旋流燃烧煤粉锅炉NO_x生成的数值模拟  

Numerical Simulation of NOx Formation in Pulverized Coal-fired Boiler with Swirl Burner

作　　者：李芳芹[1] 魏敦崧[2] 任建兴[1] 

机构地区：[1]上海电力学院,上海200090 [2]同济大学,上海200092

出　　处：《煤气与热力》2005年第4期13-16,共4页Gas & Heat

摘　　要：焦炭燃烧选取扩散-动力模型,煤热解反应采用双挥发竞争模型,气相湍流选取RNGk-ε模型,燃烧湍流选用PDF模型,采用CFD软件对1台装有32只双调风旋流燃烧器两侧墙对冲布置的1 025t/h燃煤锅炉炉内氮氧化物生成进行数值计算,研究了炉内温度场、氧浓度场以及氮氧化物浓度场的分布特性。发现三者在炉膛内均呈对称分布,燃烧区域内的温度和氮氧化物浓度较高而氧浓度较低,燃烧区域上方温度和氮氧化物浓度逐渐降低而氧浓度升高。研究了温度和空气系数对氮氧化物生成的影响,随着温度的升高,氮氧化物生成量呈升高趋势,而随着空气系数的增大,氮氧化物生成量呈降低趋势。By selecting diffusion kinetics model for coke combustion, two-competing-rates model for pyrolytic reaction of coal, RNG k-ε model for gas-phase turbulent flow, PDF model for combustion turbulent flow, the CFD software is used to numerically calculate NO_x formation in a coal-fired boiler of 1025 t/h. On the both side walls of the boiler, 32 swirl burners with double regulating air are arranged oppositely. The distribution characteristics of temperature field, NO_x and oxygen concentration field in furnace are studied, they are symmetrically distributed in furnace. In the combustion area, temperature and NO_x concentration are higher, while oxygen concentration is lower. Over the combustion (area), temperature and NO_x concentration are declined gradually, while oxygen concentration is raised. The effects of temperature and excess air coefficient on NO_x formation are discussed. The higher the temperature is, the more NO_x is formed. While the greater the excess air coefficient is, the less NO_x is formed.

关 键 词：燃煤锅炉 旋流式燃烧器 氮氧化物 数值模拟 

分 类 号：TU995[建筑科学—供热、供燃气、通风及空调工程] TK229.6[建筑科学—市政工程]