干燥介质温湿度条件对片烟干燥动力学特性的影响

Effects of Temperature and Humidity of Drying Medium on Drying Kinetics of Strips

为了考察干燥介质温湿度条件对片烟干燥过程的影响规律，获得表征水分迁移过程的有效扩散系数和活化能，利用烟草热湿特性在线分析装置对河南上、中部片烟干燥动力学特性进行实验研究，同时结合菲克第二定律，建立片烟水分迁移的动力学模型。结果表明：片烟干燥过程受扩散机理控制；所考察的两种片烟样品在实验范围内有效扩散系数为（1.91-8.63）×10-11 m2/s ，且随着干燥介质温度的增加和相对湿度的减小而增加；通过对传统的Arrhenius 公式进行湿度修正，获得了干燥介质温度和湿度对片烟干燥特性影响的数学模型。

In order to investigate the effects of temperature and relative humidity of drying medium on the strips drying process and obtain effective diffusion coefficient and activation energy which characterized the process of moisture migration, the drying kinetics characteristics of strips of upper and middle tobacco leaves from Henan were researched with an online tobacco heat-moisture property analyzing device. By Fick’s second law, a kinetic model for the moisture migration was established. The results showed that the drying process of strips was dominated by diffusion mechanism. Within the tested range, the effective diffusion coefficient of the tested samples ranged from 1.91×10-11 to 8.63×10-11 m2/s, which increased with the rise of the temperature or the decrease of relative humidity of the drying medium. The mathematical model of drying characteristics of strips influenced by the temperature and humidity of drying medium was obtained by correcting the humidity in Arrhenius formula.