JP7561574B2 - Floating body, method for loading liquefied carbon dioxide, and method for unloading liquefied carbon dioxide - Google Patents

Description

This disclosure relates to a floating body, a method for loading liquefied carbon dioxide, and a method for unloading liquefied carbon dioxide.

For example, the fuel tank disclosed in Patent Document 1 is configured to include a loading pipe (pipeline) for loading liquefied natural gas (LNG) into the fuel tank.

Special table 2018-528119 publication

When liquefied carbon dioxide is stored in a tank, the liquefied carbon dioxide may solidify and produce dry ice for the following reasons. That is, the pressure of the liquefied carbon dioxide at the lower end of the loading pipe or the unloading pipe that opens into the tank corresponds to the tank operating pressure. In the configuration disclosed in Patent Document 1, the top of the pipe, which is the highest position in the loading pipe or the unloading pipe, is located above the highest liquid level in the tank. The pressure of the liquefied carbon dioxide at the top of the pipe is lower than the pressure of the liquefied carbon dioxide at the lower end of the pipe by an amount corresponding to the head pressure due to the height difference between the liquid level of the liquefied carbon dioxide in the tank and the top of the pipe. That is, in the loading pipe or the unloading pipe, the pressure of the liquefied carbon dioxide at the top of the pipe is lower than the pressure of the liquefied carbon dioxide in the tank.

The triple point pressure of liquefied carbon dioxide, where the gas, liquid, and solid phases coexist (triple point pressure), is higher than that of LNG or LPG, and the difference with the tank operating pressure during operation is small. As a result, depending on the tank operating pressure (tank design pressure), the pressure of liquefied carbon dioxide at the top of the piping, where the pressure of liquefied carbon dioxide is lowest, may fall below the triple point pressure, causing flash evaporation of liquefied carbon dioxide. The latent heat of evaporation of liquefied carbon dioxide then causes a drop in the temperature of the liquefied carbon dioxide that remains unevaporated, causing the liquefied carbon dioxide to solidify at the top of the piping and produce dry ice. If dry ice is produced in the loading or unloading piping, the flow of liquefied carbon dioxide in the piping is obstructed, which may affect the loading and unloading operations of liquefied carbon dioxide.

The present disclosure has been made to solve the above problems, and aims to provide a float that suppresses the generation of dry ice in the piping and enables smooth loading and unloading of liquefied carbon dioxide, a method for loading liquefied carbon dioxide, and a method for unloading liquefied carbon dioxide.

In order to solve the above problems, a float according to the present disclosure includes a float body, a tank, and a loading pipe. The tank is disposed in the float body. The tank is capable of storing liquefied carbon dioxide. The loading pipe discharges liquefied carbon dioxide supplied from the outside into the tank. The loading pipe includes a first loading pipe and a second loading pipe. The first loading pipe is disposed outside the tank and extends horizontally above the tank. The first loading pipe has a first inner diameter. The second loading pipe has one end connected to the first loading pipe and extends from the outside to the inside of the tank, and extends in the vertical direction within the tank, with the other end, which is the lower end in the vertical direction, opening within the tank. The second loading pipe has a second inner diameter smaller than the first inner diameter.

The float according to the present disclosure comprises a float body, a plurality of tanks, a lifting pipe, and a transfer pipe. The tank is disposed in the float body. The tank is capable of storing liquefied carbon dioxide. The lifting pipe is provided in each of the plurality of tanks. The lifting pipe sends out the liquefied carbon dioxide in the tank to the outside of the float body. The transfer pipe is disposed so as to straddle between the first tank and the second tank. The transfer pipe communicates the inside of the first tank with the inside of the second tank. The transfer pipe comprises a first transfer pipe and a second transfer pipe. The first transfer pipe is disposed on the first tank side. The transfer pipe has a first inner diameter. One end of the second transfer pipe is connected to the first transfer pipe, and the other end opens in the second tank. The second transfer pipe has a second inner diameter smaller than the first inner diameter. The first transfer piping is arranged outside both the first tank and the second tank and has an intermediate portion extending horizontally above the first tank and the second tank, and the second transfer piping extends from the outside to the inside of the second tank and extends in the vertical direction within the second tank , with the lower end of the second transfer piping opening within the second tank as the other end .

The method of loading liquefied carbon dioxide according to the present disclosure is a method of loading liquefied carbon dioxide in a floating body as described above. The method of loading liquefied carbon dioxide includes a step of loading liquefied carbon dioxide into the tank from the first loading pipe through the second loading pipe, and a step of loading liquefied carbon dioxide into the tank from the first loading pipe through the third loading pipe when the liquid level of the liquefied carbon dioxide in the tank reaches a predetermined liquid level.

The method for unloading liquefied carbon dioxide according to the present disclosure is a method for unloading liquefied carbon dioxide in a floating body as described above. The method for unloading liquefied carbon dioxide includes the steps of: pressurizing the inside of the first tank to transfer the liquefied carbon dioxide in the first tank from the first transfer pipe through the second transfer pipe to the second tank; when the liquid level of the liquefied carbon dioxide in the second tank reaches a predetermined liquid level, transferring the liquefied carbon dioxide in the first tank from the first transfer pipe to the second tank through the third transfer pipe; and sending the liquefied carbon dioxide in the second tank to the outside of the second tank through the unloading pipe.

The float, liquefied carbon dioxide loading method, and liquefied carbon dioxide unloading method disclosed herein can suppress the generation of dry ice in the piping and facilitate loading and unloading operations.

