Teknologi Pemrosesan Gas (TKK 564) Instructor: Dr. · PDF fileTeknologi Pemrosesan Gas (TKK...
Transcript of Teknologi Pemrosesan Gas (TKK 564) Instructor: Dr. · PDF fileTeknologi Pemrosesan Gas (TKK...
Teknologi Pemrosesan Gas(TKK564)
Instructor:Dr.Istadi(http://tekim.undip.ac.id/staf/istadi )
il i di di idEmail:[email protected]
I t t B k dInstructorsBackground
BEng.(1995):Universitas DiponegoroMeng.(2000):Institut Teknologi BandungPhD.(2006):Universiti Teknologi Malaysia
Specialization:CatalystDesignforEnergyConversionP D i f E C iProcessDesignforEnergyConversionCombustionEngineeringComputationalFluidDynamic(CFD)ComputationalFluidDynamic(CFD)
CourseSyllabus:(Part1)CourseSyllabus:(Part1)y ( )y ( )1. DefinitionsofNaturalGas,GasReservoir,Gas
Drilling,andGasproduction(Pengertian gasalam,g p g ggasreservoir,gasdrilling,dan produksi gas)
2. OverviewofGasPlantProcessing(OverviewSistemPemrosesan Gas)Pemrosesan Gas)
3. GasFieldOperationsandInletReceiving(Operasi Lapangan Gasdan Penerimaan Inlet)
4. GasCompressionSystem (Sistem Kompresi Gas)5. GasTreating(Pengolahan Gas)
( )6. GasDehydration(DehidrasiGas)7. FirstAssignment8 Ujian TengahSemester8. Ujian TengahSemester
FIELDOPERATIONS:WellheadOperations
WellheadGasliquidseparatorInstrumentshedCondensateTankIfthegasisnonassociated,hydrocarbonliquidsknockedoutintheseparatormayberemixedintheseparatormayberemixedwiththegasorstoredinatankandremovedbytruck
FIELD OPERATIONS: PipingFIELDOPERATIONS:PipingOffshoreProduction:
M ll i db k l fManywellsaretiedbacktoplatformGasfrommultipleplatformsaretiedtogetherintolargepipelinethatgotothegasplant(usuallyonshore)
O h P d tiOnshoreProduction:FormanextensivenetworkofsmalllinesfromindividualwellsTieintoincreasinglylargerlinesTieintoincreasinglylargerlinesThesmallergatheringlinesmaybeabovegroundorburiedLargerlinesarealwaysburiedAb dli h i t i t i b t AbovegroundlinesaremucheasiertomaintainbutareexposedtotheatmosphereSurfacecoatingforcorrosionpreventionandpossiblyinsulationmayberequiredinsulationmayberequired
FIELDOPERATIONS:CompressionSt tiStations
Onshorecompressionstation boosterstationOnshorecompressionstation boosterstationBoosterstationsarerarelyusedinoffshoreproduction
inletsuctionseparators(scrubbers)toremoved d l dcondensedliquids
Dehydrationfacilities toreducecorrosionandmitigatehydrateformationmitigatehydrateformation.Whenrequired,chemicalinhibitorsforcorrosionandgashydratepreventionareinjectedintotheandgashydratepreventionareinjectedintothedischargedgas;meteringpumpsareusedtocontrolinjectionrates
Howtohandlecondensedliquidsatboosterstationsisaneconomic
decision ?decision?Liquidscollectionrequirestankage andtruckingtomovetheliquidstotheplant.q pThebenefitsarehigherlinecapacity,reducedcorrosionrates,andreducedchemicalhydrateandcorrosioninhibitorinjectionrates inhibitorinjectionrates.Piggingrequirementsarereduced,aswellasthepotentialforlargeliquidslugsenteringtheplant.P i li id b ki h i li li i h dPuttingliquidsbackintothepipelineeliminatestheneedfortanksandtruckingbutincreaseschemicalcosts,putsmoreimportanceongoodpigging,andprobablyincreases
lpipelinemaintenancecosts.
