Rau Qib 2 Titanium Heater Tube raug rau 500 ppm Hydrogen Sulfide (H₂S) hauv 2% NaCl ntawm 60 degree, Cov Sulfide Ion Hloov Cov Zaj Duab Xis Los Ntawm TiO₂ rau TiS li cas thiab nce tus nqi Corrosion ntawm 0.02 txog 0.30 mm / xyoo?
Tso lus
Cov zaj duab xis passive ntawm Qib 2 titanium hauv 2% NaCl ntawm 60℃nrog 500 ppm H2S hloov ntawm TiO2 mus rau titanium sulfide (TiS). TiS txheej yog ib qho ntxeem tau, tsis yog - txheej tiv thaiv thiab conductive. Corrosion npaum li cas ntawm 0.01-0.03 mm / xyoo (tsis H 2 S) txog 0.20-0.50 mm / xyoo. Qhov qhib Circuit Court muaj peev xwm hloov ntawm +0.1 V rau −0.4 V (vs. Ag/AgCl). Ti + 2H2S→TiS2 + 2H2 Titanium dissolves nquag.
Mechanism ntawm Sulfide-Induced Depassivation
Sulfide ions yog adsorbed rau ntawm titanium nto thiab hnov mob nrog oxide zaj duab xis: TiO2 + 2H2S → TiS2 + 2H2O. Cov txheej sulfide tsis tiv thaiv cov hlau. Corrosion yog uniform, tsis muaj pitting sau tseg.
Quantitative Corrosion Rate ua haujlwm ntawm H2S Concentration
H2S Cov Ntsiab Lus (ppm) Corrosion Rate (mm/yr)Ntoo Zaj Duab Xis 0.01-0.03 TiO2 0.03-0.06Mixed 50 0.06-0.12 Mixed 100 0.10-0.20 TiS 500 0.20-0.40 TiS 1,000 0.30-0.60 TiS Sulfide Tolerance Guide
H₂S Concentration (ppm) Pom Zoo Qib Kev Ntsuas Corrosion Rate (mm/xyoo)
<50 Grade 2 <0.10 50-200 Grade 7 0.05-0.15 200-500 Grade 7 plus cathodic protection 0.10-0.25 >500 PTFE-coated<0.01
Kev sau ntawv zoo - qhia meej meej
Avoid Grade 2 titanium at concentrations >50 ppm H2S muaj cov kua qaub. Siv titanium rhaub (Qib 7) los yog PTFE coated. Tus engineer siv qhov kev paub ntawm qhov depassivation ntawm sulfides los xaiv cov ntaub ntawv zoo.
