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JohnJechura [email protected]:June29,2014
CrudeDistillationChapter4
Light Naphtha
CrudeOil
Desalter
Atmospheric Distillation
Vacuum Distillation
Gas Separation &
Stabilizer
Solvent Deasphalting
Coking
Visbreaking
Fluidized Catalytic Cracking
Hydro-cracking
NaphthaReforming
Isom-erization
Sat Gas Plant
Polymer-ization
Alkylation
NaphthaHydro-treating
Treating & Blending
Coke
Fuel Gas
LPG
Aviation Gasoline
Automotive Gasoline
Solvents
Jet Fuels
Kerosene
Solvents
Heating Oils
Diesel
ResidualFuel Oils
Lubricant
Greases
Waxes
Asphalts
HeavyNaphtha
Kerosene
DistillateAGO
LVGO
HVGO
VacuumResiduum
CatDistillates
Gas Oil Hydro-treating
DAO
Isomerate
Gas
AlkylFeed
Alkylate
PolymerizationNaphtha
Gases
Butanes
LPG
Reformate
Naphtha
Fuel OilBottoms
Distillates
DistillateHydro-treating
CatNaphtha
Cycle Oils
SDABottomsCokerNaphtha
HeavyCokerGasOil
Light CokerGas Oil
SulfurPlant Sulfur
Naphtha
Fuel Oil
SolventDewaxing
Lube Oil
Waxes
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20LargestAtmosphericComplexesinU.S.
3
EIA,Jan.1,2014database,publishedJune2014http://www.eia.gov/petroleum/refinerycapacity/
Topics
CrudeStills Historicallytheoldestrefiningprocess Onlythefirststepincrudeoilprocessing
Purpose Torecoverlightmaterials Fractionateintosharplightfractions
ConfigurationMaybeasmanyasthreecolumnsinseries CrudeStabilizer/Preflash Column
ReducetrafficintheAtmosphericColumn
AtmosphericColumn VacuumColumn
Reducedpressuretokeeptemperaturesbelow650F ProductYieldCurves CutPoint,Overlap,&Tails
4
Topics
CrudeStills Historicallytheoldestrefiningprocess Onlythefirststepincrudeoilprocessing
Purpose Torecoverlightmaterials Fractionateintosharplightfractions
ConfigurationMaybeasmanyasthreecolumnsinseries CrudeStabilizer/Preflash Column
ReducetrafficintheAtmosphericColumn
AtmosphericColumn VacuumColumn
Reducedpressuretokeeptemperaturesbelow650F ProductYieldCurves CutPoint,Overlap,&Tails
5
Topics
CrudeStills Historicallytheoldestrefiningprocess Onlythefirststepincrudeoilprocessing
Purpose Torecoverlightmaterials Fractionateintosharplightfractions
ConfigurationMaybeasmanyasthreecolumnsinseries CrudeStabilizer/Preflash Column
ReducetrafficintheAtmosphericColumn
AtmosphericColumn VacuumColumn
Reducedpressuretokeeptemperaturesbelow650F ProductYieldCurves CutPoint,Overlap,&Tails
6
Atmospheric&VacuumTowerComplex
7
Atmospheric&VacuumTowerComplex
8
KochGlitsch BulletinKGSS1,Rev.32010,http://www.kochglitsch.com/Document%20Library/KGSS.pdf
AtmosphericColumnw/oPreflash
9
BasedonfigurefromRefiningOverview PetroleumProcesses&Products,byFreemanSelf,EdEkholm,&KeithBowers,AIChE CDROM,2000
FeedPreheatTrain&Desalter
FeedPreheatTrain Initialheatexchangewithstreamsfromwithinthetower Heatrecoveryimportanttodistillationeconomics!o Firstabsorbpartoftheoverheadcondensationload
o Exchangewithoneormoreoftheliquidsidesstreams,beginningwiththetop(coldest)sidestream
Requireflexibilityo Changesincrudeslateo Temperatureatdesaltero Limitsontwophaseflowthroughnetwork
Finalheatinginadirectfiredheater Heatenoughtovaporizelightportionsofthecrudebuttemperaturekeptlowtominimizethermalcrackingo Inlettypically550Fo Outlet600to750F.
