三次风对四角切圆锅炉燃烧和NO_x排放的影响  

Tertiary-air Effects on Combustion and NO_x mission in Tangentially Fired Furnace

作　　者：苟湘[1] 周俊虎[1] 周志军[1] 杨卫娟[1] 刘建忠[1] 岑可法[1] 

机构地区：[1]能源清洁利用国家重点实验室(浙江大学),浙江省杭州市310027

出　　处：《中国电机工程学报》2008年第8期7-12,共6页Proceedings of the CSEE

基　　金：国家杰出青年科学基金项目(50525620);国家重点基础研究发展规划基金项目(2006CB200303)~~

摘　　要：针对国内某热电公司410t/h四角切圆燃烧锅炉,基于CFD软件平台,对在额定负荷下单磨、双磨和无磨3种不同运行方式炉内的流动、燃烧及污染物生成进行数值模拟计算。计算结果表明,无论是单磨、双磨还是无磨运行,炉内最高温度均出现在燃烧器区域,温度分布与各组分浓度分布有着对应关系,高温区对应CO高浓度区和CO2,O2低浓度区。炉膛出口NOx浓度的高低顺序是:无磨最高,单磨次之,双磨最低。其主要原因是单磨运行形成的空气分级燃烧使得主燃烧区达到低氧燃烧,以及三次风含煤粉的再燃作用;双磨运行三次风量和含粉量更多,空气分级作用和再燃作用更强。炉膛出口烟温的高低顺序是:双磨最高,单磨次之,无磨最低。3种运行状态下的燃尽过程中HCN和焦炭N的氧化使得NO在炉膛高度沿程均有上升趋势。工程实践表明,数值计算结果与实际运行数据吻合良好。Numerical simulation on the flow, combustion and contamination generation process under the three different conditions： single-mill, double-mills and non-mill, with the rated load in a 410 t/h tangentially fired furnace in a domestic thermal power plant was performed with CFD software platform. The numerical simulation shows that no matter what mill is used, the highest temperature is in the burner zone, the temperature distribution has a corresponding relationship with the concentrations of the components, and the high temperature zone is characterized by high carbon monoxide concentration, low carbon dioxide and low oxygen concentration. The NOx concentration at the outlet of the furnace is the highest with non-mill, the second highest with single-mill and the lowest with double-mills, The main reason is that the staged-air combustion formed by single-mill makes the main combustion zone lack of oxygen and the coal in tertiary-air reburns, As the volumes of tertiary-air and coal are more with double-mills than with single-mill, staged-air and reburning become more effective, The outlet temperature of the furnace is the highest with double-mills, the second highest with single-mill and the lowest with non-mill. The NO concentration increases with the furnace height during the burnout process as HCN and Char-N are transformed to NO in all three operation conditions, Engineering testing shows that the results from numerical simulation are in conformity with real operation condition.

关 键 词：热能动力工程 三次风 四角切圆锅炉 NOx 数值模拟 

分 类 号：TK223[动力工程及工程热物理—动力机械及工程]