Lining pipe material for oil and gas gathering and transportation pipeline, preparation method of lining pipe material and oil and gas gathering and transportation pipeline

Abstract

The invention relates to the technical field of oil and gas gathering and transportation pipelines, and particularly discloses a lining pipe material for an oil and gas gathering and transportation pipeline, a preparation method of the lining pipe material and the oil and gas gathering and transportation pipeline. The lining pipe material for the oil and gas gathering and transportation pipeline comprises 78-90 parts of polyolefin resin and 10-22 parts of polyolefin resin grafted inorganic heat-conducting filler, the polyolefin resin grafted inorganic heat-conducting filler is prepared from polyolefin resin and inorganic heat-conducting filler by adopting an irradiation crosslinking technology. By adopting a physical irradiation grafting modification method, grafting of the polyolefin and the inorganic heat-conducting filler is realized, the dispersion uniformity of the inorganic heat-conducting filler in a polymer matrix is improved, and the high temperature resistance of the prepared polyolefin pipe is improved.

Description

Technical Field

[0001] The present application relates to the technical field of oil and gas gathering and transportation pipelines. More specifically, it relates to a lining pipe material for oil and gas gathering and transportation pipelines, a preparation method thereof, and an oil and gas gathering and transportation pipeline. Background Art

[0002] Many major oilfields in China have entered the middle and high water cut development periods. With the continuous increase of the comprehensive water cut, the corrosion of the oil and gas gathering system has become increasingly serious. Corrosion has become the key factor affecting the reliability and service life of the pipeline system and is the main cause of pipeline accidents. Due to the presence of a large number of erosive substances in crude oil, such as CO2, H2S, Cl - , a small amount of dissolved oxygen, bacteria, etc., affected by all these factors and their interactions, the oil pipes will inevitably suffer serious corrosion, and the safe production of oilfields is seriously threatened.

[0003] Common well pipe anti-corrosion methods include: nitriding, epoxy powder spraying, titanium nano-spraying, carbon zirconium plating, ultra-high molecular weight polyethylene (UHMWPE) pipe lining, etc. Among these anti-corrosion methods on the market, for nitriding, epoxy powder spraying, etc., the product quality obtained by these anti-corrosion technologies is unstable, the anti-corrosion effect is not ideal, and they lack competitiveness. The UHMWPE pipe lining anti-corrosion technology has the characteristics of light weight, high strength, wear resistance, corrosion resistance, non-scaling, and is hardly eroded by media such as oil, water, and salt. However, UHMWPE still has deficiencies as an oil well lining pipe. The heat distortion temperature of UHMWPE is 55 - 60 °C, and the Vicat softening point is at 120 °C. Due to its intolerance to high temperatures, it cannot be applied in oil wells with a depth exceeding 1200 meters. Below the normal temperature layer, the geothermal temperature gradually increases with the depth. On average, for every 100 meters of depth, the temperature increases by 3 °C. Since most of the oil wells in China exceed 1000 meters, the UHMWPE lining pipe cannot be applied at higher temperatures.

[0004] The patent application document with the publication number CN109096592A discloses a polyolefin composition, a preparation method thereof, and an application. By weight, the preparation raw materials include: 100 parts of ethylene-vinyl alcohol random copolymer, 10 - 50 parts of polypropylene, 1 - 20 parts of thermoplastic polyester elastomer, 0.1 - 15 parts of filler, and the filler is one or more of graphene, graphite, silica, molybdenum dioxide, and talcum powder.

[0005] In this patent application document, only by mixing the ethylene-vinyl alcohol random copolymer, polypropylene, thermoplastic polyester elastomer, and filler, and then extruding and forming through a single-screw extruder, due to the agglomeration of the inorganic heat-conducting filler and its poor compatibility with the polymer matrix, it is difficult to be evenly distributed in the matrix, thereby reducing the high-temperature resistance of the prepared pipe. Summary of the Invention

[0006] In order to improve the dispersion uniformity of inorganic heat-conducting fillers in the polymer matrix and further improve the high-temperature resistance of the prepared polyolefin pipes, the present application provides a lining pipe material for oil and gas gathering and transportation pipelines, its preparation method, and an oil and gas gathering and transportation pipeline.

[0007] In the first aspect, the present application provides a lining pipe material for oil and gas gathering and transportation pipelines, adopting the following technical solution: A lining pipe material for oil and gas gathering and transportation pipelines, comprising 78-90 parts of polyolefin resin and 10-22 parts of polyolefin resin grafted with inorganic heat-conducting fillers; The polyolefin resin grafted with inorganic heat-conducting fillers is prepared by an irradiation cross-linking technology from polyolefin resin and inorganic heat-conducting fillers.

