all at once, it may lead to excessive local concentration and form gel clumps, affecting dispersibility and activity. Adding them in stages can ensure that the two are evenly mixed to avoid precipitation or mutual influence on complexing ability.

[0061] Specifically, at a stirring rate of 200 to 400 rpm, add in batches according to a volume ratio of 3:2 (PESA:PASP); after each addition, wait for 10 to 15 minutes to ensure complete dissolution and uniform dispersion.

[0062] pH is too low (<6.5): PESA and PASP undergo molecular condensation, which reduces the scale inhibition effect and may increase corrosiveness, which is not conducive to metal corrosion inhibition performance.

[0063] Too high pH (>7.5): The solubility of PESA and PASP decreases, forming flocculent precipitation, affecting stability; too high pH value will cause certain metal ions (such as Fe 3+ ) forms insoluble precipitates, affecting the water treatment effect.

[0064] PESA: It has a high inhibition rate for calcium carbonate (CaCO3) and calcium sulfate (CaSO4) scaling, and can effectively prevent crystal growth; PASP: It also has excellent inhibition ability for special scales such as calcium phosphate (Ca3(PO4)2) and magnesium hydroxide (Mg(OH)2). PESA provides good dispersibility and PASP provides chelation. The combination of the two can increase the scale inhibition efficiency by 10-20%.

[0065] Adjust the pH in advance to avoid precipitation caused by pH fluctuations in subsequent formulas. Add in stages to ensure that PESA and PASP are completely dissolved, avoid gelation or agglomeration, and improve storage stability. It can more effectively prevent scaling in industrial circulating cooling water, boiler water, seawater desalination and other environments. It is suitable for water treatment systems with different pH ranges (6.5-8.5) to ensure wide applicability.

[0066] In some specific embodiments, spray drying or phase separation is used to coat benzotriazole with polyvinyl pyrrolidone or gelatin-arabic gum system to form pH-responsive microcapsules.

[0067] It is understandable that benzotriazole (BTA) is a common corrosion inhibitor that can effectively prevent the corrosion of copper and its alloys. However, BTA has problems such as easy solubility, excessive release, and short-term effectiveness in water treatment systems. Therefore, microencapsulation technology is used for coating to make it have pH-responsive slow-release characteristics, prolong the corrosion inhibition effect, and reduce environmental impact.

[0068] The mixed solution of BTA and coating material (polyvinyl pyrrolidone PVP or gelatin-arabic gum system) is sprayed into a hot air drying tower through an atomizing nozzle to quickly evaporate the water so that the BTA is coated to form microcapsules.

[0069] The specific steps are as follows: prepare 5-10% (w / v) BTA solution; select coating materials (PVP, gelatin-arabic gum) to prepare 10-15% (w / v) solution, adjust the pH to 6.5-7.5 to improve the coating efficiency; slowly add the BTA solution to the coating material solution and stir evenly; through the spray drying equipment, control the inlet temperature to 80-120°C, the outlet temperature to 40-60°C, and the air flow rate to 5-10m / s to form a uniform microcapsule powder.

[0070] Alternatively, by changing the polarity of the solvent or adding a non-solvent, the coating material (PVP or gelatin-arabic gum) is phase-separated in the solution to form a microcapsule shell that encapsulates BTA.

[0071] The specific steps are as follows:

[0072] BTA (5-10% w / v) is prepared in an aqueous solution; a gelatin-arabic gum composite system is used, and the pH is controlled at 6.5-7.5 to form a stable dispersion; the temperature is gradually lowered to 10-15° C., and a cross-linking agent (glutaraldehyde or sodium tripolyphosphate) is added to phase separate the gelatin-arabic gum and coat the BTA; the gelatin-arabic gum is filtered and dried to obtain pH-responsive microcapsules.

[0073] By using pH-sensitive materials (such as PVP or gelatin-arabic gum system), the release rate of BTA can be controlled according to the pH changes of the water treatment system. In a neutral or weakly acidic (pH 6.0-7.5) environment, the microcapsules remain closed and BTA is released slowly, reducing waste. In an alkaline (pH>7.5) environment, the microcapsule shell swells or degrades, and BTA is gradually released, improving the corrosion inhibition effect.

