Hydrogen production from steam-methanol reforming: thermodynamic analysis

Thermodynamic equilibrium involved in the steam reforming of methanol is re -examined to cover the extended range of compounds suggested by literature to be involved in the reactions. The equilibrium concentrations are determi ned for different mixtures of these compounds at 1 atm and at different tem peratures (360-573 K) and at different steam/methanol molar feed ratios (0- 1.5), by the method of direct minimization of Gibbs free energy. The possib ility of carbon formation in these conditions is determined by direct inclu sion of carbon in the objective function of the minimization scheme. Result s showed that the area of carbon formation region is surprisingly high. Car bon and methane formations are thermodynamically favoured and they reduce t he quantity and quality of hydrogen produced. Dimethyl ether formation occu rs at low temperatures and low steam/carbon feed ratios, while carbon monox ide occurs at high temperatures and low steam carbon ratios. (C) 1999 Inter national Association for Hydrogen Energy. Published by Elsevier Science Ltd . All rights reserved.