Documents disponibles écrits par cet auteur

A comparison of ammonia borane dehydrogenation methods for proton-exchange-membrane fuel cell vehicles / Ahmad Al-Kukhun in Industrial & engineering chemistry research, Vol. 50 N° 15 (Août 2011) 

Public ISBD [article]  in Industrial & engineering chemistry research > Vol. 50 N° 15 (Août 2011) . - pp. 8824-8835 Titre : A comparison of ammonia borane dehydrogenation methods for proton-exchange-membrane fuel cell vehicles : hydrogen yield and ammonia formation and Its removal Type de document : texte imprimé Auteurs : Ahmad Al-Kukhun, Auteur ; Hyun Tae Hwang, Auteur ; Arvind Varma, Auteur Année de publication : 2011 Article en page(s) : pp. 8824-8835 Note générale : Chimie industrielle Langues : Anglais (eng) Mots-clés : Proton  exchange  membrane  fuel  cells  Dehydrogenation Résumé : Current promising methods to release hydrogen from ammonia borane (NH3BH3, AB; 19.6 wt % H2) including neat thermolysis, thermolysis in ionic liquid bmimCl with or without proton sponge, thermolysis with nano-BN and hydrothermolysis, were investigated for hydrogen yield and ammonia formation. It was found that even trace moisture influences AB dehydrogenation significantly. The hydrothermolysis at 85 °C (13.5 wt % H2, 1 mol % NH3) and thermolysis in bmimCl with 3 wt % moisture at 110 °C (13 wt % H2, 0.2 mol % NH3) methods were found to be the most promising. Since the target for a proton exchange membrane (PEM) fuel cell is an ammonia concentration less than 0.1 ppm, different purification methods were evaluated. Using experiments and simulations, the proposed ammonia removal method, involving absorption in water followed by adsorption on carbon, was optimized and tested. This study demonstrates that, with high hydrogen yield and an effective method to remove ammonia and borazine, AB dehydrogenation is an attractive approach to generate hydrogen for PEM fuel cell vehicle applications. DEWEY : 660 ISSN : 0888-5885 En ligne : http://cat.inist.fr/?aModele=afficheN&cpsidt=24395828 [article] A comparison of ammonia borane dehydrogenation methods for proton-exchange-membrane fuel cell vehicles : hydrogen yield and ammonia formation and Its removal [texte imprimé] / Ahmad Al-Kukhun, Auteur ; Hyun Tae Hwang, Auteur ; Arvind Varma, Auteur . - 2011 . - pp. 8824-8835. Chimie industrielle Langues : Anglais (eng) in Industrial & engineering chemistry research > Vol. 50 N° 15 (Août 2011) . - pp. 8824-8835 Mots-clés : Proton  exchange  membrane  fuel  cells  Dehydrogenation Résumé : Current promising methods to release hydrogen from ammonia borane (NH3BH3, AB; 19.6 wt % H2) including neat thermolysis, thermolysis in ionic liquid bmimCl with or without proton sponge, thermolysis with nano-BN and hydrothermolysis, were investigated for hydrogen yield and ammonia formation. It was found that even trace moisture influences AB dehydrogenation significantly. The hydrothermolysis at 85 °C (13.5 wt % H2, 1 mol % NH3) and thermolysis in bmimCl with 3 wt % moisture at 110 °C (13 wt % H2, 0.2 mol % NH3) methods were found to be the most promising. Since the target for a proton exchange membrane (PEM) fuel cell is an ammonia concentration less than 0.1 ppm, different purification methods were evaluated. Using experiments and simulations, the proposed ammonia removal method, involving absorption in water followed by adsorption on carbon, was optimized and tested. This study demonstrates that, with high hydrogen yield and an effective method to remove ammonia and borazine, AB dehydrogenation is an attractive approach to generate hydrogen for PEM fuel cell vehicle applications. DEWEY : 660 ISSN : 0888-5885 En ligne : http://cat.inist.fr/?aModele=afficheN&cpsidt=24395828

Diffusional effects in nickel oxide reduction kinetics / Peter Erri in Industrial & engineering chemistry research, Vol. 48 N°1 (Janvier 2009) 

