KR20240041146A - Liquid hydrogen storage and transportation systems - Google Patents

Abstract

As the liquid hydrogen storage and transportation system includes a physisorption-type adsorbent containing pores (voids) that satisfy a certain maximum diameter and pore volume, the physisorption-type adsorbent not only has a high maximum saturated adsorption amount, but also has a high volumetric adsorption capacity. , it has the advantage of having a high desorption temperature of hydrogen. Therefore, it is possible to use liquid hydrogen commercially for long-distance continental transportation by utilizing a storage and transportation system that satisfies these characteristics.

Description

Liquid hydrogen storage and transportation systems}

It relates to a storage and transportation system for liquid hydrogen.

Hydrogen fuel is gaining attention as a sustainable and clean alternative to fossil-based energy. However, utilizing hydrogen as a fuel requires efficient and reliable storage and delivery technology.

In particular, liquid hydrogen has a lower risk of explosion, higher ease of delivery, and lower distribution costs than gaseous hydrogen, so the need for storage and delivery technology for liquid hydrogen is increasing.

However, liquid hydrogen has a low boiling point, so in the case of existing liquid hydrogen (LH ₂ ) containers and liquid hydrogen (LH ₂ ) tanks, liquid hydrogen ( _{LH 2} ) evaporates quickly due to inevitable heat inflow. There was a problem that not only did the internal pressure of the liquid hydrogen (LH ₂ ) tank increase, but evaporation loss also increased.

Republic of Korea Patent Publication No. 10-1330167

A physical absorption type adsorbent having an appropriate pore diameter and volume inside a porous material, and a storage container containing liquid hydrogen (LH ₂ ), wherein the physical absorption type adsorbent and the liquid The purpose is to provide a storage and transportation system for liquid hydrogen that allows efficient storage/transportation even at a temperature higher than the hydrogen liquefaction temperature by physically adsorbing hydrogen (LH ₂ ) through Van der Waals interaction. do.

A storage and transport system for liquid hydrogen according to one aspect includes a physical adsorption type adsorbent containing pores, and a storage container containing liquid hydrogen (LH ₂ ), wherein the physical adsorption The adsorbent and liquid hydrogen (LH ₂ ) are physically adsorbed by Van der Waals interaction, and the volume adsorption capacity ratio for liquid hydrogen (LH ₂ ) is determined by the liquid hydrogen (LH) of the empty storage container. ₂ ) It is characterized in that it is 85% to 110% based on 100% of the total volumetric adsorption capacity.

The physisorption-type adsorbent further includes an unsaturated metal site.

The maximum diameter of the pores of the physical adsorption type adsorbent is 0.5 nm to 20 nm.

The pore volume of the physisorption-type adsorbent is 59 volume% to 96 volume%, based on 100 volume% of the total physisorption-type adsorbent.

The desorption temperature of the physical adsorption type adsorbent is 25K or more.

The maximum saturation uptake of the physisorption-type adsorbent is 55 mmol/g to 120 mmol/g.

The crystal density of the physisorption-type adsorbent is 0.20 g/cc to 0.60 g/cc.

The volumetric uptake capacity of the physisorption-type adsorbent is 30 mol/L to 40 mol/L.

The liquid hydrogen storage and transportation system includes a physisorption-type adsorbent containing pores (voids) that satisfy an appropriate pore diameter (0.5-20 nm) and pore volume (80% or more), so that the maximum physisorption-type adsorbent It has the advantage of not only having a high saturated adsorption amount, but also a high volumetric adsorption capacity and a high desorption temperature of hydrogen. Therefore, it is possible to commercially utilize liquid hydrogen for long-distance continental transportation by utilizing a storage and transportation system that satisfies these characteristics.

Figure 1a is a schematic diagram of isochoric sorption measurement on an empty storage container without physisorption-type adsorbent.
Figure 1b is a schematic diagram of isochoric sorption measurement for a storage and transport system of liquid hydrogen.
Figure 2 is a graph showing the isochoric sorption measurement results of an empty storage vessel without a physisorption-type adsorbent and a storage and transport system for liquid hydrogen.
Figure 3 is a schematic diagram of isochoric sorption measurement by saturated adsorption of hydrogen under conditions at 20.3K in a liquid hydrogen storage and transport system.
Figure 4 is a graph showing the results of the adsorption isotherm after saturated adsorption of hydrogen under the condition of 1 bar 20.3K in the liquid hydrogen storage and transportation system.
Figures 5a to 5c show the liquid hydrogen storage and transport system and the hydrogen gas input amount of 50% (Figure 5a), 80% (Figure 5b), and 100% (Figure 5c) based on 100% of the storage capacity of the empty storage container. This is a graph of the isovolumetric desorption measurement results according to temperature.
Figure 6 is a graph showing the ratio results of the volumetric uptake capacity (cryo-adsorbed system) of the storage and transport system for liquid hydrogen compared to the total 100% liquid hydrogen storage capacity for 1 L of an empty storage container.
Figure 7a shows INS spectra for para-hydrogen bulk solid and para-hydrogen bulk liquid measured at 10K and 18K.
Figure 7b is the INS spectrum of the liquid hydrogen storage and transport system (DUT-6(Zn)) into which different amounts of para-hydrogen were added at 20K.
Figure 7c is a spectrum of INS intensity change according to the amount of para-hydrogen added in Figure 7b.

