Technical Field
[0001] The present disclosure relates to a method for transferring liquefied carbon dioxide,
and a floating structure.
Background Art
[0003] For example, in PTL 1, a configuration including a transfer device (natural gas transfer
device) for transferring liquefied gas from a ship (import ship) provided with a tank
for storing a liquefied gas (liquefied natural gas (LNG)) to a facility (import terminal)
on land is disclosed. In such a configuration, the ship moored at the facility on
land communicates fluidly with the facility and transfers the liquefied gas in the
tank to the storage tank on land.
Citation List
Patent Literature
Summary of Invention
Technical Problem
[0005] Incidentally, when the liquefied gas is loaded into the tank from an external facility
such as a facility on land or when the liquefied gas in the tank is unloaded to the
external facility, the pipes such as the loading pipe or the unloading pipe provided
in the tank are connected to the external facility via a connection pipe. However,
when connecting the connection pipe to the pipe, there is a possibility that air (atmosphere)
intrudes the inside of the pipe. Then, in a case where the liquefied carbon dioxide
is accommodated in the tank, when air intrusion into the pipe occurs, the moisture
contained in the air reacts with the carbon dioxide, and carbonic acid or hydrate
is formed. When carbonic acid or hydrate is formed in this manner, there is a possibility
that corrosion occurs inside the pipe or the tank.
[0006] Therefore, after the connection pipe is connected to the pipe of the tank, the connection
pipe is filled with carbon dioxide gas. As a result, direct contact of the moisture
contained in the air with the liquefied carbon dioxide is suppressed. However, also
in this case, when the carbon dioxide gas is filled, there is a possibility that the
moisture contained in the air in the connection pipe reacts with the carbon dioxide,
resulting in corrosion inside the tank or the pipe.
[0007] The present disclosure has been made to solve the above problems, and an object thereof
is to provide a method for transferring liquefied carbon dioxide and a floating structure
that can suppress the reaction between carbon dioxide and moisture when the liquefied
carbon dioxide is transferred, and suppress occurrence of corrosion of the inside
of the tank or the pipe.
Solution to Problem
[0008] In order to solve the above problems, a method for transferring liquefied carbon
dioxide according to the present disclosure includes a step of connecting a connection
pipe, a step of replacing with a replacement gas, a step of replacing with a carbon
dioxide gas, and a step of transferring liquefied carbon dioxide. In the step of connecting
the connection pipe, the connection pipe is connected to a pipe communicating with
an inside of a tank provided in a floating structure. The connection pipe is for connection
to an external facility disposed outside the floating structure, to the pipe. In the
step of replacing with the replacement gas, the replacement gas is fed into the connection
pipe and the pipe, and the gas inside the connection pipe and the pipe is replaced
with the replacement gas. The moisture content of the replacement gas is adjusted
to be equal to or less than a predetermined upper limit value. In the step of replacing
with the carbon dioxide gas, the replacement gas is replaced with the carbon dioxide
gas on the inside of the connection pipe and the pipe. In the step of transferring
the liquefied carbon dioxide, the liquefied carbon dioxide is transferred between
the external facility and the tank through the connection pipe and the pipe.
[0009] The floating structure according to the present disclosure includes a floating main
structure, a tank, a pipe, a replacement gas supply unit, and a carbon dioxide supply
unit. The tank is disposed in the floating main structure. The tank is capable of
storing liquefied carbon dioxide. The pipe communicates with an inside of the tank.
The pipe is connectable to a connection pipe for supplying liquefied carbon dioxide
between an external facility and the tank. The replacement gas supply unit feeds a
replacement gas into the pipe and the connection pipe in a case where the connection
pipe is connected to the pipe. A moisture content of the replacement gas is adjusted
to be equal to or less than a predetermined upper limit value. The carbon dioxide
supply unit feeds a carbon dioxide gas into the pipe and the connection pipe.
Advantageous Effects of Invention
[0010] According to the method for transferring liquefied carbon dioxide and the floating
structure according to the present disclosure, it is possible to suppress the reaction
between the carbon dioxide and the moisture when the liquefied carbon dioxide is transferred,
and to suppress the occurrence of corrosion inside the tank or the pipe.
