Cooling System Lay-Up Best Practices

BestPracticesVisitusonlineatwww.gewater.com©2004,GeneralElectricCompany.Allrightsreserved.AmericasMinnetonka,MN+1-952-933-2277Europe/MiddleEast/AfricaHeverlee,Belgium+32-16-40-20-00Asia/PacificShanghai,China+86-21-5298-4573GlobalHeadquartersTrevose,PA+1-215-355-3300CH0000EN0411*TrademarkofGeneralElectricCompany;mayberegisteredinoneormorecountries.Lay-UpofEquipmentinCoolingWaterSystemsBestPracticesforCoolingSystemandEquipmentLay-UpIntroductionProtectionofcoolingsystemsandrelatedequipmentshouldalwaysbeconsideredregardlessofitbeinginser-vice,comingoutofservice,idle,orinstorage.Improperlytreatedsystemsduringintermittentoperationorshutdownswillcreatecorrosionand/orfoulingproblemswhicharedifficulttoovercomeoncethesystemisbroughtbackon-line.Byfollowingsomebasicbestpracticesduringintermittentoperationordowntimebetterprotectionwillbeensured.Lay-uporstorageofcoolingsystemsorequipmentcanbeclassifiedasa“Dry”or“Wet”lay-up.Eachhasitsadvantagesanddisadvantages.Remembertoconductthepropersystemshutdownandstartupproceduresbeforeandaftereverylay-uporturn-a-round.Avoidhavingidleheatexchangerbundlesunprotectedanddon’tletimproperlytreatedequipmentsitstagnant.AspecialnoteforEnhancedTubedesign,itiswellknownthatenhancedsurfacetubeshaveinherentstressesfromthemanufacturingprocess.Theseareasofstressarepotentialcandidatesforlocalizedcorrosionattack.Thisdesign,withitsmanyridgesandcrevices,alsoactsasastrainerfordebrisandtendstocollectsuspendedmatter.Itisimportanttoavoidlowfloworstagnantconditionsandalsotominimizesuspendedmatterandhighironlevelsinthecirculatingwaterespeciallyifthistypeequipmentisbeingstored.Suspendedmaterialsinthecirculatingwaterwilltendtosettleonidleheatexchangesurfaces.Especiallywithenhancedsurfaceexchangers,thiscreatesasituationwhereunderdepositattackandmicrobiologicallyinfluencedcorrosion(MIC)canoccur.Thesematerials(organicandinorganic)willalsoimpactontheinhibitorsabilitytoprotectthesurfaces.Itisim-perativethatproperpre-cleaning,lay-up,andpassivationproceduresbeimplementedtomi