[0074] Traditional BTA dissolves quickly in water, while microencapsulation can achieve slow release, increase the corrosion inhibition time by 2 to 3 times, and reduce the frequency of addition. The use of pH-responsive microcapsules ensures that BTA releases more effectively under alkaline conditions and reduces release under neutral or acidic conditions, thereby improving the corrosion inhibition effect. Excessive BTA may affect water quality, and microencapsulation can accurately control the release amount, avoid excessive consumption, and improve utilization efficiency. BTA microcapsules can prevent photodegradation, oxidation, and chemical degradation, and are more stable in high-temperature and high-salinity water treatment. Traditional BTA and other components (such as Zn 2+ ) will produce adverse interactions, while microencapsulation can reduce direct contact between ingredients and improve formulation stability.

[0075] In some preferred embodiments, a pH sensitive polymer is used to support zinc chloride.

[0076] It is understood that zinc chloride (ZnCl2) is a corrosion inhibitor that can inhibit corrosion of metal surfaces in water treatment. 2+ It has high solubility in water. If it is added directly, it may lead to rapid release, short-term failure, and even the formation of Zn(OH)2 precipitation in a high pH environment. Therefore, pH-sensitive polymer loading technology can be used to achieve Zn 2+ It can slowly release, enhance the corrosion inhibition effect, and adapt to different water quality environments.

[0077] pH-sensitive polymers can change their structure (swell or degrade) within a specific pH range, controlling the Zn 2+ The pH sensitive materials selected in this embodiment include:

[0078] Polyacrylic acid (PAA): swells at pH>7.0 and promotes Zn 2+ Release; Chitosan-alginate complex: degrades under weak alkaline conditions and slowly releases Zn 2+ ; Poly N- Isopropyl acrylamide (PNIPAM): pH and temperature responsive, capable of controlling Zn 2+ release rate.

[0079] In this specific embodiment, the method for loading zinc chloride comprises:

[0080] (1) Using sol-gel technology, ZnCl2 is evenly dispersed in a pH-sensitive polymer network and cross-linked to form a solid gel that gradually releases Zn in water. 2+ .

[0081] The specific steps include:

[0082] Prepare 5-10% (w / v) pH sensitive polymer solution (such as PAA or chitosan-alginate); slowly add ZnCl2 solution (concentration 0.10.5M) under stirring (300-500rpm) to ensure that Zn 2+ Evenly distributed; using Ca 2+ or glutaraldehyde cross-linking to form gel particles, making Zn 2+ Fixed in the polymer network; filtered and dried to obtain pH-responsive Zn 2+ Slow-release granules.

[0083] (2) Layer-by-Layer (LbL) self-assembly method, ZnCl2 is embedded layer by layer into pH-sensitive polymers (such as PAA or chitosan-alginate complexes) through electrostatic interaction or hydrogen bonding to achieve Zn 2+ controlled release.

[0084] The specific steps include:

[0085] At pH 5.0-6.5, Zn was deposited alternately. 2+ solution and pH-sensitive polymer to form a nanoscale film; repeatedly deposit 5 to 10 layers to control Zn 2+ release rate; nanocomposite corrosion inhibition material was obtained by freeze drying.

[0086] At pH 6.5-7.5 (neutral), Zn 2+ Slow release ensures stable corrosion inhibition; under pH>8.0 (alkaline) conditions, pH-sensitive polymers swell or degrade, accelerating Zn 2+ Release, enhance corrosion inhibition performance; under pH <6.0 (acidic) conditions, Zn 2+ Release is reduced, excessive consumption is avoided, and the durability of water treatment agents is improved.

[0087] Traditional zinc chloride is released once, resulting in Zn 2+The pH-sensitive polymer can control the release rate and increase the corrosion inhibition time by 2 to 3 times. 2+ It is easy to form Zn(OH)2 precipitation, which affects the water quality. Use pH sensitive polymer to load Zn 2+ , reduce the risk of precipitation, improve solubility and ensure stable corrosion inhibition.

