Synthetic Hydrocarbon Fuel for APU Application: The Fuel Processor System

Fuel cell Auxiliary Power Units (APUs) can use a variety of fuels as a hydrogen carrier. Projects showing the use of hydrogen as a fuel for an APU have been completed and the prospects of using methanol as an alternative fuel has been discussed before.

Despite the success of the previous fuel cell APU demonstrations, potential military and commercial customers desire a single on-board fuel for the main propulsion engine and for the APU. Such an application would require a fuel processor that can produce sufficiently pure hydrogen for utilization in a fuel cell from prevailing hydrocarbon fuels. The position of the U.S. Army's National Automotive Center (NAC) is to address this challenge by first using a synthetic diesel fuel as part of a phased fuel reformation program.

This paper presents an analysis of the use of a synthetic fuel as a hydrogen carrier. The paper focuses on the fuel processor system, main results achieved during the two phase program and the challenges that remain to be faced during the technology development.