JPS58214098A - Freezing preventing device of foundation for low-temperature liquid tank - Google Patents

Abstract

PURPOSE:To compensate for fluctuation in heat due to outside conditions by burying a regenerative pipe where a regenerative material is enclosed and heat pipe in the fundation concrete to store in the regenerative material a part of heat transported from a heating source by the heat pipe. CONSTITUTION:When a heat pipe 13 transports heat of hot water in a hot-water tank 15 to the foundation concrete 12, the heat transported by the heat pipe 13 is transmitted to the foundation concrete 12 and a regenerative pipe 14, so that a part of heat from the heat pipe 13 is stored in a regenerative material as latent heat. Therefore, even if the temperature of the concrete 12 is changed by outside conditions, the heat stored in the regnerative material 14 can compensate for it.

Description

[Detailed description of the invention] This invention is applicable to liquefied natural gas (LNG) and liquefied petroleum scum (LNG).
4515 with a tank for low-temperature liquid such as PG)
This is a dispute regarding a device to prevent concrete from freezing.

Among tanks that store low-temperature liquids such as LNG and LPG,
A large industrial tank 1 is usually constructed by pouring insulating concrete 3 such as perlite concrete on a foundation concrete 2 and installing it at F of the insulating concrete 3, but the insulating effect of the insulating concrete 3 is not necessarily sufficient. Therefore, the foundation concrete 2 may be cooled by the low temperature liquid in the tank 1, and as a result, the foundation concrete 2 may freeze. If such a situation occurs, the strength of the foundation concrete 2 may decrease or cracks may appear in the foundation concrete 2, and as a result, there is a danger that the tank 1 itself may sink unevenly. Second
As shown in the figure, an electric heater 5 inserted into a protective pipe 4 is buried in the M foundation concrete 1-2, and by energizing the electric heater 5 and generating heat, the temperature of the foundation concrete 2 is reduced to approximately 5. It is kept at around ℃ to prevent it from freezing.

However, since the electric heater 5 has weak mechanical strength, it is easily broken, and as a result, maintenance and inspection are not only troublesome, but also
If any of the electric heaters 5 is damaged, there is a risk that the foundation concrete 2 at the mountain pass will freeze if it takes a long time to repair it, and since the electric heater 5 itself is not explosion-proof, it is especially suitable for LNG or In the case of a foundation for a tank 1 containing a flammable liquid such as LPG, the vibrator 4 must be filled with an inert gas such as nitrogen gas to provide an explosion-proof structure, which results in a complicated structure. Not only ゛, but also electric heater 5! Since a space is provided between the electric heater 5 and the foundation concrete 2, the total thermal resistance between the electric heater 5 and the foundation concrete 2 is large, together with the fact that the electric heater 5 itself has an insulating coating. Therefore, there was a problem that the heat transfer coefficient deteriorated. Furthermore, since the surface area of the electric heater 5 itself is small, if the vibrator 4 is made thicker in order to increase the heat transfer area to the base concrete 1 and 2,
Since the space intervening between the electric heater 5 and the foundation concrete 2 becomes wider, there is a problem that the heat transfer efficiency further deteriorates.If the pipe 4 is made thinner in order to solve this problem, the heat transfer efficiency will be further reduced. Since the heating area becomes narrower, a problem arises in which the number of cables must be increased. Furthermore, since the electric heater 5 does not necessarily have a uniform concentration in each part along its length, localized low-temperature and high-temperature areas occur, which increases the internal stress of the foundation concrete 2 and, in the worst case, There was a risk that the occurrence of cracks and damage in the foundation concrete 2 would be promoted.

This invention has been made to solve the above problems.The overall structure is simple and explosion-proof, and the entire base of the tank can be easily maintained at a uniform temperature. The purpose of this invention is to provide a basic antifreeze device for a low-wet liquid tank that is highly reliable in terms of durability and the like.

Below, an embodiment of the present invention will be described with reference to FIGS. 3 to 7.

