Comparing Anode Gas Recirculation with Hydrogen Purge and Bleed in a Novel PEMFC Laboratory Test Cell Configuration

In automotive-type polymer electrolyte membrane fuel cell (PEMFC) systems, impurities and inert gases accumulate in the anode gas recirculation loop. Therefore, the impurity limits, dictated by the current hydrogen fuel specification (ISO 14687-2:2012), also require quantification with representative fuel cell test systems applying anode gas recirculation, that enables high fuel utilization rates and accumulation of impurities.We report a novel PEMFC laboratory test cell configuration mimicking automotive conditions. This setup enabled comparison of two operation modes, hydrogen bleed and purge, within 84.4%-98.6% fuel utilizations. The results indicate that similar enrichment dynamics apply to both bleed and purge modes.The configuration employed a membrane dryer to circumvent the 60?°C limit of commercially available recirculation pumps. The membrane dryer allows heat and humidity extraction from the anode exit gas stream, enabling the adoption of conventional recirculation pumps, minimizing water condensation, and making sampling with on-line gas analysis instruments easier. The results show that anode gas recirculation systems with hydrogen bleed can be implemented in conventional test stations by resorting to commercially available recirculation pumps. This enables realistic and cost-effective determination of impurity effects for fuel cell system development and new hydrogen fuel standards.