development of a magnetic sensor for detecting and … sensor...development of a magnetic sensor for...

Development of a Magnetic Sensor for Detecting and Sizing Paraffin Deposition Inside Pipelines

Professor Dr. João Rebello (UFRJ)MSc. Claudio Camerini (Petrobrás)Eng. Ivan Vicente Janvrot (Pipeway)Dra. Maria Cristina López Areiza (LNDC/UFRJ)

ENGINEERING OF METALLURGICAL AND MATERIALS

VENKATESAN, R., NAGARAJAN, N.R., PASO, K., et al, “The strength of paraffin gels formed under static and flow conditions”, Chemical Engineering Science, v.60, pp. 3587 – 3598, 2005.

Pipe

Paraffin

The paraffin deposit reduces the oil flow effiency in the pipe, by reducing its inner diameter.


Motivation

Many companies use PIGs (Pipeline Internal Gate).

This equipment is used in several operations: defect detection, cleaning and paraffin removal from the pipe inner wall.

These operations must be periodic to avoid flow obstruction in the pipe.

Cleaning PIG Geometrical PIG Magnetic PIG

Typical distribution of sensors: called crown


Motivation

Development of a magnetic basedmethodology for:-detecting and sizing paraffin depositson the pipeline inner wall and;-detecting and sizing corrosion attack areas located underneath the paraffin deposits.

ObjectivesENGINEERING OF METALLURGICAL AND MATERIALS

-to develop a specific sensor to beadapted to the equipment calledPipeline Internal Gate (Pig), fordetecting and sizing such paraffindeposition areas.

ObjectivesENGINEERING OF METALLURGICAL AND MATERIALS

Magnetic Flux lines duringa MFL inspection :

(a) Low magnetizationlevel, not suitable;

(b) Medium magnetizationlevel;

(c) High magnetizationlevel, suitable.

Currrently used techniques for metal loss detection due to corrosionattack based on magnetic principles:

The typical technique is Magnetic Flux Leakage (MFL)

NESTLEROTH, B., “Technology Status Assessment for Circumferential MFL for SCC”, Final Report on RESEARCH PROGRAM PR39420, 1999.

Source: www.netl.doe.gov/scng/


References

-Different carbon steels can exhibit rather different magnetic responses




Reference

- How to detect defects and corroded areas using MFL and PIG’s?




ReferenceDefect detectionconsists in findingthe areas in the pipewhere there is a MFL due to metal loss.One can see thedrive section, thebrushes for cleaning andmagentic contact, the sensors anddevice for data adquisition.

Besides the longitudinal orientation ofthe magnetic flux lines, it is also possibleto use a perpendicular magnetic field.

GLADCHTEIN, R. S., “Solução do Problema Inverso Magnetostático Utilizando Elementos Finitos e Técnicas de Otimização”, PhD Theses, PUCRio, 2002.

Alternative ways of magnetic induction can beconsidered.

ReferenceENGINEERING OF METALLURGICAL AND MATERIALS

BOECHAT et Al., “Development of a magnetic sensor for detection and sizing of internalpipeline corrosion defects”, NDT&E International , Vol 42 , Pag, 669–677, 2009.

Perpendicular magnetic induction was succesfully used for crack detection and sizing

Based on Gladchtein´s work, Boechat et all (2009) developed anew magnetic sensor with perpendicular magnetic flux, called bythe authors, Internal Corrosion Sensor (ICS). The focus was onthe detection and sizing of small internal defects in thick wallspipelines.


BOECHAT et Al., “Development of a magnetic sensor for detection and sizing of internalpipeline corrosion defects”, NDT&E International , Vol 42 , Pag, 669–677, 2009.

-It was confirmed the big potential of the magnetic vertical induction as technique for detection of small internal defects


1. To develop computational models for themagnetic flux density behavior perturbation inthe pipelines wall. These values were obtainedby simulations with FEMM and OPERA software.The focus was to obtain the best signal contrastfor the sizing of paraffin deposits.

