Spiral framework composite ultralow-temperature-resistant flexible pipeline comprising multiple inner and outer framework steel wires and structural design method of spiral framework composite ultralow-temperature-resistant flexible pipeline
The spiral skeleton composite structure design with multiple inner and outer skeleton steel wires solves the problem of insufficient toughness of traditional pipelines in extremely low temperature environments, and achieves better bending flexibility and sealing performance, making it suitable for LNG transportation from inland waterways to deep seas.
Patent Information
- Application Number
- CN202511733367.9
- Authority / Receiving Office
- CN · China
- Patent Type
- Applications(China)
- Current Assignee / Owner
- Filing Date
- 2025-11-24
- Publication Date
- 2026-01-20
AI Technical Summary
Traditional spiral skeleton composite ultra-low temperature resistant flexible pipes lack toughness in extremely low temperature environments, making it difficult to meet the requirements for large plastic deformation. They also lack bending flexibility and sealing performance, making them unsuitable for complex and harsh actual engineering environments.
The design employs a spiral skeleton composite structure with multiple inner and outer skeleton steel wires, including an inner skeleton layer, a sealing layer, an insulation layer, and an outer skeleton layer. It uses 316L stainless steel or carbon fiber materials. The inner and outer skeleton layers are spirally wound at an angle of 80~90 degrees. The insulation layer uses aerogel material, and the braided reinforcement layer uses carbon fiber material. The overall structure is corrugated to improve flexibility and sealing performance.
It significantly improves the bending flexibility and sealing performance of pipelines, enhances mechanical and thermal insulation properties, is suitable for complex and harsh engineering environments, reduces the risk of pipeline instability, and is suitable for LNG transportation from inland river basins to the deep sea.
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Figure CN121363669A_ABST
Abstract
Description
TECHNICAL FIELD
[0001] The present application relates to the technical field of cryogenic pipeline, in particular, especially relates to a spiral skeleton composite ultra-low temperature flexible pipeline containing a plurality of inner and outer skeleton steel wires. BACKGROUND
[0002] Liquefied natural gas (LNG) is mainly composed of methane, which is a green energy with broad development prospects. The volume of liquefied natural gas is about 1 / 625 of the volume of the same amount of gaseous natural gas, so it is more conducive to storage and transportation. The spiral skeleton composite ultra-low temperature flexible pipeline is the core supporting equipment in the liquefied natural gas (LNG) transportation system, and is known as the "blood vessel" of the LNG system. It can be applied to the LNG filling of inland river basin, the transfer between ships, the floating LNG receiving station platform, and the floating liquefied natural gas production device system (FLNG).
[0003] At present, the "oil to gas" industry of ships in the inland river basin in China is developing rapidly, and the power fuel is gradually changed from gasoline to liquefied natural gas. As the core supporting equipment of the ship filling system in the inland river basin, the spiral skeleton composite ultra-low temperature flexible pipeline has good flexibility and adaptability in filling mode, which can reduce the influence caused by excessive movement between ships, bad sea conditions, and ship collision, and improve the safety performance of the whole filling system. It has a broad development prospect. Figure 1-2 A typical LNG filling and ship-to-ship transfer diagram in the inland river basin ship filling system.
[0004] In the floating LNG receiving station platform system, the spiral skeleton composite ultra-low temperature flexible pipeline is also the core supporting equipment. The floating LNG receiving station platform is a supplement and upgrade of the traditional LNG receiving station, which can realize the transmission of LNG between ships and shores without the help of traditional ports and wharfs, and can greatly reduce the investment cost and construction period. When the system is operating, the floating LNG receiving station platform approaches the LNG power ship until the floating platform and the ship are closely connected, and LNG is transported to the LNG power ship through the spiral skeleton composite ultra-low temperature flexible pipeline, as shown in Figure 3 .
[0005] Traditional deep sea development mode generally uses long distance subsea pipeline to exploit and transport oil and gas resources, however, the laying cost of rigid pipeline is often too high, and it is not easy to detect and maintain, once the pipeline is damaged, it will lead to major safety accidents or even serious ecological disasters. Therefore, for deep sea oil and gas fields or marginal oil and gas fields, a new development mode of full sea type, floating liquefied natural gas production device system (FLNG) is gradually applied, that is, a series of processes such as exploitation, processing, storage and transportation of oil and gas resources are completed on the sea, and the oil and gas resources are transported to the wharf by transport ship. The FLNG generally includes mooring system, production system, storage system, loading and unloading system and the like. Among them, the LNG loading and unloading system is one of the most important systems in the FLNG, mainly including two connection modes of side-by-side and tandem, as shown in Figure 4 and Figure 5 The spiral skeleton composite ultra-low temperature flexible pipe is a key supporting equipment for transporting liquefied natural gas in the LNG loading and unloading system.
[0006] In addition to the above application background, the spiral skeleton composite ultra-low temperature flexible pipe can also meet the transmission between land and sea and between land and land. In the actual process of transporting LNG, the working environment is often complex and harsh, and will be subjected to random loads such as wind, wave and current, and composite loads such as tension, bending and torsion, so the spiral skeleton composite ultra-low temperature flexible pipe needs to have good bending flexibility and sufficient safety.
