KR20240002494A - Liquid hydrogen storage tank for zero boil off - Google Patents

Abstract

The liquid hydrogen storage tank for ZBO according to an embodiment of the present invention includes a vacuum tank with a vacuum inside, a storage tank disposed inside the vacuum tank and storing liquid hydrogen, and a storage tank to surround the outside of the storage tank. and a radiation shield disposed between the vacuum tank and blocking radiant heat intrusion transmitted to the storage tank, installed on top of the radiation shield and the storage tank and maintaining the radiation shield and the storage tank at a preset cryogenic temperature, respectively. It includes a cryogenic refrigerator for cooling, and a temperature gradient eliminator provided in a structure capable of heat transfer on the outer surface of the radiation shield and removing a temperature gradient generated between the upper and lower portions of the radiation shield.

Description

Liquid hydrogen storage tank for ZBO {LIQUID HYDROGEN STORAGE TANK FOR ZERO BOIL OFF}

The present invention relates to a liquid hydrogen storage tank for ZBO, and more specifically, to prevent radiant heat intrusion through the radiation shield by eliminating the temperature gradient of the radiation shield used in the liquid hydrogen storage tank that stores liquid hydrogen by cooling it to cryogenic temperatures. This is about a liquid hydrogen storage tank for ZBO that can effectively prevent it.

Recently, due to the increasing demand for hydrogen, which has been in the spotlight as an eco-friendly energy source, there is a need to develop liquid hydrogen-based infrastructure to store, transport, and utilize hydrogen in large quantities.

Generally, hydrogen is stored in a liquid state in tanks, or is transported or utilized in that state. When liquid hydrogen is stored in a tank as described above, heat loss is inevitable due to the temperature difference between the liquid hydrogen and the external atmosphere. Therefore, insulated storage tanks are used to reduce heat loss and evaporation of liquefied hydrogen due to temperature rise.

Existing insulated storage tanks maintain the internal pressure appropriately by discharging the gas when the internal pressure increases while storing cryogenic gas. However, since hydrogen gas is a flammable gas, discharging it into the atmosphere is very dangerous and causes increased economic damage. For this reason, existing insulated storage tanks not only require the installation of safety devices for discharging gas, but also have very severe restrictions on the discharge location.

To solve this problem, a liquid hydrogen storage tank for ZBO (zero boil off) equipped with a refrigerator has recently been developed and is widely used. In other words, the liquid hydrogen storage tank for ZBO liquefies evaporated hydrogen gas using a refrigerator, so that internal pressure can be properly maintained and hydrogen gas is not discharged, ensuring both safety and economic efficiency.

In particular, the liquid hydrogen storage tank for ZBO uses a radiation shield to prevent radiant heat intrusion. The radiation shield is a structure in which cooling is achieved by installing a refrigerator at the top, but as the capacity of the storage tank increases, the radiation shield also increases, so there is a high possibility that the temperature gradient of the radiation shield will increase significantly due to external heat intrusion.

As described above, if the temperature gradient of the radiation shield installed in the liquid hydrogen storage tank for ZBO increases, the radiation shielding performance of the radiation shield decreases, resulting in an increase in the pressure and temperature of hydrogen and an increase in the amount of power for operating the refrigerator. cause. To solve this problem, there is a method of increasing the thickness of the radiation shielding shield, but this has the problem of increasing the unit cost and weight of the radiation shielding shield.

Therefore, there is an urgent need to develop a technology that can eliminate the temperature gradient of the radiation shield without increasing the thickness of the radiation shield for liquid hydrogen storage tanks for ZBO. For reference, related prior art documents include Korea Patent Publication No. 10-2013-0123637 (title of the invention: storage tank including radiant heat shielding device for suppressing evaporative gas of ＮＮＧ carrier ships, publication date: 2013.11.04) .

Korean Patent Publication No. 10-2013-0123637 (published on November 4, 2013)

An embodiment of the present invention is a liquid hydrogen for ZBO that can simply and effectively remove the temperature gradient of the radiation shield without increasing the thickness of the radiation shield in the liquid hydrogen storage tank for ZBO that stores liquid hydrogen by cooling it to a cryogenic temperature. Provides a hydrogen storage tank.

