烟气再循环对燃烧过程NO生成的作用机理研究  

Mechanism study on effect of flue gas recirculation on NO formation during combustion process

作　　者：王志宁 蔡晋 张扬[2] 弋治军 吕俊复 张海[2] WANG Zhining;CAI Jin;ZHANG Yang;YI Zhijun;LYU Junfu;ZHANG Hai(Shanxi Research Institute for Clean Energy,Tsinghua University,Taiyuan 030024,China;Key Laboratory for Thermal Science and Power Engineering of Ministry of Education,Department of Energy and Power Engineering,Tsinghua University,Beijing 100084,China;Sichuan Chuanguo Boiler Co.,Ltd.,Chengdu 610400,China)

机构地区：[1]清华大学山西清洁能源研究院,山西太原030024 [2]清华大学能源与动力工程系(热科学与动力工程教育部重点实验室),北京100084 [3]四川川锅锅炉有限责任公司,四川成都610400

出　　处：《热力发电》2021年第3期27-33,共7页Thermal Power Generation

基　　金：山西省科技成果转化引导专项(201904D131068);四川省科技计划项目(2018JZ0021&2019YFS04976)。

摘　　要：烟气再循环引起燃烧温度、氧体积分数和停留时间的变化,从而影响燃烧过程NO的生成。本文使用全混流反应器模型结合化学反应动力学机理开展计算,研究烟气再循环对CH4燃烧过程NO生成的影响,着重分析烟气再循环引发的温度和氧体积分数降低以及停留时间变化3种机制对NO生成的影响规律。结果表明:10%的烟气再循环率可降低40%~60%的NO生成量,烟气再循环率大于30%时,烟气再循环率的提高对NO生成的抑制作用十分有限;不同过量空气系数条件下,NO生成的路径不同;烟气再循环引发的温度降低对NO的减排起到决定性作用,而其引发的氧体积分数降低对NO的减排起到次要作用;采用烟气再循环技术结合停留时间的合理控制,能够有效地抑制CH4燃烧过程NO的生成。Flue gas recirculation(FGR)induces the change of combustion temperature,oxygen volume fraction and residence time,thus to affect the NO formation during the combustion process.By using the perfectly-stirred reactor computations with detailed chemical kinetics,this paper numerically studies the effect of FGR on NO formation during CH4 combustion.The FGR induced temperature and oxygen concentration reduction and residence time variation were particularly considered.The results showed that,10%of the FGR rate resulted in a significant NO reduction by 40%~60%,while the NO suppression effect of FGR became limited when the FGR ratio exceeded 30%.The NO formation pathways differed at varied excess air ratios.The FGR induced temperature reduction dominated the overall NO reduction,while the reduced oxygen concentration played a minor role.The NO formation during the CH4 combustion could be effectively inhibited if FGR was adopted with proper residence time control.

关 键 词：NOx 甲烷 烟气再循环 化学反应动力学 数值模拟 全混流反应器 

分 类 号：TK16[动力工程及工程热物理—热能工程]