Pressure pipeline trenchless repair material, preparation method and repair process

Abstract

The invention discloses a non-excavation repair material for a pressure pipeline, a preparation method and a repair process of the non-excavation repair material for the pressure pipeline. Comprising the following raw materials in parts by weight: 45 to 55 parts of thermoplastic polyurethane elastomer, 22 to 28 parts of polyvinyl alcohol, 6 to 10 parts of bio-enzyme preparation, 6 to 10 parts of nano silicon dioxide, 1.5 to 2.5 parts of azodiisobutyronitrile and 1.2 to 1.8 parts of zinc stearate. The preparation method of the pressure pipeline trenchless repair material comprises the following preparation processes: S1, preparing the thermoplastic polyurethane elastomer; s2, preparing a polyvinyl alcohol solution. A pressure pipeline non-excavation repairing technology comprises the following steps that firstly, a pipeline is detected and evaluated; and 2, cleaning the pipeline. The structure integrity and durability of the repaired pipeline can be remarkably improved, the service life of the pipeline is prolonged, the maintenance cost and the replacement frequency are reduced, the method is suitable for repairing the pressure pipeline in the open air or severe environment, and long-term safe operation of a pipeline system is guaranteed.

Description

Technical Field

[0001] The present invention relates to the field of pipeline repair, and in particular to a trenchless repair material for a pressure pipeline, a preparation method and a repair process. Background Art

[0002] Traditional pressure pipeline repair methods primarily include excavation repair and welding repair. Excavation repair requires extensive excavation of the ground above the pipeline. This method not only has a long construction period and high costs, but also has a significant impact on the surrounding environment, such as damaging roads, disrupting traffic, and interfering with residents' lives. It is difficult to implement in urban areas or busy traffic areas. Welding repair requires higher standards for pipeline materials and construction processes. For some older pipelines or pipelines made of special materials, welding may cause new stress concentration problems, resulting in damage to other parts of the pipeline after repair. Welding operations on pipelines containing flammable and explosive media also pose a high safety risk.

[0003] To overcome the shortcomings of traditional repair methods, trenchless repair technology has emerged and has gradually become a research hotspot. Trenchless repair technology can repair pipelines with minimal or no ground damage. It offers advantages such as rapid construction, relatively low costs, and minimal environmental impact. Lining pipelines with repair materials is an important trenchless repair method.

[0004] Existing pipeline repair materials have many shortcomings. Although some traditional organic repair materials have certain adhesion and flexibility, their strength and wear resistance are poor, and they are easily damaged by long-term high-pressure fluid impact and pipeline deformation. Inorganic repair materials such as cement-based materials have high strength, but they are brittle and lack flexibility. They have difficulty adapting to the thermal expansion and contraction and uneven settlement of the pipeline, and are prone to cracks, leading to repair failure. Moreover, most existing repair materials do not have self-repair functions. Once tiny cracks or damage appear, they cannot repair themselves. In harsh pipeline operating environments, the damage will gradually expand, reducing the repair effect and the service life of the pipeline.

[0005] In addition, there are often impurities such as oil and dirt in the pipeline. These impurities will affect the bonding effect between the repair material and the inner wall of the pipeline, reducing the quality of the repair. At the same time, in the underground environment, the pipeline will also be affected by factors such as ultraviolet rays and oxidation, which will cause the repair material to age and its performance to deteriorate. Therefore, it is of great practical significance to develop a non-excavation repair material for pressure pipelines with good comprehensive performance, including high strength, high toughness, good adhesion, self-repair function, and the ability to resist the influence of complex environmental factors in the pipeline. The present invention aims to solve the problems in the above-mentioned prior art and provide an innovative non-excavation repair material, preparation method and repair process for pressure pipelines. Summary of the Invention

[0006] The purpose of the present invention is to solve the shortcomings of the prior art and to propose an air-controlled valve for a dental machine system.

[0007] In order to achieve the above object, the present invention adopts the following technical solutions:

[0008] A trenchless repair material for a pressure pipeline, comprising the following raw materials by weight:

[0009] 45-55 parts of thermoplastic polyurethane elastomer, 22-28 parts of polyvinyl alcohol, 6-10 parts of biological enzyme preparation, 6-10 parts of nano-silicon dioxide, 1.5-2.5 parts of azobisisobutyronitrile, 1.2-1.8 parts of zinc stearate, 0.6-1 part of ultraviolet absorber, 2-4 parts of hindered phenol antioxidant, 8-12 parts of aramid fiber, and 3-7 parts of epoxy resin repair agent microcapsules.

[0010] The above-mentioned method for preparing a trenchless repair material for a pressure pipeline includes the following preparation steps:

[0011] S1. Preparing a thermoplastic polyurethane elastomer, selecting thermoplastic polyurethane elastomer particles of model TPU-95A, placing them in a vacuum drying oven, and drying them at 55° C. for 3 hours with a vacuum degree set to -0.08 MPa. The dried thermoplastic polyurethane elastomer particles were sieved through an 80-mesh sieve;

[0012] S2. Prepare a polyvinyl alcohol solution by slowly adding polyvinyl alcohol powder to deionized water in a mass ratio of 1:9. Stir at 85° C. for 1.5 hours at a stirring speed of 300 rpm until the polyvinyl alcohol is completely dissolved to form a uniform polyvinyl alcohol solution for later use.

[0013] S3. Prepare a bioenzyme preparation by mixing lipase, protease, and amylase in a mass ratio of 2:1:1. Grind the solid lipase in a mortar into a fine powder with a particle size of less than 100 μm. If the protease is in block form, crush it into small particles and then grind it into a fine powder. If the amylase is crystalline, grind it into a powder, and then fully mix the three enzyme powders. If a liquid enzyme preparation is available, measure it according to the corresponding proportion, stir it at 200 rpm at room temperature for 10 minutes, and mix it evenly before use.

