黑龙江省6种乔木叶片热解特性及气体释放特征

森林可燃物是森林火灾发生的基础,地表死可燃物是森林可燃物的重要组成部分,研究地表死可燃物的热解特性和气体释放对探究森林火灾对大气环境和碳平衡的影响及森林火灾的预防和扑救具有重要意义.本研究对黑龙江省6种乔木(樟子松、红皮云杉、水曲柳、胡桃楸、蒙古栎和白桦)地表凋落的叶片进行热重分析和气体释放分析,探究森林可燃物的热解过...

Pyrolysis and gas emissions characteristics of six tree species in Heilongjiang Province,China

Forest fuels are the basis of fire occurrences,while ground dead fuels are an important part of forest fuels.Undestanding the pyrolysis characteristics and gas emissions of forest fuels is of great significance to explore the effects of forest fire on atmospheric environment and carbon balance,as well as to prevent and combat forest fire.In this study,the thermogravimetric analysis and gas emission analysis were conducted on leaf litter of six tree species(Pinus sylvestris var.mongolica,Picea koraiensis,Fraxinus mandshurica,Juglans mandshurica,Quercus mongolica,Betula platyphylla) in Heilongjiang Province to explore the pyrolysis process and combustibility of forest fuels,to analyze their pyrolysis characteristics,pyrolysis kinetics characteristics,gas emission characteristics.A four-dimensional evaluation of their combustibility was conducted based on pyrolysis parameters.The results showed that the pyrolysis temperature of holocellulose in the leaves of those six tree species ranged in 143.31-180.48 ℃ at the beginning and 345.04-394.38 ℃ at the end,lignin pyrolysis temperature ranged in 345.04-394.38 ℃ at the beginning and 582.85-609.31 ℃ at the end.The pyrolysis of the six kinds of arbor blades during the pyrolysis process affected fuel ash content,quality and temperature of the total pyrolysis.The activation energies of two main pyrolysis stages of leaves of six tree species were 18.88-27.08 kJ·mol^-1 and 13.25-27.54 kJ·mol^-1,respectively,and the pre-exponential factors were 3.13-26.28 min^-1 and 1.30-22.55 min^-1.The holocellulose activation energy and pre-exponential factor of the pyrolysis stage for P.koraiensis,F.mandshurica,Q.mongolica,and B.platyphylla were greater than that of the lignin pyrolysis stage,while the opposite was true for P.sylvestris var.mongolica and J.mandshurica.The release amounts of CO and CO₂ at the pyrolysis stage of the holocellulose was 535.16-880.11 mg·m^-3 and 7004.97-10302.05 mg·m^-3,and that at the pyrolysis stage of lignin was 240.31-1104.67 mg·m^-3 and 20425.60-33946.68 mg·m^-3,respectively.The release of CO and CO₂ at the pyrolysis stage of healdellulose was less,but mass loss was greater than that at the pyrolysis stage of lignin.In the four-dimensional combustibility ranking of the six tree species leaves,B.platyphylla was the best ignitable,P.koraiensis was the most combustible,and P.sylvestris var.mongolica was the most sustainable and consumable.The ignitability was significantly positively correlated with pyrolysis kinetics parameters of the holocellulose,while the sustainability was negatively correlated with that of lignin.