frOM BiOgas tO grEEN gasUpgrading techniques and suppliersBiogas is produced by fermenting plants such as crop residues, liquid residues and maize, often in combination with animal manure. it is usually used to generate electricity. However, there is a more sustainable and profitable option: to upgrade the biogas and inject it into the national gas grid. Biogas that has been upgraded to natural-gas quality is known as ‘green gas’.

TheDutchgovernment(CabinetBalkenendeIV)andotherEU

MemberStateshavesetambitioustargetsformakingenergy

suppliesmoresustainable.TheDutchgoalistoachieve20%

sustainableenergyby2020.Makingthegassupplymore

sustainablecanmakeanimportantcontributiontothistarget.

around 10% green gas in 2020

Thepre-conditionsarepresent:greengascanbecertified(justlike

greenelectricity)andthereisfinancialsupportavailableviathe

SDEscheme(anincentiveschemeforsustainableenergy

production).Initsvisiondocument‘Let’sgivefullgas!’theGreen

Gasworkinggroupstatesatargetof8–12%natural-gas

replacementbytheyear2020.ThistargetisincludedintheEnergy

InnovationAgenda,asoneofthesubjectsthattheDutchCabinet

planstofocusonoverthenextfewyears.

green gas based on fermentation

Greengascanbeproducedintwoways:byupgradingbiogas(from

fermentationofwetbiomass)tonatural-gasquality,orby

gasificationofbiomass.Thisbrochureexplainsgreengas

productionbasedonfermentation,detailsexampleprojectsand

listssuppliersoftheseinstallations.

upgraDiNg BiOgas

increasing methane levels...rhogen...

When upgrading biogas to green gas

the energy content is increased until

the Wobbe-index is equal to that of

natural gas. A higher methane content

is achieved by extracting the CO2

from the biogas.

...and cleaning

Siloxanes (organic materials, such as

chlorine, sulphur etc.) also need to be

removed in a pre-treatment or post-

treatment process. Cleaning is

important in order to prevent air

pollution, contamination of surface

water, as well as pollution of engines,

for example.

From biogas to green gas: upgrading techniques

gas cleaning cryogenic techniques Vpsa membrane Filtration

Liquid absorbs CO2 Separating liquid CO2 Active carbon adsorbs CO2Separating CO2 via a membrane

Dutch suppliers •Cirmac(LPCooab-technique)

•DMT(TS-PWSprocess)• See also De Marke project*

• GTS(GPP-technique) •Cirmac(VPSA=vacuumswingadsorption)

• Cirmac• Van der Wiel Stortgas

Methane loss (without using residue gas)

<0.1%(Cirmac)<1%(DMT)

<0,5% 1–3%*** 15–20%****

Methane contentproduct gas

max.99,5%(Cirmac)max.98%(DMT)

max.99,5% max.98% max.90%

Working pressure atmospheric(Cirmac)8–10bar(DMT)

10–18bar 6–8bar 6–8bar

Electricity consumption

0,05–0,12**kWe/Nm3rawgas(Cirmac)0,20–0,25kWe/Nm3rawgas(DMT)

0,20–0,28kWe/Nm3rawgas 0,25kWe/Nm3rawgas 0,20kWe/Nm3rawgas

Comments CO2-exhaustgascanbeutilisedusefully

PureCO2(liquid)asusefulby-product

Equipmentiscompact,simpleandlightweight

Theaforementionedfiguresareindicationsonly,basedoninformationprovidedbythesuppliers.*Thisdemonstrationproject(seebackpage)usedathirdgasscrubbingtechnique,developedbyTNO,TechnoInventandLTONoord.**0.05kWe/Nm3appliesifcompressionisnotnecessary(suchaswheninjectingintothe100mbarlow-pressuregrid).Theenergyconsumption

increasesifcompressionisusedtoinjectathigherpressures.Heatisalsonecessarytoregeneratetheabsorptionsubstance.Theadvantageofmuchlowerenergyconsumptionthereforeonlyremainsifthereisresidualheatavailable.

