Titanium tubesheet Clad of Solid?

[Peter113]

Hello to all,
i have a H&E with titanium tube SB-338 Grade 2. Providing that the type is BES, is it possible to use a clad titanium tubesheet (shell side) or it must be solid? What about baffles?
Thanks
Peter

 

[stanweld]

It depends what the service is on both sides.

 

[jehan17718]

Peter113,

You need to check if whether both the shell and tubeside require titanium as the MOC.

Since titanium is not weldable with non- titanium products, the tubesheet is required to be cladded with titanium. With this, the Ti-tube to tubesheet joint can be seal welded or strength welded. Typically, we use a 10mm thick Ti cladding on the channel side irrespective of the tubesheet thickness. Occassionally a groove is also made in the Ti cladding and the tube is expanded.

You need to check if whether both the shell and tubeside require titanium as the MOC. in the current csase you have not specified this in your post. Be advised that the cost of a solid Titanium forging as a tubesheet will be tremendous and will be ruled out.

Hope this helps.

-jehan

 

[SnTMan]

Peter113, as noted by jehan17718 your materials of construction must be carefully considered, since Ti is much more noble than CS, the CS will preferentially corrode and under some circumstances this can result in failure in a short time. I would expect that Ti is required on the tubeside, but you must confirm. If so, all shellside materials may be CS.

I would expect as a minimum the tubesheets would be clad on the tubeside.

Next, you need to determine the floating head cover material. If Ti is required here, it will pretty much have to be solid.

It is fairly common to apply internal coatings to CS channels with Ti tubes and clad tubesheets to protect the CS and anodic protection may be used as well.

If it turns out that Ti is required on the shell side, your only option is likely to be solid Ti construction.

Regards,

Mike

 

[EdStainless]

If you can use clad with your service then you MUST seal weld the tubes in addition to rolling. you can't relay on the tube to tubesheet joint for a seal when it is only a few mm thick.

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Plymouth Tube

 

[Peter113]

Thanks for your collaboration,
i can give you more information. The corrosive fluid (vapours from atmospheric distillation column) goes through shell side. The tube side fluid is Storaged crude.
I would like to have the following from you:
1. Solid or clad (only shell side) tubesheet.
2. Would it be recommend to install sacrifices anodes on shell side or any internal coating?
3. MOC of baffles. Could be Tp304?
Regards
Pedro

 

[stanweld]

Peter113,
What is the current corrosion protection of the shell? Clad with stainless steel? Internally coated?

Whereas you have stated that the shell side is vapor, sacrificial anodes will not perform. If water condensation will occur; how much?

 

[Peter113]

Maybe i misexplained my query. Currently, we are defining the MOC since this equipment is to be build. The equipment is a overhead condenser atmospheric column, therefore, condended water is expected to happen with HCl dissolved due to the combination downstream of temperature and dissolved salts in the crude. Our Client is requesting to use titanium tubes by Contract with no chance to discuss if it is necessary or not. Now, what is your opinion/recommendation for the MOC for the different parts (shell side/tube side/tubesheet/internal elements?

Regards
Peter

 

[stanweld]

Monel alloy is often employed at the top of the crude column and may be specified for your shell side corrosion protection. I cannot provide definitive information.