Scale and corrosion inhibitor for seawater circulating cooling water

Abstract

The invention relates to the field of water treatment, and discloses a scale and corrosion inhibitor for seawater circulating cooling water, which is prepared from phosphonic acid grafted maleic anhydride-acrylic acid copolymer, hydroxyethylidene diphosphonic acid, amino trimethylene phosphonic acid, N, N-dimethylformamide, N, N-dimethylformamide, N, N-dimethylformamide, N, N-dimethylformamide, N, N- The anti-corrosion coating is prepared from the following raw materials: N, N-diethylaminomethyl-benzotriazole, gamma-aminopropyltriethoxysilane, zinc salt and a polyoxyethylene-polyoxypropylene block copolymer. The core of the invention is that all the raw material components form the thermo-sensitive polyelectrolyte compound through a self-assembly process. The compound is stably dispersed at low temperature by utilizing the cloud point effect of the block copolymer, and is subjected to phase change and preferential deposition on a high-temperature heat exchange surface, so that targeted and efficient delivery of various active components is realized. According to the invention, the problems of incompatibility of components and poor stability of a traditional compound agent are solved, the product has excellent storage stability, and efficient and synergistic corrosion and scaling control can be realized under high-temperature and high-salinity working conditions.

Description

TECHNICAL FIELD

[0001] The present application relates to the technical field of water treatment, in particular to a scale and corrosion inhibitor for seawater circulating cooling water. BACKGROUND

[0002] Seawater cooling systems are widely used in power, chemical, shipping and other industries. The high concentration of chlorides, sulfates and calcium, magnesium hardness ions in seawater makes the system continuously face the technical challenges of corrosion and fouling. Therefore, developing a scale and corrosion inhibition technology that can stably operate in this medium environment is one of the core topics in this field.

[0003] To address the above challenges, the prior art mostly uses compounded water treatment agents. However, the chemical incompatibility between the functional components in the agent is a technical obstacle. For example, when the cationic zinc salt as an inhibitor coexists with the anionic organic phosphonate as a scale inhibitor, it is easy to react to form insoluble precipitates. This phenomenon not only reduces the effective concentration of active components, but also causes secondary pollution, affecting the storage stability and performance of the formula.

[0004] In addition, the conventional method of adding agents is to maintain a certain concentration in the entire water body, but the scaling and corrosion process mainly occurs at the high-temperature solid-liquid interface of heat exchangers and other equipment. This non-targeted protection mode results in insufficient concentration of effective components on the surface of key equipment. In order to achieve the expected inhibition effect, the overall dosage must be increased, which not only increases the operating cost, but also fails to achieve efficient protection of key equipment.

[0005] At the same time, in a complex system containing multiple metal materials, the existing agent is difficult to provide comprehensive synergistic protection. The efficiency of some polymer scale inhibitors decreases in high-hardness water bodies, while commonly used zinc salt inhibitors are effective for carbon steel but lack protection ability for copper alloys. This makes it difficult to form a stable protective film that can simultaneously inhibit multiple fouling and protect different metals in a mixed material system, thereby affecting the overall reliability and operating life of the system. SUMMARY

[0006] The technical problem to be solved by the present application is to provide a scale and corrosion inhibitor for seawater circulating cooling water that can achieve targeted delivery to the surface of heat exchange equipment and synergistically control corrosion and fouling in a seawater cooling water system with high temperature and high salinity.

[0007] To solve the above technical problems, the present application provides a scale and corrosion inhibitor for seawater circulating cooling water, which adopts the following technical solution: A scale and corrosion inhibitor for seawater circulating cooling water is made from raw materials containing the following weight parts: Phosphonic acid-based grafted maleic anhydride-acrylic acid copolymer 100-115 parts; Hydroxyethylidene diphosphonic acid 28-40 parts; Aminotrimethylenephosphonic acid 50-75 parts; N,N-diethylaminomethyl-benzotriazole 8-15 parts; Gamma-aminopropyltriethoxysilane 30-45 parts; Zinc salt 40-55 parts; Polyoxyethylene-polyoxypropylene block copolymer 20-35 parts.

[0008] By adopting the technical scheme, the application co-assembles various functional scale and corrosion inhibition components through specific preparation process to form a kinetic stable temperature-sensitive polyelectrolyte composite (T-PEC) colloidal dispersion system. The core innovation mechanism of the system lies in its environmental responsiveness, and the specific process is described as follows. Construction of the composite: First, the anionic components such as phosphonic acid group grafted maleic anhydride-acrylic acid copolymer with carboxyl and phosphonic acid group, hydroxyethylidene diphosphonic acid, aminotrimethylenephosphonic acid and the like are pre-mixed with N,N-diethylaminomethyl-benzotriazole to form a negative charge-rich anionic polyelectrolyte prepolymer.

[0009] Meanwhile, the gamma-aminopropyltriethoxysilane is hydrolyzed under acidic conditions to generate a positively charged protonated amino group (-NH3 + ) and a complexing silanol group (-Si-OH). Subsequently, the zinc salt is introduced, and the zinc ion (Zn 2+ ) is complexed with the above-mentioned groups to form a stable cationic complex prepolymer.

