Patent Application
20230375138
This disclosure relates to a liquefied gas system in which boil-off gas is captured and reversibly stored on an adsorbent to be desorbed for later use. This disclosure further relates to a liquefied gas system in which boil-off gas is captured and reversibly stored on an adsorbent to be desorbed for later use, wherein the system can be adapted for use on a transportation vehicle, with a building, or with industrial equipment.
This disclosure relates to a liquefied gas system in which boil-off gas emitted from a vessel containing a low boiling point gas is captured and reversibly stored on an adsorbent to be desorbed for later use. The system described herein is particularly suitable for use with liquefied hydrogen; however, the use of the system is not limited to liquefied hydrogen, and other liquefied gases can be used in the boil-off capture system as described herein. The system will be described herein with respect to liquefied hydrogen for ease of description and understanding, it being understood that the use of the system is not so limited.
There has been growing interest in the use of renewable energy sources as fuels in the transportation industry and other industrial applications. One area of interest is electric vehicles which use rechargeable battery systems. While battery-based systems can be well suited for smaller vehicles such as passenger cars, they can present significant challenges for larger vehicles or fleets of vehicles, such as freight trucks. The slow recharging rate and low energy density of current lithium battery systems preclude their practical use in heavy-duty vehicles, marine vessels, trains, aircraft, and industrial equipment for farming, mining, and construction. For example, it has been found that a lithium-ion battery-powered truck with 900 miles of range will have a maximum payload of only 4,000 kg, with the gross weight of an empty truck exceeding eight times the payload.
A powertrain that uses a hydrogen fuel cell is an alternative for overcoming the drawbacks of lithium-ion batteries. As the lightest element on the periodic table, hydrogen has the highest gravimetric energy content of all fuels. Therefore, the onboard energy storage based on hydrogen can be significantly lighter than lithium batteries, enabling heavy-duty vehicles to maximize their payload. Further, while charging a lithium battery can take hours, onboard liquid hydrogen tanks can be filled within minutes, minimizing the downtime for the vehicles or equipment, and shortening the payback period. The production of green hydrogen via electrolysis using renewable electricity is being scaled in many countries. Thus, the use of renewable hydrogen is gaining traction across the globe in multiple aspects of our economy, including the transportation and industrial equipment sectors. Hydrogen fuel cells also have been proposed for use in powering buildings, material handling systems, and for providing emergency backup power.
Gaseous hydrogen for use as fuel can be stored in high pressure tanks, but gaseous hydrogen offers low volumetric capacity, even when stored at high pressures. This is problematic for use on vehicles and any other applications in which there are limitations on the size of the hydrogen storage tank. Liquefied hydrogen has a density of about 70 g/l and therefore offers the advantages of high volumetric capacity. Such systems are being developed for use on vehicles such as trucks and ships, and other applications in which there are limitations on the size of the hydrogen storage tank. The use of liquefied hydrogen, however, presents the challenge of boil-off losses. Owing to hydrogen's ultra-low boiling point (20° K), loss of vaporized hydrogen occurs all along the liquid hydrogen supply chain and during any extended storage period.
Accordingly, it is an object of the disclosure to provide a liquefied gas storage system in which boil-off of a liquefied low boiling point gas is captured and stored on an adsorbent to be desorbed for later use.
It is another object of the disclosure to provide a liquid hydrogen system in which boil-off hydrogen is captured and stored on an adsorbent to be desorbed for later use.
It is further an object of the disclosure to provide a liquid hydrogen system that is a fuel system in which boil-off hydrogen is captured and stored on an adsorbent and then desorbed from the adsorbent for use in the system, which system is suitable for use on a transportation vehicle, with a building, or with industrial equipment.
The foregoing objects are met by a liquefied gas system for capturing boil-off gas and reversibly adsorbing the boil-off gas on an adsorbent for later desorption and use, the system comprising
In one embodiment the liquefied gas is liquefied hydrogen, and the system is a liquid hydrogen system for capturing boil-off hydrogen and reversibly adsorbing the boil-off hydrogen on an adsorbent for later desorption and use, the system comprising
Advantageously, the presence of the adsorbent in the adsorbent vessel increases the hydrogen storage capacity of that vessel to capture boil-off hydrogen from the liquid hydrogen storage vessel. As a further advantage, the adsorbent vessel does not need to operate at elevated pressures or at temperatures below the critical temperature of the gas.
