When properly applied, liquid-applied organic coating materials offer an important tool in the arsenal of available technologies for stabilizing and even rehabilitating Power Plant Service Water Systems (SWS’s) that have experienced the deteriorating effects of corrosion, erosion, and fouling. Traditionally, use of coating-type linings has been limited, largely because conventional materials had not proven sufficiently reliable in comparable service, such as circulating water systems. Some SWS linings may be considered safety-related by the definition that debris, which could occur should the lining fail, could foul components such as strainers and heat exchangers in RHR and similar safeguard systems. This paper focuses on a relatively new breed of one hundred percent solids (non-solvent emitting) coating materials which, when combined with customized application processes and close control of quality, have proven quite serviceable in water flow systems. Design considerations and crucial process details are reviewed.

The configuration and as-built physical environment of many parts of the SWS presents severe constraints on the accessibility of the constituent pipe and components. Where in-service inspection (ISI) indicates that existing linings have deteriorated, innovative techniques are required if a new lining is to be installed or repairs are to be effected. Established techniques and equipment available in the oil and gas and municipal water and sewage industries, creatively coupled with emerging equipment system developments, provide viable capabilities for in-situ lining application and repair. Examples of the more promising materials and systems are highlighted.

A summary of unique solutions for typical SWS performance problems which are available through specialty coatingtype lining materials and applications is discussed. These include:

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    Selective application of epoxy to check dealloying

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    Using Heat Exchanger (HX) tube ID coating to eliminate inlet end erosion and down tube corrosion

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    The emerging capabilities of non-toxic biofoul resistant coatings, when configured compositely with epoxy linings, for pipe, channels and tube ID’s

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    The role of coating-type linings in precluding MIC-related deterioration

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    Restoring HX tube-to-tubesheet joint strength and leak tightness without rerolling and/or metal inserts

The key elements for achieving serviceable results for these applications are outlined.

Subject
Coating application, Water, Coatings, Materials, Piping, Tubes, Abrasives, Solvents, Epoxy coatings, Heat exchangers, Metals, Linings, Epoxies
Keywords:
power plant, service water, heat exchangers | tubesheets | tube internals | pipe systems, epoxy, linings | rebuilding | restoration, pigging, antifouling
© 1990 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).
1990
Association for Materials Protection and Performance (AMPP)
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