煤程序升温与等温热解特性及动力学比较研究

采用热重分析仪和微型流化床分别考察了不同煤阶五个煤样的程序升温和等温快速热解的挥发分析出特性和反应动力学.程序升温实验揭示了热解气体的析出顺序依次为CO2,CO,CH4和H2,而等温热解实验证明CO2和CO的析出先于CH4和H2.微型流化床等温快速热解的挥发分气体总量析出活化能为17kJ/mol～35kJ/mol,小于程序升温热解的活化能.CO2和CO的反应级数与1接近,而CH4和H2的反应级数与1偏差较大,反映了这两类气体在生成机制上存在差异.

CAMPARATIVE STUDY ON COAL PYROLYSIS VIA PROGRAMMED AND ISOTHERMAL HEATING

This article investigated the volatile evolution characteristics and estimated the corresponding reaction kinetics of five coal samples belonging to different coal rank in the pyrolysis via programmed and isothermal heating realized in thermogravimetric analyzer and micro fluidized bed(MFB) respectively.The pyrolysis via programmed heating demonstrated that the release sequence of the volatile gases was CO2,CO,CH4 and H2 in succession,whereas the isothermal pyrolysis in MFB showed that the gas release of CO and CO2 was also preceded CH4 and H2.For the isothermal fast pyrolysis in MFB,the activation energy of the five coal samples was 17 kJ/mol-35 kJ/mol,obviously lower than that for the pyrolysis via programmed heating.The reaction order of CO2 and CO was found to be close to 1 and that for the formation of CH4 and H2 obviously deviated from 1,which demonstrates essentially the difference in the formation mechanism for these two groups of volatile gases.