KR20230171064A - Independent liquid hydrogen storage tank including a vacuum insulation layer and a method for implementing vacuum insulation thereof, marine transportation means including an independent liquid hydrogen storage tank - Google Patents

Abstract

An independent liquefied hydrogen storage tank including a vacuum insulation layer and a method of implementing vacuum insulation thereof are disclosed. An independent liquefied hydrogen storage tank including a vacuum insulation layer according to an aspect of the present invention includes a primary barrier that performs airtightness while directly contacting the liquefied hydrogen stored therein; A partition structure installed at a certain distance from the outside of the primary barrier and forming a closed space between the primary barrier and the primary barrier; and a vacuum insulation layer prepared by forming a closed space with a vacuum, wherein before the vacuum work on the vacuum insulation layer is performed, the closed space is replaced with a purge gas for the purpose of removing moisture and oxygen, and the vacuum work on the vacuum insulation layer is performed. Before or after this is performed, a cool-down process is performed in which a small amount of liquefied hydrogen is sprayed into the internal space of the primary barrier to pre-cool it, thereby reducing the temperature of the vacuum insulation layer and the temperature of the vacuum insulation layer due to a decrease in the temperature of the primary barrier. Due to the reduction in pressure of the vacuum insulation layer, the phase change of the residual substitution gas in the vacuum insulation layer due to the temperature drop in the vacuum insulation layer, and the reduction in pressure in the vacuum insulation layer due to the phase change of the substitution gas, an additional vacuum effect occurs on the vacuum insulation layer. It is characterized by:

Description

Independent liquid hydrogen storage tank including a vacuum insulation layer and a method for implementing vacuum insulation thereof, marine transportation including an independent liquid hydrogen storage tank {Independent liquid hydrogen storage tank including a vacuum insulation layer and a method for implementing vacuum insulation thereof, marine transportation means including an independent liquid hydrogen storage tank}

The present invention relates to an independent liquefied hydrogen storage tank including a vacuum insulation layer and a method of implementing vacuum insulation thereof. More specifically, the present invention relates to a high-performance insulation system including a vacuum insulation layer to enable transportation and storage of hydrogen with a significantly low boiling point. It is about a self-contained liquefied hydrogen storage tank and a method of effectively implementing its vacuum insulation.

In general, hydrogen transportation can be broadly divided into inland transportation and maritime transportation. Transportation of hydrogen inland can be accomplished using pipelines, dedicated transport vehicles, or railways, and transportation of hydrogen at sea can be accomplished through ships equipped with special storage facilities.

A common feature of hydrogen transportation via inland and sea, excluding pipelines, is that it is accomplished through transportation vehicles equipped with special storage facilities that can store hydrogen. In particular, for efficient transportation of hydrogen, it is a general opinion that it is desirable to store and transport gaseous hydrogen in a storage facility in a liquefied state by cooling and/or pressurizing it.

Various technologies can be applied to store liquefied hydrogen. Specifically, membrane type tank storage technology, which is applied both at sea and on land, and independent type tank storage technology, which is mainly applied at sea, can be considered. Independent tanks can be divided into Type C tanks, which are referred to as pressure vessels, and Type A tanks and Type B tanks, which are atmospheric tanks.

The above-mentioned storage technologies are currently commercialized and there is no great difficulty in technically implementing them, but these existing storage technologies are mainly designed to be suitable for the storage of LNG (liquefied natural gas) or LPG (liquefied petroleum gas). It is difficult to store and transport hydrogen, which has a significantly lower liquefaction temperature (boiling point) compared to LNG or LPG, without loss for a significant period of time using the insulation methods of these technologies.

In order to use existing storage technologies for storing liquefied hydrogen, design changes such as increasing the insulation thickness of the insulation system provided in the storage tank (or storage container) from several to several tens of times or additionally applying high-performance insulation such as vacuum insulation are required. This inevitably must be considered, and existing storage technologies cannot be directly applied to the storage of liquefied hydrogen, which has a significantly low boiling point.

Since gaseous hydrogen has a boiling point of -253℃ at atmospheric pressure, it must be cooled to that temperature to convert from gaseous state to liquid. Additionally, even in a pressurized environment, the temperature at which hydrogen liquefies is quite low. Even when pressurized to approximately 10 barg, hydrogen can be converted to liquid at -242°C.

Due to the phase change characteristics of hydrogen, a temperature difference of up to 300°C occurs between the external conditions of the storage tank, which is close to atmospheric temperature, and the inside of the storage tank, where liquefied hydrogen is stored at -253°C. This difference in temperature between the inside and outside of the storage tank becomes a factor in heat transfer, and heat immersion due to heat flux generated by heat transfer causes evaporation of the liquefied hydrogen stored inside the storage tank.

