FCCU立管内催化剂流动的脉动压力分析

Analysis of Pressure Fluctuations of Catalyst Powder Flowing in the Standpipe of FCCU

针对FCCU立管存在的振动问题,在大型实验装置上对150mm×9000mm立管内颗粒下行流动的压力脉动信号进行了测量,并对脉动压力信号进行相干特性分析,探讨了脉动压力的形成和传递特性。实验结果表明,立管内催化剂颗粒下行过程具有很强的动态特性,表现为脉动压力。立管内呈稀、密两相共存的流态时,稀相部分的脉动压力来源于入口,向下传递,密相部分的脉动压力来源于出口,向上传递;当立管浓相输送流态时,脉动压力主要是进口处进料、下行颗粒浓度变化和下行颗粒对气体压缩的结果,向下传递。脉动压力中频率低于0.3Hz部分形成了立管振动的振源。

For studying the vibration in FCCU standpipe because of particle flow, an experiment was carried out on the pressure dynamic behavior of down-flow of FCC catalysts in a standpipe with diameter of 150 mm and height of 9000 mm. Time series of pressure fluctuations were recorded at different axial measurement points in a standpipe at solids mass fluxes of 50 kg/（m2.s） and 395 kg/（m2. s）. With the coherence between measurement points, the pressure fluctuation forming and transferring were demonstrated. The results indicated that the catalyst particle down-flow in the standpipe is of pressure fluctuation characteristics. When two flow regimes were coexisting in the standpipe, the pressure fluctuations in the upper dilute-phase part originated from the inlet and transferred downward, and in the bottom dense-phase part from the outlet and transferred upward. When there was the dense-phase conveying regime in the standpipe, the pressure fluctuations originated from the inlet and developed during FCC catalysts flowing downward. The pressure fluctuation with the frequency of lower than 0.3 Hz was the cause of the standpipe vibration.