Heat generation from swirl-stabilized aluminum-air flames

Author: Jean-François Brilhac,Olivier Allgaier,Cornelius Schönnenbeck,Yasmine Ouledi,Valerie Tschamber,Ulrich S. Schubert,Elke Schweers,Norbert Windhab,Lawrence Portugues
Publication: Fuel
Publisher: Elsevier
Date: 1 February 2025
 

https://doi.org/10.1016/j.fuel.2024.133494

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To limit global warming, new ways of transporting and storing energy are required. In such a context, metals are currently being considered as suitable energy carriers. In this investigation, aluminum-air flames were stabilized by a swirled-flow in a combustion chamber for heat production. Commercial Al particles were tested in various size range (from 0 to 400  µm). The total air flow rate injected varied from 5.6 (n)m3/h to 8 (n)m3/h corresponding to geometric swirl number ranging from 0.7 to 28. Self-igniting and continuous aluminum flames stopped after more than five minutes were established. Aluminum particles in the size range 0 to 36  µm were needed to ignite the flame. Indeed, no flame ignition was obtained with the 36 to 50 µm size range under these conditions. Increasing the swirl number from 7 to 14 and 28 enabled increasing the overall Al conversion rate. More than 45 % of the heat delivered by aluminum combustion was recovered in the combustion chamber which was water-cooled. Samples collected in the combustion chamber were observed by optical microscopy. Some unburnt or partly burnt aluminum particles were observed mainly for the samples collected at the inlet of the combustion chamber.

Demonstration of the co-generation of heat and hydrogen by high-temperature oxidation of aluminum in steam

Author:  F. Halter,D. Keo,B. Grosselin,E. Schweers,L. Portugues,N. Windhab,U.S. Schubert,C. Chauveau
Publication: International Journal of Hydrogen Energy
Publisher:  Elsevier
Date: 10 February 2025

https://doi.org/10.1016/j.ijhydene.2025.01.116

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The development of a circular economy based on the storage of decarbonized energy is essential. A potential solution involves storing surplus (intermittent) green energy by converting metal oxides into metal powders. This is in particular effective in regions with preferred wind conditions and extreme exposure to sunlight. These powders, which can be transported safely, can then be used to release the stored energy as required in other parts of the world. An experimental method involves the oxidation of metal particles in steam to simultaneously generate heat and hydrogen. The first proof of this concept, which shows the full conversion of steam to hydrogen, is presented in this contribution.