加入甲烷促进选择性非催化还原反应的机理验证和分析  

Mechanism Validation and Analysis of the Selective Non-catalytic Reduction Reaction With Methane Additive

作　　者：张彦文[1] 蔡宁生[1] 

机构地区：[1]清华大学热科学与动力工程教育部重点实验室,北京市海淀区100084

出　　处：《中国电机工程学报》2008年第2期49-54,共6页Proceedings of the CSEE

基　　金：国家重点基础研究发展规划项目(973项目)(2006CB200305)。~~

摘　　要：通过敏感性和反应途径分析,修正了A机理模型的部分反应参数,并利用实验结果及文献数据进行了验证,进而利用修正后的机理模型对加入CH4的选择性非催化还原(SNCR)反应进行深入分析。分析结果表明修正后的模型可准确模拟加入CH4的SNCR反应。在SNCR反应中加入CH4,其氧化反应使得OH和HO2等基元含量增加,激发了NH3形成NH2,在较低温度下促进了SNCR反应,减少了氨泄漏。CH4与NH3的氧化过程形成竞争,导致较高喷氨量时反应温度窗口向高温拓展。对固定氮总量(nNO+nNO2+nN2O+nNH3)和nTFN+nCO的分析表明,加入250μL/L左右的CH4可起到最佳效果。加入CH4还使SNCR反应速率大大加快,从而缩短了反应时间。相对于常规SNCR反应,在合适的反应温度下,加入CH4不会使N2O、NO2的产量增加,也不会产生明显的CO,nTFN和nTFN+nCO的排放量显著减少。Some reaction parameters in the AA mechanism were modified by sensitivity and reaction path analyses. The modified mechanism was validated with experimental results and literature data, and the selective non-catalytic reduction （SNCR） reaction with methane additive was analysed using the modified mechanism. It is indicated that modified mechanism agrees well with the experimental results. Oxidation of methane increases the amount of OH and HO2 radicals which catalyse ammonia into amidogen and enhance the SNCR reaction at lower temperature. Competition of oxidation between methane and ammonia extends the SNCR temperature window to higher temperature with more ammonia. Analyses of total fixed nitrogen （nTFN=nNO＋ nNO2＋ nN2O＋nNH1 ） and nTFN＋nCO indicate that 250μL/L methane additive will achieve the best effect. Moreover, methane additive increases SNCR reaction rate so as to shorten the necessary residence time. Compared with traditional SNCR process, reaction with methane additive at appropriate temperature will not produce more nitrous oxide（N2O）, nitric oxide（NO2）, and carbon monoxide（CO）, and production of nTFN and nTFN＋nCO is decreased remarkably.

关 键 词：选择性非催化还原 甲烷 添加剂 反应机理 固定氮总量 

分 类 号：TK16[动力工程及工程热物理—热能工程]