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Gas/Liquid Separation Technology
Sulzer Chemtech
Introduction
2
Content Page
Introduction 2
ProductSummary 4
MistElimination 8
KnitMeshMistEliminators 11
Mellachevron 14
AxialCyclonicDevices 17
CombinedSystems 18
Applications 20
Sulzerisamajorplayerinthefieldofgas/liquid and liquid/liquid separation tech-nology, offering a full rangeof innovativeproducts and related services. Our com-mitment to development of technology,combinedwithapplicationknowhowandconsistent fabrication standards ensuresthatawell-engineeredsolutionisavailableformostseparationproblems.
Our expertise gained from hundreds ofsuccessful installations in a broad spec-trumofapplicationsensuresthatthebestpossible product is recommended foeeachindividualduty.
OurstrategicallianceagreementwithShellGlobal Solutions International B.V. pro-videsaccesstostateoftheartseparationtechnology,includingtheShellSwirltubeTMandSchoepentoeterTM.Theacquisitionofthe KnitMesh Separation Business hasadded KnitMeshTM Mist Eliminators andCoalescerstoourexistingproductrange.
Specialists in Retro-Fit and Performance Enhancement
Our engineering team relishes the chal-lenges associated with existing installa-tions.Professionaladviceandtailor-madeequipmentdesigns,foundedondecadesof experience, can overcome a host ofseparationproblemsrelatedto:
•changesinprocessconditions
•de-bottlenecking
•agingplant
•sub-optimalequipmentlayout
Introduction
3
Service and Supply
Sulzeroffersaflexibleandcomprehensiverangeofservicewhichcanbetailoredtosuityourprojectrequirements,including:
•processdesign
•feasibilitystudies
•detailedengineering
•equipmentmanufactureandsupply
•installation
0604 2500-11
Emergency Delivery
Sulzercan react to themostchallengingdeadlines and can assist with urgent re-placementorrepairofseparatorinternals.For emergencies, contact your nearestSulzerChemtechoffice-detailsofwhichcanbefoundatwww.sulzer.com
If installation services are required, ourtechniciansareavailableonyourworksitetomakesureyourequipmentmeetsspec-ificationsandyourprojectgoessmoothlyfrom start to finish. A Sulzer technicianinspectsyourequipmentbefore it leavesourplant.Atyourworksite,youcancountonourtechnicians,whoarespecialistsinseparationandmasstransfersystems,tomonitoreachphaseofyourinstallationtoensureyouareupandrunningontime.
Research and Development
Werecognizethatinvestmentinresearchand development is an essential com-ponent for long term success. We havelaboratories where separation internalsanddesigntechniquescanbetestedanddevelopedinfullyinstrumentedpilotscalecolumns.
Increasingly, computer models are beingused to aid the design of new products.Sulzerusescomputationalfluiddynamics(CFD) models to simulate product perfor-
mance.Thistechniquenotonlyeliminatestherequirementforexpensiveprototypesto be constructed, but provides a muchgreater understanding of the productsoperationinadvanceofanylaboratoryoroperational trials. CFD simulations havealsobeenused togreateffect in solvingflow distribution problems in a variety ofsystems.
0607 2503-15
4
Type of Separator
KnitMeshTM
MistEliminator
KnitMeshV-MISTERTM
MellachevronTM
MistEliminator
ShellSwirltubeTM
ShellSwirltubeLightTM
Materials
StainlesssteelsAlloyC22,C276,400,625,825and20,CopperPP,FEP,ETFE,PTFE,Glassfibers
StainlesssteelsAlloyC22,C276,400,625,825and20,CopperPP,FEP,ETFE,PTFE,Glassfibers
StainlesssteelsAlloyC22,C276,400,625,825and20,PP,PVC,PVDF,FRP
Stainlesssteels,Alloy625,825
Stainlesssteels,Alloy625,825
Applications
Broadrangeofgas/liquidseparationproblems.ScrubbingsystemsandabsorbersEvaporatorsSteamdrumsKnock-outpotsGlycoldehydrationInertgasscrubbersMSF/MEDdesalinationSulfuricacidabsorbersanddryers.
Broadrangeofgas/liquidseparationproblems.ScrubbingsystemsandabsorbersEvaporatorsSteamdrumsKnock-outpotsGlycoldehydrationInertgasscrubbersMSF/MEDdesalinationSulfuricacidabsorbersanddryers.
Broadrangeofgas/liquidseparationproblems.ScrubbingsystemsandabsorbersEvaporatorsSteamdrumsKnock-outpotsGlycolcontactorsInertgasscrubbersMSF/MEDdesalinationSulfurcondenserFlue-gasdesulfurization(FGD)
Gasprocessingapplications;inletsepa-rators,turbo-expandersuctiondrums,dew-pointseparators,compressorsuctiondrums,glycolcontactors.
Gasprocessingapplications;inletsepa-rators,turbo-expandersuctiondrums,compressorsuctiondrums.Scrubbingsystemsandabsorbers,PEBneutraliza-tioncolumn.
Product Summary
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5
Typical operational Range
RelativelylowcapacitywithK-valuestypicallyupto0.107m/s(0.35ft/s).Highefficiencyseparationdowntodropletsizesof2to3µm.Pressuredroptypicallylessthan2.5mbar.Designsavailableforinstallationineitherhorizontalorverticalgasflow.
EnhancedcapacitywithK-valuestypicallyupto0.15m/s(0.49ft/s).Limitedtohorizontalinstallationwithverti-calgasflow.Highefficiencyseparationdowntodropletsizesof2to3µm.Pressuredroptypicallylessthan2.5mbarVeryeffectiveforheavyliquidloadings/irrigatedsystems.
HighcapacitysystemsavailablewithK-valuesupto0.45m/s(1.47ft/s)atthevanefaceinlet.Effectivedropletseparationdownto~20µm.Efficiencycanbeenhancedbycombina-tionwithKnitMeshpre-conditioners.Generallyforuseat:-surfacetension>10dynes/cm.-operatingpressure<60barinhydrocar-bonsystems.Pressuredropistypicallyintherange1to10mbar.Designsavailableforinstallationineitherhorizontalorverticalgasflow.
HighcapacitysystemswithK-valuesuptotypically0.25m/s(0.82ft/s)inthevessel.Effectivedropletseparationdownto~10µm.Efficiencycanbeenhancedbycombina-tionwithwiremeshpre-conditioners.Pressuredropistypicallyinregionof30mbar.
HighcapacitysystemswithK-valuesuptotypically0.25m/s(0.82ft/s)inthevessel.TheShellSwirltubeLightissuitableforhigheroperatingpressures,offershighercapacitiesthanvanepacksinstalledforverticalgasflowandisthere-foreausefulcomplementtoourMel-lachevronmisteliminators.
Characteristics
Manufacturedasaknittedwiremeshpacking.Canbeeasilytailor-madetosuitmostvesselshapesandsizes.Costeffectiveandversatilesolutionformostmistelimi-nationapplications.
