Classifications

• • F—MECHANICAL ENGINEERING; LIGHTING; HEATING; WEAPONS; BLASTING
  • F17—STORING OR DISTRIBUTING GASES OR LIQUIDS
  • F17C—VESSELS FOR CONTAINING OR STORING COMPRESSED, LIQUEFIED OR SOLIDIFIED GASES; FIXED-CAPACITY GAS-HOLDERS; FILLING VESSELS WITH, OR DISCHARGING FROM VESSELS, COMPRESSED, LIQUEFIED, OR SOLIDIFIED GASES
  • F17C11/00—Use of gas-solvents or gas-sorbents in vessels
  • F17C11/005—Use of gas-solvents or gas-sorbents in vessels for hydrogen
• • F—MECHANICAL ENGINEERING; LIGHTING; HEATING; WEAPONS; BLASTING
  • F28—HEAT EXCHANGE IN GENERAL
  • F28F—DETAILS OF HEAT-EXCHANGE AND HEAT-TRANSFER APPARATUS, OF GENERAL APPLICATION
  • F28F13/00—Arrangements for modifying heat-transfer, e.g. increasing, decreasing
• • F—MECHANICAL ENGINEERING; LIGHTING; HEATING; WEAPONS; BLASTING
  • F17—STORING OR DISTRIBUTING GASES OR LIQUIDS
  • F17C—VESSELS FOR CONTAINING OR STORING COMPRESSED, LIQUEFIED OR SOLIDIFIED GASES; FIXED-CAPACITY GAS-HOLDERS; FILLING VESSELS WITH, OR DISCHARGING FROM VESSELS, COMPRESSED, LIQUEFIED, OR SOLIDIFIED GASES
  • F17C2201/00—Vessel construction, in particular geometry, arrangement or size
  • F17C2201/01—Shape
  • F17C2201/0104—Shape cylindrical
• • F—MECHANICAL ENGINEERING; LIGHTING; HEATING; WEAPONS; BLASTING
  • F17—STORING OR DISTRIBUTING GASES OR LIQUIDS
  • F17C—VESSELS FOR CONTAINING OR STORING COMPRESSED, LIQUEFIED OR SOLIDIFIED GASES; FIXED-CAPACITY GAS-HOLDERS; FILLING VESSELS WITH, OR DISCHARGING FROM VESSELS, COMPRESSED, LIQUEFIED, OR SOLIDIFIED GASES
  • F17C2201/00—Vessel construction, in particular geometry, arrangement or size
  • F17C2201/01—Shape
  • F17C2201/0147—Shape complex
  • F17C2201/0166—Shape complex divided in several chambers
• • F—MECHANICAL ENGINEERING; LIGHTING; HEATING; WEAPONS; BLASTING
  • F17—STORING OR DISTRIBUTING GASES OR LIQUIDS
  • F17C—VESSELS FOR CONTAINING OR STORING COMPRESSED, LIQUEFIED OR SOLIDIFIED GASES; FIXED-CAPACITY GAS-HOLDERS; FILLING VESSELS WITH, OR DISCHARGING FROM VESSELS, COMPRESSED, LIQUEFIED, OR SOLIDIFIED GASES
  • F17C2203/00—Vessel construction, in particular walls or details thereof
  • F17C2203/03—Thermal insulations
  • F17C2203/0304—Thermal insulations by solid means
  • F17C2203/0345—Fibres
  • F17C2203/035—Glass wool
• • F—MECHANICAL ENGINEERING; LIGHTING; HEATING; WEAPONS; BLASTING
  • F17—STORING OR DISTRIBUTING GASES OR LIQUIDS
  • F17C—VESSELS FOR CONTAINING OR STORING COMPRESSED, LIQUEFIED OR SOLIDIFIED GASES; FIXED-CAPACITY GAS-HOLDERS; FILLING VESSELS WITH, OR DISCHARGING FROM VESSELS, COMPRESSED, LIQUEFIED, OR SOLIDIFIED GASES
  • F17C2203/00—Vessel construction, in particular walls or details thereof
  • F17C2203/06—Materials for walls or layers thereof; Properties or structures of walls or their materials
  • F17C2203/0634—Materials for walls or layers thereof
  • F17C2203/0636—Metals
  • F17C2203/0646—Aluminium
• • F—MECHANICAL ENGINEERING; LIGHTING; HEATING; WEAPONS; BLASTING
  • F17—STORING OR DISTRIBUTING GASES OR LIQUIDS
  • F17C—VESSELS FOR CONTAINING OR STORING COMPRESSED, LIQUEFIED OR SOLIDIFIED GASES; FIXED-CAPACITY GAS-HOLDERS; FILLING VESSELS WITH, OR DISCHARGING FROM VESSELS, COMPRESSED, LIQUEFIED, OR SOLIDIFIED GASES
  • F17C2203/00—Vessel construction, in particular walls or details thereof
  • F17C2203/06—Materials for walls or layers thereof; Properties or structures of walls or their materials
  • F17C2203/0634—Materials for walls or layers thereof
