Applicationsofmembraneprocessesandproductionofmembrane

膜技術應用及膜制造6 MembranesinwatertreatmentWhatisamembrane?ApplicationsofmembranesFoodprocessingMedical(dialyses,breathing)Watertreatment(drinkingwater,MembraneBioreactor)Industrial

production(gasseparation,extraction,pervaporation)Basic

principles,nomenclatureorhowdowecallwhat?Units(Cp,Retention,Flux,MTC,TMP,Osmotic

pressure,Recovery)Driving

forceFiltrationspectrumProductionofmembranesMembranetypesModuleconfigurations(flt

plate,tube,fibre,capillary,spiral

wound)Procesconfigurations(crossflow,deadend,semi

deadend)Membrane

applicationsFoodprocessingBeer,dairy,juice,yeastMedical(dialyses,breathing)Watertreatment(drinkingwater,MembraneBioreactor)Industrial

production(gasseparation,extraction,pervaporation)FoulingMembrane

bioreactorsSome

applicationsofmembranesinwatertreatment6 membranesNomenclatureFeedConcentrateBrinePermeateTransMembrane

PressureSurfaceStructureFoulingCategoriesofMembraneProcessesPressureDrivenProcessesReverseOsmosis,Nanofiltration

Ultrafiltration,MicrofiltrationOtherProcesses-Dialysis,ElectrodialysisDrivingforceisconcentrationdifferenceDrivingforceiselectricpotentialdifferencemembraneFeedProductwater=permeateConcentrate=Retentate=BrinePressuredrivenMembranefiltrationmembrane

microfiltrationultrafiltrationnanofiltrationreverseosmosisDecreaseofporesize/increaseofpumpingpressureParticlesizeandSeparationsize1mm

0.1mm

10nm

1nm

BacteriaVirusNutrientSandSiltClayQuestion:Pleasegiveappropriatesizesof….ParticlesizeandSeparationsize1mm

0.1mm

10nm

1nm

Nutrients

Natural

OrganicMatters

Viruses

Bacteria

Proteins

Ions

Pesticides,Endocrine

disrupting

chemicals

Clay,

Silt

Organic

debris

Pleasegiveappropriateseparationsizesof…ReverseOsmosis,Nanofiltration,Ultrafiltration,Microfiltration,FilterPapersSolutesizeandSeparationsize1mm

0.1mm

10nm

1nm

Nutrients

Natural

OrganicMatters

Viruses

Bacteria

Proteins

Ions

ReverseOsmosis(RO)

Nanofiltration(NF)

Ultrafiltration

(UF)

Microfiltration

(MF)

Pesticides,Endocrine

disrupting

chemicals

Clay,

Silt

Organic

debris

Electrodialysis(ED)

ParticlesizeversusP(bar)Particlesizeinm.AppliedpressureCutoffgraph“Production”ofamembranefilter

Q-permeate=JvxA

Permeate

flowrateQ=m3/h

FluxJv=m3/m2.h

AreaA=m2Permeabilityofamembrane

Ap=Jv/ΔP

Ap

=permeabilityinm3/m2.h.Pa

Jv=Fluxinm3/m2.h

ΔP=Trans

Membrane

Pressure=

Pfeed–Ppermeate

(in

Pascal)CalculationMembranesurfaceAsingletubularmembranehasadiameterof6mm.Thelengthofthemodule=3,65meter.Inonemodulethereare55membranestogether.Whatisthetotalmembranesurfaceareainthismodule?Answer:Areaof1membrane=2πrxl2πrxl=2π0,003x3,65=0,069m2Totalarea=55x0,069=3,78m22r=D=6mmL=3,65mExample

calculationFlux(Jv)andPermeability(Ap)AUFmembrane

with12tubesof?5mmandalengthof6m.giveapermeate

flowof325litres/houratapressureof3,5bar.WhatistheFlux?WhatisthePermeability?Answer:Thetotal

applied

membrane

area(A)=12x6mx2.л.0,0025m=1,131m2Flux

Jv=325litres/1,131.H=287,36l/m2.hPermeabilty

Ap=Jv/ΔP=287,36/3,5=82,1l/m2.h.barExampleTransMembranePressure:Theinletpressureinthemembraneis3,6bar.Theoutletpressure=3,3bar.Thepermeateoutlethasapressure0,3bar.WhatistheTMPoverthismembranemodule?2r=D=6mmL=3,65mPinPoutFeedflowAnswer:TMP=Pfeed–PpermeatePfeed=(Pin+Pout)/2TMP=(3,6+3,3)/2-0,3=

3,15barSome

other

aspects:RecoveryS(some

times

called

Yield)RetentionRSelectivity

βRejectionSaltPassage(inNF&ROapplications)Cut

off

MembraneTransferCoefficientRecovery(S)S=Qpermeate/Qfeed

Example1ofRecovery(S)ofmembrane

processQfeed=12,5m3/hQretentate=Qconcetrate=4,5m3/hWhatistheoverallrecovery? Qpermeate=12,5–4,5=8m3/h