Manufacturedasaknittedwiremeshpacking.SupportgridsfittedwithspecialV-MISTERdrainagechannelstoenhancedrainagecharacteristics.Canbeeasilytailor-madetosuitmostvesselshapesandsizes.Costeffectiveandversatilesolutionformostmistelimi-nationapplications.
Constructedfrombanksofparallelcorrugated,chevronprofiles.Highcapacitydesignsprovidecompactseparators-idealforgasprocessingapplications.Lowercapacitydesignsavailableforfoulingserviceandheavyliquidloadings.
HighperformanceSwirltubes(HPST)arrayedinboxesorbanksprovidecompactseparatorsdesignedasShellSMS,SVS,SMSMandSMMSMunits,andareidealforgasprocessingatallpressures.Suitableforuseinfoulingorwaxyservices.
ArrayofaxialcyclonesoriginatedfromtheShellConSepTMSwirltubedesign.ThedevicecanbecombinedwithaSulzerMellachevronorKnitMeshpre-conditioner.TheseparationefficiencyoftheShellSwirl-tubeLightislowerthantheShellSwirltubeandisintherangeofvanepacks.
Product Summary
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0604 2512
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6
Type of Separator
MKSMultiCassetteTM
MistEliminator
ShellSchoepentoeterTMandSchoepentoeterPlusTMInletDevice
TreelnletTM
Device
GIRZCycloneInletDevice
GITVVaporHorn
VantaTM
InletDeviceGITD
Materials
Stainlesssteels,Alloy625,825
Stainlesssteels,Alloy625,825
Stainlesssteels,Alloy625,825
Stainlesssteels,Alloy625,825
Stainlesssteels,Alloy625,825
Stainlesssteels,Alloy625,825
Applications
Gasprocessingapplications;inletseparators,turbo-expandersuctiondrums,compressorsuctiondrums,glycolcontactors.
TheSchoepentoeteristhemostcommonlyusedvaneinletdeviceforintroducinggas/liquidmixturesintocolumns.TheSchoepentoeterPlusisanadvancedfeedinletvanedevicewithconsiderablyincreasedde-entrainmentefficiencyandfirstchoiceforalldemandingtaskssuchasinvacuumtowers,crudedistillationandhydrocrackermainfrac-tionatorsandhighpressureseparators.
TheSulzerTreelnletisanaxialflowvanegasinletdeviceforverticalfeednozzles.Idealforbulkliquiddisengagementinawiderangeofservicesandapplications.
TheGIRZisusedasdefoamingcyclonicinletdevicetosuppressandbreakmanytypesofprocessfoams.Sometypicalapplicationsin-cludeFWKOdrums,flashdrums,testsepara-tors,2and3-phaseproductionseparators.
TheSulzerVaporHornGITVaswellasthenewSulzerVantaTMinletdeviceGITDareprimarilyusedinfractionatorswhereflashingfeedsre-quirehighpre-separationofanyfreeliquids.
Product Summary
0604 2507-4
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7
Typical operational Range
HighcapacitydevicewithK-valuesupto0.3m/s(1ft/s)inthecolumn.Highefficiencyseparationdowntodrop-letsizesof8to10µm.Efficiencycanbeenhancedbycombina-tionwithKnitMeshpre-conditioner.Nolimitationinoperatingpressure.Verysuitableforglycolcontactors.Meetsglycollossrequirementof0.1USgal/MMSCF(~14lt./MMNm3)orless
Generallydesignedatdynamicpressures<8000Pa,butcanperformwellathighervalues.Istypicallyusedforfeedshavingagasvolumefractionof>70vol%.Suitableforinstallationinhorizontalorverticalseparators.Suitableforliquidslugs.
TheTreelnletprovidesasuperiorliquidpre-separationandgasdistributionandisnormallyeffectiveuptodynamicpres-suresofabout10000Pa.
TheGIRZcyclonicinletdeviceutilizesthemomentumofthefeedstreaminletinor-dertogeneratehighg-forces.Defoamingisachievedasgasbubblesareseparatedfromtheliquidphasebythecentripetalforcesinthecyclonetubes.Gasisre-leasedfromthetopofthedeviceandthebottomopeningofthecyclonesissub-mergedbelowtheliquidintheseparatorinordertoavoidagas‘blowout’.
ThetangentialvanegasinletdeviceGITVandGITDcanbeusedforveryhighvaporvelocitiesinthefeedpipeofF-Factorsupto120Pa.Thefeedflowsradiallyaroundthevesselprojectingandcollect-ingtheliquiddropletsontheinnerwallofthevessel.
Characteristics
ThepatentedMKSMultiCassettedevicecombinesaxialcyclonicandcrossflowseparationtechnologytocreateanefficientandattractivemisteliminator.OneormoreMKSMultiCassettecandlesareassembledonasupportplateactingasliquidcollectorwithdrainpipes.
Constructedfrombanksofsweptvanes.Designsavail-ableforoperationinmostgas/liquidflowregimes.TheSchoepentoeterPlusisequippedwithsophisticatedcatchingrimstominimizeentrainment.
ByinstallingaTreelnletandahighefficiencyKnitMeshmisteliminator,liquidcarryoverlossesarereducedtovirtuallyzero.
TheGIRZconsistsofanarrangementoftwoormorecyclonessymmetricallyarrangedoffacommon,centrallylocatedheader.Thedevicecanbeinstalledinverticalorhorizontalvessels.Ifrequired,mixingelementsatthecy-clonegasoutletwillimprovethedistributiontothedown-streamdevice.
Thegasdistributionisperformedbybafflesaccordingtoavanegasinletdevice.Thedeviceissuitableforvesselinnerdiameterslargerthan4m.
ThenewSulzerVantaTMinletdevicecombineshighliquidseparationefficiencywithhighgasdistributionquality.
Product Summary
Flashzone
8
Liquidentrainmentinaprocessgasstreamcanbeformedbyeitherdynamicprocess-es,suchascontactbetweengasandliq-uid phases in a mass transfer operation,or thermalprocesses suchascondensa-tion.Forexample,dropletscanresultfrombubblesburstingorjettingatagas/liquidinterface-typically indistillationcolumns,evaporators,bubblecolumnsandfloodedpacked bed scrubbers. Where there isa high relative velocity between gas andliquid,droplets canbe sheared from thewetsurfaces.Thistypeofproblemislikelytooccur inventuriscrubbers,two-phaseflowinpipesandpackings.
Dropletscanalsobeformedbythermody-namicchangesinasystem.Forexample,vapor condenses when saturated gasesare cooled in condensers and heat ex-
changersand,althoughmostoftheliquidwill remainon theheat transfer surfaces,the gas can become supersaturated inplaces causing droplet formation. Thistypeofcondensationmistcanoccurdur-ingheatexchangeprocesses,thesuddenreleaseofpressureorbymixinghotandcoldgasstreams.Similarmistscanresultfromgasphasereactionswhichyieldaliq-uidproduct.Typicalapplicationssufferingfrom mist contamination include sulfuric,phosphoricandnitricacidplants.
