Ship, method for adjusting pressure of tank in ship

Abstract

To provide a ship and a pressure adjusting method of a tank in a ship capable of smoothly performing a tank operation while suppressing the generation of dry ice.SOLUTION: A ship comprises a hull, a tank 10 provided in the hull and storing liquified carbon dioxide, and a carbon dioxide injection part 20 which is provided in the hull, and which can inject a higher-temperature and higher-pressure carbon dioxide gas than the carbon dioxide in the tank 10 into the tank 10.SELECTED DRAWING: Figure 2

Description

Technical Field

[0001] The present disclosure relates to a ship and a method for adjusting the pressure of a tank in a ship.

Background Art

[0002] Patent Document 1 discloses a configuration for transporting dry ice deposited by spraying liquid carbon dioxide in a ship's hold.

[0003] Also, Patent Document 2 discloses that carbon dioxide is transported in a state of compressed carbon dioxide gas at normal temperature (for example, 0 to 30°C) under a tank pressure of 15 kg / cm 2 of.

Prior Art Documents

Patent Documents

[0004]

Patent Document 1

Patent Document 2

Summary of the Invention

Problems to be Solved by the Invention

[0005] By the way, when liquefied carbon dioxide is stored in a tank provided in a hull, the liquefied carbon dioxide may solidify to form dry ice for the following reasons. That is, the pressure of the liquefied carbon dioxide in the tank becomes the one corresponding to the tank operating pressure. The triple point pressure at which the gas phase, liquid phase, and solid phase of liquefied carbon dioxide coexist is higher than the triple point pressures of liquefied gas (LNG: Liquefied Natural Gas) and liquefied petroleum gas (LPG: Liquefied Petroleum Gas), and there is a possibility of reaching the triple point when the tank is depressurized during operation.

[0006] When the pressure of liquefied carbon dioxide becomes equal to or lower than the triple point pressure, flash evaporation of the liquefied carbon dioxide may occur. Then, due to the latent heat of evaporation of the flash evaporation of the liquefied carbon dioxide, the temperature of the liquefied carbon dioxide remaining without evaporation may decrease, and there is a possibility that the liquefied carbon dioxide solidifies in the tank to generate dry ice. Therefore, the tank operating pressure (the design pressure of the tank) is set so that the pressure of the liquefied carbon dioxide does not become equal to or lower than the triple point pressure. However, if the tank operating pressure is set significantly higher than the triple point pressure of liquefied carbon dioxide, the tank itself and the piping connected to the tank must have a pressure-resistant structure according to the tank operating pressure (the design pressure of the tank), leading to an increase in cost.

[0007] Also, for example, when the liquefied carbon dioxide in the tank sways with the rocking of the hull, the dynamic pressure of the liquefied carbon dioxide increases according to the flow velocity of the liquefied carbon dioxide, and the static pressure of the liquefied carbon dioxide decreases. Due to the decrease in the static pressure of the liquefied carbon dioxide in the tank caused in this way, there is a possibility that the liquefied carbon dioxide solidifies in the tank to generate dry ice. And since the density of dry ice is greater than that of liquefied carbon dioxide, if dry ice is generated in the tank, it will sink and accumulate at the bottom of the tank. Therefore, even after the pressure in the tank recovers, it may take time for the dry ice to sublime.

[0008] The present disclosure has been made to solve the above problems, and an object thereof is to provide a ship capable of suppressing the generation of dry ice and smoothly operating a tank, and a method for adjusting the pressure of the tank in the ship.

Means for Solving the Problems

[0009] To solve the above problems, a ship according to the present disclosure includes a hull, a tank, a high-temperature and high-pressure gas tank, and a carbon dioxide injection unit. The tank is provided in the hull. The tank stores liquefied carbon dioxide. The high-temperature and high-pressure gas tank is provided in the hull. The high-temperature and high-pressure gas tank can store carbon dioxide gas at a temperature and pressure higher than those of the carbon dioxide in the tank. The carbon dioxide injection unit can inject the high-temperature and high-pressure carbon dioxide gas stored in the high-temperature and high-pressure gas tank into the tank. When the fluctuation of the liquefied carbon dioxide stored in the tank reaches a predetermined level, the carbon dioxide injection unit injects the carbon dioxide gas into the tank.

