【摘要】 在一个具有四流道的多室气升式环流反应器中,对空气-水体系,用电导脉冲示踪技术以饱和氯化钾溶液为示踪剂,对器内轴向分散及混合特性进行实验研究。用波登斯坦准数(BO)表征轴向分散特性,混合时间(tm)表征混合特性。实验中,固定一个上升区(3区)的表观气速(0.0037～0.0246m·s-1),改变另一个上升区(1区)的表观气速(0.0081～0.0313m·s-1)。结果表明,两个上升区的表观气速共同影响循环液速,进而影响器内的轴向分散及混合特性。固定3区表观气速,波登斯坦准数(BO)和混合时间(tm)均随1区表观气速的增大而减小,并随固定气速的增大而减小。BO值在60～130之间变化,说明器内返混程度相当小。tm值在80～110s之间变化,即需6～8次循环器内物料可充分混合。由此可见,该多室气升式环流反应器内的液体流动接近于平推流。更多还原

【Abstract】 The axial dispersion and mixing behavior in a multi-compartment airlift loop reactor with four channels were experimentally investigated with electric conductance-impulse tracer technology for air-water system. The tracer is saturated KCl solution. Bodenstein number (B_O) and mixing time (t_m) represent axial dispersion behavior and mixing behavior, respectively. The range of the fixed superficial gas velocity in one riser (0.003　7～0.024　6　m/s) changed the one in the other (0.008　1～0.031　3　m/s). The results show that the superficial gas velocities of both two risers have affected on liquid circulation rates, then, on the axial dispersion behavior and mixing behavior in the reactor. As the superficial gas velocity in one riser is fixed, B_O and t_m decrease with the increasing of another’s, and decrease with the increasing of the fixed gas velocity. When the values of B_O are variable in 60～130, the back-mixing degree is quite small in this reactor. When the change range of t_m is 80～110　s, it indicates material flow in this ALR can be fully mixed after circulation of 6～8 times. Therefore, liquid flow in this multi-compartment airlift loop reactor approaches to plug flow.更多还原