Method and floating body for loading and unloading liquefied carbon dioxide

Abstract

The method for loading and unloading liquefied carbon dioxide includes: a process of connecting a connecting pipe for connecting to external equipment arranged outside the floating body to a pipe connected to the interior of a tank provided in a floating body; a process of supplying a replacement gas whose moisture content is adjusted to below a prescribed upper limit value into the interior of the connecting pipe and the pipe to replace the interior of the connecting pipe and the pipe with the replacement gas; a process of replacing the interior of the connecting pipe and the pipe from the replacement gas to carbon dioxide gas; and a process of loading and unloading liquefied carbon dioxide between the external equipment and the tank through the connecting pipe and the pipe.

Description

Technical Field

[0001] The invention relates to a loading and unloading method of liquefied carbon dioxide and a floating body.

[0002] This application claims priority based on patent application No. 2020-180560 filed in Japan on October 28, 2020, and incorporates the contents thereof herein. Background Art

[0003] For example, Patent Document 1 discloses a structure equipped with a transfer device (natural gas transfer device) for transferring liquefied natural gas (LNG) from a ship (import vessel) equipped with tanks storing liquefied natural gas to a facility on land (import terminal). In this structure, the ship, moored at the facility on land, is in fluid communication with the facility, transferring the liquefied gas in the tank to a storage tank on land.

[0004] Previous technical literature

[0005] Patent Literature

[0006] Patent Document 1: Japanese Patent Application No. 2010-503132 Summary of the Invention

[0007] Technical issues to be solved by the invention

[0008] When loading liquefied gas into a tank from external equipment, such as land-based facilities, or unloading liquefied gas from a tank to an external facility, the tank's loading and unloading pipes, including those onboard, are connected to the external equipment via connecting pipes. However, when connecting the connecting pipes to the pipes, air (atmosphere) may intrude into the pipes. If air intrudes into the pipes when the tank contains liquefied carbon dioxide, the moisture in the air reacts with the carbon dioxide to form carbonic acid and hydrates. The formation of carbonic acid and hydrates in this manner may cause corrosion in the pipes and the interior of the tank.

[0009] Therefore, a process is performed as follows: after connecting a connecting pipe to the piping of the tank, the connecting pipe is filled with carbon dioxide gas. This prevents moisture in the air from directly contacting the liquefied carbon dioxide. However, during this process, the moisture in the air in the connecting pipe reacts with the carbon dioxide during the carbon dioxide filling, potentially causing corrosion inside the tank and piping.

[0010] The present invention has been made to solve the above-mentioned problems, and its object is to provide a method for loading and unloading liquefied carbon dioxide and a floating body that can suppress the reaction between carbon dioxide and water during loading and unloading of liquefied carbon dioxide and can suppress the corrosion inside the tank and piping.

[0011] Means for solving technical problems

[0012] In order to solve the above-mentioned problems, the method for loading and unloading liquefied carbon dioxide according to the present invention includes the steps of connecting a connecting pipe, replacing with a replacement gas, replacing with carbon dioxide gas, and loading and unloading the liquefied carbon dioxide. In the step of connecting the connecting pipe, the connecting pipe is connected to a pipe that communicates with the interior of a tank provided in a floating body. The connecting pipe is used to connect the pipe to an external device disposed outside the floating body. In the step of replacing with the replacement gas, replacement gas is fed into the interior of the connecting pipe and the pipe to replace the interior of the connecting pipe and the pipe with the replacement gas. The moisture content of the replacement gas is adjusted to be below a predetermined upper limit. In the step of replacing with carbon dioxide gas, the interior of the connecting pipe and the pipe is replaced with carbon dioxide gas from the replacement gas. In the step of loading and unloading the liquefied carbon dioxide, the liquefied carbon dioxide is loaded and unloaded between the external device and the tank via the connecting pipe and the pipe.

