Local non-adhesive nonmetal intelligent flexible pipe and preparation method thereof

Abstract

The invention relates to a locally non-adhesive nonmetal intelligent flexible pipe and a preparation method thereof.The flexible pipe comprises a lining layer, a blocking layer, an inner pressure resisting layer, an outer pressure resisting layer, a tensile layer and a protective layer which are sequentially arranged from inside to outside, and the adjacent layers of the inner pressure resisting layer, the outer pressure resisting layer, the tensile layer and the protective layer are in a non-adhesive state; the lining layer and the blocking layer are connected in a bonding mode. According to the local non-bonding non-metal intelligent flexible pipe provided by the invention, through the unique interlayer non-bonding structure and the fiber reinforced thermoplastic composite material system design and in combination with the built-in distributed optical fiber sensing network, multiple innovative technical breakthrough is realized. The flexible pipe not only has good medium corrosion resistance, gas permeability resistance and bendability, but also has good temperature resistance and pressure resistance, and can be used for dynamic marine risers and static submarine pipelines.

Description

Technical Field

[0001] The present invention relates to a locally non-bonded non-metallic intelligent flexible pipe and a preparation method thereof, belonging to the technical field of agricultural machinery and equipment. Background Art

[0002] With the continuous deepening of marine resource development, especially the rapid development in fields such as deep-sea oil and gas fields, seabed mineral extraction, and marine renewable energy (such as offshore wind power), the performance requirements for marine engineering equipment are increasing day by day. Among them, as the core component connecting the underwater production system and the surface platform, the conveying pipeline needs to have excellent corrosion resistance, fatigue resistance, lightweight characteristics, and environmental adaptability to meet the long-term stable operation requirements under complex marine conditions. Traditional marine pipelines are mostly made of metal materials (such as carbon steel, stainless steel, or duplex steel). However, metal pipelines have significant defects in the marine environment: First, they are prone to electrochemical corrosion or stress corrosion cracking when exposed to high-salinity seawater, dissolved oxygen, and microbial environments for a long time, resulting in high maintenance costs and limited service life; Second, the self-weight of metal pipelines is relatively large, and additional buoyancy devices need to be configured in deep-water applications, increasing the installation complexity and cost; Third, the rigid structure is difficult to adapt to seabed topography changes or dynamic loads (such as ocean current impacts, platform movements), which is prone to cause local stress concentration and increase the leakage risk. To overcome the limitations of metal pipelines, non-metallic flexible pipes have gradually become a research hotspot. Such pipelines usually adopt polymer-based composite materials (such as high-density polyethylene, polyamide) or reinforced thermoplastics, combined with fiber-reinforcing layers (such as aramid, carbon fiber) to form a multi-layer composite structure, with the advantages of corrosion resistance, lightweight, and flexibility. However, there are still some problems with existing non-metallic flexible pipes, and it is necessary to develop a new non-metallic flexible pipe. Summary of the Invention

[0003] Aiming at the above technical problems, the present invention provides a locally non-bonded non-metallic intelligent flexible pipe and a preparation method thereof. This flexible pipe not only has good corrosion resistance to media, gas permeability, and bendability, but also has good temperature resistance and pressure resistance, and can be used for dynamic marine risers and static subsea pipelines.

[0004] To achieve the above object, the present invention adopts the following technical solutions:

[0005] A locally non-bonded non-metallic intelligent flexible pipe includes: a lining layer, a barrier layer, an internal pressure-resistant layer, an external pressure-resistant layer, a tensile layer, and a protective layer arranged in sequence from inside to outside, and the adjacent layers among the internal pressure-resistant layer, the external pressure-resistant layer, the tensile layer, and the protective layer are in a non-bonded state, and the lining layer and the barrier layer are adhesively connected.

[0006] For the described locally non-bonded non-metallic intelligent flexible pipe, preferably, the inner liner is a non-metallic inner liner, which is formed by plastic extrusion and then processed to have spiral grooves for laying optical fibers. After placing the optical fibers, the optical fibers are embedded by secondary extrusion with plastic to form the non-metallic inner liner.

[0007] For the described locally non-bonded non-metallic intelligent flexible pipe, preferably, the barrier layer is formed by stacking and winding metal strips on the outer surface of the inner liner, and adhesives are provided at the interfaces between the metal strips and the outer surface of the inner liner as well as between adjacent metal strips.