[0010] A method for adjusting the pressure of a tank in a ship according to the present disclosure is a method for adjusting the pressure of a tank in a ship as described above, and includes a step of acquiring information and a step of injecting carbon dioxide gas into the tank. In the step of acquiring information, at least one of information regarding the pressure in the tank and information regarding the sway of the liquefied carbon dioxide stored in the tank is acquired. In the step of injecting carbon dioxide gas into the tank, based on the acquired information, the carbon dioxide injection unit injects the carbon dioxide gas into the tank.

Effects of the Invention

[0011] According to the ship and the method for adjusting the pressure of a tank in a ship of the present disclosure, the generation of dry ice can be suppressed, and the operation of the tank can be smoothly performed.

Brief Description of the Drawings

[0012]

Figure 1

Figure 2

Figure 3

Figure 4

Figure 5

Embodiments for Carrying Out the Invention

[0013] Hereinafter, a ship according to an embodiment of the present disclosure will be described with reference to the drawings. (Overall Configuration of the Ship) FIG. 1 is a plan view showing a schematic configuration of a ship according to an embodiment of the present disclosure. FIG. 2 is a diagram showing a schematic configuration of a carbon dioxide injection unit according to an embodiment of the present disclosure. As shown in FIGS. 1 and 2, the ship 1 of this embodiment mainly includes a hull 2, a tank 10, and a carbon dioxide injection unit 20. The ship 1 transports liquefied carbon dioxide.

[0014] As shown in FIG. 1, the hull 2 has a pair of side hulls 3A and 3B forming its outer shell, and a bottom (not shown). The side hulls 3A and 3B include a pair of side shell plates forming the left and right side hulls respectively. The bottom (not shown) includes a bottom shell plate connecting these side hulls 3A and 3B. Due to these pair of side hulls 3A and 3B and the bottom (not shown), the outer shell of the hull 2 forms a U shape in a cross section orthogonal to the fore-and-aft direction FA of the ship.

[0015] The hull 2 further includes a upper deck 5 which is an all-through deck arranged at the uppermost layer. An upper structure 7 is formed on this upper deck 5. Living quarters and the like are provided inside the upper structure 7. In the ship 1 of this embodiment, for example, a cargo space 8 for loading cargo is provided on the bow 2a side in the fore-and-aft direction FA rather than the upper structure 7.

[0016] (Configuration of the Tank) The tank 10 is provided in the hull 2. A plurality of tanks 10 are arranged in the cargo space 8 along the fore-and-aft direction FA. In the embodiment of the present disclosure, two tanks 10 are arranged at intervals in the fore-and-aft direction FA. As shown in FIG. 2, the tank 10 stores liquefied carbon dioxide L therein. The pressure in the tank 10 is, for example, about 0.55 to 2.0 MPaG. The temperature of the liquefied carbon dioxide L stored in the tank 10 is, for example, about -50 to -20°C.

[0017] The tank 10 has, for example, a cylindrical shape extending in the horizontal direction. The tank 10 includes a cylindrical portion 12 and end spherical portions 13. The cylindrical portion 12 extends with the horizontal direction as the longitudinal direction. In the present embodiment, the cylindrical portion 12 is formed in a cylindrical shape with a circular cross-sectional shape perpendicular to the longitudinal direction. The end spherical portions 13 are respectively arranged at both longitudinal ends of the cylindrical portion 12. Each end spherical portion 13 is hemispherical and closes the openings at both longitudinal ends of the cylindrical portion 12. Note that the tank 10 is not limited to a cylindrical shape, and the tank 10 may be spherical, square, or the like.

[0018] (Configuration of Carbon Dioxide Injection Section) As shown in FIG. 2, the carbon dioxide injection section 20 is configured to be able to inject carbon dioxide gas G that is at a higher temperature and higher pressure than the carbon dioxide (liquid phase 10a and gas phase 10b) in the tank 10 into the tank 10. The carbon dioxide injection section 20 is provided in the hull 2. The carbon dioxide injection section 20 includes a gas tank 21, a first injection pipe 22, a second injection pipe 23, a pressure sensor 24, an acceleration sensor 25, and a control device 60.

