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

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

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)

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

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

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

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)

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)

Titanium Corrosion Resistance Wide range of passivation

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

Titanium & Titanium Alloys for the CPI Market

Mechanical Properties Titanium alloys Mechanical Properties High Medium Low

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

Titanium alloys-Reducing acids

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

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

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

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

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

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

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

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

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

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

Galvanic series-Sea water

Ti application Sea water application Centrifugal pumps

Ti application Sea water application Cast pump for handling sea water

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

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)

Benefits-Design Allowance

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

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

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

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