TFC KAOHSIUNG FACTORY 30 KMT AMMONIA ... TAAIA[3].pdfT-101 is a flat bed, double wall & double roof...
Transcript of TFC KAOHSIUNG FACTORY 30 KMT AMMONIA ... TAAIA[3].pdfT-101 is a flat bed, double wall & double roof...
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TFC KAOHSIUNG FACTORY 30
KMT AMMONIA STORAGE TANK
INSPECTION REPORT
By: Jackson Yang (TFC R&D Department)
01 Oct 2016
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CONTENT
1. Introduction
2. Internal Inspection Planning
3. Applied Inspection Technique
4. Inspection Findings 1) External & internal visual inspection
2) Bottom plates corrosion test & UT measurement
3) Bottom plates weld WFMP test
4) Bottom plates & shell plates joint weld WFMP test
5) Shell plates weld WFMP test
6) Accessories weld WFMP test
7) Mechanical properties test
5. Summary
T-101 is a flat bed, double wall & double roof anhydrous liquid
ammonia storage tank. The internal wall is constructed with low
temperature resistant steel plate and outer wall is constructed by
steel covered with reinforced concrete wall. Inside of external wall
has 6m/m layer of low temperature resistant steel and a layer of
insulation cotton.
The internal tank dimension is 48 meter diameter and 38 meter
height with 60,000 cubic meter volume. The design storage
capacity is 30,000 MT anhydrous liquid ammonia.
All the tank nozzles and transfer pump connections are located at
the tank roof, there is no any nozzle connection at the side or
bottom of the tank.
The tank was designed and constructed in 1987 by Mitsubishi
Heavy Industries & Chiyoda Tank Engineering Corporation,
Japan. For 27 years (1987-2014), this tank was well maintained
and successfully operated without incurring any incident related to
safety or environmental issues.
Description of Ammonia Storage
Tank T-101
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Inspection Planning
1. Inspection Party: Taiwan Metal Quality Control Co., LTD
(TMQC)
2. Inspection Date: Inspectors got entry permit to start T-101
internal inspection on 7 Jun 2016. The field inspection,
testing & data collecting were completed on 17 Jun 2016.
3. Inspection Program: Refer to the inspection methodology
& scope in the next slides.
T-101 Inspection Program-1
Inspection area Technique Description 1. Tank internal and
external structure
Visual Inspection Visual inspecting bottom plates, wall plates, ceiling
plates, fittings, nozzles for any deformation, bulging,
dents, corrosion, cracking and localized corrosion.
Keep the photographic record.
2a. Corrosion test of
bottom plates on both
soil side & chemical
side
Floor Mapping test
(Magnetic Flux
Leakage test,
MFL)
Apply Floor Mapping to test all bottom plates for any
corrosion on both soil side & chemical side. Against the
corrosion parts, apply Ultrasonic thickness test to
measure the plate thickness.
2b. Corrosion test of
Annual Ring Plate on
both soil side &
chemical side
Hand Type Floor
Mapping test
Apply Hand Type Floor Mapping to test annular ring
plates and the area that Floor Mapping cannot reach.
Against the abnormal parts, apply Ultrasonic thickness
test to measure the plate thickness.
2c. bottom plates
ultrasonic thickness
measurement
Ultrasonic
thickness
monitoring (UT)
Take 6 samples of each selected plate ( 30 cm from 4
corners and 2 at center region) to do UT measurement
for observing corrosion rate and trend.
2d. bottom plates
welds
Wet fluorescent
magnetic particle
test (WFMP)
Bottom plates are the most loaded and stressed area.
Apply WFMP test to samples of 30 cm from left & right
each for all T and Y welds.
3. Bottom and wall
joint welds
Wet fluorescent
magnetic particle
test (WFMP)
To do WFMP test for 100% bottom and wall joint welds.
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T-101 Inspection Program-2
Inspection area Technique Description 4. Shell plates welds Wet fluorescent
magnetic particle
test (WFMP)
1. Apply WFMP to vertical welds (50 cm above bottom
plate) in course 1.
2. Apply WFMP to 100% horizontal and vertical welds
in course 1 and 2 (50 cm left & right and 50 cm up &
down).
4a Shell plates thickness
measurement
Ultrasonic
thickness
monitoring (UT)
Take 6 samples of each shell plate from course 1 & 2
(30 cm from 4 corners and 2 at center region) to do UT
measurement.
5. Accessories welds Wet fluorescent
magnetic particle
test (WFMP)
1. Apply WFMP to all manhole welds and fitting welds.
2. Apply WFMP to pump seat casing welds.
3. Apply UT to 2 samples of pump seat casing plates.
6. Pseudo installation
welds
Wet fluorescent
magnetic particle
test (WFMP)
Apply WFMP to 10% samples.
