Abstract: To investigate the characteristics of pressure fluctuations in the T-abrupt exit, the dynamic pressures of gas-solid two-phase flow in the T-abrupt exit of a CFB riser were measured in a circulating fluidized bed device with FCC catalyst by dynamic pressure sensors. The pressure fluctuations of the blind tube in T-abrupt exit were the strongest and the gas-solid two-phase flow in T-abrupt exit formed a new fluctuation source which was the result of the particles cluster turning back in the blind tube. Wavelet analysis revealed that pressure fluctuations in the T-abrupt exit mainly came from the fluctuation source in the blind tube constituting the main frequency, while the energy ratio of secondary frequency increased with increasing solids mass flux. The standard deviation of the dynamic pressures in the T-abrupt exit was linear with the solids mass flux, and in the inlet of the T-abrupt exit the linear relationship was well-defined. So the real-time solids mass flux could be characterized by the standard deviation of the dynamic pressures in the inlet of the T-abrupt exit.

Key words: circulating fluidized bed, riser, T-abrupt exit, pressure fluctuations, wavelet analysis, catalyst, two-phase flow

摘要： 针对循环流化床提升管出口T形弯头,以FCC催化剂颗粒为物料,采用动态压力传感器,对T形弯头内的气固两相流的动态压力进行了实验测量,以此分析T形弯头内动态压力的特性。实验结果表明,由于在T形弯头盲管处颗粒折返造成的冲击,形成了一个压力脉动源。小波分析表明T形弯头处的压力脉动主频来自盲管内,而次频能量所占比例随着颗粒质量流率增加而加大。T形弯头内的动态压力的标准偏差与颗粒质量流率呈线性关系,可以用于表征循环流化床内的颗粒质量流率。

关键词: 循环流化床, 提升管, T形弯头, 动态压力, 小波分析, 催化剂, 两相流