镁钙砂表面碳酸化反应动力学计算中的数据处理

Data Processing in Kinetics Calculation of MgO-CaO Powder Surface Carbonation

用数值分析法对镁钙砂碳酸化反应热重试验数据进行平滑处理,减小了因镁钙砂的显微结构特性导致的热重试验微商数据离散程度对动力学计算的影响,提高了线性拟合相关系数.用模式配合法确定了镁钙砂碳酸化反应动力学“三因子”,结果表明:反应前期(α<33%)表观活化能Ea为31.9kJ/mol,指前因子A为0.23s-1,最可几机理可用随机成核、随后生长模式函数Avrami-Erofeev方程描述,其微分表达式为n=2的Avrami-Erofeev方程,f(α)=(1-α)[-ln(1-α)]-1/2;反应后期(α>33%)表观活化能Ea为101.8kJ/mol,指前因子A为6.4×102,最可几机理可用三维扩散模式函数D3描述,其微分表达式为Jander方程,f(α)=3(1-α)2/3/(2(1-(1-α)1/3)).

Smoothing the TG data of MgO-CaO powder surface carbonation with numerical method, the influence is reduced of the dispersion in TG data on kinetics calculating caused by the microstructure of MgO-CaO powder, and correlation coefficient of linear fitting is improved through data processing. The kinetic triplets are decided by modal fitting method. The results are as follows： During the first stage of the reaction （a〈33%）,the apparent activation energy Ea is 31. 9 kJ/mol and the preexponential factor A is 0. 23 s^-1. The most probable mechanism could be described by Avrami-Erofeev model function of nucleus forming and growing; its differential function is Avrami-Erofeev equation （n=2）： f（a） = （1-a）[-ln（1-a）]^-1/2. The anaphase of the reaction（a〈33%）,the apparent activation energy Ea is 101.8 kJ/mol and the preexponential factor A is 6.4×10^2s^-1, the most probable mechanism could be described by of three-dimension diffusion, its differential function is Jander equation： f（a） = （1-a）^2/3/（2（1-（1-a）^1/3））.