FIG. 1 is a plan view showing a schematic configuration of a ship as a floating body according to each embodiment of the present disclosure. FIG. 2 is a diagram showing a tank, a loading pipe, and a discharge pipe provided in the ship according to the first embodiment of the present disclosure, and is a cross-sectional view taken along the line II-II in FIG. 1. FIG. 11 is a cross-sectional view showing a tank, a loading pipe, and a discharge pipe provided in a ship according to a second embodiment of the present disclosure. 11 is a flowchart showing the steps of a method for loading liquefied carbon dioxide according to a second embodiment of the present disclosure. A cross-sectional view showing the state in which liquefied carbon dioxide is loaded through a second loading pipe in a method for loading liquefied carbon dioxide according to a second embodiment of the present disclosure. A cross-sectional view showing the state in which liquefied carbon dioxide is loaded through a third loading pipe in a method for loading liquefied carbon dioxide according to a second embodiment of the present disclosure. FIG. 11 is a cross-sectional view showing a tank, a loading pipe, and a discharge pipe provided in a ship according to a third embodiment of the present disclosure. FIG. 11 is a cross-sectional view showing a tank, a loading pipe, and a discharge pipe provided in a ship according to a fourth embodiment of the present disclosure. 11 is a flowchart showing the steps of a method for unloading liquefied carbon dioxide according to a fourth embodiment of the present disclosure. A cross-sectional view showing the state in which liquefied carbon dioxide is being transferred through a second loading pipe in a method for unloading liquefied carbon dioxide according to a fourth embodiment of the present disclosure. A cross-sectional view showing the state in which liquefied carbon dioxide is being transferred through a third loading pipe in a method for unloading liquefied carbon dioxide according to a fourth embodiment of the present disclosure.

Hereinafter, a float, a method for loading liquefied carbon dioxide, and a method for unloading liquefied carbon dioxide according to an embodiment of the present disclosure will be described with reference to Figures 1 to 11.
First Embodiment
(Vessel configuration)
As shown in Fig. 1, in the embodiment of the present disclosure, a ship 1, which is a floating body, transports liquefied carbon dioxide. The ship 1 includes at least a hull 2 as a floating body main body, and a tank facility 10A.

(Hull configuration)
The hull 2 has a pair of side walls 3A, 3B, a bottom (not shown), and an upper deck 5, which form the outer hull of the hull. The side walls 3A, 3B have a pair of side wall shells that form the left and right sides, respectively. The bottom (not shown) has a bottom shell that connects the side walls 3A, 3B. The pair of side walls 3A, 3B and the bottom (not shown) form the outer hull of the hull 2 in a U-shape in a cross section perpendicular to the bow-stern direction Da. The upper deck 5 illustrated in this embodiment is a full-length deck exposed to the outside. The hull 2 has a superstructure 7 having a living area formed on the upper deck 5 on the stern 2b side.

A cargo hold 8 is formed inside the hull 2, closer to the bow 2a than the superstructure 7. The cargo hold 8 is recessed toward the bottom of the ship below the upper deck 5, and opens upward.

(Tank equipment configuration)
A plurality of tank facilities 10A are arranged along the bow-stern direction Da in the cargo carrying section 8. In the embodiment of the present disclosure, two tank facilities 10A are arranged at an interval in the bow-stern direction Da.

As shown in FIG. 2 , the tank facility 10A includes at least a tank 11, a loading pipe 20A, and an unloading pipe 30.
In this embodiment, the tank 11 is disposed in the hull 2. The tank 11 is, for example, cylindrical and extends in the horizontal direction. The tank 11 contains liquefied carbon dioxide L therein. The tank body includes a cylindrical portion 12 and an end spherical portion 13. The cylindrical portion 12 extends in the horizontal direction as the longitudinal direction Dx. In this embodiment, the cylindrical portion 12 is formed in a cylindrical shape having a circular cross section perpendicular to the longitudinal direction Dx. The end spherical portions 13 are disposed at both ends of the cylindrical portion 12 in the longitudinal direction Dx. Each end spherical portion 13 is semispherical and closes the openings at both ends of the cylindrical portion 12 in the longitudinal direction Dx. Note that the tank 11 is not limited to being cylindrical, and may be spherical, rectangular, or the like.

The loading pipe 20A loads liquefied carbon dioxide L supplied from outside the ship, such as from a land-based liquefied carbon dioxide supply facility, into the tank 11. The loading pipe 20A includes a first loading pipe 21 and a second loading pipe 22.

The first loading pipe 21 is detachably connected to a supply pipe (not shown) through which liquefied carbon dioxide is supplied from a liquefied carbon dioxide supply facility outside the ship. The first loading pipe 21 is disposed outside the tank 11. In this embodiment, the first loading pipe 21 extends horizontally above the tank 11 in the vertical direction Dv. The first loading pipe 21 has a first inner diameter D1.

One end 22a of the second loading pipe 22 (in other words, the upper end in the vertical direction Dv) is connected to the first loading pipe 21. The second loading pipe 22 penetrates the top of the tank 11 and extends from the outside to the inside of the tank 11. The second loading pipe 22 extends in the vertical direction Dv within the tank 11. The other end 22b of the second loading pipe 22 (in other words, the lower end in the vertical direction Dv) opens downward at the bottom of the tank 11. The second loading pipe 22 has a second inner diameter D2 smaller than the first inner diameter D1. In this embodiment, the second loading pipe 22 has the second inner diameter D2 over its entire length. The second loading pipe 22 may be formed with the second inner diameter D2 only for a certain length on the other end 22b side, and the one end 22a side may be formed with the same first inner diameter D1 as the first loading pipe 21.

The discharge pipe 30 discharges the liquefied carbon dioxide L in the tank 11 outside the ship, such as to a liquefied carbon dioxide supply facility on land. The discharge pipe 30 penetrates the top of the tank 11 from the outside of the tank 11 and extends into the inside of the tank 11. The tip of the discharge pipe 30 is located at the bottom inside the tank 11. A pump 31 is provided at the tip of the discharge pipe 30. The pump 31 sucks in the liquefied carbon dioxide L in the tank 11. The discharge pipe 30 discharges the liquefied carbon dioxide L sucked in by the pump 31 outside the tank 11 (outside the ship).

