HOT HYDROGEN ATTACK INspECTIONs - pasa.com.br por higrogênio.pdf · - Testing level 3 EN473, ASNT...
Transcript of HOT HYDROGEN ATTACK INspECTIONs - pasa.com.br por higrogênio.pdf · - Testing level 3 EN473, ASNT...
MISTRAS Group BV
Hofweg 153208 LE Spijkenisse
T: +31 (0)10 245 03 25F: +31 (0)10 245 03 26
E-Mail: [email protected]
Norbert TrimbornM: +31 (0)6 5278 0874
www.mistras.nl www.mistrasgroup.com
HOT HYDROGENATTACK
INspECTIONs
ExpERIENcE & REFERENcES
WWW.MISTRAS.NL
cONTAcT
Norbert Trimborn
• StudiesofAppliedPhysicsandNDT
• CertifiedinUltrasonic:
-Testinglevel3EN473,ASNTUTLIII,TOFDLIII,PALIII
• SpecialistadvancedNDT:
-TimeofFlightDiffraction(ToFD),PhasedArray(PA),
UltrasonicTesting(UT),GuidedWave(GW),Hot
HydrogenAttack(HTHA),HIC,PipeSupportInspection
• ExperienceindetectionandquantifyingofHTHAoverthe
past25years
TheinspectionmethodologydevelopedbyMistrasgivesan
absoluteindicationofthepresenceofHTHAinparentmaterial,as
longitisabovethe(lowandsafe)detectionthreshold.Decisions
canbemadeimmediately,thereisnoriskofanambiguousresult.
Ifnecessaryinordertomeasuretheprogressofattack,theinspec-
tionmethodologygeneratesdatathatcanbemonitoredveryaccu-
rately,on-line,andattemperaturesofupto450degreeCelsius.
Theinspectionmethodologyusesadvancedtechniquesincluding
TimeOfFlightDiffraction(TOFD),ultrasonicBackscatter,and
velocityratiomeasurements.Thisinspectionmethodologymeets
theHTHAinspectionapproachproposedinAPI941.
Backscatter Technique• Fastscreeningtechniqueforlargeareasthatgivesan
indicationofthepresenceofHTHA
• Note:WillnotdetectHTHAif100%ofthewallthickness
isattacked
Velocity Ratio Technique• Discriminatesbetweenindicationsresultingfrominclusions
frommanufacturing,andindicationsduetoHTHAmicro-cracks
filledwithCH4(Methane)
• Discriminates,between0%and100%attack
• Measuresextentofattack,between0%and100%ofwall
thickness
• Pointmeasurementsarecarriedout
ThepresenceofHydrogeninindustrialplantsisasourceofdamage.
HTHAisonesuchformofdegradationwhichisduetotheformation
ofMethane(CH4)byreactionwithcarboninsteel.HTHAcanoccur
eitherintheparentmaterialorinthewelditselfandmanifestsitselfin
severaltypesofalloys.
TheprobabilityofHTHAdamageinplantisdependentonthepartial
hydrogenpressure,operatingtemperature,andalloy.Methaneformed
bythereactionaccumulatesatinternalvoidsonthegrainboundaries,
whereundercertainconditionsthebuild-upcanproducemicro-cracks.
Intheweldmaterialthisleadsmostlytoaleakbeforebreaksituation
butwhenthedamageisintheparentmaterial,theresultismostly
catastrophicforpeopleandtheenvironment.
Advantages:
• SignificantreductionofriskresultsfromusingtheMistras
inspectionmethodology
• Actionscanbetakenimmediately,astheoriginof
indicationsareclassifiedwithextremelyhighreliability
• Attackcanbedetectedatanearlystagewhentheassethas
alongremaininglifetime
• Theprogressofattackcanbemonitoredaccurately
• Examinationisnon-intrusive,resultinginmajorcostsavings
• Theinspectionmethodologyisbasedonmorethan25years
oftraceableexperience.Todatenoincorrectassessments
havebeenmade
conclusions:
• TheMistrasinspectionapproachisbasedonmorethan25
yearsofexperience
• TheMistrasinspectionapproachhasbeenproventobe
reliableandreproducible
• Clearunambiguouspresentationofresults
• Allgeometriescanbeinspected
• Inspectionconformswithprocedures,usingtrainedand
certifiedOperators
HOT HydROGEN ATTAck (HTHA) ABSOLuTE dETEcTION & MONITORING AdVANTAGES & cONcLuSIONS