JP2754869B2 - Cold-resistant insulation spray material - Google Patents

Description

DETAILED DESCRIPTION OF THE INVENTION << Industrial Application Field >> The present invention relates to a heat-insulating spray material applied by spraying to a wall surface of a low-temperature structure such as an LNG low-temperature storage tank.

<< Conventional Technology >> When storing low temperature and flammable liquids such as LNG,
If LNG leaks out for any reason, it is necessary to apply heat insulation to suppress the generation of BOG (boil-off gas) and minimize the impact on the surroundings.

In general, when performing cold-resistant insulation treatment on the wall surface, ceiling surface, floor surface, etc. of a building structure, a heat insulation panel formed to a certain size in advance is attached to the relevant structure surface, or a formwork is used. A construction method of integrating a heat-insulated molded product with a corresponding structure surface has been implemented.

In addition, spraying of a special organic foaming agent is also performed in a very small part.

<< Problems to be solved by the invention >> However, in the former method using a heat insulating panel,
It could not be brought into close contact with the surface of the structure, and it was difficult to attach it to a complicated curved surface.

In the latter case, the construction is complicated and the construction period is long.

Further, although this kind of heat insulating material has resistance to cold and heat insulation, few materials have fire resistance or nonflammability. In addition, although some organic foaming agents for spraying are referred to as flame-retardant, they are not suitable as fire-resistant materials because they may explode when exposed to high temperatures.

Therefore, when fire resistance and non-combustibility as well as heat insulation are required, as in the above-described structures such as low-temperature storage tanks, it is necessary to perform fire resistance together with the cold insulation and heat insulation. Man-hours had to be increased.

The present invention solves the above problems, and provides a cold-insulated spraying material that can be formed in a close contact state with a structure surface with a simple man-hour, and that can provide fire-resistant and non-combustible properties as well as cold-insulated properties. aimed to.

<< Means for Solving the Problems >> In order to achieve the above object, the present invention is a cold-resistant and heat-insulating spray material that is applied by spraying on a surface of a structure, 30-50% by weight of cement
And 10-40% by weight of perlite and 20 ~ of vermiculite
It was a mixture consisting of 30% by weight and the balance thickener, and this mixture was kneaded with water.

Of these cements, the purpose is to solidify the spraying material. If the composition ratio is below the lower limit of 20% by weight, the strength will decrease, and if the composition ratio exceeds the upper limit of 50% by weight, the heat insulating property will be reduced. In the range of 20 to 50% by weight, more preferably 25 to 45% by weight, gives a desired result.

The pearlite in the mixture is a perlite and is mainly mixed as an aggregate for imparting cold insulation resistance. When the composition ratio is below the lower limit of 10% by weight, the heat insulation property is reduced, If the content exceeds the upper limit of 40% by weight, there is a drawback that spraying becomes difficult. Therefore, the range is 10 to 40% by weight, more preferably 20 to 35% by weight.

The vermiculite is a material having a high water retention property, and is mainly mixed as an aggregate for imparting fire resistance. When the composition ratio is lower than the lower limit of 20% by weight, the fire resistance is reduced, and the upper limit is also reduced. If the content exceeds 30% by weight, a disadvantage occurs in that the heat insulating property is reduced. Therefore, the content is in the range of 20 to 30% by weight, and more preferably 25 to 35% by weight.

More specifically, the thickener is made of fireclay or the like, and is added to increase the viscosity of the mixture, prevent material loss due to rebound during spraying, and increase the rigidity of the material. The content is 10 to 15% by weight, and this range can maintain the balance between the coating workability at the time of spraying and splash prevention.

The above mixture is mixed and dispersed in water, and the water is premixed at about 10 to 30% by weight to adjust to a spray material having a viscosity suitable for spraying.

This spraying material is sprayed on the heat-insulating surface of the structure via the coating gun.

FIG. 1 shows an example of the structure of an LNG low-temperature storage tank as an example. A cylindrical space constructed in the ground through a bottom plate 1 and a partition wall 2 is used as a pool.
A metal double tank 3 for low-temperature storage is constructed on top.

Then, the spraying material is applied to the inside of the partition wall 2 to form the heat insulating wall 2a.

More specifically, as shown partially enlarged, the partition wall 2
The mesh 5 is arranged on the wall surface of the partition wall 2 via the anchor 4 and sprayed on the surface to integrally form the heat insulating wall 2a having a required thickness reinforced by the mesh 5 on the inner surface of the partition wall 2.

<< Operation >> The obtained heat-insulating wall has the same thermal conductivity and specific heat as a conventional heat-insulating panel of the same thickness or a heat-insulating wall constructed by molding, and other physical properties are comparable.

Furthermore, it has fire resistance and nonflammability as well as cold insulation resistance.

