Thermodynamic comparison between bio-oil and ethanol steam reforming

The thermodynamic analysis of the steam reforming (under catalytic steam reforming conditions) of a simulated bio-oil (composed of model compounds of components in a real bio-oil) and of ethanol is performed by minimization of Gibbs free energy method with Pro II-Simsci (R) 8.3 software, and their results are compared. At the equilibrium conditions both oxygenated feeds are completely converted, with H-2, CO2, CO and CH4 being the only significant gaseous products. Coke formation is observed below 700 degrees C for low steam/carbon (S/C) molar ratios (below the stoichiometric value). H-2 yield, which is very similar for both reforming processes (with small differences only for S/C < 2), increases with S/C ratio and goes through a maximum with temperature, being higher than 90% for S/C > 5 and in the 540-640 degrees C range. Above 600-650 degrees C (depending on the S/C molar ratio), the energy requirement for steam reforming of ethanol is slightly higher that for bio-oil steam reforming. These results evidence the viability of the joint valorisation of bio-oil and bio-ethanol by means of steam reforming. Copyright (C) 2015, Hydrogen Energy Publications, LLC. Published by Elsevier Ltd. All rights reserved.