Modeling of PAH Elimination by Adiabatic Steam Stripping and Intraparticle Desorption

Abstract

The decontamination process of solids loaded with PAH in a pilot plant is modeled. This process is separated into two main stages: fast steam stripping at the entrance of the separation tube and the subsequent slow desorption of PAH from the interior of the soil particles. The stripping process also occurs in two stages: fast diffusion controlled saturation of the partial pressures followed by the heat transfer controlled evaporation. The phase diagram of PAH/water is constructed using both the microscopic model and empirical relationships for systems with wide miscibility gaps. The numerical basis for the calculations describing desorption from the soil particles is discussed. The model for multiple PAH components is based on Langmuir type isotherms which include surface diffusion terms. The obtained results are contrasted with analytical data for systems displaying linear isotherms by dispersive approximation.