  • F17C2203/0636—Metals
  • F17C2203/0648—Alloys or compositions of metals
• • F—MECHANICAL ENGINEERING; LIGHTING; HEATING; WEAPONS; BLASTING
  • F17—STORING OR DISTRIBUTING GASES OR LIQUIDS
  • F17C—VESSELS FOR CONTAINING OR STORING COMPRESSED, LIQUEFIED OR SOLIDIFIED GASES; FIXED-CAPACITY GAS-HOLDERS; FILLING VESSELS WITH, OR DISCHARGING FROM VESSELS, COMPRESSED, LIQUEFIED, OR SOLIDIFIED GASES
  • F17C2221/00—Handled fluid, in particular type of fluid
  • F17C2221/01—Pure fluids
  • F17C2221/012—Hydrogen
• • F—MECHANICAL ENGINEERING; LIGHTING; HEATING; WEAPONS; BLASTING
  • F17—STORING OR DISTRIBUTING GASES OR LIQUIDS
  • F17C—VESSELS FOR CONTAINING OR STORING COMPRESSED, LIQUEFIED OR SOLIDIFIED GASES; FIXED-CAPACITY GAS-HOLDERS; FILLING VESSELS WITH, OR DISCHARGING FROM VESSELS, COMPRESSED, LIQUEFIED, OR SOLIDIFIED GASES
  • F17C2223/00—Handled fluid before transfer, i.e. state of fluid when stored in the vessel or before transfer from the vessel
  • F17C2223/01—Handled fluid before transfer, i.e. state of fluid when stored in the vessel or before transfer from the vessel characterised by the phase
  • F17C2223/0107—Single phase
  • F17C2223/0123—Single phase gaseous, e.g. CNG, GNC
• • F—MECHANICAL ENGINEERING; LIGHTING; HEATING; WEAPONS; BLASTING
  • F17—STORING OR DISTRIBUTING GASES OR LIQUIDS
  • F17C—VESSELS FOR CONTAINING OR STORING COMPRESSED, LIQUEFIED OR SOLIDIFIED GASES; FIXED-CAPACITY GAS-HOLDERS; FILLING VESSELS WITH, OR DISCHARGING FROM VESSELS, COMPRESSED, LIQUEFIED, OR SOLIDIFIED GASES
  • F17C2260/00—Purposes of gas storage and gas handling
  • F17C2260/03—Dealing with losses
  • F17C2260/031—Dealing with losses due to heat transfer
• • F—MECHANICAL ENGINEERING; LIGHTING; HEATING; WEAPONS; BLASTING
  • F28—HEAT EXCHANGE IN GENERAL
  • F28D—HEAT-EXCHANGE APPARATUS, NOT PROVIDED FOR IN ANOTHER SUBCLASS, IN WHICH THE HEAT-EXCHANGE MEDIA DO NOT COME INTO DIRECT CONTACT
  • F28D21/00—Heat-exchange apparatus not covered by any of the groups F28D1/00 - F28D20/00
  • F28D2021/0019—Other heat exchangers for particular applications; Heat exchange systems not otherwise provided for
  • F28D2021/0047—Other heat exchangers for particular applications; Heat exchange systems not otherwise provided for for hydrogen or other compressed gas storage tanks
• • Y—GENERAL TAGGING OF NEW TECHNOLOGICAL DEVELOPMENTS; GENERAL TAGGING OF CROSS-SECTIONAL TECHNOLOGIES SPANNING OVER SEVERAL SECTIONS OF THE IPC; TECHNICAL SUBJECTS COVERED BY FORMER USPC CROSS-REFERENCE ART COLLECTIONS [XRACs] AND DIGESTS
  • Y02—TECHNOLOGIES OR APPLICATIONS FOR MITIGATION OR ADAPTATION AGAINST CLIMATE CHANGE
  • Y02E—REDUCTION OF GREENHOUSE GAS [GHG] EMISSIONS, RELATED TO ENERGY GENERATION, TRANSMISSION OR DISTRIBUTION
  • Y02E60/00—Enabling technologies; Technologies with a potential or indirect contribution to GHG emissions mitigation
  • Y02E60/30—Hydrogen technology
  • Y02E60/32—Hydrogen storage
• • Y—GENERAL TAGGING OF NEW TECHNOLOGICAL DEVELOPMENTS; GENERAL TAGGING OF CROSS-SECTIONAL TECHNOLOGIES SPANNING OVER SEVERAL SECTIONS OF THE IPC; TECHNICAL SUBJECTS COVERED BY FORMER USPC CROSS-REFERENCE ART COLLECTIONS [XRACs] AND DIGESTS
  • Y10—TECHNICAL SUBJECTS COVERED BY FORMER USPC
  • Y10S—TECHNICAL SUBJECTS COVERED BY FORMER USPC CROSS-REFERENCE ART COLLECTIONS [XRACs] AND DIGESTS
  • Y10S420/00—Alloys or metallic compositions
  • Y10S420/90—Hydrogen storage

Definitions

