High-corrosion-resistance lining pipe material, preparation method thereof and oil and gas gathering and transportation pipeline

Abstract

The invention relates to the technical field of corrosion-resistant materials, and particularly discloses a high-corrosion-resistance lining pipe material, a preparation method thereof and an oil and gas gathering and transportation pipeline. The invention discloses a high-corrosion-resistance lining pipe material. The composite material is prepared from the following raw materials in parts by mass: 100 parts of high density polyethylene, 18 to 22 parts of high chlorinated polyethylene, 8 to 12 parts of polyvinylidene fluoride, 4 to 6 parts of zinc borate, 12 to 14 parts of modified phase change paraffin, 3 to 5 parts of core-shell structure graphene, 4 to 6 parts of ethylene-acrylic acid copolymer, 2 to 4 parts of diamino silane coupling agent, 0.3 to 0.5 part of tert-butyl peroxybenzoate and 0.3 to 0.5 part of trimethylolpropane trimethacrylate. 0.6 to 0.8 part of di-tert-butyl peroxide, 0.5 to 1 part of antioxidant and 0.3 to 0.5 part of anti-aging agent. The high-corrosion-resistance lining pipe material prepared in the invention has relatively good high-pressure corrosion resistance and mechanical properties under high pressure.

Description

Technical Field

[0001] The present application relates to the technical field of corrosion-resistant materials, and more specifically, to a highly corrosion-resistant lining pipe material and a preparation method thereof, and an oil and gas gathering and transportation pipeline. Background Art

[0002] In oil and gas field development, gathering and transportation pipelines are responsible for transporting crude oil, natural gas, and associated water containing acidic gases such as H2S and CO2. The wet corrosive environment they create can easily lead to corrosion, perforation, and leakage of the pipeline inner wall, threatening production safety and causing economic losses.

[0003] Currently, commonly used plastic-lined pipes, such as polyethylene, are low-cost and easy to construct, but they face significant challenges under the high-pressure conditions of oil and gas gathering and transportation. Acidic gases significantly increase their solubility and activity under high pressure, while ordinary plastics have long molecular chains and low crystallinity, allowing the medium to easily penetrate and accumulate within the lining, forming high-pressure bubbles that subsequently rupture. Furthermore, existing materials often focus on a single performance characteristic and lack systematic optimization. For example, simply adding fillers to increase hardness results in decreased toughness, making it difficult to withstand the impact of medium flow, exposing an imbalance between corrosion resistance, mechanical properties, and adaptability to operating conditions.

[0004] The patent application document with publication number CN118240292A discloses a corrosion-resistant polyethylene composite material, which includes the following components in parts by weight: 100 parts of polyethylene; 1 to 8 parts of a compatibilizer; 10 to 25 parts of an inorganic filler; and 5 to 12 parts of a corrosion-resistant modifier. The preparation method of the corrosion-resistant modifier includes the following steps: A1: stirring and mixing chitosan quaternary ammonium salt, silica and water, and drying to obtain silica coated with chitosan quaternary ammonium salt; A2: stirring and mixing silica coated with chitosan quaternary ammonium salt, a water-based epoxy resin, an aminosilane coupling agent and a solvent, and drying to obtain the corrosion-resistant modifier.

[0005] The core improvement in this solution lies in the introduction of silica coated with chitosan quaternary ammonium salt as a corrosion-resistant modifier, supplemented by an aminosilane coupling agent to enhance interfacial bonding. The thermal decomposition temperature of chitosan quaternary ammonium salt is typically 200-300°C, which partially overlaps with the polyethylene processing temperature (190-210°C). In the high-temperature environment of extrusion molding, chitosan quaternary ammonium salt is prone to degradation, resulting in damage to the silica coating. This not only partially ineffectively blocks the corrosion-resistant modifier from effectively blocking H2S and CO2 permeation, but also weakens its compatibility with the polyethylene matrix, further reducing the material's toughness. Summary of the Invention

[0006] In order to improve the corrosion resistance of the material, the present application provides a high-corrosion-resistant lining pipe material and a preparation method thereof, and an oil and gas gathering and transportation pipeline.

[0007] In the first aspect, the present application provides a highly corrosion-resistant liner pipe material, which adopts the following technical solution: A high corrosion-resistant lining pipe material is prepared by including the following raw materials in parts by weight: 100 parts of high-density polyethylene, 18-22 parts of highly chlorinated polyethylene, 8-12 parts of polyvinylidene fluoride, 4-6 parts of zinc borate, 12-14 parts of modified phase-change paraffin wax, 3-5 parts of core-shell graphene, 4-6 parts of ethylene-acrylic acid copolymer, 2-4 parts of bisaminosilane coupling agent, 0.3-0.5 parts of tert-butyl peroxybenzoate, 0.3-0.5 parts of trimethylolpropane trimethacrylate, 0.6-0.8 parts of di-tert-butyl peroxide, 0.5-1 parts of antioxidant, and 0.3-0.5 parts of antioxidant; The core-shell structure graphene has a composite core formed by graphene oxide and reduced graphene oxide as the core, and a polyimide coating layer loaded with metal ions as the shell; The modified phase-change paraffin wax is prepared by compounding normal paraffin wax and microcrystalline wax and grafting glycidyl methacrylate with an initiator.

[0008] In this scheme, high-density polyethylene (HDPE) serves as the continuous phase matrix and polyvinylidene fluoride (PVDF) as the dispersed phase, constructing a two-phase interpenetrating network. Through polarity adjustment of highly chlorinated polyethylene, this achieves a macroscale diffusion barrier to corrosive media. The graphene oxide sheets in the core-shell graphene form a physical shield, and the reduced graphene oxide constructs a conductive network. This synergistic zinc passivation film, generated by the hydrolysis of zinc borate, inhibits electrochemical corrosion of the metal substrate at the nanoscale when subsequently applied within the metal substrate, significantly improving the chemical corrosion resistance and aging resistance of the lining material itself. A bisaminosilane coupling agent strengthens the covalent bonding between the filler and the matrix, enhancing overall structural compatibility. A modified phase-change paraffin wax fills microcracks through temperature-responsive phase transition behavior, and combined with a peroxide-induced three-dimensional crosslinked network, it achieves in-situ crack repair and matrix structural reinforcement. From macroscopic phase protection to nanostructural reinforcement, and then to functional defect repair and long-term performance stabilization, the various components form a multi-level synergistic mechanism, forming a multi-scale corrosion resistance and durability improvement system, significantly enhancing the material's service reliability in high-pressure corrosive environments.

[0009] Preferably, the antioxidants include antioxidant 1010 and antioxidant 168.

[0010] Preferably, the bisaminosilane coupling agent is selected from any one of N-(2-aminoethyl)-3-aminopropyltrimethoxysilane and N-(2-aminoethyl)-3-aminopropyltriethoxysilane.

[0011] Preferably, the antioxidant is a hindered amine light stabilizer.

[0012] Preferably, the preparation method of the modified phase-change paraffin wax comprises the following steps: Under an inert atmosphere, add normal paraffin wax and microcrystalline wax into a reactor, heat to 75-110°C, mix evenly, add glycidyl methacrylate and part of the initiator, heat to 120-130°C, react for 50-70 minutes, then add the remaining initiator, heat to 130-140°C, react for 80-100 minutes, cool, wash, purify, and granulate to obtain the product.

[0013] Preferably, the mass ratio of the normal paraffin wax, microcrystalline wax and glycidyl methacrylate is (70-80): (20-30): (5-10).

[0014] Preferably, the initiator is benzoyl peroxide.

