CN114382957B

CN114382957B - LNG low-temperature hose body forming method

Info

Publication number: CN114382957B
Application number: CN202210040477.7A
Authority: CN
Inventors: 李欣欣; 刘淼儿; 程昊; 杨亮; 范明龙; 罗婷婷; 李方遒; 李恩道; 鲁亮; 盖小刚
Original assignee: CNOOC Gas and Power Group Co Ltd
Current assignee: CNOOC Gas and Power Group Co Ltd
Priority date: 2022-01-14
Filing date: 2022-01-14
Publication date: 2023-12-01
Anticipated expiration: 2042-01-14
Also published as: CN114382957A

Abstract

The application relates to a method for forming an LNG low-temperature hose body, which comprises the following steps: the sealing layer at the innermost layer of the pipe body is formed into a corrugated pipe after the seamless steel pipe is spun and thinned; the filling layer of the secondary lining layer of the pipe body is formed by wrapping low-temperature-resistant filling cotton on the corrugated pipe, and then fixing the heat-insulating filling cotton on the corrugated pipe by adopting a glass fiber band through a winding process; the armor layer of the pipe body outside the filling layer fixes the braid on the filling layer in a winding mode; the cold insulation layer of the pipe body outside the armor layer fixes the adhesive tape on the armor layer in a winding mode; the leakage monitoring layer of the pipe body positioned outside the cold insulation layer is formed by laying a low-temperature-resistant armored sensing optical cable; the outer protective layer of the outermost layer of the pipe body is formed by extruding and coating the secondary outer layer of the pipe body. The forming process of the application considers the compatibility and operation elasticity of the hose size, the hose of the application has low temperature resistance at minus 196 ℃, pressure resistance not lower than 1.2MPa, bending radius not higher than 10 times of the inner diameter of the hose, stable pressure bearing capacity and higher flexibility.

Description

LNG low-temperature hose body forming method

Technical Field

The application relates to the technical field of oil and gas resource storage and transportation, in particular to a method for forming an LNG low-temperature hose body.

Background

LNG (liquefied natural gas) receiving terminals can be classified into land receiving terminals and offshore receiving terminals. Land-based receiving terminals are now in wide use worldwide and are still evolving rapidly as the demand for natural gas increases. Offshore LNG receiving terminals are a new receiving terminal proposed in recent years. Offshore LNG receiving terminals can be further divided into floating receiving terminals and stationary receiving terminals, wherein the stationary receiving terminals are similar to the land receiving terminals. According to the different forms of LNG receiving terminals, the LNG unloading modes adopted are different.

The floating liquefied natural gas production storage and offloading device (LNG Floating Production Storage and offloading Unit, FLNG) is a floating production device for offshore natural gas field development, is positioned on the sea through a mooring system, has the functions of exploiting, processing, liquefying, storing and loading and unloading natural gas, and realizes the exploitation and natural gas transportation of the offshore natural gas field by being matched with a liquefied natural gas (Liquefied Natural Gas, LNG) ship. The offshore gas field development by utilizing FLNG ends the single mode that the offshore gas field can only be transported by pipelines to land, so that the transportation cost is saved, and the land space is not occupied. In addition, FLNG can also be used for a second time after gas field exploitation is finished, and the FLNG is arranged in other natural gas fields and has higher economic performance.

Aiming at the severe sea conditions of the south China sea, if the existing mooring technology is difficult to effectively solve the problem of differential motion between the FLNG floating platform and the carrier of the transport ship, a specially designed low-temperature unloading system is required to meet the severe requirements of low-temperature and shaking working conditions. The low-temperature hose conveying system has obvious comprehensive advantages in the aspects of weight, flexibility, corrosion resistance, heat insulation and the like, and an effective mode is that the low-temperature hose conveying system adopts tandem mooring, namely, the low-temperature hose conveying system is connected with an LNG carrier through a mooring rope, and is used for discharging the LNG stored by the FLNG, and the LNG stored by the FLNG is conveyed to the carrier, so that the low-temperature hose is required to bear the ultralow-temperature working condition, and meanwhile, the influence of relative motion between the FLNG and the LNG carrier is required to be overcome.

