Gunk or gum balls are a commonly reported problem on installations using film forming amines exposed to high DWD heat transfer surfaces and with contaminated oxide morphologies. This is a reported problem with thousands of documented cases accumulated over more than 30 years of experience.
Traditional film forming amines are not water soluble and are accordingly freely used in combination with several neutralizing amine/alkalizing amine product combinations to ensure product solubility and stability. However, the differences in volatility between the film forming active component and the neutralizing/alkalizing amines in which they co-exist, leads to a separation of products in the steam water cycle. The film forming amine thus forms an emulsion or micelles. These micelles can directly interact with dissolved or particulate iron to form gunk balls. This action is exacerbated when dosages and active residuals exceed 200 ppb.
The treatment action of conventional film forming amines is to thus, and in a non-selective manner, impart
a hydrophobic film on the surface of the semi protective or porous oxide that is in direct contact with the cooling medium.
Formation of an isolating hydrophobic film on the surface of the semi porous oxide is undesirable. This action may certainly result in short term decreases in oxide transport, but it will at the same time, increase significantly, the risk of under deposit corrosion as inorganic contaminants are trapped and isolated from the cooling medium.
Inorganic contaminants trapped within the oxide can also attack the film architecture and allow release of the same, leading to an additional source for localized corrosion and gum ball formation.
The use of these organic neutralizing and/or alkalizing amines should be a decision made with the associated risks in mind. See sections elimination of oxide transport problems and thermal stability for further related discussion.
Anodamine does not typically recommend nor do we employ a multi-component mix of amines into our specialty product formulations. The use of neutralizing or alkalizing amines is not mandatory with application of Anodamine. All Anodamine formulations are fully water miscible, emulsion free, hydrophobic film-forming technologies. Moreover, no risks of overdosing or gunk balls exist.
Some useful information on other FFA chemistries and their limitations such as waxy "gunk" ball formations can be found in the following publications: