Mathematical modeling of mass transfer in supercritical fluid extraction of patchouli oil

Patchouli oil is a high-value essential oil used in cosmetic, food, and pharmaceutical industries. In this work, supercritical fluid extraction of patchouli oil with various operating process parameters (pressure, temperature, flow rate, and particle size) were studied and the results were modeled using the broken and intact cell model (BICM). From the experimental studies, it was found that the extraction rate was improved at higher pressures and flow rates, where the mass transfer resistances in the liquid and solid phase were decreased; however, the increase in temperature had an inverse effect on extraction rate and mass transfer. In the case of particle size, a moderate size of 0.3 to 0.6 mm gave the optimal extraction rate. The BICM predictions showed good agreements with experimental data and gave valuable insights regarding the mass transfer mechanism of the extraction process, including mass transfer coefficients and extraction periods governed by convection and diffusion.