In conclusion, the key technology of the LNG low-temperature hose conveying system relates to various links such as low-temperature manufacturing, test verification and the like. The low-temperature hose is an important ring, the manufacture of the hose involves a plurality of links such as low-temperature material selection, processing technology, molding manufacture, sealing and the like, the technical difficulty is high, the requirement on equipment capacity is high, and equipment such as molding, winding, braiding and the like of each layer of material of the hose needs to be processed in a professional way. In the prior art, a processing technology specially aiming at the multi-layer composite low-temperature hose does not exist.

Disclosure of Invention

Aiming at the defects of the prior art, the application aims to provide an LNG low-temperature hose body and a forming process, and the process can be used for processing and manufacturing a multi-layer composite low-temperature hose so as to obtain a high-performance low-temperature hose.

The application provides a method for forming an LNG low-temperature hose body, which comprises the following steps:

the sealing layer at the innermost layer of the pipe body is formed into a corrugated pipe after the seamless steel pipe is spun and thinned;

filling the prefabricated low-temperature-resistant corrugated polyolefin foam tape on the corrugated pipe by the filling layer of the secondary lining layer of the pipe body, and winding and fixing the polyolefin foam tape on the corrugated pipe by adopting a glass fiber tape through a winding process;

the armor layer of the pipe body outside the filling layer fixes the braid on the filling layer in a winding mode;

the cold insulation layer of the pipe body outside the armor layer fixes the adhesive tape on the armor layer in a winding mode;

the leakage monitoring layer of the pipe body positioned between the cold insulation layers is formed by laying a low-temperature-resistant armored sensing optical cable;

the outer protective layer of the outermost layer of the pipe body is formed by extruding and coating the secondary outer layer of the pipe body.

According to one embodiment of the application, spin-thinning the seamless steel tube comprises:

firstly, carrying out spinning cogging treatment for 1 time, then carrying out vacuum annealing heat treatment, and then carrying out spinning thinning forming for 4 times.

According to one embodiment of the present application, the forming of the seamless steel pipe into the corrugated pipe after spin-thinning includes: after the spinning process, a vacuum solution heat treatment is performed.

According to one embodiment of the application, when the corrugated pipe is formed, the wave height is 15-19mm, the wave distance is 12-13mm, and the wall thickness is 0.6-1.0mm (the structure can be adjusted according to the practical application working condition).

According to one embodiment of the present application, the forming the seamless steel pipe into the corrugated pipe after spin-thinning further includes:

and welding a plurality of single-section corrugated pipes into a required length through argon arc welding and evaluating the air tightness of welding seams, wherein preferably, the end faces of adjacent welded corrugated pipes are firstly disconnected at inner wave crests, then the vertical surfaces of the wave crests are ground flat, two end planes are aligned during welding, and then the R angle of the outer wave crest is welded, wherein the R angle is the arc angle corresponding to the wave crest or the wave trough.

After the single-section corrugated pipe is welded, when the outer layers are processed, the end joint inner core processed by a lathe is welded on the corrugated pipe in advance. The welding process is the same as the corrugated pipe peak welding process. And (5) performing hydrostatic test after the joint is welded.

According to one embodiment of the application, when the armor layer is wound, two layers of aramid fiber woven belts are adopted by a winding machine to perform two-layer reverse winding, the winding tension is 80-100N, the axial winding angle is 20-25 degrees, and the thickness of each layer of aramid fiber woven belt is 1-2mm.

According to one embodiment of the present application, the cold insulation layer includes, when wound: the air-setting adhesive tape is adopted to wind a plurality of layers, the tension is not lower than 50N during winding, and the thickness of each layer of the air-setting adhesive tape is 5-10mm (different layers and thicknesses are selected according to the heat insulation requirements of the hose, and the thicknesses of different layers can be the same or different).

