炉底漏风对炉内燃烧及NOx生成排放特性的影响

干式排渣系统的冷却风会影响炉内燃烧的组织，现有研究多采用现场试验的方法，研究对象多为排烟温度或锅炉效率。以一台湿渣机改干渣机的660 MW超临界机组为研究对象，采用数值模拟的方法，研究了干渣机漏风对炉内燃烧和NO_x生成排放特性的影响，对比分析了不同炉底漏风来源时，炉膛火焰中心、飞灰含碳量、NO_x排放浓度等关键参数的变化。研究结果表明，炉底漏风量为燃尽风减量的工况对于炉内燃烧影响不明显；炉底漏风量全部或部分为燃烧器二次风减量时，随着漏风量占二次风比例的增大，主燃区氧量水平、出口飞灰含碳量、NO_x排放浓度均随之增高。从冷却风量对炉内燃烧及NO_x排放特性的角度分析了干渣机不同冷却风来源对机组运行的影响，为干式排渣机设计、改造及运行提供理论指导。

Influence of Air Leakage on the NOx Emission and Combustion Characteristics

The cooling wind of the dry slagging system will affect the burning organization in the furnace. The existing research mostly adopts the field test method, and the research object is mostly the exhaust gas temperature or the boiler efficiency. Taking a 660 MW supercritical unit of a wet slag machine to dry slag machine as the research object, the influence of air leakage from dry slag machine on combustion and NO_x emission characteristics of the furnace was studied by numerical simulation method. At the source, changes in key parameters such as furnace flame center, fly ash carbon content, and NO_x emission concentration. The results show that the air leakage at the bottom of the furnace is the same as that of the burned-out wind. The influence of the air leakage at the bottom of the furnace is not obvious. When the air leakage at the bottom of the furnace is all or part of the secondary air reduction of the burner, the air leakage accounts for the secondary air. As the proportion increases, the oxygen level in the main combustion zone, the carbon content of the outlet fly ash, and the NO_x emission concentration increase accordingly. From the perspective of the cooling air volume on the combustion and NO_x emission characteristics of the furnace, the influence of different cooling air sources of the dry slag machine on the unit operation is analyzed, which provides theoretical guidance for the design, modification and operation of the dry slag discharge machine.