Corrosion and scale inhibitor applicable to high-salinity water as well as preparation method and application of corrosion and scale inhibitor

Abstract

The invention discloses a corrosion and scale inhibitor suitable for high-salinity water quality and a preparation method and application thereof.The corrosion and scale inhibitor comprises nano SiO2 at NH2, organic phosphonate, zinc salt, polycarboxylic acid and nano SiO2, a corrosion inhibition component is composed of the nano SiO2 at NH2, the organic phosphonate and the zinc salt according to the mass ratio of (0.8-1.2): 0.5: (0.3-0.4), a scale inhibition component is composed of the polycarboxylic acid and the nano SiO2 according to the total solid content mass ratio of 3: 1, and the scale inhibition component is composed of the nano SiO2 at NH2, the organic phosphonate and the zinc salt. The polycarboxylic acid grafting rate in the scale inhibition component is greater than or equal to 80%, and the corrosion inhibition component and the scale inhibition component are compounded according to the ratio of 1: 1 to prepare a finished product agent; the preparation method comprises the following steps: preparing the corrosion inhibition component, adjusting the pH value to 3-4, preparing the scale inhibition component, and compounding the corrosion inhibition component and the scale inhibition component to prepare the finished product agent. According to the invention, nano SiO2 and NH2 are added to prepare a corrosion inhibition component, nano SiO2 is added to prepare a scale inhibition component, and the components are strictly mixed step by step, so that the components form a chemical and physical multi-synergistic corrosion and scale inhibition effect, and the finished agent has the characteristics of corrosion inhibition rate, CaCO3 resistance rate higher than 95%, MgSiO3 resistance rate higher than 80%, high-salt environment tolerance, high high-temperature stability, low biotoxicity and the like.

Description

Technical Field

[0001] The present invention belongs to the field of water treatment agents, and in particular relates to a corrosion and scale inhibitor suitable for high-salt water quality, a preparation method and an application thereof. Background Art

[0002] Groundwater resources are abundant in southern China, and most boilers use groundwater. However, groundwater is high in metal salts such as calcium, magnesium, and aluminum, as well as chloride ions, resulting in high water hardness. This can easily lead to boiler scaling and corrosion, particularly in high-temperature and high-pressure environments, where scaling and corrosion are more severe, directly impacting boiler efficiency and lifespan. Every year, a high percentage of boilers suffer tube bursts, drum bulging, and burnout due to scaling. In some areas, the average scale thickness can reach 2 to 8 mm. Because scale has a thermal conductivity of only 1% to 1.5% that of iron, it not only severely impacts boiler safety but also significantly wastes fuel. For example, a 0.5 mm thick scale layer increases energy consumption by 2%, while a 3 mm thick layer can increase energy consumption by 10%, and an 8 mm thick layer can increase energy consumption by as much as 35%.

[0003] At present, the most commonly used water treatment products on the market are organic phosphonate corrosion and scale inhibitors. Their scale inhibition mechanism is mainly the complexation between organic phosphonic acid and calcium and magnesium ions in water to form a stable complex with calcium and magnesium ions in water. This complex can remain soluble under different water temperature and pH conditions. However, when the salinity of the water is high or the concentration ratio is large, this type of corrosion and scale inhibitor is easily hydrolyzed or oxidatively decomposed, resulting in the formation of calcium phosphate precipitation, which causes the boiler to scale again. As a result, boiler users spend money to buy boiler water treatment products but cannot achieve the effect of scale removal or scale prevention. It may even further increase the phosphorus content in the water, causing water resource pollution after discharge and increasing the discharge water treatment costs of boiler users. Summary of the Invention

[0004] (1) Technical issues

[0005] The technical problem to be solved by the present invention is that existing water treatment products are unable to effectively deal with the boiler scaling and corrosion problems caused by high salt water quality. A new type of corrosion inhibitor and scale inhibitor and its preparation method are proposed, aiming to significantly improve the boiler operating efficiency and extend the service life.

[0006] (2) Technical solution

[0007] The present invention is achieved through the following technical solutions:

[0008] The present invention provides a corrosion and scale inhibitor suitable for high-salt water. The components of the corrosion and scale inhibitor include nano-SiO2@NH2, organic phosphonate, zinc salt, polycarboxylic acid, and nano-SiO2. The nano-SiO2@NH2, organic phosphonate, and zinc salt are mixed in a mass ratio of (0.8-1.2):0.5:(0.3-0.4) to form a corrosion inhibition component. The polycarboxylic acid and nano-SiO2 are mixed in a total solid content mass ratio of 3:1 to form a scale inhibition component. The grafting rate of the polycarboxylic acid in the scale inhibition component is ≥80%. The corrosion inhibition component and the scale inhibition component are compounded in a ratio of 1:1 to form a finished agent.