According to one embodiment of the application, the leak-monitoring layer shaping comprises:

the low-temperature-resistant armored sensing optical cable is wound and laid, 1-2 core sensing optical fibers are arranged in the low-temperature-resistant armored sensing optical cable, the outside of the optical fibers is sequentially protected by a stainless steel spiral pipe, high-modulus Kevlar aramid yarns (reinforcing pieces), a woven mesh and a special plastic outer sheath, the optical cable laying mode is preferably spirally arranged and laid between two cold insulation layers (namely, the optical cable is laid outside a certain cold insulation layer in a spiral winding mode).

According to one embodiment of the present application, the forming of the outer protective layer includes: any one of CPE (chlorinated polyethylene), HDPE (high density polyethylene), PA11 (nylon-11), TPU (polyether material), PVC (polyvinyl chloride) and PE (polyethylene) can be adopted for extrusion molding.

The thickness of the outer protective layer is 5-10mm, and the deviation between the upper and lower parts is +/-0.5 mm.

According to one embodiment of the present application, the method further comprises an end fitting forming and installing process comprising: welding a concave ring outside a prefabricated inner core of a pipe body, sleeving a convex ring on a tension belt through buckling and pressing, and buckling and pressing the convex ring at the position of the concave ring through a buckling and pressing die, so that the concave ring and the convex ring are reversely locked, and the buckling and pressing pressure is preferably not more than 5Mpa; the prefabricated inner support sleeve is buckled on the cold insulation layer through a buckling and pressing machine in a buckling and pressing mode, the inner support sleeve is welded and fixed with the prefabricated inner core, and an optical cable penetrating port is reserved at one end of the inner support sleeve; the prefabricated joint outer skin is buckled and pressed on the outer sheath layer through a buckling and pressing machine; then welding a flange on the prefabricated inner core; and then, carrying out hydrostatic test, wherein the test pressure is not more than 1.5 times of the design pressure.

The application can obtain the low-temperature hose with light weight, good flexibility, strong corrosion resistance and excellent cold and heat insulation performance by adopting the forming method.

Drawings

FIG. 1 is a schematic cross-sectional view of a cryogenic hose according to an embodiment of the application;

FIG. 2 is a schematic diagram of a welded cross-section of a bellows in accordance with one embodiment of the present application;

FIG. 3 is a schematic diagram of a corrugated tubing wave soldering point in accordance with one embodiment of the present application;

FIG. 4 is a schematic illustration of an end preform core weld in accordance with an embodiment of the present application;

FIG. 5 is a schematic illustration of a polyolefin foam tape secured to a bellows in accordance with an embodiment of the present application;

FIG. 6 is a schematic diagram of a low temperature resistant armored sensor cable according to an embodiment of the present application;

fig. 7 is a schematic view of an armor layer winding machine according to an embodiment of the present application;

FIG. 8 is a schematic view of a cold insulation layer winding machine according to an embodiment of the application;

FIG. 9 is a schematic view of an extruder for forming an outer sheath according to one embodiment of the present application;

FIG. 10 is a schematic view of an end fitting forming structure according to an embodiment of the present application;

reference numerals:

1-first section, 2-second section, 3-R angle, 4-prefabricated core welding point, 5-prefabricated core, 6-polyolefin foam tape and 7-optical fiber; 8-reinforcing parts, 9-stainless steel spiral pipes, 10-woven mesh, 11-outer jackets, 12-rollers, 13-cage angle winding machines, 14-cold insulation layer winding rollers, 15-double-layer winding machines, 16-glass fiber ribbon winding machines, 17-extruders, 18-water tanks, 19-tractors, 20-concave rings, 21-convex rings, 22-inner supporting sleeves, 23-joint outer covers and 24-flanges.

Detailed Description

The preferred embodiments of the present application will be described in detail below with reference to the attached drawings, so that the objects, features and advantages of the present application will be more clearly understood. It should be understood that the embodiments shown in the drawings are not intended to limit the scope of the application, but rather are merely illustrative of the true spirit of the application.

Aiming at the critical problem that the existing LNG low-temperature hose processing technology lacks in the industry and is urgently needed to be solved, the application provides an LNG low-temperature hose body and a forming process, so as to fill the blank of the prior art and solve the critical problem in the industry.

