Nano-penetrating resin coating for anticorrosion construction of desulfurization chimney lining in high-humidity water environment

Abstract

The application discloses a kind of nano-permeable resin coating for construction in high-humidity water environment of desulfurization chimney lining anticorrosion, chimney lining includes reducing agent layer, reinforcing agent layer, primer layer, topcoat layer in turn from inside to outside, nano-permeable resin primer and topcoat can be permeated into the concrete matrix to form the anticorrosion layer of "matrix-coating", "mixing element integration", so that it not only has excellent acid corrosion resistance, but also has high and low temperature alternation and airflow scouring performance, solve the problem that chimney lining anticorrosion layer fails due to stress corrosion, also has good construction performance, solve the difficult problem that chimney lining anticorrosion layer construction period is short.

Description

Technical Field

[0001] This invention belongs to the technical field of anti-corrosion and waterproof materials, and relates to a nano-penetrating resin coating for construction in high humidity and water-bearing environments for the anti-corrosion of desulfurization chimney linings. Background Technology

[0002] Currently, my country's power structure is still dominated by thermal power generation, and the flue gas from coal combustion contains a large amount of dust, SO2, and NO. x Pollutants such as sulfur dioxide and sulfur dioxide pose serious threats to the environment and human health. Therefore, coal-fired power plants must perform desulfurization treatment on their flue gas. In my country, 80% of coal-fired power plants use wet limestone desulfurization technology. However, after wet desulfurization, the flue gas temperature decreases and humidity increases, causing condensation on the inner wall of the chimney and generating a highly corrosive dilute sulfuric acid solution. This causes strong corrosion to the chimney, necessitating anti-corrosion treatment of the chimney lining. Furthermore, the chimney operating environment is complex, with high flue gas flow and large temperature fluctuations, typically between 40 and 50°C, sometimes exceeding 180°C or even 200°C. This requires the anti-corrosion material of the desulfurization chimney lining to not only resist strong acid corrosion and temperature changes but also possess a certain degree of erosion resistance.

[0003] In my country, wet desulfurization technology in coal-fired power plants has been widely used for more than 20 years, and now a large number of old chimneys need to be renovated with anti-corrosion linings. The renovation faces practical problems: (1) The construction period is short. The entire anti-corrosion project usually takes about 45 days, which may lead to multiple trades working at the same time, posing safety hazards; (2) A large amount of acidic corrosive liquid remains on the inner wall of the old chimney, which cannot be drained in a short time. In most cases, the work needs to be carried out under high humidity and water conditions, which requires the anti-corrosion material of the desulfurization chimney lining to have good construction performance in high humidity environments.

[0004] Currently, domestic and international chimney lining corrosion protection basically involves creating a new corrosion protection layer on the base surface. Due to limitations in materials and construction, the corrosion protection layer and the base surface are only individually adhered and do not form an integrated whole. During use, bulging, cracking, and peeling may occur, leading to the loss of the corrosion protection function of the layer, a short service life of the layer, and even accidents caused by corrosion of the base material.

[0005] The invention patent CN102039702B discloses a steel-based mixed-element structure, composed of a steel substrate, a steel-based reducing agent, YD-01 polymer anti-corrosion coating, and a glaze toughening agent. The steel-based reducing agent, YD-01 polymer anti-corrosion coating, and glaze toughening agent penetrate into the pores of the steel substrate, reducing iron filings, rust, and other substances, forming a dense protective film on the steel substrate surface. This increases wear resistance and achieves good anti-corrosion and waterproofing effects, making it applicable to power plant chimneys, flues, and desulfurization absorption towers. However, this structure and anti-corrosion layer are only suitable for steel substrate structures. Due to its inherent drawbacks, the steel substrate structure has limited versatility, restricting its use and promotion.

[0006] The invention patent with announcement number CN101913810B discloses a concrete-based composite material, which consists of a concrete lining layer, a reducing agent, a reinforcing agent, a repairing agent, a toughening agent, and a glazing agent. The reducing agent, reinforcing agent, repairing agent, and toughening agent penetrate deep into the surface layer of the original concrete lining layer, forming the main body of the concrete base. The glazing agent is coated on the surface of the main body of the concrete base, forming a chemical molecular chain structure with impermeability, temperature resistance, acid resistance, wear resistance, tensile strength, and resistance to thermal shock. Even if the glazed protective reinforcing surface is damaged, the main body still has the above anti-corrosion effects. However, the anti-corrosion layer of this mixed-structure requires a multi-step process, and the component ratios of reducing agent, reinforcing agent, repair agent, toughening agent, and glazing agent vary depending on the concrete substrate. The construction requirements are high, and the adhesion between the various layers will change with the change of components. When the anti-corrosion layer of the mixed-structure is subjected to long-term high and low temperature alternation and airflow erosion, the coating's protective performance will fail due to stress corrosion. Furthermore, the main components of the reducing agent are epoxy resin and phenolic amine curing agent, which are highly polar and soluble in water, thus hindering the cross-linking curing reaction and making it unsuitable for high-humidity environments.

[0007] Therefore, in order to solve the above problems, this invention is proposed. Summary of the Invention

[0008] To address the aforementioned technical problems, this invention aims to provide a nano-penetrating resin coating for construction in high-humidity, water-bearing environments for desulfurization chimney lining corrosion protection. The nano-penetrating resin primer and topcoat can penetrate into the concrete substrate to form a "substrate-coating" integrated corrosion protection layer, giving it not only excellent acid corrosion resistance but also resistance to high and low temperature alternation and airflow erosion. This solves the problem of chimney lining corrosion protection layer failure due to stress corrosion and also has good construction performance, solving the difficulties of short construction period and difficult operation of chimney lining corrosion protection layer.

