A new deep-air-staging and low-NO_x technology has been introduced to a 300 MW_e anthracite- and down-fired boiler with swirl burners. Industrial experiments were performed at different outer secondary air vane angles (defined as β) (i.e., 20°, 30°, 40°, and 50°) to evaluate the environmental and economic performance for the retrofitted boiler. Furthermore, combining with the previous investigations on the inner secondary air vane angle (defined as α), the influence degrees of β and α on anthracite combustion and NO_x emissions for the retrofitted boiler were further analyzed and compared. The experimental results revealed that the main factors affecting the ignition and the flame fullness for β and α are different. Compared with α, β had a relatively greater influence on NO_x emissions for the retrofitted boiler. Compared with the orignianl boiler, a strong reducing atmosphere was formed in the primary combustion zone for the retrofitted boiler, and for the β of approximately 30°, the arithmetic mean of NO_x emissions in the whole measurement range was reduced by 1073 mg/m³ at 6% O₂. Taking consideration of the environmental and economic effects, the optimal β for the retrofitted boiler was 20°.

中文翻译：

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对无烟煤燃烧和NO的工业实验_X排放量相对于二次旋流空气中300兆瓦_Ë深空气分级向下煤粉锅炉

一种新的深空分期和低NO _X技术已被引入到一个300兆瓦_é anthracite-和向下烧制锅炉燃烧器的漩涡。在不同的外部二次风叶片角度（定义为β）（即20°，30°，40°和50°）上进行了工业实验，以评估翻新锅炉的环境和经济性能。此外，结合先前对内部二次风叶片角度（定义为α）的研究，β和α对无烟煤燃烧和NO _x的影响程度进一步分析并比较了改装锅炉的排放。实验结果表明，影响β和α点火和火焰充满度的主要因素是不同的。与α相比，β对改装锅炉的NO _x排放影响较大。与orignianl锅炉相比，形成在用于改型锅炉的初级燃烧区较强的还原性气氛，并且对于大约30的β°，NO的算术平均值_X在整个测量范围内的排放量减少了1073毫克/米³在6％O _2下。考虑到环境和经济影响，改型锅炉的最佳β为20°。