Pipeline anti-corrosion structure, construction method and application of pipeline anti-corrosion structure

Abstract

The invention provides a pipeline anti-corrosion structure, a construction method and application of the pipeline anti-corrosion structure, and relates to the field of pipeline anti-corrosion. Comprising a first coating, reinforcing ribs, a high-temperature-resistant coating, a ceramic coating and a nano polyethylene coating which are sequentially arranged, the first coating is connected with the inner wall of the pipeline, and the reinforcing ribs are connected with the first coating or the interior of the pipeline in a welded mode. The construction method comprises the following steps: S1, treating the base material; s2, welding reinforcing ribs; s3, coating a base layer; s4, coating a middle layer; and S5, surface layer coating. By reducing the infiltration capacity of chloride ions, improving the high temperature resistance of the anti-corrosion structure, reducing the friction coefficient of the surface of the anti-corrosion structure and the like, pipeline corrosion caused by the chloride ions, high temperature, high flow speed and acid media can be effectively prevented and controlled.

Description

Technical Field

[0001] The present invention relates to the field of pipeline anti-corrosion, and more specifically, to a pipeline anti-corrosion structure, a construction method thereof, and an application thereof. Background Art

[0002] The conveying medium of the steelmaking high converter gas pipeline mainly consists of CO, CO2, H2, and N2, and also contains a small amount of water vapor, sulfides (H2S, SO2), and dust particles. These media will form acidic solutions under specific conditions. Especially in the presence of condensed water, a large amount of chloride ions (Cl - ) will be generated, and the Cl - concentration can reach 100 - 500 ppm, accelerating pitting corrosion and crevice corrosion of the pipeline. The pipeline temperature of the steelmaking high converter gas pipeline is usually 100 - 300 °C, the pressure is (0.1 - 0.3 MPa), and the high-speed gas (15 - 30 m / s) carries dust particles, resulting in erosion-corrosion, especially at elbows and pipe diameter changes.

[0003] Due to the aggregation of pitting / crevice corrosion (Cl - enrichment area) at elbows and pipe diameter changes, the maintenance frequency at elbows and pipe diameter changes is high, and it needs to be replaced every 1 - 3 years. The replacement requires production suspension, resulting in relatively large losses. To reduce the replacement frequency and improve the corrosion resistance of the pipeline, on the one hand, the pipeline material can be replaced, such as using corrosion-resistant steel (such as 09CrCuSb / ND steel), high-end stainless steel (such as 316L stainless steel), etc., which can significantly improve the corrosion resistance of the pipeline and reduce the replacement frequency, but the cost is 4 - 8 times higher than that of carbon steel, and it cannot fundamentally solve the pitting and crevice corrosion caused by high Cl - concentration.

[0004] On the other hand, coating / liner is applied to the inner wall of the pipeline, such as epoxy resin, polyurethane, or ceramic coating, with a thickness of about 200 - 500 μm, which can improve the corrosion resistance of the pipeline. However, during the high-speed dust erosion process, the coating is prone to peeling (the service life is usually less than 2 years), and the coating construction still needs to be carried out with the entire line shut down. Summary of the Invention

[0005] The purpose of the present invention is to provide an anti-corrosion structure for pipelines, in which the first coating can fix the rust layer, prevent further rusting, and the high-temperature resistant layer, ceramic coating, and nano-polyethylene coating can improve the anti-permeability of the anti-corrosion structure, and through multiple protections, the anti-corrosion performance is improved.

[0006] Another purpose of the present invention is to provide a construction method for a pipeline anti-corrosion structure, which can be directly constructed inside a rusty pipeline, saving costs.

[0007] Another third object of the present invention is to provide an application of an anti-corrosion structure in the converter gas pipeline of a steelmaking blast furnace. By reducing the penetration ability of chloride ions, improving the high-temperature resistance of the anti-corrosion structure, and reducing the friction coefficient on the surface of the anti-corrosion structure, etc., it can effectively prevent and control the pipeline corrosion caused by chloride ions, high temperature, high flow rate, and acidic medium.

[0008] The present invention solves its technical problems by adopting the following technical solutions.

[0009] On the one hand, an embodiment of the present invention provides an anti-corrosion structure for a pipeline, including a first coating, a strengthening rib, a high-temperature coating, a ceramic coating, and a nano-polyethylene coating arranged in sequence. The first coating is connected to the inner wall of the pipeline, and the strengthening rib is welded to the first coating or the inside of the pipeline.