[0010] Finally, in the presence of the polyoxyethylene-polyoxypropylene block copolymer as a co-assembly medium, the electrostatic attraction between the anionic and cationic prepolymers drives the controlled self-assembly of the components, and finally forms the temperature-sensitive polyelectrolyte composite. The block copolymer plays a role in space stabilization in the composite, preventing direct precipitation of incompatible components.

[0011] Targeted release mechanism: In the circulating water main body (such as pipes, water tanks) at a relatively low temperature, the composite is dispersed in the water in the form of stable colloids, and each active component is bound inside the colloidal structure, maintaining a low free concentration.

[0012] When the circulating water flows through the surface of high-temperature equipment such as heat exchangers, the local water temperature rises and exceeds the cloud point temperature of the polyoxyethylene-polyoxypropylene block copolymer. The block copolymer undergoes phase transition, and the molecular chain changes from a hydrophilic state to a hydrophobic state and shrinks, resulting in the destruction of the stability of the entire composite colloidal structure.

[0013] The unstable complex preferentially adsorbs and deposits at the solid-liquid interface at high temperature, thereby realizing in-situ release of high-concentration scale and corrosion inhibitor active components at the heat exchange surface most in need of protection, and achieving targeted and efficient delivery of the active substances.

[0014] Therefore, the technical scheme of the present application provides multiple incompatible active components, solves the problems of poor stability of conventional compounded agents and insufficient concentration of effective components in critical areas, and improves the comprehensive protection performance under harsh working conditions.

[0015] Preferably, the phosphonic acid group grafted maleic anhydride-acrylic acid copolymer is obtained by polymerization of maleic anhydride and acrylic acid as comonomers, and the molar ratio of maleic anhydride:acrylic acid in the comonomers is (2-4):(6-8).

[0016] By adopting the above technical scheme, the molar ratio ensures that the copolymer main chain has sufficient maleic anhydride unit-derived rigid structure and strong calcium ion chelation sites, while the acrylic acid unit provides good water dispersibility, and the synergistic effect of the two optimizes the scale inhibition performance and system compatibility of the polymer.

[0017] Preferably, the mass ratio of the phosphonic acid group grafted maleic anhydride-acrylic acid copolymer to the total solid content of the hydroxyethylenediphosphonic acid and the aminotri(methylene) phosphonic acid is (0.85-1.4):1.

[0018] By adopting the above technical scheme, the copolymer in the molecular weight range has excellent scale inhibition and dispersion capacity and suitable viscosity. If the molecular weight is too low, the scale inhibition efficiency and film forming property will decrease; if the molecular weight is too high, the water dispersibility will be poor, which is not conducive to the formation of stable complexes.

[0019] Preferably, the preparation method of the phosphonic acid group grafted maleic anhydride-acrylic acid copolymer comprises: after copolymerization of maleic anhydride and acrylic acid, phosphorous acid and formaldehyde are added to carry out grafting reaction, so as to introduce phosphonic acid groups on the copolymer molecular chain.

[0020] By adopting the above technical scheme, the phosphonic acid groups introduced on the side chain of the polymer are not only high-efficiency scale inhibition active functional groups, but also provide additional negative charge sites, thereby enhancing the electrostatic interaction force between the phosphonic acid groups and the cationic complex pre-polymer, which is conducive to the formation of a more stable polyelectrolyte complex.

[0021] Preferably, the N,N-diethylaminomethyl-benzotriazole is prepared from benzotriazole, diethylamine and formaldehyde under Mannich reaction conditions.

[0022] By adopting the technical scheme, the solubility and dispersibility of benzotriazole in water phase system are improved through Mannich amine methylation modification, so that the benzotriazole can be uniformly integrated into an anion prepolymer, and the benzotriazole can be targeted to be delivered to the surface of brass and other copper alloys together with the whole composite system to play an effective corrosion inhibition effect.

[0023] Preferably, the zinc salt is zinc sulfate or zinc sulfate heptahydrate.

[0024] By adopting the technical scheme, zinc sulfate is a commonly used and cost-effective zinc source in industry, which can stably provide zinc ions as a cathodic corrosion inhibitor.

[0025] Preferably, the cloud point temperature of the polyoxyethylene-polyoxypropylene block copolymer in an aqueous solution is 35-50℃.

[0026] By adopting the technical scheme, the cloud point temperature range is highly matched with the working characteristics of an industrial circulating cooling water system. The main body water temperature of the system is usually lower than 35℃, and the surface temperature of the heat exchanger is generally higher than 40℃. This setting ensures that the composite remains stable in the main circulating pipeline and triggers a response only in the target area (the heat exchange surface), achieving precise targeted control.

[0027] Preferably, the mass ratio of the hydroxyethylidene diphosphonic acid to the amino trimethylene phosphonic acid is 1:(1.6-2.1). By adopting the technical scheme, the hydroxyethylidene diphosphonic acid and the amino trimethylene phosphonic acid are two kinds of complementary organic phosphonates. When they are compounded in this specific mass ratio range, a synergistic effect can be produced, and excellent inhibition effect on various scales such as calcium carbonate and calcium phosphate can be exhibited.

