Methods for sealing corrosion and leakage points in gas pipelines under pressure

Abstract

This invention provides a method for pressurized sealing of corrosion leaks in gas pipelines, comprising the following steps: S1: Leak point classification; S2: Cleaning the leak point with a cleaning agent and quickly drying it with a dust-free dry cloth; S3: Applying waterproof adhesive tape to the leak point to form a glass sealant layer to seal the leak point; S4: Applying and compacting a metal sealing filler to the leak point; S5: Filling the micro-gaps in the leak point after applying the metal sealing filler and applying an anti-corrosion coating; S6: Sealing and curing. This invention's sealing method has a high success rate, good long-term durability, convenient and safe construction, and the classified treatment, by clearly defining the leak point classification standards, upgrades the leak sealing process from "experience-based" to "standardized": construction personnel only need to confirm the leak point classification to directly select and implement the appropriate process, without relying on personal experience, significantly reducing the operational threshold and allowing the process to be quickly replicated and promoted among different construction teams and different plant areas.

Description

Technical Field

[0001] This invention relates to a method for sealing corrosion leaks in gas pipelines under pressure. Background Technology

[0002] Metallurgical enterprises are major consumers and transmitters of coal gas, with complex gas pipeline networks and long total lengths (e.g., the Egang coal gas pipeline has a total length of 40 kilometers). Moreover, most of these pipelines have been in operation for more than 15 years. This means that during long-term use, the coal gas pipelines are in a harsh operating environment with pressure, moisture, and multiple corrosive media. In addition, the characteristics of some types of coal gas are affected by the production process (e.g., converter gas and coke oven gas have high water content and many tar impurities). Combined with the effects of some components in the coal gas (such as corrosive components such as hydrogen sulfide and carbon monoxide), electrochemical corrosion and pitting corrosion will continuously occur on the metal matrix of the pipeline. This can easily cause pitting micropores, corrosion perforation, and other leakage problems on the inner and outer walls of the pipeline, becoming a major safety hazard for the operation of coal gas pipelines.

[0003] Currently, the conventional methods for treating corrosion and leakage points in gas pipelines mainly fall into two categories: pressurized sealing with sealing materials and reinforcement with metal clamps. In some cases, multiple sealing layers are used to improve the effect. However, these methods all have insurmountable technical defects when dealing with gas pipelines with high water content or tar content: 1. Existing gas pipeline sealing materials such as sealants and metal fillers are generally hydrophobic and lack specific designs to resist tar swelling and adhere to water. When applied to leakage points with high water content or tar content, the materials cannot effectively adhere to the wet surface of the pipeline and are easily washed away by water or tar flow at the leak point. Even if a temporary coating is applied, interlayer separation and material detachment will occur due to continuous water or tar penetration, resulting in a low success rate of sealing and often requiring multiple resealing, making it impossible to achieve effective sealing in one go; 2. Existing processes often use a crude combination of simple cleaning and single-material sealing, without targeted graded construction operations for different leakage point diameters, resulting in over-construction or inadequate sealing. Summary of the Invention

[0004] In view of this, the purpose of the present invention is to provide a method for pressurized sealing of corrosion and leakage points in gas pipelines.

[0005] This invention is achieved using the following scheme: a method for pressurized sealing of corrosion leaks in gas pipelines, comprising the following steps: Step S1: Leakage point classification: Classify the leakage points according to their aperture size; Step S2: Clean the leak point 2-3 times with cleaning agent, and quickly wipe the cleaned area dry with a lint-free dry cloth; Step S3: Apply quick-drying waterproof tape to the leak point to form a glass sealant layer to seal the leak point. Step S4: Apply and compact the metal sealant to the leak point to form a metal sealant layer; Step S5: Fill the micro-gaps in the leak points after applying the metal sealant and then apply anti-corrosion coating. Step S6: Sealing and curing, pressurized sealing completed.