[0014] S4. Prepare nano-silica by placing nano-silica with a particle size of 20-50 nm in an ultrasonic dispersion device, adding ethanol as a dispersant, with a mass ratio of nano-silica to ethanol of 1:5, and ultrasonically treating for 45 minutes at an ultrasonic power of 500 W to uniformly disperse it and prevent agglomeration;

[0015] S5. Preparing aramid fiber: cutting the aramid fiber into 5 mm lengths, and then treating the fiber in a muffle furnace at 350° C. for 15 minutes at a heating rate of 10° C. / minute. The treated aramid fiber is cooled to room temperature under nitrogen protection to remove surface impurities and increase its surface activity.

[0016] S6, prepare zinc stearate, first dissolve stearic acid in a sodium hydroxide solution with a concentration of 2 mol / L, the mass ratio of stearic acid to sodium hydroxide solution is 1:3, and stir at 75 ° C until completely dissolved to form a sodium stearate solution, then slowly add zinc sulfate solution with a concentration of 1.5 mol / L to the sodium stearate solution, the volume ratio of zinc sulfate solution to sodium stearate solution is 1:1, maintain the temperature at 75 ° C, while constantly stirring, the reaction generates zinc stearate precipitate, after the reaction is completed, the precipitate is filtered, washed with deionized water 3 times to neutral, dried to constant weight at 110 ° C, and ground into a fine powder with a particle size of less than 200 microns for standby use;

[0017] S7. Purchase pure azobisisobutyronitrile reagent from the market and store it in a dry, dark environment at a temperature of 10-25°C and a relative humidity of less than 60%. Purchase benzotriazole ultraviolet absorbers from the market. Purchase hindered phenol antioxidants from the market. Keep them sealed and dry, at a temperature of 5-30°C, and avoid contact with oxidants, acids, bases, and other substances.

[0018] S8. Prepare epoxy resin repair agent microcapsules. Add urea and formaldehyde in a molar ratio of 1:1.8 to a three-necked flask. Add deionized water to make the urea concentration reach 3 mol / L. Adjust the pH to 8.5. Stir in a 65°C water bath for 40 minutes to obtain a urea-formaldehyde resin prepolymer solution. For the core material, mix E-51 epoxy resin and diethylenetriamine in a mass ratio of 100:10. Add the core material to an aqueous solution containing 3% Span-80. Use a high-speed emulsifier at 3000 rpm for 12 minutes to obtain a stable oil-in-water emulsion. Add the emulsion dropwise to the urea-formaldehyde resin prepolymer solution. Adjust the pH of the mixture to 3.5 with dilute hydrochloric acid. Stir at 55°C for 2.5 hours to polymerize the urea-formaldehyde resin into the microcapsule wall. After the reaction, cool to room temperature, wash with deionized water until neutral, and filter or centrifuge to obtain dry microcapsules for use.

[0019] S9, preliminary mixing and dispersion;

[0020] S10, microcapsule addition and final mixing.

[0021] Preferably, in step S1, the vacuum degree fluctuation range of the vacuum drying oven is controlled within ±0.005 MPa.

[0022] Preferably, in step S3, the mixed bio-enzyme preparation is sieved with a mesh size of 200 meshes.

[0023] Preferably, in step S4, the ultrasonic dispersion equipment adopts an intermittent ultrasonic mode, that is, ultrasonicating for 10 seconds, pausing for 5 seconds, and so on in a cycle.

[0024] Preferably, in step S5, during the treatment of the aramid fiber in the muffle furnace, the oxygen content of the atmosphere in the furnace is controlled to be below 5%.

[0025] Preferably, in step S8, when preparing the epoxy resin repair agent microcapsules, the three-necked flask is equipped with a condensation reflux device.

[0026] Preferably, in step S10, during the microcapsule addition and final mixing process, the inner wall of the mixing container is coated with a polytetrafluoroethylene coating.

[0027] A trenchless repair process for a pressure pipeline, using the above-mentioned trenchless repair material for a pressure pipeline, includes the following steps:

[0028] The first step is pipeline inspection and assessment. Use pipeline inspection equipment to inspect the inside of the pressure pipeline, record the pipeline damage and parameters, and determine the repair location and plan accordingly.

[0029] The second step is pipeline cleaning. According to the condition of pipeline dirt, chemical cleaning or high-pressure water jet cleaning can be selected to remove oil, solid impurities, etc. in the pipeline, so that the inner wall of the pipeline is clean for the attachment of repair materials.

[0030] The third step is to transport the repair materials. For pipes of different diameters, pressure injection or pumping combined with hose transportation is used to deliver the materials to the repair site.

[0031] The fourth step is curing and post-processing of the repair material. After the repair material is injected, it is left to cure at room temperature for 24-48 hours according to its curing characteristics. After curing, the repair effect is checked, local defects are trimmed or polished, and relevant information of the repair project is recorded and archived.

[0032] The present invention has the following beneficial effects:

[0033] 1. This invention optimizes and synergizes material properties by compounding multiple components, including thermoplastic polyurethane elastomer, polyvinyl alcohol, nanosilica, and aramid fiber, in specific proportions. The thermoplastic polyurethane elastomer provides excellent elasticity and wear resistance, polyvinyl alcohol enhances adhesion, nanosilica improves strength and heat resistance, and aramid fiber imparts excellent tensile and crack resistance. This synergistic effect enables the repair material to effectively adapt to the complex stress environments of pressure pipelines, such as high-pressure fluid impact and pipeline deformation, significantly improving the structural integrity and durability of the repaired pipeline, extending its service life, and reducing maintenance costs and replacement frequency.