Brief Description of Drawings
[0011]
Fig. 1 is a plan view showing a schematic configuration of a ship as a floating structure
according to an embodiment of the present disclosure.
Fig. 2 is a view showing a tank and a pipe provided in the ship according to the embodiment
of the present disclosure, and is a sectional view taken along line I-I of Fig. 1.
Fig. 3 is a view showing the tank and the pipe provided in the ship according to the
embodiment of the present disclosure, and is a sectional view taken along line II-II
of Fig. 1.
Fig. 4 is a diagram showing an external facility connected to the ship according to
the embodiment of the present disclosure by a connection pipe.
Fig. 5 is a flowchart showing a procedure of a method for transferring liquefied carbon
dioxide according to the embodiment of the present disclosure.
Fig. 6 is a view showing a step of connecting the connection pipe in the method for
transferring liquefied carbon dioxide according to the embodiment of the present disclosure.
Fig. 7 is a view showing a step of replacing with a replacement gas in the method
for transferring liquefied carbon dioxide according to the embodiment of the present
disclosure.
Fig. 8 is a view showing a step of replacing with a carbon dioxide gas in the method
for transferring liquefied carbon dioxide according to the embodiment of the present
disclosure.
Fig. 9 is a view showing a step of transferring liquefied carbon dioxide in the method
for transferring liquefied carbon dioxide according to the embodiment of the present
disclosure.
Description of Embodiments
[0012] Hereinafter, a floating structure and a method for transferring liquefied carbon
dioxide according to embodiments of the present disclosure will be described with
reference to Figs. 1 to 9.
(Configuration of Ship)
[0013] As shown in Figs. 1 and 2, in the embodiment of the present disclosure, a ship 1
which is a floating structure carries liquefied carbon dioxide. The ship 1 includes
at least a hull 2 as a floating main structure, a tank facility 10, a replacement
gas supply unit 20 (refer to Fig. 2), and a carbon dioxide supply unit 30 (refer to
Fig. 2).
(Configuration of Hull)
[0014] The hull 2 has a pair of sides 3A and 3B, a bottom 4 (refer to Fig. 2), and an upper
deck 5, which form an outer shell thereof. The sides 3A and 3B each have a pair of
side shell platings which form the left and right sides on both sides in a ship width
direction Dw. The bottom 4 is disposed below in a vertical direction Dv and has a
bottom shell plating connecting these sides 3A and 3B to each other. As shown in Fig.
2, due to the pair of sides 3A and 3B and the bottom 4, the outer shell of the hull
2 has a U-shape in a cross section orthogonal to a stem-stern direction Da. The upper
deck 5 shown in this embodiment is a continuous deck exposed to the outside. In the
hull 2, a superstructure 7 having an accommodation space is formed on the upper deck
5 on a stern 2b side.
[0015] Inside the hull 2, a cargo tank storage compartment (hold) 8 is formed on a stem
2a side of the superstructure 7. The cargo tank storage compartment 8 is recessed
toward the bottom below the upper deck 5, and is open upward.
(Configuration of Tank Facility)
[0016] A plurality of tank facilities 10 are disposed in the cargo tank storage compartment
8 along the stem-stern direction Da. In the embodiment of the present disclosure,
two tank facilities 10 are disposed at intervals in the stem-stern direction Da.
[0017] As shown in Figs. 2 and 3, the tank facility 10 includes at least a tank 11 and a
pipe 12.
[0018] In this embodiment, the tank 11 is disposed on the hull 2. The tank 11 has, for example,
a cylindrical shape extending in the horizontal direction. In this embodiment, the
tank 11 is disposed in the long axis direction along the stem-stern direction Da.
The tank 11 accommodates a liquefied carbon dioxide L inside thereof. The tank 11
is not limited to a cylindrical shape, and the tank 11 may have a spherical shape,
a square shape, or the like.
