Determination of acceptable contaminant levels for PEM fuel cell stacks and poisoning mitigation strategies
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Typ
Examensarbete för masterexamen
Master Thesis
Master Thesis
Program
Applied physics (MPAPP), MSc
Publicerad
2014
Författare
engström, agnes
Modellbyggare
Tidskriftstitel
ISSN
Volymtitel
Utgivare
Sammanfattning
PEM fuel cells are a promising alternative to today’s internal combustion engines. One problem with PEM fuel cells is performance degradation due to contaminations in the fuel. In this thesis, the acceptable contaminant levels for PEM fuel cell stacks were determined for some contaminants. The contaminants used in this thesis were NH3, CO, C2H4, C2H6, C3H6, H2S and SO2. The measurement methods used were electrochemical in situ methods. For all contaminants, the voltage was measured during contamination with different concentration levels, while the current density was held constant at 0.5 A/cm2. For NH3, the electrochemically active surface area and membrane resistance were measured as well. The contaminants that poisoned the fuel cells were NH3, CO, H2S and SO2. For these four contaminants, the poisoning of the fuel cells was irreversible if the concentration was high enough and the exposure time long enough. The short chain hydrocarbons C2H4 and C2H6 did not show any poisoning mechanism on the fuel cells. The measurements made with C3H6 were not sufficient to draw any conclusions from. One poisoning mitigation strategy used to mitigate the poisoning effect of CO was the addition of small amounts of air to the fuel. The addition of 0.5 % air to the fuel increased the acceptable CO level from 10 to 25 ppm.
Beskrivning
Ämne/nyckelord
Energi , Grundläggande vetenskaper , Hållbar utveckling , Innovation och entreprenörskap (nyttiggörande) , Annan teknik , Energy , Basic Sciences , Sustainable Development , Innovation & Entrepreneurship , Other Engineering and Technologies