[0008] For the described locally non-bonded non-metallic intelligent flexible pipe, preferably, the metal strip is an aluminum strip, the width of the aluminum strip is 10 - 40 mm, the thickness of the aluminum strip is 0.05 - 0.5 mm, and the thickness of the barrier layer is 0.5 - 5 mm.

[0009] For the described locally non-bonded non-metallic intelligent flexible pipe, preferably, the internal pressure resistance layer is a multi-layer structure formed by winding fiber bundles at a set angle on the outer surface of the barrier layer. The number of winding layers of the fiber bundles is an even number, and the winding angles of adjacent fiber bundle layers are the same but in opposite directions.

[0010] For the described locally non-bonded non-metallic intelligent flexible pipe, preferably, the core of the fiber bundle is an untwisted fiber bundle, and the fiber bundle has an outer protective layer, which is a woven or extruded abrasion-resistant protective layer, and / or

[0011] The diameter of the fiber bundle is 2 - 10 mm and the number of winding layers is 2 - 8 layers.

[0012] For the described locally non-bonded non-metallic intelligent flexible pipe, preferably, the external pressure resistance layer is formed by splicing several external pressure resistance members, and the splicing forms include one or more of mortise and tenon, bonding or welding.

[0013] For the described locally non-bonded non-metallic intelligent flexible pipe, preferably, the tensile layer is a multi-layer structure formed by winding fiber bundles at a set angle on the outer surface of the external pressure resistance layer. The number of winding layers of the fiber bundles is an even number, and the winding angles of adjacent fiber bundle layers are the same but in opposite directions.

[0014] For the described locally non-bonded non-metallic intelligent flexible pipe, preferably, the thickness of the external pressure resistance layer is 5 - 20 mm, and / or

[0015] The diameter of the fiber bundle is 2 - 10 mm and the number of winding layers is 2 - 8 layers.

[0016] The second aspect of the present invention provides a preparation method for a locally non-bonded non-metallic intelligent flexible pipe, including the following steps:

[0017] The thermoplastic is melt-extruded, shaped, and cooled to obtain a plastic pipe with a preset inner diameter. A spiral groove is machined on the outer surface of the plastic pipe, and an optical fiber is placed in the spiral groove. Then, the plastic pipe is extruded and coated for a second time, covering it with a plastic layer that has strong adhesiveness to the barrier layer, completing the processing of the inner lining layer;

[0018] An adhesive tape with an adhesive and a metal tape are wound around the outer surface of the inner lining layer. The metal tape is wound in an overlapping form to form a barrier layer. Adhesives are provided at the overlapping surfaces of the metal tape to ensure tight bonding between the metal tapes and between the metal tape and the inner lining layer;

[0019] A fiber bundle is wound around the outer surface of the barrier layer at a set angle in multiple layers using a winding machine to form an internal pressure-resistant layer;

[0020] An external pressure-resistant component is processed using an injection machine, assembled and spliced on the outer surface of the internal pressure-resistant layer, and the connection points are riveted, welded, or bonded to form a complete external pressure-resistant layer with the external pressure-resistant component;

[0021] The winding machine is used again to wind a fiber bundle around the outer surface of the external pressure-resistant layer at a set angle in multiple layers to form a tensile layer;

[0022] The thermoplastic is extruded onto the outer surface of the tensile layer, shaped, and cooled to complete the covering of the protective layer.

[0023] Due to the adoption of the above technical solutions, the present invention has the following advantages:

[0024] 1. The present invention adopts a non-bonding dynamic coupling structure design. Compared with the traditional bonding structure, the anti-buckling performance is improved, and the bending radius can be greatly reduced, significantly enhancing the adaptability to complex working conditions.

[0025] 2. The integrated multi-parameter self-sensing system can monitor parameters such as strain, temperature, and micro-leakage in real time, and can accurately locate them, realizing the health management of the entire life cycle of the pipeline, reducing the maintenance cost and the sudden failure rate.

[0026] 3. The introduction of the metal barrier layer greatly restricts the diffusion and penetration of gas, significantly improving the gas barrier performance of the pipeline.

