Oslo 24.11.2008 Seminar for NDT Nivå 3 - Personell Low Frequent Eddy Current (Lavfrekvent virvelstrøm) Arild Solberg Mohan Kang
Oslo 24.11.2008 Nivå 3 Seminar Content: Introduction History Technology & Reporting Principles Equipment Applications Practical demo of technology
Introduction: Eddy Current Technology (EC)
Eddy Current Technology (EC), Standard equipment
Eddy Current Technology (EC), Special equipment Heat Exchanger & Boiler Tube Inspection Heat exchangers Coolers Boilers Condensers Reactors Air coolers Separators Heaters Air-condition systems etc.
Low Frequent Eddy Current (Lavfrekvent virvelstrøm) Named: SLOFEC Saturation Low Frequency Eddy Current The fast inspection screening method for defect detection
History: SLOFEC Saturation Low Frequency Eddy Current
1993 Problem: Inspection of Nuclear Power Plant - underground cooling water pipes from inside without removal of inner coating, detecting external corrosion Pipe O.D. up to 4m Pipe wall thickness up to 32mm Inner coating thickness ~ 3-4mm, epoxy type Detected defects Ext. defects from 30% wall Loss
1996 Problem: Inspection of buried and half buried storage vessels from inside, detecting external corrosion 55% reduction of inspection costs Storage vessel : Ø ~ 4.500mm; WT 18mm Detected defects: ext. defects 30%, corrosion Time for inspection: ~ 3 shifts per vessel Entrance : Ø 550mm manhole
1997 World Wide evaluation of Petroleum Association of Japan Evaluation: Tank floor inspection methods / systems Criteria: Success: sensitive, economical, handling SLOFEC evaluated for inspection regulation by laboratory and field tests TEST RESULTS: Plates wt 9mm, 12mm, 21mm Coating 1-3mm Smallest detected underside defects: wt 9mm - Ø 2mm, depth 20% wt 12mm - Ø 2mm, depth 20% wt 21mm - Ø 4mm, depth 20%
2000 SHELL - Expro Brent Field Project: Inspection of Oil Rundown Lines in concrete legs Evaluation of SLOFEC Pipe Scan sensitivity - result : qualified Success: Inspection of pipes up to OD 30 ; up to wt 26mm coatings/wrap. up to 5mm
Main targets for SLOFEC inspections are: - Detection & identifying of localised corrosion areas (sensitive to localised defects, pitting, MIC, etc.) - Fast scanning to receive a quick condition overview - Scanning through coatings to avoid removing it 2.500 2.000 1.000 Scan Length 0 360 270 180 90 0 Pipe Circumference
Technology & Services Corrosion Detection & Screening Corrosion detection & screening at Tanks, Vessels, Separators Pipes, Pipelines, etc. with SLOFEC Technology
Technology & Reporting Principles: SLOFEC Saturation Low Frequency Eddy Current
MAGNET EDDY CURRENT SENSORS TEST PIECE MAGNETIC FIELD LINES DEFECT COMPRESSE D MAGNETIC FIELD LINES
Response of the Differential Eddy Current Coil System (with SLOFEC ) ) to detect Local Defects Scan direction SignalAmplitude Signal Response of the Differential Channel
SLOFEC inspection makes use of Eddy Current Differential Channel for detection of localized material changes (Defects) Signal response to a local and gradual defect
SLOFEC Calibration with artificial reference defects Comparison Method - Calibration Evaluation of indications in comparison to calibration
SLOFEC Sensitivity Test
SLOFEC Accuracy Test Defect Depth evaluated by the SLOFEC System [% of the nominal wall thickness] 100% Ground Truth Diagram 80% 60% 40% 20% 20% P16 P7 P4 P21 P1 P11a&b P8 P5 P10a P2 P12a&b 40% 60% 80% 100% mechanic measured defect depth [% of the nominal wall thickness] P9 P3 P6 Ground Truth Diagram for comparison SLOFEC evaluated to measured defect depth performed with SHELL Global Solutions (Amsterdam) example: plate thickness 18mm material ST35.8
SLOFEC Confirmation of Detected Defects Tank floor: Plate thickness: Coating : Defects : Confirmed : Chemical Plant 12mm Rubber, 10mm thick Corrosion pits from underside, 20-30% loss, additional through holes found by UT
SLOFEC Distinction - Underside / Topside Defects Signal display of UNDERSIDE DEFECTS Artificial defect (dia. 10mm) at the underside side depth 40% VERTICAL SIGNAL ORIENTATION Signal display of TOPSIDE DEFECTS Topside corrosion Corrosion pit diameter 15mm, depth 20% HORIZONTAL SIGNAL ORIENTATION
