Liquefied gas storage tank

Abstract

To provide a liquefied storage gas tank capable of effectively storing liquefied gas.SOLUTION: A liquefied gas storage tank is provided, comprising a first shell that seals liquefied gas, and a thin layer and / or space containing a nanoporous material, where the thin layer and / or the space covers all or a part of an inside surface of the first shell and / or all or a part of an outside surface of the first shell.SELECTED DRAWING: Figure 1A

Description

[Technical Field]

[0001] The present disclosure relates to liquefied gas storage tanks. [Background technology]

[0002] Because liquids have a higher density than gases, it is more efficient to store and transport gas in a liquid (liquefied gas) state rather than in a gaseous state. For example, a trailer loaded with hydrogen gas at 200 atmospheres (20 MPa) can transport the fuel for approximately 50 fuel cell vehicles per trailer, whereas a trailer of the same size loaded with liquefied hydrogen can transport the fuel for approximately 230 hydrogen fuel cell vehicles per trailer. Therefore, storing gas in a liquefied gas state is a promising option when establishing a hydrogen supply chain, including the supply of hydrogen to hydrogen stations, for example.

[0003] When storing liquefied gas, boil-off gas (BOG) is generated due to natural heat input from the outside, and some of the liquefied gas is lost. In particular, the rate of BOG generation is high for liquefied gases with extremely low boiling points, such as liquefied hydrogen (boiling point 20.28 K) and liquefied helium (boiling point: 4.22 K). Therefore, when storing liquefied gas, it is important to reduce the rate of BOG generation.

[0004] Systems capable of reducing the rate of BOG production have been reported. For example, Patent Document 1 discloses a cryogenic storage system comprising a storage tank shell including a protective outer layer, an impermeable inner layer, and at least one intermediate insulating space between the outer and inner layers. The storage space inside the inner layer of the storage tank shell is completely filled with a nanoporous material that adsorbs liquefied gas. Because the nanoporous material can increase the apparent boiling point of the adsorbed liquefied gas, this cryogenic storage system can reduce the rate of BOG production from the stored liquefied gas. [Prior art documents] [Patent documents]

[0005] [Patent Document 1] U.S. Patent Application Publication No. 2006 / 0218940 Summary of the Invention [Problem to be solved by the invention]

[0006] As mentioned above, to effectively store liquefied gas, it is important to reduce the rate of BOG generation. Furthermore, the rate of BOG generation can be reduced by using nanoporous materials as a storage medium for liquefied gas. In this case, the liquefied gas adsorbed in the nanoporous material cannot be extracted in its liquid state; it must be extracted by vaporization. This requires additional equipment, such as a heater, to heat the nanoporous material. Furthermore, nanoporous materials can only store a small amount of cryogenic liquid per volume, making it difficult to efficiently store large amounts of liquefied gas. In view of these circumstances, an object of the present disclosure is to provide a liquefied gas storage tank that can effectively store liquefied gas. [Means for solving the problem]

[0007] The present inventors have discovered that liquefied gas can be effectively stored by using a nanoporous material that adsorbs liquefied gas, and have completed the present invention. That is, the present disclosure provides, for example, a liquefied gas storage tank comprising a first shell that seals in liquefied gas and a thin layer and / or space containing a nanoporous material, wherein the thin layer and / or the space covers all or part of the inner surface of the first shell and / or all or part of the outer surface of the first shell. [Effects of the Invention]

[0008] The liquefied gas storage tank according to the present disclosure can effectively store liquefied gas. [Brief explanation of the drawings]

[0009] [Figure 1] 1A and 1B show a configuration example of a liquefied gas storage tank according to the first embodiment. [Figure 2] FIG. 2 shows an example of the configuration of a liquefied gas storage tank according to the second embodiment. [Figure 3] 3A and 3B show a configuration example of a liquefied gas storage tank according to a third embodiment. [Figure 4] 4A and 4B show a configuration example of a liquefied gas storage tank according to the fourth embodiment. [Figure 5] Figure 5 shows the H adsorption and desorption isotherms plotted based on the single-site Freundlich-Langmuir model for superactivated carbon (MSC-30), metal-organic framework (MOF-177), graphene (graphene nanoplatelets), and activated carbon (RX1.5 Extra) at 77, 67, and 57 K. [Figure 6] Figure 6 shows the relationship between the surface coverage q (mmol / g) and the adsorption enthalpy ΔHads (kJ / mol) for superactivated carbon MSC-30, metal-organic framework MOF-177, graphene nanoplatelets, and activated carbon RX1.5 Extra. DETAILED DESCRIPTION OF THE INVENTION