[0088] Traditional Zn 2+ The effect of corrosion inhibitors is unstable under different pH environments, while pH sensitive release technology can intelligently adjust Zn according to the pH changes of water quality. 2+ Release amount, suitable for more water treatment systems (such as cooling water, boiler water, seawater desalination, etc.). Excess Zn 2 + Discharge will cause water pollution, pH response technology can accurately control Zn 2+ Release, reduce dosage and reduce environmental risks.

[0089] Traditional ZnCl2 solution is easily hydrolyzed, while pH-sensitive polymer loaded Zn 2+ It can prevent its degradation, improve storage stability and extend the shelf life of the product.

[0090] In some preferred embodiments, the pH sensitive polymer is polyacrylic acid or a chitosan-alginate composite.

[0091] In some preferred embodiments, a method for preparing a reinforced boric acid-based high-efficiency, environmentally friendly, phosphorus-free scale and corrosion inhibitor comprises the following steps:

[0092] Mixing a water-soluble polyol with boric acid at 40 to 60° C. to obtain a polyol-boric acid mixture solution;

[0093] Adding 30% polyepoxysuccinic acid solution and 30% polyaspartic acid solution into the polyol-boric acid mixture solution, stirring evenly to obtain a scale inhibitor solution;

[0094] Under stirring conditions, the prepared pH-responsive microcapsules and pH-sensitive polymer-loaded zinc chloride are slowly added to the scale inhibitor solution and stirred continuously.

[0095] In some preferred embodiments, an enhanced boric acid-based high-efficiency, environmentally friendly, phosphorus-free scale and corrosion inhibitor is used in circulating cooling water.

[0096] The present invention will be further described below in conjunction with specific embodiments.

[0097] Example 1

[0098] This embodiment 1 provides a reinforced boric acid-based high-efficiency, environmentally friendly, phosphorus-free scale and corrosion inhibitor, which includes the following components in parts by weight:

[0099] Water-soluble polyol-boric acid mixture: 30 parts (sorbitol and boric acid are mixed in a ratio of 2:1); polyepoxysuccinic acid (PESA): 25 parts (30% solution); polyaspartic acid (PASP): 25 parts (30% solution); benzotriazole (BTA) microcapsules: 10 parts (PVP coating, spray drying method); zinc chloride (ZnCl2) pH-sensitive load: 10 parts (chitosan-alginate complex load).

[0100] This embodiment 1 provides a method for preparing a reinforced boric acid-based high-efficiency, environmentally friendly, phosphorus-free scale and corrosion inhibitor as follows:

[0101] S1. Prepare a water-soluble polyol-boric acid mixture. At 50° C., mix sorbitol and boric acid in a ratio of 2:1 and stir for 20 minutes. Add an alkaline buffer (sodium citrate) and adjust the pH to 6.0. Use ultrasonic dispersion (30kHz) for 15 minutes to promote complex formation. Cool to room temperature and filter to obtain a stable polyol-boric acid solution.

[0102] S2. Prepare the antiscalant solution, prepare 30% PESA solution (pH 7.5) and 30% PASP solution (pH 8.0); add PESA and PASP in stages under slow stirring (300 rpm), maintain the pH at 6.8-7.2, continue stirring for 30 minutes, and obtain a uniform antiscalant solution.

[0103] S3. Add corrosion inhibitor, and slowly add pH-responsive BTA microcapsules (PVP-coated) under stirring conditions; add pH-sensitive loaded zinc chloride (ZnCl2), and continue stirring for 30 minutes; filter and package to obtain the final scale and corrosion inhibitor product.

[0104] Example 2

[0105] This embodiment 2 provides a reinforced boric acid-based high-efficiency, environmentally friendly, phosphorus-free scale and corrosion inhibitor, which includes the following components in parts by weight:

[0106] Water-soluble polyol-boric acid mixture: 40 parts (sorbitol and boric acid in a ratio of 2:1); polyepoxysuccinic acid (PESA): 20 parts (30% solution); polyaspartic acid (PASP): 20 parts (30% solution); benzotriazole (BTA) microcapsules: 10 parts (PVP coating, spray drying method); zinc chloride (ZnCl2) pH sensitive load: 10 parts (chitosan-alginate complex load).

