| The article determined the technical process of supercritical fluid extraction based on experimental research and optimized the extracted conditions of botanic seedoil .In this paper the mathematical model of supercritical fluid extraction were set up together with the principle of mass balance and analyzed the mass transfer process of supercritical fluid extraction. The following three aspects were discussed in this paper An experimental apparatus was set up for supercritical fluid extraction .The results of extraction for three natural products showed that the apparatus can get high yield and realize the continuously monitoring for extraction parameter such as pressure ,temperature and flowrate. The apparatus have much performance such as the measurable of parameter, easily monitoring and high extraction rate. In experimental study, the extraction of oil from natural oilseeds using supercritical carbon dioxide was investigated. The optimal extraction parameters were selected through the vertical experiment and contrast experiment. In this work, the extraction rate was analyzed as a function of the extraction pressure, temperature, fluid flowrate, particle size distribution and void fraction .A conclusion was formed on the basis of the experiment data that the fluid flowrate and the void fraction of the extraction bed had a crossover effect .Jn the case of the extraction pressure and temperature 4 4i~ effect ,a crossover effect was also observed. According to the experimental data, a model based on differential mass balances performed along the extraction bed was proposed. The model was simplified by means of a series of mathematical transforming and formed a analytical derivation. Finally, a computer simulation procedure based on the equation was programmed and analyzed the mass梩ransfer process of the supercritical fluid extraction. The equation of mass? transfer coefficient for the extraction process was: Sh = 0.24 Re073 Sc? (Re=O. 1?, Sc=3--30)... |
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