空气分级与偏转二次风联用对炉膛燃烧特性的影响  

The Effect to Furnace Combustion Characteristic under Different OFA Rate and Deflected Secondary Air

作　　者：唐昭帆 卢玫[1] 王克[2] 刘仲然 

机构地区：[1]上海理工大学能源与动力工程学院,上海200093 [2]上海发电设备成套设计研究院,上海200240

出　　处：《锅炉技术》2016年第6期41-48,共8页Boiler Technology

基　　金：国家自然科学基金资助项目(51176126)

摘　　要：运用CFD软件对某210 MW煤粉锅炉的燃烧过程进行三维数值模拟,采用空气分级燃烧技术,研究不同空气分级深度及偏转二次风对锅炉的燃烧情况及NOx排放的影响,同时引入“敏感性指数”,分析了不同空气分级深度下联用偏转二次风前后对锅炉运行的影响程度。结果表明：单独采用空气分级和偏转二次风均能降低NOx排放,二者联用时空气分级起主导作用,NOx排放降低25%~28%;在不同空气分级深度下联用偏二次风措施对炉内燃烧前后影响程度不同,温度场与组分场出现较为相同的影响规律,在一定燃尽风率区间,存在对应（温度、组分）敏感性系数最大的燃尽风率,敏感性指数随燃尽风率的增加呈先增加后减小的变化趋势,即影响程度先增强后减弱;联用偏转二次风改善炉内结渣和高温腐蚀的效果随燃尽风率先增强后减弱,燃尽风率在18%~25%时效果较好,但导致飞灰含碳率显著增加。By using the CFD software, numerical simulation was taken on a 210 MW tangentially fired boiler. Air staging and deflected secondary air was taken on the combustion process . The furnace combustion characteristic and NOx emission wsa investigated under different OFA rate and deflected secondary air, sensitivity exponent was introduced to analyze the effect of boiler operation under different OFA rate before and after combining with the method of deflected secondary air. Results show that air staging and deflected secondary air method can respectively NOx emission, but air staging plays the leading role, the NOx emission decreased almost 25% to 28%; The effect degree to the combustion is distinct before and after combining with deflected secondary air under different OFA rate. The change of temperature and species field show a similar law, with the increase of OFA rate, the sensitivity exponent firstly increase and then decline ; when combine with deflected secondary air, the improved degree of slagging and high temperature corrosion in the furnace are first strengthen and then weaken along with the increasing OFA rate; We can get better relief at the OFA rate of 18% -25 %, whereas the mechanical incomplete efficiency increased.

关 键 词：燃尽风率 偏转二次风 敏感性指数 NOx 结渣 飞灰含碳率 

分 类 号：TK229.6[动力工程及工程热物理—动力机械及工程]