CAJ | 학술논문

针对一台采用旋流式燃烧器的煤粉炉NOx排放质量浓度较高的问题，采用空气分级燃烧方式以降低NOx排放量，基于CFD软件平台，在额定负荷下，分别对3种不同燃尽风喷口位置的改造方案进行了炉内燃烧及污染物生成的数值模拟，并通过综合比较炉内各参数的变化确定了最佳燃尽风喷口位置．结果表明：燃尽风喷口位置的上移降低了主燃区氧气的体积分数，同时使炉膛内的最高温度降低了23～29K．燃尽风喷口位置对NO，的还原效果、出口烟气温度以及煤粉焦炭转化率的影响较大．当燃尽风喷口位置升高时，NOx质量浓度降低，炉膛出口烟气温度升高，煤粉焦炭转化率下降．经综合比较炉膛出口烟气温度、NOx质量浓度以及煤粉焦炭转化率得出，距最上层燃烧器7．7m处为最佳燃尽风喷口位置．
침대일태채용선류식연소기적매분로NOx배방질량농도교고적문제，채용공기분급연소방식이강저NOx배방량，기우CFD연건평태，재액정부하하，분별대3충불동연진풍분구위치적개조방안진행료로내연소급오염물생성적수치모의，병통과종합비교로내각삼수적변화학정료최가연진풍분구위치．결과표명：연진풍분구위치적상이강저료주연구양기적체적분수，동시사로당내적최고온도강저료23～29K．연진풍분구위치대NO，적환원효과、출구연기온도이급매분초탄전화솔적영향교대．당연진풍분구위치승고시，NOx질량농도강저，로당출구연기온도승고，매분초탄전화솔하강．경종합비교로당출구연기온도、NOx질량농도이급매분초탄전화솔득출，거최상층연소기7．7m처위최가연진풍분구위치．
To reduce the NOx emission of a coal-fired boiler with swirl burners, a retrofit scheme was pro posed by adopting the air-staged combustion mode, based on which a numerical simulation was carried out on the in-furnace combustion and pollutant formation respectively at 3 positions of OFA nozzle using CFD software platform at rated load, so as to determine the optimum position of OFA nozzle. Results show that the uplifting of OFA nozzle will reduce the O2 volumetric fraction in the main combustion zone and there- fore reduce the highest temperature in the furnace by 23-29 K; the position of OFA nozzle plays a role in influencing the NOx reduction, outlet gas temperature and coal/coke conversion rate; with the lifting of OFA nozzle position, the NO, mass concentration reduces, the outlet gas temperture rises and the coal/ coke conversion rate drops. Considering above effects comprehensively, the optimal position of OFA nozzle is finally determined as 7.7 m away from the burner of upper layer.