A thermogravimetric analyzer was employed to investigate the thermal behavior and extract the kinetic parameters of Canadian lignite coal. The pyrolysis experiments were conducted in temperatures ranging from 298 K to 1173 K under inert atmosphere utilizing six different heating rates of 1, 6, 9, 12, 15, and 18 K min⁻¹, respectively. There are different techniques for analyzing the kinetics of solid-state reactions that can generally be classified into two categories: model-fitting and model-free methods. Historically, model-fitting methods are broadly used in solid-state kinetics and show an excellent fit to the experimental data but produce uncertain kinetic parameters especially for nonisothermal conditions. In this work, different model-free techniques such as the Kissinger method and the isoconversional methods of Ozawa, Kissinger-Akahira-Sunose, and Friedman are employed and compared in order to analyze nonisothermal kinetic data and investigate thermal behavior of a lignite coal. Experimental results showed that the activation energy values obtained by the isoconversional methods were in good agreement, but Friedman method was considered to be the best among the model-free methods to evaluate kinetic parameters for solid-state reactions. These results can provide useful information to predict kinetic model of coal pyrolysis and optimization of the process conditions.

中文翻译：

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褐煤的动力学研究及热分解行为

用热重分析仪研究加拿大褐煤的热行为并提取其动力学参数。热解实验是在惰性气氛下，在298 K至1173 K的温度范围内进行的，采用了6、9、12、15和18 K min ^-1的六种不同加热速率， 分别。有多种分析固态反应动力学的技术，通常可分为两类：模型拟合法和无模型法。从历史上看，模型拟合方法广泛用于固态动力学，并且显示出与实验数据的极佳拟合，但是会产生不确定的动力学参数，尤其是在非等温条件下。在这项工作中，采用和比较了Ozawa，Kissinger-Akahira-Sunose和Friedman的Kissinger方法和等转化方法等不同的无模型技术，以分析非等温动力学数据并研究褐煤的热行为。实验结果表明，通过等转化法获得的活化能值吻合良好，但是弗里德曼方法被认为是评估固态反应动力学参数的无模型方法中最好的方法。这些结果可提供有用的信息，以预测煤热解的动力学模型和工艺条件的优化。