JP7412625B1 - Method for handling cryogenic liquefied gas, cargo handling equipment for cryogenic liquefied gas, and temperature confirmation method in cargo handling equipment for cryogenic liquefied gas - Google Patents

Abstract

[Problem] In cargo handling of liquefied hydrogen, the amount of liquefied hydrogen consumed for the cooling process of cargo handling equipment can be reduced, the load on the equipment can be suppressed, and liquefied hydrogen can be efficiently and stably cooled. to provide cargo handling methods. A cryogenic liquefied gas cargo handling method according to the present disclosure includes a cooling step of cooling piping included in transfer equipment. The cooling step includes a first step of taking out the cryogenic liquefied gas as a liquid from the tank and flowing it through the piping, and after the first step, taking out the cryogenic liquefied gas as a liquid from the tank and passing it through the piping. and a second step of distributing it to. The cryogenic liquefied gas that is the liquid that is distributed in the first step is discharged as a gas from a branch pipe that branches from the main line and has a smaller diameter than the main line. The cryogenic liquefied gas flowing in the second step is not discharged from the branch pipe. [Selection diagram] Figure 1

Description

The present disclosure relates to a cryogenic liquefied gas cargo handling method, a cryogenic liquefied gas cargo handling equipment, and a temperature confirmation method in the cryogenic liquefied gas cargo handling equipment.

Methods and equipment for the handling of liquefied hydrogen, which is a type of cryogenic liquefied gas, are known. This type of technology is described in Patent Document 1, for example.

Patent Document 1 discloses equipment and a method for precooling a liquefied hydrogen transfer system prior to loading or unloading of liquefied hydrogen. Patent Document 1 discloses that at the end of a loading arm, which is land-side equipment in a ship-to-land transfer facility, two on-off valves are provided between a closing flange at the end of the arm and an outboard arm. There is. According to the equipment disclosed in Patent Document 1, when pre-cooling the loading arm by circulating liquefied hydrogen, the nitrogen gas filled at the end of the loading arm and the liquefied hydrogen cannot come into contact through the on-off valve. do not have. This prevents nitrogen cooled by liquefied hydrogen from freezing inside the on-off valve and causing the on-off valve to become stuck.

Patent No. 6418680

When precooling the loading arm in the equipment disclosed in Patent Document 1, the most distal section of the piping of the loading arm is filled with nitrogen gas, and the adjacent section is filled with hydrogen gas. Liquefied hydrogen is filled in the compartments adjacent to the compartments that have been filled. However, Patent Document 1 does not disclose a specific method for introducing and filling liquefied hydrogen into piping.

When pre-cooling the piping of transfer equipment prior to transferring liquefied hydrogen, the temperature of the piping at the start of pre-cooling is often around room temperature. If liquefied hydrogen, which is a cryogenic fluid, flows through such piping, there is a risk that the piping will be damaged due to thermal contraction caused by rapid temperature changes. On the other hand, from the viewpoint of improving the efficiency of cargo handling operations and reducing energy consumption, it is desirable to shorten the time required for precooling and to reduce the amount of liquefied hydrogen used for precooling.

In view of this current situation, one of the purposes of the present disclosure is to reduce the amount of cryogenic liquefied gas consumed for the cooling process of cargo handling equipment during cargo handling of cryogenic liquefied gas, and to reduce the load on the equipment. It is an object of the present invention to provide a cargo handling method for cryogenic liquefied gas, which can efficiently and stably cool the gas while suppressing it. In addition, one of the objectives of the present disclosure is to reduce the amount of cryogenic liquefied gas consumed for the cooling process of cargo handling equipment in cargo handling of cryogenic liquefied gas, and to suppress the load on the equipment and improve efficiency. It is an object of the present invention to provide cargo handling equipment for cryogenic liquefied gas that can perform cooling well and stably.

A cryogenic liquefied gas cargo handling method according to the present disclosure includes a cryogenic liquefied gas cargo handling method in which cryogenic liquefied gas is transferred from a tank containing cryogenic liquefied gas via a transfer facility, in which piping included in the transfer facility is cooled. This includes a cooling process. The cooling step includes a first step of taking out the cryogenic liquefied gas as a liquid from the tank and flowing it through the piping, and after the first step, taking out the cryogenic liquefied gas as a liquid from the tank and passing it through the piping. and a second step of distributing it to. The cryogenic liquefied gas that is the liquid that is distributed in the first step is discharged as a gas from a branch pipe that branches from the main line and has a smaller diameter than the main line. The cryogenic liquefied gas flowing in the second step is not discharged from the branch pipe.

