摘要
Ca（OH）_2/CaO体系是非常有前景的热化学储能介质,其动力学研究是了解整个储能体系的反应速率及能量储、释速率的重要途径.文中采用热重分析法,对Ca（OH）_2在氮气气氛、不同升温速率下的热分解过程进行了探究.结果表明,Ca（OH）_2样品分别在623.15-773.15 K和873.15-973.15 K出现两个分解失重过程,且失重率分别接近21%和2%.应用多重速率扫描法对热分解过程进行动力学分析,发现所得动力学参数与反应转化率、升温速率以及选用的模型方法有关.最概然机理函数分析表明,实验条件下,Ca（OH）_2热分解动力学模型符合相边界反应的收缩圆柱体模型.研究还发现,在不同升温速率下,指前因子的自然对数和活化能之间都存在着线性关系.
The Ca（OH）2/CaO system is a very promising thermochemical energy storage medium, and its kinetic research provides an important way of understanding the reaction and energy storage/release rates of the whole ener- gy storage system. In this paper, a thermogravimetric analysis is conducted to investigate the thermal decomposition processes of Ca（OH） 2 samples in pure N2 atmosphere at different heating rates. The results show that during the thermal decomposition of Ca（OH） 2 samples, two weight loss processes occur at 623.15 -773.15 K and 873.15 ~ 973.15 K, and the weight loss rates are close to 21% and 2% , respectively. The kinetic analysis of the thermal de- composition process through multiple scanning indicates that the obtained apparent kinetic parameters depend on the reaction conversion rate, the heating rate and the selected model approach. Through the most probable mechanism function analysis, it is also found that the thermal decomposition kinetics model of Ca （OH）2 under experimental conditions accords well with the shrinking cylinder mechanism with surface reaction rate controlling. Besides, there exists a linear relationship between the activation energy and the natural logarithm of the pre-exponential factor at different heating rates.
出处
《华南理工大学学报（自然科学版）》
EI
CAS
CSCD
北大核心
2014年第10期75-81,共7页
Journal of South China University of Technology(Natural Science Edition)
基金
广东省自然科学基金资助项目(S2013010016748)
关键词
氢氧化钙
热分析
多重速率扫描法
反应动力学
机理函数
calcium hydroxide
thermal analysis
multiple scanning method
reaction kinetics
mechanism function
