1. Noor Ahmad · Thomas Deskins · Lily Li · Shiv Patel
Separations
Unit-Ops
Noor Ahmad · Thomas Deskins · Lily Li · Shiv Patel

2. Outline Types of Distillation Column Unit-Ops Industrial example
Shortcut Distillation
SCDS (Simultaneous Correction Distillation)
Tower Column
Tower Plus
Batch Distillation
Industrial example
Running a Column in ChemCad
Stream Reports & Plots

3. Shortcut Distillation
Used only for educational purposes
Not used by Industry
Not a rigorous column
Fenske-Underwood Method used
Rough Estimates for
Theoretical number of stages, Optimal feed location, Rmin, and fractional recoveries, etc.

4. SCDS Distillation Simultaneous Correction Distillation System
Non-ideal (activity coefficients, reactivity, etc)
Packed column
Models real behavior
Uses thermodynamics to calculate mass and energy balances

5. Tower Column Uses the inside-out rigorous method for multistage VLE
When computational power was limited, this was used more often than SCDS distillation
Requires less iterations and converges faster

6. Tower Plus Also uses the inside-out rigorous method
Allows for complex columns
This model is very difficult to converge and is often only used in petroleum and refining applications

7. Which Distillation Column to Choose?

8. Industrial Example
Plant operated by MOL Group, Hungarian Multinational Oil and Gas Company
Located in Algyõ, Hungary
Gas Distillation of Crude Oil
The distillation products are Propane, Propane-Butane mix, iso-Butane, normal-Butane, iso-Pentane and normal-Pentane. These are drawn off as top/bottom products from different columns in each train. The quantity and quality specification for each of these product streams changes with demand.
Trays Inside this tower and the lightweight gases move to the top
Image from:
Image from: emersonprocess.com

9. Example/Demo

10. Step 1: Open Workspace, Select Components

12. Step 2: Set Units and Flowsheet

13. Step 3: Run Flowsheet and Specify Recovery.

14. Step 4: Stream and Unit Op Reports

15. Stream Report

16. Unit-Op Report & Plots

17. References
NVERGENCE.pdf
ts/ProvenResults/OilGasRefining/RES_OG_MOL_Algyo_APC_Final_7-11.pdf

18. Questions