[0008] By adopting the above technical solution, the present application realizes the grafting of polyolefin and inorganic heat-conducting fillers by using a physical irradiation grafting modification method and relying on the physical action of high-energy rays. It can not only improve the heat resistance of the material but also overcome the problems of agglomeration of inorganic heat-conducting fillers and poor compatibility with the polymer matrix, improving the dispersion uniformity of inorganic heat-conducting fillers in the polymer matrix and further improving the high-temperature resistance of the prepared polyolefin pipes.

[0009] Preferably, the inorganic heat-conducting filler is graphene-supported nano-aluminum oxide.

[0010] By adopting the above technical solution, both graphene and aluminum oxide have excellent thermal stability. By loading nano-aluminum oxide on graphene, compared with simple physical mixing, it can not only exert a synergistic effect of "1 + 1 > 2" but also reduce the dosage of expensive fillers through the combination of cheap fillers and expensive fillers, thus effectively reducing costs.

[0011] Preferably, the preparation method of the polyolefin grafted with inorganic heat-conducting fillers comprises the following steps: (1) Mix 1 part by weight of graphene with 10-100 parts by weight of deionized water, and then add 0.01-0.05 part by weight of vinyl silane coupling agent, and perform ultrasonic treatment to obtain a graphene dispersion; (2) Mix 1 part by weight of nano-aluminum oxide with (10-50) parts by weight of ethanol to obtain a nano-aluminum oxide dispersion. Mix the graphene dispersion and the nano-aluminum oxide dispersion, perform ultrasonic treatment, and then dry to obtain vinyl silane-modified graphene-supported nano-aluminum oxide; (3) Mix 1 part by weight of vinyl silane-modified graphene-supported nano-aluminum oxide with 0.001-0.01 part by weight of cross-linking agent to obtain a mixed filler, and then add 0.1-0.3 part by weight of polyolefin resin and perform melt mixing to obtain a resin mixed filler. Treat it with an electron beam with a radiation energy of 1-5 MeV and a radiation beam current of 5-50 mA to obtain polyolefin grafted with inorganic heat-conducting fillers.

[0012] By adopting the above technical solution, graphene not only has excellent thermal conductivity, but also has good adsorption performance. It has porous channels inside, a large specific surface area, and a three-dimensional wrinkled structure with a wavy surface, which can stably load nano-aluminum oxide, realizing the composite of nano-aluminum oxide and graphene. It not only does not reduce the thermal conductivity of nano-aluminum oxide, but also can avoid the agglomeration between nano-aluminum oxide particles, improving the high-temperature resistance of the material. At the same time, under the action of irradiation in this application, the vinyl silane modified graphene loaded with nano-aluminum oxide, cross-linking agent and polyolefin interact with each other, realizing the grafting of polyolefin and inorganic particles. The method is simple, the preparation efficiency is high, and it has good binding properties with the matrix polyolefin resin, further improving the high-temperature resistance of the prepared material.

[0013] Preferably, the preparation method of the graphene is as follows: graphite is acidified and then thermally expanded to obtain expanded graphite, and the expanded graphite is placed in an ethanol solution and ultrasonically treated to obtain graphene.

[0014] By adopting the above technical solution, on the one hand, the acidification treatment of graphite is beneficial to fully and completely activate the graphite. There are substances such as protonic acid and water between the graphite layers, which can increase the internal pores of the graphite. The formed acidified graphite has a rough and hard surface, a large specific surface area, a high porosity, and good adsorption performance. After heating, the substances retained between the layers volatilize or form volatile substances, so the volume of the substances between the layers expands significantly, expanding the distance between the graphite layers, increasing the internal pores of the graphite, and having better adsorption performance, further improving the loading rate of nano-aluminum oxide on graphene. On the other hand, when the expanded graphite is ultrasonically treated, due to the impact of strong sound waves on the solid-liquid interface, transient cavities will be generated, resulting in non-uniform collapse, and thus microjets that impact the solid surface will be generated, which can strengthen mass transfer, improve the surface activity of the solid, and greatly increase the reaction rate. Ultrasonic waves can make substances move violently and forcefully, generating a unidirectional force to accelerate the transfer and diffusion of substances, and can peel substances from the surface. Therefore, even in a very short time, the layer spacing of graphene can be enlarged. Therefore, the ultrasonic treatment process is simple, requires a short time, consumes less energy, has a low cost, and has high efficiency. The graphene after ultrasonic treatment not only makes the expanded graphite quickly exfoliate to form graphene, but also can further increase the layer spacing of graphene, which is more conducive to the loading of nano-aluminum oxide.

[0015] Preferably, the preparation method of the expanded graphite is as follows: graphite is reacted with concentrated sulfuric acid, ammonium disulfate and a treatment solution containing hydrogen peroxide.