In one embodiment the liquid hydrogen system endpoint is a hydrogen fuel-consuming power unit and the liquid hydrogen system provides hydrogen to the hydrogen fuel-consuming power unit. In one embodiment the power unit can be used to operate a transportation unit or an industrial machine. In one embodiment the transportation unit can be selected from a motor vehicle, a train, a marine vessel, or an aircraft; advantageously the liquid hydrogen system as disclosed herein can be used on board the transportation unit. In one embodiment the industrial machine can be selected from a machine used in farming, mining, construction, or manufacturing, and in some embodiments the liquid hydrogen system can be moved as the machine is moved from one location to another.
In one embodiment the liquid hydrogen system is used with a stationary hydrogen fuel system, such as for use in providing power to a building or other stationary structure.
In one embodiment the liquid hydrogen system is a hydrogen refueling system for supplying liquid hydrogen from a liquid hydrogen reservoir to a liquid hydrogen fuel system, and the endpoint of the liquid hydrogen system is the vessel for storing liquid hydrogen in the hydrogen fuel system. Such a refueling system comprises a reservoir for storing liquid hydrogen; a means for transferring liquid hydrogen from the reservoir to the liquid hydrogen storage vessel of a hydrogen fuel system; an adsorbent vessel for adsorbing and storing boil-off hydrogen from the reservoir, the adsorbent vessel containing at least one adsorbent whereby the boil-off hydrogen is reversibly adsorbed on the adsorbent; and a means for desorbing the adsorbed boil-off hydrogen and delivering it either to a liquid hydrogen vessel of a hydrogen fuel system or back to the liquid hydrogen reservoir.
In one embodiment the adsorbent has a pore volume of at least 0.5 cc/g, or at least 1 cc/g. In one embodiment the adsorbent has an adsorption capacity for hydrogen of at least 5 wt % at 60° K and 10 bar. In one embodiment the adsorbent comprises a material selected from one or more of a metal organic framework, a porous activated carbon, a covalent organic framework, a porous organic polymer, a zeolite, and combinations or mixtures of any of the foregoing. When more than one adsorbent is used, the adsorbents can be configured in the adsorbent vessel in radial layers, stacked layers, mixtures, or other configurations.
Also disclosed herein is a method of capturing boil-off gas from a liquefied gas system comprising a liquefied gas storage vessel, the method comprising providing an adsorbent vessel containing an adsorbent that reversibly adsorbs the gas; directing boil-off gas from the liquefied gas storage vessel to the adsorbent vessel; and directing the desorbed boil-off gas from the adsorbent vessel to a system end-point. In one embodiment the liquefied gas is liquid hydrogen.
Disclosed herein is a liquefied gas system for capturing boil-off gas from a source of liquefied gas, wherein the boil-off gas is reversibly adsorbed on an adsorbent for later desorption and use, the system comprising
More specifically, disclosed herein is a liquid hydrogen system for capturing hydrogen boil-off from a liquid hydrogen storage vessel, the system comprising
The liquid hydrogen boil-off capture system can be used in connection with a hydrogen fuel-consuming power system, such as may be used with a transportation unit or hydrogen-powered machinery. The liquid hydrogen boil-off capture system also can be used with a hydrogen refueling system for supplying liquid hydrogen from a reservoir to a hydrogen storage vessel of a hydrogen fuel-consuming power system.
In one embodiment the system captures hydrogen boil-off when the rate of hydrogen boil-off from the liquid hydrogen vessel is greater than the rate of hydrogen delivery from the liquid hydrogen vessel to the system end-point.
In the illustrated embodiments herein the boil-off capture system is used with a hydrogen fuel-consuming power system used to power a transportation unit, such as a freight truck or other heavy-duty motor vehicle. It is to be understood that this embodiment is for illustrative purposes only, and the scope of the disclosure is not necessarily so limited.
