316L stainless hlau immersion rhaub tau siv dav hauv cov txheej txheem qhib-kho cov txheej txheem dej, cov khoom siv roj ntsha ua ntej kev kho mob thiab cov dej tsis huv nruab nrab ntawm cov khoom siv. Feem ntau cov ntaub ntawv ntsuam xyuas cov ntaub ntawv tsom mus rau inorganic ion corrosion thaum underestimating microbial-tsav degradation. Nyob rau hauv qhov ntsuas kub uas tsim nyog, cov kab mob sulphate-txo cov kab mob colonize lub qhov kub thiab txias ntawm qhov chaw sov thiab tsim kom muaj qhov ntom ntom heterogeneous biofilm. Cov dej num metabolic ntawm cov kab mob ua kom cov pa oxygen yaj thiab tsim cov hydrogen sulfide. Lub biofilm tsim cov anaerobic micro-zones hauv zos, thiab cov khoom siv sulfide rhuav tshem chromium-nplua nuj passive zaj duab xis, ua rau sulphidic pitting corrosion. Tus qauv abiotic laboratory corrosion daim coupons tsis tuaj yeem rov ua dua qhov kev tswj hwm kev ua tsis zoo no.
Thaum cov khoom noj khoom haus muaj nyob hauv cov txheej txheem dej, cov kab mob ua rau cov cua sov sab nrauv phab ntsa thiab tso tawm cov tshuaj polymeric extracellular los ua biofilm matrix. Nyob rau hauv cov txheej txheem biofilm, oxygen yog tag nrho depleted. Sulphate-txo cov kab mob hloov cov yaj sulfate ions rau hauv hydrogen sulfide. Sulphide penetrates passive zaj duab xis thiab reacts nrog hlau matrix los tsim cov hlau tsis ruaj tsis khov-sulphide compounds. Cov khoom siv sulfide no yog cov ntxeem tau thiab tsis tuaj yeem ua cov txheej tiv thaiv. Galvanic micro-cells tsim ntawm biofilm-them anodic zones thiab biofilm-dawb cathodic hlau nto. Pitting pib hauv qab biofilm thiab nthuav mus rau sab hauv. Txawm tias tom qab ib nrab biofilm poob rau hauv cov kua dej shear kev nyuaj siab, residual sulphide deposits ua kom muaj kev tiv thaiv hauv zos.
Nyob rau lub sijhawm ua haujlwm thaum ntxov, slimy dark-coloured biofilm thaj ua rau thaj ua rau pom ntawm daim ntaub. Cov neeg ua haujlwm feem ntau tshem tawm cov slime saum npoo thiab xav txog lub rhaub kom ua haujlwm ib txwm. Corrosion pits tseem muab zais hauv qab qhov chaw biofilm qub. Nrog lub sij hawm khiav accumulating, pits merge thiab txo phab ntsa thickness. Thaum kawg sheath perforation tshwm sim, txheej txheem ua kua invades cua sov ntsiab thiab ua rau cov khoom kaw. Kev soj ntsuam tom qab tsis ua haujlwm feem ntau yuam kev sulphidic biofilm pitting raws li cov tshuaj chloride-tsav corrosion zoo tib yam.
Kev ua haujlwm zoo tiv thaiv kev tswj xyuas biofilm-originated sulphidic corrosion. Ua kom zoo dej ua ntej kev kho mob kom txo tau cov organic nutrient loading. Siv sij hawm biocide dosing cycles txhawm rau txo qis microbial reproduction. Txhim kho cov dej turbulence los cuam tshuam kev ruaj khov biofilm txuas. Siv ultrasonic thickness scanning lub hom phiaj biofilm-ntim qis-flow aav nyob rau hauv kev saib xyuas ua hauj lwm.
表格
| Cua sov hom | Biofilm-Mediated Sulfidic Corrosion Risk | Core Degradation Mechanism | Early-stage Diagnostic Feature | Qhov Tseem Ceeb Mitigation Engineering Measure |
|---|---|---|---|---|
| 316L Stainless hlau | Siab | Sulphate-txo cov kab mob tsim anaerobic biofilm; metabolic hydrogen sulphide rhuav tshem cov zaj duab xis passive thiab induces subsurface pitting | Tsaus slimy biofilm thaj ua rau thaj; pits tseem nyob tom qab tshem tawm biofilm | Txo cov zaub mov organic; periodic biocide kev kho mob; txhim khu kev khiav turbulence; Local thickness tshuaj xyuas |
| Titanium | Nruab nrab | Biofilm txuas tshwm sim; tuab TiO₂ txheej ib feem tiv thaiv sulphide nres, tsis tau ntev ntev tseem ua rau muaj kev pheej hmoo pitting | Uneven tsaus discoloration ntawm sheath nto | Tsis tu ncua tshuaj ntxuav kom tshem tawm cov fouling lom |
| Fused Quartz | Tsis tsim nyog | Inert silica tsis tuaj yeem ua cov tshuaj tiv thaiv electrochemical; tsuas yog organic biological fouling accumulates | Nyias nplaum biofilm residues ntawm lub raj nto | Periodic oxidative tu txheej txheem |
| PFA-Jacketed | Tsis tsim nyog | Non-adhesive fluoropolymer txwv kev ruaj khov biofilm anchoring; tsis muaj kev pheej hmoo corrosion ntawm substrate | Patchy biological slime ntawm lub tsho sab nrauv | Routine circulating flushing thiab tu |
Xaus:Chloride concentration ib leeg tsis tuaj yeem kwv yees lub neej kev pab cuam ntawm 316L cov cua sov hauv cov dej tsis huv. Biofilm-generated sulphide tsim kev ywj pheej corrosion. Kev tswj cov khoom noj khoom haus thiab kev tswj cov fouling lom yog cov tswv yim tiv thaiv tseem ceeb rau kev qhib cov txheej txheem dej.
