I assume it is in sulphur recovery area, where large diameter pipe with low
pressure ar eemployed for claus process. Acid gas is content, D/T ratio is
employed may be for pupose of ovalizitaion issue.
With 12.7 mm you are getting 120 which is quite high, with 15.25 you may be
able to achieve the required ratio, but it will create lot of other issues, like
stress analysis, in particular for nozzle loadings, cost , etc.
On other side if you think to use internal stiffener ring, it could also create
lot of problem, rings itself may cause corrosion (cervice in particular) issue
depending on process condition as well as testing method. Fabrication itself
will be an issue.
So do discuss the pros and cons with involved parties, i.e. Licensor (if
sulphur, could be BV) and your stress, process & metalugry specilaist and civil
dept.
Good Luck and do share the outcome.
Dear All,
Pipe Material is A691 Gr. 1.1/4 CR CL.22
Thickness for pipes under internal pressure is calculated as per ASME B31.3 Para 304.1.2.
As per licenser requirement D/t ratio must not exceed 100.
In one of the piping class for NPS 60 the thickness obtained is 12.7 mm but it does not meet D/t ratio criteria.
My question is : Can we use stifferner ring instead of increasing pipe thickness because if we increase pipe thickness then we have to perform PWHT according to B31.3. Stifferner ring is calculated as per ASME Sec VIII Div. 1. Can stifferner ring compensate the thicknesses for pipes having internal pressure.
Please suggest.
Thank you & Best Regards
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Received on Fri Dec 01 01:04:00 2006
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