Njira Zowotcherera Zitsulo za Nickel za Makampani Opanga Mafuta
Makampani opanga mafuta amagwira ntchito m'mikhalidwe yovuta: kutentha kwambiri, kupanikizika kwambiri, komanso kukhudzidwa ndi zinthu zowononga monga chloride, sulfure, H₂S, CO₂, ndi zinthu zosiyanasiyana za asidi. M'malo awa, kusankha zinthu ndikofunikira kwambiri pa kudalirika kwa zida zopangira. Zitsulo zopangidwa ndi nickel (nickel ndi alloys zake) zimagwiritsidwa ntchito kwambiri chifukwa cha kukana dzimbiri bwino, kukhazikika kwa kutentha kwambiri, komanso kuthekera kolimbana ndi kusweka kwa dzimbiri. Komabe, zabwinozi zitha kupezeka pokhapokha ngati njira yowotcherera ikuchitika pogwiritsa ntchito njira yoyenera, chifukwa kuwotcherera kumatha kusintha kapangidwe kake ka zinthuzo, kuyambitsa ming'alu yotentha, kutseguka kwa pores, kapena kuchepetsa kukana dzimbiri m'dera la weld.
1. Udindo wa nickel alloys mu petrochemicals
Ma aloyi a nikeli monga Nickel 200/201, Monel (Ni-Cu), Inconel (Ni-Cr-Fe), Incoloy, ndi Hastelloy (Ni-Mo-Cr) amagwiritsidwa ntchito kwambiri mu zosinthira kutentha, ma distillation columns, ma reactor, ma process piping, zida zochotsera sulfurization, ndi machitidwe omwe amagwira ntchito ndi ma acid ndi ma chloride. Mwachitsanzo, ma aloyi a Ni-Cr ali ndi kukana kwabwino kwa okosijeni kutentha kwambiri, pomwe ma aloyi a Ni-Mo ndi abwino kwambiri pochepetsa malo ndi mayankho ena a asidi. Kulukana ma aloyi amenewa kumafuna kusunga kapangidwe ka aloyi kuti asunge kukana kwa dzimbiri bwino.
2. Mavuto apadera pakuwotcherera nickel
Kawirikawiri, ma alloy a nickel ali ndi kutentha kochepa kuposa chitsulo cha kaboni komanso kuchuluka kwa kutentha komwe kumawonjezeka. Kuphatikiza kumeneku kumapangitsa kuti kutentha kukhale kwakukulu m'dera la weld ndipo kungapangitse kuti kusokonezeke. Kuphatikiza apo, ma alloy ena a nickel amakhudzidwa ndi:
– Kusweka kwa kutentha (kusweka kolimba) chifukwa cha kulekanitsidwa kwa zinthu pamalire a tirigu panthawi yolimbitsa chitsulo chosungunula.
- Kubowola kwa mpweya nthawi zambiri kumachitika chifukwa cha kuipitsidwa, chinyezi, kapena mpweya wotsekedwa.
- Kuchepetsa kapena kuchepetsa kukana dzimbiri m'deralo ngati njira yowotcherera si yolondola, makamaka pa zinthu zina zosungunulira.
– Kuipitsidwa ndi chitsulo/kaboni kuchokera ku zida zogwirira ntchito zachitsulo kungachepetse kukana dzimbiri, makamaka m'malo okhala ndi mankhwala amphamvu.
Chifukwa chake, kuwongolera ukhondo, kusankha zodzaza, ndi magawo a kutentha ndizofunikira kwambiri.
3. Kusankha njira zowotcherera: GTAW, GMAW, SMAW, ndi SAW
Njira zina zodziwika bwino zowotcherera ma alloys a nickel mu petrochemicals ndi izi:
a) GTAW (TIG)
GTAW nthawi zambiri ndiyo njira yabwino kwambiri yogwiritsira ntchito mizu ya mapaipi, ntchito yolondola, ndi zinthu zopyapyala. Ubwino wake ndi monga kulamulira kutentha bwino komanso kusungunula bwino. Kuteteza mpweya wa argon woyera nthawi zambiri kumagwiritsidwa ntchito; m'magwiritsidwe ena, helium ikhoza kuwonjezeredwa kuti ipititse patsogolo kulowa kwa madzi.
b) GMAW (MIG) ndi pulsed GMAW
GMAW ndi yoyenera kupanga mwachangu, makamaka popanga zinthu m'mafakitale. Njira yolumikizira imathandizira kuchepetsa kutentha ndi kufalikira kwa madzi, komanso kukonza kuwongolera m'malo ovuta olumikizira. Waya wolumikizira uyenera kusungidwa ndikusamalidwa bwino kuti upewe kuipitsidwa.
