Nyob rau hauv khib nyiab incinerator ntub Scrubbers tuav Hydrochloric Acid Vapors, Qhov twg Titanium Alloy (Ti-0.15Pd vs Ti-0.3Mo-0.8Ni) Muab Superior Crevice Corrosion Resistance?

Cov khib nyiab khib nyiab ntub dej zaum ntawm qhov sib cuam tshuam ntawm - kub combustion gases thiab corrosive kua nqus tshuab. Cov vapors ntawm hydrochloric acid los ntawm hlawv cov chlorinated plastics thiab lwm yam pov tseg yog condensed mus rau ib tug scrubber cawv ntawm 5-15% HCl ntawm 60-80oC. Titanium alloys feem ntau raug xaiv rau cov khoom siv hauv tsev xws li tshuaj tsuag lub taub hau, pos huab eliminators, thiab reheater raj. Hom tsis ua hauj lwm feem ntau yog crevice corrosion ntawm tube-rau-tubesheet junctions, nyob rau hauv gaskets thiab nyob rau hauv cov khoom deposits. Muaj ob lub titanium alloys uas yog contenders rau qhov kev pab no, Qib 7 (Ti-0.15Pd) thiab Qib 12 (Ti-0.3Mo-0.8Ni) thiab lawv muaj ntau txoj kev ntawm crevice corrosion kuj. Daim ntawv no ntsuas qhov ua tau zoo ntawm cov alloys nyob rau hauv hydrochloric acid scrubber tej yam kev mob thiab txiav txim siab uas alloy muab kev tiv thaiv zoo dua tiv thaiv crevice nres.

Mechanism ntawm Crevice Corrosion hauv HCl Scrubbers
Nyob rau hauv ib tug crevice - feem ntau yog ib tug 0.1-0.5 hli qhov sib txawv ntawm ib tug titanium raj thiab ib tug PTFE gasket los yog nruab nrab ntawm ib lub raj thiab ib tug dov raj ntawv - cov chemistry yog txawv heev los ntawm tej kua nplaum. Cathodic txheej txheem sai sai tso pa oxygen nyob rau hauv lub crevice. Thaum tsis muaj oxygen titanium yog anodically yaj nrog kev tsim ntawm Ti³⁺ thiab Ti⁴⁺ ions uas hydrolyze rau HCl tsis tu ncua txo cov pH crevice. Hauv ib lub tshuab ntxhua khaub ncaws nrog 10% HCl, pH tuaj yeem qis dua 0 ntawm pH ntawm kwv yees li 0.5. Kev sib xyaw ua ke ntawm cov ntsiab lus chloride siab, pH tsawg thiab txwv kev thauj mus los hauv ib puag ncig autocatalytic uas ua rau kom nrawm nrawm nrawm thaum nws tau pib.

Qhov tsis kam ntawm ib qho hlau rau qhov kev tawm tsam no yog txhais los ntawm qhov tseem ceeb ntawm qhov kub thiab txias (CCT) thiab qhov muaj peev xwm loj heev (CCP). CCT yog qhov kub siab tshaj plaws ntawm qhov kev sib sau ua ke (ASTM G78) tuaj yeem tso rau hauv 72 teev yam tsis muaj kev tawm tsam tshwm sim. CCP yog qhov pib dhau qhov uas tsis muaj qhov pib tshwm sim ntawm qhov kub thiab txias ntawm cov tshuaj chloride.

Qib 7: Palladium Stabilized Passivation
Qib 7 titanium muaj 0.12-0.25% palladium, cov hlau noble uas yog qhov zoo tshaj plaws cathodic site rau hydrogen evolution thiab txo cov pa oxygen. Nyob rau hauv cov pa oxygen- tshaib plab crevice ib puag ncig, palladium catalyzes txo cov hydrogen ions (2H+ + 2e- → H2) ntawm qis dua qhov muaj peev xwm tshaj li titanium nws tus kheej. Cov tshuaj tiv thaiv cathodic no kho lub peev xwm crevice nyob rau hauv cov kev taw qhia noble thiab li no pab txhawb nqa cov zaj duab xis passive txawm nyob rau hauv qis pH, oxygen starved tej yam kev mob.

Qib 7 muaj CCT nyob rau hauv 10% HCl ntawm 70 deg C ntawm txog 65 deg C - piv txwv li crevice nres tsis pib qis dua 65 deg C nyob rau hauv cov qauv kev xeem. Crevice nres yog thaum 100-200 teev ntawm 75 degree. Qib 7 yog nyob ntawm lossis qis dua nws CCT rau lub tshuab ntxhua khaub ncaws khiav ntawm 60-70 degree, muab qhov me me tab sis ua haujlwm ruaj ntseg.

Qib 12: Mo-Ni Power-Up
Qib 12 titanium muaj 0.2-0.4% molybdenum thiab 0.6-0.9% nickel. Nyob rau hauv sib piv rau palladium, uas hloov cov txheej txheem cathodic, molybdenum yog enriched nyob rau hauv passive zaj duab xis li molybdate hom (MoO₄²⁻) uas impede chloride ion nkag mus thiab txo tus nqi ntawm anodic dissolution. Nickel ua rau kom muaj kev ruaj ntseg ntawm cov yeeb yaj kiab passive hauv kev txo cov kua qaub thiab pab rov ua dua tom qab kev puas tsuaj rau cov yeeb yaj kiab. Qhov kev sib xyaw ua ke no ua rau muaj qhov ua tau zoo dua qub rau cov yeeb yaj kiab tiv thaiv kev puas tsuaj txawm tias nyob rau hauv cov tshuaj lom neeg nruj heev.