A cargo handling equipment for cryogenic liquefied gas according to the present disclosure includes a tank containing cryogenic liquefied gas, a first pipe having a first end connected to the tank, and a tank located below the first pipe in the vertical direction. a second pipe having a second end connected to the first pipe; a third end of the first pipe opposite to the first end; and an end of the second pipe opposite to the second end. A fourth end is provided, and a third pipe is connected to the third pipe, and a fourth pipe is branched from the middle of the third pipe and has a diameter smaller than that of the third pipe. A first opening/closing mechanism capable of switching the first pipe between a communicating state and a closed state is provided between the first end and the third end of the first pipe. A second opening/closing mechanism is provided between the second end and the fourth end of the second pipe, and is capable of switching the second pipe between a communicating state and a closed state. A third opening/closing mechanism capable of switching the third piping between a communicating state and a closed state is provided downstream of the connecting portion with the first piping and the connecting portion with the second piping in the third piping. It will be done. The fourth pipe is provided with a fourth opening/closing mechanism that can switch the fourth pipe between a communicating state and a closed state. The fourth pipe branches from the third pipe upstream of the third opening/closing mechanism in the third pipe. The first piping, the second piping, and the third piping are constructed of vacuum-insulated double pipes. At least a portion of the fourth pipe does not have a vacuum insulation structure.

A method for checking temperature in cargo handling equipment for cryogenic liquefied gas according to the present disclosure includes:
measuring the piping temperature in a portion of the fourth piping that does not have a vacuum insulation structure;
or A temperature confirmation method in which the temperature is confirmed by visually checking a portion of the fourth pipe that does not have a vacuum insulation structure.

Provided is a cargo handling method for cryogenic liquefied gas that reduces the amount of cryogenic liquefied gas consumed in the cooling process of cargo handling equipment, suppresses the load on the equipment, and enables efficient and stable cooling. . According to the present disclosure, cryogenic liquefied gas cargo handling equipment is capable of reducing the amount of cryogenic liquefied gas consumed in the cooling process of the cargo handling equipment, suppressing the load on the equipment, and performing efficient and stable cooling. , a method for checking the temperature in the cargo handling equipment is provided.

FIG. 1 is a schematic diagram of cargo handling equipment according to an embodiment of the present disclosure. FIG. 2 is a flowchart outlining a cargo handling method according to an embodiment of the present disclosure. FIG. 3 is a graph showing performance data when the cooling step in the cryogenic liquefied gas cargo handling method according to the present disclosure is performed.

[Overview of embodiment]
First, an overview of the cargo handling method and cargo handling equipment according to the present disclosure will be listed and explained.
A cryogenic liquefied gas cargo handling method according to the present disclosure includes a cryogenic liquefied gas cargo handling method in which cryogenic liquefied gas is transferred from a tank containing cryogenic liquefied gas via a transfer facility, in which piping included in the transfer facility is cooled. This includes a cooling process. The cooling step includes a first step of taking out the cryogenic liquefied gas as a liquid from the tank and flowing it through the piping, and after the first step, taking out the cryogenic liquefied gas as a liquid from the tank and passing it through the piping. and a second step of distributing it to. The cryogenic liquefied gas that is the liquid that is distributed in the first step is discharged as a gas from a branch pipe that branches from the main line and has a smaller diameter than the main line. The cryogenic liquefied gas flowing in the second step is not discharged from the branch pipe.

Conventionally, it is known to pre-cool piping of transfer equipment prior to transfer of a low-temperature fluid. When handling liquefied natural gas (LNG), it is known that low-temperature evaporated gas (BOG) generated from LNG tanks installed on ships or on land is passed through pipes, and the pipes are cooled by the cold energy of the BOG. . However, when handling liquefied hydrogen, it has become clear that it is difficult to cool piping using the liquefied hydrogen BOG. Therefore, during cargo handling of liquefied hydrogen, a method of cooling pipes using liquefied hydrogen, which is a liquid, was investigated. However, it has been found that when extremely low temperature liquefied hydrogen is passed through a large-diameter pipe, rapid partial cooling tends to occur, making it difficult to perform appropriate cooling. Further consideration was given in light of this situation.