The above objects, other objects, features and advantages will be easily understood through the following preferred embodiments in conjunction with the accompanying drawings. However, it is not limited to the embodiments described here and may be embodied in other forms. Rather, the embodiments introduced herein are provided so that the disclosed content will be thorough and complete and the technical ideas can be sufficiently conveyed to those skilled in the art.

While describing each drawing, similar reference numerals are used for similar components. In the attached drawings, the dimensions of the structures are enlarged from the actual size for clarity of the present invention. Terms such as first, second, etc. may be used to describe various components, but the components should not be limited by the terms. The above terms are used only for the purpose of distinguishing one component from another. For example, a first component may be named a second component, and similarly, the second component may also be named a first component without departing from the scope of the present invention. Singular expressions include plural expressions unless the context clearly dictates otherwise.

In this specification, terms such as “comprise” or “have” are intended to designate the presence of features, numbers, steps, operations, components, parts, or combinations thereof described in the specification, but are not intended to indicate the presence of one or more other features. It should be understood that this does not exclude in advance the possibility of the existence or addition of elements, numbers, steps, operations, components, parts, or combinations thereof. Additionally, when a part of a layer, membrane, region, plate, etc. is said to be “on” another part, this includes not only being “directly above” the other part, but also cases where there is another part in between. Conversely, when a part of a layer, membrane, region, plate, etc. is said to be "underneath" another part, this includes not only being "immediately below" the other part, but also cases where there is another part in between.

Unless otherwise specified, all numbers, values, and/or expressions used herein expressing quantities of components, reaction conditions, polymer compositions, and formulations are intended to represent, among other things, how such numbers inherently occur in obtaining such values. Since they are approximations reflecting the various uncertainties of measurement, they should be understood in all cases as being qualified by the term "approximately". Additionally, where a numerical range is disclosed herein, such range is continuous and, unless otherwise indicated, includes all values from the minimum to the maximum of such range inclusively. Furthermore, when such range refers to an integer, all integers from the minimum value up to and including the maximum value are included, unless otherwise indicated.

In this specification, when a range is stated for a variable, the variable will be understood to include all values within the stated range, including the stated endpoints of the range. For example, the range "5 to 10" includes the values 5, 6, 7, 8, 9, and 10, as well as any subranges such as 6 to 10, 7 to 10, 6 to 9, 7 to 9, etc. It will be understood that it also includes any values between integers that fall within the scope of the stated range, such as 5.5, 6.5, 7.5, 5.5 to 8.5, and 6.5 to 9, etc. Also, for example, the range "10% to 30%" includes values such as 10%, 11%, 12%, 13%, etc. and all integers up to and including 30%, as well as 10% to 15%, 12% to 12%, etc. It will be understood that it includes any subranges, such as 18%, 20% to 30%, etc., and any value between reasonable integers within the range of the stated range, such as 10.5%, 15.5%, 25.5%, etc.

In the case of existing liquid hydrogen (LH ₂ ) containers and liquid hydrogen (LH ₂ ) tanks, the boiling point of liquid hydrogen is low _{, so if heat is inevitably introduced, the liquid hydrogen (LH 2 )} vaporizes quickly and There was a problem that not only did the internal pressure of the liquid hydrogen (LH ₂ ) tank increase, but evaporation loss also increased.

Accordingly, the present inventors conducted intensive research to solve the above problem, and as a result, a liquid containing a physisorption-type adsorbent containing pores (voids) satisfying the appropriate pore diameter (0.5-20 nm) and pore volume (80% or more) was obtained. It was discovered and completed that the physisorption-type adsorbent has the advantages of high maximum saturated adsorption capacity, high volumetric adsorption capacity, and high desorption temperature of hydrogen in a hydrogen storage and transportation system.

A storage and transportation system for liquid hydrogen according to one aspect includes a physical absorption type adsorbent containing pores, and a storage container containing liquid hydrogen (LH ₂ ). In particular, the physisorption-type adsorbent and liquid hydrogen (LH ₂ ) are characterized in that they are physically adsorbed by Van der Waals interaction, and preferably, the volume relative to the liquid hydrogen (LH ₂ ) is The adsorption capacity ratio may be 80% or more, based on 100% of the total volumetric adsorption capacity for liquid hydrogen (LH ₂ ) of the empty storage container.