Before describing the LNG cryogenic hose body and the forming process, for ease of understanding, the LNG cryogenic hose structure will be described first. As shown in fig. 1, a schematic cross-sectional structure of the cryogenic hose is shown, from which the cryogenic hose structure mainly includes, from inside to outside: sealing layer (be used for sealing low temperature medium and bear the weight of the internal pressure of hose for LNG realizes flowing transport in the sealing layer is inside), armor (reinforcing hose axial tensile strength, guarantee the atress intensity of hose), cold insulation layer (provide low temperature medium cold insulation, reduce cold damage, prevent phenomenon such as frost ice appear in the low temperature hose outside), leak monitoring layer (carry out state monitoring to low temperature hose operation process, can in time discover and take effective safeguard measure when low temperature medium leaks appear), outer inoxidizing coating (protection low temperature hose, and can dampproofing keep apart, prevent outside steam infiltration hose is inside), can set up middle auxiliary layer depending on concrete processing method between each layer. All the functional layer materials of the low-temperature hose are ultra-low temperature resistant flexible materials, so that the high operation elasticity of the low-temperature hose can be ensured, the low-temperature hose can be curled and retracted in the operation process, and the storage and the transportation are convenient.

Based on the structural and functional characteristics of the LNG low-temperature hose, the application provides a molding process of the LNG low-temperature hose body, so that the structure can be standardized and produced:

(1) The LNG cryogenic hose body and the forming process take into account the compatibility of hose dimensions and operational flexibility. Taking a low-temperature hose with the inner diameter of 8 inches as an example, the hose body with the inner diameter of 200mm-250mm and the wall thickness of 55mm-85mm can be realized, and the hose sample piece with the length of 2m-100m can be used;

(2) The processing technology is suitable for the hose structure and material model selection, the technological parameters are adjustable and controllable, and a specific processing device can be designed or selected according to the technological description.

Specifically, an embodiment of the application provides an LNG cryogenic hose body and a forming process, mainly comprising: the method comprises the steps of (1) a sealing layer forming process, (2) a filling layer forming process, (3) an armor layer forming process, (4) a cold insulation layer forming process, (5) a leakage monitoring layer forming process, (6) an outer protective layer forming process and (7) a joint forming process. The specific scheme is as follows:

(1) Sealing layer forming process

The sealing layer of the hose structure adopts a seamless corrugated pipe, and single-section seamless corrugated pipes are connected through a welding process.

The sealing layer forming process of one embodiment comprises the following steps:

spinning 304 seamless steel tube or 306 seamless steel tube, ripple forming, argon arc welding and welding performance detection.

Wherein, "spin 304 seamless steel tube or 306 seamless steel tube": the method specifically comprises the steps of carrying out spinning cogging treatment for 1 time, carrying out vacuum annealing heat treatment for 1 time, carrying out spinning thinning forming for 4 times, and finally carrying out vacuum solution heat treatment.

The cogging treatment mainly aims at finishing the surface quality and the relevant size of a blank, ensuring that the material can have a good flowing state during the subsequent spinning with large deformation, and being beneficial to ensuring the dimensional accuracy of a final product.

The vacuum annealing heat treatment is commonly called as softening treatment, and aims to eliminate material work hardening caused by spinning deformation.

And 4 times of spinning thinning forming, namely, finally thinning forming the thick-wall stainless steel pipe to a target size through reasonable distribution of deformation. The overall thinning rate must not exceed the ultimate thinning rate of the material.

The vacuum solution heat treatment is carried out after all the passes of spin forming are finished, and the aim is to improve the microstructure and mechanical properties of the material. After solution treatment, compared with the performance of non-solution treatment after spinning, the strength of the material is reduced, but the plasticity is obviously improved, and the comprehensive performance is greatly improved compared with that of the traditional corrugated pipe.

After corrugation, the effective length of the product is about one third of the original length. Wave height 15-19mm, wave distance 12-13mm, wall thickness 0.6-1.0mm (the structure can be adjusted according to practical application working conditions).

