JP4384396B2 - Cold resistance reducing material for low-temperature liquid tank, its construction method, and lining material - Google Patents

Description

[0001]
BACKGROUND OF THE INVENTION
The present invention relates to a thermal resistance reducing material used in a low-temperature liquid tank for storing a low-temperature liquid such as liquefied natural gas or liquefied petroleum gas, a construction method thereof, and the like.
[0002]
[Prior art]
FIG. 7 is a cross-sectional view illustrating the basic structure of a cryogenic liquid tank 50 that stores cryogenic liquids (gas and liquid) 80 such as liquefied natural gas and liquefied petroleum gas. In general, the cryogenic liquid tank 50 includes an inner shell 60 that holds the cryogenic liquid 80 and an outer shell 70 that serves as a cold insulator support portion. The low-temperature liquid tank 50 protects the outer shell 70 and the prestressed concrete (PC) casing 76 (by cold heat) in case the liquefied natural gas 80 is leaked from the inner shell 60 damaged during a disaster or the like. For the purpose of mitigating the influence, a thermal resistance mitigating material 90 is provided. In addition, as invention regarding a low-temperature liquid tank provided with a thermal-resistance resistance relaxation material, there exist a thing as described in following patent document 1, patent document 2, etc.
[0003]
Generally, such a thermal resistance reducing material 90 is made of a heat insulating layer 91 made of hard urethane foam or pearlite concrete, and a glass fiber reinforced urethane resin obtained by integrating a glass cloth and a urethane resin on the heat insulating layer 91. And a surface layer 96 having excellent properties.
According to such a surface layer 96, even if the low temperature liquid 80 leaks from the inner shell 60, it is possible to prevent the heat insulating layer 91 and the outer shell 70 from contacting the low temperature liquid 80 directly. As a result, the occurrence of a serious defect such as a crack in the heat insulation layer 91 is avoided.
[0004]
Conventionally, such a surface layer 96 is formed as follows. A urethane resin-based adhesive is applied to the surface of the pearlite concrete heat insulating layer 91 placed on the inside of the outer shell (bottom liner plate) 70, and then a glass cloth is attached to this surface. Further, ironing is performed from above, and a glass cloth is impregnated with a urethane resin adhesive. After curing the urethane resin adhesive over night, apply the urethane resin adhesive on it, paste another glass cloth, and impregnate the glass cloth with urethane resin adhesive. And let it cure overnight. Thus, a surface layer 96 made of glass fiber reinforced urethane resin in which two glass cloth layers are integrated on the heat insulating layer is formed.
[0005]
[Patent Document 1]
JP-A-10-101191 [Patent Document 2]
JP-A-6-34098 [0006]
[Problems to be solved by the invention]
However, when constructing such a cold resistance mitigating material, generally used low-temperature-resistant urethane resin adhesives have foaming properties. If fine bubbles generated when the glass cloth is impregnated with such an adhesive remain, fine holes (pinballs) penetrating in the vertical direction are formed in the surface layer 91. There is a concern that such a pinball cannot maintain the liquid-stopping property of the surface layer.
[0007]
In order to avoid such a situation, the work of impregnating the glass resin with the urethane resin-based adhesive in order to prevent fine bubbles from remaining requires a great deal of attention, which places a lot of burden on the operator.
The present invention has been made in view of such problems, and provides a thermal resistance relaxation material for a low-temperature liquid tank that can be efficiently formed in a short period of time because it is easy to construct and has no performance defect, and a construction method thereof. The purpose is to do.
