Thermodynamic analysis of hydrogen production for fuel cell via oxidative steam reforming of propane

Abstract

A thermodynamic analysis of hydrogen production from propane by oxidative steam reforming (OSR) is performed with a Gibbs free energy minimization method. Addition of oxygen reduces the enthalpy of the system and facilitates the heat supply. Equilibrium compositions of OSR as a function of temperature (300, 500, 700 and 900 °C), H 2O/C 3H 8 ratio (1.0–20.0) and O 2/C 3H 8 ratio (0.0–2.0) under oxidative and thermo-neutral (TN) conditions are evaluated. The results for oxidative conditions demonstrate that at 700 °C with H 2O/C 3H 8 ratios above 7.0 and/or O 2/C 3H 8 ratios higher than 1.3 are beneficial for hydrogen production which facilitates superior hydrogen yield, i.e. close to 9.0 mol/mol propane, with coke and methane formation reactions being suppressed effectively. For TN condition, autothermal temperature and equilibrium composition have a stronger dependence on O 2/C 3H 8 ratio than on H 2O/C 3H 8 ratio. Further calculations show that the condition at 700 °C with an appropriate H 2O/C 3H 8 ratio between 7.0 and 13.0 is favorable for achieving a high hydrogen yield and a low carbon monoxide yield. Therefore, a favorable operational range is proposed to ensure the most optimized product yield.