[0019] The pipe 12 includes a loading pipe 13 and an unloading pipe 14. That is, as the
pipe 12 of the tank facility 10, there are two types of pipes, the loading pipe 13
and the unloading pipe 14.
[0020] As shown in Fig. 3, the loading pipe 13 forms a pipe line for loading the liquefied
carbon dioxide L supplied from an external facility 100 (refer to Fig. 4) on the outside
of the ship, such as an on-land liquefied carbon dioxide supply facility, into the
tank 11. A part of the loading pipe 13 on a side close to one end 13a thereof penetrates
the top of the tank 11 and extends from the outside to the inside of the tank 11.
A part of the loading pipe 13 on a side close to the one end 13a extends in the vertical
direction Dv inside the tank 11. The one end 13a of the loading pipe 13 opens in the
tank 11 at the lower portion of the tank 11.
[0021] The rest of the loading pipe 13, that is, a part on a side close to the other end
13b is disposed outside the tank 11. As shown in Fig. 2, the other end 13b of the
loading pipe 13 is provided with a connection portion 13j connected to the outside
of the ship. The connection portion 13j has, for example, a flange or the like. The
connection portion 13j is disposed toward one (for example, the side 3A) of the sides
3A and 3B. The opening of a connection portion 14j is normally blocked by a lid (not
shown). By removing the lid (not shown) of the connection portion 13j, it is possible
to connect the end portion of the connection pipe 50 for connection to a facility
side tank 101 of the external facility 100 in place of the lid (not shown).
[0022] The unloading pipe 14 delivers the liquefied carbon dioxide L in the tank 11 to the
external facility 100 on the outside of the ship. A part of the unloading pipe 14
on a side close to one end 14a penetrates the top of the tank 11 from the outside
of the tank 11 and extends to the inside of the tank 11. The one end 14a of the unloading
pipe 14 is disposed in the lower portion inside the tank 11. A pump (not shown) is
provided at the one end 14a of the unloading pipe 14. The pump (not shown) sucks the
liquefied carbon dioxide L in the tank 11 and delivers the liquefied carbon dioxide
L to the unloading pipe 14. The unloading pipe 14 guides the liquefied carbon dioxide
L delivered from the pump to the outside of the tank 11 (the outside of the ship).
[0023] A part of the unloading pipe 14 on a side close to the other end 14b, which is the
rest of the unloading pipe 14, is disposed outside the tank 11. As shown in Fig. 2,
the other end 14b of the unloading pipe 14 is provided with the connection portion
14j to the outside of the ship. The connection portion 14j has, for example, a flange
or the like, and is disposed toward one (for example, the side 3A) of the sides 3A
and 3B. The opening of a connection portion 14j is normally blocked by a lid (not
shown). By removing the lid (not shown) of the connection portion 14j, it is possible
to connect the end portion of the connection pipe 50 for connection to a facility
side tank 101 of the external facility 100 in place of the lid (not shown).
[0024] As shown in Fig. 4, in a case where the liquefied carbon dioxide L is loaded into
the tank 11 from the external facility 100, the connection pipe 50 connects and allows
a facility side pipe 102 provided in the facility side tank 101 of the external facility
100 and the connection portion 13j of the loading pipe 13 to communicate with each
other. In addition, in a case where the liquefied carbon dioxide L is unloaded from
the tank 11 to the external facility 100, the connection pipe 50 connects and allows
the facility side pipe 102 provided in the facility side tank 101 of the external
facility 100 and the connection portion 14j of the unloading pipe 14 to communicate
with each other. In the following description, except for the case where the loading
pipe 13 and the unloading pipe 14 are distinguished, the loading pipe 13 and the unloading
pipe 14 are simply referred to as pipes 12, and the connection portions 13j and 14j
are simply referred to as connection portions 12j.
