Ship and method for use in ship

Abstract

A ship according to an embodiment comprises: a ship-side tank; a combustion unit; a first line for delivering liquefied ammonia from a supply-side tank to the ship-side tank; a second line for delivering ammonia gas from the ship-side tank to the supply-side tank; a third line connecting the first line and the second line; and a fourth line connecting the combustion unit and at least one of the first line and the second line.

Description

Ships and methods used on ships

[0001] FIELD OF THE INVENTION Embodiments of the present invention relate to ships and methods for use on ships.

[0002] As one of the efforts to reduce carbon dioxide emissions, ammonia-fueled ships that use ammonia as fuel are being considered.

[0003] Ammonia, whether in liquid or gas form, is highly likely to have adverse effects on the human body. Therefore, the structure and operation of the structure to safely replenish liquefied ammonia from the supply tank to the ship's tank are being considered.

[0004] Japan Special Table No. 2021-517878

[0005] Patent Document 1 discloses a bunkering system that transfers liquefied gas from a storage tank of a bunkering vessel to a fuel tank provided on a gas-propelled vessel. However, Patent Document 1 does not disclose the replenishment of liquefied ammonia.

[0006] An object of an embodiment of the present invention is to provide a technology that enables liquefied ammonia to be safely replenished from a supply tank to a ship's tank.

[0007] A first aspect of the ship according to the present embodiment is a ship comprising a ship-side tank, a combustion unit, a first line for sending liquefied ammonia from a supply-side tank to the ship-side tank, a second line for sending ammonia gas from the ship-side tank to the supply-side tank, a third line connecting the first line and the second line, and a fourth line connecting at least one of the first line and the second line to the combustion unit.

[0008] A method of a second aspect of the embodiment is a method used on the ship described in the first aspect, comprising: before replenishment of liquefied ammonia from the supply side tank to the ship side tank, opening a valve provided in the third line so as to change the state between the first line and the second line from a non-communicative state to a communicative state; supplying nitrogen gas to a target portion in a communicative state including the first line, the second line, and the third line; and after supplying nitrogen gas to the target portion, opening a valve provided in the fourth line so as to change the state between the target portion and the combustion section from a non-communicative state to a communicative state.

[0009] In a third aspect of the method according to the second aspect, the target portion includes a portion of the first line that is separated by the closure of a valve provided in the first line and that is not in communication with the ship's tank, a portion of the second line that is separated by the closure of a valve provided in the second line and that is not in communication with the ship's tank, and the third line.

[0010] A fourth aspect of the method of the embodiment is the method of the second aspect, wherein the supplying includes supplying nitrogen gas to the target portion until the pressure in the target portion becomes equal to or greater than a first threshold, and opening the valve provided in the fourth line includes opening the valve provided in the fourth line after the pressure in the target portion becomes equal to or greater than the first threshold, and further includes closing the valve provided in the fourth line after the pressure in the target portion becomes equal to or less than a second threshold that is lower than the first threshold.

[0011] A fifth aspect of the method of the fourth aspect of the present invention further comprises, in the method of the fourth aspect, repeating the supplying, opening the valve provided in the fourth line, and closing the valve provided in the fourth line if the gas concentration in the target portion does not satisfy the standard after closing the valve provided in the fourth line until the gas concentration in the target portion satisfies the standard.

[0012] A method of a sixth aspect of the embodiment is a method used on the ship described in the first aspect, comprising opening a valve provided on the fourth line so as to change the state between the second line and the combustion section from a non-communicating state to a communicating state before replenishment of liquefied ammonia from the supply side tank to the ship side tank.

[0013] A method of a seventh aspect of the embodiment is a method used on the ship described in the first aspect, comprising: before replenishment of liquefied ammonia from the supply side tank to the ship side tank, opening a valve provided on the third line so as to change the state between the first line and the second line from a non-communication state to a communication state; and opening a valve provided on the fourth line so as to change the state between the first line and the combustion section from a non-communication state to a communication state.

[0014] A method according to an eighth aspect of the embodiment is a method used on the ship according to the first aspect, comprising: before replenishment of liquefied ammonia from the supply-side tank to the ship's tank, closing a valve provided in the third line so as to change a state between the first line and the second line from a connected state to a disconnected state; opening a valve provided in the second line so as to change a state between a gas line connected to the supply-side tank and the ship's tank from a disconnected state to a connected state; and opening a valve provided in the first line so as to change a state between a liquid line connected to the supply-side tank and the ship's tank from a disconnected state to a connected state.

[0015] In a ninth aspect of the embodiment, in the method of the eighth aspect, during replenishment of liquefied ammonia from the supply side tank to the ship side tank, the liquefied ammonia in the liquid line and the first line is sent to the ship side tank by ammonia gas compressed by a compressor.

[0016] A method of a tenth aspect of the embodiment is a method used on the ship described in the first aspect, comprising, after replenishment of liquefied ammonia from the supply side tank to the ship side tank, opening a valve provided in the third line to change the state between the first line and the second line from a connected state to a disconnected state, and opening a valve provided in the fourth line to change the state between the first line and the combustion section from a disconnected state to a connected state.

[0017] The method of an eleventh aspect of the embodiment is a method used on the ship described in the first aspect, comprising: after replenishment of liquefied ammonia from the supply side tank to the ship side tank, supplying nitrogen gas to a target portion including the first line, the second line, and the third line; and after supplying nitrogen gas to the target portion, opening a valve provided on the fourth line so as to change the state between the target portion and the combustion section from a non-communicative state to a communicative state.

[0018] A twelfth aspect of the method according to the eleventh aspect of the present invention is the method of the eleventh aspect, further comprising: after opening the valve provided in the fourth line, closing the valve provided in the fourth line; and, if the gas concentration in the target portion after closing the valve provided in the fourth line does not satisfy a standard, repeating the supplying, opening the valve provided in the fourth line, and closing the valve provided in the fourth line until the gas concentration in the target portion satisfies the standard.

[0019] A method of a thirteenth aspect of the embodiment is a method used on the ship described in the first aspect, comprising: after liquefied ammonia is replenished from the supply side tank to the ship side tank, opening a valve provided in the fourth line so as to change the state between the first line and the combustion section from a non-communicative state to a communicative state; and closing the valve provided in the fourth line after the pressure in the first line becomes equal to or lower than a threshold value.

[0020] A method of a fourteenth aspect of the embodiment is a method used on the ship described in the first aspect, comprising: after liquefied ammonia is replenished from the supply side tank to the ship side tank, opening a valve provided in the fourth line so as to change the state between the second line and the combustion section from a non-communicative state to a communicative state; and closing the valve provided in the fourth line after the pressure in the second line becomes equal to or lower than a threshold value.

[0021] The method of a fifteenth aspect of the embodiment is the method of any one of the sixth, seventh, tenth, and eleventh aspects, further comprising closing a valve provided in the fourth line based on a change in combustion conditions in the combustion section.

[0022] According to the embodiment, it is possible to safely replenish liquefied ammonia from the supply tank to the ship's tank.

[0023] FIG. 1 is a diagram illustrating the configuration of a ship and a tank truck according to an embodiment. FIG. 2 is a diagram illustrating a method for checking airtightness using nitrogen gas according to an embodiment. FIG. 3 is a diagram illustrating a method for checking airtightness using nitrogen gas according to an embodiment. FIG. 4 is a diagram illustrating a method for checking airtightness using nitrogen gas according to an embodiment. FIG. 5 is a diagram illustrating a method for testing an ESD according to an embodiment. FIG. 6 is a diagram illustrating a method for treating residual liquid in a supply-side gas line according to an embodiment. FIG. 7 is a diagram illustrating a method for treating residual liquid in a supply-side gas line according to an embodiment. FIG. 8 is a diagram illustrating a method for treating residual liquid in a ship-side gas line according to an embodiment. FIG. 9 is a diagram illustrating a method for treating residual liquid in a ship-side gas line according to an embodiment. FIG. 10 is a diagram illustrating a method for treating residual liquid in a ship-side liquid line according to an embodiment. FIG. 11 is a diagram illustrating a method for treating residual liquid in a ship-side liquid line according to an embodiment. FIG. 12 is a diagram illustrating a method for preparing for replenishment according to an embodiment. FIG. 13 is a diagram illustrating a method for replenishing a second ship-side tank according to an embodiment. FIG. 14 is a diagram illustrating a method for switching ship-side tanks according to an embodiment. FIG. 15 is a diagram for explaining a first example of a top-up operation method according to the embodiment. FIG. 16 is a diagram for explaining a second example of a top-up operation method according to the embodiment. FIG. 17 is a diagram for explaining a third example of a top-up operation method according to the embodiment. FIG. 18 is a diagram for explaining a fourth example of a top-up operation method according to the embodiment. FIG. 19 is a diagram for explaining a top-up operation completion method according to the embodiment. FIG. 20 is a diagram for explaining a method for burning residual gas in a line according to the embodiment. FIG. 21 is a diagram for explaining a method for burning residual gas in a line according to the embodiment. ２ 22 is a diagram for explaining a purging method. ２ FIG. 10 is a diagram for explaining a purging method.

[0024] The embodiments will be described with reference to the drawings. Note that the scale of each part in the drawings used in the following description of the embodiments may be changed as appropriate. Also, for the sake of explanation, the drawings used in the following description of the embodiments may omit components.

[0025] (Embodiment) <Configuration Example> FIG. 1 is a diagram illustrating the configuration of a ship 1 and a tanker truck 2. As shown in FIG.

[0026] The ship 1 is an ammonia-fueled ship that uses ammonia as fuel for propulsion. The ship 1 is not limited to ships that use only ammonia as fuel. The ship 1 may also be a ship that uses fuel other than ammonia, such as heavy oil, in addition to ammonia. The term "ammonia" may refer to either ammonia gas or liquefied ammonia, or may refer to both.

[0027] The ship 1 includes a first ship tank 11-1, a second ship tank 11-2, a GCU (Gas Combustion Unit) 12, a nitrogen gas cylinder 13, a ship liquid line 14, a ship gas line 15, a connection line 16, a combustion line 17, a nitrogen line 18, and a concentration detection line 19. The line is a structure that forms a fluid path that allows a fluid such as a liquid or gas to flow through the space within the line. The line is composed of one or more pipes. The line may include a rigid metal pipe. The line may include a flexible pipe such as a hose.

[0028] The first ship's side tank 11-1 is a tank for storing liquefied ammonia. The first ship's side tank 11-1 is an example of a ship's side tank provided on the ship 1. The second ship's side tank 11-2 is a tank for storing liquefied ammonia. The second ship's side tank 11-2 is an example of a ship's side tank provided on the ship 1. Hereinafter, the ship's side tank refers to the first ship's side tank 11-1 and the second ship's side tank 11-2.

[0029] The GCU 12 is a device that combusts ammonia gas. The GCU 12 is an example of a combustion unit that combusts ammonia gas.

[0030] The nitrogen gas cylinder 13 is a cylinder that supplies nitrogen gas and is an example of a nitrogen gas supply unit that supplies nitrogen gas.

[0031] The ship side liquid line 14 is connected to the supply side liquid line 23 and the ship side tank. The ship side liquid line 14 connects the supply side liquid line 23 and the ship side tank. The ship side liquid line 14 is a line for sending liquefied ammonia from the supply side tank 21 to the ship side tank. The end of the ship side liquid line 14 that connects to the supply side liquid line 23 is referred to as the first end 141. The first end 141 of the ship side liquid line 14 is detachable from the supply side liquid line 23. The end of the ship side liquid line 14 that connects to the first ship side tank 11-1 is referred to as the second end 142-1. The end of the ship side liquid line 14 that connects to the second ship side tank 11-2 is referred to as the second end 142-2. Hereinafter, the second end of the ship side liquid line 14 refers to the second end 142-1 and the second end 142-2.

