中低温环境下竹材的热解动力学研究

Kinetics of Bamboo Pyrolysis at Middle-low Temperature

竹材的热解过程主要分为3个阶段,每个阶段对应了不同的化学物理变化和不同的热效应,210～250℃是竹材热解的主要阶段,物质挥发分大量析出也集中在这个阶段。整个热解过程是由竹材中半纤维素及纤维素等成分的热解过程叠加组成。竹材活化能很大,表明竹材的热解很难进行,需要在较高的温度下,提供足够的能量时,热解才能发生。根据竹材热解速率方程导出线性热解动力学方程,并通过计算求出了竹材各个阶段的频率因子和活化能,竹材的热解反应可以用一个一级反应过程来描述。

Through the experiment, the following results can be obtained. Firstly, bamboo pyrolysis process can be divided into three phases, each corresponding to different chemical physical changes and different thermal effects; pyrolysis at the temperature of 210- 250℃ is the main phase of the bamboo sample, during which a large number of volatile substances are released, and the whole bamboo pyrolysis process is composed of pyrolysis processes of hemicellulose and cellulose. Secondly, for great activation energy of bamboo, its pyrolysis process can only occur provided with high temperature and sufficient energy. Finally, according to the bamboo pyrolysis rates at different points of time, a linear thermal kinetics equation is derived, and the frequency factors and the activation energy of various stages are calculated; and the first order reaction can be used to describe the bamboo pyrolysis process.