[0013] The floating body involved in the present invention includes a floating body main body, a tank, a piping, a replacement gas supply unit and a carbon dioxide supply unit. The tank is arranged on the floating body main body. The tank is capable of storing liquefied carbon dioxide. The piping is connected to the inside of the tank. The piping is capable of connecting a connecting pipe for transporting liquefied carbon dioxide between an external device and the tank. When the connecting pipe is connected to the piping, the replacement gas supply unit feeds replacement gas into the piping and the inside of the connecting pipe. The moisture content of the replacement gas is adjusted to be below a predetermined upper limit. The carbon dioxide supply unit feeds carbon dioxide gas into the piping and the inside of the connecting pipe.

[0014] Effects of the Invention

[0015] According to the method for loading and unloading liquefied carbon dioxide and the floating body of the present invention, it is possible to suppress the reaction between carbon dioxide and moisture during loading and unloading of liquefied carbon dioxide and to suppress the occurrence of corrosion inside the tank and the piping. BRIEF DESCRIPTION OF THE DRAWINGS

[0016] Figure 1 It is a plan view showing a schematic structure of a ship as a floating body according to an embodiment of the present invention.

[0017] Figure 2 This is a diagram showing tanks and piping installed on a ship according to an embodiment of the present invention, and is a diagram showing a tank and piping installed on a ship according to an embodiment of the present invention. Figure 1 A cross-sectional view taken along the line II.

[0018] Figure 3This is a diagram showing tanks and piping installed on a ship according to an embodiment of the present invention, and is a diagram showing a tank and piping installed on a ship according to an embodiment of the present invention. Figure 1 A sectional view taken along the line II-II.

[0019] Figure 4 It is a diagram showing external equipment connected to the ship according to the embodiment of the present invention via a connecting pipe.

[0020] Figure 5 This is a flowchart showing the steps of a method for loading and unloading liquefied carbon dioxide according to an embodiment of the present invention.

[0021] Figure 6 This is a diagram showing a process of connecting a connection pipe in the liquefied carbon dioxide loading and unloading method according to the embodiment of the present invention.

[0022] Figure 7 This is a diagram showing a step of replacing liquefied carbon dioxide with a replacement gas in the method for loading and unloading liquefied carbon dioxide according to the embodiment of the present invention.

[0023] Figure 8 This is a diagram showing a process of replacing liquefied carbon dioxide with carbon dioxide gas in the method for loading and unloading liquefied carbon dioxide according to the embodiment of the present invention.

[0024] Figure 9 This is a diagram showing the steps of loading and unloading liquefied carbon dioxide in the method for loading and unloading liquefied carbon dioxide according to the embodiment of the present invention. DETAILED DESCRIPTION

[0025] Below, reference Figures 1 to 9 A floating body and a method for loading and unloading liquefied carbon dioxide according to an embodiment of the present invention will be described.

[0026] (Ship Structure)

[0027] like Figure 1 、 Figure 2 As shown, in the embodiment of the present invention, a ship 1 as a floating body transports liquefied carbon dioxide. The ship 1 includes at least a hull 2 as a floating body, a tank device 10, and a replacement gas supply unit 20 (see FIG. Figure 2 ) and the carbon dioxide supply unit 30 (reference Figure 2 ).

[0028] (Structure of the hull)

[0029] The hull 2 has a pair of side panels 3A and 3B constituting its outer shell, and a bottom 4 (see Figure 2 ) and the upper deck 5. The side 3A, 3B has a pair of side plates forming the left and right sides of the ship width direction Dw. The bottom 4 is arranged below in the up-down direction Dv and has a bottom plate connecting these side 3A, 3B. Figure 2 As shown, the outer shell of the hull 2, formed by the pair of side panels 3A and 3B and the bottom 4, forms a U-shape in a cross-section perpendicular to the bow-stern direction Da. In this embodiment, the upper deck 5 is a fully exposed deck. In the hull 2, a superstructure 7 having a living area is formed on the upper deck 5 on the stern 2b side.

[0030] A cargo loading section (cargo hold) 8 is formed in the hull 2 on the bow 2a side relative to the superstructure 7. The cargo loading section 8 is recessed toward the bottom of the ship below the upper deck 5 and is open upward.

[0031] (Structure of tank equipment)

[0032] A plurality of tank facilities 10 are arranged along the bow and stern direction Da in the cargo loading section 8. In the embodiment of the present invention, two tank facilities 10 are arranged at intervals in the bow and stern direction Da.