CompressorpowerrequirementsdependupongasflowandpressureratioBoosterstationhorsepowerrangesfromtheteenstothethousands.Compressorsaredrivenbyelectricmotors,internalcombustion
i d t bi engines,andgasturbines.Horsepowerrequirementsandavailabilityoffueldictatethebestchoice.Somecompressordriversareinternal combustionenginesthatSomecompressordriversareinternalcombustionenginesthathavebeeninservicefor50ormoreyearsandhavebeenrebuiltmanytimes.Compressorenginesareusuallyfueledwithnaturalgas.ThebestCompressorenginesareusuallyfueledwithnaturalgas.Thebestfuelissalesgasfromtheplantbecauseitiscleanandhasaconstantheatingvalue.However,thistypeoffuelingrequiresrunningpipebetweenthel db iplantandboosterstations.
FIELDOPERATIONS:PiggingO O S: gg gPigging istheprocessofforcingasolidobjectthroughapipeline.apipeline.Theprocessinvolvesinsertingthepig,viaapiglauncher,intothepipelinesandremovingitbyuseofapigreceiver.Pi i i d f f h f ll i f iPiggingisusedtoperformanyofthefollowingfunctions:
Provideabarrier betweenliquidproductsthatusethesamepipelineCheckwallthicknessandfinddamagedsectionsoflinesRemovedebrissuchasdirtandwaxfromlinesProvideaknownvolumeforcalibratingflowmetersProvideaknownvolumeforcalibratingflowmetersCoatinnerpipewallswithinhibitorsRemovecondensedhydrocarbonliquids andwaterintwophasepipelinesphasepipelines
Fieldoperationsmustfollowarigorouspiggingg gg gscheduletopreventtheplantfrombeinghitbylargeslugsofliquidthatwouldfloodinletreceivingandcarryliquidsintothegas processingunits carryliquidsintothegasprocessingunits.Fortunately,plantoperatorsusuallyknowwhenakillerpigiscoming,andtheydrawdownliquidkillerpig iscoming,andtheydrawdownliquidlevelsininletreceiving.Toprotecttheplantfromlargeliquidsurges,operatorsrespondbyshuttingingas,whichshutsdownfieldcompressorsandupsetstheplantwiththepotentialforproducingoff specproductsforproducingoffspecproducts.
Shapes of foam sphere and pigsShapesoffoamsphereandpigs
Foamspheres,likethoseshownintheleftfrontofFi l di th i li Figure3.5,aremorecommonlyusedingatheringlinesbecausemultiplespherescanbeloadedintoapiglauncherforremotelaunching.gThelauncherstypicallyholdthreetofivespheresandareinclinedsothatspherescanbeinsertedremotelybygravityfeedSpheresfornominal2to4inch(50to100mm)di t li lid h l diameterlinesaresolid,whereaslargeronesareinflated,usuallywithwaterorethyleneglycolwatermixtures.
Sphere launcher unitSpherelauncherunit
Attheendoftherun,thesphereiscaughtinasphereh ( ll ll d h f hcatcher(usuallycalledapigcatcherevenifspheresare
used).BothlaunchersandreceiversareonthestraightrunBothlaunchersandreceiversareonthestraightrunofapipetee.Pressuredifferentialdrivesthespherethroughtheli line.However,itusuallystopsintermittentlywhenitcomestolowpointswherepoolsofliquidaccumulatetolowpointswherepoolsofliquidaccumulate.Fieldandplantoperatorslearnthetypicalruntimesforspheresinaline,andinlinedetectorssignalah l isphereslocation.
GASHYDRATESPipelineblockageisusuallycausedby:
Waxandasphaltene solidsdeposition(lack)Waxandasphaltene solidsdeposition(lack)Scale(inorganicsalt)depositionGashydratesolidsformationy
First,hydrateplugscanoccurwithinminuteswithoutpriorwarning,whiletheothersolidstakeweeks,months oryearstocausepluggingandareusuallymonths,oryearstocausepluggingandareusuallydetectedbyincreasedlinepressuredrop.Second,althoughhydrateformationcanbeinhibitedg yinanumberofways,injectionpumpfailure,separatorfailure,andprocessupsetscansuddenlymakepipelinecontentsvulnerabletohydrateformation.contentsvulnerabletohydrateformation.
