Advanced Acoustic Emissionfor On-stream Inspection of Petroleum

Industry Vessels

Current Approach - MONPAC PLUSCurrent Approach - MONPAC PLUS

Evaluation of Pressure Vessels - MonPac Plus AE Technology Program Developed by MONsanto and

Physical Acoustics Corp. Applications

Structural Integrity Monitoring Leak Detection Process Monitoring Materials Research

Sponsored by ten companies, including seven financially (Exxon/Mobil, Shell, Saudi Aramco, BP, Chevron and Petrobras) and three vendors (PAC, QSL -Plus and Matrix) for equivalent in-kind contributions

Collaborating with NASA LRC

University Support: Dr. R. Weaver - Univ Illinois (UI), Dr.

Chon Tsai, Dr. Stan Rokhlin - Ohio State Univ (OSU), Dr.

W. Sachse - Cornell, Dr. Mandayam - Rowan

PERF 95-11: Advanced AE for On-Stream InspectionPERF 95-11: Advanced AE for On-Stream Inspection

Accurate Source Location Quantitative AE/FFS Relationship Reliable Source Discrimination PERF-PAC AE Software & System Recommended Practice & Guidelines

Advanced AE for On-stream InspectionAdvanced AE for On-stream Inspection

The overall objective of this effort is to deliver reliable AEmethods for global, on-stream inspection of pressure vesselsin lieu of internal inspection incorporating advances in;

Pre-Test Support (built into the software) for assisting in

setting up an AE Examination based on vessel

parameters, attenuation analysis, and user desired

minimum detectable crack size.

Real Time Acquisition of waveforms with improved event

detection, event timing features, accurate source location,

source discrimination, crack size quantification, and

Fitness for Service Analysis determination without need

for follow-up NDT inspections after the test.

Advanced AE for On-stream InspectionAdvanced AE for On-stream Inspection

The result of this work is to be a waveform based, procedure driven, Multi-channel AE System and Software for planning and conducting advanced AE vessel testing composed of;

Pre-Test AnalysisPre-Test AnalysisAdvanced Dispersion Curve analysis Main setup menuAdvanced Dispersion Curve analysis Main setup menu

Example Source: surface Material: 2”-thick carbon steel

plate Fluid Loading: Water on one

side (hydrotest) Source-to-sensor Dist: 0.5m Sensor: PAC R-15I sensor Filter: 3 - 300kHz Bandpass,

or 100-300 kHz Bandpass

Pre-Test Analysis SupportPre-Test Analysis SupportWaveform Prediction from Material Properties and Dispersion Waveform Prediction from Material Properties and Dispersion

CurvesCurves

Predicted waveform at sensor face Predicted waveform out of sensor

Pre-Test Setup & Analysis SupportPre-Test Setup & Analysis SupportAttenuation SetupAttenuation Setup

Attenuation Setup Menu Attenuation Map on Vessel

Pre-Test Setup & Analysis SupportPre-Test Setup & Analysis SupportAttenuation AnalysisAttenuation Analysis

Triangular Attenuation

Map

Zonal Attenuation Map w/0dB weld atten.

Zonal Attenuation Map w/4dB weld atten.

Pre-Test Setup & Analysis SupportPre-Test Setup & Analysis SupportMinimum Crack Size DeterminationMinimum Crack Size Determination

.

Vessel is shown overlaid on location plot with welds and nozzles showing.

Graphs show a series of pencil lead breaks along the length of the vessel.

Top graph shows the point plots colored based on the received amplitude at the first hit sensor.

Bottom graph shows the Point Plots colored based on the “Source Amplitude” corrected values, using the Attenuation graph setup during pre-test. FFS assessment relies on the Source Amplitude feature.

PERF-PAC Acquisition and AnalysisPERF-PAC Acquisition and AnalysisLocation GraphingLocation Graphing

Location Graph with Amplitude based points

Location Graph with “Source Amplitude” based points

PERF-PAC Acquisition and AnalysisPERF-PAC Acquisition and AnalysisDetailed Event AnalysisDetailed Event Analysis

Any event can be accessed by Hit/Event Linking to show the waveform composition and the event and hit data which forms the event.

Just move the data cursor over a point, right click and select Hit/Event Linking to show the waveform and event data.

PERF-PAC Acquisition and AnalysisPERF-PAC Acquisition and AnalysisDetailed Event AnalysisDetailed Event Analysis

Any event can be accessed for Fitness for Service Assessment via a FAD Diagram (Failure Assessment Diagram) in acquisition or replay

Just move the data cursor over a point, right click and select FAD Analysis to show the FAD Diagram.

PERF-PAC Acquisition and AnalysisPERF-PAC Acquisition and AnalysisSphere Location and Event AnalysisSphere Location and Event Analysis

Traditional longitude/latitude lines to help show position or actual weld lines per ASME can easily be setup in spherical location mode. Note sensor #2 is reference 0,0 position. Note also transparency of location dots on reverse side of sphere. Sphere can be rotated freely in acquisition or replay.

Continuing Experiments to determine AE to Crack Relationship. (Work is currently being conducted at Rowan University on a bi-axial loading machine).

Reliable Source Discrimination work is continuing at Cornell University with assistance from Univ Illinois.

Testing of Pressure Vessels starting in September 2004. Completion of Recommended Practice & Guidelines (for

PERF-PAC testing)

Continuing PERF 95-11 EffortsContinuing PERF 95-11 Efforts

Reliable Source DiscriminationReliable Source Discrimination

Identify source based on signal response Discrimination methods evaluated

Time-frequency Analysis Neural Network Wavelet Pattern Recognition

Time-Frequency Analysis and Pattern Recognition are being further investigated.

Reliable Source DiscriminationReliable Source DiscriminationStudying the Inverse ProblemStudying the Inverse Problem

Original Spectrogram of AE waveform Processed Spectrogram with actual colored wave modes overlaid.

By performing “Frequency - Time” Analysis on the received AE waveform, it is possible to extract the original wave modes as material properties are already known. Then with the determination of source distance, one can determine the original moment tensors, leading to a description of the source. Crack sources can then be distinguished from other sources. However, the above example is based on theoretical wideband waveforms.

Field ExperienceField Experience

Items Tested – 8 Total Tests Cooling Tower Reactor Vessels Horizontal Pressure Vessel Piping

ObservationsObservations

Developments have enhanced ability to perform a more effective AE test

Accurate Source Location improved significantly FFS analysis very conservative