In the cargo handling method according to the present disclosure, pipes are cooled in two steps using cryogenic liquefied gas. Among these, as the first step, the liquefied gas taken out from the tank containing the cryogenic liquefied gas is passed through the pipe, and this liquefied gas is branched from the main line and is passed through the branch pipe, which has a smaller diameter than the main line, as a gas. Discharge. According to this configuration, since gas is discharged from the branch pipe having a smaller diameter than the main line, it becomes easy to control the amount of cryogenic liquefied gas flowing through the main line. Therefore, temperature control of the main line becomes easy, and rapid cooling of the piping can be avoided. In addition, when flowing cryogenic liquefied gas through pipes, the temperature difference between the lower part of the pipe that is in direct contact with the liquid and the upper part of the pipe that is not in contact with the liquid (piping top-bottom temperature difference) can become excessive. According to the disclosed cargo handling method, cooling can be proceeded while preventing the pipe top-bottom temperature difference from becoming excessive.

The cargo handling method includes a temperature confirmation step at the same time as the first step or after the first step, and in the temperature confirmation step, when it is confirmed that the temperature of the piping is equal to or lower than a predetermined temperature, the cargo handling method includes a temperature confirmation step. Two steps may be initiated. According to this configuration, it is possible to cool the piping more efficiently, and the amount of liquefied hydrogen consumed for cooling is reduced, which is highly effective in shortening the time required for cooling. These allow for more efficient cargo handling of liquefied hydrogen.

In the cargo handling method, the cryogenic liquefied gas may be liquefied hydrogen, and the predetermined temperature may be lower than the liquefaction point temperature of air. The cargo handling method according to the present disclosure is particularly effective in cargo handling of liquefied hydrogen. Further, by transitioning from the first step to the second step using the temperature below the liquefaction point temperature of air as an index, the piping can be cooled more efficiently.

In the cargo handling method, the temperature checking step may be performed by checking the temperature of the branch pipe. Branch pipe temperatures are easier to measure than main line temperatures. By estimating the temperature of the main line from the temperature of the branch pipes, it becomes possible to handle cryogenic liquefied gas with a simpler equipment configuration.

In the cargo handling method, the temperature checking step may be performed by checking the temperature of a portion of the branch pipe that does not have a vacuum insulation structure. Most of the piping in cryogenic liquefied gas transfer equipment is composed of vacuum-insulated piping. On the other hand, the branch pipe may have a portion that does not have a vacuum insulation structure. It is easier to check the temperature of piping in parts that do not have a vacuum insulation structure than in vacuum insulation piping. By checking the temperature of the parts of the branch pipe other than the vacuum-insulated structure, it is possible to check the temperature more easily and quickly, and it becomes possible to handle cryogenic liquefied gas with a simple equipment configuration.

A cargo handling equipment for cryogenic liquefied gas according to the present disclosure includes a tank containing cryogenic liquefied gas, a first pipe having a first end connected to the tank, and a tank located below the first pipe in the vertical direction. a second pipe having a second end connected to the first pipe; a third end of the first pipe opposite to the first end; and an end of the second pipe opposite to the second end. A fourth end is provided, and a third pipe is connected to the third pipe, and a fourth pipe is branched from the middle of the third pipe and has a diameter smaller than that of the third pipe. A first opening/closing mechanism capable of switching the first pipe between a communicating state and a closed state is provided between the first end and the third end of the first pipe. A second opening/closing mechanism is provided between the second end and the fourth end of the second pipe, and is capable of switching the second pipe between a communicating state and a closed state. A third opening/closing mechanism capable of switching the third piping between a communicating state and a closed state is provided downstream of the connecting portion with the first piping and the connecting portion with the second piping in the third piping. It will be done. The fourth pipe is provided with a fourth opening/closing mechanism that can switch the fourth pipe between a communicating state and a closed state. The fourth pipe branches from the third pipe upstream of the third opening/closing mechanism in the third pipe. The first piping, the second piping, and the third piping are constructed of vacuum-insulated double pipes. At least a portion of the fourth pipe does not have a vacuum insulation structure.

According to the cargo handling equipment according to the present disclosure, the cargo handling method described above can be carried out. Further, it is possible to configure cargo handling equipment by combining existing equipment configurations, and it is possible to configure highly reliable cargo handling equipment at a reasonable cost without requiring special equipment.

In the cargo handling equipment according to the present disclosure, the cryogenic liquefied gas may be liquefied hydrogen or liquefied helium. The cargo handling equipment according to the present disclosure is suitable as equipment for storing and transferring liquefied hydrogen or liquefied helium.

