remote digital video inspection case studies case studies.pdf · a 10mw gas turbine was inspected...

Asset Longevity / Plant & Pipeline Performancewww.QuestIntegrity.com I [email protected]

Remote Digital Video Inspection case studies

• WaterTubeBoilers• HRSGBoilers• CondensateReturnSystems• PressureVessels• Tanks• PressurePiping• HeatExchangers• FinFans• GasTurbines

• SteamTurbines• Engines• Generators• Headers• SeaWaterCasions/Pumps• Aircraft• BacterialTrackandTrace• QAandQC• CIPEvaluation

• Transformers• AirHeaters• ElectricMotors• DebrisRetrieval• SteamTransportSystems• Tankers• Silos/Tanks/Cyclones• CoolingWaterSystems

RDVITM Case Studies

Water Tube Boiler

Duringawatertubeboilerinspection,largeamountsofdepositionwerefoundtobepresentthroughouttheunit.Fortunatelythisdepositionwasdetectedbeforeseriouscorrosionanddegradationhadoccurred.Therisksofhighdepositionlevelstoassetreliability,efficiency,emissionlevelsandlife-spanwerediscussedwiththeclient.Thisinformationpromptedmodifiedboileroperationandenhancementstothewatertreatmentprogramme.

Thiswatertubeboiler,alongwithotheroperationalunits,wasscheduledforannualRDVIinspectionsaspartoftheplantmaintenanceandinspectionschedule.Overthenextthreeyearsthedepositionwasremoved,resultinginnolong-termdamage.Thisprocesswascompletedwithouttheapplicationofexpensivechemicalcleaning.

Afterthreeyearstheclientreportedincreasedperformancealongwithreducedemissionsandenergycosts,andnocostsassociatedwithexpensiverepairs.TheyattributedtheirsuccesstoearlydetectionthroughtargetedQuestIntegrityRDVIwhichgavethemtheopportunitytomakeamendmentstotheiroperationalproceduresandimplementsimplesolutions,mitigatingtheriskofprematuretubefailures,subsequentrepairsandproductionlosses.


HRSG Boilers

AninspectionofanHRSGwasteheatboilerrevealedheavydepositionbuildup,flowassistedcorrosionandareasofisolatedcorrosion.Noindicationsofwaterorsteambornematerialhadpreviouslybeendetectedinthewatertreatmenttesting.Duetotheextentoftheflowassistedcorrosionandisolatedcorrosion,manytubeswererequiredtobereplaced.HRSGboilersareofa“cutyourwayinandweldyourwayout”constructionmakingthemexpensivetorepair.

Withtheresultsoftheinspectionhighlightingthedepositionandcorrosion,theclientalteredtheflowratesandvelocitiesinsidetheunitandimplementedtighterwateroperationalparametersformakeupwaterandcondensatereturntosuittheuniquecharacteristicsoftheirHRSGunits.

Condensate Return Systems

Theinspectionofacondensatereturnsystemthatwasfedfromsevendifferentplantsrevealedthepresenceoftwotypesofcorrosionandexcessivedepositionlevels.Chemicalsusedintherespectiveplantshadbeenenteringthecondensatesystemaswellasproductmaterial.Thisresultedinprematurereplacementofthecondensateline,whichrequiredsevenplantstoshutdownandcausedextensiveproductionlossesduringapeakproductionseason.

Regularinspectionofthislinepriortoleakdetectionwouldhavedetectedminorcorrosionandidentifiedthesourceoftheproblem,providingtheclientwithinformationtocompleteearlyremedialworkandextendingthesystem’slifeformanyyears.

Pressure Vessels

AnonshorefacilityplannedashutdowntocarryoutanRDVIinspectionprogramme.Theprimaryissueswehadtoconsiderwerethelengthoftimerequiredtoinspectallvesselsandtheavailabilityofthemanpowerrequired.