[0010] Hereinafter, embodiments of the present disclosure will be described with reference to the drawings. However, the scope of the present disclosure is not limited to the embodiments described herein, and various modifications may be made without departing from the spirit of the present disclosure. That is, the liquefied gas storage tank according to the present invention may not include some of the components of the liquefied gas storage tank shown in the drawings, or may include additional components. Non-limiting examples of additional components include an inlet / outlet for liquefied gas, a thermometer for measuring the temperature of the liquefied gas, and a pressure gauge for measuring the pressure of the liquefied gas. When a particular description given for one embodiment is applicable to other embodiments, that description may be omitted in the other embodiments.

[0011] [Terminology] (liquefied gas) In this disclosure, "liquefied gas" refers to a gas of substance having a boiling point of 40°C or less at atmospheric pressure and that is currently in a liquid state. Liquefied gases are typically gases that have a cryogenic boiling point that has been liquefied. Non-limiting examples of liquefied gases include liquefied hydrogen (boiling point: 20.28 K), liquefied helium (boiling point: 4.22 K), liquefied nitrogen (boiling point: 77.36 K), liquefied oxygen (boiling point: 90.19 K), liquefied argon (boiling point: 87.3 K), liquefied air (boiling point: 78.8 K), and liquefied natural gas. Liquefied natural gas typically contains liquefied methane (boiling point: 111.6 K) as a primary component.

[0012] (nanoporous materials) In the present disclosure, a "nanoporous material" is a material having pores whose pore sizes are preferably expressed on the nanometer scale. The pores of the nanoporous material are preferably composed of micropores, mesopores, macropores, or a combination thereof. Micropores, mesopores, and macropores preferably refer to pores with a pore diameter of 2 nm or less, pores with a pore diameter of 2 to 50 nm, and pores with a pore diameter of 50 nm or more, respectively.

[0013] The pore size of the nanoporous material is preferably 0.1 to 40 nm, more preferably 0.3 to 5 nm, and is preferably the average pore diameter (4V / A). The specific surface area of ​​the nanoporous material is preferably 200 to 7500 m 2 / g, more preferably 1000 to 7500m 2 / g.

[0014] Nanoporous materials generally have low thermal conductivity and can therefore act as thermal insulators.

[0015] The nanoporous material is capable of adsorbing a liquefied gas, but the nanoporous material may be used with or without adsorbing a liquefied gas. When the liquefied gas is liquefied hydrogen, the nanoporous material that has adsorbed the liquefied gas can function as a catalyst for the endothermic reaction that converts hydrogen molecules (H2) from parahydrogen to orthohydrogen. The nanoporous material preferably has a high adsorption capacity for the liquefied gas. Furthermore, the nanoporous material preferably can uniformly adsorb the liquefied gas. Furthermore, the nanoporous material preferably has a high heat of adsorption of the liquefied gas.

[0016] The nanoporous material includes a porous component, which is preferably composed of carbon, silicon, boron nitride, silica, titania, alumina, zinc oxide, or a combination thereof, and more preferably composed of superactivated carbon, activated carbon, graphene, metal organic frameworks, coordination polymers, silica aerogel, mesoporous silica, or zeolite.

[0017] The nanoporous material may contain a non-porous component in addition to the porous component described above. In this case, the content of the non-porous component may be preferably 0 to 50 wt %, more preferably 0 to 30 wt %, based on the total weight of the nanoporous material.

[0018] The nanoporous material may have any shape as long as the effects of the present invention can be obtained, such as a thin layer, powder, granules, or pellets. The thin layer comprising the nanoporous material may be a thin layer comprising the nanoporous material in the form of a thin layer, powder, granules, pellets, or the like. The space containing the nanoporous material may be a space containing the nanoporous material in the form of a thin layer, powder, granules, pellets, etc. The space containing the nanoporous material is preferably a space sandwiched between two shells. One or both of these two shells may have a part or all of the surface facing the space covered with a thin layer containing the nanoporous material.

