8MOLY-BLOWDOWN-598

NOTE:ThisisforTrainingonly,andisnotintendedtobeusedasastepbystepprocedure.PO/MTBEMOLYBLOWDOWNSYSTEMNOTE:ThisisforTrainingonly,andisnotintendedtobeusedasastepbystepprocedure.PO/MTBEMOLYBLOWDOWNSYSTEMGENERALDESCRIPTIONPurposeThepurposeoftheMolybdenumBlowdownSystemistoprovidealocationwherevesselscontainingEpoxidationCatalystSolutionor4%Molycanbecollectedinaclosedmolyblowdownsystem.Itprovidesalocationwherethecatalystcanbecontainedandkeptoutofthenormalblowdownsystembecausemolybdenumcomplexsolidifiesandcancausecorrosionandfoulingproblemsintheboilersandflaretips.ThevesselsandequipmentassociatedwiththemolybdenumcontainingepoxidationcatalystsolutionareemptiedintoCatalystSolutionBlowdownPot.Nitrogenblendswiththesolutioninthisdrum.Whenthepressureonthisdrumexceeds0.055MPag,thevaporinthedrumgoestothelowpressureventgasheader.Ifthepressureinthedrumexceeds0.60MPag,thepressurereliefvalve(PSV)releasesthevaportothehighpressureflare.MOLYBLOWDOWNSYSTEMNOTE:ThisisforTrainingonly,andisnotintendedtobeusedasastepbystepprocedure.PO/MTBEThecontentsoftheblowdownpotarepumpedtotheCatalystRecoveryDrum.SomeofthemolybdenumcontainingepoxidationcatalystsolutionvesselsandequipmentblowdowndirectlytotheCatalystRecoveryDrumanddonotgothroughtheCatalystSolutionBlowdownPot.TheCatalystRecoveryDrumcontentscanthenbepumpedandrecoveredintheResidueEvaporatorFlashDrumandsenttotankageasCatalystResidue.MOLYBLOWDOWNSYSTEMNOTE:ThisisforTrainingonly,andisnotintendedtobeusedasastepbystepprocedure.PO/MTBEThefollowingvesselsandequipmentareallconnectedtotheMolybdenumBlowdownSystem:•TBARemovalColumnbottoms•TBARemovalColumnBottomsPumps•TBARemovalReboiler•CatalystRecycleFilter•CatalystRecycleSurgeDrum•TBARecoveryColumnbottoms•TBARecoveryReboiler•TBARecoveryBottomsPump•ResidueEvaporatorFlashDrum•ResidueEvaporatorExchanger•ResidueEvaporatorExchanger•MoBottomsPump•CatalystPreparationReactor•CatalystSolutionTransferPumpMOLYBLOWDOWNSYSTEMNOTE:ThisisforTrainingonly,andisnotintendedtobeusedasastepbystepprocedure.PO/MTBE•CatalystSolutionFilter•CatalystSolutionTanks•CatalystRecyclePump•CatalystSolutionMeterPump•CatalystSolutionPolishingFilter•CatalystSolutionBlowdownPot•CatalystSolutionBlowdownPump•CatalystRecoveryDrum•CatalystRecoveryPumpMOLYBLOWDOWNSYSTEMNOTE:ThisisforTrainingonly,andisnotintendedtobeusedasastepbystepprocedure.PO/MTBEMOLYBLOWDOWNSYSTEMSTARTUPGUIDELINEThisprocedureisperformedunderthefollowingconditions:•ReturningMolybdenumBlowdownSystemtoservicefollowingmaintenancerepairsafterT&I•NitrogenpurgingMolybdenumBlowdownSystemandlinestodisplaceoxygenorairthatmayhaveenteredsystem•Priortocompleteunitstartup.•Allbleedersanddrainvalvesareclosed.•EnsureallvalvesconnectedtoMolybdenumBlowdownSystemfromvesselsandsystemsareblockedin.•Ensureall25mmby-passvalvesaroundfloworificesareopentoallownitrogenpurging.NOTE:ThisisforTrainingonly,andisnotintendedtobeusedasastepbystepprocedure.PO/MTBEEnsurethefollowingvalvesareclosed:•N7nitrogenatrootvalvesconnectedtoblowdownheader•50mmvalveonmolybdenumblowdownheadertoCatalystSolutionBlowdownPotlocatedontopofpot•80mmvalveonmolybdenumblowdownheadertoCatalystRecoveryDrumlocatedontopofdrum.•ConnectnitrogenhosestobleedervalvesdownstreamoffloworificesonN7nitrogenpurgelines.Ensurethefollowingvalvesareclosed:•N7nitrogenatrootvalvesconnectedtoblowdownheader•50mmvalveonmolybdenumblowdownheadertoCatalystSolutionBlowdownPotlocatedontopofpot•80mmvalveonmolybdenumblowdownheadertoCatalystRecoveryDrumlocatedontopofdrum.•ConnectnitrogenhosestobleedervalvesdownstreamoffloworificesonN7nitrogenpurgelines.MOLYBLOWDOWNSYSTEMNOTE:ThisisforTrainingonly,andisnotintendedtobeusedasastepbystepprocedure.PO/MTBE•OpennitrogensupplyvalvestoallowpurgeofMolybdenumBlowdownSystem.•Openbleedervalvesonheadertoallownitrogenpurgeofheader.•Purgeheadersforaminimumof1hour.Openblockvalvesonmolybdenumblowdownheadersystematthefollowinglocations:•ValvelocatedontopofCatalystSolutionBlowdownPot•ValvelocatedontopofCatalystRecoveryDrum.•OpenbleedervalvesonN7nitrogenpurgelinetodisplaceairinline.•Checkoxygencontentatopenbleederstodetermineairandoxygenhavebeendisplaced,oxygencontentreadingmustbe3%orless.MOLYBLOWDOWNSYSTEMNOTE:ThisisforTrainingonly,andisnotintendedtobeusedasastepbystepprocedure.PO/MTBE•Closeallbleedersopentoatmosphereonlineswhereoxygenreadingsweretakenduringnitrogenpurging.•PressureMolybdenumBlowdownSystemtoapproximately0.345MPagnitrogen.•Blockinnitrogenconnectedtoheaderonbleeders.•Checksystemfortightnessandleaksforapproximately1hour.•Blockin,DepressureandDisconnectnitrogenhosesfrombleedersonheaderandlinesthenstorehoses.•Slowlyopenbleedervalveonheadertodepressureheaderandlinestoatmosphere.•Closebleedervalveonheaderasnitrogendropstonear0MPagtopreventairfromre-enteringthesystem.•OpenupstreamanddownstreamvalvesaroundN7nitrogenpressurecontrollers.•MolybdenumBlowdownSystemisreadyforservice.MOLYBLOWDOWNSYSTEM