Documents disponibles écrits par cet auteur

Application of a GaPO4 crystal microbalance for the detection of coke formation in high-temperature reactors and solid oxide fuel cells / Jason Millichamp in Industrial & engineering chemistry research, Vol. 50 N° 13 (Juillet 2011) 

Public ISBD [article]  in Industrial & engineering chemistry research > Vol. 50 N° 13 (Juillet 2011) . - pp. 8371-8375 Titre : Application of a GaPO4 crystal microbalance for the detection of coke formation in high-temperature reactors and solid oxide fuel cells Type de document : texte imprimé Auteurs : Jason Millichamp, Auteur ; Ebrahim Ali, Auteur ; Nigel P. Brandon, Auteur Année de publication : 2011 Article en page(s) : pp. 8371-8375 Note générale : Chimie industrielle Langues : Anglais (eng) Mots-clés : Solid  oxide  fuel  cell  Reactor  Coke  deposition Résumé : Piezoelectric crystal microbalance devices based on gallium orthophosphate (GaPO4) have recently become commercially available. This material allows for operation at over 900 °C and therefore has potential as an analytical technique for the study of surface reactions at high temperatures. This paper describes preliminary work to assess the suitability of this technology for such applications. Change in oscillation frequency associated with temperature and gaseous environment is studied, and the ability to detect coke formation on a Ni-modified crystal is demonstrated. These results suggest that the technology can be developed as a low cost, high sensitivity gravimetric sensor for monitoring surface processes in high temperature chemical reactors such as reformers and solid oxide fuel cells (SOFCs). DEWEY : 660 ISSN : 0888-5885 En ligne : http://cat.inist.fr/?aModele=afficheN&cpsidt=24332164 [article] Application of a GaPO4 crystal microbalance for the detection of coke formation in high-temperature reactors and solid oxide fuel cells [texte imprimé] / Jason Millichamp, Auteur ; Ebrahim Ali, Auteur ; Nigel P. Brandon, Auteur . - 2011 . - pp. 8371-8375. Chimie industrielle Langues : Anglais (eng) in Industrial & engineering chemistry research > Vol. 50 N° 13 (Juillet 2011) . - pp. 8371-8375 Mots-clés : Solid  oxide  fuel  cell  Reactor  Coke  deposition Résumé : Piezoelectric crystal microbalance devices based on gallium orthophosphate (GaPO4) have recently become commercially available. This material allows for operation at over 900 °C and therefore has potential as an analytical technique for the study of surface reactions at high temperatures. This paper describes preliminary work to assess the suitability of this technology for such applications. Change in oscillation frequency associated with temperature and gaseous environment is studied, and the ability to detect coke formation on a Ni-modified crystal is demonstrated. These results suggest that the technology can be developed as a low cost, high sensitivity gravimetric sensor for monitoring surface processes in high temperature chemical reactors such as reformers and solid oxide fuel cells (SOFCs). DEWEY : 660 ISSN : 0888-5885 En ligne : http://cat.inist.fr/?aModele=afficheN&cpsidt=24332164

Microstructural modeling of solid oxide fuel cell anodes / Joshua Golbert in Industrial & engineering chemistry research, Vol. 47 N°20 (Octobre 2008) 

Public ISBD [article]  in Industrial & engineering chemistry research > Vol. 47 N°20 (Octobre 2008) . - P. 7693-7699 Titre : Microstructural modeling of solid oxide fuel cell anodes Type de document : texte imprimé Auteurs : Joshua Golbert, Auteur ; Adjiman, Claire S., Auteur ; Nigel P. Brandon, Auteur Année de publication : 2008 Article en page(s) : P. 7693-7699 Note générale : Chemical engineering Langues : Anglais (eng) Mots-clés : Solid  Oxide  Fuel  Cell  (SOFC)  Electrodes  SOFC Résumé : The design and manufacture of electrodes for use in SOFCs is one of the greatest challenges to the commercialization of fuel cell technology. Composite SOFC electrodes mix three phases (ion conducting, electron conducting, pore phase) in order to improve performance by increasing the amount of triple-phase boundaries (TBPs)—meetings of the ionic and electronic pathways with the percolating gas network—where the redox reaction takes place. The electrode microstructure is critical since electrode performance is directly dependent on the abundance of TPBs and the transport properties of the three phases.A fundamental understanding of the quantitative effects of microstructure on electrode performance is required. However, electrode models commonly neglect heterogeneity and assume effective values for key parameters. In contrast, we present a computational framework that can readily be linked to experimental studies of microstructure, thereby providing crucial insight into the conditions and competing processes in the porous microstructure, insight that can be used to design future generations of electrodes. In the proposed methodology, a virtual electrode is generated by randomly placing spherical particles in a packed bed. The particles are then expanded to simulate sintering to ensure large contact surfaces between the different phases. Once the porous structure is obtained, we can analyze the porosity and percolation of the various phases and the amount of triple-phase boundary and its percolation throughout the electrode. Furthermore, the transport and redox phenomena are also modeled to determine the potential, current, and chemical distribution throughout the different phases. We are then able to predict electrode performance based on fundamental properties of the underlying microstructure. These results are used to relate microstructural properties to electrode performance. The microstructural properties can include porosity, particle radii, and radius ratio and the effect of graded electrodes. The method is tested on model systems and used to demonstrate the effect of particle size on performance. En ligne : http://pubs.acs.org/doi/abs/10.1021/ie800065w [article] Microstructural modeling of solid oxide fuel cell anodes [texte imprimé] / Joshua Golbert, Auteur ; Adjiman, Claire S., Auteur ; Nigel P. Brandon, Auteur . - 2008 . - P. 7693-7699. Chemical engineering Langues : Anglais (eng) in Industrial & engineering chemistry research > Vol. 47 N°20 (Octobre 2008) . - P. 7693-7699 Mots-clés : Solid  Oxide  Fuel  Cell  (SOFC)  Electrodes  SOFC Résumé : The design and manufacture of electrodes for use in SOFCs is one of the greatest challenges to the commercialization of fuel cell technology. Composite SOFC electrodes mix three phases (ion conducting, electron conducting, pore phase) in order to improve performance by increasing the amount of triple-phase boundaries (TBPs)—meetings of the ionic and electronic pathways with the percolating gas network—where the redox reaction takes place. The electrode microstructure is critical since electrode performance is directly dependent on the abundance of TPBs and the transport properties of the three phases.A fundamental understanding of the quantitative effects of microstructure on electrode performance is required. However, electrode models commonly neglect heterogeneity and assume effective values for key parameters. In contrast, we present a computational framework that can readily be linked to experimental studies of microstructure, thereby providing crucial insight into the conditions and competing processes in the porous microstructure, insight that can be used to design future generations of electrodes. In the proposed methodology, a virtual electrode is generated by randomly placing spherical particles in a packed bed. The particles are then expanded to simulate sintering to ensure large contact surfaces between the different phases. Once the porous structure is obtained, we can analyze the porosity and percolation of the various phases and the amount of triple-phase boundary and its percolation throughout the electrode. Furthermore, the transport and redox phenomena are also modeled to determine the potential, current, and chemical distribution throughout the different phases. We are then able to predict electrode performance based on fundamental properties of the underlying microstructure. These results are used to relate microstructural properties to electrode performance. The microstructural properties can include porosity, particle radii, and radius ratio and the effect of graded electrodes. The method is tested on model systems and used to demonstrate the effect of particle size on performance. En ligne : http://pubs.acs.org/doi/abs/10.1021/ie800065w