Evaporation of liquefied hydrogen occurring inside a storage tank ultimately results in loss of hydrogen during the hydrogen storage and transportation process. In the case of a pressurized storage tank, boil-off gas (BOG) can be stored inside the storage tank within the maximum design vapor pressure, but it is not possible to store boil-off gas (BOG) inside the storage tank at the critical point of hydrogen. It is required to manage it so that it does not prematurely, and if it is expected to exceed the allowable internal pressure due to continuous evaporation of liquefied hydrogen, the evaporation gas has no choice but to be released outside the storage tank.

In order to minimize transportation losses by reducing the evaporation rate of liquid hydrogen during maritime transportation of liquefied hydrogen, which has a significantly lower boiling point compared to LNG or LPG, measures are taken to increase the insulation performance of the storage tank where liquefied hydrogen is stored or to reduce heat loss. This must be provided.

The purpose of the present invention is to provide a liquefied hydrogen storage tank equipped with a high-performance insulation system and a maritime transportation means including the same so that liquid hydrogen can be stored and transported with minimal heat loss for a considerable period of time during maritime transportation of hydrogen. I'm doing it.

Among them, pressurized storage tanks can be operated relatively efficiently because they can control the pressure rise due to evaporation to a certain level of design pressure compared to normal pressure storage tanks. If heat loss can be minimized, cargo loss can be minimized. There is an advantage to being able to do it. Accordingly, the present invention seeks to design and construct a storage tank for storage/transportation of liquefied hydrogen and an insulation system built thereto in the form of a Type C independent tank classified by the International Maritime Organization (IMO).

The technical problems of the present invention are not limited to the technical problems mentioned above, and other technical problems not mentioned will be clearly understood by those skilled in the art from the description below.

According to one aspect of the present invention for achieving the above object, a primary barrier that performs airtightness while directly contacting the liquefied hydrogen stored therein; a partition structure installed at a certain distance from the outside of the primary barrier and forming a closed space between the primary barrier and the primary barrier; and a vacuum insulation layer prepared by forming the closed space in a vacuum, wherein before vacuum work on the vacuum insulation layer is performed, the closed space is replaced with a purge gas for the purpose of removing moisture and oxygen, and the vacuum insulation layer Before or after the vacuum operation is performed, a cool-down process of pre-cooling the internal space of the primary barrier by spraying a small amount of liquefied hydrogen is performed, thereby reducing the temperature of the vacuum insulation layer due to a decrease in the temperature of the primary barrier. and a decrease in the pressure of the vacuum insulation layer according to a decrease in the temperature of the vacuum insulation layer, and a phase change of the remaining substitution gas in the vacuum insulation layer according to a decrease in the temperature of the vacuum insulation layer and a decrease in the pressure of the vacuum insulation layer according to the phase change of the substitution gas. Due to the influence of, an independent liquefied hydrogen storage tank including a vacuum insulation layer can be provided, characterized in that an additional vacuum effect on the vacuum insulation layer occurs.

The substitution gas may be a material with a higher phase change temperature than hydrogen (H ₂ ).

The substitution gas undergoes a phase change from gas to liquid and/or solid at an absolute pressure of 3 bar or less and may be a material with a phase change temperature of -100°C or higher.

The substitution gas may be carbon dioxide (CO ₂ ).

An independent liquefied hydrogen storage tank according to one aspect of the present invention is a multi-layer insulation disposed to surround the outer surface of the primary barrier inside the vacuum insulation layer and filling the internal space of the vacuum insulation layer. It may further include at least one of the powder-type insulating materials.

The powder-type insulating material may be any one of perlite, hollow glass microspheres, and aerogel.

The auxiliary insulation layer may be composed of any one of a vacuum insulation panel, a foam-type organic insulation material including polyurethane foam, and an inorganic insulation material including glass wool.

An independent liquefied hydrogen storage tank according to one aspect of the present invention includes a plurality of first supports installed between the primary barrier and the partition structure to support them while maintaining a constant distance between the two structures; And it may further include a plurality of second supports supporting the partition structure.

In addition, the present invention can provide a maritime transportation means equipped with an independent liquefied hydrogen storage tank including at least one of the features described above.

The liquefied hydrogen storage tank may be an IMO Type C tank.

The maritime transport vehicle may be a liquefied hydrogen carrier.

Meanwhile, according to another aspect of the present invention for achieving the above object, a primary barrier that is in direct contact with the liquefied hydrogen stored inside and performs airtightness, and is installed at a certain distance from the outside of the primary barrier, In the independent liquefied hydrogen storage tank including a partition structure forming a closed space between the primary barrier and the closed space, a purification step of removing moisture and oxygen by injecting a purge gas into the closed space; A vacuum forming step of forming the closed space into a vacuum insulated space; And a loading preparation step of performing preliminary work including a cool-down process of pre-cooling the internal space of the primary barrier by spraying a small amount of liquefied hydrogen, wherein the loading preparation step is after the substitution step and the vacuum It is performed before or after the forming step, and the temperature of the vacuum insulated space decreases due to the temperature drop of the primary barrier that occurs in the loading preparation step, and the pressure of the vacuum insulated space decreases due to the temperature decrease in the vacuum insulated space, And due to the effect of the phase change of the remaining substitution gas in the vacuum insulation space as the temperature of the vacuum insulation space decreases and the pressure reduction in the vacuum insulation space due to the phase change of the substitution gas, an additional vacuum effect on the vacuum insulation space A method of implementing vacuum insulation of a stand-alone liquefied hydrogen storage tank including a vacuum insulation layer can be provided, which is characterized in that a occurs.