TheQuestRDVIIn-SpecprogrammewasimplementedacrossallplantvesselsusingourRDVIspecificITPsandVAPs.Ourreviewwiththeclientrevealedthat95%ofthevesselswereabletobeinspectedforGVIandCVIpurposesanddidnotrequireaconfinedspaceentrytobeperformed.ForthosevesselsthatwereselectedfortheapplicationofRDVI,strategicallyselectedaccesspointswerechosentoensurekeytargetareascouldbeaccessedtoensuretheintegrityoftheinspection.Theseinspectionpointsrequiredminimalmechanicalintervention,scaffolding,cranesandriggers.Astherewerenoconfinedspaceentryelementsandsmalldiameteraccesspointswereused,areducedlevelofisolationswasrequiredwhichfurtherreducedthecosts,personnelinvolvedandtheHSEriskprofile.

Theresultwasashutdowndurationreducedby51%alongwith85%reductionofassociatedcosts.TheresultsfromtheRDVIinspectionswereusedtoformpartoftheclient’songoingRBIrequirementsandstrategyforallfutureshutdownsforbothonshoreandoffshore.


Tanks

Alargehydrocarbonstoragetankrequiredinspection.Thereweretwomainchallengeswiththistank:• ithadamethaneatmosphereandcouldnotbeshutdownforinspection, • theonlysuitableaccesspointavailable(6inches)wasintheuppercentreof thetank.

Wecustombuiltalargecameraunitwithhighintensitylightstoenableuseoftheavailableaccesspointandclearlyidentifyalltheareasthatrequiredinspection.Aprocedurewasdevelopedtoenablenon-ISelectricalequipmenttooperateinahydrocarbonatmosphere.

Theinspectionwascompletedsafely,quicklyandwithoutanydisruptiontotheclient’sproductionschedule.AllrelevantinformationwasobtainedandtheclientwasableintegratethetankinspectionprocedureintohisRBIsystemsothatfutureinspectionscouldbecompletedwiththesamehighlevelofaccuracy.

Pressure Piping

Aseriesofhighpressurepipingsystemswereinspectedfromawellheadthroughandbeyondaprocessplant.Aseriesofcamerasystemswereusedtoensureaccurateresults.Approximately95%oftheentireprocesspipingwascoveredfromstrategicallylocatedaccesspoints.

Theclientcommentedthatthehighlevelofcoverageandsubsequentresultsprovidedthemwithahighlevelofconfidenceregardingtheconditionoftheplant,andputtingitbackintoservice.TheseresultsenabledtheclienttobettertargetotherNDTtechniquestospecificareaswhereindicationsorcorrosion/erosionhadbeennotedsothatfutureremedialworkcouldbescheduled.

TheresultsfromthisinspectionfurtherassistedtheirRBIprogrammingandallowedforextendedsurveyperiods.Theclientalsocommentedthatthecostpermetretoinspect,whencomparedtootherNDTtechniquescoveringthesamearea,providedexceptionalsavings.

Heat Exchangers

AseriesofshellandtubeheatexchangerswereinspectedusingRDVItechniques.

Tube side–RDVIinspectiondeterminedthatallexceptoneoftheunitswerefreefromdepositsandotherissuesrelatingtotheintegrityandefficiencyofthetubebundle.Fortheonetubebundlethatrequiredfurthercleaning,theheadwasremoved,thetubescleanedandre-inspectedtoascertaintheeffectivenessoftheclean,andtheheadre-instated.

Shell side–RDVIinspectiondeterminedtheinternalconditionofthevesselandtubebundlewithoutremovalofthebundle.

Asnoneoftheworkassociatedwithremovalofthetubebundleswasrequired,theclientsavedvaluabletime,resourcesandmoneyinascheduledoutagewithanextremelyshortduration.


Fin Fans

RDVItechniqueswereutilisedtoinspectaseriesoffinfanunitsthatcontainedvaryinglevelsofdeposition.TheseunitswerethencleanedandanIRISinspectionwasperformedwhichdetectedsomelargepittinginsomeareas.Theclientrequestedwere-inspectthecleanedtubesusingRDVI.OurinspectionoftheareasofpittingindicatedbytheIRIStestsfoundsomedepositionremainingandnopitting.FurthercleaningandRDVIwasundertaken.WewereabletopositivelyprovethattherewasnopittinginthetubesandshowthattheIRISwasunabletodifferentiatedepositionandpitting.

