Start-Up Behavior of Fuel Processors for PEM Fuel Cell Applications

This paper focuses on start-up technology for fuel processing systems with special emphasis on gasoline fueled burners. Initially two different fuel processing systems, an autothermal reformer with preferential oxidation and a steam reformer with membrane, are introduced and their possible starting strategies are discussed. Energy consumption for preheating up to light-off temperature and the start-up time is estimated. Subsequently electrical preheating is compared with start-up burners and the different types of heat generation are rated with respect to the requirements on start-up systems. Preheating power for fuel cell propulsion systems necessarily reaches up to the magnitude of the electrical fuel cell power output. A gasoline fueled burner with thermal combustion has been build-up, which covers the required preheating power. Independent from the ambient conditions, the burner itself starts up in less than 5 seconds and then directly provides the preheating power within its exhaust gas. The average emissions of the burner during operation are below 40 ppm CO, 25 ppm UHC and 15 ppm NOx.