[0032] The ship 1 is equipped with valves V16, V17, 1V15, and 2V15 provided in the ship's side liquid line 14. Of the multiple valves provided in the ship's side liquid line 14, valve V17 is the valve closest to the first end 141 of the ship's side liquid line 14. Of the multiple valves provided in the ship's side liquid line 14, valve 1V15 is the valve closest to the second end 142-1 of the ship's side liquid line 14. Of the multiple valves provided in the ship's side liquid line 14, valve 2V15 is the valve closest to the second end 142-2 of the ship's side liquid line 14. Valve V16 is a valve between valve V17 and valve 1V15 or valve 2V15.

[0033] The ship side gas line 15 is connected to the supply side gas line 24 and the ship side tank. The ship side gas line 15 connects the supply side gas line 24 and the ship side tank. The ship side gas line 15 is a line for sending ammonia gas from the ship side tank to the supply side tank 21. The end of the ship side gas line 15 that connects to the supply side gas line 24 is referred to as a first end 151. The first end 151 of the ship side gas line 15 is detachable from the supply side gas line 24. The end of the ship side gas line 15 that connects to the first ship side tank 11-1 is referred to as a second end 152-1. The end of the ship side gas line 15 that connects to the second ship side tank 11-2 is referred to as a second end 152-2. Hereinafter, the second end of the ship side gas line 15 refers to the second end 152-1 and the second end 152-2.

[0034] The ship 1 is equipped with valves V19, V20, valve 1V18, and valve 2V18 provided in the ship's side gas line 15. Of the multiple valves provided in the ship's side gas line 15, the valve V20 is the valve closest to the first end 151 of the ship's side gas line 15. Of the multiple valves provided in the ship's side gas line 15, the valve 1V18 is the valve closest to the second end 152-1 of the ship's side gas line 15. Of the multiple valves provided in the ship's side gas line 15, the valve 2V18 is the valve closest to the second end 152-2 of the ship's side gas line 15. The valve V19 is a valve between the valve V20 and the valve 1V18 or the valve 2V18.

[0035] The connecting line 16 connects the ship side liquid line 14 and the ship side gas line 15. The connecting line 16 is connected to the ship side liquid line 14 between a first end 141 and the valve V17. The connecting line 16 is connected to the ship side gas line 15 between a first end 151 and the valve V20. The ship 1 is provided with a valve V21 provided in the connecting line 16.

[0036] The combustion line 17 connects the ship side liquid line 14 to the GCU 12, and also connects the ship side gas line 15 to the GCU 12. The combustion line 17 includes a first combustion line connected in the ship side liquid line 14 between the valve V16 and the valve 1V15 or the valve 2V15. The combustion line 17 includes a second combustion line connected in the ship side liquid line 14 between the valve V16 and the valve V17. The combustion line 17 includes a third combustion line connected in the ship side gas line 15 between the valve V19 and the valve 1V18 or the valve 2V18. Note that the combustion line 17 may connect at least one of the ship side liquid line 14 and the ship side gas line 15 to the GCU 12.

[0037] The ship 1 is equipped with valves V47, V48, and V51 provided in the combustion line 17. Valve V47 is a valve provided in a first combustion line included in the combustion line 17. Valve V48 is a valve provided in a second combustion line included in the combustion line 17. Valve V51 is a valve provided in a third combustion line included in the combustion line 17.

[0038] The nitrogen line 18 connects the ship side liquid line 14 and the nitrogen gas cylinder 13. The nitrogen line 18 is connected in the ship side liquid line 14 between the first end 141 and the valve V17. The nitrogen line 18 may connect at least one of the ship side liquid line 14 and the ship side gas line 15 to the nitrogen gas cylinder 13. The ship 1 is equipped with valves VN17 and VN18 provided in the nitrogen line 18.

[0039] The concentration detection line 19 is connected to the ship side liquid line 14. The concentration detection line 19 is connected to the ship side liquid line 14 between the first end 141 and the valve V17. The ship 1 is provided with a valve V32 provided on the concentration detection line 19. The tank truck 2 is a vehicle that transports liquefied ammonia to be supplied to the ship 1. The tank truck 2 is provided with a supply side tank 21, a compressor 22, a supply side liquid line 23, and a supply side gas line 24.

[0040] The supply tank 21 is a tank for storing liquefied ammonia.

[0041] The compressor 22 compresses the ammonia gas. The compressor 22 is provided on the supply gas line 24.

[0042] The supply side liquid line 23 is connected to the ship side liquid line 14 and the supply side tank 21. The supply side liquid line 23 connects the ship side liquid line 14 and the supply side tank 21. The supply side liquid line 23 is a line for sending liquefied ammonia from the supply side tank 21 to the ship side tank. The supply side liquid line 23 is detachable from the ship side liquid line 14.

[0043] The tank truck 2 is equipped with valves V1, V3, and EV1 provided in the supply-side liquid line 23. Of the multiple valves provided in the supply-side liquid line 23, valve V1 is the valve closest to the end of the supply-side liquid line 23 that connects to the ship side liquid line 14. Of the multiple valves provided in the supply-side liquid line 23, valve EV1 is the valve closest to the supply-side tank 21. Valve V3 is a valve between valves V1 and EV1.

[0044] The supply-side gas line 24 is connected to the ship-side gas line 15 and the supply-side tank 21. The supply-side gas line 24 connects the ship-side gas line 15 and the supply-side tank 21. The supply-side gas line 24 is a line for sending ammonia gas from the ship-side tank to the supply-side tank 21. The supply-side gas line 24 is detachable from the ship-side gas line 15.

[0045] The tank truck 2 includes valves V2, V6, V12, V13, and EV2 provided in the supply-side gas line 24. Of the multiple valves provided in the supply-side gas line 24, the valve V2 is the valve closest to the end of the supply-side gas line 24 that connects to the ship side gas line 15. Of the multiple valves provided in the supply-side gas line 24, the valve EV2 is the valve closest to the supply-side tank 21. The valves V6, V12, and V13 are valves between the valve V2 and the valve EV2.

[0046] The tank truck 2 includes a valve V5 provided on a line connecting the supply-side liquid line 23 and the supply-side gas line 24. The line on which the valve V5 is provided is connected between the valves V1 and V3 in the supply-side liquid line 23. The line on which the valve V5 is provided is connected between the valves V2 and V6 in the supply-side gas line 24.

[0047] The valves provided in each line can be opened and closed. When the valves are open, they open the line. In this case, the valves do not divide the space within the line and therefore do not hinder the movement of fluid within the line. When the valves are closed, they close the line. In this case, the valves divide the space within the line and therefore hinder the movement of fluid within the line. The valves may be opened and closed by direct human operation. The valves may also be opened and closed automatically in response to an open or close command input by a human operating a switch or the like.

[0048] The arrangement of each line is not limited to the example shown in Fig. 1. The arrangement of each line can be changed as appropriate. The number and positions of valves provided in each line are not limited to the example shown in Fig. 1. The number and positions of valves provided in each line can be changed as appropriate.

[0049] Each line is provided with a pressure gauge to measure the pressure inside the line. The first ship's tank 11-1, the second ship's tank 11-2, and the supply tank 21 are provided with a pressure gauge to measure the pressure inside the tank.

[0050] Liquefied ammonia is replenished from the supply-side tank 21 to the ship's side tank as follows: When the liquefied ammonia stored in the ship's side tank evaporates, ammonia gas enters the ship's side tank into the ship's side gas line 15. The ammonia gas flows from the ship's side tank to the supply-side tank 21 via the ship's side gas line 15 and the supply-side gas line 24. The ammonia gas is compressed by a compressor 22 provided in the supply-side gas line 24. The compressed ammonia gas pressurizes the supply-side tank 21. The liquefied ammonia stored in the supply-side tank 21 is pressurized by the ammonia gas and pressure-transferred from the supply-side tank 21 to the ship's side tank via the supply-side liquid line 23 and the ship's side liquid line 14.

[0051] The ship 1 described above is configured to send ammonia gas from the ship's tank to the supply tank 21 in order to replenish the ship's tank with liquefied ammonia from the supply tank 21. Therefore, while liquefied ammonia is being replenished from the supply tank 21 to the ship's tank, it is not necessary to combust the ammonia gas vaporized from the liquefied ammonia in the ship's tank in the GCU 12. The ship 1 described above is also configured to connect the ship's liquid line 14 and the ship's gas line 15 with a connecting line 16. Therefore, the ship 1 can efficiently combust the ammonia remaining in the ship's liquid line 14 and the ship's gas line 15 in the GCU 12 by appropriately connecting the ship's liquid line 14 and the ship's gas line 15 before or after replenishment with liquefied ammonia. In this way, the ship 1 enables safe replenishment of liquefied ammonia from the supply tank 21 to the ship's tank.

[0052] <Bunkering Method> The bunkering method is a method for supplying liquefied ammonia from the supply-side tank 21 to the ship-side tank after the ship-side liquid line 14 is connected to the supply-side liquid line 23 and the ship-side gas line 15 is connected to the supply-side gas line 24. Bunkering methods include a method used on the ship 1 and a method used on the tank truck 2.

[0053] The bunkering method may include some or all of the methods (1) to (12) described below. Methods (1) to (6) are methods used before replenishment of liquefied ammonia from the supply-side tank 21 to the ship's tank. Methods (7) to (10) are methods used during replenishment of liquefied ammonia from the supply-side tank 21 to the ship's tank. Methods (11) and (12) are methods used after replenishment of liquefied ammonia from the supply-side tank 21 to the ship's tank. Note that the steps described below are merely examples, and the order of the steps can be changed, steps can be omitted, and steps can be added as appropriate.

[0054] In Figure 2 and subsequent figures, the valves depicted in white indicate closed valves. The valves depicted in black indicate open valves. The thick black line inside the outer rim indicates liquefied ammonia in the line. The thick vertical striped line inside the outer rim indicates ammonia gas in the line. The thick diagonal striped line inside the outer rim indicates nitrogen gas in the line.

[0055] In the following description, a communicating portion refers to a portion that is spatially continuous. A communicating portion is a portion through which a fluid can move. A non-communicating portion refers to a portion that is not spatially continuous. A non-communicating portion is a portion through which a fluid cannot move. A communicating state refers to a state that is spatially continuous. A communicating state refers to a state through which a fluid can move. A non-communicating state refers to a state that is not spatially continuous. A non-communicating state refers to a state through which a fluid cannot move.

[0056] (1) Method for checking airtightness with nitrogen gas The bunkering method includes a method for checking airtightness with nitrogen gas. The method for checking airtightness with nitrogen gas is a method for checking the airtightness of a line. The method for checking airtightness with nitrogen gas includes steps 1A to 1J, which will be described later.

[0057] 2 to 4 are diagrams for explaining a method for checking airtightness using nitrogen gas. Fig. 2 is a diagram related to steps 1A to 1D. Fig. 3 is a diagram related to steps 1E to 1G. Fig. 4 is a diagram related to steps 1H to 1J.

