摘要
针对燃煤锅炉富氧燃烧改造的可行性以及NOx排放的问题，提出基于CFD数值模拟方法，开展1000MW双切圆式燃煤电站锅炉的富氧燃烧改造及其NOx排放的数值模拟研究．结果表明，当氧气体积分数为30％的富氧燃烧条件下模拟的炉膛温度分布、换热结果与改造前空气燃烧时相当．绝热火焰温度一致可以作为改造时氧浓度选择的依据．改造后燃料NOx、热力NOx的生成量均显著降低，总NOx生成量可达改造前的47．3％．大量二氧化碳的存在促进还原区煤焦气化反应和燃料氮的析出，削弱了NOx前驱物的氧化，促进NO还原，从而减少NOx生成量．增大燃烬风风率可降低NOx排放．再循环烟气中的NO的还原使NOx净生成量降低44．6％～71．8％．
With CFD method, the numerical simulation of retrofit of a 1 000 MW ultra-supercritical boiler to oxy-fuel combustion and the NOx emission were carried out. The results show that, the temperature gra- dient and heat flux of the furnace are mostly consistent with that of before retrofit under the oxy-fuel com- bustion with 30% oxygen. Oxygen concentration can be decided when the adiabatic flame temperature of furnace after retrofit is same as that of before retrofit. Both the fuel NO, and thermal NOx decrease re- markably and the total NO, amount after retrofit is reduced to 47.3 % of the reference boiler. The decrease of fuel NOx is majorly attributed to the enhancement of coal char gasification and the release of fuel nitro gen during the fuel rich zone, which resulted from the high CO2 concentration. Ehancing the the ratio of o- ver fire air （OFA） would lower the NOx emission. The reduction of recycled NO in flue gasdecreases the net amount of NO by 44.6% ～71.8%.
出处
《浙江大学学报（工学版）》
EI
CAS
CSCD
北大核心
2014年第11期2080-2086,共7页
Journal of Zhejiang University：Engineering Science
基金
国家"973"重点基础研究发展规划资助项目(2012CB214906)
