EP4790306A1

EP4790306A1 - Liquefied hydrogen transfer system, intermediate transfer facility thereof, and purge method

Info

Publication number: EP4790306A1
Application number: EP24885409.3A
Authority: EP
Inventors: Takahiro Kano; Masahiro Takita; Tsutomu Ono
Original assignee: Kawasaki Heavy Industries Ltd; Kawasaki Jukogyo KK
Current assignee: Kawasaki Heavy Industries Ltd; Kawasaki Motors Ltd
Priority date: 2023-10-31
Filing date: 2024-10-11
Publication date: 2026-08-12
Also published as: AU2024374242A1; TW202536333A; WO2025094634A1; KR20260100699A; JP2025075489A

Abstract

A liquefied hydrogen transfer system includes: a first facility including a first tank storing liquefied hydrogen; a second facility including a second tank storing liquefied hydrogen; and an intermediate transfer facility disposed between the first facility and the second facility. The intermediate transfer facility includes: a transfer line that transfers liquefied hydrogen between the first tank and the second tank; a purge line that supplies purge gas to the transfer line; a vent line that exhausts gas containing the purge gas from the transfer line; a branched line that branches from the vent line and merges with the vent line at a downstream position in an exhaust direction from a position of the branch; and a thermometer that is disposed in the branched line and measures a temperature of gas flowing through the branched line.

Description

Technical Field

The present disclosure relates to a liquefied hydrogen transfer system for transferring liquefied hydrogen between a plurality of facilities, an intermediate transfer facility thereof, and a purge method using the system.

Background Art

A transfer system for low-temperature liquefied gas may be constructed between a plurality of liquefied gas facilities, and liquefied gas may be transferred from a liquefied gas storage tank provided in one facility to a tank of another facility. In the transfer system, after transfer, it is necessary to perform hot up for returning a transfer line of liquefied gas from a low temperature at the time of operation to room temperature (for example, Patent Literature 1). In the hot up, purge gas is supplied to the transfer line. Gas remaining in the transfer line is exhausted through a vent line together with the purge gas.
In order to determine completion of hot up, it is necessary to measure a temperature of gas flowing through a vent line. As a method of measuring a gas temperature in a pipe, there is a method of measuring a surface temperature of the pipe with a temperature measuring sensor or an infrared thermometer, but it is desirable to use an insertion type thermometer such as a Bourdon tube type thermometer. In a case of the insertion type thermometer, there is an advantage that electrical equipment for measurement is unnecessary and an equipment can be simplified.
However, in a case where a transfer target is liquefied hydrogen, the situation is different. At present, it is difficult to obtain an insertion type thermometer capable of measuring a temperature range lower than -200°C. In a case where a vent line is formed of a single pipe, frost adheres to a surface of the pipe, and it is difficult to measure a gas temperature with a temperature measuring sensor or an infrared thermometer. Even in a case where a vent line is a double pipe, since a heat insulating layer is interposed, it is difficult to measure a temperature of gas flowing through an inner pipe by measurement from an outer pipe side.

Citation List

Patent Literature

Patent Literature 1: JP 2020-133828 A

Summary of Invention

An object of the present disclosure is to appropriately exhaust gas through a vent line in a system for transferring liquefied hydrogen.
A liquefied hydrogen transfer system according to an aspect of the present disclosure includes: a first facility including a first tank storing liquefied hydrogen; a second facility including a second tank storing liquefied hydrogen; and an intermediate transfer facility disposed between the first facility and the second facility, in which the intermediate transfer facility includes: a transfer line for transferring liquefied hydrogen between the first tank and the second tank; a purge line for supplying purge gas to the transfer line; a vent line for exhausting gas containing the purge gas from the transfer line; a branched line that branches from the vent line and merges with the vent line at a downstream position in an exhaust direction from a position of the branch; and a thermometer that is disposed in the branched line and measures a temperature of gas flowing through the branched line.
An intermediate transfer facility according to another aspect of the present disclosure is an intermediate transfer facility disposed between a first facility including a first tank storing liquefied hydrogen and a second facility including a second tank storing liquefied hydrogen, the intermediate transfer facility including: a transfer line for transferring liquefied hydrogen between the first tank and the second tank; a purge line for supplying purge gas to the transfer line; a vent line for exhausting gas containing the purge gas from the transfer line; a branched line that branches from the vent line and merges with the vent line at a downstream position in an exhaust direction from a position of the branch; and a thermometer that is disposed in the branched line and measures a temperature of gas flowing through the branched line.
A purge method according to still another aspect of the present disclosure is a purge method for purging a transfer line for transferring liquefied hydrogen between a first tank storing liquefied hydrogen and a second tank storing liquefied hydrogen before or after use of a liquefied hydrogen transfer system including the transfer line, a purge line for supplying purge gas to the transfer line, a vent line for exhausting gas from the transfer line, and a branched line that branches from the vent line and merges with the vent line at a position downstream of a position of the branch in an exhaust direction, the purge method including: supplying purge gas to the transfer line; exhausting gas exhausted from the transfer line only through the vent line when the gas is estimated to be at or less than a predetermined threshold temperature; and exhausting gas exhausted from the transfer line via the branched line when the gas is estimated to exceed the threshold temperature, and measuring a temperature of the gas flowing through the branched line with a thermometer.

[Effect of the Invention]

According to the present disclosure, in a system for transferring liquefied hydrogen, gas exhaust through a vent line can be appropriately performed.

