What is condensate and why does it need to be treated?
Condensate is the term used to describe the near-pure water that is created as steam from a boiler cools and condenses. However, there are some impurities that often require treatment. Carbon dioxide is a chemical that can become problematic because of its high volatility and ability to form carbonic acid. Carbonic acid is very corrosive and can dramatically lower the pH of the condensate. Often times the condensate is recycled back to the boiler's feedwater line because it is more energy efficient to use than cool, non-treated feedwater. Treated condensate is especially important to this process because it aids in preventing further corrosion of the boiler.
Typical condensate treatment begins with amines. Amines are derivative compounds formed when one or more hydrogen atoms of an ammonia molecule is replaced by a given organic molecule.
Amines fall in to two categories; volatile and filming.
- Volatile amines are categorized with respect to the range of distances the chemical can travel while remaining effective (short, medium, or long range). Amines also quickly dissolve into solution and have the ability to evaporates off with the steam because of their high volatility. Their volatility makes these amines safe to use throughout the whole boiler system because they do not leave behind any unwanted residuals.
- Filming amines on the other hand do not dissolve in to solution. This means they should never be used in boilers. Rather they are typically injected into the steam head where the steam disperses the amines evenly throughout the condensing pipes. As this happens the polarized molecules adhere to the lining of the pipe creating a hydrophobic layer between the water and the pipe.