Yuav ua li cas xaiv Titanium Alloy (Qib 7 nrog Palladium vs. Qib 12 nrog Molybdenum) Hloov cov Phab Ntsa Thickness Rau Cov Cuab Yeej 10% Formic Acid ntawm Boiling Point?

Qhov kev lag luam yooj yim hauv kev xaiv alloy rau formic acid kev pabcuam
Concentrated formic acid (HCOOH, >5. Qib 2 titanium yog uniformly tawm tsam los ntawm boiling 10% formic acid ntawm tus nqi siab tshaj 0.5 hli ib xyoo thiab tsis pom zoo rau lub sij hawm ntev immersion rhaub dej tsis hais txog ntawm phab ntsa thickness. Ob lub titanium alloys feem ntau tau teev tseg rau ib puag ncig no. Qib 7 (Ti-0.15% Pd) thiab Qib 12 (Ti-0.3% Mo-0.8% Ni). Ob leeg nce corrosion kuj los ntawm kev sib cais - palladium ennobles saum npoo, molybdenum thiab npib tsib xee txhim kho cathodic kinetics. Kev xaiv ntawm cov alloys ncaj qha cuam tshuam rau phab ntsa tuab kom ua tiav qhov kev pabcuam lub neej, raws li tus nqi corrosion txawv ntawm qhov sib txawv ntawm 3-5 hauv cov kua qaub kua qaub. Ntxiv mus, txhua yam ntawm cov alloys muaj nws tus kheej tshwj xeeb cov cuab yeej thiab thermal conductivity uas txiav txim siab qhov tsawg kawg nkaus phab ntsa thickness rau kev tsim kho thiab hloov tshav kub. Qhov kev tshawb nrhiav no ntsuas qhov cuam tshuam ntawm kev xaiv alloy ntawm phab ntsa tuab uas xav tau rau 5-xyoo kev pabcuam lub neej hauv boiling 10% formic acid.

Corrosion Rates thiab Allowances: Muab xam cov nyhuv ntawm Mechanical Integrity
Cov txheej txheem corrosion rau Qib 7 thiab 12 yog qhov sib txawv hauv qhov kub ntawm 10% formic acid ntawm 1000C. Qib 7 yog tsim los ntawm palladium (0.12–0.25 wt.%) yaj hauv titanium matrix. Palladium yog cov hlau tsis zoo nrog lub siab hydrogen overpotential thiab nws hloov lub peev xwm corrosion ntawm titanium mus rau hauv cheeb tsam passive, txawm tias txo cov kua qaub. Kev ntsuam xyuas immersion ib ASTM G31 qhia tus nqi corrosion ntawm 0.02-0.05 mm/xyoo rau Qib 7 hauv boiling 10% formic acid. Qib 12 siv molybdenum thiab npib tsib xee los ua kom cov cathodic hydrogen evolution cov tshuaj tiv thaiv thiab tiv thaiv hydride txheej raug tso cai tsim. Nyob rau hauv tib qhov chaw nws corrosion tus nqi yog 0.10-0.15 hli nyob rau ib xyoos-txog peb zaug siab tshaj li qib 7. Nrog ib tug tsim lub neej ntawm 5 xyoo thiab ib tug 2x kev nyab xeeb yam ntawm corrosion nyiaj (piv txwv li cov phab ntsa yuav tsum muaj ob zaug ntawm qhov kev cia siab nkag mus rau qhov tob), qhov yuav tsum tau phab ntsa thickness purely rau corrosion pub yog: rau Qib 7, 0.05 mm} xyoo × 2; { rau Qib 12, 0.15 hli / xyoo × 5 xyoos × 2=1.5 hli. Yog li ntawd, los ntawm kev pom kev xeb nkaus xwb, Qib 7 tuaj yeem siv nrog phab ntsa thickness tsawg li 1.0 hli (ntxiv rau 0.5 hli rau cov khoom siv dag zog) thaum Qib 12 yuav tsum muaj qhov tsawg kawg nkaus ntawm 2.0 hli los muab cov npoo zoo tib yam corrosion. Tab sis txhua yam yam ntxwv thiab thermal conductivity ntxiv lwm yam kev txwv.

