JP4841397B2 - Fuel container - Google Patents

Description

  The present invention relates to a fuel container, and more particularly, to a fuel container for a ship that uses natural gas hydrate (NGH) as a fuel.

Conventionally, a diesel engine installed on the ship is adopted as a main engine of a large ship, and heavy oil is used as the fuel. Some small vessels employ a gasoline engine. However, since every vessel emits air pollutants such as CO ₂ , NOx, and SOx during navigation, control and capital investment to control it (low speed operation, adoption of high-efficiency engines and low exhaust gas engines, etc.) )Is required. Therefore, natural gas energy is attracting attention because of consideration for the global environment.

  As natural gas energy, liquefied natural gas (LNG) is well known, and recently, NGH has attracted attention as a new natural gas energy (see Non-Patent Document 1). NGH is an clathrate hydrate in which natural gas molecules (guests) mainly composed of methane, ethane, propane and the like are incorporated into a cluster of water molecules, and is about 170 under an atmospheric pressure environment of −20 ° C. Since it can contain twice as much gas, it has many advantages over LNG in terms of the entire system of manufacturing, transportation, storage, and gasification. NGH is also attracting attention as clean energy because it emits less carbon dioxide and air pollutants than gasoline.

By the way, a ship that can prevent the outer shell of the fuel tank from being damaged even if the ship's bottom is damaged due to a collision or grounding while navigating the ship, and the problem that the fuel oil in the fuel tank leaks into the sea has been proposed. (See Patent Document 1). In this ship, a double hull consisting of a hull outer shell and a hull inner shell is provided at the lower part of the hull provided in the hull, and a triple hull is provided at the center in the width direction of the hull partitioned from the hull by this double hull. In addition, a fuel tank is provided at the bottom of the Mie ship, and a ballast tank is provided below the fuel tank.
JP 2004-306694 A Mitsui Engineering & Shipbuilding Co., Ltd., “Natural Gas Hydrate (NGH)-Mitsui Engineering & Shipbuilding”, [online], [October 23, 2006 search], Internet <URL: http://www.mes.co.jp/mes_technology /ngh.html>

When using the above-mentioned LNG as the fuel for the ship, it is necessary to store it at a cryogenic temperature of -162 ° C. Therefore, it is preferable to use a dedicated container with a cold insulation structure or a special liquefaction mechanism. Has been.
In addition, when NGH is employed, NGH is stored and stored in a temperature environment that is relatively easy to control, such as −20 ° C., so there is no problem like LNG and fuel handling is relatively easy. However, since NGH is handled as a pellet-like solid, it is difficult to load directly into the fuel tank installed in the ship as shown in Patent Document 1, and the method of loading the container in which the NGH pellets are stored into the ship is preferably adopted. Has been.

  However, when a ship loaded with such fuel containers sinks due to grounding or capsizing, as shown in FIG. 4, only the fuel container 41 leaves the hull 40 and sinks to the seabed while being filled with combustible high-pressure gas. There is a risk of inadvertent drift, which is very dangerous.

  Accordingly, an object of the present invention is to provide a fuel container that is easy to find and recover even if released from the ship due to the sinking of the ship, and has high safety.

  The above object of the present invention is a fuel container loaded on a ship, a fuel storage part for storing natural gas in a hydrate or liquid state, and an abnormality for detecting that the fuel container has been discharged outside the ship. This is achieved by a fuel container comprising a detection sensor and a levitation device for levitating the fuel container released to the sea to the vicinity of the sea surface. According to this, since the fuel container can be levitated to near the sea surface, it can be found visually from above.

  In the present invention, the levitation device preferably includes a contracted floating bag and gas injection means for inflating the floating bag in response to an abnormality signal from the abnormality detection sensor. Here, the levitation device may further include a gas cylinder and inflate the floating bag by injecting the gas in the gas cylinder into the floating bag. The levitation device further includes a gasification device that gasifies the hydrate or liquid natural gas in the fuel storage unit, and injects the gas generated by the gasification device into the buoyancy bag to inflate the buoyancy bag. Good. Further, the levitation device may inflate the buoyancy bag by introducing a hydrate or liquid natural gas boil-off gas in the fuel storage section into the buoyancy bag.

  The fuel container of the present invention preferably further includes a position information transmitter that is attached to the fuel container and transmits a position information signal when the fuel container is discharged out of the ship. According to this, the fuel container can be searched at an early stage using the position information signal as a clue. Here, the fuel container of the present invention preferably further includes a fuel cell that generates power using natural gas in the fuel storage unit, and the position information transmitter is preferably operated by electric power supplied from the fuel cell.

  In the present invention, the natural gas in the fuel storage unit is preferably NGH, but may be LNG.

  As described above, according to the present invention, even when released from the ship due to the sinking of the ship or the like, it is easy to find and collect the fuel container and to provide a highly safe fuel container.

  Hereinafter, preferred embodiments of the present invention will be described in detail with reference to the accompanying drawings.

