API 571: 4.3.5 BOILER WATER CONDENSATE CORROSION
Boiler Water Condensate Corrosion - Answer -General corrosion and pitting of boiler
system and condensate return piping.
What causes corrosion in boiler feed water and condensate return systems? - Answer -
Dissolved gases such as oxygen and carbon dioxide
How is protection achieved? - Answer -Hydrazine is used to remove oxygen
Deaerators are used to remove gases
Volatile amine inhibitor is used to remove carbon dioxide
The layer of protective film that covers the pipe is called? - Answer -It is called
magnetite
The lifetime of the boiler is highly dependent on? - Answer -Develop and maintain a
thin protective layer of iron oxides
What is a deaerator? - Answer -Deaerator is a device used to remove oxygen and
other dissolved gases from the feedwater to steam generating boilers. Reduce oxygen
down to 7ppb by weight and essentially eliminating carbon dioxide.
How is oxygen removed? - Answer -It can be removed by hydrazine, it converts oxygen
to water
What is an economizer? - Answer -In a boiler, it essentially pre heats the feedwater
used to fill up the boiler.
How does corrosion from oxygen appear? - Answer -Appears as pitting type damage,
can show up anywhere even if only small quantities break through the scavenging
treatment. Oxygen is aggressive in equipment such as closed heaters and economizers
where there is a rapid rise in water temperature.
How does carbon dioxide corrosion appear? - Answer -It forms carbonic acid and tends
to be smooth grooving on the pipe wall.
What is a corrosion inhibitor? - Answer -It slows the corrosion rate. Can form protective
layer inside to prevent access of corrosion substance on the surface.
How is carbon dioxide removed? - Answer -Volatile anime inhibitors neutralizes acidic
carbon dioxide and shifts ph to less acidic, in some cases it forms a protective layer on
the surface that protects and is also anodic. It acts as an anodic inhibtor.
How is it inspected? - Answer -Monitoring is the main way by monitoring ph,
conductivity, chlorine, or residual biocide.
Boiler Water Condensate Corrosion - Answer -General corrosion and pitting of boiler
system and condensate return piping.
What causes corrosion in boiler feed water and condensate return systems? - Answer -
Dissolved gases such as oxygen and carbon dioxide
How is protection achieved? - Answer -Hydrazine is used to remove oxygen
Deaerators are used to remove gases
Volatile amine inhibitor is used to remove carbon dioxide
The layer of protective film that covers the pipe is called? - Answer -It is called
magnetite
The lifetime of the boiler is highly dependent on? - Answer -Develop and maintain a
thin protective layer of iron oxides
What is a deaerator? - Answer -Deaerator is a device used to remove oxygen and
other dissolved gases from the feedwater to steam generating boilers. Reduce oxygen
down to 7ppb by weight and essentially eliminating carbon dioxide.
How is oxygen removed? - Answer -It can be removed by hydrazine, it converts oxygen
to water
What is an economizer? - Answer -In a boiler, it essentially pre heats the feedwater
used to fill up the boiler.
How does corrosion from oxygen appear? - Answer -Appears as pitting type damage,
can show up anywhere even if only small quantities break through the scavenging
treatment. Oxygen is aggressive in equipment such as closed heaters and economizers
where there is a rapid rise in water temperature.
How does carbon dioxide corrosion appear? - Answer -It forms carbonic acid and tends
to be smooth grooving on the pipe wall.
What is a corrosion inhibitor? - Answer -It slows the corrosion rate. Can form protective
layer inside to prevent access of corrosion substance on the surface.
How is carbon dioxide removed? - Answer -Volatile anime inhibitors neutralizes acidic
carbon dioxide and shifts ph to less acidic, in some cases it forms a protective layer on
the surface that protects and is also anodic. It acts as an anodic inhibtor.
How is it inspected? - Answer -Monitoring is the main way by monitoring ph,
conductivity, chlorine, or residual biocide.
