Mechanical and corrosion properties and overall cost of weldable 13% Cr stainless steel make the material an attractive alternative for subsea production flowlines. However, the material may be susceptible to hydrogen cracking in combination with cathodic protection. This paper describes the design and qualification of a diode controlled cathodic protection system for the Fram Vest 13% Cr production flowline. The flowline was installed in the North Sea in the summer of 2003 and has a protection system consisting of polypropylene thermal insulation and sacrificial anodes connected to the pipeline via diodes and stainless steel cathode plates. The design potential of the pipeline is in the range -600 to -750 mV vs. Ag/AgCl/sea water reference electrode.

Subject
Cathodes, Materials, Piping, Anode potential, Cathodic protection, Pipelines, Free corrosion potential, Flowlines, Current densities, Coating breakdown, Protection potential, Hydrogen, Anodes
Keywords:
cathodic protection, CP, 13% Cr, flowline
© 2004 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).
2004
Association for Materials Protection and Performance (AMPP)
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