In the vacuum forming step, the space can be made into the vacuum insulation space by removing the air in the closed space using a vacuum pump.

The substitution gas may be a material with a higher phase change temperature than hydrogen (H ₂ ).

The substitution gas undergoes a phase change from gas to liquid and/or solid at an absolute pressure of 3 bar or less and may be a material with a phase change temperature of -100°C or higher.

The substitution gas may be carbon dioxide (CO ₂ ).

The present invention is optimized for the storage and transportation of liquefied hydrogen with a significantly low boiling point, and is equipped with a high-performance insulation system to store and transport liquefied hydrogen with minimal heat loss for a considerable period of time using vacuum insulation. Provides tanks and marine transportation including tanks.

The present invention can minimize the loss rate of liquefied hydrogen due to heat intrusion by securing excellent insulation performance through the implementation of vacuum insulation, and ultimately, the evaporation rate of liquefied hydrogen (BOG; Boil- It has the economic effect of significantly reducing the off rate and minimizing energy loss.

Furthermore, the present invention uses a substitution gas with a relatively high phase change temperature in the substitution process of the vacuum insulation space in addition to the configuration of the vacuum insulation space, thereby reducing the temperature change of the primary barrier and the phase of the substitution gas when creating a vacuum in the space. It is possible to implement a more effective vacuum environment by using additional pressure changes according to the change.

The effects of the present invention are not limited to the effects described above, and other effects not mentioned may be clearly understood from the description below.

Figure 1 is a diagram showing the structure of a liquefied hydrogen storage tank according to the present invention.
Figure 2 is a diagram showing the first support installed between the primary barrier and the partition structure of the liquefied hydrogen storage tank according to the present invention.
Figure 3 is a diagram showing a second support installed between the hull and the partition structure of the liquefied hydrogen storage tank according to the present invention.
Figure 4 is a flowchart showing a method of implementing vacuum insulation of a liquefied hydrogen storage tank according to an embodiment of the present invention.
Figure 5 is a flowchart showing a method of implementing vacuum insulation of a liquefied hydrogen storage tank according to another embodiment of the present invention.

In order to fully understand the present invention, its operational advantages, and the purposes and effects achieved by practicing the present invention, reference should be made to the accompanying drawings illustrating preferred embodiments of the present invention and the contents described in the accompanying drawings.

Matters expressed in the drawings attached to this specification may be somewhat different from the form actually implemented in schematic drawings to easily explain the embodiments of the present invention, and the sizes of each component shown in the drawings are for explanatory purposes. It can be exaggerated or reduced and does not mean the size that is actually applied.

The terminology used herein is merely used to describe specific embodiments and is not intended to limit the invention. For example, in this specification, “including” a certain component does not mean excluding other components, but may further include other components, unless specifically stated to the contrary.

In addition, it should be understood that saying that a component is 'connected' to another component includes direct connection as well as indirect connection, and that other components may exist between the two components. Singular expressions may be interpreted to include plural expressions unless the context clearly indicates otherwise.

In this specification, the terms 'top', 'top' or 'top', as customarily applied to storage tanks, refer to the direction toward the inside of the tank, regardless of the direction with respect to gravity, and likewise the terms 'lower', 'lower' or 'Down' refers to the direction toward the outside of the tank, regardless of the direction relative to gravity.

Hereinafter, the present invention will be described in detail by explaining preferred embodiments of the present invention with reference to the accompanying drawings. The embodiments described below are provided so that those skilled in the art can easily understand the technical idea of the present invention, and the present invention is not limited thereto.

Figure 1 is a diagram showing the structure of a liquefied hydrogen storage tank according to the present invention. Figure 2 is a diagram showing the first support installed between the primary barrier and the partition structure of the liquefied hydrogen storage tank according to the present invention, and Figure 3 is a diagram showing the first support installed between the partition structure and the hull of the liquefied hydrogen storage tank according to the present invention. This is a diagram showing the second support. Figures 2 and 3 are enlarged views of the portions marked 'A' and 'B' in Figure 1, respectively.