[0006] Furthermore, in step S1, the classification method for leakage points is as follows: Class A: Pitting micropores: pore size ≤ 1 mm, with no obvious water flow or tar seepage; Class B: Small perforations: pore size is 1-5mm, with slow water flow or tar seepage, and no splashing; Class C: Medium perforation: The diameter of the hole is 5-15mm, with water flow or tar splashing, and the leakage is moderate.

[0007] Furthermore, in step S2, a cleaning agent needs to be prepared before cleaning the leak points. The cleaning agent has the following composition: degreaser: rust remover: coke remover = 3:2:1.

[0008] Furthermore, in step S3: For Class A pitting micropores: No water isolation is required; proceed directly to step S4. For Class B small perforations: Apply quick-drying waterproof sealant in layers around the leak point and within a 3cm radius using a special scraper, applying a total of 2 layers. When applying the quick-drying waterproof sealant, press the sealant layer lightly to remove air bubbles and ensure that the sealant layer adheres tightly to the pipe surface. For Class C perforations: Apply quick-drying waterproof sealant in layers around the leak point and within a 3cm radius using a special scraper, applying a total of 2 layers. Simultaneously, after applying the first layer of quick-drying waterproof sealant, quickly lay down fiberglass mesh and press lightly to ensure that the first layer of quick-drying waterproof sealant and fiberglass mesh are completely adhered without any lifting edges. When applying the quick-drying waterproof sealant, press the sealant layer lightly to remove air bubbles and ensure that the sealant layer is tightly adhered to the pipe surface. The first layer of quick-drying waterproof adhesive is a thin coating with a thickness of 0.5-1mm, and the second layer of quick-drying waterproof adhesive is a thick coating with a total thickness of 1.5-2mm.

[0009] Furthermore, the preparation method of the quick-drying waterproof adhesive is as follows: (1) Preparation of component A: Heat the modified polyurethane prepolymer to 60°C, add hydrophobic fumed silica and nano calcium carbonate, disperse at high speed for 30 minutes, cool to room temperature and then seal and store; (2) Preparation of component B: Mix the amine curing agent with the water-absorbing resin powder and coupling agent evenly, and stir until evenly dispersed; (3) Mixing: Mix components A and B at a weight ratio of 10:1, stir for 1–2 minutes until uniform, and immediately apply to the surface of the leakage point. Furthermore, the mass ratio of each component of the quick-drying waterproof adhesive A is: modified polyurethane prepolymer: hydrophobic fumed silica: nano calcium carbonate = 100: 5-10: 10-15; the mass ratio of each component of the quick-drying waterproof adhesive B is: amine curing agent: water-absorbing resin micro powder: coupling agent = 5-8: 3-5: 1-2.

[0010] Furthermore, in step S4: For Class A pitting micropores: use a small scraper to press ultrafine iron powder-based filler into the micropores, and repeatedly compact it 3-4 times until the micropores are completely filled, so that the filler forms a tight bond with the pipe matrix without gaps. For Class B small perforations and Class C medium perforations: Apply ultrafine iron powder-based filler to the surface of the waterproof adhesive layer and compact it repeatedly 3-4 times until the micropores are completely filled, so that the filler forms a tight bond with the waterproof adhesive layer and the pipe substrate without gaps.

[0011] Furthermore, in step S4: ultrafine iron powder-based filler is used for type A pitting micropores and type B small perforations, and steel fiber reinforced iron powder-based filler is used for type C medium perforations.

[0012] Furthermore, in step S5: a two-component fast-curing repair agent is used to fill the micro-gaps. During filling, the two-component fast-curing repair agent is applied to the metal filler layer to completely cover the filler layer.

[0013] Furthermore, in step S5: after the two-component fast-curing repair agent has initially cured, an online repair and anti-corrosion coating resistant to coal gas corrosion is applied to form an anti-corrosion coating layer, which is smoothly connected to the original substrate of the pipeline.

