JP4999429B2 - 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.

  Further, in conventional ships, seawater is used in various scenes such as primary engine primary cooling water, toilet washing water, and deck cleaning water. Seawater is assembled by a pump from a seawater inlet called a sea chest provided at the bottom of the ship, and sent to various places through piping of the seawater system. However, in the conventional ship, there is a problem that many marine organisms adhere to the sea chest and the inhalation of seawater is hindered.

  Accordingly, an object of the present invention is to provide a ship that uses NGH as a fuel and that can effectively use water obtained by decomposition of NGH and can prevent problems in the seawater system due to adhesion of marine organisms. There is.

  The object of the present invention is to provide 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, and a main drive driven by the fuel gas. This is achieved by a ship comprising an engine, a sea chest provided at the bottom of the hull, and a water injection mechanism for injecting the NGH decomposition water into the sea chest.

  According to the present invention, when fresh water is injected into the sea chest and the sea chest is filled with fresh water, activation of marine organisms attached to the sea chest can be suppressed, and the sea chest It is possible to prevent clogging of the seawater inlet due to a large amount of living organisms. Moreover, the removal work of the marine organism adhering in the sea chest can be made unnecessary. Furthermore, when the relatively low-temperature NGH-decomposed water obtained by NGH decomposition is used as the sea chest injection water as it is, adhesion of marine organisms adapted to sea areas with relatively high water temperatures can be sufficiently suppressed. .

  In the present invention, it is preferable to use seawater in the sea chest mixed with the NGH decomposition water by injection of the NGH decomposition water as primary cooling water for the main engine. Since NGH-decomposed water is fresh water having a relatively low temperature, when it is injected into the sea chest, the sea water in the sea chest has a low salinity and a low temperature. Therefore, when such seawater is pumped up and used, not only can the progress of the corrosion of the seawater system be suppressed, but the cooling capacity of the main engine can be further increased, and further improvement of the performance of the ship can be achieved. Can do. In addition, by supplying sea chest injection water to the sea chest that is the sea water intake of this sea water system, it is possible to suppress adhesion of marine organisms that are particularly sensitive to low temperatures, and to prevent troubles in the main engine. it can.

  In the present invention, it is preferable that the NGH decomposition water is used as primary cooling water for the main engine, and the NGH decomposition water used as the primary cooling water in the main engine is poured into the sea chest. 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. In addition, since the NGH decomposition water after being used as cooling water for the main engine becomes very high in temperature, the use of this as sea chest injection water suppresses the attachment of marine organisms that are particularly sensitive to high temperatures. Can do.

  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. Moreover, since the NGH decomposition | disassembly water after using as secondary cooling water becomes very high temperature, adhesion of a marine organism can be further suppressed by using this as sea chest injection water.

  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 cools the secondary cooling water of the gas engine 14 and the buffer tank 17 that temporarily stores water generated by the NGH decomposition device 12 (hereinafter referred to as NGH decomposition water) by heat exchange with seawater. Heat exchanger 20 and a water storage tank 22 for storing NGH decomposition water as domestic water in the ship.

  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, you may circulate and use the NGH decomposition | disassembly water heated with the water heater, and use the NGH decomposition | disassembly water which raised the temperature by heat exchange with seawater. May be. Moreover, you may use the NGH decomposition | disassembly water which raised the temperature by the heat exchange between the below-mentioned air conditioning system or a gas engine. 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 via the buffer tank 13 and is used as a driving fuel for the gas engine 14, and in a ship such as a gas kitchen. It is also supplied to the gas facility 16.

  On the other hand, the NGH decomposition water generated by the NGH decomposition apparatus 12 is supplied to the water storage tank 22 through the buffer tank 17 and stored as domestic water in the ship. 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. The water in the water storage tank 22 is also used as sea chest pouring water supplied into the sea chest.

  FIG. 3 is a schematic diagram showing an external configuration of a hull bottom portion provided with a sea chest.

