5种乔木可燃物不同升温速率下的热重研究  

Thermogravimetric study of 5 treespecies at different heating rates

作　　者：张今奇 李向晨 李显玉 周梅[3] Zhang Jinqi;Li Xiangchen;Li Xianyu;Zhou Mei(Chifeng Forestry Research Institute,Inner Mongolia Chifeng 024005,China;National Observation and Research Station of Ancient Chifeng Forest Ecosystem in Inner Mongo-liam,Inner Mongolia Chifeng 024000,China;Inner Mongo-lia Agricultural University,Inner Mongolia Hohhot 010019,China)

机构地区：[1]赤峰市林业科学研究所,内蒙古赤峰024005 [2]内蒙古赤峰森林生态系统国家定位观测研究站,内蒙古赤峰024000 [3]内蒙古农业大学,内蒙古呼和浩特010019

出　　处：《消防科学与技术》2022年第12期1732-1736,共5页Fire Science and Technology

基　　金：国家自然科学基金项目(41563006)

摘　　要：为探究不同升温速率下5种典型乔木可燃物的热解特性,加快和完善内蒙古大兴安岭地区森林燃烧性研究,以白桦、黑桦、兴安落叶松、蒙古栎、山杨的小枝为主要研究对象,基于OFW热重分析法,在空气气氛中,以氧气为载气,加热区间为30~600℃,首先升温至100℃并保持5 min,气体流量为20mL/min,然后分别以40,60,80℃/min升温速度率升温。通过TG-DTG曲线分析试样的热解过程,利用OFW法对试样的快速热解阶段进行动力学分析并绘制参数趋势图。结果表明,升温速率对热解过程的影响主要集中在失重阶段,随着升温速率的增加,热解特征温度增加,试样失重率增大。在此阶段,升温速率为60℃/min时,5种典型乔木可燃物热解程度排序为:兴安落叶松>蒙古栎>山杨>白桦>黑桦;OFW法分析下的5种典型乔木可燃物活化能随转化率变化,活化能计算结果可靠,模型较优。山杨活化能区间为659.788~712.664 kJ/mol,调整后的R^(2)为0.962 6~0.999 7,活化能随转化率的增加呈现先减少后增加的趋势,反应进程中后段依然保持良好的放热反应。To explore the pyrolysis characteristics of five typical tree species at different heating rates, the twigs of Betula platyphylla, Betula davurica, Larix gmelinii, Quercus mongolica and Populus simonii were taken as the main research objects.Based on OFW thermogravimetric analysis, the heating range was from 30 ℃ to 600 ℃ with oxygen as carrier gas in air atmosphere. Firstly, the temperature was raised to 100 ℃ and kept for 5 min. The gas flow rate was 20 mL/min, then the temperature was raised at 40, 60, 80 ℃/min respectively. TG-DTG curve was used to analyze the pyrolysis process of the sample,and OFW method was used to analyze the kinetics of the rapid pyrolysis stage of the sample. The results show that the effect of heating rate on the pyrolysis process is mainly concentrated in the weight loss stage. As the heating rate increases, the pyrolysis characteristic temperature increases and the weight loss rate of the sample increases. At this stage, when the heating rate was60 ℃/min, the pyrolysis degree of five typical tree species was Larix gmelinii>Quercus mongolica>Populus davidiana>Betula platyphylla>Betula platyphylla. The activation energy of the five tree species analyzed by OFW method changed with the conversion rate. The activation energy calculation results were reliable and the model was better. The activation energy range of Populus davidiana was 659.788~712.664 kJ/mol, and the adjusted R^(2) range was 0.962 6~0.999 7. The activation energy decreased first and then increased with the increase of conversion rate, and good exothermic reaction was still maintained in the latter part of the reaction process.

关 键 词：热解动力学 OFW法 升温速率 转化率 表观活化能 热重 

分 类 号：S762.3[农业科学—森林保护学] TK121[农业科学—林学]