[0107] This embodiment 2 provides a method for preparing a reinforced boric acid-based high-efficiency, environmentally friendly, phosphorus-free scale and corrosion inhibitor as follows:

[0108] S1. Prepare a water-soluble polyol-boric acid mixture. At 50° C., mix sorbitol and boric acid in a ratio of 2:1 and stir for 20 minutes. Add an alkaline buffer (sodium citrate) and adjust the pH to 6.0. Use ultrasonic dispersion (30kHz) for 15 minutes to promote complex formation. Cool to room temperature and filter to obtain a stable polyol-boric acid solution.

[0109] S2. Prepare the antiscalant solution, prepare 30% PESA solution (pH 7.5) and 30% PASP solution (pH 8.0); add PESA and PASP in stages under slow stirring (300 rpm), maintain the pH at 6.8-7.2, continue stirring for 30 minutes, and obtain a uniform antiscalant solution.

[0110] S3. Add corrosion inhibitor, and slowly add pH-responsive BTA microcapsules (PVP-coated) under stirring conditions; add pH-sensitive loaded zinc chloride (ZnCl2), and continue stirring for 30 minutes; filter and package to obtain the final scale and corrosion inhibitor product.

[0111] Example 3

[0112] This embodiment 3 provides a reinforced boric acid-based high-efficiency, environmentally friendly, phosphorus-free scale and corrosion inhibitor, which includes the following components in parts by weight:

[0113] Water-soluble polyol-boric acid mixture: 50 parts (sorbitol and boric acid in a ratio of 2:1); polyepoxysuccinic acid (PESA): 15 parts (30% solution); polyaspartic acid (PASP): 15 parts (30% solution); benzotriazole (BTA) microcapsules: 10 parts (PVP coating, spray drying method); zinc chloride (ZnCl2) pH sensitive load: 10 parts (chitosan-alginate complex load).

[0114] This embodiment 3 provides a method for preparing a reinforced boric acid-based high-efficiency, environmentally friendly, phosphorus-free scale and corrosion inhibitor as follows:

[0115] S1. Prepare a water-soluble polyol-boric acid mixture. At 50° C., mix sorbitol and boric acid in a ratio of 2:1 and stir for 20 minutes. Add an alkaline buffer (sodium citrate) and adjust the pH to 6.0. Use ultrasonic dispersion (30kHz) for 15 minutes to promote complex formation. Cool to room temperature and filter to obtain a stable polyol-boric acid solution.

[0116] S2. Prepare the antiscalant solution, prepare 30% PESA solution (pH 7.5) and 30% PASP solution (pH 8.0); add PESA and PASP in stages under slow stirring (300 rpm), maintain the pH at 6.8-7.2, continue stirring for 30 minutes, and obtain a uniform antiscalant solution.

[0117] S3. Add corrosion inhibitor, and slowly add pH-responsive BTA microcapsules (PVP-coated) under stirring conditions; add pH-sensitive loaded zinc chloride (ZnCl2), and continue stirring for 30 minutes; filter and package to obtain the final scale and corrosion inhibitor product.

[0118] Example 4

[0119] This embodiment 4 provides a reinforced boric acid-based high-efficiency, environmentally friendly, phosphorus-free scale and corrosion inhibitor, which includes the following components in parts by weight:

[0120] Water-soluble polyol-boric acid mixture: 50 parts (sorbitol and boric acid in a ratio of 2:1); polyepoxysuccinic acid (PESA): 10 parts (30% solution); polyaspartic acid (PASP): 10 parts (30% solution); benzotriazole (BTA) microcapsules: 10 parts (PVP coating, spray drying method); zinc chloride (ZnCl2) pH sensitive load: 10 parts (chitosan-alginate complex load).

