ntub dej - txheej txheem phosphoric acid (WPA) yog ib qho ntawm cov dej corrosive tshaj plaws nyob rau hauv kev lag luam chemical processing, combining free sulfuric acid, fluoride, chloride, thiab abrasive solids nyob rau hauv ib tug kwj. Thaum tshav kub kub exchangers nyob rau hauv lub digestion, pom, thiab evaporation seem ntawm ib tsob nroj WPA pom qhov kev tawm tsam no concentrated nyob rau hauv ceev, kub, thiab weld qhov chaw - raws nraim qhov uas tsis ua hauj lwm yog kim tshaj.Incoloy 825 (UNS N08825) Cov.tau dhau los ua cov hlau ua haujlwm rau lub luag haujlwm no vim tias nws cov nickel -chromium- molybdenum- tooj liab chemistry tau tsim tshwj xeeb los tiv thaiv ob qho tib si txo sulfuric / phosphoric acid nres thiab hauv zos chloride corrosion tib lub sijhawm.
Cov lus qhia no piav qhia txog vim li cas Incoloy 825 ua tau zoo hauv WPA cov khoom siv hluav taws xob sib hloov, nws piv rau 316L stainless hlau thiab cov nickel alloys siab dua, thiab cov qauv tsim thiab kev tsim khoom yuav tsum tau ua kom tau txais nws lub neej kev pabcuam tag nrho.
Incoloy 825 yog dab tsi, thiab Vim li cas thiaj siv dav hauv Phosphoric Acid Production?
Incoloy 825 yog npib tsib xee- hlau-chromium alloy nrog ntxiv molybdenum thiab tooj liab, tshwj xeeb tsim los tiv thaiv kev sib xyaw sulfuric acid, phosphoric acid, thiab chloride / fluoride nres pom nyob rau hauv ntub- txheej txheem phosphoric acid, uas yog vim li cas nws tau dhau los ua cov txheej txheem ntau lawm ntawm WPA.
|
Element (wt%) |
Incoloy 825 (UNS N08825) Cov. |
|
Nickel (Ni) |
38.0–46.0 |
|
Chromium (Cr) |
19.5–23.5 |
|
Molybdenum (hli) |
2.5–3.5 |
|
Copper (Cu) |
1.5–3.0 |
|
Hlau (Fe) |
Qhov nyiaj tshuav (Ntau dua lossis sib npaug rau 22.0) |
|
Titanium (Ti) |
0.6–1.2 |
|
Cov pa roj carbon (C) |
Tsawg dua los yog sib npaug li 0.05 |
Table 1 - Cov neeg sawv cev tshuaj muaj pes tsawg leeg ntawm Incoloy 825 rau ASTM B424/B425/B163.
Lub alloy qhov sib ntxiv ntawm tooj liab yog tus yuam sij rau nws txoj kev tiv thaiv kom tsis txhob muaj cov kua qaub xws li sulfuric thiab phosphoric acid, thaum nws cov ntsiab lus molybdenum ntxiv tsis kam rau pitting thiab crevice corrosion los ntawm chloride ions. Nws cov ntsiab lus siab nickel (38-46%) tiv thaiv chloride kev nyuaj siab corrosion tawg, hom tsis ua haujlwm uas txwv cov qauv austenitic stainless hlau zoo li 316L hauv qhov kev pabcuam no. Vim tias ntub dej - txheej txheem phosphoric acid muaj tag nrho cov hom kev txhoj puab heev ib txhij - sulfuric acid los ntawm kev zom cov kauj ruam, fluoride los ntawm cov pob zeb phosphate, thiab chloride ua cov kab mob - Incoloy 825's balanced multi-element resistance} feem ntau ntawm cov nroj tsuag {0race. xav tau ib qho txawv tshwj xeeb alloy rau txhua hom corrosive.
Dab tsi ua rau ntub dej -Cov txheej txheem Phosphoric Acid thiaj li ua rau cov khoom siv hluav taws xob kub hloov pauv?
Kev ntub dej - txheej txheem phosphoric acid yog nruj heev vim nws muab plaub cais cov txheej txheem corrosion nyob rau hauv ib lub kwj - dawb sulfuric acid nres, fluoride- nrawm corrosion, chloride-induced pitting thiab kev nyuaj siab corrosion cracking, thiab solids-tsav corrosion ib yam ntawm cov hlau{5} {5} nyob ib leeg, cia ib leeg plaub ua ke.