  FIG. 1 is a schematic diagram showing a configuration of a fuel container according to the first embodiment of the present invention.

  As shown in FIG. 1, the fuel container 10 is loaded on a ship as a detachable fuel tank. The fuel container 10 is a main part of the fuel container 10, and the fuel container 10 is caused by the sinking of the ship. An abnormality detection sensor 12 for detecting that the fuel container 10 has been released to the outside of the ship, a levitation device 13 for levitating the fuel container 10 released to the outside of the ship to near the sea surface, and a sound wave signal when the fuel container 10 is released to the outside of the ship And a fuel cell 15 for supplying electric power to the sound wave transmitter 14.

  NGH is stored in the fuel storage unit 11 of the present embodiment. The fuel storage unit 11 has a fuel supply port 11a, and NGH is taken out from the fuel supply port 11a or filled with NGH. A control valve 11b is provided at the fuel supply port 11a, and the open / closed state of the fuel supply port 11a is controlled by an external signal. The abnormality detection sensor 12 detects that the fuel container 10 has been discharged out of the ship as an abnormal situation, but this detection may be determined when the fuel container 10 has deviated from the fixed position in the ship. It may be determined that the distance from a certain distance is more than a certain distance, or a submerged state may be detected. However, it goes without saying that when the fuel container 10 is replaced, it is necessary to cancel the separation detection by the abnormality detection sensor 12.

  The levitation device 13 includes a contracted floating bag 16, a carbon dioxide gas cylinder 17 filled with carbon dioxide gas, and a gas injector 18 that injects carbon dioxide gas in the carbon dioxide gas cylinder 17 into the floating bag 16. The gas injector 18 preferably has a function of monitoring the pressure in the float bag 16 and stopping gasification when the pressure reaches an optimum pressure or discharging the pressurized portion to the outside. As shown in the figure, the float bag 16 may be stored in a space inside the fuel container 10 partitioned from the fuel storage unit 11, or may be attached to the outside of the fuel container 10. On the other hand, the carbon dioxide gas cylinder 17, the gas injector 18, the sound wave transmitter 14, and the fuel cell 15 need to be stored in a waterproof space in the fuel container 10.

  Usually, the fuel container 10 is fixed at a predetermined position in the ship, and the fuel supply port 11a of the fuel container 10 is connected to a fuel system in the ship. As a result, NGH in the fuel storage unit 11 is appropriately taken out and decomposed into natural gas and water, and then used as fuel for driving the main engine and generator of the ship.

  When the fuel container 10 is released from the ship for some reason, such as ship sinking, grounding, damage to the hull due to collision between ships, capsizing, dropping off due to poor attachment, etc., the abnormality detection sensor 12 detects this state, A signal is output. The control valve 11b that has received the abnormality signal immediately closes the fuel supply port 11a, so that the outflow of NGH and the intrusion of seawater into the fuel storage unit 11 are prevented.

Next, the gas injector 18 that has received the abnormality signal from the abnormality detection sensor 12 starts an operation of sending the carbon dioxide gas in the carbon dioxide cylinder 17 into the floating bag 16. The float bag 16 infused with carbon dioxide gas swells greatly, and generates buoyancy that causes the fuel container 10 to float to near the sea surface. In addition, the sound wave transmitter 14 that has received the abnormality signal from the abnormality detection sensor 12 also starts operation and transmits a predetermined sound wave signal. Therefore, after the accident, the position of the fuel container 10 can be searched using this sound wave signal as a clue. Moreover, since the fuel container 10 is levitating near the sea, it can be discovered visually from above. If NGH is stored, about 80% of the container is water, and considering that it has a specific gravity equivalent to seawater, there is a buoyancy that can substantially lift the weight of the fuel container alone. In this case, the fuel container 10 can be lifted. For example, since the weight of a 20-foot container is about 3 t, if there is about 3 m ³ of carbon dioxide gas, the fuel container 10 can be lifted.

  FIGS. 2A to 2C are schematic views showing the external shape of the expanded bag 16.

  As shown in FIG. 2A, the floating bag 16 may have a shape in which one surface of the fuel container 10 is opened and the entire surface is expanded. As shown in FIG. It may be a shape that wraps around. Furthermore, as shown in FIG. 2C, it may have a shape like an ad balloon connected to the fuel container 10 by a gas supply pipe 19 having tensile strength. The number of the float bags 16 equipped in the fuel container 10 is not particularly limited, and the attachment position and the attachment method are not particularly limited.

  As described above, according to the present embodiment, when the fuel container 10 is released to the outside of the ship, the fuel container 10 can be levitated near the sea surface, and the position of the fuel container 10 can be adjusted by the sonic transmitter 14. Since it can be known, the fuel container 10 can be found and recovered immediately after the accident. Moreover, since the fuel cell 15 is used as a power source of the sonic transmitter 14 and the fuel cell 15 can generate power semipermanently using a large amount of NGH stored in the fuel storage unit 11, the sonic transmitter 14 is also used. An extremely long-term operation is possible, and the signal output can be increased.