(Action and Effect)
In the ship 1 as described above, the liquefied carbon dioxide L is loaded into the tank 11 from the first loading pipe 21 through the second loading pipe 22. The second inner diameter D2 of the second loading pipe 22 is smaller than the first inner diameter D1 of the first loading pipe 21. Therefore, the pressure loss ΔP in the second loading pipe 22 is larger than that in the first loading pipe 21.

Here, the pressure P _L of the liquefied carbon dioxide L at the top of the loading pipe 20A is expressed by the following formula (1).
_PL = _PT - ρg (h ₂ - _{h 1} )/1000+ΔP (1)
however,
P _L : Pressure of liquefied carbon dioxide L at the top of the loading pipe 20A (kPaG)
P _T : Pressure of the liquefied carbon dioxide L at the top of the tank 11 (kPaG)
ρ: Liquid density of liquefied carbon dioxide L (kg/m ³ )
g: Gravitational acceleration (m/s ² )
_h2 : Height (m) from the bottom of the tank 11 to the top of the loading pipe 20A
h ₁ : Height from the bottom of the tank 11 to the liquid level of the liquefied carbon dioxide L (m)

According to the above formula (1), the pressure (P _L ) of the liquefied carbon dioxide L at the top of the loading pipe 20A is increased by the amount of the pressure loss ΔP. By increasing the pressure of the liquefied carbon dioxide L at the top of the loading pipe 20A, the pressure of the liquefied carbon dioxide L is prevented from approaching the triple point pressure. This prevents the liquefied carbon dioxide L from solidifying in the loading pipe 20A and producing dry ice. As a result, when storing the liquefied carbon dioxide L in the tank 11, the production of dry ice in the loading pipe 20A is suppressed, making it possible to carry out the loading operation smoothly.

Second Embodiment
Next, a second embodiment of the floating body and the method for loading liquefied carbon dioxide according to the present disclosure will be described. The second embodiment described below differs from the first embodiment only in that it includes a third loading pipe 23. Therefore, the same parts as those in the first embodiment are denoted by the same reference numerals and will not be described again.

As shown in FIG. 3 , the tank facility 10B includes at least a tank 11, a loading pipe 20B, and an unloading pipe 30.
The loading pipe 20B loads the liquefied carbon dioxide L supplied from outside the ship, such as from a liquefied carbon dioxide supply facility on land, into the tank 11. The loading pipe 20B includes a first loading pipe 21, a second loading pipe 22, and a third loading pipe 23.

The first loading pipe 21 is detachably connected to a supply pipe (not shown) through which liquefied carbon dioxide is supplied from a liquefied carbon dioxide supply facility outside the ship. The first loading pipe 21 is disposed outside the tank 11. As in the first embodiment, the first loading pipe 21 extends horizontally above the tank 11 in the vertical direction Dv. The first loading pipe 21 has a first inner diameter D1.

One end 22a of the second loading pipe 22 (in other words, the upper end in the vertical direction Dv) is connected to the first loading pipe 21. The second loading pipe 22 penetrates the top of the tank 11 and extends from the outside to the inside of the tank 11. The second loading pipe 22 extends in the vertical direction Dv within the tank 11. The other end 22b of the second loading pipe 22 (in other words, the upper end in the vertical direction Dv) opens downward at the bottom inside the tank 11. The second loading pipe 22 has a second inner diameter D2 smaller than the first inner diameter D1.

The base end 23a of the third loading pipe 23 (in other words, the upper end in the vertical direction Dv) is connected to the first loading pipe 21. The third loading pipe 23 penetrates the top of the tank 11 and extends from the outside to the inside of the tank 11. The third loading pipe 23 extends in the vertical direction Dv within the tank 11. The tip 23b of the third loading pipe 23 (in other words, the lower end in the vertical direction Dv) opens downward at the bottom of the tank 11. The third loading pipe 23 has a third inner diameter D3 larger than the second inner diameter D2. The third inner diameter D3 may be the same as the first inner diameter D1 of the first loading pipe 21.

The second loading pipe 22 is provided with an on-off valve 24. This on-off valve 24 opens and closes the second loading pipe 22. Similarly, the third loading pipe 23 is provided with an on-off valve 25. The on-off valve 25 opens and closes the third loading pipe 23.

(Procedure for loading liquefied carbon dioxide)
As shown in Figure 4, a method S1 of loading liquefied carbon dioxide according to an embodiment of the present disclosure includes a step S2 of loading liquefied carbon dioxide L through a second loading pipe 22, and a step S3 of loading liquefied carbon dioxide L through a third loading pipe 23.

As shown in FIG. 5, in step S2 of loading liquefied carbon dioxide L through the second loading pipe 22, the on-off valve 24 is opened and the on-off valve 25 is closed. This places the first loading pipe 21 and the second loading pipe 22 in communication. In this state, the liquefied carbon dioxide L supplied from outside the ship is sent from the first loading pipe 21 through the second loading pipe 22 into the tank 11. At this time, the second inner diameter D2 of the second loading pipe 22 is smaller than the first inner diameter D1 of the first loading pipe 21. Therefore, the pressure loss ΔP in the second loading pipe 22 becomes large, and the liquefied carbon dioxide L is loaded while suppressing the generation of dry ice in the loading pipe 20A.

As shown in FIG. 6, when the liquid level of the liquefied carbon dioxide L in the tank 11 reaches a predetermined specified liquid level, the process proceeds to step S3 in which the liquefied carbon dioxide L is loaded through the third loading pipe 23. To do this, the on-off valve 24 is closed and the on-off valve 25 is opened. This places the first loading pipe 21 and the third loading pipe 23 in communication. As described above, when the liquid level of the liquefied carbon dioxide L in the tank 11 rises and reaches the specified liquid level, the pressure difference between the liquefied carbon dioxide L in the tank 11 and the top of the loading pipe 20B becomes smaller. This makes it difficult for the liquefied carbon dioxide L to solidify at the top of the loading pipe 20B.

