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JOURNAL OF ZHEJIANG UNIVERSITY (ENGINEERING SCIENCE)
    
Numerical simulation of NOx emission from a 1 000 MW boiler retrofitted to oxy-fuel combustion
YOU Zhuo1, WANG Zhi-hua1, ZHOU Zhi-jun1, HU Xin1, ZHU Yan-qun1, ZHOU Jun-hu1, CEN Ke-fa1
1. State Key Laboratory of Clean Energy Utilization, Zhejiang University, Hangzhou 310027, China
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Abstract  

 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 gradient and heat flux of the furnace are mostly consistent with that of before retrofit under the oxy-fuel combustion 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 NOx and thermal NOx decrease remarkably and the total NOx 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 nitrogen during the fuel rich zone, which resulted from the high CO2 concentration. Ehancing the the ratio of over 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%.



Published: 01 November 2014
CLC:  TK 229  
Fund:  

游卓(1987-),男,博士生,从事富氧燃烧的研究.E-mail:cws020@zju.edu.cn

Cite this article:

YOU Zhuo, WANG Zhi-hua, ZHOU Zhi-jun, HU Xin, ZHU Yan-qun, ZHOU Jun-hu, CEN Ke-fa. Numerical simulation of NOx emission from a 1 000 MW boiler retrofitted to oxy-fuel combustion. JOURNAL OF ZHEJIANG UNIVERSITY (ENGINEERING SCIENCE), 2014, 48(11): 2080-2086.

URL:

http://www.zjujournals.com/eng/10.3785/j.issn.1008-973X.2014.11.0241 000     OR     http://www.zjujournals.com/eng/Y2014/V48/I11/2080


MW燃煤锅炉富氧燃烧改造及NOx排放的数值模拟

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1 000 MW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%.

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