[0010] In some embodiments of the present invention, the material of the strengthening rib is carbon steel or stainless steel.

[0011] In some embodiments of the present invention, the material of the above high-temperature coating is modified nano-level polyphenylene sulfide.

[0012] Polyphenylene sulfide (PPS) is a high-performance thermoplastic polymer composed of alternating benzene rings and sulfur atoms, and has excellent heat resistance, chemical stability, and mechanical properties.

[0013] Its characteristics are as follows: Heat resistance: The long-term use temperature can reach above 200 °C, and it can withstand 260 °C in the short term. Chemical stability: Resistant to acids, alkalis, and organic solvents, suitable for corrosive environments. Mechanical properties: High rigidity, strength, and wear resistance. Electrical insulation: Good electrical insulation performance, suitable for electrical applications. Flame retardancy: It has flame retardancy itself and does not require the addition of flame retardants. Its structural formula is:

[0014]

[0015] Modified polyphenylene sulfide is based on polyphenylene sulfide, and its performance is improved by adding fillers, reinforcing agents, etc. to meet specific requirements. The modification methods are:

[0016] Reinforcement modification: Adding glass fibers, carbon fibers, etc. to improve mechanical properties.

[0017] Filling modification: Adding inorganic fillers such as talcum powder, mica, etc. to improve dimensional stability and heat resistance.

[0018] Blending modification: Blending with other polymers to improve toughness or impact resistance.

[0019] Functional modification: Adding conductive and heat-conductive fillers to endow special functions.

[0020] Modified properties, mechanical properties: After reinforcement, the strength and rigidity are significantly improved. Heat resistance: After filling modification, the heat resistance is further enhanced. Dimensional stability: After filling modification, the shrinkage rate is reduced and the dimensions are more stable. Functionality: After functional modification, it can have properties such as conductivity and heat conduction.

[0021] The modified polyphenylene sulfide used in the present invention can be glass fiber modified polyphenylene sulfide, carbon fiber reinforced modified polyphenylene sulfide, talc powder modified polyphenylene sulfide, molybdenum disulfide filled modified polyphenylene sulfide, polyphenylene sulfide modified by blending polytetrafluoroethylene (PTFE) or polyvinylidene fluoride (PVDF), perfluoroalkoxy (PFA) modified polyphenylene sulfide, and so on.

[0022] In some embodiments of the present invention, the raw materials of the ceramic coating are one or more of silicon fluoride modified resin, glass flakes, and graphene.

[0023] In some embodiments of the present invention, the raw material of the above-mentioned nano polyethylene coating is high density polyethylene, and its density is 0.95 g / cm 3 , also called PE100.

[0024] In some embodiments of the present invention, the thickness of the anti-corrosion structure is 7 - 9 mm.

[0025] In some embodiments of the present invention, the thickness of the first coating is 1 - 2 mm, the height of the strengthening ribs is 2.5 mm, the thickness of the high temperature resistant coating is 1.5 - 2 mm, the thickness of the ceramic coating is 2 - 3 mm, and the thickness of the nano polyethylene coating is 2 - 3 mm.

[0026] On the one hand, the embodiments of the present invention provide a construction method for a pipeline anti-corrosion structure, including the following steps:

[0027] S1 Substrate treatment: Coating a coating on the inner wall of the pipeline to cure and coat the rust layer to obtain the first coating;

[0028] S2 Welding strengthening ribs: Welding strengthening ribs on the surface of the first coating processed in step S1;

[0029] S3 Base layer coating: Coating a high temperature resistant slurry on the inner wall of the pipeline and the surface of the strengthening ribs to obtain a high temperature resistant coating;

[0030] S4 Intermediate layer coating: Coating a ceramic slurry on the surface of the high temperature coating to obtain a ceramic coating;

[0031] S5 Surface layer coating: Coating a nano polyethylene slurry on the surface of the ceramic coating to obtain a nano polyethylene coating.