[0028] Preferably, the weight ratio of the gamma-aminopropyl triethoxysilane to the zinc salt is 1:(1.2-1.5). By adopting the technical scheme, the hydrolyzed gamma-aminopropyl triethoxysilane can provide sufficient coordination groups to form a stable complex with zinc ions. This not only prevents free zinc ions from directly reacting with phosphonate and other components to generate precipitates, but also constitutes a cationic prepolymer with corrosion inhibition function and positive charge, which is the key to the subsequent electrostatic self-assembly step.

[0029] Preferably, the raw material components form a temperature-sensitive polyelectrolyte composite with the polyoxyethylene-polyoxypropylene block copolymer as a co-assembly medium.

[0030] By adopting the technical scheme, the final existence form of the product is defined. This composite structure is the physical basis for realizing all the technical effects of the present application, which organizes various independent chemical components into a whole with functional synergy and environmental responsiveness.

[0031] In summary, the present application comprises at least one of the following beneficial technical effects: 1. The scale and corrosion inhibitor provided by the present application has excellent storage stability. By co-assembling oppositely charged anion and cation prepolymers in the presence of polyoxyethylene-polyoxypropylene block copolymer, a kinetically stable polyelectrolyte complex is formed, which physically separates zinc salt and phosphonate and other incompatible components in a homogeneous system, effectively avoiding their direct contact and precipitation reaction during product preparation and storage, and ensuring the performance stability of the product after long-term storage.

[0032] 2. The product of the present application realizes targeted protection of the surface of heat exchange equipment, improves the scale and corrosion inhibition efficiency, and utilizes the temperature-sensitive properties of the polyoxyethylene-polyoxypropylene block copolymer in the complex. When the medicament flows through the high-temperature heat exchange surface, the complex undergoes phase transition and loses stability due to the local temperature exceeding its cloud point, and preferentially deposits on the high-temperature solid-liquid interface. This process efficiently enriches phosphonic acid-based graft copolymer, organic phosphonate, zinc salt, and copper corrosion inhibitor and other active components in the area most prone to fouling and corrosion, thereby achieving synergistic and efficient inhibition effect at a lower overall dosage concentration.

[0033] 3. The present application provides broad-spectrum and synergistic protection capability for various materials and fouling through scientific compounding and structure of multiple components. Phosphonic acid-based graft maleic anhydride-acrylic acid copolymer is compounded with various organic phosphonates, which has excellent inhibition and dispersion ability for calcium carbonate and other hard fouling. The complex formed by γ-aminopropyl triethoxysilane and zinc salt as a cationic corrosion inhibitor can form a protective film on the metal surface. N,N-diethylaminomethyl-benzotriazole provides special protection for copper alloy materials. Each component synergistically acts under the targeted release mechanism, realizing comprehensive and long-acting corrosion and fouling control for mixed material systems such as carbon steel and copper alloy. DETAILED DESCRIPTION

[0034] Preparation Examples 1-3: Preparation Example 1: Preparation of phosphonic acid-based graft maleic anhydride-acrylic acid copolymer (PMAA-PA): Into a 1000 mL four-necked flask equipped with a mechanical stirrer, a thermometer, a reflux condenser and a constant pressure dropping funnel, 300 g of deionized water was added. The stirring was started and the flask was heated to bring the water temperature to 80°C. 60 g of maleic anhydride and 110 g of acrylic acid (molar ratio of monomers about 3:7) were mixed well in advance; 15 g of ammonium persulfate was dissolved in 50 g of deionized water to prepare an initiator solution. The mixed monomers and the initiator solution were respectively charged into two constant pressure dropping funnels and were added into the flask at a constant rate and simultaneously over a period of 3 hours. After the addition was completed, the reaction was continued at 80°C for 2 hours. After the reaction was completed, the temperature of the system was lowered to 65°C and 15 g of phosphorous acid was added and stirred until it was completely dissolved. Subsequently, 15 g of formaldehyde solution with a mass fraction of 37% was added dropwise through a constant pressure dropping funnel over a period of 30 minutes. After the addition was completed, the temperature of the system was slowly raised to 100°C and the reaction was continued at this temperature for 4 hours. After the reaction was completed, the heating was stopped and the system was naturally cooled to room temperature to obtain a light yellow transparent polymer aqueous solution. The solid content of the solution was 35.2 wt% and the number average molecular weight (Mn) of the polymer was 3500 g / mol.

[0035] Preparation Example 2: Preparation of phosphonic acid group grafted maleic anhydride-acrylic acid copolymer (PMAA-PA): The basic operation steps and the amounts of raw materials were the same as in Preparation Example 1, except that the amount of initiator ammonium persulfate was reduced to 10 g and the temperature of the copolymerization reaction was controlled at 90°C. The remaining reaction conditions, grafting reaction steps and the amounts of raw materials were the same as in Preparation Example 1. After the reaction was completed, the system was cooled to room temperature to obtain a light yellow transparent polymer aqueous solution. The solid content of the solution was 35.5 wt% and the number average molecular weight (Mn) of the polymer was 7500 g / mol.

