Lay-up Protection for Boilers and HRSGs - American Public Power ...

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LP SH IP SH DA LP Drum Feedwater Preheater From HP FW Pump 46 HP Economizer IP Economizer HP Economizer LP Evaporator IP Drum To IP Turbine To LP Turbine HP Evaporator HP Econmizer IP Evaporator HP Drum --Nitrogen Addition Points --Chemical Sampling Points Drain Drain To HP Turbine HP SH
Wet Chemical <strong>Lay</strong>-<strong>up</strong> • Requires significant amounts of chemical • Must add nitrogen or steam provide adequate protection above the water line • May create an environmental issue if you have to drain the HRSG (particularly if hydrazine is used) 47
Page 1 and 2: Lay-up Protection for Boilers and H
Page 3 and 4: Goals of Proper Lay-up • Minimize
Page 5 and 6: Lay-up is Critical for HRSG’s •
Page 7 and 8: Your Choice Passivation and Protect
Page 9 and 10: Oxygen Pitting Causes: • Downtime
Page 11 and 12: Normal Passivation Half Reactions F
Page 13 and 14: Oxygen Pitting Deposits create a lo
Page 15 and 16: Corrosion Fatigue Causes: • Oxyge
Page 17 and 18: Underdeposit Corrosion Causes: •
Page 19 and 20: Lay-up Considerations Quick return
Page 21 and 22: Corrosion Triangle 21
Page 23 and 24: Wet Lay-up — Excludes Oxygen 23
Page 25 and 26: Design Issues Affecting Layup • C
Page 27 and 28: Dry Lay-up Advantages • Only opti
Page 29 and 30: Steps for Dry Lay-up • Drain HRSG
Page 31 and 32: Dehumidified Air • Air must circu
Page 33 and 34: Vapor Phase Inhibitors • Used on
Page 35 and 36: VPI Preservation After 30 days Afte
Page 37 and 38: Wet Lay-up Disadvantages • Requir
Page 39 and 40: Nitrogen Cap Cap should be applied
Page 41 and 42: Nitrogen Addition Points Vent HP Tu
Page 43 and 44: Nitrogen Cap- Drums • Enters the
Page 45: Wet Chemical Lay-up • pH of water
Page 49 and 50: Transitions Wet to Dry (Cold) • D
Page 51 and 52: Startup Chemistry Dry Lay-up Boiler
Page 53 and 54: Startup Chemistry Wet Lay-up (Nitro

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