PTFE vs Stainless hlau cua sov Tubes: Leej twg muaj sia nyob hauv Acid Baths?

Stainless hlau cua sov tube nyob rau hauv ib da dej hydrochloric acid yuav pit thiab poob nyob rau hauv ib lub hlis. Cov nroj tsuag hloov nws thiab ces tib yam tshwm sim dua. PTFE cua sov raj yog tshuaj inert, tab sis lawv puas tsim nyog tus nqi ntxiv? Cia peb saib yuav ua li cas ob qho khoom ua haujlwm thaum raug mob hnyav.
Cov raj cua sov yog lub hauv paus ntawm kev ua haujlwm hauv cov khw plating, semiconductor cov rooj zaum ntub dej thiab cov kab ua tshuaj lom neeg-submerged hauv cov tso tsheb hlau luam uas sib xyaw cov kua qaub, chlorides lossis muaj zog alkalis hnub dhau hnub. Kev xaiv ntawm stainless hlau (feem ntau SUS304 los yog ntau ruaj SUS316L) los yog PTFE (polytetrafluoroethylene, Teflon) tsis yog ib qho teeb meem ntawm tus nqi. Nws yog qhov kev txiav txim siab uas cuam tshuam rau lub neej ntawm lub rhaub dej, qhov huv ntawm chav da dej thiab tus nqi ntawm lub sijhawm poob qis uas cov nroj tsuag yuav noj.
Stainless hlau yog corrosion resistant vim hais tias nws muaj ib tug nyias txheej ntawm chromium oxide uas tshwm sim nyob rau saum npoo. Cov txheej tsis pom no, tsuas yog ob peb nanometers tuab, feem ntau tiv thaiv cov hlau, chromium thiab npib tsib xee hauv qab ntawm oxygen thiab dej. Cov txheej yog ruaj khov nyob rau hauv me me, nruab nrab dej los yog dilute alkalis. Ntxiv hydrochloric acid, sulfuric acid los yog siab chloride concentrations thiab chemistry hloov. Localized anodic sites yog tsim los ntawm kev nkag ntawm chloride ions rau hauv oxide txheej ntawm me me flaws. Qhov tshwm sim yog pitting corrosion. Cov qhov me me uas loj hlob sai vim tias lub qhov dej sab hauv yuav ua rau acidic thiab txhoj puab heev. SUS304 ua tsis tau sai tshaj plaws. SUS316L muaj ib qho ntxiv 2-3% molybdenum uas ua rau qeeb qeeb tab sis tsis nres. Crevice corrosion – qab mounting brackets los yog nyob rau hauv qis -flow cheeb tsam – kuj speeds puas. Thaum lub qhov dej tawg los ntawm lub raj phab ntsa, lub rhaub dej ntws tawm, lub da dej ua paug rau hauv pem teb, thiab kev tsim khoom nres. Cov hlau tsis muaj hlau tso tawm cov kab hlau ions-hlau, chromium, npib tsib xee- mus rau hauv cov tshuaj txawm tias ua ntej pom tseeb tawg. Cov ions no tuaj yeem tshwm sim ua ntej pom pitting hauv qhov chaw-ib -billion theem, thiab tuaj yeem cuam tshuam cov txheej txheem rhiab xws li electroless nickel plating lossis high-purity chemical synthesis.

PTFE ua nws tag nrho lwm txoj kev. Nws xav tau tsis muaj txheej txheej passive los tswj vim nws tsis xav tau. Nws muaj ib tug qauv molecular nrog ib tug carbon caj qaum tag nrho insulated los ntawm fluorine atoms. C-F daim ntawv cog lus yog ib qho muaj zog tshaj plaws nyob rau hauv cov organic chemistry thiab qhov chaw yog li ntawd tsis tshua muaj resistant rau electron hloov los yog tshuaj tua kab mob. Cov kua qaub, cov hauv paus, oxidizers lossis cov kuab tshuaj organic ntawm cov txheej txheem kub ib txwm tsis tuaj yeem tawg cov ntawv cog lus. Tsis muaj pitting, tsis muaj crevice corrosion thiab tsis muaj thinning. Tsib xyoos tom qab thiab lub raj yog zoo li du thiab chemically tib yam li nws nyob rau hnub ib. PTFE tsis muaj hlau, yog li tsis muaj hlau ions leaching rau hauv da dej. Qhov inertness no tsis yog khoom kim heev-nws yog ib qho kev xav tau rau cov khoom siv hluav taws xob semiconductor, kev tsim tshuaj API los yog cov txheej txheem twg txawm tias 10 ppb ntawm nickel yuav ua rau puas tsuaj.