[0032] In step S1, the coating applied to the inner wall of the pipeline can be Peterson PS material, which is a polymer silicate material. It is a new substance obtained by the cross-linking reaction of modified isocyanate and silicate solution. It combines the advantages of silicate's chemical resistance and strong stability, as well as the good mechanical properties of resin, and forms a dense protective layer. It can resist the corrosion of strong acids, strong alkalis, high salts and most chemicals for a long time. It is environmentally friendly, non-toxic, flame-retardant, does not require a primer, and can be brush-coated / roller-coated / sprayed on various substrates such as carbon steel, stainless steel, and concrete. The construction period is short, and it is widely applicable to the heavy anti-corrosion applications in ocean engineering, energy engineering, large industrial enterprises, transportation industry, and municipal facilities.

[0033] It can also be a conversion type rust-inhibiting paint. Its principle is to convert rust (Fe2O3, Fe3O4) into a stable passivation layer (such as iron phosphate, chelate) through a chemical conversion reaction. For example, iron phosphate conversion paint: contains phosphoric acid and reacts with rust to form a dense iron phosphate film. Tannic acid conversion paint: a natural plant extract that chelates rust to form a protective layer. Water-based epoxy rust-inhibiting paint: contains a rust converter and can be directly brushed on the rusty surface. Such paints have simple construction, are environmentally friendly, and are suitable for mild to moderate rust.

[0034] It can also be a nano-rust-removing material. Utilizing the permeability and reactivity of nano materials (such as nano-SiO2, TiO2, graphene), it decomposes the rust layer and forms a protective film. For example, nano-silane penetrant: penetrates into the interior of the rust layer to form a hydrophobic protective film. Graphene-modified anti-corrosion paint: enhances conductivity and corrosion resistance and is suitable for high-corrosion environments.

[0035] In the above steps, after each coating, it needs to be dried, generally for 2 - 4 hours. Due to the narrow internal space of the pipeline, the construction difficulty is relatively large. Appropriate coating processes and equipment need to be adopted. For large-diameter pipelines, manual brushing is used, and for small-diameter pipelines, spraying is used. On the other hand, according to the size of the pipeline diameter, the density of the reinforcing ribs is also different. The reinforcing rib framework is generally grid-shaped or strip-shaped, and can also be other irregular shapes. When it is grid-shaped, the size of the grid: 3×3mm - 15×15mm. The diameter of the grid steel bars: 0.5 - 2mm. The material is low-carbon steel wire or stainless steel.

[0036] Thirdly, the present invention provides an application of an anti-corrosion structure in the converter gas pipeline of a steelmaking blast furnace, which is used to prevent and control the pipeline corrosion caused by one or more of chloride ions, high temperature, high flow rate, and acidic media.

[0037] Compared with the prior art, the embodiments of the present invention at least have the following advantages or beneficial effects:

[0038] The pipeline anti-corrosion structure provided by the present invention has a first coating that is in direct contact with the inner part of the pipeline / rust layer. This coating can infiltrate, coat, and solidify the rust layer, transforming the rust layer from a loose and porous form into a dense and continuous form. As a result, the harmful and active rust layer becomes an inert and stable protective layer, solving the rusting problem from the inside, preventing further corrosion of the rust layer, and further preventing the detachment of the anti-corrosion structure. The polyethylene layer on the surface can reduce the friction coefficient, reduce the scouring force of high-speed fluid on the anti-corrosion structure, and extend the service life of the anti-corrosion structure.

[0039] The preparation method provided by the present invention first performs substrate treatment and coats the paint inside the rusty pipeline. After the paint is applied on the metal surface with actual rust, the paint has the characteristics of enveloping rust marks, high temperature resistance, wet operation, strong adhesion, flame retardant paint film, and high construction efficiency. This can prevent the occurrence of flash rust and reverse rust phenomena, and to the greatest extent prevent the internal "rotting" caused by unclean rust treatment, resulting in the detachment of the anti-corrosion layer. The inner wall of the rusty pipeline is directly treated by painting the paint. The construction is simple. Compared with traditional surface treatment methods such as sandblasting, shot peening, and acid treatment, not only is the construction simple, but the treated pipeline is more conducive to the subsequent coating construction.

[0040] Secondly, strengthen the tendons by welding, which can further enhance the connection strength between the paint and the inner wall of the pipeline, and enhance the connection strength between the anti-corrosion layer and the inside of the pipeline. Then coat the high-temperature resistant coating. The modified nano-level polyphenylene sulfide has strong binding force and high binding strength with the paint. Moreover, the coating formed by the modified nano-level polyphenylene sulfide can increase the heat resistance temperature to above 300 °C, and its tolerance to chloride ions (Cl - ), acids, alkalis, and organic solvents is enhanced.

