Thaum siv Titanium Hluav Taws Xob Hluav Taws Xob Hluav Taws Xob Hluav Taws Xob rau Boil 20% Hydrochloric Acid, Cov Acid Dissolved Oxygen Level Li Cas Hloov Qhov Ntsuas Kub Qhov Tseem Ceeb Li Cas?

Cov hlau feem ntau yog qhov hnyav heev hauv qhov kub ntawm 20% HCl ntawm qhov kub ntawm 105 degrees. Titanium feem ntau tsis pom zoo rau kev siv HCl vim tias muaj kev xeb sai sai. Txawm li cas los xij, lwm daim ntawv thov yuav tsum tau luv luv lossis tswj kev raug mob xws li titanium qhov chaw pickling kab lossis cov txheej txheem tshuaj tshwj xeeb. Nyob rau hauv cov kev txwv no, cov concentration ntawm cov pa yaj nyob rau hauv cov kua qaub los ua cov txheej txheem tseem ceeb hauv kev tsim seb titanium tuaj yeem tiv taus txawm tias lub sijhawm luv luv. Oxygen ua haujlwm raws li cathodic depolarizer thiab hloov lub peev xwm ntawm titanium nto mus rau thaj tsam passive. Qhov tseem ceeb pitting kub (CPT)- qhov kub siab tshaj uas ruaj khov pitting pib- nce ntau nrog cov concentration ntawm cov pa yaj. Titanium raug tawm tsam ntawm chav tsev kub hauv deaerated 20% HCl. Hauv 20% HCl ntawm 1 atm ib nrab siab ntawm oxygen CPT nce mus txog 80 degree, tseem qis dua kub, tab sis siab txaus rau qee qhov kev pabcuam kub tsawg.

Oxygen-Dependent Passivation Mechanism nyob rau hauv Hydrochloric Acid

Titanium yuav tsum muaj oxidizing huab cua los tswj nws cov yeeb yaj kiab TiO2 passive. Hydrochloric acid yog ib qho kev txo qis, thiab cov tshuaj chloride ions tawm tsam txhua yam oxide flaws. Cov pa oxygen hauv cov tshuaj hauv cov kua qaub muab cov oxidizing muaj peev xwm tsim nyog rau kev kho cov yeeb yaj kiab. Kev txo cov pa oxygen yog tshwm sim ntawm qhov chaw titanium: O 2 + 4H + + 4e - → 2H 2 O. Cov tshuaj tiv thaiv cathodic no ua rau muaj peev xwm ua rau saum npoo thiab yog li inhibits qhov kev sib cais ntawm titanium. Yog hais tias qhov concentration ntawm cov pa yaj nyob rau hauv qis qis mus rau qhov tseem ceeb, ces cov cathodic tam sim no vim qhov txo cov pa oxygen tsis tuaj yeem them nyiaj rau anodic tam sim no vim yog titanium dissolution. Qhov saum npoo tej zaum poob mus rau hauv cheeb tsam nquag thiab tsis sib xws corrosion lossis pitting yog pib. Qhov tseem ceeb pitting kub yog qhov kub ntawm qhov uas tus nqi ntawm cov zaj duab xis disintegration yog siab dua tus nqi ntawm cov pa pab repassivation ntawm ib tug muab oxygen concentration.

Quantitative Change of Critical Pitting Temperature with Dissolved Oxygen

CPT qhov tseem ceeb rau Qib 2 titanium hauv 20% HCl ntawm atmospheric siab yog muab hauv qab no los ntawm kev tswj xyuas:

Dissolved oxygen <0.5 ppm (deaerated, N2-purged) CPT <25℃. Titanium nyob rau hauv chav tsev kub - txhoj puab heev corrosion. Corrosion tus nqi 2-5 mm / xyoo. Tsis pom zoo rau tej kev pabcuam kub.

Dissolved oxygen ntawm 2–5 ppm (cua-saturated ntawm 1 atm, ib txwm qhib lub nkoj): CPT 45–50℃. Passive cwj pwm hauv qab 45 degree, corrosion tus nqi<0.1 mm/year. Pitting starts within hours at temperatures above 50 °C. Attack is quick and devastating at boiling (105°C).

CPT ntawm 60-65℃). Dissolved oxygen ntawm 10-15 ppm (oxygen-sparged ntawm 1 atm). Txais tau ntawm 60℃tab sis tsis yog thaum kub kub. Qhov tob ntawm pitting 0.5 hli tom qab 100 teev ntawm 65 degree.

Dissolved oxygen 30-40 ppm (oxygen 3 atm ib nrab siab, siab system). CPT 75-80 degree. Ntawm 75℃qhov saum npoo nyob twj ywm passive. 20% HCl ntawm 105oC (1 atm) Tseem kub kub

Dissolved oxygen >50 ppm (cov pa ntshiab hauv qab 5 atm, cov khoom siv tshwj xeeb): CPT 85-90℃. Tsis ncav cuag kub kub ntawm atmospheric siab tab sis mus txog nws. Yuav tsum muaj lub zog siab los tswj DO.

