Enhanced Fluid Dynamics in 3D Monolithic Reactors to Improve the Chemical Performance: Experimental and Numerical Investigation

Three-dimensional (3D) Fe/SiC monoliths with parallel interconnected channels and different cell geometries (square, troncoconical, and triangular) were manufactured by robocasting and used as catalytic reactors in hydroxylation of phenol using hydrogen peroxide to produce dihydroxybenzenes; the reaction was performed at C-phenol,C-0 = 0.33 M, C-phenol,C-0:C-H2O2,C-0 = 1:1 M, W-R = 3.7 g, T = 80-90 degrees C, and tau = 0-254 g(car).h.L-1 with water as a solvent. The values of the apparent kinetic rate constants demonstrated the superior performance of the triangular cell monoliths for hydrogen peroxide decomposition, phenol hydroxylation, and dihydroxybenzene production reactions. A computational fluid dynamic model was validated with the experimental results. It demonstrated that the triangular cell monoliths, with a lower channel hydraulic diameter and not-facing interconnections, provided a higher internal macrotortuosity that induced an oscillating flow of the liquid phase inside the channels, leading to an additional transverse flow between adjacent parallel channels. This behavior, not observed in the other two geometries, resulted in a better overall performance.

Automated summary

Three-dimensional (3D) Fe/SiC monoliths with different cell geometries (square, troncoconical, and triangular) were used as catalytic reactors in the hydroxylation of phenol using hydrogen peroxide. The triangular cell monoliths demonstrated superior performance in hydrogen peroxide decomposition, phenol hydroxylation, and dihydroxybenzene production reactions. A computational fluid dynamic model validated with experimental results showed that the triangular cell monoliths induced an oscillating flow of the liquid phase and additional transverse flow between adjacent parallel channels, resulting in better overall performance compared to other geometries.