[0033] like Figure 2 、 Figure 3 As shown, the tank facility 10 includes at least a tank 11 and a pipe 12 .

[0034] In this embodiment, the tank 11 is disposed on the hull 2. The tank 11 has, for example, a horizontally extending cylindrical shape. In this embodiment, the tank 11 is positioned with its major axis aligned with the bow-stern direction Da. The tank 11 contains liquefied carbon dioxide L. The tank 11 is not limited to a cylindrical shape; it may also have a spherical, rectangular, or other shape.

[0035] The piping 12 includes a loading piping 13 and an unloading piping 14. That is, the piping 12 of the tank facility 10 includes two types of piping: the loading piping 13 and the unloading piping 14.

[0036] like Figure 3 As shown, the loading pipe 13 is used to supply liquefied carbon dioxide from land to external equipment 100 (see Figure 4 ) is loaded into the tank 11. A portion of the loading pipe 13 near one end 13a thereof passes through the top of the tank 11 and extends from the outside to the inside of the tank 11. The portion of the loading pipe 13 near one end 13a extends in the vertical direction Dv within the tank 11. The one end 13a of the loading pipe 13 opens into the tank 11 at the bottom of the tank 11.

[0037] The remaining portion of the loading pipe 13, that is, the portion close to the other end 13b, is disposed outside the tank 11. Figure 2As shown, a connection portion 13j for connecting to the outside of the ship is provided at the other end 13b of the loading pipe 13. The connection portion 13j may include, for example, a flange. The connection portion 13j is positioned toward either side 3A or 3B (e.g., side 3A). The opening of the connection portion 13j is typically closed by a cap (not shown). By removing this cap (not shown), the end of the connecting pipe 50 for connecting to the equipment-side tank 101 of the external equipment 100 can be connected to the connection portion 13j in place of the cap (not shown).

[0038] The unloading pipe 14 delivers the liquefied carbon dioxide L in the tank 11 to an external device 100 outside the ship. A portion of the unloading pipe 14, near one end 14a, extends from the outside of the tank 11 through the top of the tank 11 and into the interior of the tank 11. One end 14a of the unloading pipe 14 is disposed at the lower portion of the tank 11. A pump (not shown) is provided at one end 14a of the unloading pipe 14. The pump (not shown) draws the liquefied carbon dioxide L in the tank 11 and delivers it to the unloading pipe 14. The unloading pipe 14 guides the liquefied carbon dioxide L delivered by the pump to the outside of the tank 11 (outside the ship).

[0039] The remaining portion of the unloading pipe 14, which is closer to the other end 14b, is disposed outside the tank 11. Figure 2 As shown, a connection portion 14j for connecting to the outside of the ship is provided at the other end 14b of the unloading pipe 14. The connection portion 14j may have, for example, a flange, and is positioned facing either side 3A or 3B (e.g., side 3A). The opening of the connection portion 14j is typically closed by a cap (not shown). By removing this cap (not shown), the end of the connecting pipe 50 for connecting to the equipment-side tank 101 of the external equipment 100 can be connected to the connection portion 14j in place of the cap (not shown).

[0040] like Figure 4 As shown, when loading liquefied carbon dioxide L from external equipment 100 into tank 11, connecting pipe 50 connects the equipment-side piping 102 provided on the equipment-side tank 101 of external equipment 100 with connecting portion 13j of loading piping 13, thereby establishing communication therewith. Furthermore, when unloading liquefied carbon dioxide L from tank 11 to external equipment 100, connecting pipe 50 connects the equipment-side piping 102 provided on the equipment-side tank 101 of external equipment 100 with connecting portion 14j of unloading piping 14, thereby establishing communication therewith. In the following description, except when distinguishing between loading piping 13 and unloading piping 14, loading piping 13 and unloading piping 14 are referred to simply as piping 12, and connecting portions 13j and 14j are referred to simply as connecting portions 12j.

