Question

As head separations engineer at BASF, you are designing a distillation process to separate chlorobenzene and benzene. Your initial feed stream is a saturated liquid, has a flowrate of 500 kmol/hr and is 50 mol% benzene. The column available to you has a total condenser and a partial reboiler. The average relative volatility is 2.5. You need to achieve a distillate that is 4 mol% chlorobenzene and a bottoms that is 97 mol% chlorobenzene.

a) What are the distillate and bottoms flow rates?

b) What is the minimum reflux ratio? How many stages would you need if you operated at the minimum reflux ratio?

c) If your reflux ratio is infinite, what is your boil-up ratio? How many stages would you need if you operated at infinite reflux?

Hint: Apply your knowledge of multi-component distillations.

The initial information you received from the reaction design team was incorrect. Your feed stream is actually arriving as a saturated vapor.

d) Now that your feed stream is a saturated vapor, do your distillate and bottoms flow rates change? If so, what are they now?

e) If your feed stream is a saturated vapor, what is the minimum reflux ratio? How many stages would you need if you operated at the minimum reflux ratio?

f) If your feed stream is a saturated vapor and your reflux ratio is infinite, what is your boilup ratio? How many stages would you need if you operated at infinite reflux?

Hint: Apply your understanding of distillations at total reflux.

Answer 1

Please feel free for any queries in the comment. Please comment if you have any doubt related to the solution. Please upvote if you like the solution

Thank you students