Emulsion Liquid Membranes Process Design

The preparation and splitting of emulsions are the key parameters in an emulsion liquid membrane process. A very stable emulsion which avoids any loss of emulsified droplets is a prior condition for the feasibility of the process. However, the more stable the emulsion, the more difficult to split it. So both steps are dependent on each other and have to be optimized, also with regard to cost optimization. In the present work, we try to calculate the flow pattern in the two steps using CFD (computational fluid dynamics) software in order to improve the design of the two steps. 

In this paper an overview of the developments in liquid membrane extraction of cephalosporin antibiotics has been presented. The principle of reactive extraction via the so-called liquid-liquid ion exchange extraction mechanism can be exploited to develop liquid membrane processes for extraction of cephalosporin antibiotics. The mathematical models that have been used to simulate experimental data have been discussed. Emulsion liquid membrane and supported liquid membrane could provide high extraction flux for cephalosporins, but stability problems need to be fully resolved for process application. Non-dispersive extraction in hollow fib er membrane is likely to offer an attractive alternative in this respect. The applicability of the liquid membrane process has been discussed from process engineering and design considerations. 

In this chapter, we report the influence of surface-active compounds on the stability of crude oil emulsions using the apparatus designed for bilayer lipid membrane studies. The electrical method we employed to measure the film lifetime and thickness of model oils and crude oils seems to be a convenient technique for monitoring the coalescence processes in emulsions. The results obtained show that the natural surface-active substances in crude oil, such as petroleum acids and asphaltenes, have a great effect on the film strength. The ionized acids formed by the reaction between the petroleum acids and the alkali can decrease the interfacial tension and accelerate the thinning and breakdown of the thin liquid film. The asphaltenes can adsorb on to the interface and improve the stability of the film. The order of stability of the films between different oils and alkaline solutions is as follows crude oil with asphaltenes removed < crude oil < crude oil with both asphaltenes and petroleum-acids removed (iv) < crude oil with petroleum acids removed. In addition. 

---