Electrothermal digital twin: Radio frequency heating for propane dehydrogenation

In this work, we present a digital twin model for radio frequency (RF) heating of catalyst-coated monoliths for propane dehydrogenation (PDH). For our catalyst composition and RF-heated reactor design, a 3D finite-element method (FEM) model was developed to compute the resulting electromagnetic field, heat generation, temperature distribution, and propane conversion. These results are benchmarked against our experimental reactor data, where in a parallel plate capacitor was employed to heat a monolith-supported Pt/Alumina catalyst, with functionalized multiwalled carbon nanotubes serving as the RF susceptor. Through electromagnetic simulations, we were able to obtain the electric field profile of the applicator. Subsequently, we performed heat transfer simulations for the catalyst, which showed broad qualitative and quantitative agreement with our experimental heating data. Simulations show that heating rate of the catalyst is maximized at the frequency with lowest RF reflection. Additionally, the simulations indicate that the catalyst temperature exhibits a non-monotonic relationship with the electrical conductance of the catalyst coating, with the temperature reaching a maximum at conductance values of ~10 −4 S for our configuration. We modeled the kinetics of the endothermic PDH reaction coupled with heat transfer and electromagnetics; the simulations show propane conversions similar to our previously published experimental work for the RF-heated PDH reaction. Finally, we carry out a scale up analysis of RF heating of various sizes of catalyst-coated monolith in a parallel plate applicator. The results show that there is an optimal size at which the heating efficiency is highest. This work highlights the potential for employing electrothermal radio frequency heating of endothermic chemical reactions at industrial scales. • Digital twin model simulates the electric field, temperature, and concentration profiles in RF-heated catalytic reactors • Electric field distribution is sensitive to RF applicator and sample. • Heat transfer simulations show broad quantitative and qualitative agreement. • Propane conversions achieved in PDH reaction experiments are comparable with the simulation. • Scale up analysis shows the optimal size for best electrical efficiency and lowest power/volume