Brief Description of Drawings

[FIG. 1] FIG. 1 is a block diagram illustrating a basic configuration of a liquefied hydrogen transfer system according to the present disclosure.
[FIG. 2] FIG. 2 is a block diagram illustrating the liquefied hydrogen transfer system according to a specific embodiment of the present disclosure.
[FIG. 3] FIG. 3 is a process chart showing a procedure of a hot up operation using the liquefied hydrogen transfer system of FIG. 2.
[FIG. 4] FIG. 4 is a block diagram illustrating a hot up operation status.
[FIG. 5] FIG. 5 is a block diagram illustrating a hot up operation status.
[FIG. 6] FIG. 6 is a block diagram illustrating a hot up operation status.
[FIG. 7] FIG. 7 is a process chart showing a procedure of a cool down operation using the liquefied hydrogen transfer system of FIG. 2.

Description of Embodiments

Hereinafter, an embodiment of a liquefied hydrogen transfer system and a liquefied hydrogen transfer method according to the present disclosure will be described in detail with reference to the drawings. The liquefied hydrogen transfer system and method of the present disclosure can be applied to transfer of liquefied hydrogen between various facilities that handle liquefied hydrogen. A transfer scene of liquefied hydrogen may be any of a scene between a land facility and a land facility, a scene between a land facility and a mobile facility, and a scene between a mobile facility and a mobile facility. The mobile facility includes a land transportation facility and a water transportation facility. For example, the transfer system and method of the present disclosure can be applied to transfer of liquefied hydrogen between a liquefied hydrogen production facility and a storage tank of a customer, between a cargo handling terminal or a land transportation container provided with a liquefied hydrogen storage tank and a vessel such as a liquefied hydrogen transport vessel or a hydrogen fuel vessel, between a liquefied hydrogen bunkering vessel and a bunkered vessel, between a hydrogen station and a tanker truck, and the like.

[Basic configuration of liquefied hydrogen transfer system]

