| Due to the health problem of the current extraction solvent hexane to the human andhazardous pollution to the environment there is more and more interest among many countries inmore appropriate solvent and novel extraction technologies. And this work has been developedwell. By comparing of different solvents isopropyl alcohol (IPA) was determined to be the bestsolvent instead of hexane in this study. IPA has strong solubility of phospholipid, free fatty acidsand pigments and it is easy to be separated from miscella and be reclaimed with the chillingseparation method. Meanwhile it has lower energy cost and is adapted to the currently usedequipments.By the study of the two extraction technologies pervaporation membrane separation methodand chilling separation method the best extraction stage number, extraction temperature,solvent/collet ratio, oil content of miscella and pretreatment method were determined. Based on theoil solubility in the solvent IPA and the characteristics of miscella temperature the reclaimingprocessing technology of the solvent, the reclaiming method and corresponding technologyparameters were determined. By the study of the concentration of IPA and miscellas, the influenceof the temperature on the separation of the upper and lower phases the impact of the change ofdifferent oil content in the upper and lower phases on the concentrate of free fatty acids andphospholipid during chilling separation process was discussed.In this study the kinetics characteristic of oil extraction process was studied and themathematical models of oil extraction rate were developed based on the regression ofexperimental data. The oil extraction processes were simulated with the software Matlab andPro/E. With the simulation results the impacts of some extraction parameters such as temperature,pretreatment method, solvent/collet ratio and water content on the extraction rate were discussedand the relationship between the extraction rate and the oil diffusion coefficient was decided.Based on all the analysis the glass extraction apparatus and pilot experimental virtual equipmentswere designed.The quality of oil and meal of IPA extraction were compared with those of hexane. The soyoil extracted by IPA comprised of 0.1% phospholipid, 0.09% free fatty acid and the ProteinDispersion Index (PDI) of soy meal was 61. The hexane extracted soy oil comprised of 2.1%phospholipid, 0.7% free fatty acid and the PDI of soy meal was 14.The qualities of oil and meal extracted by IPA were better than those of hexane extracted. Thesolvent ratio would be 2.5:1 if the extraction conditions were the same and the latent heat ofevaporation of 95% IPA is about 2.2 times of that of commercial hexane. For decreasing thesolvent ratio and the energy for reclaiming the solvent, the expanding pretreatment, chillingseparation, recycling the upper phase of miscellas and reclaiming of IPA with the pervaporationmembrane were used in this study. With the above methods the solvent ratio reached 1:1 and IPAwas rectified to 93% concentration.It was about 865.2kj needed for evaporating 1kg 87.7% IPA. It was only about 43.26kj neededfor chilling of 1kg 87.7% IPA which was equivalent to 5% energy of that for evaporation. Whenthe energy for chilling and the energy expense for drying collets to 3.5% moisture content beforeextraction were added together 22% energy was saved by using chilling separation method andthen reclaiming the solvent with pervaporation membrane.IPA is less flammable than hexane,and extracts of crude oils and meal are equal to or betterthan those obtained with hexane extraction.It was feasible of the solvent IPA instead of hexanewith the extraction technology using the expanding pretreatment method, chilling separationmethod, recycling the upper phase of miscellas and reclaiming of IPA with the pervaporationmembrane method.
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