摘要
对木屑在不同的升温速度下的热解反应动力学进行了研究。测试结果表明:不同的升温速度使生物质的热解反应机理和过程发生了变化。在4.2和40℃/min的升温速度下,两者反应的TG DSC T曲线有相似之处,均出现明显的吸热峰,而在390℃以后,升温速度为4.2℃/min时,热解反应动力学模型已经不能用传统的数学模型表示,其反应速率与升温速度显示了一个线性关系。40℃/min升温速度时,在385～490℃拐点范围内,亦不能用通常使用的数学模型公式描述;在490～700℃的范围内,用数学模型可以表示,且线性回归的相关性很好。其反应活化能为29.53kJ/mol,大大低于人们通常试验的数据(一般为70～110kJ/mol)。10和20℃/min的升温速度时,其热解反应TG DSC T曲线相近,且它们的反应动力学数学模型基本符合传统的表示方法。研究表明,不同升温速度决定了反应的过程。研究结果可以推论,快速热解反应的机理将不同于人们通常描述的步骤进行,相应的反应活化能这一重要的物理参数会发生很大变化。
This paper deals with the test results of the study on the reaction kinetics of sawdust pyrolysis.Under the condition of different temperature rising rate,the reaction mechanism and process of biomass pyrolysis are changed.For temperature rising rate of 4.2 and 40 ℃/min,both TG-DSC-T curves are similar in their endothermal peaks.For temperature rising rate of 4.2 ℃/min over 390 ℃,chemical reaction kinetics can not be expressed by traditional mathematical model and the reaction rate appears to be in a linear relation with reaction temperature.For heating rate of 40 ℃/min within the scope of turning points(at 385-490 ℃) the reaction kinetics also can not be expressed with the mathematical model formula used usually.However for reaction temperature in the scope of 490-700 ℃,the reaction kinetics can be expressed by mathematical model with very good correlation of linear regression.The reaction activation energy of E=29.53 kJ/mol is greatly lower than the data of the usual trials(generally E=70-110 kJ/mol).For temperature rising rate of 10 and 20 ℃/min,both TG-DSC-T curves of pyrolysis reaction are similar,and their (reaction) kinetics mathematical models comform to the traditional expression method basically.These research results indicated that different heating rates determine the process of reaction.It can be deduced from test results,that the mechanism and process of fast pyrolysis reaction are different from those of the usual pyrolysis reaction,and (correspondingly) the reaction activation energy,an important physical parameter for reaction,will change significantly.
出处
《林产化学与工业》
EI
CAS
CSCD
2003年第4期1-6,共6页
Chemistry and Industry of Forest Products