Referring to FIG. 1, the liquefied hydrogen storage tank 100 according to the present invention includes a primary barrier 110 that is in direct contact with the liquefied hydrogen stored therein and performs primary airtightness; A partition structure 120 that is installed at a certain distance from the outside of the primary barrier 110 and forms a closed space between the primary barrier 110 and the primary barrier 110; A vacuum insulation layer 130 prepared by vacuum forming a closed space formed between the primary barrier 110 and the partition structure 120; An auxiliary insulation layer 140 installed to surround the outside of the partition structure 120; A plurality of first supports 150 installed between the primary barrier 110 and the partition structure 120 to support the primary barrier 110; And it may include a plurality of second supports 160 installed between the partition structure 120 and the hull (H) to support the partition structure 120.

The liquefied hydrogen storage tank 100 according to the present invention can be mounted in a space (S) defined inside a transportation vehicle. Here, the means of transportation may preferably be a marine transportation means, that is, a ship, and the space (S) in which the liquefied hydrogen storage tank 100 is mounted may be a space partitioned by the hull (H).

The primary barrier 110 divides the space where liquefied hydrogen is stored in the liquefied hydrogen storage tank 100 according to the present invention, and performs primary airtightness while directly contacting the liquefied hydrogen.

The primary barrier 110 may have a metal airtight structure. The primary barrier 110 may be made of a metal material with strong low-temperature brittleness to safely store cryogenic liquefied hydrogen. For example, low-temperature steel that has been proven to be capable of storing liquefied hydrogen, including stainless steel, can be used. It can be applied.

Additionally, the primary barrier 110 may be provided as a pressure tank to allow internal pressure to rise to a certain level, and may have a cylindrical shape to easily withstand the pressure. Therefore, the overall shape of the liquefied hydrogen storage tank 100 according to the present invention, including the components surrounding the primary barrier 110, may also be provided in a cylindrical shape along the primary barrier 110.

The internal space of the primary barrier 110, that is, the space where liquefied hydrogen is stored, is equipped with piping for loading and unloading of liquefied hydrogen, a pump, a pump fixing structure, and various sensors, valves, equipment and equipment related to tank and cargo operation. It can be. Piping and equipment related to the loading and unloading of liquefied hydrogen can be connected to the outside through the primary barrier 110, and the penetration part of the primary barrier 110 must be kept airtight through welding, etc.

The penetration part from inside the primary barrier 110 corresponds to the part that penetrates the primary barrier 110 and connects to the outside for the operation of various sensors and equipment provided inside the primary barrier 110 and the transfer of cargo. And, it is characterized in that at least one penetrating portion is formed.

The partition structure 120 is a structure that is installed at a certain distance from the outside of the primary barrier 110 to form a closed space between the primary barrier 110 and maintains the structural integrity and insulation of the primary barrier 110. It can be responsible for maintaining the division of space at a constant level. The partition structure 120 may be configured to include the entire space of the primary barrier 110 from the outside.

The space between the primary barrier 110 and the partition structure 120 may largely be composed of a portion that functions as a vacuum insulation layer, a support structure for the primary barrier 110, and a penetration portion from inside the primary barrier 110. . In addition, the outer space of the partition structure 120 may be composed of a part that functions as an auxiliary insulation layer, a support structure for the partition structure 120, a penetration part to the outside of the partition structure 120, etc.

The closed space formed between the primary barrier 110 and the partition structure 120 creates a vacuum environment and becomes the vacuum insulation layer 130. The vacuum insulation layer 130 functions as a main insulation layer that primarily insulates the liquefied hydrogen stored inside the primary barrier 110.

The liquefied hydrogen storage tank 100 according to the present invention is filled in the internal space of the multi-layer thin-film insulation (MLI) 131 or vacuum insulation layer 130 installed to surround the outer surface of the primary barrier 110. Insulation performance can be improved by further including powder-type/bead-type insulation materials. Powder-type/bead-type insulation materials can be prepared from powder-type insulation materials that have excellent insulation performance in a vacuum environment, such as perlite, hollow glass microspheres, and aerogel.

More specifically, 10 to 100 layers of multilayer thin film insulation material 131 is wrapped around the outside of the primary barrier 110, or the powder-type insulation material described above is placed in the space between the primary barrier 110 and the partition structure 120. After filling, a vacuum forming operation for the corresponding space can be performed to form the vacuum insulation layer 130. At this time, the vacuum forming operation can be performed by operating a vacuum pump (VP) installed outside the storage tank 100 to suck air from the space between the primary barrier 110 and the partition structure 120. The vacuum line (VL) for sucking air may extend from the space between the primary barrier 110 and the partition structure 120 to the outside through the partition structure 120 and be connected to the vacuum pump VP. A pressure gauge (PT) may be installed on the vacuum line (VL) to check the degree of vacuum when forming a vacuum.

The liquefied hydrogen storage tank 100 according to the present invention adds a vacuum state to the space between the primary barrier 110 and the partition structure 120, and at the same time installs a multi-layer thin film insulation material 131 with excellent insulation performance within the space. Alternatively, it is possible to have an insulation structure in the form of “vacuum insulation + multi-layer thin film insulation” or “vacuum insulation + powder-type insulation” by filling it with powder or powder-type insulation. The multilayer thin film insulation material 131 and the powder-type insulation material may be selectively applied in addition to vacuum insulation, or both may be applied.

