Foamed glass structure for LNG pipeline and method for manufacturing the same

Abstract

This invention provides a thermal shock resistant foam glass structure for LNG pipelines and its preparation method. Through the interaction between the thermal shock resistant structure and high-density and low-density insulation layers, when temperatures are low, the water stored in the reservoir freezes and expands, compressing the end of the V-shaped support. This causes the spring sheet inside the buffer bladder to bend. When the spring sheet bends to its limit, it bends inward, generating vibrations that disrupt the stability of the supersaturated sodium acetate solution inside the buffer bladder, causing the solution to crystallize and release heat, thus buffering the external temperature difference. Similarly, when temperatures are high, the external heat is absorbed by the supersaturated sodium acetate solution inside the buffer bladder, gradually breaking the crystallization state and performing energy storage, ready for the next cycle. This mitigates the temperature difference changes on the outside of the LNG pipeline, preventing high-intensity thermal shocks that could exceed the yield strength of the LNG pipeline material and damage metal components, thereby improving its thermal shock resistance.

Description

Technical Field

[0001] This application relates to the field of foam glass, and in particular to a thermal shock resistant foam glass structure for LNG pipelines and its preparation method. Background Technology

[0002] Thermal shock refers to the rapid heating or cooling of an object, causing a large amount of heat exchange and a drastic temperature change within a short period of time. This results in impact thermal stress, a phenomenon known as thermal shock. When metallic materials are subjected to rapid heating and cooling, a large temperature difference is generated internally, leading to significant impact thermal stress. A large thermal shock can generate thermal stress exceeding the material's yield strength, causing damage to metallic components.

[0003] In the construction of liquefied natural gas (LNG) pipeline projects, the temperature of the LNG medium in the pipeline is extremely low (approximately -162℃), while the pipeline's operating environment often reaches 30-40℃. The significant temperature difference between the ambient temperature and the medium temperature necessitates high requirements for pipeline insulation. In LNG pipeline projects, insulation is typically achieved using inorganic materials such as foam glass and organic materials such as PIR or PUR, either as a single material.

[0004] Traditional foam glass uses only a single covering structure, which can still generate a large amount of heat exchange under extreme conditions, causing thermal shock damage to LNG pipelines. Its protective effect is insufficient to guarantee the safety of LNG pipelines. To address this issue, we propose a thermal shock resistant foam glass structure for LNG pipelines and its preparation method. Summary of the Invention

[0005] The purpose of this application is to design a foam glass structure that can maintain the thermal shock resistance of LNG pipelines under extreme temperature changes, so as to ensure that the thermal stress generated under extreme conditions does not exceed the yield limit of the LNG pipeline material, thereby improving its safety. Compared with the existing technology, this application provides a foam glass structure for LNG pipelines to prevent thermal shock. It consists of a high-density insulation layer and an outer protective layer that are sequentially wrapped on the LNG pipeline from the inside out. The high-density insulation layer includes a high-density outer layer and a high-density inner layer. A low-density insulation layer is bonded between the high-density outer layer and the high-density inner layer. The low-density insulation layer includes a low-density outer layer and a low-density inner layer. A thermal shock-resistant structure is bonded between the low-density outer layer and the low-density inner layer.

[0006] The thermal shock protection structure includes V-shaped supports evenly distributed at equal angles between the low-density outer layer and the low-density inner layer. A liquid reservoir is fixed between the tops of two adjacent V-shaped supports. A buffer is fixed inside the bottom V-shaped angle of the V-shaped supports. A spring sheet is also fixed inside the bottom V-shaped angle of the V-shaped supports. The spring sheet extends and seals inside the buffer.

[0007] The liquid storage bladder is filled with low-temperature crystalline liquid, and the buffer bladder is filled with phase change heat storage material.

[0008] Furthermore, the liquid filling the reservoir is water, and the phase change heat storage material filling the buffer bladder is a supersaturated sodium acetate solution.

[0009] Furthermore, both the high-density insulation layer and the low-density insulation layer are made of foam glass. The pore size of the foam pores in the high-density insulation layer is larger than that in the low-density insulation layer, and the distribution density of the foam pores in the high-density insulation layer is greater than that in the low-density insulation layer.