"argon arc welding": in practical application, a plurality of single-section corrugated pipes can be welded into required lengths according to working conditions. When the corrugated pipe is welded, the corrugated pipe end face is disconnected on an inner wave crest when being aligned, then the vertical plane of the wave crest is ground flat, two sections (shown in figure 2) are aligned when being welded, namely the planes of a first section 1 and a second section 2, and then the position of an outer wave crest R angle 3 is welded, as shown in figure 3.

The welding performance detection only evaluates the air tightness of the welding seam, and does not need to press and detect the strength of the welding seam so as to avoid the influence of instability and deformation of the corrugated pipe on the service performance of the corrugated pipe, and the specific operation of the air tightness detection is as follows: the soaking experiment under the inflation state of the corrugated pipe is performed after flanges 24 are welded at two ends of the corrugated pipe, inflation parameters can be executed according to industry standards, the gas pressure is about 0.2MPa, and the pressure is maintained for about 3 minutes.

When the outer layers of the corrugated pipe are processed, the processed prefabricated inner core 5 of the end joint is welded on the corrugated pipe in advance. The welding process is similar to the corrugated tube peak welding process, and the prefabricated core welds 4 are shown in fig. 4. And (5) performing hydrostatic test after the joint is welded.

(2) Filling layer forming process

And (3) processing a filling layer, namely fixing the prefabricated low-temperature-resistant corrugated polyolefin foam tape 6 on a corrugated pipe, and then winding and fixing the polyolefin foam tape 6 on the corrugated pipe by using 80X0.2mm (width X thickness) glass fiber tape through a winding process by using a two-disc winding machine, wherein the winding process is shown in fig. 5.

(3) Armor layer forming process

When the armor layer is used as a tensile layer, firstly, the processed 25mm (width-adjustable) X2mm (thickness-adjustable) aramid braid is wound on a wire coil by a tape-bonding machine, and the total number of the wires is 24. And then the first twisting body 12 disc and the second twisting body 12 disc of the winding machine are respectively arranged on the winding machine, the tension of each disc is adjusted to be 80-100N, each disc is connected to a wire outlet hole and is respectively pulled on a wire outlet wheel, and each aramid fiber belt is fixed on the corrugated pipe prefabricated inner core. Starting the main machine, and winding by an axial winding angle of 20-25 degrees. And finally, according to the length of the pipe body designed in advance, winding the aramid fiber belt on a joint with a prefabricated tail end, and preparing for processing in the next working procedure after fixing.

The winding machine can adopt two sets of cage angle winding machines 13, one set of belt covering traction machine and two sets of 9.5 m idler wheels 12. An armor winding machine is schematically illustrated in fig. 7.

(4) Cold insulation layer forming process

The cold insulation layer can be made of air-setting adhesive tape, the specification of the adhesive tape is 5-10mm thick and 100mm wide, and the adhesive tape is formed by a double-layer tape winding machine, and then is wound and fixed by glass fiber tapes, and two layers are formed at a time. The number of windings can be determined according to the design thickness, and the tension at the time of winding is not lower than 50N. The cold insulation winding machine production line is schematically shown in fig. 8, and comprises cold insulation winding rollers 14 positioned at two sides, a double-layer tape winding machine 15 in the middle and a glass fiber tape winding machine 16.

(5) Leakage monitoring layer forming process

The low-temperature-resistant armored sensing optical cable is wound and laid, 1-2 core sensing optical fibers 7 are arranged in the low-temperature-resistant armored sensing optical cable, the outside of the optical fibers 7 is sequentially protected by stainless steel spiral tubes 9, high-modulus Kevlar aramid yarns (reinforcing pieces 8), stainless steel woven meshes 10 and special plastic outer jackets 11, the optical cable laying mode is preferably spirally distributed and laid between two cold insulation layers (namely, the optical cable laying mode is laid outside a certain cold insulation layer in a spiral winding mode). The cable structure is shown in fig. 6.