SLOFEC Field inspection results compared to UT results Project: Result comparison UT mapping, - SLOFEC results - UT re-inspection results of SLOFEC detected defects Object: Offshore knock out drum (wt 25mm) mm 30 25 20 15 10 5 0 SLOFEC Comparison 1 2 3 4 5 6 7 8 9 10 11 12 13 14 15 16 17 18 Grid No AEA min SLOFEC SLOFEC Comparison mm 30 25 20 15 10 5 0 AEA min SLOFEC SLOFEC UT 1 3 5 7 9 11 13 15 17 Grid No
Relative Sensitivity Curve, in comparison to MFL Relative Detection Sensitivity MFL SLOFEC 2 4 6 8 10 12 14 16 18 20 22 24 26 28 30 32 34 36 Wall thickness [mm] WT 2d d d / WT = detect ability [%]
SCANNING SOFTWARE & REPORTING
Scan & Scan Imaging Software Scan Software Indication - display while scanning or Scan Imaging Software for coloured condition imaging
Colour Imaging - Defect Classification COLOUR PALETTE DEFECT CLASSIFICATION: Display of indication amplitude analysis, representing wall loss in comparison to reference < 20% 20-30% 30-40% 40-50% >50%
Colour Imaging - Tank Floor Inspection Tank Floor Scan Defect Mapping Colour details for defect imaging
Colour Imaging - Tank Floor Inspection Tank floor- Single Plate Scan Report Colour details for defect imaging Including details of UT - verified indications
Colour Imaging - Pipe Inspection Distance to GTF [meter] 13 14 Flange Weld (FW) 15 16 17 Section 1 2.230mm 18 24 19 25 20 26 21 27 22 28 23 29 30 31 32 33 34 Section 2 1.900mm Top of steel (TOS) < 20% 20-30% 30-40% 40-60% > 60% Section 3 3.685mm Colored defect map from a inspected pipe section Section 4 2.720mm Section 5 450mm Signal of the reference internal defect (50%depth) in the signal Y- component / phase analyse window Client : OIL COMPANY Location : REFINERY Subject : Oil Rundown Lines Section : 4 Date : July/Agust 2000 K-No. : 105/00 Pipe Identif. : P-53 TM SLOFEC - PipeScan Report
Colour Imaging - Pipe Inspection Scan Direction Length Position Uninspected area Longitudinal Weld Axial direction Length 2.000mm Diameter of the pipe : 30 < 20% 20-30% 30-50% 50-70% > 70% Support Beam Signal component Y-axis set for indications of subsurface corrosion
Colour Imaging - Defect Progression Scan - Inspection 1 2.500 Scan - Inspection 2 2.500 2.000 2.000 1.000 Scan Length 1.000 Scan Length 360 270 180 Pipe Circumference 90 0 0 360 270 180 Pipe Circumference 90 0 0
Equipment: SLOFEC Saturation Low Frequency Eddy Current
SLOFEC Equipment Computerized ET System Pole Shoes, Sensors Wheels Scanners
Tank floor Scanner FS400 SLOFEC Floor Scanner 400mm width 8 EC Sensors SLOFEC eddymax computerized eddy current system
Tank floor Scanner FS400 FEATURES: Materials: fe- and n-fe materials Plate thickness: up to 32 mm (fe( fe-materials) Coating types: all electr.. non conductive Coating thickness: up to 10 mm (field experience) Operation: 2 men Cleaning: free of mud / broom cleaned Scan-coverage: coverage: dead zones - edges Defect detection: in bear metal, in overlapped plates, at annular plates up to 30 mm distance to the shell Productivity: depending of tank size ~ 400m² - 600m² /shift
Tank floor Scanner FS300 FEATURES: Materials: fe- and n-fe materials Plate thickness: up to 15 mm (fe( fe-materials) Coating types: all electr.. non conductive Coating thickness: up to 6 mm (field experience) Operation: 2 men Cleaning: free of mud / broom cleaned Scan-coverage: coverage: dead zones - edges Defect detection: in bear metal, in overlapped plates, at annular plates 15 mm Productivity: depending of tank size ~ 300m² - 500m² /shift
Pipe Scanner PS 200 Type: Input : WT Range: Adapt ions: Electromagnet 110/220V AC up to 26mm 4 to flat
Pipe Scanner LS 150 Type: Electro Magnet WT Range: up to 18mm Adapt ions: 4 4 to flat
Pipe Scanner LS 120 Type: Permanent Magnet WT Range: up to 12,5mm Adapt ions: 2 2 to flat
Pipe Scanner LS 100 Type: Permanent Magnet WT Range: up to 9mm Adapt ions: : 1 1 to flat