[0121] This embodiment 4 provides a method for preparing a reinforced boric acid-based high-efficiency, environmentally friendly, phosphorus-free scale and corrosion inhibitor as follows:

[0122] S1. Prepare a water-soluble polyol-boric acid mixture. At 50° C., mix sorbitol and boric acid in a ratio of 2:1 and stir for 20 minutes. Add an alkaline buffer (sodium citrate) and adjust the pH to 6.0. Use ultrasonic dispersion (30kHz) for 15 minutes to promote complex formation. Cool to room temperature and filter to obtain a stable polyol-boric acid solution.

[0123] S2. Prepare the antiscalant solution, prepare 30% PESA solution (pH 7.5) and 30% PASP solution (pH 8.0); add PESA and PASP in stages under slow stirring (300 rpm), maintain the pH at 6.8-7.2, continue stirring for 30 minutes, and obtain a uniform antiscalant solution.

[0124] S3. Add corrosion inhibitor, and slowly add pH-responsive BTA microcapsules (PVP-coated) under stirring conditions; add pH-sensitive loaded zinc chloride (ZnCl2), and continue stirring for 30 minutes; filter and package to obtain the final scale and corrosion inhibitor product.

[0125] Example 5

[0126] This embodiment 5 provides a reinforced boric acid-based high-efficiency, environmentally friendly, phosphorus-free scale and corrosion inhibitor, which includes the following components in parts by weight:

[0127] Water-soluble polyol-boric acid mixture: 70 parts (sorbitol and boric acid are in a ratio of 2:1); polyepoxysuccinic acid (PESA): 5 parts (30% solution); polyaspartic acid (PASP): 5 parts (30% solution); benzotriazole (BTA) microcapsules: 10 parts (PVP coating, spray drying method); zinc chloride (ZnCl2) pH sensitive load: 10 parts (chitosan-alginate complex load).

[0128] This embodiment 5 provides a method for preparing a reinforced boric acid-based high-efficiency, environmentally friendly, phosphorus-free scale and corrosion inhibitor as follows:

[0129] S1. Prepare a water-soluble polyol-boric acid mixture. At 50° C., mix sorbitol and boric acid in a ratio of 2:1 and stir for 20 minutes. Add an alkaline buffer (sodium citrate) and adjust the pH to 6.0. Use ultrasonic dispersion (30kHz) for 15 minutes to promote complex formation. Cool to room temperature and filter to obtain a stable polyol-boric acid solution.

[0130] S2. Prepare the antiscalant solution, prepare 30% PESA solution (pH 7.5) and 30% PASP solution (pH 8.0); add PESA and PASP in stages under slow stirring (300 rpm), maintain the pH at 6.8-7.2, continue stirring for 30 minutes, and obtain a uniform antiscalant solution.

[0131] S3. Add corrosion inhibitor, and slowly add pH-responsive BTA microcapsules (PVP-coated) under stirring conditions; add pH-sensitive loaded zinc chloride (ZnCl2), and continue stirring for 30 minutes; filter and package to obtain the final scale and corrosion inhibitor product.

[0132] Comparative Example 1

[0133] This comparative example 1 provides a reinforced boric acid-based high-efficiency, environmentally friendly, phosphorus-free scale and corrosion inhibitor, which includes the following components calculated by weight:

[0134] Boric acid mixture: 30 parts; polyepoxysuccinic acid (PESA): 25 parts (30% solution); polyaspartic acid (PASP): 25 parts (30% solution); benzotriazole (BTA) microcapsules: 10 parts (PVP coating, spray drying method); zinc chloride (ZnCl2) pH sensitive load: 10 parts (chitosan-alginate complex load).

[0135] This comparative example 1 provides a method for preparing a reinforced boric acid-based highly efficient, environmentally friendly, phosphorus-free scale and corrosion inhibitor as follows:

[0136] S1. Dissolve boric acid in water to obtain a boric acid solution.

[0137] S2. Prepare the antiscalant solution, prepare 30% PESA solution (pH 7.5) and 30% PASP solution (pH 8.0); add PESA and PASP in stages under slow stirring (300 rpm), maintain the pH at 6.8-7.2, continue stirring for 30 minutes, and obtain a uniform antiscalant solution.