Public ISBD [article]  in Industrial & engineering chemistry research > Vol. 48 N°1 (Janvier 2009) . - p. 4-6 Titre : Diffusional effects in nickel oxide reduction kinetics Type de document : texte imprimé Auteurs : Peter Erri, Editeur scientifique ; Arvind Varma, Editeur scientifique Année de publication : 2009 Article en page(s) : p. 4-6 Note générale : Chemical engineering Langues : Anglais (eng) Mots-clés : Nickel  oxide  Industrial  catalyst Résumé : Nickel is widely used as an industrial catalyst and has recently been investigated as an oxygen carrier in chemical looping combustion (CLC), which is a novel approach for power generation that offers inherent CO2 capture. However, prior studies have reported a wide range of activation energy values for nickel formation from the reduction of NiO by hydrogen. In the present work, this reaction was investigated using the Friedman isoconversional method for a series of thermogravimetric curves, which were obtained at varying heating rates. The intrinsic activation energy for the reduction of NiO was observed to be in the range of 91.8−94.5 kJ/mol, whereas values of 42.6 kJ/mol and ∼0 kJ/mol were found at intermediate and high heating rates, respectively, which correspond to intermediate and high temperatures. This demonstrates the presence of internal and external mass-transfer limitations during the reaction, and it provides a likely explanation for the varying activation energy values reported in prior work. Therefore, these findings emphasize the importance of assessing diffusional effects in the determination of reaction kinetics. En ligne : http://pubs.acs.org/doi/abs/10.1021/ie071588m [article] Diffusional effects in nickel oxide reduction kinetics [texte imprimé] / Peter Erri, Editeur scientifique ; Arvind Varma, Editeur scientifique . - 2009 . - p. 4-6. Chemical engineering Langues : Anglais (eng) in Industrial & engineering chemistry research > Vol. 48 N°1 (Janvier 2009) . - p. 4-6 Mots-clés : Nickel  oxide  Industrial  catalyst Résumé : Nickel is widely used as an industrial catalyst and has recently been investigated as an oxygen carrier in chemical looping combustion (CLC), which is a novel approach for power generation that offers inherent CO2 capture. However, prior studies have reported a wide range of activation energy values for nickel formation from the reduction of NiO by hydrogen. In the present work, this reaction was investigated using the Friedman isoconversional method for a series of thermogravimetric curves, which were obtained at varying heating rates. The intrinsic activation energy for the reduction of NiO was observed to be in the range of 91.8−94.5 kJ/mol, whereas values of 42.6 kJ/mol and ∼0 kJ/mol were found at intermediate and high heating rates, respectively, which correspond to intermediate and high temperatures. This demonstrates the presence of internal and external mass-transfer limitations during the reaction, and it provides a likely explanation for the varying activation energy values reported in prior work. Therefore, these findings emphasize the importance of assessing diffusional effects in the determination of reaction kinetics. En ligne : http://pubs.acs.org/doi/abs/10.1021/ie071588m

Underground coal gasification / Evgeny Shafirovich in Industrial & engineering chemistry research, Vol. 48 N° 17 (Septembre 2009) 

Public ISBD [article]  in Industrial & engineering chemistry research > Vol. 48 N° 17 (Septembre 2009) . - pp. 7865–7875 Titre : Underground coal gasification : a brief review of current status Type de document : texte imprimé Auteurs : Evgeny Shafirovich, Auteur ; Arvind Varma, Auteur Année de publication : 2009 Article en page(s) : pp. 7865–7875 Note générale : Chemical engineering Langues : Anglais (eng) Mots-clés : Coal  gasification  Industrial  reactors  Liquid  hydrocarbon  fuels Résumé : Coal gasification is a promising option for the future use of coal. Similarly to gasification in industrial reactors, underground coal gasification (UCG) produces syngas, which can be used for power generation or for the production of liquid hydrocarbon fuels and other valuable chemical products. As compared with conventional mining and surface gasification, UCG promises lower capital/operating costs and also has other advantages, such as no human labor underground. In addition, UCG has the potential to be linked with carbon capture and sequestration. The increasing demand for energy, depletion of oil and gas resources, and threat of global climate change lead to growing interest in UCG throughout the world. In this article, we review the current status of this technology, focusing on recent developments in various countries. En ligne : http://pubs.acs.org/doi/abs/10.1021/ie801569r [article] Underground coal gasification : a brief review of current status [texte imprimé] / Evgeny Shafirovich, Auteur ; Arvind Varma, Auteur . - 2009 . - pp. 7865–7875. Chemical engineering Langues : Anglais (eng) in Industrial & engineering chemistry research > Vol. 48 N° 17 (Septembre 2009) . - pp. 7865–7875 Mots-clés : Coal  gasification  Industrial  reactors  Liquid  hydrocarbon  fuels Résumé : Coal gasification is a promising option for the future use of coal. Similarly to gasification in industrial reactors, underground coal gasification (UCG) produces syngas, which can be used for power generation or for the production of liquid hydrocarbon fuels and other valuable chemical products. As compared with conventional mining and surface gasification, UCG promises lower capital/operating costs and also has other advantages, such as no human labor underground. In addition, UCG has the potential to be linked with carbon capture and sequestration. The increasing demand for energy, depletion of oil and gas resources, and threat of global climate change lead to growing interest in UCG throughout the world. In this article, we review the current status of this technology, focusing on recent developments in various countries. En ligne : http://pubs.acs.org/doi/abs/10.1021/ie801569r