[0010] Furthermore, the outer protective layer is made of polyisocyanurate foam, and a high-density polyisocyanurate rigid sheath is fitted over the outer side of the outer protective layer.

[0011] Furthermore, each of the low-density outer layer and the low-density inner layer has an assembly groove on its opposite side, and the assembly groove matches the outer contour of the V-shaped bracket, the reservoir, and the buffer bladder.

[0012] Furthermore, glass connecting fibers are added during the preparation of the low-density insulation layer. The glass connecting fibers are used to increase the bonding strength between the low-density insulation layer and the high-density insulation layer and the thermal shock protection structure.

[0013] Furthermore, the V-shaped bracket is an elastic plastic structure, and the spring sheet bends when the V-shaped bracket is not under stress.

[0014] Furthermore, the elastic modulus at the connection point between the reservoir and the V-shaped support is greater than that of the rest of the reservoir.

[0015] A method for preparing a thermal shock resistant foam glass structure for LNG pipelines specifically includes the following steps:

[0016] S1. Clean the waste glass, dry it, and then ball mill the waste glass. Mix 40-60 parts waste glass powder, 10-15 parts carbon black, 5-10 parts aluminate, 5-10 parts expanded graphite, and 1-2 parts fluxing agent according to the mass ratio. After ball milling, drying, and sieving, the mixture is placed in a graphite crucible and melted. After melting, the mixture is water quenched. The water-quenched mixture is placed in a rotary drying oven to dry and then crushed to obtain basic glass powder.

[0017] S2. Take the basic glass powder, pass it through a 220-mesh sieve, and transfer it into a graphite crucible. Then add the foaming agent, foam stabilizer, and composite nucleating agent in sequence. Stir mechanically for 20 minutes to mix it evenly. Add it to a ball mill jar and ball mill for 20-40 minutes. Pass it through a 250-mesh standard sieve to obtain the batch material.

[0018] S3. Add industrial ethanol to the batch material, fill the batch material into the mold, spread it flat and compact it, with a thickness of 4cm-6cm, and finally transfer the mold into the foaming furnace to fire into foam glass.

[0019] S4. The prepared foam glass is divided into a high-density insulation layer and a low-density insulation layer according to the pore density. After assembling the thermal shock protection structure in the low-density insulation layer, the high-density insulation layer is glued to both sides of the low-density insulation layer to prepare the thermal shock protection foam glass structure for LNG pipelines.

[0020] Furthermore, if the finished product is a low-density insulation layer, then in step S3, glass connecting fibers need to be added to the batch material. The finished low-density insulation layer is divided into a partition assembly groove in the middle by wire cutting, and the low-density insulation layer is separated into a low-density outer layer and a low-density inner layer.

[0021] Compared to existing technologies, the advantages of this application are:

[0022] (1) Through the design of a double-layer high-density insulation layer and a double-layer low-density insulation layer, compared with the traditional single-layer insulation structure, it can perform multiple interval heat exchanges and step-by-step heat exchanges when the outside temperature changes drastically, so as to achieve the purpose of generating a small temperature difference inside the LNG pipe when it is subjected to rapid heating and cooling, effectively reducing the impact thermal stress.

[0023] (2) Through the design of the outer protective layer, the corrosion resistance and aging resistance of the foam glass structure are improved on the one hand, and the cooperation between the outer protective layer and the elastic V-shaped bracket is utilized on the other hand. When an external impact force is generated, the kinetic energy will be absorbed by the deformation of the outer protective layer and the V-shaped bracket, which can effectively protect the high-density insulation layer and the low-density insulation layer to prevent them from collapsing due to excessive impact force, thereby improving their service life and insulation performance.

[0024] (3) By using glass to connect the fiber, the bonding strength between the low-density insulation layer, the high-density insulation layer, and the thermal shock protection structure is effectively enhanced. It is less likely to delaminate under severe temperature differences, thus effectively improving the structural strength and increasing the service life.

