Combined Carbon Dioxide Reforming with Steam Reforming of Ethanol for Hydrogen Production: Thermodynamic Analysis

Abstract

In this work, the thermodynamic property of combined carbon dioxide and steam reforming of ethanol to generate hydrogen for fuel cells is studied. The effects of operating conditions such as pressure, temperature, and feed reactants ratio on the ethanol reforming process were analyzed by Gibbs free energy minimization method. The optimum conditions for hydrogen-rich gas production are identified: reaction temperatures between 1100 and 1200 K, carbon dioxide-to-ethanol molar ratio of 2, and steam-to-ethanol molar ratio of 3 at 1 atm. Under the optimal conditions, complete conversion of ethanol, 3.40–3.57 mol hydrogen/mol ethanol and 2.42–2.60 mol carbon monoxide/mol ethanol, could be achieved in the absence of coke formation. The combined carbon dioxide and steam reforming of ethanol is suitable for providing hydrogen-rich fuels for a solid oxide fuel cell. The coke-formed and coke-free regions are found, which are useful in guiding the search for suitable catalysts for the reaction.

Keywords:

• Hydrogen
• Carbon dioxide reforming
• Steam reforming
• Ethanol
• Thermodynamic

ACKNOWLEDGMENT

The financial support of this work by the China Postdoctoral Science Foundation Funded Project (no. 20090460021) is gratefully acknowledged.