热处理对煤焦气化和燃烧反应性的影响

THE INFLUENCES OF HEAT TREATMENT ON THE REACTIVITIES OF CHAR GASIFICATION AND COMBUSTION

利用非等温热重法研究了不同温度下制得的褐煤煤焦CO_2气化和燃烧反应动力学,得到了各反应的反应性指数、活化能、反应速率常数等动力学参数。结果表明,煤焦两种反应的反应性指数、活化能均随着热处理温度的升高而增大,即煤焦的反应性随着热处理温度的升高而减小。矿物质对煤焦的两种反应均具有催化作用,该作用随着热处理温度的升高而减小。煤焦两种反应的反应速率常数k随热处理温度升高显示出不同的变化趋势,反映了煤焦物理化学特性对气化和燃烧反应影响的差异和两种反应动力学过程的不同。

The reaction kinetics of lignite chars CO2 gasification and combustion were studied by non-isothermal thermogravimetric analysis.The kinetic parameters of the two reactions,including reactivity index,activation energy,reaction rate constant,were derived.It was found that the reactivity indexes and activation energy of both chars CO2 gasification and combustion increased with increasing heat treatment temperature,indicating that the reactivities of chars decreased with the temperature.Mineral matter was found to have catalytic effects on both reactions,but the effects gradually decreased with increasing the treatment temperature.The variations of the reaction rate constants of the char CO2 gasification combustion with the treatment temperature showed opposite trends,implying the differences in the effects of char physicochemical properties and the kinetic processes between of the two reactions.