In step S3, which is carried out in this state, liquefied carbon dioxide L supplied from outside the ship can be sent from the first loading pipe 21 through the third loading pipe 23 into the tank 11. The third inner diameter D3 of the third loading pipe 23 is larger than the second inner diameter D2 of the second loading pipe 22. Therefore, compared to step S2, the flow rate of liquefied carbon dioxide L supplied into the tank 11 through the third loading pipe 23 can be increased.

(Action and Effect)
In the ship 1 and the method S1 for loading liquefied carbon dioxide L of the second embodiment described above, when the liquid level of the liquefied carbon dioxide L in the tank 11 is low, the liquefied carbon dioxide L is loaded into the tank 11 from the first loading pipe 21 through the second loading pipe 22. Since the second inner diameter D2 of the second loading pipe 22 is smaller than the first inner diameter D1 of the first loading pipe 21, the pressure of the liquefied carbon dioxide L at the top of the loading pipe 20B is increased by the pressure loss ΔP occurring in the second loading pipe 22. This prevents the liquefied carbon dioxide L from solidifying in the loading pipe 20B and generating dry ice. As a result, when the liquefied carbon dioxide L is stored in the tank 11, the generation of dry ice in the loading pipe 20B is suppressed, and the loading operation can be performed smoothly.
In addition, after the liquid level of the liquefied carbon dioxide L in the tank 11 rises and reaches a specified liquid level, the liquefied carbon dioxide L is loaded into the tank 11 through the third loading pipe 23. This makes it possible to load the liquefied carbon dioxide L in a short period of time.

Third Embodiment
Next, a third embodiment of the floating body and the method for loading liquefied carbon dioxide according to the present disclosure will be described. In the third embodiment described below, the same parts as those in the first and second embodiments described above are denoted by the same reference numerals, and duplicated explanations will be omitted.
As shown in FIG. 7, the tank facility 10C includes at least a plurality of tanks 11, a loading pipe 20C, an unloading pipe 30, and a transfer pipe 40C.
The loading pipes 20C load the liquefied carbon dioxide L supplied from outside the ship, such as a liquefied carbon dioxide supply facility on land, into the tanks 11. The loading pipes 20C of the third embodiment are provided for each of the multiple tanks 11.

The discharge pipe 30 discharges the liquefied carbon dioxide L in each tank 11 to the outside of the ship, such as to a liquefied carbon dioxide supply facility on land. The discharge pipe 30 penetrates the top of the tank 11 from the outside of the tank 11 and extends into the inside of the tank 11. The tip of the discharge pipe 30 is disposed at the bottom of the tank 11. The tip of the discharge pipe 30 is provided with a pump 31. The pump 31 sucks in the liquefied carbon dioxide L in the tank 11. The discharge pipe 30 discharges the liquefied carbon dioxide L sucked by the pump 31 to the outside of the tank 11 (outside the ship). The discharge pipe 30 of this third embodiment is also provided for each of the multiple tanks 11, similar to the loading pipe 20C. In the following description, a case in which the multiple tanks 11 include two tanks, a first tank 11P and a second tank 11Q, will be described as an example.

The transfer pipe 40C is arranged so as to straddle the first tank 11P and the second tank 11Q. The transfer pipe 40C connects the inside of the first tank 11P to the inside of the second tank 11Q. This transfer pipe 40C makes it possible to transfer the liquefied carbon dioxide L from the first tank 11P to the second tank 11Q. The transfer pipe 40C includes a first transfer pipe 41 and a second transfer pipe 42.

The first transfer pipe 41 is disposed on the first tank 11P side. The first end 41a of the first transfer pipe 41 is inserted into the first tank 11P and opens downward at the bottom of the first tank 11P. The first transfer pipe 41 extends upward from the first end 41a to the outside of the first tank 11P. The middle portion 41b of the first transfer pipe 41, which is disposed outside both the first tank 11P and the second tank 11Q, extends horizontally above the first tank 11P and the second tank 11Q. The first transfer pipe 41 has a first inner diameter D11.

One end 42a of the second transfer pipe 42 is connected to the first transfer pipe 41. The second transfer pipe 42 penetrates the top of the second tank 11Q and extends from the outside to the inside of the second tank 11Q. The second transfer pipe 42 extends in the vertical direction Dv within the second tank 11Q. The other end 42b of the second transfer pipe 42 opens downward at the bottom of the second tank 11Q. The second transfer pipe 42 has a second inner diameter D12 that is smaller than the first inner diameter D11. In this third embodiment, the second transfer pipe 42 has the second inner diameter D12 over its entire length. The second transfer pipe 42 may be formed with the second inner diameter D12 only for a certain length on the other end 42b side, and the one end 42a side may be formed with the same first inner diameter D11 as the first transfer pipe 41.

The transfer pipe 40C is provided with an on-off valve 45. The on-off valve 45 opens and closes the transfer pipe 40C. The on-off valve 45 is normally kept in a closed state.
When the liquefied carbon dioxide L in each tank 11 (first tank 11P, second tank 11Q) is discharged, the pump 31 provided in the discharge pipe 30 is operated in each tank 11. The pump 31 then sucks in the liquefied carbon dioxide L in the tank 11 and sends it out of the ship through the discharge pipe 30.

