中蒙边境典型草原可燃物热解动力学研究

以中蒙边境(包括东乌旗、二连浩特市、新巴尔虎右旗)的草原可燃物为研究对象,利用STA 6000热重分析仪,采用热重分析法以5 ml/min,10 ml/min,20 ml/min,30 ml/min的氧气为载气,在空气气氛下,升温速率分别为40℃/min,60℃/min,80℃/min时对三个地区草原可燃物的热失重行为进行研究。利用TG-DTG曲线分析典型草原可燃物的热解特性,运用Coats-Redfern积分法和Flynn-Wall-Ozawa法得出在不同氧气浓度下的热解活化能和指前因子并求得相应参数。中蒙边境三个地区草原可燃物的热解过程分为三个阶段:水分析出阶段、快速热解阶段和碳化阶段。其中快速热解阶段的温度在270℃~450℃之间,此阶段中升温速率越快,温度滞后现象越明显;通氧速率越快,温度超前现象越明显。Flynn-Wall-Ozawa法在进行参数计算过程具有更小误差,所以较Coats-Redfern积分法更适合本次研究。热解过程及动力学参数分析表明,三个地区具有相同的热分解过程,引发火灾危险程度为:新巴尔虎右旗<东乌旗<二连浩特,因此,二连浩特市的草原可燃物较另外两地区更易燃烧,应加强草原火灾的预防和管理。

Study on the Pyrolysis Kinetics of Combustibles in the Typical Grassland on the Border Between China and Mongolia

The paper is to study the pyrolysis kinetics of fuel in China-Mongolia border grassland,reveal the combustion characteristics and change process of grassland fuel in different areas,and provide a theoretical basis for grassland fire prevention and control in the border areas.This study took grassland fuel in China-Mongolia border,specifically in East Ujimqin banner,Erenhot City,and New Barag Right Banner as the research objects,based on STA 6000 thermogravimetric analyzer,using thermogravimetric analysis to study the thermogravimetric behavior of grassland fuel in three areas under the condition of 5ml/min,10ml/min,20ml/min,30ml/min oxygen as carrier gas,under air condition,at heating rate of 40℃/min,60℃/min,80℃/min.The TG-DTG curve was used to analyze the pyrolysis characteristics of typical grassland fuel.Coats-Redfern integration method and Flynn-Wall-Ozawa method were used to obtain the pyrolysis activation energy and pre-exponential factor under oxygen concentration and obtain the corresponding parameters.The pyrolysis process of grassland fuel in three areas of China-Mongolia border is divided into three stages:dehydration,rapid pyrolysis and carbonization stages.In the rapid pyrolysis stage,temperature between 270℃and 450℃,the faster the heating rate is,the more obvious the temperature lag phenomenon is;the faster the oxygen flow rate is,the more obvious the temperature lead phenomenon is.The Flynn-Wall-Ozawa method has less errors in the process of parameter calculation,so it is more suitable for this study than Coats-Redfern integration method.Analysis of the pyrolysis process and kinetic parameters shows that the three areas have the same thermal decomposition process,and the order of fire risk from low to high is:New Barag Right Banner