[0015] Preferably, the amount of benzoyl peroxide used is 1% to 1.5% of the total mass of normal paraffin wax and microcrystalline wax.

[0016] Preferably, the normal paraffin wax is a straight-chain alkane with a carbon chain length of C20-C28, a melting point of 65-70°C, and a phase change latent heat of ≥210 J / g.

[0017] Preferably, the microcrystalline wax has a carbon chain length of C30-C40, contains branched and cycloalkane structures, and has a melting point of 80-90°C.

[0018] In this scheme, the modified phase-change paraffin wax is based on normal paraffin wax, and epoxy groups are introduced by grafting glycidyl methacrylate. It is dispersed in the amorphous region of high-density polyethylene in a semi-crystalline state at room temperature. Its polar epoxy groups form partial dipole-dipole effects with the groups of polyvinylidene fluoride, enhancing the interfacial bonding between the two phases and inhibiting the diffusion of gas molecules in the amorphous region. When the material is impacted and microcracks are generated, local stress concentration causes the temperature rise in the microregion to trigger the paraffin phase change (from solid to semi-molten state). The low-viscosity wax liquid penetrates into the crack gap through the hydrogen bonding between the epoxy groups and the active components of the crack interface, and then cools and solidifies to form a physical repair structure, blocking the corrosion medium from extending along the crack path.

[0019] Preferably, the method for preparing the core-shell graphene comprises the following steps: (1) Graphene oxide, reduced graphene oxide, and a dispersant are uniformly dispersed in N-methylpyrrolidone, and polyamic acid prepared from 4,4′-diaminodiphenyl ether and pyromellitic dianhydride is added and mixed uniformly. After reacting at 25-30°C for 3-5 hours, acetic anhydride and 4-dimethylaminopyridine are added and the reaction is continued for 4-6 hours. The solid-liquid separation and washing are performed to obtain a composite. (2) The complex is dispersed in an ethanol aqueous solution, and after adding metal salt and citric acid, the pH is adjusted to 3-5, the temperature is raised to 40-60°C, the reaction is carried out for 8-10 hours, and the solid-liquid separation is performed, the washing is performed, and the drying is performed to obtain the product.

[0020] Preferably, the preparation method of the polyamic acid comprises the following steps: After mixing 4,4′-diaminodiphenyl ether and N-methylpyrrolidone evenly, cool to 0-5°C under an inert atmosphere, add pyromellitic dianhydride and mix evenly, and react for 2-4 hours to obtain the product; The molar ratio of the pyromellitic dianhydride to 4,4'-diaminodiphenyl ether is (1.05-1.1):1.

[0021] Preferably, the mass ratio of the graphene oxide to the reduced graphene oxide is (0.5-1.5):1.

[0022] Preferably, the dispersant is polyvinyl pyrrolidone, and the amount of polyvinyl pyrrolidone used is 1% to 1.5% of the total mass of graphene oxide and reduced graphene oxide.

[0023] Preferably, the amount of 4,4′-diaminodiphenyl ether used is (0.8-1.2) times the total mass of graphene oxide and reduced graphene oxide.

[0024] Preferably, the molar ratio of the 4,4′-diaminodiphenyl ether, acetic anhydride, 4-dimethylaminopyridine, metal salt and citric acid is 1:(1.8-2.2):(0.02-0.04):(0.2-0.5):(0.2-0.6).

[0025] Preferably, the metal salt is selected from at least one of zinc nitrate and copper nitrate.

[0026] In this scheme, graphene oxide adsorbs corrosive ions and reduces graphene oxide to evenly disperse conductive pathways to avoid the formation of metal substrate micro-batteries. At the same time, the outer amide groups coordinate with metal ions to form active centers, combined with the physical barrier effect, to inhibit the electrochemical corrosion of the metal substrate and the chemical corrosion of the polymer matrix.

[0027] Preferably, the high corrosion-resistant lining pipe material further includes 1.5 to 2 parts by mass of sodium molybdate.

[0028] In this scheme, sodium molybdate reacts with H2S in acidic media to form a dense layer of insoluble molybdenum sulfide. Simultaneously, when reacting with CO2, it forms a molybdenum-containing carbonate interphase layer through electrostatic adsorption, filling micropores and inhibiting gas permeation. The coordination synergy between sodium molybdate and the zinc ions in the core-shell graphene enhances the adsorption stability of H2S / CO2, further inhibiting acidic media from corroding the material.

[0029] Preferably, the high corrosion-resistant lining pipe material further comprises 2.5 to 3.5 parts by mass of ethylene-octene copolymer and 0.5 to 0.8 parts by mass of maleic anhydride grafted POE.

[0030] In a second aspect, the present application provides a method for preparing the above-mentioned inner lining pipe material, comprising the following steps: S1: Ethylene-acrylic acid copolymer and modified phase change paraffin are mixed uniformly at 85-125°C, extruded, cooled, and granulated to obtain a masterbatch; S2: At 160-170°C, high-density polyethylene, high-chlorinated polyethylene, and polyvinylidene fluoride were premixed for 10-15 minutes, heated to 170-180°C, and masterbatch and bisaminosilane coupling agent were added. The mixture was mixed for 20-25 minutes, heated to 180-190°C, core-shell graphene and zinc borate were added, and the mixture was mixed for 30-40 minutes. The mixture was cooled to 125-130°C, tert-butyl peroxybenzoate and trimethylolpropane trimethacrylate were added, and the mixture was reacted for 10-15 minutes. The mixture was heated to 145-150°C, di-tert-butyl peroxide was added, and the mixture was reacted for 6-8 minutes. The mixture was cooled to 110-120°C, and antioxidant and anti-aging agent were added. The mixture was mixed for 8-12 minutes to obtain a blend. S3: Extruding the blended material into a tube through an extruder, cooling and shaping, cutting, and aging treatment to obtain a tube.

[0031] In this scheme, an interface-compatible masterbatch of ethylene-acrylic acid copolymer and modified phase-change paraffin is first prepared by melt blending to provide a transition layer for the combination of polar fillers and non-polar matrix; then, the masterbatch and bisaminosilane coupling agent are introduced after the matrix resin is pre-mixed, and the nano-scale dispersion of functional fillers such as core-shell structured graphene and zinc borate in the high-density polyethylene matrix is achieved through the chemical bridging effect of the coupling agent, and a bonding interface is simultaneously constructed to eliminate microscopic defects; through a step-by-step cross-linking process, the inner lining pipe material is given excellent corrosion resistance, aging resistance and high-pressure stability.

[0032] Preferably, in step S2, after adding zinc borate, the method further comprises adding sodium molybdate.

[0033] Preferably, in step S2, after adding polyvinylidene fluoride, the step further includes adding ethylene-octene copolymer and maleic anhydride grafted POE.

[0034] In a third aspect, the present application provides an oil and gas gathering and transportation pipeline, comprising a substrate and the above-mentioned high corrosion-resistant inner lining pipe material, wherein the high corrosion-resistant inner lining pipe material is composited on the inner surface of the substrate.

[0035] Preferably, the substrate is a stainless steel substrate.

[0036] Preferably, an adhesive is used to compound the high corrosion-resistant lining pipe material onto the inner surface of the substrate.

[0037] Preferably, the adhesive is a bisphenol A epoxy resin adhesive, the thickness of the bisphenol A epoxy resin adhesive is 50-100 μm, and the adhesive is cured at room temperature for 12-24 hours.

[0038] Preferably, the stainless steel substrate undergoes the following pretreatment steps before use: surface cleaning and roughening of the stainless steel substrate.

