5 replies to this topic

[Diep Thanh]

Dear experts,

Now I am having a problem of choosing material for a heat exchanger. Mine is C4 product cooler: shell-side: C4+, tubeside: seawater. What is material should be applied for shellside and tubeside?

 

A little bird tells me that we should not use carbon steel in case of seawater? Is it admiralty acceptable?

For C4+, carbon steel is acceptable right? 

Could you please give an explanation?

 

Thank you very much and appreciate all!

[Atttyub194]

Dear Diep Thanh:

 

Good day!

 

I will give you a brief on material selection with some recomeendation maybe day after tomorrow.  Hope this will be okay to you.

[breizh]

Hi ,

You may find some pointers reading these brochure and paper .

 

 

 

Hope this helps

Breizh

Edited by breizh, 31 August 2015 - 06:48 AM.

[fallah]

Diep Thanh,

 

In general, the material for shell/shell cover... should be LTCS and for tube/tube sheet/channel/channel cover...should be Titanium...

[shamir]

IN TUBE SIDE TITANIUM SHOULD BE USED. I have worked in manufacturing of Bromine in which we pump sea water via Pump for which Titanium is best. So Please refer the properities of Titanium and go forward.........

[Art Montemayor]

Diep Thanh:

 

In order to obtain detailed and accurate advice and recommendations, you should furnish a detailed description of the TYPE of heat exchanger that you are proposing as a Butane cooler using seawater on the tubeside.  The application calls for some special attention and design due to the seawater and the temperatures involved would also help.  My experience in using seawater in offshore platforms is as follows:

• The basic documentation supplied by Breizh is, as would be expected coming from him, excellent detailed information on the available duplex stainless materials available to combat seawater corrosion.  However, read the document very carefully and consult with world-recognized fabricators of duplex materials to fully understand which alloys are applicable with the specifications you impose on the mechanical design and temperatures involved.  There are many, many alloys of Duplex and Super Duplex and only experts can select the applicable ones.  Note that eventually some corrosion must be tolerated (however small) with the duplex material.
• Titanium, as Fallah has stated is the best material of choice, experiencing practically nil corrosion.  However, the material price (as would be an expected tradeoff) is higher than other materials.  That is why in most applications the seawater is put into the tubeside in spite of the low pressure therein.  The channel or bonnet as well as the tubesheet are usually laminated or layered in Titanium with the sea water piping being plastic-lined internally.
• The basic TEMA design I have employed with Titanium for this type of application is a BEU.  This type allows for free thermal expansion with a minimum of stress on the tubes and the welding.  The tradeoff in this design is that the required size is larger than a carbon steel design due to the lower velocities involved in both the shell and tubesides and the inherent temperature factor in a U-tube design.  However, the benefits, including nil stresses, are allowance for ease of shell and tube inspections and a minimum of tube-to-tubesheet seal welding.  Baffle design should be carefully analyzed for avoidance of baffle and tube damage due to rubbing each other.  Very specific and detailed welding procedures should be applied to the Titanium materials.
• Of course you can use Admiralty.  This was the first alloy to be used on ships for steam condensers.  However, prepare yourself for constant maintenance concerns and applications.  It will corrode - as most materials - due to the seawater corrosive tendencies.