Title: I began my career in the Petrochemical and Refinery industry 27 years ago' I am currently employed b
1Introduction
- I began my career in the Petrochemical and
Refinery industry 27 years ago. I am currently
employed by Acuren Inspection Services (Formally
known as Longview Inspection Services), as
Manager of Advance Services Tubing Inspection
Group for the last 12 years, and a certified
Level- III in Eddy Current. I host mock-up test
qualification for numerous plants and facilities
throughout the United States in locations such
as Electrical Power Research Institution (EPRI)
Lyondell/Equistar ShellMotiva Chevron BP
Corporation Bayer Corporation Valero Refinery,
etc. I have developed testing applications and
procedures for a multitude of tubing application
needs in todays industry, which I feel share a
lot of experience and knowledge in the Advance
Tubing Service.
2DISCUSSION OF ADVANCE TECHNOLOGIES FOR CARBON
STEEL HEAT EXCHANGER TUBING
3INTRODUCTION
- Refinery and Chemical plants can employ hundreds
of heat exchangers or condensers in a single
process unit, each having its unique process,
service and damage mechanism. - Heat exchanger tubing is subjected to process
chemistry on both sides (I.D. O.D.) such as
water, steam, process, or even air. - This fluid and heat transfer conditions,
contributes to either process corrosion and/or
mechanical damage within the heater exchanger
such as corrosion, thinning, pitting, cracking,
erosion, vibration or a combination of those
mentioned.
4Introduction Inspection Techniques
- NDE techniques which are most common and
currently being used in the industry include
(ET) Eddy Current, (RFT) Remote Field Testing,
(IRIS) Internal Rotating Inspection System, (MFL)
Magnetic Flux Leakage (SteelTest). - The discussion today will focus on three of most
commonly used tube inspection applications for
ferrous materials (Remote Field Testing, IRIS,
and MFL), along with the advantages and
disadvantages associated with each test. - Also, several other new and emerging technologies
will briefly be discussed RFT Array Coils X-RFT
(External Reference Remote Field Testing).
5WHY PERFORM TUBE INSPECTION?
- Component Reliability Safety Environment
- Reliability Reduce the Chance of Unscheduled
Downtime lost revenue. - Predictive Maintenance Determine Corrosion
Rate/Remaining Life Calc., Trending - Failure Analysis Provides data for prevention of
future failures - Quantitative Data Hydro-Test is not sufficient.
Bore-scope inspection can be
misleading, limited to visual examination.
6REMOTE FIELD TESTING (RFT)
7REMOTE FIELD TESTING (RFT) PRINCIPLE
- REMOTE FILED TESTING IS AN ELECTROMAGNETIC
TECHNIQUE THAT UITILIZES AC EXCITATION TO
GENERATE AC MAGNETIC LINES OF FLUX. - A THROUGH WALL TRANSMISSION WHICH IS DETECTED 2-3
TUBE DIAMETERS AWAY BY INDUCING A VOLTAGE INTO
PASSIVE SENSORS. - WITHOUT ANY MAGNETIZATION OR SATURATION.
- RFT PROBES CONTAIN TWO TYPES OF COILS USED
COMMONLY IN A SINGLE OR DUAL ARRANGMENT. - ONE COIL IS THE EXCITER COIL, WHICH TRANSMITS AN
ELECTROMAGNETIC FIELD THROUGH THE TUBE WALL AND
THE RECIEVER COIL WHICH SENSES THE FIELD AS IT
COMES BACK IN THROUGH THE TUBE WALL.
8RFT is the inspection of ferromagnetic material
such as
- SA-214 CARBON STEEL (Welded)
- SA-179 CARBON STEEL (Seamless)
- SA-213 SA-199-T1 T11 (Chrome-Molly material)
- SA-178 (Boiler Tubes)
- SA-789 (2205 Duplex)
- SA-268 (EBRITE)
- Any other materials with magnetic domains.
