Non-Isothermal Compressible Flow Model for Analyzing the Effect of High CO₂ Inlet Flow Rate on Particle Size in a Supercritical Antisolvent Process

Abstract

In this work with CFD simulations, the evaluation of the supercritical anti-solvent (SAS) process for producing nanoparticles from an expanded solution of ethanol/solute in carbon dioxide is reported. The influence of the solution and antisolvent flow rates on mean particle size, the flow dynamic, and the supercritical mixture's jet velocity must be well established in the literature and analyzed. The high flow rate of the anti-solvent resulted in increased mean particle sizes for all studied cases. At the lowest flow rate of CO₂ examined, an increase in the solvent flow rate [0.3-1.0] ml/min initially led to a decrease of 11.2% in the mean particle diameter (MPD); however, further increasing the solvent flow rate [1.0-2.0]ml/min was an increase of 33% in this parameter. At the highest CO₂ flow rate, the behavior of MPS was the opposite; it had a rise de 13.5% in MPD with an increase in solvent flow rate; further increasing the flow rate of the solvent, there was a drop of 8.6% in MPD. Significant variations in the temperature lead to large fluctuations in the particle diameters. At last, the contact zones between CO₂ and ethanol were delimited, favoring the understanding of the influence of the flow patterns generated by the variation of the flow rates in the mean particle diameters.