7. Against crack or
corrosion on welds
ultrasonic
phased-array
detector test
When observing weld cracks or corrosion, apply
advanced ultrasonic phased-array detector for further 3-
D imaging detection.
8. Mechanical
properties test
1. Take 2 samples each of bottom plates from center,
half radius and near wall to do pull test.
2. Take 2 samples each of wall plates from course 1 & 2
to do pull test. . 12
Applied Inspection Technique
Technique Inspection Area Remarks
Visual Testing Tank bottom/shell/roof View deformation, bulging,
dents, corrosion, cracking,
localized corrosion.
Magnetic Flux
Leakage test
(MFL)
Tank bottom plates/Annual Ring Plate Corrosion test of bottom plates
on both soil side & chemical
side
Ultrasonic
gauging (UT)
Bottom/shell plate (including vapor-
liquid phase interface)/roof
Measure steel plates thickness
Wet Fluorescent
Magnetic
Particle Testing
(WFMP)
(A) the base plate bead comprising an
annular plate, (B) the bottom wall
bead, (C) wall weld: horizontal and
vertical bead, (D) the top wall groove
weld, (E ) tank top bead, (F) on the
tank nozzle (or cannula) bead
Inspect orientation: Vertical &
horizontal bead, wall covering
at least a gas and liquid phase
region.
Refer to the next slide for
sampling location.
Mechanical
Properties
Testing
Sampling: chassis / shell plate / roof of
the weld and the base material, each
three pieces
Test items:
(A) Tensile test: room temp.
(B) Impact test: -33 ℃
(C) Hardness test: room temp.
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Scope of Internal Inspection
Step 1: Initial inspection
Step 2: The 2nd inspection if any defect found during initial inspection.
Step 3: The 3rd inspection if any defect found during the 2nd inspection.
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1A: External visual inspection
findings • Tank external ladder was corroded at some parts and tank
top platform and handrail were found corroded and deformed.
Roof platform corroded Roof handrail corroded
and deformed
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1B: Internal visual inspection findings
• During visual inspection, found 2 bolts of internal pipe
flange connection were missing and an impact dent of 1.5
mm depth at bottom plate. No other abnormality was
observed at internal tank.
2 bolts missing Impact dent (A16)
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2A: Bottom plates corrosion test and UT
measurement
• Applied UT to measure the corrosion rate. The design
bottom edge plate thickness was 19.0 mm, UT test result
was 19.2~19.6 mm, no soil side corrosion found. The
design other bottom plate thickness was 4.8 mm, UT test
result was 4.9~5.2 mm, no soil side corrosion found.
Bottom plates MFL test
Bottom plates UT
measurement
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2B: Bottom plates corrosion test and UT
measurement
Impact dent (A1)
Bottom plates numbering (A1~A139)
• The bottom plates were numbered from A1to A139.
• Applied MFL(Magnetic Flux Leakage test) to do floor mapping,
found 6 defects. After visual confirmation, 1 defect at ring plate
was impact dent (A1) and the other 5 defects were chemical
side corrosion.
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2C: Bottom plates corrosion test and UT
measurement
• Applied MFL to do floor mapping, found 6 defects. After visual
confirmation, 1 defect at ring plate was impact dent and the other 5
defects were chemical side corrosion (A20*2/A22/A30/A68).
corrosion defect (A68)
corrosion defect (A20)
corrosion defect (A30)
corrosion defect (A22)
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3: Bottom plates T & Y welds WFMP test
• For T & Y welds of bottom plates, applied WFMP test at 30
cm left and right areas. No crack at first or second layer
was found.
Bottom plates T welds WFMP test Bottom plates Y welds WFMP test
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4: Bottom and shell plates joint welds
WFMP test
• The joint welds of bottom and shell plates are the most
loaded and stressed area, applied WFMP to do 100% test,
no crack at first or second layer was found.
Bottom & shell plates joint
welds WFMP test Bottom & shell plates joint
welds WFMP test
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5A: Shell plates welds WFMP test and UT
measurement
• Apply WFMP to vertical welds at 50 cm above bottom plate
in course 1 and horizontal and vertical welds in course 1
and 2 at 50 cm left & right and 50 cm up & down for 100%
test. No crack at first or second layer was found.
Shell plates welds WFMP test Shell plates welds WFMP test
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5B: Shell plates welds WFMP test and UT
measurement
• Take 6 samples for each shell plate from course 1 & 2 (30 cm from
4 corners and 2 at center region) to do UT measurement. The
design plate thickness of course 1 was 30.3 mm, the UT test result
was 29.9~30.2 mm, no shell plate corrosion in course 1 found. The
design plate thickness of course 2 was 27.4 mm, the UT test result
was 27.2 mm, no shell plate corrosion in course 2 found.