Referring to
Liquid hydrogen storage vessel 10 contains liquid hydrogen 12 and a volume of gaseous hydrogen 14 above the top surface of liquid hydrogen 12. Liquid hydrogen storage vessel 10 is provided with insulation 15 to maintain the liquid hydrogen 12 at a temperature below 20° K. Liquid hydrogen storage vessel 10 can be provided with a vaporizer 18 to convert liquid hydrogen 12 to gaseous hydrogen 14 as may be desired to meet the demands of power unit 80. Liquid hydrogen storage vessel includes an opening 11 for release of gaseous hydrogen through conduit 22. Conduit 22 can be fitted with a pressure relief valve 19 sized to release gaseous hydrogen from liquid hydrogen storage vessel 10 in an over-pressuring event.
Liquid hydrogen storage vessel 10 can be filled from a separate liquid hydrogen filling system, not mounted on the transportation unit. The liquid hydrogen filling system can comprise external liquid hydrogen reservoir 13, conduit 16, and control valve 17. In one embodiment (not shown), conduit 16 can be removably connected to opening 11 to fill liquid hydrogen storage vessel 10. In another embodiment as illustrated in
Referring to
Adsorbent storage vessel 40 preferably is located externally of liquid hydrogen storage vessel 10. Adsorbent storage vessel 40 contains a bed 42 of at least one adsorbent capable of adsorbing gaseous hydrogen, as described more fully below. Adsorbent storage vessel 40 is provided with an opening 44 and an opening 46. Preferably, adsorbent storage vessel 40 is maintained at atmospheric pressure or above. Advantageously, maintaining the pressure in adsorbent vessel 40 at above atmospheric pressure will prevent atmospheric oxygen from leaking into the adsorbent vessel. Optionally, the temperature within adsorbent storage vessel 40 can be monitored by temperature indicator 48.
Means 50 for transferring boil-off hydrogen from liquid hydrogen storage vessel 10 to adsorbent storage vessel 40 comprises conduit 52 which extends from juncture 24 to opening 44 of adsorbent storage vessel 40. In one embodiment, means 50 can further comprise valve 54 which controls the flow of boil-off hydrogen through conduit 52.
In addition to insulation 15 around liquid hydrogen storage vessel 10, optionally insulation can be provided around adsorbent storage vessel 40, and the conduits and valves providing inflow and outflow from these vessels. In the illustrated embodiment, liquid hydrogen storage vessel 10 and adsorbent storage vessel 40 are located in sufficiently close proximity to each other such that both vessels can be disposed within the same system of insulation 15 to minimize warming of adsorbent storage vessel 40. Otherwise, two or more separate insulation systems can be provided for liquid hydrogen storage vessel 10 and adsorbent vessel 40, depending on the configuration of these components in liquid hydrogen system 1.
Means 60 for delivering desorbed boil-off hydrogen from adsorbent storage vessel 40 to power unit 80 comprises conduit 62 which extends from conduit 44 to conduit 26. In one embodiment, means 60 further comprises valve 64 and check valve 66 such that desorbed hydrogen gas flows through conduit 62, valve 64 and check valve 66 from which conduit 62 joins conduit 26 leading ultimately to power unit 80.
When adsorbent bed 42 in adsorbent vessel 40 is saturated with boil-off hydrogen from liquid hydrogen storage vessel 10, the bed can be regenerated by desorbing the hydrogen adsorbed therein. In one embodiment, hydrogen can be desorbed from bed 42 and drawn through opening 44 by applying a negative pressure at opening 44 by means such as a pump, not shown. The desorbed hydrogen can then be directed through means 60 to be delivered to power unit 80.
Optional regenerant system 90 for regenerating adsorbent bed 42 comprises conduit 92 which leads from juncture 24; flow control valve 94; regenerant heater 95, the temperature of which is controlled by temperature controller 96; and regenerant pressure regulator 97. In some embodiments check valve 99 and back pressure regulator 98 also can be included in regenerant system 90. Hydrogen from regenerant heater 95 is directed into opening 46 of adsorbent storage vessel 40. Pressure of the adsorbent storage vessel 40 is maintained at below a desired level by back pressure regulator 98; in one embodiment the back pressure regulator 98 will vent hydrogen when the pressure within adsorbent storage vessel 40 exceeds 10 bar.
