强制液体外循环气升式环流反应器中内环气含率分布  

Profiles of gas holdup in the inner loop of an airlift reactor with external liquid circulation

作　　者：金家琪[1] 王莉[1] 张锴[1] 卢春喜[1] 

机构地区：[1]中国石油大学(北京)重质油国家重点实验室,北京102249

出　　处：《燃料化学学报》2007年第6期748-753,共6页Journal of Fuel Chemistry and Technology

基　　金：国家重点基础研究发展规划(973计划;2005CB221205);国家自然科学基金(20676147);教育部留学归国人员科研启动基金(2004-527)。

摘　　要：在常规环流反应器基础上,将液体强制外循环并采用中心下料管和环管式气体分布器结构,该反应器主体(φ0.284m×3.0m)是有机玻璃制成的。采用空气-水气液两相体系以考察气体速度和外循环液体速度对内环气含率轴径向分布的影响。实验结果表明,内环局部气含率和轴向平均气含率均随表观气速和外循环液速的增大而增大;在不同的轴向位置,内环气含率的径向分布特性有所差异,其原因是由研究所采用的特殊反应器结构所致;内环轴向平均气含率先随轴向高度的升高而增大,在离开导流筒后略有降低。在此基础上采用商业软件ANSYSCFX10.0对该反应器进行数值模拟。模拟结果表明,装置的非轴对称导致内环气含率呈非轴对称分布特性;截面平均气含率在分布器上方出现骤然增大,由于下料管液流的影响在其下方出现一个相对低点,这对实验研究起到了补充作用。因此,对于新型反应器的研发,可采用实验与模拟相结合的策略。The radial and axial gas holdups in the inner loop of an airlift reactor with a down tube and an annulus gas distributor are investigated under different superficial gas and external liquid circulation velocities. Experimental installation is made of plexiglass with an inner diameter of 0.284 m and a height of 3.0 m. Air and tap water were used as the gas and liquid phase, respectively. The experimental results show that the radial gas holdup within the inner loop increases with an increase of superficial gas or external liquid circulation velocity. These distribution characteristics at different axial locations are influenced obviously by the reactor structure. The axial profile of the section-averaged gas holdup firstly increases with axial height increasing, and then decreases slightly above the exit of the draft tube. Furthermore, the distributions of gas holdup are numerically computed by using an ANSYS CFX10.0 software package. The computational results indicate that the radial distributions of gas hold-up are non-axial symmetry in nature, which is caused by the non-axial symmetry of the set-up. The axial gas holdup increases dramatically above the gas distributor. There exists a minimal gas holdup below the exit of the down tube, which is resulted from the external liquid. The simulated data aforesaid can provide additional information for the experimental investigation. Therefore, it is suggested that the method combining experiment with simulation is suitable for the development of a new type of multiphase reactor.

关 键 词：气升式环流反应器 液体外循环 内环 气含率 实验与数值模拟 

分 类 号：TQ021.1[化学工程]