[0016] By adopting the above technical solution, sulfuric acid in the treatment liquid reacts with graphite, a part of carbon constituting the graphite interlayer structure forms cations, combines with the bisulfate ions formed by the decomposition of sulfuric acid, and generates an ionic compound to be stored between the graphite layers, so as to expand the interlayer gap of graphite, thereby improving the adsorption of expanded graphite to nano-aluminum oxide and increasing the loading rate of nano-aluminum oxide on graphene.

[0017] Preferably, the nano-aluminum oxide is a mixture of nano-spherical aluminum oxide with an average particle size of 5 - 10 nm and nano-spherical aluminum oxide with an average particle size of 20 - 50 nm in a mass ratio of (5 - 7):(3 - 5).

[0018] By adopting the above technical solution, nano-spherical aluminum oxide has the characteristics of high strength, high hardness, good stability, large specific surface area, good fluidity, and good thermal conductivity compared with other forms of nano-aluminum oxide; loading nano-spherical aluminum oxides with different particle sizes on graphene can fill different pore diameters of graphene, further increasing the loading rate of nano-aluminum oxide on graphene.

[0019] Preferably, the vinyl silane coupling agent is one or more of vinyltrimethoxysilane, vinyltriethoxysilane, vinyltris(β - methoxyethoxy)silane, vinyltri - tert - butoxysilane, vinyltri - tert - butylperoxysilane, and vinyltriacetoxysilane.

[0020] Preferably, the polyolefin resin is one or more of ethylene - vinyl alcohol random copolymer, polyethylene, polypropylene, and polyolefin elastomer.

[0021] Preferably, the melt mass flow rate of the ethylene - vinyl alcohol random copolymer is 0.7 - 10 g / min.

[0022] Preferably, the polyethylene is linear low - density polyethylene with a density of 0.920 - 0.930 g / cm 3 ³.

[0023] Preferably, the polypropylene is a copolymer polypropylene and / or a homopolymer polypropylene with a melt mass flow rate of 0.1 - 5 g / min.

[0024] Preferably, the polyolefin elastomer is an ethylene - octene copolymer with a density of 0.86 - 0.90 g / cm 3 ³.

[0025] By adopting the above technical solution, the ethylene - vinyl alcohol random copolymer is a crystalline polymer with a chain - like molecular structure, having excellent gas barrier properties and thermal stability, which can effectively prevent the penetration of oxygen, carbon monoxide, and other gases, and improve the corrosion resistance of the material.

[0026] Linear low density polyethylene has good tolerance to alcohols, dilute alkalis and acids, and has good processing performance and good barrier properties.

[0027] Polypropylene is a thermoplastic resin with good corrosion resistance to chemicals such as acids, alkalis, and salts, and can work stably under high temperature, high pressure and harsh environments; it has a relatively high melting point and can maintain stable performance at high temperatures, with good mechanical properties, high tensile strength and impact strength, and is more suitable for preparing the inner lining material of oil and gas gathering and transportation pipelines; Ethylene-octene copolymer has a very narrow molecular weight distribution and a short branched chain structure, and has excellent physical and mechanical properties such as high elasticity, high strength, and high elongation. The narrow molecular weight distribution makes the material not prone to flexure during the extrusion processing, and has excellent processing performance; at the same time, due to the saturated structure of the macromolecular chain of ethylene-octene copolymer, it has excellent heat aging and anti-ultraviolet properties.

[0028] According to the needs, one or several of the above polyolefin resins can be selected in this application, which can improve the diversity of the inner lining of the oil and gas gathering and transportation pipelines made, thus expanding the application range.

[0029] In a second aspect, this application provides a preparation method for an inner lining pipe for an oil and gas gathering and transportation pipeline, and adopts the following technical solution: A preparation method for an inner lining pipe for an oil and gas gathering and transportation pipeline is: mixing a polyolefin resin and a polyolefin resin grafted with an inorganic heat-conducting filler according to a ratio and extruding and molding to obtain.

[0030] In a third aspect, this application provides an oil and gas gathering and transportation pipeline, and adopts the following technical solution: An oil and gas gathering and transportation pipeline sequentially includes the inner lining pipe for the oil and gas gathering and transportation pipeline, a reinforcing pipe and an outer pipe from the inside to the outside.

[0031] In summary, this application has the following beneficial effects: 1. By adopting the physical irradiation grafting modification method, this application realizes the grafting of polyolefin and inorganic heat-conducting filler by means of the physical action of high-energy rays. It can not only improve the heat resistance of the material, but also overcome the problems of agglomeration of inorganic fillers and poor compatibility with the polymer matrix, improve the dispersion uniformity of inorganic fillers in the polymer matrix, and further improve the high-temperature resistance of the prepared polyolefin pipe.