[0034] 2. The present invention contains epoxy resin repair agent microcapsules. When tiny cracks appear in the pipeline repair material, the microcapsules rupture to release the repair agent, automatically repairing the damaged area, maintaining the sealing and structural stability of the pipeline, and reducing safety hazards caused by the accumulation of tiny damage. At the same time, the ultraviolet absorber and hindered phenol antioxidant can effectively resist ultraviolet radiation and oxidation, prevent material aging and degradation, and ensure the stable performance of the repair material during long-term use. It is particularly suitable for repairing pressure pipelines in open air or harsh environments, ensuring the long-term safe operation of the pipeline system;

[0035] 3. The addition of the bioenzyme preparation of the present invention has multiple functions. On the one hand, during the operation of the pipeline, it can decompose oil stains, protein-based dirt and polysaccharide impurities in the pipeline, play a role in cleaning the inner wall of the pipeline, reduce the risk of pipeline blockage, and maintain good pipeline transportation efficiency. On the other hand, the bioenzyme may produce a certain catalytic effect inside the material, promoting the stability of the material structure or the progress of certain reactions. At the same time, the entire repair material system has a lower environmental pollution risk during the production, use and disposal process compared with some traditional repair materials, which conforms to modern environmental protection concepts and sustainable development requirements, and has significant advantages in the application of pressure pipeline repair in the fields of energy, chemical industry, etc.

[0036] 4. The unique preparation method and corresponding repair process make it suitable for the repair of pressure pipelines with different diameters. During the material preparation process, the fine processing and mixing of raw materials in each step such as S1-S10 ensure the stability and uniformity of material quality. During the repair process, pipeline inspection and evaluation can accurately locate the damaged part and formulate targeted repair plans; pipeline cleaning effectively removes dirt and provides good conditions for material adhesion; pressure injection or pumping method combined with hose delivery can flexibly adapt to pipelines of different diameters, ensuring that the repair material is accurately delivered to the repair site; room temperature curing and post-processing are simple to operate, without the need for complex equipment and high temperature and high pressure environment, improving construction efficiency and reducing the impact of construction on the surrounding environment. It is suitable for various complex construction sites and working conditions. BRIEF DESCRIPTION OF THE DRAWINGS

[0037] Figure 1 This is a chart showing changes in stress test data for repair group 1, repair group 2, and control group within 180 days;

[0038] Figure 2 This is a graph showing the changes in flow recovery rates of repair group 1, repair group 2, and control group within 180 days;

[0039] Figure 3 This is a graph showing the absolute value of the lining thickness deviation changes in repair group 1, repair group 2, and control group within 180 days;

[0040] Figure 4 This is a graph showing changes in lining hardness in repair group 1, repair group 2, and control group within 180 days;

[0041] Figure 5 This is a graph showing the changes in bond strength of repair group 1, repair group 2, and control group within 180 days;

[0042] Figure 6 This is the change chart of corrosion weight loss rate of immersion test for repair group 1, repair group 2 and control group within 180 days;

[0043] Figure 7 This is a graph showing the change rate of corrosive substance content in the medium components of repair group 1, repair group 2 and control group within 180 days.

[0044] Figure 8 This is a picture of the pressure pipeline before repair material is filled.

[0045] Figure 9 A diagram of the pressure pipeline after it is filled with repair materials.

[0046] Figure 10 This is the cover image of the pressure pipeline inspection report after repair.

[0047] Figure 11 This is the result of the inspection report of the pressure pipeline after repair. DETAILED DESCRIPTION

[0048] The technical solutions in the embodiments of the present invention will be clearly and completely described below in conjunction with the drawings in the embodiments of the present invention. Obviously, the described embodiments are only part of the embodiments of the present invention, rather than all the embodiments.

[0049] A trenchless repair material for a pressure pipeline, comprising the following raw materials by weight:

[0050] 45-55 parts of thermoplastic polyurethane elastomer, 22-28 parts of polyvinyl alcohol, 6-10 parts of biological enzyme preparation, 6-10 parts of nano-silicon dioxide, 1.5-2.5 parts of azobisisobutyronitrile, 1.2-1.8 parts of zinc stearate, 0.6-1 part of ultraviolet absorber, 2-4 parts of hindered phenol antioxidant, 8-12 parts of aramid fiber, and 3-7 parts of epoxy resin repair agent microcapsules.

[0051] The above-mentioned method for preparing a trenchless repair material for a pressure pipeline includes the following preparation steps:

[0052] S1. Preparing a thermoplastic polyurethane elastomer, selecting thermoplastic polyurethane elastomer particles of model TPU-95A, placing them in a vacuum drying oven, and drying them at 55° C. for 3 hours. The vacuum degree of the vacuum drying oven is set to -0.08 MPa, and the vacuum degree fluctuation range of the vacuum drying oven is controlled within ±0.005 MPa. The dried thermoplastic polyurethane elastomer particles are sieved through an 80-mesh sieve;

[0053] S2. Prepare a polyvinyl alcohol solution by slowly adding polyvinyl alcohol powder to deionized water in a mass ratio of 1:9. Stir at 85° C. for 1.5 hours at a stirring speed of 300 rpm until the polyvinyl alcohol is completely dissolved to form a uniform polyvinyl alcohol solution for later use.