In addition, an embodiment of the present invention is a liquid hydrogen storage tank for ZBO that can stably prevent radiant heat intrusion through the radiation shield and local temperature rise of the radiation shield by ensuring performance improvement and performance uniformity of the radiation shield. provides.

According to one embodiment of the present invention, a vacuum tank with a vacuum inside, a storage tank disposed inside the vacuum tank and storing liquid hydrogen, and disposed between the storage tank and the vacuum tank to surround the outside of the storage tank. a radiation shield that blocks radiant heat intrusion transmitted to the storage tank, a cryogenic freezer installed on the radiation shield and an upper part of the storage tank and cooling the radiation shield and the storage tank to a preset cryogenic temperature, respectively, and A liquid hydrogen storage tank for ZBO is provided, which is provided with a structure capable of heat transfer on the outer surface of the radiation shield and includes a temperature gradient eliminator that removes the temperature gradient generated between the upper and lower portions of the radiation shield.

Preferably, the temperature gradient eliminator may be provided as a heat pipe attached long along the direction of gravity to the outer surface of the radiation shield.

Preferably, the liquid hydrogen storage tank for ZBO according to an embodiment of the present invention includes a first support provided between the vacuum tank and the lower part of the radiation shielding shield and supporting the radiation shielding shield, and the radiation shielding shield. It may further include a second support provided between the lower portion of the storage tank and supporting the storage tank.

The radiation shield may be formed in a tank shape corresponding to the storage tank, and a temperature gradient may be generated in an upward and downward direction by radiant heat transmitted to the lower part of the radiation shield through the first support.

The heat pipe may be operated to transfer heat in a vertical direction of the radiation shield.

Preferably, a plurality of heat pipes may be arranged side by side on the outer surface of the radiation shield and spaced apart from each other along the perimeter of the radiation shield.

Preferably, the heat pipe includes a pipe member formed of a material capable of heat transfer and extending long along the direction of gravity, and accommodated in a closed space formed inside the pipe member, and liquid or liquid depending on the temperature transmitted through the pipe member. It may include a working fluid that changes phase into a gas.

Here, a condensation portion positioned to enable heat transfer to the upper part of the radiation shield cooled by the cryogenic refrigerator may be formed at the top of the heat pipe, and the heat intrusion through the first support may be formed at the bottom of the heat pipe. An evaporation portion positioned to enable heat transfer may be formed at the bottom of the radiation shield.

At this time, the working fluid may be operated in a condensation mode in which it is condensed into a liquid in the condensation unit and flows downward by gravity, and in an evaporation mode in which it is evaporated into a gas in the evaporation unit and rises upward.

Additionally, the pipe member may be made of copper material to have high heat exchange performance with the radiation shield. The working fluid may be provided as nitrogen gas that changes phase into liquid or gas depending on the temperature of the radiation shield transmitted through the pipe member.

Preferably, the cryogenic refrigerator includes a first cooling unit provided on an upper portion of the radiation shielding shield and cooling the radiation shielding shield to a first cooling temperature, and a liquid hydrogen provided on an upper portion of the storage tank and stored in the storage tank. It may include a second cooling unit that cools the storage tank to a second cooling temperature lower than the first cooling temperature to maintain the storage tank in a liquefied state.

Preferably, the liquid hydrogen storage tank for ZBO according to an embodiment of the present invention is disposed between the vacuum tank and the radiation shield to surround the outside of the radiation shield and the temperature gradient eliminator, and is disposed between the radiation shield and the radiation shield. It may further include an insulating member that insulates the temperature gradient eliminator.

The liquid hydrogen storage tank for ZBO according to an embodiment of the present invention improves the performance and performance of the radiation shield by easily removing the temperature gradient of the radiation shield by simply changing the structure without increasing the thickness and weight of the radiation shield. By ensuring uniformity, it is possible to effectively prevent radiant heat intrusion through the radiation shield and local temperature rise due to the temperature gradient of the radiation shield.

In addition, the liquid hydrogen storage tank for ZBO according to an embodiment of the present invention reduces the temperature gradient of the radiation shield by simply changing the structure by providing a temperature gradient eliminator provided as a heat pipe along the direction of gravity on the outer surface of the radiation shield. Because it is effectively removed, there is no need to significantly change the design and manufacturing process of the liquid hydrogen storage tank for ZBO, and it can be easily applied to existing liquid hydrogen storage tanks for ZBO.