[0025] (4) The present invention utilizes a thermal shock protection structure with a V-shaped support, a liquid storage bladder, a buffer bladder, and a spring sheet, in conjunction with the high-density insulation layer and the low-density insulation layer. In actual use, the high-density insulation layer and the low-density insulation layer are used for conventional insulation. When extreme temperature changes occur, such as at low temperatures, the water in the liquid storage bladder will expand when it freezes due to the low temperature, which will then compress the end of the V-shaped support. At this time, the V-shaped support is compressed and overcomes its own elastic deformation, which in turn causes the spring sheet in the buffer bladder to bend. When the spring sheet bends to its limit, it bends inward, and the resulting vibration disturbs the stability of the supersaturated sodium acetate solution in the buffer bladder, causing the solution to begin to crystallize around the spring sheet. Since it is a supersaturated solution, once the crystallization process begins, it triggers a chain reaction, and the crystals continue to grow until all the solution crystallizes. Crystallization is an exothermic process, so heat will be continuously released during the crystallization process, thereby buffering the external temperature difference.

[0026] Similarly, at high temperatures, the external heat is absorbed by the supersaturated sodium acetate solution in the buffer bladder, gradually breaking the crystallization state and performing energy storage, waiting for the next cycle. This can slow down the temperature difference changes on the outside of the LNG pipe, avoid high-intensity thermal shock, and prevent the generated thermal stress from exceeding the yield limit of the LNG pipe material, which could lead to damage to the metal components, thus improving its thermal shock resistance.

[0027] (5) The preparation method of the present invention is simple, the connection strength is high, and it is not easy to delaminate and separate. It can effectively improve the service life of foam glass, has market prospects, and is suitable for promotion and application. Attached Figure Description

[0028] Figure 1 This is a schematic diagram of the front structure of this application;

[0029] Figure 2 for Figure 1 Enlarged structural diagram of section A in the middle;

[0030] Figure 3 This is a schematic diagram of the exploded structure of the high-density insulation layer and the low-density insulation layer proposed in this application;

[0031] Figure 4 for Figure 3 Enlarged structural diagram of section B;

[0032] Figure 5 This is a schematic diagram of the assembly groove proposed in this application;

[0033] Figure 6 This is a schematic diagram showing the distribution of the glass connecting fibers proposed in this application;

[0034] Figure 7 This is a schematic diagram of the V-shaped support proposed in this application under compression.

[0035] Figure 8 This is a schematic diagram of the V-shaped support proposed in this application under low-temperature conditions;

[0036] Figure 9 This is a schematic diagram of the V-shaped bracket proposed in this application under high temperature conditions;

[0037] Figure 10 This is a schematic flowchart illustrating the method for preparing the thermal shock resistant foam glass structure for LNG pipelines according to this application.

[0038] Explanation of the labels in the diagram:

[0039] Outer protective layer 1, high-density insulation layer 2, high-density outer layer 21, high-density inner layer 22, low-density insulation layer 3, low-density outer layer 31, low-density inner layer 32, assembly groove 33, thermal shock resistant structure 4, V-shaped bracket 41, liquid reservoir 42, buffer bladder 43, spring sheet 44, glass connecting fiber 5. Detailed Implementation

[0040] The embodiments will be described clearly and completely with reference to the accompanying drawings. All other embodiments obtained by those skilled in the art based on the embodiments in this application without creative effort are within the scope of protection of this application.

[0041] Example 1:

[0042] This invention provides a thermal shock resistant foam glass structure for LNG pipelines. Please refer to [link / reference]. Figure 1-9 It includes a high-density insulation layer 2 and an outer protective layer 1 that are sequentially wrapped around the LNG pipeline from the inside out. The high-density insulation layer 2 includes a high-density outer layer 21 and a high-density inner layer 22. A low-density insulation layer 3 is bonded between the high-density outer layer 21 and the high-density inner layer 22. The low-density insulation layer 3 includes a low-density outer layer 31 and a low-density inner layer 32. A thermal shock resistant structure 4 is bonded between the low-density outer layer 31 and the low-density inner layer 32.