FIG. 3 is a schematic cross-sectional view showing an example of an IM according to the present invention, and FIG. 4 is a cross-sectional view taken along the line IV-TV, and L
A tank 1o for storing low-temperature liquid such as NG is installed on a foundation-J concrete 12 with a heat insulating concrete 11 in between. The foundation concrete 12 is formed into a short circular shape with a larger diameter than the tank 10, and is arranged so that the ci, -ζ blade part protrudes to the outside of the μ foundation concrete 12 inside, more precisely, on the upper side. Multiple heat vibes 13,
A heat storage vibrator 14 arranged parallel to each heat vibrator 13 is buried horizontally in the darkness, and the end of each heat vibrator 13 protruding from the foundation concrete 12 is adjacent to the foundation concrete 12. The ml that was placed! 15 in warm water.

Here, the melting point or transition temperature of the heat storage vibe 14 is the temperature of the foundation concrete 12 to be maintained.

(for example, about 5° C.) or higher, and any of the substances listed in Table 1 is used as the heat storage material 16.

The hot water tank 15 is a heating source for the foundation concrete 12, and the hot water tank 15 is filled with hot water (for example, 5°C to 40°C) that is higher than the temperature (for example, about 5°C) of the foundation concrete 12 to be maintained. It is circulated and supplied from 17 through a pump 18. Therefore, in each heat vibrator 13, the part immersed in the hot water tank 15 serves as a heating part (evaporation part).
The part buried in the foundation concrete 12 serves as a heat dissipation part (condensation part).

In the above anti-freezing device, since the temperature of the foundation concrete 12 is lower than the hot water in the hot water tank 15, the heat vibrator 13 transfers the heat of drought to the foundation concrete 1-12111! Transport to. In that case, the heat transported by the heat vibrator 13 is transferred to the foundation concrete 12 and the heat storage vibrator 14, so that at the same time as the foundation concrete 12 is heated, a part of the heat transferred from the heat vibrator 13 is transferred to the heat storage pipe. The heat storage material 16 enclosed in the heat storage material 14 is stored as latent heat (or apparent latent heat). This kind of heat transfer is done by heat vibrator 13 and foundation concrete 12.
This will continue as long as there is a temperature gradient between the hot water tank 15 and the heat storage pipe 14. Therefore, by appropriately controlling the temperature of the hot water in the hot water tank 15, the foundation concrete 12 will be kept at a constant temperature (for example, about 5°C). ) and prevent it from freezing.In addition, in the above device, by burying the heat storage pipe 14 in the foundation concrete 12, the temperature (or pressure) of the liquid stored in the tank 10 can be increased. ) fluctuations, changes in outside temperature, or changes in soil vA degree, and as a result, foundation concrete 1 and 12
When it is cooled all at once, the foundation concrete 12 radiates heat and the heat is transferred to the heat storage material 16! 11 When the temperature drops to the solution point or dislocation flux, a change in the state of the N heat material 16 occurs,
As a result, the heat storage material 16 releases latent heat, causing heat]
・As it compensates for the lack of heat supply from the pipe 13, the foundation concrete 12 is temporarily cooled, preventing the 81 end of the 1t% concrete 12 from dropping and preventing its freezing. can be prevented. Heat storage I/11 f,
The release of latent heat from the base concrete 12 is due to the heat storage material 1
This occurs when the temperature drops to the melting point or dislocation concentration of heat pipe 1 of hot water boiler 17, etc.
Even if a failure occurs in the heat supply source for 3, the heat storage material 1
6 radiates heat, preventing the temperature of the foundation concrete 12 from dropping and preventing it from freezing.

Furthermore, since the heat pipe 13 has a uniform temperature throughout due to its characteristics, it is possible to uniformly heat the foundation concrete 12 and prevent the occurrence of localized high-temperature areas or low-temperature areas.

