Supercritical fluid extraction Liquid carbon dioxide, with a purity of 99%, was acquired from
WhiteMartins. The experimental apparatus usedin this work is shown in Fig. 1. It consisted of a 50mL equilibrium
cell (7) immersed in a water bath controlled by a heater to within ±0.1 ◦C. The CO2 from the supply tank (1)
was cooled to the liquid state (2) and compressed into the extractor using a high-pressure pump (3). The gas flow
meter (10) was used by measuring the flow rate, the temperature and the pressure of CO2 as
ideal gas in the exit of system. The volume totalizer (11)was used tomeasure the total
volume of CO2 used in the extraction The other equipments used were: CO2 cylinder (4),manometers (5, 6), glass flasks (9) and a peristaltic pump (10) to clean the system. All experiments were carried out in triplicate. About 5×10−3 kg of sample were loaded into the extraction vessel and mesh six glass beads used to fill the
empty spaces in the vessel. A static period of 20 min was used to allow contact between the samples and the supercritical solvent.The amount of SC-CO2 was maintained constant at 400 L (0.650 kg
approximately) for all the experiments and the CO2 mass flow rate was maintained at 4×10−5 kg/s. After extraction, all the tubing at the end of the process linewaswashedwith n-hexane to recover the
extract deposited in it. To determine the global extraction yield (X0), the amount of oil that could be obtained in a single extraction was first calculated, and the ratio of the total mass of extract obtained
(extraction + cleaning process) to the initial mass of raw material then determined (dry basis) and multiplied by 100%.