Showing papers on "Hydrogen storage published in 1978"

Use of carbon dioxide in energy storage

Abstract: We have investigated an energy‐storage cycle in which CO2 is electrochemically reduced to formic acid, HCOOH. The product can be used in several ways. By means of a catalyst, it can be converted to hydrgen for use as a fuel or raw material. We have obtained data on the efficiency of the process and analyzed the energetics.

Hydrogen supply method

Abstract: A system for supplying hydrogen to an apparatus which utilizes hydrogen, contains a metal hydride hydrogen supply component and a microcavity hydrogen storage hydrogen supply component which in tandem supply hydrogen for the apparatus. The metal hydride hydrogen supply component includes a first storage tank filled with a composition which is capable of forming a metal hydride of such a nature that the hydride will release hydrogen when heated but will absorb hydrogen when cooled. This first storage tank is equipped with a heat exchanger for both adding heat to and extracting heat from the composition to regulate the absorption/deabsorption of hydrogen from the composition. The microcavity hydrogen storage hydrogen supply component includes a second tank containing the microcavity hydrogen supply. The microcavity hydrogen storage contains hydrogen held under high pressure within individual microcavities. The hydrogen is released from the microcavities by heating the cavities. This heating is accomplished by including within the tank for the microcavity hydrogen storage a heating element.

Hydrogen storage material

Abstract: An economical metallic material for storage of hydrogen comprising an alloy representable by the formula ABα in which "A" comprises from 50 to under 100 atomic percent of titanium and the remainder which is at least one element selected from the group I consisting of zirconium and hafnium, B comprises from 30 to below 100 atomic percent of manganese and the remainder which is at least one element selected from the group II consisting of chromium, vanadium, niobium, tantalum, molybdenum, iron, cobalt, nickel, copper and rare earth elements, and α is a value indicating a ratio of B to A, and is in the range of 1.0 to 3.0. The materials of the invention very easily absorb large amounts of hydrogen and efficiently release it at other predetermined temperatures, pressures and electrochemical conditions, whereby it is able to store hydrogen safely, usefully and economically.

The formation of metastable hydrides Ti0.75Al0.25Hx with x < 1.5

Abstract: Ternary hydrides Ti 0.75 Al 0.25 H x were formed at temperatures below 200 °C by absorption from hydrogen gas. The hydriding was studied by means of volumetric analysis and X-ray diffraction. Phases were identified as α(h.c.p.) for x x x 2 formation. The pressure of the β + γ plateau is given as JRTlnP H 2 = ΔH − TΔS with ΔH = −11.3 kcal and AS = −30.4 cal K −1 . The β + γ plateau pressure was 1 atm at 100 °C which approaches a useful range for hydrogen storage applications. The alloy has an attractive hydrogen-to-metal ratio of about 1.5, but the γ phase formed irreversibly. The attainment of reversibility in the γ phase formation is the dominant problem in developing useful Ti-Al-H alloys for hydrogen storage.

Hydrogen in metals

Abstract: Research on interstitial alloys of hydrogen with metals began over a hundred years ago, but these systems had remained little more than idle curiosities until World War II. This outlook changed when hydrogen embrittlement became recognized as a serious problem in a large number of technologically important alloys and with the advent of nuclear‐reactor technology, which stimulated interest in solid metal hydrides as moderators. Several studies of the thermodynamics of metal–hydrogen systems and of hydrogen diffusion in these systems followed. The discovery in 1972 that some metal hydrides exhibit superconductivity added further interest.

Hydrides of LaNi and CeNi intermetallic compounds

Abstract: The hydriding characteristics of La7Ni3, LaNi and Ce7Ni3 have been investigated. These compounds form the stable hydrides La7Ni3H19.3, LaNiH3.85 and Ce7Ni3H19.2. In structural and magnetic investigations La7Ni3is found to decompose into LaH3 and LaNi5 on rapid hydrogenation. On desorption at elevated temperatures the original La7Ni3 structure is reformed. An analogous decomposition is found in Ce7Ni3. The enthalpies of formation ΔH have been measured calorimetrically for the hydrides of LaNi compounds. ΔH varies linearly with the LaNi composition, independently of the various compound structures and of structural transformations on hydrogenation. The experimental values of ΔH are described by a phenomenological model. Despite their high hydrogen content, these hydrides are not suitable for use as hydrogen storage materials because of their high stability.

