The combustion of Jiaozuo anthracite and Yunfu bituminous coal chars under O2/CO2 atmosphere was studied by isothermal thermogravimetric analysis. The characteristics of coal char combustion at different temperatures were examined in O2/CO2 environment. The relationship between reaction rate and carbon conversion of two coal chars was analyzed by the random pore model (RPM), and compared with the simulations from the unreacted shrinking core reaction model (Model I ) and the integrated model (Model Ⅱ ). The results show that the random pore model is the best to fit the experimental data under different reaction conditions, and the correlation coefficient is 0. 986. Comparison for the results from RPM, Model I and Model Ⅱ shows that activation energy of isothermal combustion of Jiaozuo anthracite under O2/CO2 atmosphere is much higher than that of Yunfu bituminous, and the rate constant is larger when the combustion temperature of coal chars is higher. The random pore model is more accurate to describe the characteristics of coal char combustion under O2/CO2 atmosphere because the influence of variation of pore structure on coal char combustion can be well reflected by parameter ψ used in RPM.%在热重分析仪上对焦作无烟煤焦和云浮烟煤焦O2/CO2条件下燃烧特性进行研究.确定在不同温度下不同煤焦O2/CO2燃烧的特征.利用随机孔模型(RPM)表征两种煤焦反应速率与碳转化率的关系,同时与未反应缩核模型(Model Ⅰ)和混合模型(Model Ⅱ)的拟合结果进行比较.研究表明,在不同反应条件下,随机孔模型具有最佳的拟合效果,相关系数都在0.986以上.比较RPM、ModelⅠ和Model Ⅱ计算结果发现,焦作无烟煤焦的O2/CO2等温燃烧的活化能比云浮烟煤焦的高,且同一煤种燃烧反应温度越高反应速率常数越大.由于随机孔模型的结构参数ψ可以很好地表现孔结构变化对煤焦燃烧反应的影响,因此随机孔模型能更加准确地描述煤焦O2/CO2燃烧特征.
展开▼
