How to Differentiate Ammonium Chloride from Ammonium Bisulfide Corrosion in REAC?

[Guest102023]

I'm looking for all the relevant indicators, including visual appearance, corrosion compounds, etc.

.

"If you don't have time to do the job right the first time, when are you going to find time to repair it?"

 

[DBreyer]

My experience is that Ammonium Chloride corrosion will mainly be corrosion under deposits (black colour)so look for the deposits. I have most often seen it as pitting/shallow pit corrosion.
Ammonium bisulfide corrosion, on the other hand, occours at high velocity locations (air cooler headers, pipe bends) and leads to general thinning like erosion. Best way to have an indication if NH4HS corrosion is likely is to analyze the sour water of the cold seperator vessel for its ammonia content.
Additional Info can be found in API RP 932-B Design, Materials, Fabrication, Operation, and Inspection Guidelines for Corrosion Control in
Hydroprocessing Reactor Effluent Air Cooler (REAC) Systems
and in NACE 97490 CORROSION OF REACTOR EFFLUENT AIR COOLERS

Hope this helps


Daniel Breyer
Inspection Engineer

http://lnkd.in/dFcQA-w