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  • 1.
    Hedström, Lars
    KTH, School of Chemical Science and Engineering (CHE), Chemical Engineering and Technology, Energy Processes.
    Fuel Cells and Biogas2010Doctoral thesis, comprehensive summary (Other academic)
    Abstract [en]

    This thesis concerns biogas-operated fuel cells. Fuel cell technology may contribute to more efficient energy use, reduce emissions and also perhaps revolutionize current energy systems. The technology is, however, still immature and has not yet been implemented as dominant in any application or niche market. Research and development is currently being carried out to investigate whether fuel cells can live up to their full potential and to further advance the technology. The research of thesis contributes by exploring the potential of using fuel cells as energy converters of biogas to electricity.

    The work includes results from four different experimental test facilities and concerns experiments performed at cell, stack and fuel cell system levels. The studies on cell and stack level have focused on the influence of CO, CO2 and air bleed on the current distribution during transient operation. The dynamic response has been evaluated on a single cell, a segmented cell and at stack level. Two fuel cell systems, a 4 kW PEFC system and a 5 kW SOFC system have been operated on upgraded biogas.

    A significant outcome is that the possibility of operating both PEFCs and SOFCs on biogas has been established. No interruptions or rapid performance loss could be associated with the upgraded biogas during operation. From the studies at cell and stack level, it is clear that CO causes significant changes in the current distribution in a PEFC; air bleed may recover the uneven current distribution and also the drop in cell voltage due to CO and CO2 poisoning. The recovery of cell performance during air bleed occurs evenly over the electrode surface even when the O2 partial pressure is far too low to fully recover the CO poisoning. The O2 supplied to the anode reacts on the anode catalyst and no O2 was measured at the cell outlet for air bleed levels up to 5 %.

    Reformed biogas and other gases with high CO2 content are thus, from dilution and CO-poisoning perspectives, suitable for PEFC systems. The present work has enhanced our understanding of biogas-operated fuel cells and will serve as basis for future studies.

  • 2.
    Hedström, Lars
    et al.
    KTH, School of Chemical Science and Engineering (CHE), Chemical Engineering and Technology.
    Holmström, Nicklas
    KTH, School of Chemical Science and Engineering (CHE), Chemical Engineering and Technology.
    Saxe, Maria
    KTH, School of Chemical Science and Engineering (CHE), Chemical Engineering and Technology.
    Alvfors, Per
    KTH, School of Chemical Science and Engineering (CHE), Chemical Engineering and Technology.
    Ridell, Bengt
    Rissanen, Markku
    Lindbergh, Göran
    KTH, School of Chemical Science and Engineering (CHE), Chemical Engineering and Technology.
    Operating Experience and Results from 3310 hours of Operation of a Biogas-powered 5 kW SOFC System in GlashusEttManuscript (preprint) (Other academic)
  • 3.
    Hedström, Lars
    et al.
    KTH, School of Chemical Science and Engineering (CHE), Chemical Engineering and Technology, Energy Processes.
    Saxe, Maria
    KTH, School of Chemical Science and Engineering (CHE), Chemical Engineering and Technology, Energy Processes.
    Folkesson, Anders
    KTH, School of Chemical Science and Engineering (CHE), Chemical Engineering and Technology, Energy Processes.
    Wallmark, Cecilia
    KTH, School of Chemical Science and Engineering (CHE), Chemical Engineering and Technology, Energy Processes.
    Haraldsson, Kristina
    KTH, School of Chemical Science and Engineering (CHE), Chemical Engineering and Technology, Energy Processes.
    Bryngelsson, Mårten
    KTH, School of Chemical Science and Engineering (CHE), Chemical Engineering and Technology, Energy Processes.
    Alvfors, Per
    KTH, School of Chemical Science and Engineering (CHE), Chemical Engineering and Technology, Energy Processes.
    Key factors in planning a sustainable energy future including hydrogen and fuel cells2006In: Bulletin of Science, Technology & Society, ISSN 0270-4676, E-ISSN 1552-4183, Vol. 26, no 4, p. 264-277Article in journal (Refereed)
    Abstract [en]

    In this article, a number of future energy visions, especiallythose basing the energy systems on hydrogen, are discussed.Some often missing comparisons between alternatives, from asustainability perspective, are identified and then performedfor energy storage, energy transportation, and energy use invehicles. It is shown that it is important to be aware of thelosses implied by production, packaging, distribution, storage,and end-use of hydrogen when suggesting a "hydrogen economy."It is also shown that for stationary electric energy storage,fuel cell electrolyzers could be feasible. Zero-tailpipeemissionvehicles are compared. The battery electric vehicle has thehighest electrical efficiency, but other requirements implythat plug-in hybrids or fuel cell hybrids might be a betteroption in some types of vehicles. Finally, a simplified exampleis applied to the overall results and used to discuss the needsand nature of an energy system based on intermittent energysources. 