[0041] On-off valves 15 and 105 are installed on the pipe 12 and the equipment-side pipe 102 on the external device 100 side, respectively. On-off valve 15 opens and closes the flow path within the pipe 12. On-off valve 105 opens and closes the flow path within the equipment-side pipe 102. Furthermore, an opening valve 106 is installed on the equipment-side pipe 102. When opening valve 106 is opened, the flow path within the equipment-side pipe 102 communicates with the outside. When on-off valves 15 and 105 are closed while the equipment-side pipe 102 and pipe 12 are connected by connecting pipe 50, the pipe 12, connecting pipe 50, and the interior of the equipment-side pipe 102 between on-off valve 15 and on-off valve 105 are disconnected from the equipment-side tanks 101 and 11. The outside to which the flow path within the equipment-side pipe 102 communicates is not limited to the atmosphere. For example, it may be a container such as a tank capable of storing gas released through opening valve 106.

[0042] like Figure 2 As shown, in a state where the connecting pipe 50 for connecting to the external device 100 is connected to the piping 12, the replacement gas supply unit 20 sends replacement gas Ga into the inside of the piping 12 and the connecting pipe 50. As the replacement gas Ga, a gas that does not chemically react with carbon dioxide can be used. The moisture content of the replacement gas Ga is adjusted to below a prescribed upper limit. As such a replacement gas Ga, inert gases such as air (so-called dry air), nitrogen, and argon whose moisture content is adjusted to below a prescribed upper limit can be used. In this embodiment, dry air can be used as the replacement gas Ga. The replacement gas supply unit 20 is provided with an air dryer 21. The air dryer 21 generates dry air whose moisture content is adjusted to a prescribed upper limit (for example, a dew point temperature of below -40°C) by removing moisture from the atmosphere taken in from the outside. The air dryer 21 is connected to the piping 12 via a replacement gas supply pipe 22. An on-off valve 23 is provided on the replacement gas supply pipe 22. By opening the on-off valve 23, the dry air generated by the air dryer 21 is fed into the interior of the pipe 12, the connecting pipe 50, and the equipment-side pipe 102 through the replacement gas supply pipe 22. The upper limit of the moisture content in the dry air can be any value that allows efficient removal of moisture from the pipes and can be determined in advance through experiments, etc.

[0043] like Figure 2 、 Figure 4 As shown, when the connecting pipe 50 for connecting to the external device 100 is connected to the piping 12, the carbon dioxide supply unit 30 supplies carbon dioxide gas Gc to the interior of the piping 12, the connecting pipe 50, and the device-side piping 102. In this embodiment, the carbon dioxide supply unit 30 can use the boil-off gas generated by gasifying the liquefied carbon dioxide L in the tank 11 as the carbon dioxide gas Gc. The carbon dioxide supply unit 30 is equipped with a boil-off gas delivery pipe 31 (see Figure 2 、 Figure 3 The boil-off gas delivery pipe 31 connects the upper gas phase in the tank 11 to the pipe 12. The carbon dioxide supply unit 30 delivers boil-off gas from the tank 11 through the pipe 12 to the connection pipe 50 and the equipment-side pipe 102.

[0044] (Steps of the Liquefied Carbon Dioxide Transport Method)

[0045] like Figure 5 As shown, the method S10 for loading and unloading liquefied carbon dioxide L according to this embodiment includes a step S11 of connecting the connection pipe 50 , a step S12 of replacing with replacement gas Ga, a step S13 of replacing with carbon dioxide gas Gc, and a step S14 of loading and unloading the liquefied carbon dioxide L.

[0046] In the step S11 of connecting the connecting pipe 50, as shown in FIG. Figure 6 As shown, one end of a connecting pipe 50 for connecting to an external device 100 is connected to the pipe 12. Furthermore, the other end of the connecting pipe 50 is connected to the device-side pipe 102 of the external device 100. At this point, the on-off valves 15, 23, and 105 and the open valve 106 are previously closed. In this state, atmospheric air enters the pipe 12, connecting pipe 50, and device-side pipe 102 between the on-off valves 15 and 105.