[0054] S3, prepare a bio-enzyme preparation, using lipase, protease and amylase in a mass ratio of 2:1:1 to mix, the solid lipase in a mortar into a fine powder with a particle size of less than 100 microns; if the protease is in block form, first crush it into small particles and then grind it into a fine powder; if the amylase is crystalline, grind it to a powder, and then fully mix the three enzyme powders; if there is a liquid enzyme preparation, after measuring it according to the corresponding proportion, stir it at a speed of 200 rpm at room temperature for 10 minutes to mix it evenly before use, and the mixed bio-enzyme preparation is sieved with a mesh size of 200 mesh;

[0055] S4, prepare nano-silica, place nano-silica with a particle size of 20-50nm in an ultrasonic dispersion device, add ethanol as a dispersant, the mass ratio of nano-silica to ethanol is 1:5, and ultrasonicate for 45 minutes at an ultrasonic power of 500W to uniformly disperse it and prevent agglomeration. The ultrasonic dispersion device adopts an intermittent ultrasonic mode, that is, ultrasonicate for 10 seconds, pause for 5 seconds, and so on.

[0056] S5. Preparing aramid fiber, cutting the aramid fiber into 5 mm lengths, and then treating the aramid fiber in a muffle furnace at 350° C. for 15 minutes at a heating rate of 10° C. / minute. During the treatment of the aramid fiber in the muffle furnace, the oxygen content of the furnace atmosphere is controlled to be below 5%. The treated aramid fiber is cooled to room temperature under nitrogen protection to remove surface impurities and increase its surface activity;

[0057] S6, prepare zinc stearate, first dissolve stearic acid in a sodium hydroxide solution with a concentration of 2 mol / L, the mass ratio of stearic acid to sodium hydroxide solution is 1:3, and stir at 75 ° C until completely dissolved to form a sodium stearate solution, then slowly add zinc sulfate solution with a concentration of 1.5 mol / L to the sodium stearate solution, the volume ratio of zinc sulfate solution to sodium stearate solution is 1:1, maintain the temperature at 75 ° C, while constantly stirring, the reaction generates zinc stearate precipitate, after the reaction is completed, the precipitate is filtered, washed with deionized water 3 times to neutral, dried to constant weight at 110 ° C, and ground into a fine powder with a particle size of less than 200 microns for standby use;

[0058] S7. Purchase pure azobisisobutyronitrile reagent from the market and store it in a dry, dark environment at a temperature of 10-25°C and a relative humidity of less than 60%. Purchase benzotriazole ultraviolet absorbers from the market. Purchase hindered phenol antioxidants from the market. Keep them sealed and dry, at a temperature of 5-30°C, and avoid contact with oxidants, acids, bases, and other substances.

[0059] S8. Prepare epoxy resin repair agent microcapsules. Add urea and formaldehyde in a molar ratio of 1:1.8 to a three-necked flask equipped with a condenser reflux device. Add deionized water to make the urea concentration reach 3 mol / L. Adjust the pH to 8.5 and stir in a 65°C water bath for 40 minutes to obtain a urea-formaldehyde resin prepolymer solution. For the core material, mix E-51 epoxy resin and diethylenetriamine in a mass ratio of 100:10. Add the core material to an aqueous solution containing 3% Span-80 and emulsify it with a high-speed emulsifier at 3000 rpm for 12 minutes to obtain a stable oil-in-water emulsion. Add the emulsion dropwise to the urea-formaldehyde resin prepolymer solution. Adjust the pH of the mixture to 3.5 with dilute hydrochloric acid and stir at 55°C for 2.5 hours to polymerize the urea-formaldehyde resin into the microcapsule wall. After the reaction, cool to room temperature, wash with deionized water until neutral, and filter or centrifuge to obtain dry microcapsules for use.

[0060] S9, preliminary mixing and dispersion, the pretreated thermoplastic polyurethane elastomer is added to a high-speed mixer, the speed is set to 1000 rev / min, and the initial mixing is stirred for 4 minutes, and the dispersed nano-silica is slowly added, and stirring is continued for 6 minutes to ensure uniform dispersion, and the prepared polyvinyl alcohol solution is added dropwise to the mixer, and the speed is reduced to 500 rev / min at the same time, and stirred for 9 minutes to fully mix it to form a viscous mixture, and the treated aramid fiber is added, and stirred for 6 minutes to make it evenly distributed, and bio-enzyme preparation, azobisisobutyronitrile, zinc stearate, ultraviolet absorber and hindered phenol antioxidant are added in sequence, and stirred at 400 rev / min for 4 minutes to ensure uniform mixing;

[0061] S10, adding microcapsules and final mixing, slowly adding the prepared epoxy resin repair agent microcapsules to the above mixture at a low speed (150 rpm), the inner wall of the mixing container is coated with a polytetrafluoroethylene coating, stirring for 4 minutes to prevent the microcapsules from breaking and making them evenly dispersed. After the mixing is completed, take out the material and place it at room temperature for 1.5 hours for preliminary maturation and stabilization to obtain a finished product of the pressure pipeline non-excavation repair material.

[0062] A trenchless repair process for a pressure pipeline, using the above-mentioned trenchless repair material for a pressure pipeline, includes the following steps:

[0063] The first step is pipeline inspection and assessment. Use pipeline inspection equipment to inspect the inside of the pressure pipeline, record the pipeline damage and parameters, and determine the repair location and plan accordingly.

[0064] The second step is pipeline cleaning. According to the condition of pipeline dirt, chemical cleaning or high-pressure water jet cleaning can be selected to remove oil, solid impurities, etc. in the pipeline, so that the inner wall of the pipeline is clean for the attachment of repair materials.

[0065] The third step is to transport the repair materials. For pipes of different diameters, pressure injection or pumping combined with hose transportation is used to deliver the materials to the repair site.

