Comparison of the Prediction of the Temperature Profile in an Ohmic Reactor on Different Modeling Scales

To predict the temperature profile in an ohmic reactor, it is essential to know the thermal and electrical conductivity of the reactor geometry. Those properties can be considered on different modeling scales: On the detailed (resolved) scale, the reactor consists of a packed bed structure, where the properties of each substance are considered. On the effective (continuum) scale, the packed bed is considered as effective medium with composite properties. In this contribution, we consider both scales and compare the results. Based on the detailed description with a resolved microstructure, the bed's effective thermal and electrical conductivity are computed. These properties are compared with analytical formulas. The electrical conductivity is the basis for the electrical field and the current density. Finally, these properties are used to evaluate the ohmic heating of the packed bed exposed to flow and to compute the temperature distribution within the reactor.