[0041] The ceramic coating can enhance the anti-chloride ion (Cl - ) penetration ability of the overall anti-corrosion coating. The Cl - penetration rate is reduced by 90%, which can effectively prevent the corrosion of the inner wall of the pipe body. The surface of the nano-polyethylene coating is smooth and has a small friction coefficient, which can reduce the friction force between the high-speed fluid and the nano-polyethylene coating, reduce the scouring force intensity of the overall anti-corrosion coating under high-speed fluid, and slow down and prevent the detachment of the anti-corrosion coating.

[0042] Applying the anti-corrosion structure provided by the present invention to the converter gas pipeline of a steelmaking blast furnace can reduce the chloride ion penetration rate, avoid the corrosion of the inner wall of the pipeline by chloride ions. At the same time, the high-temperature resistant layer can improve the stability of the anti-corrosion structure. The polyethylene layer on the surface is relatively smooth, which can reduce the scouring of the high-speed fluid on the anti-corrosion structure and extend the service life of the anti-corrosion structure. Description of the Drawings

[0043] To more clearly illustrate the technical solutions of the embodiments of the present invention, the accompanying drawings required for the embodiments will be briefly introduced below. It should be understood that the following drawings only show some embodiments of the present invention and should not be regarded as limiting the scope. For those of ordinary skill in the art, without creative efforts, other related drawings can also be obtained based on these drawings.

[0044] Figure 1 It is a schematic flow chart of the construction of the anti-corrosion structure in the embodiment of the present invention;

[0045] Figure 2 It is a schematic cross-sectional view of the anti-corrosion structure in the embodiment of the present invention;

[0046] Icon: 1 - pipeline, 2 - first coating, 3 - strengthening ribs, 4 - high-temperature resistant coating, 5 - ceramic coating, 6 - nano-polyethylene coating. Specific embodiments

[0047] To make the objectives, technical solutions, and advantages of the embodiments of the present invention clearer, the technical solutions in the embodiments of the present invention will be clearly and completely described below. For those not specified in the embodiments, they are carried out according to conventional conditions or conditions recommended by the manufacturer. For reagents or instruments not specified by the manufacturer, they are all conventional products that can be obtained through commercial purchase.

[0048] It should be noted that, without conflict, the embodiments in the present invention and the features in the embodiments can be combined with each other. The present invention will be described in detail below with reference to specific embodiments.

[0049] The features and performance of the present invention will be further described in detail below in conjunction with the embodiments.

[0050] Embodiment 1

[0051] According to the following construction method, an anti-corrosion structure, that is, an anti-corrosion layer, is constructed inside the converter gas pipeline 1 of the steelmaking blast furnace. The specific construction method is as follows:

[0052] S1 Substrate treatment: Coat a coating on the inner wall of the pipeline 1 to cure and coat the rust layer to form the first coating 2, and the average thickness of the first coating 2 is 1 mm;

[0053] S2 Weld the strengthening ribs 3: Weld the strengthening ribs 3 on the surface of the first coating 2 after the treatment in step S1; the material of the reinforcing ribs is stainless steel and the thickness is 2.5 mm.

[0054] S3 Base coating: Mix the modified polyphenylene sulfide powder and the solvent evenly to obtain a slurry, coat the slurry on the inner wall of the pipeline 1 and the surface of the strengthening ribs 3, and bake at high temperature to form a high-temperature resistant coating 4, and the thickness of the high-temperature coating is controlled at 2 mm;

[0055] S4 intermediate layer coating: glass flakes and vinyl resin are fully mixed to obtain slurry, and the slurry is coated on the surface of the high temperature resistant coating 4 to obtain a ceramic coating 5;

[0056] S5 surface coating: high-density polyethylene (HDPE) is sprayed on the surface of the ceramic coating 5 to obtain a nano-polyethylene coating 6.

[0057] Example 2

[0058] According to the following construction method, an anti-corrosion structure, i.e., an anti-corrosion layer, is constructed inside the coking ammonium sulfate mother liquor (temperature less than 90° C.) conveying pipeline 1. The specific construction method is as follows:

[0059] S1 substrate treatment: coating the inner wall of the pipe 1 to solidify and cover the rust layer to form a first coating 2, the average thickness of the first coating 2 is 1 mm;

[0060] S2 welding reinforcing ribs 3: welding reinforcing ribs 3 on the surface of the first coating 2 treated in step S1; the reinforcing ribs are made of low-carbon steel wire with a thickness of 2 mm.

