This is the likely composition of the stream that enter into the economiser
Inlet gas 250C ,40psig
compositon : Nitrogen 65% ,water 15% ,NO2 13% ,O2 7%
Boiler water treatment :
Pre-treatment
Lime softened
Base exchanged
Dearation
Mechanical (Vacuum)
Chemical-sodium sulphate
Composition
Chloride: 10-20ppm
Max. O2 : 20ppb
NaOH : 100-300ppm
Shut Down: 1 week
Thanks