[0032] 2. The inorganic heat-conducting filler in this application is graphene-supported nano-aluminum oxide. By loading nano-aluminum oxide on graphene, compared with simple physical mixing, it can not only exert a synergistic effect of "1 + 1 > 2", but also through the combination of cheap fillers and expensive fillers, reduce the dosage of expensive fillers, thereby effectively reducing costs.

[0033] 3. In this application, expanded graphite is obtained by subjecting graphite to acid treatment followed by high-temperature expansion. The expanded graphite is placed in an ethanol solution and treated by ultrasonic waves to obtain graphene. On the one hand, the interlayer distance of graphite can be enlarged after expansion. On the other hand, after ultrasonic treatment of the expanded graphite, not only can the expanded graphite be quickly peeled off to form graphene, but also the interlayer distance of graphene can be further increased, which is more conducive to the loading of nano-aluminum oxide. Detailed Embodiment

[0034] The following further elaborates on this application in conjunction with embodiments.

[0035] The raw materials in the embodiments and comparative examples of this application are all commercially available.

[0036] Preparation Examples 1 - 3 of Graphene Preparation Example 1 Mix 1 ml of 98 wt% concentrated sulfuric acid, 0.1 ml of 3 wt% hydrogen peroxide solution, and 0.1 ml of saturated ammonium persulfate solution to form a treatment solution. While stirring the treatment solution, add 2 g of graphite in 10 portions. After reacting for 30 min, add 1 L of deionized water (water temperature < 10°C) and continuously stir to achieve the purpose of activation. Activate at room temperature for 24 h; convey the activated graphite to a dryer for drying to obtain pretreated graphite, with a drying temperature of 120°C and water content ≤ 5%; granulate the pretreated graphite using a granulator, and control the average particle size at 100 μm; calcine the granulated material at a temperature of 600°C to obtain expanded graphite; Place the above-expanded graphite in 20 g of 25 wt% ethanol solution, and treat it with a 40 kHz probe ultrasonic wave at 25°C for 30 min to obtain a graphene dispersion. Filter the graphene dispersion, wash it with distilled water, redisperse it with water, and dry it to obtain graphene powder.

[0037] Preparation Example 2 Mix 1 ml of 98 wt% concentrated sulfuric acid, 0.1 ml of 3 wt% hydrogen peroxide solution, and 0.1 ml of saturated ammonium persulfate solution to form a treatment solution. While stirring the treatment solution, add 2 g of graphite in 10 portions. After reacting for 30 min, add 1 L of deionized water (water temperature < 10°C) and continuously stir to achieve the purpose of activation. Activate at room temperature for 24 h; convey the activated graphite to a dryer for drying to obtain pretreated graphite, with a drying temperature of 140°C and water content ≤ 5%; granulate the pretreated graphite using a granulator, and control the average mesh number at 150; calcine the granulated material at a temperature of 550°C to obtain expanded graphite; Place the above-expanded graphite in 20 g of 25 wt% ethanol solution, and treat it with a 30 kHz probe ultrasonic wave at 25°C for 40 min to obtain a graphene dispersion. Filter the graphene dispersion, wash it with distilled water, redisperse it with water, and then dry it to obtain graphene powder.

[0038] Preparation Example 3 Mix 1 ml of 98 wt% concentrated sulfuric acid, 0.1 ml of 3 wt% hydrogen peroxide solution, and 0.1 ml of saturated ammonium persulfate solution to form a treatment solution. While stirring the treatment solution, add 2 g of graphite in 10 portions. After reacting for 30 min, add 1 L of deionized water (water temperature < 10°C) and continuously stir to achieve the purpose of activation. Activate at room temperature for 24 h; transfer the activated graphite to a dryer for drying to obtain pretreated graphite, with a drying temperature of 160°C and a water content ≤ 5%; granulate the pretreated graphite using a granulator, and control the average mesh number at 200 μm; calcine the granulated material at a temperature of 500°C to obtain expanded graphite; Place the above expanded graphite in 20 g of 25 wt% ethanol solution, and treat it with ultrasonic waves at 25 kHz using a probe for 60 min at 25°C to obtain a graphene dispersion. Filter the graphene dispersion, wash it with distilled water, redisperse it with water, and then dry it to obtain graphene powder.

[0039] Preparation Examples 4 - 11 Polyolefin Resin Grafted Inorganic Thermal Conductive Filler Preparation Example 4 (1) Mix 10 g of graphene and 100 g of deionized water, then add 0.1 g of vinyltrimethoxysilane, and ultrasonically treat it at a power of 200 W for 1 h to obtain a dispersion. Filter the dispersion, wash it with distilled water, and dry it to obtain vinyltrimethoxysilane-modified graphene; (2) Melt-mix 10 g of vinyltrimethoxysilane-modified graphene and 1 g of ethylene-vinyl alcohol random copolymer with a melt mass flow rate of 5 g / min to obtain a resin mixed filler, and obtain a polyolefin grafted inorganic thermal conductive filler after electron beam treatment with a radiation energy of 1.5 MeV and a radiation beam current of 5 mA.

