Journal Article

PreJuSER-10079

http://join2-wiki.gsi.de/foswiki/pub/Main/Artwork/join2_logo100x88.png Long-term flue gas exposure effects of silica membranes on porous steel substrate

Brands, K.FZJ* ; Uhlmann, D.FZJ* ; Smart, S.FZJ* ; Bram, M.FZJ* ; Diniz da Costa, J. C.FZJ*

2010
Elsevier New York, NY [u.a.]

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Please use a persistent id in citations: doi:10.1016/j.memsci.2010.02.065

Abstract: In this work we investigate the long-term effects of exposing an inorganic membrane for 1100 h in a flue gas stream of a coal power plant. Of particular importance, from an industrial testing perspective, was the effect of fly ash deposition, water vapour and acid gases on the integrity of the membrane made of cobalt silica coated on a substrate of 316L steel, with interlayers of 310S steel, yttria-stabilized zirconia and gamma-alumina. Subsequent to the flue gas testing, the membrane was characterized for single gas permeance, SEM and EDX spectroscopy. Diffusion of nickel and chromium during sintering was observed at the interface of the 316L/310S steels, resulting in a reduced capacity to withstand corrosion in this area. Single gas permeation testing following flue gas exposure revealed a maximum permeation of 1.85 x 10(-8) mol m(-2) s(-1) Pa-1 and 2.13 x 10(-8) mol m(-2) s(-1) Pa-1 for helium and hydrogen respectively, and selectivity of 5.1 and 5.2 for He/N-2 and H-2/CO2 respectively, was achieved at a pressure difference of 2 x 10(5) Pa (2 bar) at 200 degrees C. The permeation behavior of the membrane appeared to be altered as a result of flue gas exposure with the membrane displaying a reduced H2 flux in contrast to an unexposed but otherwise identical membrane which displayed fluxes an order of magnitude higher than the membrane used in the power plant. This change in permeation behavior was thought to be the result of densification of the silica matrix following long-term exposure to flue gas containing water vapour. Micro-fractures in the surface of the cobalt silica gas separation layer were also observed, possibly the result of expansion due to corrosion. However, bulk diffusion was not observed suggesting that the layer was not completely compromised. (C) 2010 Elsevier B.V. All rights reserved.

Keyword(s): J ; Flue gas (auto) ; Stainless steel (auto) ; Yttria-stabilized zirconia (auto) ; Silica (auto) ; Gas separation (auto)

Note: The project "Nano-structured ceramic and metal supported membranes for gas separation-METPORE" is funded by the Bundeswirtschaftsministerium fur Wirtschaft und Technologie (BMWi), Forderkennzeichen 0327746A. Funding is gratefully acknowledged. The authors also acknowledge financial support through the Innovation Funds given by the Queensland Government (Australia), with further support in Australia from Tarong Power, Stanwell Corporation and the Australian Coal Association via the Centre for Low Emissions Technology (www.clet.net), and in Germany by EnBW, E.ON and RWE. The authors would like to thank D. Sebold for her help in characterizing the membranes, F. Hauler, G. Gottlicher (EnBW) and C. Blessing (EnBW) for experimental support.

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Contributing Institute(s):

1. Werkstoffsynthese und Herstellungsverfahren (IEF-1)

Research Program(s):

1. Rationelle Energieumwandlung (P12)

Appears in the scientific report 2010

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