半纤维素模化物热裂解动力学研究

在热重红外联用系统中对生物质的主要组分半纤维素的模化物进行了热裂解动力学研究．在用红外压片微观结构分析方法验证木聚糖典型结构模型的基础上,得到不同升温速率下的热重曲线表明,随着升温速率的增加,各个阶段的起始和终止温度向高温侧轻微移动,主反应区间加宽以及炭产量逐渐增加;计算得到的木聚糖两阶段活化能分别为118．59 kJ／mol和66．69 kJ／mol．与纤维素热解气的联机红外分析谱图相比可知,木聚糖热解析出气体过程复杂,其中CO在全过程都有析出,而CH4主要来源于一次挥发分的二次分解．

Kinetic Research on Pyrolysis of Model Compound of Hemicellulose

Kinetic research on the pyrolysis of model compound of hemicellulose was carried out in TGA-FTIR system. The typical microstructure of model compound was well verified by infrared analysis coupled with tabletting pretreatment. Experimental result shows that TG and DTG curves move slightly towards higher temperature with the increase of heating rate, while the main reaction area widens and the char yield rises. Xylan pyrolysis was divided into two stages, corresponding with 118. 59 kJ/mol and 66. 69 kJ/mol for activation energy respectively. Compared with cellulose pyrolysis, online infrared analysis shows that the volatile produced in the xylan pyrolysis has more complicated composition distribution. CO appeared to release out during the whole pyrolysis process, while CH4 was mainly produced by secondary cracking of primary volatile.