It will be understood that the various features of the different embodiments as disclosed herein can be used in any combination. For example, it is within the concept of the disclosure to provide a hydrogen boil-off capture system that has an adsorber bed with no cooling, or with external cooling as illustrated in
In the illustrated embodiment the system is portable and end point 80 is a power unit that consumes hydrogen to generate power such as for a hydrogen powered freight truck. The disclosed system can be used anywhere a mobile liquid hydrogen system is used. The liquid hydrogen system with hydrogen boil-off capture as disclosed herein can be used on any means of transportation such as a motor vehicle, a train, a water craft, and an aircraft, and the boil-off capture system is on board the means of transportation along with the associated power unit. In one embodiment the liquid hydrogen system can be used to power an industrial machine, such as a machine used in farming, mining, construction, or manufacturing, and in some embodiments the liquid hydrogen system can be moved as the machine is moved from one location to another. It will be appreciated, however, that in alternative embodiments the power unit 80 can be a power unit of a stationary liquid hydrogen fuel system such as may be used to provide power to a building or other stationary structure. In other embodiments, the system is not part of a power generating system but is instead part of a liquid hydrogen transfer system. Then end point 80 is not a power unit but is connected to a liquid hydrogen storage vessel such as for use with a power-generating system.
The adsorbent which can be used comprises any number of adsorbents which are characterized by a B.E.T. surface area of at least 200 m2/g or at least 400 m2/g or at least 600 m2/g, or at least 1000 m2/g or at least 5000 m2/g, or at least 8000 m2/g or at least 10,000 m2/g. In a particular aspect, the surface area is from about 200 m2/g to about 10,000 m2/g. Also suitable are those adsorbents having a pore volume of at least 0.5 cc/g, or at least 1 cc/g. In one embodiment the adsorbent has an adsorption capacity for hydrogen of 5 wt % at 60° K and 10 bar. General categories of adsorbents which have this property and can be used in the invention include without limitation metal organic framework materials (MOFs), zeolites, activated carbon, covalent organic frameworks (COFs), porous organic polymers (POPs) and mixtures thereof.
MOFs are well known porous adsorbents with high surface areas. MOF adsorbents comprise metal ion corner atoms and an at least bidentate linker molecule or a ligand, which is connected to the corner atom(s) thereby forming a framework structure. The metal ions which can be used include but are not limited to Li+, Na+, K+, Rb+, Be2+, Mg2+, Ca2+, Sr2+, Ba2+, Sc3+, Y3+, Ti4+, Zr4+, Hf4+, V5+, V4+, V3+, Nb3+, Ta3+, Cr3+, Cr2+, Mo3+, W3+, Mn3+, Fe3+, Fe2+, Ru3+, Ru2+, Os3+, Os2+, Co3+, Co2+, Ni2+, Ni+, pd2+, pd+, pt2+, Pt+, Cu2+, Cu+, Ag+, Au+, Zn2+, Al3+, Ga3+, In3+, Si4+, Si2+, Ge4+, Ge2+, Sn4+, Sn2+, Bi5+, Bi3+, Cd2+, Mn2+, Tb3+, Gd3+, Ce3+, La3+, Cr4+, and mixtures thereof. A subgroup of the metal ions is selected from Ti4+, Zr4+, Hf4+, Fe3+, Fe2+, Co3+, Co2+, Ni2+, Ni+, Cu2+, Cu+, Zn2+, Ga3+, Al3+ and mixtures thereof. From this subgroup one subgroup of metal ions includes those selected from Ti4+, Zr4+, Fe3+, Co3+, Ni2+, Cu2+, Zn2+, Ga3+, Al3+ and mixtures thereof. Another subgroup of metal ions includes Fe3+, Cu2+, and Zn2+. Another subgroup of metal ions includes Ca2+, Cu2+, Zn2+, Fe3+, Fe2+, and Y3+. In one embodiment the metal ion is Ca2+; in one embodiment the metal ion is Cu2+; in one embodiment the metal ion is Zn2+; in one embodiment the metal ion is Fe3+; in one embodiment the metal ion is Fe2+; in one embodiment the metal ion is Y3+.
