Hydrazine (N2H4) and its hydrate form (N2H4·H2O) are commonly used as anti-corrosion additives in the water systems of thermal and nuclear power plants, particularly in boilers and feedwater systems. The primary purpose of using hydrazine in these applications is to prevent corrosion by removing dissolved oxygen from the water. Here’s how it works:
Mechanism of Action:
1. Oxygen Scavenging: Hydrazine reacts with dissolved oxygen (O2) in the water to form water (H2O). This reaction can be represented as: N2H4 + O2 →2H2O + N2
By removing oxygen, hydrazine prevents oxidative corrosion of metal surfaces, which can lead to pitting and other forms of localized corrosion.
2. Passivation: In addition to oxygen scavenging, hydrazine can also passivate metal surfaces by forming a protective oxide layer on the metal surfaces, particularly in the case of iron-based alloys. This layer helps to further inhibit corrosion.
Benefits:
Corrosion Prevention: By eliminating oxygen, hydrazine reduces the risk of corrosion, extending the life of the plant's components.
Boiler Integrity: Maintaining low levels of dissolved oxygen in boiler water helps prevent corrosion that could compromise the integrity of the boiler tubes and other components.
Efficiency: Reducing corrosion improves the overall efficiency of the power generation process by maintaining optimal heat transfer properties and reducing maintenance downtime.
Specifications:
| Items |
Units |
Standards |
Results |
| Appearance |
|
Colorless |
Colorless |
| Hydrazine Hydrate |
% |
100.0 Min |
100.31 |
| Iron(Fe) |
% |
0.01 Max |
0.0018 |
| Heavy Metal(Pb) |
% |
0.0005 Max |
<0.0001 |
| Chloride(Cl) |
% |
0.003 Max |
<0.0001 |
| Sulfate(SO4) |
% |
0.0005 Max |
<0.0001 |