When the pump 31 of the first tank 11P is unable to perform the required function due to a malfunction or the like, the on-off valve 45 is opened. Then, the first tank 11P and the second tank 11Q are connected through the transfer pipe 40C. In this state, the pressurizing gas Gp (e.g., boil-off gas) in a tank other than the first tank 11P (e.g., the second tank 11Q) is inserted into the first tank 11P through a pressurizing gas pipe (not shown). Then, the pressure of the gas phase in the first tank 11P increases, and the liquefied carbon dioxide L in the first tank 11P is pressurized. As a result, the pressure difference between the pressure of the gas phase in the first tank 11P and the pressure of the gas phase in the second tank 11Q causes the liquefied carbon dioxide L in the first tank 11P to be sent into the second tank 11Q through the transfer pipe 40C (first transfer pipe 41, second transfer pipe 42). The liquefied carbon dioxide L transferred from the first tank 11P to the second tank 11Q is sent out of the ship through the discharge pipe 30 by a pump 31 installed in the discharge pipe 30 of the second tank 11Q.

(Action and Effect)
In the ship 1 as described above, the liquefied carbon dioxide L is transferred from the first tank 11P to the second tank 11Q through the first transfer piping 41 and the second transfer piping 42. The liquefied carbon dioxide L transferred to the second tank 11Q is sent to the outside through the discharge piping 30 of the second tank 11Q. In this way, even if discharge operations cannot be performed through the discharge piping 30 of the first tank 11P, the liquefied carbon dioxide L in the first tank 11P can be discharged to the outside via the second tank 11Q.
Since the second inner diameter D12 of the second transfer pipe 42 is smaller than the first inner diameter D11 of the first transfer pipe 41, the pressure loss ΔP in the second transfer pipe 42 is larger than that in the first transfer pipe 41, and the pressure of the liquefied carbon dioxide L flowing through the transfer pipe 40C can be increased by the pressure loss ΔP. Therefore, the pressure of the liquefied carbon dioxide L at the top of the transfer pipe 40C is increased, and the pressure of the liquefied carbon dioxide L can be prevented from approaching the triple point pressure. This prevents the liquefied carbon dioxide L from solidifying in the transfer pipe 40C to produce dry ice. As a result, even when the liquefied carbon dioxide L is transferred from the first tank 11P to the second tank 11Q by the transfer pipe 40C, the generation of dry ice in the transfer pipe 40C can be suppressed, and the transfer and lifting operations can be performed smoothly.

<Fourth embodiment>
Next, a fourth embodiment of the floating body and the method for unloading liquefied carbon dioxide according to the present disclosure will be described. The fourth embodiment described below differs from the third embodiment only in that it includes a third transfer pipe 43. Therefore, the same parts as those in the third embodiment are denoted by the same reference numerals and will not be described again.

As shown in FIG. 8, the tank facility 10D includes at least a plurality of tanks 11, a plurality of loading pipes 20C, a plurality of unloading pipes 30, and a transfer pipe 40D. Note that in this fourth embodiment, an example will be described in which there are two tanks 11 (a first tank 11P and a second tank 11Q).

The transfer pipe 40D is arranged to span between the first tank 11P and the second tank 11Q. The transfer pipe 40D transfers the liquefied carbon dioxide L from the first tank 11P to the second tank 11Q. The transfer pipe 40D includes a first transfer pipe 41, a second transfer pipe 42, and a third transfer pipe 43.

The first transfer pipe 41 is disposed on the first tank 11P side. The first end 41a of the first transfer pipe 41 is inserted into the first tank 11P and opens downward at the bottom of the first tank 11P. The middle portion 41b of the first transfer pipe 41, which is disposed outside both the first tank 11P and the second tank 11Q, extends horizontally above the first tank 11P and the second tank 11Q. The first transfer pipe 41 has a first inner diameter D11.

One end 42a of the second transfer pipe 42 (in other words, the upper end in the vertical direction Dv) is connected to the first transfer pipe 41. The second transfer pipe 42 passes through the top of the second tank 11Q and extends from the outside to the inside of the second tank 11Q. The second transfer pipe 42 extends in the vertical direction Dv within the second tank 11Q. The other end 42b of the second transfer pipe 42 opens downward at the bottom of the second tank 11Q. The second transfer pipe 42 has a second inner diameter D12 that is smaller than the first inner diameter D11.

The base end 43a of the third transfer pipe 43 (in other words, the upper end in the vertical direction Dv) is connected to the first transfer pipe 41. The third transfer pipe 43 penetrates the top of the second tank 11Q and extends from the outside to the inside of the second tank 11Q. The third transfer pipe 43 extends in the vertical direction Dv within the second tank 11Q. The tip 43b of the third transfer pipe 43 (in other words, the lower end in the vertical direction Dv) opens downward at the bottom of the tank 11. The third transfer pipe 43 has a third inner diameter D13 larger than the second inner diameter D2. The third inner diameter D13 may be the same as the first inner diameter D11 of the first transfer pipe 41.

An on-off valve 46 is provided in the second transfer pipe 42. The on-off valve 46 opens and closes the second transfer pipe 42. An on-off valve 47 is provided in the third transfer pipe 43. The on-off valve 47 opens and closes the third transfer pipe 43. The on-off valves 46, 47 are normally kept in a closed state.
When the liquefied carbon dioxide L in each tank (first tank 11P, second tank 11Q) is discharged, the pump 31 provided in the discharge pipe 30 is operated in each tank 11. The pump 31 then sucks in the liquefied carbon dioxide L in the tank 11 and sends it out of the ship through the discharge pipe 30.

(Procedure for unloading liquefied carbon dioxide)
When the pump 31 of the first tank 11P is unable to perform the required function due to a malfunction or the like, the following liquefied carbon dioxide unloading method S11 is executed.
As shown in Figure 9, a method S11 for unloading liquefied carbon dioxide according to an embodiment of the present disclosure includes a step S12 of transporting liquefied carbon dioxide L through a second transport piping 42, a step S13 of transporting the liquefied carbon dioxide L through a third transport piping 43, and a step S14 of sending the liquefied carbon dioxide L to the outside.