9REMOTE FIELD TESTING (RFT) PRINCIPLE
Receivers
Direct field
Exciter
ILLUSTRATION OF SINGLE EXCITER / SINGLE PICKUP
10PROBE TYPES SINGLE EXCITER / SINGLE PICKUP
11COMMONLY USED PROBE DUAL EXCITER / SINGLE PICKUP
12TYPICAL REMOTE FIELD CALIBRATION(MULTI-PURPOSE
STANDARD)
13RFT GRAPHICS OF WASTAGE SMALL PITTING
14LINEAR ISOLATED PITTING
15LINEAR I.D. PITTING
16RFT SENSITIVITY TO SMALLER INDICATIONS THAT HAVE
LOWER PERMEABILITY
17DETECTION OF MIC IN 2205 DUPLEX / USING RFT
18ADVANTAGES OF REMOTE FIELD TESTING
- Applies to any Ferrous material (Carbon Steel).
- Tubes require little cleaning prior to
inspection. - Inspect tubes with low fill-factor and still
maintain good sensitivity. - Data acquisition rate of 50 up to 70 tubes per/hr
(Depends on wall thickness and sample rate). - Good sensitivity to gradual wall loss, pitting,
vibration, and steam erosion and cracking - Capable of testing heavy wall tubes (Up to .180)
- Capable of inspecting up to 3 inch diameter tubes
(Larger diameters w/special probe designs). - Repeatability Compare historical test results
to establish corrosion rates and remaining life
calculations.
19DISADVANTAGES OF REMOTE FIELD TESTING
- Limited detection and sizing of small defects
(lt1/8 Dia. depending on material type). - Permeability and geometry will affect sensitivity
to small defects and sizing. - Not sensitive to small cracks and pitting
(w/special probe designs such as Array Coils are
becoming alternative methods for detection). - Cannot distinguish between I.D. or O.D. defect
orientation (Historical information or service
would assist in narrowing down orientation of
defects). - Has difficulty in detection of lt20 wall loss
under baffle or support structures (Signal is
suppressed by structures). - Pull speed is dependent on frequency, sample
rate, and defect type. - Accuracy of interpretation is highly dependant
upon operator experience. - Equipment is both sophisticated and expensive.
20- IRIS
- (INTERNAL ROTATING INSPECTION SYSTEM)
I.D.
I.D.
O.D.
21IRIS INSPECTION PRINCIPLE
- This technique uses unique water driven rotating
mirror to direct an ultrasonic beam, which is
reflected 90 degrees to the internal tube wall.
The water acts as a water couplant and transmit
sound waves from the ultrasonic transducer to the
tube wall. - The IRIS presentation can be displayed in a
B-scan (Cross-sectional view) or C-scan showing
the tube wall thickness and isolated corrosion
areas along the tube length. - This technique used to inspect all tube material
types, (ferromagnetic and nonferromagnetic) in
diameters ranging from 5/8 up to 3 inch large
diameter boiler tubes (Large tubes or pipes have
been inspected with special probe designs). - IRIS accuracy is operator dependant, measurements
can be within or - 0.005 if tube conditions
are good.
22BOILER TUBE O.D. EROSION CORROSION (APPROX. 270
Deg.)
IRIS COMPUTERIZE COLOR B-SCAN C-SCAN DISPLAY
23BOILER TUBES O.D. EROSION/CORROSION
24IRIS SCAN OF RFT MULTI-PURPOSE STANDARD
25RFT IRIS comparison of 50 degradation (SA-214
.750 x .083)
26INTERMITTING AREAS OF DATA
27I.D. SCALE AND DEPOSITS / DIFFICULTIES OF IRIS
TESTING
28ADVANTAGES OF IRIS INSPECTION
- Used to inspect any tube material type ferrous or
nonferrous. - Provides accurate remaining wall thickness,
(empirical data /- .005). - Can detect gradual wall loss, pitting, baffle
fretting, steam erosion, and impingement erosion
at tube sheet area. - Can distinguish between I.D. and O.D. defect
orientation. - Can be used as prove up to other test methods
such as RFT and MFL.
29DISADVANTAGES OF IRIS INSPECTION
- Cleanliness of the tubes is a major factor and
requires thorough tube cleaning (removal of all
scale, deposits, chemical residue and/or oil
residue prior to inspection. - Slow inspection speeds of 20 to 40 tubes per/hr.
- Requires flooding the tube with water for sound
coupling. - Can not detect cracks (Special probe design is
needed). - Limited to isolated pit detection and pit size
(diameter). - Instruments, probe cables, and head assembly is
expensive.