[0009] To achieve the above objectives, the technical solution adopted by the present invention is as follows:

[0010] A nano-penetrating resin coating for corrosion protection of desulfurization chimney linings in high-humidity, water-bearing environments is disclosed. The chimney lining comprises, from the inside out, a reducing agent layer, a reinforcing agent layer, a primer layer, and a topcoat layer. The reducing agent layer consists of a reducing agent at a concentration of 0.25–0.45 kg / m³. 2 The reinforcing agent layer is formed by applying it to the surface of the chimney lining substrate, wherein the reinforcing agent is applied at a ratio of 0.15–0.30 kg / m². 2 The primer layer is formed by applying it to the surface of the reducing agent layer, wherein the primer layer is composed of a nano-penetrating resin primer at a concentration of 0.6–0.8 kg / m³. 2 It is formed by applying it to the surface of the reinforcing agent layer; the topcoat layer is made of nano-penetrating resin topcoat at a ratio of 1.2 to 1.5 kg / m². 2 It is formed by applying it to the surface of the primer layer.

[0011] As a limitation of this invention:

[0012] (i) The reducing agent is composed of silicone-modified acrylic resin, solvent and curing agent, wherein the solvent is a C9 mixed solvent, the curing agent is nonylphenol-modified Mannich base, and the mass ratio of silicone-modified acrylic resin and curing agent is 4:1.

[0013] (ii) The reinforcing agent is composed of a compound resin, a solvent and a curing agent. The compound resin is a mixture of silicone-modified epoxy resin and silicone-modified acrylic resin. The silicone-modified epoxy resin has a viscosity of 8000-10000 and an epoxy equivalent of 100-120 g / mol. The solvent is liquid paraffin and the curing agent is nonylphenol-modified Mannich base. The mass ratio of the compound resin to the curing agent is 6:1.

[0014] (III) The nano-penetrating resin primer is a two-component coating, wherein component A is composed of silicone-modified acrylic resin, silicone-modified epoxy resin, and additive A in a mass ratio of 100:10-20:5-10; component B is composed of curing agent nonylphenol-modified Mannich base and additive B in a mass ratio of 1:0.1-0.3.

[0015] Components A and B are mixed at a mass ratio of 10:1 and stirred evenly at room temperature to obtain a nano-penetrating resin primer.

[0016] (iv) The nano-penetrating resin topcoat is a two-component coating. Component A is composed of silicone-modified acrylic resin, silicone-modified epoxy resin, nano-inorganic filler, and additive C in a mass ratio of 100:10-20:20-40:10-30. Component B is composed of nonylphenol-modified Mannich base curing agent and additive D in a mass ratio of 1:0.1-0.3.

[0017] The nano-inorganic filler is one of silica, silicon carbide, and titanium dioxide, with a particle size of 10-30 nm.

[0018] Components A and B are mixed at a mass ratio of 10:1 and stirred evenly at room temperature to obtain a nano-penetrating resin topcoat.

[0019] As a further limitation of the present invention:

[0020] (i) The additive A is formed by mixing emulsifier, dispersant, defoamer and diluent, wherein the emulsifier is nonylphenol polyoxyethylene ether OP-9 or OP-10, the dispersant is BYK-111, the defoamer is BYK-055 and the diluent is n-butanol, and the mass ratio of the emulsifier, dispersant and defoamer to the diluent is 1:1:1:2.

[0021] (ii) The additive B is formed by mixing a penetrant and a diluent in a mass ratio of 1:5 to 10, wherein the penetrant is sodium polymethacrylate or sodium dodecyl sulfate, and the diluent is formed by mixing n-butanol and N-methyl-2-pyrrolidone in a volume ratio of 1:1.

[0022] (III) The additive C is a mixture of coupling agent, emulsifier, dispersant, defoamer and diluent, wherein the coupling agent is silane coupling agent KH-550, the emulsifier is nonylphenol polyoxyethylene ether OP-9 or OP-10, the dispersant is BYK-111, the defoamer is BYK-055, and the diluent is n-butanol; the mass ratio of the coupling agent, emulsifier, dispersant, defoamer and diluent is 2:1:1:1:2.

[0023] (iv) The additive D is composed of a waterproofing agent and a diluent mixed in a mass ratio of 1:6, wherein the waterproofing agent is an organosilicon waterproofing agent and the diluent is a mixture of n-butanol and ethanol in a volume ratio of 1:1.

[0024] This invention also has a limitation: the nonylphenol-modified Mannich base is prepared according to the following process:

[0025] Nonylphenol and aliphatic polyamine are added to a reaction vessel equipped with a reflux condenser and a stirrer at room temperature and heated to dissolve. Then formaldehyde is added, with the molar ratio of polyamine, nonylphenol and formaldehyde being 1-2:1:1. The mixture is heated to 100°C and refluxed for 1-3 hours. The water is removed by vacuum distillation to obtain nonylphenol-modified Mannich base. The nonylphenol-modified Mannich base is a light yellow transparent liquid with a viscosity (mPa·s, 25°C) of 1110-1300 and an amine value of 290-340 mgKOH / g.

