阅读说明：本技术 一种lng低温预制保冷管及其制造方法 (LNG low-temperature prefabricated cold insulation pipe and manufacturing method thereof ) 是由 郭宏新 张由素 吴然 刘艳平 于 2020-06-12 设计创作，主要内容包括：本发明公开了一种LNG低温预制保冷管及其制造方法,该低温预制管由内至外依次为工作管、保冷层和外护层；其中,保冷层采用至少1层PIR泡沫形成PIR保冷层,每层PIR泡沫外均设置防潮层,外护层采用紫外线硬化玻璃钢；其中保冷层采用整体预制的PIR结构,材料利用率从60%提高到90%,结构拼缝减少90%以上,胶类产品使用量减少70%,采用紫外线固化玻璃钢完全无接缝外护,抗踩踏、抗紫外线、抗盐雾腐蚀,综合性能大幅提高；85%保冷工作在预制车间完成,现场施工量降低到15%,提高保冷质量、施工效率,降低现场安全隐患,保证项目工期,成本较传统保冷系统节省20%以上。(The invention discloses an LNG low-temperature prefabricated cold insulation pipe and a manufacturing method thereof, wherein the low-temperature prefabricated pipe sequentially comprises a working pipe, a cold insulation layer and an outer protective layer from inside to outside; the cold insulation layer is formed by at least 1 layer of PIR foam, a moisture-proof layer is arranged outside each layer of PIR foam, and the outer protective layer is made of ultraviolet hardened glass fiber reinforced plastic; the cold insulation layer adopts an integrally prefabricated PIR structure, the material utilization rate is improved to 90% from 60%, the structural joint is reduced by more than 90%, the usage amount of glue products is reduced by 70%, the ultraviolet curing glass fiber reinforced plastics are adopted to completely protect the glue products without seams, the trample resistance, the ultraviolet resistance and the salt mist corrosion resistance are realized, and the comprehensive performance is greatly improved; 85% of cold insulation work is finished in a prefabricating workshop, the field construction amount is reduced to 15%, the cold insulation quality and the construction efficiency are improved, the potential safety hazard on the field is reduced, the project construction period is ensured, and the cost is saved by more than 20% compared with the traditional cold insulation system.)

1. The LNG low-temperature prefabricated cold insulation pipe is characterized in that the cold insulation pipe sequentially comprises a working pipe, a cold insulation layer and an outer protective layer from inside to outside; wherein, cold insulation layer adopts 1 at least layer PIR foam to form PIR cold insulation layer, all sets up the dampproof course outside every layer PIR foam, and the outer jacket adopts ultraviolet hardening glass steel.

2. The LNG low-temperature prefabricated cold insulation pipe as claimed in claim 1, wherein the two ends of the working pipe, the cold insulation layer, the moisture-proof layer and the outer protective layer are distributed in a step shape.

3. An LNG low-temperature prefabricated cold insulation pipe as claimed in claim 1, characterized in that the formed PIR foam is of a tubular structure, the thickness of a single layer is 50-80 mm, the length of the formed PIR foam is matched with that of the working pipe, and 1-3 layers of PIR pipe shells are sleeved together to form a PIR cold insulation layer with the total thickness of about 50-200 mm.

4. An LNG low-temperature prefabricated cold insulation pipe according to any one of claims 1 to 3, characterized in that the cold insulation layer is sleeved outside the working pipe in a layered mode, the step width is 50mm plus or minus 5mm, and the exposed length of the working pipe at the two ends of the cold insulation layer is 250mm plus or minus 10 mm.

5. The LNG low-temperature prefabricated cold-insulation pipe as claimed in claim 1, wherein the moisture-proof layer is a PAP aluminum foil, the thickness of the PAP aluminum foil is 1mm, the width of the PAP aluminum foil is 1m, the PAP aluminum foil is arranged on the outer surface of each layer of PIR after being cut, the aluminum foil layer faces outwards, and the overlapping length of adjacent PAP aluminum foils is not less than 40 mm.

6. The LNG low-temperature prefabricated cold insulation pipe as claimed in claim 1, wherein the common pipe diameter of the ultraviolet-cured glass fiber reinforced plastic pipe is DN 200-DN 600, and the thickness of the ultraviolet-cured glass fiber reinforced plastic pipe is 6-10 mm.

7. The LNG low-temperature prefabricated cold-insulation pipe as claimed in claim 1 or 6, wherein the outer protective layer is formed by processing a resin matrix, a continuous glass fiber and a fabric as reinforcing materials through a computer-controlled winding process.

