화학공학소재연구정보센터
Journal of Supercritical Fluids, Vol.149, 42-53, 2019
Utilization of pressurized CO2, pressurized ethanol and CO2-expanded ethanol mixtures for de-oiling spent bleaching earths
Compressed 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 degrees 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 mu m). 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 degrees, 60 degrees 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 mu g/g(oil) and 32 mg/g(extract). (C) 2019 Elsevier B.V. All rights reserved.