[0019] The gas tank 21 stores carbon dioxide gas G. The pressure of the carbon dioxide gas G stored in the gas tank 21 is, for example, 5 to 15.7 MPaG. The temperature of the carbon dioxide gas G stored in the gas tank 21 is room temperature, for example, about 15 to 45 °C. Since the gas tank 21 stores carbon dioxide gas G at room temperature, it does not necessarily need to have a heat insulation specification. The gas tank 21 may be provided in the cargo space 8, or may be provided at an appropriate other location such as on the upper deck 5.

[0020] The first injection pipe 22 and the second injection pipe 23 each form a flow path for injecting the carbon dioxide gas G in the gas tank 21 into the tank 10. The base end portion of the first injection pipe 22 and the base end portion of the second injection pipe 23 are each connected to the gas tank 21. The tip portion 22s of the first injection pipe 22 opens into the gas phase 10b in the upper part of the tank 10. The tip portion 23s of the second injection pipe 23 opens into the liquid phase 10a (liquefied carbon dioxide L) at the bottom of the tank 10.

[0021] The first injection pipe 22 is provided with an on-off valve 22v, and the second injection pipe 23 is provided with an on-off valve 23v. By opening and closing the on-off valve 22v, the injection of the carbon dioxide gas G into the tank 10 by the first injection pipe 22 is interrupted, and by opening and closing the on-off valve 23v, the injection of the carbon dioxide gas G into the tank 10 by the second injection pipe 23 is interrupted. In this embodiment, the opening and closing operations of the on-off valves 22v and 23v are automatically controlled by the control device 60. Note that the opening and closing operations of the on-off valves 22v and 23v may be manually performed by an operator, for example.

[0022] The pressure sensor 24 acquires information regarding the pressure in the tank 10. More specifically, the pressure sensor 24 detects the pressure of the gas phase 10b in the tank 10. The pressure sensor 24 outputs the detected pressure data toward the control device 60.

[0023] The acceleration sensor 25 acquires information regarding the sloshing of the liquid phase 10a within the tank 10. In this embodiment, the acceleration sensor 25 detects the acceleration caused by the swaying of the hull 2 as information regarding the sloshing of the liquid phase 10a within the tank 10. The acceleration sensor 25 detects, for example, the acceleration caused by the pitching of the hull 2 in the fore-and-aft direction FA and the rolling of the hull 2 in the beam direction. The acceleration sensor 25 may be provided at multiple locations on the hull 2. The acceleration sensor 25 outputs the detected acceleration data towards the control device 60.

[0024] (Hardware Configuration Diagram) As shown in FIG. 3, the control device 60 is a computer including a CPU 61 (Central Processing Unit), a ROM 62 (Read Only Memory), a RAM 63 (Random Access Memory), an HDD 64 (Hard Disk Drive), and a signal reception module 65. The signal reception module 65 receives the detection signals from the pressure sensor 24 and the acceleration sensor 25.

[0025] (Functional Block Diagram) As shown in FIG. 4, the CPU 61 of the control device 60 realizes each functional configuration of the signal input unit 70, the determination unit 71, the opening / closing control unit 72, and the output unit 75 by executing programs stored in advance in the HDD 64, the ROM 62, etc. The signal input unit 70 receives, via the signal reception module 65, the detection signals from the pressure sensor 24 and the acceleration sensor 25, that is, the data of the detected value of the pressure of the gas phase 10b within the tank 10 and the data of the detected value of the acceleration caused by the swaying of the hull 2.

[0026] The determination unit 71 determines the necessity of injecting the carbon dioxide gas G from the gas tank 21 into the tank 10 based on the detection signals from the pressure sensor 24 and the acceleration sensor 25 received by the signal input unit 70. The opening / closing control unit 72 controls the opening and closing of the on-off valve 22v and the opening and closing of the on-off valve 23v based on the determination result of the necessity of injecting the carbon dioxide gas G in the determination unit 71. The opening / closing control unit 72 sends a control signal for opening and closing the on-off valves 22v and 23v to the output unit 75. The output unit 75 outputs the control signal sent from the opening / closing control unit 72 to the on-off valve 22v and the on-off valve 23v.