[0027] 4. The pressure-resistant layer that is divided into parts is a flexible pipe, which is more convenient to manufacture. Through the collaborative innovation of the structure-material-sensing system, the present invention provides a safe, reliable, intelligent, and efficient transportation solution for fields such as deep-sea oil and gas development, urban utility tunnels, and hydrogen energy transportation. Brief Description of the Drawings

[0028] Figure 1 Schematic diagram of a marine flexible riser provided as one of the prior arts;

[0029] Figure 2Schematic diagram of a flexible pipe for oil, gas and hydrogen transportation provided by the second prior art;

[0030] Figure 3 Schematic diagram of a non-metallic non-bonded fiber-reinforced composite flexible pipe provided by the third prior art;

[0031] Figure 4 Schematic diagram of the external pressure resistance layer provided by the present invention;

[0032] Figure 5 Schematic diagram of an external pressure resistance member spliced with the external pressure resistance layer. Detailed implementation manners

[0033] To make the objectives, technical solutions and advantages of the present invention clearer, the technical solutions in the present invention will be clearly and completely described below. Apparently, the described embodiments are some but not all of the embodiments of the present invention. All other embodiments obtained by those of ordinary skill in the art based on the embodiments in the present invention without creative efforts shall fall within the scope of protection of the present invention.

[0034] Unless otherwise defined, the technical terms or scientific terms used in the present invention shall have the ordinary meanings understood by those of ordinary skill in the art to which the present invention pertains. The terms "first", "second", "third", "fourth" and similar terms used in the present invention do not denote any order, quantity or importance, but are only used to distinguish different components. The terms such as "including" or "comprising" mean that the elements or items appearing before this word cover the elements or items listed after this word and their equivalents, without excluding other elements or items. The terms such as "connected" or "coupled" are not limited to physical or mechanical connections, but may include electrical connections, whether direct or indirect.

[0035] For the convenience of description, spatial relative relationship terms may be used in the text to describe the relationship between one element or feature shown in the figure and another element or feature, such relative relationship terms such as "inner", "outer", "inner side", "outer side", "below", "above", etc. Such spatial relative relationship terms are intended to include different orientations of the device in use or operation in addition to the orientations depicted in the figure.

[0036] One of the prior arts discloses an offshore flexible riser, as Figure 1As shown in the figure, the pipe wall of the marine flexible pipe successively includes, from inside to outside: a skeleton layer, a lining layer, a compressive armor layer, a tensile armor layer, and an outer protective layer. The compressive armor layer or the tensile armor layer is a resin fiber composite layer, which is a composite material of cured resin and fiber. The skeleton layer is composed of an interlocking metal material, and the lining layer is composed of a thermoplastic plastic. However, there are the following defects. Defect 1: The skeleton layer is in the innermost part and is in direct contact with the medium inside the pipe. The skeleton layer is made of metal material. When the transported fluid is corrosive, the metal skeleton is prone to corrosion failure. Defect 2: The armor layer is spirally wound by linear or strip-shaped resin fiber composite materials. This type of material is a continuous resin fiber composite material, and the production process is complex. After quality problems occur during the production process, the entire pipe will be discarded and cannot be repaired again.

[0037] The second prior art discloses a flexible pipe for oil, gas, and hydrogen transportation, as Figure 2 shown. The pipe successively includes, from inside to outside, a lining layer, a reinforcing layer, an inner protective layer, a counterweight layer, and an outer protective layer. The lining layer is composed of a polymer, and the reinforcing layer is composed of metal filaments. There are the following defects. Defect 1: The gas barrier ability of the polymer lining layer is weak. The lining layer of this invention is a polymer material. Compared with metal materials, polymers have a large amount of free volume inside, and gases such as hydrogen and hydrogen sulfide are easy to penetrate the lining layer. Defect 2: The reinforcing layer made of metal material is prone to failure. The reinforcing layer of this pipe is metal wire, and this metal material is prone to failure in a corrosive medium. For example, in an environment of hydrogen and hydrogen sulfide, stress cracking is likely to occur, the reinforcing layer is damaged, and the entire pipe fails.

