微波辅助萃取过程中有效成分扩散的动力学特征  

Kinetic Characteristics of Effective Composition Diffusion in Microwave-Assisted Extraction

作　　者：郭平生[1] 刘海力[1] 

机构地区：[1]广西师范大学物理与电子工程学院,广西桂林541004

出　　处：《高校化学工程学报》2009年第5期780-785,共6页Journal of Chemical Engineering of Chinese Universities

基　　金：973国家重点基础研究发展规划项目资助(G2000026307)

摘　　要：为研究微波条件下萃取过程的动力学规律,从有效成分与微波场之间的相互作用出发,分析了有效成分在微波场中所获得的非热效应能,并在微波条件下建立有效成分扩散速率公式的基础上,分析讨论了微波辅助萃取中有效成分扩散的动力学特征。理论分析结果表明,对不同条件的萃取实验,有不同的萃取动力学特征,主要表现为在萃取时间内是否出现时间拐点。当存在时间拐点时,微波条件下动力学关系曲线为先上凹再上凸的特征形式;当不存在时间拐点时,动力学关系曲线为一致上凸的特征形式;先上凹再上凸的动力学特征形式是微波条件下特有的,是不同于传统萃取方法的动力学特征。通过对实验结果拟合表明:从理论上得到的扩散动力学特征与实验结果一致,验证了微波条件下扩散动力学特征有两种可能的理论分析.In order to study the kinetic law of the microwave-assisted extraction,the non-calorific energy obtained by the effective composition in microwave field was theoretically analyzed via the interaction between effective composition and microwave field,and the kinetic characters of the effective composition diffusion in microwave-assisted extraction was expatiated by establishing a practicable diffusion equation of the effective composition under microwave. The theoretical analysis results indicate that there are different parameters for different experiments,and they may determine whether the time inflexion point appears on the time course curve of the microwave-assisted extraction. When the time inflexion appears,the time course curves of kinetic relation under microwave are concave-convex,and the curves of kinetic relation are uniformly convex when the time inflexion does not appear even when the extraction is assisted by microwave. The kinetic relation curve has the form of concave-convex is the characteristic of the microwave-assisted extraction,which is the difference between the conventional extraction and microwave-assisted extraction. Via using the established equations,the results of experimental data fitting show that the theoretically yielded diffusion kinetic characters are in accordance with that of experiment results,and the theoretical analysis result of existing two possible diffusion kinetic characters under microwove-assistance is verified.

关 键 词：曲线上凹 曲线上凸 时间拐点 动力学特征 

分 类 号：O658.2[理学—分析化学] TQ021.4[理学—化学]