Aboveground storage tanks require regular inspections of possible corrosion attacks on the tank bottom which typically calls for internal access leading to downtime and increased operational cost. A failure probability-based inspection approach utilizing non-intrusive technologies is the ultimate goal for operating above ground storage tanks in the most cost-beneficial way.

This article describes a novel approach that combines ElectroMagnetic Acoustic Transducer (EMAT) technology with Finite Element Method (FEM) modeling for the detection and prediction of corrosion growth and the remaining structural strength of the tank while remaining in service.

The tank bottom is scanned from the outside by EMAT technology. The resulting B-scan with identification of the corrosion attack locations is post-processed and mapped on a virtual twin model of the tank. The corrosion conditions at the bottom tank plate are determined based on polarization measurements in a drain water sample taken from the tank and inserted into the model. A 3D FEM model with intelligent high-resolution meshing around the defect areas allows calculating the current distribution and thus estimating the corrosion rate at the defect locations. This model with high-resolution meshing is then also further used for calculating the mechanical stress on the tank bottom while accounting for the wall thickness loss at the defect locations.

Periodic inspections, combined with virtual twin model simulations, allow for monitoring the structural health of assets and optimizing a failure probability-based inspection strategy.

Subject
Water, Modeling, Corrosion rate, Waves, Inspection, Corrosion detection, Stress, Meshes, Defects, Corrosion modeling, Tank bottoms, Elements, Oil
Keywords:
Corrosion management, Failure Probability Based Inspection, Non-Intrusive, Simulation, and Modeling, Corrosion monitoring
© 2023 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).
2023
Association for Materials Protection and Performance (AMPP)
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