Bio-ethanol steam reforming on Ni based catalyst. Kinetic study

In this work a kinetic study of steam reforming of ethanol using a nickel based catalyst in the temperature range 873–923 K was performed. Conversion monotonically increases with space time and temperature. At 923 K we obtained more than 5 mol of hydrogen per mole of ethanol. This hydrogen yield is high compared to values reported in the literature. CO yield increases with the space time and temperature while CO2 yield has a maximum at 923 K, which coincides with the space time at which the system reaches complete conversion. At larger residence time CO2yield decreases. CH4 yield is very low for all conditions studied but a maximum can also be seen with space time. Both CO2and CH4are intermediate products, while CO is a final product. The effect of adding H2 to the feed was studied. Analyzing the kinetic results we propose a model involving the following reactions:(E1) CH3CH2OH→CO+CH4+H2(E1) CH3CH2OH+H2O→CO2+CH4+2H2(R1) CH4+2H2O↔CO2+4H2(R2) CO2+H2↔CO+H2OThe first two involving ethanol are irreversible while the latter two are reversible. The surface reactions are the rate determining steps. Kinetic parameters were estimated using commercial software.

► Ethanol steam reforming kinetics using a Ni based catalyst was studied. ► From the analysis of products distribution reactions mechanism were proposed. ► Kinetics parameters of all reactions involved were estimated. ► Hydrogen in the feed favors the formation of carbon monoxide instead of carbon dioxide. ► The occurrence of WGSR or its inverse depends on operative conditions.