棉秆催化热解特性及动力学建模研究

通过不同添加剂处理棉秆的热重实验，分析NaOH、Na₂CO₃、Na₂SiO₃、NaCl、TiO₂、HZSM-5六种添加剂催化棉秆热解动力学特性，结合原料的组分分析，建立三组分独立平行一级反应热解动力学模型对试样热失重行为进行模拟，采用非线性最小平方算法求解热解动力学参数。研究发现，添加剂的加入改变了三组分动力学参数，在碱性添加剂作用下，纤维素和半纤维素热解活化能都有较大程度降低，且碱性越强，纤维素热解活化能越低，而半纤维素热解活化能越高；中性添加剂NaCl对纤维素和半纤维素热解活化能的影响不大；酸性添加剂使纤维素和半纤维素的热解活化能有所增大，但所有添加剂对木质素热解活化能的影响不明显。

Catalytic characteristic and kinetic modeling of cotton stalk pyrolysis

The kinetic characteristic of cotton stalk pyrolysis catalyzed by six kinds of additives including NaOH, Na₂CO₃, Na₂SiO₃, NaCl, TiO₂ and HZSM-5 was investigated by using the thermogravimetric analysis. The weight loss behavior was simulated by assuming the three main components of the cotton stalk sample to experience the first order parallel and independent pyrolysis reactions. The pyrolysis kinetic parameters were estimated by the nonlinear least squares algorithm. The results show that the kinetic parameters of the three components are changed by adding additives. Under the action of the alkaline additives, the activation energies of cellulose and hemicellulose can be reduced to a greater degree. The stronger the basicity of the additives, the lower the pyrolysis activation energies for the cellulose and the higher for the hemicellulose. Neutral additive NaCl has little effect on the pyrolysis activation energy. Surface acidic additives make the pyrolysis activation energies increase for the cellulose and hemicellulose. However, all the additives have no significant effects on the pyrolysis activation energies for lignin.