基于空气分级的循环流化床锅炉低氮燃烧模拟  

Simulation on the Basis of Air Staged of Low Nitrogen Combustion in Circulating Fluidized Bed Boilers

作　　者：彭丹[1] 王贲[2] 李威[2] 许超 PENG Dan;WANG Ben;LI Wei;XU Chao(Power Plant Energy Conservation and Environmental Protection Engineering Technology Research Center of Henan,Zhengzhou Electric Power College, Zhengzhou 450001,China;State Key Laboratory of Coal Combustion, Huazhong University of Science & Technolog,Wuhan 430074,China)

机构地区：[1]郑州电力高等专科学校,河南省电厂节能环保工程技术研究中心,河南郑州450000 [2]华中科技大学煤燃烧国家重点实验室,湖北武汉430074

出　　处：《锅炉技术》2020年第5期30-36,共7页Boiler Technology

基　　金：国家重点研发计划资助(2018YFC1901300);河南省科技攻关项目(202102310227)。

摘　　要：针对某循环流化床锅炉实际运行中存在燃烧不均匀、局部温度高及NOx排放超标等问题,采用基于CPFD的数值模拟法对二次风系统中喷口布置、一、二次风分配及二次风配比等因素对锅炉平稳燃烧及NOx排放的影响进行分析。结果表明:二次风喷口改造产生良好的空气分级燃烧效果,NOx排放浓度由原来的270 mg/m^3降至160 mg/m^3,但炉膛温度也降低10~15 K。二次风配风方式改造表明其对稳定燃烧有较好效果,随着二次风中心风率的增加,空气分级加深,二次风的穿透能力加强,当下二次风喷口风率降至5%,中心喷口风率升为9%时,此时NOx水平降低明显,同时炉内温度场较为稳定。结合现场试验结果表明:二次风改造可达到降低氮氧化物排放的目的。CPFD calculation method of a circulating fluidizedbed boiler(CFB)was conducted to figure out the reasons for unbalanced combustion,unbalanced air distribution,and NOx excessive emissions and so on.Specific simulations on critical factors such as secondary air nozzle arrangment,primary and secondary air ratio and distribution,have been carried out to analyse the influence on combustion and NOx emission.The results indicate that the modification on secondary air produced a certain air classification combustion effect.resulting in NOx content reduction from the 270 mg/m^3 to 160 mg/m^3.However,the furnace temperature dropped by 10~15 K.The changed of secondary air distribution effectively helped to stabilize combustion.When the secondary air rate dropped to 5%,and the center nozzle air rate up to 9%,the NOx level decreased significantly,and the furnace temperature field was more stable.Combined with the results of field test,shown that the secondary air reformation can achieve the purpose of reducing nitrogen oxide emissions.

关 键 词：循环流化床 空气分级 氮氧化物 二次风 数值模拟 

分 类 号：TK229.66[动力工程及工程热物理—动力机械及工程]