"Scaling-up of a Homogeneous Photoreactor"

M. LABAS, C. ZALAZAR, R. BRANDI, C. MARTÍN Y A. CASSANO

Karlsruhe (Alemania)

Conferencia; Updates in Photochemical Technologies; 2001

One of the most powerful methods for designing a commercial scale photoreactor is the use of rigorous mathematical modeling. When this procedure is properly used, in many cases it is possible to move directly from the laboratory to the larger scale avoiding costly and time consuming intermediate steps.  Advanced oxidation technologies are not an exception and developing method for scaling-up and design should greatly improve the spreading of many of these new processes employed for air and water pollution treatment.Radiation field non uniformities are irreducible. Thus, the only way to extrapolate results from the laboratory scale to any other reactor size is by modeling both, the small and the large reactor. Using formic acid as a model compound, the decomposition reaction employing hydrogen peroxide and UV radiation has been modeled in two different scales: a small laboratory scale (photoreactor volume = 65 cm3) and larger scale (a 2.0 meters long, annular photoreactor, in two separate stages, having a cross sectional area of 65 cm2). The small reactor was used to obtain an intrinsic kinetic expression for the decomposition reaction. The larger one was used to validate model predictions with new, additional experiments. Coupled mass and radiation balances are always needed. Under non-isothermal conditions, the thermal energy balance is also required. The hydrogen peroxide process is homogeneous and hence no scattering will be present.