Hydrogen fuel systems

Abstract: A hydrogen fuel system for use in conjunction with and as an alternative to a hydrocarbon fuel system in a motor vehicle or other apparatus having a combustion unit and a mixing device for mixing hydrogen gas with air for introduction into the combustion unit. The hydrogen fuel system includes a hydrogen storage tank for holding hydrogen under pressure, a conduit for conveying hydrogen gas from the tank to the mixing unit, and a solenoid disposed in the conduit and responsive to a first signal for allowing the flow of hydrogen gas to the mixing unit, and responsive to a second signal for preventing flow of hydrogen gas to the mixing unit. Also included is a hydrocarbon fuel tank, a conduit for conveying fuel from the fuel tank to the combustion unit, and a fuel pump responsive to the first signal for preventing flow of fuel from the fuel tank to the combustion unit, and responsive to the second signal for pumping fuel to the combustion unit. A two-position, manually operable switch is provided to produce the first signal when in a first setting and the second signal when in a second setting.

Synthesis and properties of useful metal hydrides. A review of recent work at Brookhaven National Laboratory

Abstract: Publisher Summary This chapter discusses the synthesis and properties of useful metal hydrides. The properties of intermetallic hydrides have found to be of interest for convenient and economic storage of hydrogen. It is rather difficult to predict a priori whether an intermetallic compound will react with hydrogen or as to which reaction path will be followed and what products will form. However, some empirical predictive theories have been developed, of which the most notable is the theory of reversed stability. This theory has been quite useful in systems involving AB5 alloys, but it has enjoyed only limited success in those involving first row transition intermetallic compounds. It is found, however, that intermetallic-hydrogen systems, without exception, will obey three rather simple rules: (1) in order for an intermetallic compound to react directly and reversibly with hydrogen to form a distinct hydride phase, it is necessary that at least one of the metal components be capable of reacting directly and reversibly with hydrogen to form a stable binary hydride, (2) if a reaction takes place at a temperature at which the metal atoms are mobile, the system will assume its most favored thermodynamic configuration, and (3) if the metal atoms are not mobile, only hydride phases can result that are structurally very similar to the starting intermetallic compound.

The metallurgy and production of rechargeable hydrides

Abstract: The hydrogen storage properties of metal alloy hydrides are intimately related to the metallurgy and microstructures of those alloys. The understanding of the metallurgy then becomes an important consideration in the practical production of a given alloy for hydrogen storage applications. Using FeTi and nickel-mischmetal-calcium as representatives of AB and AB5 compounds, respectively, interrelations among composition, alloy microstructure, and hydrogen storage properties are presented in relation to large scale melting considerations.

Hydrogen storage module

Abstract: Discloses a hydrogen storage module comprising a fluted tube section closed at each end with a gas permeable porous plug and containing a metal adapted to form a hydride or the hydride of such metal.

Hydrogen charged alloys of Zr(A1-x Bx)2 and method of hydrogen storage

Abstract: Hydrogen containing alloys of the formula Zr(A1-x Bx)2 are disclosed in which A designates V, Mn or Cr, B designates Fe or Co, and x is between 0.05 and 0.9. Storage systems for hydrogen comprising such an alloy are also disclosed as well as a method for the controlled storage and release of hydrogen which comprises charging such an alloy with hydrogen and releasing the hydrogen at a desired predetermined rate by heating it to a certain predetermined temperature.

Combined hydrogen storage and production process

Abstract: In a combined process for the storage and production of hydrogen from a hydrogen reserve containing magnesium in the free or combined state, said process consisting of storing the hydrogen in the supply, decomposing the supply to produce hydrogen, and reconstituting the supply of hydrogenation; the use of a dope comprising two elements in the free or combined state selected from the group consisting of cerium, nickel, titanium and molybdenum. Said process may be applied to hydrogen reserves used to fuel internal-combustion engines and for similar applications.