8. The manufacturing method of the LNG low-temperature prefabricated cold insulation pipe as claimed in claim 1, characterized in that the manufacturing method is carried out by adopting a special equipment production method, and the specific steps are as follows:

(1) installing the surface-treated working pipe on a workbench, wherein the working pipe can rotate on the workbench at a constant speed along the axial direction, and the rotating speed is 20-40 r/min;

(2) pouring A, B composite material prepared in advance onto the surface of a working pipe by a polyurethane pouring machine to form a polyurethane cold insulation layer, enabling a nozzle of the pouring machine to axially move along the working pipe at a moving speed of 0.01-0.05 m/s, and enabling the discharge amount of an injection port to be 1.5-2 × 10^-6m³/s；

(3) Carrying out surface rolling treatment on the PIR cold insulation layer to ensure that the surface of the cured cold insulation layer is smooth and flat;

(4) cutting the moisture-proof layer and then pasting the moisture-proof layer on the outer surface of the PIR cold insulation layer, wherein the joint meets the lap joint requirement;

(5) then, according to the processing method in the step (2), pouring a second cold insulation layer on the outer surface of the first cold insulation layer, and paying attention to the step-shaped control of the two ends;

(6) repeating the step (3) and the step (4) until all the cold insulation layers and the moisture-proof layers are prefabricated;

(7) processing an ultraviolet-cured glass fiber reinforced plastic outer protective layer outside the cold insulation layer by using a glass fiber reinforced plastic winding machine;

(8) after the outer glass fiber reinforced plastic protective layer is cured, taking down the prefabricated heat-preservation pipe from the workbench, and placing the pipe on a flat ground for natural maintenance;

(9) and finally, carrying out damp-proof and waterproof sealing treatment on the two ends of the prefabricated pipe by using a PE film or a sealing adhesive tape.

9. The manufacturing method of the LNG low-temperature prefabricated cold insulation pipe as claimed in claim 1, characterized in that a special mold production method is adopted for production, and the specific steps are as follows:

(1) preparing an annular cylindrical mold with a standard pipe diameter, and coating a release agent in the mold;

(2) pouring the prepared A, B combined material into an annular cylindrical die at the material pouring speed of 0.01-0.03 m/s, and demolding after curing and forming to prefabricate an inner PIR cold insulation layer of a tubular structure;

(3) repeating the step (1) and the step (2), and prefabricating other PIR cold insulation layers in the matched mould;

(4) cutting the moisture-proof layer and then pasting the moisture-proof layer on the outer surface of the PIR cold insulation layer, wherein the joint meets the lap joint requirement;

(5) sleeving the PIR cold insulation material subjected to veneering treatment outside the working pipe layer by layer, and controlling the two ends in a step shape;

(6) processing ultraviolet-cured glass fiber reinforced plastics outside the cold insulation layer by a glass fiber reinforced plastic winding machine;

(7) after the outer glass fiber reinforced plastic protective layer is cured, taking down the prefabricated heat-preservation pipe from the workbench, and placing the pipe on a flat ground for natural maintenance;

(8) and finally, carrying out damp-proof and waterproof sealing treatment on the two ends of the prefabricated pipe by using a PE film or a sealing adhesive tape.

10. The manufacturing method of the LNG low-temperature prefabricated cold-insulation pipe as claimed in claim 8 or 9, wherein the volume ratio of the A combined material to the B combined material is 1: 1-1.5; the composite material A comprises polyether, polyester polyol and various auxiliaries, wherein the auxiliaries comprise one or more foaming agents, foam stabilizers, catalysts and flame retardants; the composition material B is isocyanate.

Technical Field

The invention relates to a pipeline cold insulation technology in the field of low-temperature medium conveying, in particular to an LNG low-temperature prefabricated cold insulation pipe and a manufacturing method thereof.

Background

In recent years, the nation has vigorously advocated energy conservation and emission reduction, and encourages the use of clean energy, the combustion of natural gas is cleaner than that of combustion products of coal, and the energy occupation ratio of Liquefied Natural Gas (LNG) is higher and higher. Common cold insulation materials for cold insulation of LNG pipelines are Polyurethane (PIR), foam glass FG or a composite of the polyurethane and the foam glass FG, and the technology mainly has the following problems: 1) the cutting and forming material of the PIR and FG prefabricated pipe shell has high loss rate, the utilization rate is only 55-60 percent, the waste is difficult to treat, and the pressure is caused to health, safety and environment; 2) the prefabricated pipe shell-shaped bonding joint has more joints and auxiliary materials, the construction is complicated, and the construction quality and the construction period are uncontrollable; 3) the cold insulation structure has more joints, and condensation, freezing and cold energy loss are easy to occur in later operation; 4) the foam block material has large volume, low density, high overall cost caused by complex transportation, storage and construction, many auxiliary materials and the like; 5) the sealant and the cold insulation glue are chemicals, and have harsh transportation and storage conditions and are not good for health, safety and environment; 6) the outer protective layer is made of metal materials, and the protective layer is easily corroded and damaged in a humid and rainy seaside area to cause the problems of failure in protection and the like.

