Ternary Interactive Application
Ternary Interactive Application
This is an interactive system allowing you to learn how to use ternary diagrams and to design liquid-liquid extraction (LLE) systems using graphical methods.
There are 3 key activities available to help you fully understand these graphical methods:
The information below will help you understand these activities before you practice them on the links above.
In liquid-liquid extraction, a liquid feed of two (or more components) is contacted with a second liquid phase, called the solvent, which is immiscible (or only partly miscible) with one or more feed components and completely (or largely miscible) with one or more of the other feed components. Thus, the solvent, partially dissolves certain species of the liquid feed, affecting at least a partial separation of the feed components.
Extraction has been practiced since the time of the Romans, who used molten lead to separate gold and silver from molten copper by extraction. However, it was not until the early 1930s that Lazar Edelaunu invented the first large-scale extraction process. The Edeleanu process is used in the petroleum refining industry, whereby liquid sulfur dioxide is used to extract aromatics from liquid kerosene at around -20°C.
Liquid-liquid extraction has grown in importance since then because of the demand for temperature-sensitive products, higher-purity requirements, better equipment, and availability of solvents with higher selectivity, and is also an important method in bio-separations.
The video below explains the basic concepts of liquid-liquid extraction, how to represent ternary systems on diagrams, and then how to use these to calculate equilibrium separations.
For a single stage system, the extract and raffinate compositions are limited by the liquid-liquid equilibrium tie lines. Often these compositions are not suitable for the separation that is needed. To improve the separation a multi-stage method can be used. Stagewise extraction calculations for Type I and Type II systems are most conveniently carried out with ternary equilibrium diagrams.
The video below explains how to use the Hunter-Nash method to calculate the number of stages needed for a multi-stage separation. It also discusses general design considerations for LLE systems.
For more information on other chemical engineering separation techniques please visit:
Advanced Engineering Separations Channel on YouTubeFor other general Chemical Engineering resources please visit:
Chemical Engineering Teaching Resources