[0007] The research and development of traditional LNG flexible pipe for external transmission began to rise in the early 21st century and developed rapidly, and its typical structure is generally a metal bellows as shown in Figure 6 However, the inner liner bellows of this structure is generally made of metal material, which is not ductile at-163℃, and the brittle metal material cannot meet the requirement of large plastic deformation in the ultra-low temperature working environment. The overall bending flexibility of the pipe is difficult to guarantee, and it is difficult to apply to harsh actual engineering environment. Therefore, a LNG low temperature flexible pipe with better bending flexibility, more excellent sealing performance, more stable mechanical properties and more reliable safety performance is needed. SUMMARY
[0008] According to the above technical problems, a spiral skeleton composite ultra-low temperature flexible pipe containing a plurality of inner and outer skeleton steel wires and a structure design method thereof are provided. The spiral skeleton composite ultra-low temperature flexible pipe containing a plurality of inner and outer skeleton steel wires greatly improves the bending flexibility of the traditional LNG flexible pipe for external transmission, and has more excellent sealing performance and thermal insulation performance.
[0009] The technical means adopted by the present application are as follows: A spiral skeleton composite ultra-low temperature resistant flexible pipe containing a plurality of inner and outer skeleton steel wires, which is corrugated as a whole, comprises: from inside to outside, an inner skeleton layer, a sealing layer, a heat preservation layer I, a heat preservation layer II, a braided reinforcing layer and an outer skeleton layer, the sealing layer is tightly wrapped on the outer circumferential surface of the inner skeleton layer, the heat preservation layer I is tightly wrapped on the outer circumferential surface of the sealing layer, the heat preservation layer II is tightly wrapped on the outer circumferential surface of the heat preservation layer I, the braided reinforcing layer is tightly wrapped on the outer circumferential surface of the heat preservation layer II, and the outer skeleton layer is tightly wrapped on the outer circumferential surface of the braided reinforcing layer; the inner skeleton layer comprises a plurality of first steel wires, the outer skeleton layer comprises a plurality of second steel wires, and the sealing layer, the heat preservation layer I, the heat preservation layer II and the braided reinforcing layer are all thin film structures.
[0010] Further, the inner skeleton layer is a skeleton structure formed by spiral winding of 3 or 4 uniformly arranged first steel wires, the spiral winding angle is 80-90 degrees, and the axial distance of each first steel wire is 1 / 3 of the pitch length or 1 / 4 of the pitch length.
[0011] Further, the sealing layer adopts fluorine-based material and is wound on the outer circumferential surface of the inner skeleton layer at a certain angle.
[0012] Further, the winding angle of the sealing layer is 40-50 degrees, and the thickness of the sealing layer is 5-10 mm.
[0013] Further, the heat preservation layer I and the heat preservation layer II are both aerogel materials with a thickness of 13-17 mm.
[0014] Further, the braided reinforcing layer is a mesh structure formed by close interlacing braiding of a plurality of carbon fiber materials in longitudinal and transverse directions, and the carbon fiber material is spiral braided; the thickness of the braided reinforcing layer is 5-10 mm.
[0015] Further, the outer skeleton layer is a skeleton structure formed by spiral winding of 3 or 4 uniformly arranged second steel wires, the spiral winding angle is 80-90 degrees, and the axial distance of each second steel wire is 1 / 3 of the pitch length or 1 / 4 of the pitch length.
[0016] Further, the first steel wire and the second steel wire adopt 316L stainless steel material or carbon fiber material.
[0017] The application also provides a structure design method of a spiral skeleton composite ultra-low temperature resistant flexible pipe containing a plurality of inner and outer skeleton steel wires, comprising the following steps: Step 1, determining a reasonable pipe structure form and selecting a suitable pipe inner diameter according to the actual engineering application background; Step 2, the structure size range of the inner and outer skeleton steel wires and the middle four-layer film structure is calculated according to the geometric relationship of the pipe section, so that the inner and outer skeleton steel wires and the middle film structure are closely matched, and the whole pipe presents a corrugated shape; the structure size range includes the geometric relationship of the inner and outer skeleton steel wire section diameter and the corrugated shape of the whole pipe, the structure parameters of the spiral angle and the pitch of the inner and outer skeleton steel wires, and the geometric parameters of the wave crest and the wave trough of the corrugated shape of the whole pipe; Step 3, according to the heat transfer principle and the heat balance equation, and based on the fact that the temperature inside the pipe is kept at-163 DEG C and the temperature of the outer wall of the pipe is kept at 0 DEG C, the heat preservation layer of the pipe is designed; Step 4, the overall performance of the pipe is analyzed according to the actual sea conditions of the engineering application background, the overall arrangement scheme of the pipe and the tension, bending and torsion working condition parameters are determined, and finally the structure design of each layer of the pipe is determined according to the comprehensive requirements of stiffness, strength and stability.