Disclosure of Invention

Aiming at the defects of the prior problems, the invention aims to provide an LNG low-temperature prefabricated cold-insulation pipe and a manufacturing method thereof. The low-temperature prefabricated cold insulation pipe has a simple structure, and the cold loss is small and is reduced by 30% compared with the traditional structure; and the material loss rate is low, the automation degree is high, the auxiliary material amount is small, the construction period can be greatly shortened, the total cost is reduced, and the comprehensive performance is greatly improved.

The technical scheme adopted by the invention for solving the technical problems is as follows:

an LNG low-temperature prefabricated cold insulation pipe comprises a working pipe, a cold insulation layer and an outer protective layer from inside to outside in sequence; wherein, cold insulation layer adopts 1 at least layer PIR foam to form PIR cold insulation layer, all sets up the dampproof course outside every layer PIR foam, and the outer jacket adopts ultraviolet hardening glass steel. The structures are prefabricated in a factory, only a small amount of joint repairing operation is needed on a construction site, the integral cold insulation effect of the low-temperature prefabricated pipe meets the anti-condensation requirement, and the maximum cold loss is not more than 25W/m²The requirements of (1).

Preferably, the working pipe, the cold insulation layer, the moisture-proof layer and the two end parts of the outer protective layer are distributed in a step shape, so that staggered joints of cold insulation materials at joints are conveniently lapped, and reduction of cold loss is facilitated.

Preferably, the formed PIR foam is of a tubular structure, the thickness of a single layer is 50-80 mm, the length of the single layer is matched with that of a working pipe, 1-3 layers of PIR pipe shells are sleeved together to form a PIR cold insulation layer with the total thickness of about 50-200 mm, cold insulation materials are arranged in a layered mode, the arrangement of a moisture-proof layer is facilitated, and the multiple layers of moisture-proof layers can effectively reduce rainwater immersion and protect the cold insulation materials; the more important cold insulation materials are arranged in a layered mode, so that the pipeline heat displacement can be absorbed, the inner layer cold insulation materials are consistent with the pipeline heat displacement, and the pipeline cold insulation materials are not torn.

Preferably, the cold insulation layer is sleeved outside the working pipe in a layered mode, the step width is 50 +/-5 mm, the exposed length of the working pipe at the two ends of the cold insulation layer is 250 +/-10 mm, and the on-site joint coating operation is facilitated.

Preferably, the dampproof course be the PAP aluminium foil, the thickness of PAP aluminium foil is 1mm, and the width is 1m, sets up in the surface of every layer of PIR after cutting out, and the aluminium foil layer is outwards, and adjacent PAP aluminium foil's overlap joint length is no less than 40 mm.

Preferably, each layer of PIR cold insulation layer is provided with a PAP moisture-proof layer, the outer surface of the PAP coiled material is a front surface, and the front surface is required to be outward when the PAP coiled material is used, otherwise, the service life is influenced.

Preferably, the common pipe diameter of the ultraviolet-cured glass steel pipe is DN 200-DN 600, the thickness of the ultraviolet-cured glass steel pipe is 6-10 mm, and the glass steel pipe is used as an outer protective layer, so that the mechanical strength is high, and the corrosion resistance is good.

Preferably, the outer protective layer is formed by processing a resin serving as a matrix and continuous glass fibers and fabrics serving as reinforcing materials through a computer-controlled winding process.

A manufacturing method of an LNG low-temperature prefabricated cold insulation pipe is manufactured by adopting a special equipment production method and comprises the following specific steps:

(1) installing the surface-treated working pipe on a workbench, wherein the working pipe can rotate on the workbench at a constant speed along the axial direction, and the rotating speed is 20-40 r/min;

(2) pouring A, B composite materials (the volume ratio of the material A to the material B is 1 (1-1.5)) which are prepared in advance into the surface of a working pipe by means of a polyurethane pouring machine, wherein the material A is polyether, polyester polyol and various auxiliaries, the auxiliaries comprise one or more foaming agents, foam stabilizers, catalysts and flame retardants, and the material B is isocyanate to form a polyurethane cold insulation layer, a nozzle of the pouring machine axially moves along the working pipe at the moving speed of 0.01-0.05 m/s, and the discharge amount of an injection port is 1.5-2 × 10^-6m³/s；

