Ship

Abstract

To provide a ship capable of making a dead space resulting from storing carbon dioxide recovered from exhaust gas from an engine smaller than a conventional technology.SOLUTION: A ship comprises: an engine which exhausts gas containing a carbon dioxide when the engine operates; a recovery part which recovers the carbon dioxide from the gas exhausted from the engine; a liquefaction part which liquefies the recovered carbon dioxide; and a storage tank which stores the liquefied carbon dioxide. The storage tank is a ballast tank.SELECTED DRAWING: Figure 1

Description

Technical Field

[0001] The technology of the present disclosure relates to ships.

Background Art

[0002] As a measure against climate change, decarbonization is an urgent task in the maritime industry. Therefore, as a means of realizing a zero-emission ship, recovering carbon dioxide on board the ship is considered. When recovering carbon dioxide on board, it is necessary to store the recovered carbon dioxide on board.

[0003] Patent Document 1 discloses an ammonia ship as a decarbonized ship. The ammonia fuel ship includes a spray for spraying water at a location where ammonia may leak, a recovery means for recovering water that has absorbed the ammonia gas leaked at the location, and a storage tank for storing the recovered ammonia water. As the storage tank, a ballast tank is used. A ballast tank is a tank for storing ballast water (i.e., seawater) for adjusting the draft and inclination of the hull.

Prior Art Documents

Patent Documents

[0004]

Patent Document 1

Summary of the Invention

Problems to be Solved by the Invention

[0005] When storing the recovered carbon dioxide on board, a storage tank for this purpose is required. However, the area where the storage tank is arranged becomes a dead space that is not used for anything other than storing carbon dioxide.

[0006] In an ammonia fuel ship, the leaked ammonia gas is absorbed by water, and the water that has absorbed the ammonia gas is stored in a storage tank. Therefore, only ammonia cannot be stored in the storage tank.

[0007] The technology of the present disclosure aims to provide a ship that can reduce the dead space generated for storing carbon dioxide recovered from the exhaust gas of an engine, compared to the prior art.

Means for Solving the Problems

[0008] A ship according to a first aspect of the technology of the present disclosure includes an engine that discharges a gas containing carbon dioxide when operating, a recovery unit that recovers the carbon dioxide from the gas discharged from the engine, a liquefaction unit that liquefies the recovered carbon dioxide, and a storage tank that stores the liquefied carbon dioxide, and the storage tank is a ballast tank.

Advantages of the Invention

[0009] The first aspect of the technology of the present disclosure can reduce the dead space generated for storing carbon dioxide recovered from the exhaust gas of an engine, compared to the prior art.

Brief Description of the Drawings

[0010]

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Embodiments for Carrying Out the Invention

[0011] Hereinafter, embodiments of the technology of the present disclosure will be described with reference to the drawings.

[0012] [First Embodiment] FIG. 1 is a schematic cross-sectional view of an example of a ship 10 according to the first embodiment. As shown in FIG. 1, when the ship 10 operates, it discharges a gas containing carbon monoxide, hydrocarbons, nitrogen compounds, particulate matter, carbon dioxide, etc., and rotates a propeller 12M via a transmission mechanism (not shown). The ship 10 includes an engine 11, a recovery device 14A that recovers carbon dioxide from the exhaust gas led out from the engine 11 via a conduit 13, and a liquefaction device 14B that liquefies the carbon dioxide recovered by the recovery device 14A by compression. The ship 10 includes a temporary storage tank 16 that temporarily stores liquefied carbon dioxide, and a plurality of ballast tanks 18T1 to 18T3 arranged in a row along the traveling direction of the ship 10 as storage tanks for storing the liquefied carbon dioxide temporarily stored in the temporary storage tank 16. The recovery device 14A may be a filter, specifically, a device using a carbon dioxide separation membrane, or a device using an adsorbent for carbon dioxide. Each of the recovery device 14A, the liquefaction device 14B, and the ballast tanks 18T1 to 18T3 is an example of the "recovery section", "liquefaction section", and "storage tank" of the technology of the present disclosure.

