Monolithic Stirrer Reactors for the Sustainable Production of Dihydroxybenzenes over 3D Printed Fe/γ-Al2O3 Monoliths: Kinetic Modeling and CFD Simulation

Abstract

[EN] The aim of this work is to evaluate the performance of the stirring 3D Fe/AlO monolithic reactor in batch operation applied to the liquid-phase hydroxylation of phenol by hydrogen peroxide (HO ). An experimental and numerical investigation was carried out at the following operating conditions: C = 0.33 M, CO,0 = 0.33 M, T = 75–95C, P = 1 atm, ω = 200–500 rpm and W ~ 1.1 g. The kinetic model described the consumption of the HO by a zero-order power-law equation, while the phenol hydroxylation and catechol and hydroquinone production by Eley–Rideal model; the rate determining step was the reaction between the adsorbed HO, phenol in solution with two active sites involved. The 3D CFD model, coupling the conservation of mass, momentum and species together with the reaction kinetic equations, was experimentally validated. It demonstrated a laminar flow characterized by the presence of an annular zone located inside and surrounding the monoliths (u = 40–80 mm s ) and a central vortex with very low velocities (u = 3.5–8 mm s ). The simulation study showed the increasing phenol selectivity to dihydroxybenzenes by the reaction temperature, while the initial HO concentration mainly affects the phenol conversion.