⚙ Choosing the Right Thermodynamic Property Package in Aspen HYSYS 

A Technical Guide for Process Engineers 

In Aspen HYSYS, choosing the correct thermodynamic property package is critical for accurate simulation, particularly in oil & gas, petrochemical, and chemical processing applications. This isn’t just a formality—your simulation’s reliability depends on it. 

🔍 Where It All Begins: Understanding Your System 

The nature of your components—polar vs. non-polar—and the operating conditions (e.g., high pressure, near critical point) guide the choice of property package. Use the decision flowchart below to make an informed selection: 

📌 Reference Flowchart: 

🔧 Why the Choice Matters 

Each property package is built on different thermodynamic models: 

• PR (Peng-Robinson) – Ideal for hydrocarbon systems at high pressure. 

• PRSV – A modified version of PR for better vapor-liquid predictions. 

• NRTL & Activity Models – Best for polar, non-ideal, or highly associating mixtures like water-alcohol or acid-base systems. 

• Lee-Kesler-Plocker – Great for light hydrocarbon gases like ethylene. 

• Steam Package – Specifically designed for water/steam thermodynamics. 

📊 Practical Reference Table from Industry 

For commonly simulated systems, here’s a table of recommended property packages used by engineers in Aspen HYSYS: 

📌 Industrial Property Package Recommendations 

Type of System	Recommended Property Package
TEG Dehydration	PR
Sour Water	PR, Sour PR
Cryogenic Gas Processing	PR, PRSV
Air Separation	PR, PRSV
Atm Crude Towers	PR, PR Options, GS
Vacuum Towers	PR, PR Options, GS (<10 mm Hg), Braun K10, Esso K
Ethylene Towers	Lee Kesler Plocker
High H₂ Systems	PR, ZJ or GS (see T/P limits)
Reservoir Systems	PR, PR Options
Steam Systems	Steam Package, CS or GS
Hydrate Inhibition	PR
Chemical Systems	Activity Models, PRSV
HF Alkylation	PRSV, NRTL (Contact Hyprotech)
TEG Dehydration with Aromatics	PR (Contact Hyprotech)

🛠️ Detailed Examples & Recommendations 

🔸 Cryogenic Gas Processing 

• Use: PRSV 

• Why: Better VLE prediction at low temperature & high pressure 

• Tip: Always validate phase envelopes to ensure proper condensation of methane/ethane. 

🔸 Sour Water Stripper 

• Use: Sour PR 

• Why: It accounts for ionic dissociation and acid gas solubility 

• Note: Works best when combined with proper pH and aqueous specs. 

🔸 Atmospheric and Vacuum Crude Distillation 

• Use: PR, GS, or Braun K10 for deep vacuum 

• Why: GS handles wide boiling range components better. 

• Trick: Switch to Esso K for ultra-low-pressure conditions (<10 mmHg). 

🔸 Ethylene Production Columns 

• Use: Lee-Kesler-Plocker 

• Why: Ideal for light gas hydrocarbon systems 

• Caution: Do not use PR for ethylene or propylene recovery—errors can be large. 

🔸 HF Alkylation 

• Use: PRSV + NRTL (with vendor support) 

• Why: Strong non-ideality with HF-water-organic mix 

• Best Practice: Use data provided by licensor or vendor (Hyprotech). 

✅ Quick Engineering Checklist 

✔️ Are there polar components (e.g., water, alcohols, acids)? 
→ Use activity coefficient models like NRTL or UNIQUAC. 

✔️ Is it a hydrocarbon system under pressure? 
→ Use Equation of State models like PR or PRSV. 

✔️ Are you near the critical region or dealing with light gases? 
→ Use Lee-Kesler-Plocker or specialized EOS models. 

✔️ For chemical reactors with electrolyte behavior? 
→ Use NRTL with Henry’s Law or activity models. 

📣 Final Thought 

A small mistake in selecting your property package can result in large simulation errors. Use this blog as your engineering-ready reference to build reliable, real-world HYSYS models.