Thermal Performance Impact: Thermal Conductivity thiab Fais Fab Derating
Titanium alloys ntawm 100℃muaj qhov zoo sib xws, tab sis tseem ceeb, thermal conductivity, nrog qib 7 (yuav luag ntshiab titanium nrog palladium) ntawm k ≈ 17.5 W / m·K thiab qib 12 (molybdenum nrog nickel) ntawm k ≈ 14.5 W / m 7% (≈ 14.5 W / m·K). Muab tib lub phab ntsa tuab thiab lub zog ntom ntom, Qib 12 sheath yuav ua haujlwm kub dua li Qib 7 sheath. Qib 12 lub rhaub muaj 2.0 hli phab ntsa tuab thiab 17% qhov hluav taws xob kub poob ntau dua li Qib 7 lub rhaub nrog 1.0 hli phab ntsa raws li Fourier qhov sib npaug rau cylindrical conduction. Qhov tseem ceeb tshaj, qhov tsawg kawg nkaus phab ntsa thickness rau kev tsim khoom tsis yog tib yam. Qib 12 muaj lub zog zoo dua (yield zog ≈ 480 MPa vs. Qib 7 ntawm ≈ 275 MPa), tab sis tsawg dua ductility (elongation ≈ 15% vs . 20%). Qib 12 tubing tuaj yeem kos rau ntawm phab ntsa nyias (yam tsawg kawg 0.7 mm) dua qib 7 (yam tsawg 0.9 mm) vim tias lub zog siab dua tso cai rau lub raj tuaj yeem tiv taus qhov kev ntxhov siab ntawm kev kos duab yam tsis muaj ripping. Txawm li cas los xij, ob qho tib si no muaj nyob rau hauv welded raj mus txog 0.5 hli. Qhov kev txwv tsis pub muaj peev xwm tsim tau rau hauv U- khoov lossis cov duab bespoke: Qib 12 yuav tsum muaj ntau dua khoov radii (yam tsawg kawg 3 × OD) dua qib 7 (2.5 × OD) vim nws tsis tshua muaj ductile. Qhov no cuam tshuam cov cua sov geometry thiab tej zaum yuav xav tau ib phab ntsa tuab yog tias yuav tsum tau khoov nruj.

Kev lag luam- tawm kev sib txuas: phab ntsa thickness xaiv matrix rau 5-xyoo kev pabcuam
Cov nram qab no matrix piv rau Qib 7 thiab Qib 12 rau lub titanium immersion rhaub nyob rau hauv boiling 10% formic acid (100 degree, atmospheric siab) nrog rau ib tug xav tau kev pab lub neej ntawm 5 xyoo raws li ib tug raug lub zog ceev ntawm 2.5 W / cm².