[0013] Each of the ballast tanks 18T1 to 18T3 stores ballast water (i.e., seawater) for adjusting the draft and inclination of the hull 12. The other end of a pipe (not shown) whose one end is located outside the hull 12 (i.e., at sea) is connected to each of the ballast tanks 18T1 to 18T3. A valve (not shown) is provided in each pipe. For example, when the valve provided in the pipe connected to the first ballast tank 18T1 is opened, the ballast water stored in the first ballast tank 18T1 is discharged outside the hull 12. Each of the temporary storage tank 16 and the ballast tanks 18T1 to 18T3 has a CE (cryogenic liquefied gas storage tank, i.e., Cold Evaporator) function. Specifically, each of the temporary storage tank 16 and the ballast tanks 18T1 to 18T3 is composed of a double-walled tank, and is also a vacuum-insulated tank, and is equipped with a pressurized evaporator. Therefore, each of the temporary storage tank 16 and the ballast tanks 18T1 to 18T3 safely stores low-temperature liquefied carbon dioxide, and uses a pressurized evaporator to maintain the liquefied carbon dioxide at a constant pressure.

[0014] The engine 11 and the ballast tanks 18T1 to 18T3 are provided inside the hull 12, and the recovery device 14A, the liquefaction device 14B, and the temporary storage tank 16 are provided on the hull 12. The recovery device 14A, the liquefaction device 14B, and the temporary storage tank 16 may be provided inside the hull 12.

[0015] The liquefaction device 14B liquefies the supplied carbon dioxide. The liquefaction device 14B supplies the liquefied carbon dioxide to the temporary storage tank 16 via the pipe 15. Each of the temporary storage tank 16 and the ballast tanks 18T1 to 18T3 is connected via the pipes 17L1 to 17L3. Valves (not shown) are provided in each of the pipes 17L1 to 17L3. Therefore, for example, when the valve provided in the pipe 17L1 is opened, the liquefied carbon dioxide stored in the temporary storage tank 16 is supplied to the first ballast tank 18T1.

[0016] The capacity of the temporary storage tank 16 is the same as the capacity of each of the ballast tanks 18T1 to 18T3.

[0017] Next, the operation of the present embodiment will be described.

[0018] FIG. 2 is a diagram showing an example of the storage states of the temporary storage tank 16 and the three ballast tanks 18T1 to 18T3 at the start of operation of the ship 10 according to the first embodiment. As shown in FIG. 2, at the start of operation of the ship 10, the temporary storage tank 16 is empty, while each of the three ballast tanks 18T1 to 18T3 is filled with ballast water up to its maximum capacity.

[0019] FIG. 3 is a diagram showing an example of the storage state of the temporary storage tank 16 storing liquefied carbon dioxide recovered from the exhaust gas from the operating engine 11 and the storage states of the three ballast tanks 18T1 to 18T3 after the start of operation of the ship 10 according to the present embodiment. FIG. 4 is a diagram showing an example of the storage states of the temporary storage tank 16 and the three ballast tanks 18T1 to 18T3 after the ballast water has been discharged from the first ballast tank 18T1 among the three ballast tanks 18T1 to 18T3.

[0020] When the operation of the ship 10 starts, specifically, when the engine 11 starts operating, the engine 11 discharges gas. The exhaust gas from the engine 11 is led to the recovery device 14A via the conduit 13. The recovery device 14A recovers carbon dioxide from the exhaust gas. The recovery device 14A supplies the recovered carbon dioxide to the liquefaction device 14B. The liquefaction device 14B liquefies the carbon dioxide supplied by the recovery device 14A. The liquefaction device 14B supplies the liquefied carbon dioxide to the temporary storage tank 16. Therefore, the temporary storage tank 16 stores the liquefied carbon dioxide. Each of the three ballast tanks 18T1 to 18T3 is maintained in a state where the ballast water is filled up to its maximum capacity.

