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利用热重分析在不同升温速率和氮气气氛下对核桃壳的热失重行为进行研究。根据热重实验数据,采用4种热分析动力学方法(Coats-Redfern法、Doyle法、Ozawa法和DAEM模型),计算核桃壳热解反应活化能E、反应级数n及频率因子A,并进行比较。结果表明:采用不同的动力学分析处理方法,得出的热解动力学参数不同。利用Coats-Redfern法,核桃壳在热解主要阶段(失重10%～95%)可由一段一级反应过程描述,升温速率20K/min时活化能为55.37kJ/mol。Doyle法和DAEM模型得到的结果较为接近,Ozawa法求得的活化能值最高。核桃壳热解包含分子键能断裂的一系列复杂、连续反应过程,并获得核桃壳的热解反应活化能随失重率的变化曲线。
Thermogravimetric analysis was used to study the thermal weight loss behavior of walnut shells under different heating rates and nitrogen atmosphere. According to the thermogravimetry data, four kinds of thermal analysis kinetics (Coats-Redfern method, Doyle method, Ozawa method and DAEM model) were used to calculate the activation energy E, reaction order n and frequency factor A of walnut shell pyrolysis reaction Compare. The results show that the kinetic parameters of pyrolysis are different with different kinetic analysis and treatment methods. According to the Coats-Redfern method, walnut shell can be described by a first-order reaction process in the main stage of pyrolysis (weight loss 10% -95%). The activation energy is 55.37kJ / mol at a heating rate of 20K / min. The results obtained by the Doyle method and the DAEM model are similar, and the Ozawa method obtains the highest activation energy value. The pyrolysis of walnut shell contains a series of complex and continuous reaction processes for the molecular bond to be broken, and the activation energy of the pyrolysis reaction of the walnut shell changes with the weight loss rate curve.