In the cargo handling equipment according to the present disclosure, the diameter of the fourth pipe may be 1/4 or less of the diameter of the third pipe. By setting the diameter of the fourth pipe within this range, the amount of liquefied hydrogen flowing through the third pipe, which is the main line, can be controlled more reliably.

The temperature confirmation method according to the present disclosure includes measuring the pipe temperature at a portion of the fourth pipe that does not have a vacuum insulation structure in the cryogenic liquefied gas cargo handling equipment, or measuring the pipe temperature at a portion of the fourth pipe that does not have a vacuum insulation structure. This is a temperature confirmation method in cryogenic liquefied gas cargo handling equipment that confirms the temperature by visually checking the parts that are not present. According to this temperature method, the pipe temperature can be checked quickly and easily. Also, if you check the correlation between the temperature of the fourth pipe and the temperature of the third pipe in advance, you can estimate the temperature of the third pipe by measuring the temperature of the fourth pipe, and the cargo handling of liquefied hydrogen can be done more quickly. It can be done easily.

[Specific example of embodiment]
Next, specific embodiments of the cryogenic liquefied gas cargo handling method and cargo handling equipment according to the present disclosure will be described with reference to the drawings. In the following drawings, the same or corresponding parts are given the same reference numerals, and the description thereof will not be repeated. Note that in this specification, "cryogenic temperature" means a temperature range of 100 K (-173° C.) or lower. Furthermore, in this specification, the source side of the cryogenic liquefied gas is referred to as the "upstream side", and the destination side of the cryogenic liquefied gas is referred to as the "downstream side". In the following example, the side closer to the tank will be referred to as the "upstream side" and the side closer to the ship will be referred to as the "downstream side," but in actual operation, the direction of fluid flow is not limited to these.

The liquefied gas handled by the cryogenic liquefied gas cargo handling method and cargo handling equipment according to the present disclosure includes liquefied hydrogen, liquefied helium, and liquefied deuterium. The cargo handling method and cargo handling equipment according to the present disclosure are suitable for cargo handling of liquefied hydrogen.

FIG. 1 is a schematic diagram of cargo handling equipment according to the present disclosure. Referring to FIG. 1, cargo handling equipment 1 is a cargo handling terminal that includes a tank 10 that accommodates liquefied hydrogen L0 as cryogenic liquefied gas, and transfer equipment 30. The transfer facility 30 is a facility for transferring the liquefied hydrogen L0 contained in the tank 10 to the ship 20, which is an example of external facility. The external equipment is not limited to a ship, and may be a vehicle such as a tank truck or another fixed equipment. The transfer equipment 30 may include a loading arm.

The transfer equipment 30 includes a first pipe 31 that connects to the tank 10 and a second pipe 32 that connects to the tank 10 below the first pipe 31 in the vertical direction. The first end P1 of the first pipe 31 is connected above the liquid level of the liquefied hydrogen L0 in the tank 10. The first pipe 31 is a line for circulating hydrogen gas, which is a gas obtained by evaporating the liquefied hydrogen L0. The second end P2 of the second pipe 32 is connected below the liquid level of the liquefied hydrogen L0 in the tank 10. The second pipe 32 is a line for circulating liquefied hydrogen gas.

The transfer equipment 30 also includes a main line 33 as a third pipe, and a branch pipe 34 as a fourth pipe branching from the main line 33. A third end P3 of the first pipe 31, which is an end opposite to the first end P1, is connected to the main line 33. Further, a fourth end P4 of the second pipe 32, which is an end opposite to the second end P2, is also connected to the main line 33. The main line 33 may be a large diameter pipe. Large-diameter piping is typically piping with a diameter of 4 inches (inner diameter approximately 100 mm) or more. The equipment and method according to the present disclosure are particularly suitable when the main line 33 is a large-diameter pipe. The upper limit of the diameter of the main line 33 is not particularly limited as long as it has the effects according to the present disclosure, but is, for example, 32 inches (inner diameter approximately 800 mm). The branch pipe 34 has a smaller diameter than the main line 33. The branch pipe 34 may have a diameter that is approximately 1/4 or less of the diameter of the main line 33, for example. Although the lower limit of the diameter of the branch pipe 34 is not particularly limited, for example, piping of 1/8 inch (inner diameter about 6.5 mm) or more can be used. Specifically, for example, the equipment can be configured using piping with a diameter of 16 inches (inner diameter approximately 400 mm) as the main line 33 and piping with a diameter of 1 inch (inner diameter approximately 27 mm) as the branch pipe 34.