[0021] As shown in FIG. 3, when the temporary storage tank 16 stores liquefied carbon dioxide at its maximum capacity and, for example, a liquid level sensor (not shown) detects this, a computer (not shown) to which a signal is input from the liquid level sensor opens a valve provided in a pipe connected to the first ballast tank 18T1. When the valve opens, the ballast water stored in the first ballast tank 18T1 is discharged outside the hull 12. As shown in FIG. 4, all of the ballast water stored in the first ballast tank 18T1 is discharged outside the hull 12. That is, the first ballast tank 18T1 becomes empty.

[0022] When a liquid level sensor (not shown) detects that the first ballast tank 18T1 has become empty, a computer (not shown) to which a signal is input from the liquid level sensor opens a valve provided in the pipe 17L1. When the valve opens, the temporary storage tank 16 supplies liquefied carbon dioxide to the first ballast tank 18T1.

[0023] FIG. 5 is a diagram showing an example of the storage states of the temporary storage tank 16 and the three ballast tanks 18T1 to 18T3 after the liquefied carbon dioxide stored in the temporary storage tank 16 has been stored in the first ballast tank 18T1.

[0024] As described above, the capacity of the temporary storage tank 16 is the same as the capacity of each of the ballast tanks 18T1 to 18T3. Therefore, when all of the liquefied carbon dioxide stored at the maximum capacity in the temporary storage tank 16 is supplied to the first ballast tank 18T1 as shown in FIG. 5, the first ballast tank 18T1 stores liquefied carbon dioxide at its maximum capacity.

[0025] In this way, the first ballast tank 18T1 stores the liquefied carbon dioxide obtained by liquefying the carbon dioxide discharged by the engine 11 instead of the ballast water, so that the hull 12 is maintained horizontally. Therefore, the stored liquefied carbon dioxide is used to maintain the hull 12 horizontally. Accordingly, the first ballast tank 18T1 is used to store liquefied carbon dioxide and to maintain the hull 12 horizontally.

[0026] FIG. 6 is a diagram showing an example of a state in which the liquefied carbon dioxide is stored in the temporary storage tank 16 and a storage state of the three ballast tanks 18T1 to 18T3 after the ballast water is discharged from the second ballast tank 18T2 among the three ballast tanks 18T1 to 18T3.

[0027] The operation of the ship 10 continues, and the recovery device 14A supplies the carbon dioxide discharged from the engine 11 to the liquefaction device 14B. The liquefaction device 14B liquefies the supplied liquefied carbon dioxide and supplies the liquefied carbon dioxide to the temporary storage tank 16. The temporary storage tank 16 stores the liquefied carbon dioxide up to the maximum capacity.

[0028] When, for example, a liquid level sensor (not shown) detects that the temporary storage tank 16 stores liquefied carbon dioxide at the maximum capacity as shown in FIG. 6, a computer (not shown) into which a signal is input from the liquid level sensor opens a valve provided in a pipe connected to the second ballast tank 18T2. When the valve opens, the ballast water stored in the second ballast tank 18T2 is discharged outside the hull 12. As shown in FIG. 6, all of the ballast water stored in the second ballast tank 18T2 is discharged outside the hull 12. That is, the second ballast tank 18T2 becomes empty.

[0029] FIG. 7 is a diagram showing an example of a storage state of the temporary storage tank 16 and the three ballast tanks 18T1 to 18T3 after the liquefied carbon dioxide stored in the temporary storage tank 16 is stored in the second ballast tank 18T2.

[0030] When a liquid level sensor (not shown) detects that the second ballast tank 18T2 has become empty, a computer (not shown) into which a signal is input from the liquid level sensor opens a valve provided in the pipe 17L2. When the valve opens, the temporary storage tank 16 supplies liquefied carbon dioxide to the second ballast tank 18T2.

