Modelling NO formation in a swirling pulverized coal flame

✍ Scribed by S.P. Visona; B.R. Stanmore

• Book ID: 104107827
• Publisher: Elsevier Science
• Year: 1998
• Tongue: English
• Weight: 925 KB
• Volume: 53
• Category: Article
• ISSN: 0009-2509
• DOI: 10.1016/s0009-2509(97)00407-7

✦ Synopsis

Nitric oxide (NO) concentrations in a swirling pulverized coal flame were predicted from a mathematical model and compared with experimental measurements. The model consisted of a two-dimensional, axi-symmetric parent CFD code combined with a (\mathrm{NO}{x}) post-processor. Both thermal and fuel (\mathrm{NO}) are included in the (\mathrm{NO}{x}) chemistry. The parent code is used to calculate the combustion aerodynamics within the flame, while the (\mathrm{NO}{x}) (postprocessor) model predicts the local concentrations of (\mathrm{HCN}, \mathrm{NH}{3}) and (\mathrm{NO}). The volatile nitrogen is released either as (\mathrm{HCN}) or (\mathrm{NH}{3}), depending on its functional form in the coal. Several models studying the conversion of char nitrogen to NO are tested, as well as the effect of a hydrocarbon reburn mechanism. The experimental data were obtained from a swirling pulverized coal flame (aerodynamically air staged burner) operated at the International Flame Research Foundation. A sensitivity analysis on the primary components of the (\mathrm{NO}{x}) chemistry is included. When the only reactions considered were those involving (\mathrm{HCN}) and NO, the NO concentrations were underpredicted. The full (\mathrm{NO}{x}) chemistry model was able to achieve good (\mathrm{NO}) predictions by including ammonia as a (\mathrm{NO}{x}) precursor and incorporating a hydrocarbon mechanism to recycle NO to HCN. (C) 1998 Elsevier Science Ltd. All rights reserved.