(6) Forming process of outer protective layer

The outer protective layer can adapt to the requirements of working conditions according to different design materials such as CPE (chlorinated polyethylene), HDPE (high density polyethylene), PA11 (nylon-11), TPU (polyether material), PVC (polyvinyl chloride), PE (polyethylene) and the like, and an extruder with the same specification is selected to extrude and cover the pipe body. Care should be taken in the extrusion process to control the temperature characteristics of the extruded polymeric material and to cool it, avoiding extrusion defects. The production line of the extruder for the outer protective layer is schematically shown in fig. 9, and mainly comprises an extruder 17, a water tank 18 and a tractor 19 which are sequentially arranged.

(7) End joint forming and mounting process

The processing of the joint is performed simultaneously with the processing of the functional layers.

After the welding of the prefabricated core 5 is completed, the machined female ring 20 is welded to the outside of the prefabricated core 5.

After the armor is processed, the processed convex ring 21 is sleeved on the aramid fiber woven belt through a buckling press, and the convex ring 21 is buckled and pressed at the corresponding position of the concave ring 20 through a buckling and pressing die, so that back locking is realized. The aramid fiber braid cannot be blocked during buckling, and the buckling pressure is generally not more than 5Mpa.

After the armor layer is buckled, the cold insulation layer is processed.

After the cold insulation layer is processed, the prefabricated inner support sleeve 22 is buckled on the cold insulation layer through a buckling machine. The inner support sleeve 22 is welded and fixed with the prefabricated inner core 5. One end of the inner support sleeve 22 is reserved with an optical cable threading opening.

After the inner support sleeve 22 is buckled and welded, the outer protective layer is processed.

After the outer protective layer is processed, the prefabricated joint outer skin 23 is buckled on the outer protective layer through a buckling machine.

After the crimping of the joint skin 23, the flange 24 is welded to the preformed core. Finally, hydrostatic test is carried out, the test pressure is not more than 1.5 times of the design pressure, and the buckling can be carried out in a hydraulic driving mode. The joint processing schematic diagram is shown in fig. 10.

The materials or parameters in the above embodiments of the present application may be adjusted as desired. The processing apparatus in the above embodiment may be implemented by using the prior art, and will not be described herein.

By adopting the scheme, the low-temperature hose with low temperature resistance of-196 ℃, pressure resistance of not less than 1.2MPa, bending radius of not more than 10 times of the inner diameter of the hose, good low-temperature resistance, stable pressure bearing capacity and high flexibility can be obtained.

Aiming at the critical problem that the processing technology and method of the existing LNG low-temperature conveying system are lack of the industry to be solved urgently, the inventor puts forward the processing technology of the LNG low-temperature hose by virtue of experience and practice of relevant industries engaged for many years, fills the blank of the prior art, and solves the critical problem of the industry.

It should be noted that, in this document, the terms "center", "upper", "lower", "left", "right", "vertical", "horizontal", "inner", "outer", etc. indicate orientations or positional relationships based on those shown in the drawings, and are merely for convenience in describing the present application and simplifying the description, and do not indicate or imply that the system or element to be referred to must have a specific orientation, be configured and operated in a specific orientation, and thus should not be construed as limiting the present application; relational terms such as "first" and "second", and the like may be used solely to distinguish one entity or action from another entity or action without necessarily requiring or implying any actual such relationship or order between such entities or actions. Moreover, the terms "comprises," "comprising," or any other variation thereof, are intended to cover a non-exclusive inclusion, such that a process, method, article, or apparatus that comprises a list of elements does not include only those elements but may include other elements not expressly listed or inherent to such process, method, article, or apparatus. Without further limitation, an element defined by the phrase "comprising one … …" does not exclude the presence of other like elements in a process, method, article, or apparatus that comprises the element.

Furthermore, in the description of the present application, it should be noted that, unless explicitly specified and limited otherwise, the terms "mounted," "connected," and "connected" are to be construed broadly, and may be either fixedly connected, detachably connected, or integrally connected, for example; can be mechanically or electrically connected; can be directly connected or indirectly connected through an intermediate medium, and can be communication between two elements. The specific meaning of the above terms in the present application will be understood in specific cases by those of ordinary skill in the art.

