Thermodynamic equilibrium for sorption enhanced steam reforming of butanol (SESRB) to hydrogen was investigated using Gibbs free energy minimization method. The optimal operation conditions for SESRB are at 800 K, the steam-to-butanol molar ratio of 10, the calcium oxide-to-butanol molar ratio of 8 and atmospheric pressure. Under the optimal conditions, complete conversion of butanol, 97.07% concentration of H(2) and 0.05% concentration of CO(2), and efficiency of 86.60% could be achieved and at which no coke tends to form. Under the same conditions in SRB, 58.18% concentration of H(2), 21.62% concentration of CO(2), and energy efficiency of 81.51% could be achieved. Butanol steam reforming with CO(2) adsorption has the higher H(2) content and efficiency, and lower CO(2) content than that without adsorption under the same reaction conditions. In addition, reaction conditions for coke-free and coke-formed regions are also discussed in butanol steam reforming with or without CO(2) separation. (C) 2010 Professor T. Nejat Veziroglu. Published by Elsevier Ltd. All rights reserved.