Thermisch stabiles Upscaling einer exothermen Modellreaktion

Abstract

We consider a model exothermic radical reaction in a continuous flow stirred tank reactor, which converts an educt into a product via a starter radical. Optimal conversion rate is achieved in the limit of small starter concentration. Thermal stability requirements limit the maximal production rate. Specifically we consider upscaling of a miniplant by a factor σ > 1 of length scale. Then the maximally thermally admissible volumetric production rate which avoids hot spots scales by the same factor σ, only, rather than a naively expected factor σ³. This constraint is due to the nonlinearity of chemical mass action kinetics, thermal diffusion limitations, and the Arrhenius law. It is independent of the particular numerical values of the reaction rates.