JP5010901B2 - Ship - Google Patents

Description

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

Conventionally, diesel engines have been adopted as the main engine of the ship, and heavy oil is used as the fuel. However, since air pollutants such as CO ₂ , NOx, and SOx are discharged, it is necessary to suppress it. Control and capital investment (low speed operation, adoption of high efficiency engine and low exhaust gas engine, etc.) are required. In addition, if heavy fuel oil leaks to the sea due to collision or grounding, serious environmental destruction may occur. Therefore, natural gas energy has been attracting attention as a fuel in consideration of the global environment (see Non-Patent Document 1).

  As natural gas energy, liquefied natural gas (LNG) is well known, but since LNG is produced and stored at an extremely low temperature of −162 ° C., it has a problem that it is very difficult to handle. Further, there is a problem that LNG is evaporated little by little due to a rise in the temperature of the tank and a large amount of boil-off gas is generated. In particular, when the ship does not move for 2 to 3 days, the pressure inside the tank becomes very high, so it is necessary to remove the boil-off gas by burning in a boiler, etc., and consuming fuel unnecessarily. As a result, the cost increases.

Therefore, recently, NGH has attracted attention as a new natural gas energy. 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.
Mitsui Engineering & Shipbuilding Co., Ltd., “Natural Gas Hydrate (NGH)-Mitsui Engineering & Shipbuilding”, [online], [searched on November 21, 2006], Internet <URL: http://www.mes.co.jp/mes_technology /ngh.html>

  When using the above-mentioned NGH as a ship fuel, NGH is stored and stored under a temperature environment of -20 ° C that is relatively easy to control, so there is no problem like LNG and the handling of the fuel is relatively easy. It is. Furthermore, even if NGH flows out to the sea due to a collision or the like, since NGH is only decomposed into fuel gas and water, there is almost no impact on the environment. However, the decomposition of NGH produces a large amount of water in addition to natural gas, and the production rate of water is about 80% by volume with respect to NGH. Become. Fuel is mainly consumed during navigation of the ship, and such a large amount of water is generated as the fuel is consumed. Therefore, a new device for effectively utilizing this water in the ship is desired.

  Accordingly, an object of the present invention is to provide a ship that can use NGH as a fuel and can effectively utilize water obtained by decomposition of NGH.

  The above object of the present invention is driven by an NGH tank storing NGH, an NGH decomposition apparatus that decomposes NGH supplied from the NGH tank to generate fuel gas and NGH decomposition water, and the fuel gas. A main engine that uses the NGH decomposition water as cooling water, and a water storage tank that stores the NGH decomposition water used as cooling water in the main engine, and the NGH decomposition water in the water storage tank is used as domestic water. Achieved by a ship characterized in that it is supplied as

  While navigating the ship, the fuel of the main engine is required, but the main engine needs to be cooled, so the fuel gas obtained by the decomposition of NGH is used as the driving fuel for the main engine and the decomposition of NGH. By using the relatively low-temperature NGH decomposition water produced in large quantities along with the cooling of the main engine, it is possible to effectively use the NGH decomposition water and improve the performance of the ship. Moreover, since NGH decomposition | disassembly water is used as a cooling water of a main engine, it is stored in a water storage tank, and is used suitably as domestic water, Therefore NGH decomposition | disassembly water can be used effectively as a refrigerant | coolant. In addition, since NGH decomposition water is always generated during the navigation of the ship, a relatively large water storage tank, which was necessary for conventional ships, is no longer necessary, and the space inside the ship can be used effectively. Such time and cost can be reduced. In addition, it is possible to use a large amount of domestic water in various situations, and it is possible to improve the life of the ship and improve the life of the ship equipment.

  In the present invention, it is preferable to use the NGH decomposition water as the primary cooling water of the main engine, and it is particularly preferable to use seawater as the primary cooling water of the main engine separately from the NGH decomposition water. According to this, the cooling capacity by the secondary cooling water of the main engine can be increased, and further performance improvement of the ship can be achieved.