[0008]
[Means for Solving the Problems]
In order to achieve the above object, a first invention is a cold resistance relaxation material for a cryogenic liquid tank for protecting the outer shell of a cryogenic liquid tank having a double shell structure of an inner shell and an outer shell from cold heat. A heat insulating layer laminated on the outer shell bottom liner plate, and a surface layer formed on the heat insulating layer, the surface layer impregnating a cloth made of inorganic fiber with a low temperature resistant resin adhesive. The first inorganic fiber reinforced low temperature resistant resin layer, the metal foil layer laminated on the first inorganic fiber reinforced low temperature resistant resin layer, and the low temperature resistant resin laminated on the metal foil layer. Second inorganic fiber reinforced low temperature resistant resin layer impregnated with an adhesive, and the density of the inorganic fiber cloth is higher in the inorganic fiber cloth of the second inorganic fiber reinforced low temperature resistant resin layer The density of the inorganic fiber cloth of the first inorganic fiber reinforced low temperature resistant resin layer is lower The thickness of the metal foil layer is characterized by a 15～80Myuemu.
[0009]
According to such a configuration, even if pinholes are formed in the inorganic fiber reinforced low temperature resistant resin layer, the liquid stopping property of the surface layer is ensured by the metal foil layer. As a result, even if the inner shell breaks due to a disaster or the like and the cryogenic liquid leaks, it is possible to prevent the thermal insulation layer and the outer shell from coming into direct contact with the cryogenic liquid, resulting in a crack inside the thermal insulation layer. The occurrence of serious defects such as is avoided.
Here, “low temperature resistant resin adhesive” includes natural rubber, synthetic rubber, epoxy resin, and urethane resin, but urethane resin adhesive is used from the viewpoint of versatility. It is preferable.
[0010]
A second invention is a method for constructing a cold resistance reducing material for a cryogenic liquid tank for protecting the outer shell of a cryogenic liquid tank having a double shell structure of an inner shell and an outer shell from cold heat, and comprising an outer shell bottom liner The first step of placing a heat insulating layer on the plate in situ, the second step of applying a low temperature resistant resin adhesive to the surface of the heat insulating layer laminated on the liner plate, and the applied low temperature resistant resin A third step of applying a lining material in which a metal foil is sandwiched between inorganic fiber cloths on the adhesive and a fourth step of applying a low temperature resistant resin adhesive to the surface of the attached lining material. The density of the inorganic fiber cloth of the lining material is higher in the inorganic fiber cloth on the surface side, the density of the inorganic fiber cloth on the heat insulation layer side is lower, and the thickness of the metal foil layer is 15 to 80 μm. It is characterized by that.
[0011]
According to such a construction method, it is possible to manufacture a lining material having a liquid stopping property in advance. And when forming the inorganic fiber reinforced low temperature resistant resin layer in the field construction, construction work can be done without worrying about the generation of pinholes, and it is possible to reliably construct the surface layer with secured liquid stopping property . Moreover, the working time is greatly reduced.
[0012]
According to a third aspect of the present invention, in order to protect the outer shell of the cryogenic liquid tank having a double shell structure of the inner shell and the outer shell from cold heat, the surface is stuck on the heat insulating layer laminated on the outer shell bottom liner plate. A lining material for forming a layer, the lining material is configured by sandwiching a metal foil between inorganic fiber cloths, the density of the inorganic fiber cloth is higher in the inorganic fiber cloth on the side of the anti-heat insulating layer, The inorganic fiber cloth on the heat insulating layer side has a lower density, and the thickness of the metal foil layer is 15 to 80 μm .
[0013]
According to such a configuration, the inorganic fiber reinforced low temperature resistant resin layer can be easily formed on both sides of the metal foil by impregnating the inorganic fiber cloth with the low temperature resistant resin adhesive.
Also, such lining materials can be easily manufactured with high quality at the factory.
[0014]
Here, it is preferable that the metal foil has a thickness of 15 μm or more, which generally eliminates pinholes, in order to ensure liquid-stopping properties. Such a metal foil may be made of aluminum, iron, stainless steel, zinc, or an alloy thereof. In particular, it is preferable to use aluminum from the viewpoint of versatility.
The thickness of the metal foil is preferably 15 to 80 μm. If it is 15 μm or less, the strength is weak and the rate of occurrence of pinholes is high, and there is a risk that the liquid-stopping property cannot be ensured by breaking during construction. On the other hand, if it exceeds 80 μm, the flexibility is lost and the construction becomes difficult.
