Ahrenfeldt, Jesper

Gøbel, Benny

Jensen, Torben Kvist

Online Research Database In Technology

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Downloaded from orbit.dtu.dk on: Dec 17, 2017CO Emissions from Gas Engines Fueled by Producer GasAhrenfeldt, Jesper; Jensen, Torben Kvist; Gøbel, BennyPublication date:2002Document VersionPublisher's PDF, also known as Version of recordLink back to DTU OrbitCitation (APA):Ahrenfeldt, J., Jensen, T. K., & Gøbel, B. (2002). CO Emissions from Gas Engines Fueled by Producer Gas[Sound/Visual production (digital)]. Joint IEA and GasNET meeting, Strasbourg, 01/01/2002IEA/GasNet Meeting Fall 2002CO Emissions from Gas EnginesFueled by Producer GasJesper Ahrenfeldt, Torben Kvist Jensen and Benny GøbelBiomass Gasification Group, Technical University of DenmarkBiomass Gasification GroupGasNet Meting Fall 2002 2Agenda• Nature of CO emissions formation in SI gas engines• Experimental measurements • Measurements from the Harboøre plant• CO and global warming • ConclusionBiomass Gasification GroupGasNet Meting Fall 2002 3CO Emissions Formation from SI Gas EnginesBurned Gas Unburned GasFlame FrontGoverning factors:• Air-fuel ratio (λ) • Low combustion-end temperature ⇒ CO+OH→ CO2+H• Low flame speed ⇒ quenching of the flame ⇒ UHC or UCO• Stoiciometric air-fuel ratio: NG=11:1 PG=1:1 Biomass Gasification GroupGasNet Meting Fall 2002 4Data for Test Engines Engine data BUKH NISSAN Bore 85 mm 108 mm Stroke 85 mm 126 mm Compression ratio 12:1 12.5:1 Valve per cylinder 2 2 Intake pressure 0.95 bar 0.70 bar Ignition timing MBT -25 deg Number of cylinders 1 4  Biomass Gasification GroupGasNet Meting Fall 2002 5Gas CompositionsCH4 87.4 [v%]CO2 1.3  [v%]C4H10 1.3 [v%] N2 0.4 [v%]C3H8 3 [v%]C2H6 6.6 [v%]N234.4 [v%]CO220.2 [v%]H2 29.3 [v%]O20.2 [v%]CH41.7 [v%]CO14.1 [v%]Biomass Gasification GroupGasNet Meting Fall 2002 6CO Emissions(Bukh)0100020003000400050006000700080009000100000.8 1 1.2 1.4 1.6 1.8 2 2.2 2.4 2.6λ / [-]CO / [mg/Nm3 @ 5% O2]PGNG•Strong λ dependency•Overall high UCO emissions from PGBiomass Gasification GroupGasNet Meting Fall 2002 7Break Efficiency(Bukh)051015202530351 1.2 1.4 1.6 1.8 2 2.2 2.4 2.6λ [-]η [-]Producer gasNatural gas•Excellent lean burn fuel•Stable operation for 1<λ<3Biomass Gasification GroupGasNet Meting Fall 2002 8Effect of PG Fuel-CO on CO EmissionsFuels:• Natural gas (NG)• Mixture of 50%Vol. NG and 50%Vol. PG (50% PG)• Mixture of 50%Vol. NG and 50%Vol. PG  where the CO content has been replaced by N2 (50% PG-CO).Measurements:• CO emission• UHC emissionBiomass Gasification GroupGasNet Meting Fall 2002 9CO Emissions(Nissan)0300600900120015001 1.2 1.4 1.6 1.8λ / [-]CO / [mg/Nm3 @ 5% O2]NG50% PG50% PG-CORegulation DK• Up to 30% higher CO emissions when fueled by 50% PG compared to NG.• Reduction in emissions when fuel-CO is replaced by N2.• Difference due to UCOBiomass Gasification GroupGasNet Meting Fall 2002 10UHC Emissions(Nissan)02468101 1.2 1.4 1.6 1.8λ [-]UHC / [% of HC in fuel]NG50% PG50% PG-CO• Addition of producer gas increases combustion efficiency at lean conditions.• CO content has no significant influence on combustion efficiency.• For λ>1.6 there is an reduction in UHC emissions of more than 50% compared to NGBiomass Gasification GroupGasNet Meting Fall 2002 11Measurements of PAH and CO emissions for engine #1 at the Harboøre gasification plant in Denmark. Data from Babcock & Wilcox Vølund R&D Centre - august 2001.• High CO emissions• Very low PAH emissions• Catalytic reduction possiblePAH [μg/Nm3, dry] Before ESP After ESP After EngineNaphthalene 37,000 6,300 4.7 Phenanthrene 9,800 <18 1 Benzo(a)pyrene 500 <35 <0.12 TOTAL PAH 68,000-70,000 6,600-6,800 6.4-7.1  λ CO (Before) CO (After) Reduction [-] [ppm] [ppm] [%] 2 1,717 413 76  Measurements from the Harboøre Plant Biomass Gasification GroupGasNet Meting Fall 2002 12CO and Global Warming• CO leads to photochemical production of ozone in the presence of high NOX concentrationsnet: CO+2O2+hv⇒ CO2+O3• For low NOx concentrations CO leads to ozone destructionnet: CO+O3⇒ CO2+O2• O3 has about the same global warming potential (GWP) as CH4Biomass Gasification GroupGasNet Meting Fall 2002 13Conclusion• The high CO emissions from engines fueled by producer gas are mainly due to unburned fuel-CO (UCO)• Combustion efficiency is not influenced by fuel-CO• High CO emissions do not equal high PAH emissions • UCO emissions from producer gas engines are comparable to UHC emissions from natural gas engines, both in origin and in GWP • Separate emissions standards are needed for producer gas engines both for CO and PAH emissions Biomass Gasification GroupGasNet Meting Fall 2002 14Wood GasThe Green Engine Fuel for CHPQuestions ???Biomass Gasification GroupGasNet Meting Fall 2002 15Contact InformationJesper AhrenfeldtPh.D. Student (M.Sc. Eng.)Biomass Gasification Group (BGG)Department of Mechanical EngineeringTechnical University of Denmark (DTU)Phone:     (+45) 4525 4174e-mail:      ja@mek.dtu.dkWeb:        http://www.et.dtu.dk/halmfortetBiomass Gasification GroupGasNet Meting Fall 2002 16Mass Fraction of Fuel Burned(Nissan)00.20.40.60.81-25 0 25 50 75CAD ATDCXbNG50% PG00.20.40.60.81-25 0 25 50 75 100CAD ATDCXbNG50% PGλ=1.7λ=1.1

CO Emissions from Gas Engines Fueled by Producer Gas

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CO Emissions from Gas Engines Fueled by Producer Gas

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