[0036] Preparation Example 3: Preparation of N,N-diethylaminomethyl-benzotriazole (BTA-DEAM): In a 500 mL three-necked flask equipped with a mechanical stirrer, a thermometer and a constant pressure dropping funnel, 119 g (1.0 mol) of benzotriazole and 80 g (1.1 mol) of diethylamine were dissolved in 200 mL of isopropyl alcohol to form a homogeneous solution. The reaction flask was placed in an ice-water bath and the internal temperature was lowered to below 5°C. Then, 90 g (1.1 mol) of 37% aqueous formaldehyde solution was slowly added dropwise through the constant pressure dropping funnel within 2 hours, and the internal temperature was strictly controlled to be no more than 15°C during the dropping process. After the dropping was completed, the ice-water bath was removed and the reaction system was continuously stirred at room temperature (25°C) for 20 hours. After the reaction was completed, the reaction solution was transferred to a rotary evaporator and distilled under reduced pressure at 60°C and -0.09 MPa to remove the solvent isopropyl alcohol and unreacted raw materials. Finally, a yellowish oily liquid product was obtained, which was N,N-diethylaminomethyl-benzotriazole.

[0037] Examples 1-3: Example 1: In a reaction kettle, 250 g of the phosphonic acid group grafted maleic anhydride-acrylic acid copolymer (PMAA-PA) aqueous solution prepared in Preparation Example 1 was added, followed by sequentially adding 40 g of 60% hydroxyethylidene diphosphonic acid (HEDP) aqueous solution, 80 g of 50% amino trimethylene phosphonic acid (ATMP) aqueous solution, and 5 g of N,N-diethylaminomethyl-benzotriazole (BTA-DEAM) prepared in Preparation Example 3, and stirring was started until the components were completely dissolved and uniformly mixed. Using a 30% sodium hydroxide solution, the pH of the mixture was slowly adjusted to 8.5 to obtain an anionic polyelectrolyte prepolymer (A solution).

[0038] In another reaction kettle, 20 g of γ-aminopropyl triethoxysilane (γ-APS) was added to 100 g of deionized water, and the pH of the system was adjusted to 3.5 using a 10% hydrochloric acid solution under stirring, and hydrolysis was performed at this pH for 30 minutes. Subsequently, 30 g of zinc sulfate heptahydrate was pre-dissolved in 50 g of deionized water, and the obtained zinc sulfate solution was slowly pumped into the above-mentioned γ-APS hydrolysis solution, and stirred to obtain a cationic complex prepolymer (B solution).

[0039] 10 g of polyoxyethylene-polyoxypropylene block copolymer (L64) was dissolved in 100 g of deionized water to form a temperature-sensitive co-assembly medium (C solution).

[0040] Formation of temperature-sensitive polyelectrolyte complex (T-PEC): The C solution prepared in Step 3 was added to the reaction kettle containing the A solution, mixed well, and the system temperature was adjusted to 20°C. High-speed stirring was started, and the B solution prepared in Step 2 was added at a constant rate over 30 minutes through a metering pump. The pH of the system was monitored in real time during the addition and maintained at 7.0-7.5 using dilute sodium hydroxide solution. After the addition was completed, stirring was continued for 30 minutes for maturation. Finally, deionized water was added to make up the balance, so that the total weight of the product was 1000 g. The seawater circulating cooling water scale and corrosion inhibitor product of this example was finally obtained.

[0041] Example 2: In a reaction kettle, 300 g of the phosphonic acid-based grafted maleic anhydride-acrylic acid copolymer (PMAA-PA) aqueous solution prepared in Preparation Example 1 (with a monomer MA to AA molar ratio of 3:7) was added, followed by the addition of 50 g of a 60% by mass hydroxyethylenediphosphonic acid (HEDP) aqueous solution, 120 g of a 50% by mass amino-tris-methylene phosphonic acid (ATMP) aqueous solution (at this point, the mass ratio of HEDP to ATMP solid content was 1:2), and 10 g of the N,N-diethylaminomethyl-benzotriazole (BTA-DEAM) prepared in Preparation Example 3. Stirring was started until the components were completely dissolved and mixed well. Using a 30% by mass sodium hydroxide solution, the pH of the mixture was slowly adjusted to 9.0, and an anionic polyelectrolyte prepolymer (A solution) was obtained.

[0042] In another reaction kettle, 35 g of γ-aminopropyltriethoxysilane (γ-APS) was added to 150 g of deionized water, and using a 10% by mass hydrochloric acid solution, the pH of the system was adjusted to 4.0 while stirring, and hydrolysis was continued at this pH for 45 minutes. Subsequently, 45 g of zinc sulfate heptahydrate was pre-dissolved in 80 g of deionized water, and the resulting zinc sulfate solution was slowly pumped into the above-mentioned γ-APS hydrolysis solution, stirred well, and a cationic complex prepolymer (B solution) was obtained.