[0038] The third prior art discloses a non-metal non-bonded fiber layer, as Figure 3 shown. It successively includes, from inside to outside: a lining layer, a first internal pressure resistance reinforcing layer, a first anti-wear layer, a second internal pressure resistance reinforcing layer, a second anti-wear layer, an external pressure resistance reinforcing layer, an anti-seepage layer, a first tensile strength reinforcing layer, a third anti-wear layer, a second tensile strength reinforcing layer, and a protective layer. And a Kevlar hybrid optical fiber cable is provided in the first internal pressure resistance reinforcing layer. All structural layers are non-metal materials, and there is non-bonded contact between each adjacent layer. This composite pipe is lightweight, has good properties, is corrosion-resistant, has good anti-seepage performance, is convenient for processing and manufacturing, and has good internal pressure resistance and external pressure resistance. At the same time, it can realize real-time monitoring of the working state of the flexible pipe, can adapt to harsh marine environments

[0039] Based on the above technical problems, the present invention provides a locally non-bonded non-metallic intelligent flexible pipe and a preparation method thereof. The non-metallic flexible pipe is successively provided with a lining layer, a barrier layer, an internal pressure-resistant layer, an external pressure-resistant layer, a tensile layer and a protective layer from inside to outside. And between adjacent two of the outermost four layers is a non-bonded connection. Among them, the material of the lining layer is a thermoplastic polymer, and optical fibers are laid inside it. The barrier layer is formed by winding metal strips, and there are adhesives between it and the lining layer and at the metal lap joints. The internal pressure-resistant layer is formed by winding fiber bundles with an outer protective layer. The external pressure-resistant layer is formed by splicing injection-molded reinforced plastic parts. The tensile layer is also formed by winding fiber bundles with an outer protective layer. The outermost protective layer is extruded from a thermoplastic polymer material.

[0040] As Figure 4 , 5 shown, the locally non-bonded non-metallic intelligent flexible pipe involved in the present invention includes: a lining layer, a barrier layer, an internal pressure-resistant layer, an external pressure-resistant layer, a tensile layer and a protective layer arranged successively from inside to outside, and between adjacent layers of the outermost four layers is a non-bonded state. Among them, the material of the lining layer is a thermoplastic polymer, and an optical fiber sensor is laid inside it. The barrier layer is formed by winding metal strips, and there are adhesives between it and the lining layer and at the adjacent metal strip lap joints. The internal pressure-resistant layer is formed by winding fiber bundles with an outer protective layer. The external pressure-resistant layer is formed by splicing injection-molded reinforced plastic components. The tensile layer is also formed by winding fiber bundles with an outer protective layer. The protective layer is extruded from a thermoplastic polymer material.

[0041] Specifically, the lining layer is a thermoplastic polymer plastic (such as: polyethylene, polyvinylidene fluoride, nylon 11, etc.), which is extruded and formed by an extruder. After extrusion, spiral grooves are machined on the outer surface. After laying optical fibers in the spiral grooves, secondary extrusion is carried out to embed the optical fibers with the thermoplastic plastic, forming the lining layer of the flexible pipe. The total thickness of the lining layer is 5 - 20 mm.

[0042] Further, the barrier layer is formed by winding metal strips on the outer surface of the lining layer. The metal strips overlap and lap, and there are adhesives on the surface of the metal strips and the lining layer and at the adjacent metal strip lap surfaces to ensure the formation of a sealed and integral sealing layer. The metal strip is preferably an aluminum strip, the width of the aluminum strip is 10 - 40 mm, the thickness of the aluminum strip is 0.05 - 0.5 mm, and the total thickness of the entire barrier layer is 0.5 - 5 mm.

[0043] Further, in a specific example of the present invention, the internal pressure-resistant layer is a multi-layer structure formed by winding fiber bundles with an outer protective layer at a certain angle. The number of winding layers of the fiber bundles is an even number, and the rotation angles of the fiber bundles in adjacent layers are the same and the rotation directions are opposite. The inner core of the fiber bundle with an outer protective layer is an untwisted fiber bundle, and the outer layer is a woven or extruded anti-wear protective layer. The diameter of the fiber bundle is 2 - 10 mm, and the number of winding layers of the fiber bundle is 2 - 8 layers.

