【摘要】 利用X 650型扫描电镜比较徐州沛城天然焦和徐州韩桥烟煤表观形貌,并在Thermax500型加压热重分析仪上采用非定温热分析法研究天然焦的热解特性.利用Coats-Redfern积分法对天然焦的热解过程进行了动力学分析,得出了天然焦在不同升温速率、不同粒径尺寸、不同操作压力下的动力学参数,相关系数绝大部分在0.99以上.试验结果表明:天然焦比煤具有更发达的孔隙结构;随着升温速率的增加,试样热解的TG曲线向高温区偏移,DTG曲线峰值位置也相应地移向高温区,总失重率、热解活化能增幅较小;小粒径试样的热解活化能较低,有利于挥发分的析出;增加操作压力,热解活化能随之增大,但增加幅度逐渐缓慢,热解失重率降低.更多还原

【Abstract】 The morphology comparison between natural coke(Peicheng mine,Xuzhou,China) and bituminous coal(Hanqiao mine,Xuzhou,China) was made by scanning electron microscopy(SEM).The pyrolysis characteristics of natural coke were investigated under non-constant temperature conditions with Thermax500 pressurized thermogravimetric(TG) apparatus.The kinetics of pyrolysis processes was studied by Coats-Redfern integration method,and the kinetic parameters of natural coke were gained under different conditions,such as heating rate,coke size and operation pressure.The correlation coefficients are above 0.99 in most of the tests.Test results show that the pore structure of the natural coke is more developed than that of coal.As the heating rate increases,the TG curve shifts to the high temperature area and the peak of DTG curve goes to the high temperature area accordingly,but the total weight loss and activation energy of pyrolysis fluctuate little.As the grain size reduces,the activation energy decreases and the volatile release becomes quicker.As the pressure increases,the activation energy of pyrolysis increases,but the increasing amplitude and the total weight loss slow down.更多还原