[0014] Compared with existing technologies, this invention has the following advantages: 1. High sealing success rate: The sealing success rate of leaks in water- or tar-containing gas pipelines under pressure is extremely high, solving the problems of conventional materials falling off when exposed to water and requiring multiple sealing operations; 2. Good long-term durability: It forms a four-layer protective structure combining "waterproof sealing, plugging, reinforcement, and corrosion prevention," which is resistant to gas corrosion, water, and tar. The normal service life of the repaired pipeline is long, representing a qualitative improvement over the original temporary sealing method (service life ≤ 6 months); 3. Convenient and safe construction: The entire process is carried out under pressure. The process is efficient, requiring no gas outage or clamping, and is suitable for complex working conditions such as high altitudes or confined spaces. A single person can complete the sealing of small leaks, reducing the operation time to ≤60 minutes and significantly lowering safety risks. 4. Graded treatment: By clearly defining the classification standards for leaks, the leak sealing process is upgraded from "experience-based" to "standardized": Construction personnel only need to confirm the leak level category to directly select and implement the appropriate process, without relying on personal experience, greatly reducing the operational threshold and allowing the process to be quickly replicated and promoted among different construction teams and different factory areas. Attached Figure Description

[0015] Figure 1 This is a flowchart of the present invention. Detailed Implementation

[0016] The present invention will be further described below with reference to the accompanying drawings and embodiments.

[0017] It should be noted that the following detailed descriptions are exemplary and intended to provide further explanation of this application. Unless otherwise specified, all technical and scientific terms used herein have the same meaning as commonly understood by one of ordinary skill in the art to which this application pertains.

[0018] It should be noted that the terminology used herein is for the purpose of describing particular embodiments only and is not intended to limit the exemplary embodiments according to this application. As used herein, the singular form is intended to include the plural form as well, unless the context clearly indicates otherwise. Furthermore, it should be understood that when the terms "comprising" and / or "including" are used in this specification, they indicate the presence of features, steps, operations, devices, components, and / or combinations thereof.

[0019] like Figure 1 As shown, a method for pressurized sealing of corrosion leaks in gas pipelines includes the following steps: Step S1: Leakage point classification: Classify the leakage points according to their aperture size; Step S2: Clean the leak point 2-3 times with cleaning agent, and quickly wipe the cleaned area dry with a lint-free dry cloth; Step S3: Apply quick-drying waterproof tape to the leak point to form a glass sealant layer to seal the leak point. Step S4: Apply and compact the metal sealant to the leak point to form a metal sealant layer; Step S5: Fill the micro-gaps in the leak points after applying the metal sealant and then apply anti-corrosion coating. Step S6: Sealing and curing, pressurized sealing completed.

[0020] Since steel plant gas pipelines are often located in complex conditions such as high altitudes and confined spaces, tiered treatment makes construction operations more targeted and simpler, significantly reducing the difficulty of operation in complex conditions. Furthermore, traditional gas pipeline leak sealing processes are mostly experience-based, with construction personnel selecting materials and processes based on personal experience, lacking standardized procedures. This results in inconsistent sealing effects for the same type of leak, making the process difficult to replicate and scale up. Therefore, in this embodiment, the tiered method for leak points in step S1 is as follows: Class A: Pitting micropores: pore size ≤ 1 mm, with no obvious water flow or tar seepage; Class B: Small perforations: pore size is 1-5mm, with slow water flow or tar seepage, and no splashing; Class C: Medium perforation: The diameter of the hole is 5-15mm, with water flow or tar splashing, and the leakage is moderate.