(3) Carrying out surface rolling treatment on the polyurethane cold insulation layer to ensure that the surface of the cured cold insulation layer is smooth and flat;

(4) cutting the moisture-proof layer and then pasting the moisture-proof layer on the outer surface of the PIR cold insulation layer, wherein the joint meets the lap joint requirement;

(5) then, according to the processing method in the step (2), pouring a second cold insulation layer on the outer surface of the first cold insulation layer, and paying attention to the step-shaped control of the two ends;

(6) repeating the step (3) and the step (4) until all the cold insulation layers and the moisture-proof layers are prefabricated;

(7) processing an ultraviolet-cured glass fiber reinforced plastic outer protective layer outside the cold insulation layer by using a glass fiber reinforced plastic winding machine;

(8) after the outer glass fiber reinforced plastic protective layer is cured, taking down the prefabricated heat-preservation pipe from the workbench, and placing the pipe on a flat ground for natural maintenance;

(9) and finally, carrying out damp-proof and waterproof sealing treatment on the two ends of the prefabricated pipe by using a PE film or a sealing adhesive tape.

A manufacturing method of an LNG low-temperature prefabricated cold insulation pipe adopts a special die production method to produce, and comprises the following specific steps:

(1) preparing an annular cylindrical mold with a standard pipe diameter, and coating a release agent in the mold;

(2) the prepared A, B composite material (the volume ratio of the material A to the material B is 1 (1-1.5), wherein the material A is polyether, polyester polyol and a plurality of auxiliary agents, the auxiliary agents comprise one or more foaming agents, foam stabilizers, catalysts and flame retardants, and the material B is isocyanate) is mixed according to the proportion of 0.01-0.03m³Pouring the mixture into an annular cylindrical mold at a material injection speed/s, curing and molding, and demolding to prefabricate an inner-layer PIR cold insulation layer of a tubular structure;

(3) repeatedly performing the step (1) and the step (2) to prefabricate other PIR cold insulation layers in the matched mould;

(4) cutting the moisture-proof layer and then pasting the moisture-proof layer on the outer surface of the PIR cold insulation layer, wherein the joint meets the lap joint requirement;

(5) sleeving the PIR cold insulation material subjected to veneering treatment outside the working pipe layer by layer, and paying attention to step-shaped control at two ends;

(6) processing a hard glass fiber reinforced plastic outer protective layer outside the cold insulation layer by a glass fiber reinforced plastic winding machine;

(7) after the outer glass fiber reinforced plastic protective layer is cured, taking down the prefabricated heat-preservation pipe from the workbench, and placing the pipe on a flat ground for natural maintenance;

(8) and finally, carrying out damp-proof and waterproof sealing treatment on the two ends of the prefabricated pipe by using a PE film or a sealing adhesive tape.

Preferably, the foaming process for PIR is shown in FIG. 1.

Preferably, the density of the PIR foam is controlled to be 50 +/-5 kg/m3, the thermal conductivity coefficient is less than or equal to 0.02W/m.k, the oxygen index reaches 30, the combustion grade is B1 grade, and the compression strength is more than or equal to 230 Kpa.

Advantageous effects

According to the LNG low-temperature prefabricated cold insulation pipe and the manufacturing method thereof, the integrally prefabricated PIR structure is adopted, the material utilization rate is improved to 90% from 60%, the structural joint is reduced by more than 90%, the usage amount of glue products is reduced by 70%, the ultraviolet curing glass fiber reinforced plastics are used for completely protecting without seams, trampling resistance, ultraviolet resistance and salt mist corrosion resistance are achieved, and the comprehensive performance is greatly improved; 85% of cold insulation work is finished in a prefabricating workshop, the field construction amount is reduced to 15%, the cold insulation quality and the construction efficiency are improved, the potential safety hazard on the field is reduced, the project construction period is ensured, and the cost is saved by more than 20% compared with the traditional cold insulation system.

Drawings

FIG. 1 shows a process for foaming PIR;

FIG. 2 is a cross-sectional view of a low temperature prefabricated cold insulation pipe;

FIG. 3 is a partially enlarged cross-sectional view of a low-temperature prefabricated cold insulation pipe;

FIG. 4 is a schematic view of a low temperature prefabricated cold insulation pipe structure;

in the figure: 1-a working pipe; 2-a moisture barrier; 3-cold insulation layer; 4-outer protective layer.

Detailed Description

The present invention will be described in further detail with reference to examples. The reagents or instruments used are not indicated by manufacturers, and are regarded as conventional products which can be purchased in the market.