Innovative freeze-drying process based on self-heat recuperation technology

Abstract

Freeze drying is a drying technology that removes water from a target by sublimation of ice to vapor. Drying at low temperature and pressure (below the triple point) results in fewer physical and chemical changes to the dried products compared with the changes observed when using other drying technologies, leading to producing a high quality product. However, the weak point of freeze-drying technology is its large energy consumption. It is therefore necessary to reduce the energy required for the freeze-drying process and the energy costs of production so that this technology can be extended to the drying of other products. In this paper, a new energy-saving freeze-drying process based on the concept of self-heat recuperation technology was proposed. The energy required for the proposed process was compared with a conventional technique using a commercial process simulator. From the simulation results, more than 80% of the energy required for drying can be saved by using the proposed process.