FIG. 1 is a block diagram illustrating a liquefied hydrogen transfer system TS1 according to a basic embodiment of the present disclosure. The liquefied hydrogen transfer system TS1 includes a first facility 1, a second facility 2, and an intermediate transfer facility 3. The first facility 1 includes a first tank 11 capable of storing liquefied hydrogen. The second facility 2 includes a second tank 21 capable of storing liquefied hydrogen. The first facility 1 and the second facility 2 are land facilities such as the liquefied hydrogen production equipment and the cargo handling terminal described above, or mobile facilities such as a vessel and a vehicle. The first tank 11 and the second tank 21 are tanks having a multi-shell structure including, for example, an insulation layer formed of a vacuum layer, a heat insulating material layer, or a composite layer of both.
The intermediate transfer facility 3 is a facility disposed between the first facility 1 and the second facility 2. The intermediate transfer facility 3 is a facility that constructs a path for transferring liquefied hydrogen from the first facility 1 to the second facility 2, and conversely, for transferring liquefied hydrogen from the second facility 2 to the first facility 1. The intermediate transfer facility 3 may be a temporary facility. In this case, the intermediate transfer facility 3 is desirably a modularized equipment capable of being transported by a towing vehicle such as a trailer, or an equipment capable of being moved on water by a vessel or the like. Of course, the intermediate transfer facility 3 may be a permanent facility on land.
The intermediate transfer facility 3 includes a transfer line 4, a purge line 5, a vent line 6, a branched line 7 and a thermometer 8. The transfer line 4, the purge line 5, the vent line 6, and the branched line 7 are constituted by pipes capable of transferring a fluid. The pipe can be configured by appropriately selecting a multiple pipe including a heat insulating layer such as a vacuum double pipe, a single pipe covered with a heat insulating material, a simple single pipe, or the like. Further, although not illustrated, an on-off valve that switches between flow of gas and stop of the flow is installed at an appropriate position of the pipe.
The transfer line 4 is a line for transferring liquefied hydrogen between the first tank 11 and the second tank 21. One end of the transfer line 4 is connected to the first tank 11, another end is connected to the second tank 21, and both the tanks 11 and 21 can communicate with each other by the transfer line 4. Most of the transfer line 4 is desirably a vacuum double pipe so that liquefied hydrogen can be transferred while maintaining a liquid phase state.
The purge line 5 is a line for supplying purge gas to the transfer line 4. The purge gas is, for example, hydrogen gas, nitrogen gas, or the like at room temperature. A downstream end of the purge line 5 is connected to the transfer line 4. An upstream end of the purge line 5 is connected to a purge gas cylinder 50. For example, when hot up of the intermediate transfer facility 3 is performed after an operation of the liquefied hydrogen transfer system TS1 is finished, purge gas is supplied from the purge gas cylinder 50 to the transfer line 4.
The vent line 6 is a line for exhausting gas containing the purge gas from the transfer line 4. An upstream end of the vent line 6 is connected to the transfer line 4. A downstream end of the vent line 6 is opened to the atmosphere via a treatment equipment. The vent line 6 is used as a path for removing liquefied hydrogen remaining in the transfer line 4 with purge gas at the time of the hot up. Before an operation of the liquefied hydrogen transfer system TS1 is started, at the time of cool down the transfer line 4 to a temperature at which liquefied hydrogen can be transferred, the vent line 6 is used as a path for discharging air or inert gas present in the transfer line 4. Furthermore, the vent line 6 can be used as a path for discharging a boil-off gas generated by heat input to the first tank 11 or the second tank 21.
The branched line 7 is a bypass path for a part of the vent line 6, and is a pipe in which the thermometer 8 is disposed. The vent line 6 is provided with a branch portion 6A and a merging portion 6B disposed at a downstream position in an exhaust direction of the branch portion 6A. An upstream end of the branched line 7 is connected to the branch portion 6A. A downstream end of the branched line 7 is connected to the merging portion 6B. That is, the branched line 7 is a line that once branches from the vent line 6 and merges with the vent line 6 at a position downstream of the branch position.
The thermometer 8 measures a temperature of gas flowing through the branched line 7. As the thermometer 8, various non-electric or electric thermometers can be used. As a non-electric thermometer, for example, an insertion type thermometer such as a Bourdon tube type thermometer in which a probe is inserted into a pipe of the branched line 7 can be used. As an electric thermometer, a thermocouple, a temperature measuring sensor, or the like can be used. When the non-electric thermometer is used, there is an advantage that electric equipment such as a power supply can be omitted and a facility configuration of the liquefied hydrogen transfer system TS1 can be simplified.
For example, in hot up of a transfer system of liquefied natural gas (LNG), a transfer line can be purged from the beginning using nitrogen gas. However, in hot up of the liquefied hydrogen transfer system TS1 for transferring liquefied hydrogen having cold energy of -253°C, since nitrogen gas is solidified, it is initially necessary to purge the transfer line 4 with hydrogen gas or helium gas. After the temperature rises to a temperature above condensation/solidification temperature of nitrogen, the purge gas is switched to nitrogen gas to purge the transfer line 4.