Qib 12 muaj CCT ntawm ib ncig ntawm 80℃hauv 10% HCl ntawm 70 degree, uas yog ntau dua li Qib 7. Qib 12 qhia tau hais tias me ntsis crevice nres tom qab 500 teev ntawm 85 degree. Qhov kev ua tau zoo dua qub yog los ntawm qhov tseeb tias molybdenum-nickel ntxiv ua rau muaj kev ruaj ntseg ntawm cov zaj duab xis passive, es tsis yog hlau hlau catalysis, uas tuaj yeem cuam tshuam thaum hydrogen evolution yog cov tshuaj tiv thaiv cathodic predominant.

Incinerator Scrubber Performance Comparison
Cov ntaub ntawv los ntawm cov khib nyiab incinerator scrubbers khiav ntawm 65-70℃nrog 8-12% HCl pom qhov sib txawv ntawm ob lub alloys. Qib 7 cov raj raug tshem tawm tom qab 5 xyoos kev pabcuam qhia pom qhov tob tob tob (0.1-0.3 hli) ntawm cov pob qij txha thiab hauv qab gaskets. Qee qhov kev teeb tsa qib 7 tau ntsib los ntawm kev sib tsoo ntawm 7-8 xyoo. Raws li cov xwm txheej zoo ib yam, Qib 12 cov hlab ntsha tsis pom muaj qhov cuam tshuam loj heev tom qab 5 xyoos, thiab tsuas yog qhov tsawg kawg nkaus etching (0.05 hli) tom qab 8-10 xyoo.

Qhov kom zoo dua ntawm Qib 12 yog qhov tshwj xeeb tshaj yog nyob rau hauv cov tshuab ntxhua khaub ncaws uas muaj teeb meem kub . 75-80℃raug rau lub sij hawm ntev ua rau muaj kev tawm tsam hauv Qib 7 crevices uas yuav loj hlob mus rau 0.5 mm qhov tob hauv lub hlis. Qib 12 kuj tsis cuam tshuam rau qhov kub thiab txias.

Incinerator Scrubber Titanium Alloy Daim Ntawv Thov Matrix
Scrubber Operating Condition HCl Concentration (pom zoo Alloy Temperature RangeAnticipated Crevice-Free Life
Kev ua haujlwm sib law liag, ruaj khov kub 5-10% 55-65℃Qib 7 5-7 xyoo
Kev ua haujlwm tsis tu ncua, qhov kub thiab txias 10-15% 55-65℃Qib 12 8-10 xyoo
Kev khiav hauj lwm sib txawv Kub ntxhov siab txog 75℃5 txog 10% 60 txog 75℃Qib 12 6 txog 8 xyoo
High chlorine pov tseg, feem ntau excursions10-15% 65-80℃Qib 12 (min) 5-7 xyoo
Txhua qhov kev pabcuam uas muaj cov khoom ntim hnyav hnyav tam sim noAny Qeb 12 Cov nyiaj tso cia ua rau muaj kev pheej hmoo siab; nyiam qib 12
Tsim tshiab, 10 xyoo tsim lub neej 5-15% 60-70℃Qib 12 10+ xyoo
Xaus ntawm Incinerator Scrubber Specification
Nyob rau hauv khib nyiab incinerator ntub scrubbers qhov twg hydrochloric acid vapors yuav tsum nyob rau ntawm 60-80 degree, Qib 12 titanium (Ti-0.3Mo-}0.8Ni) yog qhov zoo dua rau Qib 7 (Ti-}0.15Pd ntawm kev tiv thaiv corrosion. Cov anodic inhibition los ntawm molybdenum-nickel ntxiv txhim kho kev ruaj ntseg ntawm cov yeeb yaj kiab passive thiab ua rau qhov kub siab tshaj plaws ntawm qhov ntsuas kub li ntawm 15℃siab dua Qib 7. Cov kev pab cuam scrubber yog nyob ntawm 65-70℃nrog 10% HCl. Qib 12 yuav muab 8-10 xyoo ntawm kev pabcuam pub dawb tab sis Qib 7 yuav pib tawm tsam tom qab 5-7 xyoo. Qib 12: Cov alloy nyiam rau kev teeb tsa tshiab lossis kev hloov pauv uas yuav tsum muaj 10-xyoo lub neej, tab sis raug nqi me ntsis (kwv yees li 15-20% ntau dua Qib 7). Qib 7 tseem tsim nyog rau cov khoom siv hluav taws xob qis qis (55-65 degree) lossis yog tias tus nqi pib thawj zaug yog qhov kev txwv tseem ceeb, tab sis Qib 12 yuav tsum tau teev tseg qhov twg qhov kub hnyiab tuaj yeem siab dua 65℃lossis qhov twg cov ntsiab lus chloride tshaj 10%. Thaum koj yuav, thov rau ASTM B338 Qib 12 cov hlab nrog cov npoo thiab welded (tsis dov) raj-rau-tubesheet pob qij txha txhawm rau tshem tawm cov crevices ntawm cov raj-rau-tubesheet sib txuas thiab pab ua kom lub neej ntev.