Dab tsi yog qhov zoo ntawm kev siv Nickel-Raws li Alloys rau Boiler Superheater Tubes hauv Cov Hluav Taws Xob Hluav Taws Xob?
1.1 Zoo heev High -Tsub Mechanical Properties
Siab creep thiab rupture kuj: Nickel-raws li alloys (piv txwv li, Inconel 625, Hastelloy X) tso siab rau cov khoom siv ntxiv dag zog rau cov ntsiab lus (Cr, Mo, W) thiab nag lossis daus hnyav theem (', '') txhawm rau tiv thaiv kev txav mus los ntawm qhov kub thiab txias. Lawv cov creep rupture lub neej ntawm 650℃thiab 100 MPa tuaj yeem tshaj 10,000 teev, uas yog 3-5 npaug ntev dua li cov cua sov- tiv taus martensitic steels. Qhov no tiv thaiv cov hlab ntsha ntxov ntxov tshwm sim los ntawm kev nkag mus deformation nyob rau hauv ntev - lub sij hawm siab - qhov kub thiab txias.
Zoo thermal qaug zog tsis kam: Thaum lub sijhawm pib- nce thiab kaw ntawm lub zog hluav taws xob thermal, cov raj superheater tau ua rau cua sov thiab cua txias, ua rau thermal qaug zog. Qhov qis thermal expansion coefficient thiab siab thermal conductivity ntawm npib tsib xee-raws li alloys txo thermal kev nyuaj siab tsub zuj zuj, txhim khu kev tiv thaiv thermal qaug zog tawg.
1.2 Superior Corrosion thiab Oxidation Resistance
Tsis kam mus siab -kub oxidation: Nickel-raws li alloys tsim ib ntom, adherent Cr₂O₃ tiv thaiv zaj duab xis rau saum npoo ntawm qhov kub thiab txias, uas zoo thaiv qhov nkag ntawm oxygen thiab corrosive media. Txawm tias nyob rau ntawm 700 degree, oxidation tus nqi yog tsawg dua 0.01 hli / xyoo, deb tshaj li ntawm cov tsoos cua sov-resistant steels.
Resistance rau corrosion los ntawm flue gas thiab tshauv: Cov pa roj hauv cov hluav taws xob thermal muaj SO₂, HCl, thiab alkali hlau ntsev (xws li Na₂SO₄, K₂SO₄). Cov tshuaj no cuam tshuam nrog lub raj nto kom tsim qis- melting-point eutectics, ua rau siab - kub corrosion thiab tshauv corrosion. Nickel-raws li alloys nrog siab Mo thiab W cov ntsiab lus tuaj yeem tiv thaiv kev yaig ntawm cov xov xwm corrosive, tsis txhob pitting thiab thinning ntawm lub raj phab ntsa.
1.3 Lub zog ruaj khov
Nickel-raws li alloys tuav lub ntsej muag ruaj khov-centered cubic (FCC) siv lead ua qauv nyob rau hauv kev khiav hauj lwm kub ntawm superheaters, yam tsis muaj kev hloov pauv theem (xws li, martensitic transformation) uas tshwm sim hauv qee cov cua sov-cov hlau tsis muaj zog. Qhov no ua kom cov khoom ua haujlwm zoo ib yam thaum lub sijhawm ua haujlwm ntev -.
Cov ntsiab lus xws li Ti thiab Nb nyob rau hauv cov alloy daim ntawv ruaj khov carbides, uas pin lub lis ciam teb thiab tiv thaiv grain coarsening ntawm qhov kub thiab txias, ntxiv txhim kho cov qauv stability ntawm cov hlab.
1.4 Kev Pabcuam Sijhawm Ntxiv thiab txo cov nqi tu
Lub neej kev pab cuam ntawm npib tsib xee-raws li alloy superheater raj tuaj yeem ncav cuag 20-30 xyoo, uas yog ob zaug ntev npaum li cov cua sov ib txwm muaj-cov kav hlau tsis muaj zog (10-15 xyoo). Qhov no txo qhov zaus ntawm kev hloov raj thiab chav tsev downtime.
Qhov zoo tshaj plaws corrosion kuj txo lub raj phab ntsa thinning thiab to txaus txaus ntshai, txo tus nqi tu ntawm boiler system thiab txhim kho kev ua hauj lwm kev ntseeg siab ntawm thermal fais fab nroj tsuag.