[0066] The fourth step is curing and post-processing of the repair material. After the repair material is injected, it is left to cure at room temperature for 24-48 hours according to its curing characteristics. After curing, the repair effect is checked, local defects are trimmed or polished, and relevant information of the repair project is recorded and archived.

[0067] Example 1:

[0068] Ten pressure pipes to be repaired and with similar damage levels were selected and designated as repair group 1. Repair group 1 used the repair material prepared by the above preparation method, namely: weighing 480g of thermoplastic polyurethane elastomer, 260g of polyvinyl alcohol, 70g of bioenzyme preparation, 80g of nano-silica, 22g of azobisisobutyronitrile, 15g of zinc stearate, 8g of ultraviolet absorber, 21g of hindered phenol antioxidant, 110g of aramid fiber, and 50g of epoxy resin repair agent microcapsules. The above repair process was used for repair. The pressure pipes in repair group 1 were in the following state before being filled with the repair material. Figure 8 As shown, the state after filling the repair material is as follows Figure 9 shown.

[0069] Within six months after the repair, the pressure pipes of repair group 1 were tested at 30 days, 60 days, 90 days, 120 days, 150 days and 180 days. The test items were: pressure test (relative pressure multiple before repair), flow recovery rate (%), lining thickness deviation (mm), lining hardness (Shore hardness), bonding strength (MPa), immersion test corrosion weight loss rate (%), medium component corrosive substance content change rate (%). The test data were recorded and the results are shown in the following table:

[0070] Table 1: Statistics of various test data of pressure pipes after repair in repair group 1

[0071]

[0072] Example 2:

[0073] Ten pressure pipes to be repaired, with damage similar to that in Example 1, were selected and designated Repair Group 2. The repair material prepared in Repair Group 2 was the same as in Example 1, with the same raw material ratios as in Example 1, except that the epoxy resin repair agent microcapsules were omitted. Specifically, the following ingredients were weighed: 480 g of thermoplastic polyurethane elastomer, 260 g of polyvinyl alcohol, 70 g of a bioenzyme preparation, 80 g of nanosilica, 22 g of azobisisobutyronitrile, 15 g of zinc stearate, 8 g of a UV absorber, 21 g of a hindered phenolic antioxidant, and 110 g of aramid fiber. The repair process was then used.

[0074] Within six months after the repair, the pressure pipes of repair group 2 were tested at 30 days, 60 days, 90 days, 120 days, 150 days and 180 days. The test items were: pressure test (relative pressure multiple before repair), flow recovery rate (%), lining thickness deviation (mm), lining hardness (Shore hardness), bonding strength (MPa), immersion test corrosion weight loss rate (%), and medium component corrosive substance content change rate (%). The test data were recorded and the results are shown in the following table:

[0075] Table 2: Statistics of various test data of pressure pipes after repair in repair group 2

[0076]

[0077] Example 3:

[0078] Ten pressure pipes to be repaired and with similar damage levels to those in Examples 1 and 2 were selected as a control group. These pressure pipes were repaired using conventional commercially available repair materials. It should be noted that the main components of the commercially available repair materials included resin, curing agent, and fiberglass cloth.

[0079] Within six months after the repair, the pressure pipes of the control group were tested at 30 days, 60 days, 90 days, 120 days, 150 days and 180 days. The test items were: pressure test (relative pressure multiple before repair), flow recovery rate (%), lining thickness deviation (mm), lining hardness (Shore hardness), bond strength (MPa), immersion test corrosion weight loss rate (%), medium component corrosive substance content change rate (%). The test data were recorded and the results are shown in the following table:

[0080] Table 3: Statistics of various test data of pressure pipes after repair in the control group

[0081]

[0082] Comprehensively compare the test data of Example 1, Example 2 and Example 3, and draw the same item data of the three examples into a line graph to obtain Figure 1-7 ,according to Figure 1-7 Analysis shows that:

[0083] like Figure 1 As shown in the pressure test, repair group 1 achieved an average maximum pressure bearing capacity of 1.19 times its pre-repair capacity throughout the entire monitoring period, with no leakage. This is due to the synergistic effect of the various components in the repair material: the thermoplastic polyurethane elastomer provides good elasticity and basic strength, the aramid fiber enhances tensile and crack resistance, the nano-silica improves overall strength and heat resistance, and the epoxy resin repair agent microcapsules can promptly perform self-repair when the material is subjected to pressure and may cause microscopic damage, preventing cracks from expanding, thereby ensuring the pipeline's high pressure bearing capacity and sealing performance.

[0084] Because repair group 2 lacked the epoxy resin microcapsules, its average maximum pressure bearing capacity was relatively low, only about 1.17 times the pre-repair level, and some pipes experienced minor leaks. This suggests that the self-healing function of the microcapsules is crucial for maintaining the integrity of the pipes under high pressure. Without this component, the material would be unable to self-heal even small cracks during long-term pressure exposure, resulting in reduced pressure bearing capacity and impaired sealing.

[0085] The control group, using conventional repair materials, had the worst pressure-bearing capacity, with an average maximum pressure-bearing capacity of only 1.16 times that of the pre-repair material, and also suffered from severe leakage. Conventional repair materials may lack strength, toughness, and self-healing capabilities, making them ineffective in coping with the high-pressure environment within the pipeline. This can lead to cracks and leaks, seriously compromising the safe operation of the pipeline.