A first support 150 is installed in the space between the primary barrier 110 and the partition structure 120, that is, in the space of the vacuum insulation layer 130, to support and secure the space between the two structures 110 and 120. It can be.

Referring to FIG. 2, the first support 150 may be installed in the form of a key or support between the primary barrier 110 and the partition structure 120, and may be installed in the form of a key or support of the primary barrier 110. It can be responsible for maintaining structural integrity and the division of the insulation space composed of the vacuum insulation layer 130.

The first support 150 is made of a plastic material that can be used at extremely low temperatures, such as PCTFE (PolyChloroTriFluoroEthylene), PTFE (PolyTetraFluoroEthylene), and UHMWPE ( It may be composed of Ultra-High-Molecular-Weight PolyEthylene), etc.

The plurality of first supports 150 are fixed to or in contact with the support receiving portion 111 formed on the outside of the primary barrier 110 at each position, and are formed on the inside of the partition structure 120. It may be fixed to or in contact with the receiving portion 121.

In addition, the first support 150 includes being fixed to the support receiving portion 111 formed on the side of the primary barrier 110 and fixed to the support receiving portion 121 formed on the partition structure 120 side. It can be divided into two pieces, and the split pieces arranged up and down can be arranged to contact each other. For reference, here, ‘top and bottom’ refers to the ‘inside and outside’ of the storage tank, regardless of the direction of gravity.

The reason for dividing the first support body 150 into two parts is to configure the inner tank according to the heat shrinkage due to cryogenic temperature and/or the degree of freedom movement of the transportation vehicle (e.g., ship) on which the liquefied hydrogen storage tank 100 is mounted. This is so that when a relative displacement occurs between the car barrier 110 and the partition structure 120 constituting the outer tank, the first supports 150 divided into the upper and lower parts slide against each other to achieve structural stability (Figure 2).

On the other hand, if the above-described vacuum insulation layer 130 functions as the main insulation layer in the liquefied hydrogen storage tank 100 according to the present invention, the auxiliary insulation layer 140 adjusts the temperature of the vacuum insulation zone by the vacuum insulation layer 130 during vacuum operation. It is an auxiliary insulation layer whose insulation performance is determined (determination of insulation material and insulation thickness, etc.) to maintain the temperature below the required temperature.

Like the vacuum insulation layer 130, the auxiliary insulation layer 140 is vacuum-insulated by providing a separate compartment to enable the implementation of a vacuum environment, or is made of a vacuum insulation panel (VIP), polyurethane foam, and An insulating structure may be formed by attaching/installing any one of various insulating materials, including an organic insulating material in the same form of foam or an inorganic insulating material such as glass wool, to the outer surface of the partition structure 120. Of course, when the auxiliary insulation layer 140 is composed of a vacuum insulation layer, a multi-layer thin film insulation material can be installed or a powder-type insulation material can be filled in the internal space.

Meanwhile, a second support body 160 may be installed between the partition structure 120 and the inner wall of the hull (H) to support the two structures and secure space.

Referring to FIG. 3, the second support 160 may be installed in the form of a key or support between the partition structure 120 and the hull (H), similar to the first support 150, and may be installed in the form of a key or support of the partition structure 120. It functions to maintain structural integrity.

The second support 160 is constructed using wood or plastic materials that can be used at cryogenic temperatures, such as PCTFE, PTFE, UHMWPE, etc., to minimize loss due to heat transfer between the compartment structure 120 and the hull (H). It can be. The second support 160 may be sized to be greater than or equal to the effective thickness of the auxiliary insulation layer 140.

The plurality of second supports 160 are fixed to or in contact with the support receiving portion 122 formed on the outside of the partition structure 120 at each position, and the support receiving portion formed on the inner wall of the hull (H) ( It may be configured to be fixed to or in contact with HA).

In addition, the second support 160 is divided into two pieces and arranged so that the opposing surfaces of the split bodies arranged up and down are in contact with each other, and the partition structure 120 and the hull (H) constituting the outer tank of the storage tank 100 ) When a relative displacement occurs between the upper and lower parts, the second supports 160, which are divided into upper and lower parts, can achieve structural stability by sliding against each other (see FIG. 3), using the same principle as described for the first support 150. .

In Figure 1, the first support 150 and the second support 160 are shown as being disposed only on the upper and lower portions of the storage tank 100, but marine transportation on which the liquefied hydrogen storage tank 100 according to the present invention is mounted In consideration of the 6-degree-of-freedom movement of the means (e.g., a ship) or the sloshing load generated inside the tank during operation, the first support 150 and the second support are installed on the left and right sides or front and rear of the storage tank 100. Of course, additional supports 160 can be placed.

