(532dy) Reactive CFD and NMR: Bringing research areas together for detailed, full-field validation

In the course of the last decade, multiscale modeling attracted considerable research interest in the chemical engineering community. Combining chemical reactions with high-resolution Computational Fluid Dynamics (CFD) can give new insights into phenomena within catalytic reactors, essential for Power-to-X technologies. These insights can be used to further optimize process parameters and reactor designs to increase the process efficiency.

Such multiscale simulations, however, are very complex. The employed models and reaction kinetics make proper validation all the more indispensable. So how do we achieve an appropriate validation? By now, integral as well as local methods are state-of-the-art. This includes measurements of gas compositions downstream of the reactor, through a capillary in the catalytic bed or temperature measurements using thermocouples. Besides most of them being invasive, these methods also do not represent the high spatial-resolution of CFD.

To fill this gap, the usage of Nuclear Magnetic Resonance (NMR) tomography is a promising approach. We already showed the feasibility of cross-validation between three-dimensional, gas-phase velocimetry measurements and CFD simulations in an Open Cell Foam (OCF) reactor. Despite the high complexity of the OCF, a good agreement of NMR tomography and CFD results was obtained with deviations below 10% in most of the cases. As a next step, the validation of a reactive setup is proposed, where the comparison of temperature as well as concentration data is at focus. For this, the heterogeneously catalyzed ethylene hydrogenation reaction on Pt/Al₂O₃ is simulated using kinetic expressions from literature. Besides a simple plate setup, we propose a new, additively manufactured reactor design consisting of a Periodic Open Cell Structure (POCS) with hollow struts for temperature measurements. These results shall be used to assess the opportunities of the combination of CFD and NMR to gain deeper insights into processes within catalytic reactors, the basis for further reactor optimizations.