[0025] Opening-closing valves 15 and 105 are provided on the pipe 12 and the facility side
pipe 102 on the external facility 100 side, respectively. The opening-closing valve
15 opens and closes a flow channel in the pipe 12. The opening-closing valve 105 opens
and closes a flow channel in the facility side pipe 102. In addition, an opening valve
106 is provided in the facility side pipe 102. When the opening valve 106 is opened,
the flow channel inside the facility side pipe 102 and the outside communicate with
each other. When the opening-closing valves 15 and 105 are closed in a state where
the facility side pipe 102 and the pipe 12 are connected to each other by the connection
pipe 50, the inside of the pipe 12, the connection pipe 50, and the facility side
pipe 102 positioned between the opening-closing valve 15 and the opening-closing valve
105 is not communicated with the facility side tank 101 or the tank 11. Here, the
outside to which the flow channel in the facility side pipe 102 is communicated is
not limited to the atmosphere. For example, a container such as a tank capable of
storing the gas discharged through the opening valve 106 may be adopted.
[0026] As shown in Fig. 2, the replacement gas supply unit 20 feeds a replacement gas Ga
into the pipe 12 and the connection pipe 50 in a state where the connection pipe 50
for connection to the external facility 100 is connected to the pipe 12. As the replacement
gas Ga, a gas that does not cause a chemical reaction with carbon dioxide is used.
The moisture content of the replacement gas Ga is adjusted to be equal to or less
than a predetermined upper limit value. As the replacement gas Ga, air having the
moisture content adjusted to be equal to or less than a predetermined upper limit
value (so-called dry air) or an inert gas such as nitrogen or argon can be used. In
this embodiment, dry air is used as the replacement gas Ga. The replacement gas supply
unit 20 includes an air dryer 21. The air dryer 21 removes moisture from the atmosphere
taken in from the outside to form dry air having the moisture content adjusted to
be equal to or less than a predetermined upper limit value, for example, a dew point
temperature of -40°C. The air dryer 21 is connected to the pipe 12 via a replacement
gas supply pipe 22. An opening-closing valve 23 is provided in the replacement gas
supply pipe 22. The dry air formed by the air dryer 21 is fed to the inside of the
pipe 12, the connection pipe 50, and the facility side pipe 102 through the replacement
gas supply pipe 22 by opening the opening-closing valve 23. The upper limit value
of the moisture content in the dry air may be any value as long as the moisture in
the pipe can be efficiently removed, and can be obtained in advance by an experiment
or the like.
[0027] As shown in Figs. 2 and 4, the carbon dioxide supply unit 30 feeds a carbon dioxide
gas Gc into the pipe 12, the connection pipe 50, and the facility side pipe 102 in
a state where the connection pipe 50 for connection to the external facility 100 is
connected to the pipe 12. In this embodiment, the carbon dioxide supply unit 30 uses
the boil-off gas formed by the vaporization of the liquefied carbon dioxide L in the
tank 11 as the carbon dioxide gas Gc. The carbon dioxide supply unit 30 includes a
boil-off gas supply pipe 31 (refer to Figs. 2 and 3). The boil-off gas supply pipe
31 allows the gas phase in the upper portion in the tank 11 and the pipe 12 to communicate
with each other. The carbon dioxide supply unit 30 feeds the boil-off gas from the
tank 11 to the inside of the connection pipe 50 and the facility side pipe 102 through
the pipe 12.
(Procedure of Method for Transferring Liquefied Carbon Dioxide)
[0028] As shown in Fig. 5, a method S10 for transferring the liquefied carbon dioxide L
according to this embodiment includes a step S11 of connecting the connection pipe
50, a step S12 of replacing with the replacement gas Ga, a step S13 of replacing with
the carbon dioxide gas Gc, and a step S14 of transferring the liquefied carbon dioxide
L.
[0029] In the step S11 of connecting the connection pipe 50, as shown in Fig. 6, one end
of the connection pipe 50 for connection to the external facility 100 is connected
to the pipe 12. Further, the other end of the connection pipe 50 is connected to the
facility side pipe 102 of the external facility 100. At this time, the opening-closing
valves 15, 23, and 105, and the opening valve 106 are kept in the closed state. In
this state, air is contained in the pipe 12, the connection pipe 50, and the facility
side pipe 102 positioned between the opening-closing valve 15 and the opening-closing
valve 105.
