科研之友
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摘要
In this work, supercritical CO(2) extraction has been carried out on a traditional Chinese herb of Baizhu under pressure of 15-45 MPa, temperature of 40-60 degrees C, mean powder size of 0.167-0.675 mm, and extraction time of up to 180 min. The maximum extraction yield obtained in 5 h is about 6.76 x 10(-2) g per gram raw materials at 60 degrees C and 45 MPa. The extraction process is correlated by means of five different mathematical models. The evaluation of these models against experimental data shows that among these models the Sovova model performs the best with an overall average absolute relative deviation of 1.62%, followed by Crank and Naik models, finally the Barton and Martinez models. From the Sovova model, the mass transfer coefficient in solid or fluid are obtained and they are varying in the ranges of 4.02-6.14 x 10(-8) m/s and 0.88-2.87 x 10(-9) mis, respectively. These results suggest that solute diffusion in solid matrices and solute mass transfer in fluid are both important in affecting the supercritical CO(2) extraction process of Baizhu.
- 出版日期2011-8
- 单位天津商业大学