Cov kua ntses zais cia yog qhov pheej hmoo ntawm kev kis kab mob. Lub raj stainless hlau yuav zoo zoo thaum lub sij hawm soj ntsuam, tab sis tseem yuav muab tawm ions uas cuam tshuam xim, ci ntsa iab lossis purity ntawm cov khoom kawg. Cog engineers nquag tsuas kawm txog qhov teeb meem tom qab downstream tsis zoo. PTFE tshem tawm qhov sib txawv ntawd tag nrho. Nws kuj tseem muaj qhov tsis yog- nplaum nplaum uas txo qhov kev ntsuas thiab fouling kom cov cua sov- hloov kev ua haujlwm tsis zoo nyob rau lub sijhawm raws li cov deposits tsim rau ntawm cov hlau, tab sis nyob twj ywm.
Tam sim no saib tag nrho cov nqi ntawm cov tswv cuab. Lub tsho fluoropolymer thiab tsim sab hauv ntawm PTFE immersion rhaub yog qhov nyuaj rau kev tsim khoom, yog li tus nqi yuav khoom siab dua -feem ntau 2 mus rau 4 npaug ntawm qhov sib piv stainless - khoom siv hlau. Tab sis nrog kev pabcuam nruj, cov duab hloov pauv. Stainless-cov kav hlau siv hauv 10–20 % HCl lossis ferric chloride da dej feem ntau yog hloov tom qab 3 txog 12 lub hlis ntawm kev siv. Txhua qhov kev hloov pauv- tawm yuav tsum tau tshem lub tank, txias da dej, muab nws rov qab rau hauv thiab rov pib dua - teev lossis hnub poob khoom lag luam. Hloov chaw ua haujlwm, qhov chaw thiab lub sijhawm poob yuav yooj yim raug nqi ntau dua li thawj tus nqi sib txawv hauv tsib xyoos. PTFE tubing feem ntau kav li 5 mus rau 10 xyoo nrog rau kev kuaj hluav taws xob ib ntus xwb. Ntxiv rau hauv cov tshuaj pheej yig dua saum toj kawg nkaus -ups (tsis muaj hlau- cov tshuaj tiv thaiv sab nraud) thiab txo cov seem seem los ntawm kev sib kis, thiab kev txuag nyiaj ntau ntxiv.
Tsuas yog thaj chaw uas stainless hlau muaj ntug yog qhov kub thiab txias. Yog tias qhov kev tsim kho tshuab tso cai, SUS304 thiab SUS316L tuaj yeem siv tsis tu ncua saum 400 degree. Qhov ua tau zoo tshaj plaws rau cov khoom siv cua sov yog 200-230deg C hauv PTFE nyob ntawm qhov siab thiab qib. Luckily feem ntau cov tshuaj da dej, txawm tias rau etching, anodizing, tu lossis electroless plating ua haujlwm zoo hauv qab 100℃thiab txawm tias cov txheej txheem kub kub tsis tshua muaj siab tshaj 180℃ntawm qhov chaw ntawm lub rhaub. PTFE tsuas yog nyob hauv lub hnab ntawv xwb.
Cov lus qhia hauv kev xyaum tsuas yog kom phim cov ntaub ntawv rau chemistry. Stainless hlau, tshwj xeeb tshaj yog SUS316L, yog qhov kev xaiv pheej yig rau cov dej ntshiab, cov tshuaj ntxuav me me los yog tsis yog - cov tshuaj halogenated. Nws hloov cov cua sov zoo dua, nws yog mechanically muaj zog thiab nws yog pheej yig dua pib nrog. Tab sis thaum da dej muaj cov ntxhia acids, chlorides, fluorides, los yog xav tau qhov chaw -ib -billion purity, PTFE yog qhov kev nyab xeeb, ntev dua - lwm txoj kev kav ntev. Ntau lub chaw tsim khoom tam sim no tsim qauv ntawm PTFE rau tag nrho cov kab hnyav, thiab tsuas yog tuav cov hlau tsis huv rau cov dej siv hluav taws xob lossis cov dej yaug.
Thaum kawg qhov kev txiav txim siab ntawm PTFE thiab stainless hlau cua sov raj yog ib qho kev ua haujlwm ntawm cov tshuaj ib puag ncig. Lub inertness ntawm PTFE piav qhia nws tus nqi rau hnyav acids thiab nruj purity yuav tsum tau. Stainless hlau tseem muaj peev xwm nyob rau hauv cov xwm txheej me me. Kev lag luam uas txuas ntxiv hloov pitted stainless hlab tsis yog hmoov zoo, nws tsuas yog siv cov cuab yeej tsis raug rau txoj haujlwm. Hloov mus rau PTFE ib zaug thiab koj tuaj yeem tshem lub rhaub ntawm koj daim ntawv teev cov teeb meem kev saib xyuas uas ua rau rov tshwm sim dua. Cov chemistry tseem mus, cov khoom nyob twj ywm ntshiab, thiab cov peev nyiaj thaum kawg tau so.