You're kidding me.

Since this weekend I have plodded systematically through the first two problems of my Separations homework. I get to the third problem and parts a and b I plod through too.

Then I get to part c.

For part c, one of 5 parts to one of 3 homework problems I have to:

Find the minimum reflux ratio. To do that, I have to solve the Underwood equation. Okay, fine, there should be a way I can do that in Excel.

The Underwood equation requires the fractions of the five components in the distillate. Okay, I found that in part b. It also requires the relative volatility at the feed conditions.

Wait. What are the feed conditions?

The feed conditions are 120 kPa. That's all well and good, but I have to know the temperature to find the relative volatility. What's the temperature.

Oh, the feed is at it's bubble point. That helps.

Wait a second. No it doesn't.

To find the bubble point I have to:

-estimate the temperature
-find the K value for each of the five components off a chart in Chapter 2
-find a correlation between the vapor pressure of each species from the online copy of Perry's Handbook for Chemical Engineers
-Use Excel to solve all those vapor pressure correlations for the temperature
-repeat
-repeat
-repeat
-repeat

Keep in mind that after I do that, I have to:

-find the relative volatility for each component from those K's I was iterating with
-solve one equation to get those roots
-plug those roots into another equation to get the actual relux ratio

This is why I hate Separations.

With the fire of a thousand suns.