[0026] The preparation of the anti-corrosion layer for the wet desulfurization chimney lining of the present invention is carried out according to the following steps:

[0027] (1) Treatment of substrate surface: Use a high-pressure water gun or air gun to clean the floating dust and severely corroded powder layer on the substrate surface; for old chimneys, the old coating needs to be removed.

[0028] (2) Penetration of reducing agent and application of reinforcing agent: Under room temperature conditions, the reducing agent is applied to the substrate surface by spraying, brushing, or roller coating. After 12 hours, the reinforcing agent is applied to the surface of the reducing agent coating to further complete the penetration of the reducing agent into the substrate. The amount of reducing agent used is 0.25–0.45 kg / m³. 2 The dosage of the reinforcing agent is 0.15–0.30 kg / m². 2 .

[0029] (3) Primer application: Under room temperature conditions, apply the nano-penetrating resin primer to the substrate surface by spraying, brushing, or rolling, and allow it to dry to the touch. The dosage is 0.6–0.8 kg / m². 2 .

[0030] (4) Topcoat application: Apply the nano-penetrating resin topcoat to the primer surface by spraying, brushing, or rolling, and allow it to dry slightly. The dosage is 1.2–1.5 kg / m². 2 .

[0031] The above-mentioned technical solution of the present invention is a whole in which each step is closely related and mutually influential, and together they determine the performance and lifespan of the coating.

[0032] Compared with the prior art, the present invention has the following beneficial effects:

[0033] (1) Organosilicon modified acrylic resin not only has the characteristic of low viscosity, but also the viscosity is greatly reduced under the action of additives, which makes it have good wetting performance with concrete substrate. It can easily penetrate into the rough and concave surface of cracks in concrete substrate. Driven by capillary action, it gradually penetrates into the micro-cracks and fills the micro-cracks, completing the penetration effect and becoming a "substrate-coating" "integrated" structure. It can solve the problem of stress corrosion failure caused by blistering, cracking and peeling of chimney lining anti-corrosion layer.

[0034] (2) Organosilicon-modified epoxy resin and organosilicon-modified acrylic resin contain Si-O bonds, which not only give the coating good flexibility and overcome the high brittleness of epoxy resin coating, but also reduce the surface energy of the coating and increase hydrophobicity when used as topcoat, thus overcoming the disadvantage of poor water resistance of acrylic resin coating, making it difficult for flue gas to adhere when condensation occurs, thereby reducing the corrosion of the substrate by acid. On the other hand, organosilicon-modified epoxy resin contains epoxy groups and organosilicon-modified acrylic resin contains carboxyl groups, which overcomes the disadvantage of low reactivity of organosilicon resin, which can only form a film on the surface of concrete substrate and in the inner wall of pores and has shallow penetration.

[0035] (3) The topcoat coating, which uses the same basic raw materials as the primer, can be well integrated with the primer and will not delaminate during use. Furthermore, the addition of nano-inorganic fillers to the topcoat effectively reduces the surface tension of the coating and increases its hydrophobicity, making it difficult for condensation gas to adhere to the surface. On the other hand, the nano-inorganic fillers have high hardness and, as fillers, give the coating good resistance to gas erosion, thereby improving the anti-corrosion effect of the coating and further extending the service life of the coating.

[0036] (4) The molecular chains of organosilicon modified acrylic resin and organosilicon modified epoxy resin not only contain carboxyl groups and epoxy groups, but also have highly polar hydroxyl groups. They are not only easy to react chemically with curing agents, but also easy to react chemically and physically with active groups on the surface of concrete substrates, resulting in very high adhesion between the coating and the substrate. The molecules of nonylphenol modified Mannich base curing agent not only contain amino groups, but also hydrophobic groups such as C9 aliphatic chains and benzene rings. It belongs to hydrophobic amino curing agent, which increases the hydrophobic properties of the molecules and has excellent curing performance in wet interfaces and even in water.

[0037] This invention is applicable to the construction of internal anti-corrosion lining for desulfurization chimneys in high humidity and water-bearing environments to form an anti-corrosion lining layer for the chimney. Detailed Implementation

[0038] The following embodiments are merely some, not all, of the embodiments of the present invention. Therefore, the detailed descriptions of the embodiments provided below are not intended to limit the scope of the claimed invention, but merely to illustrate selected embodiments. All other embodiments obtained by those skilled in the art based on the embodiments of the present invention without inventive effort are within the scope of protection of the present invention.

[0039] In this invention, unless otherwise specified, all equipment and raw materials are commercially available or commonly used in the industry. The methods described in the following embodiments are conventional methods in the art, unless otherwise specified.

[0040] In the following examples, the silicone-modified acrylic resin is a polysiloxane-modified epoxy acrylic resin containing vinyl groups, wherein the silicone content is 10-12%, the acid value is 4.0-4.6 mgKOH / g, and the viscosity (Ford cup 4, 25°C) is 20-30 s. The silicone-modified epoxy resin has a viscosity (Ford cup 4, 25°C) of 15-30 s and an epoxy value of 0.01-0.03 mol / 100g.

[0041] The room temperature described in the following embodiments of the present invention is 25±2℃.

