ATMOSPHERIC FREEZE-DRYING PART 2 : MODELLING DRYING KINETICS USING ADSORPTION ISOTHERMS

This paper describes the modelling of atmospheric pressure freeze-drying using a fluidized bed of adsorbent. The original feature of this modelling, based on a model of the “Uniformly Retreating Ice Front” type, is the coupling of the laws of heat and mass transfer as well as the introduction into the model of adsorbent sorption isotherms. The model which describes dehydration kinetics has been validated further to experiments on potatoes. The working parameters of the facility were optimized thanks to the model. This new freeze-drying process may well be useful for small freeze-dried products dried at a temperature close to their melting point.