Results-Equilibrium Curve
Generate the xy equilibrium diagram to study the mixture behavior of ethanol–water. You can observe a positive azeotrope at higher composition of ethanol in the mixture.
1
In the Model Builder window, right-click the Results  node and select 1D Plot Group 1 .
2
In the Settings window for 1D Plot Group, type Equilibrium Curve in the Label text field.
3
Locate the Plot Settings section and select the x-axis label checkbox. In the associated text field, type Liquid ethanol mole fraction (x1).
4
Select the y-axis label checkbox. In the associated text field, type Vapor ethanol mole fraction(y1).
5
Click to expand the Title section. From the Title type list, choose None.
6
Locate the Legend section. From the Position list, choose Middle right.
Global 1
1
In the Equilibrium Curve toolbar, click Global .
2
In the Settings window for Global, locate the y-Axis Data section.
3
Plot the equilibrium curve as mole fraction of ethanol in vapor phase versus mole fraction of ethanol in liquid phase.
4
In the table, type x_y(P,n,x1,x2). Alternatively click Replace Expression  and find the function under
Global Definitions > Functions
5
Click to expand the Legends section. Clear the Show legends checkbox.
6
Click to expand the Coloring and style section. In the Width text field, type 2.
7
On the Equilibrium Curve toolbar, click Plot .
Now, use the Reaction Engineering (re)  interface as a means to define the chemical system and to couple to the thermodynamic system. To simplify, name the ethanol species E and the water species W.