[0058] The open / closed state of each valve before starting the method for checking airtightness with nitrogen gas is referred to as the first open / closed state. The first open / closed state is as follows: No valves are open on Ship 1. The closed valves on Ship 1 are valve V16, valve V17, valve V19, valve V20, valve V21, valve V32, valve V47, valve V48, valve V51, valve 1V15, valve 2V15, valve 1V18, valve 2V18, valve VN17, and valve VN18. No valves are open on Tanker Truck 2. The closed valves on Tanker Truck 2 are valve V1, valve V2, valve V3, valve V5, valve V6, valve V12, valve V13, valve EV1, and valve EV2.

[0059] (Step 1A) The tank truck 2 is notified that the vessel side liquid line 14 and the vessel side gas line 15 are to be filled with nitrogen gas.

[0060] (Step 1B) Valve V17 is opened. The communicating portion of the ship side liquid line 14 from the first end 141 to the closed valve V16 is referred to as portion A1. Portion A1 of the ship side liquid line 14 is a portion that is separated by the closure of valve V16 and is not in communication with the ship side tank. Portion A1 of the ship side liquid line 14 is an example of a ship side liquid line 14. The communicating portion of the supply side liquid line 23 from the end that connects to the ship side liquid line 14 to the closed valve V1 is referred to as portion B1. Portion B1 of the supply side liquid line 23 is a portion that is separated by the closure of valve V1 and is not in communication with the supply side tank 21. Portion B1 of the supply side liquid line 23 is an example of a supply side liquid line 23. Portion A1 of the ship side liquid line 14 is a portion that is in communication with portion B1 of the supply side liquid line 23. Opening valve V17 forms portion A1 of the ship side liquid line 14.

[0061] The valve V20 is opened. The communicating portion of the ship side gas line 15 from the first end 151 to the closed valve V19 is referred to as portion C1. The portion C1 of the ship side gas line 15 is a portion that is separated by the closure of the valve V19 and is not in communication with the ship side tank. The portion C1 of the ship side gas line 15 is an example of the ship side gas line 15. The communicating portion of the supply side gas line 24 from the end that connects to the ship side gas line 15 to the closed valve V2 is referred to as portion D1. The portion D1 of the supply side gas line 24 is a portion that does not pass through the compressor 22. The portion D1 of the supply side gas line 24 is a portion that is separated by the closure of the valve V2 and is not in communication with the supply side tank 21. The portion D1 of the supply side gas line 24 is an example of the supply side gas line 24. The portion C1 of the ship side gas line 15 is a portion that is in communication with the portion D1 of the supply side gas line 24. By opening the valve V20, the portion C1 of the ship side gas line 15 is formed.

[0062] Valve V21 is opened. Opening valve V21 changes the state between portion A1 of the ship side liquid line 14 and portion C1 of the ship side gas line 15 from a non-communication state to a communication state. This forms the target portion. The target portion includes portion A1 of the ship side liquid line 14, portion C1 of the ship side gas line 15, and the connecting line 16. The target portion is a connected portion composed of portion A1 of the ship side liquid line 14, portion C1 of the ship side gas line 15, and the connecting line 16. The target portion is a connected portion. The target portion is a portion that is not connected to the ship side tank.

[0063] (Step 1C) Valves VN17 and VN18 are opened. By opening valves VN17 and VN18, nitrogen gas is supplied to the target portion from nitrogen gas cylinder 13. In a specific example, nitrogen gas is supplied to the target portion until the pressure in the target portion reaches or exceeds a first threshold. For example, the first threshold is 1.5 MPa, but is not limited to this. The first threshold can be set as appropriate.

[0064] (Step 1D) Spray foaming liquid at the connection between the ship side liquid line 14 and the supply side liquid line 23, and check for gas leakage from the connection between the ship side liquid line 14 and the supply side liquid line 23. Spray foaming liquid at the connection between the ship side gas line 15 and the supply side gas line 24, and check for gas leakage from the connection between the ship side gas line 15 and the supply side gas line 24.

[0065] (Step 1E) The valves VN17 and VN18 are closed. In a specific example, the valves VN17 and VN18 are closed after the pressure in the target portion has reached or exceeded the first threshold due to the supply of nitrogen gas to the target portion. Closing the valves VN17 and VN18 stops the supply of nitrogen gas to the target portion.

[0066] (Step 1F) The operation of the GCU 12 is started.

[0067] (Step 1G) After supplying nitrogen gas to the target portion, valve V48 is opened. In a specific example, V48 is opened after the pressure in the target portion becomes equal to or greater than the first threshold due to the supply of nitrogen gas to the target portion. Opening valve V48 changes the state between the target portion and GCU 12 from a non-communication state to a communication state. Nitrogen gas in the target portion flows from the target portion to GCU 12. If ammonia gas remains in the target portion, the ammonia gas remaining in the target portion flows from the target portion to GCU 12. If liquefied ammonia remains in the target portion, the liquefied ammonia remaining in the target portion flows from the target portion to GCU 12. The liquefied ammonia may be vaporized in the process of flowing from the target portion to GCU 12. The GCU 12 can combust the nitrogen gas and ammonia gas that have flowed to the GCU 12. The GCU 12 can combust the ammonia gas after vaporizing the liquefied ammonia that has flowed to the GCU 12.

[0068] (Step 1H) After the valve V48 is opened and the gas flowing from the target portion to the GCU 12 is combusted in the GCU 12, the valve V48 is closed. In a specific example, after the valve V48 is opened, the valve V48 is closed after the pressure in the target portion falls below a second threshold value that is lower than the first threshold value. For example, the second threshold value is 0.1 MPa, but is not limited to this. The second threshold value can be set as appropriate. Closing the valve V48 changes the state between the target portion and the GCU 12 from a connected state to a disconnected state.

[0069] (Step 1I) Open the valve V32. Measure the gas concentration in the target portion. After measuring the gas concentration in the target portion, close the valve V32. For example, the gas concentration in the target portion is an oxygen concentration, but is not limited to this. The gas concentration in the target portion may also be an ammonia concentration.

[0070] (Step 1J) If the gas concentration in the target portion after closing valve V48 satisfies the first criterion, the method for checking airtightness with nitrogen gas is terminated. For example, the gas concentration in the target portion satisfies the first criterion when the oxygen concentration in the target portion is 4 vol% or less, but is not limited to this. The first criterion can be changed as appropriate. The gas concentration in the target portion can be used to determine whether the amount of ammonia remaining in the target portion is decreasing.

[0071] If the gas concentration in the target portion after closing valve V48 does not satisfy the first criterion, steps 1C to 1I are repeated until the gas concentration in the target portion satisfies the first criterion.

[0072] The open / closed state of each valve after the completion of the method for checking airtightness using nitrogen gas is referred to as the second open / closed state. The second open / closed state is as follows: The valves that are open on Ship 1 are Valve V17, Valve V20, and Valve V21. The valves that are closed on Ship 1 are Valve V16, Valve V19, Valve V32, Valve V47, Valve V48, Valve V51, Valve 1V15, Valve 2V15, Valve 1V18, Valve 2V18, Valve VN17, and Valve VN18. No valves are open on Tanker Truck 2. The valves that are closed on Tanker Truck 2 are Valve V1, Valve V2, Valve V3, Valve V5, Valve V6, Valve V12, Valve V13, Valve EV1, and Valve EV2.

[0073] According to the method of checking airtightness with nitrogen gas, before replenishment of liquefied ammonia, nitrogen gas can be used to safely check the airtightness of the ship's liquid line 14 and the ship's gas line 15. Furthermore, according to the method of checking airtightness with nitrogen gas, before replenishment of liquefied ammonia, nitrogen gas can be used to treat ammonia remaining in the ship's liquid line 14 and the ship's gas line 15. By performing such a process before replenishment of liquefied ammonia, replenishment of liquefied ammonia from the supply-side tank 21 to the ship's tank can be safely performed.

[0074] (2) Method for Testing ESD (Emergency Shut Down) The bunkering method includes a method for testing ESD. The method for testing ESD is a method for testing the operation of a valve that automatically opens and closes in response to an open command or a close command. For example, valves V17 and V18 are valves that automatically open and close. The method for testing ESD includes steps 2A to 2C.

[0075] 5 is a diagram for explaining a method for testing ESD. Before the start of the method for testing ESD, the open / closed state of each valve is the second open / closed state described above.

[0076] (Step 2A) The valve V21 is closed. By closing the valve V21, the state between the ship side liquid line 14 and the ship side gas line 15 is changed from a communication state to a non-communication state.

[0077] (Step 2B) Test the valve V17 in a room temperature environment. For example, input a close command to automatically close the valve V17. Confirm that the valve V17 automatically closes in accordance with the input close command. After confirming that the valve V17 automatically closes, input an open command to automatically open the valve V17, thereby opening the valve V17.

[0078] (Step 2C) Valve V20 is tested in a room temperature environment. For example, a close command is input to automatically close valve V20. It is confirmed that valve V20 automatically closes in accordance with the input close command. After confirming that valve V20 automatically closes, an open command is input to automatically open valve V20, thereby opening valve V20.

[0079] The open / closed state of each valve after the completion of the method for testing the ESD is referred to as the third open / closed state. The third open / closed state is as follows: The valves that are open on Ship 1 are Valve V17 and Valve V20. The valves that are closed on Ship 1 are Valve V16, Valve V19, Valve V21, Valve V32, Valve V47, Valve V48, Valve V51, Valve 1V15, Valve 2V15, Valve 1V18, Valve 2V18, Valve VN17, and Valve VN18. There are no valves that are open on Tanker Truck 2. The valves that are closed on Tanker Truck 2 are Valve V1, Valve V2, Valve V3, Valve V5, Valve V6, Valve V12, Valve V13, Valve EV1, and Valve EV2.

[0080] According to the method for testing the ESD, it is possible to check the operation of the automatically opening and closing valve before refueling with liquefied ammonia. By carrying out such a process before refueling with liquefied ammonia, it is possible to safely refuel liquefied ammonia from the supply-side tank 21 to the ship's tank.

[0081] (3) Method for Treating Residual Liquid in Supply-Side Gas Line 24 The bunkering method includes a method for treating residual liquid in the supply-side gas line 24. The method for treating residual liquid in the supply-side gas line 24 is a method for treating liquefied ammonia formed by re-liquefying ammonia gas remaining in the supply-side gas line 24. The method for treating residual liquid in the supply-side gas line 24 includes steps 3A to 3I, which will be described later.

[0082] 6 and 7 are diagrams for explaining a method for treating residual liquid in the supply-side gas line 24. Fig. 6 is a diagram related to steps 3A to 3F. Fig. 7 is a diagram related to steps 3G to 3I. Before starting the method for treating residual liquid in the supply-side gas line 24, the open / close states of the valves are the third open / close state, with valve V20 closed.

[0083] (Step 3A) Open the valves EV1 and EV2. In a specific example, the valves EV1 and EV2 are opened simultaneously.

[0084] (Step 3B) Valve V6 is opened. The portion of the supply side gas line 24 that communicates from the supply side tank 21 to the closed valve V2 is referred to as portion D2. Portion D2 of the supply side gas line 24 is a portion that does not pass through the compressor 22. Portion D2 of the supply side gas line 24 is a portion that is in communication with the supply side tank 21. Portion D2 of the supply side gas line 24 is a portion that is not in communication with the ship side gas line 15. Portion D2 of the supply side gas line 24 is an example of the supply side gas line 24.

[0085] The opening of valve EV2 in step 3A and the opening of valve V6 in step 3B form portion D2 of supply gas line 24.

[0086] (Step 3C) Valve V5 is opened.

[0087] (Step 3D) Valve V1 is opened.

