FL fV i 1 to m

A relative volatility close to unity means that the separation of the two components is likely to be difficult, whereas a relative volatility much greater or much less than unity means that few equilibrium stages are likely to be needed for separation. For binary system, eqn [2] can be rearranged to give:

where m is the total number of components in the system, and L and V represent the liquid phase and the vapour phase, respectively. In order to use this relationship, the fugacities must first be related to the compositions in the two phases in equilibrium. This is done using the following thermodynamic relationship in terms of the variables T, P and n:

Eqn [3] is plotted in Figure 1 for various (constant) values of the relative volatility. Note that an increase in the relative volatility leads to an increase in the concentration of the more volatile component in the vapour phase. When the relative volatility has a value of 1, yi = xi and separation is no longer feasible. A relative volatility of 1 also signifies the existence of an azeotrope or a critical point. A framework for the correlation and prediction of K values (and hence or the equivalent relationship in terms of T, V and ni:

Solar Panel Basics

Solar Panel Basics

Global warming is a huge problem which will significantly affect every country in the world. Many people all over the world are trying to do whatever they can to help combat the effects of global warming. One of the ways that people can fight global warming is to reduce their dependence on non-renewable energy sources like oil and petroleum based products.

Get My Free Ebook

Post a comment