  As shown in FIG. 3, a rudder 31 and a screw (propeller) 15 are provided at the rear of the hull of the ship 10, and a sea chest 24 is provided on the bottom of the ship slightly closer to the bow. The sea chest 24 is a recessed space that is slightly wider than the actual seawater inlet 32, and a mesh lattice 33 for preventing inhalation of foreign matters is provided in the opening. A seawater system pipe 34 constituting a seawater inlet 32 is provided in the back of the sea chest 24, and seawater is sucked into the pipe by a seawater pump 35. A fresh water injection pipe 36 is also provided in the back of the sea chest 24, from which fresh water is injected into the sea chest 24. Since the sea chest 24 is always located below the sea surface, even if the net lattice 33 is provided, marine organisms such as shellfish, seaweeds, and algae easily attach through the net lattice 33. However, as in this embodiment, NGH-derived water is used as sea chest infusion water, and water is poured into the sea chest 24, so that sea water and fresh water are mixed to reduce the salt concentration of sea water in the sea chest. Alternatively, fresh water, which has a lower specific gravity than seawater due to the salt concentration, is filled in the sea chest, so that the activation of marine organisms can be prevented, and a large amount of marine organisms adhere to the sea chest 24. The clogging of the seawater inlet 32 can be prevented. Therefore, it is possible to eliminate the removal work of marine organisms in the sea chest 24.

  The injection of fresh water is preferably while the ship 10 is anchored, but may be during navigation. In the case of berthing, since the sea chest 24 is filled with fresh water, the effect of suppressing attachment of marine organisms is great. On the other hand, while sailing, it is thought that the effect as when anchored is not obtained, but during navigation, NGH decomposition water is generated at any time due to fuel consumption and cannot be stored in the water storage tank. Since the surplus is simply discarded, it is possible to suppress the adhesion of marine organisms if it is discarded via the sea chest in such a case. Of course, it is possible not only to supply NGH decomposition water to be discarded, but also to supply it actively into the sea chest 24 during navigation.

  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 sea chest injection water. Water which is a by-product of NGH can be effectively utilized. Thereby, activation of marine organisms can be suppressed and clogging of the seawater inlet 32 due to a large amount of marine organisms adhering to the sea chest 24 can be prevented. Therefore, it is possible to eliminate the removal work of marine organisms in the sea chest 24.

  In addition, according to the present embodiment, NGH decomposition water that is always generated during navigation is also used as domestic water in the ship, so a large water tank is not necessary, and a large amount of fresh water is used. It can be used in various situations and can improve the life of the ship and the life of the ship equipment.

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

  As shown in FIG. 4, the ship 40 is characterized in that the NGH decomposition water generated by the NGH decomposition device 12 is supplied as it is into the sea chest 24 through the buffer tank 17 as sea chest injection water. That is, in this embodiment, relatively low-temperature water obtained by NGH decomposition is used as the sea chest injection water. 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 NGH decomposition water obtained from the NGH decomposition apparatus 12 is used as the sea chest injection water, so that water that is a by-product of NGH can be effectively used. In particular, in the case of a ship navigating in a warm sea area, marine organisms adapted to a relatively high water temperature adhere, so by using the low-temperature NGH decomposition water opposite to this as the sea chest injection water, Activation of marine organisms can be further suppressed, and clogging of the seawater inlet due to a large amount of marine organisms adhering to the sea chest can be prevented. Moreover, if relatively low-temperature NGH decomposition water is injected into the sea chest 24, the sea water in the sea chest 24 has a low salinity and a low temperature. As well as suppressing the progress of the engine, the cooling capacity of the main engine can be further increased, and the performance of the ship can be further improved.

  Further, since the pressure in the NGH decomposition apparatus 12 is very high, if the high-pressure water obtained from the NGH decomposition apparatus 12 is used as it is and is supplied into the sea chest as high-pressure jet water, the sea adhering in the sea chest is It is also possible to remove living organisms by blowing them away with water pressure.

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

  As shown in FIG. 5, this ship 50 is characterized in that it is used not only as a refrigerant for the air conditioning system 21 but also as primary cooling water for the gas engine 14. Therefore, the ship 50 further includes the first and second heat exchangers 18 and 19 and an air conditioning system 21 in the ship that performs heat exchange between the first heat exchanger 18 and the third heat exchanger 18 and 19. The heat exchanger 20 performs heat exchange between the secondary cooling water of the gas engine 14 and seawater.

