Large-diameter high-pressure hydrogen transmission pipeline with double-layer metal pipe resin lining and manufacturing method thereof

Abstract

The application discloses a double-layer metal pipe resin lining large-diameter high-pressure hydrogen conveying pipe, which comprises an outer metal pipe, an inner metal pipe, a plurality of centering bolts and a resin lining pipe, the inner metal pipe is arranged in the outer metal pipe, an annular space is formed between the outer metal pipe and the inner metal pipe, the inner wall of the inner metal pipe is coated with a sand glue coating, the outer metal pipe and the inner metal pipe are coaxially adjusted through the plurality of centering bolts, the centering bolts pass through the pipe wall of the inner metal pipe, the annular space in sequence and are in contact with the inner wall of the outer metal pipe, a gas guide channel is formed in the centering bolt, one end of the gas guide channel is connected with the sand glue coating of the inner wall of the inner metal pipe, the other end of the gas guide channel is connected with the annular space, the resin lining pipe is fixedly arranged in the inner hole of the inner metal pipe, and a lining pipe installation gap is formed between the resin lining pipe and the inner metal pipe. The application can avoid hydrogen embrittlement of the metal pipe. The application further discloses a manufacturing method of the double-layer metal pipe resin lining large-diameter high-pressure hydrogen conveying pipe.

Description

Technical Field

[0001] The present invention relates to a hydrogen transmission pipeline, and more particularly to a large-diameter high-pressure hydrogen transmission pipeline with a resin lining in a double-layer metal pipe. The present invention also relates to a manufacturing method for a large-diameter high-pressure hydrogen transmission pipeline with a resin lining in a double-layer metal pipe. Background Art

[0002] High-pressure gaseous hydrogen transmission is the mainstream technical pursuit for long-distance and large-scale hydrogen transmission, and is the only way to reduce the cost of hydrogen transmission. Traditional single-layer metal pipe hydrogen transmission pipelines and composite pipe hydrogen transmission already exist commonly, however, they both have fatal technical defects, that is, they cannot transmit hydrogen at high pressure. Once the pressure exceeds 2.5 MPa, the metal pipe will face the threat of hydrogen embrittlement (<6.3 MPa, <DN508 mm, GB / T 34542 series special steel, latest national standard); while the composite pipe will face the permeation of hydrogen (TCP pipe, Thermoplastic Composite pipe, the diameter generally cannot exceed DN250 mm, if it exceeds, both manufacturing and transportation will be problematic).

[0003] Whether it is the hydrogen embrittlement risk of the metal pipe or the permeation risk of the composite pipe, both lead to insufficient long-term operation safety of the pipeline. The hydrogen transmission pressure cannot be increased, the economy of hydrogen transmission is greatly limited, and the popularization and application of hydrogen energy are inhibited. Summary of the Invention

[0004] The technical problem to be solved by the present invention is to provide a large-diameter high-pressure hydrogen transmission pipeline with a resin lining in a double-layer metal pipe, which can solve the problem of hydrogen embrittlement in the metal pipeline system.

[0005] To solve the above technical problem, the technical solution of the large-diameter high-pressure hydrogen transmission pipeline with a resin lining in a double-layer metal pipe of the present invention is as follows:

[0006] The system includes an outer metal tube 5, an inner metal tube 3, multiple centering bolts 6, and a resin liner 1. The inner metal tube 3 is disposed inside the outer metal tube 5. An annular space 4 is formed between the outer metal tube 5 and the inner metal tube 3, serving as a low-pressure hydrogen discharge channel. The inner wall of the inner metal tube 3 is coated with a sand-adhesive coating 2. The multiple centering bolts 6 are distributed circumferentially and axially along the outer metal tube 5 and the inner metal tube 3. The coaxiality of the outer metal tube 5 and the inner metal tube 3 is adjusted by the multiple centering bolts 6. Bolt 6 passes through the inner metal tube 3 and the annular space 4 in sequence, and contacts the inner wall of the outer metal tube 5; a gas guiding channel 61 is opened in the centering bolt 6, one end of the gas guiding channel 61 leads to the sand-coated coating 2 on the inner wall of the inner metal tube 3, and the other end of the gas guiding channel 61 leads to the annular space 4; the resin liner tube 1 is fixedly inserted into the inner hole of the inner metal tube 3; the inner cavity of the liner tube 1 serves as the main channel for high-pressure hydrogen transportation; a liner tube installation gap 11 is formed between the resin liner tube 1 and the inner metal tube 3.

