CN111720630A - LNG low-temperature prefabricated cold insulation pipe and manufacturing method thereof - Google Patents

LNG low-temperature prefabricated cold insulation pipe and manufacturing method thereof Download PDF

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Publication number
CN111720630A
CN111720630A CN202010533963.3A CN202010533963A CN111720630A CN 111720630 A CN111720630 A CN 111720630A CN 202010533963 A CN202010533963 A CN 202010533963A CN 111720630 A CN111720630 A CN 111720630A
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CN
China
Prior art keywords
cold insulation
pipe
layer
pir
prefabricated
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CN202010533963.3A
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Chinese (zh)
Inventor
郭宏新
张由素
吴然
刘艳平
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Jiangsu Sunpower Piping Technology Co ltd
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Jiangsu Sunpower Piping Technology Co ltd
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Priority to CN202010533963.3A priority Critical patent/CN111720630A/en
Publication of CN111720630A publication Critical patent/CN111720630A/en
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    • F—MECHANICAL ENGINEERING; LIGHTING; HEATING; WEAPONS; BLASTING
    • F16—ENGINEERING ELEMENTS AND UNITS; GENERAL MEASURES FOR PRODUCING AND MAINTAINING EFFECTIVE FUNCTIONING OF MACHINES OR INSTALLATIONS; THERMAL INSULATION IN GENERAL
    • F16L—PIPES; JOINTS OR FITTINGS FOR PIPES; SUPPORTS FOR PIPES, CABLES OR PROTECTIVE TUBING; MEANS FOR THERMAL INSULATION IN GENERAL
    • F16L9/00—Rigid pipes
    • F16L9/14—Compound tubes, i.e. made of materials not wholly covered by any one of the preceding groups
    • B—PERFORMING OPERATIONS; TRANSPORTING
    • B29—WORKING OF PLASTICS; WORKING OF SUBSTANCES IN A PLASTIC STATE IN GENERAL
    • B29C—SHAPING OR JOINING OF PLASTICS; SHAPING OF MATERIAL IN A PLASTIC STATE, NOT OTHERWISE PROVIDED FOR; AFTER-TREATMENT OF THE SHAPED PRODUCTS, e.g. REPAIRING
    • B29C39/00—Shaping by casting, i.e. introducing the moulding material into a mould or between confining surfaces without significant moulding pressure; Apparatus therefor
    • B29C39/02—Shaping by casting, i.e. introducing the moulding material into a mould or between confining surfaces without significant moulding pressure; Apparatus therefor for making articles of definite length, i.e. discrete articles
    • B29C39/021—Shaping by casting, i.e. introducing the moulding material into a mould or between confining surfaces without significant moulding pressure; Apparatus therefor for making articles of definite length, i.e. discrete articles by casting in several steps
    • B29C39/025—Shaping by casting, i.e. introducing the moulding material into a mould or between confining surfaces without significant moulding pressure; Apparatus therefor for making articles of definite length, i.e. discrete articles by casting in several steps for making multilayered articles
    • B—PERFORMING OPERATIONS; TRANSPORTING
    • B29—WORKING OF PLASTICS; WORKING OF SUBSTANCES IN A PLASTIC STATE IN GENERAL
    • B29C—SHAPING OR JOINING OF PLASTICS; SHAPING OF MATERIAL IN A PLASTIC STATE, NOT OTHERWISE PROVIDED FOR; AFTER-TREATMENT OF THE SHAPED PRODUCTS, e.g. REPAIRING