• the present invention relates to hydrogen storage units using hydrideable metal alloys to store hydrogen, and more particularly to a combined heat transfer management/compartmentalization system for use in such systems .
• Hydrogen can be produced from coal, natural gas and other hydrocarbons, or formed by the electrolysis of water. Moreover hydrogen can be produced without the use of fossil fuels, such as by the electrolysis of water using nuclear or solar energy. Furthermore, hydrogen, although presently more expensive than petroleum, is a relatively low cost fuel. Hydrogen has the highest density of energy per unit weight of any chemical fuel and is essentially non-polluting since the main by-product of burning hydrogen is water.
• certain metals and alloys have been known to permit reversible storage and release of hydrogen. In this regard, they have been considered as a superior hydrogen-storage material, due to their high hydrogen-storage efficiency.
• Storage of hydrogen as a solid hydride can provide a greater volumetric storage density than storage as a compressed gas or a liquid in pressure tanks.
• hydrogen storage in a solid hydride presents fewer safety problems than those caused by hydrogen stored in containers as a gas or a liquid.
• Solid-phase metal or alloy system can store large amounts of hydrogen by absorbing hydrogen with a high density and by forming a metal hydride under a specific temperature/pressure or electrochemical conditions, and hydrogen can be released by changing these conditions.
• Metal hydride systems have the advantage of high-density hydrogen-storage for long periods of time, since they are formed by the insertion of hydrogen atoms to the crystal lattice of a metal.
• a desirable hydrogen storage material must have a high storage capacity relative to the weight of the material, a suitable desorption temperature/pressure, good kinetics, good reversibility, resistance to poisoning by contaminants including those present in the hydrogen gas and be of a relatively low cost. If the material fails to possess any one of these characteristics it will not be acceptable for wide scale commercial utilization.
• Good reversibility is needed to enable the hydrogen storage material to be capable of repeated absorption-desorption cycles without significant loss of its hydrogen storage capabilities.
• Good kinetics are necessary to enable hydrogen to be absorbed or desorbed in a relatively short period of time. Resistance to contaminants to which the material may be subjected during manufacturing and utilization is required to prevent a degradation of acceptable performance.
• ceramics may be considered to be generally insulating materials. Therefore, moving heat within such systems or maintaining preferred temperature profiles across and through volumes of such storage materials becomes of interest in metal alloy-metal hydride hydrogen storage systems.
• release of hydrogen from the crystal structure of a metal or metal alloy to become a hydride requires input of some level of energy, normally heat. Placement of hydrogen within the crystal structure of a metal, metal alloy, or other storage system generally releases energy, normally heat, providing a highly exothermic reaction of hydriding.
• the storage material or hydrided material When hydrogen is released, generally on application heat, the storage material or hydrided material will shrink and some particles may collapse.
