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Protection of Condensers in Power Plants with High Performance Polymeric Compounds. Written By: Ricardo Chang. Presented By: Don Hilliard. Essential Parts of a Condenser. Types of Corrosion. Pitting Corrosion Crevice Corrosion. Types of Corrosion.
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Protection of Condensers in Power Plants with High Performance Polymeric Compounds Written By: Ricardo Chang Presented By: Don Hilliard
Types of Corrosion • Pitting Corrosion Crevice Corrosion
Types of Corrosion • Intergranular Corrosion - Corrosion Fatigue • Galvanic Corrosion
Types of Corrosion • Stress Crack Corrosion • Flow Induced Corrosion • Impingement Corrosion • Entrainment Corrosion • Cavitation
Corrosion is… • “A gradual wearing away or alteration by a chemical or electromechanical oxidizing process”
Ferrous Alloys Corrode • Water • Velocity • Acidity • Motion • Temperature • Bacteria / Salts / Aeration
Basic Corrosion Cell • Anode • Cathode • Conductor between Anode and Cathode • Electrolyte (salt or acid solution)
Galvanic Series • CORRODED END (ANODIC) Magnesium Lead Silver Solder Magnesium Alloys Tin Nickel (passive) Zinc Nickel (active) Inconel (passive) Aluminum 2S Inconel (active) Hastalloy C (passive) Cadmium Hastelloy C (active) Silver Aluminum 17ST Brass Graphite Steel or Iron Copper Titanium Cast Iron Bronzes Zirconium Carbon Steel Copper – nickel alloys Gold Stainless Steel Monel Platinum PROTECTED - END (CATHODIC)
Galvanic Corrosion • The # 1 Problem in Condensers • Also • Pitting • Crevis
Solutions to Prevent Corrosion • Cathodic Protection • Specialty Alloys • Barrier Coatings
Some Considerations • Surface must be cleaned with an angular abrasive to obtain a near white metal finish with a 3-mil surface profile. • Surface must be dry and free from contaminants. • Often several coats must be applied. • Cure times may be excessive. • Finished surface must be free from pin holes or holidays (detection is required). • Low heat transfer coefficients.
In Conclusion: • Equipment in wet operating conditions will corrode!!!!!
Barrier Coatings can Provide: • Low Cost • Long Lasting Solution To the overall problem of corrosion