    • B29C39/00—Shaping by casting, i.e. introducing the moulding material into a mould or between confining surfaces without significant moulding pressure; Apparatus therefor
    • B29C39/02—Shaping by casting, i.e. introducing the moulding material into a mould or between confining surfaces without significant moulding pressure; Apparatus therefor for making articles of definite length, i.e. discrete articles
    • B29C39/10—Shaping by casting, i.e. introducing the moulding material into a mould or between confining surfaces without significant moulding pressure; Apparatus therefor for making articles of definite length, i.e. discrete articles incorporating preformed parts or layers, e.g. casting around inserts or for coating articles
    • B—PERFORMING OPERATIONS; TRANSPORTING
    • B29—WORKING OF PLASTICS; WORKING OF SUBSTANCES IN A PLASTIC STATE IN GENERAL
    • B29C—SHAPING OR JOINING OF PLASTICS; SHAPING OF MATERIAL IN A PLASTIC STATE, NOT OTHERWISE PROVIDED FOR; AFTER-TREATMENT OF THE SHAPED PRODUCTS, e.g. REPAIRING
    • B29C69/00—Combinations of shaping techniques not provided for in a single one of main groups B29C39/00 - B29C67/00, e.g. associations of moulding and joining techniques; Apparatus therefore
    • F—MECHANICAL ENGINEERING; LIGHTING; HEATING; WEAPONS; BLASTING
    • F16—ENGINEERING ELEMENTS AND UNITS; GENERAL MEASURES FOR PRODUCING AND MAINTAINING EFFECTIVE FUNCTIONING OF MACHINES OR INSTALLATIONS; THERMAL INSULATION IN GENERAL
    • F16L—PIPES; JOINTS OR FITTINGS FOR PIPES; SUPPORTS FOR PIPES, CABLES OR PROTECTIVE TUBING; MEANS FOR THERMAL INSULATION IN GENERAL
    • F16L58/00—Protection of pipes or pipe fittings against corrosion or incrustation
    • F16L58/02—Protection of pipes or pipe fittings against corrosion or incrustation by means of internal or external coatings
    • F—MECHANICAL ENGINEERING; LIGHTING; HEATING; WEAPONS; BLASTING
    • F16—ENGINEERING ELEMENTS AND UNITS; GENERAL MEASURES FOR PRODUCING AND MAINTAINING EFFECTIVE FUNCTIONING OF MACHINES OR INSTALLATIONS; THERMAL INSULATION IN GENERAL
    • F16L—PIPES; JOINTS OR FITTINGS FOR PIPES; SUPPORTS FOR PIPES, CABLES OR PROTECTIVE TUBING; MEANS FOR THERMAL INSULATION IN GENERAL
    • F16L59/00—Thermal insulation in general
    • F16L59/02—Shape or form of insulating materials, with or without coverings integral with the insulating materials
    • F16L59/028—Composition or method of fixing a thermally insulating material
    • F—MECHANICAL ENGINEERING; LIGHTING; HEATING; WEAPONS; BLASTING
    • F16—ENGINEERING ELEMENTS AND UNITS; GENERAL MEASURES FOR PRODUCING AND MAINTAINING EFFECTIVE FUNCTIONING OF MACHINES OR INSTALLATIONS; THERMAL INSULATION IN GENERAL
    • F16L—PIPES; JOINTS OR FITTINGS FOR PIPES; SUPPORTS FOR PIPES, CABLES OR PROTECTIVE TUBING; MEANS FOR THERMAL INSULATION IN GENERAL
    • F16L59/00—Thermal insulation in general
    • F16L59/02—Shape or form of insulating materials, with or without coverings integral with the insulating materials
    • F16L59/029—Shape or form of insulating materials, with or without coverings integral with the insulating materials layered
    • B—PERFORMING OPERATIONS; TRANSPORTING
    • B29—WORKING OF PLASTICS; WORKING OF SUBSTANCES IN A PLASTIC STATE IN GENERAL
    • B29L—INDEXING SCHEME ASSOCIATED WITH SUBCLASS B29C, RELATING TO PARTICULAR ARTICLES
    • B29L2023/00—Tubular articles
    • B29L2023/22—Tubes or pipes, i.e. rigid

