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Kovové materiály pro přechovávání vodíku
Soukup, Karel ; Rogut, J. ; Ludwik-Pardala, M. ; Wiatkowski, M. ; Šolcová, Olga
Another alternative is the redox cycle of iron/iron oxides which is presented here. Hydrogen storage is described as a reduction of iron oxides to metallic iron by hydrogen. Hydrogen production is achieved through the oxidation of iron with water steam. This contribution describes textural and transport properties of solid materials composed of iron and aluminium oxide phases which are believed to be promising for the hydrogen storage process.
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Termodynamické možnosti a omezení pro výrobu čistého vodíku pomocí chromu, manganu a niklu s využitím cyklického chemického procesu za nižších teplot
Siewiorek, A. ; Svoboda, Karel ; Rogut, J.
Thermodynamics and chemical equilibrium for reduction of Cr2O3 , Mn3O4 and NiO by hydrogen, carbon monoxide, model syngas and methane and for oxidation of the relevant Cr, MnO and Ni by steam has been studied in a temperature range 400 – 1000 K. Attention was concentrated also on possible formation of undesired soot, carbides and carbonates during reduction step leading to CO and CO2 formation in the steam oxidation step. Reduction of Cr2O3 and MnO to metallic Cr and Mn by hydrogen, CO or CH4 at temperatures 400 – 1000 K is thermodynamically excluded. Reduction of Mn3O4 and NiO by hydrogen, CO and CH4 at such lower temperatures is thermodynamically favourable.
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Termodynamické možnosti a omezení pro výrobu čistého vodíku pomocí železa s využitím cyklického chemického procesu za nižších teplot
Svoboda, Karel ; Slowinski, G. ; Rogut, J. ; Siewiorek, A.
Iron offers possibility of transformation of a reducing gas ( CO, syngas, methane etc.) into hydrogen by a cyclic process based on iron oxide reduction and release of hydrogen in the next step by steam oxidation. Thermodynamics and chemical equilibrium for reduction of magnetite by hydrogen, carbon monoxide, model syngas and methane and for oxidation of iron by steam has been studied in a temperature range 400 – 850 K. Attention was concentrated also on possible formation of undesired soot, iron carbide and iron carbonate as precursors for CO and CO2 formation in the steam oxidation step. Oxidation of iron by steam is thermodynamically favoured at temperatures 400 – 800 K enabling high hydrogen yields. Iron oxide (magnetite) reduction is the more difficult step, requiring rather higher temperature and higher CO, H2 or methane concentrations in gaseous mixtures.
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