[0047] In the step S12 of replacing the gas Ga, Figure 7 As shown, replacement gas Ga is supplied into the interior of the connecting pipe 50 via the replacement gas supply unit 20. To this end, the air dryer 21 is operated, the on-off valves 15 and 105 are closed, and the on-off valve 23 and the open valve 106 are opened. The air dryer 21 removes moisture from the air (atmosphere) drawn in from the outside, generating dry air with a moisture content adjusted to below a predetermined upper limit. This dry air becomes the replacement gas Ga. This replacement gas Ga is supplied to the connection portion 12j of the piping 12 via the replacement gas supply pipe 22. The supplied replacement gas Ga flows from the piping 12 to the connecting pipe 50 and the equipment-side piping 102, sequentially pushing the air inside the piping 12, the connecting pipe 50, and the equipment-side piping 102 outward through the open valve 106. The dew point of the air discharged from the open valve 106 is measured, and the supply of replacement gas Ga continues until the dew point falls within a pre-set tolerance range. Once the measured dew point falls within the allowable range, the replacement gas Ga supplied by the replacement gas supply unit 20 is stopped, and the open valve 106 and the on-off valve 23 are closed. This allows the interior of the pipe 12, connecting pipe 50, and facility-side pipe 102 between the on-off valves 15 and 105 to be replaced with the replacement gas Ga.

[0048] In the step S13 of replacing the gas with carbon dioxide gas Gc, the interior of the connecting pipe 50 is replaced with the replacement gas Ga and the carbon dioxide gas Gc. Figure 8 As shown, on-off valves 15 and 105 are opened, while open valve 106 and on-off valve 23 are closed. In this state, evaporated gas from tank 11 is fed into connecting pipe 50 and device-side pipe 102 via carbon dioxide supply unit 30 and piping 12 as carbon dioxide gas Gc. Consequently, replacement gas Ga (dry air) within piping 12, connecting pipe 50, and device-side pipe 102 is sequentially expelled toward external device 100. On external device 100, the carbon dioxide concentration of the mixed gas of replacement gas Ga and carbon dioxide gas Gc extruded from connecting pipe 50 is measured. Once the measured carbon dioxide concentration falls within a pre-set concentration range, the supply of carbon dioxide gas Gc by carbon dioxide supply unit 30 is stopped.

[0049] In the step S14 of loading and unloading liquefied carbon dioxide L, Figure 9 As shown, liquefied carbon dioxide L is loaded and unloaded between the external device 100 and the tank 11 via the connecting pipe 50 and the pipe 12. For example, when loading liquefied carbon dioxide L from the external device 100 into the tank 11, the liquefied carbon dioxide L is fed from the device-side tank 101 of the external device 100 into the tank 11 via the device-side pipe 102, the connecting pipe 50, and the pipe 12 (loading pipe 13).

[0050] When unloading the liquefied carbon dioxide L from the tank 11 to the external device 100 , the liquefied carbon dioxide L is fed from the pipe 12 (unloading pipe 14 ) through the connecting pipe 50 and the device-side pipe 102 to the device-side tank 101 of the external device 100 .

[0051] (Effect)

[0052] According to the method S10 for loading and unloading liquefied carbon dioxide of the above-mentioned embodiment, after the interior of the connecting pipe 50 and the piping 12 is replaced with the replacement gas Ga, it is further replaced with the carbon dioxide gas Gc. The moisture content of the replacement gas Ga is adjusted to be below the prescribed upper limit. Thus, the reaction between the carbon dioxide gas Gc and moisture is suppressed when the replacement gas Ga is replaced with the carbon dioxide gas Gc. After the interior of the connecting pipe 50 and the piping 12 is replaced with the carbon dioxide gas Gc, the liquefied carbon dioxide L loaded and unloaded between the external device 100 and the tank 11 flows into the interior of the connecting pipe 50 and the piping 12, so the reaction between the carbon dioxide gas Gc and moisture is also suppressed at this time. Therefore, the reaction between carbon dioxide and moisture can be suppressed when loading and unloading the liquefied carbon dioxide L, and the corrosion of the interior of the tank 11 and the piping 12 can be suppressed.

[0053] The replacement gas Ga is dry air whose moisture content is adjusted to a predetermined upper limit or less. The dry air used as the replacement gas Ga can be generated by drying air (atmosphere) using the air dryer 21. Therefore, dry air can be easily prepared on the ship 1.

