300MW煤粉/高炉煤气混燃锅炉NO_x优化数值模拟

Numerical Simulation of 300 MW Blast Furnace Gas and Pulverized Coal Blended Combustion Boiler on the Optimizing of NO_x

利用Fluent软件对某钢厂300 MW煤粉/高炉煤气混燃锅炉进行数值模拟,探讨了燃烬风配比、高炉煤气配比、过量空气系数及运行负荷等因素对炉膛内CO浓度分布及NOx浓度分布的影响规律。研究表明:燃烬风配比增加,燃烧器附近的CO浓度峰值增加且炉膛内部的NOx浓度整体降低;高炉煤气配比增加,炉膛内部的CO浓度的峰值下降,同时NOx浓度呈整体下降趋势;随着过量空气系数增加,燃烧器上部的CO浓度均有所下降,而NOx浓度逐渐上升;运行工况对炉膛内部CO浓度的分布影响不大,随着负荷的降低,峰值略有升高,然而NOx浓度分布在燃烧器上部受负荷影响较显著,随着负荷下降,NOx浓度逐渐下降。

300 MW blast furnace gas and pulverized coal blended combustion Boiler was numerical simulated by the fluent software.The effects of OFA ratio,blast furnace gas ratio,excess air coefficient and operating duty on CO concentration distribution and NOx concentration distribution in the furnace cavity were studied.Some results and conclusions were illustrated through some curves.The more OFA ratio,the higher peak value of CO concentration in the burner area and the less NOx concentration in the whole furnace cavity;The increase of blast furnace gas ratio made the peak value of CO concentration descend and meanwhile made the NOx concentration decline integrally;The increase of excess air coefficient always can lead to the decreasing of CO concentration over the burner,and give rise to the gradual rising of NOx concentration.The effect of operating duty on CO concentration distribution of the furnace cavity is tiny.With the operating duty decreases,the peak value rises weakly.Besides,the effect of operating duty on NOx concentration distribution over the burner is obvious,the NOx concentration decreases along with the reducing of operating duty.