Scale-up and Modeling of Fixed-Bed Reactors for Catalytic Phenol Oxidation over Adsorptive Active Carbon

Abstract

The wet air oxidation of phenol over a commercial active carbon catalyst has been studied in laboratory and pilot plant Fixed Bed Reactors at mild temperatures and oxygen partial pressures of 120-160 ºC and 0.05-0.2 MPa, respectively. The performance of the Fixed Bed Reactors has been assessed and compared to each other for both up-and downflow operation mode. Depending on the flow mode and reactor scale, distinct phenol destruction rates have been observed in the experiments. A series of batch experiments are carried out to obtain phenol removal kinetics, which are subsequently implemented in the modelling of the pilot Fixed Bed Reactor. A one-dimensional non-isothermal Piston Dispersion model is developed to describe in detail the interplay of reaction kinetics, gas-liquid hydrodynamics and heat and mass transfer in both flow directions. The model predicts reasonably well the experimental data, thus allowing for a thorough explanation of the observed pilot reactor performance.