[0009] Based on the above formula, a corrosion inhibition component with a synergistic corrosion inhibition effect is formed by adding nano-SiO2@NH2 to conventional scale inhibitors such as organic phosphonates and zinc salts, and a scale inhibition component with a synergistic scale inhibition effect is formed by adding nano-SiO2 to conventional scale inhibitors such as polycarboxylic acids. The finished agent is prepared through secondary compounding of the corrosion inhibition component and the scale inhibition component. The finished agent has good synergistic effect of each component, is not easy to precipitate, and has high dispersion stability. When applied to high-salt water quality, it can form a continuous and dense corrosion inhibition film layer on the inner wall of the boiler, with the advantages of a corrosion inhibition rate of no more than 0.03mm / a, a corrosion inhibition rate and a CaCO3 inhibition rate higher than 95%, a MgSiO3 inhibition rate higher than 80%, tolerance to a high chlorine environment of 5000mg / L, high high-temperature stability, and low biological toxicity.

[0010] Preferably, the organic phosphonate is selected from one or more of hydroxyethylidene diphosphonic acid, hydroxyphosphonoacetic acid, ethylenediamine tetramethylenephosphonic acid, and dimethylphenylphosphonate, and the purity of the organic phosphonate is ≥98%, and the active component content is ≥50%.

[0011] Preferably, the zinc salt is zinc sulfate with a purity of ≥99.9%.

[0012] Preferably, the polycarboxylic acid is polyacrylic acid or acrylic acid copolymer, the polycarboxylic acid molecular weight is 2000-5000Da, and the solid content is ≥40%, so that the compounded corrosion and scale inhibitor can simultaneously achieve good effects of inhibiting calcium carbonate scale and magnesium silicate scale, thereby improving the applicable water quality range.

[0013] Preferably, the particle size of the nano-SiO2 in the nano-SiO2@NH2 and the nano-SiO2 in the scale inhibition component is 20-50 nm, and the specific surface area is 2200 m 2 / g, the surface hydroxyl density is 3 to 5 / nm 2 So that nano-SiO2 has good dispersion and provides sufficient adsorption sites and coordination sites, which is conducive to forming a more stable mixture morphology.

[0014] Preferably, the corrosion and scale inhibitor is further formulated with 1% mercaptobenzothiazole as a synergistic enhancer. Mercaptobenzothiazole bridges the corrosion and scale inhibition components, where the mercapto groups coordinate with the zinc and amino ions, and the benzene rings hydrophobically connect with the polycarboxylic acid, forming a stable composite micelle layer that can withstand temperatures of 120°C on the outside of the corrosion inhibition film. This further blocks scale growth and adhesion, enhancing the synergistic effect of corrosion and scale inhibition.

[0015] The present invention also provides a method for preparing a corrosion inhibitor and scale inhibitor suitable for high-salt water conditions, which comprises the following steps:

[0016] S1, raw material pretreatment: dissolving and diluting the organic phosphonate with deionized water to prepare a 30% organic phosphonate solution, and removing insoluble matter; purifying the polycarboxylic acid by dialysis to the target molecular weight;

[0017] S2, preparing the corrosion inhibition components: preparing the components according to the mass ratio of nano-SiO2@NH2, organic phosphonate and zinc salt in the ratio of (0.8-1.2):0.5:(0.3-0.4), first adding the zinc salt to the organic phosphonate solution and premixing evenly, then adding the nano-SiO2@NH2 to form a mixed solution; placing the mixed solution in a constant temperature water bath at 50±2°C and stirring at a stirring parameter of 200±10rpm for 2.0±0.1h; monitoring the pH value with an online pH meter during the stirring process, and adjusting the pH value with 10% HNO3 to control the pH value at 3.0-4.0, to obtain a homogeneous corrosion inhibition component solution with a transmittance of ≥95%;

[0018] S3, preparing the scale inhibition component: polycarboxylic acid and nano-SiO2 at a total solid content mass ratio of 3:1, pre-dispersing the nano-SiO2 in deionized water, adjusting the pH to 10 with NaOH, adding the polycarboxylic acid, and placing in an ice bath environment of ≤30°C, performing ultrasonic mixing at 40kHz for 15±1min to obtain a scale inhibition component solution with a polycarboxylic acid grafting rate ≥80%;

[0019] S4, compound activation: the corrosion inhibition component solution is added to the scale inhibition component solution at a flow rate of 5 mL / min and mixed evenly. The mixing mass ratio of the corrosion inhibition component solution to the scale inhibition component solution is 1:1. After mixing, ultrasonic activation is performed. The ultrasonic activation parameters are 20 kHz, 30 ± 1 min, and the temperature of the ultrasonic process is controlled at ≤ 40 ° C to obtain a stable composite micelle solution;

[0020] S5, finished product adjustment and preparation: the mixed solution prepared in step S4 is adjusted with 10% NaOH solution, the pH is controlled to 7.5-8.5, and the Na in the mixed solution is adjusted by reverse osmosis or ion exchange method. + The content is reduced to <0.1mol / L and the final product is obtained by aseptic filling.