[0039] Preferably, the roughening treatment is sandblasting, so that the inner surface roughness Ra of the stainless steel substrate reaches 1.0-2.0 μm. In summary, the present application has the following beneficial effects: 1. This application uses high-density polyethylene (HDPE) high crystalline phase as a continuous matrix and polyvinylidene fluoride (PVDF) as a dispersed phase. The interfacial tension of the two phases is adjusted by highly chlorinated polyethylene to promote the uniform dispersion of PVDF in the HDPE matrix, forming a dual-continuous phase penetrating network with both high rigidity and polar medium barrier capabilities. The core-shell structured graphene relies on the polar anchoring of graphene oxide, the conductive bridging of reduced graphene oxide, and the coordination effect of the polyimide shell to cooperate with zinc borate to form a chemical passivation film on the surface of the material, thereby achieving multi-scale protection. The modified phase-change paraffin wax achieves in-situ repair of microcracks through phase change and polar group grafting, and cooperates with the antioxidant system to improve the long-term aging resistance of the material. Through interface modification, network construction, and chemical synergy, each component significantly enhances the stability and service life of the material in a high-pressure corrosion environment.

[0040] 2. Sodium molybdate is preferably used in this application. Its anion reacts with H2S to form an extremely insoluble dense layer of molybdenum sulfide, which forms a molybdenum-containing carbonate interface layer through chemical adsorption when reacting with CO2. It has a dual effect of filling the micropores of the material and blocking the penetration of acidic gases. At the same time, sodium molybdate and some zinc ions in the core-shell structure graphene enhance the adsorption stability of H2S / CO2 through a coordination synergistic effect. DETAILED DESCRIPTION

[0041] The present application is further described in detail below with reference to the embodiments.

[0042] Unless otherwise specified, the raw materials used in the examples and comparative examples of the present application are all commercially available.

[0043] Normal paraffin wax is a straight-chain alkane with a carbon chain length of C20~C28, a melting point of 65~70℃, and a phase change latent heat of ≥210J / g; Microcrystalline wax has a carbon chain length of C30~C40, contains branched and cycloalkane structures, and has a melting point of 80~90℃; The molecular weight of 4,4′-diaminodiphenyl ether is 200 g / mol; The sheet diameter of graphene oxide is 5~15μm, the thickness is 1~2nm, and the content of oxygen-containing groups (hydroxyl, epoxy) is 25%~30%; The reduced graphene oxide has a sheet diameter of 5-10 μm, a thickness of 1-2 nm, an oxygen group content of 10%-15%, and an electrical conductivity of ≥10²S / cm; Zinc borate: particle size is 1~3μm.

[0044] Preparation Examples 1-3 Modified Phase Change Paraffin Wax Preparation Example 1 The preparation method of the modified phase-change paraffin wax of this preparation example comprises the following steps: Under a nitrogen atmosphere, 75g of normal paraffin wax and 25g of microcrystalline wax were put into a reactor, heated to 75°C, stirred and mixed at a rate of 300rpm for 25min, then heated to 105°C at a heating rate of 2°C / min, stirred and mixed for 35min, 8g of glycidyl methacrylate was added, stirred and mixed for 10min, then 0.84g of benzoyl peroxide was added, heated to 125°C, stirred and reacted at a rate of 200rpm for 60min, 0.36g of benzoyl peroxide was added, heated to 135°C, stirred and reacted for 90min, and then a sample was dropped into anhydrous ethanol. If the precipitate was uniformly milky white and had no oily stratification, it indicated that The grafting reaction is complete; otherwise, the reaction time needs to be extended by 15 to 30 minutes. After the reaction is completed, cool to 80°C, add 3 times the volume of n-hexane, maintain 80°C, stir for 60 minutes, centrifuge, separate the n-hexane solution containing impurities in the upper layer, repeat washing with n-hexane twice, transfer to a rotary evaporator, vacuum distill at 60°C for 30 minutes, continue distillation until the difference between two consecutive weighings is less than 0.05%, cool to room temperature, crush to a particle size of less than 2 mm, transfer to a ball mill and grind for 30 minutes, sieve to obtain 50 to 100 μm particles, add zinc stearate accounting for 0.5% of the mass of 50 to 100 μm particles, mix well, and obtain.

[0045] Preparation Example 2 The preparation method of the modified phase-change paraffin wax of this preparation example comprises the following steps: Under nitrogen atmosphere, 70g normal paraffin wax and 30g microcrystalline wax were put into the reactor, heated to 80°C, stirred and mixed at a rate of 300rpm for 20min, then heated to 110°C at a heating rate of 2°C / min, stirred and mixed for 30min, 5g glycidyl methacrylate was added, stirred and mixed for 10min, and then 1g benzoyl peroxide was added, heated to 120°C, stirred and reacted at a rate of 200rpm for 70min, 0.5g benzoyl peroxide was added, heated to 130°C, stirred and reacted for 100min, and then a sample was taken and dropped into anhydrous ethanol. If the precipitate was uniformly milky white and there was no oily stratification, it indicated that the grafting The reaction is complete; otherwise, the reaction time needs to be extended by 15 to 30 minutes. After the reaction is completed, cool to 80°C, add 3 times the volume of n-hexane, maintain 80°C, stir for 60 minutes, centrifuge, separate the n-hexane solution containing impurities in the upper layer, repeat washing with n-hexane twice, transfer to a rotary evaporator, vacuum distill at 60°C for 30 minutes, continue distillation until the difference between two consecutive weighings is less than 0.05%, cool to room temperature, crush to a particle size of less than 2 mm, transfer to a ball mill and grind for 30 minutes, sieve to obtain 50 to 100 μm particles, add zinc stearate accounting for 0.5% of the mass of the 50 to 100 μm particles, mix well, and obtain.

[0046] Preparation Example 3 The preparation method of the modified phase-change paraffin wax of this preparation example comprises the following steps: Under a nitrogen atmosphere, 80g of normal paraffin wax and 20g of microcrystalline wax were put into a reactor, heated to 80°C, stirred and mixed at a rate of 300rpm for 25min, then heated to 100°C at a heating rate of 2°C / min, stirred and mixed for 40min, 10g of glycidyl methacrylate was added, stirred and mixed for 10min, then 0.7g of benzoyl peroxide was added, heated to 130°C, stirred and reacted at a rate of 200rpm for 50min, 0.3g of benzoyl peroxide was added, heated to 140°C, stirred and reacted for 80min, and then a sample was dropped into anhydrous ethanol. If the precipitate was uniformly milky white and had no oily stratification, it indicated that the reaction was complete. If the reaction is complete, the reaction time needs to be extended by 15 to 30 minutes. After the reaction is completed, cool to 80°C, add 3 times the volume of n-hexane, maintain 80°C, stir for 60 minutes, centrifuge, separate the n-hexane solution containing impurities in the upper layer, repeat washing with n-hexane twice, transfer to a rotary evaporator, vacuum distill at 60°C for 30 minutes, continue distillation until the difference between two consecutive weighings is less than 0.05%, cool to room temperature, crush to a particle size of less than 2 mm, transfer to a ball mill and grind for 30 minutes, sieve to obtain 50 to 100 μm particles, add zinc stearate accounting for 0.5% of the mass of the 50 to 100 μm particles, mix well, and obtain the product.

