褐煤干燥特性的实验研究  

Experimental study on drying characteristics of lignite

作　　者：熊程程[1,2] 向飞[2] 吕清刚[2] 

机构地区：[1]中国科学院研究生院,北京100049 [2]中国科学院工程热物理研究所,北京100190

出　　处：《化学工程》2011年第8期74-78,共5页Chemical Engineering(China)

摘　　要：为获得褐煤颗粒干燥器设计的基础数据,对宁夏褐煤进行了工业分析、热重分析,得到了褐煤水分、挥发分的质量分数,确定了宁夏褐煤干燥的温度范围。褐煤的热重分析表明:褐煤干燥温度应不高于250℃。在热重分析确定的温度范围内,采用薄层干燥方式进行了褐煤颗粒的等温干燥实验,获得了褐煤颗粒干燥速率随水分的变化关系,颗粒的干燥主要处于降速干燥阶段,干燥过程中未出现恒速干燥阶段,说明褐煤颗粒的干燥主要受扩散机理控制;对实验结果进行动力学分析,整理出在80—120℃下干燥的有效水分扩散系数变化范围为5.91×10-8—1.815×10-7m2/s。根据Arrhenius经验公式建立了温度与扩散系数的关系,得到干燥时水分扩散活化能为32.44 kJ/mol。In order to design a lignite dryer, the proximate and thermo-gravimetric analysis of Ningxia lignite were carried out and the constant-temperature drying characteristics were studied. The relative mass fraction of water and volatilization in lignite was obtained from thermo-gravimetric analysis, showing that the temperature for operation should be lower than 250 ℃. According to the constant-temperature drying experiments, there is not constant-rate drying period for lignite and the drying rate is mainly controlled by water diffusion. The effective moisture diffusion coefficient is varied from 5. 912 × 10 ^-8 to 1. 815 × 10 ^-7 mE/s at 80-120 ℃. Based on Arrhenius type equation, the relationship between the effective diffusion coefficient and temperature was established, finding that the activation energy for moisture diffusion of lignite drying is 32.44 kJ/mol.

关 键 词：褐煤 热重分析 有效水分扩散系数 干燥 活化能 

分 类 号：TQ533.2[化学工程—煤化学工程]