2. Dab tsi yog npib tsib xee-Based Alloys tsim nyog rau siab -Tub thiab siab- Cov kav dej hauv kev lag luam Petrochemical?
2.1 Inconel 625 - Zoo tagnrho rau General High-Tsuas Kub thiab Siab-Hloov Corrosive Conditions
Cov ntsiab lus tseem ceeb: Ni-Cr-Mo-Nb alloy nrog 21% Cr, 9% Mo, thiab 3.6% Nb.
Core zoo: Muab cov tshuaj zoo heev ntxiv dag zog rau cov nyhuv thiab corrosion kuj. Nws muaj zog tiv taus pitting corrosion, crevice corrosion, thiab kev nyuaj siab corrosion cracking (SCC) nyob rau hauv chloride -muaj xov xwm. Nb cov ntsiab lus tsim cov carbide ruaj khov, txhim kho siab - qhov kub thiab txias ntawm cov qauv kev ruaj ntseg. Nws tuaj yeem ua haujlwm ruaj khov ntawm qhov kub txog li 980℃thiab tsim nyog rau siab -cov kav dej hauv cov tshuab flue gas desulfurization (FGD) thiab hydrocracking units.
Tej kev siv: Petrochemical hydrocracking reactor qhov hluav taws xob cov kav dej, cov kav dej hloov kho qhov cub, thiab siab -cov kav dej kub.
2.2 Hastelloy X – Nyiam rau Ultra-High-Tsub Oxidizing Ib puag ncig
Cov ntsiab lus tseem ceeb: Ni-Cr-Co-Mo alloy nrog 22% Cr, 9% Mo, thiab 18% Co.
Core zoo: Zoo heev -kub oxidation kuj thiab thermal qaug zog tsis kam. Nws tuaj yeem tswj xyuas cov khoom zoo hauv oxidizing flue gas ib puag ncig ntawm 1000 degree, thiab muaj qhov zoo tshaj plaws weldability. Cov ntsiab lus siab Co txhim kho cov hlau nplaum tsis kam ntawm qhov kub thiab txias, ua rau nws tsim nyog rau cov kav dej hauv siab - kub cua sov rauv taws thiab tawg qhov cub.
Tej kev siv: Ethylene cracking furnace radiant section pipes, high -kub flue gas pipelines in petrochemical plants.
2.3 Hastelloy C276 - Zoo rau Corrosive High-Tsuas Kub thiab Siab- Ib puag ncig Siab
Cov ntsiab lus tseem ceeb: Ni-Cr-Mo-W alloy nrog 15.5% Cr, 16% Mo, thiab 4% W.
Core zoo: Paub tias yog "universal corrosion{0}}resistant alloy", nws muaj kev tiv thaiv zoo heev los txo thiab oxidizing sib xyaw acids, nrog rau chloride ion corrosion. Nws tuaj yeem tiv taus corrosion ntawm hydrogen sulfide, sulfuric acid, thiab organic acids nyob rau hauv siab - kub thiab siab - ib puag ncig siab. Nws yog tsim rau cov kav dej hauv cov txheej txheem nrog ob qho tib si muaj zog corrosion thiab siab siab, xws li sulfur rov qab units thiab acid gas kho tshuab.
Tej kev siv: Petrochemical acid gas kis pipelines, sulfuric acid alkylation unit kav.
2.4 Inconel 718 - Haum rau High -Tsuas Kub thiab Siab - Kev Ruaj Siab Ib puag ncig Yuav Tsum Muaj Lub Zog
Cov ntsiab lus tseem ceeb: Ni-Cr-Fe-Nb alloy nrog 19% Cr, 5% Nb, thiab 3% Mo.
Core zoo: Cia siab rau '' theem nag lossis daus ntxiv, nws muaj ultra- lub zog tensile siab (dhau 1300 MPa) thiab tawm lub zog ntawm qhov nruab nrab kub (400-650℃). Nws kuj muaj qhov zoo corrosion kuj, ua rau nws haum rau siab -kub thiab siab - cov kav dej siab uas yuav tsum tau dais cov neeg kho tshuab kev ntxhov siab Resistant rau kev ntxhov siab corrosion cracking thiab creep deformation.
Tej kev siv: Siab- cov kav dej siab hauv cov khoom siv petrochemical qhov zoo, siab - kub thiab siab - cov kav dej siab hauv cov roj av sab nrauv.