Recovery=8/12,5x100% =64%Example2ofRecovery(S)ofmembrane

process

with

backwashQp=8m3/hQf=8,2m3/hPermeate

productiontime=20minutes

After

every20minutes

production

thereisa30seconds

backwash

with

aflowof24m3/h.TheFeed

flowisgoing

on

thenandisnotaffectedbythebackwash.Whatistheoverallrecovery?Recovery=(20,5x8)–(0,5x24)x100%=99,4% 20,5x8RetentionR=Cr–Cp

=1-Cp Cr

CrSelectivityβ=Cr/CpRetention/SelectivityexampleTherawfeedwaterofaUFmembranehasaTSconcentrationof25mg/lThepermeatehasaTSconcentrationof2,8mg/l.Therecoveryis80% -WhatistheTSretention? -WhatistheselectivityofTSforthis membrane?25mg/l2,8mg/l?mg/lCf=25mg/lCp=2,8mg/lCr=?mg/lMass

balance:RecoveryS=80%so

Qp=80%ofQfeed100.25mg/l=80.2,8mg/l+20.?mg/lCr=(2500–224)/20=113,8mg/l

RetentionAnswer:TotalSolidsRententionR=R=(Cr–Cp)/Cr

=(113,8-2,8)/113,8x100% =97,5%Selectivity

β

for

Total

Solidsβ=Cr/Cp=113,8/2,8 =40,6%If

retentionR=0%then

β=1IfR=100%then

β=∞

Flux

Jvisdepending

on:

-TransMembrane

Pressure

-Temperature

≈

Viscosity

-Resistantofthemembrane

(including

fouling)

-Structure

-Concentration

PolarisationRelationTemp&FluxThedynamic

viscosity

η=497.10-3 (T+42,5)1,5T=temperatureofthepermeate(Celcius)Η=dynamic

viscosityinPa.sPa.s=N.s/m2=10Poise;1centipoise(cP) =0,001Pa.sTemperature

higher=fluxhigherDynamic

viscosityofwaterat25degreesC=0,896cPResistanceModelinamembraneI=ER1+R2+R3ER1R2R3IRmRcRgRpJvJv=DPm(Rc+Rg+Rp

+Rm)SeparationofresistancefactorstoCake,Gel,Plugging,Membrane.ModelonflowinmembraneporesJv=Ak.DP.dp32.m.Dz2Jv:Ak:DP:dp:m:Dz:VolumeFluxPoreOpenRatioAppliedPressurePoreDiameterViscosityMembraneThicknessConcentrationPolarisationFluxConcentrationProfileCbCmDifferenceinconcentrationbetweenCbandCmiscalledconcentrationpolarizationCmCb

Jv=k.ln()k:MasstransfercoefficientfeedNormalOsmoseHigher

concentrationLower

concentrationsemi-permeabelemembraanWatertransportReversedOsmoseForceSemi-permeabelemembraneHigherconcentrationLowerconcentrationWatertransportProductionin(NF/RO)membranesA=permeabilityinlitres/m2/barFluxJwinliters/m2.hourRejection

byNF/ROmembranesSaltRetention[%]0204060801000102030405001020300102030WaterFlux(L/m2h)Feedpressure(bar)Feedpressure(bar)WaterSaltSaltFlux(kg/m2h)OsmoticpressureOsmoticpressureDH=29bar=290meterwatercolumnwatermembraneriverwaterseawaterriverwaterseawaterQuestion:WhatisЛtheOsmotic

PressureofSeawater?

[NaCl]inseawater=35gram/liter

35g/58,5molNaCl=0,6mol/l

0,6molNa+0,6molCl=1,2mol

Л=1,2x24bar=29bar!!!ReverseosmosisinacontinuousprocessSeawater

ProductionofamembraneBasisisanorganicpolymer

(PAN,PES,CA,PVDF).

Thepolymerdeterminesthechemicalresistance,foulingbehavior,etc.

Castingsolutionispreparedbymixingthispolymerwithanorganicsolvent(NMP,DMF,acetone).

Thesolventmustbemisciblewithwater.ProductionofamembraneAlsospecificsubstancesareaddedtothecastingsolution(e.g.pore-formersornon-solvents).

Coagulationinwatergivesphase-separationresultinginapolymerpoorphase(‘thepores’)andapolymerrichphase(‘themembranebody’)ProductionofamembraneAdemonstration

inthelabafterinstruction!!Nesessaryequipment:PESpolymer

NMPSolventsolutionWaterGlass

sheetsMetal

knife=membraneinstrumentPoly

Sulfon

(PS)PSinNMPsolutionglassplatesCleaning

glassplatesimportantMembrane

knife(0,2mm)Fillingtheknife

with

PS

solutionArie

my

collegeisdemonstratingCreatingamembranefilmMovevery

gently

toleftPutslowlyinthewaterfor….Membraneisfloating

after

coagulationAfter

coagulationOutofthewaterTakeofamembraneThephotooftheproduced

membraneMakesheetsofitinamoduleMakeamoduleofitMorethan

one

membraneSubmergeinaMBRtankStructureofMembranesPorousvsNonPorousHydrophilicvsHydrophobicPolymericvsInorganicPorous-NonPorous,SymmetricandAssymetricDense(Nonporous)PorousSymmetricPorousasymmetricRO,NFUF,MFMFSkinSupportPorousSymmetricMembranesNucleporeMembraneCelluloseMembraneSymmetricmembraneAsymmetricMembranesDenseLayerPoroussupportFiberSupportPoresizeCeramic