Parameter Qib 7 (Ti-Pd) Qib 12 (Ti-Mo-Ni) Engineering Implication
Corrosion rate nyob rau hauv boiling 10% formic acid 0.02 - 0.05 mm / xyoo 0.10 - 0.15 mm / xyoo Rau Qib 7 nws yog tsim nyog los muab 0.5 mm corrosion pub rau 5 xyoo Rau Qib 12 yuav tsum tau muab 1.5 mm.
Qhov tsawg kawg nkaus corrosion raws phab ntsa rau 5 xyoo lub neej (2x yam ntawm kev nyab xeeb) 1.0 hli (0.5 hli pub + 0.5 hli tuav) 2.0 hli (1.5 hli pub + 0.5 hli tuav) Qib 7 tuaj yeem nyias- phab ntsa tsim Qib 12 yuav tsum tuab- phab ntsa
Thermal conductivity (k) @ 100℃17.5 W / m K 14.5 W / m KG qib 12 khiav 17% kub dua rau cov phab ntsa muab, uas ntxiv rau tus nqi corrosion.
Pom zoo phab ntsa thickness rau 5 xyoo kev pab cuam (tsim sib npaug) 1.0 mm – 1.2 mm 1.8 mm – 2.2 mm Qib 7 tso cai rau me me, ntau thermally npaum cov cua sov. Qib 12 xav tau cov phab ntsa tuab, xaim hluav taws xob tsawg.
U-tube heater khoov vojvoog muaj peev xwm2.5 × OD yam tsawg kawg nkaus 3.0 × OD yam tsawg kawg nkaus Qib 12 tej zaum yuav xav tau cov cua kub hnyiab loj dua lossis ncaj- raj tsim .
Tus nqi ntawm cov khoom siv txheeb ze (ib kg) 1.0 (lub hauv paus) 0.7 - 0.8 Qib 12 yog pheej yig dua rau ib chav tsev loj, tab sis cov phab ntsa tuab yuav tsum txo qis lossis tshem tawm cov nqi kom zoo dua.
Haum rau kev siv cov kua qaub uas yuav tsum tau ua kom nruj txo qisSuitable rau me ntsis txo lossis sib xyaw acids Yog tias koj xav tau boil 10% formic acid, qib 7 yog lwm txoj hauv kev zoo dua.
Tshaj li phab ntsa Engineering: Hydrogen Absorption thiab Weld Quality
Lwm qhov kev xav hauv kev siv cov formic acid yog hydrogen nqus. Lub palladium nyob rau qib 7 tso cai rau recombination ntawm atomic hydrogen rau hauv molecule H 2 uas tsis diffuse rau hauv titanium lattice. Yog li ntawd, txawm nyob rau hauv cathodic tej yam kev mob, Qib 7 muaj ib tug heev tsawg hydrogen uptake. Qib 12 yam tsis muaj cov hlau zoo ntxiv ua rau qee qhov kev nqus hydrogen thiab npib tsib xee-molybdenum theem muaj peev xwm tsim cov nkig hydrides nrog txuas txuas ntxiv. Rau qhov tuab -walled (2.0 mm) Qib 12 lub rhaub dej, hydrogen embrittlement tsis tau xav txog rau 5 xyoos, vim tias tus nqi corrosion tsawg txaus los txwv kev tsim hydrogen. Txawm li cas los xij, hauv zos corrosion los yog galvanic coupling ua rau Qib 12 yooj yim rau hydride cracking dua qib 7. Qhov kev ncaj ncees weld kuj txawv. Nrog kev tiv thaiv txaus, qib 7 welds yuav khaws kev tiv thaiv corrosion zoo ib yam li lub hauv paus hlau. Qib 12 welds tej zaum yuav raug rau qhov zoo tshaj plaws corrosion nyob rau hauv tshav kub cuam tshuam cheeb tsam vim kev sib cais ntawm molybdenum. Qib 12 xav tau tom qab-weld heat treatment tsis tsim nyog, tab sis pom zoo. Yog hais tias muaj ob peb welded pob qij txha nyob rau hauv lub cua sov (flanges, thermowells, thiab lwm yam) ces Qib 7 yog qhov kev xaiv ntau dua.

Xaus: Nyias- phab ntsa tsim tso cai nrog qib 7; tuab- phab ntsa tsim cuam tshuam nrog qib 12
Kev xaiv ntawm titanium alloy profoundly influences phab ntsa thickness xav tau kom sov 10% formic acid rau boiling point. Qib 7 (Ti-Pd) muaj qhov corrosion ntawm 0.02–0.05 mm / xyoo, nyab xeeb 5- xyoo kev pab cuam lub neej, thiab phab ntsa thickness ntawm 1.0–1.2 mm. Tus nqi corrosion ntawm qib 12 (Ti-Mo-Ni) yog 0.10-0.15 mm / xyoo; Yog li, phab ntsa thickness rau tib lub neej kev pab cuam yuav tsum yog 1.8-2.2 hli. Qib 7 qhov thermal conductivity txhawb kev hloov mus rau cov cua sov, thiab nws cov ductility zoo dua tso cai rau kev khoov kom nruj dua thiab ntau cov qauv siv cua sov. Qib 12 muab cov khoom siv qis dua rau ib kilogram tab sis cov phab ntsa tuab uas xav tau rau cov khoom siv offsets lossis negates ib qho txiaj ntsig zoo thiab qis thermal conductivity cuam tshuam rau kev siv hluav taws xob. Rau kev txhim kho tshiab qhov twg boiling 10% formic acid yuav tsum tau rhuab qhov pom zoo specification yog Qib 7 nrog 1.0-1.2 hli phab ntsa thickness. Qib 12 yuav tsum tau siv rau qhov tsis tshua muaj zog formic acid concentrations (tsawg dua 5 feem pua) los yog rau qhov kub thiab txias thaum lub zog thiab cov nqi qis dua tuaj yeem ua rau cov phab ntsa tuab. Thaum thov ib qho kev tsocai, qhia cov qib alloy thiab phab ntsa tuab los ntawm cov ntaub ntawv corrosion tus nqi muab los ntawm cov chaw tsim khoom, thiab yuav tsum tau ua pov thawj ntawm kev ua tau zoo ntawm cov hlau los ntawm kev sim immersion raws li NACE TM0169.