高浓度CO_2气氛下煤焦异相还原NO的量子化学研究  

Quantum Chemistry Research on NO Heterogeneous Reduction by Char Under High CO_2 Concentration Atmosphere

作　　者：王子剑[1] 刘豪[1] 赵然[1,2] 钟孝蛟[1] 胡翰[1] 闫志强[1] 邱建荣[1] 

机构地区：[1]华中科技大学煤燃烧国家重点实验室,武汉430074 [2]武汉纺织大学环境工程学院,武汉430073

出　　处：《燃烧科学与技术》2012年第1期79-84,共6页Journal of Combustion Science and Technology

基　　金：国家自然科学基金资助项目(51078163;51021065;50936001)

摘　　要：氧燃烧技术是一种能综合控制燃煤污染排放的新型燃烧技术,循环烟气中NOx被碳氢化合物的均相、煤焦(碳)异相还原,使得NOx排放大为降低.高浓度CO2气氛是氧燃烧技术的最大特点之一,为了研究高浓度CO2气氛下煤焦(碳)异相还原NO相关反应,采用了密度泛函计算方法B3LYP/6-31G(d),计算煤焦(碳)异相还原NO反应以及CO和O2影响NO还原过程的相关反应,优化得到反应路径上稳定点的几何构型;采用QCISD(T)/6-311G(d,p)方法计算得到了反应过程中各稳定点的能量,并计算得到活化能;使用经典过渡态理论计算反应速率常数,得出每个反应的阿累尼乌斯表达式,研究了详细反应路径和机理.初步探讨了氧燃烧方式下煤焦异相还原NO机理,获得了重要相关反应的反应路径和动力学参数;并且为进一步研究煤焦与多种气体联合作用机理提供了理论基础.Oxy-fuel combustion technology is considered as a clean coal combustion technology with a promising prospect. Because of homogeneous and heterogeneous NOx reduction process in flue gas, NOx emission is greatly reduced. Since high CO2 concentration atmosphere is one of the most important characteristics of oxy-fuel combustion technology, elemental reactions of NO heterogeneous reduction by char under high CO2 concentration atmosphere were investigated in this paper. The geometry optimizations of reactants, transition states, intermediates and prod- ucts of the reactions were studied by using density functional theory （DFT）, B3LYP, at 6-31G （d）basis function level. Based on the analysis of reaction pathways, molecular energies were calculated by a higher level ab initio method, QCISD （T）/6-311 G （d, p）, and corrected with zero point energy. The activation energies and the reaction rate constants were calculated by transition state theory （TST）, and the Arrhenius formulas of each reaction were worked out. The char-NO heterogeneous reduction mechanisms on oxy-fuel combustion were investigated in this work, and the important reaction pathways and kinetic parameters were analyzed, which provides a theoretical basis for the further study of char combustion mechanism under high CO2 concentration atmosphere.

关 键 词：NOx 煤焦 反应机理 氧燃烧 量子化学 

分 类 号：TK16[动力工程及工程热物理—热能工程]