1. Unit Operations Laboratory Distillation Analysis Seminar Super Team 2005
Monday, December 5, 2005
2:30 PM

2. Presentation Overview
Introduction
Distillation Safety
Operating Procedure
Composition Flow Chart
Experimental vs. Predicted Results
Sensitivity of CHEMCAD
Conclusions

3. Sensitivity Study Using CHEMCAD SCDS Column How to separate Ethanol from Propanol ?

4. Overview Fixed Parameters for the Study Purpose
CHEMCAD SCDS Process Flow Diagram
Variables
Results for Feed Tray at 1
Results for Feed Tray at N/2
Results for Feed Tray at N

5. Fixed Parameters for the Study
Specifications:
Adiabatic distillation column
Ideal equilibrium trays
Feed flow rate = 3.5 mol/min
Feed composition, xF = 0.50 mole fraction ethanol
Feed temperature = 50 ºC
Feed pressure = 1 atm
Reflux temperature = 50 ºC
Reboiler duty = 1300 W
(Note the number of stages used in CHEMCAD is actually N+2 to account for the condenser and reboiler, where N is the number of trays.)

6. Purpose
To conduct an in depth study on the effects of the following variables on the mole fractions of ethanol in the distillate and bottoms flow streams:
Reflux Ratio
Number of Trays

7. CHEMCAD SCDS Process Flow Diagram Fixed Parameters for the Study
Reflux Properties
Temperature = 50 ºC
Feed Stream
Flow Rate = 3.5 mol/min
Ethanol Composition = 0.5 mole fraction ethanol
Temperature = 50 ºC
Pressure = 1 atm
Reboiler Properties
Reboiler Duty = 1300 W

8. Variables The effect of independent variables: Reflux ratio
Number of trays
1, 2, 4, 8, and 16
Feed tray location
Top = 1 , Middle = N/2, Bottom = N
On the dependent variables:
xD, the mole fraction of EtOH in the distillate, and xW, the mole fraction of EtOH in the bottoms.

9. Results for Feed Tray at 1
Reflux
N = 1
N = 2
N = 4
N = 8
N = 16
Ratio xD xW
0.5
0.686
0.433
0.706
0.426
0.716
0.422
0.717
0.421 1
0.699
0.452
0.448
0.725
0.446
0.726
0.445
1.5
0.705
0.463
0.723
0.460
0.730
0.458
0.731 2
0.710
0.470
0.467
0.733
0.466
0.734
2.5
0.713
0.474
0.729
0.472
0.736
0.471 3
0.715
0.478
0.476
0.737
0.475
0.738
3.5
0.480
0.732
0.479
0.739 4
0.718
0.483
0.481
0.740
4.5
0.719
0.484
0.741 5
0.486
0.735
0.485
5.5
0.720
0.487
0.742 6
0.721
0.488
0.743
6.5
0.489 7
0.722
7.5
0.490
0.744 8
0.491
8.5 9
0.492

10. Distillate for Feed at N = 1

11. Bottoms for Feed at N = 1

12. Results for Feed Tray at N/2
Reflux
N = 1
N = 2
N = 4
N = 8
N = 16
Ratio xD xW
0.5
0.686
0.433
0.706
0.426
0.758
0.406
0.788
0.395
0.794
0.392
1.0
0.699
0.452
0.717
0.448
0.789
0.430
0.849
0.414
0.882
1.5
0.705
0.463
0.723
0.460
0.805
0.444
0.883
0.429
0.940
0.418
2.0
0.710
0.470
0.726
0.467
0.816
0.454
0.903
0.440
0.967
2.5
0.713
0.474
0.729
0.472
0.823
0.461
0.915
0.449
0.979
3.0
0.715
0.478
0.731
0.476
0.828
0.466
0.923
0.455
0.984
3.5
0.716
0.480
0.732
0.479
0.831
0.929
0.988
4.0
0.718
0.483
0.733
0.481
0.834
0.473
0.933
0.464
0.990
0.459
4.5
0.719
0.484
0.734
0.837
0.475
0.937
0.991
5.0
0.486
0.735
0.485
0.838
0.477
0.939
0.992
5.5
0.720
0.487
0.736
0.840
0.942
0.993
0.469
6.0
0.721
0.488
0.841
0.943
6.5
0.489
0.737
0.843
0.482
0.945
0.994
7.0
0.722
0.844
0.946
7.5
0.490
0.845
0.947
8.0
0.491
0.738
0.948
0.995
8.5
0.846
0.949
9.0
0.492
0.847

13. Distillate for Feed at N/2

14. Bottoms for Feed at N/2

15. Results for Feed Tray at N
Reflux
N = 1
N = 2
N = 4
N = 8
N = 16
Ratio xD xW
0.5
0.686
0.433
0.732
0.416
0.758
0.406
0.763
0.404
0.764
1.0
0.699
0.452
0.767
0.435
0.826
0.420
0.858
0.412
0.864
0.410
1.5
0.705
0.463
0.786
0.448
0.866
0.926
0.421
0.957
0.415
2.0
0.710
0.470
0.797
0.457
0.889
0.442
0.960
0.431
0.995
0.426
2.5
0.713
0.474
0.805
0.904
0.450
0.974
0.441
0.999
0.438
3.0
0.715
0.478
0.811
0.467
0.913
0.456
0.982
0.446
3.5
0.716
0.480
0.816
0.471
0.920
0.461
0.986
0.454
1.000
0.453
4.0
0.718
0.483
0.819
0.925
0.465
0.988
0.459
0.458
4.5
0.719
0.484
0.822
0.476
0.929
0.468
0.990
0.462
5.0
0.486
0.824
0.932
0.991
0.466
5.5
0.720
0.487
0.935
0.473
0.992
0.469
6.0
0.721
0.488
0.827
0.482
0.937
0.475
0.472
6.5
0.489
0.829
0.938
0.477
0.993
7.0
0.722
0.830
0.940
7.5
0.490
0.831
0.485
0.941
0.479
0.994
8.0
0.491
0.832
0.942
0.481
8.5
0.723
0.943
9.0
0.492
0.833
0.944

16. Distillate for Feed at N

17. Bottoms For Feed at N