[0042] Example 1

[0043] This embodiment describes the preparation of a nano-penetrating resin coating for corrosion protection of desulfurization chimney linings in high-humidity, water-bearing environments. The specific process is as follows:

[0044] 1) Synthesis of Mannich base as a curing agent

[0045] Nonylphenol and diethylenetriamine were added to a reactor equipped with a reflux condenser and a stirrer at room temperature and heated to dissolve them. Then, a 37% formaldehyde solution was added, with a molar ratio of diethylenetriamine, nonylphenol, and formaldehyde of 1:1:1. The mixture was heated to 100°C and refluxed for 1 hour. The water was removed by vacuum distillation to obtain the nonylphenol-modified Mannich base. The viscosity (25°C) of the nonylphenol-modified Mannich base was 1050 mPa·s, and the amine value was 310 mg KOH / g.

[0046] 2) Preparation of reducing agent

[0047] The reducing agent consists of silicone-modified acrylic resin, solvent, and curing agent. The solvent is a C9 mixed solvent, and the curing agent is a nonylphenol-modified Mannich base. The mass ratio of silicone-modified acrylic resin to curing agent is 4:1.

[0048] 3) Preparation of reinforcing agents

[0049] The reinforcing agent consists of a compound resin, a solvent, and a curing agent. The compound resin is a mixture of silicone-modified epoxy resin and silicone-modified acrylic resin. The solvent is liquid paraffin, and the curing agent is nonylphenol-modified Mannich base. The mass ratio of the compound resin to the curing agent is 6:1.

[0050] 4) Preparation of nano-penetrating resin primer

[0051] The nano-penetrating resin primer is a two-component coating. Component A is composed of silicone-modified acrylic resin, silicone-modified epoxy resin, and additive A (nonylphenol polyoxyethylene ether OP-9, BYK-111, BYK-055 and n-butanol mixed in a mass ratio of 1:1:1:2) mixed in a mass ratio of 100:10:10. Component B is composed of nonylphenol-modified Mannich base, additive B {sodium polyacrylate, mixed solvent [n-butanol and N-methyl-2-pyrrolidone (v:v=1:1)] mixed in a mass ratio of 1:5} mixed in a mass ratio of 1:0.2.

[0052] Under room temperature conditions, components A and B are mixed and stirred evenly at a mass ratio of 10:1 to obtain a nano-penetrating resin primer.

[0053] 5) Preparation of nano-penetrating resin topcoat

[0054] The nano-penetrating resin topcoat is a two-component coating. At room temperature, component A is composed of silicone-modified acrylic resin, silicone-modified epoxy resin, nano-silica (particle size 10-30 nm), and additive C (KH-550, nonylphenol polyoxyethylene ether OP-10, BYK-111, BYK055, and n-butanol in a mass ratio of 2:1:1:1:2) mixed in a mass ratio of 100:10:30:15. Component B is composed of nonylphenol-modified Mannich base, additive D {silicone waterproofing agent, and mixed solvent [n-butanol and ethanol (v:v = 1:1)] mixed in a mass ratio of 1:6} mixed in a mass ratio of 1:0.2.

[0055] The construction process of the anti-corrosion coating for the inner lining of wet desulfurization chimneys is as follows:

[0056] During the coating application process, the paint for each anti-corrosion coating needs to be prepared in real time.

[0057] Using acid-resistant bricks used as the lining material for the desulfurization chimneys of the 2×630MW units of Guangdong Datang International Chaozhou Power Generation Co., Ltd. as the experimental substrate, the surface dust was first cleaned with a water gun. After the bricks were wetted, the reducing agent was sprayed at a rate of 0.25 kg / m² at room temperature. 2 A reducing agent layer is formed by coating the substrate surface; after 12 hours, the reinforcing agent is then applied by spraying at a rate of 0.2 kg / m². 2 The coating is applied to the surface of the reducing agent cured layer to further promote its penetration into the substrate and form a reinforcing layer; after 12 hours, the nano-penetrating resin primer is then sprayed at a rate of 0.7 kg / m² within 1 hour. 2 Spray the coating onto the surface of the reinforcing agent layer; after standing for 3-5 hours, apply the nano-penetrating resin topcoat by spraying at a rate of 1.2 kg / m² within 1 hour. 2 The coating is sprayed onto the surface of the primer and allowed to dry completely to form an anti-corrosion layer, whose performance is then tested.

[0058] Example 2

[0059] This embodiment describes the preparation of a nano-penetrating resin coating for corrosion protection of desulfurization chimney linings in high-humidity, water-bearing environments. The specific process is as follows:

[0060] 1) Synthesis of Mannich base as a curing agent

[0061] Nonylphenol and diethylenetriamine were added to a reactor equipped with a reflux condenser and a stirrer at room temperature and heated to dissolve them. Then, a 37% formaldehyde solution was added, with a molar ratio of diethylenetriamine, nonylphenol, and formaldehyde of 2:1:1. The mixture was heated to 100°C and refluxed for 3 hours. The water was removed by vacuum distillation to obtain the nonylphenol-modified Mannich base. The viscosity (25°C) of the nonylphenol-modified Mannich base was 1110 mPa·s, and the amine value was 320 mg KOH / g.

[0062] 2) Preparation of reducing agent

[0063] The reducing agent consists of silicone-modified acrylic resin, solvent, and curing agent. The solvent is a C9 mixed solvent, and the curing agent is a nonylphenol-modified Mannich base. The mass ratio of silicone-modified acrylic resin to curing agent is 4:1.

[0064] 3) Preparation of reinforcing agents

[0065] The reinforcing agent consists of a compound resin, a solvent, and a curing agent. The compound resin is a mixture of silicone-modified epoxy resin and silicone-modified acrylic resin. The solvent is liquid paraffin, and the curing agent is nonylphenol-modified Mannich base. The mass ratio of the compound resin to the curing agent is 6:1.

