Born, Jens

Ehimen, Ehiazesebhor Augustine

Holm-Nielsen, Jens Bo

Jurgensen, Lars

Rooney, David

    Aalborg UniversitetInfluence of trace substances on methanation catalysts in dynamic biogas upgradingJurgensen, Lars; Ehimen, Ehiazesebhor Augustine; Born, Jens; Holm-Nielsen, Jens Bo;Rooney, DavidPublication date:2014Document VersionPublisher's PDF, also known as Version of recordLink to publication from Aalborg UniversityCitation for published version (APA):Jurgensen, L., Ehimen, E. A., Born, J., Holm-Nielsen, J. B., & Rooney, D. (2014). Influence of trace substanceson methanation catalysts in dynamic biogas upgrading. Poster session presented at ProcessNet-Jahrestagung ,Aachen, Germany.General rightsCopyright and moral rights for the publications made accessible in the public portal are retained by the authors and/or other copyright ownersand it is a condition of accessing publications that users recognise and abide by the legal requirements associated with these rights.            ? Users may download and print one copy of any publication from the public portal for the purpose of private study or research.            ? You may not further distribute the material or use it for any profit-making activity or commercial gain            ? You may freely distribute the URL identifying the publication in the public portal ?Take down policyIf you believe that this document breaches copyright please contact us at vbn@aub.aau.dk providing details, and we will remove access tothe work immediately and investigate your claim.Downloaded from vbn.aau.dk on: April 26, 2017Influence of trace substances on methanationcatalysts in dynamic biogas upgradingLars Jürgensena,b,Ehiaze A Ehimenc , Jens Bornb, Jens Bo Holm-Nielsena, David Rooneyda Dept. of Energy Technology, Aalborg University Esbjerg, Denmarkb Flensburg University of Applied Science, Germanyc Flemish Institute for Technological Research, Belgium, d Queens University Belfast United KingdomKeywordsbiogas, upgrading, Sabatier, surplus electricity,catalyst poisoningIntroductionI Sabatier process-based biogas upgradingfor utilization of surplus electricity producedfrom fluctuating renewable energy.I 650 mostly farm scale biogas plants anda well-developed compressed natural gas(CNG) grid are located near wind farm sites[4].I The Sabatier reaction is catalyzed by Nickelor Ruthenium catalyst and the equilibrium isfar on the right hand site [5,7].:CO2 + 4H2  CH4 + 2H2O ∆H°=-165 kJ/mol.I Carbon formation leads to deactivation bythe considered reactions [1,2]:2CO → CO2 + C (1)CH4 → 2H2 + C (2)CO + H2 → H2O + C (3)CO2 + 2H2 → 2H2O + C (4)I sulfur hydrogen as a trace component is wellknown as poison for Ni catalyst and can beeasily removed by ZnO filters.I There is a lag of studies about the influenceof ammonia on the previously mentioned re-actions and as a catalyst poison.I This study investigate the influence of am-monia as a trace substances of biogas onthe methanation catalystMaterials and MethodsI Experimental setup as shown in Figure 1was used to perform long lasting experi-ments (7 days).I High loaded Ni catalyst was used to provokecoke formation in shorter time (66 %).I 100 mg of pelleted and sieved (fraction be-tween 425µm and 250µm) catalyst wereused in a stainless steel reactor 4 mm in di-ameter.I A stoichiometric feed was used at flow ratesof 20 ml/min.I A saturator containing a 100 mM NH3 solu-tion was used to introduce trace amounts ofNH3 into the feed stream.I GC was used to determine product concen-tration during the whole experiment.I Temperature programmed oxidation (TPO,95 % O2, 5 % Kr as internal standard) wasused to determine carbon formed on the cat-alyst.I The signal S of detected CO2 was standard-ized using the Kr signal S0 as internal stan-dard.Large Scale Bio Energy LabResultsI In all experiments deactivation due to carbon formation had been observed.I The rate of deactivation and the properties of the decomposed coke were influenced by the feedgas composition.I The presence of small amounts of ammonia caused lower deactivation rates and resulted in amore stable system.I In summary, it can be observed that trace NH3 concentrations could convey more positive effectsthan negative, with no pretreatment for NH3 removal from biogas necessary when considering itas a feed gas for methanation processes using Ni catalysts.FiguresCO2 H2 Kr O2MFCMFCMFCMFCTICGCMSventsaturatorfurnacereactorFig. 1: Schematic representation of the experimentalsetup.Fig. 2: Results of TPO for the methanation of "dry"CO2: two different kind of formed carbon were ob-served.Fig. 3: Results of TPO for the methanation of CO2containing small amounts of H2O: the formation of"low temperature coke" is inhibited and the amountof "high temperature coke" is reduced.Fig. 4: Results of TPO for the methanation of CO2containing small amounts of ammonia and H2O: theamount of carbon formed in the process is furtherreduced.AcknowledgmentWe are gratefully acknowledged to the Eu-ropean INTERREG region found that this pa-per and the scientific work had been enabledthrough the project Large Scale Bio Energy Laband to all students and staff working with usduring the project period.Corresponding AuthorLars Jürgensen, M.Sc.Fh FlensburgKanzleistr. 91-93D-24934 FlensburgGermanyphone: 0461 805-1262mail: lars.juergensen@fh-flensburg.dewww.largescale-bioenergy.deReferences[1] Arkatova, LA.: The deposition of cokeduring carbon dioxide reforming of methaneover intermetallides. Catalysis Today,157(1):170-176, 2010.[2] Bartholomew, CH,: Mechanisms of catalystdeactivation. Applied Catalysis A: General,212(1):17-60, 2001.[3] DALLA BETTA , RA., PIKEN, AG., SHELEF,M.: Heterogeneous Methanation: Steady-State Rate of CO Hydrogenation on Sup-ported Ruthenium, Nickel and RheniumJOURNAL OF CATALYSIS 4, 173-183(1975)[4] Hepola, J., Simell, P.: Sulphur poisoning ofnickel-based hot gas cleaning catalysts insynthetic gasifcation gas: Ii. chemisorptionof hydrogen sulphide. Applied Catalysis B:Environmental, 14(3):305-321, 1997.[5] Jürgensen, L., Ehimen, E.A., Born,J., Holm-Nielsen, J.B., Utilization ofsurplus electricity from wind powerfor dynamic biogas upgrading: North-ern Germany case study, Biomassand Bioenergy 66 (2014) 126–132,http://dx.doi.org/10.1016/j.biombioe.2014.02.032[6] MÜLLER K., STÄNDER, M., RACHOW,F., HOFFMANBECK, D., SCHMEISSER,D., Sabatier-based co2-methanation bycatalytic conversion. Environ Earth Sci2013;70(8):3771e8.[7] Navarro, RM., Pena, MA., Fierro, JLP.: Hy-drogen production reactions from carbonfeedstocks: fossil fuels and biomass. Chem-ical Reviews, 107(10):3952-3991, 2007.[8] Twigg M. Catalyst handbook. CSIRO; 1989.

Influence of trace substances on methanation catalysts in dynamic biogas upgrading

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Influence of trace substances on methanation catalysts in dynamic biogas upgrading

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