The foregoing embodiments are merely illustrative of the application, and various components and arrangements of the embodiments may be varied, and various implementations may be combined or omitted as desired, and not all of the components in the drawings are necessarily arranged, as the general principles defined herein may be implemented in other embodiments without departing from the spirit or scope of the application. Therefore, the present application should not be limited to the embodiments described herein, and all equivalent changes and modifications made on the basis of the technical solutions of the present application should not be excluded from the protection scope of the present application.

Claims

1. A method of forming an LNG cryogenic hose body, the method comprising:

the outer protective layer of the outermost layer of the pipe body is formed by extruding and coating the secondary outer layer of the pipe body;

the forming of the corrugated pipe after the spinning thinning of the seamless steel pipe further comprises the following steps:

welding a plurality of single-section corrugated pipes into required lengths through argon arc welding, evaluating the air tightness of welding seams, firstly disconnecting the end faces of adjacent welded corrugated pipes at inner wave crests, then grinding the vertical faces of the wave crests to be flat, aligning the plane at two ends during welding, and then welding the R angle of an outer wave crest, wherein the R angle is an arc angle corresponding to the wave crest or the wave trough;

the leak-monitoring layer formation includes:

the low-temperature-resistant armored sensing optical cable is wound and laid, the low-temperature-resistant armored sensing optical cable comprises built-in 1-2 core sensing optical fibers, the outside of the sensing optical fibers is sequentially protected by stainless steel spiral tubes, high-modulus Kevlar aramid yarns, woven nets and special plastic outer jackets, and the optical cable laying mode adopts spiral arrangement and is laid between certain two cold insulation layers.

2. The LNG cryogenic hose body forming method of claim 1, wherein spin-thinning the seamless steel pipe comprises:

3. The LNG cryogenic hose body forming method according to claim 1 or 2, wherein forming the seamless steel pipe into a corrugated pipe after spin-thinning comprises: after the spinning process, a vacuum solution heat treatment is performed.

4. A method of forming a LNG cryogenic hose body according to claim 3, wherein the wave height is 15-19mm, the wave pitch is 12-13mm and the wall thickness is 0.6-1.0mm when forming the corrugated pipe.

5. The method for forming an LNG low temperature hose body according to claim 1, 2 or 4, wherein the armor layer is formed by two layers of reverse winding with aramid webbing by a winding machine, the winding tension is 80-100N, the axial winding angle is 20 ° -25 °, and the thickness of each layer of aramid webbing is 1-2mm.

6. The LNG cryogenic hose pipe forming method according to claim 1, 2 or 4, wherein the cold insulation layer is wound comprising: and winding by adopting an aerogel tape, wherein the tension is not lower than 50N during winding.

7. The method for forming an LNG low temperature hose body according to claim 1, 2 or 4, wherein the outer protective layer is extrusion-formed using any one of chlorinated polyethylene, nylon-11, polyether material, polyvinyl chloride, polyethylene;

the thickness of the outer protective layer is 10mm, and the deviation between the upper and lower parts is +/-0.5 mm.

8. The LNG cryogenic hose body forming process of claim 7, further comprising an end fitting forming and installing process comprising: welding a concave ring outside a prefabricated inner core of a pipe body, sleeving a convex ring on an armor layer through buckling and pressing, and buckling and pressing the convex ring at a position corresponding to the concave ring, so that the concave ring and the convex ring are reversely locked, and the buckling and pressing pressure is not more than 5Mpa; the prefabricated inner support sleeve is buckled on the cold insulation layer in a buckling mode, the inner support sleeve and the prefabricated inner core are welded and fixed, and an optical cable penetrating port is reserved at one end of the inner support sleeve; the prefabricated joint outer skin is buckled and pressed on the outer protective layer; then welding a flange on the prefabricated inner core; and then, carrying out hydrostatic test, wherein the test pressure is not more than 1.5 times of the design pressure.