[0047] Preparation Examples 4-6 Core-shell Graphene Preparation Example 4 The preparation method of the core-shell graphene of this preparation example comprises the following steps: In the reactor, 2L N-methylpyrrolidone and 1.3g polyvinylpyrrolidone were added and stirred to mix evenly, and then 50g graphene oxide and 50g reduced graphene oxide were added. The mixture was stirred at a speed of 300rpm for 30min, and then transferred to an ultrasonic device with a power of 200W and a frequency of 20kHz. After ultrasonic treatment for 40min, polyamic acid was slowly added dropwise. After stirring at 25°C for 4h, 1mol acetic anhydride and 0.01mol 4-dimethylaminopyridine were added. The temperature was maintained at 25°C and the reaction was continued for 5h. The mixture was centrifuged and washed with anhydrous ethanol three times to obtain a coating. The coated material was added to 2L of ethanol-water solution and transferred to an ultrasonic device with an ultrasonic power set to 200W. After ultrasonic treatment for 40 minutes, a mixture of 0.2mol of zinc nitrate and 0.3mol of citric acid was added, and the pH was adjusted to 4 with 5% ammonia water. The temperature was raised to 50°C, stirred for reaction for 9 hours, cooled to room temperature, centrifuged, washed 3 times with anhydrous ethanol, transferred to a vacuum drying oven, and dried at 60°C to constant weight to obtain the product.

[0048] The preparation method of polyamic acid comprises the following steps: After 0.5 mol of 4,4′-diaminodiphenyl ether and 500 mL of N-methylpyrrolidone are mixed evenly, the temperature is lowered to 3°C under a nitrogen atmosphere, 0.54 mol of pyromellitic dianhydride is added and mixed evenly, and the mixture is stirred for reaction for 3 h to obtain the product.

[0049] The preparation method of the mixed solution is as follows: 0.3 mol of citric acid is evenly mixed with 200 g of deionized water.

[0050] In the ethanol-water solution, the volume ratio of ethanol to deionized water is 7:3.

[0051] Preparation Example 5 The preparation method of the core-shell graphene of this preparation example comprises the following steps: In the reactor, 2L N-methylpyrrolidone and 0.75g polyvinylpyrrolidone were added and stirred to mix evenly, and then 25g graphene oxide and 50g reduced graphene oxide were added, and stirred at a speed of 300rpm for 30min. Then, the mixture was transferred to an ultrasonic device, set the power to 200W, the frequency to 20kHz, and ultrasonic treatment was carried out for 40min. Then, polyamic acid was slowly added dropwise. After stirring at 30°C for 3h, 0.54mol acetic anhydride and 0.009mol 4-dimethylaminopyridine were added, and the temperature was maintained at 30°C. The reaction was continued for 4h, centrifuged, and washed with anhydrous ethanol three times to obtain a coating. The coated material was added to 2L of ethanol-water solution and transferred to an ultrasonic device with an ultrasonic power set to 200W. After ultrasonic treatment for 40 minutes, a mixture of 0.06mol of zinc nitrate and 0.06mol of citric acid was added, and the pH was adjusted to 5 with 5% ammonia water. The temperature was raised to 40°C, stirred for reaction for 10 hours, cooled to room temperature, centrifuged, washed three times with anhydrous ethanol, transferred to a vacuum drying oven, and dried at 60°C to constant weight to obtain the product.

[0052] The preparation method of polyamic acid comprises the following steps: After 0.3 mol of 4,4′-diaminodiphenyl ether and 300 mL of N-methylpyrrolidone are mixed evenly, the temperature is lowered to 5°C under a nitrogen atmosphere, 0.315 mol of pyromellitic dianhydride is added and mixed evenly, and the mixture is stirred for reaction for 2 h to obtain the product.

[0053] The preparation method of the mixed solution is as follows: 0.06 mol of citric acid and 100 g of deionized water are mixed evenly to obtain the mixed solution.

[0054] In the ethanol-water solution, the volume ratio of ethanol to deionized water is 6:4.

[0055] Preparation Example 6 The preparation method of the core-shell graphene of this preparation example comprises the following steps: In the reactor, 2L N-methylpyrrolidone and 1.88g polyvinylpyrrolidone were added and stirred until uniform, and then 75g graphene oxide and 50g reduced graphene oxide were added. The mixture was stirred at a speed of 300rpm for 30min, and then transferred to an ultrasonic device with a power of 200W and a frequency of 20kHz. After ultrasonic treatment for 40min, polyamic acid was slowly added dropwise. After stirring at 30°C for 5h, 1.65mol acetic anhydride and 0.03mol 4-dimethylaminopyridine were added. The temperature was maintained at 30°C and the reaction was continued for 6h. The mixture was centrifuged and washed three times with anhydrous ethanol to obtain a coating. The coated material was added to 2L of ethanol aqueous solution and transferred to an ultrasonic device with an ultrasonic power set to 200W. After ultrasonic treatment for 40 minutes, a mixture of 0.28mol of zinc nitrate, 0.1mol of copper nitrate and 0.45mol of citric acid was added, and the pH was adjusted to 3 with 8% ammonia water. The temperature was raised to 60°C, stirred for reaction for 8 hours, cooled to room temperature, centrifuged, washed 3 times with anhydrous ethanol, transferred to a vacuum drying oven, and dried at 60°C to constant weight to obtain the product.

[0056] The preparation method of polyamic acid comprises the following steps: After 0.75 mol of 4,4′-diaminodiphenyl ether and 750 mL of N-methylpyrrolidone are mixed evenly, the temperature is lowered to 0°C under a nitrogen atmosphere, 0.825 mol of pyromellitic dianhydride is added and mixed evenly, and the mixture is stirred for reaction for 5 h to obtain the product.

[0057] The preparation method of the mixed solution is as follows: 0.45 mol of citric acid and 200 g of deionized water are mixed evenly to obtain the mixed solution.

[0058] In the ethanol-water solution, the volume ratio of ethanol to deionized water is 7:3.

[0059] Example 1 The high corrosion-resistant liner pipe material of this embodiment is prepared from the following raw materials: 1000g high-density polyethylene, 180g highly chlorinated polyethylene, 80g polyvinylidene fluoride, 40g zinc borate, 120g modified phase change paraffin, 30g core-shell graphene, 40g ethylene-acrylic acid copolymer, 20g bisaminosilane coupling agent, 3g tert-butyl perbenzoate, 3g trimethylolpropane trimethacrylate, 6g di-tert-butyl peroxide, 5g antioxidant, and 3g anti-aging agent; Among them, the modified phase change paraffin comes from Preparation Example 1; the core-shell structure graphene comes from Preparation Example 4; The bisaminosilane coupling agent is N-(2-aminoethyl)-3-aminopropyltrimethoxysilane; The antioxidants were 3.5 g of Antioxidant 1010 and 1.5 g of Antioxidant 168; The antioxidant is light stabilizer 770.