[0043] 25 g of polyoxyethylene-polyoxypropylene block copolymer (L64) was dissolved in 150 g of deionized water, and stirred until completely dissolved, to obtain a temperature-sensitive co-assembly medium (C solution).

[0044] Formation of temperature-sensitive polyelectrolyte complex (T-PEC): The C solution prepared in Step 3 was added to the reactor containing the A solution, mixed well, and the temperature of the system was adjusted to 25°C. High speed stirring was started, and the B solution prepared in Step 2 was added dropwise into the reactor at a constant rate over 20 minutes. The pH of the system was maintained at 7.5-8.0 by using dilute sodium hydroxide solution during the addition. After the addition was completed, the stirring was continued for 45 minutes for maturation. Finally, deionized water was added to make up the total weight of the product to 1000 g. The product of the seawater circulating cooling water scale and corrosion inhibitor of the example was obtained.

[0045] Example 3: In a reactor, 350 g of the high molecular weight phosphonate grafted maleic anhydride-acrylic acid copolymer (PMAA-PA) aqueous solution prepared in Preparation Example 2 was added, followed by the addition of 80 g of a 60% by weight hydroxyethylenediphosphonic acid (HEDP) aqueous solution, 192 g of a 50% by weight amino-tris-methylene phosphonic acid (ATMP) aqueous solution (at this time, the mass ratio of HEDP to ATMP was 1:2), and 20 g of the N,N-diethyl aminomethyl-benzotriazole (BTA-DEAM) prepared in Preparation Example 3. Stirring was started until the components were completely dissolved and mixed well. The pH of the mixture was slowly adjusted to 9.5 using a 30% by weight sodium hydroxide solution to obtain an anionic polyelectrolyte prepolymer (A solution).

[0046] In another reactor, 50 g of γ-aminopropyl triethoxysilane (γ-APS) was added to 200 g of deionized water, and the pH of the system was adjusted to 4.5 using a 10% by weight hydrochloric acid solution while stirring, and the hydrolysis was continued for 60 minutes at this pH. Subsequently, 60 g of zinc sulfate heptahydrate was previously dissolved in 100 g of deionized water, and the resulting zinc sulfate solution was slowly pumped into the above-mentioned γ-APS hydrolysis solution, and stirred to obtain a cationic complex prepolymer (B solution).

[0047] 40 g of polyoxyethylene-polyoxypropylene block copolymer (L64) was dissolved in 200 g of deionized water to obtain a temperature-sensitive co-assembly medium (C solution).

[0048] Formation of the temperature-sensitive polyelectrolyte complex (T-PEC): The C solution prepared in Step 3 was added to the reactor containing the A solution, mixed well, and the temperature of the system was adjusted to 25°C. High speed stirring was started, and the B solution prepared in Step 2 was added dropwise into the reactor at a constant rate over 20 minutes. The pH of the system was maintained at 7.5-8.0 by using dilute sodium hydroxide solution during the addition. After the addition was completed, the stirring was continued for 45 minutes for maturation. Finally, deionized water was added to make up the total weight of the product to 1000 g. The product of the seawater circulating cooling water scale and corrosion inhibitor of the example was obtained.

[0049] Comparative Examples 1-5: Comparative Example 1: Comparative Example 2:

[0050] Comparative Example 2: Comparative Example 2:

[0051] Comparative Example 3: Comparative Example 3:

[0052] Comparative Example 4: Comparative Example 4:

[0053] Comparative Example 5: Comparative Example 5:

[0054] Test Examples 1-5: Test Example 1: The test examples are aimed to evaluate the physical stability of the scale and corrosion inhibitors prepared in the examples of the present application and the samples prepared in the comparative examples, especially their anti-precipitation and anti-delamination abilities under accelerated aging conditions.

[0055] Experimental Procedure: Each of 100 mL of the samples prepared in Example 1, Example 2, Example 3, Comparative Example 1 and Comparative Example 2 was placed in a clean, dry 100 mL glass bottle with a stopper, and the bottle mouth was sealed.

[0056] The initial turbidity of each sample was measured at room temperature using a turbidimeter, and the initial appearance state was recorded by visual observation.

[0057] All the sealed sample bottles were placed in a constant temperature oven at (50 ± 2) °C for thermal storage accelerated aging test, with a duration of 7 days (168 hours).

[0058] After the thermal storage was completed, all the sample bottles were taken out and naturally cooled to 25 °C at room temperature.

[0059] The appearance state of each sample after cooling was observed and recorded by visual observation, with a focus on whether there were any stratification, flocculation or precipitates.

[0060] After the sample was thoroughly shaken (if there was any precipitate, only the supernatant was taken), its turbidity was measured again using a turbidimeter.

[0061] The change rate of the turbidity of each sample was calculated according to the following formula: Turbidity change rate (%) = [(turbidity after storage - initial turbidity) / initial turbidity] x 100% Experimental data: Table 1. Test results of thermal storage stability of samples Note: The sample of Comparative Example 1 formed a large amount of precipitate immediately after preparation, and was a heterogeneous system, so it could not be effectively measured for turbidity.