10, in step S12 of transferring the liquefied carbon dioxide L through the second transfer pipe 42, the on-off valve 46 is opened and the on-off valve 47 is closed. As a result, the first transfer pipe 41 and the second transfer pipe 42 are in a state of communication. In this state, the boil-off gas in another tank (for example, the second tank 11Q) other than the first tank 11P is introduced into the first tank 11P through a pressurizing gas pipe (not shown) as the pressurizing gas Gp. Then, the pressure of the gas phase in the first tank 11P increases, and a pressure difference occurs between the pressure of the gas phase in the first tank 11P and the pressure of the gas phase in the second tank 11Q. As a result, the liquefied carbon dioxide L in the first tank 11P is sent into the second tank 11Q through the first transfer pipe 41 and the second transfer pipe 42. At this time, the second inner diameter D2 of the second transfer pipe 42 is smaller than the first inner diameter D1 of the first transfer pipe 41. As a result, the pressure loss ΔP in the second transfer pipe 42 increases, and the liquefied carbon dioxide L is loaded while preventing the generation of dry ice in the transfer pipe 40D.

11, when the liquid level of the liquefied carbon dioxide L in the second tank 11Q reaches a predetermined specified liquid level, the process proceeds to step S13 of transferring the liquefied carbon dioxide L through the third transfer piping 43. For this, the on-off valve 46 is closed and the on-off valve 47 is opened. As a result, the first transfer piping 41 and the third transfer piping 43 are in a state of communication with each other.
As described above, when the liquid level of the liquefied carbon dioxide L in the tank 11 rises and reaches the specified liquid level, the pressure difference between the liquefied carbon dioxide L in the second tank 11Q and the top of the transfer pipe 40D becomes small. This makes it difficult for the liquefied carbon dioxide L to solidify at the top of the transfer pipe 40D.
In this state, step S13 is carried out. In this step S13, the pressurizing gas Gp is used in the same manner as described above, and the liquefied carbon dioxide L in the first tank 11P is transferred from the first transfer pipe 41 to the second tank 11Q through the third transfer pipe 43. At this time, the third inner diameter D3 of the third transfer pipe 43 is larger than the second inner diameter D2 of the second transfer pipe 42. Therefore, compared to step S12, the flow rate of the liquefied carbon dioxide L supplied into the second tank 11Q through the third transfer pipe 43 can be increased.

In step S14 of sending the liquefied carbon dioxide L to the outside of the second tank 11Q, the liquefied carbon dioxide L in the second tank 11Q is sent to the outside of the tank 11 via the lift pipe 30. Such step S14 may be carried out in parallel with the above steps S12 and S13.

(Action and Effect)
In the ship 1 and the method S11 for unloading liquefied carbon dioxide L as described above, when the liquid level of the liquefied carbon dioxide L in the tank 11 is low, the liquefied carbon dioxide L is transferred from the first tank 11P to the second tank 11Q through the second transfer pipe 42, thereby suppressing the solidification of the liquefied carbon dioxide L in the transfer pipe 40D and the generation of dry ice. In addition, when the liquid level of the liquefied carbon dioxide L in the second tank 11Q rises and the pressure difference between the liquefied carbon dioxide L in the second tank 11Q and the top of the transfer pipe 40D becomes small, and the liquefied carbon dioxide L is difficult to solidify at the top of the pipe, the liquefied carbon dioxide L is transferred from the first tank 11P to the second tank 11Q through the third transfer pipe 43. This allows the transfer of the liquefied carbon dioxide L to be performed in a short time. As a result, even when the liquefied carbon dioxide L is transferred from the first tank 11P to the second tank 11Q through the transfer pipe 40D, the generation of dry ice in the transfer pipe 40D can be suppressed, and the transfer and unloading operations can be performed smoothly.

Other Embodiments
Although the embodiments of the present disclosure have been described in detail above with reference to the drawings, the specific configuration is not limited to this embodiment, and design changes and the like that do not deviate from the gist of the present disclosure are also included.
In each of the above embodiments, the vessel is configured to include two tanks 11, but the number and arrangement of the tanks 11 are not limited to this. Three or more tanks 11 may be provided. In addition, in each of the above embodiments, the vessel is configured to include a plurality of tanks 11 arranged in the bow-stern direction Da, but the tanks 11 may be arranged in the width direction of the vessel (in other words, the port and starboard directions).

In addition, in each of the above embodiments, a ship 1 is given as an example of a floating body, but this is not limited thereto. The floating body may be an offshore floating facility that does not have a propulsion mechanism.

<Additional Notes>
The floating body 1, the method of loading liquefied carbon dioxide L, and the method of unloading liquefied carbon dioxide L described in each embodiment can be understood, for example, as follows.

(1) A float 1 in a first aspect comprises a float body 2, a tank 11 arranged on the float body 2 and capable of storing liquefied carbon dioxide L, and loading pipes 20A, 20B for discharging liquefied carbon dioxide L supplied from the outside into the tank 11, wherein the loading pipes 20A, 20B comprise a first loading pipe 21 arranged outside the tank 11 and having a first inner diameter D1, and a second loading pipe 22 having one end 22a connected to the first loading pipe 21 and the other end 22b opening inside the tank 11 and having a second inner diameter D2 smaller than the first inner diameter D1.
Examples of the floating body 1 include a ship and an offshore floating facility. Examples of the floating body main body 2 include a hull and a floating body main body 2 of an offshore floating facility.