Thissavedtheclientthecostofre-tubingasetoffinfansunnecessarily.TheRVDIinspectionwasmoretime-efficientandhadahigherlevelofaccuracyindetectingdepositsthatarecommonlyfoundintheseunits.Thisinspectionshowedthatpreviouscleaningwasnotuptostandard,revealingthatfurthercleaningwasrequiredtoreachoptimumefficiency.

Gas Turbines

A10Mwgasturbinewasinspectedfollowingourgasturbineinspectionprocedures.Thesecondstagebladesinthehotsectionwerefoundtobeseverelydamaged.Thedamagewasconsistentwithheat/flamedamage,howeverthiswouldnottypicallyoccurinthisareaofagasturbine.

Discussionswiththeclientrevealedthattheunithadbeenrunonamixtureofgasfuelandliquidfuelforaperiodoftime.Thisexplainedthelongerthandesignedflamepathandtheexcessiveheatinthesecondstagearea.

Theturbinewasstrippeddownandthedamagedbladesandnozzlesreplaced.Aswewereabletoidentifytherootcauseoftheproblem,theclientwasabletomodifyhisgasfeedsystemtopreventliquidsfrombeingburnedinaturbinethatwasnotdesignedforliquidfuels.

Steam Turbines

Aclientwitha25Mwsteamturbinehadnoticeddecreasedperformanceandsuspectedtherewassomefoulingoftheblades.Productionconstraintsandsupplycontractspresentedsignificantchallengesregardingoff-linetime.Thetypicalcool-downperiodrequiredforournormalRVDIinspectionwasnotdesirable.

Theturbinewasinspectedusingourumbilicalheatexchanger(coolingjacket).Theunitwasstillreading240°Celsiusatthetimeoftheinspection.WedetectedfoulingontheLPsideoftheStage2bladesalongwithindicationsofdepositionpassingthroughtheHPglandsealsystem.Thiscontinuedbuildupofthesedepositsandtheprematureweartheycreateonglandsealsystemswouldhaveresultedinfurtherdecreasedperformanceandmoreextensiverepairs.Earlydetectionprovedtobeinvaluabletotheclient.

Thisinspectionenabledtheclienttoplananoutageatamoreappropriatetimeinordertoreplacethebladesandrepairtheglandsealsystem.Thesourceofthefoulingwasalsotracedandtherootcauseoftheproblemsolved.Thisunitwasonlyoff-lineforapproximatelyeighthoursasopposedtothenormal48hoursplus.


Engines

Whileon-siteduringascheduledinspectionoutage,aclientaskedustoinspectagasfiredV12enginethatdrovealargecompressor.

Theinspectionrevealedearlyindicationsoftheexhaustvalveseatburning.Thisinformationpromptedtheclienttoinstigatereplacementvalvesimmediatelyandbettertunetheair/fuelratiotopreventfurtherdamagetoothercylinderheads.Theclientwasdelightedthatthefindingshadsavedtheneedforafullheadreconditioning.

Traditionalcompressiontestingwouldnothavedetectedtheseearlyindicationsandwouldonlyhavedetectedtheissuewiththevalve,uponfailure.OurRDVIproceduredetectedthispriortofailure,savingmoneyandtime.TheseenginesarenowinspectedattheregularservicescheduleusingRDVIandsubsequentheadreconditioninghasbeenfullyeliminatedoutsideofenginerebuildschedules.

Generators

Inspectionofageneratorusedinthegeothermalindustryrevealedaparticulartypeofcorrosionassociatedwithhydrogensulphide.Earlydetectionenabledtheclienttoinstallfilter/scrubbersystemsonthegenerator’scoolingducts.Aswewereabletofullyascertaintheextentofthecorrosion,theclientalsoorganisedareplacementunittobebuiltandinstalledatalaterdate.

Withearlydetectiontheclientwassparedthecostsofproductlosses.Theinspectionforthistypeofgeneratortypicallytakesaboutthreehourswhichminimisesthetimetheunitisrequiredtobeoffline.Theclientelectedtomonitorthegeneratorandconductbi-annualinspections.