Heaviercrudescannotbeheatedtothehighertemperatures
Desalter Temperaturecarefullyselected donotletwatervaporize Lightercrudes(>40API)@250F Heaviercrudes(
CrudeElectrostaticDesalting
11
BFDsfrom:RefiningOverview PetroleumProcesses&Products,byFreemanSelf,EdEkholm,&KeithBowers,AIChE CDROM,2000
DrawingbyMiltonBeychokhttp://en.citizendium.org/wiki/File:Desalter_Diagram.png
ExampleCrudePreheatTrains
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Ref:DebottleneckcrudeunitpreheatexchangernetworkinefficienciesBright,Roy&AlZahrani,HydrocarbonProcessing,February2012
DirectFiredHeater
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Ref:UsefultipsforfiredheateroptimisationBishop&Hamilton,PetroleumTechnologyQuarterly,Q22012
AtmosphericDistillationSummary Condenser
PartialcondenserifnoStabilizerColumn.
TotalcondenserifStabilizerColumntoremovelightends.
butnoreboiler. Feedpreheatexchangertrain Alloftheheattodrivethecolumncomesfromthehotfeed.
Asmuchas50%oftheincomingcrudemaybeflashed.
Overflasho Extraamountofmaterialvaporizedto
ensurerefluxbetweenflashzone&lowestsidedraw
o Typically2vol%offeed
Pumparounds Movecoolingdowncolumn. Liquidreturnedabovedrawtray
Sidedraws
Sidestrippers Cleanupsideproducts
Strippingsteam Reducehydrocarbonpartialpressure Condensed&removedasasecondliquidphase.
Conditionssetsoitdoesntcondensewithinthecolumn canleadtofoaming
Mustbetreatedassourwater
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AtmosphericDistillationSummary WashZone
Coupletraysbetweenflashzone&gasoildraw.
Refluxtowashresins&otherheavymaterialsthatmaycontaminatetheproducts.
Condenser Typically0.5to20psig. Balancingact
Lowpressuresreducecompressiononoverheadsystem
Highpressuresdecreasevaporizationbutincreaseflashzonetemperatures&furnaceduty;affectsyields
Pumparounds Reducesoverheadcondenserload&achievesmoreuniformtowerloadings
Providesliquidrefluxbelowliquiddraws
SideDraws&Strippers Sidestrippersremovelightcomponenttail&returntomaincolumn
Steamstripperstraditional Reboiled strippersreduceassociatedsourwater&mayreducesteamusage
Trays&PressureProfile Typically32traysintower 0.1psipertrayfordesign&targetforoperation
Mayfindashighas0.2psipertray,butprobablyflooding!
Condenser&accumulator 3to10psiacrosscondenser
Liquidstaticheadinaccumulator
Typically6to16psiacrossentirecolumn.
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VacuumDistillation
16
RefiningOverview PetroleumProcesses&Products,byFreemanSelf,EdEkholm,&KeithBowers,AIChE CDROM,2000
ConsiderpracticalconditionsforvacuumunitmodelingR.Yahyaabadi,HydrocarbonProcessing,March2009
VacuumDistillationSummary ColumnConfiguration
Vacuumconditionstokeepoperatingtemperatureslow
Largediametercolumn Verylowdensitygases Condenseronlyforwatervapor
Liquidrefluxfrompumparounds
Noreboiler Strippingsteammaybeused
Neededfordeepcuts(1100F) Commonproblem cokinginfiredheater&washzone Firedheater highlinearvelocitiestominimizecokeformation
Washzone sufficientwashoilflowtokeepthemiddleofthepackedbedwet
Feed Atmosphericresiduum Allvaporcomesfromtheheatedfeed Undervacuum(0.4psi) Separatehigherboilingmaterialsatlowertemperatures
Minimizethermalcracking
Products Mayhavemultiplegasoils
UsuallyrecombineddownstreamtoFCCUafterhydrotreating
Vacuumresid Blended asphalt,heavyfueloil
Furtherprocessing thermal,solvent
o Choicedependsonproducts&typesofcrude
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VacuumDistillationSummary
DrySystem 1050F+cuttemperature&nostrippingsteam
Smallertowerdiameters Reducedsourwaterproduction Pressureprofile Flashzone:2025mmHgabs&750to770F.