The main line 33 is a line that connects directly or via another pipe to external equipment to which the liquefied hydrogen is transferred. On the other hand, the branch pipe 34 is a discharge system. The end of the branch pipe 34 may be open or may be connected to various hydrogen gas utilization facilities. Examples of hydrogen gas utilization equipment include fuel cells, power generation equipment, and the like. Further, the branch pipe 34 may also serve as piping for another purpose. For example, the branch pipe 34 is used as an exhaust line in the cargo handling method according to the present disclosure, but can be used as a pipe for transferring liquefied hydrogen when transferring liquefied hydrogen from the tank 10 to a small storage facility. It can be anything.

The tank 10, the first piping 31, the second piping 32, and the main line 33 have a vacuum insulation structure S that is a highly insulation structure. Specifically, the tank 10 is a tank having a vacuum insulation structure. Further, the first pipe 31, the second pipe 32, and the main line 33 are constructed of vacuum heat-insulated double pipes. It is preferable that at least a portion of the branch pipe 34 from the branch part from the main line 33 is constructed of a vacuum-insulated double pipe. It is preferable that the branch pipe 34 has a portion made up of a vacuum-insulated double pipe and a portion made of a single pipe without a vacuum-insulated structure. By having a portion of the branch pipe 34 that does not have a vacuum insulation structure, temperature confirmation, which will be described later, can be easily performed.

The first pipe 31 is equipped with a valve 41 as a first opening/closing mechanism that can switch the first pipe 31 between a communication state (line open) and a closed state (line closed). The second pipe 32 is equipped with a valve 42 as a second opening/closing mechanism capable of switching the second pipe 32 between a communicating state (line open) and a closed state (line closed). The main line 33 is provided with a valve 43 as a third opening/closing mechanism that can switch the main line 33 between a communication state (line open) and a closed state (line closed). The main line 33 is also equipped with a thermometer 51 that measures the temperature of the piping surface of the main line 33. The thermometer 51 includes a thermometer 51a that measures the temperature at the top of the pipe, and a thermometer 51b that measures the temperature at the bottom of the pipe. The valves 41, 42, 43 are preferably provided within the cover of the vacuum insulated double pipe. The branch pipe 34 branches off from the main line 33 upstream of the valve 43 . The branch pipe 34 is equipped with a valve 44 as a fourth opening/closing mechanism capable of switching the branch pipe 34 between a communication state (line open) and a closed state (line closed). The valve 44 has a smaller capacity than the valves 42 and 43. The valve 44 may be provided in a portion of the branch pipe 34 that does not have a vacuum insulation structure, or may be provided in a portion that has a vacuum insulation structure.

A tray 71 is provided vertically below a portion of the branch pipe 34 that does not have a vacuum insulation structure. When liquefied hydrogen flows through the branch pipe 34, the outer peripheral surface of the branch pipe 34 is cooled by the liquefied hydrogen flowing through the branch pipe 34, and air may liquefy on the pipe surface. In this case, by receiving the liquefied air in the tray 71, safety for workers and surrounding equipment can be improved.

FIG. 1 mainly shows the configuration according to the present disclosure, and shows the transfer equipment in a simplified manner. Transfer equipment 30 includes many components not shown. For example, the branch pipe 34 may not be provided at one location, but may be branched from a plurality of locations on the main line. By dividing the main line into sections using a plurality of valves and providing branch pipes in each section, piping can be cooled in each section. Further, a heating mechanism for heating the gas discharged from the branch pipe 34 may be provided near the outlet of the branch pipe 34.

Next, a cargo handling method according to the present disclosure will be explained. Although the equipment for carrying out the cargo handling method according to the present disclosure is not particularly limited, it is suitably carried out, for example, in the cargo handling equipment 1 described above. The cargo handling method according to the present disclosure is characterized by a cooling method implemented in a cargo handling method that transfers liquefied hydrogen L0, which is a cryogenic liquefied gas, from a tank 10 containing liquefied hydrogen L0 via transfer equipment 30. The cargo handling method according to the present disclosure includes a cooling step of cooling the piping, particularly the main line 33, that the transfer equipment 30 has. This cooling step is typically performed as a pre-cooling step prior to loading and unloading of liquid hydrogen.