[0138] S3. Add corrosion inhibitor, and slowly add pH-responsive BTA microcapsules (PVP-coated) under stirring conditions; add pH-sensitive loaded zinc chloride (ZnCl2), and continue stirring for 30 minutes; filter and package to obtain the final scale and corrosion inhibitor product.

[0139] Comparative Example 2

[0140] This comparative example 2 provides a reinforced boric acid-based high-efficiency, environmentally friendly, phosphorus-free scale and corrosion inhibitor, which includes the following components calculated by weight:

[0141] Water-soluble polyol-boric acid mixture: 30 parts (sorbitol and boric acid in a ratio of 2:1); polyaspartic acid (PASP): 25 parts (30% solution); benzotriazole (BTA) microcapsules: 10 parts (PVP coating, spray drying method); zinc chloride (ZnCl2) pH sensitive load: 10 parts (chitosan-alginate complex load).

[0142] This comparative example 2 provides a method for preparing a reinforced boric acid-based highly efficient, environmentally friendly, phosphorus-free scale and corrosion inhibitor as follows:

[0143] S1. Prepare a water-soluble polyol-boric acid mixture. At 50° C., mix sorbitol and boric acid in a ratio of 2:1 and stir for 20 minutes. Add an alkaline buffer (sodium citrate) and adjust the pH to 6.0. Use ultrasonic dispersion (30kHz) for 15 minutes to promote complex formation. Cool to room temperature and filter to obtain a stable polyol-boric acid solution.

[0144] S2. Prepare a scale inhibitor solution and prepare a 30% PASP solution (pH 8.0); add PASP in stages under slow stirring (300 rpm), maintain the pH at 6.8-7.2, and continue stirring for 30 minutes to obtain a uniform scale inhibitor solution.

[0145] S3. Add corrosion inhibitor, and slowly add pH-responsive BTA microcapsules (PVP-coated) under stirring conditions; add pH-sensitive loaded zinc chloride (ZnCl2), and continue stirring for 30 minutes; filter and package to obtain the final scale and corrosion inhibitor product.

[0146] Comparative Example 3

[0147] This comparative example 3 provides a reinforced boric acid-based high-efficiency, environmentally friendly, phosphorus-free scale and corrosion inhibitor, which includes the following components calculated by weight:

[0148] Water-soluble polyol-boric acid mixture: 30 parts (sorbitol and boric acid in a ratio of 2:1); polyepoxysuccinic acid (PESA): 25 parts (30% solution); benzotriazole (BTA) microcapsules: 10 parts (PVP coating, spray drying method); zinc chloride (ZnCl2) pH-sensitive load: 10 parts (chitosan-alginate complex load).

[0149] This embodiment 1 provides a method for preparing a reinforced boric acid-based high-efficiency, environmentally friendly, phosphorus-free scale and corrosion inhibitor as follows:

[0150] S1. Prepare a water-soluble polyol-boric acid mixture. At 50° C., mix sorbitol and boric acid in a ratio of 2:1 and stir for 20 minutes. Add an alkaline buffer (sodium citrate) and adjust the pH to 6.0. Use ultrasonic dispersion (30kHz) for 15 minutes to promote complex formation. Cool to room temperature and filter to obtain a stable polyol-boric acid solution.

[0151] S2. Prepare a scale inhibitor solution and prepare a 30% PESA solution (pH 7.5); add PESA in stages under slow stirring (300 rpm), maintain the pH at 6.8-7.2, and continue stirring for 30 minutes to obtain a uniform scale inhibitor solution.

[0152] S3. Add corrosion inhibitor, and slowly add pH-responsive BTA microcapsules (PVP-coated) under stirring conditions; add pH-sensitive loaded zinc chloride (ZnCl2), and continue stirring for 30 minutes; filter and package to obtain the final scale and corrosion inhibitor product.

[0153] Comparative Example 4

[0154] This comparative example 4 provides a reinforced boric acid-based high-efficiency, environmentally friendly, phosphorus-free scale and corrosion inhibitor, which includes the following components calculated by weight:

[0155] Water-soluble polyol-boric acid mixture: 30 parts (sorbitol and boric acid in a ratio of 2:1); polyepoxysuccinic acid (PESA): 25 parts (30% solution); polyaspartic acid (PASP): 25 parts (30% solution); zinc chloride (ZnCl2) pH sensitive load: 10 parts (chitosan-alginate complex load).