Mechanism for the isothermal decomposition of iron titanium hydride

Abstract: The kinetics of the isothermal decomposition of iron titanium hydride are described in a model in which the diffusion of hydrogen out of the hydride is rate determining. The model produces a diffusion constant which is in good agreement with that found by NMR methods. The mechanism of decomposition in this system is a result of the rapid diffusion of hydrogen in the solid lattice. Consequently, this mode of decomposition is probably unique to metal hydrides; however, not every metal hydride will decompose in this manner.

The storage and release of hydrogen from magnesium alloy hydrides for vehicular applications

Abstract: The optimum hydride for “on-board” vehicular storage of hydrogen depends upon numerous parameters, such as rapid discharge kinetics at a temperature low enough to use exhaust-gas waste heat (about 220-250°C), a high hydrogen density (to minimize the “carrier” weight), and resistance to fragmentation. Magnesium alloys exhibit some outstanding features but are deficient in other characteristics. The research program involved the study of numerous alloying additions, single-phase versus two-phase alloys, and binary versus ternary alloys in order to find the optimum alloy for hydrogen storage. Dilute solid solutions of Mg with 1 a/o Ag, Al, Cd, In, Pb, Y, and Zn were hydrided (−25 + 42 mesh chips) at 400°C to 800 psi H2. Alloys containing Ag, Al, In, and Y exhibited the most rapid hydriding kinetics, ∼5-6 w/o in 24 hours (7.6 w/o theoretical for 100% MgH2). Dehydriding at 300 and 330°C was most rapid for Mg-1Y, followed in order by Mg-1Al, Mg-1Ag, and Mg-1In. Only the Mg-1Y alloy appeared promising at 300°C. Two-phase, binary and ternary alloys were investigated. Mg-5 a/oY was subjected to numerous hydriding and dehydriding cycles in a closed system and was found to release about 3% hydrogen in six hours at 270°C. The best alloy studied was the ternary Mg-5Ni-5Y which released over 3% hydrogen in 4 hours at 250°C. This alloy came the closest to fulfilling the program objectives and is a viable storage medium for vehicular applications. Mechanistic studies were performed on both slabs and chips. Hydriding of single-phase alloys and those with small amount of second phase resulted in very rapid nucleation of hydrides internally. The hydrides grew as spheres within the alloy suggesting that hydrogen diffusion was extremely rapid and the rate-controlling step was the interface movement of the hydride as it consumed the alloy. Alloys containing large amounts of second phase hydrided preferentially in the primary magnesium, the hydrides growing as a front both from the edges and within the interior. Dehydriding of solid-solution alloys or those containing a small volume fraction of second phase, e.g., Mg-5Y, had high activation energies, on the order of 28 kcal/mol, which suggests that the rate-controlling step was the interface movement of the reformed magnesium as it advanced into and consumed the hydride. The Mg-5Ni-5Y alloy has an activation energy of 13.1 kcal/mol which is attributed to mixed kinetics involving both interfacial migration and hydrogen diffusion.

Hydrogen storage technology for metal hydrides

Abstract: The advantages of using hydrogen as a secondary energy carrier are stated, and numerous factors pertinent to the technology of hydrogen storage via metal hydrides are briefly described. The technology is centered on iron-titanium hydride, FeTiH/sub x/, as the most practical choice for the safe and compact storage of hydrogen. Uses of hydride hydrogen as a fuel or energy carrier are given. The features of hydride reservoir designs are explained, and some performance data are given for two reservoirs constructed at BNL. Results of tests on the long-term behavior of FeTiH/sub x/ are presented along with information on pressure drop in a hydride bed. Two methods of accommodating hydride expansion are described. Other topics include: container materials selection, safety testing of FeTiH/sub x/, hydride materials development, storage systems work at BNL, the proposed Hydrogen-Halogen Energy Storage System, a proposed technique of storing hydrogen in hollow glass microspheres at very high pressure, and information on the commercial availability of materials and equipment for hydride hydrogen. Current development needs are included in the various sections.

