CaCO_3分解机理的研究  

Research on the Decomposition Mechanism of CaCO_3

作　　者：郑瑛[1] 陈小华[1] 郑楚光[1] 

机构地区：[1]华中科技大学煤燃烧国家重点实验室,武汉430074

出　　处：《动力工程》2004年第2期280-284,共5页Power Engineering

基　　金：国家重点基础研究专项经费资助(G1999022205);国家自然科学基金资助项目(50006002;50376016)

摘　　要：在升温速率为5～30K/min的范围内利用热天平对平均粒径为13.4μm的CaCO3进行了分解过程的实验研究。应用等转化率法,在不假定机理(函数的情况下,得到了CaCO3分解的活化能随转化率的变化规律,并将转化率外推为零,得到了理论上新物相晶核形成时的活化能Eα→0=243.62kJ/mol。同时,对于N2气氛,不同升温速率下CaCO3的热分解,在假定CaCO3分解机理函数的情况下,得到了30种不同机理函数所对应的动力学参数。将升温速率外推为零,得到了理论上系统处于热平衡状态下的动力学参数Eβ→0与lnAβ→0。将Eβ→0与Eα→0相比较,确定了CaCO3分解的最可能机理是n=2/3的成核与生长过程。Decomposition mechanism of calcium carbonate is studied by means of a thermogravimetric technique. The heating rate is 5～30K/min, and the mean particle size of the sample that is measured by Malvern Laser Master size Analyser is (13.4μm). The method of equal conversion rate, which the decomposition mechanism needn't be proposed, is used to determinate the decomposition active energy value of CaCO_3. The derived value E _( α →0), which the conversion fraction is extrapolated to zero, is (243.62kJ/mol). Meanwhile, the active energy values of CaCO_3 with different heating rate in nitrogen, which the mechanism is defined, are obtained. Then, the active energy value E _( β →0), which the heating rate is extrapolated to zero, is obtained. Comparing E _( β →0) with E _( α →0), the Decomposition mechanism of CaCO_3 is concluded to be nuclear producing and growing process ( n =2/3). Tables 4 and refs 6.

关 键 词：工程热物理 CACO3 反应动力学 分解机理 双外推法 热重分析 

分 类 号：TK16[动力工程及工程热物理—热能工程]