[0088] (Step 3E) The valve V48 is opened. By opening the valve V48, the state between the portion D2 of the supply side gas line 24 and the GCU 12 is changed from a non-communication state to a communication state. The liquefied ammonia remaining in the portion D2 of the supply side gas line 24 flows from the portion D2 of the supply side gas line 24 to the GCU 12. The liquefied ammonia may be vaporized in the process of flowing from the portion D2 of the supply side gas line 24 to the GCU 12.

[0089] (Step 3F) The ammonia that has flowed from the portion D2 of the supply-side gas line 24 to the GCU 12 is combusted in the GCU 12. The GCU 12 can combust ammonia gas that has been vaporized from the liquefied ammonia in the process of flowing from the portion D2 of the supply-side gas line 24 to the GCU 12. The GCU 12 can combust the ammonia gas after vaporizing the liquefied ammonia that has flowed from the portion D2 of the supply-side gas line 24 to the GCU 12.

[0090] (Step 3G) After the valve V48 is opened and the ammonia flowing from the portion D2 of the supply gas line 24 to the GCU 12 is combusted in the GCU 12, the valve V48 is closed. Closing the valve V48 changes the state between the portion D2 of the supply gas line 24 and the GCU 12 from a connected state to a disconnected state. For example, the valve V48 can be closed based on the amount of ammonia combusted in the GCU 12. The amount of ammonia combusted in the GCU 12 may be measured using a flow meter. The ammonia amount threshold used as a guide for closing the valve V48 can be set appropriately. Note that the valve V48 may also be closed based on changes in the combustion status in the GCU 12. The combustion status in the GCU 12 represents how the gas is combusting in the GCU 12. For example, the combustion status in the GCU 12 is the temperature of combustion in the GCU 12, but is not limited thereto. As the amount of liquefied ammonia remaining in portion D2 of supply-side gas line 24 decreases due to the combustion of ammonia in GCU 12, the temperature of combustion in GCU 12 changes. Therefore, it can be determined that the amount of liquefied ammonia remaining in portion D2 of supply-side gas line 24 is decreasing due to the change in the temperature of combustion in GCU 12. Valve V48 may be closed based on the change in gas concentration in portion D2 of supply-side gas line 24.

[0091] (Step 3H) Valve V1 is closed.

[0092] (Step 3I) Valve V5 is closed.

[0093] The open / close state of each valve after completion of the method for treating residual liquid in the supply-side gas line 24 will be referred to as the fourth open / close state. The fourth open / close state is as follows: The valve that is open on ship 1 is valve V17. The valves that are closed on ship 1 are valve V16, valve V19, valve V20, valve V21, valve V32, valve V47, valve V48, valve V51, valve 1V15, valve 2V15, valve 1V18, valve 2V18, valve VN17, and valve VN18. The valves that are open on tanker truck 2 are valve V6, valve EV1, and valve EV2. The valves that are closed on tanker truck 2 are valve V1, valve V2, valve V3, valve V5, valve V12, and valve V13.

[0094] According to the method for treating the residual liquid in the supply-side gas line 24, it is possible to treat the re-liquefied liquefied ammonia remaining in the supply-side gas line 24 before replenishment of liquefied ammonia. If liquefied ammonia remains in the supply-side gas line 24, there is a risk that the liquefied ammonia remaining in the supply-side gas line 24 will flow into the operating compressor 22 during replenishment of liquefied ammonia. Therefore, before replenishment of liquefied ammonia, it is necessary to create a completely gaseous atmosphere inside the supply-side gas line 24. By performing such a process before replenishment of liquefied ammonia, liquefied ammonia can be safely replenished from the supply-side tank 21 to the ship's tank.

[0095] (4) Method for Treating Residual Liquid in Ship Side Gas Line 15 The bunkering method includes a method for treating residual liquid in the ship side gas line 15. The method for treating residual liquid in the ship side gas line 15 is a method for treating liquefied ammonia formed by re-liquefying ammonia gas remaining in the ship side gas line 15. The method for treating residual liquid in the ship side gas line 15 includes steps 4A to 4E, which will be described later.

[0096] 8 and 9 are diagrams for explaining a method for treating residual liquid in the ship side gas line 15. Fig. 8 is a diagram related to steps 4A to 4D. Fig. 9 is a diagram related to step 4E. The open / close state of each valve before starting the method for treating residual liquid in the ship side gas line 15 is the fourth open / close state described above.

[0097] (Step 4A) Valve 1V18 is opened.

[0098] (Step 4B) Valve 2V18 is opened.

[0099] The portion of the ship side gas line 15 that is connected from the ship side tank to the closed valve V19 is referred to as portion C2. The portion C2 of the ship side gas line 15 is a portion that is connected to the ship side tank. The portion C2 of the ship side gas line 15 is a portion that is not connected to the supply side gas line 24. The portion C2 of the ship side gas line 15 is an example of the ship side gas line 15.

[0100] By opening the valve 1V18 in step 4A and the valve 2V18 in step 4B, the portion C2 of the ship side gas line 15 is formed.

[0101] (Step 4C) The valve V51 is opened. For example, the valve V51 is opened slightly open. Opening the valve V51 changes the state between the portion C2 of the ship side gas line 15 and the GCU 12 from a non-communication state to a communication state. The liquefied ammonia remaining in the portion C2 of the ship side gas line 15 flows from the portion C2 of the ship side gas line 15 to the GCU 12. The liquefied ammonia may be vaporized in the process of flowing from the portion C2 of the ship side gas line 15 to the GCU 12.

[0102] (Step 4D) The ammonia that has flowed from the portion C2 of the ship side gas line 15 to the GCU 12 is combusted in the GCU 12. The GCU 12 can combust ammonia gas that has been vaporized from the liquefied ammonia in the process of the ammonia flowing from the portion C2 of the ship side gas line 15 to the GCU 12. The GCU 12 can combust the ammonia gas after vaporizing the liquefied ammonia that has flowed from the portion C2 of the ship side gas line 15 to the GCU 12.

[0103] (Step 4E) After the valve V51 is opened and the ammonia that has flowed from the portion C2 of the ship gas line 15 to the GCU 12 is combusted in the GCU 12, the valve V51 is closed. Closing the valve V51 changes the state between the portion C2 of the ship gas line 15 and the GCU 12 from a connected state to a disconnected state. For example, the valve V51 can be closed based on a change in the combustion status in the GCU 12. The combustion status in the GCU 12 is as described above. The valve V51 may also be closed based on the amount of ammonia combusted in the GCU 12. The valve V51 may also be closed based on a change in the gas concentration in the portion C2 of the ship gas line 15.

[0104] The open / close state of each valve after completion of the method for treating residual liquid in the ship side gas line 15 is referred to as the fifth open / close state. The fifth open / close state is as follows: The valves that are open on ship 1 are valves V17, 1V18, and 2V18. The valves that are closed on ship 1 are valves V16, V19, V20, V21, V32, V47, V48, V51, 1V15, 2V15, VN17, and VN18. The valves that are open on tanker truck 2 are valves V6, EV1, and EV2. The valves that are closed on tanker truck 2 are valves V1, V2, V3, V5, V12, and V13.

[0105] According to the method for treating the residual liquid in the ship's gas line 15, it is possible to treat the re-liquefied liquefied ammonia remaining in the ship's gas line 15 before refueling with liquefied ammonia. If liquefied ammonia remains in the ship's gas line 15, there is a risk that the liquefied ammonia remaining in the ship's gas line 15 will flow into the operating compressor 22 during refueling with liquefied ammonia. Therefore, before refueling with liquefied ammonia, it is necessary to create a completely gaseous atmosphere inside the ship's gas line 15. By performing such a process before refueling with liquefied ammonia, it is possible to safely refuel liquefied ammonia from the supply-side tank 21 to the ship's tank.

[0106] (5) Method for treating residual liquid in ship side liquid line 14 The bunkering method includes a method for treating residual liquid in ship side liquid line 14. The method for treating residual liquid in ship side liquid line 14 is a method for treating liquefied ammonia formed by re-liquefaction of ammonia gas remaining in ship side liquid line 14. The method for treating residual liquid in ship side liquid line 14 includes steps 5A to 5J, which will be described later.

[0107] Figures 10 and 11 are diagrams for explaining a method for treating residual liquid in the ship side liquid line 14. Figure 10 is a diagram related to steps 5A to 5E. Figure 10 is a diagram related to steps 5F to 5J. The open / closed state of each valve before starting the method for treating residual liquid in the ship side liquid line 14 is the fifth open / closed state described above.

[0108] (Step 5A) The valve V21 is opened. By opening the valve V21, the state between the ship side liquid line 14 and the ship side gas line 15 is changed from a non-communication state to a communication state.

[0109] (Step 5B) Valve V20 is opened.

[0110] (Step 5C) The valve V19 is opened. By opening the valve V19, the ship side gas line 15 is established in communication with the ship side tank. The ship side gas line 15 is in communication with the portion D1 of the supply side gas line 24 described above.

[0111] (Step 5D) Valve V16 is opened. The portion of the ship side liquid line 14 that communicates from the first end 141 to the closed valves 1V15 and 2V15 is referred to as portion A2. Portion A2 of the ship side liquid line 14 is a portion that is not in communication with the ship side tank, separated by the closure of valves 1V15 and 2V15. Portion A2 of the ship side liquid line 14 is a portion that is in communication with portion B1 of the supply side liquid line 23 described above. Portion A2 of the ship side liquid line 14 is an example of the ship side liquid line 14. By opening valve V16, portion A2 of the ship side liquid line 14 is formed.

[0112] (Step 5E) It is confirmed that the state of communication is established between the ship's side tank, the ship's side gas line 15, and the portion A2 of the ship's side liquid line 14. When the state of communication is established, ammonia gas generated in the ship's side tank flows from the ship's side tank via the ship's side gas line 15 and the connecting line 16 to the portion A2 of the ship's side liquid line 14. When the state of communication is established, the pressures measured in the first ship's side tank 11-1, the second ship's side tank 11-2, the ship's side gas line 15, and the portion A2 of the ship's side liquid line 14 will be the same. By checking the pressure values, it is possible to confirm that the state of communication is established between the ship's side tank, the ship's side gas line 15, and the portion A2 of the ship's side liquid line 14.

[0113] (Step 5F) Valve 1V18 is closed.

[0114] (Step 5G) Valve 2V18 is closed.

[0115] The portion of the ship side gas line 15 that is connected from the first end 151 to the closed valves 1V18 and 2V18 is referred to as portion C3. The portion C3 of the ship side gas line 15 is a portion that is not connected to the ship side tank. The portion C3 of the ship side gas line 15 is a portion that is connected to the portion D1 of the supply side gas line 24 described above. The portion C3 of the ship side gas line 15 is an example of the ship side gas line 15.

[0116] Closing the valve 1V18 in step 5F and closing the valve 2V18 in step 5G forms the portion C3 of the ship side gas line 15. This changes the state between the portion A2 of the ship side liquid line 14 and the ship side tank from a connected state to a disconnected state.

[0117] (Step 5H) Valves V47 and V48 are opened. By opening valves V47 and V48, the state between portion A2 of the ship side liquid line 14 and the GCU 12 is changed from a non-communication state to a communication state. The liquefied ammonia remaining in portion A2 of the ship side liquid line 14 flows from portion A2 of the ship side liquid line 14 to the GCU 12. The liquefied ammonia may vaporize in the process of flowing from portion A2 of the ship side liquid line 14 to the GCU 12.

