10.02 - Vapor-Liquid Equilibrium (VLE) Calculations

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Use VLookup and Eqn. 2.47 to tabulate shortcut estimates of Antoine coefficients. (6min, uakron.edu) By calculating these in a distinct location, then referencing those estimates in the cells that will actually be used for later calculations, you can type in precise estimates when you have them. When no precise values are available, recover the shortcut estimates by simply typing "=" and referencing the cell with the shortcut estimate. This screencast includes sample calculations of the shortcut Antoine coefficients of methanol and benzene.

Comprehension Questions:

1. Estimate the Antoine "A" coefficient for methanol according to the shortcut method.
2. Estimate the Antoine "B" coefficient for benzene according to the shortcut method.
3. Estimate the Antoine "C" coefficient for ethanol according to the shortcut method. Compare to the "C" coefficient reported in Apx. E.
4. Estimate the Antoine "A" coefficient for ethanol according to the shortcut method. Compare to the "A" coefficient reported in Apx. E.
5. Estimate the Antoine "B" coefficient for water according to the shortcut method. Compare to the "A" coefficient reported in Apx. E.

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Use VLookup and shortcut estimates of Antoine coefficients (see above) to quickly generate the Pxy phase diagram for an ideal solution. (11min, uakron.edu) This video shows a sample calculation for methanol+benzene using Eqn. 10.8. It also shows how to reference the approximate estimates in the cells that will actually be used for later calculations, so you can type in precise estimates when you have them. When no precise values are available, recover the shortcut estimates by simply typing "=" and referencing the cell with the shortcut estimate. The predictive formulas are written in black and should not be edited. The cells for user modification by pasting more accurate values are indicated in blue. We use this approach a lot, and refer to it fondly as the "black and blue" method.

Note: This is a companion file in a series. You may wish to choose your own order for viewing them. For example, you should implement the first three videos before implementing this one. Also, you might like to see how to quickly visualize the Txy analog of the Pxy phase diagram. If you see a phase diagram like the ones in section 11.8, you might want to learn about LLE phase diagrams. The links on the software tutorial present a summary of the techniques to be implemented throughout Unit3 in a quick access format that is more compact than what is presented elsewhere. Some students may find it helpful to refer to this compact list when they find themselves "not being able to find the forest because of all the trees."

Comprehension Questions:

1. Create a Pxy diagram for methanol+benzene at 90C based on the ideal solution SCVP model. Be sure to include all appropriate labels and label your sketch as quantitatively as possible. Compare your model to the data in HW 11.10 by including those points in the plot. Explain similarities and discrepancies.
2. Sketch a Pxy diagram for acetone+acetic acid at 55C based on the ideal solution SCVP model. Be sure to include all appropriate labels and label your sketch as quantitatively as possible. Compare your sketch to Figure 10.9a. Explain similarities and discrepancies.
3. Sketch a Pxy diagram for acetone+chloroform at 35.17C based on the ideal solution SCVP model. Be sure to include all appropriate labels and label your sketch as quantitatively as possible. Compare your sketch to Figure 10.9c. Explain similarities and discrepancies.
4. Sketch a Pxy diagram for 2-propanol+water at 30C based on the ideal solution SCVP model. Be sure to include all appropriate labels and label your sketch as quantitatively as possible. Compare your sketch to Figure 10.8c. Explain similarities and discrepancies.

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VLE Routines - General Strategies (4:49) (msu.edu)

Deciding which routine to use is more challenging than it appears. Also understanding the strategy used to solve the problems is extremely helpful in being able to develop the equations to solve instead of trying to memorize them.

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