In addition, the liquid hydrogen storage tank for ZBO according to an embodiment of the present invention uses a heat pipe to increase heat transfer performance between the upper part of the radiation shield where the cryogenic refrigerator is installed and the lower part of the radiation shield where the first and second supports are provided. Because of this structure, it is possible to eliminate the temperature gradient of the radiation shield even if the thickness and weight of the radiation shield are further reduced, thus reducing the manufacturing cost of the radiation shield and the first and second supports without reducing the performance of the radiation shield. can be reduced.

In addition, the liquid hydrogen storage tank for ZBO according to an embodiment of the present invention can prevent local heat intrusion into the storage tank by eliminating the temperature gradient of the radiation shield using a heat pipe, and the liquid stored in the storage tank Due to the increase in hydrogen temperature, it is possible to prevent the internal pressure of the storage tank from increasing or the power amount of the cryogenic refrigerator to increase.

Figure 1 is a diagram schematically showing the internal structure of a liquid hydrogen storage tank for ZBO according to an embodiment of the present invention.
FIG. 2 is a perspective view showing the radiation shield and heat pipes shown in FIG. 1.
FIG. 3 is a diagram schematically showing the internal structure of the heat pipe shown in FIG. 2.
FIG. 4 is a diagram showing the results of a modeling experiment of a radiation shield for the liquid hydrogen storage tank for ZBO shown in FIG. 1 and the conventional liquid hydrogen storage tank for ZBO.

Hereinafter, embodiments according to the present invention will be described in detail with reference to the attached drawings. However, the present invention is not limited or limited by the examples. The same reference numerals in each drawing indicate the same members.

Figure 1 is a diagram schematically showing the internal structure of the liquid hydrogen storage tank 100 for ZBO according to an embodiment of the present invention, and Figure 2 is a diagram showing the radiation shield 130 and the heat pipe 150 shown in Figure 1. ) and FIG. 3 is a diagram schematically showing the internal structure of the heat pipe 150 shown in FIG. 2. FIG. 4 is a diagram showing the results of a modeling experiment of a radiation shield for the liquid hydrogen storage tank 100 for ZBO shown in FIG. 1 and the conventional liquid hydrogen storage tank 100 for ZBO.

Referring to FIG. 1, the liquid hydrogen storage tank 100 for ZBO according to an embodiment of the present invention includes a vacuum tank 110, a storage tank 120, a radiation shield 130, a cryogenic refrigerator 140, It may include a temperature gradient eliminator, a first supporter 160, and a second supporter 170.

In the liquid hydrogen storage tank 100 for ZBO of this embodiment, the vacuum tank 110, the storage tank 120, and the radiation shield 130 are provided in a cylindrical tank structure erected elongated in the vertical direction, but are not limited to this. It can be manufactured as a cylindrical tank structure that lies long in the horizontal direction, or it can also be manufactured as a tank structure of a shape other than cylindrical.

In addition, in the liquid hydrogen storage tank 100 for ZBO of this embodiment, the cryogenic refrigerator 140 may be installed on the upper part of the storage tank 120 and the radiation shield 130, respectively, and the first support 160 It may be placed below the vacuum tank 110 and the radiation shield 130, and the second support 170 may be placed below the radiation shield 130 and the storage tank 120. Therefore, in this embodiment, heat intrusion from the outside may occur into the lower part of the radiation shield 130 through the first support 160, but the cryogenic freezer 140 cools the upper part of the radiation shield 130 and Therefore, the temperature gradient of the radiation shield 130 may occur in a direction where the temperature increases from the top to the bottom.

In addition, in this embodiment, the height direction of the liquid hydrogen storage tank 100 for ZBO is set to the vertical direction, but the lower direction of the liquid hydrogen storage tank 100 for ZBO is set to correspond to the gravity direction (G). .

