燃尽风率对锅炉燃烧特性影响的数值模拟

Effect of over fire air rate on boiler combustion performance:a numerical simulation

对某电厂330MW机组锅炉低NOx燃烧器改造后存在的受热面过热问题,通过数值模拟与试验相结合的方法,研究燃尽风率变化对炉内温度场、氧气质量浓度分布及NOx排放的影响,并将模拟数据与试验结果进行了对比.结果表明：数值模拟与试验研究结果较为吻合,燃尽风率的增加有利于降低NOx排放,但对锅炉运行的安全性和经济性会产生一定影响,综合考虑NOx排放和锅炉运行安全性,燃尽风率应控制在25%-30%.

Over burner retro high temperature occurred in heating surface of a 330 MW unit boiler after the low NOx ting. To solve this problem,the effect of over fire air （OFA） rate on temperature field,oxygen concentration distribution in furnace and NOx emission were numerically investigated, combining with experiment. The results show that,the simulation results agreed well with the experimental results. An in- crease in OFA rate was helpful to reduce NOx emissions,but had adverse effect on operation safety and e conomy of the boiler. Comprehensively considering the NOx emissions and operation safety ,the OFA rate should be controlled within the range from 25% to 30%.