[0027] (Procedure of the tank pressure adjustment method) As shown in FIG. 5, the pressure adjustment method S1 of the tank 10 according to the embodiment of the present disclosure includes a step S2 of acquiring information, a step S3 of determining the necessity of injection, a step S4 of injecting carbon dioxide gas into the tank, and a step S5 of stopping the injection of carbon dioxide gas.

[0028] In the step S2 of acquiring information, the control device 60 acquires detection signals from the pressure sensor 24 and the acceleration sensor 25. The detection signals from the pressure sensor 24 and the acceleration sensor 25 are received by the signal input unit 70. The control device 60 acquires, from the pressure sensor 24, a detected value of the pressure of the gas phase 10b in the tank 10 as information on the pressure in the tank 10. The control device 60 acquires, from the acceleration sensor 25, a detected value of the acceleration due to the sway of the hull 2 as information on the sway of the liquefied carbon dioxide L stored in the tank 10.

[0029] In the step S3 of determining the necessity of injection, the control device 60 determines the necessity of injecting the carbon dioxide gas G from the gas tank 21 into the tank 10 by the determination unit 71. In this determination unit 71, the necessity of injecting the carbon dioxide gas G is determined based on at least one of the information on the pressure in the tank 10 acquired in the step S2 and the information on the sway of the liquefied carbon dioxide L stored in the tank 10.

[0030] In the determination unit 71, for example, when the pressure in the tank 10 becomes equal to or lower than a predetermined lower pressure limit value, it is determined that it is necessary to inject carbon dioxide gas G into the tank 10. The predetermined lower pressure limit value is set to be equal to or higher than the triple point pressure of the liquefied carbon dioxide L. Further, the determination unit 71 determines that, for example, when the acceleration generated in the hull 2 becomes equal to or higher than a predetermined threshold value, it is necessary to inject carbon dioxide gas G into the tank 10.

[0031] Here, the state where the acceleration generated in the hull 2 becomes equal to or higher than a predetermined threshold value means a state where the shaking of the liquefied carbon dioxide L stored in the tank 10 becomes equal to or higher than a predetermined level. In a state where the shaking of the liquefied carbon dioxide L stored in the tank 10 is equal to or higher than a predetermined level in this way, a decrease in the static pressure in the tank occurs due to the shaking of the liquefied carbon dioxide L stored in the tank 10, and the liquefied carbon dioxide L in the tank may solidify. In other words, for example, when the acceleration generated in the hull 2 is smaller than a predetermined threshold value, substantially no solidification of the liquefied carbon dioxide L due to the shaking of the liquefied carbon dioxide L stored in the tank 10 occurs.

[0032] That is, the determination unit 71 determines that, for example, even if the pressure in the tank 10 is not equal to or lower than the lower pressure limit value, when the acceleration generated in the hull 2 becomes equal to or higher than the threshold value, it is necessary to inject carbon dioxide gas G into the tank 10. And the determination unit 71 determines that even if the acceleration generated in the hull 2 is not equal to or higher than the threshold value, if the pressure in the tank 10 is equal to or lower than the lower pressure limit value, it is necessary to inject carbon dioxide gas G into the tank 10. Note that the determination unit 71 may be configured to determine that it is necessary to inject carbon dioxide gas G into the tank 10 when the pressure in the tank 10 is equal to or lower than the lower pressure limit value and the acceleration generated in the hull 2 is equal to or higher than the threshold value. Further, the determination unit 71 may determine the necessity of injecting carbon dioxide gas G based on a map, table, mathematical formula, etc. preset based on the correlation between the pressure in the tank 10 and the acceleration generated in the hull 2.

[0033] If, as a result of the determination in step S3, it is determined that it is not necessary to inject carbon dioxide gas G into tank 10 ( "No" in FIG. 5), the process returns to step S2 described above. On the other hand, if, as a result of the determination in step S3, it is determined that it is necessary to inject carbon dioxide gas G into tank 10 ( "Yes" in FIG. 5), the process returns to step S4 of injecting carbon dioxide gas into the tank.

