Flexible pipes are made of steel wires covered with a minimum of two polymer sheaths from inside (to protect the line from the bore flow) and outside (to protect the line from sea water). The space between the inner and outer polymer sheaths form an annular where corrosive species such as H2S, CO2, and H2O can penetrate, condense and accumulate. Corrosion in such conditions features some unique characteristics that are very different from conventional production lines. The amount of the electrolyte is very limited in these applications. This causes the electrolyte to become saturated with the corrosion products and disturbs the chemical reactions that ultimately cause corrosion. Broadsword Corrosion Engineering decided to develop a comprehensive and up-to-date model suitable for these applications. The model incorporates the effect of transport processes, the chemical reactions occurring in the electrolyte, and the electrochemical and precipitation reactions that occur at the surface of the metal. The model was validated using the client’s third-party laboratory testing and other experimental data. Several simulations were performed and the effects of pressure, temperature, and volume-to-surface-area were investigated and discussed in details.

Subject
Piping, Precipitation (solids), Corrosion rate, Predicted corrosion rate, Metal surfaces, Diffusion, Electrochemical reactions, Partial pressures, Anodic reactions, Corrosion modeling, Metals, Chemical reactions, Electrolytes
Keywords:
Simulation, Sweet and Sour Corrosion, Flexible Pipes
© 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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