Abstract
The dynamic performance of fuel-processors is critical for their automotive on-board application. In order to keep additional storage capacities to a minimum, a fast tracking of the hydrogen demand of the fuel-cell is essential. However, so far, little is known about the dynamic behavior of reformer systems. In order to gain a deeper understanding of the dynamic behavior, a detailed dynamic model for an experimental auto-thermal gasoline reformer has been developed. The reformer, a monolithic catalytic reactor, is modeled as a system of one-dimensional partial differential equations for mass and energy transport coupled to a simplified surface reaction mechanism. Surface occupancies of intermediate species are treated as dynamic states in order to allow an assessment of the importance of surface dynamics for the system behavior. Parameters for the reaction kinetics are obtained either from literature or estimated from measurements performed on a dynamic fuel-processor test bench built at our lab. Model versus experiment comparisons are presented for steady-state as well as for dynamic input step changes, indicating a good model agreement. For the input steps, it is shown that the non-ideal behavior of the test bench´s reactant supply strongly influences the transient hydrogen output and simulations results for an ideal input steps are presented.
Keywords:Fuel processing, Gasoline reforming, Dynamic modeling, Transient operation, Reaction kinetics