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Vapor Liquid Equilibrium

Every chemical engineer should know how to do vapor liquid equilibrium calculations, manually so you can write the next generation of computer programs!

We will show you how Aspenplus can be used to do Bubble Point Pressure, Bubble Point Temperature, Dew Point Temperature, Dew Point Pressure and Flash Calculations for a simple binary system consisting of 2-propanol (isopropyl alcohol) and water. Keep in mind that this system is highly non-ideal, that is Raoult's Law does not hold. In your textbook, the authors assume that this system can be adequately represented (in the liquid phase) by the Wilson Equation, the gas phase is assumed to be ideal, i.e. fugacity coefficient in the gas phase is equal to 1.0 for both components.

We will first show you how you can create a T-xy or a P-xy diagram.

First bring up Aspenplus ... use instructions elsewhere on these pages ... you will be creating a new run and doing what is called a Property Table Generation

Your screen should look like this

When you have entered all of the required information, you will see "Required Input Complete", for now you will see some Incomplete sign ...

Click the mouse on Forms and then Choose Setup Main

Remember the >> sign on the top right hand corner. Notice also the Next on the right top corner. They mean different things.

For now we will navigate using the >>

If you click on NEXT, Aspen will try to guess as to what you should do next, i.e. it has some built in intelligence.

next up previous
Next: Components Up: No Title Previous: No Title
Krishnan Chittur