• the net effect of the cycle of repeated expansion and contraction of the storage material is comminution of the alloy or hydrided alloy particles into successively finer grains. While this process may be generally beneficial to the enhancement of overall surface area of the alloy or storage material surface area, it creates the possibility that the extremely fine particles may sift through the bulk material and settle toward the lower regions of their container and pack more tightly than is desirable. Forming such a high packing density region within a localized area may lead to localized excessive heating upon hydriding or hydrogen charging.
• the same highly packed localized high density region may also produce a great amount of strain on the vessel due to the densification and expansion (upon charging) of the hydrogen storage material .
• the densification and expansion of the hydrogen storage material provide the possibility of deformation or rupture of the container in which the hydrideable material is stored. While pressure relief devices may be useful in preventing such undesired occurrences as the container rupture due to the internal gas pressure of the vessel, pressure relief devices are unable to prevent deformation fo the vessel resulting from densification and expansion of the hydrogen storage alloy. Others have approached the problem by dividing the container into simple compartments in a manner that prevents collection of too many fines in a particular compartment while allowing free flow of hydrogen gas throughout the container.
• the current invention provides for minimization of densification of particulate fines in hydrided or hydrideable materials to prevent the difficulties noted earlier.
• the present invention discloses a hydrogen storage apparatus.
• the hydrogen storage apparatus provides a rechargeable container to store and release hydrogen.
• the container may be a pressure containment vessel with an aluminum or aluminum alloy composition.
• the vessel may be cylindrical in structure and have a restrictive neck.
• a hydrogen storage alloy which stores the hydrogen in a hydride form, is contained inside the vessel .
• a primary partition divides the vessel into multiple compartments.
• a secondary partition further divides the multiple compartments into sub-compartments .
• the primary partition and the secondary partition are also configured to transfer thermal energy between the hydrogen storage alloy and the vessel .
• the compartments are disposed along the longitudinal axis of the vessel.
• the primary partition separating the compartments may be in the form of a disc.
• the primary partition is configured to fit through the restrictive neck of the vessel and spring open once inserted into the vessel.
• the primary partition generally has a metallic composition.
• the metallic composition is preferably a copper/beryllium alloy, but a phosphor/bronze alloy may be substituted when dictated by design constraints.
• the sub-compartments extend longitudinally throughout each of the compartments.
• the sub-compartments also extend from the longitudinal axis of the vessel to the inside wall of the vessel.
• the sub-compartments are at a minimum width at the axis of the vessel and at ' a maximum width at the inside wall of the vessel.
• the secondary partition is made up of multiple rectangular vanes axially connected to one another.
• the rectangular vanes spiral outward to form a pinwheel type orientation about the longitudinal axis.
• the secondary partition is configured to fit through the restrictive neck of the vessel and spring open once inserted into the vessel. When the secondary partition springs open, the multiple rectangular vanes come into thermal contact with the inside wall of the vessel.
• the rectangular vanes tend to have a substantial amount of surface area in contact with the hydrogen storage alloy near the vertical axis of the vessel.
• the rectangular vanes have a metallic composition with good heat transfer properties.
• the rectangular vanes are preferably composed of a copper/beryllium alloy, but a phosphor/bronze alloy may be substituted when dictated by design constraints.
• the compartments and sub-compartments of the present invention prevent densification of the hydrogen storage alloy inside the vessel . Densification and subsequent expansion of the hydrogen storage alloy (upon charging with hydrogen) can cause strain to the wall of the vessel. The expansion of the compacted hydrogen storage material can lead to vessel damage, deformation and rupture.
• the hydrogen storage alloy may be selected from a group including Mg, Mg-Ni, Mg-Cu, Ti-Fe, Ti-Ni, Mm-Co, Ti- Mn, Mm-Ni, and mixtures thereof.
• a preferable alloy is Ti-
• the vessel disclosed in the present invention may have a restrictive neck forming an opening to the vessel.
• a porous fiber material is placed below the restrictive neck to secure placement of said hydrogen storage alloy.
• the porous fiber may also help prevent metal hydride from exiting the vessel with the exiting hydrogen stream.
• the porous fiber is preferably glass wool.
• Figure 1 is a graph showing the flow of hydrogen with respect to time.
• Figure 2 shows a cross-sectional diagram of the present invention.
• FIG 3 shows a diagram of the flapper wheel.
• Figure 4 shows a diagram of the flapper wheel as used in the present invention.