2. To design, to build and to test a prototype probe.3. To search for the best parameters of the probe

sensor Hall aiming to attain high sensitivity.4. To set up calibration curves for paraffin deposits

sizing.

MethodologyENGINEERING OF METALLURGICAL AND MATERIALS

OPERA 3D Cobham

FEMMFinite Element Method Magnetics

Operational principle

Steel


Operational principles

Steel


The operational principle consists in creating a constantmagnetic field close to the internal wall of the pipe, usinga permanent magnet.The magnetic density flow lines are measured by a Hallsensor, placed between the magnet and the internal pipewall.The presence of paraffin reduces the density of themagnetic flow detected by the Hall sensor.

Computational Model

Magnet coercivity= 35mgoe

Isotropic and linear material settings

Steel 1020 permeability=> μ = 760

Steel conductivity= 5.8 MS/m

Steel size= 100x100x5 mm

Nodes = 71435

Mesh elements= 216096

OPERA 3D - Cobham

FEMM – 2D


Sensor position

Sensor position

Sensitivity was evaluated as function of the probe sample distance

0 2 4 6 8 10

0.060

0.065

0.070

0.075

0.080

0.085

0.090

B (T

)

H (mm)

Magnetic Flux Density at the Hall sensor position

B(T)

B(T)

Field aquisicion point (Hall Sensor)

STEEL STEEL

Magnet

Magnet

H: Distance from the pipe internal wall and the Hall sensor

LB: Value of B(T) measured by the Hall sensor when in contact with the steel plate .

LB (H=0)

Study of Magnetic SensitivityENGINEERING OF METALLURGICAL AND MATERIALS

Prezentator

Notatki do prezentacji

Sensitivity was evaluated as function of the probe sample distance

0 2 4 6 8 10

0.060

0.065

0.070

0.075

0.080

0.085

0.090

B (T

)

H (mm)

Magnetic Flux Density at the Hall sensor position

B(T)

B(T)


STEEL STEEL

Magnet

Magnet

Even for big distance (8 to 10mm) the magnetic fluxdensity is high enough. Thismeans that the parametersselected are appropriate. Thefigure shows that the Hallsensor is not in a magneticsaturated condition.

LB (H=0)

Study of Magnetic SensitivityENGINEERING OF METALLURGICAL AND MATERIALS

Prezentator

Notatki do prezentacji

Magnetic flux was measured B(Gauss) experimentally and compared with OPERA 3D simulation results.

H

Gaussmeter

Point of the magnetic flux density measurement, B(Gauss).

Spacer´s Height

Level of magnetismENGINEERING OF METALLURGICAL AND MATERIALS

Comparison of B (Gauss) for different spacer´s values (H).

SimulationValidation

H Spacer´s Height

(mm)

B (G)(Experimental)

B (G)(OPERA3D)

to 2mm∆

(Error)

8 185 198 6,5%

7 220 230 4,3%

6 246 270 8,8%

5 295 319 7,5%


There is a good correspondance between the experimental andsimulated results for the magnet initially chosen (35 MGOe). The maximum error in the table is lower than 10 %.

Interference Among ProbesThe interference between the sensors signals was evaluated in the X and Y directions in the crowns.

0 20 40 60 80 100 120 140 1600.90

0.92

0.94

0.96

0.98

1.00

B/LB

X (mm)X(mm)

Fixed sensorMoving sensor

X(mm)


Y(mm)

The crowns

X direction

The influence can beneglected for Xgreater than 70mm

LBB

•Vertical interference among sensors.

0 2 4 6 8 10

1.00

1.02

1.04

1.06

1.08

Probe 2 Probe 3

B/LB

Z (mm)

A

0 2 4 6 8 10

1.00

1.02

1.04

1.06

1.08

Probe 1 Probe 3

B/LB

Z (mm)

BY (mm)


1

1

2 3

2 3

Z (mm)

Z (mm)

Interference Among Probes

•Vertical interference among sensors.

