Presentation on theme: "Corrosion Damage and prevention"— Presentation transcript:
1 Corrosion Damage and prevention How to light up 8 extra BULBS/household in Trinidad?Corrosion Damage and preventionRaj Nath Mehrotra
2 AGENDA Who am I? Why care about conserving energy? Energy and Corrosion?Types of CorrosionWays of preventing CorrosionWhat this means for Trinidad?Conclusions and RecommendationsQuestions
3 Who am I?30 years of academic, research and industrial sector experience. Greatest industry experience was with the leading energy manufacturer of India – NTPC Ltd. (makes over 30% of India’s energy needs)Physical Metallurgist, Corrosion specialist and failure analyst for the Energy sectorEducation:MBA – The University of Delhi, IndiaM. Tech & B. Tech - Indian Institute of Technology – Kanpur, IndiaPersonal: Friend to many, Confidante to a few, Husband to one, Father to one, Leader to more, Employee to one, Inspiration to some, Judge of none.
4 AGENDA Who am I? Why care about conserving energy? Energy and Corrosion?Types of Corrosion and Prevention MethodsWays of preventing CorrosionWhat this means for Trinidad?Conclusions and RecommendationsQuestions
5 Why care about conserving energy? 20.5% CAGRPer capital Energy use in Trinidad & Tobago
6 AGENDA Who am I? Why care about conserving energy? Energy and Corrosion?Types of Corrosion and Prevention MethodsWays of preventing CorrosionWhat this means for Trinidad?Conclusions and RecommendationsQuestions
7 Energy & Corrosion? Sector wise CprrCost Corrosion is the degeneration of materials by chemical reactions.Examples: Rusting of power plants, automobiles, buildings and bridges, Fogging of silverware, Patina formation on copper.Corroding PipeExample of aSector wise CprrCostCorrosion costs approx % of GDP of countries (1) across most sectors. Utility sector is most hit.Regardless, all affected sectors require energy directly or indirectlyDirect Cost: Material, Maintenance, Over-design, use of Costly materialIndirect Cost: Plant shut-down, loss of production, contaminations of products, loss of products (leakage etc.), liability in accidentsCost of Corrosion in USASector Breakup(1)
8 Significance of Corrosion: Utllities San Bruno, CA, USASep 2010 Gas Pipeline Explosion9 DeadCause: Pipeline Corrosion
9 Significance of Corrosion: Infrastructure Impact Charlotte, NC, USAMay 2000 Lowe’s Motor Speedway Bridge Collapse114 injuredCause: Structural Corrosion
10 Corrosion Process – The Concept Corrosion occurs because of the natural tendency for most metals to return to their natural state; e.g., iron in the presence of moist air will revert to its natural state, iron oxide. Corrosion requires 4 components in an electrochemical corrosion cell: 1) An anode; 2) A cathode; 3) A conducting environment for ionic movement (electrolyte); 4) An electrical connection between the anode and cathode for the flow of electron current. If any of the above components is missing or disabled, the electrochemical corrosion process will be stopped. Eg: Corrosion of Zinc by an acid solution-ZincOxidation reactionZn2+2e-Acidsolutionreduction reactionH+2(gas)flow of e-in the metalTwo reactions are necessary:-- oxidation reaction:-- reduction reaction:
11 AGENDA Who am I? Why care about conserving energy? Energy and Corrosion?Types of CorrosionWays of preventing CorrosionWhat this means for Trinidad?Conclusions and RecommendationsQuestions
12 Types of Corrosion Corrosion Uniform Corrosion Erosion Control GalvanicCrevicePittingIntergranularSelective LeachingErosion ControlStress Corrosion
14 Galvanic Series (Mg – Cu – Ni – Ag – Au – Pt) 2. Galvanic CorrosionDissimilar metals are physically joined in the presence of an electrolyte.The more anodic metal corrodes.Bilge pump - Magnesium shell cast around a steel core.Galvanic Series (Mg – Cu – Ni – Ag – Au – Pt)
15 3. Stress CorrosionFall of Silver Bridge 1967A structure that has SCC sensitivity, if subjected to stresses and then exposed to a corrosive environment, may initiate cracks and crack growth well below the yield strength of the metal.Consequently, no corrosion products are visible, making it difficult to detect or prevent; fine cracks can penetrate deeply into the part.
17 5. PittingPitting is a localized form of corrosive attack. Pitting corrosion is typified by the formation of holes or pits on the metal surface. Pitting can cause failure, yet the total corrosion, as measured by weight loss, may be minimal.Boiler tube304 stainless steel / acid chloride solution5th Century sword
18 6. Intergranular Corrosion along grain boundaries, often where precipitate particles form.
19 7. Erosion Corrosion Promoted by - High flow - Turbulent conditions Brass water pumpPromoted by- High flow- Turbulent conditions- Particulates in fluidCombined chemical attack and mechanical wear (e.g., pipe elbows).
20 8. Selective Leaching Preferred corrosion of one element/constituent [e.g., Zn from brass (Cu-Zn)]. Dezincification.