[0021] Based on the above preparation method, by using organic phosphonate, Zn 2+ , nano-SiO2@NH2 is mixed and configured in a sequential gradient addition order, and the corrosion inhibition component and scale inhibition component are strictly configured step by step to form a stable complex. The pH of the corrosion inhibition component is adjusted to 3.0-4.0 before compounding. After the compounding is completed, the overall pH of the agent is adjusted again and the Na + content, avoiding direct polymerization and precipitation of zinc salt and polycarboxylic acid during the compounding process, and making the agent form a negative potential, preventing nano-SiO2@NH2 and nano-SiO2 from agglomerating and failing; the corrosion and scale inhibitor prepared by this preparation method has high stability, and is resistant to high temperature and high salt water, is not easy to hydrolyze and oxidatively decompose, and can form a continuous and stable corrosion and scale inhibition effect on the inner wall of the boiler after use.

[0022] Preferably, the method for obtaining nano-SiO2@NH2 in step S2 is: disperse nano-SiO2 in deionized water, adjust the pH to 4.5±0.2, heat to 60°C and keep constant temperature, add silane coupling agent and stir and mix, so that nano-SiO2 and the hydrolyzate of silane coupling agent undergo condensation reaction to obtain amino-modified SiO2@NH2. The surface of nano-SiO2 treated in this step can form a higher amino grafting rate, and the generated SiO2@NH2 can increase the corrosion inhibition rate of the agent by about 10%.

[0023] Preferably, in step S3, when pre-dispersing nano-SiO2, 0.1% polyethylene glycol PEG-400 is added as a dispersing aid to improve the pre-dispersion effect of nano-SiO2 and promote the bonding of nano-SiO2 and polycarboxylic acid to form a scale inhibition component solution with a high grafting rate.

[0024] Preferably, in step S4, the corrosion inhibition component and the scale inhibition component are mixed and placed in a light-proof environment, and 1.0±0.05% by mass of mercaptobenzothiazole, 9% of deionized water and 0.05% of butylated hydroxytoluene are first added and mixed, and then ultrasonic activation is performed. This step can further improve the compound stability of the corrosion inhibition component and the scale inhibition component by adding mercaptobenzothiazole as a synergistic enhancer, so that the finished agent exists in the form of composite micelles that can withstand high temperatures, which can further enhance the corrosion inhibition and scale inhibition effect in high-salt water.

[0025] The present invention also provides a corrosion and scale inhibitor suitable for use in high-salt boiler water. The dosage of the corrosion and scale inhibitor is determined based on a molar ratio of calcium ions to organic phosphonates in the boiler water of ≥1:1.2. The nano-SiO2@NH2 content in the added water is controlled to be 15% to 25%, and the zinc salt content is regulated based on the chloride ion content in the water. When the chloride content is 108 mg / L, the zinc salt content is no more than 8%. This dosage control method forms a continuous corrosion-inhibiting film on the inner wall of the boiler, maintains good dispersion stability, is less likely to form precipitation, and provides a more lasting corrosion and scale inhibition effect.

[0026] (3) Beneficial effects

[0027] Compared with existing corrosion and scale inhibitors, the corrosion and scale inhibitor of the present invention has the following beneficial effects:

[0028] 1) A corrosion inhibition component with a synergistic corrosion inhibition effect is formed by adding nano-SiO2@NH2 to conventional scale inhibitors such as organic phosphonates and zinc salts; a scale inhibition component with a synergistic scale inhibition effect is formed by adding nano-SiO2 to conventional scale inhibitors such as polycarboxylic acids; and a finished agent is obtained by secondary compounding of the corrosion inhibition component and the scale inhibition component. The finished agent has good synergistic effect of each component, is not easy to precipitate, and has high dispersion stability. When applied to high-salt water quality, a continuous and dense corrosion inhibition film layer can be formed on the inner wall of the boiler, with a corrosion inhibition rate of no more than 0.03 mm / a, a corrosion inhibition rate of more than 95%, a CaCO3 inhibition rate of more than 95%, and a MgSiO3 inhibition rate of more than 80%. The agent can withstand a high chlorine environment of 5000 mg / L, has high high-temperature stability, and has low biological toxicity.

[0029] 2) By adding mercaptobenzothiazole as a synergist in the compounding stage, the corrosion inhibition component and the scale inhibition component are bridged, and a stable composite micelle layer that can withstand 120°C is formed on the outside of the corrosion inhibition film layer, further blocking the growth and adhesion of scale, and improving the synergistic effect and high-temperature stability of corrosion and scale inhibition.

