Liquid-liquid extraction - 2012

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Class date(s): 23 to 26 October 2012
Download video: Link [102 M]

Download video: Link [123 M]

Download video: Link [127 M]

Download video: Link [119 M]

Download video: Link [119 M]

We start this section by looking at liquid-liquid extraction.

References

Please use these references to read ahead, or for extra background reading on liquid-liquid extraction. In alphabetical order:

  • Ghosh, R. "Principles of Bioseparations Engineering", Chapter 7, McMaster (reserve)
  • Geankoplis, C.J. "Transport Processes and Separation Process Principles", Chapter 12 in 3rd and 4th edition, McMaster Libraries (reserve)
  • Perry's Chemical Engineers' Handbook, Chapter 15, Direct link (McMaster subscription)
  • Richardson and Harker, "Chemical Engineering, Volume 2", 5th edition, Chapter 13 ebook
  • Schweitzer, "Handbook of Separation Techniques for Chemical Engineers", Chapter 1.9, McMaster library
  • Seader, Henley and Roper, "Separation Process Principles", Chapter 8 in 2nd and 3rd edition McMaster Libraries (reserve)

Interesting applications / Enrichment materials

  • An article on liquid-liquid extraction which describes the various units available.
  • The flowsheet for separating acetic acid from water using ethyl acetate solvent. This flowsheet has the mass flow rates, to help contrast it to distillation.
Acetic-acid-water-ethyl-acetate-flowsheet-Seader-3ed-p300.jpg
click to enlarge

Week 8

23 Oct 2012 (08A)

25 Oct 2012 (08B)

26 Oct 2012 (08C)

Board-26-Oct-2012-A.jpg click to enlarge
Board-26-Oct-2012-B.jpg click to enlarge
Board-26-Oct-2012-C.jpg click to enlarge

Week 9

30 Oct 2012 (09A)

We will consider single and multiple co-current extraction.

Board-30-Oct-2012.jpg click to enlarge

31 Oct 2012 (09B)

We should be able to wrap up the section by studying counter-current liquid-liquid extraction.

  • Slides for class Please print slides 48 to 54 on large, single pages, to assist your learning.
  • Audio and video recording of the class.
  • Photo of the board during class
Board-01-Nove-2012.jpg click to enlarge

01 Nov 2012 (09C)

  • Slides for class (slide 58)
  • There will be no formal teaching in class today. You can ask questions about assignment 4, and there will be a tutorial question from assignment 5.
Consider a system for which you have been given the ternary diagram (see slide 59 and 60). \(A\) = solute, \(S\) = solvent, \(C\) = carrier. The feed, \(F\) enters at 112 kg/hr with composition of 25 wt% solute and 75 wt% carrier.
  1. Calculate the flow and composition of the extract and raffinate from:
    • 1st co-current stage, using a pure solvent flow of 50 kg/hr.
    • 2nd co-current stage, with an additional solvent flow of 50 kg/hr.
  2. For the overall 2-stage system, find the:
    • overall recovery
    • overall concentration of combined extract streams
The next objective is to have a counter-current system so the raffinate leaving in the \(N^\text{th}\) stage, \(R_N\) has \(y_{R_N} = 0.025\)
  1. What is the maximum allowable solvent flow?
  2. Explain whether it's possible to achieve an extract stream of \(y_{E_1} = 0.21\)?
  3. Show the construction on the ternary diagram for the number of equilibrium stages to achieve \(y_{R_N} = 0.025\), given a solvent flow of 60 kg/hr.
  4. Plot on the same axes the concentrations in the extract and raffinate streams.