基于简单碰撞理论的生物质焦炭气化反应的活化能  

Gasification Activation Energy of Biomass Chars Based on Simple Collision Theory

作　　者：邵振华[1,2] 汪小憨[1] 曾小军[1] 吴勇[2] 

机构地区：[1]中国科学院广州能源研究所,广东广州510640 [2]中国科学院大学,北京100049

出　　处：《过程工程学报》2015年第4期599-606,共8页The Chinese Journal of Process Engineering

基　　金：国家自然科学基金资助项目(编号:51276184);国家重点基础研究发展规划(973)基金资助项目(编号:2011CB201501)

摘　　要：利用热重分析仪在800?1000℃及750?1000℃下分别对11种生物质原焦及6种生物质脱灰焦进行了CO2等温气化实验,用碳转化率x?0.2时的瞬时气化反应速率rc,0.2对反应速率rc进行无量纲化处理;根据简单碰撞理论,推导得出了生物质焦炭气化反应速率的表达式,求取了17种生物质焦炭气化反应的活化能;结合催化理论与简单碰撞理论建立了生物质焦炭气化反应活化能的经验预测模型.结果表明,转化率达0.2后,各焦炭不同温度下无量纲气化反应速率曲线基本重合,表明不同温度下焦炭微观结构在转化过程中具有基本相同的演变规律.各焦炭的活化能与催化剂所占据的活性位比例存在良好的对数关系.忽略催化效应的影响,焦炭本征气化反应的活化能趋于某一定值,约为254.35 k J/mol,而完全催化反应活化能约为66.02 k J/mol.The isothermal gasification of eleven raw biomass chars and six acid-washed biomass chars was performed under CO2 atmosphere, using a thermo-gravimetric analyzer （TGA） over the temperature ranges of 750- 1000 ℃ and 800- 1000 ℃, respectively. The dimensionless procedures of rc by using rc,0.2 were made. In 750-900 ℃ for raw chars and 800-1000 ℃ for acid-washed chars, the curves of dimensionless gasification reaction rate with carbon conversion rate for every char are overlapped at different temperatures after the carbon conversion rate reaches 0.2, which shows the gasification rates may be controlled by the similar evolution rules. Based on the simple collision theory （SCT） of chemical reaction kinetics, the kinetic rate expression of biomass chars during gasification reaction process was derived and activation energy of seventeen biomass chars was calculated. Combined with the catalysis theory, the empirical prediction model of activation energy for biomass chars was deduced on the basis of SCT. The results show that there is a good logarithmic relationship between the activation energy and the proportion of active sites occupied by the catalysts. It can be predicted that the intrinsic activation energy of the biomass char may tend to a certain value 254.35 kJ/mol if the catalytic effect of the metallic element is ignored, and the activation energy of the biomass char is about 66.02 kJ/mol for fully catalytic reaction.

关 键 词：生物质 焦炭 CO2气化 简单碰撞理论 活化能 模型 

分 类 号：TK6[动力工程及工程热物理—生物能]