Vim li cas Duplex Stainless Steel Pipes yog qhov tseem ceeb rau Offshore Roj Rigs

Vim li cas Duplex Stainless Steel Pipes yog qhov tseem ceeb rau Offshore Roj Rigs

Cov roj av offshore yog ib qhov chaw ua phem tshaj plaws hauv ntiaj teb rau hlau. Dej hiav txwv. Ntsev- cua. Siab siab. Hloov qhov kub thiab txias. Hydrogen sulfide (H2S) hauv cov kua ua kua. Ib qho ntawm cov xwm txheej no tuaj yeem rhuav tshem cov yeeb nkab zoo tib yam hauv xyoo - qee lub hlis. Ua ke, lawv tsim ib puag ncig corrosion uas xav tau cov khoom siv tshwj xeeb.

Lub ntiaj teb no offshore roj thiab roj kev lag luam ua hauj lwm ntau tshaj 1,400 ruaj platforms thiab pua pua ntawm floating ntau lawm units thoob ntiaj teb. Cov kav dej - nqa cov kua dej, cov dej hauv hiav txwv, nqa roj, thiab cov khoom siv hluav taws xob - suav rau qhov tseem ceeb ntawm qhov hnyav tag nrho thiab cov nqi peev. Qhov tseem ceeb tshaj, ib qho kev ua tsis tiav ntawm cov kav dej tuaj yeem ua rau muaj kev lag luam kaw uas raug nqi $ 500,000 txog $ 1,000,000 toj ib hnub, kev nplua rau ib puag ncig, lossis qhov xwm txheej phem tshaj plaws, qhov xwm txheej nyab xeeb.

Qhov no yog qhov tseeb vim li cas duplex stainless hlau tau dhau los ua cov khoom ntawm kev xaiv rau offshore piping engineers. Tsis yog los ntawm kev huam yuaj - tab sis vim nws cov metallurgical muaj pes tsawg leeg ncaj qha hais txog txhua qhov kev hem thawj loj uas dej hiav txwv nthuav tawm.

Dab tsi yog Duplex Stainless Hlau?

Duplex stainless hlau yog ib tsev neeg ntawm cov alloys nrog ob -theem microstructure: kwv yees sib npaug ntawm austenite thiab ferrite (li no lub npe "duplex"). Cov qauv siv lead ua sib xyaw no tsis yog kev sib tsoo - nws yog engineered los sau cov khoom zoo tshaj plaws ntawm ob theem.

Austenite theem(lub ntsej muag-centered cubic):xa cov toughness, ductility, thiab corrosion kuj.

Ferrite theem(lub cev-centered cubic):muab lub zog thiab ua haujlwm rau kev ntxhov siab corrosion cracking.

Qhov tshwm sim yog cov khoom siv ib txhij ua tau zoo dua qib austenitic (xws li 316L) hauv lub zog thiab SCC tsis kam, thaum tseem tshuav ntau dua corrosion-tiv taus dua li carbon lossis qis- alloy steels. Ib qho piv txwv tseem ceeb yog Pitting Resistance Equivalent Number (PREN), uas kwv yees cov khoom siv tiv thaiv pitting corrosion nyob rau hauv ib puag ncig chloride:

PREN=%Cr + 3.3 x %Mo + 16 x %N

Ib qho PREN saum toj 40 yog suav tias yog qhov yuav tsum tau ua rau kev pabcuam dej hiav txwv. Standard duplex 2205 ua tiav PREN ntawm ~ 35; super duplex 2507 ua tiav ~ 42. Carbon steel cov qhab nia qis dua 10.

Plaub Corrosion hem nyob rau txhua qhov Offshore Platform

Seawater muaj 19,000-35,000 ppm ntawm chloride ions. Cov ions aggressively tua cov passive oxide zaj duab xis ntawm stainless hlau, pib pits uas tuaj yeem nkag mus rau cov yeeb nkab phab ntsa hauv lub hlis. Txuj316L stainless hlau(PREN ~ 24) feem ntau tsis txaus. Super duplex 2507 (PREN ~ 42) tiv taus pitting txawm nyob hauv dej hiav txwv kub, stagnant.

