高二氧化碳浓度下石灰石的热分解反应动力学  

Kinetics of Thermal Decomposition Reaction of Limestone at High Carbon Dioxide Concentration

作　　者：李辉[1,2] 张乐乐[1] 段永华[1] 闵永刚[1,2] 

机构地区：[1]西安建筑科技大学材料与矿资学院 [2]陕西循环经济工程技术院,西安710055

出　　处：《硅酸盐学报》2013年第5期637-643,共7页Journal of The Chinese Ceramic Society

基　　金：国家自然科学基金项目(51274159);陕西省重大科技创新项目(2012zk06-2)

摘　　要：用热重分析仪,在升温速率5～20K/min范围内,研究CO2浓度对石灰石热分解反应动力学参数的影响及高CO2浓度气氛下两种化学成分与矿物组成不同的石灰石的热分解反应动力学。采用改进的双外推法计算这两种石灰石的热分解反应动力学参数。结果表明:石灰石热分解反应的活化能与气氛中的CO2浓度呈指数增加关系;在高CO2浓度气氛条件下石灰石的热分解过程机理模型为随机成核和随后生长模型,得到了反应机理函数,CO2浓度不同,反应级数不同,反应级数的变化范围为2/5～2/3;CO2浓度越高,石灰石热分解的活化能越高,反应级数越大;在相同CO2浓度气氛条件下,石灰石中含有一定量白云石有助于其分解反应的进行。The effect of CO2 concentration on the thermal decomposing reaction kinetic parameters of limestone and the kinetics difference of thermal decomposition reaction of two limestones with different chemical and mineral compositions at a high CO2 concentration was investigated via thermogravimetric analysis. The range of heating rate was from 5 to 20 K/min. The kinetic parameters of the thermal decomposition of two limestones were calculated via an improved double extrapolation method. The results show that the activation energy of thermal decomposition of limestone increases exponentially with the increase of CO2 concentration. The model of thermal decomposition process of limestone at a high CO2 concentration was regarded as a randomly nucleation and growth model, obtaining the mechanism function. The reaction order varied from 2/5 to 2/3 at different CO2 concentrations. Moreover, the higher the CO2 concentration, the higher activation energy of thermal decomposition of limestone and greater reaction order could be. A certain amount of dolomite in limestone could favor the decomposition reaction of limestone.

关 键 词：高二氧化碳浓度 石灰石分解 动力学 改进的双外推法 热重分析 

分 类 号：TQ201[化学工程—有机化工] O643[理学—物理化学]