30MAGNETIC FLUX LEAKAGE (MFL)STEELTEST
31MFL INSPECTION PRINCIPLE
- Magnetic Flux Leakage inspection is based on the
magnetization of the part under inspection and
the detection of magnetic flux lines leakage
field from the discontinuity in the magnetized
area. - Coils are mounted near the magnets which will
detect variations in the magnetic flux field
created by the anomalies in the tube wall. - The MFL technique can differentiate between
internal and external damage (Coils are spaced
apart). - This technique relies upon the dynamic movement
of the coils through the magnetic field
(measuring the voltage across the coils) as its
being pulled through the tube at a constant speed
of 12 inches per/sec. - This application is used for the inspection of
ferromagnetic materials such as SA-214, SA-179,
SA-178, SA-213-T1, Thru T-11, and etc.
32MAGNETIC FLUX LEAKAGE PRINCIPLE
The A- coil has more windings for sensitivity to
sharp external defects. The B- coil has less
windings for sensitivity to sharp internal
defects. The Hall Effect sensor measures the
total magnetic flux in the tube wall and detects
general wastage and baffle fretting.
33TYPICAL MULTI-PURPOSE CALIBRATION STANDARD FOR MFL
34MFL CALIBRATION / VOLTAGE AMPLITUDE BASED
35MFL OF AIR COOLER (FIN FAN) / ISOLATED O.D.
CORROSION
36MFL OF AIR COOLER (FIN FAN) / ISOLATED I.D.
CORROSION.
37MFL OF AIR COOLER (FIN FAN) / DISTORTION MAKES
IT DIFFICULT TO IRIS TEST
38MFL OF AIR COOLER (FIN FAN) / ANALYSIS BECOMES
COMPLEX
39ADVANTAGES OF MAGNETIC FLUX LEAKAGE (SteelTest)
- Applies to any ferromagnetic tubing (Carbon
Steel). - Tubes require little cleaning for inspection.
- High examination rate (Approx. 40-60 Tubes
per/hr.) - Has high sensitivity detecting wall loss at
baffle or support structures caused by fretting
or vibration. - Sensitivity to gradual wall loss and steam
erosion. - Can inspect up to 2 diameter tubes (larger with
special probe designs). - Can differentiate between I.D. and O.D. defect
orientation.
40DISADVANTAGES OF MAGNETIC FLUX LEAKAGE (SteelTest)
- Limited detection and sizing of small defects
(lt3/16 dia.). - Permeability and geometry will affect sensitivity
to small defects and sizing. - Not sensitive to small cracks and pitting
(w/special probe design such as Array Coils). - Pull speed will affect analysis if not consistent
(Permanent Magnets within the probe make it
difficult to maintain a steady pull speed for
analysis purposes). - Limited to minimum 20 wall loss.
- Threshold for accurately sizing defects is
approximately 50 depth. - Accuracy of interpretation is highly dependant
upon operator experience. - Equipment is sophisticated requires special
probes and instrumentation.
41EMERGING TECHNOLOGY
- REMOTE FIELD TESTING
- ARRAY COIL TECHNOLOGY
42RFT ARRAY COIL TECHNOLOGY
Bobbin probe Array probe
43RFT ARRAY COIL DISPLAY 100 TWH (Determines size
or extent of Defect)
44ADVANTAGES OF RFT ARRAY COIL
- Applies to any Ferrous material (Carbon Steel).
- Good sensitivity to gradual wall loss, pitting,
vibration, and steam erosion and cracking. - Capable to determine extent of corrosion for
sizing. - Capable of inspecting up to 3 inch diameter tubes
(Larger diameters w/special probe designs). - Repeatability Compare historical test results
to establish corrosion rates and remaining life
calculations.
45DISADVANTAGES OF RFT ARRAY COIL
- Limited detection and sizing of small defects
(lt1/8 Dia. depending on material type). - Permeability and geometry will affect sensitivity
to small defects and sizing. - Probe must maintain good fill-factor (Centered)
for sensitivity for detection of small defects. - Cannot distinguish between I.D. or O.D. defect
orientation (Historical information or service
would assist in narrowing down orientation of
defects). - Pull speed is dependent on frequency, sample
rate, and defect type. - Accuracy of interpretation is highly dependant
upon operator experience. - Requires special software and equipment to
operate. - Equipment is both sophisticated and expensive.
