Use of Admiralty Brass - High Temp CW Service

[NickelMet]

Does anyone have information regarding the use of Admiralty Brass tubing bundles in cooling water service (tube side @ 100 deg F) and naphtha service (shell side @ 150-300 deg F)?

A history of failures, fouling concerns, etc. is what I'm interested in.

Thanks

 

[PAN]

Admiralty brass should be acceptable in your service. Do you have any specific problems in your existing cooler/condenser? Enough water flow rate can decrease fouling in tubes.

 

[NickelMet]

PAN:

Our problem is that someone decided about 20 years ago to replace existing Adm. bundles with carbon steel. This sacrificed a good life of 16+ years with a poor life of <7 years. And, this was replicated several times over that 20 year span.

Our CW system does have problems with flow, though I am unaware of the rate in this exchanger at this time. It's a systemwide problem that is being addressed over the next 18 months with upgrades.

My concern - being new to this field of corrosion - stems from a comment made by an &quot;old timer&quot; who seemed to remember problems with Adm. bundles at high temperatures. The only thing, I can't find any supporting evidence as such.

Thanks.

 

[PAN]

Both fouling and corrsion rate in carbon steel are higher than admiralty brass. However, as copper alloy tubes cost over 3 times as much as carbon steel,if you can have sucessful cooling water treatment, the carbon steel tubes are estimated to serve over ten years.

In my understanding, 150-300 degree F is not a high temperature service for admiralty brass.

 

[NickelMet]

Thanks for the information PAN.

 

[kpandaz]

Try to use sacrificial anodes plates as well.
I agree that Admiralty brass is better that CS for these
services

 

[25362]

Admiralty brasses UNS numbers C44300, C44400, C44500 increase their resistance to dezincification (dealloying) -happening sometimes in slow-moving or stagnant waters- by small additions of phosphorous (0.02-0.06%). These brasses have largely replaced much older admiralty -unhinhibited- brasses.

 

[NickelMet]

Thanks all. The information is good that you have provided. Now, if I can just get the team to bite on replacing carbon steel bundles with admiralty bundles!

Thanks again!
Brent