[0118] (Step 5I) The ammonia that has flowed from the portion A2 of the ship side liquid line 14 to the GCU 12 is combusted in the GCU 12. The GCU 12 can combust ammonia gas that has been vaporized from the liquefied ammonia in the process of flowing from the portion A2 of the ship side liquid line 14 to the GCU 12. The GCU 12 can combust the ammonia gas after vaporizing the liquefied ammonia that has flowed from the portion A2 of the ship side liquid line 14 to the GCU 12.

[0119] (Step 5J) After the valves V47 and V48 are opened and the ammonia flowing from the portion A2 of the ship's liquid line 14 to the GCU 12 is combusted by the GCU 12, the valves V47 and V48 are closed. Closing the valves V47 and V48 changes the state between the portion A2 of the ship's liquid line 14 and the GCU 12 from a connected state to a disconnected state. For example, the valves V47 and V48 can be closed based on the pressure of the ammonia gas supplied to the GCU 12. The combustion of the ammonia gas by the GCU 12 reduces the pressure of the ammonia gas. Therefore, the decrease in the pressure of the ammonia gas indicates that the amount of liquefied ammonia remaining in the portion A2 of the ship's liquid line 14 is decreasing. The pressure threshold used as a guide for closing the valves V47 and V48 can be set as appropriate. The valves V47 and V48 may also be closed based on the amount of ammonia combusted by the GCU 12. The valves V47 and V48 may be closed based on a change in the combustion state in the GCU 12. The combustion state in the GCU 12 is as described above. The valves V47 and V48 may be closed based on a change in the gas concentration in the portion A2 of the ship side liquid line 14.

[0120] The open / closed state of each valve after completion of the method for treating residual liquid in the ship side liquid line 14 will be referred to as the sixth open / closed state. The sixth open / closed state is as follows: The valves that are open on ship 1 are valves V16, V17, V19, V20, and V21. The valves that are closed on ship 1 are valves V32, V47, V48, V51, valve 1V15, valve 2V15, valve 1V18, valve 2V18, valve VN17, and valve VN18. The valves that are open on tanker truck 2 are valves V6, EV1, and EV2. The valves that are closed on tanker truck 2 are valves V1, V2, V3, V5, V12, and V13.

[0121] According to the method for treating the residual liquid in the side liquid line 14, the reliquefied liquefied ammonia remaining in the side liquid line 14 can be treated before liquefied ammonia is replenished. Reliquefied liquefied ammonia often contains impurities, but the method for treating the residual liquid in the side liquid line 14 can treat such liquefied ammonia. The method for treating the residual liquid in the side liquid line 14 can create a completely gaseous atmosphere inside the side liquid line 14. This can remove impurities such as ammonia in the side liquid line 14 as well as air, moisture, and nitrogen, preventing them from entering the side tanks and freezing inside the side liquid line 14. Furthermore, by passing ammonia gas through the side liquid line 14, it is possible to confirm that there is no leakage from the side liquid line 14 before replenishment of liquefied ammonia. This process before replenishment of liquefied ammonia allows liquefied ammonia to be safely replenished from the supply tank 21 to the side tank.

[0122] (6) Replenishment Preparation Method The bunkering method includes a replenishing preparation method. The replenishing preparation method is a method for preparing to replenishing liquefied ammonia from the supply-side tank 21 to the ship-side tank. The replenishing preparation method includes steps 6A to 6G, which will be described later.

[0123] 12 is a diagram for explaining the replenishment preparation method. Before the replenishment preparation method is started, the open / close states of the valves are the sixth open / close states described above.

[0124] (Step 6A) The valve V21 is closed. By closing the valve V21, the state between the portion A2 of the ship side liquid line 14 and the portion C3 of the ship side gas line 15 is changed from a communication state to a non-communication state.

[0125] (Step 6B) Valve 1V18 is opened.

[0126] (Step 6C) Valve 2V18 is opened.

[0127] By opening the valve 1V18 in step 6B and the valve 2V18 in step 6C, the state between the portion D1 of the supply side gas line 24 and the ship's tank is changed from a non-communicative state to a communicative state. The ship's side gas line 15 connects the portion D1 of the supply side gas line 24 and the ship's tank in a communicative state.

[0128] (Step 6D) Valve V2 is opened.

[0129] Opening the valve V2 changes the state between the supply side tank 21 and the ship side gas line 15 from a non-communication state to a communication state. The supply side gas line 24 connects the supply side tank 21 and the ship side gas line 15 in a communication state.

[0130] By steps 6B, 6C, and 6D, the state between the supply side tank 21 and the ship side tank changes from a non-communication state to a communication state along the ship side gas line 15 and the supply side gas line 24.

[0131] (Step 6E) Valves V1 and V3 are opened.

[0132] Opening the valves V1 and V3 changes the state between the supply tank 21 and the portion A2 of the ship side liquid line 14 from a non-communication state to a communication state. The supply side liquid line 23 connects the supply tank 21 and the portion A2 of the ship side liquid line 14 in a communication state.

[0133] (Step 6F) Valve 1V15 is opened.

[0134] (Step 6G) Valve 2V15 is opened.

[0135] By opening the valve 1V15 in step 6F and the valve 2V15 in step 6G, the state between the supply side liquid line 23 and the ship's tank is changed from a non-communicative state to a communicative state. The ship's liquid line 14 connects the supply side liquid line 23 and the ship's tank in a communicative state.

[0136] By steps 6E, 6F and 6G, the state between the supply side tank 21 and the ship side tank changes from a non-communication state to a communication state along the ship side liquid line 14 and the supply side liquid line 23.

[0137] Due to the replenishment preparation method, the supply-side tank 21 and the ship's tank are in a state of communication through the ship's side gas line 15 and the supply-side gas line 24. Therefore, ammonia gas generated in the ship's tank can flow to the supply-side tank 21 via the ship's side gas line 15 and the supply-side gas line 24. Due to the replenishment preparation method, the supply-side tank 21 and the ship's tank are in a state of communication through the ship's side liquid line 14 and the supply-side liquid line 23. Therefore, liquefied ammonia stored in the supply-side tank 21 can flow to the ship's side tank via the ship's side liquid line 14 and the supply-side liquid line 23.

[0138] The open / closed state of each valve after the completion of the replenishment preparation method will be referred to as the seventh open / closed state. The seventh open / closed state is as follows: The valves that are open on Ship 1 are Valve V16, Valve V17, Valve V19, Valve V20, Valve 1V15, Valve 2V15, Valve 1V18, and Valve 2V18. The valves that are closed on Ship 1 are Valve V21, Valve V32, Valve V47, Valve V48, Valve V51, Valve VN17, and Valve VN18. The valves that are open on Tanker Truck 2 are Valve V1, Valve V2, Valve V3, Valve V6, Valve EV1, and Valve EV2. The valves that are closed on Tanker Truck 2 are Valve V5, Valve V12, and Valve V13.

[0139] According to the replenishment preparation method, before replenishment of liquefied ammonia, the ship's liquid line 14 can be adjusted so that liquefied ammonia is sent from the supply-side tank 21 to the ship's tank, and the ship's gas line 15 can be adjusted so that ammonia gas is sent from the ship's tank to the supply-side tank 21. As a result, during replenishment of liquefied ammonia, the ammonia gas is sent from the ship's tank to the supply-side tank 21. By performing such a process before replenishment of liquefied ammonia, liquefied ammonia can be safely replenished from the supply-side tank 21 to the ship's tank.

[0140] (7) Method for replenishment of second ship's side tank 11-2 The bunkering method includes a method for replenishment of the second ship's side tank 11-2. The method for replenishment of the second ship's side tank 11-2 is a method for replenishment of liquefied ammonia from the supply-side tank 21 to the second ship's side tank 11-2. The method for replenishment of the second ship's side tank 11-2 includes steps 7A to 7K, which will be described later.

[0141] 13 is a diagram for explaining a method for replenishing the second ship tank 11-2. Before starting the method for replenishing the second ship tank 11-2, the open / close states of the valves are the seventh open / close state described above.

[0142] (Step 7A) Notify each location that replenishment to the ship's tanks has begun. Announce the planned amount of fuel in the ship's tanks after replenishment.

[0143] (Step 7B) The valve 1V15 is closed. Closing the valve 1V15 changes the state between the supply-side liquid line 23 and the first ship's tank 11-1 from a connected state to a disconnected state. As a result, the state between the supply-side tank 21 and the first ship's tank 11-1 changes from a connected state to a disconnected state along the ship's liquid line 14 and the supply-side liquid line 23.

[0144] (Step 7C) Valve V6 is closed.

[0145] (Step 7D) Valve V12 is opened.

[0146] (Step 7E) Valve V13 is opened.

[0147] Steps 7C, 7D, and 7E change the flow path of the ammonia gas in the supply-side gas line 24. The flow path of the ammonia gas changes from a path in which the ammonia gas from the ship's tank enters the supply-side tank 21 without passing through the compressor 22 to a path in which the ammonia gas enters the supply-side tank 21 via the compressor 22.

[0148] (Step 7F) The compressor 22 is started. The ammonia gas compressed by the compressor 22 pressurizes the supply-side tank 21. The pressure in the supply-side tank 21 becomes higher than the pressure in the ship's tank. Therefore, the liquefied ammonia stored in the supply-side tank 21 is pressure-transferred to the ship's tank via the supply-side liquid line 23 and the ship's liquid line 14.

[0149] (Step 7G) ​​It is confirmed that the state of communication is established between the ship's side tank, the ship's side liquid line 14, and the ship's side gas line 15. If the state of communication is established, the pressures measured in the first ship's side tank 11-1, the second ship's side tank 11-2, the ship's side liquid line 14, and the ship's side gas line 15 will rise at the same rate. For example, the amount of increase is about 0.2 MPaG, but is not limited to this. By checking the pressure values, it is possible to confirm that the state of communication is established between the ship's side tank, the ship's side liquid line 14, and the ship's side gas line 15.

[0150] (Step 7H) Confirm that there is no leakage of liquefied ammonia from any ruptures or the like in the hose portion of the supply side liquid line 23 (from the valve V1 to the end connected to the ship's side liquid line 14). Confirm that there is no leakage of liquefied ammonia from the connection portion between the first end 141 of the ship's side liquid line 14 and the end of the supply side liquid line 23. Confirm that there is no leakage of ammonia gas from any ruptures or the like in the hose portion of the supply side gas line 24 (from the valve V2 to the end connected to the ship's side gas line 15). Confirm that there is no leakage of ammonia gas from the connection portion between the first end 151 of the ship's side gas line 15 and the end of the supply side gas line 24. For example, a gas detector or the like can be used to confirm leakage. Note that a manifold pressure gauge may also be used to confirm leakage.

[0151] (Step 7I) The compressor 22 is operated to increase the pressure in the supply tank 21 to a first pressure value. For example, the first pressure value is 0.35 MPa, but is not limited to this. The first pressure value can be changed as appropriate.

[0152] (Step 7J) Check that the tank level in the supply tank 21 starts to rise. Check that there are no leaks, as in step 7H. Check that there is no sudden pressure rise due to vaporization of liquefied ammonia in the second ship's tank 11-2.

[0153] (Step 7K) The compressor 22 is operated to increase the pressure in the supply tank 21 to a second pressure value that is higher than the first pressure value. For example, the second pressure value is 0.5 MPa, but is not limited to this. The second pressure value can be changed as appropriate.

[0154] The open / closed state of each valve after the method of replenishment of the second ship's side tank 11-2 is completed will be referred to as the eighth open / closed state. The eighth open / closed state is as follows: The valves that are open on ship 1 are valves V16, V17, V19, V20, valve 2V15, valve 1V18, and valve 2V18. The valves that are closed on ship 1 are valves V21, V32, V47, V48, V51, valve 1V15, valve VN17, and valve VN18. The valves that are open on tanker truck 2 are valves V1, V2, V3, V12, V13, valve EV1, and valve EV2. The valves that are closed on tanker truck 2 are valves V5 and V6.

