大型循环流化床底部区域颗粒浓度波动研究

Research on Particle Concentration Fluctuation in the Bottom Zone of a Plant Circulating Fluidized Bed

在内径400 mm、高9 100 mm的大型冷态循环流化床实验装置上利用光导纤维探头研究底部区域颗粒浓度的波动行为,并采用统计方法和功率谱分析了浓度波动.结果表明,正常流化条件下,颗粒浓度标准偏差在径向上随r/R的增大而增大,而随轴向位置的增高而减小;标准偏差随颗粒循环速率的增大而增大,而随表观气速的增大而减小.分析颗粒浓度波动的功率谱发现,主频不明显,0－10 Hz范围内振幅较大.实验结果为循环流化床装置的设计、数值模拟和工程放大提供了一定依据.

The experiments were carried out in a plant circulating fluidized bed of 400 mm in diameter and 9 100 mm in height to determine particle concentration fluctuation in the bottom zone. And the data measured by optical fiber probe was systematically analyzed using statistical method and power spectrum. It is found that standard deviations increase with the increasing value of r/R in the radial direction. And standard deviations decrease with increasing height in the axial direction. At the same time,standard deviations increase with increasing solid circulation rate, decrease with increasing superficial gas velocity. Furthermore, there is not an obvious principal frequency,and concentration amplitude has peak value in the frequency range from 0--10 Hz. And the result is useful for circulating fluidized bed＇s design, numerical simulation and engineering scale-up.