Guwy, Alan

Laycock, Christian

Panagi, Kleitos

Reed, James

English

University of South Wales Research Explorer

Utilisation of renewable feedstocks in solid oxide fuel cell technology: biohydrogenChristian J. Laycock, Kleitos Panagi, James P. Reed, Alan J. GuwySustainable Environment Research Centre, University of South Wales, Pontypridd, CF37 4BD, UKIntroduction. Biologically produced mixtures of H2 and CO2 (biohydrogen) from processes such as dark fermentation or photo-fermentation are versatile feedstocks which can potentially be utilised in solid oxide fuel cell (SOFC) technology. SOFCs arehigh temperature (500 – 1000 °C) electrochemical energy conversion devices made with ceramic and metallic materials. Theyare highly efficient, operate silently and can be sized from 1 kWe to 1 MWe upwards due to their modular and scalable design.They can utilise hydrogen or carbon-based feedstocks either in fuel cell mode to produce electrical power and heat, orelectrolysis mode to produce useful chemicals such as synthesis gas (H2 + CO). This work investigates the performance andproducts of a solid oxide fuel cell operating on biohydrogen in both fuel cell mode and electrolysis mode.Results. On entry into the SOFC, approx. 30% of biohydrogen is converted into CO and H2O via the reverse water-gas shift(RWGS) reaction (see Figs. 1 and 2): H2 + CO2 ⇌ CO + H2Owww.flexis.wales  @FlexisProjectFLEXIS is part-funded by the European Regional Development Fund (ERDF), through the Welsh Government. Ariennir yn rhannol gan Gronfa Datblygu Rhanbarthol Ewrop drwy Lywodraeth Cymru.In fuel cell mode (see Fig. 1), the SOFC converts H2 intoelectrical power and heat. CO is converted via reaction withH2O and does not contribute to power production. When thecell is operated at high fuel utilisation efficiency (at 0.1 V inFig. 1), emissions of CO are minimal.In electrolysis mode (see Fig. 2), the SOFC converts CO2into CO, yielding synthesis gas. The H2/CO ratio can easilybe controlled in the range 1.2-2.3 by adjusting the operatingvoltage of the cell.Biohydrogen is inherently variable; however, Fig. 3 shows theelectrochemical performance of the cell is not significantlyaffected by fuel variability provided the H2 content ofbiohydrogen stays within the range 40-60 vol%.Conclusions. Biohydrogen is a useful and renewablefeedstock which can be utilised in SOFC technology to yielduseful energy and chemical products. Crucially, the resultsshow that CO2 scrubbing is not required for good SOFCperformance. Fuel conversion takes place via a complexinterplay that exists between the fuel cell reactions and theRWGS reaction.Figure 1. Utilisation of biohydrogen in SOFC in fuel cell mode. Theemissions and current output of the cell are shown.Figure 2. Utilisation of biohydrogen in SOFC in electrolysis mode.The syngas production rate and output gases are shown.Figure 3. The effect of fuel variability on the I-V and power curves ofan SOFC operating on biohydrogen. Data are shown for the celloperating on biohydrogen mixtures containing 10-90 vol% H2.Further reading. Laycock CJ, Panagi K, Reed JP, Guwy AJ, Theimportance of fuel variability on the performance of solid oxide cellsoperating on H2/CO2 mixtures from biohydrogen processes,Int J Hydrogen Energy 2018 34;8972-82.

Utilisation of renewable feedstocks in solid oxide fuel cell technology: biohydrogen

Utilisation of renewable feedstocks in solid oxide fuel cell technology: biohythane

https://pure.southwales.ac.uk/ws/files/3205224/FLEXIS_Young_Researchers_Conference_CJL.pdf

Utilisation of renewable feedstocks in solid oxide fuel cell technology: biohydrogen

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University of South Wales Research Explorer

University of South Wales Research Explorer