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Condensate treatment in boilers refers to the process of treating the condensed water that is generated in the steam cycle of a boiler system. When steam is produced in a boiler, it condenses back into water after releasing its heat energy. This condensed water, known as condensate, is typically high in purity and can be reused within the boiler system. However, it needs to undergo treatment to remove impurities before it can be returned to the boiler.

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The primary purpose of condensate treatment is to protect the boiler system from corrosion and scale formation. Corrosion can occur when dissolved oxygen and carbon dioxide in the condensate react with metal surfaces, leading to the degradation of boiler components. Scale formation, on the other hand, is the accumulation of mineral deposits from the condensate, which can impede heat transfer and reduce the overall efficiency of the boiler.

Condensate treatment involves various steps to ensure the purity and quality of the water. These steps typically include filtration to remove suspended solids, ion exchange to remove dissolved ions, and chemical dosing to control pH levels and prevent corrosion. Some common chemicals used in condensate treatment include alkalizing agents like ammonia or amines to neutralize acidity, oxygen scavengers to remove dissolved oxygen, and filming amines to create a protective layer on metal surfaces.

Filming Amine

Filming amine is a type of organic compound that forms a protective film on metal surfaces in water treatment systems. Filming amine can prevent corrosion and scale formation by creating a barrier between the metal and the water. Filming amine is volatile and can distribute with the steam and condensate throughout the system. Filming amine can also neutralize carbonic acid and raise the pH of the condensate to reduce corrosion.

Filming amines are a type of water treatment chemicals that can protect boiler condensate lines from corrosion. They work by forming a thin film on the metal surface that prevents contact with corrosive substances such as carbonic acid and oxygen. Filming amine can be used in boilers, steam generators, condensate systems, and cooling systems to enhance heat transfer efficiency and equipment longevity . Filming amines are volatile, which means they can travel with the steam and reach the condensate lines. Filming amines have a strong affinity for metal due to the free electron pair on the nitrogen atom in the amine molecule. The film-forming amine molecule has a hydrophobic tail that pushes it away from the water and closer to the metal surface.

The chemical reaction of filming amines can be represented as follows:

R-NH2 + M ------> R-NH-M + H+

Where R is the hydrophobic tail of the filming amine, NH2 is the amine group, M is the metal surface, and H+ is a hydrogen ion. The R-NH-M bond is very strong and stable, and it creates a barrier against water and dissolved gases. The film also reduces the electrical conductivity of the metal surface, which lowers the corrosion rate.

Neutralizing Amine

Neutralizing amine in condensate lines refers to the use of specific chemical compounds known as amines to neutralize acidic conditions in the condensate water that is returned to the boiler. In the steam cycle of a boiler system, condensate is formed when steam releases its heat energy and condenses back into water. This condensate may contain dissolved gases, such as carbon dioxide, which can lower the pH and make the water acidic.

Neutralizing amines are added to the condensate lines to raise the pH of the water, reducing its acidity and preventing corrosion in the boiler and associated equipment. The amines work by reacting with the acidic components in the condensate, such as carbon dioxide, and forming a more alkaline compound.

The commonly used neutralizing amines include volatile amines like morpholine, cyclohexylamine, and diethylaminoethanol. These amines are selected based on their ability to effectively neutralize the acidic gases and maintain the desired pH level in the condensate.

The addition of neutralizing amines helps protect the internal surfaces of the condensate lines and boiler against corrosion caused by the acidic nature of the condensate. By maintaining an alkaline pH environment, the neutralizing amines minimize the risk of metal degradation, pitting, and erosion, thus extending the lifespan of the boiler system and ensuring its efficient operation.

The chemical reaction for neutralizing amine in condensate lines can be represented by the following general equation:


R-NH2 + HX → R-NH3+X-


In this equation, R-NH2 represents the neutralizing amine compound, HX represents the acidic component present in the condensate (such as carbon dioxide), and R-NH3+X- represents the resulting salt formed after the neutralization reaction.

when we used neutralizing amine or filming amine?

Neutralizing amines and filming amines are commonly used in boiler water treatment, but they serve different purposes and are applied in different situations.

  1. Neutralizing Amines: Neutralizing amines are primarily used in condensate treatment to raise the pH and neutralize acidic conditions in the condensate water before it is returned to the boiler. The acidic components, such as carbon dioxide, can cause corrosion in the boiler and associated equipment. By adding neutralizing amines, the pH of the condensate is increased, creating an alkaline environment that helps protect the boiler system from corrosion. These amines are dosed in the condensate lines or in the feedwater to maintain the desired pH level.

  2. Filming Amines: Filming amines, on the other hand, are used as corrosion inhibitors in the boiler water itself. They form a thin, protective layer on the metal surfaces of the boiler and prevent corrosive substances from coming into contact with the metal. Filming amines can provide long-term protection against corrosion, even during periods of low or no operation. They are typically added directly to the boiler water, either continuously or intermittently, to maintain the protective film.


The use of neutralizing amines and filming amines in boiler water treatment is often complementary. Neutralizing amines focus on neutralizing acidity in the condensate, while filming amines concentrate on protecting the boiler water itself. Both types of amines help prevent corrosion, but they target different areas of the boiler system.


It's important to note that the selection and application of neutralizing amines and filming amines depend on the specific boiler system, water chemistry, and operating conditions. Consulting with water treatment professionals or following manufacturer guidelines is crucial to determine the appropriate dosage and application method for these chemicals in boiler water treatment.

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