***Upto3%ofthe(stronggreenhousegas)methaneendsupintheresidualgas.Thismethaneemissionmaynotbeacceptabletocompetentauthoritiesthatissuepermits,soadditionalmeasuresmayberequired.

****Withmembranetechnology(andfromanefficiencypointofview),thepermeategasshouldbeusedtogenerateenergy.

upgraDiNg tEcHNiquEs

Iftheplantcapacityisover2000Nm3perhour,thenmembrane

filtrationislesseconomicallyviable.Ifresidualheatisavailable

atthelocation,thisisanextrapluspointforaminegascleaning

(CirmacLPCooab),becausethisresultsinextremelylow

electricityconsumption.Onlythecryogenictechniqueproduces

industrial-qualityliquidCO2.(Seetableforfurtherdetails.)

costs

Inordertomakeacorrectcomparisonofinvestmentand

operationcosts,thenecessarycostsforpre/posttreatmentalso

needtobetakenintoconsideration,aswellasthesavingsin

usefulutilisationofresidues.Pricecomparisonsofthe‘basic

installation’usuallygiveafalsepicture,becauseonesupplier

integratesallprocessstagesintoasingleinstallation,and

anothertakesadifferentapproach.Inareportpublishedatthe

endof2008theGermanFraunhoferUMSICHTcomparedgas

scrubbingandPSAtechniquesofvariousmanufacturers,

includingCirmac.Theinvestmentcostsofa500Nm3capacity

plantwerearoundonemillioneuro.Thescaleadvantagesare

considerable,particularlywhenscalingupfrom250to500

Nm3.Forfurtherdetailsthisreportcanbeobtainedfromthe

secretaryoftheCommitteeforGreenGas.

Wstp Mijdrecht

Upgrading technique:

Gas cleaning (LP cooab technique)

Equipment supplier:

BioGast, using cirmac technique

The Waternet wastewater sewage

treatment plant has produced green gas

since the end of 2008. Around 280,000

Nm3 of biogas are upgraded annually, into

205,000 Nm3 of green gas. This amounts

to 30 Nm3 of green gas per hour. The green

gas is then injected into the natural gas

grid (Stedin) and used as a transport fuel.

PRojecT

Determining which is the best, most efficient upgrading technique for a particular situation depends on so many factors that this can only be decided on an individual basis. However, a few initial guidelines can be given.

suppliErscirmac international Cirmachasspecialisedinbiogasupgradingsystemsforover

20years.Thecompany’sLPCooab-technology(CO2absorptionbyanamine)hasless

than0.1%methaneloss,verylowelectricityconsumption,andhighenergyefficiency.

Ausefulbyproduct:pureCO2gas.Exhaust-gastreatmentisnotnecessary.The

processworksonatmosphericpressureandiseasilycontrolled:thesupplypressure

canbechangedeasily.Increasedpressuredoesrequiremoreelectricity.Cirmac

systemsarebeingoperatedbothinsideandoutsidetheNetherlands,withcapacities

rangingbetween160and1600Nm3perhour.Systemswithcapacitiesof60–3450

Nm3perhourarenowbeingbuilt,whichshowthatCirmacsystemsare

economicallyviableatvariousscalesizes.

gas treatment services (gts) Thiscompanymanufacturesaninnovative

cryogenictechniquethatupgradesbiogastonatural-gasqualityandalso

producesindustrial-qualityliquidCO2.Thiscanbeusedincommercial

greenhouses,beerbreweriesetc.Thesystemconsistsoffourstages:

(1)gascompression,

(2)gasdrying,removingpollution,followedbycoolingto-25°C,

(3)furthergascleaningwithacatalyticfilter,

(4)CO2removalandupgradingtotherequiredquality.

SincegascleaningandCO2extractionarecombined,itisnotnecessarytoremovethesulphurbeforehand.