[0062] Conclusion: The test data in Table 1 show that the samples of Example 1, 2 and 3 remained uniform in appearance and had a turbidity change rate of less than 7% after being stored at 50 °C for 7 days. The components of Comparative Example 1 produced precipitate immediately after mixing, and could not form a stable product. The sample of Comparative Example 2 produced precipitate after thermal storage, and the turbidity value increased significantly. This result shows that the preparation process of pre-complexing zinc ions with hydrolyzed silane and performing self-assembly in stages can effectively avoid direct precipitation reactions between active components. This process integrates chemically incompatible components into a kinetically stable liquid phase system, and a product with thermal storage stability is obtained.

[0063] Test Example 2: This test example aims to verify whether the scale and corrosion inhibitor prepared in the embodiments of the present application has a change in physical properties triggered by temperature changes in an aqueous solution, and to confirm the source of this property by comparing it with a comparative example that does not contain a temperature-sensitive component.

[0064] Experimental procedure: Sample preparation: Accurately pipette 1.00 mL of the sample prepared in Example 2 and Comparative Example 3, respectively, into a 100 mL volumetric flask, dilute to the mark with deionized water and shake well to prepare a 1.0% by mass solution to be tested.

[0065] Instrument setup: Connect a jacketed glass sample cell with a magnetic stir bar and a temperature sensor to a thermostatic water bath circulator. Immerse the fiber optic probe of the turbidimeter into the sample cell, ensuring that the measurement light path is not disturbed by air bubbles.

[0066] Temperature ramping measurement: Inject 50 mL of the solution to be tested into the sample cell and start the magnetic stirring. Set the initial temperature of the thermostatic water bath circulator to 25°C and record the initial turbidity after the temperature in the sample cell stabilizes.

[0067] Programmatically increase the temperature at a rate of 2°C / 5 min from 25°C to 55°C. After stabilizing for 2 minutes at each temperature point (25, 27, 29,..., 55°C), record the actual temperature in the sample cell and the corresponding turbidity value simultaneously.

[0068] Repeat the measurement three times for each sample and take the average value.

[0069] Experimental data: Table 2. Turbidity test data of sample dilutions as a function of temperature Conclusion: The test data in Table 2 show that the dilution of the sample of Example 2 exhibits a sharp increase in turbidity in the temperature interval from 37°C to 43°C and maintains a high value plateau at higher temperatures. The sample of Comparative Example 3 exhibits a weak, approximately linear increase in turbidity over the entire test temperature range. The abrupt behavior of the turbidity of the sample of Example 2 is consistent with the lower critical solution temperature (LCST) characteristic of block copolymers as temperature-sensitive co-assembly media. This data supports the presence of a temperature-triggered physical phase transition mechanism in the product of the present invention, which is attributed to the introduction of temperature-sensitive components.

[0070] Test Example 3: This test example aims to evaluate the ability of the scale and corrosion inhibitor prepared in the example of the present invention to inhibit the formation of calcium carbonate scale in a high-temperature, high-hardness static water body, and to compare its performance with multiple comparative examples.

[0071] Experimental procedure: Preparation of experimental water sample: Dissolve analytical pure calcium chloride, magnesium chloride, sodium bicarbonate and sodium chloride in deionized water in a beaker to prepare a total hardness (as CaCO3) of 550 mg / L (of which Ca2+ is 200 mg / L, Mg2+ is 350 mg / L). 2+Simulated seawater with a concentration of 240 mg / L, a total alkalinity (calculated as CaCO3) of 600 mg / L, and a chloride ion concentration of 15000 mg / L.

[0072] Sample addition: Take several 250mL stoppered conical flasks and add 100mL of the above-mentioned simulated seawater to each. Set up a blank sample without any treatment agent. Add the samples of Examples 1-3, Comparative Examples 1, 3, and 4 to the remaining conical flasks respectively, so that the final concentration of the treatment agent is 20mg / L.

[0073] Constant temperature scaling: Place all conical flasks in a constant temperature water bath at (80±1)℃ and heat for 10 hours to accelerate the precipitation process of calcium carbonate.

[0074] Sample preparation and determination: After the isothermal period, remove the conical flasks from the water bath and cool them to room temperature. Filter the water samples in each flask using a 0.45 μm filter membrane to remove the generated calcium carbonate precipitate.

[0075] The filtrate was accurately transferred, and the concentration of residual calcium ions in the filtrate was determined by titration with disodium ethylenediaminetetraacetate (EDTA).

[0076] Scale inhibition rate calculation: The scale inhibition rate η of each sample is calculated according to the following formula: η(%)=[(C2-C0) / (C1-C0)]×100% Where, C0 is the calcium ion concentration (mg / L) in the blank sample filtrate; C1 is the initial calcium ion concentration (mg / L) in the simulated seawater before the experiment; C2 is the calcium ion concentration (mg / L) in the experimental sample filtrate with added treatment agent.

[0077] Experimental data: Table 3. Evaluation results of static scale inhibition performance Note: The blank sample does not contain scale inhibitor, and its results are used as the benchmark for calculating the scale inhibition rate, so the scale inhibition rate index is not applicable.

