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

2. 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

3. 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)

4. Typical CPI Power Generation Petrochemical Organic acid Chemical
Fertilizers
Metal Recovery
Salt
Chlorine
Pulp & paper

5. CPI Equipment Heat Exchangers Reactor vessels Piping Pumps Mixers
Anodes
Anode baskets
Distillation Columns

6. 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

7. 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)

8. Titanium Corrosion Resistance
Anodic Protection (external power supply)
Inhibitors (Fe+3, Cu+2, Mo+6,etc..)
Alloying with stable elements (Mo,Zr ,Cr)
Alloying with noble metals (Pt,Pd,Ru)
Very resistant to oxidizing media (HNO3)

9. Titanium Corrosion Resistance
Wide range of
passivation

10. 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

11. Titanium & Titanium Alloys for the CPI Market

12. Mechanical Properties
Titanium alloys
Mechanical Properties
High
Medium
Low

13. 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

14. Titanium alloys-Reducing acids

15. Crevice corrosion possible
Localized Corrosion
Crevice corrosion possible
Grades 1, 2, & 3
Pd Grades 7 & 16
Grade 12
14 -
7 -
0 - pH
150
300
General Guidelines for Crevice Corrosion Resistance of Titanium in NaCl Brine Media
Temperature (ºC)
Not susceptible to pitting or SCC attack (unalloyed grades)
All Ti grades resistant to crevice attack to about 80°C
Other grades (especially Pd) can be used up to >250°C

16. Corrosion - Galvanic Effects
Ti very noble in chlorides - almost always the 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 > 80ºC

17. Shell, Chevron, BP (AMOCO)
CPI companies use Ti
Dow,Dupont
Shell, Chevron, BP (AMOCO)
Morton Salt
Kerr-McGee
Bayer
Heinz
BASF

18. Ti lined reactor vessel for mining operation
Ti application in CPI
Reactor Vessel
Ti lined reactor vessel for mining operation

19. Ti application in CPI cont..
Tube Exchanger
Straight heat tube exchanger

20. Ti application in CPI cont..
Tube Exchanger
Plate coil immersion heat exchanger
Plate heat exchanger

21. Ti application in CPI cont..
Ti tubed salt evaporator for table salt

22. Ti application in CPI cont..
Ti anode baskets for anodized metal parts

23. Benefits-Corrosion Resistance
(Sea Water)
Corrosion Mode Cu
Alloys Al
316 SS
Adv. Ni
Titanium
General Corrosion
R/S R
Erosion Corrosion S
Pitting Attack
Crevice Corrosion
Stress Corrosion
MIC
Weld Attack
Galvanic Attack
Composite Comp.
S=Susceptible
R=Resistance

24. 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

25. Galvanic series-Sea water

26. Ti application
Sea water application
Centrifugal pumps

27. Ti application
Sea water application
Cast pump for handling sea water

28. 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

29. 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)

30. Benefits-Design Allowance

31. 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

32. >30 yrs service history
Ti role in the CPI
>30 yrs service history
Mature Applications

33. <20 yrs service history
Ti role in the CPI
<20 yrs service history
Newer Applications

34. 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
>40 years proven service in the CPI