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Conductive monolithic catalysts / Gianpiero Groppi in Industrial & engineering chemistry research, Vol. 51 N° 22 (Juin 2012) 

Public ISBD [article]  in Industrial & engineering chemistry research > Vol. 51 N° 22 (Juin 2012) . - pp. 7590-7596 Titre : Conductive monolithic catalysts : Development and industrial pilot tests for the oxidation of o - xylene to phthalic anhydride Type de document : texte imprimé Auteurs : Gianpiero Groppi, Auteur ; Enrico Tronconi, Auteur ; Carlotta Cortelli, Auteur Année de publication : 2012 Article en page(s) : pp. 7590-7596 Note générale : Industrial chemistry Langues : Anglais (eng) Mots-clés : Oxidation  Catalyst  Monolithic  construction Résumé : We present herein results from a campaign (>1500 h) of o-xylene oxidation runs in a 1 in. single-tube technical fixed- bed pilot reactor (i.d = 24.6 mm) loaded with 16 washcoated (V2O5/TiO2) monolithic catalysts with Al honeycomb supports (each 10 cm long) and operated at typical industrial conditions for PA (phthalic anhydride) production. The highly conductive monolithic supports afforded substantially reduced axial T-gradients in comparison with reference runs in the same pilot reactor loaded with conventional egg-shell ring catalyst pellets, the maximum T-difference with the salt bath being halved at the same hot spot temperature (∼440 °C) and the mean bed temperature being about 20 °C higher. Temperature gradients were still moderate at an o-xylene feed concentration of 80 g/Nm3 (at Qair = 4 N m3/h), which represents an upper limit for industrial PA packed-bed reactors loaded with the same V2O5/TiO2 catalyst coated onto ring pellets. Operation at higher o-xylene feed contents (up to 95 g/Nm3) was found feasible. The Al honeycomb catalysts were successfully unloaded at the end ofthe runs. The strong (∼2-fold) enhancement of radial heat transfer rates associated with the adoption of highly conductive monolith catalyst supports is thus herein demonstrated at a fully representative industrial scale for the first time. It can be exploited, for instance, either to increase the o-aylene feed concentration, possibly above 100 g/Nm3 (and the PA productivity accordingly), within a retrofitting strategy, or to design new reactors with larger tube diameters, resulting in reduced investment costs. ISSN : 0888-5885 En ligne : http://cat.inist.fr/?aModele=afficheN&cpsidt=25968312 [article] Conductive monolithic catalysts : Development and industrial pilot tests for the oxidation of o - xylene to phthalic anhydride [texte imprimé] / Gianpiero Groppi, Auteur ; Enrico Tronconi, Auteur ; Carlotta Cortelli, Auteur . - 2012 . - pp. 7590-7596. Industrial chemistry Langues : Anglais (eng) in Industrial & engineering chemistry research > Vol. 51 N° 22 (Juin 2012) . - pp. 7590-7596 Mots-clés : Oxidation  Catalyst  Monolithic  construction Résumé : We present herein results from a campaign (>1500 h) of o-xylene oxidation runs in a 1 in. single-tube technical fixed- bed pilot reactor (i.d = 24.6 mm) loaded with 16 washcoated (V2O5/TiO2) monolithic catalysts with Al honeycomb supports (each 10 cm long) and operated at typical industrial conditions for PA (phthalic anhydride) production. The highly conductive monolithic supports afforded substantially reduced axial T-gradients in comparison with reference runs in the same pilot reactor loaded with conventional egg-shell ring catalyst pellets, the maximum T-difference with the salt bath being halved at the same hot spot temperature (∼440 °C) and the mean bed temperature being about 20 °C higher. Temperature gradients were still moderate at an o-xylene feed concentration of 80 g/Nm3 (at Qair = 4 N m3/h), which represents an upper limit for industrial PA packed-bed reactors loaded with the same V2O5/TiO2 catalyst coated onto ring pellets. Operation at higher o-xylene feed contents (up to 95 g/Nm3) was found feasible. The Al honeycomb catalysts were successfully unloaded at the end ofthe runs. The strong (∼2-fold) enhancement of radial heat transfer rates associated with the adoption of highly conductive monolith catalyst supports is thus herein demonstrated at a fully representative industrial scale for the first time. It can be exploited, for instance, either to increase the o-aylene feed concentration, possibly above 100 g/Nm3 (and the PA productivity accordingly), within a retrofitting strategy, or to design new reactors with larger tube diameters, resulting in reduced investment costs. ISSN : 0888-5885 En ligne : http://cat.inist.fr/?aModele=afficheN&cpsidt=25968312