[0031] In this way, the second ballast tank 18T2 stores the liquefied carbon dioxide in which the carbon dioxide discharged from the engine 11 is liquefied, instead of the ballast water, so that the hull 12 is maintained horizontally. Therefore, the stored liquefied carbon dioxide is used to maintain the hull 12 horizontally. Accordingly, the second ballast tank 18T2 is used to store the liquefied carbon dioxide and to maintain the hull 12 horizontally.

[0032] The operation of the ship 10 continues further, and the recovery device 14A supplies the carbon dioxide recovered from the exhaust gas to the liquefaction device 14B. The liquefaction device 14B liquefies the supplied liquefied carbon dioxide and supplies the liquefied carbon dioxide to the temporary storage tank 16. The temporary storage tank 16 stores the liquefied carbon dioxide up to its maximum capacity.

[0033] When, for example, a liquid level sensor (not shown) detects that the temporary storage tank 16 stores liquefied carbon dioxide up to its maximum capacity, a computer (not shown) into which a signal is input from the liquid level sensor opens a valve provided in a pipe connected to the third ballast tank 18T3. When the valve opens, the ballast water stored in the third ballast tank 18T3 is discharged outside the hull 12. All of the ballast water stored in the third ballast tank 18T3 is discharged outside the hull 12. That is, the third ballast tank 18T3 becomes empty.

[0034] When a liquid level sensor (not shown) detects that the third ballast tank 18T3 has become empty, a computer (not shown) into which a signal is input from the liquid level sensor opens a valve provided in the pipe 17L3. When the valve opens, the temporary storage tank 16 supplies liquefied carbon dioxide to the third ballast tank 18T3.

[0035] Thus, the third ballast tank 18T3 stores the liquefied carbon dioxide in which the carbon dioxide discharged from the engine 11 is liquefied, instead of the ballast water, so that the hull 12 is maintained horizontally. Therefore, the stored liquefied carbon dioxide is utilized to maintain the hull 12 horizontally. Accordingly, the third ballast tank 18T3 is utilized to store the liquefied carbon dioxide and to maintain the hull 12 horizontally.

[0036] As described above, in the present embodiment, each of the ballast tanks 18T1 to 18T3 stores the liquefied carbon dioxide in which the carbon dioxide discharged from the engine 11 is liquefied, instead of the ballast water. Each of the ballast tanks 18T1 to 18T3 maintains the hull 12 horizontally by storing the liquefied carbon dioxide.

[0037] Thus, the present embodiment maintains the hull 12 horizontally through the ballast tanks 18T1 to 18T3 by using the liquefied carbon dioxide in which the carbon dioxide discharged from the engine 11 is liquefied. Therefore, the present embodiment can reduce the dead space generated for storing the carbon dioxide recovered from the exhaust gas of the engine, as compared with the prior art.

[0038] FIG. 8 is a diagram showing an example of a state in which the ballast tanks 18T1 to 18T3 for storing carbon dioxide are placed on a vehicle by a moving mechanism when the ship 10 of the first embodiment is discharging its cargo.

[0039] Incidentally, the ballast tanks 18T1 to 18T3 of the present embodiment are of a cartridge type that can be removed from the hull 12. Therefore, when the ship 10 is discharging its cargo, the ballast tanks 18T1 to 18T3 are removed from the hull 12, and a moving mechanism (not shown) moves the removed ballast tanks 18T1 to 18T3 to land transportation means such as a vehicle. The land transportation means transports the liquefied carbon dioxide to a predetermined transportation destination by transporting the ballast tanks 18T1 to 18T3. Therefore, the present embodiment can efficiently transport liquefied carbon dioxide to a predetermined transportation destination. Examples of the transportation destination include a carbon dioxide utilization industrial site or a CCS (Carbon dioxide Capture and Storage) site.

