JPS62137499A - Breakwater for reserving low temperature liquefied gas - Google Patents

Abstract

PURPOSE:To get a breakwater low in evaporation amount of liquefied gas and high in its durability by arranging heat insulating material made of concrete using an obsidian foaming substance as its aggregate, on the inner side face of a breakwater and on the ground surface inside the breakwater. CONSTITUTION:Heat insulating material 3 made of concrete using an obsidian foaming substance as its aggregate is arranged on the inner side face of a breakwater 2, for reserving low temperature liquefied gas and on the ground surface inside the breakwater. And since a material meeting the qualifications on initial evaporation amount less than 15.0kg/m<2>, 180sec, thermal conductivity less than 0.12Kcal/m.hr. deg.C and compressive strength of 25kgf/cm<2> or more is used for this heat insulating material, the evaporation amount of liquefied gas can be restrained to an extremely low level and the durability of the breakwater can be improved.

Description

DETAILED DESCRIPTION OF THE INVENTION [Field of Industrial Application] The present invention relates to a liquid barrier installed around a storage tank for low-temperature liquefied gas such as LNG or LPG.

[Prior art]

Ground-mounted tanks for low-temperature liquefied gas are required to have a dike with the same volume.

The purpose of the liquid barrier is to prevent liquid from flowing outside in the event that liquefied gas leaks inside the tank. In addition, the insulation inside the dike is designed to prevent liquefied gas from leaking in the event of a leak.
The purpose is to suppress the amount of initial evaporation due to heat input from the ground surface and dike surface.

This initial evaporation amount is determined by the thermal conductivity of the object that the liquefied gas comes into contact with,
It depends on conditions such as density, specific heat, and surface temperature.

Therefore, it was necessary to install heat insulating material on the inner surface of the dike and on the ground surface within the dike to suppress the initial amount of evaporation. At the same time, this insulation material had to meet the following conditions:

(D) It is nonflammable. 1■ Excellent heat insulation performance.

(High compressive strength. ■Low water absorption. ■Good weather resistance. ■Durable.

■Easy to maintain and manage.

Conventionally, the following two methods have been used as insulation materials and construction methods that satisfy these conditions.

In other words, a method of gluing foam glass (7777 product name Cerome) boards with adhesive mortar etc. on the leveled concrete poured on the inner surface of the dike and the surface of the soil inside the dike, b.
There was a method of pouring concrete using nacreous foam aggregate in units of formwork (3m square) reinforced with wire mesh and the like.

However, in method a, the maximum dimension of the foam glass pode is 45
The size of the unit board is small at 5mm x 606ffIn, and it takes a lot of effort to install it. ■With the above board dimensions, the length and surface area of the joints are large, and the insulation properties of these parts are poor, resulting in an increase in the amount of evaporated gas when leaks occur. ■
Foam glass pods have low strength, so they are resistant to impacts such as falling objects and walking during maintenance.

Poor wear resistance. ■ Surface protection materials are required to improve weather resistance, which increases costs and requires time and effort for maintenance. ■
In the method of fixing foam glass boards with anchor bolts planted in the underlying concrete, the foam glass boards warp due to the heat of the sun, causing damage to the insulation layer. There were drawbacks such as.

Furthermore, in method b, (1) the thermal conductivity is high, the amount of initial evaporation is also large, and the heat insulation performance is inferior to other methods.

■It has a high water absorption rate, and the insulation performance decreases significantly due to water absorption.

■In order to provide weather resistance and water resistance, it is necessary to apply an epoxy waterproofing material or to lay glass cloth for reinforcement, resulting in high costs. [Objective of the Invention] This invention was developed under the above circumstances. This was done in consideration of the

The purpose is to reduce the initial amount of evaporation of liquefied gas, and at the same time to increase the durability of the insulation material placed on the inner surface of the embankment. # To propose a liquid barrier for low-temperature liquefied gas storage tanks that has excellent impact resistance, abrasion resistance, and weather resistance.

[Structure of the invention]

This invention uses obsidian foam as an aggregate as a heat insulating material on the inside surface of the dike and the ground surface inside the dike in a dike for a low-temperature liquefied gas storage tank, and the thermal conductivity is 0.12 KcaM/m, hr under the following conditions.
, 'C or less Compressive strength 25kgf/c
It is characterized by satisfying J or higher.

In this invention, the initial evaporation amount is 400 mm
A 400m x 50mm sample was glued to the bottom of a box made of cold insulation material (urethane foam) with a 400+nm x 400mm bottom and an open top, and the required amount of liquid nitrogen was instantly poured into the box and allowed to evaporate for 180 seconds. The amount is 24±2
This is a value measured in an atmosphere of 55±5% RH.