[0043] The thermal shock protection structure 4 includes V-shaped supports 41 evenly distributed at equal angles between the low-density outer layer 31 and the low-density inner layer 32. A liquid storage bladder 42 is fixed between the top ends of two adjacent V-shaped supports 41. A buffer bladder 43 is fixed inside the bottom V-shaped angle of the V-shaped supports 41. A spring sheet 44 is also fixed inside the bottom V-shaped angle of the V-shaped supports 41. The spring sheet 44 extends and seals inside the buffer bladder 43. The liquid storage bladder 42 is filled with a low-temperature crystallizing liquid, and the buffer bladder 43 is filled with a phase change heat storage material.

[0044] It should be noted that, in this embodiment, the liquid filled in the reservoir 42 is water, the phase change heat storage material filled in the buffer 43 is a supersaturated sodium acetate solution, and the elastic coefficient at the connection node between the reservoir 42 and the V-shaped support 41 is greater than the elastic coefficient of the rest of the reservoir 42.

[0045] Among them, both the high-density insulation layer 2 and the low-density insulation layer 3 are foam glass structures. The pore size of the foam pores in the high-density insulation layer 2 is larger than that in the low-density insulation layer 3, and the distribution density of the foam pores in the high-density insulation layer 2 is greater than that in the low-density insulation layer 3.

[0046] With its double-layer high-density insulation layer 2 and double-layer low-density insulation layer 3, compared to the traditional single-layer insulation structure, it can perform multiple interval heat exchanges and step-by-step heat exchanges when the external environment undergoes drastic temperature changes. This achieves the goal of generating a smaller temperature difference inside the LNG pipe when it is subjected to rapid heating and cooling, effectively mitigating impact thermal stress.

[0047] Please see Figure 1-2 and Figure 7 The outer protective layer 1 is made of polyisocyanurate foam, and a high-density polyisocyanurate rigid sheath is fitted on the outside of the outer protective layer 1. The V-shaped bracket 41 is an elastic plastic structure. When the V-shaped bracket 41 is not under force, the spring sheet 44 is bent.

[0048] The design of the outer protective layer 1 enhances the corrosion and aging resistance of the foam glass structure. Furthermore, the cooperation between the outer protective layer 1 and the elastic V-shaped support 41 allows the outer protective layer 1 and the V-shaped support 41 to absorb kinetic energy when an external impact occurs. This effectively protects the high-density insulation layer 2 and the low-density insulation layer 3 from collapse due to excessive impact, thereby improving their service life and insulation performance.

[0049] Among them, the low-density outer layer 31 and the low-density inner layer 32 are provided with assembly grooves 33 on opposite sides. The assembly grooves 33 match the outer contours of the V-shaped bracket 41, the liquid storage bladder 42, and the buffer bladder 43. Glass connecting fibers 5 are added during the preparation of the low-density insulation layer 3. The glass connecting fibers 5 are used to increase the bonding strength between the low-density insulation layer 3, the high-density insulation layer 2, and the thermal shock protection structure 4.

[0050] By using the glass connecting fiber 5, the bonding strength between the low-density insulation layer 3, the high-density insulation layer 2, and the thermal shock protection structure 4 is effectively enhanced when they are bonded together. This prevents delamination under severe temperature differences, effectively improves the structural strength, and increases the service life.

[0051] This invention utilizes a thermal shock protection structure 4 consisting of a V-shaped support 41, a liquid reservoir 42, a buffer 43, and a spring sheet 44, in conjunction with a high-density insulation layer 2 and a low-density insulation layer 3. In practical use, the high-density insulation layer 2 and the low-density insulation layer 3 perform conventional insulation. When extreme temperature changes occur, such as at low temperatures, the water in the liquid reservoir 42 freezes due to the low temperature, causing expansion and squeezing the end of the V-shaped support 41. At this time, the V-shaped support 41 is compressed and overcomes its own elastic deformation, which in turn causes the spring sheet 44 in the buffer 43 to bend. When the spring sheet 44 bends to its limit and bends inward, the resulting vibration disturbs the stability of the supersaturated sodium acetate solution in the buffer 43, causing the solution to begin crystallizing around the spring sheet 44. Since it is a supersaturated solution, once the crystallization process begins, it triggers a chain reaction, and the crystals continue to grow until all the solution crystallizes. Crystallization is an exothermic process, so heat is continuously released during the crystallization process, thus buffering the external temperature difference.