[0066] 4) Preparation of nano-penetrating resin primer

[0067] The nano-penetrating resin primer is a two-component coating. Component A is composed of silicone-modified acrylic resin, silicone-modified epoxy resin, and additive A (nonylphenol polyoxyethylene ether OP-10, BYK-111, BYK-055 and n-butanol mixed in a mass ratio of 1:1:1:2) mixed in a mass ratio of 100:15:5. Component B is composed of nonylphenol-modified Mannich base, additive B {sodium polyacrylate, mixed solvent [n-butanol and N-methyl-2-pyrrolidone (v:v=1:1)] mixed in a mass ratio of 1:5} mixed in a mass ratio of 1:0.1.

[0068] Under room temperature conditions, components A and B are mixed and stirred evenly at a mass ratio of 10:1 to obtain a nano-penetrating resin primer.

[0069] 5) Preparation of nano-penetrating resin topcoat

[0070] The nano-penetrating resin topcoat is a two-component coating. At room temperature, component A is composed of silicone-modified acrylic resin, silicone-modified epoxy resin, nano-silica (particle size 10-30 nm), and additive C (KH-550, nonylphenol polyoxyethylene ether OP-9, BYK-111, BYK055, and n-butanol in a mass ratio of 2:1:1:1:2) mixed in a mass ratio of 100:15:20:10. Component B is composed of nonylphenol-modified Mannich base, additive D {silicone waterproofing agent, and mixed solvent [n-butanol and ethanol (v:v = 1:1)] mixed in a mass ratio of 1:6} mixed in a mass ratio of 1:0.3.

[0071] Under room temperature conditions, components A and B are mixed and stirred evenly at a mass ratio of 10:1 to obtain a nano-penetrating resin topcoat.

[0072] The construction process of the anti-corrosion coating for the inner lining of wet desulfurization chimneys is as follows:

[0073] During the coating application process, the paint for each anti-corrosion coating needs to be prepared in real time.

[0074] Using acid-resistant bricks used as the lining material for the desulfurization chimneys of the 2×630MW units of Guangdong Datang International Chaozhou Power Generation Co., Ltd. as the experimental substrate, the surface dust was first cleaned with a water gun. After the bricks were wetted, the reducing agent was sprayed at a rate of 0.3 kg / m² at room temperature. 2 A reducing agent layer is formed by coating the substrate surface; after 12 hours, the reinforcing agent is then applied by spraying at a rate of 0.15 kg / m². 2 The coating is applied to the surface of the reducing agent cured layer to further promote its penetration into the substrate and form a reinforcing layer; after 12 hours, the nano-penetrating resin primer is then sprayed at a rate of 0.6 kg / m² within 1 hour. 2 Spray the coating onto the surface of the reinforcing agent layer; after standing for 3-5 hours, apply the nano-penetrating resin topcoat by spraying at a rate of 1.3 kg / m² within 1 hour. 2 The coating is sprayed onto the surface of the primer and allowed to dry completely to form an anti-corrosion layer, whose performance is then tested.

[0075] Example 3

[0076] This embodiment describes the preparation of a nano-penetrating resin coating for corrosion protection of desulfurization chimney linings in high-humidity, water-bearing environments. The specific process is as follows:

[0077] 1) Synthesis of Mannich base as a curing agent

[0078] Nonylphenol and diethylenetriamine were added to a reactor equipped with a reflux condenser and a stirrer at room temperature and heated to dissolve. Then, a 37% formaldehyde solution was added, with a molar ratio of diethylenetriamine, nonylphenol, and formaldehyde of 1.5:1:1. The mixture was heated to 100°C and refluxed for 3 hours. Water was removed by vacuum distillation to obtain the nonylphenol-modified Mannich base. The viscosity (25°C) of the nonylphenol-modified Mannich base was 1300 mPa·s, and the amine value was 290 mg KOH / g.

[0079] 2) Preparation of reducing agent

[0080] The reducing agent consists of silicone-modified acrylic resin, solvent, and curing agent. The solvent is a C9 mixed solvent, and the curing agent is a nonylphenol-modified Mannich base. The mass ratio of silicone-modified acrylic resin to curing agent is 4:1.

[0081] 3) Preparation of reinforcing agents

[0082] The reinforcing agent consists of a compound resin, a solvent, and a curing agent. The compound resin is a mixture of silicone-modified epoxy resin and silicone-modified acrylic resin. The solvent is liquid paraffin, and the curing agent is nonylphenol-modified Mannich base. The mass ratio of the compound resin to the curing agent is 6:1.

[0083] 4) Preparation of nano-penetrating resin primer

[0084] The nano-penetrating resin primer is a two-component coating. Component A is composed of silicone-modified acrylic resin, silicone-modified epoxy resin, and additive A (nonylphenol polyoxyethylene ether OP-10, BYK-111, BYK-055 and n-butanol mixed in a mass ratio of 1:1:1:2) mixed in a mass ratio of 100:20:8. Component B is composed of nonylphenol-modified Mannich base, additive B {sodium polyacrylate, mixed solvent [n-butanol and N-methyl-2-pyrrolidone (v:v=1:1)] mixed in a mass ratio of 1:5} mixed in a mass ratio of 1:0.3.

[0085] Under room temperature conditions, components A and B are mixed and stirred evenly at a mass ratio of 10:1 to obtain a nano-penetrating resin primer.

