SEPURAN® GreenMembrane technology for upgrading biogas efficiently

Gas separation with SEPURAN®

Evonik, the creative industrial group from Germany, is one of the world leaders in specialty chemicals. As a technology leader in high-performance polymers, we offer hollow-fiber membranes for efficient and energy-saving gas separation. The first product of the SEPURAN® product family is SEPURAN® Green for biogas upgrading.

Benefits

•Lowerenergyconsumption•Noauxiliarymaterialssuchaswater or sorbents required•Noemissionsintotheenvironment•Separationatambienttemperature•Lowspacerequirements•Continuousseparationprocess•Simple,modularsetup•Flexibleandeasilyexpanded•Veryhighselectivity

Applications

•Extractionofmethane•Upgradingofprocessgases •Nitrogengeneration •UpgradingofH2

•Heliumrecovery

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Mode of operation of a membrane cartridge for gas separation

H O HHe CO O N CH

Relative permeation rates of various gases

How does membrane-based separation work?

Gasseparationmembranesworkontheprincipleofselectivepermeationthroughamembranesurface.Thedrivingforcefor permeation of the gas through the membraneisthedifferencebetweenthepartial pressures of the gas on the reten-tateside(theinteriorofthehollowfiber)andthepermeateside(theexteriorofthehollowfiber).

Thegreaterthisdifference,thehigherthe proportion of the gas that permeates throughthemembrane.Inaseparation,suchasbetweencarbondioxideandmethane,permeationofcarbondioxidethrough the membrane is much faster whilemethaneisretainedwithin.

The permeation rate of each gas depends on its solubility in the membrane material andonthediffusionrate.Gasesthathavehigher solubility and smaller molecular

size permeate the membrane faster than larger,lesssolublegases.Theratioofthetransportspeedsoftwogasesiscalledselectivity.

Thehighertheselectivity,thehigherthe energy efficiency of the resulting membrane process. Different membrane materialshavedifferentseparationprop-erties.Thedrivingforcerequiredfortheseparation is obtained through a partial pressure gradient.

Hollow fiber membranes

Permeate

Feed

Fast Slow

Retentate

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Our product – The SEPURAN® Green cartridge

The SEPURAN® product family includes membrane systems for gas separation in various applications. The SEPURAN® Green cartridge is specially designed for biogas upgrading.

TheSEPURAN®Greenmembranecar-tridgeconsistsofseveralthousandhollowfibersmanufacturedfromhigh-performancepolymers and bundled in a stainless steel vessel.Theendsareembeddedinaresin.The membrane cartridge is contained in a closed housing unit.

Themembranesystemcannowwithstandagasmixtureunderpressure.

Many membrane systems can be connected togetherinseriesasdesired,dependingonthe application and the size of the system.Thesimple,easy-to-handleset-uptakesup less space in the upgrading plant.

Thankstotheexcellentselectivityofthemembranes,thecontinuousseparationprocessresultsinveryhighenergyefficiency.

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Cartridge housing

ThesestainlesssteelvesselsfortheSEPURAN®Greencartridgesaremanu-facturedbyexternalpartners,takingindividualnationalrequirementsintoconsideration.

This offers plant engineering companies theadvantageofbeingabletoadaptthe pressure housings to local pressure regulations. Housingsforpressureupto40 bara are available.

Benefits of the cartridge system

•Lowweight•Quickandeconomicmembrane replacement•Flexibilityforhousingdesigns•Costbenefitsincurrentexpenses

SEPURAN® Green cartridges are contained in specially developed housings. The housings are available in different variants to match local requirements.

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SEPURAN® Greenfor biogas upgrading

Production of biogas

Biogasisformedbyfermentationinwhichmicroorganisms anaerobically decompose biomass.Crudebiogascontains55–65%methane,30–45%carbondioxide,andtracegasessuchashydrogensulfide.Af-ter appropriate pretreatment and subse-quentupgradingwithSEPURAN®Green,the biomethane so produced is fed into thenaturalgasgrid,providingconsumerswitheco-friendly,carbon-neutralgas.

Selectivity of SEPURAN® Green

Membrane-based upgrading of biogas exploitsthedifferencesintheperme-abilities of gases through the membranes. SEPURAN®Greenmembraneshavethehighestselectivityandprovideasuperiortechnology for processing of crude biogas.

Biomass from renewable resources

Biomass from (liquid) manure

Biomass from organic waste

Biogas plant

The SEPURAN® product family includes membrane systems for gas separation for various applications. Thanks to its high CO2 over CH4 selectivity, SEPURAN® Green is well suited for biogas upgrading.

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Technical background

Theselectivityofthemembranesisprocess-stable,evenathigherpressureswhicharetypicalintheprocessingofcrude biogas.

ThisiswhereEvonik’smembranesdis-tinguishthemselvesfromotheravailablemembranes.

TheinnovativetechnologywasfirstdemonstratedandtestedatanexistingbiogasplantinNeukirchenanderVöckla,Austriaandhassincebecomeestablishedonthemarket.

