Ultra-supercritical double-reheat technology, as one of the most advanced coal-fired power generation technology, is an important direction for emission reduction and energy saving in the world. In this study, the numerical calculation was executed in a 660-MW ultra-supercritical double-reheat tower-type boiler under deep-air-staging conditions. The refined HCN oxidation model was adopted to substitute the default model implemented by the user-defined functions to calculate the NO_x emission. The influences of the boiler load, over-fire air (OFA) ratio, and excess air coefficient on temperature, species, and heat flux distributions were investigated. Results show that the decrement of the boiler load from boiler maximum continuous rating to 50% turbine heat acceptance gives rise to an increase of NO_x emission. The heat flux distributions along with the furnace width direction present bell shaped. When the OFA ratio rises from 17% to 43%, NO_x emission descends from 357.7 to 179.3 mg m⁻³ at the furnace outlet, and the heat flux distributions become more uniform along with the furnace width direction with lower peaks. Temperatures, species, and heat flux distributions are similar under the three different excess air coefficients. The NO_x emission is the lowest when the excess air coefficient is 1.15. The results could provide a reference for combustion characteristics optimization and hydrodynamic calculation of ultra-supercritical double-reheat tower-type boiler.

中文翻译：

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660MW超超临界双再热塔式锅炉燃烧特性及热流分布数值研究

超超临界二次再热技术作为最先进的燃煤发电技术之一，是世界减排节能的重要方向。在本研究中，数值计算是在 660 MW 超超临界双再热塔式锅炉在深空级条件下进行的。精制HCN氧化模型获得通过替代由用户定义的函数实现为计算NO的默认模型_X发射。研究了锅炉负荷、过火空气 (OFA) 比和过量空气系数对温度、种类和热通量分布的影响。结果表明，锅炉负荷从锅炉最大连续额定值到 50% 汽轮机受热率的降低导致 NO 增加。_x发射。沿炉宽方向的热流分布呈钟形。当OFA比例从17%上升到43%时，炉膛出口NO _x排放量从357.7 mg m ^-3下降到179.3 mg m ^-3，热流分布随着炉宽方向的变化更加均匀，峰值较低。在三种不同的过量空气系数下，温度、物种和热通量分布相似。当过量空气系数为 1.15 时，NO _x排放量最低。研究结果可为超超临界双再热塔式锅炉燃烧特性优化和水动力计算提供参考。