800MW旋流对冲燃烧锅炉低NOx改造的数值模拟

针对某800MW超临界锅炉NOx排放量较高的问题，设计了配风方式不同的3种工况．利用CFD软件，对3种工况进行了炉内燃烧、传热及污染物排放等方面的数值计算，并分析了炉内的温度、NOx及cO组分的分布情况．结果表明：计算结果与实测数据吻合较好，空气分级燃烧使主燃区温度降低，CO体积分数升高，N0x质量浓度明显降低；燃尽风对燃料的燃尽率和炉膛出口烟温产生了不利影响，从而影响机组的经济性和安全性．通过对各个工况燃料的燃尽率及炉膛出口烟温进行综合比较分析，得出工况3为较理想的改造方案．

Numerical Simulation on an 800 MW Swirl-opposed Firing Boiler Retrofitted for Low NOx Emission

According to the problem of high NOx emission existing in an 800 MW supercritical boiler, retro fit schemes with three air distribution modes were designed, based on which the infurnace combustion, heat transfer and NOx emission were numerically simulated using CFD method, while the temperature field, NOx concentration distribution and CO concentration distribution analyzed. Results show that the calculated results agree well with actual measurements. In the modes of stagedair combustion, the tem perature reduces in primary combustion zone, where the CO concentration rises and the NO, emission drops significantly. Overfire air may have unfavorable influence on the burnoff rate and outlet gas tem perature, which will reduce the security and efficiency of the unit. The results of comprehensive compari son and analysis on the burnoff rate and outlet gas temperature prove the retrofit scheme with air distribu tion mode three to be the most optimal one.