Rau Chav Dej-Rau-Titanium Tube Bundle Heater, Qhov Zoo Tshaj Plaws Phab Ntsa Thickness yog dab tsi kom tsis txhob muaj condensate-Induced Pitting Ntawm Chav Sab?
Tso lus
Hauv lub plhaub-thiab- raj kub exchangers los yog immersed bundle heaters qhov twg chav condenses nyob rau sab nraum ntawm titanium raj, lub condensate txheej yuav ua tau ib tug qhov chaw ntawm localized corrosion. Chav - sab pitting feem ntau tshwm sim los ntawm impurities concentrated nyob rau hauv cov yeeb yaj kiab condensate-oxygen, chlorides, los yog qis-molecular- hnyav organic acids los ntawm cov pa paug paug. Tsis zoo li cov kua dej (cov txheej txheem ua kua), lub chav sab muaj kev sib txuas ua ke thiab cov voj voog evaporation, uas ua rau cov kab mob hnyav ntawm lub raj nto. Phab ntsa thickness xaiv ncaj qha cuam tshuam ntev npaum li cas lub raj tiv thaiv qhov nkag mus. Txawm li cas los xij, nce thickness tshaj qhov zoo tshaj tus nqi muab txo qis rov qab thaum nce nqi khoom thiab thermal kuj. Qhov zoo tshaj plaws phab ntsa thickness sib npaug rau qhov pib tiv thaiv (phab ntsa tuab dua tiv thaiv los ntawm- phab ntsa nkag mus ntev dua) nrog cov qauv tsim tsim.
Mechanism ntawm Condensate -Induced Pitting ntawm Titanium
Thaum cov dej ntshiab condenses ntawm titanium raj ntawm 120-160 degree, lub condensate yog thawj zaug distilled dej nrog tsawg conductivity. Txawm li cas los xij, cov tshuab hluav taws xob feem ntau muaj cov khoom thauj los ntawm kev kho dej boiler -sodium phosphate, amines, lossis kab chlorides. Raws li condensation tshwm sim, tsis yog -volatile impurities sau nyob rau hauv nyias condensate zaj duab xis. Oxygen absorbed los ntawm hauv - leakage ntxiv accelerates cathodic cov tshuaj tiv thaiv. Lub titanium passive zaj duab xis tseem nyob ruaj khov nyob rau hauv ntshiab condensate. Tab sis thaum cov tshuaj chloride concentration nyob rau hauv zaj duab xis tshaj 100-200 ppm thiab lub zos pH poob (los ntawm hydrolysis ntawm titanium ions los yog los ntawm acid{12}} tsim impurities), pitting pib. Txhua lub qhov propagates ntawm tus nqi txiav txim los ntawm lub zos chemistry thiab tube kub. Thaum lub qhov dej nkag mus rau ntawm phab ntsa, chav dej nkag mus rau hauv cov kua sab, ua rau cov txheej txheem sib kis thiab lub tshuab cua sov tsis ua haujlwm.
Quantitative Relationship Ntawm Phab Ntsa Thickness thiab Pit Penetration Time
Kev sim kuaj simulating steam-sab condensate nrog 50 ppm Cl⁻, 100 ppb yaj oxygen, ntawm 130℃tube qhov kub thiab txias, tau tsim cov hauv qab no propagation tus nqi rau Qib 2 titanium:
Phab ntsa thickness ntawm 0.7 hli: Lub sijhawm pib lub sijhawm ntawm 500-800 teev. Qhov propagation tus nqi ntawm 0.03 hli ib teev ib zaug pib. Tag nrho lub sij hawm nkag mus rau 700-1,100 teev (1-1.5 lub hlis). Tsis haum rau qhov kev pabcuam ua haujlwm tsis tu ncua.
Phab ntsa thickness ntawm 1.0 mm: Lub sijhawm pib lub sijhawm ntawm 800-1,200 teev. Propagation tus nqi ntawm 0.025 mm / h. Tag nrho lub sijhawm nkag ntawm 1,200–1,600 teev (2–2.5 lub hlis). Marginal rau kev ua haujlwm raws caij nyoog.
Phab ntsa thickness ntawm 1.2 hli (tus qauv kev lag luam): Lub sijhawm pib lub sijhawm ntawm 1,000-1,500 teev. Propagation tus nqi ntawm 0.020 mm / h. Tag nrho lub sijhawm nkag ntawm 1,600–2,100 teev (2.5–3 lub hlis). Txaus siab rau chav huv huv nrog kev tshuaj xyuas peb lub hlis twg.
Phab ntsa thickness ntawm 1.5 mm: Lub sijhawm pib lub sijhawm ntawm 1,200-1,800 teev. Kev nthuav tawm tus nqi ntawm 0.018 hli / teev. Tag nrho lub sijhawm nkag ntawm 2,500–3,200 teev (4–5 lub hlis). Txaus siab rau kev ua haujlwm tas mus li.
Phab ntsa thickness ntawm 2.0 hli: Lub sijhawm pib lub sijhawm ntawm 1,500-2,200 teev. Propagation tus nqi ntawm 0.015 mm / h. Tag nrho lub sijhawm nkag ntawm 4,000-5,000 teev (6-8 lub hlis). Extended lub neej tab sis nce nqi thiab thermal kuj.