[0018] Compared with the prior art, the present application has the following advantages: 1, the spiral skeleton composite ultra-low temperature flexible pipe of the present application adopts a plurality of inner and outer skeleton steel wires as the inner and outer skeleton layers of the pipe, which are uniformly stressed at any position of the pipe cross section, so that the mechanical properties of the spiral skeleton composite ultra-low temperature flexible pipe cross section are more stable, and the more the inner and outer skeleton steel wires, the stronger the stability of the pipe.
[0019] 2, the ultra-low temperature working environment (-163 DEG C) inside the spiral skeleton composite ultra-low temperature flexible pipe is one of the design technical difficulties of liquefied natural gas transmission. The pipe heat preservation layer of the present application adopts aerogel material, and is designed to be thick enough (two layers of heat preservation layer, thickness is 15 mm) to keep the-163 DEG C ultra-low temperature environment inside the pipe and the 0 DEG C or above of the outer wall of the pipe, to prevent the liquefied natural gas inside the pipe from vaporizing or the outer wall of the pipe from icing, thereby affecting the mechanical properties of the pipe.
[0020] 3, in the actual application environment of transmitting liquefied natural gas, whether it is tandem, side-by-side, or filling, the bending flexibility requirement of the pipe is relatively high. The spiral skeleton composite ultra-low temperature flexible pipe of the present application uses inner and outer spiral skeleton steel wires to extrude the whole pipe into a corrugated shape, which can greatly improve the bending flexibility of the whole pipe, greatly reduce the bending radius of the pipe, and make the whole pipe structure more "flexible".
[0021] 4, the spiral skeleton composite ultra-low temperature flexible pipe provided by the present application, which contains a plurality of inner and outer skeleton steel wires, can be applied to the application background from inland filling, transshipment to deep sea floating liquefied natural gas production device system (FLNG), without limitation on the inner diameter size, and has a wide application range.
[0022] 5、The spiral skeleton composite ultra-low temperature flexible pipeline provided by the application contains multiple inner and outer skeleton steel wires, and in terms of material selection, non-metal composite materials are mainly used, and compared with the low temperature pipeline of the metal corrugated pipe type, the spiral skeleton composite ultra-low temperature flexible pipeline has better sealing performance and better bending flexibility.
[0023] 6、Compared with the low temperature pipeline with only a single inner and outer skeleton steel wire, the spiral skeleton composite ultra-low temperature flexible pipeline of the application uses multiple inner and outer skeleton steel wires as the inner and outer skeleton layers. If a certain inner and outer skeleton steel wire fails or breaks, the influence on the overall structure of the pipeline will not be too great to a certain extent, and the mechanical properties of the pipeline will be basically guaranteed in the short term. Therefore, the spiral skeleton composite ultra-low temperature flexible pipeline containing multiple inner and outer skeleton steel wires is more durable.
[0024] Based on the above reasons, the application can be widely promoted in the fields of LNG filling and ship-to-ship transfer in inland river basins, LNG receiving station platforms, and floating liquefied natural gas production device systems (FLNG). BRIEF DESCRIPTION OF DRAWINGS
[0025] In order to more clearly illustrate the technical solutions in the embodiments of the application or the prior art, the drawings needed to be used in the embodiments or the prior art description will be briefly introduced below. Obviously, the drawings in the following description are some embodiments of the application, and other drawings can also be obtained by those skilled in the art without creative labor.
[0026] Figure 1 It is a schematic diagram of LNG filling and ship-to-ship transfer in the prior art in the inland river basin.
[0027] Figure 2 It is a schematic diagram of ship-to-ship transfer in the prior art in the inland river basin.
[0028] Figure 3 It is a schematic diagram of a floating LNG receiving station platform system in the prior art.
[0029] Figure 4 It is a side-by-side connection mode of ship-to-ship transfer in the prior art.
[0030] Figure 5 It is a tandem connection mode of ship-to-ship transfer in the prior art.
[0031] Figure 6 It is a schematic diagram of the inner lining metal corrugated pipe structure of a traditional LNG low temperature flexible pipeline.
[0032] Figure 7 It is a schematic diagram of the overall structure of the spiral skeleton composite ultra-low temperature flexible pipeline containing three inner and outer skeleton steel wires of the application.
[0033] Figure 8 The whole structure diagram of the spiral skeleton composite ultra-low temperature resistant flexible pipe containing 4 inner and outer skeleton steel wires of the present application.
[0034] Figure 9 The inner skeleton layer schematic diagram of the spiral skeleton composite ultra-low temperature resistant flexible pipe containing 3 inner and outer skeleton steel wires of the present application.
[0035] Figure 10 The inner and outer skeleton layer whole schematic diagram of the spiral skeleton composite ultra-low temperature resistant flexible pipe containing 3 inner and outer skeleton steel wires of the present application.
[0036] Figure 11 The axial section view of the spiral skeleton composite ultra-low temperature resistant flexible pipe containing 3 inner and outer skeleton steel wires of the present application.
[0037] Figure 12 The axial section view enlarged diagram of the spiral skeleton composite ultra-low temperature resistant flexible pipe containing 3 inner and outer skeleton steel wires of the present application.