46X-RFT NEW EMERGING TECHNOLOGY
- X-RFT
- (EXTERNAL REFERENCE- REMOTE FIELD TESTING)
47X-RFT NEW EMERGING TECHNOLOGY DESIGN FOR AIR
COOLERS
- DEFINITION
- External Reference Remote Field Testing (X-RFT)
is an electromagnetic technique using the Remote
Field Technology connected with an external
reference to elimate extraneous noise by having a
balanced system. - The X-RFT is used primarily for the inspection of
air cooler tube inspection. - This method utilizes a 2nd probe placed in a
reference standard or tube of similar material
and dimensions of that to be inspected. This
enables the system to mix out any unwanted noise
to determine the defects depth. - The data is digitally collected and stored for
analysis. - The purpose of this application is to detect I.D.
inlet erosion/corrosion as well as isolated
pitting, channeling, and etc.
48X-RFT NEW EMERGING TECHNOLOGY
Similar to standard RFT probe except the coils
and sensors are much closer together to only
pick up the near-field portion of the induced
field.
49X-RFT ILLUSTRATION
50X-RFT AIR COOLER INSPECTION / EROSION/CORROSION
UP TO FERRULE
51X-RFT (DISCOVERY OF TEST RESULTS)
52X-RFT (Example of general wall loss from ferrule
end)
53X-RFT (DISCOVERY OF TEST RESULTS)
54X-RFT (Example of 50 degradation from ferrule
end)
55ADVANTAGES OF X-RFT
- Good sizing capabilities for Inlet Erosion
Corrosion. - Detects small diameter pitting.
- High data acquisition rate, (50 60 tubes/hr)
- Detects gradual wall thinning (I.D.)
- Capable of inspecting 3 diameter tubes, (larger
w/special probe designs)
56DISADVANTAGES OF X-RFT
- Limited O.D. sensitivity defect must be 50
through-wall before detection - Volumetrically dependant less sensitive to pits
under 1/8 diameter. - Permeability and geometry will affect sensitivity
to small defects and sizing. - Probe must maintain good fill-factor (Centered)
for sensitivity for detection of small defects. - Accuracy of interpretation is highly dependant
upon operator experience. - Equipment is both sophisticated and expensive.
57Procedures, Certification and Training
- Reference Documents being used are as follows
- ASNT SNT-TC-1A (Recommended Practice for
Nondestructive Testing of Personnel Qualification
and Certification) - ASTM E-543 (Practice for Agencies Performing
Nondestructive Testing). - ASTM E-1316 (Terminology for Nondestructive
Examination) - ASTM E 2096-05 (Standard Practice for In Situ
Examination of Ferromagnetic Heat Exchanger Tubes
Using Remote Field Testing) - It takes years of training for a tube inspector
to learn and demonstrate his/her ability to
perform a specific application consistently
accurate. - Example An individual can be trained to take
thickness readings within a short amount of time.
However, for tube inspection it takes repetitive
evaluation and observing changing conditions to
develop an understanding of the various process
corrosion, mechanical, and manufacturing failures
that occur on a day-to-day basis. - Certification in a particular test method does
not necessarily qualify that individual to
perform the inspection. - Qualifications and standards such as Mock-up test
bundles are being generated throughout the
industry to pre-qualify personnel, prior to
performing work in there plant.
58MOCKUP TEST QUALIFICATION BUNDLES
59MOCKUP TEST QUALIFICATION BUNDLES
60MOCKUP TEST QUALIFICATION BUNDLES
61CONCLUSION
- Some of these methods provide qualitative data
and some quantitative results - Each of these different methods have distinctive
advantages and disadvantages - It is imperative to choose the correct tube
inspection technique for the job at hand - Also, it has been proven that a combination of
methods can provide the best inspection results - Like most advanced inspection techniques, the
techniques are operator dependent, and it is
important to evaluate your inspection provider to
assure they are qualified and experienced
personnel
62DIVERSITY IS A MUST!
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