Modeling of absorbed radiation profiles in a system composed by a plane photoreactor and a single lamp

Ultraviolet irradiation constitutes an alternative to thermal treatment that is being studied and developed to obtain a better final product sensory quality, but without neglecting microbial safety. In order to quantify and predict chemical changes produced by ultraviolet radiation in a food system and to infer essential information for reactors design, a concrete modeling is required in each case, since the absorbed amount of radiation has a definitive effect on the reaction rate of the process in each point of the reaction medium depending on its location. Although the basic equations were set decades ago, there are still several concrete cases whose three-dimensional modeling cannot be found in literature. In this piece of work, the linear spherical emission model has been applied to a system composed by a plane photoreactor and a single lamp, obtaining different profiles that show how radiation is absorbed as a function of the position inside the reactor and the absorbance of the reaction medium.

► Linear spherical emission model has been applied.
► Radiation penetration profiles were calculated as a function of medium absorbance.
► If μ = 0.1, hardly a 30% of the emitted radiation is absorbed in 2.4 cm depth.
► If μ = 5 the whole radiation is absorbed in the first cm.