[0038] Figure 13 The radial section view of the spiral skeleton composite ultra-low temperature resistant flexible pipe containing 3 inner and outer skeleton steel wires of the present application.
[0039] Figure 14 The radial section view of the spiral skeleton composite ultra-low temperature resistant flexible pipe containing 4 inner and outer skeleton steel wires of the present application.
[0040] In the figure: 1, inner skeleton layer; 2, sealing layer; 3, heat preservation layer I; 4, heat preservation layer II; 5, braided reinforcing layer; 6, outer skeleton layer. DETAILED DESCRIPTION
[0041] It should be noted that the embodiments in the present application and the features in the embodiments can be combined with each other without conflict. The present application will be described in detail below with reference to the accompanying drawings and in combination with the embodiments.
[0042] In order to make the purpose, technical scheme and advantages of the embodiments of the present application clearer, the technical scheme in the embodiments of the present application will be described clearly and completely below in combination with the drawings of the embodiments of the present application. Obviously, the described embodiments are only part of the embodiments of the present application, not all the embodiments. The description of the at least one exemplary embodiment is actually only illustrative, not as any limitation on the present application and its application or use. Based on the embodiments in the present application, all other embodiments obtained by those skilled in the art without creative labor are within the scope of protection of the present application.
[0043] It is to be understood that the terms so far as the word "comprise" and / or "comprising", or "include" and / or "including" when used in this specification is / are used to express the inclusion of one or more steps, operations, elements, and / or components, but these articles do not exclude the other steps, operations, elements, and / or components.
[0044] The relative arrangement of parts and steps, numerical expressions, and numerical values set forth in the examples are not intended to limit the scope of the application unless specifically so stated. It is also to be understood that the dimensions of the various parts shown in the drawings are not drawn to scale for ease of illustration. Techniques, methods, and apparatus known to those of ordinary skill in the relevant art can not be discussed in detail, but should be considered part of the specification as appropriate. In all examples shown and discussed herein, any specific values are to be interpreted as illustrative only and not as a limitation. Thus, other examples of the exemplary embodiments can have different values. It is to be noted that like numbers and letters refer to like elements throughout the several views of the drawings and, as such, no further discussion with regard thereto is deemed necessary.
[0045] In the description of the present application, it is to be understood that the orientation or positional relationships indicated by orientation words such as "front, back, upper, lower, left, right", "transverse, vertical, perpendicular, horizontal", and "top, bottom" are generally based on the orientation or positional relationships shown in the drawings, and are only for the convenience of describing the present application and simplifying the description. Without the opposite indication, these orientation words do not indicate and imply that the devices or elements referred to must have a particular orientation or be constructed and operated in a particular orientation, and therefore cannot be understood as a limitation on the scope of protection of the present application: the orientation words "inner, outer" refer to the inner and outer relative to the contour of each component.
[0046] For the purposes of this description, spatially relative terms, such as "above", "below", "up", "down", "between", "within", "left", "right", "front", "back", "upper", "lower", "horizontal", "vertical", "above", "below", "up", "down", "top", "bottom", "side", "end", etc., are intended to describe the orientation of one device or feature relative to another device or feature as illustrated in the figures. The spatially relative terms are intended to encompass different orientations of the devices in use or operation in addition to the orientations depicted in the figures. The devices can be otherwise oriented (rotated 90 degrees or at other orientations) and the spatially relative descriptors used herein interpreted accordingly. For example, if a device is described as "above" or "up" another device or structure, it can be oriented "below" or "down" the other device or structure when placed in another orientation. Similarly, if a device is described as "between" two other devices or structures, it can be oriented "between", "above", or "below" the other devices or structures. Accordingly, the spatially relative terms used herein are intended to encompass all such orientations.
[0047] In addition, it should be noted that the use of "first", "second", and the like words of distinction do not necessarily imply a special meaning, but are merely used to identify different components, unless otherwise stated, and should not be construed as limiting the scope of protection of the present application.
[0048] Example 1 To meet the requirements of good bending flexibility and safety of the spiral skeleton composite ultra-low temperature flexible pipe in the process of transporting LNG, the present application provides a spiral skeleton composite ultra-low temperature flexible pipe containing a plurality of inner and outer skeleton steel wires, which is a new type of spiral skeleton composite ultra-low temperature flexible pipe for external transportation of low-temperature liquefied natural gas (LNG), and can be used for LNG filling in river basins, ship-to-ship transfer, LNG receiving station platforms, and floating liquefied natural gas production device systems (FLNG), etc., and is a core supporting equipment for transporting LNG. The present application greatly improves the bending flexibility of traditional external LNG low-temperature flexible pipes, and simultaneously has more excellent sealing performance and thermal insulation performance.