According to one embodiment, the storage vessel may be a conventional storage vessel that can be used in a liquid hydrogen storage and transportation system. According to one embodiment, the volume of the storage container may be 1 m ³ to 50,000 m ³ . Outside the numerical range, if the volume of the storage container is too small, evaporation loss increases, and if the volume of the storage container is too large, a large amount of adsorbent is required and a lot of energy is consumed for liquefaction. Additionally, evaporation loss may vary depending on the heat transfer of the storage container.

According to one embodiment, liquid hydrogen (LH ₂ ) may be hydrogen liquefied by cooling gaseous hydrogen to a cryogenic temperature of -253.15°C or lower, preferably to -259.05°C to -252.87°C.

According to one embodiment, the physisorption type adsorbent is not particularly limited as long as it has a high volumetric adsorption capacity by efficiently adsorbing liquid hydrogen more than the skeleton volume occupied by the adsorbent, for example, MOF. -177 (microporous), MFU-4l (hierarchically microporous), DUT-6(Zn) (micro and mesoporous), MIL-53(Al) (a flexible framework), and MOF-74(Ni) (contains open metal sites) ) can be.

According to one embodiment, the maximum diameter of the pores of the physisorption-type adsorbent may be 0.5 nm to 20 nm. Outside the numerical range, if the maximum diameter is too small, there is a disadvantage of low internal diffusion, and if the maximum diameter is too large, there is a disadvantage of low physical adsorption. Additionally, the pore volume of the physisorption-type adsorbent may be 60 volume% to 96 volume% based on 100 volume% of the total physisorption-type adsorbent. If the pore volume is outside the numerical range and is too small, there is a disadvantage of low liquid hydrogen capacity and it is physically difficult to make the pore volume larger.

According to one embodiment, the physisorption type adsorbent may further include an unsaturated metal moiety capable of strong interaction. That is, in the case of a storage and transport system for liquid hydrogen, an adsorbent that satisfies a specific maximum diameter and pore volume and additionally contains an unsaturated metal binding site is included, so that the physisorption type adsorbent and liquid hydrogen (LH ₂ ) can be converted to van der Waals It has the advantage of excellent physical adsorption due to Van der Waals interaction.

According to one embodiment, when hydrogen is saturated adsorbed to a liquid hydrogen storage and transport system containing a physisorption-type adsorbent, an adsorption isotherm showing the adsorption behavior of a typical microporous material may appear, and the maximum saturated adsorption amount accordingly (maximum saturation uptakes) may be 15 mmol/g to 120 mmol/g, preferably 55 mmol/g to 120 mmol/g. According to one embodiment, the physisorption-type adsorbents DUT-6 (Zn), MOF-177, MFU-4l, MIL-53 (Al), and MOF-74 (Ni) included in the storage and transportation system of liquid hydrogen. The maximum saturated adsorption amounts were 88.4 mmol/g, 71.6 mmol/g, and 57.6 mmol/g for DUT-6(Zn), MOF-177, MFU-4l, MOF-74(Ni), and MIL-53(Al), respectively. g, 24.7 mmol/g, and 19.0 mmol/g.

According to one embodiment, the amount of hydrogen gas (H ₂ ) introduced into the liquid hydrogen storage and transport system is the hydrogen gas (H 2 ) introduced into the existing liquid hydrogen (LH ₂ ) container and liquid hydrogen (LH ₂ ) tank _. ) In order to maintain an appropriate desorption temperature while similar to the input amount, it may be 50% to 100%, preferably 50% to 80%, of the total 100% maximum saturated adsorption amount of the physisorption-type adsorbent.

According to one embodiment, the desorption temperature of the physisorption-type adsorbent included in the liquid hydrogen storage and transportation system is 80% to 80% of the amount of hydrogen gas (H ₂ ) introduced into the liquid hydrogen storage and transportation system. Depending on 100%, it may be 20K or more (higher than the desorption temperature of 12K of existing empty storage containers), preferably 30K or more, more preferably 33K to 45K. According to one embodiment, the physisorption-type adsorbents DUT-6 (Zn), MOF-177, MFU-4l, MIL-53 (Al), and MOF-74 (Ni) included in the storage and transportation system of liquid hydrogen. The desorption temperature may be 20 K, 24 K, 24 K, 33 K, and 45 K.

