摘要
为了研究升温速率对生物质三组分的热解特性影响,利用同步热分析-质谱联用仪(Thermogravimetry/Differential Scanning Calorimetry-Mass Spectrum,TG/DSC-MS)对不同升温速率(μ=1℃/min、5℃/min、10℃/min、20℃/min)下的热解试验进行分析,并采用Coats-Redfern法、Doyle法和分布活化能模型(Distribution of Activation Energy Model,DAEM)法对热解动力学参数进行计算与比较。结果显示:1)随升温速率增大,三组分生物炭产率减小,热解气和热解油产率增大。2)随升温速率增大,气体产物最大析出速率增大。其中,当升温速率为1℃/min时,气体产物析出速率变化不大。3)随升温速率增大,三组分热解失重率变化不大。4)随升温速率增大,DTG(Derivative Thermogravimetry)曲线最大失重峰右移,最大热解失重速率减小。5)随升温速率增大,纤维素DSC曲线最大吸热峰右移,峰值增大,吸热峰面积增大。此外,半纤维素和木质素最大放热峰右移,峰值增大,放热峰面积增大。利用不同的动力学方法计算得到的动力学参数结果不同。其中,Coats-Redfern法计算得到的纤维素活化能最大,为194.84 kJ/mol;Doyle法和DAEM法得到的活化能分别为177.32 kJ/mol和160.71 kJ/mol。半纤维素和木质素动力学参数计算结果与纤维素相反,Coats-Redfern法计算的活化能最大值分别为42.61 kJ/mol和22.11 kJ/mol;Doyle法计算得到的活化能分别为164.05 kJ/mol和129.05 kJ/mol;DAEM法计算得到的活化能分别为147.30 kJ/mol和117.36 kJ/mol。通过Doyle法和DAEM法可得到三组分在热解过程中活化能与转化率的变化关系,且2者变化趋势基本相同。
To study the effects of heating rates on the pyrolysis characteristics of three biomass components,pyrolysis experiments at different heating rates(μ=1℃/min,5℃/min,10℃/min,and 20℃/min)were carried out by synchronous thermal analysis-mass spectrometry(TG/DSC MS).A Coats-Redfern method,Doyle method,and DAEM method were used to calculate and compare the pyrolysis kinetics parameters.The results show that with the increase of heating rate,the pyrolysis weight loss of the three components has little change;the yield of three-component biochar decreases,while the yield of pyrolysis gas and pyrolysis oil increases;and the maximum rate of gas product precipitation increases.When the heating rate is 1℃/min,the rate of gas product precipitation has little change.The maximum weight loss peak of DTG curve shifted to the right,and the maximum pyrolysis weight loss rate decreased.The maximum endothermic peak of DSC curve of cellulose shifted to the right,the peak value increased,and the endothermic peak area increased.The maximum exothermic peak of hemicellulose and lignin shifted to the right,the peak value increased,and the exothermic peak area increased.The results of kinetic parameters obtained by different kinetic calculation methods are different.The activation energy of cellulose calculated by the Coats-Redfern method is relatively large,which is 194.84 kJ/mol.The average values obtained by the Doyle method and DAEM method are 177.32 kJ/mol and 160.71 kJ/mol,respectively.While the result of hemicellulose and lignin are the opposite,the maximum results of the Coats-Redfern method were 42.61 kJ/mol and 22.11 kJ/mol,respectively.The results obtained by the Doyle method were 164.05 kJ/mol and 129.05 kJ/mol.The results calculated by the DAEM method were 147.30 kJ/mol and 117.36 kJ/mol.And the variation curves of activation energy with weight loss rate during the pyrolysis of the three components can be obtained by both the Doyle method and the DAEM method,and the overall variation trends are almost the same.
作者
梅艳阳
刘孔荣
李文琪
柴鸿川
MEI Yanyang;LIU Kongrong;LI Wenqi;CHAI Hongchuan(School of Mechanical and Power Engineering,Henan Polytechnic University,Jiaozuo 454000,Henan,China)
出处
《安全与环境学报》
CAS
CSCD
北大核心
2023年第10期3723-3732,共10页
Journal of Safety and Environment
基金
河南省科技攻关项目(222102320277)。
关键词
环境科学技术基础学科
生物质
热解
升温速率
动力学
basic subject of environmental science and technology
biomass
pyrolysis
heating rate
kinetics