[0086] 5) Preparation of nano-penetrating resin topcoat

[0087] The nano-penetrating resin topcoat is a two-component coating. At room temperature, component A is composed of silicone-modified acrylic resin, silicone-modified epoxy resin, nano-silica (particle size 10-30 nm), and additive C (KH-550, nonylphenol polyoxyethylene ether OP-9, BYK-111, BYK055, and n-butanol in a mass ratio of 2:1:1:1:2) mixed in a mass ratio of 100:20:40:30. Component B is composed of nonylphenol-modified Mannich base, additive D {silicone waterproofing agent, and mixed solvent [n-butanol and ethanol (v:v = 1:1)] mixed in a mass ratio of 1:6} mixed in a mass ratio of 1:0.1.

[0088] The construction process of the anti-corrosion coating for the inner lining of wet desulfurization chimneys is as follows:

[0089] During the coating application process, the paint for each anti-corrosion coating needs to be prepared in real time.

[0090] Using acid-resistant bricks used as the lining material for the desulfurization chimneys of the 2×630MW units of Guangdong Datang International Chaozhou Power Generation Co., Ltd. as the experimental substrate, the surface dust was first cleaned with a water gun. After the bricks were wetted, the reducing agent was sprayed at a rate of 0.4 kg / m³ at room temperature. 2 A reducing agent layer is formed by coating the substrate surface; after 12 hours, the reinforcing agent is then applied by spraying at a rate of 0.3 kg / m². 2 The coating is applied to the surface of the reducing agent cured layer to further promote its penetration into the substrate and form a reinforcing layer; after 12 hours, the nano-penetrating resin primer is then sprayed at a rate of 0.8 kg / m² within 1 hour. 2 Spray the coating onto the surface of the reinforcing agent layer; after standing for 3-5 hours, apply the nano-penetrating resin topcoat by spraying at a rate of 1.5 kg / m² within 1 hour. 2 The coating is sprayed onto the surface of the primer and allowed to dry completely to form an anti-corrosion layer, whose performance is then tested.

[0091] Example 4

[0092] This embodiment describes the preparation of a nano-penetrating resin coating for corrosion protection of desulfurization chimney linings in high-humidity, water-bearing environments. The specific process is as follows:

[0093] 1) Synthesis of Mannich base as a curing agent

[0094] Nonylphenol and diethylenetriamine were added to a reactor equipped with a reflux condenser and a stirrer at room temperature and heated to dissolve them. Then, a 37% formaldehyde solution was added, with a molar ratio of diethylenetriamine, nonylphenol, and formaldehyde of 1.5:1:1. The mixture was heated to 100°C and refluxed for 3 hours. The water was removed by vacuum distillation to obtain the nonylphenol-modified Mannich base. The viscosity (25°C) of the nonylphenol-modified Mannich base was 1190 mPa·s, and the amine value was 340 mg KOH / g.

[0095] 2) Preparation of reducing agent

[0096] The reducing agent consists of silicone-modified acrylic resin, solvent, and curing agent. The solvent is a C9 mixed solvent, and the curing agent is a nonylphenol-modified Mannich base. The mass ratio of silicone-modified acrylic resin to curing agent is 4:1.

[0097] 3) Preparation of reinforcing agents

[0098] The reinforcing agent consists of a compound resin, a solvent, and a curing agent. The compound resin is a mixture of silicone-modified epoxy resin and silicone-modified acrylic resin. The solvent is liquid paraffin, and the curing agent is nonylphenol-modified Mannich base. The mass ratio of the compound resin to the curing agent is 6:1.

[0099] 4) Preparation of nano-penetrating resin primer

[0100] The nano-penetrating resin primer is a two-component coating. Component A is composed of silicone-modified acrylic resin, silicone-modified epoxy resin, and additive A (nonylphenol polyoxyethylene ether OP-10, BYK-111, BYK-055 and n-butanol mixed in a mass ratio of 1:1:1:2) mixed in a mass ratio of 100:15:7. Component B is composed of nonylphenol-modified Mannich base, additive B {sodium polyacrylate, mixed solvent [n-butanol and N-methyl-2-pyrrolidone (v:v=1:1)] mixed in a mass ratio of 1:5} mixed in a mass ratio of 1:0.3.

[0101] Under room temperature conditions, components A and B are mixed and stirred evenly at a mass ratio of 10:1 to obtain a nano-penetrating resin primer.

[0102] 5) Preparation of nano-penetrating resin topcoat

[0103] The nano-penetrating resin topcoat is a two-component coating. At room temperature, component A is composed of silicone-modified acrylic resin, silicone-modified epoxy resin, nano-silica (particle size 10-30 nm), and additive C (KH-550, nonylphenol polyoxyethylene ether OP-9, BYK-111, BYK055, and n-butanol in a mass ratio of 2:1:1:1:2) mixed in a mass ratio of 100:15:30:20. Component B is composed of nonylphenol-modified Mannich base, additive D {silicone waterproofing agent, and mixed solvent [n-butanol and ethanol (v:v = 1:1)] mixed in a mass ratio of 1:6} mixed in a mass ratio of 1:0.1.

[0104] The construction process of the anti-corrosion coating for the inner lining of wet desulfurization chimneys is as follows:

[0105] During the coating application process, the paint for each anti-corrosion coating needs to be prepared in real time.

