Experimental study on gas-liquid-liquid macro-mixing in a stirred tank
Experimental study on gas-liquid-liquid macro-mixing in a stirred tank
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搅拌槽内气-液-液宏观混合实验研究
DOI：
10.1016/j.ces.2012.03.035
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发表时间：
2012-06-18
影响因子：
4.7
通讯作者：
Mao, Zai-Sha
中科院分区：
文献类型：
--
作者：
Cheng, Dang;Cheng, Jingcai;Mao, Zai-Sha
本文给出了在机械搅拌折流板槽内气-液-液分散体系中连续相混合时间和动力消耗的实验数据。采用电导率法测量混合时间，采用轴转矩法测量功率消耗。自来水作为连续相，煤油和空气作为分散相。考察了探针/示踪剂注入位置、搅拌速度、桨型、桨距罐底间隙、油体积分数、气含率以及分散液物性等因素对气-液-液体系宏观混合的影响。搅拌槽内气-液-液宏观混合现象与液-液、气-液搅拌槽的宏观混合现象有很大的相似性。实验结果表明，气-液-液宏观混合在较高气含率时得到增强，而在较低气含率时得到抑制。与气体效应相反，在低含率下分散油相增加了连续相的宏观混合强度，而在高含率下降低了连续相的宏观混合强度。实验结果表明，轴向搅拌桨比径向搅拌桨具有更高的能量效率。建立了一个简单的关联式，用于预测气-液-液三相体系的混合时间，并与实验数据进行了比较。(C)2012爱思唯尔有限公司保留所有权利。
In this paper, experimental data on the mixing time of the continuous phase and power consumption of gas-liquid-liquid dispersions in a mechanically agitated baffled tank are presented. The electrical conductivity method is taken for the measurement of mixing time and the shaft-torque method for power consumption measurement. Tap water is used as the continuous phase, and kerosene and air as the dispersed ones. The effects of probe/tracer injection position, agitation speed, type of impeller, clearance of impeller off tank bottom, oil volume fraction, gas holdup and physical properties of the dispersed liquids on the macro-mixing of the gas-liquid-liquid system have been investigated. The phenomenon of gas-liquid-liquid macro-mixing in a stirred tank is largely similar to that of liquid-liquid and gas-liquid stirred tanks. Our experiments indicate that the gas-liquid-liquid macro-mixing can be enhanced at higher gas holdups while damped at low gas holdups. Contrary to gas effect, the dispersed oil phase at low holdups increases the macro-mixing intensity but at higher holdups decreases the macro-mixing intensity of the continuous phase. The experimental results show that axial impellers are more energy efficient for gas-liquid-liquid macro-mixing than radial impellers. A simple correlation is developed for predicting the mixing time in gas-liquid-liquid three-phase systems and satisfactory agreement with experimental data is observed. (C) 2012 Elsevier Ltd. All rights reserved.