[0030] 3) By using organic phosphonates, Zn 2+ , nano-SiO2@NH2 is mixed and configured in a sequential gradient addition order, and the corrosion inhibition component and scale inhibition component are strictly configured step by step to form a stable complex. The pH of the corrosion inhibition component is adjusted to 3.0-4.0 before compounding. After the compounding is completed, the overall pH of the agent is adjusted again and the Na + content, avoiding direct polymerization and precipitation of zinc salt and polycarboxylic acid during the compounding process, and making the agent form a negative potential, preventing nano-SiO2@NH2 and nano-SiO2 from agglomerating and failing; the corrosion and scale inhibitor prepared by this preparation method has high stability, and is resistant to high temperature and high salt water, is not easy to hydrolyze and oxidatively decompose, and can form a continuous and stable corrosion and scale inhibition effect on the inner wall of the boiler after use.

[0031] 4) By adjusting the amount of corrosion and scale inhibitor added according to the calcium ion content and chloride ion content of the added water, the effect of the corrosion and scale inhibitor can be guaranteed, and a continuous corrosion inhibition film layer can be further formed on the inner wall of the boiler, and better dispersion stability can be maintained, which is not easy to form precipitation and the duration of corrosion and scale inhibition can be increased.

[0032] The mechanism of action of the corrosion and scale inhibitor of the present invention includes:

[0033] (1) Synergistic corrosion inhibition of corrosion inhibition components, specifically including:

[0034] a) The silanol (-SiOH) on the surface of nano-SiO2@NH2 forms a Si-O-Fe covalent bond with the Fe element in the boiler metal matrix, thereby forming a continuous corrosion inhibition chemical film layer on the inner wall of the boiler to achieve a corrosion inhibition effect;

[0035] b) Through the protonation of some amino groups (-NH2) in nano-SiO2@NH2 to -NH3 + Then with the phosphonate (-PO3 2- ) electrostatic adsorption to form SiO2@NH3 + -O3P-PBTCA complex, which improves the adsorption capacity of organic phosphonates and corrosion inhibition film;

[0036] c) Chelating free Fe in boiler water by organic phosphonates 2+ Mg 2+ , Ca 2+ Forming soluble complexes further increases the film thickness and achieves synergistic corrosion inhibition effect;

[0037] d) The potential ζ is regulated to +28mV by protonation of the amino group (-NH2) in nano-SiO2@NH2 to adsorb Cl in high-salt boiler water. - , reduce high levels of Cl - Pitting corrosion risk to the boiler metal matrix;

[0038] e) Part of the silanol groups (-SiOH) on the surface of nano-SiO2@NH2 and Zn 2+ Generate Zn(OH)2 and deposit on the surface of nano-SiO2@NH2, inhibiting the reduction of dissolved oxygen in boiler water, thereby inhibiting the cathode reaction on the boiler metal matrix, further enhancing the corrosion inhibition effect;

[0039] (2) Synergistic scale inhibition effect of scale inhibition components: The porous structure of nano-SiO2 with high specific surface area provides Mg 2+ , Ca 2+It can be used as the adsorption growth site of free metal ions, and wrap scale crystal nuclei such as CaCO3 by grafting high molecular weight polycarboxylic acid with nano-SiO2, inhibiting the further growth of scale crystal nuclei and achieving scale inhibition effect;

[0040] (3) Synergistic corrosion and scale inhibition effect of corrosion and scale inhibition components: Nano-SiO2 without grafted polycarboxylic acid and free Zn 2+ The reaction produces [ZnSO3] + Colloids fill the vacancy defects of the passivation film, enhance the density and toughness of the passivation film, prevent scale substances from depositing on the surface of the boiler wall to form scale, and further achieve synergistic corrosion and scale inhibition effects.

[0041] (4) The synergistic effect of mercaptobenzothiazole: the mercapto group is coordinated with the zinc ion and the amino ion, and the benzene ring is hydrophobically connected with the polycarboxylic acid, forming a further bridge between the corrosion inhibition component and the scale inhibition component, and forming a stable composite micelle layer that can withstand 120 ° C outside the corrosion inhibition film layer, further blocking the growth and adhesion of scale, and improving the synergistic effect of corrosion inhibition and scale inhibition. BRIEF DESCRIPTION OF THE DRAWINGS

[0042] Figure 1 It is a flow chart of the preparation method of the present invention. DETAILED DESCRIPTION

[0043] The present invention will be further described in detail below with reference to the examples, but the embodiments of the present invention are not limited thereto.

[0044] Example 1

[0045] The present embodiment provides a corrosion inhibitor and scale inhibitor suitable for high-salt water, the effective components of which include nano-SiO2@NH2, organic phosphonate, zinc salt, polycarboxylic acid, nano-SiO2, and the balance is deionized water, wherein the nano-SiO2@NH2, organic phosphonate and zinc salt are in a mass ratio of (0.8-1.2):0.5:(0.3-0.4) to form a corrosion inhibitor component, and the polycarboxylic acid and nano-SiO2 are in a total solid content mass ratio of 3:1 to form a scale inhibitor component, the polycarboxylic acid grafting rate in the scale inhibitor component is ≥80%, and the corrosion inhibitor component and the scale inhibitor component are compounded in a 1:1 ratio to form a finished agent.

