中药材挥发油提取过程的传质动力学模型

Kinetic model for extraction process of volatile oil from traditional Chinese medicine

利用Fick第二扩散定律和膜模型理论,分别建立了内扩散控制和气膜扩散控制的传质速率模型,并以苍术挥发油的提取实验以及文献数据对模型进行检验。实验结果表明,苍术颗粒半径较大时,挥发油提取过程由内扩散控制,服从一级动力学方程;颗粒半径小于0.090mm时,出油速率由气膜扩散控制,出油量和时间呈正比。利用所建立的动力学模型对其他5种中药材的数据进行拟合,得到了与文献数据较为吻合的计算结果,表明该模型是可靠的,能反映实际提取情况,具有一定适用性。

Kinetic models for extraction process of volatile oil from traditional Chinese medicine are rarely studied at present; therefore, theoretical guidance to optimization of the process parameters is not enough. In this study, based on inner diffusion and gas film controlled diffusion, two new models were proposed by using Fiek＇s second law of diffusion. In order to evaluate the models, experiments for volatile oil extracted from Rhizoma atractylodis were carried out under different conditions. When the radii of particles were large, the process was controlled by inner diffusion and followed a first-order equation. When the radii were less than 0. 090 mm, the process was controlled by gas film diffusion and the volume of volatile oil extracted was proportional to time. The simulations on extraction processes of other traditional Chinese medicines were also investigated. The data of experiment well accorded with the kinetic equation. The kinetic model was feasible to describe the actual extraction process and it provided a theoretical reference for the extraction process of volatile oil from traditional Chinese medicine.