  The NGH decomposition water generated as a secondary by the NGH decomposition apparatus 12 is supplied to the first heat exchanger 18 via the buffer tank 17 and used as the primary cooling water for cooling the secondary cooling water of the air conditioning system 21. It is done. 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, the combined use of NGH decomposition water as the primary cooling water can improve the cooling capacity of the gas engine 14. Moreover, since NGH decomposition water is produced | generated at the timing which needs cooling of a gas engine, effective utilization of NGH decomposition water can be aimed at by using NGH decomposition water as primary cooling water.

  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. 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.

  On the other hand, the NGH decomposition water that has passed through the second heat exchanger 19 and further increased in temperature by heat exchange is also supplied into the sea chest as sea chest injection water. That is, in this embodiment, relatively high-temperature water obtained by heat exchange is used as the sea chest injection water. 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 NGH decomposition water obtained from the NGH decomposition apparatus 12 is used as the sea chest injection water, so that water that is a by-product of NGH can be effectively used. In particular, in the case of a ship navigating in a cold sea area, marine organisms adapted to a relatively low water temperature are attached. Therefore, by using high-temperature NGH-decomposed water opposite to this as sea chest injection water, It becomes possible to further suppress the activation of living organisms. Furthermore, even if a ship navigates in a warm sea area, it is possible to suppress the activation of marine organisms adapted to a relatively high water temperature when sufficiently high-temperature sea chest injection water is used. .

  Moreover, since the pressure in the NGH decomposition apparatus 12 is very high, after the high-pressure water obtained from the NGH decomposition apparatus 12 is heated to high temperature by heat exchange with the air conditioning system 21 and the gas engine 14, this is used as high-pressure jet water. If supplied into the sea chest, marine organisms adhering to the sea chest can be blown away by water pressure and removed.

  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 used as sea chest injection water. The NGH-decomposed water can be used extremely efficiently as a refrigerant and domestic water.

  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 or seawater can be used as the primary 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 showing the configuration of the rear part of the hull, particularly the sea chest. FIG. 4 is a schematic diagram schematically showing the configuration of a ship according to the second embodiment of the present invention. FIG. 5 is a schematic diagram schematically showing the configuration of a ship according to the third embodiment of the present invention.

Explanation of symbols

DESCRIPTION OF SYMBOLS 10 Ship 11 NGH tank 12 NGH decomposition | disassembly apparatus 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 24 Sea chest 31 Rudder 32 Seawater inlet 33 Net lattice 34 Seawater system piping 35 Seawater pump 36 Fresh water injection pipe 40 Ship 50 Ship 100 NGH pellet 101 NGH decomposition tank 101a Gas outlet 101b Drain outlet 102 Nozzle 103 Net 104 NGH Cracked water

Claims (3)

An NGH tank in which NGH as navigation fuel is stored;
An NGH decomposition apparatus that decomposes the NGH supplied from the NGH tank to generate fuel gas and NGH decomposition water;
A main engine driven by the fuel gas;
A sea chest at the bottom of the hull,
A water injection mechanism for injecting the NGH decomposition water into the sea chest ,
A marine vessel using seawater in the sea chest mixed with the NGH decomposition water by injection of the NGH decomposition water as primary cooling water for the main engine . An NGH tank in which NGH as navigation fuel is stored;
An NGH decomposition apparatus that decomposes the NGH supplied from the NGH tank to generate fuel gas and NGH decomposition water;
A main engine driven by the fuel gas;
A sea chest at the bottom of the hull,
A water injection mechanism for injecting the NGH decomposition water into the sea chest ,
Using the NGH decomposition water as primary cooling water for the main engine,
A ship characterized by pouring the NGH decomposition water used as the primary cooling water in the main engine into the sea chest . The ship according to claim 2 , further comprising an air conditioning system in the ship, wherein the NGH decomposition water is used as a primary cooling water for the main engine after being used as a cooling water for the air conditioning system.

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