A laboratory gas circulation pump has been built in which the pump driving force is obtained by the alternate decomposition and regeneration of vanadium dihydride (VH2). This cyclic action is accomplished by alternately heating and cooling the hydride system using hot (50°C) and cold (18°C) water. The particular pump described is suitable for the circulation of gases in systems where the pressure range is between 7 and 24 atm.

Metal hydrides as a source of hydrogen fuel

A New Laboratory Gas Circulation Pump for Intermediate Pressures

Modeling studies are of a practical importance in understanding and characterizing the behavior of hydride beds now being developed for storing and supplying hydrogen fuel in power plant and automotive applications. A convection bed model, in which heat is transferred to or from the bed by a flowing stream of hydrogen in direct contact with the particles, and a conduction model in which heat is transferred through a containment wall, were developed. FeTiH2 and catalyzed MgH2 were evaluated using the model.

Modeling Studies of Fixed-Bed Metal-Hydride Storage Systems

L’utilisation des combustibles fossiles est responsable de l’augmentation de la concentration en gaz a effet de serre dans l’atmosphere. Parmi les solutions de remplacement envisagees, l’hydrogene constitue un vecteur d’energie tres interessant. Toutefois, cette solution ne sera envisageable que lorsque les problematiques liees a la production de l’hydrogene et a son stockage seront resolues.Le premier objectif de cette these porte sur la synthese et la caracterisation de composes ternaires a base de magnesium dans le systeme ternaire TR-M-Mg (avec TR = Terres Rares et M = metaux de transition) qui pourraient etre de bons candidats pour le stockage de l’hydrogene. Ces composes pourraient de plus avoir d’autres applications, notamment comme materiaux de structure, du fait de leur tres faible densite. La composition NdNiMg15 a fait l’objet d’une etude complete. Cette phase cristallise selon une symetrie quadratique avec a= 10,0602(1) et c= 7,7612(2) A et un groupe d’espace P4/nmm. Un ordre antiferromagnetique a 9 K est observe et la capacite massique de stockage reversible est de 4 %mass. Cette nouvelle phase a montre un effet durcissant sur le magnesium.Le deuxieme objectif de cette these concerne la production d’hydrogene par hydrolyse i) des composes ternaires TR-M-Mg qui pourrait etre consideree comme une possibilite economique et energetique pour valoriser les dechets de ces composes et ii) des melanges ternaires TR-M-Mg elabores par broyage mecanique. Le broyage a permis la creation des defauts favorisant ainsi la corrosion des metaux. De plus, la production d'hydrogene par hydrolyse des composites Mg-NdNiMg15 (70, 80 et 90 %mass. Mg) a ete realisee et comparee a celle du compose NdNiMg15 (64 %mass. en Mg). Le mecanisme de corrosion principal deduit des essais electrochimiques sur les composites est la corrosion galvanique.

background

Systèmes ternaires à base de magnésium : synthèse, structure, propriétés physiques, stockage et/ou production d’hydrogène

Thermodynamic modeling of the Mg-Ni-Y system is carried out as a part of multicomponent thermodynamic database for Mg alloys. This system is being modeled for the first time using the modified quasichemical model which considers the presence of short range ordering in the liquid. A self-consistent thermodynamic database for this system is constructed by combining the thermodynamic descriptions of the constituent binaries. Mg-Ni and Ni-Y binary systems have been re-optimized based on the experimental phase equilibrium and thermodynamic data available in the literature. The optimized thermodynamic parameters for the Mg-Y system are taken from the previous thermodynamic assessment of the Mg-Cu-Y system by the same authors. The constructed database is used to calculate and predict thermodynamic properties, the binary phase diagrams and isothermal section of the ternary Mg-Ni-Y system. The calculated results are found to be in good agreement with the experimental data.

/pdf/thermodynamic-evaluation-of-the-mg-ni-y-ternary-system-1b0puhtsu7.pdf

Metal hydrides as a source of hydrogen fuel

Citations

A New Laboratory Gas Circulation Pump for Intermediate Pressures

Modeling Studies of Fixed-Bed Metal-Hydride Storage Systems

Systèmes ternaires à base de magnésium : synthèse, structure, propriétés physiques, stockage et/ou production d’hydrogène

Thermodynamic Evaluation of the Mg-Ni-Y Ternary System

References

Hydrogen Compounds of the Metallic Elements

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