[0049] As shown in the accompanying drawings Figure 7 and the accompanying drawings Figure 8 The spiral skeleton composite ultra-low temperature flexible pipe containing a plurality of inner and outer skeleton steel wires of the present application mainly includes, from the inside to the outside, an inner skeleton layer 1, a sealing layer 2, a thermal insulation layer I 3, a thermal insulation layer II 4, a braided reinforcing layer 5, and an outer skeleton layer 6. The sealing layer 2 is tightly wrapped around the outer circumferential surface of the inner skeleton layer 1, the thermal insulation layer I 3 is tightly wrapped around the outer circumferential surface of the sealing layer 2, the thermal insulation layer II 4 is tightly wrapped around the outer circumferential surface of the thermal insulation layer I 3, the braided reinforcing layer 5 is tightly wrapped around the outer circumferential surface of the thermal insulation layer II 4, and the outer skeleton layer 6 is tightly wrapped around the outer circumferential surface of the braided reinforcing layer 5.
[0050] The inner skeleton layer 1 consists of 3 or 4 spirally wound steel wires arranged evenly in the shape of springs (setting the steel wires to 3 or 4 will make the structure more stable and the mechanical properties of the structure better). The spiral winding angle is 80~90 degrees (the spiral winding angle of 80-90 degrees can ensure the pipe has bending flexibility to meet the actual engineering needs). The axial distance of each spirally wound steel wire is 1 / 3 of the pitch length of each steel wire (3 spirally wound steel wires) or 1 / 4 of the pitch length (4 spirally wound steel wires). The axial distance is determined according to the geometric relationship, which allows the 3 or 4 steel wires to be evenly arranged.
[0051] The sealing layer 2 is made of polytetrafluoroethylene propylene and is wound around the inner skeleton layer 1 at a certain angle (40~50 degrees depending on the actual process, of which 45 degrees can ensure better sealing).
[0052] The insulation layer has a two-layer structure, with each layer being an aerogel material with a thickness of 13-17 mm.
[0053] The braided reinforcement layer 5 consists of multiple carbon fiber materials spirally woven into a twisted shape (the twisted structure can maintain better bending flexibility) and tightly interwoven longitudinally and laterally (which can enhance the load-bearing capacity of the pipe).
[0054] The outer skeleton layer 6 consists of 3 or 4 spirally wound steel wires arranged evenly in the shape of springs (the use of 3 or 4 steel wires makes the overall structure more stable and the mechanical properties of the structure better). The spiral winding angle is 80~90 degrees, and the axial distance of each spirally wound steel wire is 1 / 3 of the pitch length of each steel wire (3 spirally wound steel wires) or 1 / 4 of the pitch length (4 spirally wound steel wires). The axial distance is determined according to the geometric relationship, which allows the 3 or 4 steel wires to be evenly arranged.
[0055] Example 2 The overall structure of the spiral skeleton composite ultra-low temperature resistant flexible pipe of the present invention, which includes multiple inner and outer skeleton steel wires, is shown in the attached figure. Figure 7 and attached Figure 8 As shown, a structural example of a novel spiral-framed composite cryogenic flexible pipe is described. It consists of 3 (attached) Figure 5 ) or 4 sticks (with) Figure 6The three or four spring-shaped helically wound steel wires are uniformly arranged to form the first layer structure, the inner framework layer 1, of the spiral framework composite ultra-low-temperature-resistant flexible pipeline, and can adopt 316L stainless steel material or carbon fiber material. The second layer to the fifth layer are all film structures, and are tightly pressed and helically wound on the inner framework layer 1 in a certain angle according to the layer sequence. The second layer is the sealing layer 2, which plays a role of sealing the LNG in the pipeline, and can adopt polytetrafluoroethylene material. The third layer and the fourth layer are the heat preservation layers, which play a role of maintaining the internal temperature of the pipeline and isolating the heat transfer between the inside and outside of the pipeline, and can adopt aerogel material. The fifth layer is the woven reinforcing layer 5, which plays a role of enhancing the tensile property of the pipeline and providing axial stiffness, and can adopt carbon fiber material. The sixth layer is the outer framework layer 6, which is formed by three or four (the number is consistent with that of the inner framework layer 1) spring-shaped helically wound steel wires that are uniformly and tightly pressed and helically wound on the fifth layer film structure, and forms the outermost structure of the spiral framework composite ultra-low-temperature-resistant flexible pipeline. Similarly, the outer framework layer 6 can also adopt 316L stainless steel material or carbon fiber material.
[0056] The specific implementation is as follows: As the first layer structure, the inner framework layer 1 is formed by three (as shown in the attached Figure 7 ) or four (as shown in the attached Figure 8 ) spring-shaped helically wound steel wires, the helical winding angle is about 85 degrees, and the axial distance of each helically wound steel wire is 1 / 3 of the pitch length (for three helically wound steel wires) or 1 / 4 of the pitch length (for four helically wound steel wires), and the specific arrangement structure is shown in the attached Figure 9 The inner framework layer 1 provides radial stiffness for the spiral framework composite ultra-low-temperature-resistant flexible pipeline, supports the entire pipeline, and prevents crushing.