Dawb sulfuric acid: WPA yog tsim los ntawm kev zom cov pob zeb phosphate nrog sulfuric acid, thiab tswj tau ntau tshaj ntawm cov sulfuric acid uas tsis muaj kev cuam tshuam feem ntau nyob hauv cov txheej txheem kwj dej, tawm tsam cov ntaub ntawv uas tsis muaj zog txo -acid resistance.
Cov ntsiab lus fluoride: Phosphate pob zeb muaj fluorapatite, uas tso tawm fluoride ions thaum lub sij hawm zom mov; Cov tshuaj fluoride tuaj yeem ua rau hauv zos ua kom tsis muaj zog oxide zaj duab xis thiab ua kom corrosion, tshwj xeeb tshaj yog nyob rau hauv siab concentration lossis siab kub.
Chloride contamination: Chloride nkag los ntawm cov ore, cov txheej txheem dej, los yog cov kab mob ntws, thiab ua rau thaj chaw pitting thiab crevice corrosion, thiab nyob rau hauv cov xwm txheej hnyav, chloride kev nyuaj siab corrosion tawg ntawm cov alloys raug.
Tshem tawm cov khib nyiab thiab slurry yaig: WPA nqa cov gypsum zoo thiab cov pob zeb uas tsis muaj kev cuam tshuam, uas ua rau cov oxide tiv thaiv cov yeeb yaj kiab ntawm qhov siab tshaj plaws, tshwj xeeb tshaj yog nyob rau hauv lub raj inlets, khoov, thiab baffle tiv tauj cov ntsiab lus hauv cov khoom siv hluav taws xob.
Yuav ua li cas Incoloy 825 tiv thaiv Corrosion hla txawv WPA Concentrations thiab Kub?
Incoloy 825 tuav tus nqi qis, kwv yees dav dav dav dav dav thoob plaws qhov ntub dej ib txwm- txheej txheem cov kua qaub los ntawm dilute 28-30% P2O5 lim kua qaub los ntawm cov khoom siv concentrated 40-54% P2O5 evaporator, tab sis tus nqi corrosion nce nrog ob qho tib si nce kub thiab nce fluoride / chloride paug, uas yuav tsum tau muab tso rau hauv kev sib pauv.
|
Txheej txheem theem |
Hom P2O5 Concentration |
Qhov kub thiab txias |
Incoloy 825 Kev ua haujlwm |
|
Kev zom / lim (tsis muaj kua qaub) |
~28–30% |
60-80 degree |
Zoo heev general corrosion kuj; txheem dej num |
|
Thawj -theem evaporation |
~30–40% |
70-90 degree |
Kev ua haujlwm zoo; Saib xyuas qib fluoride/chloride |
|
Thaum kawg evaporation (tub lag luam- qib acid) |
~40–54% |
90-110 degree |
Tsim nyog tab sis yuav tsum tau saib xyuas kom zoo; siab tshaj - thaj tsam hnyav tuaj yeem lav qhov siab dua alloy |
Tmuaj peev xwm 2 - Tus neeg sawv cev ntub dej- txheej txheem phosphoric acid tej yam kev mob los ntawm theem tsim khoom thiab Incoloy 825 qhov kev ua tau zoo dav dav. Tus nqi corrosion tiag yog nyob ntawm cov tshuaj cog qoob loo (fluoride, chloride, thiab sulfate qib) thiab yuav tsum tau lees paub los ntawm kev kuaj daim coupon lossis keeb kwm ntawm tsob ntoo.
Incoloy 825 Muab piv rau 316L Stainless Hlau li cas hauv WPA Kev Pabcuam Kub Kub Exchanger?
Incoloy 825 ua tau zoo tshaj 316L stainless hlau nyob rau hauv ntub dej - txheej txheem phosphoric acid kev pab cuam, tshwj xeeb tshaj yog hais txog pitting, crevice corrosion, thiab chloride stress corrosion cracking, uas yog vim li cas 316L feem ntau txwv rau qis dua - hnyav, qis dua - chloride kev sib pauv ntawm PA 8 feem ntau thaum nyob rau hauv lub luag haujlwm.
