Numerical study of different particle size distribution for modeling of solid-liquid extraction in randomly packed beds

• Using Montan wax extraction as a study case, solid-liquid extraction process is modeled.
• A new scheme is proposed to reduce the 3D model of the random packing into a 2D model.
• Impacts of particle size distributions of the solid phase on the extraction kinetics and the extraction rates are studied.

In this paper, the Montan wax extraction as an industrial example for a solid-liquid extraction process is modeled and simulated using 2D and 3D CFD models. Carrying out various simulation studies, the applied particle size distribution of the solid phase is studied concerning its impact on the extraction kinetics and the extraction rates. In the modeling, the solid phase, which is a wax-containing brown coal, is described by establishing 2D models of random packing in cylindrically packed beds. In the study, the applicability of a 2D CFD model is validated against simulation result of a 3D model of a random packing. The random packing of the 2D model considers the same mean particle size with a uniform distribution and a normal distribution, respectively. The simulation result indicates that the extraction rate is greatly increased using the brown coal of a normal particle size distribution, which is a good match with experimental results.