description and use

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.

problem description

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:

2NaHCO3 + heat  Na2CO3 + CO2 + H2O
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.

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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.

condensate corrosion protection

Condensate corrosion can be controlled by applying either neutralising amines and/or ammonia.

Neutralising amines and ammonia perform two functions when applied as condensate corrosion inhibitors. Firstly, they neutralise 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.

Neutralising capacity: this is simply the quantity of neutralising amine/ammonia required to neutralise a given quantity of carbon dioxide.
Distribution ratio: this is a measure of the volatility of the neutralising amine/ammonia under defined conditions.
Basicity: this is a measure of the ability of the neutralising amine/ammonia to elevate the pH of the condensate after all the carbon dioxide has been neutralised.

Steamate NA1324 can provide the required volatility, neutralising capacity and basicity.

Find a contact near you by visiting www.veoliawatertechnologies.com and clicking on “Contact Us.”

*Trademark of VEOLIA; may be registered in one or more

countries.

E-FSbSteamateNA1324_EN.docx Feb-10

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 multi-pressure steam/condensate systems with flash tanks and high alkalinity boiler feedwater.

Feed rate – The required feed rate 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. Neutralising amines can be fed along with most other internal treatment chemicals.