That is, in most liquid hydrogen storage and transport systems, the adsorption temperature increases by improving the interaction between H ₂ and the adsorbent by the adsorption energy by including an adsorbent that satisfies a specific maximum diameter and pore volume. In particular, the adsorbent In the case of a liquid hydrogen storage and transport system that further includes unsaturated metal binding sites, hydrogen-adsorbent interaction occurs more actively, so the desorption temperature is higher than that of existing liquid hydrogen (LH ₂ ) containers and liquid hydrogen (LH ₂ ) tanks. It has high characteristics.

According to one embodiment, the crystal density of the physisorption-type adsorbent included in the liquid hydrogen storage and transportation system may be 0.20 g/cc to 0.98 g/cc, and preferably, 0.20 g/cc to 0.20 g/cc. It may be 0.60g/cc.

According to one embodiment, the volumetric uptake capacity of the physisorption-type adsorbent may be determined based on the maximum saturated adsorption amount and crystal density based on 1L of storage container, and is preferably 18 mol/L to 40 mol/L. It may be, and more preferably, it may be 30 mol/L to 34 mol/L. Specifically, a storage and transport system for liquid hydrogen including physisorption-type adsorbents of each of DUT-6 (Zn), MFU-4l, MOF-177, MOF-74 (Ni), and MIL-53 (Al). Volumetric uptake capacity may be 33.6mol/L, 32.3mol/L, 30.8mol/L, 29.79mol/L, and 18.58mol/L, respectively.

Accordingly, the volumetric adsorption capacity ratio of the liquid hydrogen storage and transportation system containing the physisorption-type adsorbent is 35.2mol L-1 for the corresponding volume of 1L of the empty storage container, so if this is set to 100% overall, , Preferably, it may be 50% to 96%, and preferably, it may be 85% to 110%. Specifically, a storage and transport system for liquid hydrogen including physisorption-type adsorbents of each of DUT-6 (Zn), MFU-4l, MOF-177, MOF-74 (Ni), and MIL-53 (Al). The volume adsorption capacity ratios were 96% (33.6 mol/L), 92% (32.3 mol/L), 88% (30.8 mol/L), 85% (29.79 mol/L), and 53% (18.58 mol/L), respectively. L) may be.

In summary, even if the volumetric adsorption capacity ratio is high with a low crystal density and the highest maximum saturated adsorption capacity, an optimal system cannot be built if the desorption temperature is too small or the volumetric adsorption capacity is low even if the desorption temperature is high. Since the storage and transport system of liquid hydrogen includes an adsorbent that satisfies a certain maximum diameter and pore volume, the interaction between the adsorbent and hydrogen becomes larger compared to the attraction between hydrogen and hydrogen on the skeleton and surface of the physisorption type adsorbent. The adsorbent-hydrogen bond length is shorter than the hydrogen-hydrogen bond length, resulting in a higher hydrogen density near the adsorbent pore walls, which has the advantage of utilizing an optimal system with a relatively high volumetric adsorption capacity and a relatively high desorption temperature. .

Hereinafter, the present invention will be described in more detail through examples. However, these examples are for illustrative purposes only and the scope of the present invention is not limited to these examples.

Example 1: Preparation of a storage and transportation system for liquid hydrogen

Prepare a quartz sample cell as a storage container, and use physical absorption type adsorbents such as MOF-177 (microporous), MFU-4l (hierarchically microporous), DUT-6(Zn) (micro and mesoporous), and MIL-53(Al). ) (a flexible framework), and MOF-74(Ni) (contains open metal sites) were prepared, respectively. At this time, MOF-177 had a maximum pore diameter of 1.2 nm and a pore volume (void volume) of 83 volume% based on 100 volume% of the total physisorption-type adsorbent. In addition, MFU-4l had a maximum pore diameter of 0.9 nm and a pore volume (void volume) of 79% by volume based on 100% by volume of the total physisorption-type adsorbent. In addition, DUT-6 (Zn) had a maximum pore diameter of 2.3 nm and a pore volume (void volume) of 85% by volume based on 100% by volume of the total physisorption-type adsorbent. In addition, MIL-53(Al) had a maximum pore diameter of 0.8 nm and a pore volume (void volume) of 59 vol% based on 100 vol% of the total physisorption-type adsorbent. In addition, MOF-74(Ni) had a maximum pore diameter of 0.6 nm and a pore volume (void volume) of 71 volume% based on 100 volume% of the total physisorption-type adsorbent.

Experimental Example 1: Isochoric desorption measurement of liquid hydrogen storage and transport system

After preparing a liquid hydrogen storage and transport system and an empty storage container without a physisorption-type adsorbent as in Example 1, 760 mmHg (~1 bar) of hydrogen was introduced at room temperature (295 K) as shown in Figures 1a and 1b, etc. After volumetric desorption measurement (Isochoric sorption measurement), the results are shown in Figure 2.

