Copper Corrosion in condensate return boiler

Helo,

I have problem in our condensate return of boiler with 180 bar.

The copper in condensate return before entering catrige filter or Condensate Polisher Unit is very high (above 15 ppb).

We are using chemical as corrosion inhibitor is cyclo hexalamine that sometime decomposed to NH3.

We believe that our chemical is suitable for high pressure boiler.

Cu in Feed Water, Boiler water and steam are good. We suspect this problem is coming from other unit that having copper erosion. But technically we cannot analyse this mechanical problem.

Please advise for this problem and give some referencies for copper corrosion in condensate treatment.

Many thank for all.

We have had similar conditions in our plant. Basically, you may check the metallurgy of the different equipments of your steam condensate system. In our experience, high pH of steam condensate in a surface condenser with copper alloy tubes made copper release. I recommend to analyze copper in different points of your steam balance and compare it to your equipment metallurgy to confirm the source. Please also check letter No 7330 to get to know a little bit more about copper in BFW.

Best regards.