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Nickel Institute Corrosion by Process Waters R. W. Ross Consultant Nickel Institute.

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Presentation on theme: "Nickel Institute Corrosion by Process Waters R. W. Ross Consultant Nickel Institute."— Presentation transcript:


2 Nickel Institute

3 Corrosion by Process Waters R. W. Ross Consultant Nickel Institute

4 Summary Scaling and Corrosion Scaling and Corrosion Effects of Velocity Effects of Velocity Biological Effects Biological Effects Chlorides Chlorides Rouging of SS Rouging of SS

5 Water Chemistry Effects Corrosion Dissolved Oxygen Dissolved Oxygen Chlorides Chlorides pH pH Hardness Hardness Temperature TemperatureScale Dissolved Solids Dissolved Solids Calcium Ions Calcium Ions pH pH Temperature Temperature

6 Water Chemistry Effects

7 Corrosion Of Carbon Steel In Water 72 ºF (22 ºC) 104 ºF (40 ºC) Corrosion Rate, mpy pH of Water Corrosion Rate, mm/y

8 Corrosion Of Carbon Steel In Low-velocity Water

9 Corrosion Of Carbon Steel Effect Of Velocity In Seawater ~ 72 ºF (22ºC ) ft/sec (m/s) Corrosion Rate, mpy Corrosion Rate, mm/y (1.5)(3.0)(4.7)(6.1)(7.6)

10 Erosion-corrosion - Inlet

11 Erosion-corrosion Flow

12 Erosion-corrosion Tube Blockage Flow

13 High-velocity Seawater >120 fps (36.6 m/s) Corrosion Rate, Alloy mpymm/y Alloy mpymm/y 625/C-276 <1< /K-500 <1< /725/925 <1< 0.03 T-304/T-316 <1< 0.03 C Steel >300> 7.62

14 Biological Effects Macrofouling MusselsMussels ClamsClams BarnaclesBarnacles Plant LifePlant Life

15 Biological Effects Macrofouling

16 Bacteria Effects - MIC (Microbiologically Induced Corrosion) Species OxygenMetalsCorrosive Desulfovibrio NoFe, Al, Cu Sulfide Thiobacillus YesFe, CuSulfuric Acid Gallionella YesFeFe ++ to Fe +++ Mn ++ to Mn +++

17 Type 304 SS water tank 8 months of service Guam Bacteria Effects - MIC

18 Bacteria Effects - MIC (Type 304 SS, Before Cleaning)

19 Bacteria Effects - MIC (After Cleaning) 0.15 in. (3.8) mm) Max. Attack

20 Bacteria Effects - MIC (After Cleaning - No Attack)

21 Prevention Of MIC Keep The System CleanKeep The System Clean Keep Water Flow > 6 fps (2 m/s)Keep Water Flow > 6 fps (2 m/s) Use Bactericide:Use Bactericide: – Chlorine – Chlorine Dioxide – Hypochlorite – Ozone – Non-oxidizing

22 Prevention Of MIC Use Continuous CleaningUse Continuous Cleaning Use High Pressure HydrolancingUse High Pressure Hydrolancing Use Stainless Steel ScrapersUse Stainless Steel Scrapers (Hard to Remove or Heavy Deposits) Use Alloy Resistant to MICUse Alloy Resistant to MIC

23 Prevention Of MIC - 6% Mo ALLOY

24 Effects of Chlorides

25 Crevice Corrosion Type 303

26 Stainless Steels Localized Corrosion Resistance Alloy PRE Alloy PRE /Alloy % Mo Alloys % Mo Alloys

27 Nickel Alloys Localized Corrosion Resistance Alloy PRE Alloy PRE % Mo 40 – 45 6% Mo 40 – / / C C

28 Stainless Steels for Use in Waters Potable water Type 304 < 200 ppm chlorides Type 316 < 1000 ppm chlorides River water Risk of MIC if water is not treated Use type 316 or higher Mo grades: L L Mo Mo Well water Risk of MIC if water is not treated Use type 316 or higher Mo grades

29 Do not confuse Chloride Cl - and Chlorine Cl 2 Maximum Concentration (ppm) in Water to Avoid Crevice Corrosion Chloride Cl - Chlorine Cl Shock dosing, such as 25 ppm chlorine for 24 hours, is common practice and has not been found to cause problems.