[0054] The carbon dioxide gas Gc is boil-off gas generated by gasifying the liquefied carbon dioxide L stored in the tank 11. Thus, the carbon dioxide gas Gc can be easily obtained on the ship 1.

[0055] In the vessel 1 of the above-described embodiment, when the connecting pipe 50 for connecting to the external equipment 100 is connected to the pipe 12, the replacement gas supply unit 20 supplies replacement gas Ga, whose moisture content is adjusted to below a predetermined upper limit, into the connecting pipe 50 and the pipe 12. This allows the interior of the connecting pipe 50 and the pipe 12 to be replaced with the replacement gas Ga. Furthermore, by supplying carbon dioxide gas Gc into the connecting pipe 50 and the pipe 12 from the carbon dioxide supply unit 30, the interior of the connecting pipe 50 and the pipe 12 can be replaced with the replacement gas Ga. Subsequently, liquefied carbon dioxide L is loaded and unloaded between the external equipment 100 and the tank 11 via the connecting pipe 50 and the pipe 12. This prevents the reaction between carbon dioxide and moisture during loading and unloading, and also prevents corrosion within the tank 11 and the pipe 12.

[0056] Furthermore, the vessel 1 is equipped with an air dryer 21. By drying the ambient air (air) taken in from the outside with the air dryer 21, dry air with a moisture content adjusted to a predetermined upper limit or below can be provided as the replacement gas Ga. Consequently, the replacement gas Ga with a moisture content adjusted to a predetermined upper limit or below can be easily obtained on the vessel 1.

[0057] Furthermore, the ship 1 sends boil-off gas generated by gasifying the liquefied carbon dioxide L stored in the tank 11 as carbon dioxide gas Gc into the pipe 12 and the connecting pipe 50. This allows the ship 1 to easily obtain the carbon dioxide gas Gc.

[0058] (Other embodiments)

[0059] While the embodiment of the present invention has been described in detail with reference to the drawings, the specific configuration is not limited to the embodiment and includes design changes within the scope not departing from the gist of the present invention.

[0060] In the above embodiment, the connection portion 13j of the loading pipe 13 and the connection portion 14j of the unloading pipe 14 are provided separately as the connection portion 12j of the pipe 12, but this is not limiting. For example, the loading pipe 13 and the unloading pipe 14 may be connected to a single pipe 12 at the other ends 13b and 14b, and the connection portion 12j may be shared by the loading pipe 13 and the unloading pipe 14.

[0061] Furthermore, in the above embodiment, liquefied carbon dioxide L is loaded and unloaded between the ship 1 and the external equipment 100 located on land, but this is not limiting. Liquefied carbon dioxide L can also be loaded and unloaded between the ship 1 and an offshore floating facility that is located at sea and does not have a propulsion mechanism. In this case, the offshore floating facility corresponds to the external equipment 100 when viewed from the ship 1.

[0062] In the above embodiment, boil-off gas generated by gasifying liquefied carbon dioxide L in the tank 11 is used as the carbon dioxide gas Gc. However, the carbon dioxide gas Gc may be other than boil-off gas, for example, carbon dioxide gas contained in another container on or off the same ship.

[0063] Furthermore, in the above-described embodiment, the ship 1 is configured to include two tanks 11, but the number and arrangement of the tanks 11 are not limited thereto. Three or more tanks 11 may be provided. Furthermore, in the above-described embodiment, the case where a plurality of tanks 11 are arranged along the bow and stern direction Da is illustrated, but the tanks 11 may also be arranged along the width direction (in other words, the port and starboard directions). Furthermore, in the above-described embodiment, the ship 1 is illustrated as a floating body, but this is not limited thereto. The floating body may be an offshore floating body equipment that does not include a propulsion mechanism. In the case where the floating body is an offshore floating body equipment, the external equipment 100 viewed from the offshore floating body equipment may also become a ship.

[0064] <Note>

[0065] The loading and unloading method S10 of the liquefied carbon dioxide L and the floating body 1 described in each embodiment can be understood, for example, as follows.

