Titanium in Chemical Process Industry

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Titanium in Chemical Process Industry (CPI)
Suresh Divi Corrosion Engineer Titanium Metals
Corporation (TIMET)
Process Corrosion Session NACE Eastern Area
Conference Oct. 7, 2009
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Outline

• Introduction to the CPI
• CPI Equipment/Components
• Titanium Corrosion Resistance
• Titanium alloys
• Ti Applications in CPI
• Benefits Cost considerations
• Ti role in the CPI
• Summary

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Introduction to the CPI

• An industry in which the raw materials undergo
  chemical conversion during their processing into
  finished products
• Chemical conversion influences the pH of the
  product
• Intern pH influences the corrosion resistance of
  the metal
• Very aggressive conditions (low pH, high
  temperature)
• In Petroleum refining, acidic conditions arise
  from chloride salts entering the refinery in
  crude oil
• Dilute HCl acid encounter in many chlorination
  type chemical process.Example Manufacturing of
  Vinyl chloride monomer(VCM)

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Typical CPI

• Power Generation
• Petrochemical
• Organic acid
• Chemical
• Fertilizers
• Metal Recovery
• Salt
• Chlorine
• Pulp paper

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CPI Equipment

• Heat Exchangers
• Reactor vessels
• Piping
• Pumps
• Mixers
• Anodes
• Anode baskets
• Distillation Columns

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Titanium

• Abundant - Not Exotic!
• 4th most plentiful metal on earth
• Classified as a reactive metal (passive oxide
  film)
• About half as dense as nickel
• Similar in strength to 316 S.S. (CP Ti)
• Excellent corrosion resistance/immunity in
  chlorides (especially sea water)
• 45 years service experience with the CPI

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Ti Corrosion Resistance

• Corrosion protection is due to the formation of
  oxide film
• Thin (100Å) and transparent
• Stable and chemically resistant
• Smooth and ceramic like, hard to remove
• Instantaneously reheal after damage
• (needs traces of water or oxygen)

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Titanium Corrosion Resistance

• Anodic Protection (external power supply)
• Inhibitors (Fe3, Cu2, Mo6,etc..)
• Alloying with stable elements (Mo,Zr ,Cr)
• Alloying with noble metals (Pt,Pd,Ru)
• Very resistant to oxidizing media (HNO3)

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Titanium Corrosion Resistance
Wide range of passivation
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Titanium Corrosion Resistance

• Excellent resistance to chloride corrosion
  (pitting)
• Immune to soil atmospheric corrosion
• No preferential weld corrosion
• Immune to MIC (microbial influenced
  corrosion)attack
• Good resistance to Erosion
• No corrosion in Sea water

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Titanium alloys
Titanium Titanium Alloys for the CPI Market
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Titanium alloys
Mechanical Properties
High
Medium
Low
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Titanium alloys

• Low Strength Grades (1, 2, 7, 11, 16, 17)
• Grade 2 most readily available
• Strength similar to austenitic SS
• Pd/Ru does not affect mechanical props

• Medium Strength Grades (3, 12, 9, 28)
• Can be cold formed (strip producible)
• Available in all product forms
• Strength similar to duplex SS
• Highest strength ASME grades

• High Strength Grades (23, 29, 32, 5)
• Common product forms are bar/billet/plate
• Must use heat when forming
• Weldability is best in grade 32
• Oxygen/Al content affect toughness and SCC

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Titanium alloys-Reducing acids
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Localized Corrosion

• Not susceptible to pitting or SCC attack
  (unalloyed grades)
• All Ti grades resistant to crevice attack to
  about 80C
• Other grades (especially Pd) can be used up to
  gt250C

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Corrosion - Galvanic Effects

• Ti very noble in chlorides - almost alwaysthe
  cathode
• Since Ti is cathode, no concern for corrosion
• In galvanic couple, other metal may have
  accelerated corrosion attack
• Hydrogen damage to Ti may occur if cathodic
  potential not regulated and if temperature gt 80ºC

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CPI companies use Ti

• Dow,Dupont
• Shell, Chevron, BP (AMOCO)
• Morton Salt
• Kerr-McGee
• Bayer
• Heinz
• BASF

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Ti application in CPI
Reactor Vessel
Ti lined reactor vessel for mining operation
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Ti application in CPI cont..
Tube Exchanger
Straight heat tube exchanger
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Ti application in CPI cont..
Tube Exchanger
Plate coil immersion heat exchanger
Plate heat exchanger
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Ti application in CPI cont..
Ti tubed salt evaporator for table salt
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Ti application in CPI cont..
Ti anode baskets for anodized metal parts
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Benefits-Corrosion Resistance (Sea Water)
Corrosion Mode Cu Alloys Al Alloys 316 SS Adv. SS Ni Alloys Titanium
General Corrosion R/S R R R R R
Erosion Corrosion S R R R R R
Pitting Attack S S S R R R
Crevice Corrosion S S S S S R
Stress Corrosion R/S S R/S R R R
MIC S S S S R R
Weld Attack S S S S R R
Galvanic Attack S S S R R R
Composite Comp. S S S S S R
RResistance
SSusceptible
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Benefits-Corrosion Resistance (Performance)
Maximum Performance Minimum Performance

• Titanium ASTM Grades 7 16
• Titanium ASTM Grade 12
• Titanium ASTM Grade 2 / Alloy C-276, C-22, 59
• Alloy 625
• 6 Mo Stainless Steel / 2507 Stainless Steel
• 2205 Stainless Steel
• 316L Stainless Steel
• 304 Stainless Steel

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Galvanic series-Sea water
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Ti application
Sea water application
Centrifugal pumps
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Ti application
Sea water application
Cast pump for handling sea water
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Benefits-Density

• Roughly half as dense as iron nickel based
  alloys
• A pound of titanium goes a lot further

Copper
Titanium
Zirconium
Stainless Steel
Nickel
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Benefits

• Good Thermal Conductivity (12.5 Btu/Hr-Ft2-F/ft)
• 30 above 300 series Stainless steel,
• 60 above the super stainless grades

• Low Elastic Modulus (15 Mpsi)
• Titanium flexibility considered into design and
  fabrication
• (supports,shafts)

• Life cycle
• Ti wins life cycle costing and proper design
  engineering
• (thin wall, no corrosion allowance)

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Benefits-Design Allowance
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Cost considerations

• Total system installed cost maintenance
• Eliminate multiple installation/replacement costs
• Reduced maintenance costs (oxide forms slick
  surface)
• Titanium does not require coatings
• Environmental/contamination costs (Ti non-toxic)
• Reuse/recycle of Titanium

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Mature Applications
Ti role in the CPI
gt30 yrs service history
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Newer Applications
Ti role in the CPI
lt20 yrs service history
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SUMMARY

• Excellent chloride corrosion resistance
• Wide selection of alloy properties without
  sacrificing corrosion resistance
• Proven resistance to many organic chemicals
• Environmentally friendly metal
• Cost effective for CPI equipment
• gt40 years proven service in the CPI