Numerical Study of the Impact of the Solution Flow Rate in the Supercritical Antisolvent Process: a 3D Approach

Abstract

Processes for precipitation of micro and nanoparticles using CO₂ in supercritical state have proved to be an efficient way to process a large number of compounds from various fields, particularly in the pharmaceutical and food industry. In the face of experimental difficulties, the computer simulation appears as a useful tool to determine important parameters of the process. Using a three-dimensional mathematical model, it was studied the development of a jet of solution (ethanol and minocycline) expanded in pressurized carbon dioxide in order to interpret the process of development of regions of supersaturation of the solution. The commercial code ANSYS FLUENT was used to solve the model relating the impact of the flow of solution (1, 3 and 5 ml/min) in the mixing chamber of the precipitation process. The influence of turbulence in the flow dynamics was analyzed with the k-e and k-? models. Analysis of supersaturation profiles showed that by increasing the solution flow rate there is an increase in supersaturation and also occur more recirculation regions. So the conditions of injection of a given solution, considered in this work, determine distinct regions of nucleation and particle growth. These characteristics can be taken into account in the design of a chamber that offers conditions for the precipitation of small particle with fewer clusters.