0 2 4 6 8 10

1.00

1.02

1.04

1.06

1.08

Probe 2 Probe 3

B/LB

Z (mm)

A

0 2 4 6 8 10

1.00

1.02

1.04

1.06

1.08

Probe 1 Probe 3

B/LB

Z (mm)

B


1

1

2 3

2 3

Z (mm)

Z (mm)

Interference Among ProbesFrom figure A the moving sensor is placed at the extremity of thecrown. There is a clearinterference on sensors 1 and 2, but not for the sensor 3. Whenthe moving sensor is in a middleposition in the crown, figure B, the moving sensor does interfere on the signal sensors 1 and 3 but in the same way. This isthe real case in the PIG crown.

From the simulated results below it is possible to define 4 mm as themaximum paraffin thickness enabling crack detection.

-30 -20 -10 0 10 20 30

0.75

0.80

0.85

0.90

0.95

1.00

1.05

B/LB

Distance to the center of the defect (mm)

H = 0mm H = 2mm H = 4mm H = 6mm

B : Magnetic flux density

Defect depth = 3 mm


Wax H

Material LossENGINEERING OF METALLURGICAL AND MATERIALS

Is it possible to detect defects beneath the paraffin layer?

B and LB Magnetic flux density of thesensor WITH and WITHOUT paraffin layer

-30 -20 -10 0 10 20 300,80

0,85

0,90

0,95

1,00

1,05

B/LB

X (mm)

L = 16mm L = 8mm L = 4mm L = 2mm

Excessive Material A weld bead could represent what is called “excessive material”or a bump on the pipe inner surface.

What is the effect of thesize of the probe tip on thesensor response when itmoves over a weld bead?

The smaller the probe tipthe higher the possibilityof surface scractching.L= 4mm is the ideal probetip dimension.


L L

FEMM – 2D

-30 -20 -10 0 10 20 300,80

0,85

0,90

0,95

1,00

1,05

B/LB

X (mm)

L = 16mm L = 8mm L = 4mm L = 2mm

Study of excessive materialThe excessive material could be interpreted as a weld.

It was studied the effect of the size of the base of the sensor in the response when passing through an excessive material metal area.


L L

FEMM – 2D

10 mm

Prototype Probe Construction

MLX90242: Linear Hall Effect SensorNdFeB magnets:grade N35Material of the Structure: Stainless Steel (non magnetic)

B



Prototype Probe Construction

PrototypeTesting

H=0, without Wax deposition

H=1mm of wax´s deposition H=4mm of wax´s deposition

Dielectric material used as Wax

Depth of the circular defects = 3,6,9,12,15 mm

A carbon steel plate with known defects was used.The focus was not to reconstruct the shape of the defect but toevaluate the ability of the sensor to detect the different defect depths.


Displacement direction

Prototype ProbeTest

H=0, without paraffin layer

H=1mm H=4mm

Dielectric material used to simulate paraffinThickness H

Circular defect depth = 3, 6, 9, 12, 15 mm

A carbon steel plate with defects was used. The focus was to assessthe ability of the sensor to detect defect at different depths.


Scanning direction

500 600 7001,71,81,9

2,02,1

2,22,3

2,42,5

2,62,7

2,82,9

3,0

Paraffin wax deposit height

Hall Sensor Sensibility

None (0mm) None (0mm)