[0007] In another embodiment, during the transportation of high-pressure hydrogen in the double-layer metal pipe resin-lined large-diameter high-pressure hydrogen pipeline, the inner liner 1 expands under the high pressure of the medium, and the outer wall of the inner liner 1 is tightly attached to the sand-resin coating 2 on the inner wall of the inner metal pipe 3; a trace amount of hydrogen permeates into the pipe wall of the inner liner 1, and after passing through the inner liner 1 to the sand-resin coating 2, it flows along the gas-guiding microchannel of the sand-resin coating 2; when the permeated hydrogen flows to the position of the centering bolt 6, the hydrogen reaches the annular space 4 along the gas-guiding channel 61 of the centering bolt 6, and discharges the leaked hydrogen.

[0008] In another embodiment, the sand-coated layer 2 includes an epoxy phenolic primer layer and a sand-coated layer.

[0009] In another embodiment, the outer metal tube 5 and the inner metal tube 3 are coaxially arranged; the coaxiality of the outer metal tube 5 and the inner metal tube 3 is adjusted by the centering bolt 6.

[0010] In another embodiment, the resin liner tube 1 is made of an elastic material.

[0011] In another embodiment, the plurality of centering bolts 6 are symmetrically distributed around the center on the inner metal tube 3.

[0012] In another embodiment, the inner metal tube 3 has a through hole in its wall, and a hydrogen-resistant metal threaded sleeve 7 is fixedly installed in the through hole; the centering bolt 6 and the hydrogen-resistant metal threaded sleeve 7 are fixedly connected by threads and thread sealant; the hydrogen-resistant metal threaded sleeve 7 and the inner metal tube 3 are fixedly connected by welding.

[0013] In another embodiment, the outer metal tube 5 is provided with an injection valve 41 and a pressure relief valve 42. The outlet of the injection valve 41 and the inlet of the pressure relief valve 42 are connected to the annular space 4, and the injection valve 41, the annular space 4 and the pressure relief valve 42 form a gas passage.

[0014] This invention also provides a method for manufacturing a large-diameter high-pressure hydrogen transmission pipeline with a double-layer metal pipe and resin lining, the technical solution of which includes the following steps:

[0015] The first step is to manufacture the outer metal tube 5 and the inner metal tube 3 respectively; to make bolt holes in the wall of the inner metal tube 3 and weld the metal threaded sleeve 7 into the bolt holes; then to form a sand-adhesive coating 2 on the inner wall of the inner metal tube 3.

[0016] In another embodiment, the method for forming the sand-adhesive coating 2 in the first step is as follows:

[0017] First, spray epoxy phenolic primer onto the inner wall of the inner metal tube 3;

[0018] When the epoxy phenolic primer is in a gel state, 20-40 mesh quartz sand is evenly sprinkled on the surface of the epoxy phenolic primer. The coverage of the quartz sand on the epoxy phenolic primer is 60%-80%, so that the quartz sand particles are semi-embedded in the epoxy phenolic primer layer.

[0019] After the epoxy phenolic primer has cured, the inner wall surface of the inner metal tube 3 is blown away to remove loose sand and form a microchannel for air conduction.

[0020] In another embodiment, the quartz sand is spread over an area 10 mm away from the bolt holes of the inner metal tube 3.

[0021] In another embodiment, fine quartz sand of 60-80 mesh is sprinkled within 10 mm of the bolt holes of the inner metal tube 3.

[0022] The second step is to adjust the coaxiality of the outer metal tube 5 and the inner metal tube 3 by using multiple centering bolts 6 to form an annular space 4; then, metal pads 8 are inserted into both ends of the annular space 4 and welded to fix them.