[0030] In the step S12 of replacing with the replacement gas Ga, as shown in Fig. 7, the
replacement gas Ga is fed into the inside of the connection pipe 50 by the replacement
gas supply unit 20. To this end, the air dryer 21 is operated, and the opening-closing
valves 15 and 105 are closed, and the opening-closing valves 23 and the opening valves
106 are opened. By removing the moisture in the air (atmosphere) taken in from the
outside by the air dryer 21, dry air having the moisture content adjusted to be equal
to or less than a predetermined upper limit value is formed, and the dry air becomes
the replacement gas Ga. The replacement gas Ga is supplied to the connection portion
12j of the pipe 12 through the replacement gas supply pipe 22. The supplied replacement
gas Ga flows from the pipe 12 to the connection pipe 50 and the facility side pipe
102, and sequentially pushes the air inside the pipe 12, the connection pipe 50, and
the facility side pipe 102 to the outside from the opening valve 106. The dew point
of the air discharged from the opening valve 106 is measured, and the replacement
gas Ga is continuously fed until the dew point falls within the preset allowable value
range. When the measured dew point falls within the allowable value range, the feeding
of the replacement gas Ga by the replacement gas supply unit 20 is stopped, and the
opening valve 106 and the opening-closing valve 23 are closed. As a result, the inside
of the pipe 12, the connection pipe 50, and the facility side pipe 102 between the
opening-closing valves 15 and 105 is replaced with the replacement gas Ga.
[0031] In the step S13 of replacing with the carbon dioxide gas Gc, the inside of the connection
pipe 50 is replaced with the carbon dioxide gas Gc from the replacement gas Ga. To
this end, as shown in Fig. 8, the opening-closing valves 15 and 105 are opened, and
the opening valve 106 and the opening-closing valve 23 are closed. In this state,
the boil-off gas of the tank 11 is fed as the carbon dioxide gas Gc to the inside
of the connection pipe 50 and the facility side pipe 102 through the carbon dioxide
supply unit 30 and the pipe 12. As a result, the replacement gas Ga (dry air) inside
the pipe 12, the connection pipe 50, and the facility side pipe 102 is sequentially
pushed out to the external facility 100 side. On the external facility 100 side, the
carbon dioxide concentration of the air-fuel mixture of the replacement gas Ga and
the carbon dioxide gas Gc extruded from the connection pipe 50 side is measured. When
the measured carbon dioxide concentration falls within the preset concentration range,
the carbon dioxide supply unit 30 stops the supply of the carbon dioxide gas Gc.
[0032] In the step S14 of transferring the liquefied carbon dioxide L, as shown in Fig.
9, the liquefied carbon dioxide L is transferred between the external facility 100
and the tank 11 through the connection pipe 50 and the pipe 12. For example, in a
case where the liquefied carbon dioxide L is loaded into the tank 11 from the external
facility 100, the liquefied carbon dioxide L is fed into the tank 11 from the facility
side tank 101 of the external facility 100 through the facility side pipe 102, the
connection pipe 50, and the pipe 12 (loading pipe 13).
[0033] Further, in a case where the liquefied carbon dioxide L is unloaded from the inside
of the tank 11 to the external facility 100, the liquefied carbon dioxide L is fed
into the facility side tank 101 of the external facility 100 from the pipe 12 (unloading
pipe 14) through the connection pipe 50 and the facility side pipe 102.
(Effects)
[0034] According to the method S10 for transferring liquefied carbon dioxide of the above-described
embodiment, gas on the inside of the connection pipe 50 and the pipe 12 is replaced
with the replacement gas Ga and then further replaced with the carbon dioxide gas
Gc. The moisture content of the replacement gas Ga is adjusted to be equal to or less
than a predetermined upper limit value. Accordingly, when the replacement gas Ga is
replaced with the carbon dioxide gas Gc, the reaction between the carbon dioxide gas
Gc and the moisture is suppressed. After replacing the inside of the connection pipe
50 and the pipe 12 with the carbon dioxide gas Gc, the liquefied carbon dioxide L
transferred between the external facility 100 and the tank 11 flows to the inside
of the connection pipe 50 and the pipe 12, and thus, even at this time, the occurrence
of the reaction between the carbon dioxide gas Gc and the moisture is suppressed.