PropertiesofGasHydratesp y
Gashydratesareaclassofsolid nonstoichiometricGashydratesareaclassofsolid,nonstoichiometriccompoundscalledclathrates.Theyformwhenahostmaterial,waterforhydratesy , ythroughhydrogenbonding,formsacagedstructurethatcontainsguestmolecules,suchas
th methane.Bothhostandguestmustbepresentforthesolidtoform butnotallofthecageswillbeoccupied form,butnotallofthecageswillbeoccupied.Gashydratesshouldnotbeconfusedwithsalthydrates,whichformstoichiometric compounds.y , p
HYDRATE FORMATION PREDICTIONHYDRATEFORMATIONPREDICTIONThermodynamicsprovidesapowerfultoolforpredictionofthetemperatureandpressureforhydrateformationonthebasisofgascomposition.H d f i ki i i l d l Hydrateformationkineticsiscomplexandpoorlyunderstood,partlybecausethecrystalgrowthprocessisrandomisrandom
Forbelow1 000psi(70bar)Forbelow1,000psi(70bar),
ThespecificgravityisdefinedastheratioofthemassThespecificgravityisdefinedastheratioofthemassofagivenvolumeofagastothatofanequalvolumeofair;bothvolumesaremeasuredat14.7psia and60F( b d C) (1.01barand15.6C).Foranidealgas,thespecificgravityismolarmassofthegasdividedbythemolarmassofair(28 96)thegasdividedbythemolarmassofair(28.96).
ExampleGascomposition:
Estimatethehydrateformationtemperatureat325psia (22.4bar)fortheabovegascomposition?
Thespecificgravity=molarmassgas/molarmassair=20 08/28 96=0 69320.08/28.96=0.693.
t=16.56.83/(0.693)2+13.8 ln(325)=49F.
HYDRATE INHIBITIONHYDRATEINHIBITIONThreewaysexisttoavoidhydrateformationinnaturalgasy y gstreams:
Operateoutsidethehydrateformationregion.(impractical)( p )Dehydratethegas.Addhydrateinhibitor(themostcommonlyused)
Regardingdehydration howdryagasshouldbetopreventRegardingdehydration,howdryagasshouldbetopreventhydrateformationisuncertain.Thegasobviouslyshouldhaveawaterdewpointbelowthel i id d i lowestoperatingtemperaturetoavoidwatercondensation.Thermodynamicspredictsthathydratescanformevenwhenthegasphaseisunsaturatedwithwater.g p
Useofchemicalinhibitorsistheleastattractiveh d i hibi i h df lhydrateinhibitionmethodforseveralreasons:
Theproperinhibitordosagemustbeknowntoavoidpluggingorneedlesschemicalcosts,butoftentimesitisdeterminedempirically.Thechemicalcost,althoughitisusuallyasmallfractionofoveralloperatingcosts.Thereliabilityofinhibitorinjectioncanbeaproblembecauseofmalfunctioninginjectionpumpsanddepletedinhibitorreservoirs,especiallyatremotesites.Thepossibleinteractionbetweenhydrateinhibitorsandotheradditivesreducestheeffectivenessofsomeofadditives,aneffectthatisusuallydeterminedempirically.
ChemicalhydrateinhibitorsTypesy ypAntiagglomerates (AA) 1990sKi ti (KHI)Kinetic(KHI) 1990sThermodynamic
AntiagglomeratesAntiagglomeratesAntiagglomerates preventsmallhydrateparticlest agg o e ates p eve t s a yd ate pa t c esfromagglomeratingintolargersizestoproduceaplug.Theinhibitorsresideintheliquidhydrocarbonphaseandaremostoftenusedinpipelineswheregasisdissolvedinoil dissolvedinoil.Theyrequiretestingtoensureproperconcentrations.
KineticInhibitorset c b to s
Kineticinhibitorsslowcrystalfor