Topoftower:10mmHgabs DeepCutSystem
1100F+cuttemperature&strippingsteam
Steamreduceshydrocarbonpartialpressures
Pressureprofile Flashzone:30mmHgabs HCpartialpressure1015mmHgabs Topoftower:15mmHgabs
SteamEjectors&VacuumPumps Vacuummaintainedontoweroverhead Steamsystemsconsideredmorereliable Wastesteamissour&mustbetreated Combinationssystems Laststeamstagereplacedwithavacuumpump
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Drawingfromhttp://www.enotes.com/topic/Injector
CrudeDistillationUnitCosts
Atmosphericcolumnincludes
Sidecutswithstrippers Allbatterylimitsprocessfacilities Heatexchangetocoolproductstoambienttemperature Centralcontrolsystem
Vacuumcolumnincludes
Facilitiesforsinglevacuumgasoil 3stagevacuumjetsystemat30 40mmHg HeatexchangetocoolVGOtoambienttemperature
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Topics
CrudeStills Historicallytheoldestrefiningprocess Onlythefirststepincrudeoilprocessing
Purpose Torecoverlightmaterials Fractionateintosharplightfractions
ConfigurationMaybeasmanyasthreecolumnsinseries CrudeStabilizer/Preflash Column
ReducetrafficintheAtmosphericColumn
AtmosphericColumn VacuumColumn
Reducedpressuretokeeptemperaturesbelow650F ProductYieldCurves CutPoint,Overlap,&Tails
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TypicalCutPointDefinitions
Cut TBPIBP(F) TBPEP(F)LightNaphtha(LSRGasoline) 80to90 180to220
HeavyNaphtha 180to220 330to380
MiddleDistillate(Kerosene) 330to380 420to520
AGO(AtmGasOil) 420to520 650
LVGO(LightVacGasOil) 650 800
HVGO(HeavyVacGasOil) 800 950to1100
VacuumResid 950to1100
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ProductYieldCurves CutPoint,Overlap,&Tails
Industrialdistillationcolumnsdonotprovideperfectlysharpseparations Initialcalculationsusingcrudeoilassaysassumethatallmaterialsatacertainboilingpointgoestooneproductoranother
Imperfectseparationsresultinlightends&heavyendstailsinadjacentproducts Presenceoftailscomplicatethedefinitionofcutpoint
Analysis Scaledistillationcurvestorepresentthevolumeremoved CutpointtemperaturerepresentsthefeedsTBPcorrespondingthecumulativevolumeremoved
Tailrepresentsthelightfractionsamountabovethecutpoint&theheavyfractionsamountbelowthecutpoint
Overlaprepresentstherangebetweenlightfractionsendpoint&theheavyfractionsinitialpoint
Endpointmayberepresentedby99%
Initialpointmayberepresentedby1%
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Example AtmosphericTowerProducts
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ScaletoFractionofCrudeCharge
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CutPoint,Overlap,&Tails
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Ref:R.N.Watkins,PetroleumRefineryDistillation,2nd ed.,1979
CutPoints&OverlapsforExample
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BoilingPointRangesforExample
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Summary
Reportedrefinerycapacitytiedtochargetocrudedistillationcomplex IncreasecapacitywithPreflashcolumn
Complexcolumnconfigurations Noreboilers,heatfromfeedfurnaces
Reuseheatviaheatexchangebetweenfeed&internalcolumnstreams Sidedraws,pumparounds,sidestrippers
Pumparounds required toensureliquidrefluxwithinthecolumn Strippingsteam 3phasecondensers
Condensedwaterwillhavehydrocarbons&dissolvedacidgases Preheattrainrecyclesheat
Products&internalstreamsheatthefeed Feedcoolstheinternalstreams&products
Vacuumcolumntoincreasetheeffectivecutpoints Vacuumcolumnslargediametertokeepvaporvelocitieslow Vacuumgasoilsrecombined onlyseparatedforoperatingconsiderations
Pressuredropsareimportant,especially inthevacuumcolumn Steamstrippingaidsinseparationwithoutcracking Metalsareundesirable.Canremovesome metalsviadesalters.