In the hot up operation, it is required to measure a gas temperature in a vent line that exhausts gas including purge gas. For example, it is determined that hot up is completed by confirming that the gas temperature reaches room temperature. Further, by confirming that the gas temperature exceeds condensation/solidification temperature of nitrogen gas, it is determined to switch purge gas from hydrogen gas to nitrogen gas. However, there is a period during which liquefied hydrogen flows in the vent line in an initial stage of hot up or the like. In a case where a temperature sensor is exposed to cryogenic cold energy held by liquefied hydrogen, the temperature sensor may be damaged. Even without structural damage, measurement accuracy of the thermometer may decrease. Therefore, in a liquefied hydrogen transfer system, protection of a thermometer attached to a vent line and ensuring of temperature measurement accuracy are problems.
A problem in another aspect is simplification of a vent line temperature measurement system. In order to avoid occupation of a cargo handling area, the intermediate transfer facility 3 described above is desirably not a permanent facility, and is configured to perform temporary installation and withdrawal each time cargo handling is performed. In order to facilitate the operation of temporary installation and withdrawal, a non-electric temperature measurement system that does not use a power supply or an electric device is preferably employed. Therefore, it is desirable to use an analog insertion type thermometer such as a Bourdon tube type thermometer instead of electric temperature sensors. However, it is currently difficult to obtain an insertion type thermometer capable of coping with cold energy of liquefied hydrogen. Note that there is also a portable infrared thermometer, but it is not suitable for temperature measurement of a vent line of liquefied hydrogen. That is, with an infrared thermometer, in a case where a vent line is a single pipe, measurement is hindered by frost adhering to a surface, and in a case where a vent line is a double pipe, measurement is hindered by a vacuum layer, and a temperature of gas flowing in a pipe cannot be accurately measured.
The liquefied hydrogen transfer system TS1 of the present embodiment has a configuration capable of solving the above-described problem. Specifically, the liquefied hydrogen transfer system TS1 includes the vent line 6 and the branched line 7 which is a bypass line for a part of the vent line 6 and to which the thermometer 8 is attached. For this reason, gas containing purge gas taken out from the transfer line 4 can be exhausted by two routes including a route passing only through the vent line 6 and a route passing through the branched line 7 with the thermometer 8. Switching of these routes is realized by an operation of an on-off valve (not illustrated) arranged in the intermediate transfer facility 3.
A method of purging the transfer line 4 of the liquefied hydrogen transfer system TS1 will be exemplified. In a case of a hot up operation, purge gas is supplied from the purge line 5 to the transfer line 4. As the purge gas, for example, hydrogen gas at room temperature is used at the beginning of hot up, and nitrogen gas is used after a temperature of the transfer line 4 rises to a temperature at which nitrogen gas can be supplied. The purge gas cylinder 50 to be used is switched so as to cope with the switching of the purge gas.
Whether to use the route passing only through the vent line 6 or the route passing through the branched line 7 in exhaust of purge gas depends on temperature of gas introduced into the vent line 6. When it is estimated that gas exhausted from the transfer line 4 has a low temperature equal to or less than a predetermined threshold temperature, the gas is exhausted only through the vent line 6. The threshold temperature can be appropriately set in consideration of a temperature at which the thermometer 8 is not damaged.
On the other hand, when it is estimated that gas exhausted from the transfer line 4 exceeds the threshold temperature, the gas is exhausted via the branched line 7. A timing at which the temperature exceeds the threshold temperature can be roughly identified by thermal calculation in consideration of the volume of a pipe including the transfer line 4, an amount of hydrogen gas supplied from the purge line 5 per unit time, and supply time.
When the exhaust is switched to the exhaust in the route passing through the branched line 7, a temperature of gas flowing through the branched line 7 is measured by the thermometer 8. When it is confirmed by a measurement value of the thermometer 8 that the gas temperature exceeds a condensation/solidification point of nitrogen gas, purge gas is switched from hydrogen gas to nitrogen gas. That is, nitrogen gas is supplied from the purge line 5 to the transfer line 4. Exhaust via the branched line 7 may be performed as it is until completion of hot up. In a case where cold energy remains in a bypassed portion of the vent line 6, switching to the exhaust by the route passing only through the vent line 6 may be performed.
As described above, according to the liquefied hydrogen transfer system TS1, in the hot up processing, it is possible to perform an operation of exhausting gas exhausted from the transfer line 4 through the vent line 6 when temperature of the gas is at a cryogenic temperature and exhausting the gas via the branched line 7 at a timing when the temperature of the gas is assumed to rise. For this reason, a temperature of gas to be purged can be measured using the thermometer 8 that cannot be used in a cryogenic environment in which the thermometer 8 is in contact with liquefied hydrogen. Therefore, even in a case where the transfer line 4 in which liquefied hydrogen remains is purged, temperature of gas sent to the vent line 6 can be accurately grasped.
In a case of a cool down operation performed before the start of use of the liquefied hydrogen transfer system TS1, liquefied hydrogen is supplied from the first tank 11 or the second tank 21 to the transfer line 4. Since the transfer line 4 is at room temperature, most of liquefied hydrogen enters the vent line 6 while being vaporized, and is exhausted. In an initial stage of cool down, since exhausted gas has a relatively high temperature, the gas is exhausted via the route passing through the branched line 7. At this time, a temperature of the gas flowing through the branched line 7 is measured by the thermometer 8. Before the gas temperature becomes lower than a temperature measurable by the thermometer 8, the exhaust route is switched to the route passing only through the vent line 6. By the above operation, the thermometer 8 can be protected from cold energy of liquefied hydrogen.

