The effect of impurities on the steam reforming of ethanol over ruthenium/alumina

Steam reforming of bioethanol is a promising route for H-2 production. However, the presence of impurities in technical bioethanol has a significant influence on the activity and lifetime of the catalyst. Therefore, the aim of this project was to study the influence of C-3-impurities (1-propanol, 2-propanol (IPA), propanal, acetone and propyl amine) on the steam reforming of ethanol over Ru/Al2O3 at 773 K and 20 barg. It was found that the addition of C-3-alcohols significantly decreased the conversion of ethanol and increased the rate of catalyst deactivation. This deactivation of the catalyst in the presence of C-3-alcohols was attributed to high olefin formation and incomplete decomposition of the C-3-alcohols, which resulted in coke formation over the catalyst. In contrast propyl amine and acetone addition maintained high ethanol conversion throughout the time on stream. However analysis of the product distribution suggested that the main reaction was ethanol decomposition taking place over the support and that the metal was completely deactivated for steam reforming. The addition of acetone to ethanol also significantly changed the nature of coke from graphitic to amorphous carbon. The addition of propanal resulted in behaviour initially akin to propanol but eventually moved to selectivity similar to that found with acetone.