[0015]
It is preferable that the inorganic fiber cloth has a density of 15/25 mm to 50/25 mm and a thickness of 0.10 mm to 0.3 mm. When the density is 10 pieces / 25 mm or less, the strength of the formed inorganic fiber reinforced low temperature resistant resin layer is insufficient. If the thickness exceeds 0.3 mm, the rigidity of the cloth increases and becomes harder, so air voids and wrinkles are more likely to occur.
The density of the inorganic fiber cloth used for the lining material may be high on the upper surface, and lower on the lower surface side in contact with the concrete forming the heat insulating layer. According to such a configuration, even when an operator rides on the lining material at the time of construction, the metal foil is protected by the inorganic fiber cloth fixed on the upper surface, so it is avoided that it is torn unnecessarily. The On the other hand, the low temperature resistant resin adhesive can easily enter the stitches of the cloth on the lower surface. As a result, the adhesiveness with the heat insulating layer is improved.
As a material for such an inorganic fiber cloth, a material composed of alumina fiber, ceramic fiber, glass fiber alone, or a material composed of these composite fibers may be used. In particular, it is preferable to use a glass fiber that has low temperature resistance and good compatibility with the low temperature resistant resin adhesive.
[0016]
In order to fix the metal foil and the inorganic fiber cloth, urethane, epoxy, acrylic resin, synthetic rubber, or natural rubber used for lamination may be used. In particular, an adhesive having low temperature resistance may be used. Moreover, it is preferable to use an adhesive having flexibility even after curing. In this case, since the sheet material can maintain flexibility, the construction becomes easy.
[0017]
DETAILED DESCRIPTION OF THE INVENTION
Embodiments of the present invention will be described with reference to the drawings.
FIG. 1 is an explanatory view showing the structure of the surface layer 9 in the cryogenic resistance relaxation material for a cryogenic liquid tank.
The surface layer 9 is formed using a lining material 10. That is, the lining material 10 is configured by sandwiching an aluminum foil 13 which is a metal foil between glass fiber cloths 11 and 11 which are inorganic fiber cloths from both sides. The glass fiber cloth 11, 11 is impregnated with urethane resin adhesives 15, 15 which are low temperature resistant resin adhesives, thereby forming glass cloth reinforced urethane resin layers 18, 18. In this manner, the surface layer 9 including three layers of the glass cloth reinforced urethane resin layer 18, the metal foil 13, and the glass cloth reinforced urethane resin layer 18 is formed. In addition, it is not always necessary to use a lining material for forming the surface layer, and it is only necessary to finally include three layers of the glass cloth reinforced urethane resin layer 18, the metal foil 13, and the glass cloth reinforced urethane resin layer 18.
[0018]
FIG. 2 is an explanatory view showing a construction method of the cold resistance reducing material for a cryogenic liquid tank according to the present invention.
First, as a first step, pearlite concrete 20 serving as a heat insulating layer is placed on-site on the bottom liner plate 40 of the outer shell 70 of the cryogenic liquid tank.
Next, as a second step, a urethane resin adhesive 16 is applied on the pearlite concrete 20.
As a third step, the lining material 10 shown in FIG. 1 constituting the surface layer is stuck on the applied urethane resin adhesive 16.
And as a 4th process, the urethane resin adhesive 17 is apply | coated to the surface of the affixed lining material 10. FIG.
Then, on the bottom liner plate 40, the cold resistance reducing material 30 for the low temperature liquid tank provided with the pearlite concrete (heat insulating layer) 20 and the surface layer 9 is formed.
[0019]
FIG. 3 is a table comparing the construction time of the surface layer between the construction method according to the present invention and the conventional construction method. In any construction method, there are two times that the adhesive is cured overnight. However, in addition to this, in the conventional construction method, it takes a lot of work time to squeeze the glass fiber cloth in the process (2) (5).
[0020]
On the other hand, in the construction method according to the present invention, some work time is required in the step (2) of attaching the lining sheet material 10. However, as a whole, it is suppressed to less than half of the conventional construction method (conventional construction method 22 minutes / m ² / person: construction method 9 minutes / m ² / person according to the present invention), and a significant reduction in work time can be realized.