[0023] The third step is to manufacture a resin inner liner tube 1, the outer diameter of which is 6-10 mm smaller than the inner diameter of the inner metal tube 3; the resin inner liner tube 1 is introduced into the double-layer metal tube by a rotary feed method to obtain the double-layer metal tube resin-lined large-diameter high-pressure hydrogen transmission pipeline.

[0024] The technical effects that this invention can achieve are:

[0025] The core concept of this invention is to use the design idea of ​​"guiding" rather than "blocking" to avoid the accumulation of osmotic pressure of permeating hydrogen, thereby preventing hydrogen embrittlement in metal pipeline systems.

[0026] This invention utilizes the hydrogen embrittlement resistance of non-metallic pipes and the high pressure resistance of metal pipes, and cleverly combines the two by setting up a high-pressure channel and a low-pressure channel in the same pipeline. The high-pressure channel is used to transport hydrogen, and the low-pressure channel is used to dilute and collect the permeated hydrogen, thereby achieving the purpose of protecting and extending the service life of the metal pipe while transporting hydrogen.

[0027] The inner metal tube of this invention is dedicated to bearing pressure for hydrogen transport (i.e., the high pressure of the transported medium is entirely borne by the inner metal tube), while the outer metal tube is dedicated to protection. The inner and outer metal tubes are independent of each other, which can achieve complete functional decoupling, thereby realizing the functionally decoupled double-layer steel pipe resin-lined large-diameter high-pressure hydrogen transport pipeline technology.

[0028] The present invention provides a sand-gel coating with gas-guiding microchannels on the inner wall of the inner metal tube, which enables the rapid and uniform flow of hydrogen gas to the bolt hole, while also providing corrosion protection and a low-friction installation interface.

[0029] This invention utilizes the annulus formed by the outer and inner metal tubes to simultaneously achieve three functions: hydrogen permeation and gas conduction, online monitoring, and emergency nitrogen replacement. Furthermore, the suction and injection channels are separated to avoid pressure shocks.

[0030] This invention utilizes the direct contact between the inner liner and the conveying medium, which can fundamentally isolate the steel pipe from the high-pressure hydrogen gas, thereby avoiding the risk of hydrogen embrittlement.

[0031] This invention can both prevent hydrogen embrittlement in metal tubes and directly address and solve the leakage problem of transporting high-pressure hydrogen in non-metallic tubes.

[0032] This invention features controllable hydrogen permeation, monitorable safety, simple construction, and low total life-cycle cost. Attached Figure Description

[0033] Those skilled in the art will understand that the following description is merely illustrative of the principles of the invention, which can be applied in various ways to achieve many different alternative implementations. These descriptions are intended only to illustrate the general principles of the teachings of the invention and are not intended to limit the inventive concept disclosed herein.

[0034] Embodiments of the invention are illustrated in conjunction with the accompanying drawings, which are incorporated in and form part of this specification, and together with the foregoing general description and the following detailed description of the drawings, serve to explain the principles of the invention.

[0035] The present invention will be further described in detail below with reference to the accompanying drawings and specific embodiments:

[0036] Figure 1 This is a cross-sectional schematic diagram of the large-diameter high-pressure hydrogen transmission pipeline with a double-layer metal pipe and resin lining according to the present invention.

[0037] Figure 2yes Figure 1 A magnified view of a portion of the image;

[0038] Figure 3 This is a cross-sectional schematic diagram of the present invention;

[0039] Figure 4 yes Figure 3 A magnified view of a portion of the image;

[0040] Figure 5 This is a schematic diagram of the working state of the present invention.

[0041] Explanation of the reference numerals in the figure:

[0042] 1 is a resin-lined tube, 2 is a sand-coated layer.

[0043] 3 is the inner metal tube, and 4 is the annular space.

[0044] 5 is the outer metal tube, and 6 is the centering bolt.

[0045] 7 is a hydrogen-resistant metal threaded sleeve.

