Thermodynamics equilibrium analysis of carbon dioxide reforming of methane combined with steam reforming to synthesis gas was studied by Gibbs free energy minimization method to understand the effects of process variables such as temperature pressure and inlet CH(4)/H(2)O/CO(2) ratios on product distributions For this purpose the calculations were carried out at total pressures of 1 and 20 bar, and at ranges of temperature and steam to carbon ratios of 200-1200 degrees C and 0-0 50 respectively The results revealed that carbon dioxide reforming of methane combined with steam reforming process was controlled by different reactions with regard to the operating temperature pressure and varying feed compositions The H(2)/CO product ratio could be modified by changing the relative concentration of steam and CO(2) in the feed temperature and pressure depending on the downstream application (C) 2010 Professor T Nejat Veziroglu Published by Elsevier Ltd All rights reserved