D ln T eTf

For a binary mixture we usually omit the component index for the light component, i.e. we write x"x1 (light component) and x2 = 1 — x (heavy component). Then the VLE relationship becomes:

The following empirical formula is frequently used to compute the pure component vapour pressure:

The coeffidents are l1sted 1n component property databases. The case w1th d = e = 0 1s called the Anto1ne equat1on.

/C-values and Relative Volatility

The K-value for a component i 1s defined as: K1 = y/x. The K-value 1s somet1mes called the equ1-l1br1um constant, but th1s 1s m1slead1ng as 1t depends strongly on temperature and pressure (or compos1-t1on).

The relative volatility between components i and j 1s defined as:

This equilibrium curve is illustrated in Figure 2.

The difference y— x determines the amount of separation that can be achieved on a stage. Large relative volatilities imply large differences in boiling points and easy separation. Close boiling points imply relative volatility closer to unity, as shown below quantitatively.

Estimating the Relative Volatility from Boiling Point Data

The Clapeyron equation relates the vapour pressure temperature dependency to the specific heat of vaporization (AHvap) and volume change between liquid and vapour phase (AVvap):

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.

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