  In the present invention, the NGH decomposition water is preferably used as secondary cooling water for the main engine. According to this, it is not necessary to circulate and use secondary cooling water, and new cooling water is always used, so that it is possible to improve cooling efficiency and no replenishment work of secondary cooling water by evaporation or the like is required. It becomes. Therefore, the NGH decomposition water can be further effectively used and the performance of the ship can be improved.

  In the present invention, it is preferable to further include an on-board air conditioning system, wherein the NGH decomposition water is preferably used as cooling water for the air conditioning system, and after the NGH decomposition water is used as cooling water for the air conditioning system, It is particularly preferable to use it as cooling water. According to this, since NGH decomposition water is used as cooling water for an air conditioning system, further effective utilization of NGH decomposition water can be achieved. In particular, NGH decomposition water as a refrigerant is used in the first stage air conditioning system, and then used in the next stage gas engine, and then stored in a water storage tank. Therefore, NGH decomposition water should be used extremely efficiently as refrigerant and domestic water. Can do.

  As described above, according to the present invention, it is possible to provide a ship that uses NGH as a fuel and effectively uses water obtained by decomposition of NGH.

  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 the configuration of a ship according to the first embodiment of the present invention.

  As shown in FIG. 1, this ship 10 is generated by an NGH tank 11 in which NGH is stored, an NGH decomposition apparatus 12 that decomposes NGH supplied from the NGH tank 11 into fuel gas and water, and an NGH decomposition apparatus 12. A buffer tank 13 that temporarily stores the generated fuel gas, a gas engine 14 as a main engine driven by the fuel gas, a screw 15 that is rotated by the power of the gas engine 14, and a gas facility 16 in the ship. ing. The ship 10 also includes a buffer tank 17 that temporarily stores water generated by the NGH decomposition device 12 (hereinafter referred to as NGH decomposition water), first to third heat exchangers 18, 19, and 20, The air conditioning system 21 in the ship that exchanges heat with the other heat exchanger 18 and the NGH decomposition water that has passed through the first and second heat exchangers 18 and 19 store water for use as domestic water in the ship. And a tank 22.

  FIG. 2 is a schematic diagram showing the configuration of the NGH decomposition apparatus 12.

  As shown in FIG. 2, the NGH decomposition apparatus 12 includes an NGH decomposition tank 101 for decomposing a pellet-shaped NGH (NGH pellet) 100 supplied from the NGH tank 11, and warm water for NGH decomposition in the NGH decomposition tank 101. And a nozzle 102 for spraying from above the NGH pellet 100. Although it does not specifically limit as warm water for NGH decomposition | disassembly, What heated NGH decomposition | disassembly water with the water heater 12a can be circulated and used. The water heater 12a in this case may be a gas heater that uses fuel gas obtained by NGH decomposition, or may be a heat exchanger that heats NGH decomposition water by exchanging heat with seawater. Alternatively, an electric water heater may be used. In particular, when seawater is used, energy consumption can be suppressed because energy for heating is unnecessary. By spraying warm water on the NGH pellet 100, the NGH pellet 100 is dissolved, and fuel gas and water are generated. The water obtained at this time is cold water, and the water temperature is −5 to 10 ° C., which is sufficiently lower than room temperature. A net 103 is provided inside the NGH decomposition tank 101, and the NGH pellet 100 and the NGH decomposition water 104 in the NGH decomposition tank 101 are separated vertically by this net 103. The fuel gas generated in the NGH decomposition tank 101 is taken out from the gas discharge port 101 a provided above the NGH decomposition tank 101, and the water 104 generated in the NGH decomposition tank 101 is provided below the NGH decomposition tank 101. It is taken out from the drain port 101b.

  As shown in FIG. 1, the fuel gas generated by the NGH decomposition device 12 is supplied to the gas engine 14 through the buffer tank 13 and is used as a driving fuel for the gas engine 14, and is also used as gas in a ship such as a gas kitchen. It is also supplied to the facility 16.