Headers

Inspectionofasteamheaderwithmultipletubepenetrationsdetectedaligamenttypecrackingbetweenthetubepenetrations.Theapproximatelengthanddepthofthecracksweredeterminedandthisinformationsharedwithengineersandmetallurgists.Theplantwasputbackintoservicebutwithveryshortinspectionintervals.TheinspectionprocedurewaschangedfromanIn-Servicetypetoa“ConditionMonitoring”inspectiontominimisedowntimeandenablethelevelandrateofdegradationtobeascertainedmoreefficiently.

Theseheaderswerere-inspectedonaregularbasisusingacustommadecameratoolandourconditionmonitoringprocedure.Theinspectionswerecompletedefficientlywithminimaldisruptiontoproductionlevels.Thechangesinthecrackindicationsweremonitoredandcheckedagainstminimummateriallevels.Thisgavetheclienttimetoinstigatepermanentrepairorreplacementoftheheadersandcontinueproductionwithoutincurringsubstantialproductionlosses.


Sea Water Casions/Pumps

Theinspectionofaseawaterliftpumpanddischargecasionprovidedinformationonthefollowing:• theconditionoftheinternalprotectivecoating• theamountofbio-foulingoccurring• theconditionofcorrosioncontrolanodesinsidethecasionanddirectly belowtheinlet• anyissuesinsidethepumpregardingtheshaftsupports,bearings andimpellors.

Thisinspectionwascompletedwithminimaldisruptiontotheavailabilityofthepumpforprocessoperation,anddidnotcauseanylossofproduction.Fromtheinformationgatheredtheclientwasabletodeterminethatnoremedialactionwasrequired.TheinspectionprocedureandresultswerethenenteredintotheclientsRBIsystem.

Aircraft

Anaircraftwassetforascheduledinspection.Thisaircrafthadanumberofoperationalissuesassociatedwithitsworkingenvironment.Theverywindyairportwasadjacenttothesea,andthecraftdidhighaltitudeworkadjacenttoaskifield.

Uponinspectionwenoteddegradationtotheenginefromsaltingestion.Theinformationgatheredfromthisinspectionplacedtheengineon50hourserviceintervalsuntiltheenginecouldbereplaced.Italsoresultedintheenginemanufacturerchangingthecoatingonthebladesinthehotsectionandthematerialusedinthecompressorsectionoftheenginetoonemoresuitedtotheaircraft’soperationalenvironment.Theclientwasabletocontinuetooperatehisaircraftwithminimaldisruptionuntilanewandmoresuitableenginearrivedfromthemanufacturer.

Bacterial Track and Trace

RDVImethodswereemployedtoinspectafoodprocessingfacilitywithhighAPCs,productcontaminationissues,higherCIPcostsandreducedplantavailabilityforproduction.

Twoissuesoccurringwithinthepipingsystemswereidentified.ThefirstwasineffectiveCIPperformanceinsomeisolatedareasofthesystemduetopipingdesign/installation.Thesecondwasaseriesofweldstructureswithdefectsthatharbouredbacteriawhichwerenotabletoberemovedduringthecleaningprocess.

Allthedefectiveweldsweretaggedforremovalandtheareasofpipingthatwerenotbeingcleanedeffectivelywerere-routed.Thisresultedinasignificant50%increaseinproductiontimesbeforeaCIPcyclewasrequired.Italsoreducedtheissuesassociatedwithproductqualityenablingtheclienttosellhisproductforhigherrates.


QA and QC

Aseriesofweldseamshadbeeninspectedbytorchandmirror,andradiographyinasterilefoodprocesssystem.Theclientwasconcernedwiththedisruptionofworkduringradiographyandthelimitationsofthetorchandmirrormethod.

TheSterileWeldingITPwasusedasittargetsthedefectsknowntocauseissueswithbacterialandqualitycontrol.AseriesofweldstructuresthatwouldharbourbacteriaandbeunabletobecleanedeffectivelyusingtraditionalCIPmethodswasidentified.RDVIwasabletoreachwellbeyondthetorchandmirrorlimitationsandidentifiedweldformationsthathadbeenpassedbyradiographybutwereactuallyformationsthatharbourbacteriaandcannotbeeffectivelycleaned.