The penetrating portion formed within the storage tank 100 continuously penetrates the primary barrier 110 and the partition structure 120 for the operation of various sensors and equipment provided inside the primary barrier 110 and the transfer of cargo. The part connected to the outside of the tank, various sensors provided in the space between the primary barrier 110 and the partition structure 120, filling of the insulation material, and piping to realize the internal environment such as vacuum, etc., form the partition structure 120. It may include a part that penetrates and connects to the outside of the tank, and at this time, the auxiliary insulation layer 140 may penetrate together.

A typical configuration that connects from the outside of the storage tank 100 through the auxiliary insulation layer 140, the partition structure 120, and the primary barrier 110 to the internal space of the primary barrier 110 is liquefaction into the tank. An inner tank cooling line that prevents evaporation of liquefied hydrogen by spraying a small amount of liquefied hydrogen into the upper space of the tank inner tank formed by the loading/unloading pipe (L1) used to load/unload hydrogen and the primary barrier 110. (L2), an evaporative gas discharge pipe (L3) that discharges evaporative gas generated in the tank inner space formed by the primary barrier 110, and various sensors and electric field equipment installed inside the primary barrier 110. A sensor and electric field line (L4) connected to can be mentioned. The sensor and electric field line (L4) can be extended to the space between the primary barrier 110 and the partition structure 120 and connected to various sensors and electric field equipment installed in the space. When penetrating the primary barrier 110, which directly seals the liquefied gas, the airtightness of the penetration part must be maintained through welding, etc.

In addition, a representative configuration that penetrates the auxiliary insulation layer 140 and the partition structure 120 from the outside of the storage tank 100 and is connected to the space between the primary barrier 110 and the partition structure 120 is the vacuum as described above. A line (VL) can be mentioned.

The liquefied hydrogen storage tank 100 according to the present invention may be provided as a pressurized tank, and more preferably, may be provided as a Type C independent tank specified by IMO. Based on the standards stipulated by IMO, tanks designed with a design vapor pressure of 0.7 barg or higher can be classified as pressurized tanks.

The liquefied hydrogen storage tank 100 according to the present invention can be mounted on a ship, such as a liquefied hydrogen carrier, and used for long-distance transport of hydrogen through the sea. In addition, the technical idea of the present invention is not only to ships with self-propulsion capabilities, such as liquefied hydrogen carriers, but also to various floating marine structures floating on the sea even if they do not have self-propulsion capabilities if they are to store liquefied hydrogen at sea for a considerable period of time. can be applied to

The liquefied hydrogen storage tank 100 according to the present invention described above can minimize the loss rate of liquefied hydrogen due to heat intrusion by securing excellent insulation performance through the implementation of vacuum insulation, and ultimately hydrogen through the sea. It has the economic effect of significantly reducing the evaporation rate (BOG; Boil-Off Rate) of liquefied hydrogen and minimizing energy loss during long-distance transportation.

Meanwhile, the present invention is also characterized by a procedure and method for implementing a vacuum environment of the vacuum insulation layer 130 formed between the primary barrier 110 and the partition structure 120, with reference to FIGS. 4 and 5 below. The method of implementing vacuum insulation of the liquefied hydrogen storage tank 100 according to the present invention will be described in detail.

Figure 4 is a flowchart showing a method of implementing vacuum insulation of a liquefied hydrogen storage tank according to an embodiment of the present invention, and Figure 5 is a flowchart showing a method of implementing vacuum insulation of a liquefied hydrogen storage tank according to another embodiment of the present invention.

Referring to Figure 4, the method of implementing vacuum insulation of the liquefied hydrogen storage tank 100 according to an embodiment of the present invention includes an insulation installation step (S100) of installing/filling an insulation material in the internal space of the vacuum insulation layer 130; A substitution step (S200) of removing moisture and oxygen by injecting a substitution gas into the internal space of the vacuum insulation layer 130; A vacuum forming step (S300) of forming the internal space of the vacuum insulation layer 130 with a vacuum; A loading preparation step (S400) in which preliminary work is performed including a process of pre-cooling the space in order to load cryogenic liquefied hydrogen into the internal space of the first barrier 110; An additional vacuum step (S500) in which an additional vacuum effect of the vacuum insulation layer 130 is achieved due to a decrease in the temperature of the primary barrier 110; And it may include a vacuum completion step (S600) in which the implementation of vacuum insulation of the liquefied hydrogen storage tank 100 is completed.

In the insulation installation step (S100), at least one of the above-described multi-layer thin film insulation material 131 or a powder-type insulation material may be installed/filled inside the vacuum insulation layer 130.

In the substitution step (S200), a process of removing moisture and oxygen is performed by injecting a substitution gas into the space before forming the interior of the vacuum insulation layer 130 into a vacuum.

Here, the substitution gas undergoes a phase change from 'gas to liquid', 'gas to solid', or 'gas to liquid and solid' at an absolute pressure of 3 bar or less, and has a higher phase change temperature compared to hydrogen (H ₂ ). Preferably, a gas having a phase change temperature of -100°C or higher can be used, and a gas that satisfies the conditions includes carbon dioxide (CO ₂ ).