[0021] By clearly defining the classification standards for leak points, the leak sealing process is upgraded from "experience-based" to "standardized": construction personnel only need to confirm the category of the leak point to directly select and implement the appropriate process, without relying on personal experience, which greatly reduces the operation threshold and allows the process to be quickly replicated and promoted among different construction teams and different factory areas. Simultaneously, graded treatment is the core design basis of this pressurized leak sealing technology solution for high water content or tar content coal gas pipelines. Its essence is to solve the core pain points of traditional processes through precise, customized and standardized design, and achieve multiple goals of "technology adaptation, effect guarantee, construction efficiency and cost control". At the same time, it makes the entire technical solution form an organic whole, improves the practicality, operability and patent creativity of the process, and fully adapts to the operation and maintenance needs of metallurgical enterprises for safe, long-term and efficient operation of coal gas pipelines.

[0022] In this embodiment, in step S2, a cleaning agent needs to be prepared before cleaning the leak points. The cleaning agent has the following composition: degreasing agent: rust remover: coking agent = 3:2:1. Specifically, the degreasing agent is a compound of nonionic surfactant (fatty alcohol polyoxyethylene ether) and anionic surfactant, used to quickly remove oil stains and light oil components of coal gas from the pipe surface, reduce the adhesion between tar and metal surface, and improve the wettability of the cleaning agent to avoid liquid residue on the curved surface of the pipe. The rust remover is a compound of phosphoric acid and citric acid, used to gently remove floating rust and corrosion pitting layer from the pipe surface, only peeling off the loose rust layer without damaging the base metal of the pipe. The phosphoric acid reacts with the metal to form a slight phosphating film, providing activation points for subsequent bonding. The coking agent is a compound of sodium hydroxide and sodium pyrophosphate, with the addition of tar emulsifier, to emulsify and decompose the viscous tar deposits (core pollutants of coke oven gas) on the pipe surface, decomposing the stubborn tar deposits into an easily cleanable emulsion that flows away quickly with the cleaning waste liquid, leaving no tar residue.

[0023] In this embodiment, the surface of leak points in pipelines with high water content or tar content is generally covered with composite pollutants such as oil, rust, tar deposits, and condensate. These pollutants form an isolation layer between the pipeline substrate and the sealing material, preventing the hydrophobic sealing material from effectively adhering to the metal surface. This is the core reason for poor adhesion and easy material detachment. In step S2 of this embodiment, a combination of degreasing agent, rust remover, and tar remover is used as a cleaning agent, rather than a simple surface wiping process as in traditional processes. This facilitates the thorough removal of surface pollutants, eliminates the adhesive isolation layer from the source, and significantly improves the material's adhesion.

[0024] In this embodiment, in step S3: For Class A pitting micropores: Since the leak points are relatively small, no water isolation is required, and the process proceeds directly to step S4; For Class B small perforations: Apply quick-drying waterproof sealant in layers around the leak point and within a 3cm radius using a special scraper, applying a total of 2 layers. When applying the quick-drying waterproof sealant, press the sealant layer lightly to remove air bubbles and ensure that the sealant layer adheres tightly to the pipe surface. For Class C perforations: Apply quick-drying waterproof sealant in layers around the leak point and within a 3cm radius using a special scraper, applying a total of 2 layers. Simultaneously, after applying the first layer of quick-drying waterproof sealant, quickly lay down fiberglass mesh and press lightly to ensure that the first layer of quick-drying waterproof sealant and fiberglass mesh are completely adhered without any lifting edges. When applying the quick-drying waterproof sealant, press the sealant layer lightly to remove air bubbles and ensure that the sealant layer is tightly adhered to the pipe surface. More specifically: the first layer of quick-drying waterproof adhesive is a thin coating with a thickness of 0.5-1mm, and the second layer of quick-drying waterproof adhesive is a thick coating with a total thickness of 1.5-2mm.