[0040] Preparation Example 5 (1) Mix 10 g of graphene and 100 g of deionized water, then add 0.1 g of vinyltrimethoxysilane, and ultrasonically treat it at a power of 200 W for 1 h to obtain a vinyltrimethoxysilane-modified graphene dispersion; (2) Mix 10 g of nano-spherical alumina with 100 g of ethanol solution to obtain a nano-alumina dispersion; mix the vinyltrimethoxysilane-modified graphene dispersion and the nano-alumina dispersion, add 0.3 g of polyvinylpyrrolidone, stir for 1 h, and then ultrasonically treat it at a ultrasonic frequency of 40 kHz and a power of 300 W for 30 min to prepare a homogeneous mixture. Filter the mixture, wash it with distilled water, and dry it to obtain vinyltrimethoxysilane-modified graphene supported nano-alumina; (3) Mix 10 g of vinyltrimethoxysilane-modified graphene loaded with nano-aluminum oxide and 0.01 g of triallyl isocyanurate to obtain a mixed filler. Melt-mix the mixed filler with 1 g of ethylene-vinyl alcohol random copolymer with a melt mass flow rate of 5 g / min to obtain a resin mixed filler. After electron beam treatment with a radiation energy of 1.5 MeV and a radiation beam current of 5 mA, a polyolefin grafted inorganic heat-conducting filler is obtained.

[0041] The preparation method of nano-spherical aluminum oxide is as follows: Put 0.1 mol of aluminum sec-butoxide into a gasifier and heat it to 230 °C to vaporize it; Mix the vaporized gas with 1.5 mol of natural gas and 0.2 mol of oxygen and burn it at 1300 °C; Mix the combustion product with cooling water to obtain an aluminum oxide suspension, and spray-dry and grind the aluminum oxide suspension to obtain nano-spherical aluminum oxide particles with an average particle size of 20 nm.

[0042] Preparation Example 6 This preparation example is basically the same as Preparation Example 5, except that the graphene is from Preparation Example 1.

[0043] Preparation Example 7 This preparation example is basically the same as Preparation Example 5, except that the graphene is from Preparation Example 2.

[0044] Preparation Example 8 This preparation example is basically the same as Preparation Example 5, except that the graphene is from Preparation Example 3.

[0045] Preparation Example 9 (1) Mix 10 g of graphene and 500 g of deionized water, then add 0.3 g of vinyltriethoxysilane, and ultrasonically treat it at a power of 200 W for 1 h to obtain a vinyltrimethoxysilane-modified graphene dispersion; (2) Mix 10 g of nano-spherical aluminum oxide with 300 g of ethanol solution to obtain a nano-aluminum oxide dispersion; Mix the obtained vinyltrimethoxysilane-modified graphene dispersion and nano-aluminum oxide dispersion and add 0.3 g of polyvinylpyrrolidone, stir for 1 h, and then ultrasonically treat it at an ultrasonic frequency of 40 kHz and a power of 300 W for 30 min to make a uniform mixture. Filter the mixture, wash it with distilled water, and dry it to obtain a vinyltrimethoxysilane-modified graphene loaded with nano-aluminum oxide after drying the dispersion; (3) Mix 10 g of vinyltrimethoxysilane-modified graphene supported nano-aluminum oxide with 0.05 g of triallyl isocyanurate to obtain a mixed filler. Melt-mix the mixed filler with 1 g of ethylene-vinyl alcohol random copolymer with a melt mass flow rate of 5 g / min and 1 g of copolymerized polypropylene with a melt mass flow rate of 2 g / min to obtain a resin mixed filler. After electron beam treatment with a radiation energy of 1.5 MeV and a radiation beam current of 5 mA, a polyolefin grafted inorganic heat-conducting filler is obtained.

[0046] Among them, the graphene is from Preparation Example 2; The preparation method of nano-spherical aluminum oxide is as follows: Put 0.1 mol of aluminum sec-butoxide into a gasifier and heat it to 230 °C to vaporize it; Mix the vaporized gas with 1.5 mol of natural gas and 0.2 mol of oxygen and burn them at 1300 °C; Mix the combustion product with cooling water to obtain an aluminum oxide suspension, and perform spray drying and grinding on the aluminum oxide suspension to obtain nano-spherical aluminum oxide particles with an average particle size of 20 nm.

