High Temperature Electrochemical Hydrogen Pump Cell Using a PBI Membrane at High Current Densities

Abstract

The ability of an electrochemical hydrogen pump cell employing a polybenzimidazole membrane imbibed with phosphoric acid to purify hydrogen rich streams has been investigated. It has been found that pure hydrogen can be produced from diluted hydrogen and from typical reformate feeds with less than 5 kW-hrs required per kilogram of hydrogen pumped. The performance of these cells does not degrade under pure hydrogen over 24 hours for current densities up to 0.4 A/cm2. However, in less than 10 hours, the polarization effects had increased by 10% under pure hydrogen at 1.0 A/cm2 and by 50% under reformate at 0.2 A/cm2. However, the performance degradation caused by the presence of CO was observed to be reversible by switching the cell polarization and flows.