The substitution gas may be filled in the space inside the vacuum insulation layer 130 below the allowable pressure, and the inside of the vacuum insulation layer 130 is to prevent sensors and equipment from being affected by the phase-changed substitution gas (liquid or solid phase). Avoidance design may be included.

When the replacement of the internal space of the vacuum insulation layer 130 is completed, the air inside the vacuum insulation layer 130 is extracted in the vacuum forming step (S300) to create a vacuum environment. This vacuum creation operation can be performed using the vacuum pump (VP) and vacuum line (VL) described above.

The loading preparation step (S400) is a step of performing preliminary work to actually load liquefied hydrogen inside the primary barrier 110. This preliminary work includes the process of replacing the inside of the primary barrier 110 with inert gas, It may include a process of spraying a small amount of liquid hydrogen inside the primary barrier 110 to pre-cool the inner tank (commonly called 'cool down').

Meanwhile, in the loading preparation step (S400), as the interior of the primary barrier 110 is pre-cooled, the temperature of the primary barrier 110 decreases, and as a result, an additional vacuum effect of the vacuum insulation layer 130 can be obtained. Below, we will look in more detail at the principle by which the effect of additional vacuum is achieved.

First, as the temperature of the primary barrier 110 decreases, the temperature of the vacuum insulation space of the vacuum insulation layer 130 located immediately outside the primary barrier 110 also decreases, and accordingly, the vacuum insulation layer 130 Because the internal pressure is reduced, an additional vacuum effect can be obtained (S510).

In addition, as the temperature of the vacuum insulation layer 130 decreases, a phase change occurs in the remaining substitution gas remaining inside the vacuum insulation layer 130. Another additional change occurs through the pressure change that occurs when the phase change of the substitution gas occurs. More vacuum effect can be obtained (S520). In order to achieve this effect, the nature of the substitution gas injected into the vacuum insulation layer 130 in the previous substitution step (S200) is changed to "a phase change occurs from gas to liquid and/or solid at an absolute pressure of 3 bar or less, and the phase change temperature is - It is worth noting that it was selected as “higher than 100℃.”

As described above, the vacuum insulation of the liquefied hydrogen storage tank 100 according to the present invention is achieved while obtaining an additional vacuum effect through the pressure change due to the temperature drop of the primary barrier 110 and the pressure change due to the phase change of the replacement gas. It can be completed (S600).

Meanwhile, referring to FIG. 5, in the method of implementing vacuum insulation of the liquefied hydrogen storage tank 100 according to another embodiment of the present invention, the vacuum forming step (S300) is performed after the additional vacuum step (S500). There is a difference in

This is performed by alternating between the 'vacuum' process in the vacuum forming step (S300) and the 'cooling' process in the loading preparation step (S400), and is responsible for the cooling of the primary barrier 110 and the phase change of the substitution gas. The only difference is whether to receive the additional vacuum effect later or before vacuuming, and it is clear that additional vacuum effect can be obtained no matter which option is followed.

According to the method of implementing vacuum insulation of the liquefied hydrogen storage tank 100 according to the present invention described above, in addition to the configuration of the vacuum insulation space of the vacuum insulation layer 130, a replacement gas with a relatively high phase change temperature is added to the vacuum insulation space. By using it in the substitution process, it is possible to more effectively create a vacuum environment by using the additional pressure change due to the temperature change of the primary barrier 110 and the phase change of the substitution gas when creating a vacuum in the corresponding space.

In particular, as the capacity of the storage tank 100 increases, vacuum work takes a lot of time. When applying the present invention, the time required for vacuum work is reduced by utilizing the effect of additional vacuum (reduced pressure) to achieve the target insulation performance. It can be shortened.

In addition, in order to implement high vacuum, a plurality of vacuum means (pumps) are required depending on the degree of vacuum, but if the present invention is applied, the effect of additional vacuum (decompression) can be utilized to achieve the target vacuum level with only a single or relatively small number of vacuum means (pumps). It has the effect of enabling the implementation of .

The present invention is not limited to the described embodiments, and it is obvious to those skilled in the art that various modifications and changes can be made without departing from the spirit and scope of the present invention. Accordingly, such modifications or variations should be considered to fall within the scope of the claims of the present invention.

