heat exchangers of 9 bar inside a pressure vessel of 4 bar 3

[Silje]

Hi,
the first time that we have to design a pressure vessel with heat exchangers inside in ASME. Our tubes are section 31,3. That means, we can build them according to AD2000 but only the vessel is designed in ASME. Normally the heat exchangers belong to the tubes and we don't need to buy them in ASME, but what if they are inside. Two people told me, no, they don't have to be in ASME, but you need suitable provisions if they crack. We have a pressure relief if the the pressure rises over 4 bar, but if they would save the vessel if the pressure immediately rises up to 9 bar, I don't know. What is suitable? any ideas what to do, to make the assembly save?
What about the name plates, there will be 8 heat exchangers inside the vessel, do we need one plate for each or is it seen as one system? Any experience about this?
Would be soooo great if anybody out there has experience with this.
Greetings Silje

 

[innovation2]

Please upload a sketch.

Thanks

 

[Silje]

at your service, thank you for trying to help!
Silje

 

[SnTMan]

Silje, First, I think the jurisdication of installation will have the say on compliance w/ ASME / 31.3 / AD2000.

Assuming we are talking Sec VIII, Div 1, there are rules for Combination Units, see UG-19, UG-16 and UG-31.

I believe each of your coils will need a nameplate, see UG-116 and (j). See also UG-120 and (b).

A 4 bar PRV on the main vessel would presumably work, if it has enough relieving capacity, but see UG-125. A 10% overpressure is often allowed.

I think you need some serious conversation with the owner / user / jurisdiction.

Regards,

Mike

 

[marty007]

Silje,

With respect to your tubes being B31.3, take a look at Fig. 300.1.1 in ASME B31.3. The scope of B31.3 does not cover piping within a pressure vessel, this piping should be designed per the code rules of the pressure vessel.

Cheers,
Marty

 

[gr2vessels]

Marty's right, this is just another ASME VIII pressure vessel with internal heat exchanger(s), also subject of ASME VIII code. Refer to the directions from SnTMan. You can design the exchanger (are they plate exchangers?) as per the appropriate API code, still being in accordance with ASME VIII. The stab-in heat exchangers are also common in the industry.
Cheers,
gr2vessels

 

[Silje]

Thank you all! I checked the parts in B31.1 and in UG 19. Definitely, the heat exchangers must be in ASME.
greetings Silje