[0066] (1) The loading and unloading method S10 of liquefied carbon dioxide L involved in the first embodiment includes: a process S11 of connecting a connecting pipe 50 for connecting to an external device 100 arranged outside the floating body 1 to a piping 12 connected to the interior of a tank 11 provided in the floating body 1; a process S12 of supplying a replacement gas Ga whose moisture content is adjusted to below a prescribed upper limit value into the interior of the connecting pipe 50 and the piping 12 to replace the interior of the connecting pipe 50 and the piping 12 with the replacement gas Ga; a process S13 of replacing the interior of the connecting pipe 50 and the piping 12 from the replacement gas Ga to carbon dioxide gas Gc; and a process S14 of loading and unloading liquefied carbon dioxide L between the external device 100 and the tank 11 through the connecting pipe 50 and the piping 12.

[0067] Examples of the floating body 1 include ships and offshore floating equipment. Examples of the floating body main body 2 include a ship hull and the floating body main body 2 of offshore floating equipment.

[0068] Examples of the replacement gas Ga include dry air and inert gas.

[0069] According to this method S10 for loading and unloading liquefied carbon dioxide L, after the interior of the connecting pipe 50 and the piping 12 is replaced with the replacement gas Ga, it is further replaced with carbon dioxide gas Gc. The moisture content of the replacement gas Ga is adjusted to below a predetermined upper limit, thereby suppressing the reaction between carbon dioxide and moisture when the replacement gas Ga is replaced with carbon dioxide gas Gc. After the interior of the connecting pipe 50 and the piping 12 is replaced with the carbon dioxide gas Gc, the liquefied carbon dioxide L loaded and unloaded between the external equipment 100 and the tank 11 flows into the interior of the connecting pipe 50 and the piping 12, thereby also suppressing the occurrence of a reaction between carbon dioxide and moisture at this time. Therefore, it is possible to suppress the reaction between carbon dioxide and moisture during loading and unloading of the liquefied carbon dioxide L, and to prevent corrosion inside the tank 11 and the piping 12.

[0070] (2) The liquefied carbon dioxide L loading and unloading method S10 according to the second embodiment is the liquefied carbon dioxide L loading and unloading method S10 according to (1), wherein the replacement gas Ga is dry air whose moisture content is adjusted to a predetermined upper limit or less.

[0071] Thus, dry air used as the replacement gas Ga can be generated by drying air (atmosphere) with an air dryer. Therefore, dry air can be easily prepared on the floating body 1.

[0072] (3) The method S10 for loading and unloading liquefied carbon dioxide L according to the third embodiment is the method S10 for loading and unloading liquefied carbon dioxide L according to (1) or (2), wherein the carbon dioxide gas Gc is boil-off gas generated by gasifying the liquefied carbon dioxide L stored in the tank 11.

[0073] This makes it possible to easily obtain the carbon dioxide gas Gc on the floating body 1 .

[0074] (4) The float 1 involved in the fourth embodiment comprises: a float body 2; a tank 11, which is arranged on the float body 2 and can store liquefied carbon dioxide L; a piping 12, which is connected to the inside of the tank 11 and can be connected to a connecting pipe 50 for transporting liquefied carbon dioxide L between an external device 100 and the tank 11; a replacement gas supply unit 20, which, when the connecting pipe 50 is connected to the piping 12, feeds a replacement gas Ga whose moisture content is adjusted to below a prescribed upper limit value into the inside of the piping 12 and the connecting pipe 50; and a carbon dioxide supply unit 30, which feeds carbon dioxide gas Gc into the inside of the piping 12 and the connecting pipe 50.

[0075] In this floating structure 1, the replacement gas Ga, whose moisture content is adjusted to below a predetermined upper limit, is supplied from the replacement gas supply unit 20 into the connecting pipe 50 and the pipe 12, thereby replacing the interior of the connecting pipe 50 and the pipe 12 with the replacement gas Ga. Furthermore, the carbon dioxide gas supply unit 30 supplies carbon dioxide gas Gc into the connecting pipe 50 and the pipe 12, thereby replacing the interior of the connecting pipe 50 and the pipe 12 with the replacement gas Ga. Subsequently, liquefied carbon dioxide L is loaded and unloaded between the external device 100 and the tank 11 via the connecting pipe 50 and the pipe 12. This prevents the reaction between carbon dioxide and moisture during loading and unloading of the liquefied carbon dioxide L, and also suppresses corrosion within the tank 11 and the pipe 12.

