Utilization of pressurized CO2, pressurized ethanol and CO2-expanded ethanol mixtures for de-oiling spent bleaching earths

Publication date: Available online 25 March 2019Source: The Journal of Supercritical FluidsAuthor(s): P. Subra-Paternault, C. Harscoat-Schiavo, R. Savoire, M. Brun, J. Velasco, V. Ruiz-MendezAbstractCompressed fluids were used in a two-step scheme to extract oil from rapeseed and sunflower spent bleaching earths. The first extraction, performed with CO2 at 45 °C, 23 MPa, yielded matrices depleted in neutral lipids (contents of 1% and 3.5% compared to initial 22% and 28%) and of better flowing characteristics thanks to the downsizing of particle (83% of particles had sizes below 50 μm). The second step was assisted by ethanol used either as a compressed liquid, as a co-solvent or as a CO2-expanded mixture by changing temperature (35°, 60 °C) pressure (6, 18 MPa) and ethanol percentage (10 – 100 wt%). A statistical analysis concluded that extraction yield and oligomers percentage were dependent on pressure, ethanol percentage and their interaction, whilst temperature was a significant factor only for yield. The pigments content of oils produced by CO2 and extracts produced by pressurized ethanol was below 5 μg/goil and 32 mg/gextract.Graphical abstract
Source: The Journal of Supercritical Fluids - Category: Chemistry Source Type: research