The metal ion corner atoms are joined by at least bidentate organic linker molecules comprising two or more sites capable of binding to a metal ion corner atom to form a metal organic framework structure. Optionally, at least bidentate inorganic linker molecules also can be used. The at least bidentate organic linker molecules include but are not limited to those having a saturated or unsaturated alkyl or aryl backbone, optionally comprising one or more heteroatoms S, N, O, or P, and optionally comprising one or more functional groups bonded to the backbone. In certain embodiments the linker backbone can comprise one or more groups selected from 1) saturated or unsaturated, linear, branched or cyclic alkyl groups having from 1 to 10 carbon atoms and optionally comprising heteroatoms; and 2) groups comprising 1 to 5 aryl or heteroaryl rings which can be fused or joined covalently; wherein the hetero atoms are selected from S, N, O, P and mixtures thereof. The backbones of the linker molecules may have bonded thereto one or more functional groups, including but not limited to saturated and unsaturated alkyl, aryl, heteroaryl, halide, —OH, —NH2, —COOH, NO2, COH, CO(NH2), CN and thiols. In one embodiment the functional groups are selected from COOH and NH2.
Silicon halides such as SiF6 also may be used as linkers in the framework structure.
A subgroup of these ligands includes substituted or unsubstituted, mono- or polynuclear aromatic di-, tri- and tetracarboxylic acids and unsubstituted or substituted, with at least one hetero atom, aromatic di-, tri- and tetracarboxylic acids. In one embodiment the ligands include without limitation 1,3,5-benzene tricarboxylic acid (BTC), triazine tris-benzoic acid (TATB), 2-amino-terephthalic acid, naphthalene dicarboxylate (NDC), acetylene dicarboxylate (ADC), benzene-1,4-dicarboxylic acid (BDC), benzene tribenzoate (BTB), methane tetrabenzoate (MTB), adamantane tetracarboxylate (ATC), adamantane tribenzoate (ATB), 4,4′,4″,4″′-(pyrene-1,3,6,8-tetrayl)tetrabenzoic acid (TBAPy), meso-Tetraphenylporphine-4,4′,4″,4″′-tetracarboxylic acid (TCPPH2), 3,3′,5,5′-azobenzenetetracarboxylic acid, 2,5-dihydroxyterephthalic acid, pyrazine, 1,4-diazabicyclo[2.2.2]octane, SiF6, a ligand of the formula
which is 5,5′,5″-(4,4′,4″-(benzene-1,3,5-triyl)tris(1H-1,2,3-triazole-4,1-diyl))triisophthalic acid, and mixtures thereof. In one embodiment the ligands include without limitation terephthalic acid, azobenzene tetracarboxylic acid, trimesic acid, 1,4-diazabicyclo[2.2.2]octane, and the ligand of formula
and mixtures thereof. Other ligands that can be used include 4,4′-sulfonyldibenzoic acid, 1H,5H -benzo(1,2-d:4,5-d′)bistriazole, 7,7′,8,8′-tetracyanoquinodimethane, squaric acid, and azobenzene-4,4′-dicarboxylic acid.
Specific MOFs include without limitation MOF-5 which a MOF comprising Zn2+ and terephthalic acid; MIL-101 which is MOF comprising Fe3+ and terephthalic acid; NU-125 which is a MOF comprising Cu2+ and the ligand of formula
PCN-250, which is a MOF comprising Fe3+ and azobenzene tetracarboxylic acid; HKUST-1, which is a MOF comprising Cu2+ and trimesic acid; MOF-177 which is a MOF comprising Zn2+ and the ligand benzene tribenzoate (BTB); Zn2(BDC)2(DABCO) which is a MOF comprising Zn2+, terephthalic acid, and 1,4-diazabicyclo[2.2.2]octane; SBMOF-1 which is a MOF comprising Ca2+ and 4,4′-sulfonyldibenzoic acid, MFU which is a MOF comprising Zn2+ and 1H,5H -benzo(1,2-d:4,5-d′)bistriazole; Cu(TCNQ) which is a MOF comprising Cu2+ and 7,7′,8,8′-tetracyanoquinodimethane; CaSquarate which is a MOF comprising Ca2+ and squaric acid; and Y-ABTC which is a MOF comprising Y3+ and azobenzene-4,4′-dicarboxylic acid; and mixtures thereof.
There are several ways to prepare MOF compositions but the most commonly used one is the solvothermal synthesis. For example, see Yujia Sun and Hong-Cai Zhou, Recent Progress in the Synthesis of Metal Organic Frameworks, Sci. Technol. Adv. Mater. 16 (2015), 054202 which is incorporated by reference. In this procedure a metal salt and the desired ligand/linker are dissolved in an appropriate solvent and reacted at an elevated temperature for a required time. Once the MOF is formed, the powder is isolated from the reaction mixture, washed, and dried.
