Computational Insights into an Electrified, Washcoated Nonoxidative Propane Dehydrogenation Reactor

Electrified reactors can power endothermic reactions using renewable electricity, but design principles are lacking. Here, we model a nonoxidative propane dehydrogenation reactor featuring a Joule-heated nichrome V wall with an adjacent washcoated Pt-Zn/silicalite-1 catalyst layer. The transient pseudo-two-dimensional (2D) energy and species conservation equations are solved simultaneously using finite differences. We discuss design principles for the washcoat thickness and reactor inner radius, focusing on mass transfer limitations and washcoat isothermicity. Radial temperature uniformity is governed by the relative convective (to the gas) thermal resistance rather than the conductive solid layers. The axial temperature in the washcoat is significantly influenced by the Peclet number, with gas preheating contributing to a more uniform axial temperature profile. Upon powering on, the reactor reaches the steady state from ambient conditions in less than 10 min. We analytically estimate the steady-state reactor temperature and the time needed to reach the steady state under simplified conditions. The space–time yield and energy efficiency correlate with the applied electrical power and inlet gas flow rate. The propane conversion is maximized at long residence times and high power. The reactor’s small diameter leads to low energy efficiency. With 15 cm thick thermal insulation, 90% sensible heat recovery, and a maximum catalyst temperature of 700 °C, the reactor achieves 50% energy efficiency. A scale-out strategy is proposed to increase the energy efficiency.