Process intensification and process control in freeze-drying

Abstract

[EN] Widespread use of advanced process control allows reduction of costs, by reducing drying time and energy consumption. The “control of the freezing stage” (by forced nucleation) also appears to be beneficial to process intensification, as it can impact the product structure and modify the product resistance to mass transfer. An alternative way to increase the drying rate is the use of organic solvents as they can lead to larger solvent crystals, hence lower product resistance to vapor flow. Atmospheric freeze-drying may be a good alternative to vacuum freeze-drying, as a way of increasing process efficiency. A further improvement can be obtained by combining atmospheric or vacuum freeze-drying with new technologies. A further step towards process intensification is given by continuous plants, as this allows a dramatic increase in throughput and product quality uniformity.