Partial oxidation of ethanol in a membrane reactor for high purity hydrogen production

Partial oxidation of ethanol was performed in a dense Pd–Ag membrane reactor over Rh/Al2O3 catalyst in order to produce a pure or, at least, COx-free hydrogen stream for supplying a PEM fuel cell. The membrane reactor performances have been evaluated in terms of ethanol conversion, hydrogen yield, COx-free hydrogen recovery and gas selectivity working at 450 °C, GHSV ∼ 1300 h−1, O2:C2H5OH feed molar ratio varying between 0.33:1 and 0.62:1 and in a reaction pressure range from 1.0 to 3.0 bar. As a result, complete ethanol conversion was achieved in all the experimental tests. A small amount of C2H4 and C2H4O formation was observed during reaction. At low pressure and feed molar ratio, H2 and CO are mainly produced, while at stronger operating conditions CH4, CO2 and H2O are prevalent compounds. However, in all the experimental tests no carbon formation was detected. As best results of this work, complete ethanol conversion and more than 40.0% COx-free hydrogen recovery were achieved.Furthermore, at 450 °C, ambient pressure and stoichiometric feed molar ratio, partial oxidation of ethanol was performed in the Pd–Ag membrane reactor as a case study without using any catalyst. In this case, Pd–Ag membrane acts as a catalyst on the reaction. As a result, an ethanol conversion around 85% was reached, while low COx-free hydrogen recovery and carbon formation was the main drawback.