Comparative study of interval highly activated drying versus continue and intermittent convection drying processes

Conventional airflow is the most widely used drying process, although it has several drawbacks that affect the performance and quality of the final product. Investigators have operated various innovative drying techniques to improve the process's efficiency and the product's quality. For several years, our research team has defined new intensification drying processes such as swell drying (including Instant Controlled Pressure Drop (DIC)), Multi-Flash Autovaporization (DDS), and other intermittent drying processes. These operations, generally based on interrupting product exposure to heat, can improve energy efficiency and product quality. They have solved some of the problems of conventional continuous drying, such as long time, high-energy consumption, surface hardening, shrinkage, and poor-quality attributes. However, the definition of active and tempering periods in conventional intermittent drying has been empirical due to the lack of fundamental studies. Recently, we defined highly activated interval drying operations as an innovative drying process that intensifies drying performance and improves the quality of finished products. It aims to ideally separate the transfer phenomena during drying, exclusively dedicating the active period (tON) to surface evaporation and the tempering period (tOFF) to the diffusion of water within the product.