How to simulate ethanolamines plant: mea / dea / tea from ethylene oxide + ammonia
The nitrogen analogue of the ethylene-glycol chain, and a major gas-treating-solvent process in its own right. Ethylene oxide reacts with ammonia through the same kind of CONSECUTIVE addition chain the glycols follow — EO + NH₃ → monoethanolamine (MEA), EO + MEA → diethanolamine (DEA), EO + DEA → triethanolamine (TEA), all atom-balanced and keyed on the shrinking EO pool. A large ammonia excess pushes selectivity toward MEA (the ~80/13/5 MEA/DEA/TEA slate a high NH₃:EO ratio makes, amine-side mirror of how a high water:EO ratio favours MEG). The separation strips the excess ammonia (recovered for recycle) and the reaction water, then splits the amines by boiling point (MEA 170 C < DEA 269 C < TEA 335 C) into ~99.8% MEA, high-purity DEA, and a TEA bottoms cut. HONEST SCOPE: the reaction chemistry is rigorous stoichiometry (real atom balances, realistic selectivity from the fixed conversions), and the amines are characterized as pseudo-components (Tc/Pc/omega from the open-data databank — MEA/DEA/TEA have no CoolProp entry) so they flash under Peng-Robinson. The purification uses spec-based component-split separators (the Aspen 'Sep'-block technique), NOT rigorous vacuum columns — the ethanolamines are wide-boiling with narrow adjacent-amine relative volatilities, the same wide-boiling-MESH limit measured for the glycol columns. The recovered ammonia is shown as an open recycle stream (an honest simplification, like the parent EO example).
- 1Open the ready-made model
Open the "Ethanolamines plant: MEA / DEA / TEA from ethylene oxide + ammonia" 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 PENG-ROBINSON property package over ethylene_oxide, ammonia, monoethanolamine, diethanolamine, triethanolamine, water — already selected, so the phase equilibrium and enthalpy are physically consistent from the first run.
- 3Review the flowsheet
The flowsheet chains MIX, 3× RXN3, COOL, 4× Deacol. 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
- PENG-ROBINSON
- Components
- ethylene_oxide, ammonia, monoethanolamine, diethanolamine, triethanolamine, water
- Unit operations
- MIX3× RXN3COOL4× Deacol
Opens live on the canvas — free, no install.
Explore the model & flowsheetFrequently asked questions
- What does the Ethanolamines plant: MEA / DEA / TEA from ethylene oxide + ammonia model simulate?
- The nitrogen analogue of the ethylene-glycol chain, and a major gas-treating-solvent process in its own right. Ethylene oxide reacts with ammonia through the same kind of CONSECUTIVE addition chain the glycols follow — EO + NH₃ → monoethanolamine (MEA), EO + MEA → diethanolamine (DEA), EO + DEA → triethanolamine (TEA), all atom-balanced and keyed on the shrinking EO pool. A large ammonia excess pushes selectivity toward MEA (the ~80/13/5 MEA/DEA/TEA slate a high NH₃:EO ratio makes, amine-side mirror of how a high water:EO ratio favours MEG). The separation strips the excess ammonia (recovered for recycle) and the reaction water, then splits the amines by boiling point (MEA 170 C < DEA 269 C < TEA 335 C) into ~99.8% MEA, high-purity DEA, and a TEA bottoms cut. HONEST SCOPE: the reaction chemistry is rigorous stoichiometry (real atom balances, realistic selectivity from the fixed conversions), and the amines are characterized as pseudo-components (Tc/Pc/omega from the open-data databank — MEA/DEA/TEA have no CoolProp entry) so they flash under Peng-Robinson. The purification uses spec-based component-split separators (the Aspen 'Sep'-block technique), NOT rigorous vacuum columns — the ethanolamines are wide-boiling with narrow adjacent-amine relative volatilities, the same wide-boiling-MESH limit measured for the glycol columns. The recovered ammonia is shown as an open recycle stream (an honest simplification, like the parent EO example).
- Which thermodynamic method does it use?
- The PENG-ROBINSON property package, over ethylene_oxide, ammonia, monoethanolamine, diethanolamine, triethanolamine, water — already selected. You can switch the method on the canvas before running.
- Which unit operations are in the flowsheet?
- It chains MIX, 3× RXN3, COOL, 4× Deacol. 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. Ethanolamines plant: MEA / DEA / TEA from ethylene oxide + ammonia runs entirely in your browser on MaximaLabs — free, no install, no license. Open the model to load it live and run the deterministic solver.
