Titanium in Chemical Process Industry (CPI)

Suresh DiviCorrosion Engineer

Titanium Metals Corporation (TIMET)

Process Corrosion SessionNACE 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

•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)

Introduction to the “CPI”

•Power Generation

•Petrochemical

•Organic acid

•Chemical

•Fertilizers

•Metal Recovery

•Salt

•Chlorine

•Pulp & paper

Typical CPI

CPI Equipment

•Heat Exchangers

•Reactor vessels

•Piping

•Pumps

•Mixers

•Anodes

•Anode baskets

•Distillation Columns

• 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

Titanium

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 alloysTitanium & Titanium Alloys for the CPI Market

1 TIMETAL@ 35A Unalloyed Titanium R50250 Alpha 80-90C LowMost formable grade-for cladding & PHE

FEATURESNOMINALCOMPOSITION

TIMETDESIGNATION

ALLOYTYPE

UNSDESIG.

ASTMGRADE

CREVICE THRESHOLD

MECHSTR

1 TIMETAL@ 35A Unalloyed Titanium R50250 Alpha 80-90C LowMost formable grade-for cladding & PHE

2 TIMETAL@ 50A Unalloyed Titanium R50400 Alpha 80-90C LowMost widely used titanium grade-best comb. of props

7 16

TIMETAL@ 50A Pd TIMETAL@ 50A 05Pd

Ti-0.15Pd Ti-0.05Pd

R52400 R52402

Alpha >250C LowAdded corrosion resistance over grade 2

3 TIMETAL@ 65A Unalloyed Titanium R50550Lean

Alpha/Beta 80-90C Medium Added strength vs grade 2

FEATURESNOMINALCOMPOSITION

TIMETDESIGNATION

ALLOYTYPE

UNSDESIG.

ASTMGRADE

CREVICE THRESHOLD

MECHSTR

9 TIMETAL@ 3-2.5 Ti-3Al-2.5V R56320Lean

Alpha/Beta 80-90C MediumCold formable, med. strength titanium alloy

32 TIMETAL@ 5111Ti-5Al-1Sn-1Zr-1V-0.8Mo-0.1Si R55111

Lean Alpha/Beta 80C High

High toughness/weldable alloy for plate/fasteners

5 TIMETAL@ 6-4 Ti-6Al-4V R56400 Alpha/Beta 80C HighStd. aero alloy-some SCC concerns in sea water

23 TIMETAL@ 6-4 ELI Ti-6Al-4V-0.1O R56407 Alpha/Beta 80C HighLow oxygen grade 5-no SCC but lower strength

FEATURES

3 TIMETAL@ 65A Unalloyed Titanium R50550Lean

Alpha/Beta 80-90C Medium Added strength vs grade 2

12 TIMETAL@ CODE 12 Ti-0.3Mo-0.8Ni R53400Lean

Alpha/Beta ~150C MediumAdded corrosion resistance & strength vs grade 2

9 TIMETAL@ 3-2.5 Ti-3Al-2.5V R56320Lean

Alpha/Beta 80-90C MediumCold formable, med. strength titanium alloy

FEATURES

Titanium alloys

0

20

40

60

80

100

120

140

160

180

Ty

pic

al P

rop

ert

ies

(k

si o

r %

)

Tensile

Yield

Elongation

415

550

690

825

965

1100

1240

275

138

0

Typ

ica

l Str

en

gth

(M

Pa

)

1 233291232 5

ASTM Titanium Grade

Mechanical Properties

Low

Medium

High

Titanium alloysLow 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 gradesHigh 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

• 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

Localized Corrosion

Crevice corrosion possible

Grades 1, 2, & 3

Pd Grades 7 & 16

Grade 12

14 -

0

7 -

0 -

pH

150 300

General Guidelines for Crevice Corrosion Resistance of Titanium in NaCl Brine Media

Temperature (ºC)

• 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 > 80ºC

Corrosion - Galvanic Effects

CPI companies use Ti

•Dow,Dupont

•Shell, Chevron, BP (AMOCO)

•Morton Salt

•Kerr-McGee

•Bayer

•Heinz

•BASF

Ti application in CPI

Ti lined reactor vessel for mining operation

Reactor Vessel

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

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

R=ResistanceS=Susceptible

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

Benefits-Corrosion Resistance (Performance)

Galvanic series-Sea water

Ti application

Sea water application

Centrifugal pumps

Ti application

Cast pump for handling sea water

Sea water application

Benefits-Density

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

Titanium Zirconium StainlessSteel

Nickel Copper

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

0

20

40

60

80

100

120

140

160

0 100 200 300 400 500 600 700Temperature (°F)

AS

ME

Des

ign

All

ow

./U

nit

Den

sity

(ksi

/lb

/cu

in

)

Grades 2,7&16Ti

Grade 3Ti

Grade 12Ti

Grade 9Ti (Gr18)

316L SS

Alloy 625

C-276

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

Mature Applications >30 yrs service history>30 yrs service history

Ti role in the CPI

Industry Typical Areas Titanium Equipment Date of First UseOrganic acid production

Chemical Plants Chlor-AlkaliSalt production

Chlorinated Hydrocarbons

Crude OverheadsRefineries Desulfurizing

Process cooling water

PlatingElectrowinning

Metal Finishing HydrometallurgicalAnodizing

Waste Treatment WAO Heat exchangers, autoclaves Early 1970's

Pulp/paper Mills Bleach plant Mixers, diffusion washers Mid to late 1950's

Heat exchangers, reactors, columns, piping, anodes

Heat exchangers, piping

Anodes, cathodes, baskets, drums, heaters, exchangers,

agitators, piping

Late 1960's

Early 1960's

Late 1950's to early 1960's

Ti role in the CPINewer Applications <20 yrs service history<20 yrs service history

Industry Typical Areas Titanium Equipment Use DateChemical/Refinery Mature + new

processes/conditionsPiping, tubing, advanced

grade selectionOngoing

Metals' Production Nickel Laterites 90'sCu Anodes Late 80's

Geothermal Mid 90'sPower Generation Service water Late 80's

Nuclear waste-Yucca Mt. ????

Oil & Gas Production Piping 90'sFire water piping

Water Treatment SCWO ???RO Units 90's

Clad vessels, piping, tubing, anodes, misc. equip.

CP & Alloy piping, vessels, formed plate

Alloy + CP piping, alloy sheet/billet

Piping, Heat exchangers

• 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

SUMMARY