Cov txiaj ntsig zoo rau kev pabcuam hauv boiling 20% ​​hydrochloric acid

Qhov kub ntawm 20% HCl boiling ntawm atmospheric siab yog 105 degree. Txhua tus nqi ntawm cov pa oxygen yaj ntawm ib feem siab ntawm 1 atm tsis tuaj yeem nce CPT mus rau 105℃. 65℃yog qhov siab tshaj plaws CPT tau nrog oxygen-saturated acid ntawm 1 atm. Yog li ntawd, txawm hais tias tsis muaj oxygen sparging, kev siv qib 2 titanium rau boiling 20% ​​HCl yog qhov tsis tsim nyog. Lub siab ntawm cov pa ib feem siab siab dua 1 atm yuav xav tau lub nkoj siab uas tsis sib haum xeeb hauv lub xeev kub npau npau . 1. Boiling 20% ​​HCl: Tantalum, zirconium los yog qee qhov siab silicon cam khwb cia hlau.

Dissolved Oxygen Control rau Tsawg Kub HCl Kev Pabcuam

Qib 2 titanium nrog oxygen tswj tau qhia hauv cov lus hauv qab no rau HCl kev pabcuam hauv qab CPT.

HCl Concentration & Operating Temperature Yam tsawg kawg yuav tsum tau Dissolved OxygenMaximum Tso Cai Chloride Concentration Pom zoo ua haujlwm zoo
3 ppm (cua saturation) 40℃10% HCl20% Txheem qhib lub nkoj. Tsis muaj cov pa oxygen tshwj xeeb xav tau.
8 ppm (nruam cua sparging) 20% 15% HCl 50℃Tso cua sparger ze lub rhaub. Txhua lub lis piam DO checks
20% HCl @ 60℃15 ppm (yuav tsum tau sparging nrog oxygen) 20% Siv cov pa ntshiab huv. Pressurize nkoj mus rau 2 atm rau DO txij nkawm Pom zoo: titanium Qib 7.
20% HCl, 70℃C.Tsis muaj peev xwm ntawm 1 atm 20% Qib 2 tsis tsim nyog. Siv 3 atm ntawm oxygen sparging ntawm Qib 7.
Chlorides >25% Any concentration at >25°CNo benefit >25% Titanium Tsis pom zoo tsis hais txog cov pa.
Lwm txoj rau HCl Service Engineering Boiling

If you need to boil 20% HCl, use tantalum or zirconium heaters instead of titanium. Tantalum is passive even in deaerated acid and has a CPT >150℃hauv 20% HCl. Zirconium yog heev resistant rau boiling HCl nyob rau hauv tag nrho cov concentrations. Yog tias titanium xav tau vim nyiaj txiag, khiav haujlwm qis dua 50℃nrog kev txuas ntxiv ntawm cov pa oxygen thiab lees txais qhov txwv lub neej ntawm 6-12 lub hlis. Qib 7 titanium (palladium stabilized) muab 10-15℃nce nyob rau hauv CPT txheeb ze rau Qib 2 nyob rau hauv tib cov xwm txheej oxygen thiab txuas ntxiv qhov kub ntawm qhov siv tau txog li 75℃nrog oxygen sparging.

Ua ib qho kev qhia tshwj xeeb<

Yog tias koj tab tom xav txog titanium hluav taws xob cua sov raj rau ib qho kev pabcuam hydrochloric acid, thawj qhov uas yuav tsum tau ua yog txiav txim siab lossis txheeb xyuas cov qib oxygen yaj ntawm cov kua qaub. Nco ntsoov tias titanium tsis zoo li yuav ua rau lub neej ua haujlwm txaus siab rau cov ntawv thov tshaj 60℃tshwj tsis yog tias lub kaw lus raug thawb kom nce oxygen solubility . 20% HCl, ambient siab, boiling Tsis txhob qhia titanium. Xwb, thov quotes ntawm tantalum clad los yog zirconium rhaub. Yog tias cov txheej txheem tsuas yog cuam tshuam nrog kev kub nyhiab (xws li kev tu lub voj voog), xav txog lub tshuab hluav taws xob tshem tawm uas tuaj yeem raug tshem tawm ntawm cov kua qaub thaum lub sij hawm boiling. Tus kws tshaj lij, los ntawm kev muaj kev sib raug zoo ntawm cov pa oxygen thiab qhov tseem ceeb pitting kub, zam qhov kev poob qis ntawm kev xav tias titanium qhov kev tiv thaiv corrosion feem ntau siv rau kub, concentrated hydrochloric acid.