[0046] 11 is the liner installation clearance, and 61 is the air guide channel.

[0047] 20 is a negative pressure traveling pipe, and 30 is a high pressure traveling pipe.

[0048] 41 is the air injection valve, and 42 is the pressure relief valve. Detailed Implementation

[0049] To make the objectives, technical solutions, and advantages of the embodiments of the present invention clearer, the technical solutions of the embodiments of the present invention will be clearly and completely described below with reference to the accompanying drawings. Obviously, the described embodiments are only some, not all, of the embodiments of the present invention. Based on the described embodiments of the present invention, all other embodiments obtained by those skilled in the art without creative effort are within the scope of protection of the present invention. Unless otherwise defined, the technical or scientific terms used herein should have the ordinary meaning understood by those skilled in the art to which this invention pertains. The terms "first," "second," and similar words used herein do not indicate any order, quantity, or importance, but are merely used to distinguish different components. Words such as "comprising" mean that the element or object preceding the word covers the element or object listed after the word and its equivalents, but does not exclude other elements or objects. Terms such as "upper," "lower," "left," and "right" are only used to indicate relative positional relationships; when the absolute position of the described object changes, the relative positional relationship may also change accordingly.

[0050] like Figure 1 , Figure 2As shown, the double-layer metal tube resin-lined large-diameter high-pressure hydrogen transmission pipeline of the present invention includes an outer metal tube 5 and an inner metal tube 3. The inner metal tube 3 is disposed inside the outer metal tube 5, and the outer metal tube 5 and the inner metal tube 3 are coaxially arranged. An annular space 4 is formed between the outer metal tube 5 and the inner metal tube 3, and the annular space 4 serves as a low-pressure hydrogen discharge channel.

[0051] The outer metal tube 5 and the inner metal tube 3 are fixedly connected by metal spacers 8; the metal spacers 8 are set at both ends of the annular space 4, and the metal spacers 8 are welded and fixed to the inner metal tube 3 and the outer metal tube 5.

[0052] The inner wall of the inner metal tube 3 is coated with a sand-adhesive coating 2;

[0053] The inner hole of the inner metal tube 3 is fitted with a resin inner liner tube 1, and the inner cavity of the inner liner tube 1 serves as the main channel for hydrogen transport.

[0054] A liner installation gap 11 is formed between the inner metal tube 3 and the resin inner liner tube 1 to facilitate the installation of the resin inner liner tube 1 into the inner hole of the inner metal tube 3.

[0055] like Figure 3 , Figure 4 As shown, the centering bolt 6 passes through the inner metal tube 3 and the annular space 4 in sequence, and comes into contact with the inner wall of the outer metal tube 5; the centering bolt 6 can provide support for the outer metal tube 5.

[0056] A venting channel 61 is provided inside the centering bolt 6. One end of the venting channel 61 leads to the sand coating 2 on the inner wall of the inner metal tube 3, and the other end of the venting channel 61 leads to the annular space 4.

[0057] Preferably, a plurality of centering bolts 6 are symmetrically distributed around the center on the inner metal tube 3;

[0058] Preferably, a hydrogen-resistant metal sleeve 7 is provided in the bolt hole of the inner metal tube 3, and the metal sleeve 7 is welded and fixed to the inner metal tube 3.

[0059] As a specific embodiment, the material of the hydrogen-resistant metal threaded sleeve 7 can be selected as hydrogen-resistant 2205 double molybdenum steel or surface-treated alloy steel.

[0060] The present invention uses multiple centering bolts 6 distributed circumferentially to adjust the coaxiality of the outer metal tube 5 and the inner metal tube 3, ensuring that the outer metal tube 5 and the inner metal tube 3 are precisely coaxial.

[0061] The present invention provides a gas guiding channel 61 in the centering bolt 6 to guide the flow of permeated hydrogen; at the same time, the unavoidable installation gap between the centering bolt 6 and the bolt hole can also serve as a gas guiding hole to guide the permeated hydrogen in a directional manner, without the need to open additional micropores, thereby ensuring the pressure resistance of the inner metal tube 3 to high-pressure media.

