The Use of Proton Exchange Membrane Fuel Cell Technology to Recover Gaseous Helium from Rocket Testing Systems

The use of a proton exchange membrane fuel cell system (PEMFCS) operated in an electrolytic mode at its limiting current density is demonstrated as a novel method to separate gaseous hydrogen (GH(2)) from gaseous helium (GHe). The amount of GH(2) removed was determined by measuring the inlet and outlet GH(2) mole fraction and the rate of the hydrogen oxidation reaction (HOR) using different techniques. The HOR was shown to be well-modeled as a first order mass transport limited process for dilute GH(2) streams at the limiting current density. A differential reactor model based on first order kinetics is presented to obtain an estimate of the active area required to remove specific quantities of GH(2). The active area and total volumetric flow rate of gas in the feed were found to be critical design considerations.