How air is collected and separated
Air is 78% nitrogen, and factories split it apart by cooling it until it turns to liquid.
- stations
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- things downstream
- 516
The short version
Industry takes air from the atmosphere by the millions of cubic meters. It is filtered, compressed, scrubbed of water and carbon dioxide, and chilled until it liquefies. In a tall distillation column, nitrogen, oxygen and argon boil off at different temperatures and are drawn off as separate gases.
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Filter and compress
Air is filtered for dust and then compressed. Typical pressures run between 5 and 10 bar gauge, and the compression supplies the energy that later drives refrigeration.
5 to 10 bar gauge
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Scrub out water and CO2
The compressed air passes through a bed of molecular sieve. It traps water vapor and carbon dioxide, which would freeze solid and plug the cold equipment.
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Chill it to liquid
Inside an insulated enclosure called a cold box, the air is cooled against the cold product streams until part of it liquefies. It is a delicate balance of heat exchangers and columns.
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Distill the gases apart
Nitrogen boils at 77.4 K, argon at 87.3 K and oxygen at 90.2 K, so the columns peel them off in order. Argon builds up in the middle of the low-pressure column, where a side draw collects it.
End of the lineAir
Next it goes into penicillin, insulin, mrna vaccine and 25 more.
Worth repeating
- Dry air is 78.08% nitrogen, 20.95% oxygen, 0.93% argon and 0.04% carbon dioxide by mole fraction.
- Carl von Linde developed the cryogenic process in 1895, and it stayed purely academic for seven years before its first industrial use in 1902.
- Neon, krypton and xenon can only be got by distilling air in at least two columns.
Where it goes next
Air feeds 28 lines directly and reaches 516 things in total.
PenicillinInsulinmRNA vaccineVitamin C tabletSulfuric acidNitric acidAmmoniaNitrogen gasOxygen gasABS plasticCarbon blackCarbon fiberPig ironCopperZincChromiumBasketballSoccer ballZinc oxideArgonPhenolHydrogen peroxideFormaldehydeNeonAcrylic acidPlasticizerAcetoneMercury
Further down the line
ShampooNail polishAspirinLaundry detergentFertilizerCar batteryAcetaminophenLEDBaking sodaHair dyeMemory chipWindow glassIncandescent light bulbPotato chipsBeef jerkyOffice chairFire extinguisherMicrochipOptical fiberOrbital rocketLipstickHearing aidDigital thermometerLEGO brick3D printer filamentLaptopTelevisionComputer keyboardComputer mouseHeadphonesRubik's CubeBallpoint penSnowboardAction figureHarmonicaDesk globeHard-shell suitcaseHigh heelsWireless earbudsPhone chargerUSB cableVideo game consoleWi-Fi routerE-readerInkjet printerGraphics cardRemote controlElectric toothbrushMascaraAA batteryTireHockey puckPrinter tonerHiking bootsRubber bootsVinyl recordWind turbineCamera droneSatelliteAirlinerBicycleTennis racketGolf clubFishing rodKiteProsthetic legCast iron panCar enginePianoDumbbellSailboatPrinted circuit boardLithium-ion cellElectric car batteryCamera sensorSolar panelRefrigeratorMicrowave ovenFaucetPadlockCoinGold ringAir conditionerFluteDie-cast toy carOlympic-style medalBronze bellStained glassLight switchPower outletBrake padSpark plugJeansSunscreenRebarNailScrewSteel pipeStapleBoltBarbed wireChain-link fenceSuspension bridge cableHip implantHard driveSafety pinRazor bladeTurbine bladeToasterIce skatesHeart stentWrenchFoundation makeupDouble-glazed windowNeon signBilliard ballBath towelSuper glueYoga matHairsprayVinyl flooringShoelaceEyeglass frameBreadInstant noodlesTortillaCroissantDonutPretzelSandwich cookieChicken nuggetsFrozen pizzaBagelBaguetteSourdough breadCrackersFish sticksModeling compoundLicoriceCake mixBleachNitrile glovePaintLCD screenSunglassesNonstick panRaincoatCanoeToothpasteCrayonEraserCandy-coated chocolatePVC pipeSewing needleJet engineTrumpetKeyCompact discSolar cellMirrorVacuum flaskSaxophoneSmoke detectorColaSodaAsthma inhalerTamponToothbrushAirbagAcoustic guitarViolinBike helmetHook-and-loop fastenerDishwasherRoller skatesVolleyballFashion dollUkuleleDrumstickEyeshadowDental flossAluminum window frameUnderwearLeggingsSwimsuitDown jacketLeather handbagBackpackFlagSocksCarpetZipperRopeAdhesive bandagePacemakerCarSkateboardSurfboardGolf ballHardwood flooringWater heaterSofaBowling ballWheelchairSneakerMattressGlass bottleSmartphone cover glassGlass marbleLED light bulbPinball machineSparkling waterRumLaminate flooringSmartphoneSolid-state driveSmartwatchDigital cameraSkyscraperWindshieldCredit cardElectric carElectric motorElectrical transformerVacuum cleanerMechanical wristwatchSteel I-beamRailroad railScissorsBall bearingContainer shipShipping containerLocomotiveMotorcycleElevatorDrum kitOak wine barrelSkiYo-yoHammerDrill bitGas cylinderSeat beltSubway trainLeather beltLoudspeakerSyringeWashing machineElectric kettleKitchen knifeStainless steel forkFountain penStainless steel water bottlePressure cookerBlenderBanknoteKitchen spongeSanitary padToilet paperFacial tissueDisposable diaperPencilTennis ballBaseballAmerican footballCricket batTreadmillAluminum ladderWheelbarrowLeather shoeUmbrellaPlastic bagTin canAluminum canPaper cupPizza boxWallpaperMarker penHighlighterFlying discBoard gameJigsaw puzzleTrading cardsCeramic floor tileFlip-flopsCardboard boxNewspaperBookSticky notesPlaying cardsT-shirtSaw bladeBlackboard chalkCandy caneSprinklesPlastic strawCeiling fanElectric guitarPower cableMicrophoneGarden hoseGuitar stringDoor hingeBronze statueShovelChess setGold barLeather glovesLeather walletEyeglass lensCamera lensSilk tiePlastic wrapInflatable pool toyDiceDeodorantWooden chairDartboardSnow globeCoil springDuct tapeFiberglass insulationMicrowave popcornPaper strawPaper bagWooden doorClear adhesive tapeCelloCotton swabAsphalt shingleDress shirtTailored suitEnvelopeMatchBaseball capChopsticksFelt hatBaseball batOLED screenGlass jarPerfumeKetchupBeerWineChampagneWhiskeyVodkaGinTequilaSakeHard ciderHot sauceRoot beerKombuchaTonic waterBourbonScotch whiskyCognacMezcalMeadPort wineProseccoNon-alcoholic beerCanned tunaAir freshenerWire ropePaperclipClothespinSlinkySteel chainPlastic bottleBottled waterSoapDrywallFireworksEgg cartonEnergy drinkCotton candyPillowCondensed milkBaby formulaCoconut milkCanned meatCanned soupLight beerInsect repellentCorn flakesCandleJarred salsaZip-top bagMouthwashCough syrupCondomContact lensWine corkMustardPicklesSauerkrautJamHazelnut spreadDish soapWet wipesHoodieCurtainsButtonTeddy bearToffeeMayonnaiseWool blanketWool sweater
Keep walking
Sources
Cite this page: "How air is collected and separated." Assembly Line, 2026-11-03. https://assemblyline.org/make/air