CFD modelling of an immobilised photocatalytic reactor for phenol degradation.

Photocatalysis is an advanced oxidation process, which has been gaining attention as a sustainable technology for tackling pollution. Optimum design, fabrication and scaling up of novel photocatalytic reactors are faced with problems such as fabrication cost and numerous experimental trials for optimisation. Computational fluid dynamics (CFD), a computer simulation technique can ease the process of scaling up photocatalytic reactors. The current study focuses on CFD modelling of a serpentine flow path photocatalytic reactor with curved baffles for phenol degradation. The investigation compared different reactor configurations to finalise the optimum design with maximum removal efficiency. Initially, a simple cuboidal reactor was chosen with an efficiency of 27%. However, with a serpentine flow path being introduced, the reactor displayed an improved efficiency of 42%. The addition of baffles improved flow homogeneity and degradation efficiency. The investigation showed that serpentine flow increased the residence time and fluid mixing, while the curved baffles prevented flow channelisation, which enhanced the degradation efficiency. Efficiencies corresponding to different baffle types and geometry were also compared and the final reactor design chosen was a horizontal curved baffled serpentine flow reactor with a flow rate of 0.3 L/s and improved efficiency of 43.1% for a residence time of 18.44 s.