Ifthegasistravellingtoofasttoallowtheliquiddroplets tosettleoutundergravity,theybecomesuspended(orentrained)inthegasor vapor. Inmost cases, the en-trainmentmustbe removed topurify thegasandpreventpotentialprocessorenvi-ronmentalcontamination.
Mist Elimination
Rain Drop Drizzle Mist Fog Entrainment fromwater cooling&spray coolingtowers
Sprayproducedbybubble burstingataliquidvaporinterface
Entrainmentfromevaporators, distillation&absorption
Condensate Condensatefrom from intercoolerson gascoolers compressionplant
Condensatefromhigh pressurecompressionplant
Knockoutdrums&collectorsfittedmeshmisteliminators
Knittedmeshmisteliminators
Vanemisteliminators
Cyclonicdevices
Baffles, Fiberbed louverseparators misteliminators
500 200 100 50 20 10 5 2 1 0.5 Dropletdiameter(microns)
Typicalprocessapplications
Typesandoperatingrangeofequipment
Sulzermisteliminatorsprovideaneffectivesolutiontoliquidentrainmentproblemsinmanytypesofequipmentincluding:
•scrubbing,absorption,strippingordistil-lationcolumns
•evaporators
•fallingfilmcondensers
•knock-outvessels
•3phaseseparators
•desalinationplants
•refrigerationplants
•gasdehydrationplants
•compressionsystems
9
Assumingthatgravityseparationcanbedisregardedasaneffectiveoption,theremain-ingmechanismsprovidethedesignbasisforSulzermisteliminationequipment:
•SulzerMellachevronTM –inertialinterception
•ShellSwirltubeTM –inertialinterception
•SulzerKnitMeshTM –inertial/directinterception
•SulzerMKSMultiCassetteTM –inertial/directinterception
Mist Elimination
Each mechanism is critically dependentonthedropletsizedistributionforagivenapplication.Forexample,ingasdryingap-plicationsusingglycolcontactors,dropletsizedistributionsareoftenintherangeof5-25µmandhighseparationefficiencyiscritical.Inthesecircumstances,directandinertialinterceptionarethemostappropri-ate mechanisms and separation is bestachievedby impingementof droplets onthewiresandfibersofhighperformancemeshmisteliminators.
Diffusional deposition is an importantmechanisminthedesignoffiberbedmisteliminators(candlefilters)usedforremov-alofsub-microndropletdispersionsfoundinapplicationssuchasacidmists.
Droplets Inertialinterception
Diffusion
DirectinterceptionFlowstreamlines
Gravity
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Severaltypesofmisteliminatorsareavail-ablefortheseparationofentrainedliquid.Tochoosetheappropriateequipment,thefourbasicmechanismsofdropletcaptureshouldbeconsidered.
•DiffusionalDepositionisonlyeffectiveinthe separation of very finely dispersedaerosols with droplets typically smallerthan1µm-thataresmallenoughtobeaffectedbyBrownianMotion.
•DirectInterceptionassumesthatadrop-let of a given diameter and negligiblemassfollowsthestreamlinearoundthe
‘target’wireorfiberandisseparatedasittouchesthetargetorcollectionfiber.
•InertialInterceptionconsidersthedropletmassandpredictshowmomentumwillmakeitdeviatefromthegasstream.
•Gravitational Deposition works on theprinciple that large, slow moving drop-lets may separate from a gas streamundergravity.This is restricted to largedropletsizesandlowsuperficialgasve-locities –making separatordimensionsbothprohibitively largeanduneconomi-cal.
10
v = maximumsuperficialgas velocity
rl = liquiddensity
rv = gasdensity
K = aconstantwhichisspecificto theseparationequipmentand isafunctionofprocess parameterssuchas:
rl - rv rv√v=K·
Table A: Summary of relative performance characteristics for mist elimination
Design Advice
Comprehensive performance informationis availableonawide rangeof standarddesigns,enablingSulzerengineeringstafftotailorthemisteliminatordesigntosuitmostapplications.
For best performance, it is important toachieveuniformgasflowdistributionandmaximum effective area, and recommen-dationcanbegivenonthemostappropri-atepositioning,intermsofdisengagementdistancesfromvesselinlet,outletandoth-ervesselinternals.
Sizing
For equipment based on direct and/orinertial interception, gas stream veloc-ity affects all three principles involved inseparation (impingement, coalescenceanddrainage).Flooding,orre-entrainmentof liquid,canoccuriftheflowofgaspre-ventsdrainage, and theeffective areaofthemisteliminatoristhereforeestablishedbydetermininganappropriatesuperficialvelocity for the equipment. The overallperformanceofthemisteliminatoristhena balance between efficiency and pres-suredrop.
•Liquidloading
•Gasandliquidviscosity
•Gaspressure
•Surfacetension
EquipmentType K-Value m/s ft/s
Gravity 0.07 0.23
SulzerMellachevron–simpleprofiles 0.13–0.17 0.42–0.56
SulzerMellachevron–highcapacityprofileswithdrainagechannels 0.15–0.45 0.49–1.46
SulzerKnitMeshMistEliminator 0.08–0.107 0.26–0.35
SulzerKnitMeshV-MISTER 0.08–0.15 0.26–0.49
SulzerMKSMultiCassette 0.10–0.30 0.33–1.00
ShellSMS,SMSM 0.25 0.82
Deratingfactorsareoftenappliedtoallowasafetymarginforexceptionalconditionssuchasliquidslugsandgassurges,andtheK-valuecanbeoptimizedtosuitspe-cificprocess conditions, andchallengingphysical properties such as low surfacetensionsystems.TheselectionofK-valueis therefore critical and we recommendthat designs should be checked by ourengineeringteam.
Gravity Baffles/louvers Vanepacks– Vanepacks– Axial Knitted Candles/ separators/ simplevanes withdrainage Cyclone meshmist fiberbeds knockoutdrums channels separators eliminators
Separation Gravitational Inertial Inertial Inertial Inertial Inertial/direct Directinterception/mechanism deposition interception interception interception interception interception diffusionaldeposition
Gashandling Low High High High Veryhigh Moderate Lowcapacity
Turndown Veryhigh 30% 30%-50% 30%-50% 30% 25% Veryhighcapacity Higherwith preconditioner
Efficiency Lowexcept Lowexcept Highdownto Highdownto Highdownto Veryhigh Veryhighat forlarge forlarge approx.25µm approx.25µm approx.10µm downto2-5µm sub-micron dropletsizes dropletsizes dropletsizes
Liquidload Veryhigh Veryhigh Moderate High High Moderate Lowcapacity
Solidshandling Veryhigh Veryhigh Moderate Low Moderate-high Low Verylowcapability
Liquidviscosity Suitablefor Suitablefor Suitableforhigh Pronetofouling Suitableforhigh Pronetofouling Unsuitableforhigh highviscosity highviscosity viscosities/waxes withhighliquid viscosities/waxes withhighliquid liquidviscosities viscosities/waxes viscosities/waxes
Pressuredrop Verylow Verylow Low Low Moderate Low High
Mist Elimination
11
Sulzer KnitMeshTM Wire Mesh Mist Eliminators
SulzerKnitMeshmisteliminatorshaveanexcellenttrackrecordasalowcost,highlyversatileandefficientmethodofremovingliquidentrainmentfromgasstreams.Theyare produced as a bed of knitted meshwhichpresentsatortuouspathandlargesurface area to thedroplets entrained inthe gas stream. Separation is achievedby impingementon, andcaptureby, thefilamentsofthemeshwherethedropletscoalesceanddrain.