[0046] The organic phosphonate is selected from one or more of hydroxyethylidene diphosphonic acid, hydroxyphosphonoacetic acid, ethylenediamine tetramethylenephosphonic acid, and dimethylphenylphosphonate. The purity of the organic phosphonate is ≥98%, and the active ingredient content is ≥50%. In this embodiment, hydroxyethylidene diphosphonic acid (HEDP) is preferred because its molecular structure contains a CP bond and has good antioxidant properties. It can capture oxidizing components such as free oxygen in the water to be treated. At the same time, its molecular weight and structure are more conducive to chelating calcium and magnesium ions, resulting in higher synergistic scale and corrosion inhibition.

[0047] The zinc salt is zinc sulfate with a purity of ≥99.9%.

[0048] The polycarboxylic acid is polyacrylic acid or an acrylic acid copolymer, the molecular weight of the polycarboxylic acid is 2000-5000Da, and the solid content is ≥40%. In this embodiment, polyacrylic acid is preferably used, which has a more suitable molecular weight. At the same time, the linear structure can be adsorbed on the surface of scale crystal nuclei such as calcium carbonate and magnesium silicate and wrap the scale crystal nuclei, preventing the crystal nuclei from growing, and then forming irregular fine particles to achieve a scale inhibition effect.

[0049] The nano-SiO2 in the nano-SiO2@NH2 and the nano-SiO2 in the scale inhibition component are selected to have a particle size of 20 to 50 nm and a specific surface area of ​​2200 m 2 / g, the surface hydroxyl density is 3 to 5 / nm 2 , ensuring that nano-SiO2 has good dispersion and provides sufficient adsorption sites and coordination sites.

[0050] The ratio of the corrosion inhibition component and the scale inhibition component in the corrosion and scale inhibitor of this embodiment is based on:

[0051] (1) Control standard of the amount of nano-SiO2@NH2 added in the corrosion inhibition component: when it is less than 0.8 parts, the corrosion inhibition film on the surface of the boiler metal substrate has poor continuity and the corrosion inhibition rate is less than 85%; when it is greater than 1.2 parts, the dispersion of the finished agent after compounding decreases and the agent shows micro-agglomeration phenomenon (DLS>200nm measured by 600nm spectrophotometry);

[0052] (2) Control standard of zinc salt addition in corrosion inhibition component: when it is less than 0.3 parts, the potential shifts to the right by 10mV after compounding, and the dispersion stability of the agent is less than 7 days; when it is greater than 0.4 parts, the free Zn + The content is too high, and - ZnCl2 microparticle precipitation is generated, and the dispersion stability of the drug is less than 7 days;

[0053] Scale inhibition component ratio control standard: When the addition amount of polycarboxylic acid (using PAA as an example) is greater than 3 parts, the scale inhibition rate of calcium carbonate is greater than 98%, but the scale inhibition rate of magnesium silicate is less than 70%. When the addition amount of nano-SiO2 is greater than 1 part, the viscosity of the compounded agent increases (Brookfield viscosity>50CP), making it difficult to pump the agent when added. Specifically, the ratio of each component of the corrosion and scale inhibitor of this embodiment is as follows:

[0054] Corrosion inhibition components: 1 part of nano-SiO2@NH2 (20% of the content in the water to be treated); 0.5 part of organic phosphonate (10% of the content in the water to be treated), 0.3 part of zinc salt (6% of the content in the water to be treated), and the balance is deionized water;

[0055] Scale inhibition components: 1.5 parts of polycarboxylic acid (30% of the content in the water to be treated), 0.5 parts of nano-SiO2 (10% of the content in the water to be treated), and the balance is deionized water;

[0056] Compound: 1 part of corrosion inhibition component; 1 part of scale inhibition component

[0057] Example 2

[0058] The difference between the distribution ratio of each component of the corrosion and scale inhibitor in this embodiment and that in Example 1 is:

[0059] The amount of nano-SiO2@NH2 in the corrosion inhibition component is 0.8 parts (the content in the water to be treated is 16%), and the other components are the same as those in Example 1.

[0060] Example 3

[0061] The difference between the distribution ratio of each component of the corrosion and scale inhibitor in this embodiment and that in Example 1 is:

[0062] The amount of nano-SiO2@NH2 in the corrosion inhibition component is 1.2 parts (the content in the water to be treated is 24%), and the other components are the same as those in Example 1.

[0063] Example 4

[0064] The difference between the distribution ratio of each component of the corrosion and scale inhibitor in this embodiment and that in Example 1 is:

[0065] On the basis of the proportions of Example 1, 0.05 parts of 1% mercaptobenzothiazole were added, and the rest were the same as in Example 1.

[0066] Example 5

[0067] This embodiment provides comparative examples 1 to 4 of the corrosion and scale inhibitors of embodiments 1 to 4:

[0068] Comparative Example 1: No nano-SiO2@NH2 was added to the corrosion inhibition component, and the remaining components were the same as in Example 1.

