Cov txheej txheem kwj feem ntau muaj cov khib nyiab-catalyst nplua, ntxhia precipitates, los yog cov hlaws polymer. Kev tswj cov khib nyiab no yam tsis tau ntsaws lossis eroding lub tshav kub exchanger yog ib qho tseem ceeb ntawm kev xav txog qhov twg graphite thiab PTFE coj txawv txawv heev. Xaiv cov khoom tsis raug ua rau muaj kev tu ntau zaus, ua tsis tiav ntxov, lossis lub sijhawm poob qis. Kev nkag siab meej txoggraphite vs PTFE slurry tuavcov yam ntxwv qhia qhov kev xaiv raug rau txhua daim ntawv thov.
Graphite Block Exchangers: Abrasion -Resistant tab sis Pluggging-Ntawm
Graphite heat exchangers, feem ntau nyob rau hauv thaiv los yog cubic daim ntawv, feature ncaj, drilled passages (feem ntau 10-20 mm nyob rau hauv lub cheeb) los ntawm cov txheej txheem dej ntws. Cov khoom siv nws tus kheej muaj qhov ua tau zoo tsis zoo vim nws qhov nyuaj, nrog rau kev ua haujlwm ntawm cov khoom tawv tawv zoo dua li PTFE. Cov qib carbon graphite siv hauv cov khoom siv hluav taws xob ua kom pom kev hnav zoo tiv thaiv crystalline lossis hlau nplua.
Txawm li cas los xij, kev sib tw nrog graphite tsis yog yaig tab sis hydraulic thaiv. Cov kab me me, ncaj qha tsis muaj kev hloov pauv lossis hla dhau. Yog hais tias cov khib nyiab nyob, agglomerate, los yog muaj cov khoom loj dua li txoj kab uas hla, plugging tshwm sim sai. Fibers, nplaum precipitates, los yog irregularly zoo li cov khib nyiab choj hla lub qhov nkag. Thaum ib txoj kev raug thaiv, kev tu yuav tsum tau siv tshuab rodding lossis tshuaj lom neeg tawg, feem ntau yuav tsum tau tshem tawm cov kev pabcuam. Tsis muaj lwm txoj hauv kev ntws; ib lub qhov thaiv qhov txo qhov muaj peev xwm hloov hluav taws xob, thiab ntau qhov thaiv tuaj yeem ua rau lub tsev tsis zoo.
Graphite block exchangers tsis pom zoo rau cov kev pab cuam nrog fibers, loj agglomerates, los yog tej yam khib nyiab uas zoo li nyob rau hauv qis -flow tej yam kev mob. Lawv ua tau zoo tshaj plaws hauv cov dej ntshiab, tsis yog- cov kua abrasive uas muaj cov thermal conductivity siab (100–150 W/m·K) yog qhov yuav tsum tau ua.
PTFE Tube Exchangers: Flexibility tiv thaiv plugging, yooj yim rau yaig
PTFE (polytetrafluoroethylene) raj bundles muab ntau txheej kev lag luam sib txawv -offs. PTFE yog inherently mos. Muab piv rau graphite, nws erodes sai dua thaum raug cov tawv, ntse hais txav ntawm siab tshaj tawm. Abrasive solids-xws li xuab zeb, catalyst fines, los yog hlau oxides- tuaj yeem hnav los ntawm cov phab ntsa hauv lub sijhawm, ua rau cov dej xau. Cov txheej txheem nrawm dhau los ua qhov tseem ceeb: rau cov slurries, tswj qhov tsawg kawg nkaus ntawm 1.5-2 m / s tiv thaiv kev teeb tsa, tab sis tshaj tawm tshaj 3 m / s ua kom yaig.
Conversely, PTFE hlab yog tsis tshua muaj plugging rau ntau yam. Tus du, tsis yog -stick bore tiv thaiv cov khoom los ntawm adhering. Qhov hloov tau yooj yim ntawm PTFE tso cai rau lub raj kom nthuav dav me ntsis, dhau ntawm qhov loj me me uas tsis muaj kev puas tsuaj mus tas li. Lub raj ntim kuj tseem muab ntau txoj hauv kev sib txuas (feem ntau pua ntawm cov me me - txoj kab uas hla), yog li ib lub raj thaiv ib leeg muaj qhov cuam tshuam tsawg heev rau tag nrho cov cua sov hloov. Kev ntxuav feem ntau tuaj yeem ua rau hauv qhov chaw los ntawm kev thim rov qab los yog dej ntws tawm.
