Steam reforming of ethanol over Rh/CeO2/Al2O3 catalysts in a microchannel reactor

Steam reforming of ethanol was studied over Rh/CeO2/Al2O3 catalysts in a micro-channel reactor. First, the catalyst support was deposited on to the metallic substrate by washcoating and then the CeO2 and active metal were sequentially impregnated. The catalysts were characterized by means of BET surface area, temperature programmed reduction. H-2 chemisorption and atomic absorption spectroscopy. The effect of support composition as well as active metal composition on steam reforming of ethanol in microchannel reactor was studied at atmospheric pressure, with an ethanol to water molar ratio of 1:6, over a temperature range of 400-600 degrees C. Ceria added to 2%Rh/Al2O3 showed higher activity and selectivity than 2%Rh/Al2O3 alone. With addition of Ni to 2%Rh/20%CeO2/Al2O3, the catalyst activity was significantly reduced. Out of the various catalysts tested, 2%Rh/20%CeO2/Al2O3 performed well in terms of activity, selectivity and stability. The micro-channel reactor performance was compared with that of packed bed reactor using 2%Rh/20%CeO2/Al2O3 catalyst at identical operating conditions. The activity was similar in both the reactors but the selectivity to desired products were higher in the micro-channel reactor. The H-2 yield obtained in the micro-channel reactor was similar to 65 Lg(-1) h(-1), as compared to 60 L-H2 g(-1) h(-1) in the packed bed reactor. The stability test performed on 2%Rh/20%CeO2/Al2O3 at 500 degrees C in the micro-channel reactor showed that the catalyst was stable for similar to 35 h and then started to deactivate slowly. (C) 2010 Elsevier B.V. All rights reserved.