[0057] On the basis of the inner framework layer 1, the polytetrafluoroethylene material is wound on the outer circumferential surface of the inner framework layer 1 at a certain angle (about 45 degrees) to form the sealing layer 2 structure of the spiral framework composite ultra-low-temperature-resistant flexible pipeline, as shown in the attached Figure 7 and the attached Figure 8 The polytetrafluoroethylene material has good sealing performance, is not easy to chemically react with liquefied natural gas, has a large controllable temperature range for processing and molding, is convenient for processing and manufacturing, and the mechanical properties and physical properties can meet the requirements of the sealing layer of the spiral framework composite ultra-low-temperature-resistant flexible pipeline.
[0058] In order to prevent the vaporization of liquefied natural gas caused by the increase of the internal temperature of the pipeline, and also to prevent the freezing of the outer wall of the pipeline from affecting the mechanical properties of the pipeline, it is necessary to provide a heat preservation layer for the pipeline. The heat preservation layer of the spiral framework composite ultra-low-temperature-resistant flexible pipeline of the present application has a two-layer structure, including heat preservation layer I 3 and heat preservation layer II 4, two layers of aerogel material with a thickness of about 15 millimeters are laid outside the sealing layer 2 as the heat preservation layers, which play a role of heat preservation and cold insulation, as shown in the attached Figure 7 and the attachedFigure 8 as shown.
[0059] In order to enhance the tensile properties of the pipeline, improve the axial stiffness, the spiral skeleton composite ultra-low temperature flexible pipeline of the present application is provided with a woven reinforcing layer 5 outside the insulation layer II 4, which is mainly made of carbon fiber, as shown in the accompanying drawings. Figure 7 as shown in the accompanying drawings. Figure 8 The woven reinforcing structure is similar to a mesh, a plurality of carbon fiber materials are first woven into a floss structure, and then the mesh structure is formed by tightly interlaced weaving in the longitudinal and transverse directions, and the mesh structure is spirally wound outside the insulation layer II 4 to form the woven reinforcing layer 5 of the spiral skeleton composite ultra-low temperature flexible pipeline.
[0060] As the outermost structure, the outer skeleton layer 6 is uniformly arranged by 3 or 4 spiral wound steel wires in the shape of a spring (the number is consistent with that of the inner skeleton layer 1), the spiral winding angle is about 85 degrees, and the axial distance of each spiral wound steel wire is 1 / 3 of the pitch length (3 spiral wound steel wires) or 1 / 4 of the pitch length (4 spiral wound steel wires). The outer skeleton layer 6 can provide radial stiffness for the spiral skeleton composite ultra-low temperature flexible pipeline and resist sudden impact load. The mutual extrusion of the outer skeleton layer 6 and the inner skeleton layer 1 can make the entire pipeline present a corrugated shape, which not only improves the resistance to internal pressure of the spiral skeleton composite ultra-low temperature flexible pipeline, but also makes the pipeline as a whole have better bending flexibility. The overall arrangement structure of the inner and outer skeleton layers is shown in the accompanying drawings. Figure 10
[0061] as shown in the accompanying drawings. Figure 11 The axial cross-sectional view of the spiral skeleton composite ultra-low temperature flexible pipeline of the present application is shown in the accompanying drawings, which includes 3 or 4 inner and outer skeleton steel wires, from inside to outside, the inner skeleton layer 1, the sealing layer 2, the insulation layer I 3, the insulation layer II 4, the woven reinforcing layer 5, and the outer skeleton layer 6. The plurality of inner skeleton steel wires in the shape of a spring can be made of metal 316L stainless steel material or non-metal carbon fiber material, spirally wound at an angle of 85 degrees, and uniformly arranged by the same 3 or 4 skeleton steel wires, and the axial distance of each spiral wound steel wire is 1 / 3 of the pitch length (3 spiral wound steel wires) or 1 / 4 of the pitch length (4 spiral wound steel wires). Then the sealing layer 2, the two insulation layers, and the woven reinforcing layer 5 are spirally wound on the inner skeleton layer 1 in turn, and finally 3 or 4 outer skeleton steel wires are tightly extruded to make the pipeline as a whole present a corrugated shape. The inner skeleton layer 1 and the intermediate film layer and the outer skeleton layer 6 and the intermediate film layer can slide and stretch with each other.
[0062] as shown in the accompanying drawings. Figure 12 as shown in the accompanying drawings. Figure 11 The enlarged view shows that, from bottom (inside the pipe) to top (outside the pipe), the layers are: inner skeleton layer 1, sealing layer 2, insulation layer I 3, insulation layer II 4, braided reinforcement layer 5, and outer skeleton layer 6. The six structural layers of the pipe are closely arranged, and the whole structure presents a distinct corrugated shape, which greatly improves the bending flexibility of the spiral skeleton composite ultra-low temperature resistant flexible pipe of the present invention. The inner and outer skeleton layers can be made of metallic materials (such as 316L stainless steel) or non-metallic materials (such as carbon fiber) to support the entire pipe and provide radial stiffness. The sealing layer 2 can be made of fluorine-based materials, including PFA soluble polytetrafluoroethylene, FEP (F46) perfluoroethylene propylene, and PTFE (powder) polytetrafluoroethylene, with FEP (F46) perfluoroethylene propylene being the best material. The thickness can be 5-10 mm (8-16 inches inner diameter). The insulation layer I3 and insulation layer II4 can be made of aerogel materials, each with a thickness of 15 mm (at room temperature of 20°C, 8-16 inches inner diameter). The braided reinforcement layer 5 can be made of carbon fiber braided material, with an overall structure similar to a woven net. The braided carbon fiber material is woven longitudinally and laterally to form a mesh structure, and this mesh structure is spirally wound around the insulation layer II4. The thickness can be 5-10 mm (8-16 inches inner diameter).
