Investigation On Isopropyl Alcohol As An Oil Extraction Solvent

The research was conducted for the processing technology and energy recycling to evaluate isopropyl alcohol as an alternative of hexane for extraction soybean, peanut and cottonseed oils. The object was to extract high quality oil and meal by isopropyl alcohol at low costs and high safety. The quality of oil and meal of isopropyl alcohol extraction were compared with those of hexane. The soy oil extracted by isopropyl alcohol comprised 0.1% lecithin, 0.09% free fatty acid, the Protein Dispersion Index (PDI) of soy meal was 61; the hexane extracted soy oil comprised 2.1% lecithin, 0.7% free fatty acid, the PDI of soy meal was 14. The cotton seed oil extracted by isopropyl alcohol did not comprised free cotton hydroxybenzene and aflatoxin, there were 0.013% free cotton hydroxybenzene and 0.0002% aflatoxin in the meal. The peanut oil extracted by isopropyl alcohol comprised 0.45% free fatty acid, the meal comprised 3% water, 3.4% oil, 43.1% protein and 6.5% ash. The oil and meal quality of isopropyl alcohol extracted were better than hexane extracted. The solvent ratio would be 2.5 1, if the extraction condition was the same as hexane, which needed 5 times energy to recycle the isopropyl alcohol. For detracted the solvent ratio and energy for recycling the solvent, the expanding, chilling separating miscella, recycling tip-phase and the membrane filtration. The resulted ratio was 1:1. 3 By membrane filtration isopropyl alcohol was concentrated to more than 93% at acceptable costs. 865.2kj energy was needed to evaporate 1 kg 87.7% isopropyl alcohol water azeotrope, only 43.26kj was needed for chilling, equivalent to 5% of that of evaporation. Plus the expense of drying collets to 3.5% moisture before extraction, 22% energy was saved by used chilling separation and membrane filtration. isopropyl alcohol was not prone to fire and explosion compared with hexane. Better qualities of oil and meal were resulted by isopropyl alcohol extraction. Base on the expanding, chilling separation, recycling up-phase and membrane filtration, isopropyl alcohol is feasible as a replacement solvent for hexane.