In this floating body 1, liquefied carbon dioxide L is loaded into the tank 11 from the first loading pipe 21 through the second loading pipe 22. The second inner diameter D2 of the second loading pipe 22 is smaller than the first inner diameter D1 of the first loading pipe 21. Therefore, the pressure loss ΔP in the second loading pipe 22 is larger than that in the first loading pipe 21. As a result, the pressure of the liquefied carbon dioxide L flowing through the loading pipes 20A and 20B is increased by the pressure loss ΔP. By increasing the pressure of the liquefied carbon dioxide L at the top of the loading pipes 20A and 20B, the pressure of the liquefied carbon dioxide L is prevented from approaching the triple point pressure. This prevents the liquefied carbon dioxide L from solidifying in the loading pipes 20A and 20B to produce dry ice. As a result, when liquefied carbon dioxide L is stored in the tank 11, the generation of dry ice in the loading pipes 20A and 20B is suppressed, making it possible to perform the loading operation smoothly.

(2) The float 1 according to the second aspect is the float 1 of (1), and the loading pipe 20B further includes a third loading pipe 23 whose base end 23a is connected to the first loading pipe 21, whose tip 23b opens inside the tank 11, and whose third inner diameter D3 is larger than the second inner diameter D2.

As a result, if the liquefied carbon dioxide L is loaded into the tank 11 through the third loading pipe 23, which has a third inner diameter D3 larger than the second loading pipe 22, the loading of the liquefied carbon dioxide L can be completed in a short period of time.

(3) The float 1 according to the third aspect comprises a float body 2, a plurality of tanks 11 arranged on the float body 2 and capable of storing liquefied carbon dioxide L, a lifting pipe 30 provided in each of the plurality of tanks 11 for sending the liquefied carbon dioxide L in the tank 11 to the outside of the float body 2, and transfer pipes 40C, 40D arranged to straddle between a first tank 11P and a second tank 11Q constituting the plurality of tanks 11 and connecting the inside of the first tank 11P to the inside of the second tank 11Q. The transfer pipes 40C, 40D are arranged on the first tank 11P side and comprise a first transfer pipe 41 having a first inner diameter D11, and a second transfer pipe 42 having one end 42a connected to the first transfer pipe 41 and the other end 42b opening in the second tank 11Q and having a second inner diameter D12 smaller than the first inner diameter D11.

This allows the liquefied carbon dioxide L to be transferred from the first tank 11P to the second tank 11Q through the transfer piping 40C, 40D. The liquefied carbon dioxide L transferred to the second tank 11Q is sent to the outside through the discharge piping 30 of the second tank 11Q. In this way, even if discharge work cannot be performed through the discharge piping 30 of the first tank 11P, the liquefied carbon dioxide L in the first tank 11P can be discharged to the outside via the second tank 11Q.
The second inner diameter D12 of the second transfer pipe 42 is smaller than the first inner diameter D11 of the first transfer pipe 41. Therefore, the pressure loss ΔP in the second transfer pipe 42 is larger than that in the first transfer pipe 41. As a result, the pressure of the liquefied carbon dioxide L flowing through the transfer pipes 40C and 40D is increased by the pressure loss ΔP. By increasing the pressure of the liquefied carbon dioxide L at the top of the transfer pipes 40C and 40D, the pressure of the liquefied carbon dioxide L is prevented from approaching the triple point pressure. This prevents the liquefied carbon dioxide L from solidifying in the transfer pipes 40C and 40D to produce dry ice. As a result, when the liquefied carbon dioxide L is stored in the tank 11, the generation of dry ice in the transfer pipes 40C and 40D is suppressed, and the transfer and lifting operations can be performed smoothly.

(4) The float 1 according to the fourth aspect is the float 1 according to (3), and the transfer pipe 40D further includes a third transfer pipe 43 whose base end 43a is connected to the first transfer pipe 41, whose tip 43b opens into the second tank 11Q, and whose third inner diameter D13 is larger than the second inner diameter D12.

As a result, by transporting the liquefied carbon dioxide L through the third transport pipe 43 having a third inner diameter D13 larger than that of the second transport pipe 42, the transport of the liquefied carbon dioxide L can be completed in a short period of time.

(5) The method S1 for loading liquefied carbon dioxide L according to the fifth aspect is a method S1 for loading liquefied carbon dioxide L in the floating body 1 of (2), and includes a step S2 of loading liquefied carbon dioxide L from the first loading pipe 21 into the tank 11 through the second loading pipe 22, and a step S3 of loading liquefied carbon dioxide L from the first loading pipe 21 into the tank 11 through the third loading pipe 23 when the liquid level of the liquefied carbon dioxide L in the tank 11 reaches a predetermined liquid level.

As a result, when the liquid level of liquefied carbon dioxide L in the tank 11 is low, the liquefied carbon dioxide L is loaded into the tank 11 through the first loading pipe 21, thereby preventing the liquefied carbon dioxide L from solidifying in the loading pipe 20B and generating dry ice. Also, when the liquid level of liquefied carbon dioxide L in the tank 11 rises and the pressure difference between the liquefied carbon dioxide L in the tank 11 and the top of the loading pipe 20B becomes small, making it difficult for the liquefied carbon dioxide L to solidify at the top of the pipe, the liquefied carbon dioxide L is loaded into the tank 11 through the third loading pipe 23. This allows the loading of liquefied carbon dioxide L to be completed in a short period of time.

(6) The method S11 for unloading liquefied carbon dioxide L according to the sixth aspect is the method S11 for unloading liquefied carbon dioxide L in the floating body 1 of (4), and includes a step S12 of pressurizing the first tank 11P to transfer the liquefied carbon dioxide L in the first tank 11P from the first transfer pipe 41 through the second transfer pipe 42 to the second tank 11Q, a step S13 of transferring the liquefied carbon dioxide L in the first tank 11P from the first transfer pipe 41 through the third transfer pipe 43 to the second tank 11Q when the liquid level of the liquefied carbon dioxide L in the second tank 11Q reaches a predetermined liquid level, and a step S14 of sending the liquefied carbon dioxide L in the second tank 11Q to the outside of the second tank 11Q through the unloading pipe 30.

