Developmental Study on a Liquid - Liquid Extractor with Supported Interface in a Porous Material

点击翻译按钮获取中文摘要

A liquid-liquid extraction equipment proposed here is a new type of mass transfer equipment keeping a liquid-liquid interface in a porous material through which each of the liquid can pass easily.In this reseach, using porous pipes made of wire netting the following two kinds of experiment were performed to examine the characteristics of this type of equipment. One is a fluid flow experiment for water-kerosene system to investigate on stability of the liquid-liquid interface supported in the porous pipe and the other is an extraction experiment using acetic acid as a solute.1. Fluid flow experiment The operating range keeping a stable interface was investigated for a few pipes made of wire netting of different mesh number. In the experiment, water flows downward in this pipe and kerosene flows upward in the outside annulus. The operating range was subjected to the difference between the static pressures of each phase and became wider with increase of mesh number of the wire netting. Th … More is result duggests that capillary pressure due to interfacial tension plays an important role. But the quantitative explanation can not yet been succeeded.2. Extraction experiment By adding acetic acid to water-kerosene system the interfacial tension decreased sharply and the operating range was found to become narrow. So the extraction experiment was conducted using only a wire netting pipe of mesh number-400, the finest one among the pipes used above. The experimental results were evaluated by the product of the overall mass transfer coefficient K_w and the interfacial area A. The K_wA value could be predicted to be between the estimated ones under assumption that the interface is at the outer face (hydrophilic) and the inner face (hydrophobic) of the porous pipe. From the estimated vakue of K_wA it was found that the mass transfer resistance in the porous wall is controlling and is less affected by the flow rate of water- and kerosene-phases. However, the experimental results of K_wA showed a few times the estimated ones, and increased slightly with increase of the water flow rate. On these results we consider that the bulk flow of water- or kerosene -phase may influence fluid movement within the porous wall and this promotes the mass transfer rate. Therefore we are planning to clarify the influence of the porous material used, its pore size and the wall thickness on the mass transfer rate. Less