[0034] In step S4 of injecting carbon dioxide gas into the tank, carbon dioxide gas G is injected from gas tank 21 into tank 10. For this, the opening / closing control unit 72 outputs a control signal for opening the opening / closing valves 22v and 23v to the opening / closing valves 22v and 23v via the output unit 75.

[0035] Here, the opening / closing control unit 72 may open both the opening / closing valves 22v and 23v and inject carbon dioxide gas G from gas tank 21 into tank 10 through both the first injection pipe 22 and the second injection pipe 23. Further, the opening / closing control unit 72 may open only the opening / closing valve 22v and inject carbon dioxide gas G from gas tank 21 into the gas phase 10b of tank 10 through only the first injection pipe 22. The opening / closing control unit 72 may further open only the opening / closing valve 23v and inject carbon dioxide gas G from gas tank 21 into the liquid phase 10a at the bottom of tank 10 through only the second injection pipe 23.

[0036] When carbon dioxide gas G is injected into tank 10, since carbon dioxide gas G is at a higher temperature and pressure than the carbon dioxide in tank 10 (including both the liquid phase 10a and the gas phase 10b), the temperature and pressure in tank 10 increase. If dry ice D was generated in tank 10, the dry ice D sublimes as the temperature and pressure in tank 10 increase.

[0037] In step S5 of stopping the injection of carbon dioxide gas, when the preset injection end condition is satisfied, the injection of carbon dioxide gas G from the gas tank 21 into the tank 10 is stopped. For example, when the pressure in the tank 10 detected by the pressure sensor 24 exceeds the lower pressure limit value or exceeds a set value set to be equal to or higher than the lower pressure limit value, the control device 60 stops the injection of carbon dioxide gas G. When stopping the injection of carbon dioxide gas G, the opening / closing control unit 72 outputs a control signal for closing the on-off valves 22v and 23v to the on-off valves 22v and 23v via the output unit 75. When the on-off valves 22v and 23v are in the closed state, the injection of carbon dioxide gas G from the gas tank 21 into the tank 10 stops. When the injection of carbon dioxide gas G by the above step S5 stops, the process returns to the above step S2, and the above-described series of processes are repeated.

[0038] (Function and effect) The ship 1 of the above embodiment includes a hull 2, a tank 10 provided in the hull 2 for storing liquefied carbon dioxide L, and a carbon dioxide injection unit 20 provided in the hull 2 for injecting carbon dioxide gas G that is at a higher temperature and pressure than the carbon dioxide (liquid phase 10a and gas phase 10b) in the tank 10 into the tank 10.

[0039] According to such a ship 1, when a state occurs in which dry ice D is generated in the liquefied carbon dioxide L stored in the tank 10, the carbon dioxide injection unit 20 can inject carbon dioxide gas G into the tank 10. And since the carbon dioxide gas G is at a higher temperature and pressure than the carbon dioxide (including both the liquid phase 10a and the gas phase 10b) in the tank 10, a decrease in the pressure in the tank 10 can be suppressed. Also, when dry ice D has been generated in the tank 10, the dry ice D can be sublimated by the carbon dioxide gas G. Therefore, it is possible to suppress the generation of dry ice D and smoothly operate the tank 10.

[0040] In the ship 1 of the above embodiment, furthermore, the carbon dioxide injection unit 20 is configured to be able to inject carbon dioxide gas G into the gas phase 10b of the carbon dioxide in the tank 10. Therefore, by injecting the carbon dioxide gas G into the gas phase 10b of the carbon dioxide in the tank 10 with the carbon dioxide injection section 20, the pressure in the tank 10 can be immediately increased.

