Analysis of operating strategies in the production of special foods in vials by freeze drying

A finite element model (FEM) with axial symmetry conditions and isoparametric elements was applied to the freeze drying of special foods in vials. The model was verified by experiments using a methyl cellulose test material. The model was used to simulate and evaluate various heating strategies in freeze drying in order to reduce drying cycles and increase process efficiency. The effect of sublimation front temperature and freeze drying periods on the process duration was analysed.