• Figure 5 shows the PCT curves for TA-1, TA-9, TA-10 and TA-11 at 30 °C .
• Figure 6 is a PCT graph of TA-34 at 30 °C and 45 °C.
• Figure 7 is an X-ray diffraction (XRD) analysis of alloy
• Figure 8 is a PCT graph of TA-56 at 30 °C
• Figure 9 is a PCT graph of TA-56D at 30 °C
• This invention applies compartmentalization of the hydride bed within a pressure containment vessel to reduce hydride fines settlement and packing and improve heat transfer from the interior of the hydride bed to the exterior environment. Improvement is made by sub- compartmentalization within the compartments to further minimize the movement of alloy or hydride fines into accumulations sufficient to cause excessive localized stress conditions which may lead to container, generally vessel, damage, deformation, or rupture.
• the sub- compartmentalization may be accomplished in numerous ways with the goal being to segregate smaller volumes of the hydrogen storage alloy thereby limiting the travel, and subsequent settling or accumulation, of the fines which can be expected to be generated within the material through normal use with repetitive charge/discharge cycling.
• This invention includes not only sub- compartmentalization beyond the container compartments, but also employs highly heat conductive materials within the hydride bed for enhancement and management of the heat transfer within the system.
• the low thermal conductivity of the hydrogen storage alloy makes it necessary to enhance the heat transfer through the hydrogen storage alloy. Since heat is added and removed through the outer walls of the vessel, there must also be good thermal contact between the hydrogen storage alloy and the cylindrical wall of the vessel.
• the present invention involves creating sub-compartments within the vessel using materials having good heat-transfer characteristics. In this manner, heat transfer to assist in efficient charging and discharging of hydrogen to and from the storage material and storage bed generally is enhanced and compartmentalization is effectively accomplished.
• This invention preferably employs materials having preferred thermal conductivity as the compartment dividers, generally, the preference will be for dividers of high thermal conductivity but in some circumstances low or variable thermal conductivity across the hydride bed will serve beneficially.
• FIG. 1 compares a vessel without the improved heat transfer (A) to a vessel with improved internal heat transfer (B) .
• the average air temperature surounding the vessels compared in FIG. 1 is in the range of 50-52°C.
• Vessels containing hydrided hydrogen storage alloy are able to provide an improved hydrogen flow rate with the improved internal heat transfer.
• the present invention provides for storage of hydrogen within a preformed cast pressure containment vessel having a restricted neck, however a wide variety of vessels or containers may be used in accordance with the present invention.
• the pressure containment vessel may be cylindrical with a longitudinal axis.
• the vessel may .generally be formed of aluminum and alloys thereof.
• FIG. 2 shows an embodiment of the present invention.
• the hydrogen storage alloy 10 is contained in a plurality of longitudinally positioned compartments 11 inside the pressure containment vessel .
• the compartments are divided into sub-compartments 12, further segregating the volumes of the hydrogen storage alloy 10.
• Discs 13 are used to separate the longitudinally positioned compartments 11.
• the discs 13 are configured to fit through the restricted neck of the vessel and spring open and contact the inside wall of the vessel once inside.
• the discs should be made from a thermally conductive material. The material must not be reactive with the stored hydrogen or the hydrogen storage alloy and be able to withstand the operating temperatures of the system.
• the discs are preferably formed from a beryllium/copper alloy, for optimal heat transfer, but other metals may be substituted such as phosphor/bronze alloys, if cost considerations warrant such a substitution.
• a flapper wheel shaped structure is shown in FIG. 3.
• the flapper wheel 20 comprises a plurality of axially connected rectangular metallic vanes 21 having a pinwheel type orientation about the longitudinal axis 22 of the vessel. By adjusting the length, thickness, and temper of the vanes, the shape of the spiral can be controlled. The vanes 21 can thus be maintained at near constant spacing to avoid any portion of the hydrogen storage alloy 10 from being thermally isolated.
• a cross-sectional view of the flapper wheel as used in the present invention is shown in FIG. 4.
• the flapper wheel 20 is used to divide the compartments 11 into sub-compartments 12. When placed inside the vessel, the vanes form a plurality of longitudinal sub-compartments 12 parallel with the longitudinal axis 22 of the vessel, extending throughout each compartment 11.