[0061] S3 base coating: ordinary polyphenylene sulfide is coated on the inner wall of the pipe 1 and the surface of the reinforcing rib 3 under high temperature conditions to form a high temperature resistant coating 4;

[0062] S4 intermediate layer coating: thermally coating the modified polyolefin material on the surface of the high temperature resistant coating 4 to obtain a dense coating;

[0063] S5 surface coating: The surface is sprayed with high-density polyethylene to repair and form a smooth, scale-free and anti-corrosion surface.

[0064] Example 3

[0065] According to the following construction method, an anti-corrosion structure, i.e., an anti-corrosion layer, is constructed inside the saturator gas outlet (temperature 180°C) pipeline 1. The specific construction method is as follows:

[0066] S1 substrate treatment: coating the inner wall of the pipe 1 to solidify and cover the rust layer to form a first coating 2, the average thickness of the first coating 2 is 1 mm;

[0067] S2 Welding reinforcing ribs 3: Welding reinforcing ribs 3 on the surface of the first coating 2 treated in step S1; the reinforcing ribs are made of low-carbon steel wire with a thickness of 2.5 mm.

[0068] S3 base coating: fully combine glass flakes with silicone fluorine resin, and the slurry is coated on the inner wall of the pipe 1 and the surface of the reinforcing ribs 3 to form a high temperature resistant coating 4;

[0069] S4 Intermediate layer coating: Spraying modified polyphenylene sulfide on the surface of the high-temperature resistant coating 4 to obtain a multi-component synergistic controlled non-metallic coating;

[0070] S5 Surface layer coating: Spraying high-density polyethylene and performing surface finishing to obtain a smooth and dense non-metallic protective layer.

[0071] Example 4

[0072] According to the following construction method, an anti-corrosion structure, namely an anti-corrosion layer, is constructed inside the limestone-gypsum desulfurization (temperature 80°C) pipeline 1. The specific construction method is as follows:

[0073] S1 Substrate treatment: Coating the inner wall of the pipeline 1 with a coating to cure and coat the rust layer, forming a first coating 2 with an average thickness of 1 mm;

[0074] S2 Welding reinforcement ribs 3: Welding reinforcement ribs 3 on the surface of the first coating 2 after the treatment in step S1; the material of the reinforcement ribs is low-carbon steel wire with a thickness of 2 mm.

[0075] S3 Base layer coating: Spraying modified polyolefin on the inner wall of the pipeline 1 and the surface of the reinforcement ribs 3 to form a high-temperature resistant coating 4;

[0076] S4 Surface layer coating: Performing smooth and clean treatment on the surface layer to obtain a multi-component synergistic controlled non-metallic protective layer.

[0077] Example 5

[0078] According to the following construction method, an anti-corrosion structure, namely an anti-corrosion layer, is constructed inside the high-temperature bromine-containing acetic acid pipeline 1 in PTA production. The specific construction method is as follows:

[0079] S1 Substrate treatment: Coating the inner wall of the pipeline 1 with a coating to cure and coat the rust layer, forming a first coating 2 with an average thickness of 1 mm;

[0080] S2 Welding reinforcement ribs 3: Welding reinforcement ribs 3 on the surface of the first coating 2 after the treatment in step S1; the material of the reinforcement ribs is stainless steel with a thickness of 2 mm.

[0081] S3 Base layer coating: Thermally spraying modified polyphenylene sulfide material on the inner wall of the pipeline 1 and the surface of the reinforcement ribs 3 to form a high-temperature resistant coating 4;

[0082] S4 Intermediate layer coating: Fully fusing glass flakes and silicone fluoride resin on the surface of the high-temperature resistant coating 4 to obtain a dense protective coating;

[0083] S5 Surface layer coating: Spraying modified nano-polytetrafluoroethylene on the coating surface to obtain a nano excellent high-temperature resistant protective layer.

[0084] Comparative Example 1

[0085] The difference from Example 1 is that in this comparative example, the first coating 2 is not provided, and the remaining steps are the same as those in Example 1.

