Metallic materials selected for the construction of in-bed heat exchangers and tube support structures in fluidized-bed combustion (FBC) systems must withstand the corrosive conditions prevalent in these systems. Oxidation/sulfidation interactions leading to accelerated metal wastage of in-bed materials can occur owing to the presence of sorbent deposits on the metal surfaces and/or the low oxygen partial pressures in the exposure environment. The present paper discusses the possible mechanisms of sulfidation of iron-base ferritic and austenitic alloys and the roles of key parameters such as sorbent chemistry, gas chemistry, metal temperature, and gas cycling conditions in the corrosion process. Data on the scale thickness and depth of intergranular penetration are presented for carbon steel, Fe-2 1/4Cr-1Mo and Fe-9Cr-1Mo ferritic steels, Types 304 and 310 stainless steel and Incoloy 800 as a function of the chemistry of the exposure environment, deposit chemistry, and exposure time. The 2000-h test results from the laboratory materials evaluation program and the available data on characterization of in-bed environments are used to assess the corrosion behavior of in-bed materials in FBC systems.

Subject
Sulfur, Materials, Stainless alloys, Substrates, Partial pressures, Penetration, Metals, Scale thickness, Sulfidation, Oxygen, Deposit corrosion, Alloys, Chemical reactions
© 1986 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).
1986
Association for Materials Protection and Performance (AMPP)
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