A complete 3D simulation of a crystallization process induced by supercritical CO2 to predict particle size

Crystallization induced by compressed CO2 is a process that operates under several MPa of pressure. By rendering on-line measurements very difficult to perform, simulation appears as a suitable tool to better identify the important parameters of the process. A mathematical model is developed in the case of a spray-crystallization process in which a solution of minocycline-ethanol is injected into carbon dioxide as antisolvent. The model accounts for the main physical phenomena involved, i.e. hydrodynamics, mass transfer, phase equilibrium, crystallization kinetics. Simulations are performed in 3D with a special insight in turbulence modeling. Numerical results are compared with experimental data from literature. Although experimental and simulated PSD fit satisfactorily, results emphasize the major role of the crystal–fluid interfacial tension on the accuracy. Numerical investigations are further performed to highlight the effects of injection velocity and solution concentration on the spatial distribution of the important variables in crystallization.

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► Coupling a population balance equation with a 3D CFD code in supercritical fluid.
► High velocity and high concentration favor the production of smaller particles.
► Solid–fluid interfacial tension has a major role on the accuracy of the simulation.