[0040] As for the carbon dioxide utilization industrial site, firstly, there is a site that directly uses carbon dioxide, and secondly, there is a site that indirectly uses carbon dioxide. The first site that directly uses carbon dioxide is, for example, a site that uses carbon dioxide as an industrial gas for shield gas for welding or in the beverage and food fields such as carbonated water, in the medical field, or as dry ice for cold storage and transportation of fresh food. The second site that indirectly uses carbon dioxide is a site that converts carbon dioxide into methane, methanol, ethanol, etc. and uses it as a fuel or chemical, or converts carbon dioxide into calcium carbonate and uses it as a raw material for cement.

[0041] The CCS site is a site where carbon dioxide is stored deep underground.

[0042] The ballast tanks 18T1 to 18T3 from which carbon dioxide has been discharged and become empty at the above site are transported to the ship 10 by the above vehicle and are installed on the hull 12 again.

[0043] [Second Embodiment] Next, the second embodiment will be described. Since the configuration of the ship 100 of the second embodiment is substantially the same as the configuration of the ship 10 of the first embodiment, the different parts will be described.

[0044] FIG. 9 is a schematic top view of an example of the interior of a ship 10 according to the second embodiment.

[0045] In the first embodiment, the three ballast tanks 18T1 to 18T3 are arranged in a single row along the traveling direction of the ship 10. In contrast, in the second embodiment, 2n ballast tanks 18TL1 to 18Ln and 18TR1 to 18Rn are arranged in multiple rows along the traveling direction of the ship 10. Specifically, for example, the ballast tanks 18TL1 to 18Ln and 18TR1 to 18Rn are arranged in two rows, one row on the left and one row on the right. The ballast tanks 18TL1 to 18Ln are arranged in the left row, and the ballast tanks 18TR1 to 18Rn are arranged in the right row. Note that the number of rows is not limited to two, and may be three, four, or the like.

[0046] The ship 100 according to the second embodiment includes a temporary storage tank 160 having a capacity, for example, twice as large as the capacity of each of the ballast tanks 18TL1 to 18Ln and 18TR1 to 18Rn.

[0047] Next, the operation of the second embodiment will be described.

[0048] FIG. 10 is a diagram showing an example of the storage state of the temporary storage tank 160 and the 2n ballast tanks 18L1 to 18Ln and 18R1 to 18Rn at the start of operation of the ship 100 according to the second embodiment. As shown in FIG. 10, at the start of operation of the ship 10, the temporary storage tank 160 is empty, while each of the 2n ballast tanks 18TL1 to 18Ln and 18TR1 to 18Rn is filled with ballast water at the maximum capacity.

[0049] FIG. 11 is a diagram showing an example of the storage states of the temporary storage tank 160 and the 2n ballast tanks 18TL1 to 18Ln and 18TR1 to 18Rn when carbon dioxide is recovered from the exhaust gas from the operating engine 11 after the start of operation of the ship 100 in the second embodiment, and the liquefied liquefied carbon dioxide is stored in the temporary storage tank 160 while the ballast water is being discharged from each of the first ballast tank 18L1 in the left row and the nth ballast tank 18Rn in the right row.

[0050] As shown in FIG. 11, after the start of operation of the ship 100, the recovery device 14A recovers carbon dioxide from the exhaust gas, the liquefaction device 14B liquefies the carbon dioxide supplied by the recovery device 14A, and the temporary storage tank 160 stores the liquefied carbon dioxide. Ballast water is discharged from each of the first ballast tank 18L1 located at the tip of the left row and the nth ballast tank 18Rn located at the rear end of the right row.

[0051] FIG. 12 is a diagram showing an example of the storage states of the temporary storage tank 16 and the 2n ballast tanks 18T1 to 18T3 when carbon dioxide is recovered from the exhaust gas after the start of operation of the ship 100 in the second embodiment, the temporary storage tank 160 stores the liquefied carbon dioxide at the maximum capacity, and all the ballast water has been discharged from each of the first ballast tank 18L1 in the left row and the nth ballast tank 18Rn in the right row.

