TEMA (Tubular Exchangers Manufacturing Association) is the preferred standard for the manufacture of shell and tube heat exchangers. The general descriptions of the three major TEMA classes are:
TEMA C – General Service
TEMA B – Chemical Service
TEMA R – Refinery Service
regards
luis
To restart water washing, with your device, maybe let´s say, within 24 hours, is to improvise a paralel device, by doing hot tap, while waiting a better oportunity to shut down the unit.
Yeh! Amonium chloride is the strongest possibility, I don´t see a way to unplugg it on line. Water wash is normaly done in air cooler boxes sections trough 2 inch lines. I think you have to ponder a modification control in your CDU overhead wash water injection.
at your service conditions I think you can use a carbon steel hic resistent according to NACE Requirements
see the link below
https://masteel.co.uk/products/hic-steel/
At your working pressure I would go for elbows, instead of hot bending. Hot bending put some problems of ovalizing and extrition (loss of thickness) wich is bad for pigging services.
In addition to what Pierreick said, your security service must take appropriate measures to prevent potential accidents, in the vicinity of the unit subjected to blowing, with delimitation of the area and warnings of possible hazards.
Passivation is used in austenitic to create an homogeneous oxide layer to prevent air exposition corrosion. Soaping the surface of welds with nitric or citric acid creates a very thin layer of oxid and dissolves free iron from surface, wich seems to be benefecial for the SS.
In low points and if thermal insulation is not properly installed to avoid water and moisture ingress, as in API you mention the ppossibility of CUI can happens