[Specific embodiment of liquefied hydrogen transfer system]

FIG. 2 is a block diagram illustrating a liquefied hydrogen transfer system TS2 according to a specific embodiment of the present disclosure. The liquefied hydrogen transfer system TS2 includes a transport vessel 10, a container 20, and an intermediate transfer facility 30. The transport vessel 10 corresponds to the first facility 1 illustrated in the basic configuration of FIG. 1, and the container 20 corresponds to the second facility 2. The transport vessel 10 is a vessel that performs water transport of liquefied hydrogen, and includes the first tank 11 capable of storing liquefied hydrogen. A first communication line 101 and a second communication line 102 extend from the first tank 11. The container 20 is a container for land transportation of liquefied hydrogen, and includes the second tank 21 capable of storing liquefied hydrogen and a tank holding frame. A third communication line 201 and a fourth communication line 202 extend from the second tank 21. The container 20 can be towed by a trailer or the like to move on a land road.
The intermediate transfer facility 30 is a facility that constructs a path for transferring liquefied hydrogen from the transport vessel 10 to the container 20 and, conversely, for transferring liquefied hydrogen from the container 20 to the transport vessel 10. The intermediate transfer facility 30 is desirably configured to be capable of being transported by land by a trailer or the like. The intermediate transfer facility 30, similarly to the basic configuration of FIG. 1, includes the transfer line 4, the purge line 5, the vent line 6, the branched line 7 and the thermometer 8. In addition to the above, the intermediate transfer facility 30 of the present embodiment includes a sub-line 9 constituting a purge path.
The transfer line 4 is a line for transferring liquefied hydrogen between the transport vessel 10 and the container 20. A first joint portion J1 is attached to one end of the transfer line 4, and a second joint portion J2 is attached to another end of the transfer line 4. The first joint portion J1 and the second joint portion J2 are terminal portions for pipe connection provided with a flexible hose, a pipe connection coupler, and the like. When a distal end connection portion of the first communication line 101 extending from the transport vessel 10 is connected to the first joint portion J1, the first tank 11 of the transport vessel 10 and the transfer line 4 of the intermediate transfer facility 30 can communicate with each other. When a distal end connection portion of the third communication line 201 extending from the container 20 is connected to the second joint portion J2, the second tank 21 of the container 20 and the transfer line 4 of the intermediate transfer facility 30 can communicate with each other.
The liquefied hydrogen transfer system TS2 includes a first valve 41 to a ninth valve 49 which are a plurality of on-off valves for opening and closing a line. The first valve 41 is disposed on the first communication line 101. The second valve 42 and the third valve 43 are disposed on the transfer line 4. The fourth valve 44 is disposed on the third communication line 201. When liquefied hydrogen is transferred between the transport vessel 10 and the container 20, the first communication line 101 and the third communication line 201 are connected to the transfer line 4, and all of the first valve 41 to the fourth valve 44 are opened. On the other hand, at the time of a purge operation of the transfer line 4 such as hot up, the first valve 41 to the fourth valve 44 are appropriately opened and closed. This point will be described in detail later.
The sub-line 9 is a line parallel to the transfer line 4. A third joint portion J3 is attached to one end of the sub-line 9, and a fourth joint portion J4 is attached to another end of the sub-line 9. When a distal end connection portion of the second communication line 102 extending from the transport vessel 10 is connected to the third joint portion J3, the first tank 11 of the transport vessel 10 and the sub-line 9 can communicate with each other. When a distal end connection portion of the fourth communication line 202 extending from the container 20 is connected to the fourth joint portion J4, the second tank 21 of the container 20 and the sub-line 9 can communicate with each other. The fifth valve 45 is disposed on the second communication line 102. The sixth valve 46 is disposed on the fourth communication line 202. Although the example in which no on-off valve is particularly disposed in the sub-line 9 is illustrated, an on-off valve may be disposed at an appropriate position.
As lines connecting a system of the transfer line 4 and a system of the sub-line 9, a first connection line 91, a second connection line 92, and a third connection line 93 are provided. The first connection line 91 connects the first communication line 101 and the second communication line 102. The seventh valve 47 is disposed on the first connection line 91. The second connection line 92 connects the transfer line 4 and the sub-line 9 in the intermediate transfer facility 30 in the vicinity of the first joint portion J1 and the third joint portion J3. The eighth valve 48 is disposed on the second connection line 92. The third connection line 93 connects the third communication line 201 and the fourth communication line 202. The ninth valve 49 is disposed on the third connection line 93. Note that a line connecting the transfer line 4 and the sub-line 9 may be added in the vicinity of the second joint portion J2 and the fourth joint portion J4 on the container 20 side.
The purge line 5 is a line for supplying purge gas to the transfer line 4. In the present embodiment, hydrogen gas (GH2) and nitrogen gas (GN2) can be supplied as purge gas. A downstream end of the purge line 5 is connected to the transfer line 4 between the second valve 42 and the third valve 43. An upstream end of the purge line 5 branches into a first branch line 5A and a second branch line 5B. A hydrogen gas cylinder 51 for storing hydrogen gas is connected to an upstream end of the first branch line 5A. A nitrogen gas cylinder 52 for storing nitrogen gas is connected to an upstream end of the second branch line 5B.
A first purge valve 53 is disposed in the first branch line 5A. A second purge valve 54 is disposed in the second branch line 5B. In a case where hydrogen gas is used as purge gas, the first purge valve 53 is opened and the second purge valve 54 is closed, and the hydrogen gas is supplied from the hydrogen gas cylinder 51 to the transfer line 4 through the first branch line 5A. In a case where nitrogen gas is used as purge gas, the first purge valve 53 is closed and the second purge valve 54 is opened, and hydrogen gas is supplied from the nitrogen gas cylinder 52 to the transfer line 4 through the second branch line 5B.
The vent line 6 is a line for exhausting gas containing purge gas from the transfer line 4 through the sub-line 9. An upstream end of the vent line 6 is connected to a vent inlet 6C which is a T-branch portion installed in the transfer line 4. The second connection line 92 connects the transfer line 4 and the sub-line 9 between the vent inlet 6C and the third joint portion J3. The vent line 6 is provided with a vent on-off valve 61 that opens and closes the vent line 6. A downstream end of the vent line 6 is connected to a vent stack 62. The vent stack 62 is equipment that dilutes or treats gas purged from the transfer line 4 and releases the gas into the atmosphere.
The branched line 7 is a bypass path for a part of the vent line 6. The vent line 6 is provided with a branch portion 6A and a merging portion 6B disposed at a downstream position in an exhaust direction of the branch portion 6A. An upstream end of the branched line 7 is connected to the branch portion 6A, and a downstream end is connected to the merging portion 6B. The vent on-off valve 61 is disposed in the vent line 6 between the branch portion 6A and the merging portion 6B.
In the branched line 7, the thermometer 8, an upstream valve 71 (first on-off valve), and a downstream valve 72 (second on-off valve) are disposed. The thermometer 8 measures a temperature of gas flowing through the branched line 7. The upstream valve 71 is an on-off valve arranged upstream of an arrangement position of the thermometer 8 in the branched line 7. The downstream valve 72 is an on-off valve arranged downstream of an arrangement position of the thermometer 8. By opening the vent on-off valve 61 and closing the upstream valve 71, gas containing purge gas is exhausted only through the vent line 6. On the other hand, by closing the vent on-off valve 61 and opening the upstream valve 71 and the downstream valve 72, the gas can be exhausted via the branched line 7. Further, by closing the upstream valve 71 and the downstream valve 72, the thermometer 8 can be isolated from the vent line 6. That is, it is possible to prevent cold energy of liquefied hydrogen from reaching the thermometer 8.
When liquefied hydrogen is transferred from the container 20 to the transport vessel 10, only the first valve 41, the second valve 42, the third valve 43, and the fourth valve 44 are opened. The container 20 includes an evaporator that vaporizes a part of stored liquefied hydrogen. Hydrogen gas vaporized by the evaporator is supplied to a gas phase portion of the second tank 21 included in the container 20 to increase pressure of the gas phase portion, so as to send liquefied hydrogen to the third communication line 201. Note that the configuration may be such that hydrogen gas is supplied from the hydrogen gas cylinder 51 to the gas phase portion of the second tank 21. Liquefied hydrogen that is sent out is transferred to the first tank 11 of the transport vessel 10 through the transfer line 4 and the first communication line 101. Transfer of liquefied hydrogen from the transport vessel 10 to the container 20 is similarly performed. Before and after or during the transfer, boil-off gas generated in the first tank 11 of the transport vessel 10 may be discharged through the second communication line 102 and the vent line 6.
After transfer of liquefied hydrogen, a hot up operation of returning a pipe of the intermediate transfer facility 30 including the transfer line 4 from a low temperature during operation to room temperature is performed. Further, before transfer of liquefied hydrogen, a cool down operation of cooling the transfer line 4 to a temperature at which liquefied hydrogen can flow is performed. These operations involve purging of the transfer line 4. Hereinafter, an example of these operations will be described.

[Specific example of hot up operation]

