JPH06156581A - Liquefied fuel gas storeroom - Google Patents

Abstract

PURPOSE:To prevent a fire and explosion in a storeroom by providing an inclined water protective plate which is placed on the upper edge of a liquid protective wall along the entire circumference thereof and the upper edge of which is inclined upward toward the interior of said place. CONSTITUTION:A liquefied gas tank 01 where liquefied fuel gas is stored is surrounded by a liquid protective barrier 05. A water protective plate 13 is provided so as to be upwardly inclined toward the inside of the barrier 05 from the upper edge thereof, so that drops of water are collected by the plate 13 to discharge them out of the barrier 05. As a result, an increase in evaporation of gas is prevented and gas temperature on the periphery of the barrier 05 can be kept below limits of inflammability. Consequently, when liquefied fuel leaks out of the storage place due to an earthquake etc., the fuel is diffused upward rapidly and surely, thereby preventing an explosion from taking place.

Description

Detailed Description of the Invention

[0001]

FIELD OF THE INVENTION This invention relates to liquefied fuel gas storage.

[0002]

2. Description of the Related Art LNG (Liquified Nature)
ral Gas) is liquefied by cooling natural gas containing methane as a main component. At the time of liquefaction, all impurities such as sulfur and carbon dioxide in the gas are removed, and it is used for electricity, city gas, etc. Is expanding. By the way, almost all of LNG depends on imports, and landing storages are also constructed in various parts of the country. LNG has a higher ignition temperature (540 ° C.) than other liquid fuels or gas fuels, and has a high mixing ratio (5.0 to 15.0%) with air for combustion, and can be said to be a relatively safe gas. However, the storage is equipped with measures to prevent fires caused by gas leaks such as earthquakes. That is, as shown in the overall perspective view of FIG. 3, the LNG tank 1 is connected with the LNG inflow / outflow pipe 02 for unloading from a tanker and supplying to a consumer. The risk of liquid (gas) leakage due to 03 damage is greatest. Therefore, a liquid collecting pit 04 is provided under the pipe joint 03, and the liquid prevention dike 05 is swirled around the premises including the LNG tank 01.
Even if all of the LNG of the above is leaked, it is possible to prevent it from leaking out of the storage premises. In addition, as a fire extinguishing facility in the event of a fire, a powder extinguishing facility 07, a foaming agent discharging facility 06, etc. are provided to ensure the disaster prevention system on the premises of the storage facility. However, in the event of an earthquake, the leaked LNG in liquid form accumulates at the bottom of the liquid collection pit 04 or the dike 05, and the LNG that is exposed to the temperature and gasified due to temperature rise is lighter than air.
Since it drifts out of the storage, it is extremely dangerous when the mixing ratio with air when it is discharged from the storage is about 5%. Therefore, in the conventional storage, as shown in the vertical sectional view of FIG. 4, the water supply pipe 08 (FIG. 3) equipped with a large number of water curtain nozzles 09 around the liquid barrier 05 is surrounded by a mixture ratio of LNG of 5%.
It is equipped to spread below. That is, the dike 0
The water curtain 01 formed by the fountain from the water curtain nozzle 09 on the lee side of the LNG exhaust gas 011
By letting it pass over the upper end of 0, it diffuses in the sky.

[0003]

By the way, the leaked L
Although NG does not exceed the dike 05, it is expected that the LNG012 gasified by contact with the atmosphere will exceed the dike 05 on the windward side due to the weight effect. It is necessary to prevent such a dangerous state from occurring in advance. As shown in FIG. 5, a water curtain 010 is also stretched from the windward breakwater 05 so that the exhaust gas is diffused to the leeward direction as shown in the figure. However, the water curtain on the leeward side is splashed 01 by the wind.
It becomes 01 and falls onto the low temperature leak LNG, and L
Since it accelerates the evaporation (gasification) of NG, it may rather increase the risk.

The present invention has been proposed in view of such circumstances, and when liquefied fuel in a storage facility leaks due to an earthquake or the like, the liquefied fuel is quickly and reliably diffused above the facility, It is an object of the present invention to provide a safe liquefied fuel gas storage that prevents fires and explosions on the premises.