The initial evaporation amount is preferably as low as possible, but at least 15
kg/rr? Below, it must be at 180 seconds. If the value exceeds this value, the desired evaporation suppressing effect cannot be obtained.

Thermal conductivity is 0.12 KcaQ/m, hr, 'C average temperature 24.5 ± 0.5 or less, and it has a function of suppressing initial evaporation due to heat input from the base layer without a heat insulating layer of about 50 mm thickness. manifest. By setting the compressive strength to 25 kgf/cJ or more, damage caused by external force during maintenance or walking force can be prevented.

The aggregate must be obsidian foam. For example, when perlite foam is used instead of obsidian foam, the initial evaporation amount and thermal conductivity are inferior, and it is difficult to obtain thermal properties comparable to obsidian. Even if the initial evaporation rate and thermal conductivity of the pearlite foam aggregate were made to be the same as that of the foam-based concrete of the present application (hereinafter referred to as obsidian concrete), the compressive strength, water absorption, and weather resistance would be lower. It is undesirable because it has poor hardness and durability, and requires time and effort in surface treatment and maintenance, resulting in high cost.

Furthermore, even if a heat insulating material is made using foam glass that satisfies the initial evaporation amount and thermal conductivity of the present application, it is not preferable because it has poor compressive strength and other strengths, is easily damaged, and has poor durability and workability.

〔Example〕 This will be explained below with reference to examples.

The figure shows the construction status of the dike. 1 is the soil on which a low-temperature liquefied gas tank (not shown) is installed, and 2 is the dike constructed around it. This dike 2
Obsidian concrete plate-shaped insulation material 3 (
1.5mXL3mX50mm (thickness)) are laid out side by side, and the joints are filled with joint material 4. In the drawings, numeral 5 indicates an anchor bolt installed in the base of the embankment 2, and numeral 6 indicates a hole filling material for the anchor bolt portion formed in the heat insulating plate.

Place leveled concrete 7 on the soil 1 inside the dike 2, place welding hardware 8 on top of it, and assemble the formwork to form a 3mX
A layer of heat insulating material 3 is formed by pouring obsidian concrete 1 in units of 6 m x 50 mm (thickness). Moreover, a joint material 4 is packed in the joints.

The composition of the obsidian concrete used as the heat insulating material 3 of this liquid barrier 2 was as shown in the table below.

Table 1 *The obsidian aggregate used in Table 1 had the physical properties shown in Table 2. As a reference example, the physical property values of a pearlite foam used as an aggregate in a conventional heat insulating material under the same measurement conditions are also listed.

The obsidian concrete of the example is made of a plate with a thickness of 50III+, and its initial steaming is 5I! The amount is 4.20kg/1
It was 80 seconds. Further, its physical properties were as shown in Table 3.

Table 3 shows comparative examples of pearlite concrete using conventional pearlite foam as aggregate and foam glass (CEROM).
The physical property values are also listed.

In addition to the compositions shown in Table 1, for example, the compositions shown in Table 4
1fd stone concrete can also be used as insulation material for the liquid dike in this application.
IT-suitable.

Table 4 The physical properties of this obsidian concrete were as follows.

Initial evaporation jIi 4.72kg/rr? at18
0 second thermal conductivity 0.117KcaQ/m, hr, °C
Compressive strength: 45 pupils f/cnf Obsidian concrete with an aggregate/cement ratio of 7-0 (vot) is also suitable for use as the insulating concrete for the dike of the present application.

[Action and effect of the invention]

This invention consists of the above configuration. The insulating concrete made of obsidian concrete placed on the inner surface and internal ground surface of this dike can keep the initial evaporation amount and thermal conductivity to low values, and has high compressive strength and other strengths and is difficult to damage. Compared to conventional heat insulating materials such as pearlite concrete and foam glass, it has superior thermal properties and strength, and at the same time has sufficient water resistance and weather resistance.

The ground surface of this dike is covered with obsidian concrete (6m x
Since it can be constructed without a joint span dimension of 3 m), the ratio of the joint length and joint area is low, preventing an increase in the amount of evaporation due to the joint part, and reducing construction costs. In addition, it has excellent water resistance and weather resistance, so there is no need to apply a surface protection material.

As mentioned above, the insulating concrete laid inside this dike has excellent thermal properties as a heat insulating material, and at the same time has sufficient strength and durability. Furthermore, the construction cost of the insulation material is low, and the cost required for maintenance and management is also low.

