ETD

• DMO
• foams

The objective of this thesis is to establish a comprehensive multi-scale numerical framework and optimize the experimental architecture of a structured ceramic foam reactor applied to the catalytic hydrogenation of dimethyl oxalate to ethylene glycol over a Cu/SiO2 catalyst.
In the first phase of the study, the focus is directed toward kinetic modeling and localized microscopic transport phenomena within the catalyst washcoat layer. By coupling a Langmuir-Hinshelwood-Hougen-Watson kinetic mechanism with a 1-D steady-state reaction-diffusion model resolved in MATLAB, the Thiele modulus and the internal effectiveness factor were mapped as a continuous function of the washcoat thickness.
The resulting thickness-dependent efficiency parameters were subsequently upscaled and integrated into the material and energy balances of a macroscopic plug-flow reactor model.
Particular engineering emphasis was placed on the preparation and rheological optimization of the catalytic slurry, evaluating different slurry removal methods, to ensure a uniform washcoat distribution and eliminate pore clogging while precisely controlling the final layer thickness. Particular engineering emphasis was placed on modifying the rheological behavior of the catalytic formulation; specifically, the effects of two organic additives: polyvinyl alcohol and hydroxyethyl methyl cellulose, were systematically investigated to tune the slurry viscosity and optimize the subsequent deposition process, which was carried out utilizing an ultrasonic bath coating methodology. To assess the quality of the deposition, the resulting washcoat thickness and the relative mass increase of each individual foam substrate were quantitatively evaluated. Furthermore, optical microscopy was exploited to visually detect microstructural coating imperfections, providing a critical diagnostic screen for phenomena such as pore blocking, even versus uneven layer distribution, bare support zones lacking catalyst, and regions prone to catalyst detachment or delamination.
Finally, due to operational constraints and external logistical delays that restricted the available experimental dataset to preliminary screening campaigns, the scope was extended to an explicit test rig optimization study. Specifically, the phase-equilibrium challenges of the methanol solvent and DMO within the feeding and downstream lines were analyzed, allowing for the formulation of structural and fluid-dynamic modifications to the experimental layout. Ultimately, by bridging the experimental slurry preparation with the numerical model, this work delivers a predictive synthesis protocol. The alignment of the rheological formulation with the target catalyst thickness optimized by the MATLAB effectiveness factor maps provides an operational blueprint. This integration ensures that future experimental campaigns can maximize chemical throughput and minimize mass transfer penalties, establishing a robust foundation for the optimized operation of structured catalytic foam architectures.