PTFE qhov yooj yim yog qhov kom zoo dua hauv cov kev pabcuam qias neeg uas cov khib nyiab yog mos, tsis xwm yeem, lossis tam sim no ntawm qhov tsis tshua muaj siab. Rau cov ntawv thov nrog cov khoom me me es tsis yog cov slurries tas mus li, PTFE tube exchangers muaj kev ntseeg siab, qis -kev tu vaj tse.
Kev txiav txim siab lub moj khaum: Cov yam ntxwv ntawm cov khoom txiav txim siab qhov kev xaiv
Ua tiavgraphite vs PTFE slurry tuavkev xaiv nyob ntawm qhov kev ntsuam xyuas ntxaws ntawm cov khoom tam sim no. Cov kev txiav txim siab hauv qab no qhia cov lus pom zoo:
| Khoom yam ntxwv | Graphite Block | PTFE Tube |
|---|---|---|
| Particle loj | < 1/3 of passage diameter (typically <3–6 mm) | Muaj peev xwm kis tau mus txog rau lub raj ID (feem ntau 5-10 mm); yooj pab |
| Particle hardness | Kev tiv thaiv zoo (Mohs 1-2) | Tsis zoo kuj; zam cov khoom ntse lossis tawv abrasive |
| Particle puab | Rounded los yog angular tau; zam fiber ntau | Fibers thiab mos agglomerates kis tau yooj yim |
| Nco ntsoov | < 5% by volume preferred; higher risk of settling | Txog li 15-20% ua tau nrog kev tshaj tawm txaus |
| Kev nplaum / adhesion | Yuav foul thiab choj hla qhov | Tsis yog -stick nto tiv taus adhesion |
Rau kev nplua, nyuaj, nrawm- txav slurries- xws li cov khoom siv hluav taws xob zoo hauv cov dej hydrocarbon lossis cov ntxhia slurry hauv hydrometallurgy- cov khoom siv tsis zoo. Ceramic los yog silicon carbide cua sov exchangers yuav tsum tau rau xws li xav tau kev pab cuam abrasive.
Rau cov mos mos los yog qeeb - txav cov khib nyiab-polymer hlaws dai, lom slurries, los yog precipitated ntsev-PTFE yog feem ntau zoo dua zam vim nws plugging kuj thiab cleanability. Graphite tseem yog qhov kev xaiv zoo tshaj plaws rau cov ntshiab, tsis yog - cov kua abrasive qhov twg cov thermal ua haujlwm siab yog qhov tseem ceeb thiab cov khoom tsis muaj lossis tsis zoo.
Cov Tswv Yim Qhia Txog Kev Pabcuam Slurry
Thaum tuav cov khoom khib nyiab- cov kua dej ntim hauv PTFE exchangers, ntws nrawm yuav tsum txaus los tiv thaiv kev daws teeb meem. Qhov tsawg kawg nkaus ntawm 1.5-2 m / s yog pom zoo kom khaws cov khoom hauv kev ncua. Periodic flow reversal lossis flushing pab tshem tawm txhua yam khoom siv.
Nyob rau hauv graphite exchangers, upstream filtration los yog ib tug strainer (mesh loj 1-2 hli) tuaj yeem tiv thaiv cov khoom loj los ntawm kev nkag mus rau hauv cov ntawv thaiv. Kev saib xyuas tsis tu ncua ntawm kev poob siab thoob plaws lub exchanger kuaj pom thaum ntxov plugging ua ntej muaj peev xwm tsis txaus siab.
Xaus
Kev tuav cov khib nyiab yuav tsum tau ua tib zoo ntsuam xyuas ntawm qhov loj me, hardness, thiab ntws tswj, raws li graphite thiab PTFE ua tsis tau raws li qhov sib txawv. Graphite resists puas tab sis ntsaws yooj yim; PTFE tuav cov khoom muag muag thiab nplaum yam tsis thaiv tab sis erodes nyob rau hauv qhov nyuaj particle nres. Tsis muaj kev daws teeb meem universal rau slurry lub luag haujlwm. Kev xaiv cov khoom siv hluav taws xob ua tau zoo xav tau kev nkag siab zoo ntawm cov kua dej, suav nrog tag nrho nws cov kab mob sib kis - tsis yog cov khoom sib xyaw xwb. Thaum cov khoom khib nyiab tsis paub los yog qhov sib txawv heev, kev tsim qauv tsim nrog cov kab ntau dhau (graphite) lossis cov khoom siv hloov tau (PTFE) muab txoj hauv kev nyab xeeb tshaj plaws rau pem hauv ntej.
