Fabrication of Tantalum Lined Piping

Fabrication of Tantalum
Lined Piping
Pete Philippon, P.E.
Director, Project Management / Technical Sales
Dennis Lamberth - Sales Manager
EXPERIENCE MATTERS
Tantalum and its properties
Unique Properties
•  Corrosion resistance
•  Comparable to glass and platinum
•  Inert at temperatures under 1500 C
–  Hydrochloric Acid (all concentrations)
–  Nitric Acid (all concentrations)
–  Up to 98% Sulfuric Acid
–  Up to 95% Phosphoric Acid
•  Pharmaceutical and other batch processes
Increading Chloride Conc.
Oxidizing Environment - Incr. Strength
Reducing Environminet - Incr. Strength
Acid Chloride
Tantalum
Impervious Graphite
Zirconium
Ni-Mo Alloys, “B” Alloys
Niobium
Titanium + Nobel Metals
Titanium
Ni-Cr-Mo Alloy, “C” Alloys
Monel
No Chlorides
Zirconium
No. 20 Alloy (Stainless)
Monel
Inconel
316 Stainless
304 Stainless
Oxidizing Acids
Increasing Aggressiveness
Reducing Acids
Mechanical Properties
•  UNS R05252
–  97.5% Tantalum
–  2.5% Tungsten
•  Yield strength – 30,000 psi
•  Density – 0.600 lb/inch3
•  Thermal Conductivity - 36 Btu/hr-ftoF
–  (3x Titanium)
•  Coefficient of Thermal Expansion
–  6.6x10-6 in/in0F
Comparison
Matl.
Density
lb/in3
Price
Per
pound
Price per
Sq Ft
¼ thick
Ratio
304 SS
0.291
3
31
1.0
316 SS
0.291
4
42
1.4
Ti-Gr 2
0.163
13
76
2.5
Ti-Gr 7
0.163
35
205
6.6
C-276
0.321
26
300
9.7
Zr-702
0.234
37
312
10.0
Ta 2.5%
0.600
500
10,800
348.4
Design of lined piping
•  Convolutions / Ribbing for vacuum
•  Stay bolts
Design of Lined Piping
•  Liners are typically 0.015 – 0.020 thick
•  Internal pressure taken up by the outer pipe, which is the
pressure boundary
•  Liners are made with specific clearances to allow the
liner to expand into the pipe during hydro
–  Small diameter 1/16
–  Large diameter up to 1/8
•  Tantalum is fairly ductile material
•  Tantalum is a non-ASME code material
External Vacuum Pressure
•  Design for vacuum per ASME or other
applicable codes
•  Design for maximum unstiffened length for
the desired thickness
•  Add stiffening moments of inertia
(convolutions) as required.
3,704
Stay Bolts
•  Used for vacuum on flat surfaces such as
covers
•  Use when ribbing alone is not sufficient for
the vacuum service
•  Caution
–  Stay bolts can result in a high stress area and
a failure/leak path
332,598
Stay Bolts Con t
•  Proper design is critical
•  Consider other options
–  Explosion cladding
–  Other cladding
–  Glass lining
–  Teflon® lining
–  Sacrificial lower cost covers (example C-276)
Fabrication
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Cleaning
Convolutions / Ribbing
Tooling
Fitting
Welding
Purging
Platinum spots
Cleaning
•  Edges filed to remove any foreign deposits left
from cutting
•  Clean weld zone 1-2 back with Scotchbrite®
(3M)
•  Wipe with a residue free cleaning solvent, such
as MEK or Acetone using lint free white cotton
rags
•  Handle only with clean and oil free gloves
Convolutions / Ribbing
•  Shape designed for required moment of
inertia
•  Special tooling required (convolutions)
•  Formed incrementally
–  Typically 3 settings
Tooling
•  Custom designed for convolutions / ribbing
configuration and thickness
•  Preferably, the tools used for fitting should
be fitted with tantalum covers
•  If not practical, then hardened steel,
stainless steel or aluminum bronze (non
ferrous)
Fitting
•  Tack weld in a controlled atmosphere
•  Standing edges are preferred for welding
•  In some cases, the pipe and or fitting may
need to be split to allow for insertion of
tantalum liner
Welding
•  Tig welding (GTAW) with Argon as a
purge or shielding gas
•  99.9% purity
Purging
•  Use 2 purge holes on each pipe end,
including branches (1/4 NPT)
•  Pipe over 10 long
–  Use 2 additional purge holes in the center
Platinum Spots
•  For applications in which hydrogen embrittlement is a
concern
•  Clean area before application with cleaning solvent
•  Apply insulating tape/template with correct hole size
required
•  Spot blast with aluminum oxide media
•  Dust off media with a quick blast of compressed air
•  Apply solution 50gm/liter platinum
Testing
•  Air & Soap
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To check between liner and shell
Low pressure
Use purge holes to pressurize
No defects
•  Dye Check
–  Conventional red dye
•  Vacuum – check for failure
•  Helium leak
–  Draw a vacuum between liner & steel through purge holes
–  At or below 100 micron sensitivity
•  Hydrostatic Testing
Hydrostatic Testing
•  1.3 X design pressure
•  Bring unit up slowly to allow expansion of liner
•  When test pressure is reached, it may drop until
liner is seated against containment shell
•  The hydrotest test pressure can then be
maintained
Questions – Comments
On behalf of Tricor, I want to thank you for the
opportunity to be here.
Pete Philippon, P.E. - Tricor Metals
Wooster, Ohio / Conroe, Texas
Cost Effective Corrosion Solutions Through Design and Engineering
EXPERIENCE MATTERS