[0021]
Further, since the lining sheet material 10 constituting the surface layer is laminated with the aluminum foil 13 sandwiched therebetween, the lining sheet material 10 is more resistant to low temperature liquid leakage from the inner shell than the conventional surface layer simply laminated with glass cloth. Increases liquid stopping properties.
[0022]
【Example】
Next, the present invention will be described in more detail based on examples (including comparative examples).
FIG. 4 is a schematic view showing a test apparatus 42 used in this embodiment. In this test apparatus 42, a space 43 surrounded by concrete 46 and an external heat insulating material 47 is formed on a gantry 45. Then, a liner plate 40 is laid on the concrete 46, and a cold resistance reducing material for a cryogenic liquid tank as a test body is attached on the liner plate 40. A steel pipe 48 is piped in the space 43 so that LN ₂ (liquid nitrogen) is dispersed.
[0023]
The test method is as follows.
1) After attaching a test body (cooling resistance relaxation material for a cryogenic liquid tank) to the test apparatus 42, LN ₂ is sprayed from the steel pipe 48 on the top of the test body.
2) LN ₂ is supplied and the state where LN ₂ is stored on the upper surface of the test body is maintained.
3) Hold that state for at least 18 hours from the start of the test.
4) After completion of the above procedure, the specimen is naturally heated to near room temperature.
5) Observe the surface state of the specimen visually.
6) During the test, the temperature (including the ambient temperature) is measured with a thermocouple installed at each location. The temperature measurement positions are 8 planes shown in FIG. 5 (I), 4 height directions shown in FIG. 5 (II), and 8 × 4 = 32 places in total.
[0024]
First, as a comparative example, the test results of a test body using a conventional surface layer (cooling resistance reducing material for low-temperature liquid tank) are as follows.
(1) About the temperature measurement result As an example of the temperature measurement result, the temperature change curve of the cooled specimen at each measurement height (A, B, C, D) at the measurement point (7) is shown in FIG. According to this, there was no rapid temperature change for each point of the concrete body temperature measurement point from the start of the test until about 19 hours later. The other measurement points ((1) to (6) and (8)) showed the same tendency.
(2) As to the appearance of the test specimen, the appearance of the test specimen after cooling was confirmed by visual observation. As a result, no abnormal parts such as cracks and peeling between the surface layer and the heat insulating layer (pearlite concrete) were observed for the surface layer. . No harmful cracks or the like were observed for the heat insulating layer (perlite concrete). For the liner plate 40, no abnormal site was observed.
[0025]
Next, the test result of the test body (cooling resistance reducing material for low-temperature liquid tank) using the surface layer according to the present invention as an example is as follows.
(1) About the temperature measurement result As an example of the temperature measurement result, the temperature change curve of the cooled specimen at each measurement height (A, B, C, D) at the measurement point (7) is shown in FIG. According to this, the temperature change curve of the test body using the surface layer according to the present invention showed almost the same tendency as the comparative example shown in FIG. The other measurement points ((1) to (6) and (8)) showed the same tendency as in the comparative example.
(2) As to the appearance of the test specimen, the appearance of the test specimen after cooling was confirmed by visual observation. As a result, no abnormal parts such as cracks and peeling between the surface layer and the heat insulating layer (pearlite concrete) were observed for the surface layer. . No harmful cracks or the like were observed for the heat insulating layer (perlite concrete). For the liner plate 40, no abnormal site was observed.
[0026]
In this example, a rapid temperature change of the concrete 46 was not observed. Also, the appearance after cooling was good with no observed abnormal parts such as cracks and peeling. Therefore, even if it compares with a comparative example, it is thought that the cold-heat resistance relaxation material for low-temperature liquid tanks concerning this invention has sufficient cold-heat resistance and a cold-heat relaxation function.
[0027]
【The invention's effect】
The present invention has the following effects.
