Homogeneous and heterogeneous Advanced Oxidation Processes. An embryonic step to move from laboratory scale to full size applications in just one jump

ALBERTO E. CASSANO; MARÍA DE LOS MILAGROS BALLARI; ORLANDO M. ALFANO

Jacksonville

Conferencia; The 18th International Conference on Advanced Oxidation Technologies for Treatment of Water, Air and Soil (AOT-18); 2012

Redox Technologies, Inc.

A general methodology to perform the design and scaling-up of homogeneous and heterogeneous photochemical reactors from first principles is presented, working with three applications to Advances Oxidation Technologies. The first example is taken from a system where it is only necessary to resort to a radiation model that used just two optical properties: the absorption and reflection coefficients of the employed catalyst (TiO2). The procedure is illustrated with catalytic wall reactors. The kinetics was obtained in a small flat plate reactor with a total reacting surface area of 81 cm2. It is then extrapolated to a complex apparatus made of three concentric annular cylindrical tubes with all their walls coated with the catalyst having a total reacting surface area of 5,209 cm2. The pollutant degraded was perchlroethylene in air. The second illustration concerns the degradation of an aqueous solution of formic acid employing H2O2 and UVC radiation. The kinetics and the reaction sequence were obtained in a laboratory batch reactor having a volume of 70 cm3. It was scaled-up to a continuous tubular reactor of annular cross section (A = 65 cm2) having a reaction length equal to 200 cm. In this case, the required optical property is the absorption coefficient of hydrogen peroxide. In the third case, the analysis of a typical slurry photocatalytic reactor is presented. Accordingly, the modeling of an annular reactor inside a recycle for the decomposition of trichloroethylene is described. In order to formulate the photochemical reaction rate properly, the radiative transfer equation applied to participating and reactive, homogeneous and heterogeneous media is presented. The described approach makes use of the most important tools for mathematical modeling of photoreactors, permitting the complete and rigorous utilization of this procedure. This precise methodology It is based in four necessary conditions: (i) to have a validated kinetic scheme, (ii) to have a validated, intrinsic reaction kinetic expression as a function of position and time, (iii) to use in both reactors the same spectral radiation output power distribution and (iv) to apply and correctly solve a rigorous mathematical model to both, the laboratory and the large scale reactor.