SCC yog arguably qhov txaus ntshai tshaj plaws tsis ua hauj lwm hom nyob rau hauv offshore piping. Nws tshwm sim thaum peb yam xwm txheej tshwm sim: tensile stress, ib puag ncig corrosive (chlorides, H2S), thiab cov khoom raug. Austenitic stainless hlau - suav nrog 316L - yog qhov tsis zoo rau chloride SCC. Lub ferrite theem nyob rau hauv duplex alloys ua raws li ib tug tawg ntes, dramatically txhim kho SCC kuj. Hauv kev sim ntsuas ntawm 100 degrees Celsius hauv 1,000 ppm chloride tov, duplex 2205 qhia tias tsis muaj SCC tsis ua haujlwm, thaum 316L tsis ua haujlwm hauv qab 200 teev.

Siab - cov kua dej ntau tshaj tawm uas nqa cov xuab zeb ua rau yaig- corrosion - kev sib koom ua ke muaj kev puas tsuaj ntau dua li ob qho tib si. Lub zog ntau dua ntawm cov hlau duplex (450 MPa rau 2205 vs . 170 MPa rau 316L) txhais tau tias cov yeeb yaj kiab oxide tuab dua thiab ntau dua phab ntsa tsis kam rau ib chav tsev tuab, ncua kev pab cuam lub neej los ntawm 2 txog 4 piv rau qib austenitic.

Cov dej uas muaj H2S (kev pabcuam qaub, ib NACE MR0175 / ISO 15156) tsim cov atomic hydrogen uas diffuses rau hauv cov hlau thiab ua rau hlwv lossis tawg. Duplex qib nrog tswj cov ntsiab lus ferrite thiab qis hardness (HRC 28 max ib NACE cov qauv) dhau qhov kev pabcuam qaub, ua rau lawv haum rau ob qho tib si qab zib thiab qaub crude daim ntaub ntawv.

Kev sib piv ntawm cov khoom siv: Duplex vs. Alternatives

Cov lus hauv qab no nthuav qhia lub hom phiaj cov khoom siv thiab cov ntaub ntawv corrosion rau cov khoom siv yeeb nkab feem ntau raug soj ntsuam rau cov kev pabcuam sab nrauv. Tag nrho cov ntaub ntawv qhia txog ASTM / EN tus qauv yam tsawg kawg nkaus.

Cov peev txheej: ASTM A790, A928, A276; EN 10216-5; NACE technical reports. SCC tiv thaiv nyob rau hauv chloride-cov kabmob ib puag ncig ntawm 60-100 degrees C.

Qhov twg Duplex Stainless Steel Pipes siv rau Offshore Rigs

Duplex thiab super duplex yeeb nkab tshuab tshwm sim thoob plaws hauv ntug dej hiav txwv qhov twg dej hiav txwv, ua kua dej, los yog cov pa phem hu rau cov kav dej:

Kev txhaj tshuaj dej hiav txwv thiab cov dej tua hluav taws - 2507 super duplex yog tus qauv de facto rau siab - siab seawater txhaj tshuaj headers

Ntau lawm manifolds thiab flowlines - thauj cov roj crude tov nrog tsim dej thiab H2S

Cov txheej txheem saum toj kawg nkaus piping - cov khoom sib cais, cov cua txias, cov khoom siv hluav taws xob sib txuas, thiab cov kav dej sib txuas

Subsea umbilicals thiab risers - saj zawg zog thiab nruj riser systems nyob rau hauv dej tob tshaj 300 m

Cov kab hluav taws xob thiab cov dej siv hluav taws xob - qhov chaw dej hiav txwv txuas mus ntxiv

Flare headers thiab gas nqa kab - tuav siab - roj nrog condensate

Hauv dej tob thiab ultra- daim ntawv thov dej tob (dej qhov tob> 1,500 m), qhov kev kho yog kim heev lossis tsis yooj yim sua, rooj plaub ua lag luam rau duplex yuav ua rau muaj txiaj ntsig ntau dua.