  • 4.
    Hedström, Lars
    et al.
    KTH, School of Chemical Science and Engineering (CHE), Chemical Engineering and Technology.
    Tingelöf, Thomas
    KTH, School of Chemical Science and Engineering (CHE), Chemical Engineering and Technology.
    Alvfors, Per
    KTH, School of Chemical Science and Engineering (CHE), Chemical Engineering and Technology.
    Lindbergh, Göran
    KTH, School of Chemical Science and Engineering (CHE), Chemical Engineering and Technology.
    Experimental results from a 5 kW PEM fuel cell stackoperated on simulated reformate from highly dilutedhydrocarbon fuels: Efficiency, dilution, fuel utilisation,CO poisoning and design criteria2009In: International journal of hydrogen energy, ISSN 0360-3199, E-ISSN 1879-3487, no 34, p. 1508-1514Article in journal (Refereed)
    Abstract [en]

    The present article analyses the effects of dilute biogas on efficiency, fuel utilisation, dynamics, control strategy, and design criteria for a polymer electrolyte fuel cell (PEFC) system. The tested fuel compositions are exemplified by gas compositions that could be attained within various Swedish biofuel demonstration projects. Experimental data which can serve as a basis for design of PEFC biogas systems operating in load-following, or steady-state mode, are reported for a 5 kW PEFC stack.

  • 5.
    Hedström, Lars
    et al.
    KTH, Superseded Departments, Chemical Engineering and Technology.
    Wallmark, Cecilia
    KTH, Superseded Departments, Chemical Engineering and Technology.
    Alvfors, Per
    KTH, Superseded Departments, Chemical Engineering and Technology.
    Rissanen, Markku
    Stridh, Bengt
    Ekman, Josefin
    Description and modelling of the solar–hydrogen–biogas-fuel cell system in GlashusEtt2004In: Journal of Power Sources, ISSN 0378-7753, E-ISSN 1873-2755, no 131, p. 340-350Article in journal (Refereed)
    Abstract [en]

    The need to reduce pollutant emissions and utilise the world's available energy resources more efficiently has led to increased attention towards e.g. fuel cells, but also to other alternative energy solutions. In order to further understand and evaluate the prerequisites for sustainable and energy-saving systems, ABB and Fortum have equipped an environmental information centre, located in Hammarby Sjostad, Stockholm, Sweden, with an alternative energy system. The system is being used to demonstrate and evaluate how a system based on fuel cells and solar cells can function as a complement to existing electricity and heat production. The stationary energy system is situated on the top level of a three-floor glass building and is open to the public. The alternative energy system consists of a fuel cell system, a photovoltaic (PV) cell array, an electrolyser, hydrogen storage tanks, a biogas burner, dc/ac inverters, heat exchangers and an accumulator tank. The fuel cell system includes a reformer and a polymer electrolyte fuel cell (PEFC) with a maximum rated electrical output of 4 kW(el) and a maximum thermal output of 6.5 kW(th). The fuel cell stack can be operated with reformed biogas, or directly using hydrogen produced by the electrolyser. The cell stack in the electrolyser consists of proton exchange membrane (PEM) cells. To evaluate different automatic control strategies for the system, a simplified dynamic model has been developed in MATLAB Simulink. The model based on measurement data taken from the actual system. The evaluation is based on demand curves, investment costs, electricity prices and irradiation. Evaluation criteria included in the model are electrical and total efficiencies as well as economic parameters.

  • 6.
    Saxe, Maria
    et al.
    KTH, School of Chemical Science and Engineering (CHE), Chemical Engineering and Technology.
    Hedström, Lars
    KTH, School of Chemical Science and Engineering (CHE), Chemical Engineering and Technology.
    Rissanen, Markku
    ABB AB, Corporate Research.
    Lindbergh, Göran
    KTH, School of Chemical Science and Engineering (CHE), Chemical Engineering and Technology.
    Alvfors, Per
    KTH, School of Chemical Science and Engineering (CHE), Chemical Engineering and Technology.
    Ridell, Bengt
    Grontmij AB, Energy Systems.
    Operating experience and energy system analysis of the biogas-powered 5 kW SOFC system in GlashusEtt2008In: Proceedings of the WREC X conference, 2008Conference paper (Refereed)
  • 7.
    Tingelöf, Thomas
    et al.
    KTH, School of Chemical Science and Engineering (CHE), Chemical Engineering and Technology.
    Hedström, Lars
    KTH, School of Chemical Science and Engineering (CHE), Chemical Engineering and Technology.
    Holmström, Nicklas
    KTH, School of Chemical Science and Engineering (CHE), Chemical Engineering and Technology.
    Alvfors, Per
    KTH, School of Chemical Science and Engineering (CHE), Chemical Engineering and Technology.
    Lindbergh, Göran
    KTH, School of Chemical Science and Engineering (CHE), Chemical Engineering and Technology.
    The influence of CO2, CO and air bleed on the current distribution of a polymer electrolyte fuel cell2008In: International journal of hydrogen energy, ISSN 0360-3199, E-ISSN 1879-3487, no 33, p. 2064-2072Article in journal (Refereed)
    Abstract [en]

    The influence of CO2, CO and air bleed on current distribution was studied during transient operation, and the dynamic response of the fuel cell was evaluated. CO causes significant changes in the current distribution in a polymer electrolyte fuel cell. The current distribution reaches steady state after approximately 60 min following addition of 10 ppm CO to the anode fuel stream. Air bleed may recover the uneven current distribution caused by CO and also the drop in cell voltage due to CO and CO2 poisoning. The recovery of cell performance during air bleed occurs evenly over the electrode surface even when the O-2 partial pressure is far too low to fully recover the CO poisoning. The O-2 supplied to the anode reacts on the anode catalyst and no O-2 was measured at the cell outlet for air bleed levels up to 2.5%.

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