[0062] Therefore, the centering bolt 6 of the present invention has the dual functions of adjusting the coaxiality of the inner and outer tubes and guiding hydrogen flow.

[0063] As a specific embodiment, the nut of the centering bolt 6 is fixedly connected to the wall of the inner metal tube 3 by means of threads and thread-locking adhesive.

[0064] As a specific embodiment, the hydrogen transportation system is equipped with two accompanying pipes: a high-pressure accompanying pipe 30 for injecting protective gas and a negative-pressure accompanying pipe 20 for drawing in hydrogen gas leaking into the annulus. The high-pressure accompanying pipe 30 and the negative-pressure accompanying pipe 20 are connected to the annular space 4 of the main pipeline to form a gas channel for gas guidance and monitoring. The annular space 4 maintains a pressure of 0.3MPa < P < 2.5MPa, forming a negative pressure relationship with the accompanying gas guiding pipes. The permeated hydrogen gas is continuously drawn out, and the hydrogen concentration, pressure, temperature, and flow rate are monitored online to reflect the pipeline sealing status in real time.

[0065] The high-pressure traveling pipe 30 and the negative-pressure traveling pipe 20 can be small-diameter composite continuous pipes with a diameter not exceeding 20 cm;

[0066] The gas passage is equipped with an injection valve 41 and a pressure relief valve 42.

[0067] Emergency replacement: In case of leakage or maintenance, open the gas injection valve 41 to inject high-pressure nitrogen into the annular space 4 (the negative pressure gas inlet will automatically close), which will quickly dilute and replace the hydrogen in the annular space to achieve safe disposal.

[0068] Segmented isolation: Every 500-1000m, an annular segmented sealing structure is set up using pipeline connection nodes to achieve segmented monitoring and segmented risk control.

[0069] The resin liner tube 1 is made of an elastic material, such as modified PE (polyethylene), a mixture of HDPE (high-density polyethylene) and elastomers, Pa-12 (polydodecanoic acid), or other thermoplastics. The inner cavity of the resin liner tube 1 serves as a hydrogen transport channel.

[0070] This invention employs an elastic resin-lined tube 1. On one hand, this allows the tube 1 to directly contact hydrogen gas, preventing hydrogen embrittlement of the metal tube. On the other hand, this invention directly addresses the unavoidable permeation phenomenon of the resin-lined tube 1. During the transport of high-pressure hydrogen gas, a small amount of hydrogen gas permeates into the wall of the tube 1. After passing through the tube 1 and reaching the sand-coated coating 2, the permeated hydrogen gas flows along the microchannels of the sand-coated coating 2. When the permeated hydrogen gas reaches the position of the centering bolt 6, it flows along the gas channel 61 of the centering bolt 6 to the annular space 4, thereby discharging the leaked hydrogen gas. Since the medium in the annular space 4 is the leaked hydrogen gas, the hydrogen gas pressure is in a low-pressure zone not exceeding 2.5 MPa.

[0071] Therefore, this invention can solve both the hydrogen embrittlement problem of metal pipes and the leakage problem of non-metal pipes, thereby enabling long-distance transportation of high-pressure hydrogen.

[0072] Because the inner liner 1 of this invention is elastic, during the process of transporting high-pressure hydrogen, the inner liner 1 will expand under the high pressure of the medium in the tube, causing the outer wall of the inner liner 1 to adhere tightly to the inner wall of the inner metal tube 3, such as... Figure 5 As shown, this allows the inner metal tube 3 to withstand the pressure of the medium inside the tube. At the same time, hydrogen gas leaking from the inner liner tube 1 can directly enter the sand-coated layer 2 of the inner metal tube 3.

[0073] Preferably, the two ends of the resin inner liner tube 1 are formed with flanges, and the flanges of the resin inner liner tube 1 wrap around the end face of the inner metal tube 3 to form a seal.