Therefore, it is possible to suppress the reaction between the carbon dioxide and
the moisture when the liquefied carbon dioxide L is transferred, and to suppress the
occurrence of corrosion inside the tank 11 or the pipe 12.
[0035] Further, the replacement gas Ga is dry air having the moisture content adjusted to
be equal to or less than a predetermined upper limit value. The dry air used as the
replacement gas Ga can be formed by drying the air (atmosphere) with the air dryer
21. Therefore, it is possible to easily prepare the dry air on the ship 1.
[0036] Further, the carbon dioxide gas Gc is a boil-off gas formed by vaporization of the
liquefied carbon dioxide L stored in the tank 11. Accordingly, the carbon dioxide
gas Gc can be easily obtained on the ship 1.
[0037] In the ship 1 of the above-described embodiment, in a case where the connection pipe
50 for connection to the external facility 100 is connected to the pipe 12, the replacement
gas supply unit 20 feeds the replacement gas Ga having the moisture content adjusted
to be equal to or less than a predetermined upper limit value into the connection
pipe 50 and the pipe 12. Accordingly, the inside of the connection pipe 50 and the
pipe 12 can be replaced with the replacement gas Ga. Further, the carbon dioxide supply
unit 30 feeds the carbon dioxide gas Gc to the inside of the connection pipe 50 and
the pipe 12, and thus the replacement gas Ga can be replaced with the carbon dioxide
gas Gc on the inside of the connection pipe 50 and the pipe 12. After that, the liquefied
carbon dioxide L is transferred between the external facility 100 and the tank 11
through the connection pipe 50 and the pipe 12, and accordingly, it is possible to
suppress the reaction between the carbon dioxide and the moisture when the liquefied
carbon dioxide L is transferred, and to suppress the occurrence of corrosion inside
the tank 11 or the pipe 12.
[0038] In addition, the ship 1 includes the air dryer 21. Accordingly, by drying the atmosphere
(air) taken in from the outside by the air dryer 21, it is possible to provide the
dry air having the moisture content adjusted to be equal to or less than a predetermined
upper limit value as the replacement gas Ga. Accordingly, on the ship 1, it becomes
possible to easily obtain the replacement gas Ga having the moisture content adjusted
to be equal to or less than a predetermined upper limit value.
[0039] In addition, the ship 1 feeds the boil-off gas formed by the vaporization of the
liquefied carbon dioxide L stored in the tank 11 into the pipe 12 and the connection
pipe 50 as the carbon dioxide gas Gc. Accordingly, the carbon dioxide gas Gc can be
easily obtained on the ship 1.
(Other Embodiments)
[0040] 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 the embodiments,
and includes design changes and the like within a scope not departing from the gist
of the present disclosure.
[0041] In the above embodiment, as the connection portion 12j of the pipe 12, the connection
portion 13j of the loading pipe 13 and the connection portion 14j of the unloading
pipe 14 are individually provided, but the present disclosure is not limited thereto.
For example, the loading pipe 13 and the unloading pipe 14 may be connected to one
pipe 12 on the other end 13b and 14b sides, and the connection portion 12j may be
shared by the loading pipe 13 and the unloading pipe 14.
[0042] Further, in the above-described embodiment, the liquefied carbon dioxide L is transferred
between the ship 1 and the external facility 100 installed on land, but the present
disclosure is not limited thereto. The liquefied carbon dioxide L may be transferred
between the ship 1 and an offshore floating structure facility that is disposed offshore
and does not include a propulsion mechanism. In this case, the offshore floating structure
facility corresponds to the external facility 100 as viewed from the ship 1.
