气-液-固三相流化床冷态实验

Cold Model Experiment of Gas-Liquid-Solid Three-Phase Fluidized Bed

以氮气为气相、蒸馏水为液相、铜粉为固相构建了的气-液-固三相流化床冷态实验装置,流化床反应器内径为50 mm、高为500 mm.采用Hilbert-Huang Transform分析了布风板上表面处压力脉动信号,考察了布风板压差和床内两固定测点间压差随气体流速的变化关系,使用降速法得到了气-液-固三相流化床的最小流化速度,并通过同步图像采集验证了该最小流化速度.结果表明:气体流速为14.85 mm/s时,固体颗粒之间碰撞剧烈,气、液、固三相混合均匀;随着气体流速的增加,两固定测点间压降呈现先降低,后增加,最后又降低的变化趋势;气-液-固三相流化床的最小流化速度约为17.4 mm/s.

A gas-liquid-solid three-phase fluidized bed with inner diameter of 50 mm and height of 500 mm is established by using nitrogen as gas phase,distilled water as liquid phase and copper powder as solid phase. Pressure fluctuation signals obtained in the region upon the gas distributor are analyzed by Hilbert-Huang Transform method. The effects of gas flow rate on gas distributor pressure drop and differential pressure between two fixed measure points are studied. Minimum fluidization velocity of the three-phase fluidized bed is obtained from cold model experiments and further confirmed by high speed photography. The results show that solid particles strike each other violently with the gas flow rate of 14. 85 mm / s. Gas phase,liquid phase and solid phase mixes well under such gas flow rate. With the increase in gas flow rate,differential pressure between two fixed measure points decreases at first,and then increases,and decreases at last. The minimum fluidization velocity of the three phase fluidized bed is determined as 17. 4 mm / s and finally is verified by high synchronous image acquisition.