[0086] Reference Figure 2 In flow testing, the flow recovery rate of repaired group 1 reached approximately 95%, close to the original pipeline flow level. This is because the repair material adheres well to the inner wall of the pipeline during the repair process, forming a uniform and smooth lining. The material's stability also ensures that it will not deform or fall off over time, minimizing the impact on the inner diameter and smoothness of the pipeline wall, ensuring excellent flow performance.

[0087] The flow recovery rate of repair group 2 was approximately 90%, slightly lower than that of repair group 1. Due to the lack of microcapsules, the internal structure of the material may have been unstable during curing or use, resulting in localized tiny cracks or unevenness, increasing fluid resistance and causing a decrease in flow rate.

[0088] The flow recovery rate in the control group was only around 82%, significantly lower than in the first two groups. Conventional repair materials may not be able to accurately repair damage to the inner wall of the pipe, resulting in a roughened inner wall and a reduced inner diameter after repair, which seriously hinders the smooth flow of fluid and causes significant flow loss.

[0089] like Figure 3、 Figure 4 and Figure 5 As shown, in terms of lining performance, first of all:

[0090] The maximum thickness deviation of the lining layer in repair group 1 was controlled within ±0.38mm, with excellent thickness uniformity. This is due to the precise weighing and mixing of the various components during the material preparation process, as well as specific preparation steps (such as drying and screening of the thermoplastic polyurethane elastomer and ultrasonic dispersion of nano-silica), which ensured material uniformity. This, in turn, resulted in a uniform and consistent thickness distribution of the lining layer after the pipeline repair, providing stable and reliable protection for the pipeline.

[0091] The maximum thickness deviation of the lining layer in repair group 2 was approximately ±0.4 mm, indicating slightly poor uniformity. The lack of epoxy resin microcapsules may have affected the microstructural formation of the material during the curing process, resulting in less precise thickness control than in repair group 1. However, this was still within an acceptable range, indicating that microcapsules have a certain positive impact on thickness uniformity, but are not the sole determining factor.

[0092] The control group showed significant deviation in liner thickness, with a maximum average deviation of ±0.43 mm. Conventional repair material preparation and construction techniques may lack effective means for precise thickness control, leading to uneven liner thickness. This not only affects the overall performance of the pipeline but can also create stress concentration points due to thickness variations, accelerating pipeline damage.

[0093] Secondly:

[0094] The lining hardness of repair group 1 ranges from 50 to 66 Shore A, an ideal value. This hardness effectively resists erosion and abrasion from the media within the pipeline while maintaining a good fit with the original pipe, avoiding stress concentration issues caused by excessive hardness. This is the result of the combined effects of multiple ingredients: nano-silica increases hardness, while thermoplastic polyurethane elastomer provides elastic cushioning, resulting in a moderate hardness and stable performance.

[0095] The hardness of repair group 2 ranged from 48 to 63 Shore A, which is relatively low. The lack of microcapsules may have slightly reduced the stability and density of the material's internal structure, affecting the increase in hardness and potentially posing some risks in long-term wear resistance. However, it still generally meets short-term requirements.

[0096] The hardness values ​​in the control group fluctuated significantly, ranging from 45 to 61 Shore A. Conventional repair materials suffer from unstable composition and processing, making it difficult to effectively control the uniformity and stability of hardness. This results in significant hardness variations across different areas, making it prone to wear in areas with lower hardness while leaving areas with higher hardness poorly bonded to the original pipe, impacting the repair effect and pipe life.

[0097] Furthermore:

[0098] The average bond strength of repair group 1 reached a maximum of 3.41 MPa, far exceeding the design requirement of 2.5 MPa. This indicates strong adhesion between the repair material and the original pipe. The adhesive properties of polyvinyl alcohol and the thorough mixing and synergistic effect of the various components during the material preparation process enable the lining layer to adhere firmly to the inner wall of the pipe. The epoxy resin repair agent microcapsules may also have enhanced the interfacial adhesion between the material and the pipe wall to a certain extent, further improving the bond strength and ensuring that the lining layer is not easily detached during long-term use.

[0099] Repair Group 2 had the highest average bond strength of 3.33 MPa. While this met basic requirements, it was lower than that of Repair Group 1. The lack of microcapsules may have resulted in a less-than-tight microstructure at the interface between the material and the pipe wall, affecting the bond strength. This poses a potential risk of liner shedding under extreme operating conditions or during long-term use.

[0100] The average bond strength of the control group was only 2.26 MPa, significantly lower than the first two groups. The poor bonding performance of conventional repair materials may be due to insufficient adhesion of their components to the pipe wall, or the inability to form a good bonding interface during construction, which can easily lead to separation of the lining layer from the original pipe, rendering the repair ineffective and exposing the pipeline to renewed risk of damage.

[0101] The corrosion resistance can be referred to Figure 6 and Figure 7 As shown, the first immersion test showed:

[0102] After 180 days of immersion, the average surface corrosion weight loss rate of the specimens in repair group 1 was only 0.11%, and the corrosion depth was extremely shallow. This is attributed to the hindered phenolic antioxidants and UV absorbers added to the repair material, which effectively resist oxidation and UV aging. Ingredients such as nanosilica enhance the material's structural stability, making it less susceptible to corrosion by corrosive media. Furthermore, the epoxy resin microcapsules release the repair agent to repair the damaged area when the material suffers minor corrosion damage, further slowing the corrosion process and demonstrating excellent corrosion resistance.

[0103] The corrosion weight loss rate of repaired Group 2 was approximately 0.13%, and the corrosion depth increased. Due to the lack of self-repairing microcapsules, the material was unable to self-repair after minor corrosion damage, resulting in a gradual increase in corrosion severity. This demonstrates that the self-repair function of the microcapsules is crucial for improving the material's corrosion resistance and, to a certain extent, extending its service life in corrosive environments.

