Post on 16-Oct-2021
Quantitative Acoustic Emission (QAE)
Tom Watkins, CM
Manager, Client Support
Margan
April 16-17, 2013
Objectives
• Why inspect High Energy Pipe (HEP)?
• What is QAE Technology?
– A Non-Destructive Inspection (NDI) screening & monitoring tool
• How does QAE work?
– The phenomenon of acoustic emission
Objectives
• What is the QAE process?
– Equipment / Installation / Testing / Analysis
• Applicability
– P22 and P91
• Case studies
– Effectiveness, advantages, and cost savings
• Summary
Protect Physical
Assets and Employees
Aging Plants
Operation
P21 / P91
Uncertainty
Reduced Safety Factors
Comprehensive
Inspection
Program
Why Inspect HEP?
What Is QAE
• A passive system
– Converts released flaw development energy into acoustic signature
– Does not induce seismic or sonic energy into the HEP
• On-line system
– Sensing devices are installed while on-line
– Data is collected while on line
What Is QAE
• A Predictive Maintenance (PdM) tool for your Reliability Centered Maintenance (RCM) tool kit
– Flexible coverage • 100% or can be limited to high risk zones
• Can move traditional NDE from time based to conditioned based inspections
What Is QAE
• A monitoring process
– Continuous real time or period based
– Entails trending data
– Provides early alert to developing issues
What Is QAE
• A strategic – screening tool
– Optimizes knowledge of HEP integrity over time • Provides visual map
– Assists in prioritizing NDE inspection efforts • UT, MT, LPA, replication
– Reduces uncertainty • Provides sense of urgency
– Facilitates outage planning
What Is QAE
• A strategic – screening tool
– Helps improves budget process
– Enables cost reductions
– Helps defer or avoid unnecessary NDE
– Reduces need for • Scaffolding
• Insulation removal
QAE Limitations
• Indication must be active – Emit or resonate when placed under stress
• Does not “precisely” locate indication along linear length – +/- 10% (or approximately 1 foot)
• Does not differentiate between surface and subsurface location
• Does not provide size of indication
QAE Limitations
• Sensitive to background noise fluctuation and magnitude
• Can be overly sensitive – Small but very active indications
• Multiple flaws near same location cannot be differentiated
Tree Falls
Paper Tear
How Does QAE Work?
Fracture or deformation processes in differing materials have different signatures.
Fracture or deformation processes in differing materials have different signatures.
ICE CRACK Glass Ice Crack Break Glass
How Does QAE Work?
QAE System Collects and Converts
Acoustic Emission is a phenomenon of sound and ultrasound wave radiation in materials that undergo deformation and fracture processes.
How Does QAE Work?
Burst AE is a qualitative description of the discrete signal's related to individual emission events occurring within the material Continuous AE is a qualitative description of the sustained signal produced by time-overlapping signals
How Does QAE Work?
J1 Critical
Flaw accumulation and development
•Micro / macro-cracking
•Fracturing and de-bonding of hard inclusions
•Creep development.
Mechanical impacts and friction
•Hanger impacts and knocks
•Friction at side supports
•Dynamic overstressing
•Shock waves due to steam pulsation
Leaks, malfunctioning valves, and steam fluctuations
•Leaks
•Malfunctioning valves
•Steam fluctuations due to control problems
What Can QAE Detect?
Type I – Flaw Suspected activity
Type II – Impact and friction
Examples of AE Sources
Margan confidential and proprietary information
Examples of AE Sources
Valve Leaks Malfunctioning Valves
Leaks
Leak
Margan confidential and proprietary information
What Is Margan’s QAE Process?
Equipment System Design & Installation
Data Acquisition
Data Analysis Report
Margan confidential and proprietary information
Equipment
• P22 Waveguide
– Provides signal pass & dissipates heat before sensor
– ¼” Stainless steel with an aluminum flux ball
– Ceramic sensor converts pulse to electrical signal
EPRI Margan
Margan confidential and proprietary information
Margan
Equipment
• P91 Waveguide
– P91 material welding attachment standards require • Capacitor welding method
– A specific waveguide
Margan confidential and proprietary information
Equipment
• Other – Cable – Preamplifier – BNC Cable Connectors – Resonance Sensor – Integrated Pre-amplifier – AE PCI 4 Cards – Software
Cable
Cable Trays
BNC Connector
Sensor +
Preamplifier
Margan confidential and proprietary information
Design
• Sensors strategically spaced
– Sensor spacing is function of sensor sensitivity, background noise, piping accessories, attentuation, etc.
