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A class of inhibitors known as neutralizing amines or volatile amines is generally used to prevent afterboiler corrosion caused by low pH They neutralize carbonic acid and raise condensate pH Ammonia is also usually grouped with this class of inhibitors because its method of afterboiler corrosion prevention is through carbonic acid neutralization and pH increase.

Morpholine and Cyclohexylamine are the most commonly used neutralizing amines; others include Diethylaminoethanol, aminomethylpropanol, and methoxypropylamine.

Amines differ in cost, consumption rate and vapor-liquid distribution ratio. The distribution ratio (ratio of the amine concentration in the steam to that in the condensate) is important because it determines the amount of material present as the first portion of the steam condenses

Combining amines of differing distribution ratios provides an effective method of controlling corrosion throughout the afterboiler section.

Water Services Ltd produces and distributes two neutralizing amine product lines :

• WSB SLA mixtures based on Morpholine
• WSB DEA mixtures based on Diethylamino Ethanol

Cycloexylamine is included in all formulations, but there is not a product line based to it, because  has a relatively high distribution ratio, travels farther in the steam and reaches areas beyond those in which steam first condenses. 

This can actually result in concentration pockets of the neutral carbonate salt that may exceed the solubility limit and thus cause deposition and possible fouling of traps and lines. These deposits can include ammonium carbonate, Cyclohexylamine carbonate, and Morpholine carbonate

[ Up ] [ WSB SLA ] [ WSB DEA ]