McCabe-Thiele Diagrams: ConcepTest and Example Problem

Try to answer this ConcepTest and solve the example problem before using this module. Studies show that trying to answer the questions before studying material improves learning and retention. We suggest that you write down the reasons for your answers. By the end of this module, you should be able to answer these on your own. Answers will be given at the end of this module.

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Example Problem 1

Acetone and ethanol are separated using a distillation column with a partial condenser and partial reboiler. An equimolar, sub-cooled liquid feed enters at 100 kmol/hr and condenses 1 mol of vapor for every 6 mol of feed. The separation requires a distillate vapor that is 95 mol% acetone and bottoms liquid that is 5 mol% acetone. The reflux is returned from the condenser to the column as a saturated liquid and the operation is run at (L/V) =1/4*(L/V)min. Assume constant molar overflow conditions. Perform the following:
   1. Plot the operating lines for the rectifying and stripping sections and the feed line. 
    2. Determine the number of equilibrium stages required and number of trays if each tray has an efficiency of 1. 
    3. Determine the optimal feed location.
    4. Determine the molar flow rates in and out of the condenser (V and D) and boiler (L and B).