Introduction to Modelling Air Separation Units

Build, navigate and optimize a steady state simulation of an Air Separation Unit (ASU) using Aspen HYSYS. Utilize a wide variety of unit operation models and calculation tools to model process equipment. Use templates and sub-flowsheets to streamline and organize the different sections of the plant.


  • New Engineering graduates/technologists in ASU and cryogenic industry who will be using Aspen HYSYS in their daily work
  • Process engineers doing process design and optimization projects and studies of ASU / cryogenic plants
  • Plant engineers checking plant performance under different operating conditions
  • R&D engineers and researchers using Aspen HYSYS for ASU / cryogenic process design


Training Details

  • Course Id:


  • Duration:

    2 day(s)

  • CEUs Awarded:


  • Level:



  • Leverage the intuitive solving capabilities and other key features of Aspen HYSYS that allow for rapid flowsheet construction
  • Discover how multi-flowsheet integration can streamline and organize simulation efforts
  • Evaluate the performance of existing equipment by leveraging the equipment rating capabilities of Aspen HYSYS
  • Improve the convergence characteristics of columns and flowsheets; troubleshoot common problems
  • Perform Case Studies to determine the optimum operating points for a process


  • Instruction on basic topics
  • An experienced instructor will present modules in an appropriate order for maximum understanding
  • Discussion about the general approach and the key elements for the successful simulation of an ASU
  • Instructor-guided demonstrations of features
  • Hands-on workshops leading to the complete simulation of an ASU
  • Detailed course notes


  • Integrated Crude distillation preheat train overview in HYSYS
  • Convert the HYSYS Simulation to EO Sub-flowsheet
  • Compare performance difference between SM and EO Solvers
  • Use EO configuration group to change flowsheet solution
  • Perform sensitivity analysis


A background in chemical/process engineering (preferably with experience in cryogenic / ASU plant design or operation)

Subsequent Courses

  • EHY101: Aspen HYSYS: Process Modelling
  • EHY121 Building MS Excel User Interfaces for Aspen HYSYS Simulations Using Aspen Simulation Workbook
  • EHY202 Aspen HYSYS: Advanced Process Modeling Topics
  • EHY223 Aspen HYSYS Dynamics: Introduction to Dynamic Modeling


ASU Process Overview
  • Examine the Product requirements for the ASU plant to be simulated
  • Anaylze the proposed process design 
Getting Started
  • Enter necessary elements to fully define a Fluid Package 
  • Understand the relative volatility of components in the system
  • Investigate the phase behavior of typical fluids in the ASU process
Main Air Compressor (MAC)
  • Define the atmospheric air to be used as feedstock
  • Configure a 3-stage air compressor to produce Medium Pressure (MP) Air
Direct Contact After Cooler (DCAC) and Chilled Water Tower (ChWT)
  • Specify two Absorbers to represent the DCAC for MAC discharge air cooling
  • Use a Recycle option to link these two sections
  • Configure an additional column to create ChW for the DCAC, using cold Waste gas from the ASU
  • Use the Column Analysis tool to understand the ChWT hydraulics
Temperature Swing Adsorbers (TSA)
  • Use a component splitter to remove the moisture and carbon dioxide from the coldbox feed air.
Booster Air Compressor (BAC)
  • Split the dry air into process and utility streams
  • Configure a multi-stage compressor producing Intermediate Pressure (IP) Air for expansion and High Pressure (HP) Air for Liquid Air generation
  • Split the HP Air to the HP and Low Pressure (LP) column systems
Main Heat Exchanger (MHE) and Expander
  • Define a multi-stream Plate-Fin heat exchanger to cool the MP, IP and HP Air streams and recover refrigeration from the coldbox. 
  • Use an Expander model to remove energy from the IP Air stream, creating refrigeration.
Column System 
  • Configure a 2-column system (with a side operation, rectifier) to produce streams of the required product flow and composition.
  • Set up a Subcooler and Crude Argon Condenser
  • Fully define all column feed streams (using a Recycle where necessary -for further adjustment)
  • Install a pump to raise the Liquid Oxygen (LOX) pressure to product specification
Heat Integration
  • Integrate Crude Argon condenser (column system) into the Main flowsheet
  • Integrate column product streams into the MHE and Subcooler for refrigeration recovery
  • Link the HP Column condenser to the LP Column reboiler
  • Close heat and mass balance on the waste circuit
Product Compression and Storage
  • Route cryogenic liquid streams to storage
  • Perform ‘heat leak’ calculations on storage tanks
  • Configure a Gaseous Oxygen (GOX) pipeline
  • Use a multi-stage compressor model to compressor Gaseous Nitrogen (GAN) from coldbox to meet product specification
  • Use the HyproTech SQP optimizer to determine the optimum plant conditions to minimize energy usage.

Register for a Class

Date Class Type Location Price Language
Date(s): 11/8/2021 - 11/9/2021 Type: Public Virtual Location: Virtual-Americas Price: (USD) 1400.00 Language: English Register
Date(s): 02/7/2022 - 02/8/2022 Type: Public Virtual Location: Virtual-Americas Price: (USD) 1400.00 Language: English Register
Date(s): 05/9/2022 - 05/10/2022 Type: Public Virtual Location: Virtual-Americas Price: (USD) 1400.00 Language: English Register
Date(s): 08/8/2022 - 08/9/2022 Type: Public Virtual Location: Virtual-Americas Price: (USD) 1400.00 Language: English Register
Date(s): 11/7/2022 - 11/8/2022 Type: Public Virtual Location: Virtual-Americas Price: (USD) 1400.00 Language: English Register

Aspen Technology, Inc. awards Continuing Education Units (CEUs) for training classes conducted by our organization. One CEU is granted for every 10 hours of class participation.