采用热重-差示扫描量热-质谱(TG-DSC-MS)联用技术研究了汽车废旧轮胎在氩气气氛中的热解特性及热解气种类.结果表明,废旧轮胎在热解过程中存在一个不明显失重阶段(200~300℃)和2个明显失重阶段,分别为油类添加剂析出过程和天然橡胶热解(300~400℃)、合成橡胶热解(400~550℃)过程.随升温速率增大,轮胎起始热解温度升高,热解区间向高温方向移动,最大热解速率增加.热解过程中共检测到H2,H2O,CO,CO2,CH4,C2H2,C2H6七种热解气,其中H2O与CO存在2个析出峰,CO2存在3个析出峰,CO析出量最高.采用Ozawa峰值法与Ozawa等转化率法得到轮胎天然橡胶热解阶段的活化能介于55~60k J/mol之间,而合成橡胶热解阶段的活化能介于110~115 k J/mol之间.
Pyrolysis behaviors and pyrolysis gas of waste tires of vehicle were studied by TG-DSC-MS technique under argon atmosphere. The results show that there are three main stages during the pyrolysis of waste tires. One is a micro weight loss stage(200~300 ℃), which is the evolution of oil additives. The other two significant weight loss stages are the pyrolysis of natural rubber(300~400 ℃) and synthetic rubber(400~550 ℃). With the increasing of heating rate, the initial pyrolysis temperatures and maximum pyrolysis rates of waste tires are increased, and the pyrolysis interval also shifts to the high temperature. Seven kinds of pyrolysis gases of H2, H2O, CO, CO2, CH4, C2H2 and C2H6 were detected in the pyrolysis process. Among the seven pyrolysis gases, H2O and CO have two evolution peaks, and CO2 has three evolution peaks, and the precipitation of CO is the highest. The Ozawa peak method and Ozawa iso-conversional method were used to calculate the pyrolysis kinetics of waste tires. The results show that the activation energy of NR pyrolysis is between 55 and 60 k J/mol, and the activation energy of SR pyrolysis is between 110 and 115 k J/mol.