Methanelossesarelow:max.0.5%.GTSsuppliesstandardsystemsthatcancopewith50–2500Nm3biogasperhour.

DMt Environmental technology DMTisamemberoftheCoalitionforDrivingon

Biogas,andhasspecialisedindesulphurisationandupgradingprocessesforbiogas

forover20years.TheTS-PWSprocessusedbyDMTisafurtherdevelopmentofthe

PWS(pressurewaterscrubber)technology.Thisprocesshasbeendevelopedinorder

toremoveCO2,hydrogensulphide,ammonia,higherhydrocarbonsandsiloxanes,

andtominimisewasteresidues.Gasisdriedandbroughtuptoapressureof8–10

bar.Theonlyresidue:airwithahighconcentrationofCO2.Thiscanbeusedin

commercialhorticulturalgreenhouses.Capacitiesof100–5000Nm3perhourare

possible.Theequipmentiscompactandisconstructed(onamodularbasis)in

shippingcontainers.

Van der Wiel stortgas Thiscompanyoffersawiderangeof

solutionsandservicesregardingenvironmentaltechniques.

Inordertoupgradebiogastonatural-gasquality,VanderWiel

suppliesequipmentthatcancopewithaninputof200–3000

Nm3perhour.

CO2isremovedatlowpressureusingmembranefilters–thisis

adryprocessthatusesnochemicals.Contaminationby

sulphur,fluoridesandchlorineisremovedfromthegasusing

activecarbon.Thecompleteinstallationismountedona

galvanisedsteelskid.Thecontrolsystemisbuiltintoan

insulatedandventilatedroom.VanderWielsuppliesthree

standardunitswithamaximuminputof400,800or1200Nm3

perhour,forbiogaswithlessthan8%nitrogenandlessthan

100ppmsulphur.

Bergerden horticultural area

Upgrading technique:

cryogenic

Equipment supplier:

GTs

Arable farmers in the horticultural area

between Arnhem and Nijmegen have set

up an association known as the Bio

Energie Bergerden (BEB). This company

plans to produce biogas by fermenting

around 36,000 tons of biomass per year,

half of which is manure. The residues from

the fermentation process can be used as

organic fertiliser.

Green gas

The aim is to inject 5 million Nm3 of green gas per

year into the local natural-gas grid. During the winter,

production of 600 Nm3 per hour covers one-fifth of

the need and can even be fully sold during the

summer months, when less heating is required.

industrial-quality liquid co2

The biogas, with 50 – 60% methane, is upgraded into

green gas. The cryogenic technique releases clean

liquid CO2 that can be used in the food industry and as

crop-enhancing gas in the horticultural areas. The

process heat and electricity (cogeneration) required

will be derived from the area itself.

Plans

BEB hopes to start producing green gas in 2009. The

installation has been sized such that production can

be expanded considerably, as required. Other green

gas products, such as LBG (liquid biogas) are also

being considered.

PRojecT

PRojecTThe wastewater sewage treatment plant operated by the Hoogheemraadschap

Hollands Noorderkwartier (HHNK) upgrades 1.4 million Nm3 of biogas into 650,000

Nm3 of green gas on an annual basis. This is 80 – 100 Nm3 of green gas per hour.

The methane content in the biogas is 62%, and 89% in the product gas. The

permeate gas is used to heat the fermenter. The green gas is injected into the

natural gas grid (Stedin) and used for transport.

Wstp Beverwijk

Upgrading technique:

membrane filtration

Equipment supplier:

BioGast

using cirmac technology

Natuurgas Overijssel

Upgrading technique:

gas cleaning

Natuurgas Overijssel, a cluster of waste organisations ROVA and HVC Groep,

process 30,000 tons of household compostable waste into 12,000 tons of

compost and over 3 million Nm3 of biogas, with a methane content of

50 – 70%. The gas upgrade equipment processes the biogas into natural-gas

quality at a rate of 400 Nm3 per hour.

Project ‘Rijden op GFT ‘ (driving on compostable waste)

As part of this project, a number of vehicles demonstrate driving on green gas.