[Brief explanation of drawings]

The drawing is a partially sectional perspective view of the construction state of the dike. 1...Soil, 2...Dike, 3...
Insulation material, 4... Base material, sealing material, 5...
Anchor bolt, 6... Anchor bolt burial material,
7. Leveling concrete h, 8. Welding metal training. Procedural Amendment 11 February 26, 1961 Patent Application No. 277519 2, Title of invention: Liquid barrier for low-temperature liquefied gas storage tank 3, Relationship with the person making the amendment Patent applicant address (137 ) Iπ Island Construction Co., Ltd. NICHIAS Co., Ltd. Name, Agent, Date of amendment order Spontaneous amendment details, Name of invention Liquid barrier dike 2 for low temperature liquefied gas storage tank, Claims 0) Low temperature liquefied gas storage tank A liquid barrier for a low-temperature liquefied gas storage tank, characterized in that a concrete layer that uses obsidian foam as aggregate and satisfies the following conditions as a heat insulating material is arranged on the inner surface of the liquid barrier and the ground surface within the bank as a heat insulating material. . Heat conduction 'J O, 12KcaQ/m,
hr, 'c or less Compressive strength 25kgf/
3. Detailed Description of the Invention [Field of Industrial Application] This invention relates to a liquid barrier installed around a storage tank for low-temperature liquefied gas such as LNG or LPG. [Prior Art] Ground-mounted tanks for low-temperature liquefied gas are required to have a dike with the same volume. The purpose of the liquid barrier is to prevent liquid from flowing outside in the event that liquefied gas leaks inside the tank. In addition, the insulation inside the dike is designed to prevent liquefied gas from leaking in the event of a leak.
The purpose is to suppress the initial amount of evaporation due to heat input from the ground surface and the surface of the dike.4 This initial amount of evaporation depends on conditions such as the thermal conductivity, density, specific heat, and surface temperature of the object with which the liquefied gas comes into contact. Depends on it. Therefore, it was necessary to install heat insulating material on the inner surface of the dike and on the ground surface within the dike to suppress the initial amount of evaporation. At the same time, this insulation material had to meet the following conditions: ■It is nonflammable. ■Excellent insulation performance. ■High compressive strength. ■Low water absorption ■Good weather resistance. ■Durable. ■Easy to maintain and manage. Conventionally, the following two methods have been used as insulation materials and construction methods that satisfy these conditions. In other words, a foam glass (trade name: CEROHM) board was glued and laid with adhesive mortar on the leveled concrete surface cast on the inner surface of the dike and the soil surface within the dike, 1) the tongue method, and b pearlite foam as bones. There was a method of pouring concrete as a material into formwork (3m square) with reinforcements such as wire mesh. However, in method a, the maximum dimension of the foam glass pode is 45
The size of the unit board is small at 5 mm x 606 mm, and it takes a lot of effort to install it. ■With the above board dimensions, the length and surface area of the base 11 are too large, and the Wr heat resistance of this part is poor, so the amount of evaporative gas when leaking increases. ■ Foam glass pods have low strength, so they have poor impact resistance and abrasion resistance against falling objects during maintenance, walking, etc. (Surface protection materials are required to increase weather resistance, which increases costs and requires time and effort to maintain.) ■With the method of fixing foam glass boards with anchor bolts planted in the underlying concrete, the foam glass boards are exposed to the heat of the sun. There were disadvantages such as warping and damage to the insulation layer.In addition, method b has a large thermal conductivity and a large amount of initial evaporation, making the insulation performance inferior to other methods.Water absorption rate However, KS <, the insulation performance decreases significantly due to water absorption.■ Disadvantages include high cost as it is necessary to apply epoxy waterproofing material to provide weather resistance and water resistance, and to reinforce it by laying glass cloth. [Purpose of the Invention] This invention was made in view of the above circumstances.The purpose is to reduce the initial evaporation amount of liquefied gas, and at the same time improve the impact resistance and abrasion resistance of the heat insulating material placed on the inner surface of the embankment. The purpose of the present invention is to propose a dike for a low-temperature liquefied gas storage tank that has excellent weather resistance. Thermal conductivity is 0.12KcaQ/m, hr using obsidian foam as the material and the following conditions:
, 'c or less, and compressive strength of 25 kgf/- or more. In this invention, the initial evaporation amount is 400 mm
A sample of 400nm x 50nvn was made of cold insulation material (urethane foam) with a bottom surface of 400mm x 400m.
Attach it to the bottom of a box with two open sides, and instantly pour the required amount of liquid nitrogen into the box to reduce the amount of evaporation by 2 for 180 seconds.
This is a value measured in an atmosphere of 4±2°C and 755±5% RH. The initial evaporation value is preferably as low as possible, but at least 15k.