Referring to FIG. 1, the vacuum tank 110 of this embodiment is a tank that maintains its interior in a vacuum state, and a vacuum pump may be provided on one side. Inside the vacuum tank 110 as described above, a storage tank 120, a radiation shield 130, a cryogenic freezer 140, a temperature gradient eliminator, and the first and second supports 160 and 170 can be accommodated. . Therefore, the vacuum tank 110 not only serves to protect the storage tank 120, the radiation shield 130, and the cryogenic freezer 140 from external shock or vibration, but also protects the storage tank 120 from abnormalities. It can also serve as a shield against hydrogen gas leaking out.

Referring to FIG. 1, the storage tank 120 of this embodiment is a tank that stores liquid hydrogen (H), and may be placed inside the vacuum tank 110. A vacuum insulating space may be formed between the storage tank 120 and the vacuum tank 110 in a shape that surrounds the outside of the storage tank 120. For reference, the storage tank 120 may be designed with sufficient strength to safely respond to the increase in gas pressure generated when liquid hydrogen (H) evaporates, and various safety devices may be installed.

Referring to FIG. 1, the radiation shield 130 of this embodiment is a shield member that blocks radiant heat intrusion transmitted to the storage tank 120. The radiation shield 130 as described above is disposed between the storage tank 120 and the vacuum tank 110, and may be formed to surround the outside of the storage tank 120. For example, the radiation shield 130 may be formed larger than the storage tank 120 in a tank shape corresponding to the storage tank 120, and the storage tank 120 is accommodated inside the radiation shield 130. It can be placed in a structure.

The lower part of the radiation shielding shield 130 can be stably fixed at a position spaced upward from the lower part of the vacuum tank 110 by the first support 160 so as not to contact the inner surface of the vacuum tank 110, The upper part of the radiation shielding shield 130 may be connected to the first cooling unit 142 of the cryogenic refrigerator 140, which will be described later, to be cooled by the cryogenic refrigerator 140.

Therefore, due to the radiant heat intrusion delivered to the lower part of the radiation shield 130 through the first support 160 and the cold air delivered to the upper part of the radiation shield 130 by the cryogenic freezer 140, the radiation shield ( The temperature gradient of 130) can occur in a pattern where the temperature increases downward along the direction of gravity.

Referring to FIG. 1, the cryogenic refrigerator 140 of this embodiment is a cooling member that cools the radiation shield 130 and the storage tank 120 to a preset cryogenic temperature, respectively, and includes the radiation shield 130 and the storage tank ( 120) can be installed at the top. Hereinafter, in this embodiment, the cryogenic freezer 140 is installed independently on the upper part of the radiation shield 130 and the storage tank 120, so that the radiation shield 130 and the upper part of the storage tank 120 are stored at different temperatures. Although it is described as cooling, it is not limited to this, and a structure in which the radiation shield 130 and the upper part of the storage tank 120 are simultaneously cooled using a single cryogenic refrigerator 140 is also possible.

For example, the cryogenic freezer 140 of this embodiment may include a first cooling unit 142 and a second cooling unit 144.

The first cooling unit 142 may cool the upper part of the radiation shield 130 to the first cooling temperature. The first cooling unit 142 may be connected to the upper part of the radiation shield 130 in a structure capable of transferring heat. The first cooling unit 142 as described above may be operated with the goal of cooling the temperature of the radiation shield 130 to the first cooling temperature to block radiant heat intrusion into the storage tank 120. For example, in this embodiment, the first cooling temperature can be set to an absolute temperature range of 77 K (kelvin) to 100 K.

The second cooling unit 144 may cool the storage tank 120 to a second cooling temperature lower than the first cooling temperature to maintain the liquid hydrogen (H) stored in the storage tank 120 in a liquid state. The second cooling unit 144 may be provided to penetrate the upper part of the storage tank 120. The second cooling unit 144 as described above may be operated with the goal of cooling the temperature of the storage tank 120 to the second cooling temperature to convert and maintain hydrogen gas into liquid hydrogen (H). For example, in this embodiment, the second cooling temperature can be set to an absolute temperature range of 20 K.

Here, a cooling fin member 148 may be installed at the end of the second cooling unit 144 to better transmit the cold air of the second cooling unit 144 to the inside of the storage tank 120. The cooling fin member 148 is preferably disposed at the inner center of the upper part of the storage tank 120. The cooling fin member 148 as described above is composed of a plurality of cooling fins, and may be made of a material with a high heat transfer coefficient to increase heat transfer efficiency.