[0060] The method for preparing the high corrosion-resistant inner lining pipe material of this embodiment includes the following steps: S1: Add ethylene-acrylic acid copolymer to a high-speed mixer, heat to 110°C, stir for 5 minutes, cool to 85°C, slowly add modified phase-change paraffin wax preheated to liquid for about 10 minutes with continuous stirring, then heat to 125°C, mix for 10 minutes, and transfer to an extruder. After the extruded strips are cooled at a wind speed of 3 m / s, they are pelletized to a particle size of about 3 mm and transferred to a vacuum drying oven for drying at 50°C for 2 hours to obtain masterbatch; S2: At 160°C, high-density polyethylene, high-chlorinated polyethylene, and polyvinylidene fluoride were added to an internal mixer and mixed for 10 minutes. The temperature was raised to 170°C, and the masterbatch and bisaminosilane coupling agent were added. The mixing was continued for 20 minutes. The temperature was further raised to 180°C, and core-shell graphene and zinc borate were added. The mixture was mixed for 30 minutes. The temperature was lowered to 125°C, and tert-butyl peroxybenzoate and trimethylolpropane trimethacrylate were added. The mixture was pre-crosslinked for 10 minutes. The temperature was raised to 145°C, and di-tert-butyl peroxide was added. The mixture was subjected to a secondary crosslinking reaction for 6 minutes. The temperature was lowered to 110°C, and an antioxidant and an anti-aging agent were added. The mixture was mixed for 8 minutes to obtain a blend. S3: The blended material is conveyed to the extruder hopper and extruded into a tube through a die. The tube enters a vacuum sizing sleeve (vacuum degree -0.07MPa, water temperature 15℃) for cooling and shaping, and then is further cooled by a spray cooling water tank (section temperature control: front section 30℃, middle section 25℃, rear section 20℃). The cooled tube is uniformly led out by a traction machine, cut to a fixed length, and then transferred to a 60℃ oven for aging treatment for 4h. It is then naturally cooled to room temperature.

[0061] In step S1, the extruder parameters are set as follows: hopper section 120°C, conveying section 125°C, melting section 130°C, mixing section 135°C, head section 130°C; screw speed is 180 rpm; In step S3, the extruder parameters are set as follows: feeding section 170°C, compression section 190°C, metering section 200°C, connector 205°C, die 205°C, screw speed 40 rpm, and traction speed of the traction machine 1.0 m / min.

[0062] The oil and gas gathering and transportation pipeline of this embodiment includes a 316 stainless steel pipe and a high-corrosion-resistant inner lining pipe material. The inner wall of the 316 stainless steel pipe is wiped with anhydrous ethanol and naturally dried in the shade. The inner wall of the 316 stainless steel pipe is then treated with a sandblasting process with a sandblasting pressure of 0.4 MPa to make the inner wall roughness Ra reach 1.0 μm. The pipe is then placed in a drying oven at 80°C and dried for 15 minutes. Thereafter, bisphenol A epoxy resin adhesive is sprayed on the inner wall of the 316 stainless steel pipe with a thickness controlled at 50 μm. The pipe is then placed in a constant temperature environment at 25°C and pre-cured for 1 hour. The high-corrosion-resistant inner lining pipe material is inserted into the stainless steel pipe. A hydraulic expander is then used to apply radial pressure (pressure of approximately 1.5 MPa) to the high-corrosion-resistant inner lining pipe material for 10 minutes. The pipe is then placed in a constant temperature environment at 25°C and cured for 12 hours. The pipe is then cut as needed and sealed at both ends to obtain an oil and gas gathering and transportation pipeline.

[0063] Among them, the oil and gas gathering and transportation pipelines use ultrasound to check the interface bonding conditions: tight bonding, no obvious stratification or gaps, and uniform ultrasonic echo.

[0064] Example 2 The high corrosion-resistant liner pipe material of this embodiment is prepared from the following raw materials: 1000g high-density polyethylene, 200g highly chlorinated polyethylene, 100g polyvinylidene fluoride, 50g zinc borate, 130g modified phase change paraffin, 40g core-shell structure graphene, 50g ethylene-acrylic acid copolymer, 30g bisaminosilane coupling agent, 4g tert-butyl perbenzoate, 4g trimethylolpropane trimethacrylate, 7g di-tert-butyl peroxide, 7g antioxidant, and 4g anti-aging agent; Among them, the modified phase change paraffin comes from Preparation Example 2; the core-shell structure graphene comes from Preparation Example 5; The bisaminosilane coupling agent is N-(2-aminoethyl)-3-aminopropyltriethoxysilane; The antioxidants were 5g of Antioxidant 1010 and 2g of Antioxidant 168; The antioxidant is light stabilizer 770.

[0065] The method for preparing the high corrosion-resistant inner lining pipe material of this embodiment includes the following steps: S1: Add ethylene-acrylic acid copolymer to a high-speed mixer, heat to 115°C, stir for 5 minutes, cool to 90°C, slowly add modified phase-change paraffin wax preheated to liquid for about 10 minutes with continuous stirring, then heat to 125°C, mix for 12 minutes, and transfer to an extruder. After the extruded strips are cooled at a wind speed of 3 m / s, they are pelletized to a particle size of about 3 mm and transferred to a vacuum drying oven at 50°C for 2 hours to obtain masterbatch; S2: At 165°C, high-density polyethylene, high-chlorinated polyethylene, and polyvinylidene fluoride were added to an internal mixer and mixed for 13 minutes. The temperature was raised to 175°C, and the masterbatch and bisaminosilane coupling agent were added. The mixing was continued for 23 minutes. The temperature was further raised to 185°C, and core-shell graphene and zinc borate were added. The mixture was mixed for 35 minutes. The temperature was lowered to 125°C, and tert-butyl peroxybenzoate and trimethylolpropane trimethacrylate were added. The mixture was pre-crosslinked for 12 minutes. The temperature was raised to 145°C, and di-tert-butyl peroxide was added. The mixture was secondary crosslinked for 7 minutes. The temperature was lowered to 115°C, and antioxidants and anti-aging agents were added. The mixture was mixed for 10 minutes to obtain a blend. S3: The blended material is conveyed to the extruder hopper and extruded into a tube through a die. The tube enters a vacuum sizing sleeve (vacuum degree -0.07MPa, water temperature 15℃) for cooling and shaping, and then is further cooled by a spray cooling water tank (section temperature control: front section 30℃, middle section 25℃, rear section 20℃). The cooled tube is uniformly led out by a traction machine, cut to a fixed length, and then transferred to a 60℃ oven for aging treatment for 4h. It is then naturally cooled to room temperature.

[0066] In step S1, the extruder parameters are set as follows: hopper section 115°C, conveying section 120°C, melting section 125°C, mixing section 130°C, head section 125°C; screw speed is 180 rpm; In step S3, the extruder parameters are set as follows: feeding section 165°C, compression section 185°C, metering section 195°C, connector 200°C, die 200°C, screw speed 45 rpm, and traction speed of the traction machine 0.8 m / min.

[0067] The oil and gas gathering and transportation pipeline of this embodiment includes a 316 stainless steel pipe and a high-corrosion-resistant inner lining pipe material. The inner wall of the 316 stainless steel pipe is wiped with anhydrous ethanol and naturally dried in the shade. The inner wall of the 316 stainless steel pipe is then treated with a sandblasting process with a sandblasting pressure of 0.5 MPa to make the inner wall roughness Ra reach 1.5 μm. The pipe is then placed in a drying oven at 80°C and dried for 20 minutes. Thereafter, bisphenol A epoxy resin adhesive is sprayed on the inner wall of the 316 stainless steel pipe with a thickness controlled at 75 μm. The pipe is then placed in a constant temperature environment at 25°C and pre-cured for 1.5 hours. The high-corrosion-resistant inner lining pipe material is inserted into the stainless steel pipe. Thereafter, a hydraulic expander is used to apply radial pressure (pressure of approximately 1.5 MPa) to the high-corrosion-resistant inner lining pipe material for 12 minutes. The pipe is then placed in a constant temperature environment at 25°C and cured for 18 hours. The pipe is then cut as needed and sealed at both ends to obtain an oil and gas gathering and transportation pipeline.

[0068] Among them, the oil and gas gathering and transportation pipelines use ultrasound to check the interface bonding conditions: tight bonding, no obvious stratification or gaps, and uniform ultrasonic echo.