Furthermore, the heat pipe 13 does not have a high-temperature part that would cause the liquid in the tank 10 to ignite, and the heat pipe 131 itself has an explosion-proof structure, so special explosion-proof treatment is required as in the case of using a conventional electric heater. Moreover, since the heat pipe 13 has high strength and has no moving parts, it does not necessarily require a protective tube such as a conventional pipe, and can provide a highly reliable antifreeze device. In addition, since the entire outer peripheral surface of the heat pipe 13 is a heat dissipation surface, the heat transfer area for each heat pipe 13 to the foundation concrete 1 and 12 is large. The number of electric heaters can be significantly reduced compared to the number of electric heaters in conventional devices.

Note that the heat pipe 13 and the heat storage pipe 14 do not necessarily have to be arranged on the same plane as shown in FIG. It may be placed on the side. With the configuration shown in FIG. 5, if the soil 19 existing under the foundation concrete 12 drops by one degree for some reason, the heat storage material 16 will change its state and release latent heat. Freezing of the lower upper part 19 can also be prevented.

Further, the heat storage pipe 14 may be provided inside the heat pipe 13. That is, as shown in FIGS. 6 and 7, the heat pipe 13 has a hollow double tube structure, and its center 1i581
11 is filled with Jii thermal material 16 and heat storage pipe 14 is installed here.
, and the outer peripheral side thereof may be used as a heat pipe 13.

Further, the heat storage material 16 in the present invention may be a material having a large specific heat, such as metal or saline solution, in addition to the materials shown in the above embodiments.

As is clear from the above description, according to the antifreeze device of the present invention, a heat storage pipe containing a heat storage material and a heat pipe are buried in foundation concrete, and one end of the heat pipe protruding from the foundation concrete is buried in the foundation concrete. The structure is such that the foundation concrete is heated by the heat transported from the heating source by the heat pipe, and at the same time, a portion of that heat is stored in the heat storage material. Temporary decreases in the amount of heat supplied from the heat pipes can be compensated for by the heat stored in the heat storage material, so changes in the temperature of the foundation concrete can be reduced and the temperature can be maintained at a nearly uniform temperature at all times. Furthermore, according to the antifreeze device of the present invention, it is possible to place the lunar heat source at a location that is far away from the tank, and since the heat pipe itself has a so-called explosion-proof structure, it is possible to place the LNG heat source in the tank.
Even when storing liquefied fuels such as An excellent antifreeze device can be obtained. In addition, the entire outer circumferential surface of a heat pipe is a heat dissipation surface, and the heat transfer area of each heat pipe is large, so the number of heat pipes can be reduced, which is #1 in this respect. 4f! can be made simple. Furthermore, heat pipes have an almost uniform temperature throughout the entire base concrete due to their properties, so they can heat the entire foundation concrete uniformly and equalize the temperature, thus preventing the formation of high temperature and low temperature zones within the foundation concrete. This can prevent the generation of thermal stress in the foundation concrete.

[Brief explanation of drawings]

Figure 1 is a schematic cross-sectional view showing an example of a conventional 5 unit, Figure 2
The figure is a sectional view taken along the line ■-■ in FIG. 1, FIG. 3 is a schematic sectional view showing an embodiment of the present invention, and FIG.
5 is a schematic sectional view showing another embodiment of the present invention; FIG. 6 is a sectional view of an example in which a heat storage pipe and a heat pipe are integrally configured in a concentric manner; FIG. 7 is a sectional view taken along the line ■--■ in FIG. 6. 10...Tank, 12...Foundation concrete. 13-... Heat pipe, 14-... Heat storage pipe. 15...kindness, 16...heat storage material. Patent attorney representing applicant Fujikura Electric Cable Co., Ltd.! Takehisa Ta (1 idiot) Figures 1 and 2 Figure 3 Figure 4 +2

Claims (2)

[Claims] (1) Inside the foundation concrete where the low-temperature liquid tank is installed,
A peel pipe and a heat storage pipe containing a heat storage material are buried, one end of the heat pipe is made to protrude outside the foundation concrete 1, and one end of the protruding heat pipe is held. Basic concrete 1
- Basic anti-freezing device for cryogenic liquid tanks, which is located in the heating area above the temperature of -. (2) The basic antifreeze device for a low temperature liquid tank according to claim 1, wherein the heat storage pipe is inserted concentrically into the P1 pipe.