[0074] The outer metal tube 5 and the inner metal tube 3 can be made of steel pipe;

[0075] As a specific embodiment, the wall thickness of the resin liner tube 1 is 10-20 mm.

[0076] The outer metal tube 5 has a wall thickness of 10-15mm and bears external loads (earth pressure, water pressure, ground load) as well as external protection.

[0077] The inner metal tube 3 has a wall thickness of 20-35 mm and independently bears the functions of hydrogen transport internal pressure and gas conduction.

[0078] The sand-coated layer 2 can be made by spraying an anti-hydrogen permeation epoxy phenolic primer layer and a sand-coated layer, with the sand-coated layer forming microchannels; the thickness is 0.3-0.5mm.

[0079] The present invention has a sand-gel coating 2 with gas guiding microchannels coated on the inner wall of the inner metal tube 3, which can form a continuous and stable hydrogen permeation guiding channel, ensuring that the permeated hydrogen gas flows quickly to the bolt hole and avoids local accumulation.

[0080] The annular space 4 has a gap of 20-30 mm and is kept at low pressure. It is used to collect permeated hydrogen, monitor it, and replace it with nitrogen in emergencies.

[0081] The liner installation gap 11 is 3-5mm, which realizes flexible isolation between the inner metal tube 3 and the inner liner tube 1, allowing the inner liner tube 1 to slide freely relative to the inner metal tube 3 to compensate for thermal expansion, so as to facilitate installation and eliminate thermal stress.

[0082] The wall thickness of the resin-lined tube 1 is 10-20 mm.

[0083] As a specific embodiment, the material of the centering bolt 6 can be selected as hydrogen embrittlement resistant 2205 double molybdenum steel or surface-treated alloy steel; the bolt hole edge is subjected to stress relief treatment (such as roll strengthening).

[0084] In this invention, a resin liner 1 is inserted through the inner hole of the inner metal tube 3, which independently undertakes the function of hydrogen transportation. The liner 1 prevents hydrogen from directly contacting the inner metal tube 3, thereby preventing hydrogen embrittlement of the metal tube.

[0085] This invention involves coating the inner wall of the inner metal tube 3 with a sand-like adhesive coating 2. Because this coating 2 is made of a porous material, it increases the flowability of hydrogen, guiding the hydrogen permeated from the inner liner tube 1, which is in direct contact with the hydrogen, into the annular space 4. Although the hydrogen in the annular space 4 still comes into direct contact with the outer metal tube 5 and the inner metal tube 3, the hydrogen in the annular space 4 is leaked low-pressure hydrogen, thus preventing hydrogen embrittlement of the outer metal tube 5 and the inner metal tube 3. Therefore, this invention solves the problem of hydrogen embrittlement in the transportation of high-pressure hydrogen through metal tubes.

[0086] This invention can be buried underground or placed on the ground.

[0087] The present invention discloses a method for manufacturing a large-diameter, high-pressure hydrogen transmission pipeline with a double-layer metal pipe and resin lining, comprising the following steps:

[0088] The first step is to fabricate the outer metal tube 5 and the inner metal tube 3 respectively, and to make bolt holes in the tube wall of the inner metal tube 3, and to weld the hydrogen-resistant metal threaded sleeve 7 into the bolt holes; then, to form a sand-adhesive coating 2 on the inner wall of the inner metal tube 3.

[0089] Specifically, first spray an anti-hydrogen permeation epoxy phenolic primer layer onto the inner wall of the inner metal tube 3;

[0090] When the epoxy phenolic primer layer is in a gel state, 20-40 mesh rounded quartz sand is evenly sprinkled on the surface of the epoxy phenolic primer layer. The coverage rate of the quartz sand on the epoxy phenolic primer layer is 60%-80%, so that the quartz sand particles are semi-embedded in the epoxy phenolic primer layer.

[0091] After the epoxy phenolic primer layer has cured, the inner wall surface of the inner metal tube 3 is blown away to remove loose sand, forming a rough but firm air-guiding microchannel.

[0092] Preferably, no sand or 60-80 mesh fine sand is applied within 10 mm around the bolt hole of the inner metal tube 3 to ensure that hydrogen can smoothly enter the bolt hole.