[0155] According to the method of replenishment of the second ship's side tank 11-2, the pressure of the supply-side tank 21 can be maintained higher than that of the second ship's side tank 11-2 by the operation of the compressor 22 during liquefied ammonia replenishment. As a result, the liquefied ammonia in the supply-side liquid line 23 and the ship's side liquid line 14 is sent to the second ship's side tank 11-2 by ammonia gas compressed by the compressor 22. In this way, the liquefied ammonia can flow from the supply-side tank 21 to the second ship's side tank 11-2. The compressor 22 can increase the pressure of the supply-side tank 21 in stages. This can prevent a sudden increase in the pressure of the second ship's side tank 11-2 due to vaporization of the liquefied ammonia in the second ship's side tank 11-2. By performing such a process during liquefied ammonia replenishment, liquefied ammonia can be safely replenished from the supply-side tank 21 to the ship's side tank.

[0156] (8) Method for Switching Ship's Side Tank The bunkering method includes a method for switching ship's side tank. The method for switching ship's side tank is a method for switching the ship's side tank that supplies liquefied ammonia from the supply-side tank 21 from the second ship's side tank 11-2 to the first ship's side tank 11-1. The method for switching ship's side tank includes steps 8A to 8C, which will be described later. During steps 8A to 8C, the compressor 22 continues to operate to compress the ammonia gas.

[0157] 14 is a diagram for explaining a method for switching the ship's tanks. Before the start of the method for switching the ship's tanks, the open / closed states of the valves are the above-mentioned eighth open / closed state.

[0158] (Step 8A) The valve 1V15 is opened just before the second ship's side tank 11-2 reaches the planned amount of liquefied ammonia to be loaded. For example, just before the planned amount may be 2% of the planned amount, but is not limited to this.

[0159] Opening the valve 1V15 changes the state between the supply-side liquid line 23 and the first ship's side tank 11-1 from a non-communication state to a communication state. As a result, the state between the supply-side tank 21 and the first ship's side tank 11-1 changes from a non-communication state to a communication state along the ship's side liquid line 14 and the supply-side liquid line 23. The liquefied ammonia in the supply-side liquid line 23 and the ship's side liquid line 14 is sent to the first ship's side tank 11-1 by the ammonia gas compressed by the compressor 22. In this way, the liquefied ammonia can flow from the supply-side tank 21 to the first ship's side tank 11-1.

[0160] (Step 8B) The valve 2V15 is closed. Closing the valve 2V15 changes the state between the supply-side liquid line 23 and the second ship's side tank 11-2 from a connected state to a disconnected state. As a result, the state between the supply-side tank 21 and the second ship's side tank 11-2 changes from a connected state to a disconnected state along the ship's side liquid line 14 and the supply-side liquid line 23.

[0161] (Step 8C) Completion of the receipt of liquefied ammonia in the second ship's tank 11-2 is announced.

[0162] The open / closed state of each valve after the completion of the method for switching ship's side tanks is referred to as the ninth open / closed state. The ninth open / closed state is as follows: The valves that are open on Ship 1 are Valve V16, Valve V17, Valve V19, Valve V20, Valve 1V15, Valve 1V18, and Valve 2V18. The valves that are closed on Ship 1 are Valve V21, Valve V32, Valve V47, Valve V48, Valve V51, Valve 2V15, Valve VN17, and Valve VN18. The valves that are open on Tank Truck 2 are Valve V1, Valve V2, Valve V3, Valve V12, Valve V13, Valve EV1, and Valve EV2. The valves that are closed on Tank Truck 2 are Valve V5 and Valve V6.

[0163] (9) Top-off Operation Method The bunkering method includes a top-off operation method. The top-off operation method is a method for pushing the liquefied ammonia remaining in the supply side liquid line 23 and the ship side liquid line 14 into the first ship side tank 11-1 by ammonia gas. By the top-off operation method, the liquefied ammonia in the supply side liquid line 23 and the ship side liquid line 14 is sent to the first ship side tank 11-1 by ammonia gas compressed by the compressor 22.

[0164] First to fourth examples of the method for topping up the containers will be described. In the method for topping up the containers, any one of the first to fourth examples may be performed, or multiple examples may be performed in sequence.

[0165] A first example of the topping-up operation method will be described. In the first example, the supply tank 21 continues to be pressurized after the method of switching the ship's tanks, without changing the opening and closing state of the valve of the tank truck 2. The first example includes steps 9A and 9B, which will be described later. During steps 9A to 9C, the compressor 22 continues to compress the ammonia gas.

[0166] 15 is a diagram for explaining a first example of a topping-off operation method. The open / close state of each valve before the start of the first example is the above-mentioned ninth open / close state. Here, as the first example, an operation will be described in which ammonia gas from a ship's tank is pressurized by the compressor 22 while high-pressure gas is supplied to the supply tank 21, and liquefied ammonia remaining in the liquid line is pushed into the ship's tank.

[0167] (Step 9A) An instruction is given to notify when the remaining amount of liquefied ammonia stored in the supply-side tank 21 reaches a predetermined amount and ammonia gas begins to mix with the liquefied ammonia. For example, the predetermined amount is 1 ton, but is not limited to this. The predetermined amount can be changed as appropriate.

[0168] (Step 9B) The liquefied ammonia remaining in the supply-side liquid line 23 and the ship-side liquid line 14 is pushed into the first ship-side tank 11-1 by the ammonia gas. Here, the supply-side tank 21 is pressurized by the ammonia gas compressed by the compressor 22. The pressure in the supply-side tank 21 becomes higher than the pressure in the first ship-side tank 11-1. Therefore, the ammonia gas in the supply-side tank 21 flows into the first ship-side tank 11-1 while pushing out the liquefied ammonia remaining in the supply-side liquid line 23 and the ship-side liquid line 14 due to the pressure difference.

[0169] The open / close state of each valve after the first example of the top-up operation method is the ninth open / close state described above.

[0170] A second example of the topping-off operation method will now be described. The second example is an example in which the operation of the compressor 22 is stopped after switching the ship's tanks. The second example includes steps 9C and 9D, which will be described later.

[0171] 16 is a diagram for explaining a second example of a top-up operation method. The open / close states of the valves before the start of the second example are the above-mentioned ninth open / close state. Here, as the second example, an operation will be described in which ammonia gas in the supply tank 21 is supplied to the liquid line after the compressor 22 has stopped, and the liquefied ammonia remaining in the liquid line is pushed into the ship's tank.

[0172] (Step 9C) As in step 9A, an instruction is given to notify when the remaining amount of liquefied ammonia stored in the supply-side tank 21 reaches a predetermined amount and ammonia gas begins to be mixed into the liquefied ammonia.

[0173] (Step 9D) The liquefied ammonia remaining in the supply side liquid line 23 and the ship side liquid line 14 is pushed into the first ship side tank 11-1 by ammonia gas. Here, valve V3 is closed. Valve V2 is closed. Valves V12 and V13 are closed. Valve V5 is opened. The operation of the compressor 22 is stopped.

[0174] The communicating portion of the supply-side liquid line 23, from the end connected to the ship's side liquid line 14 to the closed valve V3, is referred to as portion B2. Portion B2 of the supply-side liquid line 23 is a portion that is not in communication with the supply-side tank 21, separated by the closure of valve V3. Portion B2 of the supply-side liquid line 23 is an example of a supply-side liquid line 23. By closing valves V3, V2, V12, and V13 and opening valve V5, a communicating path is formed between the supply-side tank 21 and the first ship's side tank 11-1 that can be traced in this order via portion D2 of the supply-side gas line 24, portion B2 of the supply-side liquid line 23, and the ship's side liquid line 14.

[0175] As described above, the compressor 22 is stopped when the pressure in the supply-side tank 21 is sufficiently higher than the pressure in the ship's tank, and the valves V2 and V3 are closed to put the supply-side tank 21 into a pressure-accumulating state. Therefore, when the valve V5 is opened, the ammonia gas in the supply-side tank 21 flows into the first ship's side tank 11-1 while pushing out the liquefied ammonia remaining in the portion B2 of the supply-side liquid line 23 and the ship's side liquid line 14 due to the pressure difference.

[0176] A third example of the topping-off operation method will be described. The third example is an example in which the ammonia gas from the supply tank 21 is compressed by the compressor 22 after the method of switching the ship's tanks. The third example includes steps 9E to 9F, which will be described later. During steps 9E to 9F, the compressor 22 continues to operate to compress the ammonia gas.

[0177] Figure 17 is a diagram for explaining a third example of a topping-up operation method. The open / close state of each valve before the start of the third example is the ninth open / close state described above. Note that the arrangement of the valves and lines in the tank truck 2 differs in some respects from the arrangement in Figure 1. Here, as the third example, an operation will be described in which ammonia gas in the supply-side tank 21 is pressurized by the compressor 22 and supplied to the liquid line, and the liquefied ammonia remaining in the liquid line is pushed into the ship's tank.

[0178] (Step 9E) As in step 9A, an instruction is given to notify when the remaining amount of liquefied ammonia stored in the supply-side tank 21 reaches a predetermined amount and ammonia gas begins to mix with the liquefied ammonia.

[0179] (Step 9F) The liquefied ammonia remaining in the supply side liquid line 23 and the ship side liquid line 14 is pushed into the first ship side tank 11-1 by ammonia gas. Here, valve V3 is closed. Valve V2 is closed. Valve V6 is closed. Valve V5 is opened. The portion of the supply side gas line 24 that communicates from the supply side tank 21 to the closed valve V2 is referred to as portion D3. Portion D3 of the supply side gas line 24 is a portion that passes through the compressor 22. Portion D3 of the supply side gas line 24 is a portion that is in communication with the supply side tank 21. Portion D3 of the supply side gas line 24 is a portion of the path of the ship side gas line 15 that is not in communication with the ship side tank. Portion D3 of the supply side gas line 24 is an example of the supply side gas line 24.

[0180] Closing the valves V2, V3, and V6 and opening the valve V5 forms a communication path between the portion D3 of the supply-side gas line 24 and the first ship-side tank 11-1 that can be traced in this order through the portion B2 of the supply-side liquid line 23 and the ship-side liquid line 14. The compressor 22 compresses the ammonia gas from the supply-side tank 21. The ammonia gas compressed by the compressor 22 flows into the first ship-side tank 11-1 while pushing out the liquefied ammonia remaining in the portion B2 of the supply-side liquid line 23 and the ship-side liquid line 14.

[0181] A fourth example of the topping-off operation method will be described. The fourth example is an example in which ammonia gas from the side tank is compressed by the compressor 22 after the method of switching the side tank. The fourth example includes steps 9G to 9H, which will be described later. During steps 9G to 9H, the compressor 22 continues to operate to compress the ammonia gas.

[0182] Figure 18 is a diagram for explaining a fourth example of a topping-off operation method. The open / close state of each valve before the start of the fourth example is the ninth open / close state described above. Note that the arrangement of the valves and lines in the tank truck 2 differs in some respects from the arrangement in Figure 1. Here, as the fourth example, an operation will be described in which ammonia gas sent from a ship's tank is pressurized by the compressor 22 and supplied to the liquid line without passing through the supply tank 21, and the liquefied ammonia remaining in the liquid line is pushed into the ship's tank.