Specifically, for isovolumetric desorption measurements, the connection valve was closed to ensure a constant volume, and after hydrogen was introduced, the system and vessel were cooled to 16K, respectively. Due to this, the pressure dropped from 16 K to 0 bar due to hydrogen condensation or complete adsorption. Meanwhile, the pressure inside the system and vessel was measured during cooling and heating, and at this time, the pressure of the vessel was measured at a ramping rate of 3K min ^-1 .

Specifically, Figure 1a is a schematic diagram of an isochoric desorption measurement for an empty storage vessel without a physisorption-type adsorbent, and Figure 1b is a schematic diagram of an isochoric desorption measurement for a storage and transport system of liquid hydrogen. ) This is a schematic diagram. In addition, Figure 2 is a graph showing the isochoric desorption measurement results of an empty storage vessel without a physisorption-type adsorbent and a liquid hydrogen storage and transport system.

Referring to FIGS. 1A, 1B, and 2, as a result of the isovolumetric desorption measurement, it was confirmed that an immediate phase transition occurred in the empty storage container as the temperature increased and was mostly completed at 20K. It was also confirmed that the increase in pressure after 20K was due to thermal expansion of H ₂ gas. In other words, it was confirmed that the rapid increase in pressure in the empty storage container is similar to _the H ₂ evaporation phenomenon in the existing liquid hydrogen (LH ₂ ) container and liquid hydrogen (LH ₂ ) tank. It was confirmed that liquid hydrogen (LH ₂ ) vaporizes due to the inevitable heat inflow from the (LH ₂ ) tank, increasing the internal pressure of the existing liquid hydrogen (LH ₂ ) container and liquid hydrogen (LH ₂ ) tank.

Meanwhile, in the case of a liquid hydrogen storage and transport system containing a physisorption-type adsorbent, the temperature corresponding to a pressure of 0 bar increases by more than ~35K in the isovolumetric process, and all show a graph pattern according to a similar isovolumetric process, with specific desorption The temperature was confirmed to increase in the order of empty containers, MFU-4l, DUT-6 (Zn), MOF-177, MIL-53 (Al), and MOF-74 (Ni).

Through this, it was confirmed that more energy is required for surface desorption of hydrogen gas molecules due to the strong van der Waals force between hydrogen gas molecules and the adsorbent surface, so desorption begins above the H ₂ critical point of 33K (Tc). , it was confirmed that the pressure profile gradually showed an S-shaped graph pattern at higher temperatures. Therefore, in the case of a liquid hydrogen storage and transport system, pressure expansion can be significantly suppressed by including an adsorbent that satisfies the specific maximum diameter and pore volume of the pores, so the pressure increases above 35K instead of the onset temperature of 12K in an empty storage vessel. It was confirmed that was measured.

Experimental Example 2: Comparison of storage capacity (maximum saturated adsorption capacity) through isotherms measurement of liquid hydrogen storage and transport system

After preparing a liquid hydrogen storage and transport system as in Example 1, hydrogen was saturated and adsorbed to evaluate the maximum storage capacity, that is, the maximum saturated adsorption capacity, based on the empty storage container and the upper limit of the physical storage capacity of the system.

At this time, the specific measurement process and measurement conditions were to saturately adsorb hydrogen at 20.3K (liquefaction temperature of H ₂ ) until the pressure reached 1 bar, then measure the adsorption isotherm, and the results are shown in Figure 4. In addition, saturation adsorption includes both surface adsorption and pore adsorption of the physisorption-type adsorbent, and the hydrogen storage capacity obtained at 1 bar and 20.3 K (liquefaction temperature of H ₂ ) was considered the physical upper limit of the absolute adsorption amount.

Specifically, Figure 3 is a schematic diagram of isochoric desorption measurement by saturated adsorption of hydrogen under conditions at 20.3K in a liquid hydrogen storage and transport system. In addition, Figure 4 is a graph showing the results of the adsorption isotherm after saturated adsorption of hydrogen under the conditions of 1 bar 20.3K in the liquid hydrogen storage and transportation system.

Referring to Figures 3 and 4, all liquid hydrogen storage and transport systems including MFU-4l, DUT-6 (Zn), MOF-177, and MIL-53 (Al), MOF-74 (Ni) are reversible. As it shows the phosphorus H2 isotherm, it can be confirmed that it shows type 1 adsorption behavior, and it can be confirmed that it shows the characteristics of a typical microporous material. Accordingly, the maximum saturation uptakes before liquefaction for H2 adsorption at 20.3K and 1bar are DUT-6(Zn), MOF-177, MFU-4l, MOF-74(Ni) and MIL-53( Al) were confirmed to be 88.4 mmol g ^-1 , 71.6 mmol g ^-1 , 57.6 mmol g ^-1 , 24.7 mmol g ^-1 , and 19.0 mmol g ^-1 , respectively.

