For the safe and trouble-free operation of an autothermal reformer there is a need of knowledge about the interactions between the reactions and the fluid dynamic. To answer technological questions about the reactors operating response a model was developed that allows the simulation of different consecutive states like load changes and start up procedures. The presented model was created to support the research work performed with the High Pressure Partial Oxidation test plant (HP-POX) at the Institute for Energy Process Engineering and Chemical Engineering (IEC) of the Technical University Bergakademie Freiberg (Freiberg, Germany), a joint venture with the Lurgi AG. (C) 2007 Elsevier B.V. All rights reserved.