[0019] (Insulation material) As the heat insulating material in the present disclosure, any heat insulating material can be used as long as the effects of the present invention can be obtained. The insulating material may be a standard insulating material. Non-limiting examples of standard insulating materials include vacuum insulation, perlite, aerogel, multi-layer insulation (MLI), and glass bubbles. In this disclosure, standard insulating materials do not include the nanoporous materials mentioned above, unless otherwise specified. The insulating material may also be the nanoporous material described above. The nanoporous material may be used with or without adsorbing a liquefied gas. The insulating material can be filled into the space containing the insulating material. In this case, the space containing the insulating material can function as an insulating space.

[0020] [Embodiment 1] An example of the configuration of a liquefied gas storage tank according to the first embodiment is shown in FIGS. 1A and 1B. The liquefied gas storage tank shown in FIG. 1A comprises a shell 103 that seals in a liquefied gas 101 and a thin layer 102 comprising a nanoporous material, the thin layer 102 coating the inner surface of the shell 103. 1A further comprises a shell 105 outside the shell 103, and a space 104 between the shell 103 and the shell 105. The space 104 is filled with a standard insulating material.

[0021] 1A stores liquefied gas 101 by sealing the liquefied gas 101. The liquefied gas 101 comes into contact with a thin layer 102 made of a nanoporous material that coats the inner surface of a shell 103, and as a result, a portion of the liquefied gas 101 is adsorbed onto the thin layer 102. In other words, the surface of the liquefied gas 101 stored in the liquefied gas storage tank is covered with the thin layer 102 to which a portion of the liquefied gas 101 is adsorbed.

[0022] Nanoporous materials can adsorb liquefied gases and thereby reduce the vapor pressure of the liquefied gases. The nanoporous material can lower its temperature due to the heat of desorption generated when the adsorbed liquefied gas is desorbed. When the liquefied gas is liquefied hydrogen, the nanoporous material can function as a catalyst for the endothermic reaction that converts hydrogen molecules (H2) from para-hydrogen to ortho-hydrogen. Therefore, when liquefied hydrogen adsorbed in a nanoporous material is heated by external heat, the nanoporous material can slow down the heating rate by catalyzing the endothermic reaction that converts the adsorbed hydrogen molecules (H2) from para-hydrogen to ortho-hydrogen. Since nanoporous materials have low thermal conductivity, the thin layer 102 made of nanoporous material can function as a heat insulator that insulates the liquefied gas 101 . Therefore, the liquefied gas storage tank shown in FIG. 1A can effectively reduce the rate of BOG generation because the thin layer 102 containing the nanoporous material covers the liquefied gas 101, thereby allowing the liquefied gas 101 to be stored effectively. In addition, in the liquefied gas storage tank shown in Figure 1A, most of the liquefied gas 101 is stored in a state that is not adsorbed in the nanoporous material, so most of the stored liquefied gas 101 can be removed while still in a liquid state.

[0023] The thickness of the thin layer 102 is preferably 1 nm to 500 mm, and more preferably 10 nm to 100 mm. Increasing the thickness of the thin layer 102 can further reduce the rate of BOG production, but increases the weight and cost of the liquefied gas storage tank. The thickness of the thin layer 102 is set appropriately in consideration of these circumstances depending on the application of the liquefied gas storage tank. For example, the thickness of the thin layer containing the nanoporous material can be set thinner for a liquefied gas storage tank for short-term storage and thicker for a liquefied gas storage tank for long-term storage. The thin layer 102 may consist of one layer or multiple layers.

[0024] The liquefied gas storage tank shown in FIG. 1A can further effectively reduce the rate of BOG production because the space 104 filled with standard insulation further covers the liquefied gas 101.

[0025] The liquefied gas storage tank shown in Fig. 1B has a configuration similar to that of the liquefied gas storage tank shown in Fig. 1A, except that it does not have a space corresponding to space 104. Therefore, the liquefied gas storage tank shown in Fig. 1B can effectively reduce the rate of BOG generation, similar to the liquefied gas storage tank shown in Fig. 1A, and thereby can effectively store liquefied gas. On the other hand, the liquefied gas storage tank shown in FIG. 1B does not have a space equivalent to space 104 compared to the liquefied gas storage tank shown in FIG. 1A, thereby reducing weight, size, and cost.