[0041] In the ship 1 of the above embodiment, furthermore, the carbon dioxide injection section 20 is configured to be able to inject the carbon dioxide gas G into the liquid phase 10a of the carbon dioxide in the tank 10. Therefore, by injecting the carbon dioxide gas G into the liquid phase 10a of the carbon dioxide in the tank 10 with the carbon dioxide injection section 20, when dry ice D is generated in the liquid phase 10a of the carbon dioxide, the carbon dioxide gas G can be sent around the dry ice D. Then, the liquid phase 10a of the carbon dioxide around the dry ice D is gasified by the injected carbon dioxide gas G, so that the pressure in the tank 10 can be increased and the sublimation of the dry ice D can be promoted.

[0042] In the above embodiment, furthermore, the tip 23s of the second injection pipe 23 of the carbon dioxide injection section 20 opens into the liquid phase 10a (liquefied carbon dioxide L) in the tank 10 at the bottom of the tank 10. For example, when dry ice D is generated in the tank 10, since the dry ice D has a higher density than the liquefied carbon dioxide, it tends to accumulate at the bottom of the tank 10. On the other hand, since the tip 23s of the second injection pipe 23 of the carbon dioxide injection section 20 opens at the bottom of the tank 10 as described above, the carbon dioxide gas G can be injected at a position closer to the dry ice D deposited at the bottom, and the dry ice D deposited at the bottom can be quickly sublimated.

[0043] In the ship 1 of the above embodiment, furthermore, the carbon dioxide injection section 20 injects the carbon dioxide gas G into the tank 10 when the pressure in the tank 10 becomes equal to or lower than the pressure lower limit value set to be equal to or higher than the triple point pressure of the liquefied carbon dioxide L. By doing so, when the pressure in the tank 10 becomes equal to or lower than the lower limit value of the pressure and the state becomes such that dry ice D is likely to be generated in the tank 10, carbon dioxide gas G can be injected into the tank 10 to suppress the generation of dry ice D in the tank 10.

[0044] In the ship 1 of the above embodiment, further, when the sway of the liquefied carbon dioxide L stored in the tank 10 becomes equal to or higher than a predetermined level, carbon dioxide gas G is injected into the tank 10. Therefore, when the sway of the liquefied carbon dioxide L stored in the tank 10 becomes equal to or higher than a predetermined level, the pressure in the tank 10 can be increased, and thereby the generation of dry ice D in the tank 10 can be suppressed.

[0045] The pressure adjustment method S1 of the tank 10 of the above embodiment includes a step S2 of acquiring at least one of information regarding the pressure in the tank 10 and information regarding the sway of the liquefied carbon dioxide L stored in the tank 10, and a step S4 of injecting carbon dioxide gas G into the tank 10 by the carbon dioxide injection unit 20 based on the acquired information. By doing so, based on the pressure in the tank 10 and the state of the sway of the liquefied carbon stored in the tank 10, the injection of carbon dioxide gas G into the tank 10 can be performed, so that it becomes possible to suppress the generation of dry ice D and smoothly operate the tank 10.

[0046] (Other embodiments) As described above, the embodiments of the present disclosure have been described in detail with reference to the drawings, but the specific configuration is not limited to this embodiment, and design changes and the like within the scope not departing from the gist of the present disclosure are also included. In the ship 1 of the above embodiment, the first injection pipe 22 and the second injection pipe 23 are provided, but only one of the first injection pipe 22 and the second injection pipe 23 may be provided.

[0047] In the ship 1 of the above embodiment, in order to acquire information regarding the pressure in the tank 10, the pressure sensor 24 was provided. However, not only the pressure in the tank 10 but also the temperature of the gas phase 10b in the tank 10 may be detected, and based on the pressure and temperature in the tank 10, it may be determined whether it is necessary to inject the carbon dioxide gas G into the tank 10.

[0048] In the ship 1 of the above embodiment, in order to acquire information regarding the sloshing of the liquid phase 10a in the tank 10, the acceleration sensor 25 was provided. However, any configuration may be used as long as it can detect the sloshing of the liquid phase 10a in the tank 10. For example, the displacement of the liquid level of the liquid phase 10a in the tank 10 may be detected.

[0049] The procedure of the above-described method for adjusting the pressure of the tank can be appropriately changed in terms of specific determination content, order of procedures, and the like.

[0050] <Supplementary Note> The ship 1 described in the embodiment and the method S1 for adjusting the pressure of the tank 10 in the ship 1 can be understood as follows, for example.