Installation can be made in a variety ofways but gas flow is usually either verti-cally upwards, with the liquid drainingcounter-currenttogasflow,orhorizontal,with the liquiddraining inadirectionper-pendiculartothegasflow. Eachmisteliminatoristailor-madetosuit
the dimensions of the vessel or housinginto which it will be installed. Most Knit-Meshwiremeshmisteliminatorsaresup-plied complete with rigid support grids,whichallowdirect installationontoappro-priatesupportssuchasbeamsandringswithin thevessel.Sectional installational-lowseaseofhandlingandaccessthroughvesselmanways.
Accessories such as tie wire, bolting,clamps and support beams can be sup-pliedwherenecessary.
KnitMesh Mist Eliminators
Metal Designs
Material Type Free Density SpecificSurfaceArea Application number volume (lb/ft3) (kg/m3) (ft2/ft3) (m2/m3)Metal 9001 97.5% 12 192 196 643 Veryhighefficiency,verycleanservice 9033 97.5% 12 192 110 350 Heavyduty 9032 97.75% 10.5 170 93 305 Forgeneraluse 9030 98% 9 144 79 258 Standardgeneralpurposemedia 9030-L2 98% 9 144 147 482 Highefficiencyforfineentrainment 9059 98.5% 7 107 109 358 Fineentrainment 9036 98.75% 6 96 52 172 Highvelocity,dirtyservice 4530 98.75% 6 96 52 172 Highvelocity,cleanservice 4540 99% 5 80 44 145 Minimumpressuredrop,dirtyservice
Plastic and Other Materials
GlassWool 9036 93% 12 195 450 1500 Coalescer-veryfinemists 9048 95% 8.25 135 300 1000 CoalescerfinemistsPolypropylene 9008 95% 2.75 45.5 320 1050 Highperformance-acidmists 9030 93% 4.5 74 250 820 Acidmistsandmarineengineintakeswith 9036 95% 2.75 44.5 150 495 minimumpressuredrop 9048 97% 2 41 110 360Multifilament 9033 94% 19 305 340 1115 Finemistconditionswherestainlesssteel(glasswool/ 9030 95% 13.5 215 250 820 canbeallowedandminimumpressuredropstainlesssteel) 9036 96% 9 145 160 525 isimportantFEP 9048 94% 8 128 250 820 HighlycorrosiveconditionsETFE 9048 95% 5.25 85 220 725 Highlycorrosiveconditions
Table B: Standard Sulzer KnitMesh Mist Eliminator Types
Standarddesignsareavailableforroutineapplications, providing excellent separa-tion efficiency down to droplet sizes assmallas2µm,andwithapressuredroptypicallylessthan2.5mbar.Aselectionofstandard styles is described in Table B.Alternatively, we can provide optimizeddesigns to suit specific duties using so-phisticateddesigntools.
Gasoutlet
Gasinlet
Liquidoutlet
SulzerKnitMeshmisteliminator
Schoepentoeter
Gasinlet
Liquidoutlet
SulzerKnitMeshmisteliminator
Gasoutlet
Liquiddrainsperpendiculartodirectionofgasflow
Liquiddrainscounter-currenttogasflow
12
Sulzer KnitMesh V-MISTERTM
ThepatentedSulzerKnitMeshV-MISTER(formerlySulzerKnitMeshVKRMistElimi-nator™)provideshighperformancewher-everliquidentrainmentmustberemovedfromaverticallyflowinggasstream.Misteliminators with Sulzer KnitMesh V-MIS-TER technology employ the mechanismofaVonKarmanRollaroundabluffbody(seeFigure1a) toobtainhighvaporandliquid handling capacity. A vortex devel-opsinalowpressurezonedownstreamofthechannelthathasbeenattachedtothebottomofthemeshpad.Collecteddrop-letsdepositinthetroughandformaflow-ingliquidstreamthere.Contrastthiswiththe standard mesh pad (see Figure 1b)whereatwophase‘fluidized’zoneofgasand liquid develops in the bottom thirdto half of the pad and from which largecoalesced droplets must ultimately draincounter-current to the ascending stream.Thehighcapacitychannelsof theSulzerKnitMesh V-MISTER shield the collectedliquidandthendrain it insteadystreamsfromtwosidesofthemisteliminatoratthecolumnwall,wheregasvelocityissolowthatre-entrainmentislimited.(seeFigure2)
This simple enhancement to a standardmesh pad improves mist elimination be-cause the higher velocities increase thedroplets‘ inertial impactionwiththewiresor filaments. Summarized the V-MISTERcollecting channelsprovide an increasedliquidcapacityofupto300%andahighergasthroughputofupto20%.
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KnitMesh Mist Eliminators
0607 2512-9 0607 2512-10
Fig. 1a Fig. 1b
Fig. 2
Flood
Flood
ConventionalPad V-MISTERPad
Liquidload:1.1m3/m2hr
8
7
6
5
4
3
22.533.544.55
Velocity(m/s)
Pre
ssur
edr
op(m
bar)
8.210121416.4
Velocity(ft/s)
Sulzer KnitMesh XCOAT mist eliminator for a sulfuric acid drying column
The New and Unique Sulzer KnitMesh XCOAT™ Mist Eliminator:The Perfect Solution for Corrosive Services
SulzerhasdevelopedacompletelynewKnitMeshmisteliminatorforcorrosiveservices.TheSulzerKnitMeshXCOATisbasedonametalwirewhichiscoatedwith100%purePTFE.ThisnewmeshmaterialisuniqueandavailableexclusivelythroughSulzer.
SulzerKnitMeshXCOATmisteliminatorsarecharacterizedbyahighdeformation,corro-sionandtemperatureresistance,andarethereforeidealforapplicationswhichhavetodealwithacidssuchassulfuric,aceticandnitricacid.
TheadvantageoflongerservicetimeoftheSulzerKnitMeshXCOATmisteliminatorcom-pared to common wire mesh pads using Teflon filaments or higher alloyed and acid-resistantsteelwireshasbeendemonstratedwithfirstindustrialapplications.
13
High Performance Sulzer KnitMeshTM 9797 Mist Eliminators
TheSulzerKnitMesh9797MistEliminatortechnology provides a means of optimiz-ingdesignstomeetthechallengesofspe-cificapplications.