[0183] (Step 9G) As in step 9A, an instruction is given to notify when the remaining amount of liquefied ammonia stored in the supply-side tank 21 reaches a predetermined amount and ammonia gas begins to mix with the liquefied ammonia.

[0184] (Step 9H) The liquefied ammonia remaining in the supply side liquid line 23 and the ship side liquid line 14 is pushed into the first ship side tank 11-1 by ammonia gas. Here, valve V3 is closed. Valve EV2 is closed. Valve V5 is opened. The communicating portion of the supply side gas line 24 from the end connected to the ship side gas line 15 to the closed valve EV2 is referred to as portion D4. Portion D4 of the supply side gas line 24 is a portion that passes through the compressor 22. Portion D4 of the supply side gas line 24 is a portion that is not in communication with the supply side tank 21, separated by the closure of valve EV2. Portion D4 of the supply side gas line 24 is a portion of the route of the ship side gas line 15 that is in communication with the ship side tank. Portion D4 of the supply side gas line 24 is an example of the supply side gas line 24.

[0185] Closing valves V3 and EV2 and opening valve V5 forms a communication path between portion D4 of the supply gas line 24 and the first ship's side tank 11-1 that can be traced in this order through portion B2 of the supply liquid line 23 and the ship's side liquid line 14. The compressor 22 compresses the ammonia gas from the ship's side tank. The ammonia gas compressed by the compressor 22 flows to the first ship's side tank 11-1 while pushing out the liquefied ammonia remaining in portion B2 of the supply liquid line 23 and the ship's side liquid line 14.

[0186] According to the top-up operation method, during replenishment of liquefied ammonia, the liquefied ammonia remaining in the supply side liquid line 23 and the ship side liquid line 14 can be pushed into the first ship side tank 11-1 by ammonia gas.

[0187] (10) Top-up Work Completion Method The bunkering method includes a top-up work completion method. The top-up work completion method is a method for completing the top-up work method described above. The top-up work completion method includes steps 10A to 10K, which will be described later.

[0188] 19 is a diagram for explaining a top-up operation completion method. Here, as the top-up operation completion method, a method for completing the first example of the top-up operation method described above will be described. The open / closed state of each valve before the start of the top-up operation completion method is the above-mentioned ninth open / closed state.

[0189] (Step 10A) Close the valve 1V15. For example, close the valve 1V15 when the pressure in the supply tank 21 is slightly higher than the pressure in the first ship's side tank 11-1. This is to prevent backflow.

[0190] (Step 10B) The operation of the compressor 22 is stopped.

[0191] (Step 10C) Valve EV2 and valve EV1 are closed.

[0192] (Step 10D) Valve V12 is closed.

[0193] (Step 10E) Valve V13 is closed.

[0194] (Step 10F) Close valve V3. Confirm that valve V6 is closed.

[0195] (Step 10G) Valve V2 is closed.

[0196] (Step 10H) Valve V1 is closed.

[0197] (Step 10I) Valve 1V18 and valve 2V18 are closed.

[0198] (Step 10J) The valves V16 and V19 are closed. Closing the valve V16 forms the portion A1 of the ship side liquid line 14. Closing the valve V19 forms the portion C1 of the ship side gas line 15.

[0199] (Step 10K) Check the ship's tanks, for example, check the pressure and volume of the ship's tanks.

[0200] The open / closed state of each valve after the completion of the top-off operation completion method is referred to as the tenth open / closed state. The tenth open / closed state is as follows: The valves that are open on Ship 1 are Valve V17 and Valve V20. The valves that are closed on Ship 1 are Valve V16, Valve V19, Valve V21, Valve V32, Valve V47, Valve V48, Valve V51, Valve 1V15, Valve 2V15, Valve 1V18, Valve 2V18, Valve VN17, and Valve VN18. No valves are open on Tank Truck 2. They are Valve V1, Valve V2, Valve V3, Valve V5, Valve V6, Valve V12, Valve V13, Valve EV1, and Valve EV2.

[0201] (11) Method for burning gas remaining in a line The bunkering method includes a method for burning gas remaining in a line. The method for burning gas remaining in a line is a method for burning ammonia gas remaining in a line after liquefied ammonia is replenished from the supply-side tank 21 to the ship's tank.

[0202] The method for burning the residual gas in the line includes steps 11A to 11D, which will be described later.

[0203] 20 is a diagram for explaining the method for burning the remaining gas in the lines. The open / close states of the valves before the start of the method for burning the remaining gas in the lines are the tenth open / close state described above.

[0204] (Step 11A) The valve V21 is opened. By opening the valve V21, the state between the portion A1 of the ship side liquid line 14 and the portion C1 of the ship side gas line 15 is changed from a non-communication state to a communication state. This forms the target portion described above.

[0205] (Step 11B) The valve V48 is opened. By opening the valve V48, the state between the target portion and the GCU 12 is changed from a non-communication state to a communication state. The ammonia gas in the target portion flows from the target portion to the GCU 12.

[0206] (Step 11C) Start operation of the GCU 12. The ammonia gas that has flowed from the target portion to the GCU 12 is combusted in the GCU 12.

[0207] (Step 11D) After the valve V48 is opened and the ammonia gas flowing from the target portion to the GCU 12 is combusted in the GCU 12, the valve V48 is closed. Closing the valve V48 changes the state between the target portion and the GCU 12 from a connected state to a disconnected state. For example, the valve V48 can be closed based on a change in the combustion status in the GCU 12. The combustion status in the GCU 12 is as described above. The valve V48 may also be closed based on the amount of ammonia combusted in the GCU 12. The valve V48 may also be closed based on a change in the gas concentration in the target portion.

[0208] The open / close state of each valve after completion of the method for burning remaining gas in a line is referred to as the eleventh open / close state. The eleventh open / close state is as follows: The valves that are open on ship 1 are valves V17, V20, and V21. The valves that are closed on ship 1 are valves V16, V19, V32, V47, V48, V51, valve 1V15, valve 2V15, valve 1V18, valve 2V18, valve VN17, and valve VN18. No valves are open on tanker truck 2. They are valves V1, V2, V3, V5, V6, V12, V13, EV1, and EV2.

[0209] According to the method for burning and treating the remaining gas in the lines, it is possible to treat the ammonia gas remaining in the ship's liquid line 14 and the ship's gas line 15 after the liquefied ammonia is replenished. By performing such a process after the liquefied ammonia is replenished, the N ２ After the purging method, the supply side liquid line 23 and the supply side gas line 24 can be safely disconnected from the ship side liquid line 14 and the ship side gas line 15.

[0210] (12) N in the line ２ Purging method Bunkering method is to purify the N ２ Includes purging method. N in line ２ The purging method is a method for purging ammonia remaining in the line with nitrogen gas after liquefied ammonia is replenished from the supply tank 21 to the ship's tank. ２ The purging method includes steps 12A to 12P.

[0211] 21 and 22 show the N ２ 21 is a diagram for explaining a purging method. FIG. 21 is a diagram related to steps 12A to 12G. FIG. 22 is a diagram related to steps 12H to 12P. N in the line ２ The open / close state of each valve before the start of the purging method is the eleventh open / close state described above.

[0212] (Step 12A) After closing valve V48 in step 11D, valves VN17 and VN18 are opened. By opening valves VN17 and VN18, nitrogen gas is supplied to the target portion from nitrogen gas cylinder 13. Nitrogen gas is supplied to the target portion until the pressure in the target portion reaches or exceeds a third threshold. For example, the third threshold is 0.1 MPaG, but is not limited to this. The third threshold can be set as appropriate.

[0213] (Step 12B) Close the valve VN18. In a specific example, after the pressure in the target portion has reached or exceeded the third threshold due to the supply of nitrogen gas to the target portion, close the valve VN18. Closing the valve VN18 stops the supply of nitrogen gas to the target portion.

[0214] (Step 12C) After supplying nitrogen gas to the target portion, valve V48 is opened. In a specific example, V48 is opened after the pressure in the target portion becomes equal to or greater than the third threshold due to the supply of nitrogen gas to the target portion. Opening valve V48 changes the state between the target portion and GCU 12 from a non-communication state to a communication state. Nitrogen gas in the target portion flows from the target portion to GCU 12. If ammonia gas remains in the target portion, the ammonia gas remaining in the target portion flows from the target portion to GCU 12. If liquefied ammonia remains in the target portion, the liquefied ammonia remaining in the target portion flows from the target portion to GCU 12. The liquefied ammonia may be vaporized in the process of flowing from the target portion to GCU 12. The GCU 12 can combust the nitrogen gas and ammonia gas that have flowed to the GCU 12. The GCU 12 can combust the ammonia gas after vaporizing the liquefied ammonia that has flowed to the GCU 12.

[0215] (Step 12D) Start operation of the GCU 12. The gas that has flowed from the target portion to the GCU 12 is combusted in the GCU 12.

[0216] (Step 12E) After the valve V48 is opened and the gas flowing from the target portion to the GCU 12 is combusted in the GCU 12, the valve V48 is closed. Closing the valve V48 changes the state between the target portion and the GCU 12 from a connected state to a disconnected state. For example, the valve V48 can be closed based on a change in the combustion status in the GCU 12. The combustion status in the GCU 12 is as described above. The valve V48 may also be closed based on the amount of ammonia combusted in the GCU 12. The valve V48 may also be closed based on a change in the gas concentration in the target portion.

[0217] (Step 12F) Open the valve V32. Measure the gas concentration in the target portion. After measuring the gas concentration in the target portion, close the valve V32. For example, the gas concentration in the target portion is an ammonia concentration, but is not limited to this.

[0218] (Step 12G) If the gas concentration in the target portion after closing valve V48 satisfies the second criterion, valves VN17 and VN18 are closed, and the supply of nitrogen gas to the target portion is terminated. For example, the gas concentration in the target portion satisfying the second criterion means, but is not limited to, that the ammonia concentration in the target portion is 25 ppm or less. If the gas concentration in the target portion after closing valve V48 does not satisfy the second criterion, steps 12A to 12G are repeated until the gas concentration in the target portion satisfies the second criterion.

[0219] (Step 12H) Close valve V17 and close valve V20.

[0220] (Step 12I) Valve V47 is opened. The portion of the ship side liquid line 14 that communicates from the closed valve V16 to the closed valves 1V15 and 2V15 is referred to as portion A3. Portion A3 of the ship side liquid line 14 is a portion that is not in communication with the ship side tank, separated by the closure of valves 1V15 and 2V15. Portion A3 of the ship side liquid line 14 is a portion that is not in communication with the ship side gas line 15. Portion A3 of the ship side liquid line 14 is a portion that is not in communication with the supply side liquid line 23. Portion A3 of the ship side liquid line 14 is an example of a ship side liquid line 14.

[0221] Opening valve V47 changes the state between portion A3 of the ship side liquid line 14 and the GCU 12 from a non-communication state to a communication state. The liquefied ammonia remaining in portion A3 of the ship side liquid line 14 flows from portion A3 of the ship side liquid line 14 to the GCU 12. The liquefied ammonia may vaporize in the process of flowing from portion A3 of the ship side liquid line 14 to the GCU 12.

[0222] (Step 12J) The ammonia that has flowed from portion A3 of the ship side liquid line 14 to the GCU 12 is combusted in the GCU 12. The GCU 12 can combust ammonia gas that has been vaporized from the liquefied ammonia in the process of flowing from portion A3 of the ship side liquid line 14 to the GCU 12. The GCU 12 can combust the ammonia gas after vaporizing the liquefied ammonia that has flowed from portion A3 of the ship side liquid line 14 to the GCU 12. The pressure in portion A3 of the ship side liquid line 14 decreases due to the combustion of ammonia by the GCU 12.