Abstract

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.

Description

LNG low-temperature prefabricated cold insulation pipe and manufacturing method thereof
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.
Example 1:
as shown in fig. 2, the LNG low-temperature prefabricated cold insulation pipe comprises a working pipe 1, a moisture-proof layer 2, a cold insulation layer 3 and an outer protective layer 4, wherein the four structures are tightly attached without gaps between the layers; as shown in fig. 3, the moisture-proof layer 2 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 the adjacent PAP aluminum foil is not less than 40 mm; the working pipes 1 at the two ends of the cold insulation pipe are exposed outside, the exposed length is about 250mm, and the on-site joint coating operation is convenient; the multiple cold insulation layers 3 and the moisture-proof layers 2 are alternately distributed, the inner layer material protrudes out of the adjacent inner layer material to form a step-shaped joint, and the width of each step is 50 mm;
as shown in figure 4, the PIR foam after the cold insulation pipe is formed is of a tubular structure, the thickness of a single layer is 60mm, the length of the single layer is matched with that of the working pipe 1, and 2 layers of PIR pipe shells are sleeved together to form a PIR cold insulation layer with the total thickness of about 120 mm. The integrally prefabricated PIR structure has the advantages that the material utilization rate is improved to 90 percent from 60 percent, the structural joint seam is reduced by more than 90 percent, the usage amount of rubber products is reduced by 70 percent, and the PIR foam density is reducedControlling the concentration to be 50 +/-5 kg/m3The heat 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.
As shown in fig. 4, the outer protective layer 4 of the cold insulation pipe is made of ultraviolet-hardening glass fiber reinforced plastic, the spiral lines generated in the winding process of the glass fiber and the fabric can be clearly seen on the surface of the outer protective layer, the glass fiber reinforced plastic is tightly wound, certain fastening effect is achieved on the internal structure, and the integrity of the whole cold insulation structure is stronger.
Wherein, the common pipe diameter of the ultraviolet hardening glass steel pipe is DN500, and the thickness is 6 mm; the ultraviolet hardening glass steel tube has no seam to protect the outer, and has the advantages of trample resistance, ultraviolet resistance, salt mist corrosion resistance and greatly improved comprehensive performance.
Example 2
The manufacturing method of the LNG low-temperature prefabricated cold-insulation pipe of the embodiment 1 specifically includes the following two methods:
1. production method of special equipment
(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) the method is characterized in that A, B composite materials (the volume ratio of A material to B material is 1 (1-1.5) which are prepared in advance are poured onto the surface of a working pipe by means of a polyurethane pouring machine, wherein the A material is polyether, polyester polyol and various auxiliaries, the auxiliaries comprise one or more foaming agents, foam stabilizers, catalysts and flame retardants, and the B material is isocyanate, the formula can ensure that the density of the produced polyurethane cold insulation material is 50 +/-5 kg/m3, the heat conductivity coefficient is less than or equal to 0.02W/m.k, the oxygen index reaches 30, the combustion grade is B1 grade, the compression strength is more than or equal to 230 Kpa), so that a nozzle of the pouring machine moves axially along the working pipe, the moving speed is 0.01-0.05 m/s, and the discharge amount of a filling port is 1.5-2 × 10-6m3And/s, finally forming a polyurethane cold insulation layer with the thickness of 50mm on the working pipe;
(3) performing surface rolling treatment on the PIR layer to ensure that the surface of the cured cold insulation layer is smooth and flat;
(4) cutting a PAR aluminum foil moisture-proof layer, and then sticking the cut PAR aluminum foil moisture-proof layer on the outer surface of a PIR cold insulation layer, wherein the PAP aluminum foil surface faces outwards, and the joint meets the lapping 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) further processing an ultraviolet-cured glass fiber reinforced plastic outer protective layer outside the cold insulation layer by 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) finally, carrying out damp-proof and waterproof sealing treatment on two ends of the prefabricated pipe by using a PE film or a sealing adhesive tape;
(10) and (4) printing company nameplates and other marks on the surfaces of the prefabricated pipes.
2. Production method of special mould
(1) Preparing a series of annular cylindrical dies with standard pipe diameters, and coating a release agent in the dies;
(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) repeating the step (1) and the step (2), and prefabricating a second layer and a third layer of PIR cold insulation layer in a larger mould matched with the steps;
(4) cutting a PAR aluminum foil, and then pasting the cut PAR aluminum foil on the outer surface of a PIR cold insulation layer to ensure that the PAP aluminum foil faces outwards and the joint meets the lapping 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) further processing an ultraviolet-cured 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) finally, carrying out damp-proof and waterproof sealing treatment on two ends of the prefabricated pipe by using a PE film or a sealing adhesive tape;
(9) and (4) printing company nameplates and other marks on the surfaces of the prefabricated pipes.
This embodiment has explained a prefabrication technique of LNG cold insulation pipeline, solves cold insulation material loss rate height, piece many, auxiliary material volume is many, and the construction is complicated, quality uncontrollable scheduling problem. Except for a small amount of joint repairing work, project site construction is needed, and the rest 85% of cold insulation work is prefabricated in a workshop, so that the construction efficiency is improved, the potential safety hazard is reduced, the pollution to personnel and the environment is reduced, and the cost is saved by more than 20% compared with the traditional cold insulation system.
The protection of the present invention is not limited to the above embodiments. Variations and advantages that may occur to those skilled in the art may be incorporated into the invention without departing from the spirit and scope of the inventive concept and the scope of the appended claims is intended to be protected.

Claims (10)

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.
CN202010533963.3A 2020-06-12 2020-06-12 LNG low-temperature prefabricated cold insulation pipe and manufacturing method thereof Pending CN111720630A (en)

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Cited By (3)

* Cited by examiner, † Cited by third party
Publication number Priority date Publication date Assignee Title
CN113266712A (en) * 2021-05-25 2021-08-17 江苏中圣管道工程技术有限公司 Low-temperature cold insulation pipe structure prefabricated by spraying and winding method and manufacturing method thereof
CN114165681A (en) * 2021-11-26 2022-03-11 湖北三江航天江北机械工程有限公司 Cold insulation construction method for LNG duplex tube set
CN116066634A (en) * 2023-01-04 2023-05-05 江苏中圣管道工程技术有限公司 Detachable prefabricated heat preservation pipe

Cited By (3)

* Cited by examiner, † Cited by third party
Publication number Priority date Publication date Assignee Title
CN113266712A (en) * 2021-05-25 2021-08-17 江苏中圣管道工程技术有限公司 Low-temperature cold insulation pipe structure prefabricated by spraying and winding method and manufacturing method thereof
CN114165681A (en) * 2021-11-26 2022-03-11 湖北三江航天江北机械工程有限公司 Cold insulation construction method for LNG duplex tube set
CN116066634A (en) * 2023-01-04 2023-05-05 江苏中圣管道工程技术有限公司 Detachable prefabricated heat preservation pipe

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