• EPRI guidelines – 15 to 18 feet in low background noise
– 10 to 13 feet in high background noise
• Margan procedure – 12 feet maximum
– Increased sensitivity and reliability
– <3 feet from piping accessories
– Wye blocks, attempterators, hangers, etc.
– Install on same circumferential side of pipe
Margan confidential and proprietary information
Installation
Minimal Insulation Removal
Terminal Point Welding Waveguide No Scaffolds - Rope Access
Margan confidential and proprietary information
Data Acquisition
• Margan uses 3 calibration protocols
1) Sensor response to a preset noise level
2) Acoustic emission energy distribution
3) Sensor attentuation v distance to sensor
• Calibration is critical stage for accuracy
Margan confidential and proprietary information
400
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0 50 100 150 200 250 300 350 400 450 500 550 600 650 700 750 800 850 900 950 1000
Background noise energy
Ene
rgy
with
the
nois
e g
ener
ator
5DV1CR13 Vermilion U1 CRH p1-25 March 08 noise Energy
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Point
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age
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gy
Source #P 12
P 18
P 17
P 16
P 15
P 14
P 13P 11
P 10P 9
P 8P 7
P 6
0
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-20 -15 -10 -5 0 5 10 15 20
Position[m]
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gy [a
.u.]
a
b
Data Acquisition
Margan confidential and proprietary information
Margan Procedures EPRI Guidelines
Most of the inspection is performed under
stable load conditions of plant operation.
During baseline, it is recommended to perform
low and variable load measurements (see
below)
Stress method should not excessively stress the
piping. Piping should be monitored under
normal stable conditions.
Variable load measurement- the load swings
between 90% to 100% of full load back and
forth. This is done to monitor dormant flaws,
which emit under changes in stress.
The load swing should include a pressure
change of at least 25% of the piping operating
pressure range.
Low load measurement- the load is lowered to
70% of full load. This is done especially to
monitor piping with high noise background,
which will assist in filtering it.
Data Analysis
Margan confidential and proprietary information
OP Conditions
Continuous Burst
Linear
Location
2D-3D
Location Data Normalizing
Signals Location
Noise Separation
Signals
Classification
History
Severity
Classification
AE Data
Data Analysis
Margan confidential and proprietary information
3σ
a
b
Margan confidential and proprietary information
Data Analysis
Applicability To P22
• Bench test P22 correlation strain v AE v time
– Transition point occurs at ½ life
– Transition correlates to 1st QAE increase
– Strong correlation
Margan confidential and proprietary information
Applicability To P22
Margan confidential and proprietary information
Applicability
• For both P91 and P22 – QAE can detect and accumulate energy trend
• Anticipate failure and location of failure
• Highlights use as a PdM tool to reduce risk
• P91 reacts differently to strain than P22 – More sudden failure
• Supports even a greater need for use on P91
Margan confidential and proprietary information
Creep Processes
emit Energy
Deformation
Stress Waves
Elongation
(Strain)
AE Signal
(Energy)
Correlation
Applicability
Detectable by
QAE NDI and UT
Detection by
QAE NDI 2 1
3
4
Detection by
QAE NDI
AE Is Emitted As Creep Accumulates
Creep Damage Accumulation Diagram
* Under normal
background noise
conditions
Case Studies
• Case study 1 MS line
– System installed on MS line IN 2004
– No special events reported until 2009 • Inspection reported abnormal activity in section leading to
turbine leads
– During 2011 outage, client performed NDE • Cracks and creep were found
Margan confidential and proprietary information
Case Studies
Margan confidential and proprietary information
2006
2007
2009
Case study 1 MS line
Case Studies
Case study 1 MS line
Margan confidential and proprietary information
February 2006 and 2007
January 2009
Case Studies
Margan confidential and proprietary information
Case study 1 MS line
Creep 5 Creep 3 Creep 2
UT, MT and replica in 2011
Case Studies
Margan confidential and proprietary information
Feb 2003 Oct 2003 July 2006 2 days
later
Baseline QAE MC
1st TMI QAE Increased
Activity
TMI- Trend monitoring Inspection
MC- Micro-Cracking
MT- Magnetic Particles Inspection
LPA- Linear Phased Array
NRI- No Reportable Indications
MT LPA NRI
Feb 2005
2nd TMI QAE Increased
Activity
Leak In weld
14
2x40’’ Thermal
Fatigue cracks
Fatigue Crack
Crack identified by LPA in 2006
Case study 2 CRH line: thermal shock / fatigue
Case Studies
Margan confidential and proprietary information
Case study 2 CRH line: thermal shock / fatigue
DHAVAN33 Dynegy. Havana. Unit6. CR points 1-20 Eng3SN + 10,Avg48
0
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1 2 3 4 5 6 7 8 9 10 11 12 13 14 15 16 17 18 19 20
Point
Hits
Feb. 2003 CS Feb. 2005 CS March. 08 CS
Feb 2003
Feb 2005
Feb 2008 After line repair
Fatigue Crack
Intensive AE activity in 2003 and 2005. The activity decreased after elbow replacement and repairs (2008)
Crack identified by LPA in 2006
AE
Act
ivit
y
14 15
Case Studies
Margan confidential and proprietary information
2004 - Two areas were recommended by QAE NDI to be inspected by localized NDE methods due to indications of micro-cracking and creep development.