[0069] Example 3 The high corrosion-resistant liner pipe material of this embodiment is prepared from the following raw materials: 1000g high-density polyethylene, 220g highly chlorinated polyethylene, 120g polyvinylidene fluoride, 60g zinc borate, 140g modified phase change paraffin, 50g core-shell graphene, 60g ethylene-acrylic acid copolymer, 40g bisaminosilane coupling agent, 5g tert-butyl peroxybenzoate, 5g trimethylolpropane trimethacrylate, 8g di-tert-butyl peroxide, 10g antioxidant, and 5g anti-aging agent; Among them, the modified phase change paraffin comes from Preparation Example 3; the core-shell structure graphene comes from Preparation Example 6; The bisaminosilane coupling agent is N-(2-aminoethyl)-3-aminopropyltrimethoxysilane; The antioxidants were 7g of Antioxidant 1010 and 3g of Antioxidant 168; The antioxidant is light stabilizer 770.

[0070] The method for preparing the high corrosion-resistant inner lining pipe material of this embodiment includes the following steps: S1: Add ethylene-acrylic acid copolymer to a high-speed mixer, heat to 110°C, stir for 10 minutes, cool to 85°C, slowly add modified phase-change paraffin wax preheated to liquid for about 10 minutes with continuous stirring, then heat to 120°C, mix for 15 minutes, and transfer to an extruder. After the extruded strips are cooled at a wind speed of 5 m / s, they are pelletized to a particle size of about 3 mm and transferred to a vacuum drying oven at 50°C for 2 hours to obtain masterbatch; S2: At 170°C, high-density polyethylene, high-chlorinated polyethylene, and polyvinylidene fluoride were added to an internal mixer and mixed for 15 minutes. The temperature was raised to 180°C, and the masterbatch and bisaminosilane coupling agent were added. The mixing was continued for 25 minutes. The temperature was further raised to 190°C, and core-shell graphene and zinc borate were added. The mixture was mixed for 40 minutes. The temperature was lowered to 130°C, and tert-butyl peroxybenzoate and trimethylolpropane trimethacrylate were added. The mixture was pre-crosslinked for 15 minutes. The temperature was raised to 150°C, and di-tert-butyl peroxide was added. The mixture was subjected to a secondary crosslinking reaction for 8 minutes. The temperature was lowered to 120°C, and an antioxidant and an anti-aging agent were added. The mixture was mixed for 12 minutes to obtain a blend. S3: The blended material is conveyed to the extruder hopper and extruded into a tube through a die. The tube enters a vacuum sizing sleeve (vacuum degree -0.07MPa, water temperature 15℃) for cooling and shaping, and then is further cooled by a spray cooling water tank (section temperature control: front section 30℃, middle section 25℃, rear section 20℃). The cooled tube is uniformly led out by a traction machine, cut to a fixed length, and then transferred to a 60℃ oven for aging treatment for 4h. It is then naturally cooled to room temperature.

[0071] In step S1, the extruder parameters are set as follows: hopper section 120°C, conveying section 125°C, melting section 130°C, mixing section 135°C, head section 130°C; screw speed is 180 rpm; In step S3, the extruder parameters are set as follows: feeding section 170°C, compression section 190°C, metering section 200°C, connector 205°C, die 205°C, screw speed 40 rpm, and traction speed of the traction machine 1.2 m / min.

[0072] The oil and gas gathering and transportation pipeline of this embodiment includes a 316 stainless steel pipe and a high-corrosion-resistant inner lining pipe material. The inner wall of the 316 stainless steel pipe is wiped with anhydrous ethanol and naturally dried in the shade. The inner wall of the 316 stainless steel pipe is then treated with a sandblasting process with a sandblasting pressure of 0.6 MPa to make the inner wall roughness Ra reach 2.0 μm. The pipe is then placed in a drying oven at 80°C and dried for 30 minutes. Thereafter, bisphenol A epoxy resin adhesive is sprayed on the inner wall of the 316 stainless steel pipe with a thickness controlled at 100 μm. The pipe is then placed in a constant temperature environment at 25°C and pre-cured for 2 hours. The high-corrosion-resistant inner lining pipe material is inserted into the stainless steel pipe. A hydraulic expander is then used to apply radial pressure (pressure of approximately 1.5 MPa) to the high-corrosion-resistant inner lining pipe material for 15 minutes. The pipe is then placed in a constant temperature environment at 25°C and cured for 24 hours. The pipe is then cut as needed and sealed at both ends to obtain an oil and gas gathering and transportation pipeline.

[0073] Among them, the oil and gas gathering and transportation pipelines use ultrasound to check the interface bonding conditions: tight bonding, no obvious stratification or gaps, and uniform ultrasonic echo.

[0074] Example 4 The difference between this embodiment and embodiment 3 is that: The high corrosion-resistant inner lining pipe material of this embodiment also includes 15g of sodium molybdate.

[0075] In the method for preparing the high corrosion-resistant inner lining pipe material of this embodiment, in step S2, after adding zinc borate, the method further includes adding sodium molybdate.

[0076] Other details are the same as in Example 3.

[0077] Among them, the oil and gas gathering and transportation pipelines use ultrasound to check the interface bonding conditions: tight bonding, no obvious stratification or gaps, and uniform ultrasonic echo.

[0078] Example 5 The difference between this embodiment and embodiment 4 is that: The high corrosion-resistant inner lining pipe material of this embodiment also includes 20g of sodium molybdate.

[0079] Other details are the same as in Example 4.

[0080] Among them, the oil and gas gathering and transportation pipelines use ultrasound to check the interface bonding conditions: tight bonding, no obvious stratification or gaps, and uniform ultrasonic echo.

[0081] Example 6 The difference between this embodiment and embodiment 5 is that: The high corrosion-resistant inner lining pipe material of this embodiment also includes 25g of ethylene-1-octene copolymer and 5g of maleic anhydride grafted POE.

[0082] In the method for preparing the high corrosion-resistant inner lining pipe material of this embodiment, in step S2, after adding polyvinylidene fluoride, the method further includes adding ethylene-octene copolymer.

[0083] Other details are the same as in Example 5.

[0084] Among them, the oil and gas gathering and transportation pipelines use ultrasound to check the interface bonding conditions: tight bonding, no obvious stratification or gaps, and uniform ultrasonic echo.

[0085] Example 7 The difference between this embodiment and embodiment 5 is that: The high corrosion-resistant inner lining pipe material of this embodiment also includes 35g of ethylene-octene copolymer and 8g of maleic anhydride grafted POE.

[0086] Other details are the same as in Example 5.

[0087] Among them, the oil and gas gathering and transportation pipelines use ultrasound to check the interface bonding conditions: tight bonding, no obvious stratification or gaps, and uniform ultrasonic echo.

[0088] Comparative Example 1 The difference between this comparative example and Example 1 is: No modified phase change paraffin was added.

[0089] Other details are the same as in Example 1.

[0090] Among them, the oil and gas gathering and transportation pipelines use ultrasonic inspection to check the interface bonding situation: the ultrasonic echo is disordered and there are defect signals.

[0091] Comparative Example 2 The difference between this comparative example and Example 1 is: Use normal paraffin wax of equal mass to replace the modified phase change paraffin wax.

[0092] Other details are the same as in Example 1.

[0093] Among them, the oil and gas gathering and transportation pipelines use ultrasonic inspection to check the interface bonding situation: the ultrasonic echo is disordered and there are defect signals.

