印尼褐煤和山西烟煤燃烧的热重实验及反应动力学分析

Thermogravimetric experiments and reaction kinetics analysis on combustion of indonesia lignite and shanxi bituminous coal

为了掌握印尼褐煤的燃烧性能,为电厂掺烧褐煤提供理论依据,采用热重分析仪进行了印尼褐煤和山西烟煤的着火燃烧实验。利用TG-DTG曲线法确定了两种煤的着火温度、燃尽温度和最大失重速率点温度,并通过Coats-Redfern积分法进行了煤粉燃烧的反应动力学分析,研究了煤种、升温速率和煤粉粒径对煤粉燃烧特性及动力学特性的影响。结果表明:相较于山西烟煤,印尼褐煤的着火温度、燃尽温度最大失重速率点温度以及燃烧反应活化能均较低,表明印尼褐煤的燃烧性能优于山西烟煤;在热滞后效应的影响下,随着升温速率的增大,印尼褐煤和山西烟煤的着火温度、燃尽温度和最大失重速率点温度均提高,活化能降低,燃烧更加剧烈;煤粉粒径的增大使煤粉的着火温度、燃尽温度、最大失重速率点温度以及活化能均提高,不利于煤粉的着火和燃尽;煤粉粒径对印尼褐煤特性的影响远比山西烟煤明显,可通过调控煤粉细度调节褐煤燃烧特性。

In order to grasp the combustion performance of Indonesia lignite and provide theoretical basis for power plants to co-fire lignite,the ignition and combustion characteristics of Indonesia lignite and Shanxi bituminous coal were analyzed by thermogravimetric analysis method.The ignition temperature,burnout temperature and the maximum weight loss rate temperature were determined by TG-DTG method.Moreover,the reaction kinetics of the pulverized coal was analyzed by the Coats-Redfern integration method,and the influence of coal type,heating rate and particle size on pulverized coal combustion characteristics and reaction kinetics were analyzed.The results show that,the ignition temperature,burnout temperature,maximum weight loss rate temperature and activation energy of Indonesia lignite were lower than that of the Shanxi bituminous coal,suggesting the combustion performance of Indonesia lignite is better.On account of thermal hysteresis effect,with the increasing heating rate,the ignition temperature,burnout temperature and maximum weight loss rate temperature of the above two coals increased,while the activation energy decreased,implying the coal would burn more strongly.As the particle size increased,the ignition temperature,burnout temperature and maximum weight loss rate temperature increased,which was not conducive to the coal’s ignition and burnout.At last,the results also show the particle size had more obvious influence on Indonesia lignite than on Shanxi bituminous coal,suggesting the lignite combustion condition can be adjusted by controlling the coal fineness.