<< Effect of the Invention >> Therefore, according to the present invention, the cold-resistant and heat-insulating construction is simple and the construction period is shortened. In addition, since it is applied to the surface of the structure by spraying, there is no restriction on the construction location and shape of the wall, ceiling, floor, and the like.

In addition, since the obtained heat insulating wall has cold resistance, fire resistance, and non-flammability, it is suitable for preventing secondary disasters such as fires such as leakage of flammable low-temperature storage structures such as LNG. Structure.

<< Embodiment >> Next, an embodiment of the present invention will be described. However, it is not limited only to the following embodiments.

(Example) Compounding ratio: Alumina cement 40 (Wt%) Perlite 30 〃 Vermiculite 20 〃 Thickening agent (fire clay) 10 〃 Total 100 (Wt%) and a small amount of thickener are added and kneaded with water After adjusting the viscosity to a suitable value for spraying or the like, this was applied to the wall surface by gun spraying as shown in FIG.

(Comparative Example) Mixing ratio without refractory material: Alumina cement 50 (Wt%) Perlite 40 {Thickener (Fireclay) 10} Total 100 (Wt%) and a small amount of thickener were added. After kneading with water and adjusting to a viscosity suitable for spraying, this was applied to the wall surface by gun spraying as shown in FIG.

Next, a part of the cold-resistant and heat-insulating wall obtained by the example and the comparative example was used as a specimen, and various physical properties were examined based on JIS standards and the like. As a result, the results shown in Table 1 below were obtained.

The conventional products listed for comparison are generally used heat insulating panels.

From the results shown in the above table, the cold-resistant heat-insulating wall made of the sprayed material obtained in the example has superior physical strength to the conventional heat-insulating panel. Naturally, in the case of the comparative example, the physical strength is increased by the amount of cement, but the thermal conductivity is large and the heat insulating property is low.

Next, in order to further compare the specific heat and the thermal conductivity of each of the specimens and a specimen made of ordinary concrete, an LN2 evaporation test was performed. In this test method, as shown in FIG. 2, a specimen S is placed on the bottom surface of a cold insulator 11 having a concave cross section held on the load cell 10, LN2 is poured on the upper part thereof, and the LN2 is evaporated on the load cell 10 by evaporation of LN2. The change in the applied load is measured. If the thickness is the same and the outside air temperature is the same, the higher the specific heat of the specimen S, the lower the evaporation rate.

Then, the thickness of each specimen is 50mm (only the insulation panel is 110m
As a result of measuring the evaporation rate at 15 ° C. in m), the concrete shown in FIG. 3 was obtained in which the largest was concrete, and the comparative example, the example, and the conventional heat insulating panel were in this order.

Next, a fire resistance test was performed to examine the fire resistance and nonflammability of the examples.

The fire resistance test was performed in accordance with JISA1304 (fire resistance test method for building structural parts).

FIG. 4 shows the state of the test, in which a sample was mounted on one side of a test container A made of ceramic fiber and refractory brick.

The sample was placed on the surface of reinforced concrete B with a thickness of 20 cm.
5 cm of a cold-resistant and heat-insulating spray layer C is formed, and a reinforcing bar is buried at the center of the thickness of the reinforced concrete B.

The sample was placed so that the cold-resistant and heat-insulating spray layer C was on the inside, and this was heated by the gas burner D.

The heating condition was set to 1100 ° C in 2 hours.
Temperature of the cold and heat-insulated spray layer C, reinforced concrete B
The inside rebar temperature and the backside temperature of the reinforced concrete B were measured.

FIG. 5 is a graph showing the measurement results. The maximum temperature at the rebar position is about 52 ° C., the average maximum temperature is 51.2 ° C., and the “temperature at the steel position is 550 ° C.” indicated in JISA1304.
The following conditions were fully satisfied.

The back surface temperature of the thermal spraying layer C is about 140 ° C at the maximum.
With this temperature rise, the decrease in the strength of the reinforced concrete B has almost no effect.

[Brief description of the drawings]

FIG. 1 is a cross-sectional explanatory view showing an example of the structure of an LNG low-temperature storage tank to which the present invention is applied, FIG. 2 is a cross-sectional explanatory view showing an LN2 evaporation test apparatus, FIG. 3 is a graph showing an evaporation test result, FIG. 4 is an explanatory diagram of the fire resistance test, and FIG. 5 is a graph showing the results of the fire resistance test. 2 ... Partition wall (structure side) 2a ... Cold-resistant and heat-insulated wall (spray material)

Claims (1)

(57) [Claims] 1. A cold-resistant, heat-insulating spray material applied by spraying on a surface of a structure, wherein the cold-resistant, heat-resistant spray material comprises 30 to 50% by weight of cement and 10 to 40% by weight of pearlite.
And a mixture comprising 20 to 30% by weight of vermiculite and the remaining thickener, and the mixture is kneaded with water.