[0156] This comparative example 4 provides a method for preparing a reinforced boric acid-based highly efficient, environmentally friendly, phosphorus-free scale and corrosion inhibitor as follows:

[0157] S1. Prepare a water-soluble polyol-boric acid mixture. At 50° C., mix sorbitol and boric acid in a ratio of 2:1 and stir for 20 minutes. Add an alkaline buffer (sodium citrate) and adjust the pH to 6.0. Use ultrasonic dispersion (30kHz) for 15 minutes to promote complex formation. Cool to room temperature and filter to obtain a stable polyol-boric acid solution.

[0158] S2. Prepare the antiscalant solution, prepare 30% PESA solution (pH 7.5) and 30% PASP solution (pH 8.0); add PESA and PASP in stages under slow stirring (300 rpm), maintain the pH at 6.8-7.2, continue stirring for 30 minutes, and obtain a uniform antiscalant solution.

[0159] S3. Add the corrosion inhibitor, and slowly add the pH-sensitive loaded zinc chloride (ZnCl2) under stirring conditions, and continue stirring for 30 minutes; filter and package to obtain the final scale and corrosion inhibitor product.

[0160] Comparative Example 5

[0161] This comparative example 5 provides a reinforced boric acid-based high-efficiency, environmentally friendly, phosphorus-free scale and corrosion inhibitor, which includes the following components calculated by weight:

[0162] Water-soluble polyol-boric acid mixture: 30 parts (sorbitol and boric acid in a ratio of 2:1); polyepoxysuccinic acid (PESA): 25 parts (30% solution); polyaspartic acid (PASP): 25 parts (30% solution); benzotriazole (BTA) microcapsules: 10 parts (PVP coating, spray drying method).

[0163] This comparative example 5 provides a preparation method of a reinforced boric acid-based high-efficiency, environmentally friendly, phosphorus-free scale and corrosion inhibitor as follows:

[0164] S1. Prepare a water-soluble polyol-boric acid mixture. At 50° C., mix sorbitol and boric acid in a ratio of 2:1 and stir for 20 minutes. Add an alkaline buffer (sodium citrate) and adjust the pH to 6.0. Use ultrasonic dispersion (30kHz) for 15 minutes to promote complex formation. Cool to room temperature and filter to obtain a stable polyol-boric acid solution.

[0165] S2. Prepare the antiscalant solution, prepare 30% PESA solution (pH 7.5) and 30% PASP solution (pH 8.0); add PESA and PASP in stages under slow stirring (300 rpm), maintain the pH at 6.8-7.2, continue stirring for 30 minutes, and obtain a uniform antiscalant solution.

[0166] S3. Add the corrosion inhibitor, and slowly add the pH-responsive BTA microcapsules (PVP-coated) under stirring conditions, and continue stirring for 30 minutes; filter and package to obtain the final scale and corrosion inhibitor product.

[0167] Performance Testing

[0168] The scale and corrosion inhibitors prepared in Examples 1-5 and the comparative example were tested for scale inhibition performance. The water quality indicators of the water samples used in the test at 25°C were as follows: Ca 2+ 500mg / L, Mg 2+ 200mg / L, Cl - 200mg / L, HCO 3- 300mg / L, SO4 2- 200mg / L, pH 8.50; the dosing concentration during the test was 40mg / L, the water temperature was 80℃, and the test time was 16h; the scale inhibition rate was tested with reference to GB / T16632-2019 "Determination of scale inhibition performance of water treatment agents - calcium carbonate deposition method", and the corrosion inhibition rate was tested with reference to GB / T 18175-2014 "Determination of corrosion inhibition performance of water treatment agents - rotating coupon method" (the standard corrosion coupon was A3 carbon steel, constant temperature 40℃, and rotation speed of 100r / min for 168h). The specific experimental data are shown in Table 1.