Unlike ‘industry standard’ mist eliminatordesign methods, which predict perfor-mance using bulk density and filamentdiameter of the separation media, the9797 modeling techniques consider thecharacteristics of individual mesh layersasamathematicalmodelsothattheentireprocesswithintheseparator(capture,co-alescenceanddrainage)canbepredictedonalayerbylayerbasis.ThisenablesSul-zer to produce unique structures wherethe free volumeandmesh freeareacanbe varied through the depth of the pad,givingthebestbalanceofmisteliminator
KnitMesh Mist Eliminators
Liquiddrainstowards
adjacentpore
D1
D2
D4
D5
D3
Fig. 3: The stages of droplet separation on a wire mesh.
An extensive range of mesh styles havebeen analyzed for a variety of processsystems ranging from air/water to morechallenging hydrocarbon conditions. Theperformanceof themisteliminator ises-tablished by calculating the cumulativeeffectofcombinedmesh layersandtheircharacteristics. The model allows a highdegreeofoptimizationsothatlayerspeci-fications can be varied to meet specificprocess challenges. For example, highfreevolume/lowliquidhold-upmaybeanimportantfeatureoftheinletregionofthemisteliminatorwithagradual increase inseparationefficiencytowardstheoutlet.
Existingapplications forSulzerKnitMesh
9797MistEliminatorsinclude:
• glycol contactors – minimization ofTEGentrainmentfromnaturalgasdehy-drationcolumns(seep20).
• gassweetening–installationinamineabsorbers.
• dew-point separators – 9797 designshave helped reduce water and hydro-carbon dew-points in natural gas pro-cessing(seep22).
• rotary screw compressors – reduc-tionofentrainmentofsyntheticoilfromcompressorsystemknock-outdrums.
• steam drums – guaranteed steam dry-nesscanbeachievedusingSulzerKnit-Mesh9797misteliminators.
Fig. 4 represents a bed with N layers ofmesh.
Byassumingthat:
V0 isthevolumeofdropletsentering Layer1
VN isthevolumeofdropletsleaving layerNEi istheindividuallayerefficiency,
thentheoverallefficiencyofthemistelimi-natorcanbeexpressedas:
i=N
VN=V0(1–Ei)
i=1
∏
Dire
ctio
nof
Gas
Flo
w
i=N
i=n+1
i=n
i=n-1
i=2
i=1
Fig. 4
characteristics,suchasliquidhold-upandefficiency,frominlettooutlet.Additionally,separationefficiencycanbepredicted interms of liquid entrainment concentra-tion providing meaningful, measurableinformation on separator performance; aconsiderableimprovementondropletsizeefficiencypredictionswhichareextremelydifficulttoverifyinpractice.
Fig.3 illustratesonelayerofmeshwithinthe mist eliminator and stages of sepa-ration considered by the performancemodel:
• D1avoidscaptureandmovesintothenextlayerofmesh.
• D2iscapturedbythemesh.
• D3 and D4 coalesce to form a biggerdropletorfilm.
• D5drainsfromthemeshsurface.
14
Sulzer MellachevronTM
Mist Eliminators
SulzerMellachevronvanemisteliminatorsare high capacity inertial separators con-structedasbanksofparallel,chevronpro-fileswhichcausethegastochangedirec-tionseveraltimesfrominlettooutlet.Mo-mentumforcesentrainedliquiddropletstoimpingeonthevanesurfaceswheretheyformaliquidfilmanddrain.
TheSulzerMellachevronrange isdividedintoanumberofcategoriesdependingondirectionofgasflowandthecomplexityofthevaneprofile.
SimpleSulzerMellachevronprofilessepa-rate liquid by impingement, coalescenceanddrainageonthevanesurfacewithnodisengagementoftheliquidfromthegasstream. They are particularly suitable forapplicationswithasignificant riskof foul-ingduetosolidparticlesorhighviscosityliquids in the feedbuthave relatively lowgashandlingcapacity.
Mellachevron
Sulzer Mellachevrons are available in various profiles and materials such as stainless steels, alloys or plastics.
Simple Mellachevron profile with countercurrent drainage of liquid from vane surface.
More sophisticated designs provide spe-cial separation channels to allow disen-gagementofliquidanddrainagefromthevanesurface.Thisincreasesthecapacityof the separator andgas load factorsofupto0.45m/sarepossible.Thismakesthemanexcellentchoicewhenequipmentsizeiscritical,forexample,inoffshoreap-plicationsorforde-bottleneckingexistingequipment.
Complex Mellachevron profiles requirehousingswhichensurethatthevanesareassembledaccuratelyandprovidealiquidsumpfordrainageofliquidintothevesselorcolumn.
Drainageslotsonvanesurfaceallowliquidtodisengagefromgasstream
Liquiddrainsinspecialchannelsseparatedfromthegasflow
LiquidcollectsatbottomofdrainagechannelsandmoveslaterallytoMellachevronhous-ingwhereitiscollectedinasumpanddrainedthroughdowncomerpipes
Liquiddrainchannelintegratedinbeam
Liquiddrainchannelintegratedinvanehousing
Removable spacer channel toallowinstallationofthevanes
Jackingbolts
Gas
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Mellachevrondesignsareavailable for in-stallationineitherverticalorhorizontalgasflow.Whengasflow ishorizontal, the liq-uidfilmonthesurfaceofthevanedrainsvertically downwards into a liquid sump.Complex Mellachevron profiles are usedwith hooks or drainage channels whichhelptodisengagetheliquidfromthegasstream and prevent re-entrainment fromthedownstreamface.
Mellachevron
Typical housing arrangement for cross-flow Mellachevron. Sectional installationallows installation and removal throughmanwayandvaneprofilescanbedisman-tledindividuallyforcleaningifnecessary.
Liquidiscollectedinthesumpanddrainedthroughthedowncomerpipeconnection.
Horizontal gas flow arrangement.
0608 2502-6
Table C: Sulzer Mellachevron Mist Eliminator Styles
Mellachevron – Mellachevron – simple vanes Complex profiles with drainage channels
Type C–profile Z-profile CorZ-profilewith Complexprofile-inte- Z-profilewith Z-profilewith largevanespacing graldrainagechannel drainagehooks largevanespacing
Profile
FlowDirection Vertical Vertical Vertical Verticalorhorizontal Horizontal Horizontal
Installation Nohousing Nohousing Nohousing Housinganddrainage Housinganddrainage Housinganddrainage systemrequired. systemrequired. systemrequired.
