Temperature gradients within the packed bed affect cumulative supercritical CO2 extraction plots for oilseeds

We studied the effect of temperature gradients within a packed bed on the SuperCritical (SC) CO2 extraction of oil from pelletized cranberry seeds. Temperature gradients were imposed on the extractor by using different temperatures for the SC-CO2 flow and the extractor vessel wall in heating and cooling experiments (60 and 40 degrees C, and viceversa) for oilseed pellets and glass beads at 48 MPa. A two-phase heat transfer model and a linear-driving-force mass transfer model described temperature profiles and oil extraction curves. Overall, temperatures in the packed bed were more affected by the vessel wall than the SC-CO2 inlet condition. Extraction curves for heating and cooling experiments were between the isothermal extraction curves for 40 and 60 degrees C, being affected by the vessel wall temperature in the solubility-controlled period of the extraction and approaching each other after 1-h of dynamic extraction. Both heat and mass transfer models allowed a satisfactory prediction of such a behavior and represent a step forward in the prediction of SC-CO2 oil extraction course.

Automated summary

The study showed that temperature gradients within a packed bed have a significant impact on the extraction of oil from pelletized cranberry seeds using SuperCritical CO2. Experimental results were described using a two-phase heat transfer model and a linear-driving-force mass transfer model to predict temperature profiles and oil extraction curves accurately. This research represents a step forward in predicting the course of SC-CO2 oil extraction.