Solubility Isotherms of Tritium in Palladium at Low Equilibrium Pressures

Abstract: The phenomenon of hydrogen absorption by metals, discovered about 100 years ago, nowadays demands some interest for technological reasons (hydrogen storage, fuel cells, hydrogen embrittle­ ment of construction materials). The palladium/hydrogen system claims for an exceptional position among the metal hydrides of the protonic type: because of its relative simplicity the Pd/H2-system serves as a model revealing some discernible thermodynamic features, that govern the behaviour of those systems. From measurements of Nernst [1] and Frieske [2] the systems Pd/U2 and Pd/U2 are well known, whereas the Pd/T2-system is widely unknown; from separation factor measurements with traces of tritium [3] in the hydrogen-rich /5-phase of the Pd-hydride one can calculate the /?-PdTn isotherms [4]. Direct measurements on the PdTn-system (n = T/Pd) at low tritium pressures were performed by Favreau et al. [5] (temperature region 200 to 400 °C); the results of this research, however, are not in agreement with what can be extrapolated from the PdHnand PdDn-systems, assuming a normal run of the isotope effect. For this reason and since, because of the known tritium permeation and separation problems (nuclear power plants), the palladium-tritium system may become of particular interest, the solubility of 3H in Pd at low pressures (1.3 to 50 mbar) and tem­ peratures (25 to 70 °C) was analysed again [6]. For this purpose an apparatus was constructed permit­ ting the exact determination of absorptionand desorption-isotherms with only about 2 cm3 stp of tritium gas.

Heat transfer characteristics of porous metallic matrix metal-hydrides

Abstract: In order to overcome the difficulty of the poor heat transfer response of a powder bed, metal-hydrides (m-h) consolidated into a highly porous metallic matrix have been suggested. The steady state and transient heat transfer characteristics of the porous matrix metal hydride (pmh) were evaluated and shown to be better than those of m-h. The effect of improved heat transfer features of the pmh on the design of hydrogen storage devices was discussed. The heat transfer performance of pmh vs m-h during the hydrogen charge and discharge processes were discussed.

Low energy process for synthesis of ammonia

Abstract: An improved process for the synthesis of ammonia utilizing three catalyst beds wherein the temperature of the synthesis feed gas and the effluent of at least one of the catalyst beds is controlled without the addition of quench gas.

Metal material for hydrogen storage

Abstract: PURPOSE:The practical material for hydrogen storage;which is obtained by the combination of abundant Ca in Ca-Ni system alloys, occuludes very large amount of hydrogen per unit weight and is low in the palteou pressure

Calculated heats of formation of metal and metal alloy hydrides

Abstract: The basic features of the electronic structure of transition metal hydrides are understood. Results of the first ab initio calculation of the trends of the heat of formation of transition metal hydrides are discussed, and the basic one-electron energy difference technique is extended to consider the heat of formation of TiFeH 2 and TiPdH 2 . The present calculational method may be useful in suggesting practical hydrogen storage media, but the accuracy is not sufficiently high that one can quantitatively predict the heat of formation. For more precise results it will be necessary to carry out calculations which include the effects of charge self-consistency, which are treated in the present method by perturbation theory.

Materials problems in large scale production of hydrogen from water and in hydroge storage

Abstract: Methods for the production of hydrogen from water are discussed with emphasis on thermochemical cycles. These consist of a series of reactions, performed at various temperatures up to about 1000°C, which by their nature involve some compounds that are aggressive toward containment materials. Experience with most such reactions is presently not available in the chemical industry, and a lack of knowledge is thus evident regarding corrosion-resistant materials. The most promising thermochemical cycles are described in terms of the aggressiveness of their reagents. Materials problems associated with the production of hydrogen by water electrolysis and hydrogen storage in the form of metallic hydrides are also reviewed.