corrosion in cooler system

[MAH82]

we have cooling system for our Generator. this system includes the directly air cooling heat exchangers(fin fan system), directly generator cooler and interconnection piping. we have used the water flushing to clean our pipes but we have got the rust inside the pipes and we dont no what is the situation in side the heat exchangers.our pipe are carbon steel and the cooler pipes are cupper. we need a procedure to remove all rust from pipes which would not damage the cupper pipes and any thing else. any help would be appriciated.

 

[kenvlach]

Absent more detailed information, I would treat as an automotive cooling system.
Add heavy duty radiator cleaner per instructions on can -- usually operate 1/2 hour, then water flush, neutralizer, and more water flushing.
Refill with 50 vol% automotive coolant & purest water available. Commercial products have corrosion protection for both ferrous & non-ferrous metals.
Also, install dielectric unions between the steel pipes & copper tubing (if directly plumbed w/o rubber hose).

 

[metengr]

We have large generators that contain 90/10 copper/nickel fin-type hydrogen coolers. These heat exchangers are embedded in the stator and are supplied cooling water from carbon steel piping in the plant.

We do not treat the low pressure service water (fresh water) and have never attempted to clean the ID surface of the carbon steel piping to the generator coolers. Most of the carbon steel piping has been in service for over 30 years. The carbon steel piping has developed a rather thick layer of rust with tubercles (as expected). From time to time we have had to replace sections after thru-wall pits reached a point where we had leaks.

we need a procedure to remove all rust from pipes which would not damage the cupper pipes and any thing else. any help would be appriciated.

Why? Do you treat the service water for this cooling system? If not, you will reform the rust deposits.