|
Khoom |
316L Stainless hlau |
lus 825 |
|
Nickel cov ntsiab lus |
10.0–14.0% |
38.0–46.0% |
|
Cov ntsiab lus molybdenum |
2.0–3.0% |
2.5–3.5% |
|
Chloride SCC kuj |
txwv; susceptible saum nruab nrab chloride / kub |
Zoo; cov ntsiab lus nickel siab tiv thaiv SCC pib |
|
Kev tiv thaiv dav dav kom txo cov kua qaub (H2SO4 / H3PO4 sib tov) |
Nruab nrab |
Zoo heev, pab los ntawm tooj liab ntxiv |
|
Tus nqi txheeb ze ntawm ib chav tsev loj |
1.0x (lub hauv paus) |
~2.5x – 3.5x |
|
Lub luag hauj lwm ntawm WPA heat exchanger |
Tsawg -chloride, qis dua - lub luag haujlwm hnyav; qee cov nroj tsuag tsuas yog siv qhov twg cov kua qaub zoo - tswj |
Standard alloy rau feem ntau cov txheej txheem kub exchangers, agitators, thiab piping |
Table 3 - Cov khoom sib piv ntawm 316L stainless hlau thiab Incoloy 825 rau ntub - txheej txheem phosphoric acid. Tus nqi txheeb ze yog qhov taw qhia nkaus xwb thiab sib txawv nrog cov nqi lag luam nickel / molybdenum.
Yuav ua li cas Incoloy 825 piv rau siab dua Alloys zoo li Alloy 625 nyob rau hauv Feem ntau hnyav Zones?
Xaus:Hauv thaj chaw hnyav tshaj plaws ntawm WPA tsob nroj - cov ntsiab lus fluoride siab heev, chloride siab, lossis siab tshaj -kub evaporator theem - Alloy 625 los yog siab zoo sib xws - molybdenum nickel alloys tuaj yeem ua tau zoo dua Incoloy 825, tab sis qhov no ntxiv cov nqi 625 yog li tshwj xeeb rau txhua qhov tshwj xeeb. siab- cov khoom pheej hmoo ntau dua li siv thoob plaws hauv cov nroj tsuag.
|
Khoom |
lus 825 |
alloy 625 |
|
Cov ntsiab lus molybdenum |
2.5–3.5% |
8.0–10.0% |
|
Pitting/crevice resistance nyob rau hauv siab -chloride, siab - fluoride aav |
Zoo |
Zoo heev |
|
Tus nqi txheeb ze tus nqi ib chav tsev loj (vs. 316L=1.0x) |
~2.5x – 3.5x |
~5x – 7x |
|
Ib qho WPA daim ntawv thov |
General txheej txheem kub exchangers, piping, agitators |
Qhov siab tshaj plaws - cov khoom hnyav: thaj chaw tshwj xeeb evaporator, tshuab ntxhua khaub ncaws, lossis cov chaw paub txog teeb meem txheeb xyuas los ntawm cov keeb kwm cog qoob loo |
Table 4 - Incoloy 825 piv rau Alloy 625 rau qhov xav tau tshaj plaws ntub dej - txheej txheem phosphoric acid aav.
Txoj hauv kev siv los ntawm WPA cov neeg tsim khoom feem ntau yog qhia Incoloy 825 raws li cov khoom siv hauv paus rau feem ntau ntawm cov txheej txheem cov cuab yeej, tom qab ntawd xaiv cov khoom hloov kho tshwj xeeb - feem ntau txheeb xyuas los ntawm kev tshuaj xyuas cov nroj tsuag corrosion lossis keeb kwm tsis ua ntej - rau Alloy 625 lossis lwm qhov siab -molybdenum alloy tsuas yog qhov chaw hauv cheeb tsam (5} nplua nuj fluoride{6}, ib sab fluoride luj tshib, los yog ib tug paub kub qhov chaw) thov nws.
Lub luag hauj lwm dab tsi ua fluoride thiab chloride paug ua si hauv kev xaiv cov khoom?
Fluoride thiab chloride qib - tsis yog P2O5 concentration lossis kub ib leeg xwb - feem ntau yog qhov kev txiav txim siab ntawm seb Incoloy 825 puas txaus lossis seb puas muaj cov hlau ntau dua, vim hais tias ob hom tuaj yeem ua rau hauv zos ua rau cov yeeb yaj kiab oxide uas tiv thaiv nickel alloys los ntawm acid nres.
Phosphate pob zeb qhov chaw sib txawv hauv cov ntsiab lus fluoride, thiab cov txheej txheem dej thiab cov kwj deg tuaj yeem qhia cov qib chloride sib txawv uas tsis yog ib txwm xav txog hauv cov nroj tsuag nominal tsim. Vim tias Incoloy 825 qhov kev tiv thaiv corrosion nyob ntawm qhov ruaj khov zaj duab xis, ua kom cov fluoride lossis chloride siab tshaj cov qib uas xav tau hauv cov khoom qub xaiv tuaj yeem ua rau qhov kev xav tau ceev ceev hauv cheeb tsam corrosion, txawm tias cov kua qaub ntau thiab qhov kub thiab txias nyob hauv ib txwm tsim txwv. Vim li no, kev xaiv cov khoom siv tau zoo thiab cov kev pabcuam kev ntseeg tau nyob rau hauv WPA cov nroj tsuag niaj hnub suav nrog kev kuaj daim coupon corrosion thiab kev tshuaj xyuas cov khoom noj ib ntus es tsis yog cia siab rau P2O5 concentration thiab kub ib leeg.
