How to simulate acetic acid recovery — nrtl with vapor-phase dimerization
Concentrating dilute aqueous acetic acid (30 mol%) to a 99.8% acetic-acid bottoms product by distillation, modeled with the NRTL activity package and **chemical-theory vapor-phase association** (acetic acid dimerizes, 2 A → A2, in the vapor). This is the physics a cubic equation of state gets wrong: the pinned NRTL acetic-acid/water binary (DECHEMA) plus the cited dimerization constants (Nagy et al., Molecules 2020) give the real bubble curve and latent heat, so the close-boiling acid/water pair actually separates and converges where Peng-Robinson does not.
- 1Open the ready-made model
Open the "Acetic acid recovery — NRTL with vapor-phase dimerization" model in the MaximaLabs workspace — no install, no license. It loads live on the canvas, ready to edit and run.
- 2Confirm the thermodynamics
This process is modeled with the NRTL-ASSOCIATE property package over acetic_acid, water — already selected, so the phase equilibrium and enthalpy are physically consistent from the first run.
- 3Review the flowsheet
The flowsheet chains COL. Every block is a real, solvable unit op you can reconfigure on the canvas.
- 4Run the simulation
Click Run. The deterministic solver converges the material and energy balances (recycles included) and fills the live stream table — the AI never invents a number.
- 5Read the results and iterate
Inspect the converged streams, tweak a spec, and re-run — or ask the AI copilot to explain a result or diagnose a failed solve in plain English.
- Thermodynamics
- NRTL-ASSOCIATE
- Components
- acetic_acid, water
- Unit operations
- COL
Opens live on the canvas — free, no install.
Explore the model & flowsheetModeling assumptions & limitations
What this model captures, and what it deliberately does not — from the engineers who built it.
- 1Acetic acid and water are close-boiling with no azeotrope, so the water distillate is only ~87% water (the acid product is the concentrated, high-purity stream); a sharper water cut needs more stages / reflux than this screening case uses.
Frequently asked questions
- What does the Acetic acid recovery — NRTL with vapor-phase dimerization model simulate?
- Concentrating dilute aqueous acetic acid (30 mol%) to a 99.8% acetic-acid bottoms product by distillation, modeled with the NRTL activity package and **chemical-theory vapor-phase association** (acetic acid dimerizes, 2 A → A2, in the vapor). This is the physics a cubic equation of state gets wrong: the pinned NRTL acetic-acid/water binary (DECHEMA) plus the cited dimerization constants (Nagy et al., Molecules 2020) give the real bubble curve and latent heat, so the close-boiling acid/water pair actually separates and converges where Peng-Robinson does not.
- Which thermodynamic method does it use?
- The NRTL-ASSOCIATE property package, over acetic_acid, water — already selected. You can switch the method on the canvas before running.
- Which unit operations are in the flowsheet?
- It chains COL. Every block is a real, solvable unit operation you can reconfigure, add to, or remove.
- Do I need to install software or buy a license?
- No. Acetic acid recovery — NRTL with vapor-phase dimerization runs entirely in your browser on MaximaLabs — free, no install, no license. Open the model to load it live and run the deterministic solver.
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