Efficiency Evaluation in a Fixed-Bed Photocatalytic Reactor: Radiation Modeling Using the Monte Carlo Method

A. MANASSERO; M. L. SATUF; ORLANDO M. ALFANO

San Diego

Congreso; The 19th International Conference on Semiconductor Photocatalysis and Solar Energy Conversion (SPASEC-19); 2014

Photocatalytic slurry reactors with suspended TiO2 particles are the most common types of reactors employed for research purposes. However, for practical applications, reactors with immobilized catalyst are preferred: no separation of catalyst is needed, and they allow operation under continuous mode. The main drawback of immobilized systems is the low area- to- volume ratio, which generally leads to mass transfer limitations and low reaction rates. This disadvantage can be overcome by proper reactor design. Maximum utilization of radiation is crucial to obtain efficient configurations of reactors with immobilized catalyst. In this work, the radiation model of a photocatalytic reactor filled with TiO2 coated rings is presented. The efficiency of the reactor for the degradation of an endocrine disrupting compound, clofibric acid (CA), is evaluated under different operation conditions. Experimental runs were carried out in a cylindrical reactor irradiated from one side through a circular flat window. The reactor was filled with 5 ´ 5 mm glass rings coated with TiO2 P25 (Evonik). UV radiation was provided by a halogenated mercury lamp. Experiments were carried out employing glass rings with 1, 3 and 5 catalyst coatings, and different level of irradiation (100%, 62% and 30%). The performance of the reactor was assessed by the quantum efficiency parameter, which relates the moles of pollutant degraded per mol of absorbed photons in the reactor. The Monte Carlo method was applied to know the spatial distribution of radiation absorption in the reaction space. Highest efficiencies were obtained in the reactor containing rings with 3 catalyst coatings and under 62% irradiation level.