[0169] Table 1 Experimental data

[0170]

[0171] The above description is only a preferred embodiment of the present invention and does not constitute any form of limitation to the present invention. Although the present invention has been presented as a preferred embodiment as above, it is not intended to limit the present invention. Any technician familiar with the profession can make some changes or modify the technical contents disclosed above into equivalent embodiments without departing from the scope of the technical solution of the present invention. However, any simple modification, equivalent change and modification made to the above embodiments based on the technical essence of the present invention without departing from the content of the technical solution of the present invention still falls within the scope of the technical solution of the present invention.

Claims

1. A reinforced boric acid-based high-efficiency, environmentally friendly, phosphorus-free scale and corrosion inhibitor, characterized in that: Calculated by weight, it includes the following components: 50-100 parts of water-soluble polyol-boric acid mixture, 0-50 parts of polyepoxysuccinic acid, 0-50 parts of polyaspartic acid, 0-50 parts of benzotriazole and 0-50 parts of zinc chloride.

2. The enhanced boric acid-based high-efficiency, environmentally friendly, phosphorus-free scale and corrosion inhibitor according to claim 1, characterized in that: In the water-soluble polyol-boric acid mixture, the ratio of the water-soluble polyol to the boric acid is 1-3.

3. The enhanced boric acid-based high-efficiency, environmentally friendly, phosphorus-free scale and corrosion inhibitor according to claim 2, characterized in that: The water-soluble polyol is any one of sorbitol, xylitol or glycerol or a mixture of several of them.

4. The enhanced boric acid-based high-efficiency, environmentally friendly, phosphorus-free scale and corrosion inhibitor according to claim 3, characterized in that: The preparation method of the water-soluble polyol-boric acid mixture is as follows: Mixing water-soluble polyol and boric acid at 40-60°C; Under stirring conditions, add an alkaline buffer to adjust the pH to 5.5-7.0; Use ultrasonic dispersion or high shear stirring; The mixture was cooled to room temperature and the insoluble matter was removed by filtration to obtain a solution of a polyol-boric acid mixture.

5. The enhanced boric acid-based high-efficiency, environmentally friendly, phosphorus-free scale and corrosion inhibitor according to claim 1, characterized in that: Pre-prepare a 30% solution of polyepoxysuccinic acid and a 30% solution of polyaspartic acid, and adjust the pH values ​​thereof to 7.0 to 8.5; Add polyepoxysuccinic acid and polyaspartic acid in stages under slow stirring; The pH value of the entire system was controlled to be maintained between 6.5 and 7.

5.

6. The enhanced boric acid-based high-efficiency, environmentally friendly, phosphorus-free scale and corrosion inhibitor according to claim 1, characterized in that: The pH-responsive microcapsules are formed by coating benzotriazole with polyvinyl pyrrolidone or gelatin-arabic gum system by spray drying or phase separation.

7. The enhanced boric acid-based high-efficiency, environmentally friendly, phosphorus-free scale and corrosion inhibitor according to claim 1, characterized in that: pH-sensitive polymer was used to load zinc chloride.

8. The enhanced boric acid-based high-efficiency, environmentally friendly, phosphorus-free scale and corrosion inhibitor according to claim 7, characterized in that: The pH sensitive polymer is polyacrylic acid or chitosan-alginate composite material.

9. The method for preparing a reinforced boric acid-based high-efficiency, environmentally friendly, phosphorus-free scale and corrosion inhibitor according to any one of claims 1 to 8, characterized in that: The steps include: Mixing a water-soluble polyol with boric acid at 40 to 60° C. to obtain a polyol-boric acid mixture solution; Adding 30% polyepoxysuccinic acid solution and 30% polyaspartic acid solution into the polyol-boric acid mixture solution, stirring evenly to obtain a scale inhibitor solution; Under stirring conditions, the prepared pH-responsive microcapsules and pH-sensitive polymer-loaded zinc chloride are slowly added to the scale inhibitor solution and stirred continuously.

10. The use of a reinforced boric acid-based high-efficiency, environmentally friendly, phosphorus-free scale and corrosion inhibitor according to any one of claims 1 to 8, characterized in that: The corrosion inhibitor is used in circulating cooling water.

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