Characteristic 70-30 Cu Ni Tube in HP feedwater heater

[semarang]

Thank's to the reply.
Back to the topic itself, i still need a confirmation about the material characteristic, especially 70-30 Cu Ni based on water velocity's influenced to the corrosion rate.
Book says that in Cu tube, the water velocity in feedwater should not more than 2 m/s. Is it applicable for the 70-30 Cu Ni tube? And what is the main function of Ni?

Regards

Dwi Handoyo S

 

[MJCronin]

semarang,

I am not sure I understand your question, but here goes... I am guessing that you are refering to High Pressure Feedwater Heaters in thermal power plants.

A USA Standard, developed by the Heat Transfer Institure (HEI) provides guidelines for Feedwater Heaters on maximum tubeside water velocities, depending on the tube material.

As I recall, 70-30 copper nickel has a much lower maximum velocity than stainless steels

See:

http://www.heatexchange.org/pub/default.htm

What are your operating conditions ?

MJC

"There comes a time in the affairs of man when he must take the bull by the tail and face the situation." W.C. Fields

 

[vpl]

semarang

Here's a link to a page on various material properties:

http://www.nbm-houston.com/metals/nickel715.html

From this link you can compare the properties of plain copper and the copper-nickel and answer the question about "what is the main function of the nickel". It also gives several specifications which you can look at to determine limits on tube velocity.


Patricia Lougheed

Please see FAQ731-376 for tips on how to make the best use of the Eng-Tips Forums.

 

[finman]

Cu Ni tubes are used alot in Marine Heat Exchangers to give superior wear characteristics against erosion by seawater based materials ie sand and shell particles etc. The Ni content gives a tougher material than straight Copper. On the flip side the heat transfer is not so good.

However I have not come across a marine feedwater heater with CuNi tubes, most are steel as the feedwater is filtered & treated.

Some more details on your application may be usful to us.

 

[semarang]

Thank's for all your reply.
These help me much.



Dwi Handoyo S