Tus nqi tseeb ntawm kev txais cov khoom tsis raug

Cov neeg ua haujlwm qee zaum tiv thaiv cov yeeb nkab duplex raws li nws cov nqi pib ntau dua - feem ntau yog 2.5 mus rau 4 npaug ntawm cov khoom siv ntawm cov pa roj carbon steel ib meter. Qhov kev sib piv no ua rau tsis meej pem thaum cov nuj nqis hauv lub neej raug txiav txim siab.

Poob nyiaj tau los kwv yees li ntawm $500,000/hnub rau ib nrab - loj FPSO. Tus nqi tiag tiag txawv ntawm qhov chaw thiab tus neeg ua haujlwm. Cov ntaub ntawv muab tso ua ke los ntawm cov ntawv tshaj tawm HSE xwm txheej thiab kev lag luam tus nqi ntsuas.

Ib tug duplex yeeb nkab system feem ntau nqa ib tug 25-xyoo tsim lub neej nyob rau hauv offshore kev pab cuam. Cov pa roj carbon steel lossis txawm tias tus qauv austenitic stainless tshuab yuav tsum muaj kev tiv thaiv corrosion thiab kev tshuaj xyuas cov txheej txheem uas ntxiv cov nqi thoob plaws lub neej ua haujlwm. Thaum tag nrho cov nqi ntawm cov tswv cuab suav nrog 20-xyoo-laus lub neej, duplex tsis tu ncua muab kev siv nyiaj qis dua txawm tias tus nqi siab dua.

Xaiv qhov Zoo Duplex Qib rau Koj Daim Ntawv Thov

Tsis yog tag nrho cov duplex alloys sib npaug. Xaiv cov qib uas tsim nyog yuav tsum tau sib piv cov PREN, cov khoom siv kho tshuab, thiab cov kev pabcuam qaub rau qhov chaw ua haujlwm tiag tiag.

Tau qhov twg los: ASTM A790 / A928, EN 10216-5, NACE MR0175 / ISO 15156. PREN qhov tseem ceeb yog nominal; Cov hluav taws xob hluav taws xob tiag tiag yuav tsum raug txheeb xyuas raws li qhov project specification.

Rau feem ntau cov ntawv thov offshore, duplex 2205 muab qhov zoo tshaj plaws tshuav nyiaj li cas ntawm kev ua tau zoo thiab tus nqi. Qhov twg dej hiav txwv kub tshaj 30 degrees C los yog chloride concentrations siab heev, super duplex 2507 yog engineering specification ntawm kev xaiv.

Siv tau Standards thiab Specifications

Duplex stainless hlau yeeb nkab rau kev pab cuam offshore yuav tsum ua raws li cov txheej txheem nruj ntawm cov qauv thoob ntiaj teb. Cov ntaub ntawv tseem ceeb suav nrog:

ASTM A790 / A 928 - seamless thiab welded duplex stainless hlau yeeb nkab

NACE MR0175 / ISO 15156 - cov ntaub ntawv rau kev pabcuam qaub (H2S ib puag ncig)

ASME B31.3 thiab B31.8 - cov txheej txheem thiab cov kav dej xa hluav taws xob

DNV-ST-F101 - submarine pipeline systems (subsea applications)

ISO 21457 - kev xaiv cov ntaub ntawv rau seawater systems

ASTM A923 - kuaj xyuas cov theem sib txawv ntawm cov hlau hauv duplex

Kev yuav khoom ntawm cov yeeb nkab duplex yuav tsum suav nrog cov ntawv pov thawj ntawm cov tshuaj lom neeg muaj pes tsawg leeg, PREN pov thawj, kuaj tshuab (UTS, yield, cuam tshuam ntawm -46 ° C), thiab, rau kev pabcuam qaub, kev txheeb xyuas qhov nyuaj ntawm NACE MR0175. Tag nrho cov ntaub ntawv traceability los ntawm tshav kub mus rau kev teeb tsa yog qhov yuav tsum tau ua ntawm feem ntau cov dej num offshore.