[0078] in conclusion: The test data in Table 3 show that the static scale inhibition rates of Examples 1, 2, and 3 for calcium carbonate all exceed 91%, which is higher than that of the comparative examples. Comparative Example 1, due to component precipitation failure, has a scale inhibition rate close to zero. Comparative Example 3, lacking the temperature-sensitive co-assembled medium, has lower scale inhibition performance than the examples. Comparative Example 4, using a conventional polymer, also has lower scale inhibition performance than the examples of this invention. These results indicate that the specific structure of the copolymer, the multi-component compound system, and the polyelectrolyte composite structure formed through the co-assembly process of this invention are the reasons for its high static scale inhibition performance.

[0079] Test Example 4: This test case aims to simulate the dynamic operating environment of an industrial circulating cooling water system and evaluate the comprehensive scale inhibition and corrosion inhibition performance of the product of the present invention under continuous flow and heat exchange conditions, especially the synergistic protection effect on two typical metal materials, carbon steel and brass.

[0080] Experimental steps: Coupling preparation: 20# carbon steel and H62 brass coupons with dimensions of 50mm × 25mm × 2mm were selected. They were sequentially subjected to degreasing, pickling, neutralization, rinsing with deionized water, dehydration with anhydrous ethanol, and cold air drying. The initial mass of each coupon was accurately weighed using an analytical balance and recorded to the nearest 0.1mg.

[0081] Dynamic simulation device: A set of circulating water dynamic simulation device is adopted, which includes a water storage tank, circulating pump, flow meter, plate test section and a simulated heat exchange tube section with built-in heating rod.

[0082] Experimental parameter settings: The simulated seawater prepared in Test Example 3 was added to the water storage tank. The system operating parameters were set as follows: the circulating water flow rate was 0.5 m / s, the main water temperature was controlled at (45±1)℃, the simulated heat exchange tube surface temperature was controlled at (55±2)℃, and the system concentration factor was maintained at 3.0.

[0083] Experimental Procedure: Pretreated carbon steel and brass plates were installed in the plate test section. The device was started, and after the system stabilized, 50 mg / L of samples from Example 2, Comparative Example 3, and Comparative Example 4 were added to different batches of experimental water. A blank sample without any treatment was also included. The experiment was run continuously for 120 hours.

[0084] Performance evaluation: Corrosion rate determination: After the experiment, the pads were removed. Corrosion products and scale on the surface of the pads were removed using the chemical cleaning method in GB / T18175-2000 standard, followed by rinsing, drying, and weighing. The annual corrosion rate was calculated based on the weight loss of the pads.

[0085] Scaling determination: The simulated heat exchange tube was removed and dried in an oven at 105°C until constant weight. Its mass was accurately measured, and the amount of scale deposited per unit area was calculated by comparing it with the mass before the experiment.

[0086] Experimental data Table 4. Evaluation results of dynamic simulation corrosion and scaling performance in conclusion: Table 4 shows the dynamic simulation test results, indicating that under the conditions of Example 2, the corrosion rates of carbon steel and brass, as well as the amount of scale deposited on the heat exchanger tube surface, were lower than those of the blank sample and the comparative examples. This performance improvement can be attributed to the product's temperature-sensitive characteristics. When circulating water flows through the higher-temperature heat exchange surface, it triggers a phase change in the polyelectrolyte complex, leading to an increase in the concentration of the active component in that region, thereby achieving a more effective scale inhibition and corrosion inhibition effect at the heat exchange interface. The performance data of Comparative Example 3, which lacks the temperature-sensitive component, also indirectly supports this explanation.

[0087] Test Example 5: This test example aims to directly verify the temperature-sensitive targeted enrichment behavior of the active components in the product of this invention by quantitatively analyzing the deposition amount of corrosion-inhibiting components on the surface at different temperatures.

[0088] Experimental steps: Experimental setup construction: A micro-circulation loop consisting of a room temperature section and a local heating section was constructed. The room temperature section maintains the water temperature at (25±1)℃ through natural convection; the heating section uses an external heating jacket to precisely control the inner wall surface temperature at (50±1)℃.

[0089] Hanger placement: Pre-treated and weighed 20# carbon steel hangers are pre-placed inside the ambient temperature section and the heating section respectively.

[0090] Experimental procedure: Simulated seawater containing 200 mg / L of the sample from Example 2 and 200 mg / L of the sample from Comparative Example 3 was prepared. The prepared solutions were injected into the micro-circulation loops, and the circulation pumps were started to circulate the solutions in the loops at a low speed for 2 hours.

[0091] Sample collection and processing: After the experiment, stop the circulation and carefully remove all the trays. Gently rinse the surface of the trays with plenty of deionized water to remove any loosely adhered substances.

[0092] Place each tablet in a clean beaker, add 10 mL of 2% dilute nitric acid solution, and sonicate for 15 minutes to completely wash away the deposits on the surface of the tablet.

[0093] Collect all the eluent and bring the volume to 25 mL with deionized water in a volumetric flask.

