循环流化床锅炉煤泥燃烧行为模型

为计算煤泥燃烧行为的运动和干燥过程,基于沿垂直方向一维运动与颗粒内部退缩蒸发界面假设建立了耦合模型,计算了不同条件下煤泥的运动和内部温度参数。结果表明,煤泥的运动过程与粒径相关,细颗粒下落后向上运动,较小颗粒到达某一位置之后稳定燃烧,较大颗粒可以落到床层表面。由于炉膛内部物料分布的影响,颗粒的稳定时间在整体下降趋势中存在一个峰值。大颗粒受到床料的影响,在床层上方速度衰减迅速,200 mm颗粒到达表面时,速度为1~2 m/s,不会对床层产生较大扰动。到达床层表面时,大颗粒仅表层被干燥,温度与中心温度具有明显差异;干燥部分占整体体积较小,如100 mm颗粒干燥层所占体积分数为3.24%,不会对于燃烧效率造成显著影响。

Model of coal slime combustion behavior in CFB boiler

In order to calculate the sports and drying process of coal combustion behavior,a model was developed to calculate the coal slime motion and the inside temperature of the combustion behavior under different conditions based on the one-dimensional vertical motion and shrinking evaporation interface assumptions.The results show that the coal slime motion is related to the particle size.Fine particles move upward after feeding,small particles are burnt stably at a certain height,while the large particles reach the bed surface.The stabilization time has a peak while decreases as the particle size increases due to the bed material distribution.The large particle velocities decrease rapidly before reaching the bed.The velocities of 200 mm particles are 1-2 m/s.The shock to boiler is not significant.Only the surfaces of the large particles have been dried with a distinct temperature difference with the cores.The dried region is only a small proportion of the particle,for example,the value of the 100 mm particle is 3.24%.Thus,it will not significantly affect the combustion efficiency.