Gashandling 0.17m/s 0.14m/s 0.14–0.17m/s 0.17–0.45m/s 0.35m/s 0.35m/scapacity(K-values)
Turndown ≈30-50% ≈30-50% ≈30-50% ≈30-50% ≈30-50% ≈30-50%capability
Efficiency Medium Medium–High Low–Medium High Medium Low–Medium downto downto downto downto downto downto ≈30–40µ ≈25µ ≈30–50µ ≈10–15µ ≈25–30µ ≈35–40µ
Liquidload Moderate Moderate High ModeratetoHigh High VeryHighcapacity
Solidshandling ModeratetoHigh Moderate High Low Low LowtoModeratecapability
Liquidviscosity Suitableforhigh Suitableforhigh Verysuitableforhigh Pronetofoulingwith Pronetofoulingwith Suitableforhigh viscosities/waxes viscosities/waxes viscosities/waxes highviscosities/waxes viscosities/waxes viscosities/waxes
Typical Vacuum,general Desalination,general AsforCandZ Debottlenecking,off- Horizontalscrubbers AsforCandZprofilesapplications use,foulingservice use,foulingservice profilesbuthigh shore,cleanservices, buthighfouling/low fouling/low gas&steamprocessing pressuredropservices pressuredrop services
Pressuredrop Verylow Low Verylow Moderate Low Low
Liquiddrainsdownvanesurfacetoasump.
Gas
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Mellachevron
Sulzer Mellachevrons can be installedin a variety of vessel configurations andas arrangement of multiple vane boxesto provide optimum flow and drainagecharacteristicswithin thespaceavailable.TypicalboxandvesselarrangementsareillustratedbelowinFig.5aand5b.
➀
➁
➂
➃
➄
Fig. 5b
1. VerticalFlow
2.Crossflow–Horizontalvessel
3.Crossflow–Two-stageseparator
4.V-bank
5.Crossflow–In-lineseparator
➀
Fig. 5a
DoubleBoxwithKnitMeshPre-conditioner
FourBox V-bank
SulzerMellachevronH45Dcrossflowhighcapacityvanepackforinstallationinadis-chargedrumofanethyleneplant.
Thesophisticatedvaneprofileandintegraldrainage channels of our MellachevronH45D high performance mist eliminatorprovide significant advantages over con-ventionalvanemisteliminators,including:
• reducedpressuredropathighgasloadfactors
• improved liquiddrainagebasedonhol-lowbladeconcept
• upto40%highergasloadcapacity
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Shell SwirltubeTM
TheShellSwirltubeis,inessence,astain-less steel tube with a swirler at the inletandlongitudinalslits inthetubewall.Liq-uidisseparatedbyimpactionofdropletsonthetubewallbythecentrifugalforcesinducedbytheswirlinggasflow.
Re-entrainmentofthisliquidispreventedbydrainingthefilmviatheslitstotheliquidcollection chamber outside the tube. ToensuretheproperfunctioningoftheSwirl-tube it isessential thatsomegas isalsobled through these slits. Thisgas leavesthe liquidcollectionchambervia thesec-ondaryoutletsatthetopoftheSwirldeckassembly.Performancecanbe improvedbyusingasecondaryKnitMeshmistelimi-nator to separate entrainment from thegas leaving the secondary outlets. Themain fractionof thegas leaves theSwirl-tubeviatheprimarygasoutletatthetop.Drainpipesguide the liquid, collected inthespacebetweenthetubesandontheuppercoveroftheSwirldeck,tobelowtheliquidlevel.
Scaling-upofaseparatorequippedwithaSwirldeckisdonesimplybyincreasingthenumberofSwirltubesproportional to thegasflowintheseparator.
Axial Cyclonic Devices
Shell Swirltube LightTM
The Shell Swirltube Light is available asanattractivealternativetovanepacksforhigh capacity bulk separation. The Swirl-tubeLight isbasedon thesophisticatedde-entrainment device used in the ShellConSepTMTray.
Recommendeduse:
•comparableefficiencybuthighercapac-itycomparedtovanepacks.
•operationpossible at higherpressures/lowersurfacetensionsthanvanepacks.
• compact design makes it suitable foroffshore industry or in general for highpressureconditions.
• for debottlenecking of existing separa-tors.
•forhighturndownswithpre-conditioner.(uptofactor10).
• application for slightly fouling serviceandmaybeusedwherecomplexvanesor wire mesh mist eliminators may be-comeplugged.
Swirldeck Swirldeck with secondary KnitMesh
Sec.gas
Liquid
Droplets
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Combined Systems
Increasinggascapacitiesandhigherper-formance requirements in mass transferequipmentarechallengingthecapabilitiesofconventionalmisteliminatorequipment.
Tosolvethis,Sulzerofferscombinedsys-tems which optimize the benefits of indi-vidual types of equipment and improveoverallperformance.
For example, KnitMesh mist eliminatorscan be used in combination with Sul-zer Mellachevron vane packs or Shell
High Capacity Separators with Sulzer Mellachevrons™
Combined Systems
Swirltubes to produce very high separa-tion efficiencies at highgas loadings.Byusing the KnitMesh mist eliminator as apre-conditionerfortheMellachevron,it isoperatedaboveitsnormalre-entrainmentorfloodingpointandconsequently liquidis stripped away from the downstreamsurface.
Theliquiddispersionre-entrainedfromthemesh mist eliminator has a larger meandiameter (See Figure 6) and is suitablefor subsequent separation by secondary,highcapacityequipment.
By analysis of the inlet fluid conditions,Sulzer candesignoptimizedmesh struc-tures to provide the best possible outletconditionsforthedownstreamseparator.
Additional benefits of combined systemsinclude:
• The ability to design the equipment toprovideveryhighturndowncapabilities
• Atlowgasvelocities,wherehighcapac-ityseparatorstendtobeineffective,themesh pre-conditioners behave as con-ventionalmisteliminators
Gas with fine mist
KnitMeshasprimarypreconditioneroper-atesbeyondfloodingpoint
Coalescedlargedropletsfedtosec-ondaryMellachevronmisteliminator
Mist free gas
Coalescedlargedropletseffi-cientlyremovedbyMellachevron
Separatedliquiddrains
Provisionalgap,ifrequired
01020304050Dropsize(µm)
Freq
uenc
y
Vertical flow Separator In-line Separator Two-stage Separator
Mellachevron
KnitMeshPre-conditioner
Downcomerpipe
HighcapacitypackingMellapakPlus
Gasoutlet
Mellachevronmisteliminator
Liquidsump
Gasinlet
KnitMeshPre-condi-tioner
Downcomerpipe
Liquidoutlet
Gasoutlet
Mellachevronmisteliminator
Schoepen-toeter
Liquidsump
Liquidoutlet
KnitMeshPre-condi-tioner
Downcomerpipe
Fig. 6
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0604 2508-8
Combined Systems
Shell High Capacity Separators
Shell proprietary high-capacity gas/liquidseparators,suchasShellSMS™,SVS™,SMSM™ and SMMSM™ separators,combine thebest featuresof thesepara-tionproductsfromSulzer‘sportfolio.Shellgas/liquidseparatorscombineSwirldeck,KnitMesh, and Schoepentoeter separa-tion technologies in a single vertical ves-sel drum. Selection of separation tech-nologiesisfunctionofthedispersedliquidphaseconcentration,dropletsizeandtherequired separation efficiency. Their typi-cal application window is for separationof liquid/gas or three-phase liquid/liquid/gasmixtures,when a high capacity andhigh separation efficiency is required,SMS(M)Technology is the lowestweightandvolumesolutionforphaseseparationoffshore and onshore. It gives up to 2.5timesmorecapacitycompared toacon-ventionalKnitMeshmisteliminatorwithoutvesselreplacement.
