3300 m^3大型气升式环流反应器数值研究

Numerical Study on 3 300 m^3 Large Air-Lift Loop Reactor

针对目前机械搅拌餐厨垃圾厌氧发酵罐存在搅拌能耗高、流场混合效果差等问题,课题组提出了气升式环流反应器。采用FLUENT软件对大型气升式环流反应器内气液两相流流场进行数值模拟,研究导流筒直径的变化对反应器内流场、气相体积分数和循环液速的影响。模拟结果表明:反应器内介质形成循环流动时,导流筒内侧沿壁处出现区域小面积环流。改变导流筒的直径及高度对反应器内气相体积分数影响较小,当导流筒直径为2. 5～2. 9 m或导流筒高度为15. 2～15. 8 m时,反应器内液体速率较大,环流效果较好。增大表观气速,反应器内气相体积分数和液体速率均有所增大。文中研究为大型环流反应器的结构优化提供参考。

Air-lift loop reactors were proposed for the current anaerobic fermentation tanks for mechanically stirred kitchen wastes have the problem of high mixing energy consumption and poor mixing effect in the flow field.The FLUENT software was used to simulate the gas-liquid two-phase flow field in a large air-lift loop reactor.The influence of the diameter of the guide tube on the flow field,gas holdup and circulating fluid velocity in the reactor were studied.The simulation results show that when the medium in the reactor forms a circulating flow,a small area circulation occurs along the inner side of the guide tube.Changing the diameter and height of the draft tube has little effect on the gas holdup in the reactor.When thediameter of theguidetubeisФ2.5~Ф2.9 mor theheight of theguidetubeis 15.2~15.8 m,the liquid velocity in the reactor is larger and the circulation effect is better.Increasing the apparent gas velocity,the gas content and the liquid velocity in the reactor are both increased.It provides a reference for structural optimization of large loop reactors.