Vergleich von kontinuierlichen Modellen zur Beschreibung des dynamischen: Verhaltens von katalytischen Festbettreaktoren

Abstract

The dynamic behavior of a catalytic fixed-bed reactor in the region of multiple steady states is simulated. Ignition and blow-out of a highly exothermic reaction are calculated using the diffusion model and several modifications of the two-phase model. The differences in the dynamic behavior of the models are discussed. The influences of the effective diffusion and the boundary conditions are studied. The effective heat conduction in the catalyst bed consists of the heat conduction in the fluid phase and that in the catalyst phase. The influence of the ratio of the heat conduction in the two phases is discussed. It can be seen that for the exothermic reaction considered the diffusion model requires much more numerical effort than the two-phase model. The reason is the extremely steep temperature profile which will be obtained by calculating the diffusion model.