[0047] Preparation Example 10 (1) Mix 10 g of graphene and 1 Kg of deionized water, then add 0.5 g of vinyltriethoxysilane, and perform ultrasonic treatment for 1 h at a power of 200 W to obtain a vinyltrimethoxysilane-modified graphene dispersion; (2) Mix 10 g of nano-spherical aluminum oxide with 500 g of ethanol solution to obtain a nano-aluminum oxide dispersion; Mix the vinyltrimethoxysilane-modified graphene dispersion and the nano-aluminum oxide dispersion, add 0.3 g of polyvinylpyrrolidone, stir for 1 h, and then perform ultrasonic treatment for 30 min at a ultrasonic frequency of 40 kHz and a power of 300 W to make a uniform mixture. Filter the mixture, wash it with distilled water, and dry it to obtain a vinyltrimethoxysilane-modified graphene supported nano-aluminum oxide after drying the dispersion; (3) Mix 10 g of vinyltrimethoxysilane-modified graphene supported nano-aluminum oxide with 0.1 g of triallyl isocyanurate to obtain a mixed filler. Melt-mix the mixed filler with 1 g of ethylene-vinyl alcohol random copolymer with a melt mass flow rate of 5 g / min, 1 g of copolymerized polypropylene with a melt mass flow rate of 2 g / min, and 1 g of linear low-density polyethylene with a density of 0.920 g / cm 3 to obtain a resin mixed filler. After electron beam treatment with a radiation energy of 1.5 MeV and a radiation beam current of 5 mA, a polyolefin grafted inorganic heat-conducting filler is obtained.

[0048] Among them, the graphene is from Preparation Example 2; The preparation method of nano-spherical alumina is as follows: 0.1 mol of aluminum sec-butoxide is placed in a gasification furnace and heated to 230 °C to vaporize it; the vaporized gas is mixed with 1.5 mol of natural gas and 0.2 mol of oxygen and burned at 1300 °C; the combustion product is mixed with cooling water to obtain an alumina suspension, and the alumina suspension is spray-dried and ground to obtain nano-spherical alumina particles with an average particle size of 20 nm.

[0049] Preparation Example 11 This preparation example is basically the same as Preparation Example 10, except that (2) 4 g of nano-spherical alumina with an average particle size of 20 nm and 6 g of nano-spherical alumina with an average particle size of 5 nm are mixed with 500 g of ethanol solution to obtain a nano-alumina dispersion; the vinyltrimethoxysilane-modified graphene dispersion and the nano-alumina dispersion are mixed and 0.3 g of polyvinylpyrrolidone is added, and after stirring for 1 h, it is ultrasonically treated at an ultrasonic frequency of 40 kHz and a power of 300 W for 30 min to form a homogeneous mixture, and the mixture is filtered, washed with distilled water, and dried to obtain vinyltrimethoxysilane-modified graphene-supported nano-alumina.

[0050] Among them, the preparation method of nano-spherical alumina is as follows: 0.1 mol of aluminum sec-butoxide is placed in a gasification furnace and heated to 230 °C to vaporize it; the vaporized gas is mixed with 1.5 mol of natural gas and 0.2 mol of oxygen and burned at 1300 °C; the combustion product is mixed with cooling water to obtain an alumina suspension, and the alumina suspension is divided into two parts and spray-dried and ground respectively to obtain nano-spherical alumina particles with an average particle size of 20 nm and 5 nm.

[0051] Example 1 This example provides a lining pipe material for oil and gas gathering and transportation pipelines, including 78 g of ethylene-vinyl alcohol random copolymer with a melt mass flow rate of 5 g / min and 22 g of polyolefin resin grafted with inorganic heat-conducting filler; Among them, the polyolefin resin grafted with inorganic heat-conducting filler is from Preparation Example 4.

[0052] This example also provides a preparation method of the above-mentioned lining pipe for oil and gas gathering and transportation pipelines, including the following steps: The ethylene-vinyl alcohol random copolymer and the polyolefin resin grafted with inorganic heat-conducting filler are mixed according to the above ratio and then transported to a single-screw extruder to extrude the pipe, and the extrusion temperature is 200 °C.

[0053] This example also provides an above-mentioned oil and gas gathering and transportation pipeline, which sequentially includes the above-mentioned lining pipe for oil and gas gathering and transportation pipelines, a reinforcing pipe prepared from continuous fiber materials, and an outer pipe prepared from thermoplastic plastics from the inside to the outside.

[0054] Example 2 This example is basically the same as Example 1, except that the polyolefin resin grafted with inorganic heat-conducting filler is from Preparation Example 5.

[0055] Example 3 This example is basically the same as Example 1, except that the polyolefin resin grafted with inorganic heat-conducting filler is from Preparation Example 6.

[0056] Example 4 This example is basically the same as Example 1, except that the polyolefin resin grafted with inorganic heat-conducting filler is from Preparation Example 7.

[0057] Example 5 This example is basically the same as Example 1, except that the polyolefin resin grafted with inorganic heat-conducting filler is from Preparation Example 8.