  FIG. 3 is a schematic diagram showing the configuration of a fuel container according to the second embodiment of the present invention.

  As shown in FIG. 3, the fuel container 20 is characterized by gasifying NGH stored in the fuel storage unit 11 and injecting the gas into the floating bag 16. Therefore, the fuel container 20 of the present embodiment includes a gasifier 21 that gasifies NGH in the fuel storage unit 11 instead of the carbon dioxide gas cylinder 17 described above. Although high-pressure water is obtained by decomposing NGH, this water may be discharged outside the container or returned to the fuel storage unit 11. Since other configurations are substantially the same as those in the first embodiment, detailed description thereof is omitted.

  As described above, according to the present embodiment, the natural gas obtained by NGH decomposition is used as the gas for inflating the air bag 16 that causes the fuel container 10 to float, and therefore, the same as in the first embodiment. In addition to obtaining operational effects, the carbon dioxide cylinder 17 can be eliminated, and the fuel gas in the fuel container 10 can be effectively utilized.

  The present invention is not limited to the above embodiments, and various modifications can be made without departing from the spirit of the present invention, and these are also included in the scope of the present invention. Needless to say.

  For example, in the above embodiment, NGH is taken as an example of the fuel gas stored in the fuel container 10, but the present invention is not limited to NGH, and LNG is supplied by the fuel container as fuel for ships. Is also possible. When a fuel container for storing LNG is released outside the ship due to the sinking of the ship, etc., it is very dangerous as with NGH. However, when the fuel container according to the present invention is used, it is prompt after an accident as with NGH. It is possible to discover and collect fuel containers. When storing LNG, a large amount of boil-off gas is generated in the fuel container. Therefore, the boil-off gas may be injected into the floating bag 16 in the fuel container storing LNG. According to this, since it is not necessary to positively gasify the fuel gas using the gasifier 21, the gasifier 21 can be omitted. In addition, although not as much as LNG, NGH also generates boil-off gas when it is warmed in seawater for a long time, so the gasifier 21 can also be omitted in NGH.

  Moreover, in the said embodiment, although the carbon dioxide gas was used as gas which inflates a floating bag, and the case where a carbon dioxide gas cylinder was provided was demonstrated, this invention is not limited to this, Not only carbon dioxide gas but nitrogen gas, Industrially general gas such as compressed air can be applied.

  Moreover, although the case where the sound wave transmitter 14 was used as a positional information transmitter was demonstrated in the said embodiment, this invention is not limited to this, Signals, such as a radio signal and an optical signal, can be applied. Is possible.

  Moreover, in the said embodiment, although the fuel cell 15 was used as a power supply of the sound wave transmitter 14, a storage battery may be used.

FIG. 1 is a schematic diagram schematically showing the configuration of a fuel container 10 according to the first embodiment of the present invention. FIGS. 2A to 2C are schematic views showing the external shape of the expanded bag 16. FIG. 3 is a schematic diagram showing the configuration of the fuel container 20 according to the second embodiment of the present invention. FIG. 4 is a schematic diagram for explaining problems with the conventional fuel container.

Explanation of symbols

DESCRIPTION OF SYMBOLS 10 Fuel container 11 Fuel storage part 11a Fuel supply port 11b Control valve 12 Abnormality detection sensor 13 Levitation device 14 Sonic transmitter 15 Fuel cell 16 Floating bag 17 Carbon dioxide gas cylinder 18 Gas injector 19 Gas supply pipe 20 Fuel container 21 Gasification device 40 Hull 41 Fuel container

Claims (6)

  A fuel container loaded on a ship, which stores a natural gas in a hydrate or liquid state, an abnormality detection sensor that detects that the fuel container has been released to the outside of the ship, and a release to the sea And a levitation device for levitating the fuel container to the vicinity of the sea surface.   2. The fuel container according to claim 1, wherein the levitation device includes a deflated buoyancy bag and gas injection means for inflating the buoyancy bag in response to an abnormality signal from the abnormality detection sensor.   The levitation device further includes a gasification device for gasifying hydrate or liquid natural gas in the fuel storage unit, and injecting the gas generated by the gasification device into the buoyancy bag, The fuel container according to claim 2, wherein the fuel container is inflated.   3. The fuel container according to claim 2, wherein the levitation device inflates the buoyancy bag by introducing a hydrate or liquid natural gas boil-off gas in the fuel storage portion into the buoyancy bag.   The fuel according to any one of claims 1 to 4, further comprising a position information transmitter that is attached to the fuel container and transmits a position information signal when the fuel container is released to the outside of a ship. container.   The fuel container according to claim 5, further comprising a fuel cell that generates power using natural gas in the fuel storage unit, wherein the position information transmitter is operated by electric power supplied from the fuel cell.

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