c) SMAW (kuwotcherera kwa ma electrode)
SMAW imagwiritsidwa ntchito kwambiri pokonza minda chifukwa cha zida zake zosavuta. Komabe, zoopsa za hydrogen pickup ndi slag ziyenera kulamulidwa mwa kusankha ma electrode moyenera, njira zophikira ma electrode, ngati kuli kofunikira, komanso njira zoyeretsera pakati pa zigawo.
d) KUSAW
SAW imagwira ntchito bwino pa mbale zokhuthala ndi zolumikizira zazitali, monga pa zotengera zopanikizika kapena zipolopolo. Kusankha kwa Flux ndi waya kuyenera kukhala koyenera kuti zitsimikizire kuti kapangidwe ka chitsulo cholumikiziracho kamakhalabe ndi kukana dzimbiri komwe kukufunika.
4. Kukonzekera zinthu ndi kuyeretsa pamwamba
Kupambana kwa kuwotcherera kwa nickel alloy kumakhudzidwa kwambiri ndi kukonzekera pamwamba. Njira zodziwika bwino mumakampani opanga mafuta ndi monga:
- Kuchotsa mafuta ndi chosungunulira choyenera kuti muchotse mafuta/mafuta.
– Tsukani oxide pogwiritsa ntchito burashi yapadera yachitsulo chosapanga dzimbiri (musagwiritse ntchito burashi yachitsulo cha kaboni).
- Kugwiritsa ntchito zida zosiyana: zopukusira, ma flap disc, ndi maburashi ziyenera kugwiritsidwa ntchito makamaka pazinthu zopangidwa ndi nickel/zosapanga dzimbiri kuti zisaipitse zinthu.
- Kukonza nthawi zonse ndi kuwongolera mipata kuti muchepetse chiopsezo cha kusowa kwa fusion kapena burn-through.
Ngakhale zinthu zazing'ono zodetsa zimatha kuyambitsa ma pores ndikuchepetsa ubwino wa weld bead.
5. Kusankha ndi kugwirizana kwa zitsulo zodzaza
Kusankha zitsulo zodzaza sikuyenera kungokhala pa mfundo yakuti "zinthu zimafanana ndi zinthu". Mu ntchito ya petrochemical, zodzaza nthawi zambiri zimasankhidwa kuti zithandizire kukana ming'alu ndi dzimbiri. Zitsanzo za mfundo zazikulu:
- Gwiritsani ntchito chodzaza chomwe chili ndi mphamvu yolimbana ndi kutentha komanso chosakaniza chomwe chimathandizira kulimba kokhazikika.
– Pakuwotcherera kosiyana (monga nickel alloy ku chitsulo chosapanga dzimbiri kapena alloy), chodzaza cha nickel china nthawi zambiri chimasankhidwa chomwe chimatha kupirira kusiyana kwa kutentha komwe kumakula ndikuchepetsa mavuto ochepetsa kutentha.
- Onetsetsani kuti chodzazacho chikukwaniritsa miyezo yoyenera ya AWS/ASME komanso chikukwaniritsa zofunikira za polojekiti.
Mu ntchito zambiri, mbali ya dzimbiri imakhala yolimba kuposa mphamvu yokoka kotero kusankha zodzaza kumatanthauza luso la ntchito ndi malingaliro a ma code.
6. Kulamulira kutentha komwe kumalowetsa, kutentha koyambirira, ndi kutentha kwa interpass
Ma alloy a nickel nthawi zambiri safuna kutentha kwambiri monga zitsulo zina za alloy, koma kuwongolera kutentha ndikofunikirabe:
- Kutentha kwambiri kumatha kukulitsa HAZ (malo omwe akhudzidwa ndi kutentha), kuonjezera kusokonekera, ndikuwonjezera mwayi wopatukana komwe kumayambitsa ming'alu yotentha.
– Kutentha kwa interpass kuyenera kutetezedwa kuti kusakhale kokwera kwambiri, kuti kapangidwe kake ndi kukana dzimbiri ziwongoleredwe.
- Njira zotumizira ma current/voltage nthawi zambiri zimagwiritsidwa ntchito pa ma plate okhuthala kuti zisunge bwino.
Magawo enieni nthawi zambiri amatsimikiziridwa kudzera mu WPS (Welding Procedure Specification) ndikuyesedwa kudzera mu PQR (Procedure Qualification Record).