[0094] Comparative Example 3 The difference between this comparative example and Example 1 is: The amount of core-shell graphene remains unchanged; In this comparative example, the preparation method of core-shell graphene comprises the following steps: In the reactor, 2L N-methylpyrrolidone and 1.3g polyvinylpyrrolidone were added and stirred until evenly mixed, and then 100g graphene oxide was added. The mixture was stirred at a speed of 300rpm for 30min, and then transferred to an ultrasonic device with a power of 200W and a frequency of 20kHz. After ultrasonic treatment for 40min, polyamic acid was slowly added dropwise. After stirring at 25°C for 4h, 1mol acetic anhydride and 0.01mol 4-dimethylaminopyridine were added. The temperature was maintained at 25°C and the reaction was continued for 5h. The mixture was centrifuged and washed three times with anhydrous ethanol to obtain a coating. The coated material was added to 2L of ethanol-water solution and transferred to an ultrasonic device with an ultrasonic power set to 200W. After ultrasonic treatment for 40 minutes, a mixture of 0.2mol of zinc nitrate and 0.3mol of citric acid was added, and the pH was adjusted to 4 with 5% ammonia water. The temperature was raised to 50°C, stirred for reaction for 9 hours, cooled to room temperature, centrifuged, washed 3 times with anhydrous ethanol, transferred to a vacuum drying oven, and dried at 60°C to constant weight to obtain the product.

[0095] The preparation method of polyamic acid comprises the following steps: After 0.5 mol of 4,4′-diaminodiphenyl ether and 500 mL of N-methylpyrrolidone are mixed evenly, the temperature is lowered to 3°C under a nitrogen atmosphere, 0.54 mol of pyromellitic dianhydride is added and mixed evenly, and the mixture is stirred for reaction for 3 h to obtain the product.

[0096] The preparation method of the mixed solution is as follows: 0.3 mol of citric acid is evenly mixed with 200 g of deionized water.

[0097] In the ethanol-water solution, the volume ratio of ethanol to deionized water is 7:3.

[0098] Other details are the same as in Example 1.

[0099] Among them, the oil and gas gathering and transportation pipelines use ultrasonic inspection to check the interface connection situation: local signal abnormality.

[0100] Comparative Example 4 The difference between this comparative example and Example 1 is: The amount of core-shell graphene remains unchanged; In this comparative example, the preparation method of core-shell graphene comprises the following steps: In the reactor, 2L N-methylpyrrolidone and 1.3g polyvinylpyrrolidone were added and stirred to mix evenly, and then 50g graphene oxide and 50g reduced graphene oxide were added, and the mixture was stirred at a speed of 300rpm for 30min. Then, the mixture was transferred to an ultrasonic device, the power was set to 200W, the frequency was 20kHz, and after ultrasonic treatment for 40min, polyamic acid was slowly added dropwise. After stirring at 25°C for 4h, 1mol acetic anhydride and 0.01mol 4-dimethylaminopyridine were added, and the temperature was maintained at 25°C. The reaction was continued for 5h, and the mixture was centrifuged and washed with anhydrous ethanol 3 times. The mixture was transferred to a vacuum drying oven and dried at 60°C to constant weight to obtain the product.

[0101] The preparation method of polyamic acid comprises the following steps: After 0.5 mol of 4,4′-diaminodiphenyl ether and 500 mL of N-methylpyrrolidone are mixed evenly, the temperature is lowered to 3°C under a nitrogen atmosphere, 0.54 mol of pyromellitic dianhydride is added and mixed evenly, and the mixture is stirred for reaction for 3 h to obtain the product.

[0102] Among them, the oil and gas gathering and transportation pipelines use ultrasonic inspection to check the interface bonding situation: the ultrasonic echo shows a scattered signal.

[0103] Comparative Example 5 The difference between this comparative example and Example 1 is: S2: At 160°C, high-density polyethylene, high-chlorinated polyethylene, and polyvinylidene fluoride were added to an internal mixer and mixed for 10 minutes. The temperature was raised to 170°C, and the masterbatch and bisaminosilane coupling agent were added. The mixing was continued for 20 minutes. The temperature was further raised to 180°C, and core-shell graphene and zinc borate were added. The mixture was mixed for 30 minutes. The temperature was lowered to 145°C, and di-tert-butyl peroxide and trimethylolpropane trimethacrylate were added. The mixture was cross-linked for 6 minutes. The temperature was lowered to 110°C, and an antioxidant and an anti-aging agent were added. The mixture was mixed for 8 minutes to obtain a blend. Other details are the same as in Example 1.

[0104] Among them, the oil and gas gathering and transportation pipelines use ultrasonic inspection to check the interface bonding conditions: linear debonding defects (no echo area).

[0105] Performance testing 1. Hydrostatic strength test Test basis: SY / T 7415-2018 and Q / SH1020 1889-2020; Testing equipment: pressure testing machine Sample preparation: Cut a 300mm long pipe section from the high corrosion-resistant liner material and machine the sealing surfaces at both ends.

[0106] Test steps: Place the sample in an environment of 23±2℃ and 50±5% RH for 24 hours, then install it in the testing machine and inject a simulated corrosive medium (a saline solution containing 1% H2S+5% CO2, a NaCl mass concentration of 5%, and a pH of 3.5±0.2). Exhaust the air and increase the pressure to the target pressure (hoop stress 5.4MPa) at a rate of 0.5MPa / s. Move the entire sample into a constant temperature water bath and slowly heat it to 80℃ at a heating rate of 3℃ / min. Maintain the temperature for 165 hours and observe whether the sample has cracks, leakage, or bulging. If there is no crack, leakage, or bulging, it is considered to have passed. Rinse the inner wall of the sample with deionized water and measure the wall thickness change with a thickness gauge (accuracy 0.01mm). The specific results are shown in Table 1.

[0107] 2. Mechanical properties test Test basis: SY / T 7415-2018 and GB / T 1040.1-2006; Testing equipment: Universal material testing machine Sample preparation: Dumbbell-shaped specimens with a width of 10 mm and a thickness of 2.0 ± 0.2 mm were cut from the high corrosion-resistant liner pipe material, with 5 specimens per group.

[0108] Test procedure: Place the specimen in an environment of 23±2°C and 50±5% RH for 24 hours, then install it in the fixture of the testing machine and stretch it at a rate of 50 mm / min until it breaks. Calculate the average value and record the tensile strength and elongation at break. The specific results are shown in Table 1.

[0109] 3. Oxidation Induction Time (OIT) Test Test basis: SY / T 7415-2018 and GB / T 19466.6-2009; Sample preparation: 3mm×3mm×1mm thin slices were cut from a uniform part of the high corrosion-resistant liner pipe material, with 10 samples per group.

[0110] Sample pretreatment steps: Place 5 samples from each group into a high-pressure reactor, inject 80°C crude oil, and pass 8MPa nitrogen. After sealing, soak at a constant temperature and pressure for 15 days. Remove the samples, wipe the surface oil stains with anhydrous ethanol, and place them in a vacuum drying oven (50°C) to dry to constant weight for later use.

[0111] Blank control group: wipe the surface of the remaining 5 unaged samples in each group with anhydrous ethanol, place them in a vacuum drying oven (50°C) and dry them to constant weight for later use.

[0112] Test conditions: nitrogen atmosphere (50 mL / min), temperature raised to 200°C, constant temperature for 5 minutes, then switched to oxygen (50 mL / min), and the oxidation induction time was tested. Specific results are shown in Table 1.