Vehicles were selected that had been fitted with natural-gas engines by the

manufacturer. Cars, delivery vans and buses, as well as the most modern

dustcarts and street-cleaning machines can also run on gas. In Zwolle, a public

filling station has been fitted with a refuelling point for green gas. The project

is financed by Natuurgas Overijssel, Salland Oil and the province of Overijssel.

Groen gas in natural-gas grid

At the beginning of 2009, Natuurgas Overijssel, Gasunie and Enexis signed a

collaboration agreement to implement a demonstration project. A new pipeline

(8 bar) will transport green gas to a compressor, from where it will be injected into

the high-pressure (40 bar) grid run by Gasunie. The supply of green gas to clients

will be based on a certification system, such as also exists for green electricity.

The province of Overijssel and Gasterra also contribute to this project.

ReseaRch inTo

eFFiciency

The installation includes a range

of facilities to minimise micro-

organisms and other substances.

The gas is eventually passed

through a HEPA filter (this type

of filter is also used in hospitals).

Part of the project objectives are

to study whether or not these

extra measures are really

necessary, and how risk

minimisation can be achieved

more efficiently and

economically in the future.

PRojecT

Experimental farm: De Marke

Upgrade technique:

gas cleaning

Equipment supplier:

Tno/Techno invent/LTo noord

Using a technology developed by TNO

(among others), the plant at De Marke

processes biogas into gas that

contains over 95% methane, which

is ideal for use as a transport fuel.

Natural-gas quality is achieved by

adding nitrogen. The equipment is

compact (2.5 x 2.5 x 4.5 m) with a

capacity of 500 Nm3 per hour, and is

entirely automatic. It is profitable at

capacities of 50 – 500 Nm3 per hour.

Methane losses are less than 0.5%.

Tno desulphurisation technology

In a single simple cleaning step, all

pollutants (CO2, hydrogen sulphide,

ammonia and silanes) are removed

from the biogas. The TNO-developed

desulphurisation technology forms

the basis for the system. The resulting

sulphur slurry is reinjected into the

digestate, and used as fertiliser.

For natural-gas grid and tractors

The green gas contains less than 1 ppm

of hydrogen sulphide, which is well

below the maximum of 3 ppm that the

Gasunie has set for injection into the

gas grid. The green gas is injected into

the regional gas grid at De Marke

(Liander) and is used for tractors.

PRojecT BiOgas upgraDiNg iN BriEfWho benefits from upgrading biogas?

• Farmersandmarketgardeners

• Thefoodandluxuryfoodindustry

• Wasteprocessors

• Transportsector

• Projectdevelopersandinvestors

• Authorities,especiallyprovincialauthorities

Where is biogas produced?

• Atco-fermentationplantsintheagriculturalsector

• Atfermentationplantsbasedonwastestreamsfromthefood

andluxuryfoodindustry

• Atwaterpurificationplantswithsludgefermentation

• Attheexistinglandfillrefusesiteswherelandfillgasis

upgraded

What are the advantages of upgrading to green gas?

• Noenergyislostintheformofheat,whichisalmostalways

thecasewhenelectricityisproducedfrombiogas

• Greengascanbetransportedviathenatural-gasgridand

usedinvehicleswithnatural-gasengines

Which companies in the Netherlands provide the necessary

technology?

• BioGast:www.biogast.nl

• CertifiedEnergy:www.certified-energy.nl

• CirmacInternational:www.cirmac.com

• DMTEnvironmentalTechnology:www.dmt-et.nl

• GastreatmentServices:www.gastreatmentservices.com

• VanderWielStortgas:www.vanderwiel.nl

Thislistisnotexhaustive.

further information

NewGasPlatform

CommitteeforGreenGas

Mr.M.H.M.(Mathieu)Dumont,secretary

t+31-(0)302393790

em.dumont@senternovem.nl

enieuwgas@senternovem.nl

www.creatieve-energie.nl

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