2. RESS process

2.1 Principle

The RESS process involves dissolution-recrystallization. As shown in figure 2 , the solid of interest is dissolved in the FSC before being recrystallized by means of a sudden expansion through an expansion member.

In the supercritical range, a fluid is both dense and compressible. Density, which is related to solvent power, can vary greatly, depending on temperature (T ) and pressure (P ) conditions. If a solid can be dissolved in an FSC, it can then be recrystallized by simply expanding it through an orifice (circular hole, capillary or nozzle). The sharp, sudden drop in pressure, accompanied by a simultaneous drop in temperature, causes supersaturation...