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Recycle Process Flowsheets & Simulations

Explore 7 validated, solved Recycle simulation flowsheets in MaximaLabs — real components: water, propane, ammonia, helium, 1_butene, isobutane. Open any one directly in your browser.

Solved via: NRTL, COOLPROP, PENG-ROBINSON.

FEED
MIX
HEAT
Split
PROD
Reference model

Recycle loop

A mixer/heater/splitter loop with a tear stream — exercises Wegstein recycle convergence.

5 unit ops • NRTL

20 3

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FEED
MIX
COMP
COND
Valve
EVAP
Split
Purge
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).

8 unit ops • COOLPROP

17 0

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FEED
MIX
COMP
COND
Valve
EVAP
Split
Purge
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).

8 unit ops • COOLPROP

17 0

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⭐ Featured
FEED
MIX
COMP
COOL
Precool
JT
Flash
LHE
Amarillo, Texas, USA

Helium liquefaction (Linde-Hampson cycle)

A Joule-Thomson liquefaction loop: helium is compressed, aftercooled, precooled well below its ~40-51 K JT-inversion temperature, then throttled through a valve into a flash drum that draws off liquid helium while the cold vapor recycles back to the compressor suction — the same JT-cycle physics as the platform's LNG/refrigeration loops, run on a fluid whose inversion curve makes precooling mandatory before the throttle can cool it at all.

8 unit ops • COOLPROP

17 0

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Butene
Isobutane Makeup
MIX
RXN
feed
dist
btms
DIB
Alkylate
Reference model (Luyben 2009/2011)

Butene/isobutane alkylation

Sulfuric-acid alkylation of butene with excess isobutane produces high-octane alkylate gasoline blendstock; a conversion reactor stands in for the acid-catalyzed carbocation chemistry (a literal acid/hydrocarbon settler would need H2SO4 electrolyte thermodynamics this package doesn't carry — out of scope, same as the reactor already being a stand-in for the chemistry itself), and a deisobutanizer-style column recovers unreacted isobutane overhead. The high isobutane:olefin ratio real alkylation units run is maintained almost entirely by recycling that isobutane back to the reactor feed — closed here as a real Wegstein-converged tear loop, with only a small makeup feed replacing what the reaction actually consumes, rather than the previous version's isobutane leaving as an unrecycled product. Luyben, Principles and Case Studies of Simultaneous Design, Wiley (2011); Ind. Eng. Chem. Res. 2009, 48, 11081.

6 unit ops • PENG-ROBINSON

17 0

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OIL FEED
H2 Makeup
MIX
Fired Heater
HDT Reactor
HOT HP SEP
COOL
COLD HP SEP
Amine Absorber
H2S Product
Recycle Split
Purge
Recycle COMP
Liquid MIX
Letdown
feed
dist
btms
Stripper
Stripper Overhead
Hydrotreated Diesel
Port Arthur, Texas, USA

Diesel hydrotreater with closed H2 recycle + amine wash

Diesel (an n-hexadecane carrier with a dibenzothiophene sulfur slice) and hydrogen react over a trickle-bed-equivalent reactor (dibenzothiophene + 3H2 -> biphenyl + H2S, the real HDS desulfurization route) after a fired-heater preheat. Hot and cold high-pressure separators knock the light gas off the treated oil; an amine wash (a fixed-recovery separator — the same simplification the existing carbon-capture example uses, not a full electrolyte amine model) scrubs H2S from the recycle gas before a compressor closes the loop back to the reactor feed, with a small purge controlling buildup. A pressure-letdown valve + stripper finish the treated oil, removing dissolved light ends before the desulfurized diesel leaves the bottoms.

18 unit ops • PENG-ROBINSON

19 0

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⭐ Featured
Erlangen, Germany

LOHC hydrogen release (methylcyclohexane dehydrogenation)

A liquid organic hydrogen carrier (LOHC) power train: methylcyclohexane (MCH) is preheated and catalytically dehydrogenated (MCH -> toluene + 3H2, endothermic, equilibrium-limited to ~90% single-pass conversion) to release hydrogen for downstream power generation. A flash drum separates the H2-rich gas from the liquid; a distillation column then recovers the unreacted MCH overhead and recycles it to the reactor feed, closing a real tight liquid recycle loop, while spent toluene leaves the bottoms (to be re-hydrogenated back to MCH off-site, closing the supply-chain loop — out of scope for this dehydrogenation-side flowsheet). Screening-fidelity note: MCH and toluene are genuinely close-boiling (relative volatility ~1.4 under this thermo package at column conditions), so the recycle carries real toluene along with the recovered MCH rather than a sharp cut — a production column would use more stages to purify it further; this shows the recycle topology and its convergence, not an optimized column design.

8 unit ops • PENG-ROBINSON

18 0

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