Shell plates
numbering (S1 & S2)
Shell plates UT measurement
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6: Accessories welds WFMP test
• Apply WFMP to 2 sets of manhole welds and submerged
transfer pump fitting welds. No crack at first or second
layer was found.
Northern manhole
WFMP test Southern manhole
WFMP test
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7: Mechanical properties test
• The sample tank plate pieces were subjected to three
kinds of mechanical properties tests: the tensile test,
positive bending & back bending test, low temperature
impact test.
Photo of sample tank plate test pieces
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7A: The tensile test result:
• Compared with the ASTM standard values, all test pieces are in line
with the standard, only No. 8 bottom plate yield strength less than
the standard value 1N /mm2. Observed 3 groups of test pieces, the
fracture points are also fall in the base metal, showing the bead
strength is higher than the base metal required strength.
S# Test Pieces Description Cross
area
(mm2)
Ultimate
strength
(N/mm2)
Yield
strength
(N/mm2)
Elongation
% (G.L=
200mm)
Fracture
point
STD ASTM A537-CL1 - 485-620 345 18 -
No.1 Sidewall bead test piece 1S-12 578.3 603 - - Base metal
No.2 Sidewall bead test piece 2S-10 519.7 595 - - Base metal
No.3 Outer ring plate bead A11 353.4 586 - - Base metal
No.4 Sidewall metal test piece 1S-12 154.7 552 464 33 -
No.5 Outer ring plate metal A11 153.0 536 450 32 -
No.6 Sidewall metal test piece 2S-10 152.8 560 448 32 -
No.7 Bottom plate metal A76 224.0 525 366 23 -
No.8 Bottom plate metal A81 220.0 526 344 20 -
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7B: Positive & back bending test result:
• The presence of crack of No.4 ~ No.8 test pieces in the
positive bending and back bending test are not found,
indicating that the material anti-bending ability is still quite
adequate after 29 years of use.
S# Test Pieces Description Positive
bending test
Back
bending test
No.4 Sidewall metal test piece 1S-12 No crack No crack
No.5 Outer ring plate metal A11 No crack No crack
No.6 Sidewall metal test piece 2S-10 No crack No crack
No.7 Bottom plate metal A76 No crack No crack
No.8 Bottom plate metal A81 No crack No crack
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7C: Low temperature impact test result:
• No.4 to 6 test pieces were made to a V-notch of 10x10x55 size. The
three test pieces had high absorption energy of 260J, 112J &182J.
It indicates that the side wall and bottom plates in the low-
temperature area still has a very good toughness, did not change
into brittle material and still meet the standard requirements after
long-term service.
S# Test Pieces Description V-notch
(mm)
Test Temp.
(oC)
Absorption
Energy (J)
No.4 Sidewall metal test piece
1S-12
10*10*55 -35 260
No.5 Outer ring plate metal
A11
10*10*55 -35 112
No.6 Sidewall metal test piece
2S-10
10*10*55 -35 182
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T-101 Inspection report summary
• The UT measurement had been done for T-101 shell
plates in course 1 & 2 (S1 & S2) and bottom plates:
The design and actual thickness difference for shell
plates S1 is 0.1~0.4 mm and for S2 is 0.1~0.3 mm.
The bottom plates thickness measurement showing
the actual is higher than design value.
• T-101 was operating in the condition of -33 oC and there
was no corrosion mechanism available. Therefore, it is
reasonable to conclude that the thickness difference
between design and actual is resulting from
manufacturing tolerances of the plates during
construction.
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T-101 corrosion rate & remaining life
assessment
• Based on thickness measurement data, the corrosion rate
and the tank remaining life are calculated:
T-101 corrosion rate is 0.0034-0.0138mm/year.
T-101 remaining life is 43.5 years at minimum.
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Conclusion of T-101 inspection report
• The factors that will affect the integrity of ammonia storage
tank are: construction defect, corrosion, SCC crack and fatigue.
Taking the opportunity of T-101 decommission, this ammonia
storage tank had gone through thorough internal inspection by
non-destructive technique.
• There is only minor corrosion spots observed on bottom plates
and no defect found on all shell plates and welds. All welds
were inspected without SCC cracking as observed. Based on
this inspection result, we can conclude that ammonia storage
tank under cryogenic operating condition, there is no sign of
corrosion or SCC crack/fatigue even after near 30 years of
service.
• Therefore, it is concluded that if we are able to strictly control
the construction quality, eliminate construction defects, follow
proper commission procedure and normal operating procedure,
the risk of tank failure can be considered as zero.