As a result, when the liquid level of the liquefied carbon dioxide L in the second tank 11Q is low, the liquefied carbon dioxide L is transferred from the first tank 11P to the second tank 11Q through the second transfer pipe 42, thereby preventing the liquefied carbon dioxide L from solidifying in the transfer pipe 40D and generating dry ice. In addition, when the liquid level of the liquefied carbon dioxide L in the second tank 11Q rises and the pressure difference between the liquefied carbon dioxide L in the second tank 11Q and the top of the transfer pipe 40D becomes small, making it difficult for the liquefied carbon dioxide L to solidify at the top of the pipe, the liquefied carbon dioxide L is transferred from the first tank 11P to the second tank 11Q through the third transfer pipe 43. This allows the transfer of the liquefied carbon dioxide L to be completed in a short time.

1... Ship (floating body)
2...Hull (floating body)
2a...bow 2b...stern 3A, 3B...ship side 5...upper deck 7...superstructure 8...cargo carrying area 10A to 10D...tank equipment 11...tank 11P...first tank 11Q...second tank 12...cylindrical section 13...end spherical section 20A to 20C...loading pipe 21...first loading pipe 22...second loading pipe 22a...one end 22b...other end 23...third loading pipe 23a...base end 23b...tip 24, 25...opening/closing valve 30...unloading pipe 31...pump 40C, 40D...transfer pipe 41...first transfer pipe 41a...first end 41b...middle section 42...second transfer pipe 42a...one end 42b...other end 43...third transfer pipe 43a...base end 43b...tip 45 to 47...opening/closing valve Gp...pressurizing gas L...liquefied carbon dioxide

Claims (8)

A floating body;
A tank arranged on the floating body and capable of storing liquefied carbon dioxide;
a loading pipe for discharging liquefied carbon dioxide supplied from an outside into the tank;
The loading pipe is
a first loading pipe disposed outside the tank, extending horizontally above the tank, the first loading pipe having a first inner diameter;
a second loading pipe having one end connected to the first loading pipe and extending from the outside to the inside of the tank, extending in a vertical direction within the tank, and having a second inner diameter smaller than the first inner diameter, the other end being a lower end in the vertical direction and opening within the tank;
A floating body comprising: The loading pipe is
The floating body according to claim 1 , further comprising: a third loading pipe having a base end connected to the first loading pipe, a tip end opening within the tank, and a third inner diameter larger than the second inner diameter. A floating body;
A plurality of tanks arranged on the floating body and capable of storing liquefied carbon dioxide;
A lifting pipe provided in each of the plurality of tanks for sending the liquefied carbon dioxide in the tank to the outside of the floating body;
a transfer pipe disposed between a first tank and a second tank of the plurality of tanks, the transfer pipe connecting an inside of the first tank and an inside of the second tank;
The transfer piping includes:
a first transfer pipe disposed on the first tank side and having a first inner diameter;
a second transfer pipe having one end connected to the first transfer pipe and the other end opening into the second tank, the second transfer pipe having a second inner diameter smaller than the first inner diameter;
Equipped with
the first transfer pipe is disposed outside both the first tank and the second tank and has an intermediate portion extending horizontally above the first tank and the second tank;
The second transfer piping extends from the outside to the inside of the second tank and extends in the vertical direction within the second tank , with the lower end of the second transfer piping opening within the second tank as the other end . The transfer piping includes:
The floating body according to claim 3 , further comprising a third transfer pipe having a base end connected to the first transfer pipe, a tip end opening within the second tank, and a third inner diameter larger than the second inner diameter. A method for loading liquefied carbon dioxide into a floating body according to claim 2, comprising the steps of:
Loading liquefied carbon dioxide into the tank through the first loading pipe and the second loading pipe;
When the liquid level of the liquefied carbon dioxide in the tank reaches a predetermined liquid level, loading the liquefied carbon dioxide into the tank from the first loading pipe through the third loading pipe. A method for unloading liquefied carbon dioxide in a floating body according to claim 4, comprising the steps of:
A step of pressurizing the first tank to transfer liquefied carbon dioxide in the first tank from the first transfer pipe through the second transfer pipe into the second tank;
When the liquid level of the liquefied carbon dioxide in the second tank reaches a predetermined liquid level, the liquefied carbon dioxide in the first tank is transferred from the first transfer pipe to the second tank through the third transfer pipe;
and sending the liquefied carbon dioxide in the second tank to the outside of the second tank through the lifting piping. A floating body;
A tank arranged on the floating body and capable of storing liquefied carbon dioxide;
a loading pipe for discharging liquefied carbon dioxide supplied from an outside into the tank;
The loading pipe is
a first loading pipe disposed outside the tank, the first loading pipe having a first inner diameter;
a second loading pipe having one end connected to the first loading pipe and the other end opening into the tank and having a second inner diameter smaller than the first inner diameter;
Equipped with
The loading pipe is
The float further comprises a third loading pipe having a base end connected to the first loading pipe, a tip end opening within the tank, and a third inner diameter larger than the second inner diameter. A floating body;
A plurality of tanks arranged on the floating body and capable of storing liquefied carbon dioxide;
A lifting pipe provided in each of the plurality of tanks for sending the liquefied carbon dioxide in the tank to the outside of the floating body;
a transfer pipe disposed between a first tank and a second tank of the plurality of tanks, the transfer pipe connecting an inside of the first tank and an inside of the second tank;
The transfer piping includes:
a first transfer pipe disposed on the first tank side and having a first inner diameter;
a second transfer pipe having one end connected to the first transfer pipe and the other end opening into the second tank, the second transfer pipe having a second inner diameter smaller than the first inner diameter;
Equipped with
The transfer piping includes:
The float further comprises a third transfer pipe having a base end connected to the first transfer pipe, a tip end opening within the second tank, and a third inner diameter larger than the second inner diameter.

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