[0093] The sand-coated coating 2 formed by the present invention has a gas-guiding microchannel, which can ensure that the permeated hydrogen flows smoothly to the gas-guiding channel 61 of the centering bolt 6 and the gap between the centering bolt 6 and the bolt hole, so that the hydrogen permeated by the resin liner tube 1 can be discharged smoothly, so as to ensure the continuous long-distance transportation of high-pressure hydrogen.

[0094] The second step involves adjusting the coaxiality of the outer metal tube 5 and the inner metal tube 3 using multiple centering bolts 6 to form an annular space 4. The centering bolts 6 and the hydrogen-resistant metal sleeves 7 are then fixed together by threads and adhesive bonding. Metal pads 8 are then inserted into both ends of the annular space 4, and the outer metal tube 5 and the inner metal tube 3 are welded together using the metal pads 8 to obtain a double-layer metal tube section with a length of 12 meters.

[0095] The third step is to weld and fix multiple double-layer metal pipe sections in sequence to form a double-layer metal pipe, with each double-layer metal pipe section being 60 meters long; then, each double-layer metal pipe section is equipped with a set of air injection valve 41 and pressure relief valve 42; subsequently, the air injection valve 41 and pressure relief valve 42 are connected to the high and low pressure accompanying pipes.

[0096] The fourth step involves continuously extruding resin pipes using an extrusion device. The outer diameter of the resin pipe is 6-10 mm smaller than the inner diameter of the inner metal pipe 3. The pipe is then cut to a length of 60 m to obtain the resin inner liner pipe 1. The resin inner liner pipe 1 is then fed into the double-layer metal pipe using a rotary feed method to obtain a double-layer metal pipe resin-lined large-diameter high-pressure hydrogen transmission pipeline.

[0097] The present invention uses a rotary feeding method to guide the resin inner liner tube 1 into the inner metal tube 3; since the outer diameter of the resin inner liner tube 1 is 6 to 10 mm smaller than the inner diameter of the inner metal tube 3, a flexible sliding connection between the resin inner liner tube 1 and the inner metal tube 3 can be achieved, eliminating thermal expansion stress.

[0098] This invention is applicable to large-diameter, long-distance, high-pressure hydrogen transportation, with pipe diameters up to 800 mm and medium pressures not less than 0.3 MPa;

[0099] Preferably, the present invention can be used to transport hydrogen gas at a pressure not exceeding 10.0 MPa.

[0100] Obviously, those skilled in the art can make various modifications and variations to this invention without departing from its spirit and scope. Therefore, if these modifications fall within the scope of the claims of this invention and their equivalents, this invention also intends to include these modifications and variations.

Claims

1. A large-diameter, high-pressure hydrogen transmission pipeline with a double-layer metal pipe and resin lining, characterized in that, include: Outer metal tube, An inner metal tube is disposed inside the outer metal tube; An annular space is formed between the outer metal tube and the inner metal tube, which serves as a low-pressure hydrogen discharge channel; the inner wall of the inner metal tube is coated with a sand-adhesive coating. Multiple centering bolts are distributed circumferentially and axially along the outer and inner metal tubes; the coaxiality of the outer and inner metal tubes is adjusted by the multiple centering bolts; the centering bolts sequentially pass through the wall of the inner metal tube, the annular space, and contact the inner wall of the outer metal tube; each centering bolt has an air guide channel, one end of which leads to the sand-adhesive coating on the inner wall of the inner metal tube, and the other end of which leads to the annular space; and A resin liner tube is fixedly inserted into the inner hole of the inner metal tube; the inner cavity of the liner tube serves as the main channel for high-pressure hydrogen transportation; a liner tube installation gap is formed between the resin liner tube and the inner metal tube.