FIG. 3 is a process chart showing a procedure of a hot up operation using the liquefied hydrogen transfer system TS2 of FIG. 2. FIGS. 4 to 6 are block diagrams illustrating a hot up operation status. In FIGS. 4 to 6, a valve drawn in black indicates "closed", and a valve drawn in white indicates "open".
After transfer of liquefied hydrogen, as illustrated in FIG. 4, the first valve 41 and the fourth valve 44 are closed. Liquefied hydrogen remains in the transfer line 4. In hot up, the second valve 42, the third valve 43, the seventh valve 47, the eighth valve 48, and the ninth valve 49 are opened. Some of the valves 42, 43, 47, 48, 49 may be closed to partially purge the transfer line 4. In order to isolate the transport vessel 10 and the container 20 from a purge system, the fifth valve 45 and the sixth valve 46 are also closed. With respect to the vent line 6, the vent on-off valve 61 is opened, and the upstream valve 71 and the downstream valve 72 are closed (Step S1). That is, the branched line 7 is closed, and gas containing purge gas is discharged through only the vent line 6.
With respect to the purge line 5, the first purge valve 53 is opened, and the second purge valve 54 is closed. That is, as indicated by an arrow A1 in FIG. 4, hydrogen gas at room temperature is supplied as purge gas from the hydrogen gas cylinder 51 to the transfer line 4 through the first branch line 5A and the purge line 5 (Step S2).
Supply of purge gas forms a purge gas flow that passes through the third valve 43 into the third connection line 93 and through the ninth valve 49 into the sub-line 9, as indicated by an arrow A2. Further, as indicated by an arrow A3, a purge gas flow is formed which passes through the second valve 42 into the first connection line 91 and through the seventh valve 47 into the sub-line 9. In a case where the eighth valve 48 is opened, a purge gas flow passing through the second connection line 92 is formed. Either one of the seventh valve 47 and the eighth valve 48 may be opened and the other may be closed, and purge including the first joint portion J1 and the third joint portion J3 may be performed, or only the inside of the intermediate transfer facility 30 may be purged. As indicated by an arrow A4, gas introduced into the sub-line 9 flows through the vent line 6, is detoxified by the vent stack 62, and then is released into the atmosphere. Note that since the downstream valve 72 is closed, even if cryogenic gas flows backward from the merging portion 6B of the vent line 6 to the branched line 7, the thermometer 8 is not exposed to the gas.
As a purge method, a publicly-known method such as blow purge or pressure swing can be employed. In a case of blow purge, by continuously supplying purge gas to the transfer line 4, liquefied hydrogen remaining in the transfer line 4 is discharged to the vent line 6. In a case of pressure swing, pressurization to fill a pipe including the transfer line 4 as a closed space with purge gas, and pressure reduction to open the closed space are repeated. In the present embodiment, the vent on-off valve 61 is closed to perform the pressurization, and after filling with purge gas is performed, the vent on-off valve 61 is opened to perform the pressure reduction.
Next, it is determined whether or not predetermined time elapses after the start of supply of hydrogen gas as purge gas (Step S3). The predetermined time is time during which temperature of gas introduced from the transfer line 4 to the vent line 6 is estimated to rise to a temperature at which the thermometer 8 is not damaged, for example, -200°C or more. This time can be roughly identified by heat balance calculation with reference to volume of a pipe including the transfer line 4 and the sub-line 9, supply capacity of hydrogen gas at room temperature, and the like, regardless of whether the blow purge or the pressure swing is employed. In a case where the predetermined time does not elapse (NO in Step S3), supply of hydrogen gas continues.
On the other hand, in a case where the predetermined time elapses (YES in Step S3), the vent on-off valve 61 is closed, and the upstream valve 71 and the downstream valve 72 are opened. That is, the branched line 7 is opened, and the vent line 6 is partially closed (Step S4). FIG. 5 illustrates a state of the liquefied hydrogen transfer system TS2 after execution of Step S4. By the valve operation in Step S4, as indicated by an arrow A5, exhausted gas flows through the branched line 7 as bypassing line.
After the above, a temperature of gas flowing through the branched line 7 is measured by the thermometer 8 (Step S5). While supply of hydrogen gas from the hydrogen gas cylinder 51 is continued, it is determined whether or not a gas temperature measured by the thermometer 8 is equal to or more than a predetermined temperature (Step S6). The predetermined temperature is a predetermined temperature as a temperature at which purge gas is switched from hydrogen gas to nitrogen gas. This temperature is set to a temperature at which nitrogen gas is reliably not condensed and solidified. In a case where the temperature is not equal to or more than the predetermined temperature (NO in Step S6), supply of hydrogen gas and temperature measurement of gas are continued.
On the other hand, in a case where a gas temperature is equal to or more than a predetermined temperature (YES in Step S6), as illustrated in FIG. 6, the vent on-off valve 61 is opened and the upstream valve 71 is closed (Step S7). However, the downstream valve 72 is maintained open. This is to prevent gas having cold energy from being trapped in the branched line 7 before and after the thermometer 8. After the valve operation in Step S7, as indicated by an arrow A6, nitrogen gas at room temperature is supplied from the nitrogen gas cylinder 52 as purge gas (Step S8). That is, while the first purge valve 53 is closed, the second purge valve 54 is opened, and nitrogen gas is supplied to the transfer line 4 through the second branch line 5B and the purge line 5. After passing through the transfer line 4 and the sub-line 9 as indicated by the arrows A2 and A3, the purge gas is exhausted only through the vent line 6 as indicated by an arrow A7.
Subsequently, it is determined whether or not purging of the transfer line 4 by nitrogen gas is completed (Step S9). In the determination in Step S9, for example, a supply amount, supply time, and the like of nitrogen gas can be used as determination elements. In a case where nitrogen gas purge is not completed (NO in Step S9), supply of nitrogen gas from the purge line 5 to the transfer line 4 is continued. In a case where the nitrogen gas purge is completed (YES in Step S9), the vent on-off valve 61 and the downstream valve 72 are closed in addition to the upstream valve 71 that is already closed. That is, both the vent line 6 and the branched line 7 are closed (Step S10). After necessary post-processing is performed, the joint portions J1, J2, J3, and J4 are released, and the intermediate transfer facility 30 is removed.