[0051] (1) The ship 1 according to the first aspect includes a hull 2, a tank 10 provided in the hull 2 for storing liquefied carbon dioxide L, and a carbon dioxide injection unit 20 provided in the hull 2 and capable of injecting carbon dioxide gas G that is at a higher temperature and pressure than the carbon dioxide in the tank 10 into the tank 10.

[0052] According to this ship 1, the carbon dioxide injection unit 20 can inject carbon dioxide gas G that is at a higher temperature and pressure than the carbon dioxide in the tank 10 into the tank 10. When the state is such that dry ice D is generated in the liquefied carbon dioxide L stored in the tank 10, the carbon dioxide gas G is injected into the tank 10 by the carbon dioxide injection unit 20. Since the carbon dioxide gas G is at a higher temperature and pressure than the carbon dioxide (including both the liquid phase 10a and the gas phase 10b) in the tank 10, a decrease in the pressure in the tank 10 can be suppressed. Also, when dry ice D has been generated in the tank 10, the dry ice D can be sublimated by the carbon dioxide gas G. Therefore, it is possible to suppress the generation of dry ice D and smoothly operate the tank 10.

[0053] (2) The ship 1 according to the second aspect is the ship 1 of (1), and the carbon dioxide injection unit 20 injects the carbon dioxide gas G into the gas phase 10b of the carbon dioxide in the tank 10.

[0054] Thereby, by injecting the carbon dioxide gas G into the gas phase 10b of the carbon dioxide in the tank 10 by the carbon dioxide injection unit 20, the pressure in the tank 10 can be immediately increased.

[0055] (3) The ship 1 according to the third aspect is the ship 1 of (1) or (2), and the carbon dioxide injection unit 20 injects the carbon dioxide gas G into the liquid phase 10a of the carbon dioxide in the tank 10.

[0056] Thereby, by injecting the carbon dioxide gas G into the liquid phase 10a of the carbon dioxide in the tank 10 by the carbon dioxide injection unit 20, when dry ice D is generated in the liquid phase 10a of the carbon dioxide, the carbon dioxide gas G can be sent around the dry ice D. By the injected carbon dioxide gas G, the liquid phase 10a of the carbon dioxide around the dry ice D is gasified, thereby increasing the pressure in the tank 10 and promoting the sublimation of the dry ice D.

[0057] (4) The ship 1 according to the fourth aspect is any one of the ships 1 according to (1) to (3), and when the pressure in the tank 10 becomes equal to or lower than a lower pressure limit value set to be equal to or higher than the triple point pressure of the liquefied carbon dioxide L, the carbon dioxide gas G is injected into the tank 10.

[0058] Thereby, when the pressure in the tank 10 becomes equal to or lower than the lower pressure limit value and it becomes a state where dry ice D is likely to be generated in the tank 10, by injecting the carbon dioxide gas G into the tank 10, the generation of dry ice D in the tank 10 can be suppressed.

[0059] (5) The ship 1 according to the fifth aspect is any one of the ships 1 according to (1) to (4), and when the shaking of the liquefied carbon dioxide L stored in the tank 10 becomes equal to or higher than a predetermined level, the carbon dioxide gas G is injected into the tank 10.

[0060] Thereby, when the shaking of the liquefied carbon dioxide L stored in the tank 10 becomes equal to or higher than a predetermined level, by injecting the carbon dioxide gas G into the tank 10 and increasing the pressure in the tank 10, the generation of dry ice D in the tank 10 can be suppressed. The shaking of the liquefied carbon dioxide L stored in the tank 10 is detected by detecting the acceleration caused by the shaking of the hull 2 and by detecting the displacement of the liquid level of the liquefied carbon dioxide L in the tank 10.

[0061] (6) The pressure adjustment method S1 of the tank 10 in the ship 1 according to the sixth aspect is the pressure adjustment method S1 of the tank 10 in any one of the ships 1 according to (1) to (5), and includes a step S2 of acquiring at least one of information regarding the pressure in the tank 10 and information regarding the shaking of the liquefied carbon dioxide L stored in the tank 10, and a step S4 of injecting the carbon dioxide gas G into the tank 10 by the carbon dioxide injection unit 20 based on the acquired information.

