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

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

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, R min, and fractional recoveries, etc.

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

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

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

Which Distillation Column to Choose?

Industrial Example Plant operated by MOL Group, Hungarian Multinational Oil and Gas Company Located in Algyõ, Hungary Gas Distillation of Crude Oil Image from: emersonprocess.com Image from:

Example/Dem o

Step 1: Open Workspace, Select Components

Step 2: Set Units and Flowsheet

Step 3: Run Flowsheet and Specify Recovery.

Step 4: Stream and Unit Op Reports

Stream Report

Unit-Op Report & Plots

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

Questions