[0025] More specifically: The preparation method of quick-drying waterproof adhesive is as follows: (1) Preparation of component A: Heat the modified polyurethane prepolymer to 60°C, add hydrophobic fumed silica and nano calcium carbonate, disperse at high speed for 30 minutes, cool to room temperature and then seal and store; (2) Preparation of component B: Mix the amine curing agent with the water-absorbing resin powder and coupling agent evenly, and stir until evenly dispersed; (3) Mixing: Mix components A and B at a weight ratio of 10:1, stir for 1–2 minutes until uniform, and immediately apply to the surface of the leakage point. Specifically, the mass ratio of each component of component A of quick-drying waterproof adhesive is: modified polyurethane prepolymer: hydrophobic fumed silica: nano calcium carbonate = 100: 5-10: 10-15; the mass ratio of each component of component B of quick-drying waterproof adhesive is: amine curing agent: water-absorbing resin powder: coupling agent = 5-8: 3-5: 1-2.

[0026] Amine curing agents such as DMP-30 can be used, water-absorbing resin micro powder such as sodium polyacrylate can be used, and coupling agents such as KH-550 can be used. Modified polyurethane prepolymers provide elasticity, toughness, and rapid curing capability; hydrophobic fumed silica enhances hydrophobicity and improves thixotropy; nano-calcium carbonate enhances filling capacity and regulates rheological properties; amine curing agents promote rapid curing and adapt to humid interfaces; water-absorbing resin micropowders absorb trace amounts of moisture at the interface to form a dry interface; coupling agents enhance interfacial adhesion to the metal matrix.

[0027] In this embodiment, the quick-drying properties of the adhesive layer are used to form a superimposed water-resistant elastic film. The elasticity and toughness of the glass adhesive create a temporary barrier to the water source at the leak point, keeping the leak point dry and directly blocking the seepage of water and tar. This transforms the leak point from a wet or splashed state to a dry and sealed state, providing a dry and stable construction base for subsequent metal filler sealing. At the same time, the quick-drying water-resistant adhesive is a non-flammable and non-explosive material. There is no release of volatile organic solvents or sparks during construction, and no harmful gases are released after curing. It fully meets the safety operation requirements for explosion-proof, poison-proof, and fire-proof operation of gas pipelines. It avoids the risk of explosion and poisoning caused by contact between some organic solvent-based sealing materials and gas. The construction process does not require open flames or heating, and the film can be formed quickly at room temperature. It is highly consistent with the principle of emergency repair of gas pipelines under pressure without interruption of gas supply, ensuring the safety of on-site operations from the perspective of construction materials.

[0028] In this embodiment, the quick-drying waterproof adhesive and the mesh fabric work together to form a composite waterproof layer of "glass adhesive-mesh fabric-glass adhesive", which greatly improves the sealing performance. In particular, the mesh fabric provides mechanical support, interlocking anchoring, and structural shaping elastic skeleton for the entire waterproof layer, dispersing the local erosion force at the leakage point to the entire waterproof layer area and avoiding stress concentration leading to film damage. At the same time, the metal wire reinforcement layer of the mesh fabric can improve the overall tensile strength of the waterproof layer, making it more suitable for large-diameter perforations such as Class C perforations. This fundamentally solves the problems of weak erosion resistance of pure adhesive layers, poor bonding with subsequent filler layers, and easy cracking and detachment.

[0029] Furthermore, quick-drying waterproof adhesives have the following characteristics:

[0030] Compared to single-component silicone sealant, it cures faster, has stronger adhesion, and is unaffected by humid environments. Its water-absorbing resin micro-powder design actively absorbs moisture from the interface, creating a locally dry environment and solving the "water-sensitive" problem of traditional materials. Hydrophobic filler modification enhances the material's inherent hydrophobicity, reducing the risk of water penetration. Coupling agent enhancement forms chemical bonds with the metal matrix, improving long-term adhesion. Thixotropic optimization makes it suitable for vertical and horizontal application, preventing dripping and running.

