Air Cooled Exchangers : Experience with Coatings for air side fouling.

[jamesbanda]

We are looking at replacement of an air cooled exchanger on site, and i've been asked to considered a coating on the fans to reduce air side fouling..Heresite is the name..

what is users expereince with those..
(we are near the coast..)

i've not seen my company use these before..

 

[speco]

jamesbanda,

I'm not an end user, but a designer and rep for an air-cooled exchanger manufacturer. So you can take what I say with a large block of salt. That said, the usual to the problem of fin-side corrosion is extruded, not coated fins. I have seen Heresite coatings used for some bizarre applications, and it not a good choice for air coolers. The Heresite phenolic coating must be baked on. Usually this meand dipping the entire tube bundle in the Heresite solution prior to baking. I don't think you will find a cooler manufacturer who is willing do do that. Also, it's extremely(!) expensive.

On the other hand, extruded fins are commonly used on offshore platforms, or on island or coastal installations. If your process temperatures are not ridiculously high, it's definitely a better way to go.

If you think you do need a coating, a material called "copon" has been used on finned tubes. You might look into that.

Regards,

Speco (

http://www.stoneprocess.com)

 

[EnergyMix]

Speco,

Hopefully I'm not sidetracking the thread too much, but what information do you have about the effects of copon (or any other products) on the heat transfer capability?

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[speco]

EnergyMix,

I checked with my manufacturer on your question. We're researching it a bit to try to find a better answer. In the meantime, he's estimating it at approximately 5% (and possibly higher) additional thermal resistance based on a 2 mil coating thickness. Using coated finned tubes is really quite rare, so this is not an easy question to answer. I would expect it to be less that 5%, but it's always better to be on the safe side with heat transfer questions.

Speco

 

[SJones]

Am I reading the question right - coating of the fans,not the tubes? Also, what is the nature of the 'fouling' - is it corrosion, or simply deposit build up?

Steve Jones
Materials & Corrosion Engineer

http://www.linkedin.com/pub/8/83b/b04

All answers are personal opinions only and are in no way connected with any employer.

 

[speco]

SJones,

Your right. The original question referred to fans, not fins. However, since he alse referred to fouling, it appears that his intent was to ask about coatings on heat transfer surface. Maybe he will respond to clear things up.

Speco