Tunable Diode Laser Based Concentration Measurements of Water Vapour and Methane on a Solid Oxide Fuel Cell

This paper presents concentration measurements of water vapour and methane, taken in-situ on an operational solid oxide fuel cell (SOFC) test rig using tunable diode laser spectroscopy (TDLS). Methane concentration measurements are presented for the TDLS system and are compared with concentration measurements taken using gas chromatography (GC). Furthermore, purge times for the SOFC gas-analysis system have been calculated using TDLS, which are measurements that cannot be obtained directly using GC. Finally, water vapour concentration measurements in the SOFC cathode are shown for different system operating conditions: a dry cathode cycle and during the introduction of water vapour. As GC cannot be used to measure water vapour in the SOFC cathode stream, a direct comparison cannot be made with the TDLS measurements.