煤泥热解和燃烧过程的行为特性研究

Study on the BehaviorCharacteristics of Coal Slime Pyrolysis and Combustion Process

为了研究煤泥的热化学转化特性,本文利用热重分析仪进行了不同升温速率(10℃/min、20℃/min、30℃/min)下的热解和燃烧试验,采用Flynn Wall Ozawa(FWO)和Kissinger Akahira Sunose(KAS)2种动力学计算方法对煤泥热解和燃烧过程的动力学参数进行计算并比较。结果表明:随升温速率的提高,煤泥的热解和燃烧过程的热重(TG)与微商热重(DTG)曲线向高温方向偏移。煤泥热解过程的DTG曲线主要呈现两个明显的失重峰。而燃烧过程中,由于挥发物和固定碳燃烧过程的重叠,在300~580℃范围内其DTG曲线出现一个明显的失重峰,燃尽时间随升温速率的增大而减小。FWO法和KAS法计算得到的煤泥热解第一阶段活化能分别为175.78 kJ/mol和163.40 kJ/mol,第二阶段活化能分别为225.37 kJ/mol和209.51 kJ/mol。FWO法和KAS法计算得到的煤泥燃烧过程活化能分别为109.12 kJ/mol和102.65 kJ/mol,2种计算方法的结果具有较好的一致性,2种动力学计算方法综合使用有利于对煤泥的热解和燃烧过程形成更为全面的认识。

In order to study the thermochemical conversion characteristics of coal slime,pyrolysis and combustion experiments at different heating rates(10℃/min,20℃/min,30℃/min)were carried out using a thermogravimetric analyzer.Two kinetic methods of calculation,Flynn Wall Ozawa(FWO)and Kissinger Akahira Sunose(KAS),were used to calculate and compare the kinetic parameters of coal slime pyrolysis and combustion process.The results indicate that with the increase of heating rate,the thermal gravimetric(TG)and differential thermal gravimetric(DTG)curves of pyrolysis and combustion of coal slime shift towards high temperature direction.The DTG curve of the coal slime pyrolysis mainly presents two obvious weight loss peaks.During the combustion process,due to the overlap of volatile and fixed carbon combustion processes,a significant weight loss peak appears in the DTG curve within the range of 300—580℃,and the burnout time decreases with the increase of heating rate.The activation energies of the first stage of coal slurry pyrolysis calculated by the FWO method and KAS method were 175.78 kJ/mol and 163.40 kJ/mol,respectively,and the activation energies of the second stage of pyrolysis were 225.37 kJ/mol and 209.51 kJ/mol,respectively.The activation energies of coal slurry combustion process calculated by the FWO method and KAS method are 109.12 kJ/mol and 102.65 kJ/mol,respectively.The results obtained by these two methods have good consistency,and the comprehensive use of the two kinetic calculation methods is conducive to forming a more comprehensive understanding of the pyrolysis and combustion process of coal slurry.