李善莲，王宏生，袁行思
（中国烟草总公司郑州烟草研究院，郑州市高新技术开发区枫杨街2号 450001）
摘 要：采用下进风方式的热风对流干燥方法，对烤烟和白肋烟在不同热风温湿度下的干燥过程进行了实验研究。深入地研究了干燥过程中烟叶平均含水率和表面温度随时间的变化规律。绘制出了实验烟叶的干燥特性曲线；找出了干燥过程中烟叶平均含水率和表面温度随时间变化的数学方程。实验结果表明：①实验烟叶的干燥特性曲线可以大致地分为三个干燥阶段，干燥较快的第一干燥阶段，干燥非常慢的第三干燥阶段，以及由干燥较快向非常慢过渡的第二干燥阶段。②实验烟叶在实验条件下的平均含水率随时间的变化规律可用 （X烟叶平均含水率，Xe平衡含水率，t干燥时间，A、K实验常数）来描述，并且烟叶平均含水率的变化随着热风温度的提高或热风湿度的减小而加快。③烟叶表面温度随时间的变化规律可用 (T烟叶表面温度，Ta热风温度，t干燥时间，A1、A2、K、K1实验常数)来描述，并且烟叶表面温度的上升随着热风温度的提高或热风湿度的增大而加快。实验结果将有助于优化、改进烟叶复烤的工艺参数和提高白肋烟的处理质量，有助于烟叶精细化加工的深入研究。
关键词：烟叶；干燥；特性；含水率；温度
　 Experimental studies on the properties of tobacco under convective drying
LI SHAN-LIAN， WANG HONG-SHENG， and YUAN XING-SI
（Zhengzhou Tobacco Research Institute of CNTC， Zhengzhou 450001 China）
Abstract: Under convective drying with upward hot air， experimental studies were conducted on flue cured and burley tobacco in a batch processing equipment. The mean moisture content and surface temperature of tobacco during drying were measured. As a result， drying characteristic curves for tobacco samples were plotted， and mathematical equations for mean moisture content and surface temperature of tobacco during drying were developed. Experimental results indicated that ①drying characteristic curves for tobacco samples could be divided into three main drying phases. The first drying phase features rapid variation of mean moisture content and surface temperature of tobacco samples; the third drying phase features very slow drying rate and surface temperature increase; And the second drying phase is virtually a transition phase from the rapid variation to the very slow variation. ②The variation of mean moisture content of tobacco during drying is accelerated by increasing the temperature or decreasing the humidity of hot air， and can be depicted by the follow equation: （Where，X is the mean moisture content of tobacco during drying，Xe is the equilibrium moisture content of tobacco，t is drying time，A and K are constant）. ③The increasing of surface temperature of tobacco during drying is accelerated by increasing the temperature or humidity of hot air，and can be depicted by the follow equation： (Where，T is the surface temperature of tobacco during drying， Ta is the temperature of hot air，t is drying time，A1，A2，K and K1 are constant).
Keywords: tobacco；drying；characteristic；moisture content；temperature
热风对流干燥是烟叶干燥中应用较为普遍的干燥方法[1]。烟叶热风对流干燥过程中，干燥介质——空气的温度和湿度是影响烟叶干燥特性的两个重要的外界因素，在一定的温、湿度条件下，通过对流换热，气流中的热焓传递给烟叶，使烟叶的含水率和温度发生变化，并伴随复杂的化学变化，其中烟叶含水率和温度的变化特性对烟叶干燥质量和工艺控制是非常重要的。根据文献调研发现[2~5]，以前较多的是研究干燥过程中烟叶含水率的变化，而对干燥过程中烟叶温度的变化研究较少。本文采用下进风方式的热风对流干燥方法，对烤烟和白肋烟在不同热风温、湿度条件下烟叶平均含水率和表面温度随时间的变化规律进行了深入的研究。
 

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