12. Vapor Phase Silica Transport During SOFC Operation at 1000°C

  1. Narottam P. Bansal
  1. Prabhakar Singh and
  2. Shailesh D. Vora

Published Online: 26 MAR 2008

DOI: 10.1002/9780470291245.ch12

Advances in Solid Oxide Fuel Cells: Ceramic Engineering and Science Proceedings, Volume 26, Number 4

Advances in Solid Oxide Fuel Cells: Ceramic Engineering and Science Proceedings, Volume 26, Number 4

How to Cite

Singh, P. and Vora, S. D. (2005) Vapor Phase Silica Transport During SOFC Operation at 1000°C, in Advances in Solid Oxide Fuel Cells: Ceramic Engineering and Science Proceedings, Volume 26, Number 4 (ed N. P. Bansal), John Wiley & Sons, Inc., Hoboken, NJ, USA. doi: 10.1002/9780470291245.ch12

Author Information

  1. Pacific Northwest National Laboratory Richland, WA 99352

Publication History

  1. Published Online: 26 MAR 2008
  2. Published Print: 1 JAN 2005

ISBN Information

Print ISBN: 9781574982343

Online ISBN: 9780470291245

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Keywords:

  • silica deposition;
  • silica deposition;
  • methane concentration;
  • microstructural;
  • gulbransen

Summary

During the operation of tubular solid oxide fuel cells (SOFC) at 1000°C in CH4-H2O fuel, we observed silica deposit formation on the fuel electrode (Ni-YSZ cermet), nickel felt contacts and reforming catalyst surfaces. Silica deposition on the fuel electrode resulted in the electrical performance degradation, coverage of the catalyst surface and breakdown of the zirconia skeleton present on the fuel electrode. Sources of silica were identified. A thermohemical model relating to the formation and transport of vapor phase silica species, deposition on the catalytically active surface and interaction with the anode was developed. Vapor transport of silica is considered to take place at the quartz surface in the presence of water vapor. Silica deposition and deactivation of the catalyst is postulated to be due to the dissociation of gaseous hydrated silicious species on the active nickel surface during the reformation of hydrocarbon. Experiments were designed and conducted to validate the mechanism. It is concluded from these experiments that the presence of silica in the solid oxide fuel cell generator and the catalyst support should be eliminated for long term stable operation of cells and generator.