30 Stress Corrosion Cracking (SCC) Steam Line

31 Chloride SCC Duplex vs T-316 Stainless Steel (315) (204) (93) Type Cr Duplex 22 Cr Duplex No cracking below lines

32 Effect of Nickel Content on Stress Corrosion Cracking Boiling 45% MgCl 2 No SCC SCC 6% Mo SS Duplex SS Ni Alloys


34 How does external environment affect process equipment?

35 Marine Corrosion of C Steel Relative Corrosion Rates* – Vary with Sea Conditions Atmospheric Splash Tidal Submerged Subsoil 5 mpy (0.13 mm/y) 25 mpy (0.64 mm/y) *Protected Harbor

36 Uniform Corrosion

37 Effect of Chromium Weight Loss, mg. / sq. dm. % Chromium 250M Lot 44 Months

38 Alloy C in Marine Atmosphere 56 Years of Exposure


40 Type 304 Fastener In Marine Tide After 6 Months

41 Type 304 Fastener Above Marine Tide After 6 Months

42 Crevice Corrosion

43 Crevice Corrosion of Alloy 825 Heat Exchanger Tubing – Shell Side 85° F, Aerated Seawater

44 Crevice Corrosion of Alloy 625 Waterbox With Deaerated, Treated Seawater 165° F 235° F ° F

45 Crevice Corrosion of Alloy 825 Heat Exchanger Tubesheet – Water Side 225° F, Deaerated, Treated Seawater Tube to Tubesheet Joint

46 Types Of Severe Crevices Stationary O Rings Flange Face Under Gasket Non-Metallic Connector Tube to Tubesheet Joint

47 Corrosion of Cu-Ni in Seawater Corrosion Rate, mpy

48 Marine Fouling 18 Months in Quiet Seawater Aluminum C Steel

49 Fouling of Titanium Waterbox 3 mo. Exposure

50 Fouling of Titanium Waterbox 6 mo. Exposure

51 Effect of Chlorination <1 fps Seawater Flow

52 90-10 Cu-Ni Alloy Fouling - Quiet Seawater 3 Mo 9 Mo 18 Mo 3 Yr 4 Yr 5 Yr

53 90-10 Cu-Ni Intake Piping Desalination Plants

54 90-10 Cu-Ni Alloy Seawater Piping Systems

55 90-10 Cu-Ni Alloy Seawater Heat Exchangers

56 Pumps - Impellers

57 Rouging of Stainless Steels High Purity Water Water For Injection (WFI)

58 Why Use Stainless Steels (316L) for Pharma & Biotech? Good corrosion resistance and excellent batch to batch cleanability Good structural properties for process equipment Easily formed, fabricated and welded

59 What about Rouging? What is Rouging? Rouging is a general term used to describe several species of predominately iron oxide deposits on the wall of piping and vessels in high purity water systems.

60 Rouging is not New! Rouging is not unique to the pharmaceutical and biotech industries. Was recognized over 40 years ago with rouging of SS vessels at Savannah River.

61 Where is Rouge often Found Water systems, usually high purity water and clean-steam systems Distillation and clean-steam generating equipment Rouge found on wall of vessels, piping and polymer gaskets (Teflon ® ) downstream of where originated

62 Is Rouge Harmful? No reports or evidence that rouging is precursor to a SS corrosion failure. We are not in a position to comment on whether rouge is harmful to the product being produced. Common practice is to remove rouge.

63 Generally a loose powdery deposit, but can be tightly adherent Hydrated or partially hydrated ferric oxide (Fe 2 O 3 ) or ferroso-ferric oxide (Fe 3 O 4 ) Usually occurs in high purity ( µS/cm), high temperature water (60 – 100 C) Rouging

64 Reddish brown rust color, but can range from orange to blue-black. Origin is uncertain but generally thought to be ions or colloids that are formed at one location and transported in the solution to another where they are precipitated. Removed by acid cleaning in nitric, phosphoric, citric, or oxalic acid. Rouging

65 Type 1 – Corrosion of Steel, Deposits Downstream Pumps prime suspects – cavitation or erosion when velocity over ~ 100fps and higher temperatures Delta ferrite in cast impellers may contribute by eroding easier and higher iron content Type 2 – Corrosion Product of Stainless Steel Type 3 – Corrosion Product of Stainless Steel in Steam Systems > 100 C Rouging - Types

66 Rouging of Stainless Steels

67 Rouging over 4 years inside electropolished Type 316L - column still used to produce ultra- pure water for pharmaceutical use

68 Rouging of Stainless Steels

69 De-rouging & Passivation 3 Steps Cleaning – detergent wash followed by thorough water rinse De-rouging chemical treatment Passivation followed by thorough water rinse

70 Electrochemical Coloring Proprietary electrochemical processes – invented in 1972 by Inco, further developed in Japan Interference between the light beams refracted from the substrate and the surface of the oxide film creates colorInterference between the light beams refracted from the substrate and the surface of the oxide film creates color Appearance and color vary with immersion time and surface finishAppearance and color vary with immersion time and surface finish Incidentlight Color Oxide

71 Experience Music Project

72 Summary Discussed Scaling and Corrosion Discussed Scaling and Corrosion Described Effects of Velocity Described Effects of Velocity Reviewed Biological Effects Reviewed Biological Effects Discussed Chlorides Discussed Chlorides Summarized Rouging of SS Summarized Rouging of SS

73 Questions ?

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