Cov neeg siv khoom lag luam feem ntau tau lees paub tias PFA txheej tuaj yeem tiv taus tag nrho cov kua qaub nrog rau hydrofluoric acid, tsis tau ntev - lub sij hawm immersion nyob rau hauv siab - kub, siab - concentration fluoride nruab nrab tseem yuav ua rau gradual txheej degradation, pinhole tiam thiab substrate corrosion. Txawm hais tias PFA muaj cov tshuaj tiv thaiv zoo heev tiv thaiv cov kab mob corrosive, huab cua fluoride ua haujlwm yuav ua rau cov txheej txheem ruaj khov ntawm cov txheej txheem fluoropolymer thiab ua rau lub tshuab cua sov ua ntej. Kab lus no txheeb xyuas cov txheej txheem tsis ua haujlwm thiab cov txheej txheem ua kom zoo dua.
1. Intrinsic Chemical Resistance Principple of PFA to Hydrofluoric Acid
PFA molecular skeleton yog tsim los ntawm cov pa roj carbon -fluorine covalent daim ntawv cog lus nrog lub zog siab heev. Ntawm qhov kub thiab txias tsis tshua muaj siab hydrofluoric acid, HF tsis tuaj yeem rhuav tshem C-F lub ntsiab saw, yog li cov txheej txheem tuaj yeem cais cov hlau hauv qab yeeb nkab zoo thiab paub txog kev tiv thaiv kev tiv thaiv- tiv thaiv corrosion. Sib txawv ntawm quartz iav thiab titanium uas hnov mob hnyav nrog HF ib zaug, PFA yuav tsis yaj sai sai hauv cov tshuaj fluoride, uas yog qhov laj thawj tseem ceeb vim li cas nws thiaj dhau los ua cov khoom siv hluav taws xob nkaus xwb siv rau hydrofluoric acid pickling tanks. Tab sis qhov kev tiv thaiv no tsis tas mus li thiab tsis txwv.
2. Peb txoj hauv kev degradation nyob rau hauv siab -Qhov kub thiab txias Fluoride ib puag ncig
(1) Thermal- pab nkag mus rau HF me me molecules
HF belongs rau me me polar molecules. Nyob rau hauv cov cua kub siab tshaj 80 degree, molecular kev ua kom muaj zog tsis tu ncua. HF tuaj yeem maj mam nkag mus raws li qhov sib txawv me me ntawm PFA resin particles hauv txheej txheej, sib sau ntawm txheej txheej thiab hlau substrate. Cov khoom siv hydrofluoric acid etches cov yeeb nkab steel los tsim cov xeb thiab cov pa roj hydrogen, tsim kev nthuav dav sab hauv thiab thawb PFA txheej rau blister thiab delaminate.
(2) Txheej aging induced los ntawm ntev -lub sij hawm thermal load
Hauv cov khoom siv hluav taws xob nruab nrab cua sov fluoride, kev kub hnyiab qhuav thiab cua sov hauv zos feem ntau tshwm sim. Qhov kub thiab txias ua rau ib feem ntawm C-F daim ntawv cog lus ntawm PFA nto, tsim cov dawb radicals. Cov pab pawg no hnov mob nrog HF hauv nruab nrab, ua rau lub ntsej muag chalking, microcrack propagation thiab tsim cov pinholes nkag.
(3) Mechanical defect expansion nyob rau hauv fluoride yaig
Kos thiab me me abrasions tsim thaum lub sij hawm thauj mus los thiab kev teeb tsa tsis pom thaum xub thawj. Fluoride kua invades los ntawm cov ntsiab lus puas, nthuav qhov tsis xws luag raws li txheej txheej interface, thiab hloov me me puas mus rau hauv loj - cheeb tsam tev nyob rau hauv ob peb lub lis piam ua hauj lwm.
3. Qhov tseem ceeb cuam tshuam rau kev ua kom cov txheej txheem ua tsis tiav
Kub: Cov kua kub ntau dua, HF nrawm dua nkag mus rau txheej txheej; Kev pabcuam lub neej poob qis thaum qhov ntsuas kub siab tshaj 180 degree.
Concentration: Siab -concentration hydrofluoric acid thiab cov kua qaub sib xyaw uas muaj ammonium fluoride muaj zog permeability dua li dilute HF kua.
