Recycle Process Flowsheets & Simulations
Explore 8 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.
Recycle loop
A mixer/heater/splitter loop with a tear stream — exercises Wegstein recycle convergence.
5 unit ops • NRTL
227 5
View & openPropane 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
223 0
View & openAmmonia 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
224 0
View & openHelium 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
223 0
View & openButene/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
224 0
View & openDiesel 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
227 0
View & openLOHC 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
226 0
View & openHydrogen liquefaction with catalytic ortho-para conversion
A Linde-Hampson JT-cycle liquefaction loop for H₂ (the same recycle topology as helium-liquefaction), but H₂'s real liquefaction process needs one more step helium doesn't: normal H₂ feed is ~75% ortho-/25% para-spin-isomer, while the equilibrium mix at liquid-H₂ temperature is ~99.8% para — liquefying without converting first leaves the ortho fraction far above its new equilibrium value, and its slow natural relaxation releases heat (the textbook explanation for uncatalyzed LH2 tanks self-boiling). This closes a real gap: (a catalytic cold-box converter, real equilibrium-para-fraction statistical mechanics) existed in MaximaLabs but was never wired into a showcase example — and turned out to also be missing from the backend's unit-type validation catalog entirely (fixed alongside this example,). Precooling to 30 K (deep enough that H₂'s JT effect actually condenses it — verified numerically: 77 K/60 K/45 K precool all give zero liquid yield at 20 atm → 1.3 atm here, since H₂'s JT-cooling window needs real precooling well below LN2 temperature, unlike simpler gases) also happens to sit right where the ortho-para conversion actually matters.
9 unit ops • COOLPROP
192 1
View & open