[0043] In the above embodiment, as the carbon dioxide gas Gc, a boil-off gas formed by vaporization
of the liquefied carbon dioxide L in the tank 11 is used. However, other than the
boil-off gas, the carbon dioxide gas Gc may be, for example, a carbon dioxide gas
accommodated in another container on the same ship or on the outside of the ship.
[0044] Further, in the ship 1 of the above embodiment, the configuration is provided with
two tanks 11, but the number and arrangement of the tanks 11 are not limited thereto.
Three or more tanks 11 may be provided. Further, in the above embodiment, a case where
the plurality of tanks 11 are disposed side by side in the stem-stern direction Da
has been shown. However, the tanks 11 may be disposed side by side in the ship width
direction (in other words, the left-right side direction). In addition, in the above
embodiment, the ship 1 is exemplified as the floating structure, but the present disclosure
is not limited thereto. The floating structure may be an offshore floating structure
facility that does not include a propulsion mechanism. In a case where the floating
structure is an offshore floating structure facility, the external facility 100 viewed
from the offshore floating structure facility may be a ship.
<Additional Note>
[0045] The method S10 for transferring the liquefied carbon dioxide L and the floating structure
1 described in each of the embodiments are ascertained as follows, for example.
- (1) According to a first aspect, there is provided a method S10 for transferring the
liquefied carbon dioxide L including: the step S11 of connecting the connection pipe
50 for connection to the external facility 100 disposed outside the floating structure
1 to the pipe 12 communicating with the inside of the tank 11 provided in the floating
structure 1; the step S12 of feeding the replacement gas Ga having the moisture content
adjusted to be equal to or less than a predetermined upper limit value into the connection
pipe 50 and the pipe 12, and replacing the inside of the connection pipe 50 and the
pipe 12 with the replacement gas Ga; the step S13 of replacing the replacement gas
Ga inside the connection pipe 50 and the pipe 12 with the carbon dioxide gas Gc; and
the step S14 of transferring the liquefied carbon dioxide L between the external facility
100 and the tank 11 through the connection pipe 50 and the pipe 12.
[0046] Examples of the floating structure 1 include a ship and an offshore floating structure
facility. Examples of the floating main structure 2 include the floating main structure
2 of a hull or an offshore floating structure facility.
[0047] Examples of the replacement gas Ga include dry air and an inert gas.
[0048] According to this method S10 for transferring liquefied carbon dioxide L, gas on
the inside of the connection pipe 50 and the pipe 12 is replaced with the replacement
gas Ga and then further replaced with the carbon dioxide gas Gc. Since the moisture
content of the replacement gas Ga is adjusted to be equal to or less than a predetermined
upper limit value, the reaction between the carbon dioxide and the moisture is suppressed
when the replacement gas Ga is replaced with the carbon dioxide gas Gc. After replacing
the inside of the connection pipe 50 and the pipe 12 with the carbon dioxide gas Gc,
the liquefied carbon dioxide L transferred between the external facility 100 and the
tank 11 flows into the connection pipe 50 and the pipe 12, and thus, even at this
time, the occurrence of the reaction between the carbon dioxide and the moisture is
suppressed. Therefore, it is possible to suppress the reaction between the carbon
dioxide and the moisture when the liquefied carbon dioxide L is transferred, and to
suppress the occurrence of corrosion inside the tank 11 or the pipe 12.
[0049] (2) In the method S10 for transferring the liquefied carbon dioxide L according to
a second aspect, which is the method S10 for transferring the liquefied carbon dioxide
L of (1), the replacement gas Ga is dry air having a moisture content adjusted to
be equal to or less than a predetermined upper limit value.
[0050] Accordingly, the dry air used as the replacement gas Ga can be formed by drying the
air (atmosphere) with the air dryer. Therefore, it is possible to easily prepare the
dry air on the floating structure 1.
[0051] (3) In the method S10 for transferring the liquefied carbon dioxide L according to
a third aspect, which is the method S10 for transferring the liquefied carbon dioxide
L of (1) or (2), the carbon dioxide gas Gc is a boil-off gas formed by vaporization
of the liquefied carbon dioxide L stored in the tank 11.
