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 AIGLP 28 th September 2010

Copyright © 2010 Proprietary Information: no dissemination, use or duplication allowed Acoustic Emission (AE) Basic Process and Definition Acoustic 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) or environmental conditions  Real time method

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

Copyright © 2010 Proprietary Information: no dissemination, use or duplication allowed Acoustic Emission sources  Plastic deformation  Failure mechanisms  Phase transformation  Hydrogen embrittlement  Corrosion  Fretting  Mechanical Impacts  Leaks  Cavitation  Partial Discharges,...

Copyright © 2010 Proprietary Information: no dissemination, use or duplication allowed AE source localization  Simple linear location  Planar location  Uses triangular to locate source t1 t

Copyright © 2010 Proprietary Information: no dissemination, use or duplication allowed AE analysis vs loading Stable trend versus pressure Linear trend versus pressure Critical trend versus pressure Danger

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

Copyright © 2010 Proprietary Information: no dissemination, use or duplication allowed AFIAP Reference document in France 6 different sections:  Spheres  Small buried gas vessels  Cylindrical pressurized equipments  Reactors  Autoclaves  Stainless steel equipments (soon)  Composite materials (soon) AE recognized by the Administration as an inspection technique and requalification method (to avoid hydrostatic tests)

Copyright © 2010 Proprietary Information: no dissemination, use or duplication allowed Example of applications on spheres and tanks

Copyright © 2010 Proprietary Information: no dissemination, use or duplication allowed Mounded Tanks Buried Tanks Aerial Tanks Typical storage vessel applications

Copyright © 2010 Proprietary Information: no dissemination, use or duplication allowed  Volume : 600 to m 3.  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 & vessels

Copyright © 2010 Proprietary Information: no dissemination, use or duplication allowed Pressure Cycle – AE intensity Planar Location AE Source (growing defect) AE sensors network Sensor 26 AE testing on storage spheres

Copyright © 2010 Proprietary Information: no dissemination, use or duplication allowed Time 95 % MOP 105 % MOP 110 % MOP Pressure 100 % OP 100 % MOP 98 % Pmax 30' 15' 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 AE : Typical requalification pressure cycle

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

Copyright © 2010 Proprietary Information: no dissemination, use or duplication allowed MONPAC procedure for spheres, bullets, 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

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

Copyright © 2010 Proprietary Information: no dissemination, use or duplication allowed Classification of zones and AE sources MONPAC criteria

Copyright © 2010 Proprietary Information: no dissemination, use or duplication allowed Severity Diagram of AE zones Position of AE zones Propane Spheres 500m3

Copyright © 2010 Proprietary Information: no dissemination, use or duplication allowed 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 Diagnosis NDT Results Ultrasonic Indications AE Zones and Sources 180 mm Planar Defect to be repaired Piping Corrosion Volumetric Indications AE : a GLOBAL METHOD Example of STORAGE SPHERE

Copyright © 2010 Proprietary Information: no dissemination, use or duplication allowed 7000 m3 propane sphere REPSOL

Copyright © 2010 Proprietary Information: no dissemination, use or duplication allowed AE classification (bottom) North Sul

Copyright © 2010 Proprietary Information: no dissemination, use or duplication allowed AE classification (top) North

Copyright © 2010 Proprietary Information: no dissemination, use or duplication allowed MONPAC Classification (bottom)

Copyright © 2010 Proprietary Information: no dissemination, use or duplication allowed MONPAC Classification (top)

Copyright © 2010 Proprietary Information: no dissemination, use or duplication allowed Conclusions of the AE test report 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.

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

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

Copyright © 2010 Proprietary Information: no dissemination, use or duplication allowed Volume : 32 m3 Material : A48 P operating: 5 bar NATURAL GAS INPUT Buried LPG Tank

Copyright © 2010 Proprietary Information: no dissemination, use or duplication allowed PRESSURE LOADING CYCLE (NATURAL GAS) OP = 5 bar MOP = 6 bar DP = 14 bar AE MaxP = 14 bar 90% Liquid LPG Buried LPG Tank

Copyright © 2010 Proprietary Information: no dissemination, use or duplication allowed Buried LPG Tank GLOBALEMISSIVITY Cycle Amplitude Intensity Activity

Copyright © 2010 Proprietary Information: no dissemination, use or duplication allowed Underground Tank 30 M 3 Permanent installation of AE sensors

Copyright © 2010 Proprietary Information: no dissemination, use or duplication allowed AFIAP – GEA – Annex 4 DOMESTIC LPG VESSELS - Buried - Carbon steel (A42, A48, A52) - Volume < 12 m3 50  2 cm entre-axe pressurisation capteur capot

Copyright © 2010 Proprietary Information: no dissemination, use or duplication allowed AFIAP – GEA – Annex 4 Dia : 1.2 m L : 7.2 m V : 7.3 m 3

Copyright © 2010 Proprietary Information: no dissemination, use or duplication allowed AFIAP – GEA – Annex 4

Copyright © 2010 Proprietary Information: no dissemination, use or duplication allowed AFIAP – GEA – Annex 4 PS EXAMPLE OF PRESSURE CYCLE

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