[0104] The control group experienced a high corrosion weight loss rate of 0.15%, with significant corrosion depth. Conventional repair materials lack effective corrosion protection and self-repair mechanisms. They are susceptible to chemical reactions in corrosive solutions, destroying the material structure and leading to severe corrosion. This makes them unable to provide long-term, reliable protection for pipelines.

[0105] Secondly, the analysis of medium composition shows:

[0106] After six months of operation, the content of corrosive substances in the pipeline's transported media in repaired Group 1 remained virtually unchanged compared to pre-repair levels, increasing only 0.16%. Furthermore, no significant corrosion was observed on the pipeline's inner wall. This demonstrates that the repair material is not only inherently corrosion-resistant but also effectively prevents chemical reactions between the pipeline and the media, maintaining the normal properties of the media within the pipeline and ensuring stable operation of the pipeline system. This is due to the material's barrier effect against corrosive substances and its self-healing function, which promptly repairs any minor corrosion damage that may occur, preventing further corrosion and contamination of the media.

[0107] The content of corrosive substances in the medium of repaired Group 2 increased slightly, by approximately 0.3%, and the inner wall of the pipe showed slight corrosion. This indicates that during long-term operation, due to the lack of the self-repairing effect of the microcapsules, the repair material's ability to block corrosive substances gradually decreased, and the pipeline began to show some degree of corrosion. This may affect the safe operation of the pipeline and the quality of the transported medium, requiring enhanced monitoring and maintenance.

[0108] The content of corrosive substances in the control medium increased significantly, reaching over 0.37%, and the inner wall of the pipeline showed severe corrosion. Conventional repair materials were unable to effectively resist the corrosive effects of the medium. Over time, the corrosion intensified, not only damaging the pipeline structure but also allowing large amounts of corrosive substances to enter the medium, seriously affecting the normal operation of the pipeline system. The pipeline needed to be replaced or repaired promptly, increasing operating costs and safety risks.

[0109] In summary, the comparative test of Example 1 shows that the repair material containing specific weight component raw materials (45-55 parts thermoplastic polyurethane elastomer, 22-28 parts polyvinyl alcohol, 6-10 parts bioenzyme preparation, 6-10 parts nano-silica, 1.5-2.5 parts azobisisobutyronitrile, 1.2-1.8 parts zinc stearate, 1.2-1.8 parts zinc stearate, 0.6-1 parts ultraviolet absorber, 2-4 parts hindered phenol antioxidant, 8-12 parts aramid fiber, 3-7 parts epoxy resin repair agent microcapsules) and prepared according to a specific preparation method (S1-S10) has significant advantages in non-excavation repair of pressure pipelines. Compared with similar materials without epoxy resin repair agent microcapsules and conventional repair materials, it shows better performance in pipeline strength and sealing, lining performance, corrosion resistance, etc. This repair material can effectively improve the pressure-bearing capacity and flow recovery rate of the repaired pipeline, ensure the uniform thickness of the lining layer, moderate hardness, and high bonding strength, and at the same time has excellent corrosion resistance and self-repairing capabilities, significantly extending the service life of the pressure pipeline and improving the safety and reliability of pipeline operation. It provides an efficient and high-quality solution for the non-excavation repair of pressure pipelines, and has broad application prospects and important engineering value.

[0110] It should be added that the pressure pipelines repaired with this new repair material and corresponding process have been inspected and a test report has been issued, such as Figure 10 and Figure 11 As shown in the internal pressure resistance test (normal temperature, test pressure: 2.6MPa, 1h), the test results showed no damage and no leakage, and the test was qualified.

[0111] Therefore, in actual engineering applications, priority should be given to the use of this new repair material and corresponding technology for the repair of pressure pipelines to reduce maintenance costs, reduce safety hazards and improve the overall performance of the pipeline system.

[0112] The above description is only a preferred specific embodiment of the present invention, but the scope of protection of the present invention is not limited thereto. Any technician familiar with the technical field, within the technical scope disclosed by the present invention, who makes equivalent replacements or changes based on the technical solution and inventive concept of the present invention, should be covered by the scope of protection of the present invention.

Claims

1. A trenchless repair material for a pressure pipeline, characterized in that: Made of the following raw materials by weight: 45-55 parts of thermoplastic polyurethane elastomer, 22-28 parts of polyvinyl alcohol, 6-10 parts of biological enzyme preparation, 6-10 parts of nano-silicon dioxide, 1.5-2.5 parts of azobisisobutyronitrile, 1.2-1.8 parts of zinc stearate, 0.6-1 part of ultraviolet absorber, 2-4 parts of hindered phenol antioxidant, 8-12 parts of aramid fiber, and 3-7 parts of epoxy resin repair agent microcapsules.

2. The method for preparing a trenchless repair material for a pressure pipeline according to claim 1, wherein: The preparation process includes the following: S1. Preparing a thermoplastic polyurethane elastomer, selecting thermoplastic polyurethane elastomer particles of model TPU-95A, placing them in a vacuum drying oven, and drying them at 55° C. for 3 hours with a vacuum degree set to -0.08 MPa. The dried thermoplastic polyurethane elastomer particles were sieved through an 80-mesh sieve; S2. Prepare a polyvinyl alcohol solution by slowly adding polyvinyl alcohol powder to deionized water in a mass ratio of 1:

9. Stir at 85° C. for 1.5 hours at a stirring speed of 300 rpm until the polyvinyl alcohol is completely dissolved to form a uniform polyvinyl alcohol solution for later use. S3. Prepare a bioenzyme preparation by mixing lipase, protease, and amylase in a mass ratio of 2:1:

