Which is better for Heat Exchanger Tubes copper nickel 90/10 or 70/30?
Which is better for Heat Exchanger Tubes copper nickel 90/10 or 70/30?
(OP)
I'm researching both Copper Nickel 90/10 and 70/30 as possible tube materials for heat exchangers as an alternative to Admiralty brass which the company has been usuing and is looking to replace. Basically I want to know if anyone has had experience with these materials and if they are ideal for erosion and corrosion resistance, and if they have sufficient heat transfer coefficients.
Thanks
Thanks





RE: Which is better for Heat Exchanger Tubes copper nickel 90/10 or 70/30?
Thermal performance no real difference. The copper-nickel has better corrosion resistance in comparison to brass. The final selection really depends on service conditions followed by cost.
RE: Which is better for Heat Exchanger Tubes copper nickel 90/10 or 70/30?
In my area there is a lot of OTCW with admiralty brass tubes that have been replaced with 90-10 cupronickel, although it is not immune to the usual suspects (ammonia, shock chlorine treatment). I believe that in seawater applications the 70-30 is more resistant. The Nickel Development Institute (NiDI) could probably help you.
www.nidi.org
RE: Which is better for Heat Exchanger Tubes copper nickel 90/10 or 70/30?
CuNi works well if you have moderate flow rates, it has problems with stagnation and high velocity. It is also sensitive to S compounds.
The alloys are usually used one or two gauges lighter than brass.
Go to copper.org and do some research there.
= = = = = = = = = = = = = = = = = = = =
Plymouth Tube
RE: Which is better for Heat Exchanger Tubes copper nickel 90/10 or 70/30?
RE: Which is better for Heat Exchanger Tubes copper nickel 90/10 or 70/30?
It all depends on your service.
Regards,
Mike
RE: Which is better for Heat Exchanger Tubes copper nickel 90/10 or 70/30?
rmw
RE: Which is better for Heat Exchanger Tubes copper nickel 90/10 or 70/30?
RE: Which is better for Heat Exchanger Tubes copper nickel 90/10 or 70/30?
If you don't like the conductivity of 90/10 you sure won't like Ti or 2205.
Regards,
Mike
RE: Which is better for Heat Exchanger Tubes copper nickel 90/10 or 70/30?
RE: Which is better for Heat Exchanger Tubes copper nickel 90/10 or 70/30?
We did the erosion testing at 134 ft/sec in seawater.
What was your flow in the brass, 7 ft/sec?
If so then at 12 ft/sec with 0.028" SEA-CURE you will have about 30% increase in overall heat transfer than you had with 0.049" brass.
Flow velocity is your friend.
You would need to buy info from HEI. Their recommendations are not based on erosion resistance.
= = = = = = = = = = = = = = = = = = = =
Plymouth Tube
RE: Which is better for Heat Exchanger Tubes copper nickel 90/10 or 70/30?
It is funny that you mentioned that because I was doing research on the Sea Cure and it really does look like a good material. The only drawback that I read was that it isn't so good with fouling resistance due to no copper in its composition.
Well we did have velocities as high as 12 ft/s in the exchangers and we believe it caused erosion corroion problems with Admiralty brass tubes because it isn't designed for such high velocities.
So have you seen Sea Cure being used for ordinary shell and tube heat exchangers??
RE: Which is better for Heat Exchanger Tubes copper nickel 90/10 or 70/30?
Here is a link that will answer several of the questions that you have ask in this thread (and a paper that I wasn't familiar with - and one I need for other purposes, so thanks. I think the velocity recommendations in this paper are much more realistic for the 'better than copper' alloys.
ht
You were certainly right in your conclusions regarding using brass in a 12 fps application. Sheesh. And, yes, copper and brass do build up a nice patina resistant to further corrosion, but those velocities will wash it right off.
I for one am a huge fan of SeaCure. If there is a better metallurgy for low (meaning not high) temperature applications with all the stuff that can be found in less than DI water I want to know about it. I haven't found one I think to be better on an 'all around' basis.
What is causing your fouling?
rmw
RE: Which is better for Heat Exchanger Tubes copper nickel 90/10 or 70/30?
RE: Which is better for Heat Exchanger Tubes copper nickel 90/10 or 70/30?
Here is another good read on Cu-Ni. It is a pitch for SeaCure, but it goes into why one would want to make that change.
http:/
The author has a background in copper based tubing as well, so this isn't just a lot of hype.
rmw
RE: Which is better for Heat Exchanger Tubes copper nickel 90/10 or 70/30?
http://mexel.fr/products-solutions/mexel-432/
This stuff coats surfaces and then slowly breaks down. In the process things that stick to it get shed off into the discharge.
It is about the option you have to slow scale formation in a once through system.
Using a hard tube alloy like SEA-CURE, with a plan to mechanically clean on a regular time table will go a long way to keep the unit running.
= = = = = = = = = = = = = = = = = = = =
Plymouth Tube