Fractionation of Edible Oil Model Mixtures by Supercritical Carbon Dioxide in a Packed Column. Part I:  Experimental Results

Abstract

The design of countercurrent packed columns operating under high-pressure conditions requires knowledge of their hydrodynamic and mass transfer behavior. A laboratory-scale continuous supercritical fluid extraction apparatus was developed with the purpose of obtaining data needed for such designs. The current work is part of a study to assess the feasibility of supercritical carbon dioxide in fractionating a mixture of squalene and methyl oleate. This mixture partly emulates the residues obtained from the olive oil refining process. Phase equilibrium data were previously measured to evaluate the best operating conditions. Here, we examine the continuous fractionation of two different feeds, with 40 and 70 wt % of squalene, under various extraction conditions. An extraction yield as high as 90 wt % of squalene in the raffinate phase was achieved.The selectivity and extraction efficiency were determined as functions of the oil-to-carbon dioxide flow ratio as well as the reflux ratio. In a subsequent paper (Part II), the measured hold-up and mass transfer coefficients will be compared with mass transfer correlations from the literature, and a model will be developed.

Dynamic model of a countercurrent packed column operating at high pressure conditions

“…The original apparatus is described in detail elsewhere [6]. The prime element of the apparatus is the high-pressure extraction column, with an internal diameter of 2.4 cm and 2.5 m height.…”

“…The vapour-liquid equilibrium of the ternary system methyl oleate/squalene/carbon dioxide was measured at several conditions of pressure, temperature and composition and reported elsewhere [5]. The mass transfer and the hydrodynamics of the fractionation of methyl oleate from squalene by supercritical carbon dioxide were studied at different operating conditions [6,7].…”

Fractionation technologies for liquid mixtures using dense carbon dioxide

“…The research group of Portugal at the Laboratório Associado para a Química Verde -Tecnologias e Processos Limpos (REQUIMTE) has operated their columns in both the stripping, and reflux mode of operation. REQUIMTE research is related mainly to edible oil components and derivatives: fractionation and de-acidification of olive oil deodorized distillates [12,44] and separation of squalene from methyl oleate [16]. Additionally, they have reported one work on wine must aroma [90] and have contributed with mass-transfer studies in packed columns [62,160], dynamic simulation of coupled mass and energy balances [109,153,161,162], and the use of Computer Fluid Dynamics (CFD) for pressure drop calculations [163,164].…”

“…Regarding the contact angles, Sutjiadi-Sia et al [243] observed increasing values at higher pressures, and the water mixtures showed better wettability (lower contact angles) on glass than on the other materials. M a n u s c r i p t 16 Based on these observations, Sutjiadi-Sia et al [243] concluded that when aqueous drops are desired in a spray column, it is advantageous to work with higher CO 2 pressures because the wetting becomes poorer (formation of small drops due to lower IFT). However, for such systems less liquid hold up is expected.…”

Supercritical carbon dioxide fractionation of the model mixture squalene/oleic acid in a membrane contactor

“…The SFE experiments were carried out in a continuous countercurrent packed column described elsewhere [13]. The high-pressure column (2.4 cm of internal diameter and 2 m high) is filled with Sulzer EX structured gauze packing.…”