[0026] [Embodiment 2] An example of the configuration of a liquefied gas storage tank according to the second embodiment is shown in FIG. The liquefied gas storage tank shown in Figure 2 comprises a shell 303 that encloses a liquefied gas 301, and a thin layer 302 including a nanoporous material, the thin layer 302 covering a portion of the inner surface of the shell 303. The liquefied gas 301 comes into contact with the thin layer 302, whereby a portion of the liquefied gas 301 is adsorbed onto the thin layer 302. The liquefied gas storage tank shown in Fig. 2 includes heat conductive parts 306 and 307 with high thermal conductivity. The heat conductive parts 306 and 307 are, for example, metal parts for supporting the liquefied gas storage tank. The thin layer 302 covers all or part of the parts of the inner surface of the shell 303 that are prone to become hot. For example, in FIG. 2 , the thin layer 302 covers the parts near the heat-conductive components 306 and 307, which are prone to become hot due to conduction of external temperature through the heat-conductive components 306 and 307. Examples of parts of the inner surface of the shell 303 that are prone to become hot include the parts near the heat-conductive components 306 and 307, as well as the parts near the liquefied gas inlet / outlet and parts with a large specific surface area per unit volume. That is, in the liquefied gas storage tank of the present disclosure, the thin layer made of a nanoporous material may partially cover all or part of the parts of the inner part of the shell that stores the liquefied gas that are prone to become hot.

[0027] The liquefied gas storage tank shown in Fig. 2 further includes a shell 305 on the outside of the shell 303, and a space 304 between the shells 303 and 305. The space 304 may be filled with a standard insulating material as an insulating material, or may be filled with a liquefied gas and the above-mentioned nanoporous material.

[0028] Shell 303 has a similar configuration to shell 103 described above. Shell 305 has a similar construction to shell 105 described above.

[0029] The liquefied gas storage tank shown in Figure 2 can effectively reduce the rate of BOG generation, similar to the liquefied gas storage tank shown in Figure 1A described above, because the liquefied gas storage tank shown in Figure 2 has a thin layer 302 containing a nanoporous material covering the liquefied gas 301, thereby allowing the liquefied gas 301 to be stored effectively. On the other hand, in the liquefied gas storage tank shown in Figure 2, the thin layer 302 only partially covers the part of the inner surface of the shell 303 that is prone to high temperatures, thereby reducing the weight and cost of the liquefied gas storage tank compared to when the entire inner surface is covered. Furthermore, the liquefied gas storage tank shown in FIG. 2 can further effectively reduce the rate of BOG generation because the space 304 containing the insulating material further covers the liquefied gas 301.

[0030] [Embodiment 3] An example of the configuration of a liquefied gas storage tank according to the third embodiment is shown in FIGS. 3A and 3B. 3A includes a shell 402 that seals in liquefied gas 401 and a space 403 containing a nanoporous material, and space 403 covers the outer surface of shell 402. Here, space 403 is a space sandwiched between shell 402 and shell 404 that is disposed outside shell 402. Liquefied gas is introduced into the space 403 containing the nanoporous material at the same time as, before or after, the liquefied gas 401 is introduced into the shell 402, so that the nanoporous material contained in the space 403 adsorbs the liquefied gas. 3A further comprises a shell 406 outside the shell 404, and a space 405 between the shell 404 and the shell 406. The space 405 is filled with a standard insulating material.

[0031] Shells 402 and 404 have the same configuration as shell 103 described above. Shell 406 has a similar configuration to shell 105 described above.

[0032] The liquefied gas storage tank shown in Figure 3A can effectively reduce the rate of BOG generation, similar to the liquefied gas storage tank shown in Figure 1A described above, because the space 403 containing the nanoporous material covers the liquefied gas 401, thereby allowing the liquefied gas 401 to be stored effectively. In addition, the liquefied gas storage tank shown in FIG. 3A can further effectively reduce the rate of BOG production because the space 405 filled with standard insulation further covers the liquefied gas 401.

