Steam reforming of ethanol at medium pressure over Ru/Al2O3: effect of temperature and catalyst deactivation

Abstract

In this study a low-loaded 0.2% Ru/alumina catalyst was tested over a range of temperatures (773-873 K) at 20 barg with a 5 : 1 steam to ethanol ratio. Ruthenium was found to produce significant amounts of ethene, although in the steady state hydrogen was always the main product. Significant levels of methane and carbon dioxide were formed at 873 K. Hydrogenation of ethene to ethane was inhibited and an activation energy comparable with low temperature studies was obtained. Liquid products such as acetaldehyde, diethyl ether and acetone were also produced at low levels (o12%). Temperature-programmed oxidation (TPO), Raman spectroscopy, powder XRD, BET and SEM analysis were used to characterise the nature of the coke species for reactions at 773 K, 823 K and 873 K. The TPO results indicate that different types of coke are deposited on the catalyst during ethanol steam reforming (ESR). Carbon nanotubes and filamentous coke were observed on the catalyst after ESR at 873 K. Powder XRD and Raman analysis revealed that the coke deposited on the catalysts was graphitic in nature and the disorder in the graphitic type coke generally increased with in an increase in the reaction temperature.

Ethanol steam reforming over Pt/Al 2 O 3 and Rh/Al 2 O 3 catalysts: The effect of impurities on selectivity and catalyst deactivation

“…1-propanol was also 18 highly deleterious reducing the conversion to ~30 % after 100 h TOS. Propanal and propylamine reduced the conversion to levels similar to that for pure ethanol after 100 h even though initially they gave higher conversion.…”

“…In a previous study [18] it was shown that alumina does not catalyse steam reforming of ethanol but instead catalyses ethanol decomposition and the water gas shift (WGS) reaction. The results from the reaction, over the alumina support, of ethanol with 1-propanol and propyl amine as added impurities have been previously reported [17] and show similar behaviour in that the product distributions confirm that the only reactions occurring are ethanol 10 decomposition and WGS.…”

“…acetaldehyde, are not shown.) 26 As we have outlined previously this underestimates the hydrogen yield as it takes no account of hydrogen produced during carbon laydown [17][18][19]. Nevertheless it does give a correct carbon and oxygen balance.…”

“…In previous papers we investigated the effect of temperature on the ESR reaction over Ru/alumina [18] and Rh/alumina and Pt/alumina [1] and then the effect of impurities on the ESR reaction over Ru/alumina [17]. Ruthenium had been chosen as it had shown some resistance to poisoning [20] however we found that many of the impurities had significant effects on the ethanol conversion and dry gas selectivity.…”

Catalisadores de Ni suportados em Al₂O₃ modificados com V, Nb e Zn aplicados na reforma à vapor do ácido butírico para produção de H₂

“…Novos processos para a geração de energia alternativa e limpa são bastante pesquisados e cerca de 80 % da necessidade energética mundial é suprida, direta ou indiretamente, a partir de combustíveis fósseis (HAN et al, 2013;BILAL;JACKSON, 2012).…”