• Each sub-compartment 12 is most narrow at the longitudinal axis 22 of the vessel and is widest near the inside wall of the vessel 23.
• the metallic vanes 21 must be long enough, and thin enough to spring back to a shape and size where they make firm contact with the inner wall of the vessel 23 upon insertion, thereby providing good thermal contact with the inner wall of the vessel 23.
• Other reasons for minimizing the thickness of the vanes is to maximize the volume of hydrogen storage alloy within the vessel and reduce the overall cost of the storage unit .
• the flapper wheel 20 provides optimal heat transfer throughout the vessel and prevents compression of the hydride fines within the vessel.
• the flapper wheel 20 is constructed from thermally conductive material to optimize heat transfer throughout the system. The material must also not be reactive with the stored hydrogen or the hydrogen storage alloy and be able to withstand the operating temperatures of the system.
• the flapper wheel 20 is preferably formed from a beryllium/copper alloy composition, for optimal heat transfer, but again, other metals may be substituted such as a phosphor/bronze alloy.
• the pinwheel shape and design of the flapper wheel 20 provide for optimal heat transfer between the metal vanes 21 and the walls of the vessel 23 and between the metal vanes 21 and the hydrogen storage alloy 10. Due to the pinwheel configuration, the metal vanes 21 have a substantial amount of surface area in contact with the hydrogen storage alloy 10, especially near the vertical axis 22 of the storage container. The pinwheel configuration may also provide a substantial amount of surface area in contact with the wall of the vessel 23, when the vanes 21 are in tangential contact with the wall of the vessel 23. Overall, the pinwheel design provides much more surface area as compared to other designs such as metallic bristles extending from the longitudinal axis of the vessel to the interior wall of the vessel. The heat transferred through the flapper wheel 20 provides a near homogeneous temperature throughout the vessel thereby preventing "dead" portions of the hydrogen storage alloy 10 which are so isolated thermally that they are ineffective in absorbing or releasing hydrogen.
• the shape of the flapper wheel 20 allows for easy insertion into cast formed vessels having an opening smaller in diameter than the diameter of the storage vessel .
• the flapper wheel 20 Prior to insertion into the vessel, the flapper wheel 20 is tightly rolled, thereby reducing the diameter of the flapper wheel.
• the flapper wheel is then inserted through the opening of the vessel.
• the flapper wheel springs open and makes firm contact with the inside wall of the vessel 23.
• the hydrogen storage alloy is then inserted into the compartments of the flapper wheel 20 and a disk 13 is placed on top to finalize the formation of a compartment 11. The process is then repeated until the vessel is full.
• glass wool, or another porous fiber may be placed between the vessel opening and the last compartment to prevent any of the hydride fines from exiting the vessel while allowing passage of the hydrogen into and out of the vessel.
• the glass wool or porous fiber also acts to help hold the contents of the vessel in place.
• the hydrogen storage alloy may include a variety of metallic materials for hydrogen-storage, e.g., Mg, Mg-Ni, Mg-Cu, Ti-Fe, Ti-Ni, , Mm-Co, Ti-Mn, and Mm-Ni alloy systems (wherein, Mm is Misch metal, which is a rare-earth metal or combination/alloy of rare-earth metals) .
• metallic materials for hydrogen-storage e.g., Mg, Mg-Ni, Mg-Cu, Ti-Fe, Ti-Ni, , Mm-Co, Ti-Mn, and Mm-Ni alloy systems (wherein, Mm is Misch metal, which is a rare-earth metal or combination/alloy of rare-earth metals) .
• the Mg alloy systems can store relatively large amounts of hydrogen per unit weight of the storage material.
• heat energy must be supplied to release the hydrogen stored in the alloy, because of its low hydrogen dissociation equilibrium pressure at room temperature.
• release of hydrogen can be made, only at a high temperature of over 250 °C along with the consumption of large amounts of energy.
• the rare-earth (Misch metal) alloys have their own problems. Although they typically can efficiently absorb and release hydrogen at room temperature, based on the fact that it has a hydrogen dissociation equilibrium pressure on the order of several atmospheres at room temperature, their hydrogen-storage capacity per unit weight is lower than any other hydrogen-storage material and they are very expensive.