g/m, 180 sec, or less. If the value exceeds this value, the desired evaporation suppressing effect cannot be obtained. Thermal conductivity is 0.12 KcaQ/m, hr, 'C average temperature 24.5 ± 0.5 or less, and it has a function of suppressing initial evaporation due to heat input from the base layer without a heat insulating layer of about 50 nyn thickness. manifest. By setting the compressive strength to 25 kgf/cJ or more, damage caused by external force during maintenance or walking force can be prevented. The aggregate must be obsidian foam. For example, when perlite foam is used instead of obsidian foam, the initial evaporation amount and thermal conductivity are inferior, and it is difficult to obtain thermal properties comparable to obsidian. Even if the softness of the pearlite foam aggregate is increased and the initial evaporation thermal conductivity is made to be the same as that of the foam-based concrete of the present application (hereinafter referred to as obsidian concrete), the compressive strength, water absorption, and weather resistance will be lower. The quality and durability are poor, and surface treatment and maintenance are time-consuming and the varnish is 1 to 1 high, which is not preferable. Furthermore, even if a heat insulating material is made using foam glass that satisfies the initial evaporation amount and thermal conductivity of the present application, it is not preferable because it has poor compressive strength and other strengths, is easily damaged, and has poor durability and workability. [Example] Examples will be described below. The figure shows the construction status of the dike. 1 is the soil on which a low-temperature liquefied gas tank (not shown) is installed, and 2 is the dike constructed around it. This dike 2
Obsidian concrete plate-shaped insulation material 3 (
1.5n+X1.3mX50mm (thickness)) are laid out side by side, and the joints are filled with joint material 4. In addition, in the drawing, 5 is an anchor bolt installed in the base of embankment 2,
6 is a hole filling material for an anchor bolt portion formed on a heat insulating plate. Leveled concrete 7 is placed on the soil 1 inside the dike 2, welding hardware 8 is placed on top of it, and the formwork is set up to a height of 3 m.
A layer of heat insulating material 3 is formed by pouring obsidian concrete with a size of 6 m x 50 mm (thickness). Moreover, a joint material 4 is packed in the joints. The composition of the obsidian concrete used as the heat insulating material 3 of this liquid barrier 2 was as shown in the table below. Table 1 *The obsidian aggregate used in Table 1 had the physical properties shown in Table 2. As a reference example, the physical property values of pearlite foam used as bone phase in a conventional heat insulating material under the same 71+q constant conditions are f.
) Write P. The obsidian concrete of the example was made into a plate with a thickness of 50 mm, and its initial evaporation amount was 4.20 kg/rn' 180
It was seconds. Further, its physical properties were as shown in Table 3. Table 3 shows comparative examples of pearlite concrete using conventional pearlite foam as aggregate and foam glass (CEROM).
The physical property values are also listed. In addition to the compositions shown in Table 3 and Table 1, for example, obsidian concrete having the composition shown in Table 4 is also suitable as a heat insulating material for the dike of the present application. Table 4 The physical properties of this obsidian concrete were as follows. Initial evaporation amount 4.72kg/rd at 180 seconds Thermal conductivity 0.117Kcal/m, hr, 'C
Compressive strength: 45 kgf/cJ. Obsidian concrete with an aggregate/cement ratio of 7.0 (Vol) is also suitable for use as the insulating concrete for the dike of the present application. [Operation and Effects of the Invention] This invention consists of the above configuration. The insulating concrete made of obsidian concrete placed on the inner surface and internal ground surface of this dike can keep the initial evaporation amount and thermal conductivity to low values, and has high compressive strength and other strengths and is difficult to damage. Compared to conventional heat insulating materials such as pearlite concrete and foam glass, it has superior thermal properties and strength, and at the same time has sufficient water resistance and weather resistance. The ground surface of this dike is covered with stone concrete (6m x
Since it can be constructed without a joint span dimension of 3 m), the ratio of joint length and joint area is low, preventing an increase in the amount of evaporation due to the joint, and reducing construction costs. Furthermore, since it has excellent water resistance and weather resistance, there is no need to apply a surface protection material. As described in Section 2 below, the insulating concrete 1 laid inside this dike has excellent thermal properties as a heat insulating material, and at the same time has sufficient strength and durability. In addition, the construction cost of the insulation material is low, and the cost required for maintenance pipe heels is also low. 4. Simplified explanation of the drawings The drawings are perspective views showing a partially sectional view of the construction state of the dike. 1...Soil, 2...Dike, 3...
・Insulation material, 4. Joint material, sealing material, 5. Anchor bolt, 6. Anchor bolt hole filling material, 7.
...Leveled concrete, 8...Welded wire mesh.

Claims (1)

[Claims] (1) A low-temperature levee for a low-temperature liquefied gas storage tank, characterized in that a concrete layer is placed on the inner surface of the levee and on the ground surface inside the levee as a heat insulator, using obsidian foam as aggregate and satisfying the following conditions. Liquid dike for liquefied gas storage tank. Initial evaporation amount (as liquid nitrogen evaporation amount) 15.0kg/m
^2 or less, at 180 seconds thermal conductivity 0.12 Kcal/m. hr. ℃
Compressive strength below 25kgf/cm^2 or more