[0058] Example 6 This example is basically the same as Example 1, except that this example provides a lining pipe material for oil and gas gathering and transportation pipelines, including 39 g of ethylene-vinyl alcohol random copolymer with a melt mass flow rate of 5 g / min, 39 g of copolymerized polypropylene with a melt mass flow rate of 2 g / min, and 22 g of polyolefin resin grafted with inorganic heat-conducting filler; Among them, the polyolefin resin grafted with inorganic heat-conducting filler is from Preparation Example 9.

[0059] Example 7 This example is basically the same as Example 1, except that this example provides a lining pipe material for oil and gas gathering and transportation pipelines, including 26 g of ethylene-vinyl alcohol random copolymer with a melt mass flow rate of 5 g / min, 26 g of copolymerized polypropylene with a melt mass flow rate of 2 g / min, 26 g of linear low-density polyethylene with a density of 0.920 g / cm 3 and 60 g of polyolefin resin grafted with inorganic heat-conducting filler; Among them, the polyolefin resin grafted with inorganic heat-conducting filler is from Preparation Example 10.

[0060] Example 8 This example is basically the same as Example 7, except that the polyolefin resin grafted with inorganic heat-conducting filler is from Preparation Example 11.

[0061] Example 9 This example is basically the same as Example 8, except that this example provides a lining pipe material for oil and gas gathering and transportation pipelines, including 28 g of ethylene-vinyl alcohol random copolymer with a melt mass flow rate of 5 g / min, 28 g of copolymerized polypropylene with a melt mass flow rate of 2 g / min, 28 g of linear low-density polyethylene with a density of 0.920 g / cm 316 g of polyolefin resin grafted inorganic thermal conductive filler and linear low density polyethylene.

[0062] Example 10 This example is basically the same as Example 8, except that this example provides a lining pipe material for oil and gas gathering and transportation pipelines, including 30 g of ethylene-vinyl alcohol random copolymer with a melt mass flow rate of 5 g / min, 30 g of copolymerized polypropylene with a melt mass flow rate of 2 g / min, 30 g of linear low density polyethylene with a density of 0.920 g / cm 3 and 10 g of polyolefin resin grafted inorganic thermal conductive filler.

[0063] Comparative Example 1 This comparative example provides a lining pipe material for oil and gas gathering and transportation pipelines, including 80 g of ethylene-vinyl alcohol random copolymer with a melt mass flow rate of 5 g / min and 20 g of graphene thermal conductive filler; Among them, the graphene was purchased from Zhongke Leiming (Beijing) Technology Co., Ltd., and the CAS number is 1034343-98-0.

[0064] This comparative example also provides a preparation method for the above-mentioned lining pipe for oil and gas gathering and transportation pipelines, including the following steps: Mix the ethylene-vinyl alcohol random copolymer and graphene thermal conductive filler according to the above ratio and then transport them to a single-screw extruder to extrude the pipe. The extrusion temperature is 200 °C.

[0065] Performance testing Testing standards: Heat distortion temperature (°C): ISO 75-1 Vicat softening point (°C): GB / T 1633 Tensile strength (Mpa): GB / T 1040-2006 Test the lining pipes for oil and gas gathering and transportation pipelines prepared in Examples 1-10 and Comparative Example 1, and the test results are shown in Table 2.

[0066] Table 1 Performance testing data of the lining pipes for oil and gas gathering and transportation pipelines in Examples 1-10 and Comparative Example 1

[0067] Referring to Table 1 and combining Examples 1 and Comparative Example 1, it can be seen that in this application, by adopting the physical irradiation grafting modification method and relying on the physical action of high-energy rays, the grafting of polyolefin on the inorganic thermal conductive filler is realized. This not only improves the heat resistance of the material, but also overcomes the problems of agglomeration of inorganic fillers and poor compatibility with the polymer matrix, improves the dispersion uniformity of inorganic fillers in the polymer matrix, and further improves the high-temperature resistance of the prepared polyolefin pipes.

[0068] Referring to Table 1 and combining Examples 1 and 2, it can be seen that in this application, by loading nano-spherical alumina on graphene, graphene not only has excellent thermal conductivity but also good adsorption properties. It has internal porous channels, a large specific surface area, and a three-dimensional wrinkled structure with undulating surfaces like waves, which can stably load nano-alumina, realizing the composite of nano-alumina and graphene. This not only does not reduce the thermal conductivity of nano-alumina but also avoids the agglomeration between nano-alumina particles, improving the high-temperature resistance of the material.

[0069] Referring to Table 1 and combining Examples 2 and 3, it can be seen that in this application, graphene is prepared by ultrasonic exfoliation of expanded graphite as a thermal conductive filler and grafted onto polyolefin resin. On the one hand, after the graphite expands, the internal pore channels increase and the adsorption performance is better, further improving the loading rate of nano-alumina on graphene. On the other hand, the graphene after ultrasonic treatment not only makes the expanded graphite quickly exfoliate to form graphene but also further increases the interlayer spacing of graphene, which is more conducive to the loading of nano-alumina, further improving the high-temperature resistance of the prepared polyolefin pipe.