[0052] Similarly, when the temperature is high, the heat from the outside will be absorbed by the supersaturated sodium acetate solution in the buffer bladder 43, gradually breaking the crystallization state and performing energy storage, waiting for the next cycle. This can slow down the temperature difference change on the outside of the LNG pipe, avoid high-intensity thermal shock, and prevent the generated thermal stress from exceeding the yield limit of the LNG pipe material, which could lead to damage to the metal parts and improve its thermal shock resistance.

[0053] Example 2:

[0054] This invention provides a thermal shock resistant foam glass structure for LNG pipelines and its preparation method. Please refer to [link to relevant documentation]. Figure 1-10 Specifically, it includes the following steps:

[0055] S1. Clean the waste glass, dry it, and then ball mill the waste glass. Mix 40-60 parts waste glass powder, 10-15 parts carbon black, 5-10 parts aluminate, 5-10 parts expanded graphite, and 1-2 parts fluxing agent according to the mass ratio. After ball milling, drying, and sieving, the mixture is placed in a graphite crucible and melted. After melting, the mixture is water quenched. The water-quenched mixture is placed in a rotary drying oven to dry and then crushed to obtain basic glass powder.

[0056] S2. Take the basic glass powder, pass it through a 220-mesh sieve, and transfer it into a graphite crucible. Then add the foaming agent, foam stabilizer, and composite nucleating agent in sequence. Stir mechanically for 20 minutes to mix it evenly. Add it to a ball mill jar and ball mill for 20-40 minutes. Pass it through a 250-mesh standard sieve to obtain the batch material.

[0057] S3. Add industrial ethanol to the batch material, fill the batch material into the mold, spread it flat and compact it, with a thickness of 4cm-6cm, and finally transfer the mold into the foaming furnace to fire into foam glass.

[0058] S4. The prepared foam glass is divided into a high-density insulation layer 2 and a low-density insulation layer 3 according to the pore density. After assembling the thermal shock protection structure 4 in the low-density insulation layer 3, the high-density insulation layer 2 is glued to both sides of the low-density insulation layer 3 to prepare a thermal shock protection foam glass structure for LNG pipelines.

[0059] It should be noted that in this embodiment, if the finished product is a low-density insulation layer 3, then in step S3, glass connecting fibers 5 need to be added to the batch material. The finished low-density insulation layer 3 is prepared by wire cutting to divide the assembly groove 33 in the middle, and the low-density insulation layer 3 is separated into a low-density outer layer 31 and a low-density inner layer 32.

[0060] The preparation method of this invention is simple, with high bonding strength and is not easy to delaminate and separate. It can effectively improve the service life of foam glass, has market prospects, and is suitable for promotion and application.

[0061] The above description is only the best implementation method adopted in this application in combination with current practical needs, but the scope of protection of this application is not limited thereto.

Claims

1. A thermal shock resistant foam glass structure for LNG pipelines, comprising a high-density insulation layer (2) and an outer protective layer (1) sequentially wrapped around the LNG pipeline from the inside out, characterized in that, The high-density insulation layer (2) includes a high-density outer layer (21) and a high-density inner layer (22). A low-density insulation layer (3) is bonded between the high-density outer layer (21) and the high-density inner layer (22). The low-density insulation layer (3) includes a low-density outer layer (31) and a low-density inner layer (32). A thermal shock resistant structure (4) is bonded between the low-density outer layer (31) and the low-density inner layer (32). The thermal shock protection structure (4) includes V-shaped supports (41) evenly distributed at equal angles between the low-density outer layer (31) and the low-density inner layer (32). A liquid reservoir (42) is fixed between the top ends of two adjacent V-shaped supports (41). A buffer bladder (43) is fixed inside the bottom V-shaped angle of the V-shaped supports (41). A spring sheet (44) is also fixed inside the bottom V-shaped angle of the V-shaped supports (41). The spring sheet (44) extends and seals inside the buffer bladder (43). The liquid storage bladder (42) is filled with a low-temperature crystalline liquid, and the buffer bladder (43) is filled with a phase change heat storage material.

