微型流化床-快速过程红外热分析仪对CaCO_3热分解的动力学研究

Kinetic Study on CaCO_3 Decomposition via MFB-IR Thermal Analyzer

本文使用程序升温热重分析仪和自主开发的微型流化床(MFB)一快速过程红外(IR)热分析仪进行CaCO_3热分解动力学的实验研究。通过MFB-IR系统实验获得的碳酸钙分解活化能为107.7 kJ/mol,处于文献报道的范围之内;反应动力学模型符合形核与成长(n=2/3)模型。当转化率小于30%时,通过MFB-IR系统获得的CaCO_3分解活化能与热重较一致,但在转化率大于30%情况下,MFB-IR中获得的分解活化能随转化率的变化比热重分析所得活化能变化明显。同时,其活化能数值小于通过热重分析仪实验获得的数值。

In this paper,a temperature programmed TG analyzer and the new built MFB-IR thermal analyzer are compared to study the decomposition of calcium carbonate by investigating the reaction rate and kinetic parameters.The apparent activation energy of calcium carbonate decomposition,when the conversion is zero(Eα = 0),getting from MFB-IR thermal analyzer is 107.7 kJ/mol,which is within the range of other literature's reports.The MFB-IR thermal analyzer's kinetic curves can be interpretated with the Avrami-Erofeev model(nucleation and growth,n = 2/3).At the early stage of decomposition,the two analyzers get similar apparent activation energy.But with the conversion increase,the apparent activation energy decreases more in MFB than in TG analyzer.