Product Note:
3-Methoxypropylamine as a neutralizing amine:
There are several different neutralizing amine components typically used in the treatment of boiler feedwater and/or condensate.
Neutralizing amines each have different chemical properties, and it is important to understand the differences so that the correct components can be applied.
Neutralizing amines typically applied in power plant systems are cyclohexylamine (CHA), methoxypropylamine (MPA), monoethanolamine (ETA), and morpholine.
Neutralizing amines are weak bases that are typically classified in terms of their neutralizing capacity,basicity, and distribution ratio.
The neutralizing capacity is a measure of how much amine it takes to neutralize a given amount of acid.
Usually it is expressed as the ppm of CO2 (or carbonic acid) neutralized per ppm of neutralizing amine.
Once the acid has been neutralized, each amine has a different ability to boost pH, which is accomplished by the hydrolysis of the amine to form hydroxyl (OH-) ions.
Distribution ratio refers to the volatility of the amine, which is one factor that helps determine how each amine component will partition between the liquid and steam phases.
The distribution ratio of a particular amine also influences how much amine is recycled throughout the system, and how much amine will be lost from the system via boiler blowdown and steam venting.
While neutralizing amine chemistry may appear to be relatively straightforward, it is in fact quite complex.
For example, the distribution ratio for a given amine is actually a function of pressure, temperature and pH.
This means if you feed more or less neutralizing amine in a given system and affect the pH, the distribution of the amine between the liquid and steam phases will change as well.
In addition, the chemistry of neutralization is actually based on equilibrium chemistry of weak acids and weak bases.
In many cases, there are multiple neutralizing amine components and acid components present so it becomes even more difficult to predict the amine distribution and pH profile across the system without using sophisticated computerized modeling techniques or without performing extensive empirical in-plant analyses.
The thermal stability of the neutralizing amine must also be considered when designing a treatment program to control FAC.
Most amines degrade to some degree in an aqueous, alkaline, high temperature environment to form carbon dioxide, organic acids and ammonia.
Morpholine, CHA, ETA, and MPA are considered the most thermally stable amines and are routinely employed in high-pressure power plant applications.
