Reforming of diesel fuel in a micro reactor for APU systems

Abstract

Reforming of diesel fuel in micro reactors is a challenging but very attractive way for converting conventional fuel in a hydrogen rich gas for fuel cells applied for electrical energy generation, e.g. in auxiliary power units. To understand diesel reforming and to compare the process with reforming of other substances, the reforming of possible diesel conversion intermediates (methane and propane) and of a first diesel surrogate, hexadecane, was examined isothermally in a microchannel reactor in this study using rhodium as catalyst. The product analysis was established with a special method on a gas chromatograph to analyse all substances in one run. It was observed that branched feed molecules are converted faster on the rhodium catalyst than the unbranched molecules, latter ones exhibiting a reciprocal dependency of turnover frequency on carbon atoms per molecule. These observations are a first hint for the kinetics of the reforming. In higher hydrocarbons the CH groups seem to be converted more easily than CH2. CC bonds seem to be converted in an adsorbed state of both C due to the reciprocal dependency and due to negligible byproduct formation. Moreover, the negligible byproduct formation and the reciprocal dependency lead to the assumption that most of the conversion in the microchannels is performed on the catalyst surface and not in the gas phase.