Description
ShellSMS,SMSMandSMMSMgas/liquidseparatorsarenamedaftertheconfigurationofthedifferentinternalsusedforeachtypeofseparator:
• SchoepentoeterorSchoepentoeterPlus(S)-usedasfeedinletdeviceforvapordistri-butionwithbulkliquidremoval
• KnitMesh(M)-whichactsascoalescerandseparator,dependingonthegasflowrate
• DoublePrimaryKnitMesh(MM)-speciallydevelopedforapplicationswithtwoimmis-cible liquidphases inthefeedtotheseparators (suchasglycol/condensate inDew-PointSeparators)
• Swirldeck(S)-comprisingmultipleSwirltubes
AsecondKnitMesh(M)isuseddownstreamoftheSwirldeckinSMSMgas/liquidsepara-torsfordemistingsecondarygas.
InfoulingorwaxyservicetheKnitMeshcanbereplacedbyaSulzerMellachevronvanepack(SVSsystems).
100
95
90
8500.10.20.3
Gasloadfactor,m/s
Effi
cien
cy,%
KnitMesh
SMS SMSMSMMSM
Gasloadfactor,ft/s00.330.660.99
Swirldeck
MellachevronVanepack
Schoepentoeter
KnitMesh
Swirldeck
KnitMesh
Schoepentoeter
KnitMesh
Swirldeck
2ndPrimaryKnitMesh
1stPrimaryKnitMesh
Schoepentoeter
SVSSMS/SMSMSMMSM
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Applications
Using Sulzer’s sophisticated KnitMesh 9797 Tech-nology in Glycol Contactors
The first application for Sulzer KnitMesh 9797 mist eliminatorswasforinstallationonanoffshoreplatformintheNorthSea.Therequirement was to control and reduce the glycol entrainment(as liquiddrops) in thegasprior tocompressionandexport. Inoff-shorefacilitiesthe implicationsofentrainmentfromthedehy-drationcolumnsarenotonlyonthevalueoftheglycollost(andre-supply from shore), but also the consequences of admittingthe excess glycol into the gas export pipeline. Not withstand-ingpossibleoperationalproblemsforthepipeline,theincreasedseparationloadattheshoreterminaltoseparategascondensateandglycol,anddisposaloftheglycolphase,aresignificantcosts.The‘industrystandard’figuredefiningthemaximumentrainmentof0.1USgallonsperMMSCFgaswasthereforechallengedandhadtobeimprovedupon.Themisteliminatorsuppliedwiththisapplicationwasshowntosignificantlyreducethefreeglycollossintheexitto<0.05USgallonsperMMSCFgas,afigureverifiedaftermeasurementoftotalglycollossfromthedehydrationunit.
Old FashionedBubbleCaptraysandKnitMesh™misteliminators
State of the ArtMellapak™andKnitMesh™
misteliminatorsincl.thesophisticatedKnitMesh9797type
High Capacity MellapakPlus™andourhigh
capacitymisteliminatorssuchasMKSMultiCassette™,
Mellachevron™,ShellSMS™
The UltimateShellSwirlTube™Trays
andShellSMS™(seealsotheBrochureTraysfor
anyApplications)
Natural Gas Dehydration with TEG
Characteristics
100%capacity
~1.5F-Factor(√ Pa)
Characteristics
190%capacity
>20%moreefficiency
~2.9F-Factor
Characteristics
300%capacity
>20%moreefficiency
~4.5F-Factor
Characteristics
400%capacity
20%moreefficiency
~6.0F-Factor
TEGTEGTEG
NGNG NG
Drygasoutlet
SulzerKnitMesh9797Glycolcontactor
misteliminator
LeanTEG
Chimneytray
Wetgasinlet
Schoepentoeter
Liquidoutlet
Manway
SulzerKnitMesh9798Scrubbersection
misteliminator
RichTEG
SulzerMellapak/MellapakPlus
Liquiddistributor
Manway
TEG
NG
21
Applications
Using Sulzer’s MKS Multi CassetteTM Technology in Glycol ContactorsThefirstapplication forSulzerMKSMultiCassette mist eliminators was for instal-lationinGlycolContactorsinRussia.Thecontactors were revamped from trays toSulzer MellapakPlus and were operatedatveryhighgas loading factors. Inorderto keep the glycol loss low at this highcolumn gas throughput the MKS Multi
Glycol Dehydration Process using Shell SMSM internals in theFeed Inlet Scrubber and MKS Multi Cassette in the Glycol Con-tactor
Highlyefficientliquidscrubbingfromthegasfeedtoglycolcontactorsisneededinor-dertoavoidbottlenecksinthedehydrationsystemcausedbyhydrocarboncarryoverwhichcanleadtofoamingandexcessiveoverallglycollosses.Sulzer’smisteliminationproductssuchasSulzerKnitMesh,SulzerMKSMultiCassetteandShellSeparatorsmeetforthesehighprocessdemands.
Condensate Treatment Unit
ApplicationofSulzer’s liquid/liquidsepa-ratorproductssuchas:
• SulzerMellaplate™platepack
4Cassettesequippedwithstructuredwiredemistingpacking
CollectorTray
SwirlTube
SwirlingElements DrainPipe
VaporisfreeofmistCassettemisteliminatorswereinstalledinthecontactortopsection.Theapplicationwasshowntomeetmeasuredglycolloss-esof<0.1USgallonsperMMSCFgas.
ThepatentedSulzerMKSMultiCassettemist eliminator combines the useful cen-trifugal forces in cyclones with the highseparation efficiency of wire mesh pack-ingstogiveanewsuperiordemistingde-vice.
Vaporcarriesmist
SMS(M)Separator
GlycolContactor
GlycolRegenerator
FlashDrum
•SulzerDCCoalescer™
•SulzerDusec™andDusecPlus™
•SulzerStaticMixers
Glycol Regeneration Unit
Application of Sulzer’s mass transferproducts in the glycol regenerationfacility.
Sulzer MKS Multi Cassette at top of glycol contactor
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SMSInletSeparator
SMMSMExp.SuctionDrum
SMMSMDewPointControlSeparator
FromSlug
Catcher
GlycolInjection
Expander
Compressor
JTValve
ToCompression
SMSCompressor
SuctionDrum
Applications
Low Temperature Separation (LTS) Process
TheperformanceofthegasseparatorsinLTSProcessesiscrucialinordertomeetthehydrocarbonandwaterdewpointspecifications.Thedewpointseparatorisespeciallyessential for the overall performance of the plant. Even small amounts of entrainedliquidswillrapidlyappearasincreaseddewpointinthesalesgas.Toobtainthebestfrom the LTS Process, our high performance Shell SMMSM separator internals areimplementedintheExpanderSuctionDrumandintheDewPointControlSeparator,andShellSMSseparatorinternalsintheInletSeparatorandintheExportCompressorSuctionDrum.