2005 - Top area: creep class 3 was revealed by replica several indications were revealed by UT. Surface cracks were revealed by MT and grind out.
Bottom area: creep class 4 was verified by replica investigation.
Linear Phased Array Ultrasonic Examination revealed accumulation of multiple processing indications.
Case study 3A HRH line
Case Studies
Margan confidential and proprietary information
Company 2 Company 1
Class 1 creep 7/12, Class 2 creep 5/12 Class 3 creep 2/2* Zone 1
Class 1 creep 3/12, Class 2 creep 9/12 Class 4 creep 2/2 Zone 2
Re-inspect in 8-10 years. Repair in six months to one year time period.
Recommend
Replica investigation at girth welds located at zones between AE
points 44-45-50 and 51-52.
Zone 1
Zone 2
Case studies 3A and 3B HRH line
Case studies 3A and 3B HRH line
Case Studies
Margan confidential and proprietary information
Company 2; creep class 2 Company 1; creep class 4
Case Studies
• Case study 4 hanger assessment
– In 2000 Unusual AE Activity Noted
– Activity Increased 6-Months Later
– Visual Inspection • Rigid Hangers
• Hanger Repaired
Margan confidential and proprietary information
Margan Provides Hanger Assessment With Each Report
Margan confidential and proprietary information
Case Studies
• Case study 5 thermal shock
– Thermal shock zone is increasing
– With time and as more
– Attemperation is applied
Start of intensive AE activity when attemperator opening is above 40%.
January 2009
Attemperator valve opening [%]
Piping area subjected to thermal shock/overstresses between
0-30% AE points 8-14
30-40 AE points 6-16
>40 AE points 1-19
Case Studies
• Case study 5 thermal shock
– Thermal shock zone is increasing
– With time and as more
– Attemperation is applied
Margan confidential and proprietary information
Start of intensive AE activity when attemperator opening is above 20%.
January 2010
Attemperator valve opening [%]
Piping area subjected to thermal shock/overstresses between
0-20 AE points 8-13
>20 AE points 1-19
Case Studies
• Case study 6 new install economics
– Probability of failure <1%, but consequences very high
– After 10 years only about 21% of the HEP inspected • QAE would provide 100% coverage more frequently
– Cost from traditional NDE on 100% of MS, CHR, and hrhline equaled ~$1.9 million / unit (excluding any asbestos)
Margan confidential and proprietary information
Insulation
Remove &
Reinstall
Scaffolding Local NDE $1.9M
Case Studies
• Case study 6 new install economics
– Unit had to be off line to complete traditional NDE
• Replacement power could add to $1.9 million cost
– QAE capital had <3 year payback • Would provide 100% coverage every 2 to 3 years
• Would help prioritize NDE on higher risk areas
• Required less scaffolding and insulation removal
Margan confidential and proprietary information
Summary
• QAE NDI is:
– A PdM monitoring and trending program and
– A RCM diagnostic and screening tool
• QAE is a part of a comprehensive HEP inspection program
• QAE can differentiate between various acoustic signatures
Summary
• QAE works on both P22 and P91
• QAE reduces overall risk
• QAE helps to target and prioritize higher risk areas
• QAE supplements traditional NDE
• QAE is cost effective – QAE facilitates outage planning and budget process
Objective
When To Use QAE?
How And Where Does QAE Work?
Why Use QAE As Part Of A Comprehensive Inspection
Program?
What Is QAE?
Margan confidential and proprietary information