Copyright © 2010 Proprietary Information: no dissemination, use or duplication allowed “Maximizing cylinder life cycle” Avoiding hydrostatic testing and

Copyright © 2010 Proprietary Information: no dissemination, use or duplication allowed

“Maximizing cylinder life cycle”

Avoiding hydrostatic testing and operating shutdowns using Acoustic Emission Testing.

Applications on spheres and underground tanks

Mehdi BATEL, Jean-Claude LENAIN (MISTRAS Group S.A), José LOPEZ GUERRA (REPSOL) & Pedro FERES (MISTRAS South America)

XXV Congresso da AIGLP28th September 2010


Acoustic Emission (AE) Acoustic Emission (AE) Basic Process and Basic Process and

DefinitionDefinitionAcoustic Emissions are transient elastic waves generated by the rapid release of energy from localized sources within a material

AE detects GROWING defects and

ACTIVE damage within the material under

loading (mechanical, thermal) orenvironmental conditions

Real time method


Defect geometriesDefect geometries

Most NDT techniques are sensitive to the orientation of defects: PT, MT, ET: surface defects UT: internal defects RT: need to be focused at the location

of the crack

AE does not depend on the orientation

AE is a volumetric, global technique for a control 100%


Acoustic Emission sourcesAcoustic Emission sources

Plastic deformation

Failure mechanisms

Phase transformation

Hydrogen embrittlement

Corrosion

Fretting

Mechanical Impacts

Leaks

Cavitation

Partial Discharges,...


AE source localizationAE source localization

Simple linear location

Planar locationUses triangular to locate source

t1 t2

32

1


AE analysis vs loadingAE analysis vs loading

Stable trend versus pressureStable trend versus pressure

Linear trend versus pressure Linear trend versus pressure

Critical trend versus pressureCritical trend versus pressure

DangerDanger


Acoustic Emission summaryAcoustic Emission summary

• Growing Defects, Real Time, • Early Detection, High Sensitivity,• Global Technique (100% volumetric)• Remote Detection,• No need to remove insulation,• Location of AE Sources,• Severity Diagnosis, • In service test, periodic or continuous,• Requalification Test (Regulations)


AFIAP Reference document in AFIAP Reference document in FranceFrance

6 different sections: SpheresSmall buried gas vesselsCylindrical pressurized equipmentsReactorsAutoclaves

Stainless steel equipments (soon)Composite materials (soon)

AE recognized by the Administration as an inspection technique and requalification method (to avoid

hydrostatic tests)


Example of applications on Example of applications on spheres and tanksspheres and tanks


• Mounded Tanks

• Buried Tanks

• Aerial Tanks

Typical storage vessel applications


Volume : 600 to 6 600 m3. More than 200 spheres ( aerial, insulated, fireproofed … ) tested by AE in France

Mounded Spheres and Vessels since 1995

Development Program to apply AE in the case of mounded vessels:

Data Base : Spheres

GOAL : Agreement from the French Department of Industry to replace the hydraulic re-test for the re-qualification of the LPG pressure equipment

Procedure for permanent installation of sensors

Design of a special AE sensor R15LPG (MISTRAS)

Test Procedure, criteria

AE testing on LPG storage tanks & AE testing on LPG storage tanks & vesselsvessels


Pressure Cycle – AE intensity

Planar Location

AE SourceAE Source

(growing (growing defect)defect)

AE sensors AE sensors networknetwork

Sensor 26

AE testing on storage spheresAE testing on storage spheres


Time

95 % MOP

105 % MOP

110 % MOP

Pressure

100 % OP

100 % MOP

98 % Pmax

30'30'

15'

10'

10'

10'

10'

10'

Pmax : Maximum Test Pressure

MOP : Maximum Operating Pressure

OP : Operating Pressure

10'

Pmax

10'

2nd Cycle

LOADING CYCLE Test Conditions : = 95 % liquid 110 % gas operating pressure

Test Conditions : = 95 % liquid 110 % gas operating pressure

AE : Typical requalification pressure cycleAE : Typical requalification pressure cycle


Practical ConsiderationsPractical Considerations

Cannot monitor properly when raining: Insulated equipment is not a problem. Possible delay to pressurization, or sheet in.

Safe access needed for sensor placement: Scaffold, abseiler, aerial lift.

Minimize extraneous noise sources, e.g.: flow restrictions close to vessel. throttling and non-return valves. turbulence and impacts connected to vessel,

use rubber or long pipe to any pump.


MONPAC procedure for spheres, MONPAC procedure for spheres, bullets, columns, etcbullets, columns, etc

• Developed by Monsanto Chemical Company in late 70’s 80’s

• Field-Proven in 1000’s of tests using follow-up NDT-(Experience based)

• Procedure adopted by ASME VIII art.12 for new vessels (without ZIP grading)

• Worldwide industry acceptance– “industry standard” per Institute Chemical Eng.

