14Bacteria Effects - MIC (Microbiologically Induced Corrosion) Species Oxygen Metals CorrosiveDesulfovibrio No Fe, Al, Cu SulfideThiobacillus Yes Fe, Cu Sulfuric AcidGallionella Yes Fe Fe++ to Fe+++Mn++ to Mn+++
15Bacteria Effects - MICType 304 SS water tank8 months of serviceGuam
16Bacteria Effects - MIC (Type 304 SS, Before Cleaning)
17Bacteria Effects - MIC (After Cleaning) 0.15 in. (3.8) mm)Max. Attack
18Bacteria Effects - MIC (After Cleaning - No Attack)
19Prevention Of MIC Keep The System Clean Keep Water Flow > 6 fps (2 m/s)Use Bactericide:ChlorineChlorine DioxideHypochloriteOzoneNon-oxidizing
20Prevention Of MIC Use Continuous Cleaning Use High Pressure HydrolancingUse Stainless Steel Scrapers(Hard to Remove or Heavy Deposits)Use Alloy Resistant to MIC
24Stainless Steels Localized Corrosion Resistance Alloy PRE2507/Alloy6% Mo Alloys
25Nickel Alloys Localized Corrosion Resistance Alloy PRE6% Mo – 4522/C
26Stainless Steels for Use in Waters Potable waterType 304 < 200 ppm chloridesType 316 < 1000 ppm chloridesRiver waterRisk of MIC if water is not treatedUse type 316 or higher Mo grades:LMoWell waterUse type 316 or higher Mo grades
27Do not confuse Chloride Cl- and Chlorine Cl2 Maximum Concentration (ppm) in Water to Avoid Crevice CorrosionChloride Cl-Chlorine Cl2304200231610004Shock dosing, such as 25 ppm chlorine for 24 hours, is common practice and has not been found to cause problems.
55Rouging of Stainless Steels High Purity Water Water For Injection (WFI)
56Why Use Stainless Steels (316L) for Pharma & Biotech? Good corrosion resistance and excellent batch to batch cleanabilityGood structural properties for process equipmentEasily formed, fabricated and welded
57What about Rouging. What is Rouging 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.
58Rouging 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.
59Where is Rouge often Found Water systems, usually high purity water and clean-steam systemsDistillation and clean-steam generating equipmentRouge found on wall of vessels, piping and polymer gaskets (Teflon®) downstream of where originated
60Is 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.
61Rouging Generally a loose powdery deposit, but can be tightly adherent Hydrated or partially hydrated ferric oxide (Fe2O3) or ferroso-ferric oxide (Fe3O4)Usually occurs in high purity ( µS/cm),high temperature water (60 – 100 C)
62RougingReddish 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.
63Rouging - TypesType 1 – Corrosion of Steel, Deposits DownstreamPumps prime suspects – cavitation or erosion when velocity over ~ 100fps and higher temperaturesDelta ferrite in cast impellers may contribute by eroding easier and higher iron contentType 2 – Corrosion Product of Stainless SteelType 3 – Corrosion Product of Stainless Steel in Steam Systems > 100 C
67De-rouging & Passivation 3 Steps Cleaning – detergent wash followed by thorough water rinseDe-rouging chemical treatmentPassivation followed by thorough water rinse
68Electrochemical Coloring Proprietary electrochemical processes – invented in 1972 by Inco, further developed in JapanInterference between the light beams refracted from the substrate and the surface of the oxide film creates colorAppearance and color vary with immersion time and surface finishIncidentlightColorOxide