[0063] Appendix Figure 13 and attached Figure 14 This is a radial cross-sectional view of the spiral skeleton composite ultra-low temperature resistant flexible pipe of the present invention. (According to the attached...) Figure 13 As can be seen from the pipe cross-section structure, when there are three inner and outer reinforcing steel wires, the three inner and outer reinforcing steel wires on the circumference of any position on the pipe cross-section are distributed at an angle of 120 degrees to each other and are subjected to uniform force; according to the attached... Figure 14 As can be seen from the pipe cross-section structure, when there are four inner and outer reinforcing steel wires, the four inner and outer reinforcing steel wires on the circumference of any position on the pipe cross-section are distributed at 90-degree angles to each other, and are also uniformly stressed. Therefore, pipe cross-sections with three or four inner and outer reinforcing steel wires exhibit more stable mechanical properties and are less prone to instability; the more inner and outer reinforcing steel wires, the stronger the pipe's stability. Furthermore, spiral-reinforced composite cryogenic flexible pipes containing multiple inner and outer reinforcing steel wires also possess stronger axial and radial stiffness, better internal pressure resistance, and improved bending flexibility, significantly enhancing the overall mechanical properties of the spiral-reinforced composite cryogenic flexible pipe.
[0064] This invention also provides a structural design method for a spiral skeleton composite ultra-low temperature resistant flexible pipe containing multiple inner and outer skeleton steel wires, taking into account factors such as application background, geometric relationship, thermal performance, and mechanical performance. The method includes the following steps: (1) According to the actual engineering background of liquefied natural gas transportation, the application environment of the spiral skeleton composite ultra-low temperature flexible pipe can be divided into the following three types: the first is the LNG filling and ship-to-ship transfer in the inland river basin, which can generally select a small diameter low temperature pipe. The second is the LNG receiving station platform, which can generally select a medium diameter low temperature pipe. The third is the exploitation of deep sea oil and gas resources, i.e. the floating liquefied natural gas production system (FLNG), which can generally select a large diameter low temperature pipe. When designing the structure of the spiral skeleton composite ultra-low temperature flexible pipe, the reasonable pipe structure form can be determined according to the actual engineering application background, and the appropriate pipe diameter can be selected; (2) In order to make the inner and outer skeleton steel wires and the intermediate film structure of the pipe better match, and make the spiral skeleton composite ultra-low temperature flexible pipe as a whole present a corrugated shape, the structure size range of the inner and outer skeleton steel wires and the intermediate film can be calculated according to the geometric relationship of the pipe cross section, including the geometric relationship of the pipe overall corrugated shape and the inner and outer skeleton steel wire cross section diameter, the structure parameters of the inner and outer skeleton steel wire spiral angle and pitch, and the geometric parameters of the pipe overall corrugated shape wave crest and wave trough. The local structure is shown in FIG. 1, and the above geometric relationship needs to be met in the subsequent structure design of the spiral skeleton composite ultra-low temperature flexible pipe; Figure 12 (3) One of the technical difficulties of the spiral skeleton composite ultra-low temperature flexible pipe is to maintain the ultra-low temperature environment inside the pipe while preventing the pipe outer wall from icing, so as to avoid affecting the mechanical properties of the overall pipe structure. Therefore, according to the heat transfer principle and heat balance equation, the pipe internal temperature is maintained at -163℃ and the pipe outer wall is above 0℃ as the target, the insulation layer design of the spiral skeleton composite ultra-low temperature flexible pipe is completed; (4) In addition, when designing the detailed structure of the spiral skeleton composite ultra-low temperature flexible pipe, the overall performance of the pipe needs to be analyzed according to the actual sea conditions of the engineering application background, the overall layout scheme of the pipe and the specific working condition parameters such as tension, bending and torsion are determined, and the structure design of each layer of the spiral skeleton composite ultra-low temperature flexible pipe is finally determined according to the comprehensive requirements of stiffness, strength and stability. Among them, in order to make the pipe have better bending flexibility, the pipe overall structure presents a corrugated geometric structure form; in order to make the pipe cross section force more uniform and the structure more stable, multiple inner and outer skeleton steel wires are used as the inner and outer skeleton layers of the spiral skeleton composite ultra-low temperature flexible pipe.
