Filming Amine (Aliphatic Amine) Test Kits

The Methyl Orange Method

This three minute CHEMetrics procedure uses the industry standard methyl orange chemistry and features a unique extraction technique. The extraction eliminates several steps required in other procedures and increases the sensitivity of the test. The filming amine compound reacts with methyl orange to form a yellow-coloured complex that is extracted into an immiscible organic solvent. Results are expressed in ppm (mg/l) Octadecylamine (ODA).

The filming amine test kit K-1001 can be used in conjunction with the CHEMetrics Comparator Light Source (CLS), an independent light source for use in low-light conditions.

Reference:
ASTM D 2327-80, Mono- and Dioctadecylamines in Water.

Technical Data Sheet

The Rose Bengal Method

The kits that employ the standard Rose Bengal method employ our self-filling ampoule technology which eliminates the time-consuming, repetitive process of cleaning cuvettes that plagues other test kits that employ this chemistry. They are applicable primarily for the analysis of boiler water. When buffered under acidic conditions (pH 2.3 – 3.3), the sample forms a magenta complex with rose bengal (4,5,6,7-tetrachloro-2′,4′,5′,7′-tetraiodofluorescein disodium salt) in direct proportion to the concentration of filming amines such as Octadecylamine (ODA) or Oleylamine (OA).

Reference:
K Stiller, T Wittig, M Urschey. ‘The Analysis of Film-Forming Amines – Methods, Possibilities, Limits and Recommendations’, 2010

Technical Data Sheet

Applications

Filming Amines (aliphatic amines) are water treatment chemicals commonly used in high pressure boilers, cooling systems, and heat recovery steam generators (HRSGs) to prevent corrosion of metal surfaces. They are applied to different components of the steam cycle including the boiler feedwater, generator, and condensate return lines.

Filming amines are fed continuously into boiler feedwater to protect metal surfaces from corrosion caused by dissolved oxygen and carbon dioxide in condensate water. The amine forms a thin film on the surfaces that repels the potentially corrosive water. They are frequently dosed in conjunction with neutralising amines such as cyclohexylamine which are used to raise the pH to prevent acid corrosion.

Correctly measuring the amount of film forming amine in your system is critical for optimum performance of your system. Underdosing a system can leave it vulnerable to corrosion such as pitting. Overdosing can lead to the creation of micelles, or “gunk balls” as they are commonly known. These can lead to clogged pipes and reduced efficiency. Frequent and consistent filming amine analysis is a best practice to ensure dosing is at the correct levels.

FFAPs offer protection from corrosion, reduced corrosion product transport, prevention of scale build-up, smooth heat transfer surfaces, and protection of equipment during shutdown or layups. FFAPs can be used alongside or replace conventional corrosion inhibitor treatment regimes.

What are Film Forming Amines?

Amines are derivatives of ammonia (NH₃) where one or more hydrogen atoms is replaced by a carbon-based molecule to form either an aliphatic amine or an aromatic amine. An amine is characteristed by the presence of one or more amine groups (-NH₂). Aliphatic amines contain carbon chains, normally with single covalent bonds, e.g. alkyl amines based on alkanes, such as propane or butane etc. Aromatic amines contain an aromatic carbon (benzene) ring - an aryl group. Aliphatic amines can comprise of very long carbon chains. Amines are basic, like ammonia, but are a weaker base than metal hydroxides, and react readily with acidic substances in solution. The amine group or head bonds readily with a metal surface owing to the free election pair forming a complex with the metal.

Aliphatic amines are typically insoluble and hydrophobic because of the carbon chain molecular structure, and the hydrophobic properties tend to push the amine to the surface or edge of the water where the head bonds with any metal surfaces present, forming a protective, water repellent, monomolecular film. This is why aliphatic amines, particularly those with 10 to 18 carbon atoms in the chain, are ideal candidates for corrosion inhibitors in boiler feedwater.Aliphatic amines are commonly referred to as Filming Amines, Film Forming Amines (FFAs), Film Forming Amine Product (FFAP), or Film Forming Products (FFP).

In the context of FFAs usage in boiler systems, this property allows the FFA to act as a corrosion inhibitor by coating metal surfaces and system piping with a hydrophobic layer, minimising the amount of corrosive condensate forming on those metal surfaces; and also minimising the amount of dissolved gasses reaching the metal surfaces.

A common FFA used in boiler systems is Octadecylamine (ODA) with the formula CH₃(CH₂)₁₆CH₂NH₂, which is a straight carbon chain with a single amine group. Another is Oleylamine (OA) with the formula CH₃(CH₂)₇CH=CH(CH₂)₇CH₂NH₂, which contains a single carbon double bond and a single amine group.