Residence time distribution analysis and kinetic study of toluene photo-degradation using a continuous immobilized photoreactor

Abstract

The photocatalytic degradation of volatile organic compounds is an innovative intensification technology. In this study, photocatalytic degradation of toluene has been investigated in a novel continuous immobilized photoreactor and the flow regimes were characterized and modeled by means of residence time distribution (RTD) of the gas phase. RTD analysis indicates that the flow regime in such a reactor cannot be considered as perfect plug and that a significant axial dispersion is available. A compartment model consisting of fourteen continuous stirred tank reactors was assigned to describe the flow pattern in the reactor. A Langmuir–Hinshelwood (L–H) kinetics scheme has been used to describe the degradation of toluene to model the behavior of the reaction system. A number of different assumptions were made, i.e. the perfect plug flow model, the plug-flow with axial dispersion model and the continuous stirred tank reactors in series model. A comparison was made between the sum of the square errors (SSE) for experimental and predicted degradation ratios for each flow model revealing that continuous stirred tank reactors in series were a better description for the photocatalytic degradation of toluene.