Benefits

•Reducedoperatingcosts•Lowinvestment•Simpletooperate•Lowspacerequirementsand short installation times•Canbeusedflexiblyandin modular fashion•Nochemicalsrequired•Noadditionaldryingstep

Natural gas grid

Combined heat and power plant

Filling station

Upgrading

Gas separation Distribution

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SEPURAN® Greenin the biogas plant

Evonik has developed a biogas upgrading process that maximizes the performance of the membranes. By judicious combination of SEPURAN® Green membranes, methane of a purity higher than 99% can be obtained from the crude gas. The only equipment needed is a compressor.

ThebiogasleavesthebiogasplantasamixtureofCO2,methane,andthetypicalby-products.Itisfirstdesulfurizedwithactivecarbon,filtered,andpre-dried.Thepre-cleanedgasisthendrawninwithacompressor,compressedto10–20bar,andupgradedinseveralmembranestagestogivebiomethaneandaCO2-rich off-gas stream. The membrane-based upgrading processdeliversaconsistentlyhighqualityofbiomethanethatisupto99%pure.Further,theoff-gasisverycleanandcon-tainssignificantlylessthan1%methane.Almostallofthemethaneisthusobtainedin natural gas quality.

Benefits

•Lowmethaneslip(loss)of<1% during upgrading•Highmethaneyieldofupto99%, whichmeansmaximumaddedvalue for the operator•Highestenergyefficiencyforupgrading (<0.2kWel/Nm3crudebiogas, <0.4kWel/Nm3biomethane)•Noadditionalancillarymaterialssuch aswaterorsorbents(amines,glycols) arerequired,sonoemissionsintothe environment•Easilyregulatedforchangesinflow rate or composition •Followingtheupgradingprocesswith membranes,thebiomethaneisalready dryandsatisfiesthedew-point requirement for feeding into the grid•Easilyscalable;canbeusedforsmall plants(10Nm3/h)aswellaslarge (>1000Nm³/h)•Startingandstoppingoftheplantis possibleatshortintervals,ensuring highflexibility;thereforeideallysuited foroperationofabiomethanefilling station at the site•Directfeeding(viaatransmission pipeline)intothenaturalgasgridis possiblewithoutanadditional compressor

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Evonik pilot plant

From2011to2014EvonikoperatedapilotplantinNeukirchenanderVöckla,Austria,totestthenewlydevelopedup-gradingprocesswithSEPURAN®Greenmembranes.

Our products and services

WeofferSEPURAN®Greenmembranetechnologyanddevelopesuperiorprocesssolutions for your biogas separation re-quirementsjointlywithpartnersinplantengineering.

•SEPURAN®Greencartridges•Processdesignformembrane-based biogas upgrading•Weworkinconjunctionwithknowl- edgeable plant-engineering companies tooffersystemsolutionsonthemarket.

Crude biogas from the fermenter, approx. 53% methane, 47% CO2

Compressor10 - 20 bar

Product streambiomethane (>99%)10 - 20 bar

Off-gas, predominantly CO2 with <1% methane

Connection of SEPURAN® Green

membranes

Reverse stream

Gas content remains stable in the long term

Gas

cont

ent[

%]

CH4 off -gas CH4 product gas CH4 in crude gas CO2 in crude gas

0 100 200 300 400 6000 6500 7000 7500 8000 8500Time[h]

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SEPURAN® Green – Our references worldwide

Biogas upgrading facilities* with SEPURAN® Green

Size[Nm3/h]

Country Quantity 1-199 200 - 499 500-999 >1000Austria 3 China 2 Denmark 2 France 11 Germany 13 Italy 1 Japan 1 Korea 2 Netherlands 6 Norway 1 Sweden 2 Switzerland 8 Thailand 2 UnitedKingdom 23

*Operatingplantsandplantsunderconstruction

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IcknieldFarm,Ipsden(Oxfordshire),UnitedKingdom350Nm³/h

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®registeredtrademarkThisinformationandanyrecommendations,techni-calorotherwise,arepresentedingoodfaithandbe-lievedtobecorrectasofthedateprepared.Recipi-ents of this information and recommendations must maketheirowndeterminationastoitssuitabilityfortheirpurposes.InnoeventshallEvonikassumeliabil-ityfordamagesorlossesofanykindornaturethatresult from the use of or reliance upon this informa-tionandrecommendations.EVONIKEXPRESSLYDISCLAIMSANYREPRESENTATIONSANDWAR-RANTIESOFANYKIND,WHETHEREXPRESSORIMPLIED,ASTOTHEACCURACY,COMPLETE-NESS,NON-INFRINGEMENT,MERCHANTABILI-TYAND/ORFITNESSFORAPARTICULARPUR-POSE(EVENIFEVONIKISAWAREOFSUCHPURPOSE)WITHRESPECTTOANYINFORMA-TIONANDRECOMMENDATIONSPROVIDED.Referencetoanytradenamesusedbyothercompa-nies is neither a recommendation nor an endorse-mentofthecorrespondingproduct,anddoesnotim-plythatsimilarproductscouldnotbeused.Evonikreservestherighttomakeanychangestotheinfor-mationand/orrecommendationsatanytime,with-out prior or subsequent notice.

Evonik Fibres GmbHGewerbepark4 4861SchörflingAustriaphone +43 7672 701-2891fax +43 7672 96862www.sepuran.comsepuran@evonik.com