Replacing air with oxygen in coal-fired boilers (i.e. oxy-firing) combined with flue gas recirculation is a leading strategy to concentrate CO2 in the flue gas and assist in carbon capture for subsequent sequestration. A significant area of concern is the fireside corrosion with oxy-firing due to the higher CO2 levels in the combustion gas and potentially higher SOx and H2O levels. In order to investigate this complicated issue, laboratory experiments are being conducted with and without synthetic ash to assess the potential effect of oxy-firing on fireside corrosion rates. The initial results of this project focus on commercial and model Fe-base alloys at 600°C. Without ash, a 50%H2O-50%(CO2-0.15O2) environment was the most aggressive condition, requiring higher Cr contents than 100% H2O or Ar-50%CO2. With the specimens covered in ash, several gas compositions were examined including different levels of H2O and SO2 to simulate various oxy-firing strategies. Box plots were used to present the data for several laser cladding compositions for protecting tubes.

Subject
Composition, Nickel based alloys, Oxide formation, Metal oxides, Commercial alloys, Corrosion attacks, Mass gain, Oxide scales, Steel, Ash, Coal, Steam, Alloys
Keywords:
high temperature oxidation, coal ash corrosion, boiler, H2O, CO2
© 2012 Association for Materials Protection and Performance (AMPP). All rights reserved. No part of this publication may be reproduced, stored in a retrieval system, or transmitted, in any form or by any means (electronic, mechanical, photocopying, recording, or otherwise) without the prior written permission of AMPP. Positions and opinions advanced in this work are those of the author(s) and not necessarily those of AMPP. Responsibility for the content of the work lies solely with the author(s).
2012
Association for Materials Protection and Performance (AMPP)
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