Pressure drop may negatively impact supercritical CO2 extraction of citrus peel essential oils in an industrial-size extraction vessel

Abstract

We determined the effect of pressure drop (ΔP) in a 3.6-m tall vessel on the CO2 extraction of Citrus Peel Oil (CPO). We represented mass transfer using a linear-driving-force model and a pseudo-Sips’ desorption isotherm for CPO. A single microstructural factor (877) was estimated from literature data on CPO extraction at several extraction conditions. We simulated the effect of ΔP on CPO extraction at 50 °C varying particle diameter (0.5 ≤ dp ≤ 2 mm), bed porosity (0.20 ≤ ε ≤ 0.35), and inlet CO2 pressure (9 ≤ Pin ≤ 10 MPa) under incipient fluidization conditions. The negative effect of ΔP on CPO extraction increased markedly as dp or ε decreased, or as Pin increased, with a 1.8 time increase in extraction time as compared to isobaric conditions when using 4.54 kg s−1 m−2 of CO2 at 50 °C and 10 MPa (dp = 0.5 mm and ε = 0.30).