[0094] Elemental analysis: The concentration of zinc (Zn) in each eluent was determined by inductively coupled plasma optical emission spectrometry (ICP-OES), and the amount of zinc deposited per unit area of ​​the substrate was calculated accordingly.

[0095] Experimental data Table 5. Analysis results of zinc deposition on the surface of the pads Sample No. Test Section Zinc deposit (pg / cm 2 ) <!-- 13 -->]]> Example 2 Heated Section (50°C) 15.8 Example 2 Ambient Section (25°C) 1.9 Comparative Example 3 Heated Section (50°C) 3.2 Comparative Example 3 Ambient Section (25°C) 2.9 in conclusion: The data in Table 5 show that when using the sample from Example 2, the zinc deposition on the surface of the heating section (50°C) plate was 15.8 μg / cm³. 2 The deposition rate was significantly higher than that at room temperature (25℃) (1.9 μg / cm³). 2 For Comparative Example 3, which does not contain the temperature-sensitive component, there was no significant difference in zinc deposition between the heated and room-temperature sections. The selective enrichment of zinc on high-temperature surfaces, as a marker of the corrosion inhibition system, is consistent with the temperature-sensitive targeted delivery mechanism proposed in this invention. This result indicates that the polyelectrolyte composite structure of the product tends to deposit on high-temperature surfaces above its phase transition temperature.

Claims

1. A scale and corrosion inhibitor for seawater circulating cooling water, characterized in that, Made from the following ingredients in parts by weight: 100-115 parts of phosphonic acid-grafted maleic anhydride-acrylic acid copolymer; 28-40 parts of hydroxyethylidene diphosphonic acid; 50-75 parts of aminotrimethylenephosphonic acid; 8-15 parts of N,N-diethylaminomethyl-benzotriazole; 30-45 parts of γ-aminopropyltriethoxysilane; 40-55 parts zinc salt; 20-35 parts of polyoxyethylene-polyoxypropylene block copolymer.

2. The scale and corrosion inhibitor for seawater circulating cooling water according to claim 1, characterized in that, The phosphonic acid-grafted maleic anhydride-acrylic acid copolymer is obtained by polymerization of maleic anhydride and acrylic acid as comonomers, wherein the molar ratio of maleic anhydride to acrylic acid in the comonomer is (2-4):(6-8).

3. The scale and corrosion inhibitor for seawater circulating cooling water according to claim 1, characterized in that, The mass ratio of the total solid content of the phosphonic acid-grafted maleic anhydride-acrylic acid copolymer to that of the hydroxyethylidene diphosphonic acid and the aminotrimethylene phosphonic acid is (0.85-1.4):

1.

4. The scale and corrosion inhibitor for seawater circulating cooling water according to claim 1, characterized in that, The preparation method of the phosphonic acid-grafted maleic anhydride-acrylic acid copolymer includes: After maleic anhydride and acrylic acid are copolymerized, phosphorous acid and formaldehyde are added for grafting, thereby introducing phosphonic acid groups into the copolymer molecular chain.

5. The scale and corrosion inhibitor for seawater circulating cooling water according to claim 1, characterized in that, The N,N-diethylaminomethyl-benzotriazole is prepared by benzotriazole, diethylamine and formaldehyde under Mannich reaction conditions.

6. The scale and corrosion inhibitor for seawater circulating cooling water according to claim 1, characterized in that, The zinc salt is zinc sulfate or zinc sulfate heptahydrate.

7. The scale and corrosion inhibitor for seawater circulating cooling water according to claim 1, characterized in that, The turbidity point temperature of the polyoxyethylene-polyoxypropylene block copolymer in aqueous solution is 35-50℃.

8. The scale and corrosion inhibitor for seawater circulating cooling water according to claim 1, characterized in that, The solid content mass ratio of the hydroxyethylidene diphosphonic acid to aminotrimethylene phosphonic acid is 1:(1.6-2.1).

9. The scale and corrosion inhibitor for seawater circulating cooling water according to claim 1, characterized in that, The weight ratio of the γ-aminopropyltriethoxysilane to the zinc salt is 1:(1.2-1.5).

10. A scale and corrosion inhibitor for seawater circulating cooling water according to claim 1, characterized in that, The corrosion inhibitor is prepared by the following steps: (a) The phosphonic acid-grafted maleic anhydride-acrylic acid copolymer, hydroxyethylidene diphosphonic acid, aminotrimethylene phosphonic acid and N,N-diethylaminomethyl-benzotriazole are mixed, and the pH of the mixture is adjusted to 8.5-9.5 to form an anionic prepolymer; (b) The γ-aminopropyltriethoxysilane is hydrolyzed under acidic conditions of pH 3.5-4.5 for 30-60 minutes and then complexed with the zinc salt to form a cationic complex prepolymer; (c) In the presence of the polyoxyethylene-polyoxypropylene block copolymer, at a temperature of 20-30°C, the cationic complex prepolymer obtained in step (b) is added to the anionic prepolymer obtained in step (a), and the pH value of the system is maintained in the range of 7.0-8.0 during the addition process to form a polyelectrolyte complex.

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