水曲柳林下凋落物热解特性及动力学分析

Pyrolysis characteristics and kinetic analysis of litter in fraxinusmandshurica plantation

利用热重分析法对水曲柳林下凋落物的热解行为进行研究,分析不同的试验气氛、升温速率及粒径对热解过程的影响,采用Coast-Redfern法进行动力学分析。结果表明:林下凋落物热解分为失水、轻微失重、主要失重和炭化4个阶段,试样的稳定性大小依次为:水曲柳树枝>水曲柳树皮>水曲柳树叶>福王草;试样在氮气气氛下有1个失重峰,在空气气氛下有2个失重峰,在空气气氛下失重率较大,热解更充分;随着升温速率增加,热失重曲线向高温侧移动,失重速率增加,且存在滞后效应;粒径大小对试验影响较小,60目粒径试样失重率最大;4种试样活化能由大到小分别为水曲柳树枝、水曲柳树皮、水曲柳树叶和福王草。

The thermogravimetric analysis was used to study the pyrolysis behavior of the litter under the fraxinusmandshurica forest.The effects of different experimental atmospheres,heating rates and particle sizes on the pyrolysis process were analyzed.The Coast-Redfern method was used for kinetic analysis.The results showed that the pyrolysis of the litter under the forest was divided into four stages:water loss,slight weight loss,main weight loss and carbonization.The stability of the samples was:branches>bark>leaves>Prenanthestatarinowii grass.There is one weight loss peak in nitrogen atmosphere,two in air atmosphere,and the weight loss rate is larger in the air atmosphere,and the pyrolysis is more sufficient.As the heating rate increases,the thermal weight loss curve moves to the high temperature side,the weight loss rate increases,and there is a hysteresis effect.The particle size has little effect on this experiment,the weight loss rate of the 60 mesh particle size sample is the largest.The activation energy of the four samples is from branches to bark,leaves and Prenanthestatarinowii grass.