混煤燃烧反应动力学参数的热重研究

Thermo-gravimetric Research on Dynamic Combustion Reaction Parameters of Blended Coals

采用热天平,对两种标准煤的混煤燃烧反应动力学参数进行了实验研究。首先对热天平实验的重复性进行了验证,确保获得的实验参数准确、可靠。采取不同的燃烧方式分析动力学参数的变化。非等温燃烧的研究表明,以特征温度区间计算,表观活化能和频率因子均随混煤中烟煤比例的增加而降低。升温速率增加,混煤燃烧的表观活化能有所下降。等温燃烧的研究表明,模型的选择对动力学参数的研究影响很大,通过计算,认为球对称收缩核模型适合于混煤等温燃烧动力学参数的研究。表观活化能的计算结果表明高活性煤种的存在可以很好的改善混煤的着火性能,并且存在最佳掺混比例。

Experimental research on dynamic parameters of combustion reaction of a blend of two standard coals was carried out by thermo-gravimetric balancing. In the first place, replication quality was verified to ensure accuracy and reliability of the experimental data. Different ways of combustion methods were adopted for analyzing variations of the dynamic parameters. Non-isothermal combustion shows that the apparent activation energy and the frequency factor both decreased with increasing bituminous coal content in the blend. The apparent activation energy of the blend during combustion decreases with increasing heating-up rate. Research on isothermal combustion shows that reaction model selection has a great influence on the dynamic parameters. And according to calculation, a sphere symmetric shrinking nucleus model is considered to serve the purpose of studying dynamic parameters of isothermal combustion of blended coal very well. Apparent activation energy calculating results show that the high reactive coal can improve the ignition property of blended coals and moreover there exists an optimum blending ratio.