The paper relates the 20 year history (1970 - 1990) from the early discovery of stress corrosion cracking in the Vetrocoke CO2 removal units of 3 ammonia plants. The units use recirculating solutions of potassium carbonate/bicarbonate containing arsenic inhibitor in large carbon steel absorber and stripper vessels. The advent of scc brought about the need to develop a policy for safe operation of the units. This was achieved initially through a combination of potential monitoring and an inspection and repair policy based upon a fracture mechanics evaluation of the vessels, subsequently supplemented by acoustic emission testing and the attempted development of a on-line scc monitoring system using electrochemical noise. The various approaches to the problem are described in the paper, and some general lessons are drawn.

Subject
Materials, Electrochemical noise, Potential range, Inspection, Free corrosion potential, Stress cracking, Solutions, Defects, Crack velocity, Towers, Electrodes, Stress corrosion cracking, Electrode potential
© 1991 Imperial Chemical Industries PLC. 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 prior written permission. 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).
1991
Imperial Chemical Industries PLC
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