21 AGENDA Who am I? Why care about conserving energy? Energy and Corrosion?Types of CorrosionWays of preventing CorrosionWhat this means for Trinidad?Conclusions and RecommendationsQuestions
22 Corrosion Prevention zinc - 2e steel Galvanized Steel 2+ Zn Metal (examples: Al,stainless steel)Metal oxideUse metals that passivate, form a thin, adhering oxide layer that slows corrosion.Use metals that are relatively unreactive in the corrosion environment.Use inhibitors (substances added to solution that decrease reactivity); slow oxidation/reduction reactions by removing reactants like O2 gas by reacting it w/an inhibitor).Slow oxidation reaction by attaching species to the surface. Apply physical barriers: films and coatings, paintReduce T (slows kinetics of oxidation and reduction)Cathodic (or sacrificial) protection; attach a more anodic material to the one to be protected.steelzincZn2+2e-e.g., zinc-coated nailGalvanized Steel
23 Anodic Protection (1) Uses: Storage & handling of H2SO4 H2SO4 cooling heat exchangersVarious other misc. usesTranspassiveNoblePotential, EPassive- EpActiveActiveLog iicrit
24 Anodic Protection (2)Anodic protection is used in metals that behaves passively after certain anodic potential is applied as shown in figure below:VMaterials which have shown active passive behavior:Solution MetalSulfuric acid SteelsPhosphoric acid S. SteelsNitric acid NickelNitric Solution Nickel alloysAqueous Ammonia ChromiumReference electrodeWorking electrodeAuxiliary electrodeApparatus used for anodic polarization studies
25 Sacrificial AnodeThis field is located in Viosca Knoll, block 786, southeast of New Orleans. It lies in water depths of approximately 1754 feet (535 meters). Petronius is the largest free-standing structure in the world. Texaco's choice was Galvotec-CW-III Aluminum Sacrificial Anodes for their Petronius cathodic protection system.
26 Barrier ProtectionHere the metal is protected from atmosphere by creating barrier (coatings) that resist penetration. These are three types:Inorganic CoatingsCeramicPhosphateAnodic OxidesOrganic CoatingsInhibitors
28 AGENDA Who am I? Why care about conserving energy? Energy and Corrosion?Types of Corrosion and Prevention MethodsWays of preventing CorrosionWhat this means for Trinidad?Conclusions and RecommendationsQuestions
29 Corrosion is & will continue being chief problem hurting Trindad’s growth Energy equivalent to EIGHT 150W bulbs per household running 24 hours (1)Est. conservatively3% of GDP (2)==Proximity to SeaWet Corrosion==Dry/Gaseous Corrosion(High Temperature Corrosion)Dependence on Natural Gas(1) Assumes that only 25% of the cost of losses due to corrosion can be recovered. (2) Actual might be higher, esp. closer to 5% of GDP for Trinidad
30 AGENDA Who am I? Why care about conserving energy? Energy and Corrosion?Types of Corrosion and Prevention MethodsWays of preventing CorrosionWhat this means for Trinidad?Conclusions and RecommendationsQuestions
31 Conclusion & Recommendations Conclusion: Corrosion is a natural degenerative process affecting metals. It would continue to have paramount effect on any economy, more so on Trinidad & Tobago’s economy as it tries to grow.Recommendations:Educate & adopt Best practices for:StudentsPartnersIndustryResearch & Collaborate:Setup joint corrosion research labGather greater government attention and resourcesPartner with:Leading industriesTop worldwide universitiesTrinidad should set up a teaching discipline with in Engineering in the field of Metallurgy & Material Science to prepare future experts in:Metallurgy & Material SciencesReview StatusEstablish Corrosion awareness cell under leadership of UTT & CARIRICreate in conjunction with UTT, Gov. & Industry to establish Corrosion Research labEncourage all to adopt Corrosion & Corrosion mitigation programPrepare directory of world wide corrosion best practicesEmphasize the development of corrosion management practices for protection of environmentAdopt existing corrosion standardsMaterial selection ExpertsFailure Analysis / Damage Assessment and mitigationRemaining life estimation expertsNormalize education and certification requirements
32 AGENDA Who am I? Why care about conserving energy? Energy and Corrosion?Types of Corrosion and Prevention MethodsWays of preventing CorrosionWhat this means for Trinidad?Conclusions and RecommendationsQuestions
36 Est. Energy Recoverable from Corrosion – Details MetricCost ($ or otherwise)AssumptionsGDP (1)$ BCost of Corrosion$ MConservative estimate 3% of GDPCost which can be recovered$210.72M25% of total costs lost to corrosion. Ref: NACE International.Converting this costs in INR TermsINR MApprox. conversion rate 1 USD = 45 INREquivalent energy equipment that this cost saving can buyMWCost of energy installation: Est. INR 20M / MW (NTPC estimates)Power produced by this energy equipmentMwHNo of households in Trinidad (2)328000Energy / household27.75 kwHNumber of high-energy bulbs (150W) that this corresponds to8