基于烟气再循环技术降低燃气锅炉NO_(x)排放数值模拟与分析  

Numerical Simulation and Analysis of NO_(x) Reduction in Gas⁃fired Boilers Based on Flue Gas Recirculation Technology

作　　者：张子函 王清成 马月月 ZHANG Zihan;WANG Qingcheng;MA Yueyue(Shanghai Institute of Technology,Shanghai University of Applied Sciences,Shanghai 201418,China)

机构地区：[1]上海应用技术大学城市建设与安全工程学院,上海奉贤201418

出　　处：《工业锅炉》2022年第2期1-8,共8页Industrial Boilers

摘　　要：为降低燃气锅炉因为燃烧而产生的NO_(x)污染物的排放,通过对燃气锅炉二维截面建模,然后利用CFD软件,通过加载标准壁面(SWF)及可实现的Κ-ε湍流模型,非预混燃烧模型和利用稳定小火焰扩散燃烧组分,添加Chemkin化学动力学燃烧机理,模拟了燃气锅炉在不同的燃气入口间距、不同的烟气再循环率以及不同的烟气再循环组分情况下,模拟并分析出燃气锅炉炉膛内的火焰温度场、火焰外形尺寸以及燃烧过程中的氧气、二氧化碳等组分。模拟结果表明:随着烟气再循环率的上升,燃气锅炉内部的火焰温度以及火焰大小会逐渐降低,在烟气再循环率达到10%~15%时,NO_(x)的排放浓度降低为114.9 mg/m^(3),与无烟气再循环情况相比,降低了61.4%,证明了烟气再循环有利于减少热力型NOx的排放。In order to reduce the emission of NO_(x)pollutants caused by combustion of gas-fired boiler,through the two-dimensional section modeling of gas-fired boiler,and then using CFD software,by loading standard wall(SWF)andΚ-εTurbulence model,non premixed combustion model,stable small flame diffusion combustion components and Chemkin chemical kinetic combustion mechanism are used to simulate the gas-fired boiler under different gas inlet spacing,different flue gas recirculation rate and different flue gas recirculation components.The flame temperature field,flame dimension and oxygen,carbon dioxide and other components in the combustion process are simulated and analyzed.The simulation results show that with the increase of flue gas recirculation rate,the flame temperature and flame size in the gas-fired boiler will gradually decrease.When the flue gas recirculation rate reaches 10%~15%,the emission concentration of NO_(x)will be re⁃duced to 114.9 mg/m^(3),which is 61.4%lower than that without flue gas recirculation,which proves that flue gas recircula⁃tion is conducive to reducing the emission of thermal NO_(x).

关 键 词：燃气锅炉 湍流模型 非预混燃烧 烟气再循环 氮氧化物 

分 类 号：TK229.8[动力工程及工程热物理—动力机械及工程]