Low-NO_X combustion is the main technology for reducing NO_X emission in coal-fired plants. In this work, numerical simulation was conducted on a 600-MWe down-fired lean coal boiler to study the effects of important factors on NO_X reduction, namely, the arrangements of tertiary air (TA), the jet angle of secondary air (SA), the separated over-fire air (SOFA) ratio, and the SOFA jet angle. The optimal arrangement was obtained with the original TA moved down; the jet angle of SA (A layer) at 20° (downdip); the SA (F layer) and the TA at 20° and 30° (downdip), respectively; and the SOFA set in the upper furnace, with a 20% ratio and a 30° jet angle. The NO_X emissions were reduced from 1527 mg/m³ to 773 mg/m³ in the optimized system. Meanwhile, the exhaust gas temperature decreased from 1387 K to 1369 K, and the unburned carbon content increased slightly by 0.24%, with the overall boiler efficiency kept nearly constant. The in situ measurement results are consistent with the simulation predictions.

低NO _X燃烧是减少燃煤电厂NO _X排放的主要技术。在这项工作中，数值模拟上的600兆瓦进行向下烧制贫煤锅炉来研究对NO重要因素的影响_X还原，即，三次风的（TA）的安排，二次空气的喷射角（SA ），分离的过火空气（SOFA）比和SOFA喷射角。原始TA向下移动即可获得最佳布置。SA（A层）的喷射角为20°（下倾）；SA（F层）和TA在20°和30°（下倾）；SOFA以20％的比例和30°的喷射角固定在上炉中。NO _X排放量从1527 mg / m ³降低至773 mg / m³在优化系统中。同时，废气温度从1387 K降低到1369 K，未燃烧碳含量略微增加0.24％，锅炉整体效率几乎保持恒定。原位测量结果与模拟预测一致。