[Specific example of cool down operation]

FIG. 7 is a process chart showing a procedure of a cool down operation using the liquefied hydrogen transfer system TS2 of FIG. 2. In the cool down, the transfer line 4 is gradually cooled using liquefied hydrogen stored in the second tank 21 of the container 20. Alternatively, the transfer line 4 may be cooled using boil-off gas generated by external heat input to liquefied hydrogen stored in the second tank 21. The boil-off gas is stored in a gas phase portion in the second tank 21. Liquefied hydrogen stored in the first tank 11 of the transport vessel 10 or boil-off gas generated by external heat input to stored liquefied hydrogen may be used. Regarding the vent line 6, at the beginning of cool down, exhaust via the branched line 7 is performed. That is, the vent on-off valve 61 is closed, and the upstream valve 71 and the downstream valve 72 of the branched line 7 are opened (Step S21).
Further, valves to be opened are the second valve 42, the third valve 43, the fourth valve 44, and the seventh valve 47. In a case where liquefied hydrogen in the first tank 11 is used, the first valve 41 and the ninth valve 49 are opened instead of the fourth valve 44 and the seventh valve 47. In a case where boil-off gas stored in a gas phase portion of the second tank 21 is used, the sixth valve 46 and the ninth valve 49 are opened instead of the fourth valve 44. The sixth valve 46 is a valve provided to a line communicating with a gas phase portion of the second tank 21. In a case where boil-off gas of the first tank 11 is used, the fifth valve 45 and the ninth valve 49 are opened instead of the fourth valve 44. The fifth valve 45 is a valve provided to a line communicating with a gas phase portion of the first tank 11. As a matter of course, the seventh valve 47 and the ninth valve 49 may be opened to perform cool down including the sub-line 9. The purge line 5 is not used. Therefore, the first purge valve 53 and the second purge valve 54 are closed.
After the valve operation in Step S21 is performed, liquefied hydrogen is supplied from the container 20 to the transfer line 4 (Step S22). Since the transfer line 4 before cool down is at room temperature, most of supplied liquefied hydrogen enters the vent line 6 together with gas in a pipe while being vaporized, and is exhausted via the branched line 7. At the time of this exhaust, a temperature of gas flowing through the branched line 7 is measured by the thermometer 8 (Step S23). In an initial stage of cool down, since exhausted gas has a relatively high temperature, the gas does not cause cold damage to the thermometer 8.
It is determined whether or not a gas temperature measured by the thermometer 8 is equal to or less than a predetermined temperature (Step S24). The predetermined temperature is set to a temperature higher than a lower limit temperature of a use range of the thermometer 8. In a case where the gas temperature is not equal to or less than the predetermined temperature (NO in Step S24), supply of liquefied hydrogen from the container 20 is continued. In a case where the gas temperature is equal to or less than the predetermined temperature (YES in Step S24), the vent on-off valve 61 is opened, and the upstream valve 71 and the downstream valve 72 of the branched line 7 are closed (Step S25). That is, an exhaust route is switched to a route passing only through the vent line 6. With such a valve operation, the thermometer 8 can be protected from cold energy of liquefied hydrogen.
After the above, it is determined whether or not cool down is completed (Step S26). Whether or not cool down is completed can be estimated by thermal calculation based on a supply amount and supply time of liquefied hydrogen. In a case where cool down is not completed (NO in Step S26), supply of liquefied hydrogen from the container 20 is continued. On the other hand, in a case where cool down is completed (YES in Step S26), the vent on-off valve 61 is closed, and both the branched line 7 and the vent line 6 are closed (Step S27). After the above, the first valve 41 is opened, and transfer of liquefied hydrogen from the container 20 to the transport vessel 10 is started.

[Summary of present disclosure]

