神木长焰煤CO_(2)气化动力学不同模型的拟合分析

Fitting analysis of different models of CO gasification kinetics of Shenmu long flame coal

为获得适用、精度高的气化动力学模型,介绍并研究了5种不同的气化动力学模型对神木长焰煤的适用性。利用德国NETZSCH STA 409PG热天平,采用等温法进行神木长焰煤CO_(2)气氛中气化动力学分析。将碳转化率-时间的关系曲线分别用随机孔模型(RPM)、未反应芯缩核模型(SCM)、混合模型(BM)、均相模型(HM)、修正体积模型(MVM)进行拟合并做出分析与比较,采用相关系数R^(2)检验拟合结果与试验结果的符合程度,发现5种模型的拟合精度从高到低依次为:混合模型>修正体积模型>均相模型>未反应芯缩核模型>随机孔模型,混合模型更适用于神木长焰煤的CO_(2)气化反应动力学模拟。根据阿伦尼乌兹(Arrhenius)公式,得到不同模型的活化能和指前因子并进行对比,R2检验结果从高到低依次为:随机孔模型>未反应芯缩核模型>混合模型>均相模型>修正体积模型。结果表明:900和1000℃拟合效果普遍优于800℃,在气化模型拟合中,混合模型最为合适;在活化能分析时,随机孔模型拟合最佳;不同模型预测的CO_(2)气化活化能在61~143 kJ/mol,与相关文献的结果基本一致。

In order to obtain a suitable and accurate gasification kinetic model,the applicability of five different gasification kinetic models for Shenmu long flame coal was introduced and studied.The gasification kinetics of Shenmu long flame coal in CO_(2) atmosphere was analyzed by using NETZSCH STA 409 PG thermobalance and isothermal method.The relationship between carbon conversion rate and time was determined by random pore model(RPM),unreacted shrinkage core model(SCM),brewing model(BM),Homogeneous model(HM)and modified volume model(MVM)fitted,analyzed and compared.Correlation coefficient R^(2)was used to test the consistency between fitting results and experimental results,and it was found that the accuracy of the five models was in order from high to low:brewing model>modified volume model>homogeneous model>unreacted shrinkage core model>random pore model,and brewing model was more suitable for the kinetics simulation of CO_(2) gasification reaction of Shenmu long flame coal.According to the Arrhenius formula,the activation energy and the pre-exponential factors of different models were obtained and compared.The R^(2)test result was in order from high to low:random pore model>unreacted shrinkage core model>brewing model>homogeneous model>modified volume model.The experimental results showed that the fitting effect of 900℃and 1000℃is generally better than that of 800℃.In the fitting of gasification model,the mixed model is the most suitable.In the analysis of activation energy,the random pore model is the best fit.The range of CO_(2) gasification activation energy predicted by different models is between 61-143 k J/mol,which is basically consistent with the results reported in relevant literatures.