[0076] (5) The floating body 1 according to the fifth aspect is the floating body 1 according to (4), wherein the replacement gas supply unit 20 includes an air dryer 21 that reduces moisture contained in the air taken in from the outside.

[0077] Thus, by reducing the moisture contained in the air taken in from the outside by the air dryer 21 , dry air can be provided as the replacement gas Ga whose moisture content is adjusted to a predetermined upper limit value or less.

[0078] (6) The float 1 involved in the sixth embodiment is the float 1 of (4) or (5), wherein the carbon dioxide supply unit 30 sends the evaporated gas generated by gasifying the liquefied carbon dioxide L stored in the tank 11 into the interior of the piping 12 and the connecting pipe 50 as the carbon dioxide gas Gc.

[0079] Thus, by using the boil-off gas as the carbon dioxide gas Gc, the carbon dioxide gas Gc can be easily obtained on the floating body 1 .

[0080] Industrial applicability

[0081] According to the method for loading and unloading liquefied carbon dioxide and the floating body of the present invention, it is possible to suppress the reaction between carbon dioxide and moisture during loading and unloading of liquefied carbon dioxide and to suppress the occurrence of corrosion inside the tank and the piping.

[0082] Explanation of symbols

[0083] 1-Ship (floating body), 2-Hull (floating body body), 2a-Bow, 2b-Stern, 3A, 3B-Side, 4-Bottom, 5-Upper deck, 7-Upper structure, 8-Cargo loading section, 10-Tank equipment, 11-Tank, 12-Pipe, 12j-Connection, 13-Loading piping, 13a-One end, 13b-Other end, 13j-Connection, 14-Unloading piping, 14a-One end, 14b-Other end One end, 14j-connecting part, 15-on / off valve, 20-replacement gas supply part, 21-air dryer, 22-replacement gas supply pipe, 23-on / off valve, 30-carbon dioxide supply part, 50-connecting pipe, 100-external equipment, 101-equipment side tank, 102-equipment side piping, 105-on / off valve, 106-opening valve, Ga-replacement gas, Gc-carbon dioxide gas, L-liquefied carbon dioxide.

Claims

1. A method for loading and unloading liquefied carbon dioxide, comprising: A step of connecting a connection pipe for connecting to external equipment disposed outside the floating body to a pipe communicating with the interior of a tank provided in the floating body; a step of supplying a replacement gas whose moisture content is adjusted to be below a predetermined upper limit value into the interior of the connecting pipe and the piping, thereby replacing the interior of the connecting pipe and the piping with the replacement gas, the replacement gas being dry air whose moisture content is adjusted to be below a predetermined upper limit value obtained by drying air taken in from the outside by an air dryer provided in the floating body; a step of replacing the interior of the connecting pipe and the piping with carbon dioxide gas from the replacement gas; and A step of loading and unloading liquefied carbon dioxide between the external equipment and the tank via the connecting pipe and the piping.

2. The method for loading and unloading liquefied carbon dioxide according to claim 1, wherein: The carbon dioxide gas is boil-off gas generated by gasifying liquefied carbon dioxide stored in the tank.

3. A floating body comprising: floating body main body; a tank, disposed on the floating body and capable of storing liquefied carbon dioxide; a pipe communicating with the interior of the tank and capable of being connected to a connecting pipe for transporting liquefied carbon dioxide between an external device and the tank; a replacement gas supply unit for supplying replacement gas whose moisture content is adjusted to be below a predetermined upper limit value into the interior of the piping and the connecting pipe when the connecting pipe is connected to the piping, the replacement gas being dry air whose moisture content is adjusted to be below a predetermined upper limit value obtained by drying air taken in from the outside by an air dryer provided in the floating body; and The carbon dioxide supply unit supplies carbon dioxide gas into the pipe and the connecting pipe.

4. The floating body according to claim 3, wherein: The carbon dioxide supply unit feeds boil-off gas generated by gasifying liquefied carbon dioxide stored in the tank into the pipe and the connecting pipe as the carbon dioxide gas.

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