Additionally, a cooler support portion 146 may be provided on the cooling fin member 148 and the storage tank 120 to stably support the cooling fin member 148. A plurality of cooler supports 146 as described above may be used to stably support the cooling fin member 148. The lower end of the cooler support part 146 may be connected to the cooling fin member 148, and the upper end of the cooler support part 146 may be connected to the upper part of the storage tank 120.

Meanwhile, in this embodiment, the first cooling unit 142 and the second cooling unit 144 are described as independently receiving cold air from a single refrigerator body, but the first cooling unit 142 and the second cooling unit ( 144), a method of installing each refrigerator body and operating them individually is also applicable.

Referring to Figures 1 to 3, the temperature gradient remover of this embodiment is a member that removes the temperature gradient generated between the upper and lower parts of the radiation shield 130, and transfers heat to the outer surface of the radiation shield 130. It can be prepared in any possible structure.

For example, the temperature gradient eliminator of this embodiment may be provided as a heat pipe 150 attached long along the direction of gravity to the outer surface of the radiation shield 130. The heat pipe 150 as described above may be operated to transfer heat in the vertical direction of the radiation shield 130.

Here, a plurality of heat pipes 150 may be arranged side by side on the outer surface of the radiation shield 130. At this time, the plurality of heat pipes 150 may be arranged along the circumference of the radiation shield 130 to be spaced apart from each other at equal intervals.

As shown in FIG. 3 , the heat pipe 150 may include a pipe member 152 and a working fluid 154 .

The pipe member 152 may be made of a metal material with excellent heat transfer performance, and may be manufactured in the shape of a pipe extending long along the direction of gravity. By shielding both ends of the pipe member 152 as described above, a closed space extending in the direction of gravity can be formed inside the pipe member 152. For example, in this embodiment, the pipe member 152 may be made of copper material that has high heat exchange performance with the radiation shield 130.

The working fluid 154 may be accommodated in a closed space formed inside the pipe member 152, and may be phase changed into either liquid or gas depending on the temperature transmitted through the pipe member 152. For example, in this embodiment, the working fluid 154 may be provided as nitrogen gas (N1, N2) that changes phase into liquid or gas depending on the temperature of the radiation shield 130 transmitted through the pipe member 152. there is. That is, the nitrogen gas (N1, N2) is evaporated into nitrogen gas (N1) by the heat transmitted from the bottom of the radiation shield 130, and is converted into liquid nitrogen by the cold air transmitted from the top of the radiation shield 130. It has a phase change temperature for condensation to (N2).

As shown in FIG. 3, the heat pipe 150 moves to the operating areas of the condensation section (C), the passage section (P), and the evaporation section (V) along the direction of gravity based on the operating mode of the working fluid 154. can be distinguished.

Describing the operating mode of the working fluid 154, the working fluid 154 can repeatedly operate in condensation mode, flow mode, and evaporation mode according to the temperature gradient of the radiation shield 130 within the pipe member 152. there is.

Here, in the condensation mode, the gaseous working fluid 154 may be condensed into a liquid by the extremely low temperature transmitted from the upper part of the radiation shield 130 and then flow downward by gravity. And, in the flow mode, the working fluid 154 in a liquid state condensed in the condensation mode may flow downward along the surface of the pipe member 152 by gravity. In addition, in the evaporation mode, the liquid working fluid 154 flowing in the flow mode is evaporated into gas by the relatively high temperature transmitted from the lower part of the radiation shield 130 and then raised upward by buoyancy. .

When explaining the condensation portion (C), passage portion (P), and evaporation portion (V) of the heat pipe 150, the condensation portion (C), passage portion (P), and evaporation portion (V) are the heat pipe 150. It has a structure continuously connected along the longitudinal direction of the heat pipe 150, and may be arranged sequentially from the top to the bottom of the heat pipe 150.

Here, the condensation unit (C) may be provided on the upper part of the heat pipe 150 to be installed on the upper part of the radiation shielding shield 130, which is cooled by the first cooling unit 142 of the cryogenic freezer 140, and the passage. The portion (P) may be provided in the middle of the heat pipe 150 to be installed in the middle of the radiation shield 130 between the upper and lower portions of the radiation shield 130, and the evaporation portion (V) may be provided in the middle of the heat pipe 150. It may be provided below the heat pipe 150 to be installed below the radiation shield 130 through which heat penetrates through the first support 160.

