Abstract：The hydrodynamic characteristics and particle mixing behavior in an disordered air-loop mixer with an internal diameter of Æ286 mm without draft tube were investigated. In the experiment, the catalytic fluid cracking (FCC) gas catalyst was employed as fluidized medium. Under the experimental conditions of the superficial gas velocity 0.3-0.5 m/s in the central area, 0.1 m/s in the annulus zone and particle feeding mass flow rate 0.25-1.00 kg/s (based on the cross-section area of the draft tube, the cross-sectional density of the bed in the mixer was measured using a PV-6D particle velocity-density analyzer and the Radial Non-uniformity Index (RNI) under different operating conditions was also given. The dimensionless temperature distribution of the cross section of the mixer was measured using the thermal particle tracer technology. The mixing index was introduced to quantitatively describe the degree of particle mixing under different operating conditions. At the same time, comparison between the conventional and the disordered loop mixers was made. The results showed that the density of the inner bed in the disordered circulation mixer was low in the center region and high in outer region. With the increase of the mass flow rate, the RNI decreased and then increased. With the increase of superficial gas velocity, the RNI increased. The mixing index of pre-mixing zone was 0.7-0.9. Under the experimental conditions of high mass flow rate and low superficial gas velocity, the cross section mixing index in downcomer outlet zone was lower than that under other experimental conditions. In addition, the mixing capacity of the disordered air-loop mixer was superior to that of the conventional circulation mixer.
Zhang Bofeng,Qin Di,Meng Zhenliang et al. Hydrodynamics and Particle Mixing Characteristics of a Disordered Air-Loop Mixer Without Draft Tube[J]. 化学反应工程与工艺, 2017, 33(2): 104-115.
