稻秆慢速热解的需热量及动力学分析

Caloric requirement and kinetic analysis of rice straw during slow pyrolysis

应用热重-差式扫描(TG-DSC)同步热分析仪进行稻秆的热解实验,通过对DTG和DSC曲线的对比分析,详细探讨了稻秆的基本热解过程;以440 K为临界温度,将实验曲线转换为干稻秆DSC曲线,升温速率β为10,15,20和30 K/min时,干稻秆的热解净热效应分别为878,836,770,841 kJ/kg;采用Coats-Redfern积分法进行动力学分析,基于典型固态反应动力学机理模型,按最小二乘法原理确定A2模型为最佳动力学机理模型。结果表明,随着升温速率的增加,稻秆试样的活化能增加。同时,稻秆热解符合2段机理模型。

Pyrolysis experiment of rice straw was made with TG-DSC simultaneous thermal analyzer and the basic pyrolysis process was discussed by comparing DTG and DSC curves. The experimental curves were changed into DSC curves of dry rice straw when critical temperature was 440 K. The net heat is 878, 836, 770, 841 kJ/kg respectively with corresponding heating rate β of 10, 15, 20, 30 K/min. Integration method Coats-Redfern was used in kinetic analysis. Based on typical solid-phase reaction kinetic mechanism model, A2 model was determined as the optimal model by using least square method. The results show that the activation energy of rice straw increases with the increase of heating rate, and the pyrolysis of rice straw can be described by using two-stage model.