甲烷分级MILD燃烧方式下NO的减排特性研究  

NO Emission Characteristics of Methane Staged MILD Combustion

作　　者：任豪 史炳 徐顺塔 黄璞 谢逸豪 涂垚杰 刘豪[1] REN Hao;SHI Bing;XU Shunta;HUANG Pu;XIE Yihao;TU Yaojie;LIU Hao(State Key Laboratory of Coal Combustion,Huazhong University of Science and Technology,Wuhan 430074,China)

机构地区：[1]华中科技大学煤燃烧国家重点实验室,武汉430074

出　　处：《工程热物理学报》2022年第12期3383-3392,共10页Journal of Engineering Thermophysics

基　　金：国家自然科学基金项目(No.51876074)。

摘　　要：本文提出将常规的分级燃烧与新型低氧稀释燃烧(MILD)相结合以实现天然气燃烧时NO的超低排放控制,基于化学动力学分析软件CHEMKIN构建了串联PSR反应器模型,考察了分级配比、当量比、进口温度、氧浓度对空气、燃料分级MILD燃烧方式下NO排放的影响规律,通过路径分析与敏感性分析探讨了MILD燃烧耦合分级燃烧前后NO化学反应路径的异同。结果表明:MILD燃烧耦合分级燃烧后能够进一步降低NO的排放,在基准计算工况下燃料、空气分级MILD燃烧方式下NO的排放较之MILD燃烧分别降低了46%和15%。分级燃烧中一次风/二次风、一次燃料/二次燃料的配比对NO排放浓度的影响呈非线性,在分级MILD燃烧方式下当二次风量占比、二次燃料量占比分别约为50%和30%时NO排放浓度最低。分级MILD燃烧相对于MILD燃烧改变了NO生成路径的贡献率,表现为N_(2)O路径作用增强,快速型路径的作用减弱,特别是燃料分级MILD燃烧方式下快速型路径作用减弱更为显著。To achieve ultra-low NO emission during natural gas combustion,the technology combination of fuel-staged or air-staged combustion and moderate and intense low-oxygen dilution(MILD)combustion is proposed,and the reaction network model of PSR is constructed with the aid of the CHEMKIN-Pro software.The effects of staging ratio,equivalent ratio,inlet temperature,and oxygen concentration on NO emission under air-staged and fuel-staged MILD combustion are investigated,and simultaneously,the similarity and difference of the NO reaction paths in MILD combustion between with and without fuel-staged/air-staged combustion are discussed by both pathway analysis and sensitivity analysis.The results show that the further NO emission reduction for MILD combustion can be realized by combining the fuel-staged/air-staged combustion.Compared to that under MILD combustion,the NO emission at the reference condition is reduced by 46% and 15% under fuel-staged and air-staged MILD combustion,respectively.In staged MILD combustion,the NO emission as a function of the primary air/secondary air ratio and the primary fuel/secondary fuel ratio presents a nonlinear correlation,and the lowest NO emission level is reached at the secondary air ratio of 50% and the secondary fuel ratio of 30%,respectively.Fuel-staged/air-staged MILD combustion behaves differently in the contribution of NO formation routes compared to MILD combustion.The N_(2)O route is enhanced and the prompt route is weakened when MILD combustion is coupled with fuel-staged/air-staged combustion,and particularly,the latter is more pronounced under fuel-staged MILD combustion.

关 键 词：MILD燃烧 燃料分级 空气分级 NO排放 NO生成路径 

分 类 号：TK16[动力工程及工程热物理—热能工程]