100: Liquefied hydrogen storage tank
110: Primary barrier
120: Compartment structure
130: Vacuum insulation layer
140: Auxiliary insulation layer
150: first support
160: second support
H: hull

Claims (16)

A primary barrier that performs airtightness while directly contacting the liquefied hydrogen stored inside;
a partition structure installed at a certain distance from the outside of the primary barrier and forming a closed space between the primary barrier and the primary barrier; and
It includes a vacuum insulation layer prepared by forming the closed space with a vacuum,
Before vacuum work on the vacuum insulation layer is performed, the closed space is replaced with a purge gas for the purpose of removing moisture and oxygen,
Before or after vacuum work on the vacuum insulation layer is performed, a cool-down process is performed to pre-cool the internal space of the primary barrier by spraying a small amount of liquefied hydrogen,
A decrease in the temperature of the vacuum insulation layer due to a decrease in the temperature of the primary barrier, a decrease in the pressure of the vacuum insulation layer due to a decrease in the temperature of the vacuum insulation layer, and a phase change of the remaining substitution gas in the vacuum insulation layer due to a decrease in the temperature of the vacuum insulation layer. And characterized in that an additional vacuum effect on the vacuum insulation layer occurs due to the influence of a decrease in pressure of the vacuum insulation layer due to the phase change of the displacement gas,
Independent liquefied hydrogen storage tank with vacuum insulation layer. In claim 1,
The substitution gas is characterized in that it is a substance with a higher phase change temperature than hydrogen (H ₂ ).
Independent liquefied hydrogen storage tank with vacuum insulation layer. In claim 2,
The substitution gas is characterized in that it is a substance that undergoes a phase change from gas to liquid and/or solid at an absolute pressure of 3 bar or less and has a phase change temperature of -100°C or more.
Independent liquefied hydrogen storage tank with vacuum insulation layer. In claim 3,
Characterized in that the substitution gas is carbon dioxide (CO ₂ ).
Independent liquefied hydrogen storage tank with vacuum insulation layer. In claim 1,
Further comprising at least one of a multi-layer insulation disposed inside the vacuum insulation layer to surround the outer surface of the primary barrier and a powder-type insulation material filled in the internal space of the vacuum insulation layer,
Independent liquefied hydrogen storage tank with vacuum insulation layer. In claim 5,
The powder-type insulation material is characterized in that it is one of perlite, hollow glass microspheres, and aerogel.
Independent liquefied hydrogen storage tank with vacuum insulation layer. In claim 6,
The auxiliary insulation layer is characterized in that it is composed of one of a vacuum insulation panel, a foam-type organic insulation material containing polyurethane foam, and an inorganic insulation material containing glass wool,
Independent liquefied hydrogen storage tank with vacuum insulation layer. In claim 7,
a plurality of first supports installed between the primary barrier and the partition structure to support them while maintaining a constant distance between the two structures; and
Further comprising a plurality of second supports supporting the partition structure,
Independent liquefied hydrogen storage tank with vacuum insulation layer. A marine transportation means equipped with an independent liquefied hydrogen storage tank according to any one of claims 1 to 8. In claim 9,
The liquefied hydrogen storage tank is an IMO Type C tank,
Maritime transport. In claim 10,
Characterized in that the marine transportation means is a liquefied hydrogen carrier,
Maritime transport. It includes a primary barrier that is in direct contact with the liquefied hydrogen stored inside and performs airtightness, and a partition structure that is installed at a certain distance from the outside of the primary barrier and forms a closed space between the primary barrier and the primary barrier. In the independent liquefied hydrogen storage tank,
A substitution step of removing moisture and oxygen by injecting a substitution gas into the closed space;
A vacuum forming step of forming the closed space into a vacuum insulated space; and
It includes a loading preparation step of performing preliminary work including a cool-down process of spraying a small amount of liquefied hydrogen into the internal space of the first barrier to cool it in advance,
The loading preparation step is performed after the substitution step and before or after the vacuum forming step,
A decrease in the temperature of the vacuum insulated space due to a decrease in the temperature of the primary barrier that occurs in the loading preparation step, a decrease in the pressure of the vacuum insulated space due to a decrease in the temperature of the vacuum insulated space, and a decrease in the temperature of the vacuum insulated space. Characterized in that an additional vacuum effect occurs on the vacuum insulated space due to the phase change of the remaining substitution gas in the vacuum insulated space and the effect of the pressure reduction in the vacuum insulated space due to the phase change of the substituted gas.
Method of implementing vacuum insulation of an independent liquefied hydrogen storage tank including a vacuum insulation layer. In claim 12,
In the vacuum forming step, the space is made into the vacuum insulation space by removing the air in the closed space using a vacuum pump.
Method of implementing vacuum insulation of an independent liquefied hydrogen storage tank including a vacuum insulation layer. In claim 13,
The substitution gas is characterized in that it is a substance with a higher phase change temperature than hydrogen (H ₂ ).
Method of implementing vacuum insulation of an independent liquefied hydrogen storage tank including a vacuum insulation layer. In claim 14,
The substitution gas is characterized in that it is a substance that undergoes a phase change from gas to liquid and/or solid at an absolute pressure of 3 bar or less and has a phase change temperature of -100°C or more.
Method of implementing vacuum insulation of an independent liquefied hydrogen storage tank including a vacuum insulation layer. In claim 15,
Characterized in that the substitution gas is carbon dioxide (CO ₂ ).
Method of implementing vacuum insulation of an independent liquefied hydrogen storage tank including a vacuum insulation layer.

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