[0033] The liquefied gas storage tank shown in FIG. 3B requires a similar configuration to the liquefied gas storage tank shown in FIG. 3A, except that it does not have a shell corresponding to shell 406 and a space corresponding to space 405. Therefore, the liquefied gas storage tank shown in Figure 3B can effectively reduce the rate of BOG generation, similar to the liquefied gas storage tank shown in Figure 3A, thereby allowing the liquefied gas to be stored effectively. On the other hand, the liquefied gas storage tank shown in FIG. 3B can reduce weight, size, and cost compared to the liquefied gas storage tank shown in FIG. 3A.

[0034] [Embodiment 4] An example of the configuration of a liquefied gas storage tank according to the fourth embodiment is shown in FIGS. 4A and 4B. 4A includes a shell 602 that seals in liquefied gas 601, and a shell 606 that is disposed outside shell 602. The outer surface of shell 602 and the inner surface of shell 606 are coated with thin layers 603 and 605, respectively, made of nanoporous material. That is, the space between shell 602 and shell 606 is a space containing the nanoporous material. Liquefied gas 604 is introduced into the space containing the nanoporous material at the same time as, before or after liquefied gas 601 is introduced into shell 602. Liquefied gas 604 thus comes into contact with thin layers 603 and 605, causing a portion of liquefied gas 604 to adsorb onto thin layers 603 and 605. 4A further comprises a shell 608 outside the shell 606, and a space 607 between the shells 606 and 608. The space 607 is filled with a standard insulating material.

[0035] In the liquefied gas storage tank shown in Figure 4A, the space containing the nanoporous material covers the liquefied gas 601, so that the liquefied gas 601 can effectively reduce the rate of BOG generation, similar to the liquefied gas storage tank shown in Figure 1A described above, and thereby the liquefied gas 601 can be effectively stored. In addition, the liquefied gas storage tank shown in FIG. 4A can further effectively reduce the rate of BOG production because the space 607 filled with standard insulation further covers the liquefied gas 601.

[0036] The liquefied gas storage tank shown in Fig. 4B requires a configuration similar to that of the liquefied gas storage tank shown in Fig. 4A, except that it does not have a shell corresponding to shell 608 or a space corresponding to space 607. Therefore, the liquefied gas storage tank shown in Fig. 4B can effectively reduce the rate of BOG generation, similar to the liquefied gas storage tank shown in Fig. 4A, and thereby can effectively store liquefied gas. On the other hand, the liquefied gas storage tank shown in FIG. 4B can reduce weight, size, and cost compared to the liquefied gas storage tank shown in FIG. 4A.

[0037] A non-limiting list of exemplary embodiments of the present disclosure and combinations thereof is disclosed below. [1] A liquefied gas storage tank comprising a first shell that seals in liquefied gas and a thin layer and / or space containing a nanoporous material, wherein the thin layer and / or the space covers all or part of the inner surface of the first shell and / or all or part of the outer surface of the first shell. [2] The liquefied gas storage tank described in [1], wherein the nanoporous material adsorbs the liquefied gas. [3] A liquefied gas storage tank according to [1] or [2], wherein the liquefied gas is liquefied hydrogen, liquefied helium, liquefied nitrogen, liquefied oxygen, liquefied argon, liquefied air, or liquefied natural gas. [4] A liquefied gas storage tank as described in any one of [1] to [3], further comprising a second shell on the outside of the first shell to protect the liquefied gas storage tank. [5] A liquefied gas storage tank as described in [4], having a space containing insulating material between the first shell and the second shell. [6] The specific surface area of ​​the nanoporous material is 200 to 7500 m 2 / g, [1] to [5]. A liquefied gas storage tank according to any one of [1] to [5]. [7] A liquefied gas storage tank according to any one of [1] to [6], wherein the pores of the nanoporous material have a pore size of 0.1 to 40 nm. [8] A liquefied gas storage tank according to any one of [1] to [7], wherein the nanoporous material comprises a porous component comprising one or more selected from carbon, silicon, boron nitride, silica, titania, alumina, zinc oxide, and combinations thereof. [9] The liquefied gas storage tank according to any one of [1] to [8], wherein the nanoporous material comprises one or more porous components selected from the group consisting of superactivated carbon, activated carbon, graphene, metal-organic framework, metal-organic framework, silica aerogel, mesoporous silica, and zeolite. [Example]

[0038] The present invention will be further described below with reference to examples, but these examples are not intended to limit the scope of the present invention. Commercially available reagents and equipment referred to in the examples were used according to the manufacturer's instructions or standard procedures, unless otherwise specified.

