Condensate Corrosion Inhibitor
- Reduce condensate corrosion
- Reduce maintenance costs
- Improve boiler system reliability
- Reduce the levels of iron and copper in boiler feedwater
Steamate NA1324 is a liquid blend of ammonia and a neutralising amine designed to meet the specific needs of boiler feedwater, boiler water and condensate systems.
Steamate NA1324 is designed to protect all parts of the steam/water system by chemically neutralising any weakly acidic species and maintaining the required pH.
Steam containing carbon dioxide forms a weakly acidic solution “carbonic acid” when condensation occurs. Metal loss due to carbonic acid is one of the major causes of condensate corrosion.
Feedwater alkalinity is the main source of carbon dioxide as bicarbonate and carbonate alkalinity break down at elevated temperatures as follows:
1) 2NaHCO3 + heat ^ Na2CO3 + CO2 + H2O
2) Na2CO3 + H2O + heat ^ 2NaOH + CO2
The first decomposition reaction proceeds to 100% completion whereas, the second reaction proceeds to about 80% completion.
At points of condensation, carbon dioxide dissolves in water to form carbonic acid. This depresses the pH of the condensate and causes etching of the metal. This characteristic acidic corrosion shows up as thinning and grooving of the metal at and below the water level.
If the corrosion is severe, failures could occur in condensate pipe work, vessels and heat exchangers. This would result in costly equipment replacement, maintenance and possible production losses.
Furthermore, iron and copper corrosion products returned to the boiler may cause deposition in areas of high heat flux, resulting in reduced energy efficiency. Iron deposits are very porous and may promote under deposit corrosion, thus reducing boiler reliability.
Protection
Condensate corrosion can be controlled by applying either neutralising amines and/or ammonia.
Neutralizing amines and ammonia perform two functions when applied as condensate corrosion inhibitors. Firstly, they neutralize the acidity imparted to the condensate by carbon dioxide. Secondly, they elevate the pH of the condensate to a range, where iron pick-up is reduced to a minimum.
There are several important properties that govern the effectiveness of a particular molecule.
- Neutralizing capacity: this is simply the quantity of neutralizing amine/ammonia required to neutralize a given quantity of carbon dioxide.
- Distribution ratio: this is a measure of the volatility of the neutralizing amine/ammonia under defined conditions.
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- Basicity: this is a measure of the ability of the neutralizing amine/ammonia to elevate the pH of the condensate after all the carbon dioxide has been neutralized.
Steamate NA1324 can provide the required volatility, neutralising capacity and basicity.
Treatment and Feeding Requirements
Feed point – Steamate NA1324 can be fed to the deaerator storage section, feedwater line, steam drum, or steam header.
In some systems, supplemental (“satellite”) feed points may be required to provide optimum system protection. This is especially true in complex multipressure steam/condensate systems with flash tanks and high alkalinity boiler feedwater.
Feedrate – The required feedrate of Steamate NA1324 depend on many factors particular to a given installation. The product feed rate is controlled by monitoring condensate pH, iron and copper levels.
Dilution – Steamate NA1324 can be fed neat, or diluted to any convenient strength with softened make-up, feedwater or condensate. Neutralizing amines can be fed along with most other internal treatment chemicals.
The physical properties of Steamate NA1324 are shown on the Safety Data Sheet, a copy of which is available on request.
Contact your local Veolia representative for details.
A Material Safety Data Sheet containing detailed information about this product is available on request.
Veolia Water Technologies
Please contact us via:
www.veoliawatertechnologies.com