More guides like this
Ethylene glycol plant: fiber-grade MEG + DEG/TEG byproducts
Extends the EO/glycol chain all the way to separated products. Ethylene + O₂ make ethylene oxide over a silver catalyst (with the competing total-combustion side reaction), EO condenses out, and then hydrates through the real CONSECUTIVE glycol reactions — EO + H₂O → MEG, EO + MEG → DEG, EO + DEG → TEG (all atom-balanced, keyed on the shrinking EO pool) — giving the industrial ~90/9/1 mono-/di-/tri-ethylene-glycol selectivity that a high water:EO ratio produces. The purification train recovers the water for recycle and splits the glycols into fiber-grade MEG (>=99.9%), DEG, and TEG products. HONEST SCOPE: the reaction chemistry is rigorous stoichiometry (real atom balances, realistic selectivity set by the fixed conversions); the PURIFICATION is modelled with spec-based component-split separators to the known product purities (the Aspen 'Sep'-block technique for a well-understood separation section), NOT rigorous vacuum distillation columns — a converged 99.9%-fiber-grade MEG column is not tractable in this solver under Peng-Robinson (the MEG/DEG relative volatility is too narrow for the wide-boiling MESH path; a real plant uses large multi-effect evaporators + vacuum columns). The water-recycle stream is left open (not looped back) — an honest simplification, like the parent EO example's ethylene recycle.
Ethylene glycol plant: closed water loop + multi-effect evaporator dehydration
The water-integrated evolution of the fiber-grade MEG plant. Two changes turn the once-through EO/glycol chain into a real, water-economical process: (1) the recovered process water is RECYCLED back to the hydration reactors through a purge splitter. A pure recycle is inventory-singular (reactors are keyed on the shrinking EO pool, so water consumption is fixed regardless of how much water circulates), so an 8% purge pins the loop and makes it well-posed, cutting fresh water makeup from 10 to ~1.75 mol/s (a >80% reduction). (2) The bulk dehydration is done by a genuine TWO-EFFECT EVAPORATOR TRAIN (forward-feed, real steam economy: effect 1's low-temperature vapor is the heating steam for effect 2) doing rigorous (P,H)-flash water removal, rather than a single spec-based split. The recycle converges through the solver's Wegstein tearing (~15 outer passes) and MEG still comes out fiber-grade (>=99.9%). HONEST SCOPE: the reaction chemistry is rigorous stoichiometry (real atom balances, ~90/9/1 selectivity) and the evaporators are real energy-balanced flash effects — but flash evaporation CANNOT reach glycol dryness without slipping glycol into the overhead vapor (MEG has a real vapor pressure at 90 C), so the evaporators run cool and only pre-concentrate. An overhead knockout returns the ~1-2% slipped glycol to the product (no yield loss), and a final vacuum-refining polish (still a spec-based split, representing the refluxed dehydration column a flash cannot replicate) removes the last water. This mirrors a real MEG plant's multi-effect-evaporator + vacuum-refining dehydration section. The product columns remain spec-based (a converged 99.9% fiber-grade MEG column is not tractable under Peng-Robinson here — the MEG/DEG relative volatility is too narrow for the wide-boiling MESH path).
Pressure-swing ethanol dehydration (Gᴱ mixing rule)
Ethanol–water is the classic azeotrope, and pressure-swing distillation breaks it without an entrainer: the azeotrope moves with pressure, so a low-pressure column and a high-pressure column pass each other's azeotropic distillate and each recovers a pure product. The whole process only works if the property package tracks that shift — which is exactly where a conventional package choice falls between two chairs. This flowsheet runs the high-pressure column at 15 bar on pr-mhv1: Peng-Robinson with an MHV1 excess-Gibbs mixing rule, so the cubic equation of state gets its attraction parameter from NRTL's excess Gibbs energy instead of from a single binary interaction constant. Switch the thermo package (Solver menu) and compare the predicted azeotrope: | package | 1 atm | 15 bar | valid at 15 bar? | |---|---|---|---| | NRTL | 0.891 | 0.802 | no — γ-φ is a low-pressure formulation (~10 bar) | | Peng-Robinson (kij) | 0.586 | 0.613 | yes, but a kij cannot represent this azeotrope | | pr-mhv1 | 0.949 | 0.798 | yes | (mole fraction ethanol; the repo's DECHEMA-validated 1 atm anchor is 0.894.) At 15 bar pr-mhv1 lands within 0.005 of NRTL while remaining a genuine equation of state, whereas plain Peng-Robinson is off by ~0.19 and puts the azeotrope in the wrong place entirely. Selecting nrtl here also trips the applicability guard, which warns that the activity model is past its pressure ceiling and names the fix. The flowsheet demonstrates the mechanism on itself. Drop the column pressure to 1 atm and re-run, changing nothing else: the solve fails with SPEC_THERMODYNAMICALLY_IMPOSSIBLE, because at atmospheric pressure the requested bottoms purity sits beyond the azeotrope and no column can reach it. At 15 bar the same specification converges and the bottoms leaves at x_EtOH ≈ 0.924 — past the atmospheric azeotrope of 0.894, which is precisely the composition an atmospheric column cannot cross.
Industrial water reuse: RO + membrane distillation to near-ZLD
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