[0044] Further, the external pressure resistance layer is formed by splicing multiple injection-molded thermoplastic polymer composite components (the composite materials include thermoplastic plastics reinforced with glass fiber, carbon fiber or carbon nanotubes, and the thermoplastic plastics include polyethylene, polypropylene, ABS, nylon, polycarbonate, etc.). The splicing forms include one or more of mortise and tenon, bonding or welding. In this way, the components can be assembled together to form an integral spiral strip, and a locking structure can be formed between the strips to control the bending angle of the spiral strip. The thickness of the external pressure resistance layer is 5-20 mm, and 3-6 components form a complete spiral cycle.

[0045] In the present invention, the tensile layer is produced in the same way as the internal pressure resistance layer, except that the winding angle of this layer is different from that of the internal pressure resistance layer. The diameter of the fiber bundle is 2-10 mm, and the winding layer number of the fiber bundle is 2-8 layers.

[0046] The present invention also provides a preparation method for a locally non-bonded non-metallic intelligent flexible pipe, including the following steps:

[0047] Step 1: Melt and extrude the thermoplastic polymer, and after shaping and cooling, obtain a plastic pipe with a preset inner diameter. By means of machining on the outer surface of the plastic pipe, a spiral groove is constructed on the outer surface of the plastic pipe, and an optical fiber sensor is placed in the groove. Then, the plastic pipe is extruded and coated for the second time, and a polymer material with strong adhesiveness to the barrier layer is coated to complete the processing of the inner lining layer.

[0048] Step 2: Wind the metal strip and the adhesive strip on the outer surface of the inner lining layer. The metal strip is wound in an overlapping form, and adhesives are provided at the metal strip in contact with the inner lining layer and the overlapping part of the metal strips to ensure tight bonding between the metal strips and between the metal strip and the inner lining layer.

[0049] Step 3: Use a winding machine to wind high-strength fiber bundles on the outer surface of the above-mentioned inner lining pipe at a certain angle, and perform multiple-layer winding according to the design requirements to form an internal pressure resistance layer.

[0050] Step 4: Process the external pressure resistance components using an injection machine according to the design requirements, assemble and splice the external pressure resistance components on the outer surface of the internal pressure resistance layer, and perform riveting, welding or bonding at the joints to make the external pressure resistance components form a complete spiral body.

[0051] Step 5: Use the winding machine again to perform multiple-layer winding of high-strength fiber bundles outside the external pressure resistance layer to construct the tensile layer of the flexible pipe.

[0052] Step 6: Extrude the thermoplastic polymer onto the outer surface of the tensile layer, and after shaping and cooling, complete the coating of the protective layer.

[0053] The locally non-bonded non-metallic intelligent flexible pipe provided by the present invention has achieved multiple innovative technological breakthroughs through a unique interlayer non-bonded structure and the design of a fiber-reinforced thermoplastic composite material system. Specifically, there is an adhesive layer between the inner liner pipe and the barrier layer metal strip, which can bond the barrier layer to form a whole, preventing gas from diffusing between the metal strips and improving the gas barrier performance of the entire pipe; second, the manufacturing method of the external pressure-resistant layer proposed in the present invention is brand new. Currently, the flexible external pressure-resistant layers are all formed by winding continuous strips. If there is a quality problem with one of the strips, the entire pipe will be scrapped. The present invention proposes to process high-strength thermoplastic fiber composite materials into thermoplastic polymer composite components as shown in Figure 5 . These components can form a whole cylindrical shape through splicing or bonding and serve as a pressure-bearing layer to resist external pressure.

[0054] The locally non-metallic non-bonded intelligent flexible pipe provided by the present invention not only has good corrosion resistance to media, gas permeability resistance, and bendability, but also has good temperature resistance and pressure resistance, and can be used for dynamic marine risers and static subsea pipelines.

[0055] Finally, it should be noted that the above embodiments are only used to illustrate the technical solutions of the present invention and are not intended to limit them; although the present invention has been described in detail with reference to the foregoing embodiments, those of ordinary skill in the art should understand that they can still modify the technical solutions recorded in the foregoing embodiments, or perform equivalent replacements for some of the technical features; and these modifications or replacements do not cause the essence of the corresponding technical solutions to deviate from the spirit and scope of the technical solutions of the various embodiments of the present invention.