Experimental Example 3: Comparison of isochoric desorption measurement according to change in hydrogen gas input ratio and temperature change with respect to storage capacity of liquid hydrogen storage and transportation system

It is mostly the same as Experimental Example 1, but after preparing a liquid hydrogen storage and transport system and an empty storage container without a physical adsorbent, the hydrogen gas input amount based on 100% of the storage capacity measured in Experimental Example 2 was applied to the cooled sample cell. 50%, 80%, and 100% were added respectively, and the pressure change according to temperature was measured by isochoric desorption measurement, and the results are shown in FIGS. 5A to 5C. At this time, the specific measurement process and conditions were mostly the same as those in Experimental Example 1.

Specifically, Figures 5a to 5c show the liquid hydrogen storage and transport system and the hydrogen gas input amount based on 100% of the storage capacity of the empty storage container at 50% (Figure 5a), 80% (Figure 5b), and 100% (Figure 5c). ) This is a graph of isovolumetric desorption measurement results according to temperature when added.

Referring to FIGS. 5A to 5C, in the case of an empty storage container, it was confirmed that the temperature rapidly increased as the temperature increased, quickly reaching 1 bar (760 mmHg), regardless of the amount of hydrogen gas input. Meanwhile, referring to Figure 5a, each of the liquid hydrogen storage and transport systems including MFU-4l, DUT-6 (Zn), MOF-177, and MIL-53 (Al), MOF-74 (Ni) In the case where hydrogen gas is injected as much as 50% of the storage capacity, the graph pattern gradually becomes S-shaped at higher temperatures only in the storage and transportation system of liquid hydrogen including MIL-53 (Al) and MOF-74 (Ni). It was confirmed that a graph pattern according to the isovolumetric process was shown, through which the amount of hydrogen gas input into the storage and transportation system of liquid hydrogen including MIL-53 (Al) and MOF-74 (Ni) was determined. This means that it is similar to the input amount of hydrogen of 760mmHg (~1bar) at room temperature (295K) as in 1.

In addition, referring to Figures 5b and 5c, the starting point of the desorption temperature is liquid hydrogen containing MFU-4l, DUT-6 (Zn), MOF-177, and MIL-53 (Al), MOF-74 (Ni) Based on 100% storage capacity of each storage and transportation system, it was confirmed that hydrogen gas decreases as the input amount increases (80% -> 100%), and as the hydrogen gas input amount increases, the starting point of the desorption temperature is when the empty storage container is. It was confirmed that it was close to the desorption temperature of .

Meanwhile, referring to Figure 5b, in the case of existing liquid hydrogen (LH ₂ ) containers and liquid hydrogen (LH ₂ ) tanks, 80% to 85% of hydrogen gas is generally input based on 100% of the total storage capacity, so MFU-4l, When 80% of hydrogen gas is injected based on 100% of the storage capacity of the liquid hydrogen storage and transportation system including DUT-6 (Zn), MOF-177, MIL-53 (Al), and MOF-74 (Ni). As a result of comparing the desorption temperature of hydrogen liquid, the liquid hydrogen storage and transportation system including DUT-6 (Zn), MOF-177, MFU-4l, MIL-53 (Al), and MOF-74 (Ni) It was confirmed that each desorption temperature starts at 20 K, 24 K, 24 K, 33 K, and 45 K.

That is, in most liquid hydrogen storage and transport systems, the desorption temperature increases by improving the interaction between H2 and the adsorbent by the adsorption energy by including an adsorbent that satisfies a specific maximum diameter and pore volume. In particular, MOF-74 In the case of the storage and transport system of liquid hydrogen containing (Ni), it was confirmed that the adsorbent contained more unsaturated metal binding sites, resulting in more active hydrogen interaction and the highest desorption temperature.

Through this, in the case of a liquid hydrogen storage and transportation system, by satisfying a specific maximum diameter and pore volume of the pores and additionally including an adsorbent containing an unsaturated metal binding site, the desorption temperature is lower than that of the existing liquid hydrogen (LH ₂ ) container and liquid hydrogen. (LH ₂ ) It was confirmed that there was a clear increase compared to the tank.

Experimental Example 4: Comparison of crystal density and volumetric capacity of physisorption-type adsorbents of liquid hydrogen storage and transportation system

As in Example 1, a 1L storage and transport system for liquid hydrogen and an empty storage container without a physical adsorbent were prepared, and then the hydrogen storage capacity for 1L of the empty storage container was checked and compared. Storage and transport of liquid hydrogen The crystal density and volumetric uptake capacity results of the system are shown in Table 1 and Figure 6.