[0113] Table 1 Performance test data of high corrosion resistant inner lining pipe materials in Examples 1 to 7 and Comparative Examples 1 to 5

[0114] From the data in Table 1, we can see that: It can be seen from Example 1 and Comparative Examples 1~2 that Example 1 with the addition of modified phase-change paraffin has a longer hydrostatic life, a lower wall thickness change rate, and significantly better tensile strength, elongation at break, and oxidation induction time than Comparative Examples 1~2 without the addition of or using unmodified normal paraffin, indicating that modified phase-change paraffin can effectively improve the corrosion resistance and mechanical properties of the material, while unmodified paraffin leads to performance degradation.

[0115] It can be seen from Example 1 and Comparative Examples 2 to 4 that the core-shell structure without the use of oxidized / reduced graphene compounding and zinc ion introduction will significantly reduce the corrosion resistance due to insufficient filler barrier and antioxidant capacity.

[0116] It can be seen from Example 1 and Comparative Example 5 that the pre-crosslinking process is crucial to forming a dense cross-linked network and improving the high-pressure corrosion stability and aging resistance of the material. Single cross-linking significantly reduces the corrosion resistance due to many network defects.

[0117] Examples 1-5 demonstrate that by optimizing the composition of the components and adding sodium molybdate, corrosion resistance can be further enhanced while maintaining mechanical properties. In Examples 4-5, the addition of sodium molybdate reduced the wall thickness change rate, but slightly decreased the tensile strength. This is primarily because, while sodium molybdate enhances corrosion inhibition, the molybdate group, a polar ionic group, exhibits compatibility differences with nonpolar matrices, which in turn affects tensile strength and elongation at break.

[0118] It can be seen from Examples 5 to 7 that: on the basis of Example 5, after adding ethylene-octene copolymer and maleic anhydride grafted POE, the material toughening effect is significant. Although the wall thickness change rate increases slightly, the interface compatibility is improved by maleic anhydride grafted POE, so that the corrosion resistance decreases under controllable conditions, which is suitable for the requirements of impact resistance under high-pressure corrosion environments.

[0119] This specific embodiment is merely an explanation of the present application and is not a limitation of the present application. After reading this specification, those skilled in the art may make non-creative modifications to the present embodiment as needed, but as long as they are within the scope of the claims of the present application, they are protected by the patent law.

Claims

1. A high corrosion resistance lining pipe material, characterized in that: The invention is prepared by comprising the following raw materials in parts by mass: 100 parts of high-density polyethylene, 18-22 parts of highly chlorinated polyethylene, 8-12 parts of polyvinylidene fluoride, 4-6 parts of zinc borate, 12-14 parts of modified phase change paraffin wax, 3-5 parts of core-shell structure graphene, 4-6 parts of ethylene-acrylic acid copolymer, 2-4 parts of bisaminosilane coupling agent, 0.3-0.5 parts of tert-butyl peroxybenzoate, 0.3-0.5 parts of trimethylolpropane trimethacrylate, 0.6-0.8 parts of di-tert-butyl peroxide, 0.5-1 parts of antioxidant and 0.3-0.5 parts of antioxidant; The core-shell structure graphene has a composite core formed by graphene oxide and reduced graphene oxide as the core, and a shell layer is a polyimide coating layer loaded with metal ions; The modified phase-change paraffin wax is prepared by compounding normal paraffin wax and microcrystalline wax and grafting glycidyl methacrylate with an initiator.

2. The high corrosion resistance lining pipe material according to claim 1, characterized in that: The preparation method of the modified phase-change paraffin wax comprises the following steps: Under an inert atmosphere, add normal paraffin wax and microcrystalline wax into a reactor, heat to 75-110°C, mix evenly, add glycidyl methacrylate and part of the initiator, heat to 120-130°C, react for 50-70 minutes, then add the remaining initiator, heat to 130-140°C, react for 80-100 minutes, cool, wash, purify, and granulate to obtain the product.

3. The high corrosion resistance lining pipe material according to claim 2, characterized in that: The mass ratio of the normal paraffin wax, microcrystalline wax and glycidyl methacrylate is (70-80): (20-30): (5-10).

4. The high corrosion resistance lining pipe material according to claim 1, characterized in that: The method for preparing the core-shell structure graphene comprises the following steps: (1) Graphene oxide, reduced graphene oxide, and a dispersant are uniformly dispersed in N-methylpyrrolidone, and polyamic acid prepared from 4,4′-diaminodiphenyl ether and pyromellitic dianhydride is added and mixed uniformly. After reacting at 25-30°C for 3-5 hours, acetic anhydride and 4-dimethylaminopyridine are added and the reaction is continued for 4-6 hours. The solid-liquid separation and washing are performed to obtain a composite. (2) The complex is dispersed in an ethanol aqueous solution, and after adding metal salt and citric acid, the pH is adjusted to 3-5, the temperature is raised to 40-60°C, the reaction is carried out for 8-10 hours, and the solid-liquid separation is performed, the washing is performed, and the drying is performed to obtain the product.

5. The high corrosion resistance inner lining pipe material according to claim 4, characterized in that: The molar ratio of the 4,4′-diaminodiphenyl ether, acetic anhydride, 4-dimethylaminopyridine, metal salt and citric acid is 1:(1.8-2.2):(0.02-0.04):(0.2-0.5):(0.2-0.6).

6. The high corrosion resistance inner lining pipe material according to claim 4, characterized in that: The preparation method of the polyamic acid comprises the following steps: After mixing 4,4′-diaminodiphenyl ether and N-methylpyrrolidone evenly, cool to 0-5°C under an inert atmosphere, add pyromellitic dianhydride and mix evenly, and react for 2-4 hours to obtain the product; The molar ratio of the pyromellitic dianhydride to 4,4'-diaminodiphenyl ether is (1.05-1.1):

1.

7. The high corrosion resistance inner lining pipe material according to claim 1, characterized in that: The high corrosion-resistant lining pipe material also includes 1.5 to 2 parts by mass of sodium molybdate.

8. A method for preparing a high corrosion-resistant inner lining pipe material according to any one of claims 1 to 6, characterized in that: The steps include: S1: Ethylene-acrylic acid copolymer and modified phase change paraffin are mixed uniformly at 85-125°C, extruded, cooled, and granulated to obtain a masterbatch; S2: At 160-170°C, high-density polyethylene, high-chlorinated polyethylene, and polyvinylidene fluoride were premixed for 10-15 minutes, heated to 170-180°C, and masterbatch and bisaminosilane coupling agent were added. The mixture was mixed for 20-25 minutes, heated to 180-190°C, core-shell graphene and zinc borate were added, and the mixture was mixed for 30-40 minutes. The mixture was cooled to 125-130°C, tert-butyl peroxybenzoate and trimethylolpropane trimethacrylate were added, and the mixture was reacted for 10-15 minutes. The mixture was heated to 145-150°C, di-tert-butyl peroxide was added, and the mixture was reacted for 6-8 minutes. The mixture was cooled to 110-120°C, and antioxidant and anti-aging agent were added. The mixture was mixed for 8-12 minutes to obtain a blend. S3: Extruding the blended material into a tube through an extruder, cooling and shaping, cutting, and aging treatment to obtain a tube.

9. The method for preparing a high corrosion-resistant inner lining pipe material according to claim 8, characterized in that: In step S2, after adding zinc borate, the method further includes adding sodium molybdate.

10. An oil and gas gathering and transportation pipeline, characterized by: It comprises a substrate and the high corrosion resistant inner lining pipe material according to any one of claims 1 to 7, wherein the high corrosion resistant inner lining pipe material is compounded on the inner surface of the substrate.

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