[0062] Accordingly, based on the pressure in the tank 10 and the state of the sloshing of the liquefied carbon stored in the tank 10, by injecting carbon dioxide gas G into the tank 10, the generation of dry ice D can be suppressed, and the operation of the tank 10 can be smoothly carried out. Examples of the information regarding the pressure in the tank 10 include the pressure value in the tank 10 and the temperature of the gas phase 10b in the tank 10. Examples of the information regarding the sloshing of the liquefied carbon dioxide L stored in the tank 10 include the detected value of the acceleration generated by the sloshing of the hull 2 and the detected value of the displacement of the liquid level of the liquefied carbon dioxide L in the tank 10.

Explanation of Reference Numerals

[0063] 1…Ship 2…Hull 2a…Bow 3A, 3B…Side 5…Upper deck 7…Superstructure 8…Cargo space 10…Tank 10a…Liquid phase 10b…Gas phase 12…Cylindrical part 13…End spherical part 20…Carbon dioxide injection part 21…Gas tank 22…First injection pipe 22s…Tip part 22v…On-off valve 23…Second injection pipe 23s…Tip part 23v…On-off valve 24…Pressure sensor 25…Acceleration sensor 60…Control device 61…CPU 62…ROM 63…RAM 64…HDD 65…Signal reception module 70…Signal input part 71…Judgment part 72…On-off control part 75…Output part FA…Bow-stern direction D…Dry ice G…Carbon dioxide gas L…Liquefied carbon dioxide

Claims

1. A hull, a tank provided on the hull for storing liquefied carbon dioxide, a high-temperature and high-pressure gas tank provided on the hull and capable of storing carbon dioxide gas at a temperature and pressure higher than those of the carbon dioxide in the tank, a carbon dioxide injection section capable of injecting the high-temperature and high-pressure carbon dioxide gas stored in the high-temperature and high-pressure gas tank into the tank, and comprising the carbon dioxide injection section injecting the carbon dioxide gas into the tank when the sloshing of the liquefied carbon dioxide stored in the tank reaches a predetermined level a ship.

2. The carbon dioxide injection section injecting the carbon dioxide gas into at least one of the gas phase and the liquid phase of the carbon dioxide in the tank The ship according to Claim 1.

3. The carbon dioxide injection section injecting the carbon dioxide gas into the tank when the pressure in the tank becomes equal to or lower than a lower pressure limit value set to be equal to or higher than the triple point pressure of the liquefied carbon dioxide The ship according to Claim 1 or 2.

4. The design pressure of the high-temperature and high-pressure gas tank is 5 to 15.7 MPa, and the high-temperature and high-pressure gas tank stores the carbon dioxide gas at a temperature higher than that of the carbon dioxide in the tank and at normal temperature The ship according to any one of Claims 1 to 3.

5. A hull, a tank provided on the hull for storing liquefied carbon dioxide, a carbon dioxide injection section provided on the hull and capable of injecting carbon dioxide gas at a temperature and pressure higher than those of the carbon dioxide in the tank into the tank, and comprising the carbon dioxide injection section injecting the carbon dioxide gas into the liquid phase of the carbon dioxide in the tank a ship.

6. A hull, a tank provided on the hull for storing liquefied carbon dioxide, a carbon dioxide injection section provided on the hull and capable of injecting carbon dioxide gas at a temperature and pressure higher than those of the carbon dioxide in the tank into the tank, and comprising the carbon dioxide injection section injecting the carbon dioxide gas into the tank when the sloshing of the liquefied carbon dioxide stored in the tank reaches a predetermined level a ship.

7. A method for adjusting the pressure of a tank in the ship according to any one of Claims 1 to 6, comprising: a step of obtaining at least one of information regarding the pressure in the tank and information regarding the sloshing of the liquefied carbon dioxide stored in the tank; and a step of injecting the carbon dioxide gas into the tank by the carbon dioxide injection section based on the obtained information. Method for adjusting the pressure of a tank on a ship.

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