Scanner TWC 20 Self driving scanner for i.e. vertical surfaces
SLOFEC Sub sea Scanner Target: Inspecting Riser Pipe/Caissons through Coatings & Marine growth Test Results e.g.: 12 Pipe x WT 20mm, Coating 15mm Detected Internal pits: Ø 15mm, detected from 20% wall loss
Internal pipe inspections, examples Eddy Current & SLOFEC Internal Internal Pipe Scanner i.e. 16 pipe
Applications: SLOFEC Saturation Low Frequency Eddy Current
TANKFLOOR INSPECTION
Inspection of Storage Tanks Tank floors
Inspection of Storage Tanks - walls
PIPE INSPECTION
Pipe Scanning - Examples Target: Screening of pipe bottom Pipe: 24 Naphtha Line ; WT : 1/2 Detected defects: 20% wall loss from inside, Ø 4mm, mainly CO² corrosion 6`clock line Time of inspection: ~ 15 min. for 9m (180 coverage)
Pipe Scanning - Examples Process pipe work
Pipe Scanning - Examples Inspection at temperature 80 C Target: Detection of MIC (Micro Biological Corrosion) in early stage. A tool as early warning of corrosion Pipe dia.: 16 WT: 13mm Detected defects: Time of inspection : 15% wall loss from inside 2-3mm in diameter 20min. for 6m (360 coverage)
Pipe Scanning - Examples Target: Internal corrosion screening / detection of galvanised fire water pipes Pipes: ~ 2 2-10 ; WT : up to 9mm Detected defects: 20% - 30% int. wall loss, from ~ Ø 3mm
Pipe Scanning - Examples Target: Pipe: Detected defects : Time of inspection : Screening of furnace tubes from outside 6 Furnace Tube; WT : 9mm 20% int. wall loss, from Ø 3mm, massive corrosion at furnace side ~ < 10 min. for 12m (180 coverage)
PIPE INSPECTION Example scanning speed
Pipe Scanning - Examples Project: Success: Inspection of Oil Rundown Lines in concrete legs Evaluation of SLOFEC Pipe Scan sensitivity - result : qualified Inspection of pipes up to OD 30 ; ; up to wt 26mm coatings/wrappings up to 5mm
Pipe Scanning - Examples Pipe work inspected by SLOFEC, in the shaft of a concrete platform structure
Pipe Inspection Project reporting
Pipe Scanning - Examples Sea water lift Caissons inspection performed with SLOFEC Technology
Pipe Scanning - Examples Example Inspection of Caissons
Pipe Scanning - Examples Cup-type Pits Sandblasted internal pipe surface with detected MIC Pit Clusters
Pipe Scanning - Examples Cut of pipes with chloride corrosion Target: Stainless Steel Pipes (Offshore) Chloride corrosion detection and depth determination Pipes: 1-10 ; WT : up to 11mm Detected defects: Chloride Corrosion from 20% - 30% wall loss
VESSEL & TANK INSPECTION
Vessel Inspection - Examples Vessel: Production Vessel Ø 2.800mm; WT: 13mm; Temp.: 120 C Detected defects : Isolated pits 20% int. wall loss from Ø 4mm,
Vessel Inspection - Examples Vessel : Detected defects: Time for inspection: Knockout Drum (offshore) Ø 2.600mm; WT : 25-28mm 28mm internal stainless steel liner Internal defects 30% int. wall loss, isolated pits, cor. areas 3-4 shifts for 2 drums
Vessel Inspection - Examples
SLOFEC CONCLUSION
Conclusion of SLOFEC - Fast corrosion screening method for local metal loss - Inspection of thick wall components (up to 32 mm) - Inspection through thick coating (up to 10 mm) - High defect detection sensitivity - Distinction between topside and bottom defects - Colored condition mapping - High potential for additional applications - Inspection at higher temperatures (experience up to 130 C) - Inspection of Fe - & Non Fe Materials (CS, Duplex, Stainless)
Other applications by use of SLOFEC - Sub sea inspections (Riser pipes, Caissons, etc.) - Spherical tank inspection - Duplex Material Inspection - Internal pipe inspections
SLOFEC DUPLEX / SUPER DUPLEX PipeScanning - Examples Sensitivity Test at Duplex & Super Duplex Pipes 10 x WT 4.19mm Smallest internal defect detected: Ø 2mm, Depth 24% 4 x Ø 3mm TWH 4 x Ø 5mm TWH Ø 3mm D 3mm Ø 2mm D 3mm Ø 2mm D 3mm Ø 8mm D 9mm Ø 3mm D 12mm Ø 5mm D 12mm Ø 8mm D 12mm
Technology & Services For further information, kindly contact: KTN AS Fjøsangervn. 50 P.Boks 6078 Postterminalen 5892 Bergen NORWAY Phone: + 47 55205300 E-mail: post@ktn.no www.ktn.no