Condensing flue gases are highly corrosive and present severe challenges in terms of materials selection. The sulphuric acid condensation which occurs in coal-fired power plants has been long recognised as a cause of corrosion in flue gas desulphurisation (FGD) units, but the more complex conditions which can arise with increasing combustion or co-combustion of biomass and waste have been less thoroughly investigated. In this paper results are presented from laboratory tests designed to simulate the corrosive conditions in flue gas cleaning systems and based on analysis of actual condensate. The major focus is on waste combustion, where the main condensate component is hydrochloric acid but varying amounts of H2SO4, HBr, HNO3, HF and metal ions may also be present.

These data are correlated to field tests of creviced and welded coupons in power plants. The range of steels investigated spans from UNS S31726 to the superaustenitic grades S34565, S31254 and S32654 and the superduplex S32750. Results are presented in terms of the measured uniform corrosion rates, and the contributions from crevice corrosion are considered. Comparisons are made to earlier data from coal fired plants.

Subject
Materials, Corrosion rate, Nickel based alloys, Condensation, Condensates, Flue gas, Crevices, Crevice corrosion, Power plants, Pitting, Wastes, Corrosion potential, Cleaning
Keywords:
Stainless, testing, corrosion, flue gas cleaning
© 2013 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).
2013
Association for Materials Protection and Performance (AMPP)
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