MATHEMATICAL MODELING OF PARTICLE MCRONIZATION BY RAPID EXPANSION OF SUPERCRITICAL SOLUTIONS (RESS)

In this work hydrodynamic of the supercritical free jet in the rapid expansion of supercritical solution (RESS) process was modeled by solving simultaneously mass, momentum and energy balances. The model was used to study the effects of operating parameters on the produced particle size distribution considering the homogeneous nucleation, condensation and coagulation. In the RESS process, particles are formed by homogeneous nucleation simultaneously with particle growth via condensation of solute molecules on the external surface of each existing nuclei. The results show that the coagulation is the predominant mechanism in the sections below mach disk in the expansion device. A relatively good agreement between the experimental data and the estimation results is observed. Moreover the effects of extraction conditions on the particle size distribution were studied by the proposed model.

Keywords:

rapid expansion of supercritical fluid , micronization , modeling