Thermodynamic analysis of hydrogen production via partial oxidation of ethanol

Abstract

Thermodynamic equilibrium of ethanol partial oxidation has been studied by Gibbs free energy minimization method for hydrogen production in the range of oxygen-to-ethanol molar ratio from 0 to 3, reaction temperature from 500 to 1400 K, pressure from 1 to 20 atm and nitrogen-to-ethanol molar ratio from 0 to 100. The optimal operation conditions were obtained, which are 1070–1200 K, oxygen-to-ethanol molar ratio of 0.6–0.8, and 1 atm. Under the optimal conditions, complete conversion of ethanol, 86.28–94.98% yield of hydrogen and 34.69–38.64% concentration of carbon monoxide could be achieved and at which no coke tends to form. The hydrogen-rich fuel obtained is suitable for the use in Molten Carbonate Fuel Cell and Solid Oxide Fuel Cell. Higher pressures have a negative effect on the hydrogen yield. Inert gases have a negative effect on the hydrogen yield at low nitrogen-to-ethanol molar ratios (below 40), but further increasing the concentrations of the inert gases increases the hydrogen yield slightly. Coke tends to form at lower temperatures and lower oxygen-to-ethanol molar ratios.