Meanwhile, in the heat pipe 150 of this embodiment, the condensation portion (C) and the evaporation portion (V) are formed to have a larger area than the passage portion (P) in order to increase the phase change efficiency of the working fluid 154. It is also possible to form a spiral shape with a predetermined slope with respect to the direction of gravity on the outer surface of the radiation shield 130. In order to increase heat transfer performance with the radiation shield 130, the radiation shield 130 It is also possible to add a sheet of high heat transfer material between the and.

Referring to FIG. 1, the first support 160 of this embodiment is a member that supports the lower part of the radiation shield 130, and is provided between the lower part of the vacuum tank 110 and the lower part of the radiation shield 130. It can be. The first support 160 as described above can support the radiation shield 130 at a predetermined distance from the inner surface of the vacuum tank 110. However, the first support 160 may serve as a passage for abnormally transferring heat from the vacuum tank 110 to the radiation shield 130 due to the temperature difference between the vacuum tank 110 and the radiation shield 130. there is.

Referring to FIG. 1, the second support 170 of this embodiment is a member that supports the lower part of the storage tank 120 and is provided between the lower part of the radiation shielding shield 130 and the lower part of the storage tank 120. You can. The second support 170 as described above can support the storage tank 120 at a predetermined distance from the inner surface of the radiation shield 130. However, the second support 170 may serve as a passage for abnormally transferring the heat of the radiation shield 130 to the storage tank 120 due to the temperature difference between the storage tank 120 and the radiation shield 130. there is.

Therefore, in this embodiment, by eliminating the temperature gradient of the radiation shield 130 using the heat pipe 150, heat intrusion through the first support 160 and the second support 170 can be prevented in advance. there is.

As shown in FIG. 1, the liquid hydrogen storage tank 100 for ZBO according to an embodiment of the present embodiment further includes a radiation shield 130 and an insulating member 180 that insulates the temperature gradient eliminator from the outside. can do. The insulation member 180 may be provided in various shapes and locations, but in this embodiment, the insulation member 180 has a cylindrical shape surrounding the outside of the radiation shield 130 and the temperature gradient eliminator and is attached to the vacuum tank 110. It can be placed between and the radiation shielding shield 130.

Meanwhile, Figure 4 shows the results of a modeling experiment for the liquid hydrogen storage tank 100 for ZBO of this embodiment and the existing liquid hydrogen storage tank 10 for ZBO.

That is, Figure 4 (a) shows the temperature gradient of the radiation shield 13 used in the existing liquid hydrogen storage tank 10 for ZBO. The plurality of heat pipes 150 are not installed in the radiation shield 130 as described above. As shown in (a) of FIG. 4, it is confirmed that a temperature gradient is formed in which the temperature increases toward the lower part of the radiation shield 130. Therefore, there is a high possibility that the liquid hydrogen (H) in the storage tank 120 adjacent to the lower part of the radiation shield 13 will evaporate into hydrogen gas due to the temperature gradient of the radiation shield 13, and accordingly, the storage tank 120 ) can significantly increase the risk of the internal pressure of the gas rising rapidly or hydrogen gas leaking to the outside from the storage tank 120.

On the other hand, Figure 4 (b) shows the temperature gradient of the radiation shield 130 used in the liquid hydrogen storage tank 100 for ZBO of this embodiment. A plurality of heat pipes 150 are installed in the radiation shield 130 as described above. As shown in (b) of FIG. 4, it is confirmed that the entire temperature of the radiation shield 130 appears uniform and there is almost no temperature gradient. Therefore, since the radiation shield 130 is sufficiently cooled by the first cooling unit 142 of the cryogenic freezer 140, radiation heat intrusion into the storage tank 120 can be prevented in advance. At this time, the heat entering through the first support 160 may be absorbed by the heat pipes 150 and then transferred to the upper part of the radiation shield 130 and cooled by the first cooling unit 142.