Experimental and modeling analysis of methane partial oxidation / Alessandra Beretta in Industrial & engineering chemistry research, Vol. 48 N° 8 (Avril 2009) 

Public ISBD [article]  in Industrial & engineering chemistry research > Vol. 48 N° 8 (Avril 2009) . - pp. 3825–3836 Titre : Experimental and modeling analysis of methane partial oxidation : transient and steady-state behavior of rh-coated honeycomb monoliths Type de document : texte imprimé Auteurs : Alessandra Beretta, Auteur ; Gianpiero Groppi, Auteur ; Matteo Lualdi, Auteur Année de publication : 2009 Article en page(s) : pp. 3825–3836 Note générale : Chemical engineering Langues : Anglais (eng) Mots-clés : Rh-coated  honeycomb  monoliths  Methane  partial  oxidation  Steady  state Résumé : The present study consists of an experimental and theoretical study of the performance of Rh-coated honeycomb monoliths for methane partial oxidation. The thermal behavior of Rh-coated honeycomb monoliths was studied under representative operating conditions, at steady state and during light-off. Model analysis (based on a dynamic heterogeneous reactor model that incorporates a kinetic scheme of the process independently developed, and well-assessed correlations for heat and mass transfer) provided a key for interpreting the observed effects. The comprehension of how transport phenomena and surface kinetics affect the reactor behavior leads to the conclusion that the feasibility of small-scale production of syngas via CH4 catalytic partial oxidation relies on thermal management of the short contact time reactor and not the obtainment of high syngas yields (which is not a challenging task). Severe operating conditions (and high surface temperatures) can deplete the catalyst activity and cause unstable reactor operation. Guidelines for optimal reactor design are proposed. En ligne : http://pubs.acs.org/doi/abs/10.1021/ie8017143 [article] Experimental and modeling analysis of methane partial oxidation : transient and steady-state behavior of rh-coated honeycomb monoliths [texte imprimé] / Alessandra Beretta, Auteur ; Gianpiero Groppi, Auteur ; Matteo Lualdi, Auteur . - 2009 . - pp. 3825–3836. Chemical engineering Langues : Anglais (eng) in Industrial & engineering chemistry research > Vol. 48 N° 8 (Avril 2009) . - pp. 3825–3836 Mots-clés : Rh-coated  honeycomb  monoliths  Methane  partial  oxidation  Steady  state Résumé : The present study consists of an experimental and theoretical study of the performance of Rh-coated honeycomb monoliths for methane partial oxidation. The thermal behavior of Rh-coated honeycomb monoliths was studied under representative operating conditions, at steady state and during light-off. Model analysis (based on a dynamic heterogeneous reactor model that incorporates a kinetic scheme of the process independently developed, and well-assessed correlations for heat and mass transfer) provided a key for interpreting the observed effects. The comprehension of how transport phenomena and surface kinetics affect the reactor behavior leads to the conclusion that the feasibility of small-scale production of syngas via CH4 catalytic partial oxidation relies on thermal management of the short contact time reactor and not the obtainment of high syngas yields (which is not a challenging task). Severe operating conditions (and high surface temperatures) can deplete the catalyst activity and cause unstable reactor operation. Guidelines for optimal reactor design are proposed. En ligne : http://pubs.acs.org/doi/abs/10.1021/ie8017143