Which thermodynamic method does it use?

The PENG-ROBINSON property package, over methane, ethane, propane, n_butane, n_pentane, co2, n2 — already selected. You can switch the method on the canvas before running.

Which unit operations are in the flowsheet?

It chains Coldbox, Coldsep. 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. Cold-separator NGL recovery / dew-point control runs entirely in your browser on MaximaLabs — free, no install, no license. Open the model to load it live and run the deterministic solver.

All guides

Gas processing (cold-separator dew-point control)

How to simulate cold-separator ngl recovery / dew-point control

A rich natural gas is chilled in the gas/gas exchanger + propane-chiller train (lumped here as one cold box) to -33 degC and let into a cold separator. The heavy hydrocarbons (C3+) drop out as a raw NGL liquid, leaving a leaner sales gas that meets its hydrocarbon dew-point spec — so no more liquid forms as the gas cools in the export pipeline. The cold separator is modelled as an adiabatic flash fed by the chiller, so the single knob (the chill temperature) drives both the NGL recovered and the refrigeration duty: colder recovers more NGL but costs more refrigeration (the built-in sensitivity). Peng-Robinson handles the hydrocarbon VLE; the companion gas-conditioning utilities (hydrate risk, water content, Joule-Thomson choke cooling, and compressor sizing for the sales-gas recompression) quantify the rest of the plant around it.

Richgas

Coldbox

Coldsep

Salesgas

Rawngl

1
Open the ready-made model
Open the "Cold-separator NGL recovery / dew-point control" model in the MaximaLabs workspace — no install, no license. It loads live on the canvas, ready to edit and run.
2
Confirm the thermodynamics
This process is modeled with the PENG-ROBINSON property package over methane, ethane, propane, n_butane, n_pentane, co2, n2 — already selected, so the phase equilibrium and enthalpy are physically consistent from the first run.
3
Review the flowsheet
The flowsheet chains Coldbox, Coldsep. Every block is a real, solvable unit op you can reconfigure on the canvas.
4
Run 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.
5
Read 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.

What you'll build

Thermodynamics: PENG-ROBINSON
Components: methane, ethane, propane, n_butane, n_pentane, co2, n2
Unit operations: ColdboxColdsep

Open this model in the workspace

Opens live on the canvas — free, no install.

Explore the model & flowsheet

Frequently asked questions

What does the Cold-separator NGL recovery / dew-point control model simulate?: A rich natural gas is chilled in the gas/gas exchanger + propane-chiller train (lumped here as one cold box) to -33 degC and let into a cold separator. The heavy hydrocarbons (C3+) drop out as a raw NGL liquid, leaving a leaner sales gas that meets its hydrocarbon dew-point spec — so no more liquid forms as the gas cools in the export pipeline. The cold separator is modelled as an adiabatic flash fed by the chiller, so the single knob (the chill temperature) drives both the NGL recovered and the refrigeration duty: colder recovers more NGL but costs more refrigeration (the built-in sensitivity). Peng-Robinson handles the hydrocarbon VLE; the companion gas-conditioning utilities (hydrate risk, water content, Joule-Thomson choke cooling, and compressor sizing for the sales-gas recompression) quantify the rest of the plant around it.
Which thermodynamic method does it use?: The PENG-ROBINSON property package, over methane, ethane, propane, n_butane, n_pentane, co2, n2 — already selected. You can switch the method on the canvas before running.
Which unit operations are in the flowsheet?: It chains Coldbox, Coldsep. 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. Cold-separator NGL recovery / dew-point control 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

NGL recovery plant, Permian Basin, Texas, USA

Deep ethane recovery with propane-refrigerated feed chilling

Associated gas is chilled by an external propane refrigeration package before a demethanizer recovers ethane and heavier as NGL bottoms from a methane-rich residue gas overhead — the cryogenic-chilling role Ortloff's CCS/GSP processes play ahead of the turboexpander in a real deep-ethane-recovery plant. The mechanical refrigeration loop itself (compressor/condenser/valve) isn't separately modeled here; the chiller's duty is represented directly as the feed's cooled outlet temperature (the same honest-simplification pattern used for LNG cold-box examples elsewhere in this library).

Permian Basin, Texas, USA

Associated gas conditioning

Field gas is compressed, chilled below its dew point, and flashed to knock out NGL/condensate — the sales-gas vs. liquids split every midstream gathering plant runs (Peng-Robinson).

Reference model

Gas compressor air-cooled aftercooler (fin-fan)

A natural-gas booster compressor followed by an air-cooled (fin-fan) aftercooler — the standard way to reject compression heat where no cooling water is available. The compressor raises the gas from 8 to 24 atm (hot discharge ~150 °C); the air cooler then rejects that heat to ambient air, cooling the gas back to 49 °C. Unlike a plain cooler, the air_cooler op closes the air side: from the process duty and the 35 °C design ambient it solves the air mass flow (a 15 °C air rise) and reports the fan power from the given fan static pressure. Honest scope: screening air-side model (fixed cp_air, ideal-gas air density, no fin/row geometry rating); an air cooler cannot cool below ambient, so the 49 °C target sits safely above the 35 °C air inlet.

Reference model (ChemSep)

Propane refrigeration cycle

A single-stage vapor-compression refrigeration loop: propane vapor is compressed, condensed to subcooled liquid, throttled through a valve, and superheated back to vapor in the evaporator before recycling — a small makeup feed and purge close the mass balance (inspired by ChemSep's Refrigeration_* reference cases).

Reference model (ChemSep)

Ammonia refrigeration cycle

A single-stage vapor-compression refrigeration loop using ammonia — the classic industrial (rather than HFC) refrigerant — condensed to subcooled liquid, throttled through a valve, and superheated back to vapor in the evaporator before recycling (inspired by ChemSep's Refrigeration_Ammonia-30C reference case).

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Natural gas fractionation train

A four-column NGL fractionation train — demethanizer, deethanizer, depropanizer, debutanizer — recovering pipeline-spec sales gas plus ethane, propane, and butane products from wellhead-pressure raw natural gas, after Luyben (Ind. Eng. Chem. Res. 2013, 52, 10741).