The specific embodiment described above includes disclosure having a configuration below.
A liquefied hydrogen transfer system according to a first aspect of the present disclosure includes: a first facility including a first tank storing liquefied hydrogen; a second facility including a second tank storing liquefied hydrogen; and an intermediate transfer facility disposed between the first facility and the second facility, in which the intermediate transfer facility includes: a transfer line that transfers liquefied hydrogen between the first tank and the second tank; a purge line that supplies purge gas to the transfer line; a vent line that exhausts gas containing the purge gas from the transfer line; a branched line that branches from the vent line and merges with the vent line at a downstream position in an exhaust direction from a position of the branch; and a thermometer that is disposed in the branched line and measures a temperature of gas flowing through the branched line.
According to the first aspect, gas containing purge gas can be exhausted by two routes including a route passing only through the vent line and a route passing through the branched line to which the thermometer is attached. For this reason, for example, in the hot up processing, it is possible to perform an operation of exhausting the gas through the vent line when the temperature of the gas is at a cryogenic temperature and exhausting the gas via the branched line at a timing when the temperature of the gas is assumed to rise. In this operation, the temperature of gas passing through the branched line can be measured using a thermometer that cannot be used at a cryogenic temperature at which liquefied hydrogen flows, for example, an insertion type thermometer. Therefore, it is possible to provide a transfer system that allows a temperature of gas flowing through the vent line to be accurately grasped even when a transfer target is liquefied hydrogen.
The liquefied hydrogen transfer system according to a second aspect is the liquefied hydrogen transfer system according to the first aspect, in which the thermometer is a non-electric thermometer.
According to the second aspect, a temperature of gas to be exhausted can be measured without using electrical equipment such as a power supply. Therefore, the liquefied hydrogen transfer system can be constructed with a simple facility configuration.
The liquefied hydrogen transfer system according to a third aspect is the liquefied hydrogen transfer system according to the first or second aspect, in which the intermediate transfer facility further includes an on-off valve disposed in the branched line.
According to the third aspect, flow of gas to the branched line and stop of the flow of the gas can be switched by operation of the on-off valve.
The liquefied hydrogen transfer system according to a fourth aspect is the liquefied hydrogen transfer system according to the third aspect, in which the intermediate transfer facility includes, as the on-off valve, a first on-off valve disposed upstream of an arrangement position of the thermometer in the branched line, and a second on-off valve disposed downstream of the arrangement position of the thermometer.
According to the fourth aspect, it is possible to allow gas to flow to the branched line by opening the first on-off valve and the second on-off valve. On the other hand, by closing the first on-off valve, it is possible to prevent gas from flowing into a thermometer arrangement portion of the branched line from a branch portion of the vent line. By closing the second on-off valve, it is possible to prevent backflow of gas from a merging portion of the vent line to the thermometer arrangement portion. Further, by adjusting a timing of closing the second on-off valve, it is possible to prevent low-temperature gas from being trapped in the thermometer arrangement portion of the branched line.
An intermediate transfer facility according to a fifth aspect is an intermediate transfer facility disposed between a first facility including a first tank storing liquefied hydrogen and a second facility including a second tank storing liquefied hydrogen, the intermediate transfer facility including: a transfer line that transfers liquefied hydrogen between the first tank and the second tank; a purge line that supplies purge gas to the transfer line; a vent line that exhausts gas containing the purge gas from the transfer line; a branched line that branches from the vent line and merges with the vent line at a downstream position in an exhaust direction from a position of the branch; and a thermometer that is disposed in the branched line and measures a temperature of gas flowing through the branched line.
According to the fifth aspect, by installing the intermediate transfer facility between the first facility and the second facility, gas containing purge gas can be exhausted in two routes including a route passing only through the vent line and a route passing through the branched line to which the thermometer is attached. For this reason, it is possible to employ an operation of causing the gas to flow to the branched line at a timing when the temperature of the gas rises to some extent and measuring the gas temperature. Therefore, even if a transfer target is liquefied hydrogen, a temperature of gas flowing through the vent line can be accurately grasped.
A purge method according to a sixth aspect is a purge method for purging a transfer line for transferring liquefied hydrogen between a first tank storing liquefied hydrogen and a second tank storing liquefied hydrogen before or after use of a liquefied hydrogen transfer system including the transfer line, a purge line that supplied purge gas to the transfer line, a vent line that exhausts gas from the transfer line, and a branched line that branches from the vent line and merges with the vent line at a position downstream of a position of the branch in an exhaust direction, the purge method including: supplying purge gas to the transfer line; exhausting gas exhausted from the transfer line only through the vent line when the gas is estimated to be at or less than a predetermined threshold temperature; and exhausting gas exhausted from the transfer line via the branched line when the gas is estimated to exceed the threshold temperature, and measuring a temperature of the gas flowing through the branched line with a thermometer.
According to the sixth aspect, it is possible to measure a temperature of gas by diverting the gas to the branched line by using a thermometer that cannot be used at a cryogenic temperature at which liquefied hydrogen flows. Therefore, even if a transfer target is liquefied hydrogen, a temperature of gas flowing through the vent line can be accurately grasped.

Description for reference signs

TS1, TS2: liquefied hydrogen transfer system
1: first facility
10: transport vessel (first facility)
11: first tank
2: second facility
20: container (second facility)
21: second tank
3, 30: intermediate transfer facility
4: transfer line
5: purge line
6: vent line
6A: branch portion
6B: merging portion
61: vent on-off valve
7: branched line
71: upstream valve (first on-off valve)
72: downstream valve (second on-off valve)
8: thermometer
9: sub-line

Claims

A liquefied hydrogen transfer system comprising:
a first facility including a first tank storing liquefied hydrogen;

a second facility including a second tank storing liquefied hydrogen; and

an intermediate transfer facility disposed between the first facility and the second facility,

wherein the intermediate transfer facility includes:
a transfer line that transfers liquefied hydrogen between the first tank and the second tank;

a purge line that supplies purge gas to the transfer line;

a vent line that exhausts gas containing the purge gas from the transfer line;

a branched line that branches from the vent line and merges with the vent line at a downstream position in an exhaust direction from a position of the branch; and

a thermometer that is disposed in the branched line and measures a temperature of gas flowing through the branched line.
The liquefied hydrogen transfer system according to claim 1, wherein the thermometer is a non-electric thermometer.
The liquefied hydrogen transfer system according to claim 1 or 2, wherein the intermediate transfer facility further includes an on-off valve disposed in the branched line.
The liquefied hydrogen transfer system according to claim 3, wherein the intermediate transfer facility includes, as the on-off valve, a first on-off valve disposed upstream of an arrangement position of the thermometer in the branched line, and a second on-off valve disposed downstream of the arrangement position of the thermometer.
An intermediate transfer facility disposed between a first facility including a first tank storing liquefied hydrogen and a second facility including a second tank storing liquefied hydrogen, the intermediate transfer facility comprising:
a transfer line that transfers liquefied hydrogen between the first tank and the second tank;

a purge line that supplies purge gas to the transfer line;

a vent line that exhausts gas containing the purge gas from the transfer line;

a branched line that branches from the vent line and merges with the vent line at a downstream position in an exhaust direction from a position of the branch; and

a thermometer that is disposed in the branched line and measures a temperature of gas flowing through the branched line.
A purge method for purging a transfer line for transferring liquefied hydrogen between a first tank storing liquefied hydrogen and a second tank storing liquefied hydrogen before or after use of a liquefied hydrogen transfer system including the transfer line, a purge line that supplied purge gas to the transfer line, a vent line that exhausts gas from the transfer line, and a branched line that branches from the vent line and merges with the vent line at a position downstream of a position of the branch in an exhaust direction, the purge method comprising:
supplying purge gas to the transfer line;

exhausting gas exhausted from the transfer line only through the vent line when the gas is estimated to be at or less than a predetermined threshold temperature; and

exhausting gas exhausted from the transfer line via the branched line when the gas is estimated to exceed the threshold temperature, and measuring a temperature of the gas flowing through the branched line with a thermometer.