DRYING RATE AND SHRINKAGE EFFECT INTERACTION DURING FREEZE-DRYING IN AN ADSORBENT MEDIUM

A Kinetic analysis of freeze drying by immersion in an adsorbent fluid ised bed process has been carried out in this paper. The process is de scribed based on a uniformly retreating ice front model in spherical g eometry. The model needs to know both temmperature and pressure drivin g forces, correlated as a function of water content. The influence exe rted by operational conditions on the heat and mass coefficients has b een studied. Transport coefficients are correlated as a function of th e operating conditions to obtain equations that can be used for predic ting purposes in fluid bed freeze drying. Kinetic aspects are related to quality indicators determined through shrinkage of product to selec t the most adequate operating conditions.