Molecular Sieve Dehydration Process
Theeffectof ahighperformingFeed InletSeparatoron thedeactivation rateof themolecularsievesissubstantial.Thewaterabsorptioncapacitydeterioratesbadlyovertimeastheco-adsorbedhydrocarbonsaccumulateinthemolecularsieve.Sulzerrec-ommendstheuseofadrumwithSchoepentoeterandahighefficiencyKnitMeshmisteliminatorortheShellSMSMseparatorinternalswhenhighcapacityandefficiencyarerequired.
Compressor
MolSieveDriers
FeedInletSeparator
SMSMSeparator
CompressorSuctionDrum
KnitMeshSeparator
FlashGastoFuelGasSystem
Water/HC
DriedGastoLNGUnit
23
Mist Eliminators in Desalination Processes
Desalinationbymulti-stageflashevapora-tionormultipleeffectdistillationunitsisbyfarthemostwidelyusedmethodofgener-atingfreshwaterfrombrineorseawaterintheworld.Itisextremelyreliableandcanproducehighpuritywaterfromalmostallformsoffeed.Theprocessinvolvesevap-orating water from a brine solution andcondensingthevaporasfreshwater.
However, the performance of any flashevaporatorcandeteriorateifliquidentrain-mentiscarriedoverfromtheflashcham-bers into the condenser tube bundles.This isavery likelyoccurrence inviewofthe high velocities and volumetric flow-ratesexperiencedintheseplants,andcanleadtoproblemssuchas:
• Reducedwaterpurity
• Scaling of condenser tube bundle anddownstreamequipmentsuchasboilers
•Corrosionofdownstreamequipment
SulzerMistEliminatorsaredesignedtore-ducetheseproblemsandare installed inmostdesalinationsystems.
Ourexperienceindesalinationhashelpedusdeveloparangeofequipmenttomeetthespecificprocessneedsofourcustom-ers,andgreatcareistakentoensurethattheoptimumdesignisofferedforanypar-ticularduty.Themainfactorstoconsiderindesalinationapplicationsare:
• Efficiency
• Pressuredrop
• Foulingcharacteristicsandthetendencytoscale
• Materialsofconstruction
• Cost
Sulzer KnitMesh Mist EliminatorsSulzer KnitMesh mist eliminators are ide-ally suited to most desalination applica-tions. In multi-stage flash evaporatorsthe mist eliminators are installed directlyabove the flash chambers. Water vaporrises vertically upwards through the misteliminatorandpassesintothecondensertubebundle.Anyentrainedliquiddropletsarecapturedonthewireswheretheyco-alesce and drain, counter-current to thevaporflow,backintotheflashchambers.The separation mechanism is similar tothisinmultipleeffectdistillationsystems.
Thecombinationofhighfreevolumeandspecificsurfaceareameanthatexcellentefficiencies can be achieved for dropletsas small as 5 µm while presenting mini-mumpressuredrop.
Applications
High capacity designsToachievetherequiredcapacity,theevap-oratorsareoftenvery largeand themisteliminatorsusuallycovera largeeffectivefreeareaabove theflashchambers.Thetotalarearequiredisdeterminedbycalcu-lationofthemisteliminatorcapacityandisavery importantpartof theplantdesign.Clearly, any opportunity to reduce thecapitalcostof theevaporators isveryat-tractiveandthecapacityofthemistelimi-nationequipmentisofvitalimportanceinthiscalculation.
Most installations are designed using aconventional K-value of 0.107 m/s butSulzer has developed the high capac-itytype4540NSKnitMeshmisteliminatorwhichcanoperateatupto20%higherK-values,providingtheopportunityforeitherreducedequipmentsizeoranincreasein
capacity. Major projects have been suc-cessfully commissioned using the Sul-zerKnitMesh4540NSmisteliminators inOman,AlgeriaandtheUAE.
Sulzer Mellachevron
Mist EliminatorsPrecipitation of salts and scale on thewiresofKnitMeshmisteliminatorscanbea problem in some plants, particularly inthefirsttwoorthreeeffectsoftheevapo-ration. In these circumstances, the Mel-lachevron Type V20Z has been used toovercometheproblem.Thissimplevaneprofile provides high separation efficien-cy performance for droplets larger than30µm,and itsability towithstandheavyscaling applications makes it an ideal al-ternativetotheKnitMeshmisteliminatorswhenfoulingisofconcern.Itsrobustcon-structionmakesiteasytoclean,andtheMellachevron V20Z also has a relativelylowpressuredropcomparedtothemorecomplexMellachevrondesignswithdrain-agehooksandchannels–animportantfactorwhendesigningforlargevolumetricflowratesatlowpressure.
Steam
Condensatepump
Productpump
Brinepump
Ventejector
KnitMeshorMellachevronMistEliminator
Feedpump
22.84.06.40-IX.12-10-PrintedinSwitzerland
Asia, PacificSulzerChemtechPte.Ltd.10BenoiSector629845SingaporePhone +6565155500Fax +6568627563
Distributedby:
Theactivityprogramcomprises:
• Processcomponentssuchas fractionation trays,structuredand ran-dompackings, liquidandgasdistributors,gas-liquidseparators,andinternalsforseparationcolumns
• Engineeringservices forseparationand reaction technologysuchasconceptualprocessdesign,feasibilitiesstudies,plantoptimizationsin-cludingprocessvalidationinthetestcenter
• Recovery of virtually any solvents used by the pharmaceutical andchemicalindustry,ordifficultseparationsrequiringthecombinationofspecialtechnologies,suchasthinfilm/short-pathevaporation,distilla-tionunderhighvacuum,liquid-liquidextraction,membranetechnologyorcrystallization.
• Complete separation process plants, in particular modular plants(skids)
• Advanced polymerization technology for the production of PLA andEPS
• Tower field services performing tray and packing installation, towermaintenance,welding,andplantturnaroundprojects
• Mixingandreactiontechnologywithstaticmixers
• Cartridge-based metering, mixing and dispensing systems, and dis-posablemixersforreactivemulti-componentmaterial
HeadquartersSulzerChemtechLtdP.O.Box658404Winterthur,SwitzerlandPhone +41522625028Fax [email protected]
North and South AmericaSulzerChemtechUSA,Inc.1SulzerWayTulsa,OK74107,USAPhone +19184466672Fax +19184465321
SulzerChemtechLtd,amemberoftheSulzerCorporation,withheadquar-tersinWinterthur,Switzerland,isactiveinthefieldofprocessengineeringandemployssome3500personsworldwide.
SulzerChemtech is represented inall important industrial countriesandsetsstandards inthefieldofmasstransferandstaticmixingwith itsad-vancedandeconomicalsolutions.
LegalNotice:Theinformationcontainedinthispublicationisbelievedtobeaccurateandreliable,butisnottobeconstruedasimplyinganywarrantyorguaranteeofperformance.SulzerChemtechwaivesanyliabilityandindemnityforeffectsresultingfromitsapplication.