Vapor Distribution Belts

[Afox88]

Does compress handle vapor distribution belts for a heat exchanger or do I have to model it as a separate vessel? I did not see the option.

Please advise,

 

[Eddy1988]

Afox88,

COMPRESS has a feature to evaluate Integral Flat Head with large single circular central opening, Appendix 14.

Here is a story that could help you. We were asked to evaluate a heat exchanger with a vapor distribution belt. We first tried the Appendix 14 approach and the results were a required thickness for vapor distribution belt that was very thick (over 2" for MAWP=150 psi). We decided then to evaluate the vessel by use of FEA.

Hope it helps,

Eddy

 

[marty007]

Eddy1988 - How did you justify that approach to your AI? Paragraph UHX-4(c) provides rules on how to handle a vapor distribution belt, which then refers to Appendix 5, or later in UHX depending on how the internal shell is handled. U-2(g) should only have been applied if there are no rules provided in ASME VIII-1.

Afox88 - As far as I know, Compress does not address vapor distribution belts. Would be a good addition though!

 

[Afox88]

Thanks for the feedback. It would be a good feature.

 

[Eddy1988]

marty007- We did not justify the approach with a local AI. You are correct in saying that the Code does provide some guidance regarding vapor belts, I should have mentioned in the previous post. The particular vessel that I described on the post above was not applicable to Mandatory Appendix 5 in the Code; therefore we used the U-2(g) approach.

 

[CRL11]

I have reviewed many of these vessels and I can say that COMPRESS will not handle this correctly. In my case an FEA was performed for each of these vessels to verify the integrity of the area.

 

[Afox88]

Now that I have a little more experience with compress, I normally run the vapor belt as a separate Division 1 vessel to determine the thickness of the belt and the nozzles. Then I simply perform the closure in an excel document I created based upon Appendix 9 calculations.