A Quantitative Study of Drop Coalescence in Stirred Dispersion

本项目是研究搅拌液-液分散体中对液滴聚结的几种影响，这些影响可能被用来有效地控制液滴数量。因此，本文从实验和理论两个方面研究了表面电荷对液滴的影响以及不同方法对液滴合并现象的影响。表面电荷效应的控制是通过添加电解质和表面活性剂，以及改变介质的pH来完成的。研究了湍流强度对液滴聚结的影响，作为一种通过向弥散输入能量来控制液滴尺寸的方法。由于大多数工业液-液接触操作涉及高分散相分数，该项目通过利用自相似行为和缩放特性来研究稠密分散物。这项工作中提出的方法是独特的，因为信息将在单个液滴一级获得，从而获得作为液滴尺寸函数的合并速率，以及它们对其他物理参数的依赖。这项工作中建议研究的影响要么是完全未知的，要么充其量是模棱两可的，因为它是从对液滴尺寸分布不敏感的研究中获得的。重要的是要了解上述影响，以便控制分散相体系，以便能够在转化率和选择性方面以最佳方式执行接触操作。

This project is an investigation of several effects on drop coalescence in stirred liquid-liquid dispersions which may be used effectively to control drop populations. Thus the effect of surface charge on droplets and its manipulation by various means on coalescence phenomena is investigated experimentally and theoretically. The manipulation of surface charge effects are accomplished by addition of electrolytes and surfactants, and by varying the pH of the medium. The effect of turbulence intensity on drop coalescence is investigated as a method to control drop sizes by energy input to the dispersion. Since most industrial liquid-liquid contacting operations involve high dispersed phase fractions, the project investigates dense dispersions by exploiting self-similar behavior and scaling properties. The approach presented in this work is unique in that information will be obtained at the individual droplet level so that coalescence rates are obtained as functions of drop sizes in addition to their dependence on other physical parameters. The effects proposed for study in this work are either completely unknown or are at best ambiguous as obtained from studies insensitive to drop size distributions. It is important to understand the foregoing effects in order to control dispersed phase systems so that contacting operations can be performed optimally with respect to conversion and selectivity.