2. The double-layer metal pipe with resin lining, large-diameter high-pressure hydrogen transmission pipeline according to claim 1, characterized in that, During the transportation of high-pressure hydrogen, the double-layer metal pipe resin-lined large-diameter high-pressure hydrogen pipeline expands under the high pressure of the medium, and the outer wall of the inner lining pipe is tightly attached to the sand-rubber coating on the inner wall of the inner metal pipe. A trace amount of hydrogen permeates into the wall of the inner liner tube. After passing through the inner liner tube and reaching the sand coating, the permeated hydrogen flows along the gas-conducting microchannels of the sand coating. When the permeated hydrogen flows to the position of the centering bolt, the hydrogen reaches the annular space along the gas-conducting channel of the centering bolt, thus expelling the leaked hydrogen.

3. The double-layer metal pipe with resin lining, large-diameter high-pressure hydrogen transmission pipeline according to claim 1, characterized in that, The sand-coated layer includes an epoxy phenolic primer layer and a sand-coated surface layer.

4. The double-layer metal pipe with resin lining, large-diameter high-pressure hydrogen transmission pipeline according to claim 1, characterized in that, The outer metal tube and the inner metal tube are coaxially arranged; the coaxiality of the outer metal tube and the inner metal tube is adjusted by the centering bolt.

5. The double-layer metal pipe with resin lining, large-diameter high-pressure hydrogen transmission pipeline according to claim 1, characterized in that, The resin liner tube is made of an elastic material.

6. The double-layer metal pipe with resin lining, large-diameter high-pressure hydrogen transmission pipeline according to claim 1, characterized in that, The plurality of centering bolts are symmetrically distributed around the center on the inner metal tube.

7. The double-layer metal pipe with resin lining, large-diameter high-pressure hydrogen transmission pipeline according to claim 1, characterized in that, The outer metal tube is equipped with an injection valve and a pressure relief valve. The outlet of the injection valve and the inlet of the pressure relief valve are connected to the annular space, and the injection valve, the annular space and the pressure relief valve form a gas passage.

8. A method for manufacturing a large-diameter, high-pressure hydrogen transmission pipeline with a double-layer metal pipe and resin lining, characterized in that, Includes the following steps: The first step is to manufacture the outer metal tube and the inner metal tube separately; to make bolt holes in the wall of the inner metal tube and weld the metal threaded sleeve into the bolt holes; then to form a sand-plastic coating on the inner wall of the inner metal tube. The second step involves adjusting the coaxiality of the outer and inner metal tubes using multiple centering bolts to form an annular space; then, metal pads are inserted into both ends of the annular space and welded in place. The third step is to manufacture a resin liner tube, the outer diameter of which is 6-10 mm smaller than the inner diameter of the inner metal tube. The resin liner tube is then introduced into the double-layer metal tube using a rotary feed method to obtain the double-layer metal tube resin-lined large-diameter high-pressure hydrogen transmission pipeline.

9. The method for manufacturing a large-diameter high-pressure hydrogen transmission pipeline with a double-layer metal pipe and resin lining according to claim 8, characterized in that, The method for forming the first step of the sand-adhesive coating is as follows: First, spray epoxy phenolic primer onto the inner wall of the inner metal tube; When the epoxy phenolic primer is in a gel state, 20-40 mesh quartz sand is evenly sprinkled on the surface of the epoxy phenolic primer. The coverage of the quartz sand on the epoxy phenolic primer is 60%-80%, so that the quartz sand particles are semi-embedded in the epoxy phenolic primer layer. After the epoxy phenolic primer has cured, the inner wall surface of the inner metal tube is blown away to remove loose sand and form a microchannel for air conduction.

10. The method for manufacturing a large-diameter high-pressure hydrogen transmission pipeline with a double-layer metal pipe and resin lining according to claim 8, characterized in that, The quartz sand is spread over an area 10 mm away from the bolt holes of the inner metal tube; or, fine quartz sand of 60 to 80 mesh is spread over an area within 10 mm of the bolt holes of the inner metal tube.

11. The method for manufacturing a large-diameter high-pressure hydrogen transmission pipeline with a double-layer metal pipe and resin lining according to claim 8, characterized in that, The metal insert is a hydrogen-resistant metal insert.

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