刮膜式微通道破乳塔液-液聚并机理研究

The production technology of industrial grade sodium dihydrogen phosphate from purifying wet-process phosphoric acid by emulsification extraction process has been developed by the applicant. In order to de-emulsify the emulsion rapidly and timely, the applicants attempt to design a new kind of microchannel liquid-liquid two-phase separation technology " scraped film microchannel de-mulsification tower ". The key problem of the subject is how to correctly describe the coalescence mechanism of the discrete droplets in the scraped film microchannel de-mulsification tower. The coalescence mechanism should be coupled including the keey vortex and fluctuating pressure from ripple factor which results in uneven discrete droplet force. So it is interesting to study the different coalescence mechanism under different conditions. At the same time, the Monte Carlo method is introduced to develop the quantitative research of the de-mulsification effect. A mathematical model is established for the coalescence process of the discrete droplets, in which the behavior of fluid flow, keey vortex and residence time, ripple factor, the collision force and motion of the discrete droplets, the deformation, collision and the contact time of the discrete droplets etc are all considered. It can be used to check, analysis and predict the droplet coalescence process in the scraped film microchannel de-mulsification tower. The design rule of the scraped film microchannel de-mulsification tower for the de-mulsification is also obtained. This study will further improve the development of the wet phosphoric acid purification technology. And it also can promote the theoretical study of the liquid-liquid two-phase separation technology.

申请者利用乳化萃取法开发了一种净化湿法磷酸生产工业级磷酸二氢钠技术。为了实现乳状液的快速、及时破乳，申请者创新性地设计和提出一种新型的 “刮膜式微通道破乳塔”来对乳状液进行破乳。如何阐明离散液滴聚并破乳的机理是本项目的关键，微通道破乳塔内离散液滴破乳聚并的机理应当是耦合，既有Keey涡的贡献，也有脉动因子引起的脉动压力导致离散液滴受力不均匀原因，需要研究不同聚并机理在不同条件下的贡献。申请者将Monte Carlo方法引入到离散液滴的聚并过程，开展聚并破乳效应的定量研究，模拟刮膜式微通道破乳塔内流体的流动状况、Keey涡的大小和停留时间、脉动因子、离散液滴受力和运动、离散液滴的形变、碰撞和接触时间等，建立一个能正确反映离散液滴聚并过程数学模型，对刮膜式微通道破乳塔内离散液滴聚并进行校验、分析和预测。项目研究将进一步完善和发展湿法磷酸净化技术，还促进微通道液-液两相分离技术的理论研究。

1当下社会油类制品产生的含油污水（有机废水）对人民的身体健康和环境污染产生巨大影响。因此，本项目为了进一步强化破乳及油水分离过程开发了刮膜式微通道破乳系统对乳液进行破乳研究。.刮膜式微通道破乳系统通过内转筒和外筒之间的间隙形成微通道，由旋转的内筒产生的离心力用以提高乳状液液滴在微通道壁上的随机碰撞概率，弥补了微通道破乳研究领域的不足。试验系统首先在不同的制备乳状液条件下，通过对剪切混合速率、剪切混合时间、相比和乳化剂加入量对于粒径大小、粒径分布以及重力沉降前后状态对比的影响进行研究。考察了进料体积流量、内筒旋转速度、倾斜角度和循环破乳次数对于水包油乳状液的破乳效果、破乳回收出的清澈有机相从上出口的分离能力和未破乳剩余乳状液粒径的影响。结果表明刮膜式微通道表现出优异的破乳性能，破乳的机制主要是离心力会增加液滴在微通道壁上的随机碰撞概率，从而造成的乳状液失稳。5次循环破乳后，乳状液和煤油-水乳状液的总破乳（有机相回收）效率均超过92％，获得的更高的破乳效果的同时至少比传统离心机破乳所使用的转速（R：4000 rpm）少一个数量级。.研究表明刮膜式微通道破乳系统内部的流型分为连续状流型(有机相乳相相间流和乳相流)，液滴状流型(有机相液滴乳相连续状流和有机相长液滴乳相连续状流)，平形状流型(机相环状乳相带状流和有机相带状乳相带状流)3类，6种。将乳状液进料流量和内筒旋转速度为坐标，绘制了不同设备结构和操作参数下的流型图。结果表明当刮膜式微通道破乳系统内部的液-液两相处于平形状流型时的破乳效果最好。最后，本项目绘制出的总破乳率关联图和普适流型图可以有助于对于刮膜式微通道破乳系统的精准控制。本项目对于新型微组件的开发、探索及应用有深远的意义。