帽儿山地区4种灌木热解特性研究

Study on the pyrolysis characteristics of four bushes in Maor mountain

森林火灾对森林资源的破坏性极大,通过热解技术研究森林资源自身性质,有利于对不同树种采取不同防火优先级。以黑龙江省帽儿山地区的紫丁香、长白忍冬、榆叶梅、红瑞木4种灌木为实验材料,采用热重分析法研究其热解特性和动力学特性。选取粒径为40目的实验材料,环境的升温速率为20℃/min,在氧体积分数21%的空气氛围下进行实验,采用微分法和积分法相结合进行动力学研究,根据动力学方程求算活化能和指前因子。通过模糊聚类分析对主要失重阶段的最高失重速率点的温度、主要失重阶段的活化能和热解剩余质量3个因素综合分析得到4种灌木的易燃性排序。研究结果表明:4种灌木材料的热解过程分为失水阶段,半纤维素、纤维素和部分木质素热解阶段,部分木质素及热解产物热解阶段,灰分阶段4个阶段;4种灌木主要失重阶段是半纤维素、纤维素和部分木质素热解阶段,次要失重阶段是部分木质素及热解产物热解阶段;4种灌木主要失重阶段的活化能范围为260.4351~326.1713 kJ/mol,次要失重阶段活化能范围为315.8367~425.9201 kJ/mol。4种灌木最先发生化学反应的是主要失重阶段,根据模糊聚类分析对4种灌木的易燃性进行排序,结果为:紫丁香>榆叶梅>红瑞木>长白忍冬,表明4种灌木中紫丁香最易燃,在防火期需要重点关注,长白忍冬抗火性最好,可以作为抗火性树种。

Forest fires are extremely destructive to forest resources.Using pyrolysis technology to study the nature of forest resources is beneficial for adopting different fire protection priorities for different materials.Syringa oblata Lindl,Lonicera ruprechtiana Regel,Amygdalus triloba,and Cornus alba Linnaeus in Maor mountain of Heilongjiang Province were used as experimental materials.Thermogravimetric analysis was used to study the pyrolysis and kinetic characteristics of the four bushes.The selected heating rate was 20℃/min,the particle size was 40 meshes,and the experiment was carried out in the air atmosphere with oxygen content 21%.The combination of differentiation and integration was used for kinetics research,the activation energy and pre-exponential factor were calculated according to the kinetic equation.The flammability ranking of the four bushes was obtained by comprehensive analysis of the temperature of the highest weight loss rate point in the main weight loss stage,the activation energy of the main weight loss stage and the residual mass of pyrolysis by fuzzy cluster analysis.The research results show that the pyrolysis process of four kinds of bushes is divided into four stages:water loss stage,pyrolysis stage of hemicellulose,cellulose and part of lignin,pyrolysis stage of part of lignin and pyrolysis products,and the ash stage.The main weight loss stage of the four bushes is the pyrolysis stage of hemicellulose,cellulose and part of lignin,and the secondary weight loss stage is the pyrolysis stage of part of lignin and pyrolysis products.The activation energy range of the four bushes during the main weightlessness phase is 260.4351~326.1713 kJ/mol,and the activation energy range of the secondary weightlessness phase is 315.8367~425.9201 kJ/mol.The first chemical reaction of the four bushes is the main weightless stage.The flammability of the four bushes is ranked according to the activation energy of the main weightless stage,and the results are as follows:Syringa oblata Lindl>Amygdalus triloba>Cornus alba Linnaeus>Lonicera ruprechtiana Regel.It shows that Syringa oblata Lindl among the four bushes is the most flammable,and special attention needs to be paid during the fire prevention period.Lonicera ruprechtiana Regel has the best fire resistance and can be used as a fire-resistant tree species.