Catalytic Ethane Dehydrogenation Using a Porcupine Heating Element in a Joule-Heated Reactor

A Joule-heated reactor containing a porous catalyst film deposited on a FeCrAl porcupine coil as the heating element was assembled and evaluated. The catalytic ethane dehydrogenation reaction was investigated utilizing a ZSM-5-supported MnOx catalyst. The system achieved an ethylene production rate of 31.3 mmolC2H4 gcat–1 h–1 with an ethylene selectivity exceeding 99% and 98 + % carbon balance and has a larger volumetric catalyst inventory than other Joule-heated reactor configurations reported to date. Despite ample insulation, computational fluid dynamics (CFD) simulations using ANSYS-CFX revealed axial and radial temperature gradients within the reactor, reducing the catalyst utilization effectiveness. The simulations demonstrate that adiabatic operation (perfect insulation and reflecting radiative heat back into the system) could double the ethylene production rate while improving energy efficiency. Mass and heat transfer resistances did not affect rates for catalyst layer thicknesses up to 135 μm. Analysis of the flow pattern revealed that buoyancy effects are significant at low inlet gas velocities (υin = 0.53 cm s–1 or Reinlet = 1.7), leading to reverse flows near the front and back coil terminals. These insights provide a foundation for optimizing Joule-heated reactor geometry, configuration, and performance.