Another adsorbent which can be used in the process of the invention is a zeolite. Zeolites are crystalline aluminosilicate compositions that are microporous and that are formed from corner sharing AlO2 and SiO2 tetrahedra. Numerous zeolites, both naturally occurring and synthetically prepared, can be used in the practice of the invention. Synthetic zeolites are prepared via hydrothermal synthesis employing suitable sources of Si, Al, and structure directing agents such as alkali metals, alkaline earth metals, amines, and/or organoammonium cations. The structure-directing agents reside in the pores of the zeolite and are largely responsible for the particular structure that is ultimately formed. These species balance the framework charge associated with aluminum and can also serve as space fillers. The naturally occurring zeolites include but are not limited to faujasite, analcime, chabazite, clinoptilolite, heulandite, natrolite, phillipsite, stilbite, mordenite, erionite, offretite, ferrierite and mixtures thereof. Of these, faujasite, chabazite, clinoptilolite, phillipsite, mordenite, erionite, offretite, ferrierite and mixtures thereof are of particular interest. Synthetic zeolites include without limitation zeolites A, B, X, Y, L, alpha, beta, omega, ZSM-5, silicalite, ZSM-11, MCM-22, ZK-4, EU-1, FU-1, NU-1, LZ-210 and mixtures thereof. Part or all of the silica in a zeolite can be substituted. For example, SAPO, ALPO, MeAPO, where Me is a metal selected from Li, Be, B, Mg, Mn, Si, Ti, Fe, Zn, Ga, Ge, As, and Cr. A review of the history of zeolites along with their structures and characteristics can be found in Studies in Surface Science and Catalysis, vol. 137, H. van Bekkum, E. M. Flanigen, P. A. Jacobs and J. C. Jansen (editors), 2001, Elsevier Science B.V. which is incorporated by reference.
Another adsorbent that can be used in the system is activated carbon. Activated carbon is a highly porous, high surface area adsorptive material with a largely amorphous structure. It is composed primarily of aromatic configurations of carbon atoms joined by random cross- linkages. The degree of order varies based on the starting raw material and thermal history. Graphitic platelets in steam-activated coal are somewhat ordered, while more amorphous aromatic structures are found in chemically activated wood. Randomized bonding creates a highly porous structure with numerous cracks, crevices and voids between the carbon layers. Activated carbon sorbents are tailored for specific applications mainly based on pore size and pore volume requirements. Porosity and other parameters are controlled by the following: 1) raw material selection; 2) activation process conditions; and 3) post-processing steps. Depending on the application, activated carbon may be in the form of powder (PAC), granule (GAC) or extrudate (EAC). All three forms are available in a range of particle sizes. A review of the fundamentals of activated carbon can be found in an article entitled: Activated Carbon: Fundamentals and New Applications, Ken Koehlert, Chemical Engineering, July 2017, pp. 32-40, which is incorporated by reference. One brand of activated carbon that may be suitable in the disclosed system is Maxsorb® high surface area activated carbon.
Porous organic polymers (POP) are the polymerization product from at least a plurality of organic monomers. POPs are generally constructed from monomer units that are multitopic (three or more connection points). While the degree of cross-linking in a microporous polymeric material depends on the concentration of cross-linking molecules added, cross-linking in POPs is dictated by the valency/topicity of the monomer or co-monomer unit(s). Cross-links in POPs, formed between rigid building blocks, are also different from those in polymer gels, which are usually formed between flexible chains and side chains. POPs are amorphous materials and their synthesis is well known in the art. For example, POPs can be synthesized from the reaction of: 1) catechol and aryl halides; 2) anhydride monomer and diamine monomer; and 3) carboxylic monomer and diamine monomer.
Covalent organic frameworks (COF) are a subset of POPs in that they are crystalline materials. Again, these materials and their synthesis are well known in the art.
Regardless of which type of adsorbent or combination of adsorbents is chosen, it is necessary that the adsorbent have pores from about 2 to about 500 angstroms, or from about 3 to about 500 angstroms, or from about 3 to about 200 angstroms, or from about 3 to about 100 angstroms, or from about 5 to about 200 angstroms, or from about 10 to about 200 angstroms, or from about 5 to about 100 angstroms or from about 10 to about 100 angstroms. Smaller pores increase the interaction between the adsorbents and the hydrogen molecules, thus facilitating the adsorption-based capture.
