强制浆液外循环三相气升式内环流反应器的气含率特性

Gas Holdup Characteristics in a Three-phase Inner Airlift Reactor with External Slurry Circulation

在有机玻璃制成的组合反应器(φ0.284×3.0m)内,采用空气、水和玻璃微珠(密度为2420kg/m3和平均粒径为5.92×10-4m)的气液固三相体系考察了不同表观气速下环流反应器内不同流动区域的径向局部气含率和内、外环轴向平均气含率分布特性.局部气含率采用电导探针法测定,轴向平均气含率由局部气含率的截面积分得出.结果表明气含率均随表观气速的增大而增大;外环循环流入内环的气泡量少;在相同条件下外环的气含率远远低于内环的气含率.浆液外循环的引入和新型气体分布器的采用可以增大导流筒内气体与浆液两相的接触面积和湍动强度,从而使传递过程得到了强化.

Radial and axial gas holdup characteristics in an inner airlift reactor with external slurry circulation are investigated under different superficial gas velocities.The experimental installation made of plexiglass with an inner diameter of 0.286 m and a height of 3.0 m includes a spray,perforated plates and an airlift reactor.Air,tap water and glass beads with a density of 2420 kg/m3 and an average diameter of 5.92×10-4 m are employed as the gas,liquid and solid of three phases,respectively.The local radial gas holdup is measured by the electrical conductivity probe technique,and the average axial gas holdup is calculated by using the area integral of the local radial gas holdup.It is found that the gas holdup increases with increasing the superficial gas velocity,and the gas holdup in external loop is much lower than that in the inner loop at the same superficial gas velocity.The bubbles enter the draft tube from the annular can be neglected in the ranges of our operating conditions.It should be noticed that the conventional airlift reactor with external slurry circulation and a new type of distributor enhances the interfacial area between gas and slurry phases and the turbulent intensity of multiphase flow,which will improve the interphase transfer in the gas distributor region and downcomer tube region.