Txheej thickness: Ib txheej nyias txau hauv qab 0.6 hli tsis zoo compactness thiab luv los tiv thaiv -permeation life; txheem thickness yuav tsum tau tswj ntawm 0.8 ~ 1.5 hli.
Static standby: Kev kaw ntev nrog HF cov kua khaws cia hauv lub tank ua rau muaj kev sib txuas ntxiv ion ntxiv thiab ua rau muaj kev cuam tshuam tsis zoo rau hauv cov txheej txheem.
4. Lub Hom Phiaj Txhim Kho & Kev Pabcuam Lub Neej Ntxiv Kev Ntsuas
Txais ntau- txheej txheej txheej txheej txheej txheej txheej txheej txheej txheej txheej txheej txheej txheej txheej txheej txheej txheej txheej txheej txheej txheej + txheej txheej tuab tuab + txheej txheej txheej txheej + txheej txheej tiv thaiv- txheej txheej txheej txheej txheej, txo qis sab hauv cov txheej txheem ntawm txheej thiab thaiv cov kab nkag mus rau hauv molecular.
Strictly control surface power density, avoid local overheating and dry burning; nruab qhov ntsuas kub sib cuam tshuam kev tiv thaiv kom txwv qhov nruab nrab kub hauv qab 160℃rau kev ua haujlwm ntev -.
Ua 100% siab -voltage spark leakage detection ua ntej xa khoom kom tshem tawm cov pinholes hauv txheej txheej.
Standardize ntawm- qhov chaw ua haujlwm: tso cov kua tank kom tiav thaum lub sijhawm kaw ntev -; tsis tu ncua ntxuav cov av sediment kom tiv thaiv qhov chaw kub hauv zos fouling.
Ua txhua lub hlis twg lub txim uas tsis yog- kev kuaj kev puas tsuaj rau hauv - cov khoom siv pabcuam; kho me me pinholes nrog tshwj xeeb PFA kho kua nplaum kom raws sijhawm kom tsis txhob nthuav dav ntxiv.
5. Cov ntaub ntawv xaiv ciam teb kom meej meej
Tsawg- kub dilute HF kev ua haujlwm: PFA txheej lub rhaub yog qhov kev xaiv zoo tshaj plaws nrog tus nqi qis thiab kev ua haujlwm ruaj khov.
Siab - kub concentrated HF tas li ntau lawm: Kev cai thickened multi- txheej PFA khoom yuav tsum tau; tsis muaj lwm yam khoom siv hluav taws xob hloov hluav taws xob muaj nyob hauv kev lag luam pa.
Fluoride nruab nrab siab tshaj 260 degree: PFA tsis tuaj yeem siv vim cov khoom muag muag thiab decomposition, thiab tshwj xeeb muaj nuj nqis hlau cua sov cov ntsiab lus yuav tsum tau kho.
表格
| Influencing Factor | Degradation Phenomenon | Txoj Kev Txhim Kho |
|---|---|---|
| Kub kub HF | Internal bubbling thiab txheej peeling | Txwv kub ua haujlwm & ntxiv kev tiv thaiv overheat |
| Tsis txaus txheej thickness | Kev nkag mus sai thiab pinhole to | Multi- txheej txau kom ntseeg tau tias tag nrho cov thickness Ntau dua los yog sib npaug rau 0.8mm |
| Tsis huv kaw nrog cov kua seem | Hidden interfacial corrosion | Npua lub tank tso dej thaum lub sijhawm khoom siv |
| Thawj txheej me me tsis xws luag | Local perforation tsis ua hauj lwm | Tag nrho -kev kuaj xyuas ua ntej lub Hoobkas xa khoom |
Xaus
PFA yog qhov tsim nyog tshaj plaws los tiv thaiv- cov khoom siv cua sov rau cov fluoride- uas muaj cov xov xwm ntawm cov kev xaiv ib txwm siv, tab sis nws txoj kev tiv thaiv yog nyob ntawm kev ua tiav txheej txheej thiab kev tswj qhov kub thiab txias. Los ntawm kev ua kom zoo dua cov txheej txheem txau thiab kev tswj hwm kev ua haujlwm txhua hnub, qhov teeb meem kev laus ntawm PFA hauv hydrofluoric acid ib puag ncig tuaj yeem tswj tau kom ua tiav ntev - voj voog ua haujlwm ruaj khov.
