Green technologies are expected to play key roles in the European energy transition programs. One of the interesting technologies for such applications is the catalytic partial oxidation (CPO) where it provides highly efficient, compact and flexible solution. In this work the CPO of ethanol-water mixtures was studied on different catalysts formulations with the aim of investigating the role of the catalyst support on syngas yield and coke formation. Cordierite honeycomb monoliths were coated with Rh/α − Al2O3 and Rh/MgAl2O4, wash-coats, using a newly developed percolate-spin-coating technique and then were tested on the adiabatic CPO plant. In order to understand the behavior of the homogeneous and the heterogeneous re actions taking place in the CPO, the gas and the solid phases temperatures were measured along the reactor axis. Additionally, axial composition profiles were measured by analyzing local samples collected in situ using the spatially resolved sampling technique. The stability of the catalysts was monitored via the growth of the hotspot temperature observed in the CH4-CPO, a reference reacting system that is used to detect catalyst deactivation processes, in between ethanol CPO tests. Moreover, temperature programmed oxidation (TPO) of samples prepared from the spent catalysts were finally used to identify the impact of the catalyst formulation on the coke formation phenomena. The composition profiles show an almost complete ethanol conversion for both catalysts with no significant variation on the temperature profiles under the selected working conditions. Additionally, the results obtained for the magnesium aluminate supported catalysts, show a significant drop of ethylene concentration which is known as coke precursors thus, the carbon formation was partially suppressed on that formulation, as evidenced by the TPO.
Le tecnologie per la produzione di idrogeno verde dovrebbero svolgere un ruolo chiave nei programmi europei di transizione energetica. Una delle tecnologie promettenti per tali applicazioni è l’ossidazione parziale catalitica (CPO) che offre una soluzione altamente efficiente, compatta e flessibile. In questo lavoro è stata studiata la CPO di miscele etanolo-acqua utilizzando diverse formulazioni di catalizzatori con l’obiettivo di indagare il ruolo del supporto catalitico sulla resa di syngas e sulla formazione di coke. Monoliti a nido d’ape di cordierite sono stati rivestiti con dei washcoat di Rh/α − Al2O3 e Rh/MgAl2O4, utilizzando una nuova tecnica di rivestimento denominata percolato-spin-coating e poi testati su l’impianto adiabatico di CPO. Per comprendere il comportamento delle reazioni omogenee ed eterogenee che avvengono nel CPO, le temperature della fase gassosa e solida sono state misurate lungo l’asse del reattore. Inoltre, i profili di composizione assiale sono stati determinati analizzando campioni raccolti in situ tramite l’utilizzo di un capillare. La stabilità dei catalizzatori è stata studiate tramite il monitoraggio della crescita della temperatura dell’hotspot osservata nel CH4-CPO, svolti dopo ogni prova con l’etanolo. Infine, l’ossidazione a temperatura programmata (TPO) è stata infine utilizzata per identificare l’impatto della formulazione del catalizzatore sui fenomeni di formazione del coke. I profili di composizione mostrano una conversione dell’etanolo quasi completa per entrambi i catalizzatori testati, senza variazioni significative sui profili di temperatura nelle condizioni di lavoro selezionate. I risultati ottenuti per i catalizzatori supportati da alluminato di magnesio, mostrano un calo significativo della concentrazione di etilene, precursore del coke, e quindi, una parziale soppressione della formazione di carbonio, come evidenziato dal TPO.
Catalytic partial oxidation of ethanol on Rh coated monoliths : advanced catalyst formulation and coating techniques
Bressan, Matteo
2020/2021
Abstract
Green technologies are expected to play key roles in the European energy transition programs. One of the interesting technologies for such applications is the catalytic partial oxidation (CPO) where it provides highly efficient, compact and flexible solution. In this work the CPO of ethanol-water mixtures was studied on different catalysts formulations with the aim of investigating the role of the catalyst support on syngas yield and coke formation. Cordierite honeycomb monoliths were coated with Rh/α − Al2O3 and Rh/MgAl2O4, wash-coats, using a newly developed percolate-spin-coating technique and then were tested on the adiabatic CPO plant. In order to understand the behavior of the homogeneous and the heterogeneous re actions taking place in the CPO, the gas and the solid phases temperatures were measured along the reactor axis. Additionally, axial composition profiles were measured by analyzing local samples collected in situ using the spatially resolved sampling technique. The stability of the catalysts was monitored via the growth of the hotspot temperature observed in the CH4-CPO, a reference reacting system that is used to detect catalyst deactivation processes, in between ethanol CPO tests. Moreover, temperature programmed oxidation (TPO) of samples prepared from the spent catalysts were finally used to identify the impact of the catalyst formulation on the coke formation phenomena. The composition profiles show an almost complete ethanol conversion for both catalysts with no significant variation on the temperature profiles under the selected working conditions. Additionally, the results obtained for the magnesium aluminate supported catalysts, show a significant drop of ethylene concentration which is known as coke precursors thus, the carbon formation was partially suppressed on that formulation, as evidenced by the TPO.File | Dimensione | Formato | |
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https://hdl.handle.net/10589/177467