[0069] Comparative Example 2: In the scale inhibition component, PAA: nano-SiO2=2:1, that is, the solid content of nano-SiO2 in the scale inhibition component is greater than 30%, and the other components are the same as in Example 1.

[0070] Comparative Example 3: PAA: nano-SiO2 in the scale inhibition component is 4:1, that is, the solid content of PAA in the scale inhibition component is greater than 75%, and the other components are the same as in Example 1.

[0071] Example 6

[0072] This embodiment provides a method for preparing a corrosion inhibitor and scale inhibitor suitable for high-salt water, which is used to prepare the corrosion inhibitors and scale inhibitors of Examples 1 to 4 and Comparative Examples 1 to 4 of Example 5:

[0073] S1, raw material pretreatment: dissolving and diluting the organic phosphonate with deionized water to prepare a 30% organic phosphonate solution, and removing insoluble matter; purifying the polycarboxylic acid by dialysis to the target molecular weight;

[0074] S2, preparing the corrosion inhibition component: preparing the components of nano-SiO2@NH2, organic phosphonate and zinc salt according to the mass ratio of Examples 1 to 4 and Comparative Example 1, first adding the zinc salt to the organic phosphonate solution and premixing evenly, then adding the nano-SiO2@NH2 to form a mixed solution; placing the mixed solution in a constant temperature water bath at 50±2°C and stirring at a stirring parameter of 200±10rpm for 2.0±0.1h, monitoring the pH with an online pH meter during the stirring process, and adjusting the pH with 10% HNO3 to a pH of 3.0-4.0, to obtain a homogeneous corrosion inhibition component solution with a transmittance of ≥95%;

[0075] S3. Prepare the scale inhibition component: prepare polycarboxylic acid and nano-SiO2 according to the total solid content mass ratio of Examples 1 to 4 and Comparative Example 3 / 4. Pre-disperse the nano-SiO2 in deionized water, adjust the pH to 10 with NaOH, add the polycarboxylic acid, place in an ice bath at ≤30°C, and perform ultrasonic mixing at 40 kHz for 15±1 min to obtain a scale inhibition component solution with a polycarboxylic acid grafting rate ≥80%.

[0076] S4, compound activation: the corrosion inhibition component solution is added to the scale inhibition component solution at a flow rate of 5 mL / min and mixed evenly. The mixing mass ratio of the corrosion inhibition component solution to the scale inhibition component solution is 1:1. After mixing, ultrasonic activation is performed. The ultrasonic activation parameters are 20 kHz, 30 ± 1 min, and the temperature of the ultrasonic process is controlled at ≤ 40 ° C to obtain a stable composite micelle solution;

[0077] S5, finished product adjustment and preparation: the mixed solution prepared in step S4 is adjusted with 10% NaOH solution, the pH is controlled to 7.5-8.5, and the Na in the mixed solution is adjusted by reverse osmosis or ion exchange method. + The content is reduced to <0.1mol / L and the final product is obtained by aseptic filling.

[0078] Among them, the method for obtaining nano-SiO2@NH2 in step S2 is: disperse nano-SiO2 in deionized water, adjust the pH to 4.5±0.2, heat to 60°C and keep the temperature constant, add silane coupling agent and stir and mix, so that nano-SiO2 and the hydrolyzate of the silane coupling agent undergo condensation reaction to obtain amino-modified SiO2@NH2.

[0079] Take KH-550 (γ-aminotriethoxysilane) as a silane coupling agent as an example:

[0080] The condensation reaction formula of KH-550 with SiO2 surface -SiOH after hydrolysis is:

[0081] SiO2-0H+NH2(CH2)3Si(OC2H5)3→SiO2-0-Si(CH2)3NH2+3C2H5OH

[0082] The chemical formula of SiO2 after modification is: SiO2@NH2 (core structure: SiO2 surface grafted with -(CH2)3NH2)

[0083] Furthermore, in step S3, when pre-dispersing the nano-SiO2, 0.1% polyethylene glycol PEG-400 is added as a dispersing aid to improve the pre-dispersion effect of the nano-SiO2.

[0084] Furthermore, when preparing the corrosion inhibitor and scale inhibitor of Example 4, in step S4, the corrosion inhibitor component and the scale inhibitor component are mixed and placed in a light-proof environment, and 1.0±0.05% by mass of mercaptobenzothiazole, 9% by mass of deionized water and 0.05% by mass of butylated hydroxytoluene are first added and mixed, and then ultrasonic activation is performed.

[0085] The key control process of the preparation method of this embodiment is:

[0086] (1) When configuring the corrosion inhibition components, organic phosphonate, Zn 2+ , nano-SiO2@NH2 is added in a gradient order for mixing, and the pH is adjusted to 3.0-4.0;

[0087] (2) Strictly configure the corrosion inhibition component and the scale inhibition component step by step so that they each form a stable complex, and then add the corrosion inhibition component to the scale inhibition component for compounding;

[0088] (3) After compounding, adjust the overall pH of the agent again and control the Na + The content is lower than 0.1 mol / L, so that the ζ potential of the finished drug is at a stable polarization potential point of -20 mV, ensuring the dispersion stability of the finished drug and prolonging the duration of the effect.

