Oxidative steam reforming of ethanol over Rh based catalysts in a micro-channel reactor

Oxidative steam reforming of ethanol (OSRE) was studied over Rh/CeO2/Al2O3 catalysts in a micro-channel reactor. First, the catalyst support, Al2O3, was deposited on to the metallic substrate by washcoating and then the CeO2 and active metal were sequentially impregnated. The effect of support composition as well as active metal composition on oxidative steam reforming of ethanol in a micro-channel reactor was studied at atmospheric pressure, with water to ethanol molar ratio of 6 and oxygen to ethanol molar ratio ranging from 0.5 to 1.5, over a temperature range of 350–550 °C. Ceria added to 1%Rh/Al2O3 showed higher activity and selectivity than 1%Rh/Al2O3 alone. Out of the various catalysts tested, 2%Rh/20%CeO2/Al2O3 performed well in terms of activity, selectivity and stability. The OSRE performance was compared with that of SRE over 2%Rh/20%CeO2/Al2O3 catalyst at identical operating conditions. Compared to SRE, the activity in OSRE was higher; however the selectivity to desired products was slightly lower. The H2 yield obtained in OSRE was ∼112 m3 kg−1 h−1, as compared to ∼128 m3 kg−1 h−1 in SRE. The stability test performed on 2%Rh/20%CeO2/Al2O3 at 500 °C for OSRE showed that the catalyst was stable for ∼40 h and then started to deactivate slowly. The comparison between packed bed reactor and micro-channel reactor showed that the micro-channel reactor can be used for OSRE to produce hydrogen without any diffusional effects in the catalyst layer.