摘要
在前段120℃后段90℃(120&90℃),110&80℃和100&70℃不同热风温度组合的变温干燥条件下,考察了烟丝含水率、温度等变化规律,并与恒温干燥结果进行了对比分析。结果表明:①变温干燥时,烟丝含水率及干燥速率变化曲线在变温点之前与高温热风条件下的恒温干燥曲线一致,在变温点之后则逐渐接近低温热风条件下的恒温干燥曲线,Midilli模型可较好对变温干燥动力学进行描述;②变温干燥时,烟丝干燥终点温度显著低于高温热风条件下恒温干燥终点温度;对不同变温干燥条件,在变温点附近均存在一烟丝表面温度相对稳定的脱水过程;③不同变温干燥条件下,烟丝填充值介于前后段温度热风恒温干燥之间。前段100℃后段70℃的变温干燥试验条件下,烟丝填充值则相对接近于100℃热风恒温干燥结果。
The change of moisture content in and temperature of cut tobacco during variable temperature drying were determined at different hot air temperature C0mbinatons of first section at 120 ℃ and second section at 90 ℃(120&90 ℃), ll0&80 ℃ and 100&70 ℃, the determined results were analyzed and compared with those under constant temperature drying. The results showed that: 1) Under variable temperature drying, the variation curves of moisture content and drying rate of tobacco before temperature changing were consistent with those under constant temperature drying at high temperature (100, 110 and 120 ℃); after temperature changing, the curves gradually approached to those of constant temperature drying at low temperature (70, 80 and 90 ℃). The dynamics of variable temperature drying could be described by the Midilli model. 2) For variable temperature drying, the end temperature of cut tobacco was significantly lower than that of constant temperature drying at high temperature, and there existed a dehydration process at a relatively constant tobacco surface temperaturearound the point of temperature changing. 3) The filling value of cut tobacco dried at different temperature combination was between that dried at high and low constant temperatures. However, the filling value of cut tobacco dried at 100&70 ℃ was close to that dried at the constant temperature of 100 ℃.
出处
《烟草科技》
EI
CAS
北大核心
2014年第4期20-25,共6页
Tobacco Science & Technology
基金
国家自然科学基金“植物多孔介质快速干燥过程微细结构变化的分形特征及对热质传递影响机制”(51306213)
中式卷烟制丝专线重大专项“分段式变温干燥机理及品牌应用技术研究”[110201201015(ZS-01)]
关键词
烟丝
变温干燥
恒温干燥
含水率
Cut tobacco
Variable temperature drying
Constant temperature drying
Moisture content