The catalytic activity of Pd-based systems for the combustion of methane has been tested with Pd loading constant and equal to 2% w/w; the samples were supported on alumina, ceria-doped alumina, lanthanium-doped alumina and zirconia. The tests were performed in isothermal conditions at 325, 350 and 375°C, on lean and stoichiometric conditions; the effect of the support on the catalytic activity was investigated. The support influences the activity due to interactions between support and the active phase, or by its morphological features; it can also have effect on the stability and thewater resistance. The behaviors during sulphur poisoning and regeneration were studied exposing the catalyst to different reaction atmospheres: lean, stoichiometric and alternating reduction pulse/lean combustion. The regeneration was performed with temperature step experiments. The regeneration performed with alternating lean combustion/reduction pulse was more effective due to activation of methane on metallic palladium.
E' stata testata l'attività catalitica di sistemi per la combustione di metano a base di palladio con carico costante pari al 2% supportati su allumina, allumina drogata con ceria, allumina drogata con ossido di lantanio e su zirconia. I test sono stati condotti in condizioni di reazione isoterme a 350°C e in atmosfera lean e stechiometrica, investigando l'effetto del supporto sull'attività catalitica. Il supporto influenza l'attività a causa dei legami che si instaurano tra fase attiva e supporto, oppure per le caratteristiche morfologiche; si ha un effetto anche sulla stabilità e resistenza all'avvelenamento da H2O, a seconda della natura del supporto. Si è studiato il comportamento all'avvelenamento da zolfo e in rigenerazione dei campioni sopra menzionati in diverse atmosfere di reazione: lean, stechiometrica e con pulsi riducenti alternati a combustione lean. La rigenerazione è stata effettuata con gradini di temperatura via via crescenti. La rigenerazione con pulsi riducenti alternati a combustione lean si è rivelata più efficace a causa dell'attivazione del metano sul palladio metallico.
Attività catalitica e comportamento all'avvelenamento da zolfo di sistemi a base di Pd per la combustione di CH4
FERRARA, LUIGI
2008/2009
Abstract
The catalytic activity of Pd-based systems for the combustion of methane has been tested with Pd loading constant and equal to 2% w/w; the samples were supported on alumina, ceria-doped alumina, lanthanium-doped alumina and zirconia. The tests were performed in isothermal conditions at 325, 350 and 375°C, on lean and stoichiometric conditions; the effect of the support on the catalytic activity was investigated. The support influences the activity due to interactions between support and the active phase, or by its morphological features; it can also have effect on the stability and thewater resistance. The behaviors during sulphur poisoning and regeneration were studied exposing the catalyst to different reaction atmospheres: lean, stoichiometric and alternating reduction pulse/lean combustion. The regeneration was performed with temperature step experiments. The regeneration performed with alternating lean combustion/reduction pulse was more effective due to activation of methane on metallic palladium.File | Dimensione | Formato | |
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https://hdl.handle.net/10589/543