[0086] Comparative Example 2

[0087] The difference from Example 1 is that in this comparative example, the strengthening tendons and bones 3 are not provided, and the remaining steps are the same as those in Example 1.

[0088] Comparative Example 3

[0089] The difference from Example 1 is that in this comparative example, the high-temperature resistant coating 4 is not provided, and the remaining steps are the same as those in Example 1.

[0090] Comparative Example 4

[0091] The difference from Example 1 is that in this comparative example, the ceramic coating 5 is not provided, and the remaining steps are the same as those in Example 1.

[0092] Experimental Example

[0093] The pipelines 1 of Examples 1-5 and Comparative Examples 1-4 were tested for the performance of the anti-corrosion layer, and the results are shown in Table 1.

[0094] Table 1 Performance of each anti-corrosion layer

[0095]

[0096] In summary, for the anti-corrosion structure of the pipeline 1 provided in the embodiments of the present invention, the first coating 2 in direct contact with the inner part / rust layer of the pipeline 1 can infiltrate, coat and solidify the rust layer, changing the rust layer from a loose and porous form to a dense and continuous form, so that the harmful active rust layer becomes an inert and stable protective layer, solving the rust problem from the inside to prevent further corrosion of the rust layer, and further preventing the peeling off of the anti-corrosion structure. The polyethylene layer on the surface can reduce the friction coefficient, reduce the scouring force of high-speed fluid on the anti-corrosion structure, and extend the service life of the anti-corrosion structure.

[0097] The embodiments described above are some, but not all, of the embodiments of the present invention. The detailed description of the embodiments of the present invention is not intended to limit the scope of the claimed invention, but merely represents selected embodiments of the present invention. All other embodiments obtained by those of ordinary skill in the art based on the embodiments of the present invention without creative efforts fall within the scope of protection of the present invention.

Claims

1. A pipeline anti-corrosion structure, characterized in that: The invention comprises sequentially arranging a first coating, reinforcing ribs, a high temperature resistant coating, a ceramic coating and a nano-polyethylene coating, wherein the first coating is connected to the inner wall of a pipeline, and the reinforcing ribs are welded to the first coating or the inside of the pipeline.

2. The anti-corrosion structure of the pipeline according to claim 1, characterized in that: The reinforcing ribs are made of carbon steel or stainless steel.

3. The anti-corrosion structure of the pipeline according to claim 1, characterized in that: The material of the high-temperature coating is modified nano-scale polyphenylene sulfide.

4. The anti-corrosion structure of a pipeline according to claim 1, characterized in that: The raw material of the ceramic coating is one or more of silicon-fluorine modified resin, glass flakes and graphene.

5. The anti-corrosion structure of a pipeline according to claim 1, characterized in that: The raw material of the nano polyethylene coating is high-density polyethylene.

6. The anti-corrosion structure of a pipeline according to claim 1, characterized in that: The thickness of the anti-corrosion structure is 7-9 mm.

7. The anti-corrosion structure of a pipeline according to claim 1, characterized in that: The thickness of the first coating is 1-2 mm, the height of the reinforcing ribs is 2.5 mm, the thickness of the high temperature resistant coating is 1.5-2 mm, the thickness of the ceramic coating is 2-3 mm, and the thickness of the nano polyethylene coating is 2-3 mm.

8. A construction method for the anti-corrosion structure of a pipeline according to any one of claims 1 to 7, characterized in that: The following steps are involved: S1 substrate treatment: coating the inner wall of the pipeline to solidify and cover the rust layer to obtain the first coating; S2 welding reinforcement ribs: welding reinforcement ribs on the surface treated in step S1; S3 base coating: coating the inner wall of the pipe and the surface of the reinforcing ribs with a high temperature resistant slurry to obtain the high temperature resistant coating; S4 intermediate layer coating: coating the surface of the high temperature coating with ceramic slurry to obtain the ceramic coating; S5 surface coating: coating the surface of the ceramic coating with nano-polyethylene slurry to obtain the nano-polyethylene coating.

9. Use of the anti-corrosion structure according to any one of claims 1 to 7 in a steelmaking blast furnace converter gas pipeline.

10. The use according to claim 7, characterized in that: Used to prevent and control pipeline corrosion caused by one or more of chloride ions, high temperature, high flow rate, and acidic media.

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