Yuav ua li cas Erosion -Corrosion los ntawm cov txheej txheem Slurry cuam tshuam rau tshav kub Exchanger Tube Life?
Erosion-corrosion los ntawm tshem tawm gypsum thiab pob zeb khib nyiab hauv WPA shortens tshav kub exchanger tube lub neej feem ntau nyob rau hauv siab - qhov chaw ceev - raj inlets, U- khoov, thiab baffle tiv tauj cov ntsiab lus - qhov twg txhua yam tshem tawm ntawm kev tiv thaiv nws oxide zaj duab xis nyob rau sab nraud ntawm kev tswj, {5} kev hloov kho cov yeeb yaj kiab tseem ceeb npaum li kev xaiv alloy rau ntev - lub sij hawm cia siab rau.
Khaws lub raj- sab nrawm nyob rau hauv cov khoom siv alloy qhov kev pom zoo rau slurry-cov kev pabcuam WPA, feem ntau zoo hauv qab cov kev txwv tshaj tawm siv rau cov dej huv, tsis yog- abrasive kua.
Siv inlet tube liners los yog ferrules ntawm lub raj nkag, qhov twg turbulence thiab impingement los ntawm inlet nozzle concentrate erosive hnav.
Tsim baffle txiav thiab sib nrug kom txo qis ncaj qha siab - nrawm nrawm ntawm slurry tiv thaiv cov phab ntsa ntawm cov baffle tiv tauj.
Saib xyuas thiab ua kom huv si ib ntus kom tshem tawm cov khib nyiab pov tseg, vim tias qhov chaw tso dej tuaj yeem tsim cov kab sib txawv aeration uas ua kom cov xeb hauv qab qhov tso nyiaj.
Dab tsi Vuam thiab Fabrication Practices Preserve Incoloy 825's Corrosion Resistance nyob rau hauv Thaum tshav kub kub Exchangers?
Kev khaws cia Incoloy 825's corrosion resistance los ntawm fabrication yuav tsum tsawg- cov khoom siv carbon puag thiab muab tub lim hlau, ua kom tiav cov pa roj carbon monoxide (suav nrog cov roj lim dej ntawm lub raj ID), thiab cov hlaws hlaws tag nrho ntxuav kom tshem tawm cov cua sov, vim tias ib qho ntawm cov lapses no tuaj yeem tsim ib cheeb tsam tsawg dua - tiv thaiv cheeb tsam uas dhau los ua qhov kev pabcuam thawj zaug.
Siv qhov sib txuam Incoloy 825 muab tub lim hlau (ERNiFeCr-1 / ENiCrMo-3 raws li siv tau) kom tsis txhob muaj qhov sib txuas nrog kev sib txawv corrosion ntau dua li lub hauv paus hlau.
Tshem tawm lub raj sab hauv nrog cov roj inert thaum lub sij hawm vuam los tiv thaiv oxidation (heat tint) ntawm cov txheej txheem -wetted nto, uas yog deb tshaj rau cov cheeb tsam corrosion dua li cov ntaub thaiv zoo weld hlau.
Pickle thiab passivate welds tom qab tsim kom tshem tawm cov cua sov thiab rov ua kom cov txheej txheem chromium oxide tsis sib xws thoob plaws tag nrho cov npoo ntub dej.
Tswj kev sib cuam tshuam qhov kub thiab txias kom txo tau lub sij hawm siv nyob rau hauv qhov kub thiab txias ntau yam, txo qhov kev pheej hmoo ntawm chromium carbide nag lossis daus ntawm cov ciam teb txawm tias Incoloy 825 cov ntsiab lus qis carbon thiab titanium stabilization twb muab zoo rhiab heev.
Tshawb xyuas cov welds ua tiav rau kev nkag mus rau tag nrho thiab kev ywj pheej los ntawm cov crevices lossis tsis muaj - ntawm - fusion defects, txij li cov qauv geometric no dhau los ua qhov chaw nyiam rau kev xeb tsis hais txog kev siv tshuaj lom neeg.
