# What Is a Txy Diagram?

August 2, 2022

## What are TXY diagrams?

Txy diagrams

It represents a binary mixture and all compositions are expressed as mole fractions of the more volatile component; x in the liquid phase or y in the vapor phase.

## How are TXY and XY diagrams useful?

The vapor-liquid equilibrium (VLE) x-y plot (vapour mole fraction versus liquid mole fraction) is shown for a methanol/water mixture fed to a flash drum. The corresponding T-x-y chart shows how the points are obtained in the x-y chart; each dot corresponds to a different temperature.

## What is a VLE diagram?

Vapor-Liquid Equilibrium (VLE) curves. Constant pressure VLE data are obtained from boiling point plots. Binary mixture VLE data is often plotted as shown in the figure to the right. The VLE diagram expresses the boiling point and dew point of a binary mixture at constant pressure.

## What relative volatility tells us?

Relative volatility is a measure that compares the vapor pressures of the components in a liquid chemical mixture. This quantity is often used when designing large industrial distillation processes.

## Is bubble point the same as boiling point?

For a single component, the boiling point and dew point are the same and are referred to as the boiling point.

## What is bubble point curve?

Bubble point curve – the curve separating the pure liquid phase (oil) from the two-phase region (natural gas and oil). This means that at a certain temperature, when the pressure decreases and below the boiling point curve, gas is emitted from the liquid phase into the two-phase region.

## How do you read a VLE curve?

The lower curve is the “saturated liquid” line, which gives the mole fraction of benzene in the liquid phase x. The upper curve is the “saturated vapor” line giving the mole fraction of benzene in the vapor phase y.

### References:

1. http://facstaff.cbu.edu/rprice/lectures/txydiag.html
4. https://learncheme.com/simulations/separations/txy-and-xy-diagrams-for-binary-vle-flash-drum/
5. https://www.rccostello.com/distil/distilvle.htm