• the Ti-Fe alloy system which has been considered as a typical and superior material of the titanium alloy systems, has the advantages that it is relatively inexpensive and the hydrogen dissociation equilibrium pressure of hydrogen is several atmospheres at room temperature. However, since it requires a high temperature of about 350 °C and a high pressure of over 30 atmospheres for initial hydrogenation, the alloy system provides relatively low hydrogen absorption/desorption rate. Also, it has a hysteresis problem which hinders the complete release of hydrogen stored therein.
• the hydrogen storage alloy for the present invention is preferably a Ti-Mn alloy.
• This alloy has excellent room temperature kinetics and plateau pressures.
• the Ti-Mn alloy system has been reported to have a high hydrogen-storage efficiency and a proper hydrogen dissociation equilibrium pressure, since it has a high affinity for hydrogen and low atomic weight to allow large amounts of hydrogen- storage per unit weight.
• a generic formula for the Ti -Mn alloy is : Ti Q _ x Zr x Mn z , Y A Y , where A is generally one or more of V, Cr , Fe , Ni and Al . Most preferably A is one or more of V, Cr, and Fe .
• the subscript Q is preferably between 0.9 and 1.1, and most preferably Q is 1.0.
• the subscript X is between 0.0 and 0.35, more preferably X is between 0.1 and 0.2, and most preferably X is between 0.1 and 0.15.
• the subscript Y is preferably between 0.3 and 1.8, more preferably Y is between 0.6 and 1.2, and most preferably Y is between 0.6 and 1.0.
• the subscript Z is preferably between 1.8 and 2.1 , and most preferably Z is between 1.8 and 2.0.
• the alloys are generally single phase materials, exhibiting a hexagonal Laves phase crystalline structure. Preferred alloys are shown in Table 1.
• alloys have average storage capacity, ranging from
• Figure 5 is a Pressure-Composition- Temperature (PCT) graph for several of the alloys of the instant invention plotting pressure in Torr on the y-axis versus weight percent of stored hydrogen on the x-axis. Specifically shown are the desorption PCT curves for TA-1, TA- 9, TA-10 and TA-11 at 30 °C.
• Figure 6 is a PCT graph of TA-34 at 30 °C (the ⁇ symbol) and 45 °C (the • symbol) plotting pressure in Torr on the y-axis versus weight percent of stored hydrogen on the x-axis. As can be seen, these alloys have very good plateau pressures at room temperature.
• alloys TA-34, TA-35, TA-56 and TA-56D are lower cost alloys which have reduced V and Cr content and can be made using commercially available ferrovanadium and ferrochromium alloys.
• Figure 7 is an X-ray diffraction (XRD) analysis of alloy TA-34. As can be seen analysis of the XRD plot, the alloys of the instant invention have a hexagonal C 14 Laves phase crystalline structure.
• Figure 8 is a PCT graph of TA-56 at 30 °C (adsorption is solid line, desorption is the dashed line) plotting pressure in Bar on the y-axis versus weight percent of stored hydrogen on the x-axis.
• Figure 9 is a PCT graph of TA-56D at 30 °C (adsorption is the dashed line, desorption is the solid line) plotting pressure in Bar on the y-axis versus weight percent of stored hydrogen on the x-axis. More detailed information regarding the Ti-Mn alloy can be found in commonly assigned copending application Serial No. 09/998,277 filed on November 30, 2001, the disclosure of which is herein incorporated by reference .

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• Engineering & Computer Science (AREA)
• Mechanical Engineering (AREA)
• General Engineering & Computer Science (AREA)
• Physics & Mathematics (AREA)
• Thermal Sciences (AREA)
• Filling Or Discharging Of Gas Storage Vessels (AREA)
• Solid-Sorbent Or Filter-Aiding Compositions (AREA)
• Hydrogen, Water And Hydrids (AREA)

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• 2002
  • 2002-02-21 US US10/080,220 patent/US6626323B2/en not_active Expired - Lifetime
• 2003
  • 2003-02-06 WO PCT/US2003/003861 patent/WO2003072992A1/en not_active Ceased
  • 2003-02-06 EP EP03743121A patent/EP1476693A4/en not_active Withdrawn
  • 2003-02-06 AU AU2003210938A patent/AU2003210938A1/en not_active Abandoned
  • 2003-02-06 JP JP2003571641A patent/JP2005518514A/ja active Pending
  • 2003-02-20 TW TW092103471A patent/TWI278585B/zh not_active IP Right Cessation

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