As described above, the embodiments of the present invention have been described with specific details such as specific components and limited examples and drawings, but this is only provided to facilitate a more general understanding of the present invention, and the present invention is limited to the above embodiments. This does not mean that various modifications and variations can be made from this description by those skilled in the art. Accordingly, the spirit of the present invention should not be limited to the described embodiments, and all claims that are equivalent or equivalent to the claims as well as the following claims fall within the scope of the present invention.

100: Liquid hydrogen storage tank for ZBO
110: Vacuum tank
120: storage tank
130: Radiation shield
140: Cryogenic freezer
150: heat pipe
160: first support
170: second support
180: insulation member
G: direction of gravity
H: liquid hydrogen
N1: nitrogen gas
N2: Liquid nitrogen
C: condensation section
P: Passage part
V: Evaporation unit

Claims (9)

A vacuum tank with a vacuum inside;
a storage tank disposed inside the vacuum tank and storing liquid hydrogen;
a radiation shield disposed between the storage tank and the vacuum tank to surround the outside of the storage tank, and blocking radiation heat intrusion transmitted to the storage tank;
A cryogenic freezer installed on top of the radiation shield and the storage tank and cooling the radiation shield and the storage tank to a preset cryogenic temperature, respectively; and
a temperature gradient eliminator provided on the outer surface of the radiation shield in a structure capable of transferring heat, and removing a temperature gradient generated between the upper and lower portions of the radiation shield;
Liquid hydrogen storage tank for ZBO containing.
According to paragraph 1,
A liquid hydrogen storage tank for ZBO, wherein the temperature gradient eliminator is provided as a heat pipe attached long along the direction of gravity to the outer surface of the radiation shield.
According to paragraph 2,
a first support provided between the vacuum tank and a lower portion of the radiation shield and supporting the radiation shield; and
It further includes a second support provided between the radiation shield and the lower part of the storage tank and supporting the storage tank,
The radiation shield is formed in a tank shape corresponding to the storage tank, and a temperature gradient is generated in the vertical direction by radiant heat intrusion transmitted to the lower part of the radiation shield through the first support,
The heat pipe is a liquid hydrogen storage tank for ZBO, characterized in that it operates to transfer heat in the vertical direction of the radiation shield.
According to paragraph 3,
A liquid hydrogen storage tank for ZBO, wherein a plurality of heat pipes are arranged side by side on the outer surface of the radiation shield and spaced apart from each other along the circumference of the radiation shield.
According to paragraph 3,
The heat pipe is,
A pipe member formed of a material capable of heat transfer and extending long along the direction of gravity; and
a working fluid accommodated in a sealed space formed inside the pipe member and changing phase into a liquid or gas depending on the temperature transmitted through the pipe member;
Liquid hydrogen storage tank for ZBO containing.
According to clause 5,
A condensation portion is formed at the upper part of the heat pipe to enable heat transfer to the upper part of the radiation shield cooled by the cryogenic refrigerator, and a condensation portion is formed at the lower part of the heat pipe to allow heat to penetrate through the first support. An evaporation part is formed at the bottom to enable heat transfer,
The working fluid is operated in a condensation mode in which it is condensed into a liquid in the condensation unit and flows downward by gravity, and in an evaporation mode in which it is evaporated into a gas in the evaporation unit and rises upward. .
According to clause 5,
The pipe member is made of copper material to ensure high heat exchange performance with the radiation shield,
A liquid hydrogen storage tank for ZBO, wherein the working fluid is provided as nitrogen gas that changes phase into liquid or gas depending on the temperature of the radiation shield transmitted through the pipe member.
According to any one of claims 1 to 7,
The cryogenic freezer,
a first cooling unit provided on an upper portion of the radiation shielding shield and cooling the radiation shielding shield to a first cooling temperature; and
a second cooling unit provided on an upper portion of the storage tank and cooling the storage tank to a second cooling temperature lower than the first cooling temperature to maintain the liquid hydrogen stored in the storage tank in a liquefied state;
Liquid hydrogen storage tank for ZBO containing.
According to any one of claims 1 to 7,
an insulating member disposed between the vacuum tank and the radiation shield to surround the outside of the radiation shield and the temperature gradient eliminator, and insulating the radiation shield and the temperature gradient eliminator;
A liquid hydrogen storage tank for ZBO, further comprising:

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