[0052] As shown in FIG. 12, in this embodiment, at the timing when the temporary storage tank 160 stores the liquefied carbon dioxide at the maximum capacity, all the ballast water is discharged from each of the first ballast tank 18L1 in the left row and the nth ballast tank 18Rn in the right row, and each of the ballast tank 18L1 and the ballast tank 18Rn becomes empty.

[0053] Note that the timing when each of the ballast tank 18L1 and the ballast tank 18Rn becomes empty may be before the timing when the temporary storage tank 160 stores the liquefied carbon dioxide at the maximum capacity.

[0054] FIG. 13 is a diagram showing an example of the storage states of the temporary storage tank 160 and the 2n ballast tanks 18T1 to 18T3 when the liquefied carbon dioxide stored in the temporary storage tank 160 is stored in each of the first ballast tank 18L1 in the left row and the n-th ballast tank 18Rn in the right row.

[0055] As shown in FIG. 13, the liquefied carbon dioxide stored in the temporary storage tank 160 is supplied to and stored in each of the first ballast tank 18L1 in the left row and the n-th ballast tank 18Rn in the right row.

[0056] Since each of the first ballast tank 18L1 and the n-th ballast tank 18Rn in the right row stores the liquefied carbon dioxide obtained by liquefying the carbon dioxide discharged from the engine 11 instead of the ballast water, the hull 12 is maintained horizontally.

[0057] Regarding the other ballast tanks as well, in the same manner as above, the discharge of the ballast water and the storage of the liquefied carbon dioxide are performed. For example, regarding the second ballast tank 28L1 in the left row and the (n - 1)-th ballast tank 28Rn - 1 in the right row, the discharge of the ballast water and the storage of the liquefied carbon dioxide are performed. Next, regarding the third ballast tank in the left row and the (n - 2)-th ballast tank 2 in the right row, the discharge of the ballast water and the storage of the liquefied carbon dioxide are performed,... Regarding the n-th ballast tank 18Ln at the rear end in the left row and the first ballast tank 18R1 at the front end in the right row, the discharge of the ballast water and the storage of the liquefied carbon dioxide are performed.

[0058] In the second embodiment, the dead space generated for storing the carbon dioxide recovered from the exhaust gas of the engine can be made smaller than in the prior art.

[0059] In the first embodiment and the second embodiment, all of the plurality of ballast tanks provided in the ship are used as tanks for storing liquefied carbon dioxide, but only some of the plurality of ballast tanks may be used as tanks for storing liquefied carbon dioxide.

[0060] The ships of the first and second embodiments may be LNG carriers that transport liquefied natural gas (LNG). The ships of the first and second embodiments may also be liquefied carbon dioxide carriers that transport stored liquefied carbon dioxide. The destination for delivery is, as described above, a carbon dioxide utilization industrial site or a CCS site. In order to obtain synthetic fuels such as methanol, the carbon dioxide stored as described above may be supplied to an onshore synthetic fuel production facility. The synthetic fuel can be reused as fuel for an LNG fuel ship or a methanol dual-fuel ship, etc. Therefore, zero emissions or carbon dioxide emission reduction of the ship becomes possible.

Explanation of Reference Numerals

[0061] 10 Ship 11 Engine 13 Conduit 14A Recovery Device 14B Liquefaction Device 16 Temporary Storage Tank 18T1~18T3 Storage Tank 100 Ship 160 Temporary Storage Tank 18L1~18Ln, 18R1~18Rn Storage Tank

Claims

1. An engine that discharges a gas containing carbon dioxide when operating, a recovery unit that recovers the carbon dioxide from the gas discharged from the engine, a liquefaction unit that liquefies the recovered carbon dioxide, a storage tank that stores liquefied carbon dioxide, and the storage tank is a ballast tank, a ship.

2. further comprising a temporary storage tank that temporarily stores liquefied carbon dioxide, the storage tank stores the liquefied carbon dioxide temporarily stored in the temporary storage tank, the ship according to claim 1.

3. The ship according to claim 2, wherein the capacity of the temporary storage tank is the same as the capacity of the ballast tank.

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