Theclientconcludedthatourinspectionsweremoresuitablethanprevioustechniquestheyhademployed.RDVImethodsenabledaccesstoareasrequired,providedahighlevelofdefinition/accuracythatcouldnotbeachievedwithradiography,reduceddisruptiontimeandincreasedthecoverageperday.Thisresultedinsavingsof75%comparedwithpreviousmethods.Italsoensuredthattheiroperationalsystemcouldbemaintainedasasterileenvironmentasrequired.Resultsofthisinspectionwereusedtofurtherup-skilltheweldingcrewstoenableamoreconsistentdefectfreeweldingprocess.

CIP Evaluation

AclientrequestedRDVIinspectiontoprovideinformationontheeffectivenessofaCIPprocess,whichwascurrentlyexperiencingsomeissues.

TheinspectionrevealedthattheCIPprocesswasnoteffectivelycleaningthesystem.Productresidue,solidsandfatswerenotedinthesystemwithwhatappearedtobeabiofilmpresentin40%oftheprocesspiping.SectionsofthepipingwerereplacedandsomemodificationsweremadetotheCIPsystem.TheresultsoftheinspectionpinpointedtheexactlocationswheretheCIPprocesswasnotperformingcorrectlyandsubsequentmodificationsweremadetotheplant.

ThisenabledtheclienttoreducehiseffectiveCIPcycleandtargetaprocessthatwasmoreeffectiveforthetypeofproductbeingmanufactured.Italsoprovidedhimwithlongerproductiontimesandreducedeffluentdischarge,chemicalandenergyuse.Theproductqualitywasincreasedprovidingalongershelflife.

Transformers

AclientwantedtouseRDVItechniquesinanelectricaltransformertoseeifwecouldremoveaforeignobjectdroppedintheunit.Theobjectwassuccessfullylocatedandremoved.Furtherinspectionoftheunitrevealedseriousdegradationtotheinsulationandshowedthatmanyoftheinternalpackershadloosened,withsomefallingtothebottomoftheunit.

Theloadonthisunitwasloweredtopreventacatastrophicfailureandtheclientwasabletoplanandarrangeforareplacementunit.ThisinspectionshowedtheabilityofRDVItechniquestodetectproblemsthatcannotbedetectedwithtraditionaltesting.Asaresultoftheinspectionoutcome,theclientimplementedregularRDVIinspectionstoensurepreventionofprematurefailuresinsimilarunits.


Air Heaters

Aclient’sairheaterunitsforairdryingoperationswerecrackingcausingsteamandassociatedchemicalstocontaminatethefoodproductbeingprocessed.RDVIinspectionrevealedanumberofissueswiththemethodinwhichthetubepenetrationsweremountedintheheaderandthequalityofthewelds.

Asaresultoftheinspection,theentireairheaterwassettobereplacedandawarrantyclaimwaslodgedwiththemanufacturer.Theinspectioninformationwasalsousedinaredesignoftheunits.AllnewunitsforthisclientarenowinspectedbyusingRDVItechniquestoensurethatthejointtypeiscorrectandinternalweldprofileisuniformtopreventstresspoints,crackingandcorrosion.QuestIntegrityRDVIhavedevelopedaspecificITPfortheseunitsandasetofstandardsfortheinternalweldseamprofilethatisnowusedextensivelyintheseunits.

Electric Motors

RDVIwasusedtoinspectalargeelectricdrivemotorthathadgotwet.Theinspectionrevealedcoronawaspresentinandaroundthewindingsinthemotor.Theinspectionalsodetectedanumberofotherissuesassociatedwiththeconditionofthewindings,supports,insulationanddeposition.

Withtheresultsofthisinspectiontheclientwasabletoplanasuitabletimetocompletetherepairsandreorganiseplantoperationtoreducetheloadsonthemotor.Theclientrequestedourinspectionprogrammetobeimplementedacrossalltheirelectricmotorsaspartoftheirmaintenanceschedule.

Debris Retrieval

Aclientsuspectedthataseriesofrecentplanttripsmaybeassociatedwithaparticularpressurevessel.RDVIwaschosenearlyoninthefaultfindingprocesstohelpdeterminethecause.

