1. “Chemical Engineering Equilibrium Separations” Lectures 15 1 22-31 Oct 2012

2. In-Class Problem 2 benzene (17 mol%) toluene (66 mol%) m-xylene (17 mol%) F = 100 kmol/s sat’d liquid 1 atm DSTWU 1.0135 barPi star [bar] ComponentTbp oC80.1 oC123 oC Benzene80.11.01353.217 Toluene110.70.3871.42 m-Xylene139.10.1510.645

3. In-Class Problem 3

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9. Overview 9 AspenPlus: o Shortcut methods: DSTWU o Rigorous method: RADFRAC Efficiencies Introduction to multicomponent distillation (Chapter 9)

10. Homework Problem 10 benzene (17 mol%) toluene (66 mol%) m-xylene (17 mol%) F = 100 kmol/s sat’d liquid 1 atm X bz = 99 mol% X bz = 0.1 mol% DSTWU 1.0135 barPi star [bar] ComponentTbp oC80.1 oC123 oC Benzene80.11.01353.217 Toluene110.70.3871.42 m-Xylene139.10.1510.645

11. HWK Problem-molefrac specified 11

12. HWK Problem-molefrac specified 12

13. Overview 13 Review rigorous methods / RADFRAC Multicomponent systems: o Residue curves o DSTWU / RADFRAC o Rules of thumb Complex (Enhanced) distillation Column internals Batch distillation

14. 14 Multicomponent Rigorous Methods Rigorous Methods: solution of stage by stage material balances, energy balances, and thermodynamic equilibrium equations.

15. AspenPlus: RADFRAC 15 Rigorous two- or three-phase fractionation for single columns. Models absorbers, strippers, reactive distillation, and so forth. RadFrac is a rigorous model for simulating all types of multistage vapor liquid fractionation operations. In addition to ordinary distillation, it can simulate: o absorption, reboiled absorption, stripping, reboiled stripping, extractive and azeotropic distillation

16. Rigorous Model 16

17. AspenPlus: RADFRAC 17 Rigorous two- or three-phase fractionation for single columns. Models absorbers, strippers, reactive distillation, and so forth. RadFrac is a rigorous model for simulating all types of multistage vapor liquid fractionation operations. In addition to ordinary distillation, it can simulate: o absorption, reboiled absorption, stripping, reboiled stripping, extractive and azeotropic distillation RadFrac is suitable for: o three phase systems, narrow boiling and wide boiling systems, systems exhibiting strong liquid phase nonideality RadFrac can detect and handle a free water phase or other second liquid phase anywhere in the column. You can decant free water from the condenser. RadFrac can handle solids on every stage. RadFrac can model columns where chemical reactions are occurring. Reactions can have fixed conversions, or they can be: o equilibrium, rate controlled, electrolytic RadFrac can model columns where two liquid phases exist and different chemical reactions occur in the two liquid phases. RadFrac can also model salt precipitation. RadFrac can operate in rating mode or design mode. With Aspen Rate-Based Distillation feature, RadFrac can perform rate-based distillation calculations (packed tower configurations).

18. Rating Mode 18

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21. Design Mode 21

22. Rigorous Model 22

23. Multicomponent Methods 23 AspenPlus (methanol, ethanol, 1-propanol): Component P* i (64.5 oC) Keys MeOH1.013 bar EtOH0.5709 1-Propanol0.2534 AspenPlus Txy

24. “Residue” From Batch Distillation 24 Seader & Henley (2006)

25. Residue Curve Map 25

26. Residue Curve Map 26

27. Residue Curve Map 27

28. DSTWU 28 Z i = 1/3 R = 1.2 * R min MeOH recovery (dist.) = 99.9% EtOH recovery (dist.) = 0.1%

29. RADFRAC 29 Z i = 1/3 R = 5.2 N = 63 N F = 31 D = 33 kmol/h F = 100 kmol/h

30. Residue Curve Map 30

31. Plot Wizard 31

32. N F = 21 32

33. Set up Scheme 2 (1 st column only) 33 Run DSTWU Run RADFRAC Check performance

34. Questions? 34