Tube for heat exchanger

[tiagols]

Hello everybody.I have a design heat exchanger and it is specified maximum design temperature of 335°C.However, the materials for seamless pipes and tubes available in ASME Part B(SB338 and SB861) has maximum design temperature 315°C, as ASME Part D.Do you have any other suggestions to titanium tube?
Best regards!

 

[SnTMan]

tiagols, if you are stuck with Ti, maybe you can lower the design temp for the tubes. Very much depends on the service, owner preferences, etc.

Otherwise you are looking for a tube material that meets the temp requirement, plus the service.

Regards,

Mike

 

[tiagols]

Dear Mike,
The design temperature can not be changed.
I thought of the possibility of using a tube 1 1/4Cr-1/2Mo, what do you think?

 

[SnTMan]

tiagols, other than meeting the design temp it would seem a poor choice for service reasons if Ti was intially condsidered necessary.

I really can't give a useful opinion, only someone who is intimately familiar with the process, desired cost, life, etc can.

Regards,

Mike

 

[moltenmetal]

Likely some dumb-@ss has confused the design metal temperature of the tubes in an exchanger with the hot stream max inlet temperature or MAWT. Or perhaps they added some design margin on the correctly selected MAWT, thinking "what's 50 degrees C between friends- all it's going to do is reduce the stress values a bit and give us a little extra thickness" as if they were dealing with a stainless steel or the like.

If one of those things above isn't at play, Ti's the wrong material for your process, and without knowing your process intimately nobody is going to be able to find you an acceptable substitute.

 

[gr2vessels]

tiagos, you have to state the reason for selecting titanium tubes first place. Then you can get appropriate suggestion for a replacement material.
cheers,
gr2vessels