Supporting data and methods for the multi-scale modelling of freeze-drying of microparticles in packed-beds

Abstract

A multi-scale approach can be used to simulate the drying behavior of microparticles in packed-bed. Data outcomes from discrete element method (DEM) and computational fluid dynamics (CFD) simulations can be used to estimate some relevant product characteristics, such as the porosity, tortuosity, voids in the bed and permeability which are required by the multi scale model. Data from DEM simulations are presented, with a particular focus on the influence of the model parameters, packing characteristics and inhomogeneities (wall effect and particles segregation); computational costs and scala bility are also considered. Data on the properties of packings as modeled at the macroscale are presented with regard to the thermal conductivity of gases in the Knudsen regime and effective properties of packed-beds modeled as a pseudo-homogeneous medium. A mathematical model of the freeze-drying of single microparticles and its outcomes are first presented. Data outcomes from the mathematical model at the macroscale concerning the drying behavior of microparticles in a tray and in a vial are then presented and can be used for process design. Some further data, with detailed interpretation and discussion of the presented data, can be found in the related research data article, “A multi-scale computational framework for modelling the freeze-drying of microparticles in packed-beds” (Capozzi et al., 2019). Keywords: Freeze-drying, Packed-bed, Lyophilization, DEM, CFD, Spray-freeze drying