Optimal Phab Ntsa Thickness Xaiv Phau Ntawv Qhia
Cov lus hauv qab no muab cov txheej txheem kev txiav txim siab rau kev xaiv chav - sab titanium raj phab ntsa tuab raws li chav dej zoo, condensate chemistry, thiab lub sijhawm ua haujlwm xav tau:
| Steam Quality & Condensate Condition | Pom zoo Phab ntsa Thickness (mm) | Lub Sijhawm Cia Siab rau Thawj Kev Nkag Mus | Kev ua lag luam-Off & Rationale |
|---|---|---|---|
| High -purity chav (boiler nrog demineralized pub, tsis muaj nqa mus),<10 ppm Cl⁻ in condensate | 1.0 hli | 3,000-4,000 teev | Thinner phab ntsa txo cov nqi khoom thiab txhim kho cov cua sov hloov. Tsawg pitting pheej hmoo ua pov thawj tias qhov ntsuas qhov hnyav dua. |
| Standard industrial chav, qee zaus boiler nqa, 20-50 ppm Cl⁻ | 1.2 hli | 2,000–2,500 teev | Kev lag luam txheem thickness. Txais tau rau 1-xyoo kev ua haujlwm tas mus li nrog boiler dej tswj. |
| Cov pa tsis zoo, nquag nqa, 50-100 ppm Cl⁻, pH qis (5-6) los ntawm cov organic acids | 1.5 hli | 3,000-3,500 teev | Ntxiv thickness muab kev ruaj ntseg margin. Txais kev hloov hluav taws xob qis dua (nce thaj tsam ntawm 10-15%). |
| Aggressive condensate (cooling tower contamination, >100 ppm Cl⁻), ua haujlwm 24/7 | 2.0mm ib | 5,000–6,000 teev | Qhov siab tshaj qhov tsis kam. Tus nqi siab dua thiab cov pob khoom loj dua yuav tsum tau ua. |
| Kev pabcuam chav ua haujlwm nruab nrab (txhua hnub thermal cycling, lub sijhawm qhuav) | 1.5 hli | 2,000-2,500 teev (cov voj voog nrawm nrawm nrawm) | Cycling concentrates impurities sai dua. Thicker phab ntsa pom zoo txawm tias siv tsis sib xws. |
Engineering Beyond Phab Ntsa Thickness Ib leeg
Phab ntsa thickness tsis tiv thaiv qhov pib; nws tsuas yog ncua kev nkag mus. Txhawm rau txo qhov pib zaus, tswj cov chav dej kom zoo: tswj cov dej boiler dej chlorides qis dua 5 ppm, siv cov khoom siv hluav taws xob zoo, thiab saib xyuas cov condensate conductivity. Tube cov ntaub ntawv qib tseem ceeb: Qib 7 titanium (0.15% Pd) nce qhov tseem ceeb chloride concentration rau qhov pib ntawm 100 ppm txog 500 ppm, cia cov phab ntsa thinner (1.0 hli) kom ua tiav tib lub neej raws li 1.5 hli Qib 2. Lub raj xa mus rau qhov cuam tshuam; ntsug raj tso condensate sai, txo cov zaj duab xis thickness thiab impurity concentration piv rau kab rov tav raj. Thaum kawg, lub sij hawm ib ntus -kev tu sab (dej yaug los yog cov kua qaub me me) tshem tawm cov impurities thiab txuas lub qhov dej -dawb lub neej los ntawm ib qho ntawm 2–3.
Ua ib qho kev qhia tshwj xeeb
Thaum qhia txog chav dej - mus rau - cov kua titanium raj bundle rhaub, thov kom muaj kev ntsuam xyuas qhov purity xws li chlorides, oxygen, thiab pH. Rau cov tshuaj chloride qis dua 10 ppm, qhia Qib 2 titanium nrog 1.0-1.2 hli phab ntsa tuab. Rau qib chloride ntawm 20–50 ppm, qhia 1.5 mm Qib 2 lossis 1.0 mm Qib 7. Rau qib chloride siab tshaj 50 ppm, qhia Qib 7 nrog 1.2 hli phab ntsa thickness los yog xav txog kev ua kom huv huv chav dej. suav nrog hauv qhov kev qhia tshwj xeeb uas yuav tsum tau ua kom cov raj tsis muaj cov kab mob hlau ntog (kuaj ib qho ASTM A380) vim tias cov khoom siv hlau embedded ua raws li qhov chaw pib. Thaum lub sijhawm ua haujlwm, nruab ib lub condensate conductivity saib ntawm lub qhov hluav taws xob; nce siab tshaj 2 µS / cm qhia impurity nqa nqa yuav tsum tau hloov boiler. Los ntawm kev xaiv qhov zoo tshaj plaws phab ntsa thickness raws li condensate chemistry es tsis xav tias thicker yog ib txwm zoo dua, tus engineer tshuav nqi, thermal kev ua tau zoo, thiab tsis kam mus rau chav - sab pitting.
