褐煤干燥特性与动力学研究

Drying Characteristics and Kinetics of Lignite

褐煤粒径分布宽,成分多样,初始含水率多变,干燥特性复杂。考察了粒度、密度、初始含水率和温度对褐煤干燥特性的影响,得到了褐煤含水率随干燥时间的变化规律,建立了褐煤干燥动力学方程。结果表明:褐煤干燥经历快速干燥和慢速干燥两个阶段,干燥速率随密度和温度增大而增大,随粒度、初始含水率增大而减小;干燥动力学最佳模型为Page模型,模型常数与粒度、密度、初始含水率和温度有经验关系,方程能较好地预测干燥过程中褐煤的动态含水率。

Lignite has wide size distribution,diverse composition,variable initial moisture content and complex drying characteristics.In this paper,the effects of particle size,density,initial moisture content and temperature on the drying characteristics of lignite are investigated.The variation of moisture content of lignite with drying time was obtained.Based on the experimental data,the drying equation of lignite was established.The results show that lignite experiences two stages:fast drying and slow drying.The drying rate increases with the increase of particle density and temperature,and decreases with the increase of particle size and initial moisture content.The optimum drying kinetics model of lignite is Page model.Model constants have empirical relationships with particle size,density,initial moisture content and temperature.The equation can well predict the dynamic moisture content of lignite during drying process.