Specifically, Figure 6 is a graph showing the ratio of the volumetric uptake capacity (cryo-adsorbed system) of the storage and transport system for liquid hydrogen compared to the total 100% liquid hydrogen storage capacity for 1L of an empty storage container.

Referring to FIG. 6 and Table 1, the theoretical density of liquid hydrogen (LH ₂ ) is 35.2 mol L ^-1 at 20 K, and based on this, the volume adsorption capacity for the corresponding volume of 1 L of the empty storage container is 35.2 mol L -1 It was confirmed that it was. On this premise, Table 1 shows the volume adsorption capacity results of each liquid hydrogen storage and transport system. Through this, the volumetric adsorption capacity of the storage and transport system of liquid hydrogen varies depending on the crystal density and maximum saturation uptakes of each physisorption-type adsorbent. In particular, the storage of liquid hydrogen It was confirmed that it varies depending on the total volumetric capacity of the transport system.

Accordingly, combining Experimental Examples 1 to 4, the storage and transport system of liquid hydrogen containing DUT-6 (Zn) has the lowest crystal density (0.38g cc ^-1 ) and the highest maximum saturated adsorption amount (88.4mmol). g ^-1 ), and accordingly, its volumetric adsorption capacity is 33.6 mol L ^-1 , which means that the volumetric adsorption capacity of the liquid hydrogen storage and transport system is 100% of the hydrogen storage capacity for 1L of an empty storage container. It was confirmed that it was 96%. However, in the case of the liquid hydrogen storage and transportation system containing DUT-6 (Zn), it was confirmed that the desorption temperature was too small to be suitable as an optimal system.

Meanwhile, storage and transport systems of liquid hydrogen including MIL-53 (Al) and MOF-74 (Ni) have higher 1 bar vaporization temperatures of 135 K and 123 K and relatively high desorption temperatures, respectively, but relatively low volumetric adsorption capacities. could be confirmed.

On the other hand, it can be confirmed that the liquid hydrogen storage and transport system including MOF-177 and MFU-4l has a relatively high volumetric adsorption capacity and a relatively high desorption temperature, showing that it can be used as a relatively optimal system. I was able to confirm.

On the other hand, if an empty storage container contains a physisorption-type adsorbent, the volume of the storage container may be reduced by the volume occupied by the skeleton of the adsorbent. However, for example, in a liquid hydrogen storage and transport system containing DUT-6 (Zn), if DUT-6 has a pore volume of 85%, the framework occupies 15% of the volume, so physically the pore volume is When liquid hydrogen is added to the volume, the capacity is only 85%, but as a result of the experiment, the volumetric adsorption capacity is 88.4mmol g ^-1 at 20K and 1bar, which means that the volumetric adsorption capacity ratio is almost 96%, which means that the volumetric adsorption capacity is approximately 11% higher. You can check that. In other words, as the interaction between the adsorbent and hydrogen becomes greater than the attraction between hydrogen and hydrogen on the skeleton and surface of the physisorption type adsorbent, the adsorbent-hydrogen bond length becomes shorter than the hydrogen-hydrogen bond length near the pore walls of the adsorbent. This is because the hydrogen density becomes higher.

In other words, the optimal storage and transportation system of liquid hydrogen can be derived by determining the volumetric adsorption capacity based on parameters such as crystal density and maximum saturated adsorption capacity, and thus, the optimal storage and transportation of liquid hydrogen. In the case of the system, it can be experimentally confirmed that the volumetric adsorption capacity ratio for liquid hydrogen (LH ₂ ) reaches up to 96% based on 100% of the total storage capacity for liquid hydrogen (LH ₂ ) in the empty storage container. It was confirmed that the storage and transportation competitiveness of liquid hydrogen was superior to existing liquid hydrogen (LH ₂ ) containers and liquid hydrogen (LH ₂ ) tanks. This shows that it can exceed 100% when applying an adsorbent with appropriate pores and volume.

Experimental Example 5: Spectroscopic mechanism analysis of liquid hydrogen storage and transport system

In order to spectroscopically analyze the mechanism of the high maximum saturation adsorption capacity and high desorption temperature of the liquid hydrogen storage and transport system, the liquid hydrogen storage and transport system and an empty storage vessel without physisorption-type adsorbent were placed as in Example 1. The results of the in situ inelastic neutron spectroscopy (INS) experiment are shown in Figures 7a to 7c.

Specifically, Figure 7a is an INS spectrum for para-hydrogen bulk solid and para-hydrogen bulk liquid measured at 10K and 18K, and Figure 7b is a storage and transport system for liquid hydrogen into which different amounts of para-hydrogen were added at 20K. This is the INS spectrum of (DUT-6(Zn)), and Figure 7c is the INS intensity change spectrum according to the amount of para-hydrogen added in Figure 7b.