[0070] Referring to Table 1 and combining Examples 7 and 8, it can be seen that in this application, nano-spherical alumina with different particle sizes is loaded on inorganic thermal conductive fillers, which can be filled in different pore sizes of graphene, further improving the loading rate of nano-alumina on graphene and further improving the high-temperature resistance of the prepared polyolefin pipe.

[0071] This specific embodiment is only an explanation of this application and does not limit this application. After reading this specification, those skilled in the art can make modifications without creative contributions to this embodiment as needed, but as long as it is within the scope of the claims of this application, it is protected by the patent law.

Claims

1. An inner lining pipe material for oil and gas gathering and transportation pipelines, characterized in that, It comprises 78 - 90 parts by weight of polyolefin resin and 10 - 22 parts by weight of polyolefin resin grafted with inorganic heat-conducting filler; the polyolefin resin grafted with inorganic heat-conducting filler is prepared by an irradiation cross-linking technique from polyolefin resin and inorganic heat-conducting filler.

2. The lining pipe material for oil and gas gathering and transportation pipelines according to claim 1, characterized in that The inorganic heat-conducting filler is graphene-supported nano-aluminum oxide.

3. The lining pipe material for oil and gas gathering and transportation pipelines according to claim 2, characterized in that, The preparation method of the polyolefin grafted with inorganic heat-conducting filler comprises the following steps: (1) Mix 1 part by weight of graphene with 10 - 100 parts by weight of deionized water, then add 0.01 - 0.05 part by weight of vinyl silane coupling agent, and subject to ultrasonic treatment to obtain a graphene dispersion; (2) Mix 1 part by weight of nano-aluminum oxide with (10 - 50) parts by weight of ethanol to obtain a nano-aluminum oxide dispersion, mix the graphene dispersion and the nano-aluminum oxide dispersion, subject to ultrasonic treatment and then dry to obtain vinyl silane-modified graphene-supported nano-aluminum oxide; (3) Mix 1 part by weight of vinyl silane-modified graphene-supported nano-aluminum oxide with 0.001 - 0.01 part by weight of cross-linking agent to obtain a mixed filler, then add 0.1 - 0.3 part by weight of polyolefin resin and melt-mix to obtain a resin mixed filler, and subject to electron beam treatment with a radiation energy of 1 - 5 MeV and a radiation beam current of 5 - 50 mA to obtain the polyolefin grafted with inorganic heat-conducting filler.

4. The lining pipe material for oil and gas gathering and transportation pipelines according to claim 3, characterized in that The preparation method of the graphene is as follows: subject graphite to acidification treatment and then high-temperature expansion to obtain expanded graphite, place the expanded graphite in an ethanol solution, and subject to ultrasonic treatment to obtain graphene.

5. The lining pipe material for oil and gas gathering and transportation pipelines according to claim 4, characterized in that, The preparation method of the expanded graphite is: react graphite with concentrated sulfuric acid, ammonium persulfate and a treatment solution containing hydrogen peroxide.

6. The lining pipe material for oil and gas gathering and transportation pipelines according to claim 3, characterized in that, The nano-aluminum oxide is a mixture of nano-spherical aluminum oxide with an average particle size of 5 - 10 nm and nano-spherical aluminum oxide with an average particle size of 20 - 50 nm in a mass ratio of (5 - 7):(3 - 5).

7. The lining pipe material for oil and gas gathering and transportation pipelines according to claim 3, characterized in that, The vinyl silane coupling agent is one or more of vinyltrimethoxysilane, vinyltriethoxysilane, vinyltris(β-methoxyethoxy)silane, vinyltri-tert-butoxysilane, vinyltri-tert-butylperoxysilane and vinyltriacetoxysilane.

8. The lining pipe material for oil and gas gathering and transportation pipelines according to claim 1, characterized in that, The polyolefin resin is one or more of ethylene-vinyl alcohol random copolymer, polyethylene, polypropylene and polyolefin elastomer.

9. A preparation method of a lined pipe for an oil and gas gathering and transportation pipeline, characterized in that, It is prepared by extrusion molding of the inner liner tube material, and the inner liner tube material is the inner liner tube material for oil and gas gathering and transportation pipelines described in any one of claims 1 - 8.

10. An oil and gas gathering and transportation pipeline, characterized in that, It sequentially comprises an inner liner tube, a reinforcing tube and an outer tube from the inside to the outside, and the inner liner tube is the inner liner tube for oil and gas gathering and transportation pipelines described in claim 9.

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