membrane

pictures(CEM)Membranestructurestructure:symmetricasymmetric

shapes:flatsheettubular:tube (d>3mm)capillary (0.5<d<3.0mm)hollowfibre (d<0.5mm)ModuleshapesFlatSheetSpiralWoundTubularHollowFiberContainedvsSubmergedFlatsheetmodulePlateandFrameModuleUFPolyacrylo

nitrile(PAN)Polyvinylidenefluoride(PVF)Polysulfone(PS)Sulfonated

Polysulfone(SPS)Tubularandcapillarymembranes

Tubular

membranewww.vito.beTubularmembranes(contained)HollowFiber(capillar)OutsideInVSInsideOutFromCatalogofTorayCapillary8inchmoduleMonolith(demo)InorganicMembranes-CeramicMF,UFRecentlyNF-Porousglass-ZirconiumCeramictubesFlatsheetsSpiral-WoundRO/NFModuleFlowINSpacerMembranePermeateConcentrateYou

can

make

your

own

spiral

woundmoduletoday!!!TwoA4papersCottonsheetA4(ifavailable)Shears

to

cutGlue

forpaperPlastictubewithaslid(prefabricated)Reverse

Osmose-installation+/-variousconfigurationsOperationmodesDeadendandCrossflowMembranefiltrationdead-endMembraneWastewaterPermeatefeedMembranefiltrationcrossflowWastewaterPermeateconcentratefeedmembraneAirinjectionDead-endFiltrationtimeYieldCakeThicknessCross-flowfiltrationtimeCakeThicknessYieldSemidead-endfiltrationCross-flowfiltrationAdvantages:turbulentflowcontinuousconcentratedischargecontrolofcake-layerbuild-upDisadvantages:morecomplexprocesslayouthigh(er)energyconsumptionhigh(er)investmentcostCascadesinglepasssystemTwo-stagerecirculationsystemFoulingofmembranesFoulingReversible

foulingIrreversible

foulingBiofoulingPore

blockingScalingResistanceModelI=ER1+R2+R3ER1R2R3IRmRcRgRpJvJv=DPm(Rc+Rg+Rp

+Rm)SeparationofresistancefactorstoCake,Gel,Plugging,Membrane.RejectionbyUF/MFmembranesGlobularProteinLinearpolymerSolutePepsinCytochromeCPolydextranMW(kDa)3513100Rejection(%)90700PoroussupportSelectivemembraneskinGlobularproteinLinearmacromoleculeCakelayer

formationMembraneParticleColloid/proteinCake/foulinglayerFlowdirectionDrivingforce?pFoulinginMF/UFDecreaseinfluxdueto:Pore-plugging,adsorptionandcake-layerformationNoconcentrationpolarizationofsalts

noscalingIngeneralconcentratedfeedsolutionscontaininglargeparticles(size10nm–25μm).

Thisresultsinlowback-diffusionrates,fastcakelayerbuild-upandporeblocking

lowproduct-fluxes(1/10oftheCWF)ComplexcakelayerstructureFoulinginNF/ROFoulingbehaviordiffersfromUF/MFdueto:Lowerfluxesandpresenceofsmallermoleculeshigherback-diffusionandingeneralnothickcakelayerformationChargedmembranesurfaces(ingeneralnegative)adsorptionofcolloidsandbiologicalmatterScaling(CaSO4,CaCO3)Foulingreduction/cleaningMembranepropertiesandmoduledesignOptimumprocessconditions(lowTMP)Cleaningregimehydrauliccleaning(backwash,forwardflushandairflush?)chemicalcleaningrelaxationPre-treatmentofthefeed

(flocculation/coagulation,pH

adjustment)Backwash(=Backflush)SuspensionMembranePermeateFiltration

modeBackflushing

modeto

drainFluxTimewith

backflushingwithout0negative

flowSuspensionMembranePermeateFiltration

modeBackflushing

modeto

drainFluxTimewith

backflushingwithout0negative

flowBackwash(=Backflush)Forward

Flush

production

forward

flushBackFlush

production

forward

flush& backflushpermeateAirFlushAirFlush?bubbleflowslugflowannularflowForward

Flush

with

airflush

production

forward

flush

with

airflush&backflushMembranefiltrationsemidead-endMembraneWastewaterPermeatefeedDead-end

production-run,start

buildingup

fouling

layerpermeatepermeatepermeatepermeatefeedMembranemoduleDead-endatendofproductionrunBuildingup

fouling