风量配比影响循环流化床锅炉燃烧特性研究

Study on the Combustion Characteristics of the Circulating Fluidized Bed Boiler Influenced by Air Volume Ratios

摘要: 循环流化床(CFB)锅炉因其燃烧效率高、燃料适应性好和排放污染少等优点得到了广泛的应用。本文对某240 t/h循环流化床锅炉进行了数值模拟研究，分析改变一二次风配比对内部流动和燃烧特性的影响，结果表明：一次风所占比例θ过小，炉膛内部流化效果差；一次风所占比例θ过大，不能为炉膛中心的燃烧及时供氧。一次风占比θ = 0.55时(工况三)能得到较均匀的床料和温度场分布，同时NO_x出口质量浓度最低。

Abstract: Circulating fluidized bed (CFB) boilers have been widely used due to the high combustion efficiency, good fuel adaptability and low pollutant emission. This paper conducted a numerical simulation analysis on a 240 t/h circulating fluidized bed boiler to analyze the influence of changing the ratio of primary and secondary air on the internal flow and combustion characteristics. The results show that the small proportion of primary air θ resulted in poor effect of fluidization inside the furnace; too large proportion of primary air θ cannot provide oxygen for the combustion in the center of the furnace timely; when the proportion of primary air θ is 0.55 (Condition III), the bed material and temperature distributions are even, and NO_x concentration at the outlet is the lowest.