[0065] It should be noted that the above embodiments are only used to illustrate the technical solutions of the present application, and are not intended to limit the present application; although the present application has been described in detail with reference to the above embodiments, those skilled in the art should understand that the technical solutions recorded in the above embodiments can be modified, or some or all of the technical features can be replaced by equivalents; and these modifications or replacements do not make the essence of the corresponding technical solutions deviate from the scope of the technical solutions of the embodiments of the present application.
Claims
1. A spiral-wound composite ultra-low temperature flexible pipe comprising a plurality of inner and outer carcass steel wires, characterised in that, The overall structure is corrugated and includes: an inner skeleton layer (1), a sealing layer (2), a heat insulation layer I (3), a heat insulation layer II (4), a braided reinforcement layer (5), and an outer skeleton layer (6) arranged coaxially from the inside to the outside. The sealing layer (2) is tightly wrapped around the outer circumference of the inner skeleton layer (1), the heat insulation layer I (3) is tightly wrapped around the outer circumference of the sealing layer (2), the heat insulation layer II (4) is tightly wrapped around the outer circumference of the heat insulation layer I (3), the braided reinforcement layer (5) is tightly wrapped around the outer circumference of the heat insulation layer II (4), and the outer skeleton layer (6) is tightly wrapped around the outer circumference of the braided reinforcement layer (5). The inner skeleton layer (1) includes multiple first steel wires, and the outer skeleton layer (6) includes multiple second steel wires. The sealing layer (2), the heat insulation layer I (3), the heat insulation layer II (4), and the braided reinforcement layer (5) are all thin film structures.
2. The spiral-wound composite ultra-low temperature flexible pipe containing a plurality of inner and outer carcass steel wires of claim 1 characterised in that, The inner skeleton layer (1) is a skeleton structure formed by spirally winding 3 or 4 evenly arranged first steel wires, with a spiral winding angle of 80 to 90 degrees, and the axial distance of each first steel wire is 1 / 3 of the pitch length or 1 / 4 of the pitch length.
3. The spiral-wound composite ultra-low temperature flexible pipe including a plurality of inner and outer carcass steel wires as defined in claim 1, characterized in that, The sealing layer (2) is made of fluorine-based material and is wrapped around the outer circumference of the inner skeleton layer (1) at a certain angle.
4. The spiral-wound composite ultra-low temperature flexible pipe including a plurality of inner and outer carcass steel wires of claim 3, characterized in that, The winding angle of the sealing layer (2) is 40~50 degrees, and the thickness of the sealing layer (2) is 5~10 mm.
5. The spiral-wound composite ultra-low temperature flexible pipe including a plurality of inner and outer carcass steel wires as defined in claim 1, characterized in that, Both the insulation layer I (3) and the insulation layer II (4) are aerogel materials with a thickness of 13~17 mm.
6. The spiral-wound composite ultra-low temperature flexible pipe comprising a plurality of inner and outer carcass steel wires according to claim 1, characterized in that, The braided reinforcement layer (5) is a mesh structure formed by the longitudinal and transverse tight interlacing of the braided structure, which is made of multiple carbon fiber materials spirally woven together; the thickness of the braided reinforcement layer (5) is 5~10 mm.
7. The spiral-wound composite ultra-low temperature flexible pipe including a plurality of inner and outer carcass steel wires of claim 1, characterized in that, The outer skeleton layer (6) is a skeleton structure formed by spirally winding 3 or 4 evenly arranged second steel wires, with a spiral winding angle of 80 to 90 degrees, and the axial distance of each second steel wire is 1 / 3 or 1 / 4 of the pitch length.
8. The spiral-wound composite ultra-low temperature flexible pipe including a plurality of inner and outer carcass steel wires of claim 1, characterized in that, The first and second steel wires are made of 316L stainless steel or carbon fiber.
9. A method of designing the structure of a spiral-wound composite ultra-low temperature flexible pipe incorporating a plurality of inner and outer carcass steel wires as claimed in any of claims 1 to 8, characterised in that, Includes the following steps: Step 1: Determine a reasonable pipe structure and select an appropriate pipe inner diameter based on the actual engineering application background; Step 2: Calculate the structural dimension range of the inner and outer skeleton steel wires and the middle four-layer membrane structure based on the geometric relationship of the pipe cross section, so that the inner and outer skeleton steel wires and the middle membrane structure fit together tightly and the pipe as a whole presents a corrugated shape. The structural dimensions include: the geometric relationship between the cross-sectional diameter of the inner and outer skeleton steel wires and the overall corrugated shape of the pipe; the structural parameters of the helix angle and pitch of the inner and outer skeleton steel wires; and the geometric parameters of the crests and troughs of the overall corrugated shape of the pipe. Step 3: Based on the thermodynamic heat transfer principle and the heat balance equation, and assuming that the internal temperature of the pipe is maintained at -163℃ and the external temperature of the pipe is maintained at 0℃, complete the design of the pipe insulation layer. Step 4, according to the actual sea conditions of engineering application background, the overall performance of the pipeline is analyzed, the overall layout scheme of the pipeline and the tension, bending and torsion working condition parameters are determined, and according to the comprehensive requirements of stiffness, strength and stability, the structure design of each layer of the pipeline is finally determined.