Titanium Erosion in Urea Strippers & Emerging Technologies
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Transcript of Titanium Erosion in Urea Strippers & Emerging Technologies
TITANIUM EROSION IN UREA STRIPPERS & EMERGING
TECHNOLOGIES
Fauji Fertilizer company Limited
Ali Abrar
Unit Manager InspectionAreas of expertise reliability, Integrity, Inspection
Titanium Urea Stripper
Urea Stripper Function
The urea stripper strips out vapors (In the form of Ammonia and Carbon dioxide) from the urea solution.
PRC-13V
MC
MS
STRIPPER
Solution in
Vapors out
Solution out
Steam in
Construction
Pressure Retaining shell Carbon steel
Corrosion resistant material Titanium
Tubes and inside clad material is Titanium
Internals 25CR-22Ni-2Mo
TUBE
FERRULE
Solution film formation inside tube
TUBE SHEET
Vapors stripping
TANGENTIAL HOLES
Erosion in Titanium Strippers
Erosion of cladding
Groove formation at ferrule end
Tube thickness reduction below top tube sheet
Solution inlet liner erosion
Cladding thickness loss
More area erodes against solution inlet
nozzleMaximum erosion rate expected =0.25 mm/yr
Repaired pits
Mock up
Erosion of tubes at top tube sheet
• Tube Edge Erosion (A)• Old Groove (B)• New Groove formation (C)• Thickness below new groove (D)• Thickness below top tube sheet (E)
Year min max Avg min max AvgGM 2003 3.07 3.97 3.56 - - -Donagani 2006 2.95 3.90 3.53 0 0.19 0.01
B Force 2005 2.51 3.38 2.89 0.05 0.63 0.33
C Donagani 2006 2.10 3.95 2.95 0 1.17 0.51
D Donagani 2006 2.75 3.75 3.17 0 0.24 0.13
Donagani 2003 2.42 3.96 3.40 0 0.33 0.10Force 2005 2.17 3.69 2.87 0 - 0.26Donagani 2006 2.15 3.95 2.91 0 0.45 0.16
a Avg 0.163b Max Value >2XAvg 0.327c Compensation 0.06/EC 0.120
Max Expected value (b+c) 0.447
B
C
D
Year min max Avg min max Avg
a Avg 0.163b Max Value >2XAvg 0.327c Compensation 0.06/EC 0.120
Max Expected value (b+c) 0.447
A
B
C
D
A
CD
E
B
Erosion of tubes at top tube sheet
Erosion of the tube is visible at the top edge and inside due to solution by passing
Grooves are visible inside the tubes
Cutaway section of a tube, groove is visible.
Erosion of tubes at top tube sheetB
C
R21T8 R21T6R21T7
EC signals of grooves.
EC thickness profile of a tube
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1011121314151617181920212223242526272829303132333435363738394041424344454647484950515253545556575859606162636465
E-101 TOP TUBE SHEET LAYOUT
Count FROM TO9 0 2.45
29 2.46 2.5103 2.51 2.6370 2.61 2.7676 2.71 2.8
1589 2.81 3.972776
EC data of tubes thickness
Tubes thickness reduction trends
Urea stripper refurbishment procedure
Urea stripper refurbishment activities
Urea stripper refurbishment activities
Installation of rehabilitated stripper
Experience of refurbished stripper
High rate of erosion at the end of ferrule adaptors in the tubes.
Old groove
New groove
Advancement of adaptor to cover
eroded part of the tubes
New Technology Development
Pure Zr and Ti-Zr tubes being installed in TA-2005
Extrusion bonded Titanium tube with Zirconium
Extrusion bonded Inertia welded tube
Condition of Zr & Ti-Zr and friction welded Tubes (after one year of operational testing)
Zr tube joined with Coaxial (Ti-Zr) tube with friction weld. The mockup was installed at the bottom
of stripper.
Two sample tubes were installed in TA-2005; Pure Zr and the other Co-axial Ti-
Zr tube. The results were found satisfactory in TA-2006. However there are reservations on quality of welds for pure Zr tubes in Titanium strippers for
new equipment.
Pure Zr tubeTi-Zr Coaxial tube