FIG. 2 is a flowchart showing an overview of the cargo handling method according to the present disclosure. FIG. 2 illustrates a case where cargo handling is carried out in the cargo handling equipment 1 described above, and the valves 41 to 44 in FIG. 2 correspond to the valves 41 to 44 shown in FIG. 1.

Referring to FIG. 2, the cooling process included in the cargo handling method according to the present disclosure includes a first cooling step S1 and a second cooling step S2 performed subsequent to the first cooling step S1.

A cooling process is started (S0). When the cooling process is started, the piping of the transfer equipment 30 may be in an uncooled state (normal temperature range). Furthermore, a preliminary cooling step or a gas replacement step may be performed before the first cooling step S1. For example, as a preliminary cooling step, hydrogen gas may be taken out from the tank 10 through the first pipe 31 and filled in the pipe.

At the start of the first cooling step S1, the valve 41 of the first pipe 31, which is a gas extraction line from the tank 10, and the valve 43 of the main line 33 are fully closed. The valve 42 of the second pipe 32, which is a line for extracting liquefied hydrogen gas from the tank 10, is fully opened (S10). In this way, liquefied hydrogen, which is a liquid, is taken out from the tank and distributed to the piping of the transfer equipment. Next, the valve 44 provided in the branch pipe 34 is repeatedly fully opened and fully closed (S20). The liquefied hydrogen supplied into the pipe is discharged as gas G1 through the branch pipe 34. Furthermore, liquefied hydrogen is drawn into the pipe from the tank 10 according to the amount of gas G1 discharged from the branch pipe 34. Here, the branch pipe 34 has a smaller diameter than the main line 33, and the amount of exhaust from the valve 44 is also small. Therefore, the amount of liquefied hydrogen flowing into the main line 33 can be easily adjusted. As a result, even if the main line 33 has a large diameter, the cooling speed of the main line 33 does not become excessive, and the temperature difference between the top and bottom of the piping of the main line 33 can be suppressed from becoming excessive. In the flowchart shown in FIG. 2, the valve 42 is fully open, but the opening degree of the valve 42 may be changed during the first cooling step S1. For example, the valve 42 may be partially opened from the start to the middle of the first cooling step S1, and after confirming that cooling has progressed to a certain extent, the valve 42 may be fully opened. By changing the opening degree of the valve 42 during the first cooling step S1, the cooling speed can be controlled more precisely. Further, in the flowchart shown in FIG. 2, the valve 44 is repeatedly fully opened and fully closed, but the valve 44 may be partially opened and closed repeatedly.

Each time the valve 44 is fully opened and closed once or multiple times, the temperature between the valves 42 and 43 is checked (S30). Although the specific form of temperature confirmation is not particularly limited, typically, the piping temperature of the main line 33 is confirmed. The thermometer 51 may be used to check the temperature, or the temperature of the main line 33 may be estimated from the temperature of the branch pipe 34. If the temperature between the valves 42 and 43 is -220° C. or higher (NO in S30), repeat S20. If the temperature between the valves 42 and 43 is less than -220° C. (YES in S30), the valve 44 of the branch pipe 34 is fully closed (S40). By opening and closing the valve 44 provided in the branch pipe 34, which is a pipe with a smaller diameter than the main line 33, cooling can be performed while suppressing the cooling speed from becoming excessive. Moreover, cooling can be performed while suppressing an excessive temperature difference between the top and bottom of the main line 33, which is a large-diameter pipe.

In the example shown in FIG. 2, it is confirmed in S30 that the temperature between the valves 42 and 43 is less than -220°C, but this temperature is not limited to -220°C and may vary depending on the configuration of the equipment and the diameter of the piping. A predetermined temperature can be set according to the conditions. The predetermined temperature is preferably equal to or lower than the liquefaction point temperature of air (approximately -190°C). By proceeding with cooling in the first cooling step S1 until the temperature of the main line 33 becomes equal to or lower than the liquefaction point temperature of air, it is possible to prevent the cooling speed from becoming excessive in the subsequent second cooling step S2.

Next, the process proceeds to the second cooling step S2. The valve 44 provided in the branch pipe 34 is closed before the second cooling step S2 (S40), and liquefied hydrogen gas is not discharged from the branch pipe 34 in the second cooling step S2. In the second cooling step S2, the valve 43 of the main line 33 is adjusted to open (S50). Note that the term "adjusted open" refers to a state in which the opening degree of the valve is adjusted in the range from fully closed to fully open as necessary. As a result, liquefied hydrogen is supplied to the main line 33 downstream of the valve 43, and the main line 33 is continuously cooled. At this time, since the main line 33 has already been cooled to below -220° C., even if the flow rate of liquefied hydrogen increases by adjusting the valve 43, the cooling speed will not become excessive.

