49544

Corrosion of stainless steel with diluted sulphuric acid [Egypt] 

August 1, 2008

I am working in ammonium sulphate , we are feeding ammonia with sulphuric acid in a reactor then making evaporation for solution to produce the salt , produced vapor condensed in a shell and tube heat exchanger by action of cold water, by time noticed fouling of the heat exchanger by forming calcium carbonate as scales which decrease heat transfer, we started to add sulphuric acid to cold water to react with scales and try to keep ph from 7.4 to 8.2 but at some time may ph decrease to 6 or 6.5
we noticed apperance of leakage in tubes of condenser
my question is , is the diluted sulphuric acid with water which keep ph 6 or 6.5 can corrode stainless steel 316 l or there are any thing else

Ahmd Nadr
process engineer - Egypt, Suez