Campus Units

Center for Nondestructive Evaluation, Aerospace Engineering

Document Type

Article

Publication Version

Published Version

Publication Date

5-2015

Journal or Book Title

SPIE Proceedings

Volume

9439

First Page

94390M

DOI

10.1117/12.2084223

Conference Title

Smart Materials and Nondestructive Evaluation for Energy Systems 2015

Conference Date

March 9–10, 2015

City

San Diego, CA, United States

Abstract

Oil refinery production of fuels is becoming more challenging as a result of the changing world supply of crude oil towards properties of higher density, higher sulfur concentration, and higher acidity. One such production challenge is an increased risk of naphthenic acid corrosion that can result in various surface degradation profiles of uniform corrosion, non-uniform corrosion, and localized pitting in piping systems at temperatures between 150°C and 400°C. The irregular internal surface topology and high external surface temperature leads to a challenging in-service monitoring application for accurate pipe wall thickness measurements. Improved measurement technology is needed to continuously profile the local minimum thickness points of a non-uniformly corroding surface. The measurement accuracy and precision must be sufficient to provide a better understanding of the integrity risk associated with refining crude oils of higher acid concentration. This paper discusses potential technologies for measuring localized internal corrosion in high temperature steel piping and describes the approach under investigation to apply flexible ultrasonic thin-film piezoelectric transducer arrays fabricated by the sol-gel manufacturing process. Next, the elastic wave beam profile of a sol-gel transducer is characterized via photoelastic visualization. Finally, the variables that impact measurement accuracy and precision are discussed and a maximum likelihood statistical method is presented and demonstrated to quantify the measurement accuracy and precision of various time-of-flight thickness calculation methods in an ideal environment. The statistical method results in confidence values analogous to the a90 and a90/95terminology used in Probability-of-Detection (POD) assessments.

Comments

This paper is from Proc. SPIE 9439, Smart Materials and Nondestructive Evaluation for Energy Systems 2015, 94390M (March 27, 2015); doi:10.1117/12.2084223. Posted with permission.

Rights

Copyright 2015 Society of Photo Optical Instrumentation Engineers. One print or electronic copy may be made for personal use only. Systematic reproduction and distribution, duplication of any material in this paper for a fee or for commercial purposes, or modification of the content of the paper are prohibited.

Copyright Owner

Society of Photo Optical Instrumentation Engineers

Language

en

File Format

application/pdf

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