Oxygen Distribution in Packed-Bed Membrane Reactors for Partial Oxidations:  Effect of the Radial Porosity Profiles on the Product Selectivity

A two-dimensional, pseudohomogeneous reactor model was presented to describe the radial and axial concentration profiles in a packed-bed membrane reactor and the local velocity field while accounting for the influences due to the distributive membrane flow and the radial porosity profile. The effect of the radial porosity profile on the model results has been evaluated for cases with a low tube-to-particle diameter ratio (d t/d p) with insufficient radial transport resulting in strong radial oxygen concentration profiles. From these calculations, it was concluded that the overall effect of the porosity profile on the conversion−selectivity plot is unexpectedly small. If the implementation of a radial porosity profile is not required by other considerations, e.g., for an accurate description of temperature effects, then the effect of the porosity profile can safely be neglected. If a radial porosity profile is implemented, however, the effect of the porosity profile on the dispersion coefficient should be taken into account to achieve a proper description of the radial transport.