After opening the valve 43, the temperature between the valves 42 and 43 is checked (S60). Although the specific form of temperature confirmation is not particularly limited, typically, the piping temperature of the main line 33 is confirmed. A thermometer 51 can be used to check the temperature. When the temperature between the valves 42 and 43 is equal to or higher than the temperature of liquefied hydrogen (NO in S60), the opening degree of the valve 43 is increased (S65) to increase the flow rate of liquefied hydrogen. If the temperature between the valves 42 and 43 is near the temperature of liquefied hydrogen (YES in S60), cooling is terminated (S70). The temperature of liquefied hydrogen is approximately -253°C (20K).

Next, a temperature confirmation method according to the present disclosure will be explained. Although the equipment that implements the temperature confirmation method according to the present disclosure is not particularly limited, it is suitably implemented, for example, in the cargo handling equipment 1 described above. A temperature confirmation method according to the present disclosure is a method of estimating the temperature of a main line having a vacuum insulation structure by confirming the temperature of a branch pipe. As described above, in the cargo handling equipment 1, the main line 33 has the vacuum insulation structure S, whereas at least a portion of the branch pipes 34 do not have the vacuum insulation structure S and are constructed from a single pipe. The temperature of this part can be measured by a more general temperature measurement method. By checking in advance the correlation between the temperature of the single pipe portion of the branch pipe 34 and the temperature of the main line 33 to be cooled, the temperature of the main line can be estimated from the branch pipe temperature.

The temperature in the branch pipe 34 may be measured using a thermometer, or may be measured by other methods. For example, when a single pipe of the branch pipe 34 is cooled to a temperature lower than the air liquefaction point, liquid air is generated at the pipe outlet or on the pipe surface. It is also preferable to check the temperature by visually observing the generation of liquefied air.

(Example)
FIG. 3 shows performance data when the cooling step in the cryogenic liquefied gas cargo handling method according to the present disclosure is performed in the transfer facility 30 schematically shown in FIG. 1. FIG. 3 shows a portion of the cooling process that corresponds to the first cooling step. In FIG. 3, changes over time in the valve opening degrees (%) of the valves 42 and 43 are shown. Additionally, the temperature (° C.) of thermometers 51a and 51b placed above and below the main line 33, respectively, changes over time. Furthermore, the time course of the temperature change rate (cooldown rate, °C/h) of the thermometers 51a and 51b is shown (right axis). The appropriate range for the cool-down rate was between -50°C/h and 50°C/h.

Referring to FIG. 3, opening and closing of valve 44 was repeated from 0 minutes to 300 minutes while maintaining the opening degree of valve 42 at 10%. The opening degree of the valve 42 was set to 100% at 300 minutes. The opening and closing of the valve 44 was repeated from 300 minutes to 900 minutes while maintaining the opening degree of the valve 42 at 100%. The valve 43 was kept fully closed from 0 minutes to 900 minutes.

The pipe temperature was about 10° C. at the start of cooling (0 minutes). 900 minutes after the start of cooling, it was cooled to -200°C or lower. The cooldown rate during this time was within the appropriate range. To explain in more detail, the cool-down rate of the temperature at the upper part of the pipe (thermometer 51a) was maintained within an appropriate range from 0 minutes to 900 minutes, with only slight deviations. The lowest cool-down rate was -59.4°C/h (103 minutes). The cool-down rate of the temperature at the bottom of the pipe (thermometer 51b) was mostly maintained within an appropriate range from 0 minutes to 300 minutes. When extracting liquefied hydrogen from a large-diameter pipe, it was difficult to control the cool-down rate at this stage, but a significant improvement was seen. Also, from 300 minutes to 900 minutes, the cooldown rate remained within a reasonable range with only minor deviations. The lowest cool-down rate was -109.8°C/h (at 204 minutes).

The vertical difference in pipe temperature is the difference between the temperature at the upper part of the pipe (thermometer 51a) and the temperature at the lower part of the pipe (thermometer 51b). From 0 minutes to 900 minutes, the vertical difference in pipe temperature was suppressed to within 70°C and maintained within the control value. At 900 minutes, valve 43 was opened 100%. The main line was further cooled by opening the valve 43 and allowing liquefied hydrogen to flow through the main line.