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Topics
CrudeStills Historicallytheoldestrefiningprocess Onlythefirststepincrudeoilprocessing
Purpose Torecoverlightmaterials Fractionateintosharplightfractions
ConfigurationMaybeasmanyasthreecolumnsinseries CrudeStabilizer/Preflash Column
ReducetrafficintheAtmosphericColumn
AtmosphericColumn VacuumColumn
Reducedpressuretokeeptemperaturesbelow650F ProductYieldCurves CutPoint,Overlap,&Tails
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SupplementalSlides
Phillips66capacities
Crudedistillationtechnologyproviders
Typicaldistillationcolumnconfiguration
Fractionationcolumns&trays
Fractionationtraytypes
Trays&packing
Typicaltrayefficiencies
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Phillips66DistillationComplexes
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U.S.informationfromEIA,Jan.1,2014database,publishedJune2014http://www.eia.gov/petroleum/refinerycapacity/
CrudeDistillationTechnologies
Provider FeaturesFoster WheelerShell Global SolutionsTECHNIPUhde GmbH Vaccum distillation
Complex of atmospheric & vacuum distilation for initial separation of crude oil. May include preflash column.
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TypicalDistillationColumn Topofcolumn condensertoremoveheat
Providesliquidrefluxthroughtopofcolumn Partialcondensermayhavevaporbutnoliquiddistallate product
Coldesttemperature coolingmediamustbeevencolder Lowestpressure Topsectionstripsheavycomponentsfromtherisingvapors
Feed
Vapor,liquid,orintermediatequality Introducedinvaporspacebetweentrays
Internals
Traystocontactrisingvaporswithfallingliquids Pressuredropacrosstrays overcomestaticheadofliquidontray,
Bottomofcolumn reboiler toaddheat
Providesvaportrafficinbottomofcolumn Highesttemperature heatingmediamustbeevenhotter Highestpressure Bottomsectionstripslightcomponentsfromthefallingliquid
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DrawingbyHenryPadleckas &modifed byMiltonBeychok:http://en.wikipedia.org/wiki/File:Continuous_Binary_Fractional_Distillation.PNG
FractionationColumns&Trays
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DrawingsbyHenryPadleckashttp://en.wikipedia.org/wiki/Fractionating_column
FractionationTrayTypes
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http://www.termoconsult.com/empresas/acs/fractionation_trays.htm
Trays&Packing
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http://www.ec21.com/product-details/Tower-Internals--3942077.html
TypicalOverallEfficienciesColumnService
TypicalNo.ofActualTrays
TypicalOverallEfficiency
TypicalNo.ofTheoretical
TraysSimpleAbsorber/Stripper 2030 2030SteamSideStripper 57 2ReboiledSideStripper 710 34ReboiledAbsorber 2040 4050Deethanizer 2535 6575Depropanizer 3540 7080Debutanizer 3845 8590AlkyDeiC4(reflux) 7590 8590AlkyDeiC4(noreflux) 5570 5565NaphthaSplitter 2535 7075C2Splitter 110130 95100C3Splitter 200250 95100C4Splitter 7080 8590AmineContactor 2024 45AmineStripper 2024 4555 912CrudeDistillation 3550 5060 2030StrippingZone 57 30 2
FlashZone1stdraw 37 30 12
1stDraw2ndDraw 710 4550 35
2ndDraw3rdDraw 710 5055 35TopDrawReflux 1012 6070 68VacuumColumn(G.O.Operation)Stripping 24 1FlashZoneHGODraw 23 12HGOSection 35 2LGOSection 35 2FCCMainFractionator 2435 5060 1317QuenchZone 57 2QuenchHGODraw 35 23HGOLCGO 68 35LCGOTop 710 57
Viscosity MaxwellDrickamer&BradfordinLudwig
cPAveViscosityofliquidonplates
MolalAveViscosityof
Feed0.05 980.10 104 790.15 86 700.20 76 600.30 63 500.40 56 420.50 50 360.60 46 310.70 43 270.80 40 230.90 38 191.00 36 171.50 30 71.70 28 5
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RefineryProcessModelingGeraldKaes,AthensPrintingCompany,2000,pg.32
RulesofThumbforChemicalEngineers,4thed.CarlBranan,GulfProfessionalPublishing,2005
EngineeringDataBook,12thed.GasProcessorsAssociation,2004