Themosttime-efficientmethodofinspectionwasrequestedastheplantwouldbedowninacriticalproductionarea.Theinspectionrevealeddebrisblockingthedischargenozzleinthebottomofthevessel.Theclientwasconcernedthataconfinedspaceentrywasrequiredtoremovethedebris.Aconfinedspaceentrywouldrequirefurtherisolation,ventingandpurgingandwouldcausefurtherdelaysingettingtheplantrestarted.

UsingourspecialistRDVIretrievaltools,wewereabletoremoveallthedebriscausingtheobstruction,eliminatingtheneedforaconfinedspaceentry.Thevesselwasclosedupandplantrestartedimmediately.Thisisatechniquewedeployregularlytoremoveforeigndebrisfromprocessplantandalsowithsteamturbinecleanoutandre-assemblyprocedures.


Steam Transport Systems

Amainsteamfeedlineconnectedtoeightdifferentprocessplantswasinspected.Inspectionrevealedisolatedareasofcorrosioninthesteamlines.Theclientwasabletoinvestigateanddeterminethattherootcauseofthecorrosionwasachemicalusedinthesteamgenerationprocess.Achemicalsubstitutewasfoundandused.

TheclientwasabletotargetotherNDTtechniquesinareaswherewenotedcorrosiontoascertainminimumwallthicknesslevelsandcompleteremedialworkasnecessary.

Tankers

AnRDVIinspectionofmilktankerbodiesrevealedtwomajorissuesaffectinganumberoftankerbodies–aparticulartypeofsprayballwasnoteffectivelycleaningthetankers,andtherewaslooseinternalpipingbeginningtodamagetheinternalsurfacesofthetanker.

Theclientwasabletotemporarilyremovethesetankerbodiesfromservicewhilstkeepingthosewithcorrectsprayballsystemsandpipefasteningsinservice.Theloosepipingwasabletoberepairedeasilyasearlydetectiondidnotallowforextensivedamagetooccur.

Thisinspectiondidnotdisruptthescheduledmilkpickupswhichwouldhavebeenthecaseifeachunithadbeeninspectedusingaconfinedspaceentrymethod.

Silos/Tanks/Cyclones

Aseriesofbalancetanks,silosandcycloneswereinspectedaspartofanannualsurvey.Wewereabletodeterminethatanumberofunitswerenotcleaningcorrectly.Comparisonoftheseresultswiththeresultsfrompreviousinspectionsrevealedthatseveralunitsweredevelopinga“bloom”.

TheclientwasabletoreplacedefectivesprayballsandmodifytheCIPprocesstoensuretheunitwascleanedtoamoresatisfactorystandard.Theywerealsoabletoproduceproductwithamoreconsistentqualityandeliminatecostlyproductdowngrades.

Cooling Water Systems

Acoolingwaterjacketsysteminasteelrollingmillwasinspected.Alargeamountofdeposition,tuberculationandindicationsofunder-depositcorrosionwerefoundinthesystem.Thiswasreportedtotheclientwhodismissedtheinitialfindingsandourdraftreport.Wereturnedtoourofficeandcompiledthefinishedreportwithanextractfromtechnicaljournalsonthetypeofcorrosionandformationswehadnoted.Theclientreadourfinishedreportandbegantoarrangefortheentiresystemtobere-built.

Theclientconfirmedthattheinformationwehadprovidedattheendoftheinspectionwastrueandcorrect.Healsostatedthatiftheinspectionshadbeenundertakenearlier,theinitialindicationswouldhavebeenidentifiedand,throughalteringoperationalprocesses,preventedtheprematuredegradationandreplacementofthesystem.

QUEST INTEGRITY GROUP

We are a global leader in the development and delivery of asset integrity and reliability management services and solutions for our clients. Our solutions consist of technology-enabled, advanced inspection and engineering assessment services and products that help companies in the refining and chemical, pipeline, syngas and power industries reduce operational and safety risks, improve operational planning and increase profitability. Quest Integrity Group, a Team Industrial Services company, is built on a foundation of leading edge science and technology that has innovated and shaped industries for over forty years.

www.QuestIntegrity.com

remote digital video inspection case studies case studies.pdf · a 10mw gas turbine was inspected...

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