First, since the surface layer is laminated with the metal foil sandwiched, the liquid-stopping property at the time of low-temperature liquid leakage from the inner shell is higher than the conventional surface layer simply laminated with inorganic fiber cloth. .
Secondly, by using a lining material that has already been processed in order to form the surface layer, the working time at the site can be shortened. On the other hand, it has sufficient cooling resistance and cooling relaxation function that do not replace the conventional cooling resistance relaxation material for low-temperature liquid tanks.
[Brief description of the drawings]
FIG. 1 is an explanatory diagram showing the structure of a surface layer.
FIG. 2 is an explanatory view showing a construction method of a thermal resistance relaxation material for a cryogenic liquid tank.
FIG. 3 is a table showing the construction time of the surface layer.
FIG. 4 is a schematic view showing a test apparatus used in Examples.
FIG. 5 is an explanatory diagram showing a temperature measurement position.
FIG. 6 is a curve graph showing a temperature change of a conventional example.
FIG. 7 is a curve graph showing a temperature change in the example.
FIG. 8 is an explanatory sectional view showing a basic structure of a cryogenic liquid tank.
[Explanation of symbols]
9 Surface Layer 10 Lining Sheet Material 16 Urethane Resin Adhesive 17 Urethane Resin Adhesive 20 Perlite Concrete 30 Cooling Resistance Relief Material for Low Temperature Liquid Tank 40 Bottom Liner Plate

Claims (3)

A cold resistance relaxation material for a cryogenic liquid tank for protecting the outer shell of a cryogenic liquid tank consisting of a double shell structure of an inner shell and an outer shell from cold,
A heat insulating layer laminated on the outer shell bottom liner plate, and a surface layer formed on the heat insulating layer;
The surface layer includes a first inorganic fiber reinforced low temperature resistant resin layer obtained by impregnating an inorganic fiber cloth with a low temperature resistant resin adhesive, and a metal laminated on the first inorganic fiber reinforced low temperature resistant resin layer. A foil layer and a second inorganic fiber reinforced low temperature resin layer laminated on a metal foil layer and impregnated with a low temperature resin adhesive into an inorganic fiber cloth;
The density of the inorganic fiber cloth is higher in the inorganic fiber cloth of the second inorganic fiber reinforced low temperature resistant resin layer, and the density of the inorganic fiber cloth of the first inorganic fiber reinforced low temperature resistant resin layer is lower, The thickness of a metal foil layer is 15-80 micrometers, The cold / heat resistance relaxation material for low-temperature liquid tanks characterized by the above-mentioned. A method of constructing a cold resistance relaxation material for a cryogenic liquid tank for protecting the outer shell of a cryogenic liquid tank consisting of a double shell structure of an inner shell and an outer shell from cold heat,
A first step of placing a heat insulation layer in situ on the outer shell bottom liner plate;
A second step of applying a low temperature resistant resin adhesive on the surface of the heat insulating layer laminated on the liner plate;
A third step of attaching a lining material in which a metal foil is sandwiched between inorganic fiber cloths on the applied low-temperature resistant resin adhesive,
It has a fourth step of applying a low temperature resistant resin adhesive on the surface of the affixed lining material,
The density of the inorganic fiber cloth of the lining material is higher in the inorganic fiber cloth on the surface side, the density of the inorganic fiber cloth on the heat insulation layer side is lower, and the thickness of the metal foil layer is 15 to 80 μm The construction method of the cold resistance relaxation material for low-temperature liquid tanks characterized by this. In order to protect the outer shell of the cryogenic liquid tank consisting of a double shell structure of inner shell and outer shell from cold heat, the lining material is applied to the heat insulating layer laminated on the outer shell bottom liner plate to form the surface layer. Because
The lining material is composed of a metal foil sandwiched between inorganic fiber cloths,
The density of the inorganic fiber cloth is higher in the inorganic fiber cloth on the side of the heat insulation layer, the density of the inorganic fiber cloth on the side of the heat insulation layer is lower, and the thickness of the metal foil layer is 15 to 80 μm. Characteristic lining material.

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