Tube material in air-cooled heat exchanger 1

[Mohsen_81]

Hi Gents,

Can you introduce a reference to specify the material for tubes in aircoolers?
In specific, what could be the proper material for tubes in an air cooler as a steam condenser (steam inlet and condensate outlet)?

Thanks

 

The general design goal is to optimize the tubes (diameter, wall, number, arrangement) for heat transfer, choosing a material that is sufficiently corrosion-resistant while compromising thermal efficiency as little as possible. In clean shell side environments you can enhance heat transfer with finned tubes.

But rather than repeat what others have done, start by asking what is the current industry standard.

"Everyone is entitled to their own opinions, but they are not entitled to their own facts."

 

[EdStainless]

There have been many large-scale air-cooled condenser installations, you should be able to find plenty of papers written about them.
I have seen them in stainless steel, but I presume that other materials have been used.
You cannot use pure Cu, but you could use various brass alloys, as long as you can control the Cu pickup.
You cannot use carbon steel because of the Fe that gets into the condensate.
The biggest problems with these are related to flow losses, the steam does not move very well inside the tubes.
And vacuum leaks. Given how low the pressure needs to be keeping air out is a major undertaking.

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P.E. Metallurgy, consulting work welcomed

 

[CuMo]

We have used ASTM B163 UNS N04400 (MONEL); ALUMINIUM FINS GR.1060 for air cooled heat exchanger that carries hydrocarbons.
But that's probably way too expensive for your application.
Probably finned ASTM A179 tubes could do it.

Example from the internet.

http://www.sunnysteel.com/astm-a179... finned tubes are also,the fin from the tube.

See API 661.

 

[EdStainless]

For steam condensers (such as with power plants) 80% of the air-cooled condensers are stainless steel tubes.
Usually with pressed on Al fins.
The tubes tend to be fairly large, and a great number of them in parallel. And they are rather short.
Steam flow is a real issue, so the headers tend to be large also. And make sure there is good slope for drainage.
Many of these installations have automatic washers to clean the air side.
It has become more common to back an ACC with a water-cooled condenser to reach lower pressures and aid removal of non-condensables.

= = = = = = = = = = = = = = = = = = = =
P.E. Metallurgy, consulting work welcomed