[0039] [Example 1] Interaction of nanoporous materials with liquefied gases To verify that the liquefied gas storage tank of the present disclosure can reduce the rate of BOG production, the interaction between the nanoporous material and the liquefied gas was analyzed. Specifically, using (a) superactivated carbon MSC-30, (b) metal-organic framework MOF-177, (c) graphene nanoplatelets, and (d) activated carbon RX1.5 Extra as examples of nanoporous materials, H adsorption / desorption isotherms at 77 K, 67 K, and 57 K were generated based on the single-site Freundlich-Langmuir model. The results are shown in Figure 5. The parameters of the single-site Freundlich-Langmuir model are listed in Table 1.

[0040] [Table 1]

[0041] As shown in FIG. 5 and Table 1, superactivated carbon, metal-organic framework, graphene, and activated carbon all effectively adsorbed liquefied hydrogen.

[0042] Next, using the parameters of the single-site Freundlich-Langmuir model shown in Table 1, the amount of H2 adsorbed q (mmol / g) and the heat of adsorption -H ads The relationship between the ion concentration and the ion density (kJ / mol) was plotted, and the results are shown in Figure 6.

[0043] As shown in Figure 6, the superactivated carbon, metal-organic framework, graphene, and activated carbon all had high heats of adsorption relative to the amount of H2 adsorbed. Here, the change in heat of adsorption Δ-H ads and the change in the heat of desorption Δ-H des The relationship between Δ-Hads =-Δ-H des This result indicates that a large amount of heat is absorbed when a liquefied gas is desorbed from a nanoporous material. Therefore, nanoporous materials exhibit high heat absorption when a liquefied gas evaporates (i.e., when a liquefied gas is desorbed from a nanoporous material), which can increase the apparent boiling point of the liquefied gas. Furthermore, as shown in Figure 6, the heats of adsorption for the superactivated carbon, metal-organic framework, graphene, and activated carbon were relatively uniform across a wide range of H adsorption amounts, indicating that these nanoporous materials can stably adsorb liquefied gases regardless of the H adsorption amount. These results show that the liquefied gas storage tank of the present invention can effectively reduce the rate of BOG generation. [Explanation of symbols]

[0044] 101, 201, 301, 401, 501, 601, 604, 701, 704 Liquefied gas 102, 202, 302, 603, 605, 703, 705 thin layer 103, 105, 203, 204, 303, 305, 402, 404, 406, 502, 504, 602, 606, 608, 702, 706 Shell 104, 304, 403, 405, 503, 607 space 306, 307, Heat conductive parts

Claims

1. A liquefied gas storage tank comprising a first shell that seals in liquefied gas and a thin layer and / or space containing a nanoporous material, the thin layer and / or the space covering all or part of the inner surface of the first shell and / or all or part of the outer surface of the first shell.

2. 10. The liquefied gas storage tank of claim 1, wherein the nanoporous material adsorbs the liquefied gas.

3. 3. The liquefied gas storage tank according to claim 1 or 2, wherein the liquefied gas is liquefied hydrogen, liquefied helium, liquefied nitrogen, liquefied oxygen, liquefied argon, liquefied air, or liquefied natural gas.

4. 3. The liquefied gas storage tank according to claim 1, further comprising a second shell outside the first shell for protecting the liquefied gas storage tank.

5. 5. The liquefied gas storage tank of claim 4, further comprising a space between the first shell and the second shell containing a thermal insulator.

6. The specific surface area of ​​the nanoporous material is 200 to 7500 m ２ 3. The liquefied gas storage tank according to claim 1 or 2, wherein the solubility is 1 / g.

7. The liquefied gas storage tank according to claim 1 or 2, wherein the pore diameter of the pores of the nanoporous material is 0.1 to 40 nm.

8. 3. The liquefied gas storage tank of claim 1 or 2, wherein the nanoporous material comprises a porous component comprising one or more selected from carbon, silicon, boron nitride, silica, titania, alumina, zinc oxide, and combinations thereof.

9. 3. The liquefied gas storage tank of claim 1, wherein the nanoporous material comprises one or more porous components selected from the group consisting of superactivated carbon, activated carbon, graphene, metal organic frameworks, metal organic frameworks, silica aerogels, mesoporous silica, and zeolites.

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