Claims

1. A locally non-bonded non-metallic intelligent flexible tube, characterized in that, Including: An inner lining layer, a barrier layer, an internal pressure resistance layer, an external pressure resistance layer, a tensile layer and a protective layer which are arranged in sequence from inside to outside, and the adjacent layers among the internal pressure resistance layer, the external pressure resistance layer, the tensile layer and the protective layer are in a non-bonded state, while the inner lining layer and the barrier layer are adhesively connected.

2. The locally non-bonded non-metallic intelligent flexible pipe according to claim 1, wherein, The inner lining layer is a non-metallic inner lining layer, which is formed by plastic extrusion and then processed to form spiral grooves for laying optical fibers. After the optical fibers are placed, plastic is used for secondary extrusion to embed the optical fibers, thereby forming the non-metallic inner lining layer.

3. The locally non-bonded non-metallic intelligent flexible pipe according to claim 1, characterized in that, The barrier layer is formed by stacking and winding metal strips on the outer surface of the inner lining layer, and adhesives are provided at the outer surface of the metal strips and the overlapping surfaces of adjacent metal strips.

4. The locally non-bonded non-metallic intelligent flexible pipe according to claim 3, wherein, The metal strip is an aluminum strip, the width of the aluminum strip is 10 - 40 mm, the thickness of the aluminum strip is 0.05 - 0.5 mm, and the thickness of the barrier layer is 0.5 - 5 mm.

5. The locally non-bonded non-metallic intelligent flexible pipe according to claim 1, wherein The internal pressure resistance layer is a multi-layer structure formed by winding fiber bundles around the outer surface of the barrier layer at a set angle. The winding layers of the fiber bundles are even numbers, and the winding angles of adjacent fiber bundle layers are the same but in opposite directions.

6. The partial non-bonded non-metallic intelligent flexible pipe according to claim 5, wherein The core of the fiber bundle is an untwisted fiber bundle, and the fiber bundle has an outer protective layer, and the outer protective layer is a woven or extruded abrasion-resistant protective layer, and / or The diameter of the fiber bundle is 2 - 10 mm and the winding layers are 2 - 8 layers.

7. The locally non-bonded non-metallic intelligent flexible pipe according to claim 1, wherein The external pressure resistance layer is formed by splicing a number of external pressure resistance components, and the splicing forms include one or more of mortise and tenon, adhesion or welding.

8. The partial non-bonded non-metallic intelligent flexible pipe according to claim 7, characterized in that, The tensile layer is a multi-layer structure formed by winding fiber bundles around the outer surface of the external pressure resistance layer at a set angle. The winding layers of the fiber bundles are even numbers, and the winding angles of adjacent fiber bundle layers are the same but in opposite directions.

9. The partial non-bonded non-metallic intelligent flexible pipe according to claim 8, characterized in that, The thickness of the external pressure resistance layer is 5 - 20 mm, and / or The diameter of the fiber bundle is 2 - 10 mm and the winding layers are 2 - 8 layers.

10. A method for preparing a locally non-bonded non-metallic intelligent flexible tube, characterized in that, Including the following steps: Melting, extruding, shaping and cooling thermoplastic plastics to obtain a plastic pipe with a preset inner diameter, processing spiral grooves on the outer surface of the plastic pipe, laying optical fibers in the spiral grooves, and then performing secondary extrusion coating on the plastic pipe to coat a plastic layer with strong adhesiveness to the barrier layer to complete the processing of the inner lining layer; Winding an adhesive tape with an adhesive and metal strips on the outer surface of the inner lining layer, and winding the metal strips in an overlapping form to form a barrier layer. Adhesives are provided at the overlapping surfaces of the metal strips to ensure tight adhesion between the metal strips and between the metal strips and the inner lining layer; Using a winding machine to wind fiber bundles around the outer surface of the barrier layer at a set angle in multiple layers to form an internal pressure resistance layer; Using an injection machine to process external pressure resistance components, assembling and splicing the external pressure resistance components on the outer surface of the internal pressure resistance layer, and riveting, welding or bonding the joints to make the external pressure resistance components form a complete external pressure resistance layer; Using the winding machine again to wind fiber bundles around the outer surface of the external pressure resistance layer at a set angle in multiple layers to form a tensile layer; Extruding thermoplastic plastics onto the outer surface of the tensile layer, shaping and cooling to complete the coating of the protective layer.

Images