湿颗粒的振动流化特性实验研究

Experimental study on vibrating fluidization characteristics of wet particles

在床体尺寸为140 mm×70 mm×600 mm的振动流化床中开展了湿颗粒振动流化特性实验,研究了振动强度Γ(0~1.2)、含液量W(0~6.8%)、粒径dp(1.0~2.6 mm)对D类湿颗粒振动流化特性(流型、床层压降、最小流化速度)规律的影响.结果表明:湿颗粒振动流化床可以显著改善床层内的沟流现象,使流化更稳定.降速过程中,固定床阶段湿颗粒振动床床层压降ΔP明显大于湿颗粒普通流化床压降,而在第2流化阶段两者压降相近;同时,湿颗粒振动流化床压降随含液量的增加先降低后增加.在湿颗粒振动床中,随着振动强度的增大,最小流化速度减小;随着含液量上升,最小流化速度先增加后下降;随着颗粒粒径的增大,最小流化速度增加.最后得出了D类湿颗粒振动流化床最小流化速度的计算关联式.

Experimental studies on vibrating fluidization characteristics of wet particles are carried out in a vibrating fluidized bed with a bed（ 140 mm × 70 mm × 600 mm）. The effects of vibration intensity Γ（ 0 to 1. 2）,liquid content W（ 0 to 6. 8%） and particle size d_p（ 1. 0 to 2. 6 mm） on the fluidization characteristics were studied,including flow pattern,pressure drop and minimum fluidization velocity. The study results show that the vibrating fluidized bed of w et particles can improve the channeling of the wet particle fluidization and make the fluidizations more stable. During the deceleration process,the pressure drop of wet particles in the vibrating fluidized bed is observably lager than that of the ordinary fluidized bed at the fixed bed stage. How ever,at the second fluidization stage,pressure drops of the two fluidized beds were similar. Meanw hile,the pressure drop in the wet particle vibrating fluidized bed decreases firstly and then increases with the increase of the liquid content. In the wet particle vibrating fluidized bed,the minimum fluidization velocity decreases with the increase of the vibration intensity,increases firstly and then decreases w ith the increase of the liquid content,increases with the increase of the particle size. The calculation formula of the minimum fluidization velocity of Geldart-D wet particles in vibrating fluidized beds is obtained.