Referring to Figure 7a, an empty storage container was filled with a sufficient amount of H- ₂ of 46 mmol g ^-1 and the INS spectrum was measured at 10K (below the melting point) and 18K (below the boiling point). As a result, when measured at 10K, it was at 14.6meV. It can be seen that a peak appears, which is due to the rotation transition J:0 1 and serves as a reference for the disordered rotation transition signal for the immobile (in this case solid) H ₂ molecule. In addition, it was confirmed that as the empty storage vessel warms, the effect of recoil becomes more evident and hydrogen mobility increases. At 18K, the rotation transition completely disappears and only the recoil signal remains.

Referring to FIG. 7b, it was confirmed that when an adsorbent is included in the liquid hydrogen storage and transport system (DUT-6(Zn)), the inelastic spectrum of the adsorbed phase is much more complex. Specifically, spectra were investigated at different temperatures (5k-35K) for the liquid hydrogen storage and transport system (DUT-6(Zn)) into which different amounts of para-hydrogen (1.6-51.73mmol g ^-1 ) were added. As a result, it can be seen that several peaks appear in the 11-15 meV range, which indicates that the interaction between the adsorbent surface (quadrupole) and H ₂ molecules hinders the rotation level (J:01), resulting in a lower energy level. It was confirmed that this was due to the presence of various binding sites with different interaction energies.

Also, referring to Figure 7c, as a result of examining the intensity change for the input step of different amounts of para-hydrogen (1.6-51.73 mmol g ^-1 ) into the liquid hydrogen storage and transport system (DUT-6(Zn)), the most It was confirmed that lower energy (~11meV) represents a higher shift from the rotor transition at 14.6meV for higher interaction, confirming the presence of fixed (adsorbed) hydrogen. In particular, adsorbed hydrogen can form shorter bond lengths than bulk-liquid due to the stronger interaction energy between H ₂ and the adsorbent, and the INS peak for immobilized hydrogen is observed up to 35 K, which means that H ₂ It was confirmed that the adsorbed phase remained even after the Tc of ₂ was exceeded. Additionally, because DUT-6 has a very heterogeneous sorption site, it was confirmed that these monolayer loading INS data only partially covered the sorption site.

In other words, in the liquid hydrogen storage and transport system, it was confirmed that the physically adsorbed hydrogen at 20K was tightly and closely adsorbed due to the Van der Waals hydrogen-adsorbent interaction in the adsorbent, and accordingly, It has the advantage of efficiently storing hydrogen through physical adsorption because it enables a shorter adsorbent-hydrogen distance and enables dense packing of hydrogen molecules in the adsorbed stage.

Claims (9)

It includes a physical absorption type adsorbent containing pores, and a storage container containing liquid hydrogen (LH ₂ ),
The physisorption-type adsorbent and liquid hydrogen (LH ₂ ) are physically adsorbed by Van der Waals interaction,
Storage and transportation of liquid hydrogen, characterized in that the volumetric adsorption capacity ratio for liquid hydrogen (LH ₂ ) is 85% to 110% based on 100% of the total volumetric adsorption capacity for liquid hydrogen (LH ₂ ) of the empty storage container. system. According to paragraph 1,
A storage and transport system for liquid hydrogen, wherein the physisorption-type adsorbent further includes an unsaturated metal site. According to paragraph 1,
A storage and transportation system for liquid hydrogen, wherein the maximum diameter of the pores of the physisorption-type adsorbent is 0.5 nm to 20 nm. According to paragraph 1,
The pore volume of the physisorption-type adsorbent is 59 volume % to 96 volume %, based on 100 volume % of the total physisorption-type adsorbent. A storage and transportation system for liquid hydrogen. According to paragraph 1,
A storage and transportation system for liquid hydrogen, wherein the physical adsorption adsorbent has a desorption temperature of 25K or more. According to paragraph 1,
A storage and transport system for liquid hydrogen, wherein the maximum saturation uptake of the physisorption-type adsorbent is 55 mmol/g to 120 mmol/g. According to clause 6,
A storage and transportation system for liquid hydrogen, wherein the input amount of hydrogen gas (H ₂ ) is 80% to 100%, compared to 100% of the total maximum saturated adsorption amount of the physical adsorption type adsorbent. According to paragraph 1,
A storage and transportation system for liquid hydrogen, wherein the crystal density of the physisorption-type adsorbent is 0.20 g/cc to 0.60 g/cc. According to paragraph 1,
A storage and transport system for liquid hydrogen, wherein the volumetric uptake capacity of the physisorption-type adsorbent is 30 mol/L to 40 mol/L.