1. Grind the solid lipase in a mortar into a fine powder with a particle size of less than 100 μm. If the protease is in block form, crush it into small particles and then grind it into a fine powder. If the amylase is crystalline, grind it into a powder, and then fully mix the three enzyme powders. If a liquid enzyme preparation is available, measure it according to the corresponding proportion, stir it at 200 rpm at room temperature for 10 minutes, and mix it evenly before use. S4. Prepare nano-silica by placing nano-silica with a particle size of 20-50 nm in an ultrasonic dispersion device, adding ethanol as a dispersant, with a mass ratio of nano-silica to ethanol of 1:5, and ultrasonically treating for 45 minutes at an ultrasonic power of 500 W to uniformly disperse it and prevent agglomeration; S5. Preparing aramid fiber: cutting the aramid fiber into 5 mm lengths, and then treating the fiber in a muffle furnace at 350° C. for 15 minutes at a heating rate of 10° C. / minute. The treated aramid fiber is cooled to room temperature under nitrogen protection to remove surface impurities and increase its surface activity. S6, prepare zinc stearate, first dissolve stearic acid in a sodium hydroxide solution with a concentration of 2 mol / L, the mass ratio of stearic acid to sodium hydroxide solution is 1:3, and stir at 75 ° C until completely dissolved to form a sodium stearate solution, then slowly add zinc sulfate solution with a concentration of 1.5 mol / L to the sodium stearate solution, the volume ratio of zinc sulfate solution to sodium stearate solution is 1:1, maintain the temperature at 75 ° C, while constantly stirring, the reaction generates zinc stearate precipitate, after the reaction is completed, the precipitate is filtered, washed with deionized water 3 times to neutral, dried to constant weight at 110 ° C, and ground into a fine powder with a particle size of less than 200 microns for standby use; S7. Purchase pure azobisisobutyronitrile reagent from the market and store it in a dry, dark environment at a temperature of 10-25°C and a relative humidity of less than 60%. Purchase benzotriazole ultraviolet absorbers from the market. Purchase hindered phenol antioxidants from the market. Keep them sealed and dry, at a temperature of 5-30°C, and avoid contact with oxidants, acids, bases, and other substances. S8. Prepare epoxy resin repair agent microcapsules. Add urea and formaldehyde in a molar ratio of 1:1.8 to a three-necked flask. Add deionized water to make the urea concentration reach 3 mol / L. Adjust the pH to 8.

5. Stir in a 65°C water bath for 40 minutes to obtain a urea-formaldehyde resin prepolymer solution. For the core material, mix E-51 epoxy resin and diethylenetriamine in a mass ratio of 100:

10. Add the core material to an aqueous solution containing 3% Span-80. Use a high-speed emulsifier at 3000 rpm for 12 minutes to obtain a stable oil-in-water emulsion. Add the emulsion dropwise to the urea-formaldehyde resin prepolymer solution. Adjust the pH of the mixture to 3.5 with dilute hydrochloric acid. Stir at 55°C for 2.5 hours to polymerize the urea-formaldehyde resin into the microcapsule wall. After the reaction, cool to room temperature, wash with deionized water until neutral, and filter or centrifuge to obtain dry microcapsules for use. S9, preliminary mixing and dispersion; S10, microcapsule addition and final mixing.

3. The method for preparing a trenchless repair material for a pressure pipeline according to claim 2, characterized in that: In step S1, the vacuum degree fluctuation range of the vacuum drying oven is controlled within ±0.005 MPa.

4. The method for preparing a trenchless repair material for a pressure pipeline according to claim 2, characterized in that: In the step S3, the mixed bio-enzyme preparation is sieved with a sieve having a mesh size of 200 meshes.

5. The method for preparing a trenchless repair material for a pressure pipeline according to claim 2, characterized in that: In step S4, the ultrasonic dispersion device adopts an intermittent ultrasonic mode, that is, ultrasonication for 10 seconds, pause for 5 seconds, and so on.

6. The method for preparing a trenchless repair material for a pressure pipeline according to claim 2, characterized in that: In step S5, during the treatment of the aramid fiber in the muffle furnace, the oxygen content of the atmosphere in the furnace is controlled to be below 5%.

7. The method for preparing a trenchless repair material for a pressure pipeline according to claim 2, characterized in that: In the step S8, when preparing the epoxy resin repair agent microcapsules, the three-necked flask is equipped with a condensation reflux device.

8. The method for preparing a trenchless repair material for a pressure pipeline according to claim 2, characterized in that: In step S10, during the microcapsule addition and final mixing process, the inner wall of the mixing container is coated with a polytetrafluoroethylene coating.

9. A trenchless repair process for a pressure pipeline, using the trenchless repair material for a pressure pipeline according to claim 1 for repair, characterized in that: The process includes the following steps: The first step is pipeline inspection and assessment. Use pipeline inspection equipment to inspect the inside of the pressure pipeline, record the pipeline damage and parameters, and determine the repair location and plan accordingly. The second step is pipeline cleaning. According to the condition of pipeline dirt, chemical cleaning or high-pressure water jet cleaning can be selected to remove oil, solid impurities, etc. in the pipeline, so that the inner wall of the pipeline is clean for the attachment of repair materials. The third step is to transport the repair materials. For pipes of different diameters, pressure injection or pumping combined with hose transportation is used to deliver the materials to the repair site. The fourth step is curing and post-processing of the repair material. After the repair material is injected, it is left to cure at room temperature for 24-48 hours according to its curing characteristics. After curing, the repair effect is checked, local defects are trimmed or polished, and relevant information of the repair project is recorded and archived.

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