[0052] Accordingly, the carbon dioxide gas Gc can be easily obtained on the floating structure
1.
[0053] (4) According to a fourth aspect, there is provided the floating structure 1 including:
the floating main structure 2; the tank 11 disposed in the floating main structure
2 and capable of storing the liquefied carbon dioxide L; the pipe 12 which communicates
with the inside of the tank 11 and to which the connection pipe 50 for supplying the
liquefied carbon dioxide L between the external facility 100 and the tank 11 is connectable;
the replacement gas supply unit 20 that feeds the replacement gas Ga having a moisture
content adjusted to be equal to or less than a predetermined upper limit value into
the pipe 12 and the connection pipe 50 in a case where the connection pipe 50 is connected
to the pipe 12; and the carbon dioxide supply unit 30 that feeds the carbon dioxide
gas Gc into the pipe 12 and the connection pipe 50.
[0054] In the floating structure 1, the replacement gas supply unit 20 feeds the replacement
gas Ga having the moisture content adjusted to be equal to or less than a predetermined
upper limit value into the connection pipe 50 and the pipe 12, and accordingly, the
gas on the inside of the connection pipe 50 and the pipe 12 can be replaced with the
replacement gas Ga. Further, the carbon dioxide supply unit 30 feeds the carbon dioxide
gas Gc to the inside of the connection pipe 50 and the pipe 12, and thus the replacement
gas Ga can be replaced with the carbon dioxide gas Gc on the inside of the connection
pipe 50 and the pipe 12. After that, the liquefied carbon dioxide L is transferred
between the external facility 100 and the tank 11 through the connection pipe 50 and
the pipe 12, and accordingly, it is possible to suppress the reaction between the
carbon dioxide and the moisture when the liquefied carbon dioxide L is transferred,
and to suppress the occurrence of corrosion inside the tank 11 or the pipe 12.
[0055] (5) In the floating structure 1 according to a fifth aspect, which is the floating
structure 1 of (4), the replacement gas supply unit 20 includes the air dryer 21 that
reduces an amount of moisture contained in the atmosphere taken in from the outside.
[0056] Accordingly, the air dryer 21 reduces the moisture content in the atmosphere taken
in from the outside, and accordingly, the dry air can be provided as the replacement
gas Ga having the moisture content adjusted to be equal to or less than a predetermined
upper limit value.
[0057] (6) In the floating structure 1 according to a sixth aspect, which is the floating
structure 1 of (4) or (5), the carbon dioxide supply unit 30 feeds the boil-off gas
formed by vaporization of the liquefied carbon dioxide L stored in the tank 11 into
the pipe 12 and the connection pipe 50 as the carbon dioxide gas Gc.
[0058] Accordingly, by using the boil-off gas as the carbon dioxide gas Gc, the carbon dioxide
gas Gc can be easily obtained on the floating structure 1.
Industrial Applicability
[0059] According to the method for transferring liquefied carbon dioxide and the floating
structure according to the present disclosure, it is possible to suppress the reaction
between the carbon dioxide and the moisture when the liquefied carbon dioxide is transferred,
and to suppress the occurrence of corrosion inside the tank or the pipe.
Reference Signs List
[0060]
1: Ship (floating structure)
2: Hull (floating main structure)
2a: Stem
2b: Stern
3A, 3B: Side
4: Bottom
5: Upper deck
7: Superstructure
8: Cargo tank storage compartment
10: Tank facility
11: Tank
12: Pipe
12j: Connection portion
13: Loading pipe
13a: One end
13b: Other end
13j: Connection portion
14: Unloading pipe
14a: One end
14b: Other end
14j: Connection portion
15: Opening-closing valve
20: Replacement gas supply unit
21: Air dryer
22: Replacement gas supply pipe
23: Opening-closing valve
30: Carbon dioxide supply unit
50: Connection pipe
100: External facility
101: Facility side tank
102: Facility side pipe
105: Opening-closing valve
106: Opening valve
Ga: Replacement gas
Gc: Carbon dioxide gas
L: Liquefied carbon dioxide