Cov lus nug nquag

Yog lawm. Duplex 2205 thiab 2507 yog niaj hnub welded nyob rau hauv offshore fabrication yards thiab thaum lub sij hawm installation. Qhov kev xav tau tseem ceeb yog kev tswj xyuas cov cua sov thiab kev sib tshuam ntawm qhov kub thiab txias kom tswj tau qhov sib npaug ntawm austenite -ferrite piv thiab tsis txhob nag lossis daus ntawm sigma theem. Cov txheej txheem vuam tsim nyog raws li ASME IX lossis ISO 15614-1 thiab cov vuam vuam uas tau lees paub yog yuav tsum tau ua.

Nickel alloys xws li Inconel 625 muaj kev tiv thaiv corrosion zoo dua tab sis raug nqi 8 txog 15 npaug ntau dua li duplex ib kilogram. Rau feem ntau offshore topside thiab subsea piping, super duplex 2507 muab kev ua tau zoo txaus ntawm ib feem ntawm tus nqi. Nickel alloys tau tshwj tseg rau cov kev pabcuam hnyav tshaj plaws - xws li cov raj xa dej hauv ultra-cov dej qab zib - qhov twg duplex tsis suav nrog.

Duplex thiab super duplex sawb yog dav siv los ua lub siab armor thiab sab hauv carcass khaubncaws sab nraud povtseg nyob rau hauv saj zawg zog riser systems. Lub zog siab -rau- qhov hnyav piv txo qhov kev sib zog ua haujlwm zoo hauv cov riser, qhov txiaj ntsig tseem ceeb hauv cov ntawv thov dej tob uas qhov hnyav nce siab dhau los ua qhov txwv tsim.

Xaus

Duplex stainless hlau kav tsis yog ib qho kev xaiv zoo tshaj plaws rau offshore roj rigs - lawv yog cov txheej txheem engineering uas ua rau muaj kev nyab xeeb, txhim khu kev qha, thiab kev lag luam tawm sab nrauv tuaj yeem ua tau. Lawv dual-theem microstructure ncaj qha hais txog plaub qhov kev hem thawj corrosion nyob rau hauv cov dej hiav txwv thiab tsim tawm- dej ib puag ncig. Lawv lub zog-rau- qhov hnyav kom zoo dua txo cov qauv thauj khoom. Thiab lawv lub peev xwm ua haujlwm 25 xyoo tshem tawm cov nqi tshuaj ntsuam xyuas thiab hloov cov voj voog uas cuam tshuam cov pa roj carbon steel.

Rau ib qho kev ua haujlwm sab nrauv - los ntawm brownfield hloov kho tshiab mus rau cov dej tob FPSO tshiab - kev txiav txim siab xaiv cov khoom yuav tsum pib nrog duplex stainless hlau raws li lub hauv paus thiab ua hauj lwm sab nraud los ntawm qhov ntawd raws li kev pabcuam hnyav thiab kev txwv nyiaj txiag. Kev qhia txog cov pa roj carbon steel lossis cov qib alloy tsis txaus kom txuag tau cov peev txheej pib yog qhov kev txiav txim siab tias kev lag luam kev lag luam ntawm thaj chaw yuav rau txim rau ntau xyoo.

ASTM A790 / A928M - Duplex Stainless Steel Pipe Standards

NACE MR0175 / ISO 15156 - Petroleum Industries: Cov ntaub ntawv siv rau hauv H2S- Muaj Ib puag ncig

DNV-ST-F101: Submarine Pipeline Systems

Norwegian PSA (2019) - Hydrocarbon Leak Statistics rau Norwegian Continental txee

NACE International Technical Report 6A194: Erosion-Corrosion in Oilfield Environments

ASME B31.3 Txheej Txheem Piping Code

TS EN ISO 21457 Petroleum, Petrochemical thiab Natural Gas Kev Lag Luam Kev Lag Luam - Kev Xaiv Cov Khoom Siv thiab Kev Tiv Thaiv Corrosion

© 2025 - Technical Content Series. Txhua txoj cai. Reproduction nrog attribution tso cai.