Although the various adsorbents can be used in the powder form, it may be advantageous to form the adsorbent into various shaped bodies such as pellets, spheres, disks, monolithic bodies, irregularly shaped particles and extrudates. The methods of forming these types of shapes are well known in the art. The adsorbent materials can be formed into various shapes by themselves or by including a binder. When selecting a binder, it is important to select a binder such that the surface area and adsorption capacity is not adversely affected once the desired shaped body is formed. Materials which can be used as binders include without limitation cellulose, silica, carbon, alumina, and mixtures thereof.
The forming process usually involves preparing a thick paste-like material by mixing the adsorbent composition with a solvent or a binder plus a solvent. Once the paste-like material is formed it can be extruded through a die having holes of about 1-2 mm to form extrudates of varying length, e.g. 6-10 mm. The paste or even the powder itself can be pressed at high pressure to form pellets or pills. Other means of forming shapes include pressure molding, metal forming, pelletizing, granulation, extrusion, rolling methods and marumerizing.
In yet another aspect of the invention, the adsorbent materials can be deposited onto articles such as, but not limited to, monoliths, spherical supports, ceramic foams, glass fibers, woven fabrics, nonwoven fabrics, membranes, pellets, extrudates, irregularly shaped particles, and mixtures thereof. When the desired article is a monolith, spherical support, ceramic foam, pellets, extrudates, or irregularly shaped particles, a slurry of the adsorbent composition is prepared and deposited on the article by means such as dipping, spray drying, etc. followed by drying and optionally calcination.
It is also within the scope of the invention that more than one type of adsorbent can be used to reversibly adsorb the hydrogen in the adsorbent bed. For example, two or more adsorbents can be mixed and formed into a bed. Alternatively, the adsorbents can be used as separate layers in a bed. In the case where the adsorbents are deposited onto fabrics, such as woven or non-woven fabrics, the adsorbents can be mixed and deposited as a mixture or deposited as separate layers on one fabric or deposited on separate fabrics and layered. If the adsorbents are formed into shapes such as pellets, spheres, extrudates, again two or more adsorbent powders can be combined and formed into such shapes. Alternatively, each adsorbent can be formed into a desired solid shaped article and then arranged in separate layers or the solid shaped articles mixed and then arranged in a bed or other configuration.
Also disclosed herein is a method of capturing boil-off hydrogen from a liquid hydrogen system, the method comprising providing a liquid hydrogen storage vessel; providing an adsorbent vessel containing an adsorbent that reversibly adsorbs gaseous hydrogen; directing boil-off hydrogen from the liquid hydrogen storage vessel to the adsorbent vessel; and directing the adsorbed boil-off hydrogen from the adsorbent vessel to a system end-point, substantially as illustrated herein.
In yet another embodiment the liquefied gas boil-off system is used with a gas other than hydrogen. For example, the boil-off system as disclosed herein can be used to capture boil-off gas from stored liquefied low-boiling gases, particularly the rare or noble gases such as argon (b.p. 87.3° K), xenon (b.p. 165° K), krypton (b.p. 119.7° K), neon (b.p. 27.1° K) and helium (b.p. 4° K). The adsorbed gas can be desorbed when desired and either returned to the liquefied gas storage vessel or directed to another system end point such as one to which gas from the liquefed gas storage vessel is directed. When the liquefied gas is either xenon or krypton, a suitable adsorbent can include SBMOF-1. When the liquefied gas is neon, a suitable adsorbent can include any one or more of MFU-4, Cu(TCNQ) CaSquarate, and Y-ABTC.
The foregoing description of embodiments of the liquefied gas boil-off capture system are presented by way of illustration and not by way of limitation. Those skilled in the art will recognize that many variations are possible within the spirit and scope of the disclosure, which is intended to be defined by the following claims and their equivalents in which all terms are meant in their broadest reasonable sense unless otherwise indicated.
This application claims priority from U.S. Provisional Application No. 63/444,447, filed May 20, 2022 which is incorporated herein in its entirety.
This invention was made with U.S. Government support under Agreement No. DE-SC0021910 awarded by the Department of Energy. The Government has certain rights in the invention.
| Number | Date | Country | |
|---|---|---|---|
| 63344447 | May 2022 | US |