[0005]

To this end, the present invention provides
In a liquefied fuel gas storage that is formed by surrounding a liquefied gas tank for storing liquefied fuel gas by a levee, the liquified fuel tank is laid along the entire circumference at the upper end of the levee, with the upper end facing the premises It is characterized by having an inclined waterproof plate that slopes up.

[0006]

According to this structure, the falling water drops are collected and discharged to the outside of the liquid barrier. From the experimental results, it has been confirmed that the gasified LNG diffuses to the windward side due to the gravitational effect when the water curtain on the windward side does not exist at a wind speed of 3 m / s or less. By the way, the experimental result of the amount of water droplets splashed by the water curtain inside the liquid barrier at a wind speed of 3 m / s is as shown in Fig. 2. Is almost zero.

[0007]

DETAILED DESCRIPTION OF THE PREFERRED EMBODIMENTS An embodiment of the present invention will be described with reference to the drawings. FIG. 1 is a longitudinal sectional view thereof, and FIG. 2 is a relationship between a distance from a dike and a unit area, and a water drop drop amount per unit time in FIG. FIG.

In the above figure, the same reference numerals as those in FIGS. 3 to 5 indicate the same members as those in the figures. First, in FIG. 1, from the top of the liquid barrier 05 toward the upper diagonal inside of the liquid barrier. The waterproof plate 13 is installed, and the water drops 0101 are collected by the waterproof plate 13 and discharged to the outside of the liquid barrier 05. When there is no water curtain 010 on the windward side, the exhaust gas diffuses to the windward side when the wind speed is about 3 m / s or less. In that case, most of the water droplets 0101 fall from the liquid barrier 05 within a range of about 5 m, so that the width of the waterproof plate 13 need only be about 5 m.

Incidentally, in FIG. 1, the height H of the levee is
_B = 10m, the water curtain the height of the H _S = 10m, wind speed 3m / s
In the case of, the relationship between the distance x of the dike and the drop amount of water drop Qg / m ² s was determined by an experiment, and the results shown in FIG. 2 were obtained. According to this, it was found that the amount of water droplets dropped was about 5 m in the leeward side of the levee from the levee and the amount of water droplets dropped to the premises was 5 m or more downwind.

[0010]

According to such an inclined waterproof plate, the water curtain promotes gas diffusion, prevents water droplets from falling into the premises, and discharges them outside the premises. . As a result, it is possible to prevent the evaporation of gas from increasing and to suppress the gas concentration around the liquid barrier to a bottom temperature below the flammability limit.

In short, according to the present invention, in a liquefied fuel gas storage in which a liquefied gas tank for storing liquefied fuel gas is surrounded by a levee, the upper end of the levee is provided along the entire circumference thereof. In the event of an earthquake, etc.
In the case where the liquefied fuel in the storage facility leaks out, it is quickly and surely diffused to the sky above the facility to obtain a safe liquefied fuel gas storage facility that prevents the occurrence of fire and explosion in the facility. Is extremely useful in industry.

[Brief description of drawings]

FIG. 1 is an overall vertical cross-sectional view of a liquefied fuel gas storage showing an embodiment of the present invention.

FIG. 2 is a diagram showing a distance from the liquid barrier in FIG. 1, a unit area, and a drop amount of water droplets per unit time.

FIG. 3 is an overall perspective view of a conventional liquefied fuel gas storage.

FIG. 4 is a vertical sectional view showing the operation of the water curtain nozzle in FIG.

5 is a vertical cross-sectional view showing the action of the water curtain nozzle on the windward side in FIG. 3. FIG.

[Explanation of symbols]

 01 LNG tank 02 LNG in / out pipe 03 Pipe joint 04 Liquid collecting pit 05 Levee dike 06 Foaming agent discharge facility 07 Powder extinguishing facility 08 Water supply pipe 09 Water curtain nozzle 010 Water curtain 011 Exhaust gas 012 Leak LNG 13 Inclined waterproof plate

Claims (1)

[Claims] 1. A liquefied fuel gas storage in which a liquefied gas tank for storing liquefied fuel gas is surrounded by a levee, and the liquefied fuel tank is provided along the entire circumference at the upper end of the levee, and the upper end is the same storage. A liquefied fuel gas storage facility having an inclined waterproof plate that inclines upward toward the site.