2. The thermal shock resistant foam glass structure for LNG pipelines according to claim 1, characterized in that, The liquid filling the reservoir (42) is water, and the phase change heat storage material filling the buffer bladder (43) is a supersaturated sodium acetate solution.

3. The thermal shock resistant foam glass structure for LNG pipelines according to claim 1, characterized in that, Both the high-density insulation layer (2) and the low-density insulation layer (3) are foam glass structures. The pore size of the foam pores in the high-density insulation layer (2) is larger than that in the low-density insulation layer (3), and the distribution density of the foam pores in the high-density insulation layer (2) is greater than that in the low-density insulation layer (3).

4. The thermal shock resistant foam glass structure for LNG pipelines according to claim 1, characterized in that, The outer protective layer (1) is polyisocyanurate foam, and a high-density polyisocyanurate rigid sheath is fitted on the outside of the outer protective layer (1).

5. The thermal shock resistant foam glass structure for LNG pipelines according to claim 1, characterized in that, The low-density outer layer (31) and the low-density inner layer (32) are each provided with an assembly groove (33) on opposite sides. The assembly groove (33) matches the outer contour of the V-shaped bracket (41), the liquid reservoir (42), and the buffer bladder (43).

6. The thermal shock resistant foam glass structure for LNG pipelines according to claim 1, characterized in that, The low-density insulation layer (3) is prepared with glass connecting fibers (5), which are used to increase the bonding strength between the low-density insulation layer (3), the high-density insulation layer (2), and the thermal shock protection structure (4).

7. The thermal shock resistant foam glass structure for LNG pipelines according to claim 1, characterized in that, The V-shaped bracket (41) is an elastic plastic structure. When the V-shaped bracket (41) is not under stress, the spring sheet (44) is bent.

8. A thermal shock resistant foam glass structure for LNG pipelines according to claim 1, characterized in that, The elastic coefficient at the connection point between the reservoir (42) and the V-shaped support (41) is greater than the elastic coefficient of the rest of the reservoir (42).

9. The method for preparing a thermal shock resistant foam glass structure for LNG pipelines according to claim 1, characterized in that, Specifically, the following steps are included: S1. Clean the waste glass, dry it, and then ball mill the waste glass. Mix 40-60 parts waste glass powder, 10-15 parts carbon black, 5-10 parts aluminate, 5-10 parts expanded graphite, and 1-2 parts fluxing agent according to the mass ratio. After ball milling, drying, and sieving, the mixture is placed in a graphite crucible and melted. After melting, the mixture is water quenched. The water-quenched mixture is placed in a rotary drying oven to dry and then crushed to obtain basic glass powder. S2. Take the basic glass powder, pass it through a 220-mesh sieve, and transfer it into a graphite crucible. Then add the foaming agent, foam stabilizer, and composite nucleating agent in sequence. Stir mechanically for 20 minutes to mix it evenly. Add it to a ball mill jar and ball mill for 20-40 minutes. Pass it through a 250-mesh standard sieve to obtain the batch material. S3. Add industrial ethanol to the batch material, fill the batch material into the mold, spread it flat and compact it. The thickness of the material is 4cm-6cm. Finally, move the mold into the foaming furnace and fire it into foam glass. S4. The prepared foam glass is divided into a high-density insulation layer (2) and a low-density insulation layer (3) according to the pore density. After assembling the thermal shock protection structure (4) in the low-density insulation layer (3), the high-density insulation layer (2) is glued to both sides of the low-density insulation layer (3) to prepare a thermal shock protection foam glass structure for LNG pipelines.

10. A method for preparing a thermal shock resistant foam glass structure for LNG pipelines according to claim 9, characterized in that, If the finished product is a low-density insulation layer (3), then in step S3, glass connecting fibers (5) need to be added to the batch material. The finished low-density insulation layer (3) is divided into a partition assembly groove (33) by wire cutting, and the low-density insulation layer (3) is separated into a low-density outer layer (31) and a low-density inner layer (32).

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