  On the other hand, the NGH decomposition water generated as a secondary by the NGH decomposition apparatus 12 is supplied to the first heat exchanger 18 through the buffer tank 17 to cool the secondary cooling water of the air conditioning system 21. Used as The NGH decomposition water that has passed through the first heat exchanger 18 and has risen in temperature due to heat exchange is further supplied to the second heat exchanger 19 and used as primary cooling water for cooling the secondary cooling water of the gas engine 14. . Here, seawater is normally used as the primary cooling water for the gas engine 14, and the secondary cooling water is cooled by heat exchange with the seawater by the third heat exchanger 20, but as in the present embodiment. Further, by using NGH decomposition water as primary cooling water, it is possible to improve the cooling capacity of the gas engine 14 and reduce costs by stopping the use of seawater. Moreover, since the NGH decomposition water is used for cooling the secondary cooling water after being once cooled by seawater, an extreme temperature rise of the NGH decomposition water can be suppressed. In addition, since NGH is decomposed during operation of the gas engine, which is a timing that requires cooling of the gas engine, and NGH decomposition water is generated, NGH decomposition water is used as the primary cooling water for the gas engine. Effective use of water can be achieved.

  The NGH decomposition water that has passed through the second heat exchanger 19 and further increased in temperature by heat exchange is stored in the water storage tank 22 as domestic water. The water storage tank 22 does not need to be as large as a conventional water storage tank that stores all the water for daily use during navigation, and the size of the water storage tank 22 is the amount of NGH decomposition water supplied and consumed from the NGH decomposition device 12. And should be determined. Thereafter, the water in the water storage tank 22 is appropriately taken out as domestic water. Specifically, it is supplied as drinking water through the water purifier 23, or used for toilets, baths, washing, inboard cleaning, and the like.

  As described above, according to the present embodiment, the fuel gas obtained from the NGH decomposition device 12 is used as the fuel for the gas engine 14, and the NGH decomposition water obtained from the NGH decomposition device 12 is used as the primary cooling water for the gas engine 14. Therefore, it is possible to effectively use cold water which is a by-product of NGH. As a result, the cooling efficiency of the gas engine 14 can be improved, and the performance of the ship can be improved.

  In addition, if the ship is anchored at the port, the water supplied from the facility in the port can be used as it is, but only water in the water storage tank can be relied on during navigation. However, because too large water storage tanks are wasted space in the ship, the use of fresh water is restricted by the use of relatively small tanks in conventional ships, and various types of water are used depending on the application. I came. For example, drinking water was loaded at a port and stored in a dedicated tank. In addition, fresh water made from seawater, rainwater, and middle water reprocessed from wastewater were used for toilets, baths, laundry, and ship cleaning. In addition, seawater was used for the primary cooling water of the main engine, cleaning water on the deck, fire extinguishing water in the event of a fire. However, according to the present embodiment, the NGH decomposition water that is always generated during navigation is used as domestic water in the ship, so that a large storage tank is not necessary, and a large amount of fresh water is variously used. Can be used in various situations, and can improve the life of the ship and improve the life of the ship equipment.

  Moreover, according to this embodiment, since NGH decomposition water is used also as cooling water of an air conditioning system, the further effective utilization of NGH decomposition water can be aimed at. In particular, NGH decomposition water is used as cooling water for the first-stage air conditioning system, and then used as cooling water for the next-stage gas engine, and then stored in a storage tank as domestic water. The NGH-decomposed water can be used extremely efficiently as a refrigerant and domestic water.

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

  As shown in FIG. 3, this ship 30 uses a part of NGH decomposition water that has passed through the heat exchanger 18 and exchanged heat with the air conditioning system 21 as hot water for NGH decomposition. Since other configurations are the same as those of the first embodiment, detailed description thereof is omitted. According to this embodiment, NGH decomposition water whose temperature has been increased by heat exchange can be used, and a heater for NGH decomposition can be dispensed with.