[0223] (Step 12K) After the pressure in portion A3 of the ship side liquid line 14 becomes equal to or lower than the fourth threshold, the valve V47 is closed. Closing the valve V47 changes the state between portion A3 of the ship side liquid line 14 and the GCU 12 from a connected state to a disconnected state. For example, the fourth threshold is 0.01 MPaG, but is not limited to this. The fourth threshold can be set as appropriate. The valve V47 may be closed based on a change in the combustion status in the GCU 12. The valve V47 may be closed based on the amount of ammonia combusted in the GCU 12. The valve V47 may be closed based on a change in the gas concentration in portion A3 of the ship side liquid line 14.

[0224] (Step 12L) Monitor the pressure in portion A3 of the ship side liquid line 14. This is because if liquefied ammonia remains in portion A3 of the ship side liquid line 14, the pressure in portion A3 of the ship side liquid line 14 will increase due to the evaporation of the liquefied ammonia.

[0225] (Step 12M) Valve V51 is opened. The portion of the ship side gas line 15 that communicates from the closed valve V19 to the closed valves 1V18 and 2V18 is referred to as portion C4. Portion C4 of the ship side gas line 15 is a portion that is not in communication with the ship side tank, separated by the closure of valves 1V18 and 2V18. Portion C4 of the ship side gas line 15 is a portion that is not in communication with the ship side liquid line 14. Portion C4 of the ship side gas line 15 is a portion that is not in communication with the supply side gas line 24. Portion C4 of the ship side gas line 15 is an example of the ship side gas line 15.

[0226] Opening the valve V51 changes the state between the portion C4 of the ship side gas line 15 and the GCU 12 from a non-communication state to a communication state. The ammonia gas remaining in the portion C4 of the ship side gas line 15 flows from the portion C4 of the ship side gas line 15 to the GCU 12.

[0227] (Step 12N) The ammonia that has flowed from the portion C4 of the ship side gas line 15 to the GCU 12 is combusted by the GCU 12. The GCU 12 can combust the ammonia gas that has flowed from the portion C4 of the ship side gas line 15 to the GCU 12. The pressure in the portion C4 of the ship side gas line 15 decreases due to the combustion of ammonia by the GCU 12.

[0228] (Step 12O) After the pressure in portion C4 of the ship side gas line 15 becomes equal to or lower than the fifth threshold, the valve V51 is closed. Closing the valve V51 changes the state between portion C4 of the ship side gas line 15 and the GCU 12 from a connected state to a disconnected state. For example, the fifth threshold is 0.01 MPaG, but is not limited to this. The fifth threshold can be set as appropriate. The valve V51 may be closed based on a change in the combustion status in the GCU 12. The valve V51 may be closed based on the amount of ammonia combusted in the GCU 12. The valve V51 may be closed based on a change in the gas concentration in portion C4 of the ship side gas line 15.

[0229] (Step 12P) The pressure of the portion C4 of the ship's gas line 15 is monitored. This is because, if re-liquefied liquefied ammonia remains in the portion C4 of the ship's gas line 15, the pressure of the portion C4 of the ship's gas line 15 will increase due to the evaporation of the liquefied ammonia.

[0230] According to the method for burning and treating residual gas in lines, it is possible to treat ammonia remaining in the ship side liquid line 14 and the ship side gas line 15 after replenishment of liquefied ammonia. In particular, it is possible to treat ammonia using nitrogen gas in the portion of the ship side liquid line 14 near the first end 141 and the portion of the ship side gas line 15 near the first end 151. This makes it possible to reduce the ammonia concentration in the portion of the ship side liquid line 14 near the first end 141 and the portion of the ship side gas line 15 near the first end 151 to a level that does not adversely affect the human body. Therefore, it is possible to safely remove the supply side liquid line 23 and the supply side gas line 24 from the ship side liquid line 14 and the ship side gas line 15.

[0231] (Other Embodiments) In the above embodiment, the description has been given using an example of the connection between the ship tank provided on the ship 1 and the supply tank 21 provided on the tank truck 2, but the present invention is not limited to this. The above embodiment can be similarly applied to any connection between any tanks.

[0232] The events that are realized by opening the valves described in the above embodiments may also be realized by closing the valves, depending on the arrangement of each line and each valve, etc. The events that are realized by closing the valves described in the above embodiments may also be realized by opening the valves, depending on the arrangement of each line and each valve, etc. Therefore, the opening and closing of the valves in the above embodiments are examples of valve operation.

[0233] The portion of the ship side liquid line 14 described in the above embodiment includes the meaning of a part of the ship side liquid line 14. The portion of the ship side gas line 15 includes the meaning of a part of the ship side gas line 15. The portion of the supply side liquid line 23 includes the meaning of a part of the supply side liquid line 23. The portion of the supply side gas line 24 includes the meaning of a part of the supply side gas line 24.

[0234] Although the methods of the above embodiments have been described with reference to examples in which they are performed by a person, this is not limiting. Part or all of the methods of the above embodiments may be executed by a processing circuit constituting a computer of the device. The processing circuit includes one or more circuits that execute multiple processes. For example, the circuit is a processor such as a CPU (Central Processing Unit). The processing circuit loads a program stored in a storage device such as an HDD (Hard Disc Drive) included in the device onto a RAM (Random Access Memory). The processing circuit can execute various processes by executing the program loaded onto the RAM.

[0235] The lines in the above embodiment may be distinguished by ordinal numbers. For example, the ship liquid line 14, the ship gas line 15, the connecting line 16, and the combustion line 17 are examples of the first line, the second line, the third line, and the fourth line, respectively.

[0236] The present invention is not limited to the above-described embodiments, and various modifications can be made in the implementation stage without departing from the spirit of the invention. Furthermore, the embodiments may be implemented in appropriate combinations, in which case the combined effects can be obtained. Furthermore, the above-described embodiments include various inventions, and various inventions can be extracted by combining selected elements from the disclosed elements. For example, if the problem can be solved and the desired effect can be obtained even if some elements are deleted from all elements shown in the embodiments, the configuration from which these elements are deleted can be extracted as an invention.

[0237] 1...ship, 2...tank truck, 11-1...first ship's tank, 11-2...second ship's tank, 12...GCU, 13...nitrogen gas cylinder, 14...ship's liquid line, 15...ship's gas line, 16...connecting line, 17...combustion line, 18...nitrogen line, 19...concentration detection line, 21...supply side tank, 22...compressor, 23...supply side liquid line, 24...supply side gas line, 141...first end, 142-1...second end, 142-2...second end, 151...first end, 152-1...second end, 152-2...second end, V1 V2 V3 V5 V6 V12 V13 V16 V17 V19 V20 V21 V32 V47 V48 V51 1V15 2V15 1V18 2V18 VN17 VN18 EV1 EV2...Valve

Claims

1. A ship comprising: a ship's side tank; a combustion unit; a first line for sending liquefied ammonia from a supply side tank to the ship's side tank; a second line for sending ammonia gas from the ship's side tank to the supply side tank; a third line connecting the first line and the second line; and a fourth line connecting at least one of the first line and the second line to the combustion unit.

2. A method used in the ship described in claim 1, comprising: before replenishment of liquefied ammonia from the supply-side tank to the ship's tank, opening a valve provided in the third line so as to change the state between the first line and the second line from a non-communicating state to a communicating state; supplying nitrogen gas to a target section in a communicating state including the first line, the second line, and the third line; and after supplying nitrogen gas to the target section, opening a valve provided in the fourth line so as to change the state between the target section and the combustion section from a non-communicating state to a communicating state.

3. The method according to claim 2, wherein the target portion includes a portion of the first line that is separated by the closure of a valve provided in the first line and that is not in communication with the ship's tank, a portion of the second line that is separated by the closure of a valve provided in the second line and that is not in communication with the ship's tank, and the third line.

4. The method of claim 2, wherein the supplying step includes supplying nitrogen gas to the target portion until the pressure in the target portion is equal to or greater than a first threshold; the opening step includes opening the valve in the fourth line after the pressure in the target portion is equal to or greater than the first threshold; and the method further comprises closing the valve in the fourth line after the pressure in the target portion is equal to or less than a second threshold that is lower than the first threshold.

5. The method of claim 4, further comprising, if the gas concentration in the target portion after closing the valve provided in the fourth line does not satisfy the standard, repeating the supplying, opening the valve provided in the fourth line, and closing the valve provided in the fourth line until the gas concentration in the target portion satisfies the standard.

6. A method used in the ship described in claim 1, comprising, before liquefied ammonia is replenished from the supply-side tank to the ship-side tank, opening a valve provided in the fourth line so as to change the state between the second line and the combustion section from a non-communication state to a communication state.

7. A method used in the ship described in claim 1, comprising: before liquefied ammonia is replenished from the supply-side tank to the ship-side tank, opening a valve provided in the third line to change the state between the first line and the second line from a non-communicating state to a communicating state; and opening a valve provided in the fourth line to change the state between the first line and the combustion section from a non-communicating state to a communicating state.

8. A method used in the ship described in claim 1, comprising: before replenishment of liquefied ammonia from the supply-side tank to the ship's tank, closing a valve provided in the third line to change the state between the first line and the second line from a connected state to a disconnected state; opening a valve provided in the second line to change the state between a gas line connected to the supply-side tank and the ship's tank from a disconnected state to a connected state; and opening a valve provided in the first line to change the state between a liquid line connected to the supply-side tank and the ship's tank from a disconnected state to a connected state.

9. The method according to claim 8, wherein, during replenishment of liquefied ammonia from the supply tank to the ship tank, the liquefied ammonia in the liquid line and the first line is sent to the ship tank by ammonia gas compressed by a compressor.

10. A method used in the ship described in claim 1, comprising: after liquefied ammonia has been replenished from the supply-side tank to the ship-side tank, opening a valve provided in the third line to change the state between the first line and the second line from a connected state to a disconnected state; and opening a valve provided in the fourth line to change the state between the first line and the combustion section from a disconnected state to a connected state.

11. A method used in the ship described in claim 1, comprising: after liquefied ammonia is replenished from the supply-side tank to the ship-side tank, supplying nitrogen gas to a target section including the first line, the second line, and the third line; and after nitrogen gas has been supplied to the target section, opening a valve provided in the fourth line to change the state between the target section and the combustion section from a non-communication state to a communication state.

12. The method of claim 11, further comprising: after opening the valve provided in the fourth line, closing the valve provided in the fourth line; and if the gas concentration in the target portion after closing the valve provided in the fourth line does not satisfy the standard, repeating the supplying, opening the valve provided in the fourth line, and closing the valve provided in the fourth line until the gas concentration in the target portion satisfies the standard.

13. A method for use in the ship described in claim 1, comprising: after liquefied ammonia has been replenished from the supply-side tank to the ship-side tank, opening a valve provided in the fourth line so as to change the state between the first line and the combustion section from a non-communication state to a communication state; and closing the valve provided in the fourth line after the pressure in the first line falls below a threshold value.

14. A method used in the ship described in claim 1, comprising: after liquefied ammonia has been replenished from the supply-side tank to the ship-side tank, opening a valve provided in the fourth line so as to change the state between the second line and the combustion section from a non-communication state to a communication state; and closing the valve provided in the fourth line after the pressure in the second line falls below a threshold value.

15. The method according to any one of claims 6, 7, 10 and 11, further comprising closing a valve provided in the fourth line based on a change in combustion conditions in the combustion section.

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