[0106] Using acid-resistant bricks used as the lining material for the desulfurization chimneys of the 2×630MW units of Guangdong Datang International Chaozhou Power Generation Co., Ltd. as the experimental substrate, the surface dust was first cleaned with a water gun. After the bricks were wetted, the reducing agent was sprayed at a rate of 0.45 kg / m² at room temperature. 2 A reducing agent layer is formed by coating the substrate surface; after 12 hours, the reinforcing agent is then applied by spraying at a rate of 0.25 kg / m². 2 The coating is applied to the surface of the reducing agent cured layer to further promote its penetration into the substrate and form a reinforcing layer; after 12 hours, the nano-penetrating resin primer is then sprayed at a rate of 0.65 kg / m² within 1 hour. 2 Spray the coating onto the surface of the reinforcing agent layer; after standing for 3-5 hours, apply the nano-penetrating resin topcoat by spraying at a rate of 1.4 kg / m² within 1 hour. 2 The coating is sprayed onto the surface of the primer and allowed to dry completely to form an anti-corrosion layer, whose performance is then tested.

[0107] Comparative Example

[0108] The following Comparative Examples 1-4 respectively prepared nano-penetrating resin coatings for corrosion protection of desulfurization chimney linings in high-humidity, water-bearing environments. The preparation and construction processes were similar to those in Example 1, as detailed below:

[0109] Comparative Example 1

[0110] The difference between this comparative example and Example 1 is that epoxy resin E-51 (viscosity (mPa·s, 25℃) of 11000~14000, epoxy equivalent: 180~200g / mol) is used instead of silicone-modified acrylic resin.

[0111] Comparative Example 2

[0112] The difference between this comparative example and Example 1 is that silicone-modified epoxy resin (viscosity (Ford cup 4, 25°C) 15-30s, epoxy value: 0.01-0.03mol / 100g) is used instead of silicone-modified acrylic resin.

[0113] Comparative Example 3

[0114] The difference between this comparative example and Example 1 is that an epoxy-based acrylic resin (viscosity (Ford cup 4, 25°C) of 10-20 s, acid value: 4.5-5.3 mg KOH / g) is used instead of the silicone-modified acrylic resin.

[0115] Comparative Example 4

[0116] The chloride ion diffusion coefficient was tested using acid-resistant bricks used as the lining material for the desulfurization chimney of the 2×630MW unit of Guangdong Datang International Chaozhou Power Generation Co., Ltd. as a comparative example.

[0117] The anti-corrosion layers obtained in Examples 1-4 and Comparative Examples 1-4 were subjected to performance tests. The test items, test standards and experimental results are shown in Table 1.

[0118] Table 1. Performance test results of anti-corrosion coatings in Examples 1-4 and Comparative Examples 1-4

[0119]

[0120]

[0121]

[0122] As can be seen from Table 1, the nano-permeable resin layer prepared by the present invention has good anti-corrosion stability. In the process of preparing the anti-corrosion layer, the nano-permeable resin coating of the present invention can penetrate into the substrate by more than 10 mm, and the prepared coating has corrosion resistance, which is significantly higher than that of the control group. The main reasons are: 1) When epoxy resin, as a film-forming agent, undergoes a chemical reaction between epoxy groups and amino groups with the amino curing agent Mannich base, it has the disadvantages of fast curing rate, high coating hardness, and strong brittleness. Therefore, when used as a reducing agent or reinforcing agent, its permeability is relatively weak. When used as a main component of the topcoat, the hydrophobicity of the coating is weak, resulting in poor acid and salt spray resistance; 2) When silicone-modified epoxy resin, as a film-forming agent, undergoes a cross-linking reaction with the amino Mannich base, it can not only solve the disadvantages of high coating hardness and strong brittleness, but also improve the hydrophobicity of the topcoat. However, it has the disadvantages of insufficient coating hardness and strong thermoplasticity, resulting in poor high-temperature resistance; 3) When epoxy-based acrylic resin, as a film-forming agent, undergoes a chemical reaction between epoxy groups and amino groups with the amino curing agent, it has poor permeability on the one hand, and poor hydrophobicity of the topcoat coating on the other hand; 4) Organosilicon-modified acrylic resin is used as the main film-forming agent and organosilicon-modified epoxy resin as the auxiliary film-forming agent. The resin has relatively weak polarity and low hydrophilicity, and can react with the amino curing agent Mannich base in high humidity environments, even in water, to form a hydrophobic coating. On the other hand, organosilicon-modified acrylic resin contains highly polar hydroxyl and ester groups, which can easily react with the surface active functional groups of concrete substrates and penetrate into them. The silicon monomers of organosilicon-modified acrylic resin and organosilicon-modified epoxy resin retain a certain proportion of hydrolyzed alkoxy groups at their ends, which undergo hydrolysis reaction when in contact with water. This ensures that after the resin film is formed, there is a certain degree of cross-linking between molecules, so that the reducing agent layer and the reinforcing agent layer, the reinforcing agent layer and the primer layer, and the primer layer and the topcoat layer are all interpenetrating, forming a "mixed and integrated" anti-corrosion layer with the substrate.

[0123] Finally, it should be noted that the above descriptions are merely preferred embodiments of the present invention and are not intended to limit the present invention. Although the present invention has been described in detail with reference to the foregoing embodiments, those skilled in the art can still modify the technical solutions described in the foregoing embodiments or make equivalent substitutions for some of the technical features. Any modifications, equivalent substitutions, improvements, etc., made within the spirit and principles of the present invention should be included within the scope of protection of the claims of the present invention.