  FIG. 4 is a schematic diagram showing the configuration of a ship according to the third embodiment of the present invention.

  As shown in FIG. 4, this ship 40 uses a part of NGH decomposition water that has passed through the heat exchanger 19 and exchanged heat with the gas engine 14 as hot water for NGH decomposition. Since other configurations are the same as those of the first embodiment, detailed description thereof is omitted. According to the present embodiment, as in the second embodiment, it is possible to use the NGH decomposition water whose temperature has been further increased by heat exchange, and to eliminate the need for a heater for NGH decomposition.

  FIG. 5 is a schematic diagram showing a configuration of a ship according to the fourth embodiment of the present invention.

  As shown in FIG. 5, the ship 50 is characterized in that the NGH decomposition water is used as it is as the secondary cooling water of the gas engine 14. The NGH decomposition water that has passed through the first heat exchanger 18 as the cooling water of the air conditioning system 21 and has increased in temperature due to heat exchange is supplied to the water storage tank 22 and also to the gas engine 14. Used as secondary cooling water. The secondary cooling water is cooled by heat exchange with seawater by the (third) heat exchanger 20, but in this embodiment, NGH decomposition water can always be supplied as secondary cooling water for the gas engine 14. Therefore, most of the secondary cooling water after heat exchange is drained and is always replenished with new cooling water.

  As described above, according to the present embodiment, the NGH decomposition water is used as the secondary cooling water of the gas engine 14, and therefore it is not necessary to circulate and use the secondary cooling water. Cooling efficiency can be improved by use, and replenishment of cooling water by evaporation or the like is not necessary. Therefore, the NGH decomposition water can be further effectively used and the performance of the ship can be improved.

  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, the gas engine 14 is used as the main engine of the ship, but a gas turbine can also be used. Also in the gas turbine, NGH decomposition water can be used as the primary cooling water or the secondary cooling water.

FIG. 1 is a schematic diagram schematically showing the configuration of a ship according to the first embodiment of the present invention. FIG. 2 is a schematic diagram showing the configuration of the NGH decomposition apparatus 12. FIG. 3 is a schematic diagram schematically showing the configuration of a ship according to the second embodiment of the present invention. FIG. 4 is a schematic diagram schematically showing the configuration of a ship according to the third embodiment of the present invention. FIG. 5 is a schematic diagram schematically showing the configuration of a ship according to the fourth embodiment of the present invention.

Explanation of symbols

DESCRIPTION OF SYMBOLS 10 Ship 11 Tank 12 NGH decomposition | disassembly apparatus 12a Water heater 13 Buffer tank 14 Gas engine 15 Screw 16 Gas equipment 17 Buffer tank 18 1st heat exchanger 19 2nd heat exchanger 20 3rd heat exchanger 21 Air conditioning system 22 Water storage tank 23 Water purifier 30 Ship 40 Ship 50 Ship 100 NGH pellet 101 NGH decomposition tank 101a Gas discharge port 101b Drain port 102 Nozzle 103 Net 104 NGH decomposition water

Claims (3)

An NGH tank in which NGH is stored;
An NGH decomposition apparatus that decomposes NGH supplied from the NGH tank to generate fuel gas and NGH decomposition water;
An onboard air conditioning system using the NGH decomposition water as cooling water;
A main engine driven by the fuel gas and using the NGH decomposition water used as cooling water in the air conditioning system as cooling water ;
A water storage tank for storing the NGH decomposition water used as the cooling water in the main engine,
A ship characterized by supplying the NGH decomposition water in the water storage tank as domestic water.   The ship according to claim 1, wherein the NGH decomposition water is used as a primary cooling water for the main engine. Separately from the NGH decomposition water, seawater is used as the primary cooling water for the main engine, and the secondary cooling water for directly cooling the main engine is further cooled by the NGH decomposition water after being cooled by the seawater. ship according to claim 2, characterized in that that.

Images