7. Njira zowotcherera kuti muchepetse zolakwika
Njira zina zothandiza zomwe nthawi zambiri zimagwiritsidwa ntchito powotcherera nickel pa mankhwala a petrochemicals:
- Mikanda yopyapyala ndi yabwino kwambiri kuposa yoluka mozungulira, kuti ichepetse kutentha komwe kumalowa komanso kuchepetsa kulekanitsa.
- Kuyeretsa pakati pa zitseko ndikofunikira kwambiri, makamaka pa SMAW ndi SAW, kuti tipewe kuphatikizidwa kwa zinyalala.
– Kulamulira kuyambira ndi kuyimitsa: phirilo liyenera kudzazidwa bwino kuti phirilo lisasweke.
- Kuchotsa msana pa GTAW payipi yolumikizira (yokhala ndi argon) kuti mizu ya mkanda isawonongeke ndi okosijeni.
- Gwiritsani ntchito mpweya wabwino woteteza ndikuwonetsetsa kuti palibe kutuluka kwa madzi komwe kumayambitsa kukhuthala kapena kufooka kwa mpweya.
8. Chithandizo cha kutentha pambuyo pa weld (PWHT) ndi zinthu zina zokhudzana ndi zitsulo
Si ma aloyi onse a nickel omwe amafunikira PWHT. Nthawi zambiri, PWHT imatha kuyambitsa mvula m'magawo ena, zomwe zimachepetsa kukana dzimbiri kapena kulimba, kutengera mtundu wa aloyi. Chifukwa chake:
- PWHT imachitika pokhapokha ngati pakufunika ndi code (ASME) kapena kapangidwe kake, kapena ngati chinthu china chikufunikira.
– Kuwunika chiopsezo cha mvula ya carbide/intermetallic phase kuyenera kuganizira kutentha kwa ntchito ndi malo owononga.
- Pa ntchito zina, kupopera madzi kapena kutentha kwapadera kungafunike, koma nthawi zambiri izi zimachitika pamalo oyenera komanso kutengera zomwe zidapangidwa.
9. Kuyang'anira, kuyesa ndi miyezo yogwiritsidwa ntchito
Mu petrochemicals, kuwotcherera pa zinthu za nickel nthawi zambiri kumatsatira ASME Section IX pa njira ndi ziyeneretso za wowotcherera, ndi ASME Section VIII (zotengera zopanikizika) kapena B31.3 (mapaipi opangira). Njira zowunikira zodziwika bwino zimaphatikizapo:
– VT (Kuyesa Kuwoneka) kuti muwone mawonekedwe a mikanda, kudula mochepa, ndi kuphatikana.
– PT (Liquid Penetrant Testing) ndi yothandiza pozindikira ming'alu pamwamba pa zinthu zopanda ferromagnetic.
- RT/UT kuti azindikire zolakwika zamkati monga ma porosity, kusowa kwa fusion, kapena slag integration.
- Mayeso ena monga kuyeza kwa ferrite (ngati kuli koyenera), kuyesa kuuma, kapena kuyesa dzimbiri angafunike kutengera ntchitoyo.
Ubwino wa zolemba (WPS, PQR, WPQ, kutsata zinthu, kuchuluka kwa kutentha) ndikofunikira kwambiri pamapulojekiti a petrochemical.
10. Kesimpulan
Njira zowotcherera zitsulo za nickel m'makampani opanga mafuta zimafuna kutsatira kwambiri ukhondo, kusankha njira ndi zodzaza, komanso kuwongolera kutentha. Ma alloy a nickel amapereka magwiridwe antchito abwino kwambiri m'malo owononga komanso otentha kwambiri, koma kukhudzidwa kwawo ndi kuipitsidwa ndi kusweka kwa kutentha kumafuna kapangidwe kokhwima ndikugwiritsa ntchito njira zowotcherera. Kudzera mu kukhazikitsa bwino kwa WPS, kuwongolera magawo, njira zoyenera zowotcherera, komanso kuwunika bwino motsatira miyezo ya ASME, malo olumikizirana opangidwa ndi nickel amatha kukhala odalirika kwa nthawi yayitali ndikuchepetsa chiopsezo cha kulephera kwa zida zofunika kwambiri m'malo opangira mafuta.
Ngati mukufuna, nditha kusintha nkhaniyi kuti ikhale yaukadaulo kwambiri pophatikiza zitsanzo za WPS (current/voltage range, shielding gas type, maximum interpass), kapena kuyang'ana kwambiri pa alloy imodzi monga Inconel 625 kapena Hastelloy C-276.