[0089] The zeta potential change state during the preparation process is shown in Table 1 below:

[0090] Table 1 Correspondence between regulatory factors and potential changes

[0091]

[0092] The corrosion and scale inhibitors of Examples 1 to 4 prepared according to the preparation method of Example 6 and Comparative Examples 1 to 4 were added to the experimental water and mixed evenly, and then the performance was tested. The corrosion inhibition rate was tested by a carbon steel rotating coupon test with reference to GB / T18175-2000, and the scale inhibition rate was tested by a static scale inhibition test with reference to GB / T16632-2008. The dispersion stability was tested by HPLC for 48 hours after static placement for 30 days.

[0093] Table 2: Experimental water quality indicators

[0094]

[0095] Table 3: Comparison of scale inhibition effect test

[0096] Reagents <![CDATA[CaCO3 inhibition rate (%)]]> <![CDATA[MgSiO3 resistivity (%)]]> Dispersion stability (30d) Comparative Example 3 92.3 65.2 5% precipitation Example 1 98.1 82.7 Transparent, no precipitation Comparative Example 4 98.7 78.4 Increased viscosity

[0097] From the comparative data in Table 3, it can be seen that the corrosion and scale inhibitors of Examples 1 to 4 (the above data are average data of at least 3 tests) have good corrosion and scale inhibition effects.

[0098] The corrosion and scale inhibition performance of Example 1 was further tested, wherein the high-temperature dispersion stability was tested by 48h HPLC, the chloride ion tolerance was tested by a rotating coupon test in a simulated high-chloride environment (5000mg / L), and the decrease in corrosion inhibition rate was used as the characterization index, and the biological toxicity was tested by a fish median lethal dose test with reference to GB / T21761-2011.

[0099] Table 4: Other performance test results of Example 1:

[0100]

[0101]

[0102] As can be seen from the results in the above table, the corrosion and scale inhibitor of the present invention also has better high-temperature stability, high-salt water tolerance and low biological toxicity, is suitable for high-salt water treatment and is environmentally friendly.

[0103] Example 7

[0104] This embodiment provides an application of a corrosion inhibitor and scale inhibitor suitable for high-salt water in high-salt boiler water. The corrosion inhibitor and scale inhibitor of the present invention is added to the boiler water to be treated in the following manner:

[0105] The amount of corrosion and scale inhibitor added is determined based on the molar ratio of calcium ions to organic phosphonates (PBTCA) in boiler water ≥1:1.2, and the content of nano-SiO2@NH2 in the added water is controlled to 15% to 25%. The zinc salt content is adjusted according to the chloride ion content in the water. When the chlorine content in the reference water is 108 mg / L, the zinc salt content is adjusted to no more than 8%.

[0106] After the addition, carbon steel coupons were used to monitor the water for one month (30 days). The summary results of the actual dosage of the corrosion and scale inhibitor and the final corrosion and scale inhibition effect are shown in Table 6.

[0107] Table 5: Dosage of corrosion and scale inhibitors and their effects

[0108]

[0109]

[0110] As shown in the results in the above table, the monitoring results show that the corrosion inhibition rate can reach more than 95%, the CaCO3 inhibition rate can reach more than 95%, and the MgSiO3 inhibition rate can reach more than 80%. There is no corrosion or scaling on the inner wall of the boiler, and there is no turbidity or flocculants in the water. The corrosion and scale inhibitor of this embodiment has a good corrosion and scale inhibition effect in high-salt water quality.

[0111] The above description is merely a preferred embodiment of the present invention and does not limit the technical scope of the present invention. Therefore, any minor modifications, equivalent changes and modifications made to the above embodiments based on the technical essence of the present invention still fall within the scope of protection of the present invention.

Claims

1. A corrosion and scale inhibitor suitable for high salinity water, characterized in that Its components include nano-SiO2@NH2, organic phosphonate, zinc salt, polycarboxylic acid, and nano-SiO2, wherein nano-SiO2@NH2, organic phosphonate and zinc salt constitute a corrosion inhibition component in a mass ratio of (0.8~1.2):0.5:(0.3~0.4), polycarboxylic acid and nano-SiO2 constitute a scale inhibition component in a total solid content mass ratio of 3:1, the polycarboxylic acid grafting rate in the scale inhibition component is ≥80%, and the corrosion inhibition component and the scale inhibition component are compounded in a 1:1 ratio to form a finished agent.

2. The corrosion and scale inhibitor suitable for high-salt water according to claim 1, characterized in that: The organic phosphonate is selected from one or more of hydroxyethylidene diphosphonic acid, hydroxyphosphonoacetic acid, ethylenediamine tetramethylenephosphonic acid, and dimethylphenylphosphonate. The purity of the organic phosphonate is ≥98%, and the active component content is ≥50%.