[0031] The specific comparison with existing technologies is as follows:

[0032] In this embodiment, in step S4: different filling methods and fillers are used for different levels and types of leakage points, specifically: For Class A pitting micropores: use a small scraper to press ultrafine iron powder-based filler into the micropores, and repeatedly compact it 3-4 times until the micropores are completely filled, so that the filler forms a tight bond with the pipe matrix without gaps. For Class B small perforations and Class C medium perforations: Apply ultra-fine iron powder-based filler to the surface of the waterproof adhesive layer and compact it repeatedly 3-4 times until the micropores are completely filled, so that the filler forms a tight bond with the waterproof adhesive layer and the pipe substrate without gaps. For Class A pitting micropores and Class B small perforations, ultrafine iron powder-based filler (particle size ≤ 500 mesh) is used, and for Class C medium perforations, steel fiber reinforced iron powder-based filler (steel fiber and ultrafine iron powder in synergy) is used. In this embodiment, the metal filler provides a temporary sealing effect for the waterproof layer, providing a dense and high-strength base for subsequent reinforcement and anti-corrosion layers, resisting media erosion and pipeline pressure fluctuations, and ensuring long-term sealing performance. The ultrafine iron powder-based filler (≤500 mesh) can fully fill the micropores of pipeline pitting corrosion, the gaps in the mesh of the mesh cloth, and the tiny gaps around the leak point. However, for Class C perforations, due to the characteristics of high-pressure splashing, large leakage channels, and strong media erosion, the performance of the ultrafine iron powder-based filler is beyond its capacity. Therefore, the iron powder-based filler is reinforced with steel fibers to improve the performance of pure iron powder-based filler in terms of high strength, erosion resistance, and crack resistance.

[0033] In this embodiment, the ultrafine iron powder-based filler uses ultrafine iron powder aggregate (60%-70%) as the main aggregate, which can fill the micropores and gaps in the mesh cloth of the leak point, form homogeneous adsorption with the metal pipe, and improve the sealing tightness. The bonding and curing agent is an existing epoxy resin combined with the curing agent, supplemented by an existing silane coupling agent to improve the bonding force between the iron powder and the epoxy resin and prevent the filler from delamination. The steel fiber reinforced iron powder-based filler replaces part of the main aggregate of the ultrafine iron powder-based filler with stainless steel fiber.

[0034] In this embodiment, in step S5: a two-component fast-curing repair agent is used to fill the micro-gaps. During filling, the two-component fast-curing repair agent is applied to the metal filler layer to completely cover the filler layer. The two-component fast-curing repair agent can be the existing TS518 repair agent, which is used to fill the tiny pores of the metal sealing filler layer and bond tightly with the filler layer to form a gapless sealing reinforcement layer. This prevents water, tar, or gas from seeping through the filler gaps and improves the mechanical strength of the sealing layer. Its high strength and good toughness after curing can enhance the pressure resistance and erosion resistance of the entire sealing structure, resist the continuous impact of the medium in the gas pipeline, and prevent the sealing layer from deforming and falling off. It is a reinforcement layer for the whole. At the same time, the TS518 repair agent coating layer can form a firm bond with the front metal filler layer and the rear online repair anti-corrosion layer, improving the sealing durability.

[0035] In this embodiment, in step S5: after the two-component fast-curing repair agent has initially cured, an online repair and anti-corrosion coating resistant to coal gas corrosion is applied to form an anti-corrosion coating layer. The anti-corrosion coating layer is smoothly connected to the original pipeline substrate. The online repair and anti-corrosion coating can be an existing general-purpose heavy-duty anti-corrosion online repair coating, which can be used as an outer long-term anti-corrosion layer after the gas pipeline is plugged, thereby improving the service life of the pipeline repair.

[0036] In this embodiment, in step S6, after all materials have been allowed to stand and cure for 60 minutes, a leak detection test is required at the leakage points.

[0037] Application example: Operating conditions: The leak point at the bottom of the converter gas pipeline has a diameter of 10mm, contains water, has a pressure of 0.08 MPa, and a temperature of 50℃.

[0038] Application: After cleaning, apply the sealant to the leak point, 2-3mm thick; a waterproof layer will form within 5 minutes, and the surface will dry; subsequently, apply a metal sealant and an anti-corrosion layer. Results: Successful sealing on the first attempt; no leaks observed for 6 months.