B

Tempo

22,5mV/mT

4000

1,8

2,0

2,2

2,4

2,6

2,8

3,0


Hall Sensor Sensibility22,5mV/mT

1mm 1mm

B

Tempo

2000

1,8

2,0

2,2

2,4

2,6

2,8

3,0



B

Tempo

4mm 4mm

500 550 6001,71,81,9

2,02,1

2,22,3

2,42,5

2,62,7

2,82,9

3,0

Paraffin wax deposit heightHall Sensor Sensibility55mV/mT1 Tempo direto direto direto 600 700 8001,71,81,92,02,12,22,32,42,52,62,72,82,93,0 Paraffin wax deposit heightHall Sensor Sensibility55mV/mT1 Tempo 1mm 1mm 1mm 800 9001,82,02,22,42,62,83,0 Paraffin wax deposit heightHall Sensor Sensibility55mV/mTB Tempo 4mm 4mm 4mm350 400 4501,71,81,92,02,12,22,32,42,52,62,72,82,93,0 Paraffin wax deposit heightHall Sensor Sensibility72,5mV/mT1 Time direto direto direto 400 450 500 5501,71,81,92,02,12,22,32,42,52,62,72,82,93,0 Paraffin wax deposit heightHall Sensor Sensibility72,5mV/mT1 Tempo 1mm 1mm 1mm 200 300 4001,71,81,92,02,12,22,32,42,52,62,72,82,93,0 Paraffin wax deposit heightHall Sensor Sensibility72,5mV/mT1 Tempo 4mm 4mm 4mmSTEEL STEEL WAXSENSOR SENSORSensitivity AnalysisENGINEERING OF METALLURGICAL AND MATERIALS

500 600 7001.71.81.9

2.02.1

2.22.3

2.42.5

2.62.7

2.82.9

3.0

Paraffin deposit height

Hall Sensor Sensibility

None (0mm) None (0mm)

B

Tempo

22,5mV/mT

4000

1.8

2.0

2.2

2.4

2.6

2.8

3.0

Paraffin deposit height


1mm 1mm

B

Tempo

2000

1,8

2,0

2,2

2,4

2,6

2,8

3,0



B

Tempo

4mm 4mm

500 550 6001,71,81,9

2,02,1

2,22,3

2,42,5

2,62,7

2,82,9

3,0


Hall Sensor Sensibility55mV/mT

1

Tempo

direto direto direto

600 700 8001,71,81,9

2,02,1

2,22,3

2,42,5

2,62,7

2,82,9

3,0



1

Tempo

1mm 1mm 1mm

800 900

1,8

2,0

2,2

2,4

2,6

2,8

3,0



B

Tempo

4mm 4mm 4mm

350 400 4501,71,81,9

2,02,1

2,22,3

2,42,5

2,62,7

2,82,9

3,0



1

Time

direto direto direto

400 450 500 5501,71,81,9

2,02,1

2,22,3

2,42,5

2,62,7

2,82,9

3,0



1

Tempo

1mm 1mm 1mm

200 300 4001,71,81,9

2,02,1

2,22,3

2,42,5

2,62,7

2,82,9

3,0



1Tempo

4mm 4mm 4mm

STEEL STEEL

WAXSENSOR SENSOR

Sensitivity Analysis


Sensors Array Nylon blocks used to simulate paraffin

First tests with array systemSetup ready at Pipeway Company. ENGINEERING OF

METALLURGICAL AND MATERIALS

0.0 0.5 1.0 1.5 2.0 2.5 3.0 3.5 4.0 4.50.75

0.80

0.85

0.90

0.95

1.00

Experimental data Simulated [FEMM] data Simulated [OPERA] data

B/LB

h [mm]

ResultsENGINEERING OF METALLURGICAL AND MATERIALS

H: Different heights of nylon blocks (to simulate paraffin)

A prototype probe for detection and sizing paraffin height at the inner surface of steel pipelines was designed.It also showed to be able to detect defects on the pipeline located beneath the paraffin layer.

ConclusionsENGINEERING OF METALLURGICAL AND MATERIALS

To evaluate the answer of an array of sensors in a precision setup.

Future worksENGINEERING OF METALLURGICAL AND MATERIALS

Professor João M. A. Rebello

[email protected]

LNDC - Laboratory of Nondestructive Testing, Corrosion and Welding

Department of Metallurgical and Materials Engineering, Federal University of Rio of Janeiro, Rua Pedro Calmon

SN, Cidade Universitária. CEP 21941-596, Rio de Janeiro, Brazil.

Questions?ENGINEERING OF METALLURGICAL AND MATERIALS

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