3. The corrosion and scale inhibitor suitable for high-salt water according to claim 1, characterized in that: The polycarboxylic acid is polyacrylic acid or acrylic acid copolymer, the molecular weight of the polycarboxylic acid is 2000-5000 Da, and the solid content is ≥40%.

4. The corrosion and scale inhibitor suitable for high-salt water according to claim 1, characterized in that: The particle size of the nano-SiO2 is 20-50 nm, and the specific surface area is 2200 m 2 / g, the surface hydroxyl density is 3~5 / nm 2 .

5. The corrosion and scale inhibitor suitable for high-salt water according to claim 1, characterized in that: The corrosion and scale inhibitor is further compounded with 1% of mercaptobenzothiazole as a synergistic enhancer.

6. A method for preparing a corrosion inhibitor and scale inhibitor suitable for high-salt water, for preparing the corrosion inhibitor and scale inhibitor suitable for high-salt water as claimed in claim 1, characterized in that The following steps are involved: S1, raw material pretreatment: dissolving and diluting the organic phosphonate with deionized water to prepare a 30% organic phosphonate solution, and removing insoluble matter; purifying the polycarboxylic acid to the target molecular weight by dialysis; S2, prepare the corrosion inhibition components: prepare the components according to the mass ratio of nano-SiO2@NH2, organic phosphonate and zinc salt (0.8~1.2):0.5:(0.3~0.4), first add the zinc salt to the organic phosphonate solution and premix evenly, then add the nano-SiO2@NH2 to form a mixed solution; the mixed solution is placed in a constant temperature water bath at 50±2°C and stirred at 200±10rpm for 2.0±0.1h. During the stirring process, an online pH meter is used for monitoring, and the pH is adjusted to 3.0~4.0 with 10% HNO3 to obtain a homogeneous corrosion inhibition component solution with a transmittance of ≥95%; S3, preparing the scale inhibition component: polycarboxylic acid and nano-SiO2 at a total solid content weight ratio of 3:1, pre-dispersing the nano-SiO2 in deionized water, adjusting the pH to 10 with NaOH, adding the polycarboxylic acid, and placing in an ice bath at ≤30°C. Ultrasonic mixing was performed at 40 kHz for 15±1 min to obtain a scale inhibition component solution with a polycarboxylic acid grafting rate ≥80%; S4, compound activation: the corrosion inhibition component solution is added to the scale inhibition component solution at a flow rate of 5 mL / min and mixed evenly. The mixing mass ratio of the corrosion inhibition component solution to the scale inhibition component solution is 1:

1. After mixing, ultrasonic activation is performed. The ultrasonic activation parameters are 20 kHz, 30 ± 1 min, and the temperature of the ultrasonic process is controlled at ≤ 40 ° C to obtain a stable composite micelle solution; S5, finished product adjustment and preparation: the mixed solution prepared in step S4 is adjusted with 10% NaOH solution, the pH is controlled at 7.5-8.5, and the Na in the mixed solution is adjusted by reverse osmosis or ion exchange method. + The content is reduced to <0.1mol / L and the final product is obtained by aseptic filling.

7. The method for preparing a corrosion and scale inhibitor suitable for high-salt water according to claim 6, characterized in that: The method for obtaining nano-SiO2@NH2 in step S2 is: disperse nano-SiO2 in deionized water, adjust the pH to 4.5±0.2, heat to 60°C and keep constant temperature, add silane coupling agent and stir and mix, so that nano-SiO2 and the hydrolyzate of silane coupling agent undergo condensation reaction to obtain amino-modified SiO2@NH2.

8. The method for preparing a corrosion and scale inhibitor suitable for high-salt water according to claim 6, characterized in that: In step S3, when pre-dispersing nano-SiO2, 0.1% polyethylene glycol PEG-400 is added as a dispersing aid.

9. The method for preparing a corrosion and scale inhibitor suitable for high-salt water according to claim 6, characterized in that: In step S4, the corrosion inhibition component and the scale inhibition component are mixed and placed in a light-proof environment, and 1.0±0.05% by mass of mercaptobenzothiazole, 9% by mass of deionized water and 0.05% by mass of butylated hydroxytoluene are first added and mixed, and then ultrasonic activation is performed.

10. The use of a corrosion inhibitor and scale inhibitor suitable for high-salt water in high-salt boiler water according to claim 1, characterized in that: The addition amount of the corrosion inhibitor and scale inhibitor is determined based on the molar ratio of calcium ions to organic phosphonates in boiler water being ≥1:1.2, wherein the content of nano-SiO2@NH2 in the added water is controlled to be 15%~25%, and the zinc salt content is regulated according to the chloride ion content in the water. When the chlorine content in the water is 108 mg / L, the zinc salt content is not more than 8%.

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