Numerical Study on NO Formation in a Pulverized Coal-fired Furnace using Oxy-fuel Combustion
Computational fluid dynamics (CFD) approach was employed to numerically investigate NO formation in a 600 MW wall-fired pulverized coal-fired furnace retrofitted for oxy-coal combustion,aimed at the impacts of flue gas reycle ratio,O2 staging and recycled NO with the recycled flue gas (RFG) on NO formation and emission.An in-house CFD research code for conventional air combustion was developed and extended to simulate O2/RFG combustion with specific considerations of the change of gas properties and its impact on coal particle combustion processes.The extended De Soete mechanisms including NO reburning mechanism were applied to describe transformations of fuel nitrogen.It was shown that CFD simulation represented the significant reduction of NO formation during O2/RFG combustion compared to that during air combustion.The in-burner and particularly the infurnace O2 staging were confirmed still to play very important roles in NO formation control.Changing the recycle ratio had significant impact on the combustion performance and consequently on NO formation and emission.With the combustion performance ensured,decreasing the flue gas recycle ratio or increasing the inlet O2 concentration of combustion gas led to reduction of NO formation and emission.Although NO formation and emission was found to increase with increasing the inlet NO concentration of combution gas,CFD simulation indicated that -74％ of the inlet NO was reduced in the furnace,consistent with the experimental data reported in the literature.This demonstrated the significant contribution of reburning mechanism to the reduction of the recycled NO in the furnace.
pulverized coal-fired furnace oxyfuel combustion NO emission CFD modeling
Aiyue Zhang Yuan Chen Changdong Sheng
School of Energy and Environment,Southeat University,Nanjing 210096,China
国际会议
The 7th International Symposium on Coal Combustion(第七届国际煤燃烧学术会议)
哈尔滨
英文
621-628
2011-07-19（万方平台首次上网日期，不代表论文的发表时间）