[0039] Unless otherwise stated, if any of the technical solutions disclosed in this invention specify a numerical range, then the disclosed numerical range is a preferred numerical range. Anyone skilled in the art should understand that the preferred numerical range is merely one among many feasible numerical values ​​that has a more obvious or representative technical effect. Because there are many numerical values, it is impossible to list them all. Therefore, this invention discloses only some numerical values ​​to illustrate the technical solutions of this invention. Furthermore, the numerical values ​​listed above should not constitute a limitation on the scope of protection of this invention.

[0040] If the terms "first" or "second" are used in this document to specify components, those skilled in the art should know that the use of "first" or "second" is merely for the purpose of distinguishing components in description, and unless otherwise stated, the above terms have no special meaning.

[0041] If this invention discloses or relates to mutually fixedly connected components or structural parts, then, unless otherwise stated, a fixed connection can be understood as: a detachable fixed connection (e.g., using bolts or screws), or a non-detachable fixed connection (e.g., riveting, welding). Of course, mutually fixed connections can also be replaced by an integral structure (e.g., manufactured in one piece using a casting process) (except where it is obviously impossible to use an integral molding process).

[0042] Furthermore, the orientations or positional relationships used in any of the technical solutions disclosed in this invention above to indicate positional relationships, such as "longitudinal," "lateral," "up," "down," "front," "back," "left," "right," "vertical," "horizontal," "top," "bottom," "inner," and "outer," are based on the orientations or positional relationships shown in the accompanying drawings and are only for the convenience of describing this patent. They are not intended to indicate or imply that the device or element referred to must have a specific orientation, or be constructed and operated in a specific orientation. Therefore, they should not be construed as limitations on this patent. In addition, unless otherwise stated, the terms used to indicate shape in any of the technical solutions disclosed in this invention above include shapes that are similar to, close to, or approximate with it.

[0043] Any component provided by this invention can be assembled from multiple individual components or can be a single component manufactured by a one-piece molding process.

[0044] Finally, it should be noted that the above embodiments are only used to illustrate the technical solutions of the present invention and not to limit them; although the present invention has been described in detail with reference to preferred embodiments, those skilled in the art should understand that modifications can still be made to the specific implementation of the present invention or equivalent substitutions can be made to some technical features without departing from the spirit of the technical solutions of the present invention, and all such modifications and substitutions should be covered within the scope of the technical solutions claimed in the present invention.

Claims

1. A method for pressurized sealing of corrosion leaks in gas pipelines, characterized in that: Includes the following steps: Step S1: Leakage point classification: Classify the leakage points according to their aperture size; Step S2: Clean the leak point 2-3 times with cleaning agent, and quickly wipe the cleaned area dry with a lint-free dry cloth; Step S3: Apply quick-drying waterproof tape to the leak point to form a glass sealant layer to seal the leak point. Step S4: Apply and compact the metal sealant to the leak point to form a metal sealant layer; Step S5: Fill the micro-gaps in the leak points after applying the metal sealant and then apply anti-corrosion coating. Step S6: Sealing and curing, pressurized sealing completed.

2. The method for pressurized sealing of corrosion and leakage points in gas pipelines according to claim 1, characterized in that: In step S1, the classification method for leakage points is as follows: Class A: Pitting micropores: pore size ≤ 1 mm, with no obvious water flow or tar seepage; Class B: Small perforations: pore size is 1-5mm, with slow water flow or tar seepage, and no splashing; Class C: Medium perforation: The diameter of the hole is 5-15mm, with water flow or tar splashing, and the leakage is moderate.

3. The method for pressurized sealing of corrosion and leakage points in gas pipelines according to claim 1, characterized in that: In step S2, a cleaning agent needs to be prepared before cleaning the leak points. The cleaning agent has the following composition: degreaser: rust remover: coke remover = 3:2:

1.

