Fast start-up of a diesel fuel processor for PEM fuel cells

•Fuel processor based on diesel steam reforming developed for PEM fuel cells.•Novel start-up strategy developed for reactive heating of WGS and PROX using OSR.•Multifunctional reactors work as start-up burners and reactant conditioners.•Reactive heating of the fuel processor is 9 min faster than sequential heating.•Until SR operation 5.9 MJ fuel and 13 Ah (12 V) electric energy is consumed.

Fuel cell systems based on liquid fuels are particularly suitable for auxiliary power generation due to the high energy density of the fuel and its easy storage. Together with industrial partners, Oel-Waerme-Institut is developing a 3 kWel PEM fuel cell system based on diesel steam reforming to be applied as an APU for caravans and yachts. The start-up time of a fuel cell APU is of crucial importance since a buffer battery has to supply electric power until the system is ready to take over. Therefore, the start-up time directly affects the battery capacity and consequently the system size, weight, and cost.In the presented work a novel start-up strategy for the steam reforming fuel processor is introduced. The new approach includes the reactive heating of WGS reactors by using reformate from oxidative steam reforming (OSR) instead of the sequential heating of the fuel processor. The start-up procedure is demonstrated on a 10 kW steam reformer and a parameter study is carried out. Subsequently, the new procedure is tested on the complete fuel processor. Here, the OSR operation starts after 15:20 min and provides reformate for reactive heating of the WGS reactors. Steam reforming operation can be started after 23:40 min, which is 9 min earlier than applying sequential heating of the fuel processor. Until SR operation, the total energy consumption sums up to up to 5.9 MJ fuel and 13 Ah (12 V) electric energy.