1. What chemicals prevent oxygen corrosion?
Hydrazine and derivatives (DEHA, carbohydrazine). Sodium sulfite for lower pressure systems. Maintain reducing conditions (<7 ppb O₂). Must be properly dosed. Deaerators provide primary protection.
2. How does phosphate treatment work?
Forms protective calcium phosphate layer. Buffers pH to prevent acidic/caustic corrosion. Disperses sludge particles. Coordinated phosphate/pH control critical. Modern low-phosphate programs available.
3. What are neutralizing amines?
Morpholine, cyclohexylamine, DEAE. Neutralize carbonic acid. Raise feedwater pH. Volatile to distribute throughout system. Selected based on distribution ratios.
4. How is blowdown controlled?
Continuous blowdown maintains steady levels. Intermittent blowdown removes sludge. Automated based on conductivity. Heat recovery improves efficiency. Typically 1-5% of steam flow.
5. What are treatment monitoring requirements?
Continuous online pH/conductivity. Daily manual sampling. Weekly complete analysis. Corrosion coupon monitoring. Deposit analysis during outages.