4. The method for pressurized sealing of corrosion and leakage points in gas pipelines according to claim 2, characterized in that: In step S3: For Class A pitting micropores: No water isolation is required; proceed directly to step S4. For Class B small perforations: Apply quick-drying waterproof sealant in layers around the leak point and within a 3cm radius using a special scraper, applying a total of 2 layers. When applying the quick-drying waterproof sealant, press the sealant layer lightly to remove air bubbles and ensure that the sealant layer adheres tightly to the pipe surface. For Class C perforations: Apply quick-drying waterproof sealant in layers around the leak point and within a 3cm radius using a special scraper, applying a total of 2 layers. Simultaneously, after applying the first layer of quick-drying waterproof sealant, quickly lay down fiberglass mesh and press lightly to ensure that the first layer of quick-drying waterproof sealant and fiberglass mesh are completely adhered without any lifting edges. When applying the quick-drying waterproof sealant, press the sealant layer lightly to remove air bubbles and ensure that the sealant layer is tightly adhered to the pipe surface. The first layer of quick-drying waterproof adhesive is a thin coating with a thickness of 0.5-1mm, and the second layer of quick-drying waterproof adhesive is a thick coating with a total thickness of 1.5-2mm.

5. The method for pressurized sealing of corrosion and leakage points in gas pipelines according to claim 4, characterized in that: The preparation method of quick-drying waterproof adhesive is as follows: (1) Preparation of component A: Heat the modified polyurethane prepolymer to 60°C, add hydrophobic fumed silica and nano calcium carbonate, disperse at high speed for 30 minutes, cool to room temperature and then seal and store; (2) Preparation of component B: Mix the amine curing agent with the water-absorbing resin powder and coupling agent evenly and stir until evenly dispersed; (3) Mixing: Mix components A and B at a weight ratio of 10:1, stir for 1–2 minutes until uniform, and immediately apply to the surface of the leakage point.

6. The method for pressurized sealing of corrosion and leakage points in gas pipelines according to claim 5, characterized in that: The mass ratio of each component in component A of the quick-drying waterproof adhesive is: modified polyurethane prepolymer: hydrophobic fumed silica: nano calcium carbonate = 100: 5-10: 10-15; the mass ratio of each component in component B of the quick-drying waterproof adhesive is: amine curing agent: water-absorbing resin micro powder: coupling agent = 5-8: 3-5: 1-2.

7. The method for pressurized sealing of corrosion and leakage points in gas pipelines according to claim 1, characterized in that: In step S4: For Class A pitting micropores: use a small scraper to press ultrafine iron powder-based filler into the micropores, and repeatedly compact it 3-4 times until the micropores are completely filled, so that the filler forms a tight bond with the pipe matrix without gaps. For Class B small perforations and Class C medium perforations: Apply ultrafine iron powder-based filler to the surface of the waterproof adhesive layer and compact it repeatedly 3-4 times until the micropores are completely filled, so that the filler forms a tight bond with the waterproof adhesive layer and the pipe substrate without gaps.

8. The method for pressurized sealing of corrosion and leakage points in gas pipelines according to claim 7, characterized in that: In step S4: ultrafine iron powder-based filler is used for pitting micropores of type A and small perforations of type B, and steel fiber reinforced iron powder-based filler is used for medium perforations of type C.

9. The method for pressurized sealing of corrosion and leakage points in gas pipelines according to claim 1, characterized in that: In step S5: a two-component fast-curing repair agent is used to fill the micro-gaps. During filling, the two-component fast-curing repair agent is applied to the metal filler layer to completely cover the filler layer.

10. The method for pressurized sealing of corrosion leaks in gas pipelines according to claim 9, characterized in that: In step S5: After the two-component fast-curing repair agent has initially cured, an online repair and anti-corrosion coating resistant to coal gas corrosion is applied to form an anti-corrosion coating layer, which is smoothly connected to the original pipeline substrate.

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