The embodiments disclosed herein are illustrative in all respects, and should be understood not to be restrictive. The scope of the present invention is indicated by the claims rather than the above description, and it is intended that all changes within the meaning and range equivalent to the claims are included.

1 cargo handling equipment, 10 tank, 20 ship, 30 transfer equipment, 31 first piping, 32 second piping, 33 main line, 34 branch pipe, 41, 42, 43, 44 valve, 51 thermometer, 71 tray.

Claims (10)

In a cargo handling method for cryogenic liquefied gas, the cryogenic liquefied gas is transferred from a tank containing the cryogenic liquefied gas via a transfer facility,
including a cooling step of cooling a main line included in the transfer equipment,
The cooling step includes:
A first step of extracting a liquid cryogenic liquefied gas from the tank and distributing it to the main line;
After the first step, a second step of extracting a liquid cryogenic liquefied gas from the tank and circulating it through the main line to further cool the main line,
The cryogenic liquefied gas, which is the liquid distributed in the first step, branches from the main line and is discharged as a gas from a branch pipe having a diameter of 1/4 or less of the main line,
The cryogenic liquefied gas, which is the liquid distributed in the second step, is not discharged from the branch pipe, but is distributed downstream from the branching point between the main line and the branch pipe.
How to handle cryogenic liquefied gas. In the first step, opening and closing of a valve provided in the branch pipe is repeated,
Cryogenic liquefied gas is drawn into the main line from the tank according to the amount of the gas discharged from the branch pipe.
The method for handling cryogenic liquefied gas according to claim 1. At the same time as the first step or after the first step, a temperature confirmation step is included,
The second step is started when it is confirmed in the temperature confirmation step that the temperature of the main line is below a predetermined temperature.
The method for handling cryogenic liquefied gas according to claim 1 or 2. The cryogenic liquefied gas is liquefied hydrogen, and the predetermined temperature is below the liquefaction point temperature of air.
The method for handling cryogenic liquefied gas according to claim 3. The temperature checking step is performed by checking the temperature of the branch pipe,
The method for handling cryogenic liquefied gas according to claim 3. The temperature confirmation step includes:
This is done by checking the temperature of the part of the branch pipe that does not have a vacuum insulation structure.
The method for handling cryogenic liquefied gas according to claim 5. a tank containing cryogenic liquefied gas;
a first pipe having a first end connected to the tank;
a second pipe having a second end connected to the tank below the first pipe in the vertical direction;
A third pipe connected to a third end of the first pipe that is an end opposite to the first end and a fourth end of the second pipe that is an end opposite to the second end. and,
a fourth pipe that branches from the middle of the third pipe and has a smaller diameter than the third pipe;
Equipped with
A first opening/closing mechanism is provided between the first end and the third end of the first pipe, and the first opening/closing mechanism is capable of switching between a communicating state and a closed state of the first pipe,
A second opening/closing mechanism is provided between the second end and the fourth end of the second pipe, and is capable of switching the second pipe between a communicating state and a closed state.
A third opening/closing mechanism capable of switching the third piping between a communicating state and a closed state is provided downstream of the connecting portion with the first piping and the connecting portion with the second piping in the third piping. is,
The fourth pipe is provided with a fourth opening/closing mechanism that can switch between a communicating state and a closed state of the fourth pipe,
The fourth pipe branches from the third pipe upstream of the third opening/closing mechanism in the third pipe,
The first piping, the second piping, and the third piping are composed of vacuum insulated double pipes,
At least a portion of the fourth piping does not have a vacuum insulation structure.
Cargo handling equipment for cryogenic liquefied gas. the cryogenic liquefied gas is liquefied hydrogen or liquefied helium;
The cargo handling equipment for cryogenic liquefied gas according to claim 7. The diameter of the fourth pipe is 1/4 or less of the diameter of the third pipe ,
The cargo handling equipment for cryogenic liquefied gas according to claim 7. In the cargo handling equipment for cryogenic liquefied gas according to any one of claims 7 to 9,
measuring the piping temperature in a portion of the fourth piping that does not have a vacuum insulation structure;
or confirming the temperature by visually checking the portion of the fourth pipe that does not have a vacuum insulation structure;
Temperature confirmation method in cryogenic liquefied gas cargo handling equipment.

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