Intl. process safety working group publication


MONPAC-Outline procedureMONPAC-Outline procedure

• Asses suitability against MONPAC scope:– vessel, material, attenuation, temp., noise level

• Install and test sensors.• Monitor change in stress.• Evaluate severity of emission:

– “A” very minor source No action– “B” minor source Visual external (corrosion)– “C” source Further evaluation– “D” active source Follow-up NDT, short term– “E” intense source Immediate NDT / shut

down


CLASSE COULEUR INTERPRETATION RECOMMANDATIONS A

Green

Very minor source No action

B

Blue Minor source Visual inspection

C

Violet

Active AE source

Mid term examination with other NDT at location or other AE test

D Yellow

Intense AE source

Mid term examination with other NDT at location or other AE test Monitoring during critical service

E

Red

Critical AE sources

Assessment or shut down Inspection with other NDT technique Shut down or monitoring

Classification of zones and AE sourcesClassification of zones and AE sources

MONPAC criteriaMONPAC criteria


Severity Diagram of AE zones Position of AE zones

Propane Spheres 500m3Propane Spheres 500m3


A* : Very minor Source B* : Minor Source C* : Active Source D* : Intense Source E * : Critical Source

* IPAC Severity Grade- AE Diagnosis

AE Located Sources , Zones for recommended follow up inspection

AE Severity DiagnosisAE Severity Diagnosis

NDT Results NDT Results Ultrasonic Indications

AE Zones and Sources

180 mm Planar Defect to be repaired

PipingCorrosionVolumetric Indications

AE : a GLOBAL METHODAE : a GLOBAL METHODExample of STORAGE SPHEREExample of STORAGE SPHERE


7000 m3 propane sphere REPSOL


AE classification (bottom)AE classification (bottom)

North Sul


AE classification (top)AE classification (top)

North North


MONPAC Classification MONPAC Classification (bottom)(bottom)


MONPAC Classification (top)MONPAC Classification (top)


Conclusions of the AE test Conclusions of the AE test reportreport

During the test monitored with AE, till the maximum pressure:

Active sources of grade B have been detected, this means , no sources compromising the structural integrity of the equipment have been found.

This way the equipment is requalified for operations.

As per results of planar location, indications of the equipment where active sources have been located, which will have to be inspected through complementary non destructive testing.

The objective of this test is to control the integrity condition of the sphere and to orientate the operations management to define the inspection plan and the periodicity of future inspections.


MONPAC StatisticsMONPAC Statistics

• On-line testing– Spheres:97% pass on-line test, left in-service– Stainless: 50% have SCC requiring repair

• Hydrotest monitoring (indicates also manufacturing defects due to high stress)

• 66% of new vessels pass, failures due to:– Welding after stress relief– Inadequate weld pre-heat (high residual stress)– Poor welding

• 84% of vessels pass re-qualification hydrotest


Underground tanks Underground tanks


Volume : 32 m3Material : A48P operating: 5 bar

NATURAL GAS INPUT

Buried LPG TankBuried LPG Tank


PRESSURE LOADING CYCLEPRESSURE LOADING CYCLE(NATURAL GAS)

OP = 5 barMOP = 6 barDP = 14 barAE MaxP = 14 bar

90% Liquid LPG




GLOBALGLOBALEMISSIVITYEMISSIVITY

Cycle

Amplitude

Intensity

Activity


Underground Tank 30 MUnderground Tank 30 M33

Permanent installationof AE sensors


AFIAP – GEA – Annex 4AFIAP – GEA – Annex 4

DOMESTIC LPG VESSELSDOMESTIC LPG VESSELS

- Buried- Carbon steel (A42, A48, A52)- Volume < 12 m3

50 2 cmentre-axe

pressurisation

capteur

capot



Pressurisation

2250 mm 2250 mm

Capteurs50 ± 2cm

Maille 1 Maille 2 Maille 3

Zone couverte par la maille n°1


Distances maximalessource-capteur 2400 mm



Pressurisation

2250 mm 2250 mm

Capteurs50 ± 2cm

Maille 1 Maille 2 Maille 3






Dia : 1.2 mL : 7.2 mV : 7.3 m3



Capteur instrumenté

50 ± 2 cm 50 ± 2 cm

Zones couvertes parles mailles 1 et 2

Zones couvertes par lesmailles 3 et 4

Maille 1

Maille 3 Maille 4

Maille 2



PS

EXAMPLE OF PRESSURE CYCLE


CONCLUSIONSCONCLUSIONS

• AE is the only global NDT method to control the integrity of pressurized equipment in service

• No stop of service, no loss of product• Several thousands of structures have been

tested, and the technique is clearly mature• Acoustic Emission Testing is recognized by

the authorities in many countries to re-qualify pressure equipments

Documents

Copyright © 2010 Proprietary Information: no dissemination, use or duplication allowed “Maximizing cylinder life cycle” Avoiding hydrostatic testing and