半纤维素高温纯蒸汽气化微观反应机理研究  

Study of the Mechanism Governing the Microscopic Gasification Reaction of a Hemi-cellulose Pure Steam at a High Temperature

作　　者：熊家佳 田红[1] 曹小玲[1] 邓胜祥[2] 

机构地区：[1]长沙理工大学能源与动力工程学院,湖南长沙410004 [2]中南大学能源科学与工程学院,湖南长沙410083

出　　处：《热能动力工程》2015年第3期467-474,501,共8页Journal of Engineering for Thermal Energy and Power

基　　金：国家自然科学基金资助项目(51276023)

摘　　要：采用密度泛函理论方法,对半纤维素的模化物木聚糖在典型温度范围(700-1 500 K)内进行了高温纯蒸汽气化反应机理研究。设计了8条反应路径,木聚糖开环形成链状结构IM1,经过脱水和降解等一系列过程最终得到2-糠醛、乙酸、甲醇、CO等产物。研究表明:在一定温度范围内,各反应路径的吉布斯自由能变随温度升高而增大,当温度超过1 300 K时吉布斯自由能开始逐渐减小;在同样温度下路径4的吉布斯自由能变小于其它路径,且路径4的反应势垒最小,为183 k J/mol,因此反应路径4是木聚糖气化的最优路径。By adopting the method in the density function theory( DFT),studied was the mechanism governing the gasification reaction of the high temperature steam of hemi-cellulose xylan in its typical temperature range( 700 ~ 1500K)which serves as the object modeled. A total of eight reaction approaches were designed and the xylan in the form of open rings formed its chain type structure IM1 and through a series of process such as dewatering and degradation etc.,2-furfural,acetic acid,methane and CO etc. products were eventually obtained. It has been found that in a certain temperature range,the Gibbs free energy variations in various reaction approaches will increase with an increase of the temperature,however,when the temperature exceeds 1 300 K,the Gibbs free energy will begin to gradually decrease. At a same temperature,the Gibbs free energy variation in the approach No. 4 is less than those of other approaches and the reaction potential barrier in approach No. 4 is the minimum,being only 183 k J / mol,hence,the reaction approach No. 4 is deemed as the optimum approach for the gasification of xylan.

关 键 词：半纤维素 密度泛函理论 高温纯蒸汽气化 微观反应机理 

分 类 号：TK61[动力工程及工程热物理—生物能]