两段气固环流反应器流体动力学行为和传质特性的研究

Hydrodynamics and Mass Transfer Characteristics of a Novel Two-stage Gas-Solid Internal Airlift Loop Reactor

借鉴气液环流的理论,提出了气固多段环流的设想.以空气和FCC催化剂为介质,在内环表观气速为0.089～0.424m/s、外环表观气速为0.04～0.08m/s的范围内,在一套两段气固环流反应器内系统研究了两段环流反应器内颗粒的流体动力学行为和气固传质特性.发现反应器平均颗粒密度随着内环表观气速的增加而减小,随外环表观气速的增加变化不大.一段、二段环流速度随着内环表观气速的增加而增加,随外环表观气速的增加略有减小.环流反应器汽提效率随内环表观气速的增加而增加,随外环表观气速的增加略有减小,两段环流反应器的汽提效率大于单段环流反应器.

Based on the theory of gas-liquid airlift loop reactor,a novel two-stage gas-solid internal airlift loop reactor(GSIALR) was explored.Experiments were conducted to investigate the local hydrodynamics and mass transfer characteristics in the GSIALR.Air and FCC catalyst were employed as the gas and solid.The superficial gas velocity in the draft tube and the annulus vary from 0.089 to 0.424 m/s and 0.043 to 0.087 m/s,respectively.Local catalyst density and circulation velocity of the first and the second stage were extensively discussed.The mean catalyst density of GSIALR was found to decrease with the increase of the superficial gas velocity in the draft tube,but increase slightly with the increase of the superficial gas velocity in the annulus.As the superficial gas velocity in the draft tube increases,the catalyst circulation velocity of the first and the second stage increase.However,when the superficial gas velocity in the annulus increases,the catalyst circulation velocities decrease slightly.Moreover,the stripping efficiency of the GSIALR was measured,which increases with increasing the superficial gas velocity in the draft tube,but decreases slightly with increasing of the superficial gas velocity in the annulus.It was also found that the stripping efficiency of the two-stage GSIALR was higher than that of the single stage GSIALR.