Instant Controlled Pressure Drop technology: From a new fundamental approach of instantaneous transitory thermodynamics to large industrial applications on high performance–high controlled quality unit operations

Solvent extraction processes have been largely used in various industries. They recently were improved through new physical concepts such as CO₂ Supercritical Fluid Extraction, Ultrasound assisted process, Microwave-assisted extraction, Instant Controlled Pressure Drop DIC-assisted extraction… Systematically, a pretreatment stage of grinding takes place in order to improve the exchange surface increasing the starting accessibility. Swelling of the material structure implies an increase of the porosity thus leading to higher solvent diffusivity within the solid matrix. A new concept of expanded granule powder has recently been defined using Instant Controlled Pressure Drop DIC technology. Whatever the type of solvent is (even CO₂-SFE), such a swelled structure dramatically intensifies the kinetics through a higher specific exchange surface thanks to the open pores, while improving the solution solvent–solute diffusivity within the solid. Coupled to ultrasound, the internal transfer of solute within the pore solvent can likewise be intensified by replacing molecular diffusion within the pores by an effective convection transfer. In this work, we carried out a first approach of modeling of solvent extraction kinetics of expanded granules involving higher exchange surface and greater internal diffusion process.