Claims

1. A nano-penetrating resin coating for corrosion protection of desulfurization chimney linings in high-humidity, water-bearing environments, characterized in that, The chimney lining comprises, from the inside out, a reducing agent layer, a reinforcing agent layer, a primer layer, and a topcoat layer; the reducing agent layer consists of a reducing agent at a concentration of 0.25 ~ 0.45 kg / m³. 2 The reinforcing agent layer is formed by applying it to the surface of the chimney lining substrate, wherein the reinforcing agent is applied at a ratio of 0.15 ~ 0.30 kg / m². 2 It is formed by applying a primer layer to the surface of the reducing agent layer, wherein the primer layer is composed of a nano-penetrating resin primer at a concentration of 0.6 ~ 0.8 kg / m 2 It is formed by applying it to the surface of the reinforcing agent layer; the topcoat layer is made of nano-penetrating resin topcoat at a ratio of 1.2~1.5 kg / m 2 It is formed by applying it to the surface of the primer layer; The reducing agent is composed of silicone-modified acrylic resin, solvent, and curing agent. The solvent is a C9 mixed solvent, and the curing agent is a nonylphenol-modified Mannich base. The mass ratio of silicone-modified acrylic resin to curing agent is 4:

1. The silicone-modified acrylic resin is a polysiloxane-modified epoxy acrylic resin containing vinyl groups, wherein the silicone content is 10-12%, the acid value is 4.0-4.6 mgKOH / g, and the viscosity at 25°C (French cup 4) is 20-30 s. The reinforcing agent is composed of a compound resin, a solvent, and a curing agent, wherein the compound resin is a mixture of silicone-modified epoxy resin and silicone-modified acrylic resin, and the mass ratio of the compound resin to the curing agent is 6:

1. The nano-penetrating resin primer is a two-component coating. Component A is composed of silicone-modified acrylic resin, silicone-modified epoxy resin, and additive A in a mass ratio of 100:10~20:5~10. Component B is composed of nonylphenol-modified Mannich base curing agent and additive B in a mass ratio of 1:0.1~0.

3. Components A and B are mixed and stirred evenly at room temperature in a mass ratio of 10:1 to obtain a nano-penetrating resin primer. The nano-penetrating resin topcoat is a two-component coating. Component A is composed of silicone-modified acrylic resin, silicone-modified epoxy resin, nano-inorganic filler, and additive C in a mass ratio of 100:10~20:20~40:10~30. Component B is composed of nonylphenol-modified Mannich base curing agent and additive D in a mass ratio of 1:0.1~0.

3. The nano-inorganic filler is one of silica, silicon carbide, and titanium dioxide, with a particle size of 10-30 nm. Components A and B are mixed and stirred evenly at room temperature in a mass ratio of 10:1 to obtain a nano-penetrating resin topcoat.

2. The nano-penetrating resin coating for corrosion protection of desulfurization chimney linings in high-humidity, water-bearing environments, as described in claim 1, is characterized in that... The additive A is formed by mixing an emulsifier, a dispersant, an antifoamer, and a diluent, wherein the emulsifier is nonylphenol polyoxyethylene ether OP-9 or OP-10, the dispersant is BYK-111, the antifoamer is BYK-055, and the diluent is n-butanol, and the mass ratio of the emulsifier, dispersant, antifoamer, and diluent is 1:1:1:

2.

3. The nano-penetrating resin coating for corrosion protection of desulfurization chimney linings in high-humidity, water-bearing environments, as described in claim 1, is characterized in that... The auxiliary agent B is formed by mixing a penetrant and a diluent in a mass ratio of 1:5, wherein the penetrant is sodium polymethacrylate or sodium dodecyl sulfate, and the diluent is formed by mixing n-butanol and N-methyl-2-pyrrolidone in a volume ratio of 1:

1.

4. The nano-penetrating resin coating for corrosion protection of desulfurization chimney linings in high-humidity, water-bearing environments, as described in claim 1, is characterized in that... The additive C is a mixture of coupling agent, emulsifier, dispersant, defoamer and diluent, wherein the coupling agent is silane coupling agent KH-550, the emulsifier is nonylphenol polyoxyethylene ether OP-9 or OP-10, the dispersant is BYK-111, the defoamer is BYK-055, and the diluent is n-butanol; the mass ratio of the coupling agent, emulsifier, dispersant, defoamer and diluent is 2 : 1 : 1 : 1 :

2.

5. The nano-penetrating resin coating for corrosion protection of desulfurization chimney linings in high-humidity, water-bearing environments, as described in claim 1, is characterized in that... The additive D is composed of a waterproofing agent and a diluent mixed in a mass ratio of 1:6, wherein the waterproofing agent is an organosilicon waterproofing agent, and the diluent is a mixture of n-butanol and ethanol in a volume ratio of 1:

1.

6. The nano-penetrating resin coating for corrosion protection of desulfurization chimney linings in high-humidity, water-bearing environments, as described in any one of claims 1 to 5, is characterized in that... The nonylphenol-modified Mannich base was prepared according to the following process: Nonylphenol and aliphatic polyamine are added to a reaction vessel equipped with a reflux condenser and a stirrer at room temperature and heated to dissolve. Then formaldehyde is added, with the molar ratio of polyamine, nonylphenol and formaldehyde being 1~2:1:

1. The mixture is heated to 100°C and refluxed for 1~3 hours. The water is removed by vacuum distillation to obtain nonylphenol-modified Mannich base.

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