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Gas Liquid Separation Technology

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Gas/Liquid Separation Technology Sulzer Chemtech
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Page 1: Gas Liquid Separation Technology

Gas/Liquid Separation Technology

Sulzer Chemtech

Page 2: Gas Liquid Separation Technology

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.

Page 3: Gas Liquid Separation Technology

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.

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Page 4: Gas Liquid Separation Technology

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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Page 5: Gas Liquid Separation Technology

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

0608 2502-6

0604 2512

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Page 6: Gas Liquid Separation Technology

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

0600 2505-3

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Page 7: Gas Liquid Separation Technology

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

Page 8: Gas Liquid Separation Technology

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

Page 9: Gas Liquid Separation Technology

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

0607 2510 11

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.

Page 10: Gas Liquid Separation Technology

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

Page 11: Gas Liquid Separation Technology

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

Page 12: Gas Liquid Separation Technology

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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%.

0607 2512 -2

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.

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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.

Page 14: Gas Liquid Separation Technology

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

Page 15: Gas Liquid Separation Technology

15

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

Page 16: Gas Liquid Separation Technology

16

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.

Fig. 5b

1. VerticalFlow

2.Crossflow–Horizontalvessel

3.Crossflow–Two-stageseparator

4.V-bank

5.Crossflow–In-lineseparator

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

Page 17: Gas Liquid Separation Technology

17

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

Page 18: Gas Liquid Separation Technology

18

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

Page 19: Gas Liquid Separation Technology

19

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

Page 20: Gas Liquid Separation Technology

20

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

Page 21: Gas Liquid Separation Technology

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

Page 22: Gas Liquid Separation Technology

22

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

Page 23: Gas Liquid Separation Technology

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

Page 24: Gas Liquid Separation Technology

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.


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