Yuav Ua Li Cas Cov Hluav Taws Xob Hluav Taws Xob Yuav Tsum Tsim Rau Lub Neej Ua Haujlwm Ntev hauv WPA?
Ntev ntev -WPA cov khoom siv hluav taws xob sib txuas ua ke cov kev xaiv cov hlau uas tsim nyog nrog cov yeeb yaj kiab zoo nkauj- sab nrawm, kev tiv thaiv corrosion txaus, cov khoom siv tau yooj yim rau kev tshuaj xyuas thiab ntxuav, thiab cov khoom siv hloov chaw (tubesheets, channel taub hau) tsim los kom tsis txhob muaj teeb meem galvanic thiab crevice qhov twg cov ntaub ntawv sib txawv.
Xaiv cov khoom siv raj (feem ntau Incoloy 825, nrog Alloy 625 nyob rau hauv cov cheeb tsam loj uas paub) raws li cov txheej txheem fluoride, chloride, thiab kub cov ntaub ntawv - tsis yog generic P2O5 concentration ib leeg.
Teem lub raj-sab nrawm nyob rau hauv qhov ntau pom zoo rau slurry-cov kabmob kev pabcuam kom sib npaug ntawm cov khoom siv hluav taws xob hloov hluav taws xob tiv thaiv kev yaig- kev pheej hmoo corrosion.
Qhia kom meej cov phab ntsa thickness corrosion txaus raws li cov nroj tsuag -tshwj xeeb corrosion xyuas keeb kwm es tsis yog generic default.
Tsim tubesheets thiab channel taub hau nrog cov ntaub ntawv sib xws los yog clad kom tsis txhob galvanic corrosion qhov twg lub raj alloy ua tau raws li cov khoom siv sib txawv.
Muab cov pob khoom txaus- rub tshem tawm thiab tshuaj xyuas, txij li kev tshuaj xyuas lub raj thiab tu lub sijhawm yog qhov tseem ceeb rau kev ntes cov tshuaj tiv thaiv hauv zos los yog yaig ua ntej nws ua rau xau.
Tsim kom muaj daim coupon no niaj hnub- kev sim thiab tshuaj xyuas cov kev pabcuam los taug qab tus nqi corrosion tiag tiag tiv thaiv qhov kev xav ntawm tus qauv tsim thiab ntes cov txheej txheem chemistry hloov ua ntej lawv ua rau qhov tsis tau npaj tseg.
Tus Nqi Tag Nrho Cov Tswv Cuab yog dab tsi rau Incoloy 825 vs Alternatives hauv WPA Service?
Txawm hais tias Incoloy 825 tus nqi ntau zaus ntau dua ib chav tsev loj dua 316L stainless hlau, nws feem ntau xa cov nqi qis ntawm cov tswv cuab hauv ntub dej - txheej txheem phosphoric acid kub exchanger kev pab cuam vim nws zam lub raj tsis tu ncua, tsis tau npaj tseg, thiab cov khoom hloov pauv uas 316L tau ntsib hauv qhov chaw no.
Kev sib piv tus nqi tseem ceeb yuav tsum suav nrog tsis yog tus nqi pib lub raj ntim khoom nkaus xwb tab sis lub sijhawm xav tau ntawm kev ua tsis tiav, tus nqi ntawm cov khoom lag luam uas tsis tau npaj tseg thaum txhua qhov tsis ua haujlwm, thiab cov nqi zog thiab pov tseg ntawm cov khoom hloov pauv. Hauv ntub dej - txheej txheem phosphoric acid, 316L exchangers feem ntau ntsib pitting lossis kev ntxhov siab- corrosion- cuam tshuam txog kev xau zoo nyob rau hauv ob peb xyoos ntawm kev pabcuam txuas ntxiv, thaum tsim thiab tsim Incoloy 825 exchangers feem ntau ua tiav kev pabcuam lub neej ntsuas hauv kaum xyoo lossis ntau dua nyob rau hauv tib lub sijhawm. Thaum cov kev zam no tsis ua haujlwm thiab cov nqi poob qis, suav nrog Incoloy 825 tus nqi khoom siv siab dua feem ntau tau rov qab tau ntau zaus dhau los ntawm kev sib pauv lub neej ua haujlwm, ua rau nws qhov kev xaiv muaj txiaj ntsig zoo rau feem ntau ntawm WPA cov khoom siv hluav taws xob txawm tias nws siab dua - tus nqi pem hauv ntej.
Cov lus nug nquag
